390 results on '"R. Iwasaki"'
Search Results
2. Self-reported health and behavioral factors are associated with metabolic syndrome in Americans aged 40 and over
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Ying Liu, Ifeoma D. Ozodiegwu, Jeffrey C. Nickel, Kesheng Wang, and Laura R. Iwasaki
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Physical inactivity ,Diet ,Weighted logistic regression ,Medicine - Abstract
To determine whether behavioral factors differ among metabolic conditions and self-reported health, and to determine whether self-reported health is a valid predictor of metabolic syndrome (MetS). A total of 2997 individuals (≥40 years old) were selected from four biennial U.S. National Health and Nutrition Examination Surveys (2007–2014). A set of weighted logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs)Individuals with light physical activity are more likely to have MetS and report poor health than those with vigorous physical activity with OR = 3.22 (95% CI: 2.23, 4.66) and 4.52 (95% CI: 2.78, 7.33), respectively. Individuals eating poor diet have greater odds of developing MetS and reporting poor health with OR = 1.32 (95% CI: 1.05, 1.66) and 3.13 (95% CI: 2.46, 3.98). The aforementioned relationships remained significant after adjustment for demographic and socio-economic status. A potential intervention strategy will be needed to encourage individuals to aggressively improve their lifestyle to reduce MetS and improve quality of life. Despite the significant association between self-reported health with MetS, a low sensitivity indicated that better screening tools for MetS, diabetes and cardiovascular disease are essential.
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- 2017
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3. Markers of Paradental Tissue Remodeling in the Gingival Crevicular Fluid and Saliva of Orthodontic Patients
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Taylor E. Glovsky and Laura R. Iwasaki
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- 2021
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4. Expert consensus on Didactic Clinical Skills Development for orthodontic curricula
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Vesna Lea S. Ferrer, Christopher J. Van Ness, Shankar Rengasamy Venugopalan, Laura R. Iwasaki, Jeffrey C. Nickel, and Cynthia C. Gadbury-Amyot
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Medical education ,Consensus ,Delphi Technique ,020205 medical informatics ,Delphi method ,Expert consensus ,Cognition ,030206 dentistry ,02 engineering and technology ,General Medicine ,Focus group ,03 medical and health sciences ,0302 clinical medicine ,Scale (social sciences) ,0202 electrical engineering, electronic engineering, information engineering ,Humans ,Learning ,Clinical Competence ,Curriculum ,Psychology ,Competence (human resources) ,Clinical skills - Abstract
PURPOSE/OBJECTIVE Competence is expected of each beginning dentist and orthodontist. However, the broad definition of competence presents a challenge to academic programs in identifying the level of cognition for students to achieve competence. This study aimed to determine the Didactic Clinical Skills Development curriculum content and competency in predoctoral and advanced education orthodontic programs. METHOD A modified Delphi method with a consensus threshold of 70% was employed using an expert panel of academic orthodontists. RESULTS Round One (n = 26) identified that all topics proposed by a focus group were necessary, except for predoctoral Appliances, which was at 65%. Round Two (n = 23) included subtopics of Appliances to confirm the lack of consensus, plus subtopics of all the other topics and the level of cognition required for each subtopic. The expert panel reached a consensus that all 24 subtopics, hence all topics, were necessary. In Round Three, subtopic responses in Round Two were assigned a value between 1 (remember) and 6 (create) to generate a hierarchical level-of-learning scale. Mean values were calculated for each subtopic response. For all subtopics, the mean level of cognition for predoctoral education was at understand; for advanced education, it was at evaluate. CONCLUSION This consensus suggests that, to be deemed competent, beginning dentists must learn these topics and subtopics in the cognitive domain of understand, and beginning orthodontists in the cognitive domain of evaluate. This study showed an expert consensus on Didactic Clinical Skills Development orthodontic curriculum content and a panorama of educational objectives that could be used as a template for curriculum design.
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- 2021
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5. Three‐dimensional conformal radiation therapy for canine aortic body tumour: 6 cases (2014–2019)
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M Murakami, S Goto, Takashi Mori, Hiroki Sakai, R Iwasaki, Kentaro Kitagawa, and A Maeda
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medicine.medical_specialty ,040301 veterinary sciences ,medicine.medical_treatment ,Conformal radiation therapy ,Aortic body tumour ,Asymptomatic ,0403 veterinary science ,Dogs ,Neoplasms ,medicine ,Animals ,Clinical significance ,Dog Diseases ,Small Animals ,Retrospective Studies ,Lung ,Respiratory distress ,business.industry ,0402 animal and dairy science ,04 agricultural and veterinary sciences ,Aortic Bodies ,040201 dairy & animal science ,Radiation therapy ,medicine.anatomical_structure ,Radiology ,Radiotherapy, Conformal ,medicine.symptom ,Aortic body ,business - Abstract
Objective To determine the feasibility of three-dimensional conformal radiation therapy for canine aortic body tumours. Materials and methods Medical records of dogs that had undergone three-dimensional conformal radiation therapy with presumptive diagnosis of aortic body tumour were reviewed for clinical characteristics, treatment modality and outcomes. Results Eight dogs were diagnosed with aortic body tumour and were treated with three-dimensional conformal radiation therapy. One dog had proliferation of a mass in the right atrium during treatment and died of respiratory distress. Another dog did not undergo follow-up CT to evaluate the treatment response due to the increased blood urea nitrogen values. The remaining 6 dogs were included in the case series. Radiotherapy was performed using a median dose per fraction of 7 Gy (3.3-7.14 Gy), a median of seven divided doses (7-15) and a total median dose of 49 Gy (45-50 Gy). The median number of CT scans during the follow-up period was 5 (range: 3-8 times). CT revealed acute side effects in four dogs-grade 1 effects related to the lung (n = 4) and skin (n = 2). Self-limiting or asymptomatic late side effects (grade 1 lung-related effect) were observed in three dogs. After therapy, one dog demonstrated a complete response, another demonstrated a partial response and the disease remained stable in four animals. The median follow-up period was 514.5 (235-1219) days. After three-dimensional conformal radiation therapy, the aortic body tumour reduced gradually over time without regrowth in all these 6 dogs. Clinical significance In this small case series, aortic body tumours responded to three-dimensional conformal radiation therapy. Transient and self-limiting side effects of the treatments were common. Further controlled studies are required to prove the effectiveness and the safety of this intervention.
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- 2020
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6. 499 Treatment patterns in Japanese patients with generalized pustular psoriasis (GPP) with/without concomitant psoriasis vulgaris (PsV) and in elderly patients
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Y. Tada, R. Iwasaki, J. Guan, and A. Morita
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Cell Biology ,Dermatology ,Molecular Biology ,Biochemistry - Published
- 2023
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7. Night‐time autonomic nervous system ultradian cycling and masticatory muscle activity
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H. Liu, Laura R. Iwasaki, Michala Markova, Stefan Erni, Luigi M. Gallo, and Jeff C. Nickel
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Adult ,Male ,medicine.medical_specialty ,Temporal Muscle ,Orthodontics ,Electromyography ,Audiology ,Autonomic Nervous System ,03 medical and health sciences ,0302 clinical medicine ,Humans ,Medicine ,030212 general & internal medicine ,Ultradian rhythm ,medicine.diagnostic_test ,Masseter Muscle ,business.industry ,Ultradian Cycles ,Ultradian Rhythm ,030206 dentistry ,Bite force quotient ,Autonomic nervous system ,Otorhinolaryngology ,Masticatory Muscles ,Female ,Surgery ,Oral Surgery ,business ,Cycling ,Electrocardiography ,Masticatory muscle - Abstract
OBJECTIVES To test if there was a correlation between night-time masticatory muscle activity, as measured by duty factors, and ultradian cycling of autonomic nervous system (ANS) spectral powers in subjects without temporomandibular disorder (TMD)-related pain. SETTING AND SAMPLE POPULATION The University of Missouri-Kansas City School of Dentistry. Three women and four men of average ages 38 ±8 and 56 ± 17 years, respectively, gave informed consent to participate. MATERIAL AND METHODS Investigators taught subjects to record heart (electrocardiography, ECG) and masticatory muscle activities (electromyography, EMG). ECG recordings were analysed for ANS ultradian cycling by a polynomial fit to the ratio of sympathetic and parasympathetic spectral powers (ms$^{2}$ ). Masseter and temporalis EMG recordings were analysed over 20-minute epochs around peaks and valleys in the ANS ultradian cycles. Duty factors (% time of masticatory muscle activity/20-minute epoch) were determined relative to average threshold EMG (T$_{EMG}$ ) required to produce a given bite force (N). Regression analyses quantified relationships between normalized muscle duty factors and ANS spectral powers. RESULTS Subjects made a total of 27 sets of night-time ECG and EMG recordings that averaged 6.6 ± 1.1 hours per recording. Highest average duty factors were associated with T$_{EMG}$ of 1-2 N and showed cumulative masseter and temporalis activities of 9.2 and 8.8 seconds/20-minute epoch, respectively. Normalized masticatory muscle duty factors showed non-linear relationships with normalized sympathetic (R$^{2}$ = +0.82), parasympathetic (R$^{2}$ = -0.70) and sympathetic/parasympathetic spectral powers (R$^{2}$ = +0.75). CONCLUSIONS Night-time ANS spectral powers showed ultradian cycling and were correlated with masseter and temporalis muscle activities in adult subjects without TMD.
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- 2019
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8. Expert Consensus on Growth and Development Curricula for Predoctoral and Advanced Education Orthodontic Programs
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Cynthia C. Gadbury-Amyot, Laura R. Iwasaki, Christopher J. Van Ness, and Vesna Lea S. Ferrer
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Medical education ,Delphi Technique ,020205 medical informatics ,Delphi method ,Modified delphi ,Expert consensus ,Orthodontics ,Cognition ,030206 dentistry ,02 engineering and technology ,General Medicine ,Commission ,Education, Dental, Graduate ,Accreditation ,03 medical and health sciences ,0302 clinical medicine ,0202 electrical engineering, electronic engineering, information engineering ,Humans ,Curriculum ,Psychology ,Education, Dental ,Competence (human resources) - Abstract
Dental students and orthodontic residents must demonstrate competence in various areas prior to graduation. However, the Commission on Dental Accreditation (CODA) definition of competence is broad. The aims of this study were to obtain expert consensus on Growth and Development topics and subtopics in predoctoral and advanced education programs in orthodontics and to determine the level of cognition on the subtopics necessary to demonstrate learner competence. A modified Delphi method with a consensus threshold of 70% was used. In Round One, academic orthodontists who met the expert panel inclusion criteria were surveyed to determine whether a topic was necessary to the curricula. Round Two identified the subtopics under each topic and the level of cognition necessary to demonstrate learner competence using Bloom's taxonomy, which defines the ascending levels of remember, understand, apply, analyze, evaluate, and create. Round Three involved analyses and interpretation of Round Two results. The academic orthodontists determined that six topics (n=24) and 29 subtopics (n=15) were necessary for Growth and Development curricula. For all subtopics, they determined the mean level of cognition for predoctoral education was understand; for advanced education, it was analyze. This consensus on Growth and Development curricular content suggests that these levels are necessary for a beginning dentist and a beginning orthodontist to be deemed competent. Findings from this study can serve to guide curricular development and instruction by using the identified learning objectives to build instructional and assessment measures.
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- 2019
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9. Early Monitoring of Redox Status Based on Reduced Molecules Using In Vivo DNP-MRI for Cancer Treatment
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N. Koyasu, F. Hyodo, A.E. Elhelaly, S. Shoda, R. Iwasaki, H. Tomita, M. Takasu, T. Mori, Y. Noda, H. Kato, and M. Matsuo
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Cancer Research ,Radiation ,Oncology ,Radiology, Nuclear Medicine and imaging - Published
- 2022
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10. Pathological Assessment of Cardiac Radioablation to the Cavotricuspid Isthmus without Gating and Real-Time Tracking in Mini Pigs
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M. Matsuo, F. Hyodo, K. Hiroshi, R. Iwasaki, N. Takasugi, S. Nagata, T. Mori, H. Tomita, M. Ito, C. Makita, and T. Kumano
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Cancer Research ,Radiation ,Oncology ,Radiology, Nuclear Medicine and imaging - Published
- 2022
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11. Development of Highly Sensitive and Stable Nitroxyl Probe for Visualization of Free Radical Reaction Induced by X-Ray Irradiation
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T. Mori, F. Hyodo, R. Iwasaki, N. Koyasu, M. Ito, C. Makita, T. Kumano, and M. Matsuo
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Cancer Research ,Radiation ,Oncology ,Radiology, Nuclear Medicine and imaging - Published
- 2022
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12. A theoretical analysis of longitudinal temporomandibular joint compressive stresses and mandibular growth
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Riddhi J. Desai, Jeffrey C. Nickel, Ying Liu, H. Liu, Laura R. Iwasaki, and Sohyon Michelle Kim
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Orthodontics ,Adolescent ,Temporomandibular Joint ,Mandibular Condyle ,Repeated measures design ,Mandible ,Original Articles ,Condyle ,Temporomandibular joint ,Mandibular growth ,Bite Force ,medicine.anatomical_structure ,Compressive strength ,Biting ,Incisor ,Face ,medicine ,Humans ,Analysis of variance ,Child ,Mathematics - Abstract
Objectives To determine if temporomandibular joint (TMJ) compressive stresses during incisor biting (1) differed between growing children over time, and (2) were correlated with Frankfort Horizontal-mandibular plane angle (FHMPA, °) and ramus length (Condylion-Gonion (Co-Go), mm). Materials and Methods Three-dimensional anatomical geometries, FHMPA and Co-Go, were measured longitudinally from lateral and posteroanterior cephalographs1 of children aged 6 (T1), 12 (T2), and 18 (T3) years. Geometries were used in numerical models to estimate subject-specific TMJ eminence shape and forces for incisor bite-forces of 3, 5, and 8 Newtons at T1, T2, and T3, respectively. TMJ compressive stresses were estimated via two steps: First, TMJ force divided by age-dependent mandibular condylar dimensions, and second, modified by loading surfaces' congruency. Analysis of variance and Tukey honest significant difference post-hoc tests, plus repeated measures and mixed effects model analyses were used to evaluate differences in variables between facial groups. Regression analyses tested for correlation between age-dependent compressive stresses, FHMPA, and Co-Go. Results Sixty-five of 842 potential subjects had T1-T3 cephalographs and were grouped by FHMPA at T3. Dolichofacial (FHMPA ≥ 27°, n = 36) compared to meso-brachyfacial (FHMPA< 27°, n = 29) subjects had significantly larger FHMPA at T1-T3, shorter Co-Go at T2 and T3 (all P < .01), and larger increases in TMJ compressive stresses with age (P < .0001). Higher compressive stresses were correlated with larger FHMPA (all R2 ≥ 0.41) and shorter Co-Go (all R2 ≥ 0.49). Conclusions Estimated TMJ compressive stress increases from ages 6 to 18 years were significantly larger in dolichofacial compared to meso-brachyfacial subjects and correlated to FHMPA and Co-Go.
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- 2021
13. 3D Slicer Craniomaxillofacial Modules Support Patient-Specific Decision-Making for Personalized Healthcare in Dental Research
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Camila Massaro, João Roberto Gonçalves, Tengfei Li, Martin Styner, Lorena Vilanova, Lucia H. S. Cevidanes, Juan C. Prietro, Laura R. Iwasaki, Antonio Carlos de Oliveira Ruellas, Daniela Gamba Garib, Guilherme Janson, Marcela Gurgel, Marilia Yatabe, James Hoctor, Cauby Maia Chaves Junior, Karine Evangelista, Beatriz Paniagua, José Fernando Castanha Henriques, Jean-Christophe Fillion-Robin, Jonas Bianchi, Aron Aliaga-Del Castillo, and Jeffrey C. Nickel
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Biological data ,Computer science ,business.industry ,Data management ,030206 dentistry ,Data science ,Article ,030218 nuclear medicine & medical imaging ,Visualization ,03 medical and health sciences ,0302 clinical medicine ,Software ,Data extraction ,Analytics ,Personalized medicine ,Radiation treatment planning ,business - Abstract
The biggest challenge to improve the diagnosis and therapies of Craniomaxillofacial conditions is to translate algorithms and software developments towards the creation of holistic patient models. A complete picture of the individual patient for treatment planning and personalized healthcare requires a compilation of clinician-friendly algorithms to provide minimally invasive diagnostic techniques with multimodal image integration and analysis. We describe here the implementation of the open-source Craniomaxillofacial module of the 3D Slicer software, as well as its clinical applications. This paper proposes data management approaches for multisource data extraction, registration, visualization, and quantification. These applications integrate medical images with clinical and biological data analytics, user studies, and other heterogeneous data.
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- 2021
14. Gender differences in the association of periodontitis and type 2 diabetes
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Melanie Simmer-Beck, Jeffrey C. Nickel, Yang Yu, Peipei Duan, Laura R. Iwasaki, Ying Liu, and Laura Brown
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Adult ,Male ,National Health and Nutrition Examination Survey ,030209 endocrinology & metabolism ,Type 2 diabetes ,Logistic regression ,03 medical and health sciences ,0302 clinical medicine ,Sex Factors ,Diabetes mellitus ,medicine ,Prevalence ,Humans ,Obesity ,Periodontitis ,General Dentistry ,Socioeconomic status ,Scientific Research Report ,business.industry ,Age Factors ,030206 dentistry ,Odds ratio ,Middle Aged ,medicine.disease ,United States ,Diabetes Mellitus, Type 2 ,Socioeconomic Factors ,Female ,business ,Body mass index ,Demography - Abstract
Aims THE OBJECTIVE WAS TO INVESTIGATE IF GENDER DIFFERENCES EXIST IN THE ASSOCIATIONS BETWEEN PERIODONTITIS AND TYPE 2 DIABETES. DISPROPORTIONATE DISPARITIES BY GENDER WERE FOUND TO EXIST IN RATES OF BOTH PERIODONTITIS AND DIABETES WITH RESPECT TO DEMOGRAPHICS AND BEHAVIOURAL PREDICTORS THAT CANNOT BE EXPLAINED SOLELY BY THE WELL-ESTABLISHED ASSOCIATION BETWEEN THESE TWO DISEASES. Materials and methods MULTIPLE DATASETS WERE EXTRACTED FROM THE NATIONAL HEALTH AND NUTRITION EXAMINATION SURVEY (NHANES) 2009-2014, WHICH USED A STRATIFIED MULTISTAGE PROBABILITY SAMPLING TO OBTAIN SAMPLES FROM ALL CIVILIAN NON-INSTITUTIONALISED PEOPLE IN THE USA. BIVARIATE RELATIONSHIPS BETWEEN EACH EXPLANATORY VARIABLE AND PERIODONTITIS LEVEL WERE ASSESSED WITH ODDS RATIOS (OR) AND THEIR 95% CONFIDENCE INTERVALS (CI). A SET OF WEIGHTED LOGISTIC REGRESSION MODELS WAS USED TO INVESTIGATE THE ASSOCIATION DIFFERENTIATIONS BETWEEN PERIODONTITIS AND DIABETES BY GENDER. C-STATISTICS MEASURED THE GOODNESS-OF-FIT OF WEIGHTED LOGISTIC REGRESSION MODELS. Results THE PREVALENCE OF MODERATE-SEVERE PERIODONTITIS WAS 36.39% AND 22.71% AMONG PARTICIPANTS WITH TYPE 2 DIABETES AND WITHOUT DIABETES, RESPECTIVELY. TYPE 2 DIABETES WAS SIGNIFICANTLY ASSOCIATED WITH MODERATE-SEVERE PERIODONTITIS OR (OR = 1.47, 95% CI: 1.18-1.82) AMONG MALES EVEN AFTER ADJUSTING FOR DEMOGRAPHICS, SOCIOECONOMIC STATUS AND ORAL HEALTH BEHAVIOURS. THE AFOREMENTIONED RELATIONSHIP WAS NOT FOUND IN FEMALES. FURTHERMORE, DIFFERENT RELATIONSHIPS OF MODERATE-SEVERE PERIODONTITIS WITH BODY MASS INDEX AND THE USE OF MOUTHWASH WERE FOUND BETWEEN THE MALES AND FEMALES. Conclusions THE CURRENT FINDINGS SUGGEST THAT IMPORTANT IMPROVEMENTS IN THE DEVELOPMENT OF GENDER-SPECIFIC STRATEGIES IN PREVENTION, SUCH AS ORAL HOME-CARE, TO REDUCE THE HIGH PREVALENCE OF PERIODONTAL DISEASE AND MAINTAIN GOOD ORAL HEALTH ARE VITAL, AND ARE ESPECIALLY IMPORTANT FOR MALE DIABETIC PATIENTS AND THOSE WHO ARE AT HIGH RISK OF DEVELOPING DIABETES, SUCH AS THOSE WHO ARE OBESE.
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- 2020
15. Mechanobehavior and mandibular ramus length in different facial phenotypes
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R. Scott Conley, Luigi M. Gallo, Ying Liu, Laura R. Iwasaki, H. Liu, Paige Covington Riddle, Jeffrey C. Nickel, Yoly M. Gonzalez, and Robert G. Dunford
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Orthodontics ,Male ,Cone beam computed tomography ,medicine.diagnostic_test ,Temporomandibular Joint ,business.industry ,Cephalometry ,Radiography ,Electromyography ,Original Articles ,Mandible ,Temporomandibular joint ,medicine.anatomical_structure ,Phenotype ,Face ,medicine ,Mandibular plane ,Humans ,Female ,Analysis of variance ,business ,Mandibular ramus - Abstract
Objectives To test the hypotheses that mechanobehavior scores (MBS) were correlated with mandibular ramus lengths (Co-Go) and differed between facial phenotypes. Materials and Methods Subjects gave informed consent to participate. Co-Go (mm), mandibular plane angles (SN-GoGn, °), and three-dimensional anatomy were derived from cephalometric radiography or cone beam computed tomography. Temporomandibular joint (TMJ) energy densities (ED) (mJ/mm3) were measured using dynamic stereometry and duty factors (DF) (%) were measured from electromyography, to calculate MBS (= ED2 × DF,) for each TMJ. Polynomial regressions, K-means cluster analysis, and analysis of variance (ANOVA) with Tukey post-hoc tests were employed. Results Fifty females and 23 males produced replete data. Polynomial regressions showed MBS were correlated with Co-Go (females, R2 = 0.57; males, R2 = 0.81). Cluster analysis identified three groups (P < .001). Dolichofacial subjects, with shorter normalized Co-Go, clustered into two subgroups with low and high MBS compared to brachyfacial subjects with longer Co-Go. SN-GoGn was significantly larger (P < .03) in the dolichofacial subgroups combined (33.0 ± 5.9°) compared to the brachyfacial group (29.8 ± 5.5°). Conclusions MBS correlated with Co-Go within sexes and differed significantly between brachyfacial and dolichofacial subjects.
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- 2020
16. Psychosocial Scores and Jaw Muscle Activity in Women
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H. Liu, JoAnna M. Scott, Yoly Gonzalez, Jeffrey C. Nickel, and Laura R. Iwasaki
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Adult ,medicine.medical_specialty ,Temporal Muscle ,Electromyography ,Anxiety ,Patient Health Questionnaire ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Group differences ,Humans ,Medicine ,Women ,0501 psychology and cognitive sciences ,Dentistry (miscellaneous) ,050102 behavioral science & comparative psychology ,Muscle activity ,medicine.diagnostic_test ,Depression ,Masseter Muscle ,business.industry ,05 social sciences ,Temporomandibular disorder ,030206 dentistry ,Middle Aged ,Temporomandibular Joint Disorders ,Control subjects ,Jaw muscle ,stomatognathic diseases ,Anesthesiology and Pain Medicine ,Case-Control Studies ,Linear Models ,Physical therapy ,Female ,Neurology (clinical) ,Sleep ,business ,Psychosocial - Abstract
AIMS To test whether women with temporomandibular disorder (TMD)-related pain showed higher psychosocial scores and higher awake- and sleep-time jaw muscle activities (characterized by duty factors) compared to pain-free controls and whether psychosocial scores and the jaw muscle duty factors were associated. METHODS Subjects gave informed consent to participate. The Diagnostic Criteria for TMD (DC/TMD) were used for diagnosis of TMD pain, and 31 and 36 women were included in the TMD-related pain and control groups, respectively. DC/TMD Axis II instruments were used to determine psychosocial scores. Subjects self-recorded masseter and anterior temporalis electromyography (EMG) over 3 days and 3 nights. The duty factor (time of muscle activity/total recording time [%]) was quantified using subject-specific EMG/bite-force calibration via data recorded in the laboratory. Group differences (α = .05) were assessed for psychosocial scores and duty factors using chi-square and two-sample t tests. Linear regression assessed whether psychosocial scores were associated with duty factors. RESULTS Average duty factors were ≤ 2.4% for awake and sleep times in both muscles, and between-group comparisons showed no significant differences. For physical symptom scores, there were significantly fewer TMD-related pain subjects in the normal category and significantly more in the moderate-severe category (all P < .01) compared to controls. Subjects with elevated compared to normal psychosocial scores showed significantly higher jaw muscle duty factors by ≥ 1.5-fold. CONCLUSION A significantly larger proportion of TMD-related pain subjects compared to control subjects had moderate-severe physical symptom scores. Awake- and sleep-time jaw muscle duty factors were not different between groups and were generally low among all subjects. Additionally, higher than normal psychosocial scores were associated with significantly more low-magnitude jaw muscle activity.
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- 2018
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17. Preface to <scp>COAST</scp> 2018 Innovators’ Workshop: Bridging the biology and technology gap in orthodontics and craniofacial care
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David A. Covell, Sarandeep S. Huja, Laura R. Iwasaki, Jeff C. Nickel, Sylvia A. Frazier-Bowers, and Sunil Kapila
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Orthodontics ,Digital work ,Bridging (networking) ,030206 dentistry ,Cone-Beam Computed Tomography ,Technology gap ,Focus group ,Reference plane ,03 medical and health sciences ,Imaging, Three-Dimensional ,0302 clinical medicine ,Otorhinolaryngology ,Surgery ,Relevance (information retrieval) ,030212 general & internal medicine ,Oral Surgery ,Craniofacial ,Craniofacial growth - Abstract
Objective A third focused workshop explored how to transfer novel findings into clinical orthodontic practice. Setting and sample population Participants met at the Scottsdale Plaza Resort, 12-16 September 2018 for the Consortium for Orthodontic Advances in Science and Technology 2018 Innovators' Workshop. Thirty speakers and four lunch-hour focus group leaders shared and exchanged information with approximately 45 registered attendees. Material and methods This Innovators' Workshop was organized according to five themed sessions which covered: (a) The relevance of genetics, biology and environment to therapeutic outcomes; (b) Application of bioinformatics in craniofacial research; (c) Regeneration with and for orthodontic treatment; (d) Technology in precision orthodontics; and (e) Muscle, joint, and airway: Growth, function and pain. Results The papers that comprise this supplemental issue exemplify the important outcomes of the 2018 COAST Workshop. In addition, matters identified as important needs include improved understanding of neural, skeletal and muscle tissue crosstalk in early craniofacial growth; standardized methods for three-dimensional radiographic and surface landmark and reference plane identification, measurements and serial superimpositioning techniques for use in the clinic; sharing and making available existing data sets (eg, cone beam computed tomography images, genotype-phenotype data); evidence of the usefulness and effectiveness of new devices; guidelines of what to measure to characterize the airway; more information about the influences of the soft tissues on craniofacial morphology; and information about effective digital work flows applied to clinical and educational settings. Conclusions Progress in bridging the biology-technology gap has identified new needs for improvements in orthodontics and craniofacial care.
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- 2019
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18. Chorion laeve trophoblasts of preeclamptic fetal membranes: histochemically detectable enzyme activities do not change at a subcellular level
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S Matsubara, T Takayama, R Iwasaki, A Izumi, T Watanabe, and I Sato
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Biology (General) ,QH301-705.5 - Abstract
We examined the subcellular localization of ADPdegrading activity and cytochrome c oxidase (CCO) activity in chorion laeve trophoblasts from term and near term human fetal membranes, and compared them with those from severe preeclamptic fetal membranes. The methods used for the detection of enzyme activities were the lead nitrate method for ADP-degrading activity and the diaminobenzidine method for CCO. Precipitates indicative of ADP-degrading activity were visible on surface microvillous plasma membranes of chorion laeve trophoblasts both from normal and preeclamptic fetal membranes. The intensity and distribution patterns were the same in the normal and preeclamptic subjects. CCO labeling was visible in almost all laeve trophoblastic mitochondria both in normal and preeclamptic cases. Previously, we demonstrated that in preeclamptic villous trophoblasts there were decreases in ADP-degrading activity and the presence of CCO-negative mitochondria, which were proposed to lead to dysfunction of each villous trophoblast, and finally to placental insufficiency in preeclampsia. Reductions or changes in enzyme intensities/distribution patterns, which are characteristic features of preeclamptic villous trophoblasts, were absent in chorion laeve trophoblasts in preeclampsia. These results suggest that in preeclampsia there are no, or at least less severe, abnormalities in the enzyme activities of chorion laeve trophoblasts, compared with villous trophoblasts, as far as enzyme-histochemically detectable enzymes are concerned.
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- 2009
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19. Human amniotic epithelial cells are morphologically homogeneous: enzymehistochemical, tracer, and freeze-substitution fixation study
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R Iwasaki, S Matsubara, T Takizawa, and T Takayama
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Biology (General) ,QH301-705.5 - Abstract
We examined the fine subcellular morphology of human amniotic epithelial cells and attempted to answer the question as to whether amniotic epithelial cells consist of heterogeneous or homogeneous cells, which has long been controversial. Study subjects were fetal membranes from pregnant women (n=18) who abdominally gave birth to healthy infants at term (37.9±0.7 weeks of gestation, mean±sd). The methods employed were transmission electron microscopy, enzymehistochemistry, tracer permeability analysis, and freeze-substitution fixation. The labelings for acid phosphatase, cytochrome c oxidase, and CA++ATPase were seen in the lysosomes, mitochondria, and lateral plasma membranes, respectively. The staining distribution pattern of these three enzymes and the morphology of the organelle highlighted by these enzymehistochemistry did not differ among cells. Freeze-substitution fixation revealed that intercellular spaces in the amniotic epithelial cells were narrower than previously thought, but the tracers (horse radish peroxidase and lanthanum nitrate) fully entered these spaces. There were no variations in the tracer permeability among cells. All cells from freeze-substitution fixation exhibited the same morphological features. From these morphological viewpoints, we conclude that human term amniotic epithelial cells consist of a homogeneous cell population.
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- 2009
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20. MRI Assessment of Cardiac Radioablation Lesion at the Cavotricuspid Isthmus in Mini Pigs
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M. Matsuo, F. Hyodo, K. Hiroshi, R. Iwasaki, T. Mori, N. Takasugi, and S. Nagata
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In vivo magnetic resonance spectroscopy ,Cancer Research ,medicine.medical_specialty ,Cavotricuspid isthmus ,Radiation ,medicine.diagnostic_test ,business.industry ,medicine.medical_treatment ,Magnetic resonance imaging ,Coronary arteries ,Lesion ,Radiation therapy ,medicine.anatomical_structure ,Oncology ,medicine ,Radiology, Nuclear Medicine and imaging ,Histopathology ,medicine.symptom ,business ,Nuclear medicine ,Radiation oncologist - Abstract
PURPOSE/OBJECTIVE(S) Stereotactic body radiotherapy (SBRT) is an emerging non-invasive treatment in the management of cardiac arrhythmias. The purpose of this research is to evaluate the MR imaging in the detection of radioablation lesion at the cavotricuspid isthmus (CTI) in mini pigs. MATERIALS/METHODS Four mini pigs underwent magnetic resonance (MR) evaluation of heart function and invasive electrophysiology assessment using electroanatomical mapping (EAM) before and 3 months after SBRT with single-fraction doses of 25Gy at the CTI. SBRT simulation, planning, and treatments were performed with the use of standard techniques. MR examination, including diffusion-weighted MRI, dynamic Gd-enhanced MRI, MR spectroscopy, and T2-weighted MRI were performed before and 3 months after SBRT, followed by histopathologic examination. One radiation oncologist and one radiologist evaluated the detectability and image quality for the irradiated site. MRI findings of the CTI radioablation lesion was compared to electrophysiology and histopathology findings. RESULTS A total dose of 25 Gy was delivered to the CTI (median volume of 25 cc) in a single procedure according to the radiation therapy oncology group. The mean radiation dose to the heart was 7 Gy. The maximal doses (< 0.05 cc) to the left and right coronary arteries were 14 Gy and 13 Gy, respectively. EAM visualized the irradiated site and confirmed clockwise conduction block across the CTI. Gd-enhanced T1-weighted imaging could only detect the irradiated site. There were no statistical differences in the image quality of the all MR images. CONCLUSION These data demonstrated the feasibility of SBRT for creating conduction block across the CTI in mini pigs. Gd-enhanced T1-weighted imaging was essential in assessing the radioablation lesion.
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- 2021
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21. TMJ energy densities in healthy men and women
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H. Liu, Ying Liu, Luigi M. Gallo, Laura R. Iwasaki, Jeffrey C. Nickel, Michala Markova, and Yoly Gonzalez
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Adult ,Male ,Biomedical Engineering ,Numerical modeling ,Article ,Weight-Bearing ,Young Adult ,03 medical and health sciences ,Joint disease ,Sex Factors ,0302 clinical medicine ,Disc displacement ,stomatognathic system ,Rheumatology ,Temporomandibular Joint Disc ,medicine ,Humans ,Orthopedics and Sports Medicine ,Jaw tracking ,Orthodontics ,Temporomandibular Joint ,business.industry ,030206 dentistry ,Anatomy ,Healthy Volunteers ,Biomechanical Phenomena ,Temporomandibular joint ,stomatognathic diseases ,medicine.anatomical_structure ,Energy density ,Female ,Stress, Mechanical ,business ,030217 neurology & neurosurgery - Abstract
Summary Objective Cartilage fatigue, due to mechanical work, may account for the early development of degenerative joint disease (DJD) in the temporomandibular joint (TMJ), and why women are three times more likely to be afflicted. This study tested for gender differences in mechanical energy densities in women and men with healthy TMJs. Design Eighteen women and eighteen men gave informed consent. Research diagnostic criteria including imaging were used to ensure that subjects' TMJs were normal, without disc displacement or signs of DJD. Numerical modeling determined TMJ loads ( F normal ). Jaw tracking and three-dimensional dynamic stereometry characterized individual-specific data of stress-field dynamic mechanics during 10 symmetrical jaw closing cycles. These data were used to estimate tractional forces ( F traction ). Energy densities were then calculated, where: Energy Density = W/ Q (W = work done or mechanical energy input = F traction *distance of stress-field translation, Q = volume of cartilage). Two-way analysis of variance (ANOVA) and follow-up two-group comparisons tested mean energy densities for ipsilateral and contralateral TMJs in women vs men. Results Mean energy densities ± standard deviations in ipsilateral and contralateral TMJs in women were 9.0 ± 9.7 and 8.4 ± 5.5 mJ/mm 3 , respectively, and were significantly larger ( P = 0.004 and 0.001, respectively) compared to ipsilateral and contralateral TMJs in men, which were 5.6 ± 4.2 and 6.3 ± 4.2 mJ/mm 3 , respectively. Conclusions Energy densities were significantly larger in healthy TMJs of women than men. Larger TMJ energy densities during normal jaw functions could predispose earlier mechanical fatigue of the TMJ disc.
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- 2017
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22. Fluid pressurization and tractional forces during <scp>TMJ</scp> disc loading: A biphasic finite element analysis
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Jeffrey C. Nickel, Yongren Wu, Hai Yao, Feng Wei, T. S. Gonzales, Sarah E. Cisewski, Laura R. Iwasaki, and Xin She
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Male ,Materials science ,Swine ,Finite Element Analysis ,0206 medical engineering ,Aggregate modulus ,Orthodontics ,Strain (injury) ,02 engineering and technology ,Article ,Fe simulation ,Stress (mechanics) ,03 medical and health sciences ,0302 clinical medicine ,stomatognathic system ,Interstitial fluid ,Temporomandibular Joint Disc ,medicine ,Animals ,Composite material ,030206 dentistry ,medicine.disease ,020601 biomedical engineering ,Finite element method ,Biomechanical Phenomena ,Extracellular Matrix ,Temporomandibular joint ,stomatognathic diseases ,medicine.anatomical_structure ,Otorhinolaryngology ,Surgery ,Stress, Mechanical ,Oral Surgery ,Confined compression - Abstract
Structured AbstractObjectives To investigate the ploughing mechanism associated with tractional force formation on the temporomandibular joint (TMJ) disc surface. Setting and Sample Population Ten left TMJ discs were harvested from 6- to 8-month-old male Yorkshire pigs. Materials and Methods Confined compression tests characterized mechanical TMJ disc properties, which were incorporated into a biphasic finite element model (FEM). The FEM was established to investigate load carriage within the extracellular matrix (ECM) and the ploughing mechanism during tractional force formation by simulating previous in vitro plough experiments. Results Biphasic mechanical properties were determined in five TMJ disc regions (average±standard deviation for aggregate modulus: 0.077±0.040 MPa; hydraulic permeability: 0.88±0.37×10−3 mm4/Ns). FE simulation results demonstrated that interstitial fluid pressurization is a dominant loading support mechanism in the TMJ disc. Increased contact load and duration led to increased solid ECM strain and stress within, and increased ploughing force on the surface of the disc. Conclusion Sustained mechanical loading may play a role in load carriage within the ECM and ploughing force formation during stress-field translation at the condyle–disc interface. This study further elucidated the mechanism of ploughing on tractional force formation and provided a baseline for future analysis of TMJ mechanics, cartilage fatigue and early TMJ degeneration.
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- 2017
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23. A pilot study of nocturnal temporalis muscle activity in TMD diagnostic groups of women
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L. R. Iwasaki, J. C. Nickel, Hai Yao, J. M. Scott, Yoly Gonzalez, Xin She, M. H. Van Horn, Matthew C. Coombs, Feng Wei, and T. S. Gonzales
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Adult ,Polysomnography ,Monitoring, Ambulatory ,Sleep Bruxism ,Dentistry ,Pilot Projects ,Temporal Muscle ,Electromyography ,Temporalis muscle ,Nocturnal ,Article ,Bite Force ,Adult women ,03 medical and health sciences ,0302 clinical medicine ,Humans ,Medicine ,Muscle activity ,General Dentistry ,Orthodontics ,Missouri ,medicine.diagnostic_test ,Masseter Muscle ,business.industry ,030206 dentistry ,Middle Aged ,Temporomandibular Joint Disorders ,Bite force quotient ,Ambulatory ,Female ,Chronic Pain ,Sleep ,business ,Algorithms ,030217 neurology & neurosurgery ,Muscle Contraction - Abstract
Temporomandibular disorder (TMD) incidences are believed to be related to parafunctional behaviours like teeth clenching. This pilot study aimed to (i) develop an automated clench-detection algorithm, and (ii) apply the algorithm to test for differences in nocturnal clenching in women with and without TMD. Subjects gave informed consent to participate. Adult women were categorised using Diagnostic Criteria for TMD according to presence/absence (+/-) of both TM joint disc placement (DD) and chronic pain (P) into two groups (+DD+P, -DD-P) with 12 subjects each. Surface temporalis electromyography was recorded during oral tasks performed by subjects at two laboratory sessions. The data were used to characterise muscle activity per N of bite force (μV/N) for each subject, develop the clench-detection algorithm and test its accuracy. Ambulatory surface temporalis electromyography was self-recorded by each subject over three nights and analysed using the algorithm and bite force (N) versus muscle activity μV/N calibrations. Bonferroni-adjusted homoscedastic t-tests assessed for significant between-group differences in clenching (P < 0·05). Sensitivity, specificity and accuracy of algorithm-detected laboratory clenches were all ≥96%. During self-recordings 95% of clenches had durations of
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- 2017
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24. Noninvasive Redox Imaging of Tumor Redox Status for Early Detection of Radiation Response using In Vivo DNP-MRI
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R. Iwasaki, Fuminori Hyodo, Masayuki Matsuo, H. Tomita, T. Masaki, S. Shoda, N. Koyasu, and Tadashi Mori
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Cancer Research ,Radiation ,Oncology ,In vivo ,business.industry ,Cancer research ,Early detection ,Medicine ,Radiology, Nuclear Medicine and imaging ,business ,Redox status ,Redox ,Radiation response - Published
- 2020
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25. Visualization of Free Radical Generation Induced by Radiation using Dynamic Nuclear Polarization-MRI
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Masayuki Matsuo, F. Hyodo, Tadashi Mori, R. Iwasaki, N. Koyasu, and Takahiro Yamaguchi
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Cancer Research ,Radiation ,Optics ,Oncology ,business.industry ,Medicine ,Radiology, Nuclear Medicine and imaging ,business ,Polarization (waves) ,Visualization - Published
- 2020
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26. Opinions, plans, and demographics of orthodontic residents: A follow-up study
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Eli Schwarz, Laura R. Iwasaki, Amelia C. Stoker, and Larry Doyle
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medicine.medical_specialty ,Demographics ,MEDLINE ,Specialty ,Follow up studies ,Survey tool ,Internship and Residency ,Orthodontics ,030206 dentistry ,03 medical and health sciences ,0302 clinical medicine ,Family medicine ,Surveys and Questionnaires ,medicine ,Female ,Psychology ,030217 neurology & neurosurgery ,Demography ,Follow-Up Studies - Abstract
This study aimed to explore current orthodontic residents' demographics, their opinions on their residency and plans for the future and highlight secular changes since past surveys.An anonymous 39-item institutional review board-approved survey was implemented at the 2018 Graduate Orthodontic Resident Program using an online survey tool and portable devices. Questions fit 3 categories: program, future goals, and demographics. Responses were analyzed to determine frequencies, means, and cross tabulations. Analyses of variance and chi-square were applied with significance defined as P 0.05.Of the 489 attendees, 76% completed the survey; most were female (51%), white (60%), U.S. citizens (85%), single (63%), and very satisfied with their programs (54%). Tuition costs varied, but 18% of respondents paid $80,000 annually. Orthodontic and total educational debts were significantly correlated (r = 0.704) and averaged $137,706 ± $127,380 and $323,071 ± $266,510, respectively. These debts were significantly lower (P 0.0001) for respondents with stipends. Debts influenced the decision of where to work in the future for 62% of respondents and were a source of anxiety for 72% of respondents. Educational debts were significantly positively associated with anxiety levels (P 0.0001).This survey provided current information on orthodontic residents' opinions, plans, and demographics. Comparisons with previous surveys showed increases in the number of female respondents, tuition costs, and educational debts and decreases in stipends. Orthodontics may be approaching a "bubble market" where the financial benefits do not outweigh specialty education costs.
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- 2019
27. Effect of Sustained Joint Loading on TMJ Disc Nutrient Environment
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Feng Wei, Sarah E. Cisewski, M H Brown, Xin She, Matthew C. Coombs, Vera Colombo, Hai Yao, Yoly Gonzalez, Yongren Wu, J.C. Nickel, Luigi M. Gallo, Michael J. Kern, Laura R. Iwasaki, University of Zurich, and Yao, H
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Adult ,Male ,Swine ,Energy metabolism ,610 Medicine & health ,Diffusion ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Nutrient ,stomatognathic system ,In vivo ,Temporomandibular Joint Disc ,medicine ,Animals ,Humans ,Lactic Acid ,General Dentistry ,Joint loading ,Chemistry ,10223 Clinic for Masticatory Disorders ,Research Reports ,030206 dentistry ,Nutrients ,3500 General Dentistry ,Temporomandibular joint ,Biomechanical Phenomena ,Oxygen ,stomatognathic diseases ,medicine.anatomical_structure ,Glucose ,Solute diffusion ,Limiting oxygen concentration ,Stress, Mechanical ,Fe model ,Energy Metabolism ,030217 neurology & neurosurgery ,Biomedical engineering - Abstract
The temporomandibular joint (TMJ) disc nutrient environment profoundly affects cell energy metabolism, proliferation, and biosynthesis. Due to technical challenges of in vivo measurements, the human TMJ disc extracellular nutrient environment under load, which depends on metabolic rates, solute diffusion, and disc morphometry, remains unknown. Therefore, the study objective was to predict the TMJ disc nutrient environment under loading conditions using combined experimental and computational modeling approaches. Specifically, glucose consumption and lactate production rates of porcine TMJ discs were measured under varying tissue culture conditions ( n = 40 discs), and mechanical strain-dependent glucose and lactate diffusivities were measured using a custom diffusion chamber ( n = 6 discs). TMJ anatomy and loading area were obtained from magnetic resonance imaging of healthy human volunteers ( n = 11, male, 30 ± 9 y). Using experimentally determined nutrient metabolic rates, solute diffusivities, TMJ anatomy, and loading areas, subject-specific finite element (FE) models were developed to predict the 3-dimensional nutrient profiles in unloaded and loaded TMJ discs (unloaded, 0% strain, 20% strain). From the FE models, glucose, lactate, and oxygen concentration ranges for unloaded healthy human TMJ discs were 0.6 to 4.0 mM, 0.9 to 5.0 mM, and 0% to 6%, respectively, with steep gradients in the anterior and posterior bands. Sustained mechanical loading significantly reduced nutrient levels ( P < 0.001), with a critical zone in which cells may die representing approximately 13.5% of the total disc volume. In conclusion, this study experimentally determined TMJ disc metabolic rates, solute diffusivities, and disc morphometry, and through subject-specific FE modeling, revealed critical interactions between mechanical loading and nutrient supply and metabolism for the in vivo human TMJ disc. The results suggest that TMJ disc homeostasis may be vulnerable to pathological loading (e.g., clenching, bruxism), which impedes nutrient supply. Given difficulties associated with direct in vivo measurements, this study provides a new approach to systematically investigate homeostatic and degenerative mechanisms associated with the TMJ disc.
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- 2019
28. Development of Lambertson Magnet and Septum Magnets for Splitting 30-GeV Proton Beam in Hadron Experimental Facility at J-PARC
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Yuhei Morino, Yutaka Yamanoi, Michifumi Minakawa, Erina Hirose, Kazuhiro Tanaka, Kazuya Aoki, Yoshihiro Suzuki, Y. Katoh, Keizo Agari, Yoshinori Sato, Akihisa Toyoda, Yoshihisa Shirakabe, Hiroaki Watanabe, Kyoichiro Ozawa, Hitoshi Takahashi, S. Sawada, R. Iwasaki, Masaharu Ieiri, Y. Fukao, and Ryotaro Muto
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Physics ,Proton ,Superconducting magnet ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Magnetic field ,Nuclear physics ,Beamline ,Dipole magnet ,Magnet ,0103 physical sciences ,Physics::Accelerator Physics ,J-PARC ,Electrical and Electronic Engineering ,Nuclear Experiment ,010306 general physics ,Beam (structure) - Abstract
We developed a Lambertson magnet and two septum magnets as the splitting devices for the new beamline at the Hadron Experimental Facility in J-PARC. This new beamline, now under construction, is called high-p/COMET beamline, and the experiments using 30- and 8-GeV proton beams are planned. The required functions of the splitting devices are as follows: to split a small fraction (around 10−4) of the 30-GeV proton beam into the high-p/COMET beamline (30-GeV mode) and to bend all of the 8-GeV proton beam into the high-p/COMET beamline (8-GeV mode). These two requirements are met by adjusting the vertical beam position at the entrance of the Lambertson magnet. In 30-GeV mode, the Lambertson magnet is used to scrape the beam halo of the proton beam and bend the beam into the high-p/COMET beamline. The beam loss at the Lambertson magnet is inevitable; thus, the magnet must be resistant to the radiation and heat caused by the beam loss. The magnet is composed of nonorganic materials only and equipped with two water pipes to remove the heat induced by the beam loss. The branched beam is bent further by two septum magnets at the downstream of the Lambertson magnet. The construction and the magnetic field measurements of these devices were completed in March 2015, and the installation into the beamline is planned for the summer of year 2017.
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- 2016
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29. Preface to COAST 2016 innovators’ workshop on personalized and precision orthodontic therapy
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Sarandeep S. Huja, Sylvia A. Frazier-Bowers, Jeffrey C. Nickel, Laura R. Iwasaki, David A. Covell, and Sunil Kapila
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Orthodontics ,Medical education ,Emerging technologies ,Myofascial pain ,030206 dentistry ,Focus group ,Mandibular growth ,03 medical and health sciences ,0302 clinical medicine ,Otorhinolaryngology ,Surgery ,Bone biology ,Oral Surgery ,Psychology ,030217 neurology & neurosurgery - Abstract
OBJECTIVE A second focused workshop explored how to transfer novel findings into clinical orthodontic practice. SETTING AND SAMPLE POPULATION Participants met in West Palm Beach (Florida, USA), on 9-11 September 2016 for the Consortium for Orthodontic Advances in Science and Technology 2016 Innovators' Workshop (COAST). Approximately 65 registered attendees considered and discussed information from 27 to 34 speakers, 8 to 15 poster presenters and four lunch-hour focus group leaders. MATERIAL AND METHODS The innovators' workshops were organized according to five themed sessions. The aims of the discussion sessions were to identify the following: i) the strength and impact of the evidenced-based discoveries, ii) required steps to enable further development and iii) required steps to translate these new discoveries into orthodontic practice. RESULTS The role of gene-environment interactions that underlie complex craniofacial traits was the focus of several sessions. It was agreed that diverse approaches are called for, such as (i) large-scale collaborative efforts for future genetic studies of complex traits; (ii) deep genome sequencing to address the issues of isolated mutations; (iii) quantifying epigenetic-environmental variables in diverse areas myofascial pain, alveolar remodelling and mandibular growth. Common needs identified from the themed sessions were multiscale/multispecies modelling and experimentation using controlled and quantified mechanics and translation of the findings in bone biology between species. Panel discussions led to the consensus that a consortium approach to establish standards for intra-oral scanning and 3D imaging should be initiated. CONCLUSIONS Current and emerging technologies still require supported research to translate new findings from the laboratory to orthodontic practice.
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- 2017
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30. Activation of the Wnt/β-Catenin Signaling Pathway Causes Radioresistance in Colon Cancer
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H. Takano, Fuminori Hyodo, Hidekazu Tanaka, Masaya Kawaguchi, Toshiharu Miyoshi, H. Tomita, R. Iwasaki, A. Hara, Takayuki Mori, S. Shoda, and Masayuki Matsuo
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Cancer Research ,Radiation ,Oncology ,Colorectal cancer ,business.industry ,Radioresistance ,medicine ,Cancer research ,Wnt β catenin signaling ,Radiology, Nuclear Medicine and imaging ,medicine.disease ,business - Published
- 2019
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31. Modeling of muscle forces in humans with and without temporomandibular joint disorders
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H. Liu, Yoly Gonzalez, David B. Marx, Laura R. Iwasaki, and Jeffrey C. Nickel
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Male ,musculoskeletal diseases ,genetic structures ,Joint Dislocations ,Temporal Muscle ,Orthodontics ,Models, Biological ,Article ,Bite Force ,stomatognathic system ,Temporomandibular Joint Disc ,Humans ,Medicine ,Computer Simulation ,Masseter Muscle ,business.industry ,Biomechanics ,Pterygoid Muscles ,Temporomandibular Joint Disorders ,Temporomandibular Joint Dysfunction Syndrome ,Magnetic Resonance Imaging ,Molar ,Biomechanical Phenomena ,Temporomandibular joint ,Incisor ,stomatognathic diseases ,medicine.anatomical_structure ,Otorhinolaryngology ,Masticatory Muscles ,Female ,Surgery ,Stress, Mechanical ,Oral Surgery ,Tomography, X-Ray Computed ,business - Abstract
Subjects with/without temporomandibular joint disorders (TMJD) were tested for differences in muscle forces.School of Dental Medicine, University at Buffalo. Ninety-one subjects were classified in four groups based on the presence/absence (±) of chronic myofascial and/or TMJ pain (P) and bilateral disc displacement (DD).Validated numerical models employed an organizational objective and subjects' anatomy to calculate masticatory muscle forces during static biting. anova and Holm's step-down procedure post hoc tests assessed group differences. Theoretical geometries, representing the range of subjects' muscle orientations, were surveyed via numerical models to identify key combinations resulting in high muscle forces. Effect size (Cohen's d) and anova/post hoc tests assessed group differences in key muscle orientations.+P-DD subjects had significantly higher muscle forces, especially for lateral pterygoid muscles, compared to the other groups (p0.01) for bite forces that were directed posteromedially or posterolaterally on mandibular molars and posteriorly and slightly medially on mandibular incisors. Key muscle orientations for peak lateral pterygoid muscle forces were identified, and group comparisons showed mean orientation in +P-DD compared to other diagnostic groups was ≥5° more upright for masseter and ≥3° more posteriorly directed for temporalis muscles (all Cohen's d≥0.8).Predicted lateral pterygoid muscle forces were significantly higher in +P-DD compared to other groups for specific biting conditions and were attributable, in part, to differences in masseter and temporalis muscle orientations.
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- 2015
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32. Diagnostic group differences in temporomandibular joint energy densities
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David B. Marx, H. Liu, Yoly Gonzalez, Jeffrey C. Nickel, Luigi M. Gallo, and Laura R. Iwasaki
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Adult ,Cartilage, Articular ,Male ,Work ,Joint Dislocations ,Orthodontics ,Models, Biological ,Article ,Facial Pain ,Temporomandibular Joint Disc ,Image Processing, Computer-Assisted ,medicine ,Humans ,Computer Simulation ,Joint dislocation ,Range of Motion, Articular ,Mechanical energy ,medicine.diagnostic_test ,business.industry ,Magnetic resonance imaging ,Anatomy ,Cone-Beam Computed Tomography ,Temporomandibular Joint Disorders ,Temporomandibular Joint Dysfunction Syndrome ,medicine.disease ,Arthralgia ,Magnetic Resonance Imaging ,Biomechanical Phenomena ,Temporomandibular joint ,medicine.anatomical_structure ,Standard error ,Otorhinolaryngology ,Joint pain ,Female ,Surgery ,Stress, Mechanical ,Oral Surgery ,medicine.symptom ,business ,Nuclear medicine - Abstract
OBJECTIVES Cartilage fatigue, due to mechanical work, may account for precocious development of degenerative joint disease in the temporomandibular joint (TMJ). This study compared energy densities (mJ/mm³) in TMJs of three diagnostic groups. SETTING AND SAMPLE POPULATION Sixty-eight subjects (44 women, 24 men) gave informed consent. Diagnostic criteria for temporomandibular disorders (DC/TMD) and imaging were used to group subjects according to presence of jaw muscle or joint pain (+P) and bilateral disk displacement (+DD). MATERIAL AND METHODS Subjects (+P+DD, n = 16; -P+DD, n = 16; and -P-DD, n = 36) provided cone-beam computed tomography and magnetic resonance images, and jaw-tracking data. Numerical modeling was used to determine TMJ loads (Fnormal ). Dynamic stereometry was used to characterize individual-specific data of stress-field dynamics during 10 symmetrical jaw-closing cycles. These data were used to estimate tractional forces (Ftraction ). Energy densities were then calculated as W/Q (W = work done or mechanical energy input=tractional force × distance of stress-field translation, Q = volume of cartilage). anova and Tukey-Kramer post hoc analyses tested for intergroup differences. RESULTS Mean ± standard error energy density for the +P+DD group was 12.7 ± 1.5 mJ/mm³ and significantly greater (all adjusted p < 0.04) when compared to -P+DD (7.4 ± 1.4 mJ/mm³) and -P-DD (5.8 ± 0.9 mJ/mm³) groups. Energy densities in -P+DD and -P-DD groups were not significantly different. CONCLUSION Diagnostic group differences in energy densities suggest that mechanical work may be a unique mechanism, which contributes to cartilage fatigue in subjects with pain and disk displacement.
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- 2015
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33. Infield masticatory muscle activity in subjects with pain-related temporomandibular disorders diagnoses
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Heidi C. Crow, Shehryar N. Khawaja, W.D. McCall, Yoly Gonzalez, Jeffrey C. Nickel, Robert G. Dunford, and Laura R. Iwasaki
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Adult ,Male ,myalgia ,medicine.medical_specialty ,Transducers ,Monitoring, Ambulatory ,Temporal Muscle ,Orthodontics ,Electromyography ,Temporal muscle ,Article ,Bite Force ,Masseter muscle ,Young Adult ,Physical medicine and rehabilitation ,Facial Pain ,Humans ,Medicine ,Wakefulness ,Young adult ,Medical diagnosis ,medicine.diagnostic_test ,Masseter Muscle ,business.industry ,Muscle Tonus ,food and beverages ,Myalgia ,Middle Aged ,Temporomandibular Joint Disorders ,Arthralgia ,stomatognathic diseases ,Otorhinolaryngology ,Female ,Surgery ,Oral Surgery ,medicine.symptom ,Sleep ,business ,human activities ,Masticatory muscle - Abstract
Pain-related temporomandibular disorders (TMDs) are the most prevalent conditions among TMDs. There is contrasting evidence available for association of pain-related TMD and masticatory muscle activity (MMA). The present investigation assesses the associations between MMA levels of masseter and temporalis muscles during awake and sleep among pain-related TMD diagnostic groups.The department of Oral Diagnostic Sciences, University at Buffalo. Twenty females and six males participated in this study.Using the diagnostic criteria for temporomandibular disorders (DC-TMDs), participants were diagnostically categorized. Subjects used a custom monitoring system, which recorded infield muscle activities. A factorial model tested for association between independent variable (muscle, time period, MMA level, and diagnostic group) effects and the logarithm of MMA. Greenhouse-Geisser test was used to determine any statistically significant associations (p≤0.003).No statistically significant association was found between four-way, three-way, and two-way analyses. However, among the main effects, range of magnitudes was the only variable to be statistically significant. Although the data suggest a trend of increased masseter MMA in the pain-related TMD diagnoses group both during awake and sleep time periods, such observation is not maintained for the temporalis muscle. In addition, temporalis MMA was found to be higher in the pain-related TMD diagnoses group only at extreme activity levels (25 and ≥80% ranges).This data support the association between masticatory muscle hyperactivity and painful TMD conditions.
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- 2015
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34. Personalized and precision orthodontic therapy
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Sunil Kapila, Sarandeep S. Huja, Jeffrey C. Nickel, Laura R. Iwasaki, David A. Covell, and Sylvia A. Frazier-Bowers
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Diagnostic Imaging ,medicine.medical_specialty ,Emerging technologies ,Dental Research ,Alternative medicine ,Orthodontics ,Orthodontics, Corrective ,Body of knowledge ,Strength of evidence ,Technology Transfer ,medicine ,Humans ,Computer Simulation ,Bone biology ,Precision Medicine ,Medical education ,Tissue Engineering ,Genome, Human ,business.industry ,Congresses as Topic ,Biomechanical Phenomena ,Clinical Practice ,Otorhinolaryngology ,Private practice ,Technology, Dental ,Surgery ,Diffusion of Innovation ,Oral Surgery ,business - Abstract
Structured Abstract Objective To bring together orthodontic stakeholders from academics, industry, and private practice for a series of thematically focused workshops to explore and develop the transfer of novel approaches into clinical orthodontic practice. Setting and sample population Twenty-seven invited speakers, eight poster presenters, and participants of the Consortium for Orthodontic Advances in Science and Technology (COAST) 2014 Innovators' Workshop at the Eaglewood Resort and Spa, Itasca, Illinois, September 11–14, 2014. Material and methods Five themed sessions involving between 4–7 presentations followed by panel discussions were organized. The aims of the discussion sessions were to highlight important findings and consider the strength of evidence for these, indicate next steps and needed research or technological developments to move forward, and to weigh the expected benefits from these findings and steps to implement in clinical practice. Results Among important areas for attention identified were need for multiscale and multispecies modeling and experimentation for interspecies translation of results; large-scale collaborative efforts within the profession to address the need for adequate sample sizes for future genetic studies of complex traits such as malocclusion; a consortium approach to improve new technologies such as intra-oral scanning and 3D imaging by establishing standards; and harnessing the growing body of knowledge about bone biology for application in orthodontics. Conclusions With increased awareness of the potential of current and emerging technologies, translation of personalized and precision approaches in the field of orthodontics holds ever-increasing promise.
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- 2015
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35. Prevalence differentiations of periodontitis by diabetic status among US adults
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Ying Liu, Ronghai Bie, Laura R. Iwasaki, and Jeffrey C. Nickel
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Adult ,Male ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,MEDLINE ,030209 endocrinology & metabolism ,03 medical and health sciences ,0302 clinical medicine ,Periodontal disease ,Internal medicine ,Diabetes mellitus ,medicine ,Diabetes Mellitus ,Prevalence ,Humans ,Periodontitis ,business.industry ,Follow up studies ,030206 dentistry ,Middle Aged ,medicine.disease ,Prognosis ,United States ,Female ,business ,Follow-Up Studies - Published
- 2018
36. Jaw closing movement and sex differences in temporomandibular joint energy densities
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Jeffrey C. Nickel, Ying Liu, Luigi M. Gallo, H. Liu, Laura R. Iwasaki, Yoly Gonzalez, and Nicolas Fankhauser
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Adult ,Male ,0206 medical engineering ,Computed tomography ,Temporal Muscle ,02 engineering and technology ,Article ,Bite Force ,03 medical and health sciences ,0302 clinical medicine ,stomatognathic system ,medicine ,Image Processing, Computer-Assisted ,Humans ,Closing (morphology) ,General Dentistry ,Orthodontics ,Sex Characteristics ,medicine.diagnostic_test ,Temporomandibular Joint ,business.industry ,Masseter Muscle ,Magnetic resonance imaging ,030206 dentistry ,020601 biomedical engineering ,Mr imaging ,Magnetic Resonance Imaging ,Healthy Volunteers ,Temporomandibular joint ,Biomechanical Phenomena ,stomatognathic diseases ,Observational Studies as Topic ,Biting ,medicine.anatomical_structure ,Cross-Sectional Studies ,Healthy individuals ,Female ,Stress, Mechanical ,business - Abstract
Energy densities (ED, mJ/mm3) quantify mechanical work imposed on articular cartilages during function. This cross-sectional study examined differences in temporomandibular joint (TMJ) ED during asymmetric versus symmetric jaw closing in healthy females versus males. ED component variables were tested for differences between and within sexes for two types of jaw closing. Seventeen female and 17 male subjects gave informed consent to participate. Diagnostic Criteria for Temporomandibular Disorders and images (magnetic resonance (MR), computed tomography) were used to confirm healthy TMJ status. Numerical modeling predicted TMJ loads (Fnormal) consequent to unilateral canine biting. Dynamic stereometry combined MR imaging and jaw tracking data to measure ED component variables during 10 trials of each type of jaw closing in each subject’s TMJs. These data were then used to calculate TMJ ED during jaw closing asymmetrically and symmetrically. Paired and Student’s t-tests assessed ED between jaw closing movements and sexes, respectively. Multivariate data analyses assessed ED component variable differences between jaw closing movements and sexes (α=0.05). Contralateral TMJ ED were 3.6-fold and significantly larger (P
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- 2017
37. Disposable aptamer-sensor aided by magnetic nanoparticle enrichment for detection of salivary cortisol variations in obstructive sleep apnea patients
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Burt K. Kawamoto, Yogeswaran Umasankar, Shekhar Bhansali, JoAnna M. Scott, Pandiaraj Manickam, Jeffrey C. Nickel, Renny Edwin Fernandez, Laura R. Iwasaki, and Kristen C. Todoki
- Subjects
Adult ,Male ,Hydrocortisone ,Aptamer ,Point-of-Care Systems ,High selectivity ,Nanoparticle ,lcsh:Medicine ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Article ,Magnetite Nanoparticles ,medicine ,Humans ,Salvia ,lcsh:Science ,Disposable Equipment ,Electrodes ,Salivary cortisol ,Sleep Apnea, Obstructive ,Multidisciplinary ,Chemistry ,lcsh:R ,Sleep apnea ,Middle Aged ,021001 nanoscience & nanotechnology ,medicine.disease ,equipment and supplies ,0104 chemical sciences ,Obstructive sleep apnea ,Magnetic nanoparticles ,lcsh:Q ,Female ,0210 nano-technology ,human activities ,hormones, hormone substitutes, and hormone antagonists ,Biomedical engineering - Abstract
We report a disposable point-of-care sensing platform specific to salivary cortisol detection. The sensor is inkjet printed on a paper substrate with a metalloporphyrin based macrocyclic catalyst ink that can electrochemically reduce cortisol, captured by aptamer functionalized magnetic nanoparticles. The sensor consists of a thin magnet disc, aligned at the back of the electrode, in order to populate the magnetic nanoparticle bound cortisol at the sensing electrode area. Proof of concept studies were performed to detect salivary cortisol levels in human subjects with high and low risks for obstructive sleep apnea (OSA). High selectivity was observed to salivary cortisol against a background of closely related steroids.
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- 2017
38. Mechanobehavioral Scores in Women with and without TMJ Disc Displacement
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H. Liu, Jeffrey C. Nickel, Yoly Gonzalez, Laura R. Iwasaki, Ying Liu, Luigi M. Gallo, and Michala Markova
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Adult ,0206 medical engineering ,Dentistry ,Computed tomography ,Temporal Muscle ,02 engineering and technology ,Electromyography ,Bite Force ,03 medical and health sciences ,0302 clinical medicine ,Disc displacement ,stomatognathic system ,Temporomandibular Joint Disc ,medicine ,Humans ,General Dentistry ,Orthodontics ,medicine.diagnostic_test ,business.industry ,Masseter Muscle ,Cartilage ,Magnetic resonance imaging ,Research Reports ,030206 dentistry ,Temporomandibular Joint Disorders ,020601 biomedical engineering ,Temporomandibular joint ,Biomechanical Phenomena ,Jaw muscle ,stomatognathic diseases ,medicine.anatomical_structure ,Cross-Sectional Studies ,Case-Control Studies ,Female ,Mr images ,business - Abstract
Cartilage fatigue may be a factor in the precocious development of degenerative changes in the temporomandibular joint (TMJ). This cross-sectional study estimated potential for cartilage fatigue via TMJ energy densities (ED) and jaw muscle duty factors (DF), which were combined to calculate mechanobehavioral scores (MBS) in women with (+) and without (–) bilateral TMJ disc displacement (DD). All subjects gave informed consent to participate and were examined using Diagnostic Criteria (DC) for Temporomandibular Disorders (TMD) and magnetic resonance (MR) and computed tomography (CT) images. Forty-seven subjects were categorized into +DD ( n = 29) and –DD ( n = 18) groups. Dynamic stereometry (MR images combined with jaw-tracking data) characterized individual-specific data of TMJ stress-field mechanics to determine ED (ED = W/ Q mJ/mm3, where W = work done, Q = volume of cartilage) during 10 symmetrical jaw-closing cycles with a 20-N mandibular right canine load. Subjects were trained to record masseter and temporalis electromyography over 3 days and 3 nights. Root mean square electromyography/bite-force calibrations determined subject-specific masseter and temporalis muscle activities per 20-N bite-force (T20 N, µV), which defined thresholds. Muscle DF (DF = % duration of muscle activity/total recording time) were determined for a range of thresholds, and MBS (ED2 × DF) were calculated. Intergroup differences in ED, DF, and MBS were assessed via analyses of variance with Bonferroni and Tukey honest significant difference post hoc tests. Average ED for contralateral TMJs was significantly larger ( P = 0.012) by 1.4-fold in +DD compared to –DD subjects. Average DF were significantly larger (all P < 0.01) for +DD compared to –DD subjects by 1.7-, 2.5-, and 1.9-fold for day, night, and overall, respectively. Daytime MBS were significantly larger (all P < 0.04) by up to 8.5-fold in +DD compared to –DD subjects. Significantly larger ED, DF, and MBS were shown in women with compared to women without bilateral TMJ DD.
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- 2017
39. Jaw mechanics in dolichofacial and brachyfacial phenotypes: A longitudinal cephalometric-based study
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H. Liu, Laura R. Iwasaki, Jeffrey C. Nickel, and Y. Liu
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Molar ,Male ,Adolescent ,Cephalometry ,Dentistry ,Orthodontics ,Mandible ,01 natural sciences ,Bite Force ,03 medical and health sciences ,0302 clinical medicine ,stomatognathic system ,Statistical significance ,0103 physical sciences ,Medicine ,Humans ,Longitudinal Studies ,Craniofacial ,Child ,010301 acoustics ,Temporomandibular Joint ,business.industry ,030206 dentistry ,Mechanics ,Craniometry ,Temporomandibular joint ,Biomechanical Phenomena ,Bite force quotient ,stomatognathic diseases ,Biting ,medicine.anatomical_structure ,Phenotype ,Otorhinolaryngology ,Face ,Surgery ,Female ,Oral Surgery ,business - Abstract
OBJECTIVES To determine whether dolichofacial (Frankfort horizontal mandibular plane angle (FHMPA) ≥30°) vs brachyfacial (FHMPA ≤22°) phenotypes differ in temporomandibular joint (TMJ) loads and whether these differences correlate longitudinally with mandibular ramus height (Condylion-Gonion, Co-Go). SETTING AND SAMPLE POPULATION Lateral and posteroanterior cephalographs from ten dolichofacial and ten brachyfacial individuals made at average ages of 6 (T1), 12 (T2) and 18 (T3) years and available online (http://www.aaoflegacycollection.org/aaof_home.html) were used. MATERIALS AND METHODS Three-dimensional anatomical data were derived from cephalographs and used in numerical models to predict TMJ loads for a range of biting angles on incisors, canines and first molars. Two criteria were used to define clinically important between-group TMJ load differences: statistical significance was defined with a two-group t-test, and where differences were also ≥20%. A statistical approach called response surface analysis was used to assess correlation between TMJ loads and its predictors considered in this study. RESULTS The two phenotypes had significantly different FHMPA at all ages (P
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- 2017
40. Speed of human tooth movement in growers and non-growers: Selection of applied stress matters
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Laura R. Iwasaki, Jeffrey C. Nickel, Y. Liu, and H. Liu
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Dental Stress Analysis ,Male ,Cuspid ,Time Factors ,Adolescent ,Tooth Movement Techniques ,Cephalometry ,Dentistry ,Orthodontics ,Maxillary first premolar ,Stress (mechanics) ,03 medical and health sciences ,Young Adult ,0302 clinical medicine ,Human tooth ,Statistical analyses ,medicine ,Alloys ,Maxilla ,Orthodontic Wires ,Humans ,Orthodontic Appliance Design ,Mathematics ,business.industry ,Significant difference ,Maxillary canine ,030206 dentistry ,medicine.anatomical_structure ,Otorhinolaryngology ,Tooth movement ,Tooth Extraction ,Surgery ,Female ,Stress, Mechanical ,Oral Surgery ,business ,030217 neurology & neurosurgery - Abstract
Objectives To test that the speed of tooth translation is not affected by stress magnitude and growth status. Setting and sample population Advanced Education Orthodontic clinics at the Universities of Nebraska Medical Center and Missouri-Kansas City. Forty-six consenting subjects with orthodontic treatment plans involving maxillary first premolar extractions. Materials and methods This randomized split-mouth study used segmental mechanics with definitive posterior anchorage and individual vertical-loop maxillary canine retraction appliances and measured three-dimensional tooth movements. Height and cephalometric superimposition changes determined growing (G) and non-growing (NG) subjects. Subjects were appointed for 9-11 visits over 84 days for maxillary dental impressions to measure three-dimensional tooth movement and to ensure retraction forces were continuously applied via calibrated nitinol coil springs. Springs were custom selected to apply two different stresses of 4, 13, 26, 52 or 78 kPa to maxillary canines in each subject. Statistical analyses (α=0.050) included ANOVA, effect size (partial η2 ) and Tukey's Honest Significant Difference (HSD) and two-group t tests. Results Distolateral translation speeds were 0.034±0.015, 0.047±0.019, 0.066±0.025, 0.068±0.016 and 0.079±0.030 mm/d for 4, 13, 26, 52 and 78 kPa, respectively. Stress significantly affected speed and partial η2 =0.376. Overall, more distopalatal rotation was shown by teeth moved by 78 kPa (18.03±9.50o) compared to other stresses (3.86±6.83o), and speeds were significantly higher (P=.001) in G (0.062±0.026 mm/d) than NG subjects (0.041±0.019 mm/d). Conclusions Stress magnitude and growth status significantly affected the speed of tooth translation. Optimal applied stresses were 26-52 kPa, and overall speeds were 1.5-fold faster in G compared to NG subjects.
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- 2017
41. Fatigue Crack Thresholds Significantly Affected by Thermo-Mechanical Loading Histories in an Austenitic and a Ferritic Low Alloy Steel
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R. Iwasaki, Milton Muzvidziwa, Masakazu Okazaki, and Naoto Kasahara
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Austenite ,Structural material ,Materials science ,Alloy steel ,Metallurgy ,technology, industry, and agriculture ,General Engineering ,Fatigue testing ,Welding ,engineering.material ,Fatigue limit ,law.invention ,Crack closure ,law ,engineering ,Austenitic stainless steel - Abstract
High cycle thermal fatigue failure of pipes induced by fluid temperature change is one of interdisciplinary issues to be concerned for long term structural reliability of high temperature structural material and components in energy systems. In order to get basic understanding on this article. the fatigue crack propagation tests were carried out in a low alloy steel and an austenitic stainless steel those were subjected to typical kinds of thermo-mechanical loading histories those included a simulated weld repair process. It was shown experimentally that the thermo-mechanical histories left their individual effects along the prior fatigue crack wake, resulting in significant change in the fatigue crack threshold. Some proposes are presented to predict those history effects.
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- 2014
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42. Free Radical Imaging for Visualization of Radiation Treatment Using Dynamic Nuclear Polarization (DNP) MRI
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K. Koyasu, Masayuki Matsuo, T. Yamaguchi, Hidekazu Tanaka, S. Shoda, Fuminori Hyodo, M. Takasu, R. Iwasaki, and Tadashi Mori
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Cancer Research ,Radiation ,Nuclear magnetic resonance ,Oncology ,business.industry ,Medicine ,Radiology, Nuclear Medicine and imaging ,Polarization (waves) ,business ,Visualization - Published
- 2019
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43. Mechanical Response of the Porcine Temporomandibular Joint Disc to an Impact Event and Repeated Tensile Loading.
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Mark W. Beatty, Jeffrey C. Nickel, Laura R. Iwasaki, and Mark Leiker
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TEMPOROMANDIBULAR joint injuries ,ANIMAL models in research ,CARTILAGE ,VISCOELASTICITY ,CYCLIC loads ,BIOMECHANICS ,EXTRACELLULAR matrix ,POROSITY ,COLLAGEN ,RESIDUAL stresses ,ORTHOTROPY (Mechanics) - Abstract
Aims: To test for orthotropy in the stress-strain behavior of the temporomandibular joint (TMJ) disc under repeated physiologic loading before and after an impact event. Methods: Two groups, each consisting of 10 discs, were subjected to repeated tensile cycling in the dorsoventral (group 1) and mediolateral (group 3) direction. Two additional groups, each consisting of 10 discs, had preconditioning in the form of a 1.18 N·s impulsive load before tensile cycling in either the dorsoventral (group 2) or mediolateral (group 4) direction. Physiologic loads of 1 to 3 N were cycled at 0.1 Hz, and stress-strain responses were recorded every cycle between 1 to 10 cycles, and then periodically at 50, 100, 500, 750, and 1,000 cycles. The properties of elastic modulus, residual strain upon unloading, and area contained within the hysteresis loop were measured. Results: Dorsoventral loading produced 5-fold higher elastic modulus, 5-fold lower residual strain, and 5-fold lower hysteresis compared to mediolateral tensile loading (P ≤ .001). Repeated loading effectively reduced the viscous response for all discs, as the elastic modulus increased while residual strain and hysteresis decreased. Impulsive loading caused elastic modulus to increase for dorsoventrally cycled discs, whereas hysteresis decreased for mediolaterally cycled discs (P ≤ .05). Conclusion: The findings suggest that damage from the impact load may have increased the porosity of the extracellular matrix, which ultimately resulted in additional stress transfer to the collagen fibers during loading. Impulsive loads may be an important preconditioning factor in the fatigue failure of the TMJ disc in vivo. [ABSTRACT FROM AUTHOR]
- Published
- 2003
44. Search for HΛ6 hypernucleus by the Li6(π−,K+) reaction at pπ−=1.2 GeV/c
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A. O. Tokiyasu, Y. Shimizu, R. Kiuchi, N. Ishibashi, Michelangelo Agnello, Mifuyu Ukai, K. Shirotori, Megumi Naruki, C. W. Joo, K. Hosomi, T. Soyama, T. Shiozaki, Hiroyuki Tamura, Hiroyuki Noumi, Ryotaro Honda, Susumu Sato, Petr Evtoukhovitch, M. Sekimoto, B. J. Roy, Shuhei Hayakawa, P. K. Saha, K. Matsuoka, Ryosuke Ota, Atsushi Sakaguchi, R. Iwasaki, T. O. Yamamoto, H. C. Bhang, T. Takahashi, Y. Igarashi, Kenichi Imai, Chhanda Samanta, Koji Miwa, Seongbae Yang, A. Feliciello, S. Ajimura, Koichi Matsuda, K. Yoshida, Tomokazu Fukuda, Yutaka Mizoi, H. Fujioka, Hiroyuki Sako, J. K. Lee, Masaki Endo, Shoichi Hasegawa, Jae-Yong Lee, Kiyoshi Tanida, Nobuyuki Chiga, J. K. Ahn, Kanae Aoki, K. Tanabe, Y. Yamamoto, M. Moritsu, Hitoshi Sugimura, Takahiro Tanaka, Tomofumi Nagae, S. Nagamiya, Y. Sasaki, Manami Nakagawa, Y. Matsumoto, V. Samoilov, Toshiyuki Takahashi, Yudai Ichikawa, Z. Tsamalaidze, N. Amano, S. H. Hwang, and Yuya Akazawa
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Nuclear physics ,Baryon ,Physics ,Nuclear and High Energy Physics ,Particle decay ,Meson ,Isotopes of lithium ,Hadron ,Neutron ,Atomic physics ,Nucleon ,Hypernucleus - Abstract
We have carried out an experiment to search for a neutron-rich hypernucleus, 6 H, by the 6 Li(π − , K + ) reaction at pπ− =1.2 GeV/c. The obtained missing-mass spectrum with an estimated energy resolution of 3.2 MeV (FWHM) showed no peak structure corresponding to the 6 H hypernucleus neither below nor above the 4 H+2n particle decay threshold. An upper limit of the production cross section for the bound 6 H hypernucleus was estimated to be 1.2 nb/sr at 90% confidence level.
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- 2014
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45. Mechanobehaviour in dolichofacial and brachyfacial adolescents
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Laura R. Iwasaki, A. L. Weber, Jeffrey C. Nickel, Ying Liu, H. Liu, and P. Covington Riddle
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Male ,Adolescent ,Cephalometry ,Orthodontics ,Temporal Muscle ,Electromyography ,01 natural sciences ,Bite Force ,03 medical and health sciences ,0302 clinical medicine ,stomatognathic system ,Group differences ,0103 physical sciences ,medicine ,Humans ,Muscle activity ,010301 acoustics ,medicine.diagnostic_test ,Temporomandibular Joint ,business.industry ,Masseter Muscle ,030206 dentistry ,Numerical models ,Temporomandibular joint ,Biomechanical Phenomena ,stomatognathic diseases ,medicine.anatomical_structure ,Biting ,Otorhinolaryngology ,Face ,Surgery ,Ramus height ,Female ,Analysis of variance ,Oral Surgery ,business - Abstract
Structured AbstractObjectives To test whether mechanobehaviour (temporomandibular joint (TMJ) loads, jaw muscle use) was different between facial types and correlated with ramus height (Condylion-Gonion, mm). Setting and Sample Population University of Missouri-Kansas City (UMKC) Orthodontic Clinic. Ten dolichofacial and ten brachyfacial adolescents (Sella-Nasion–Gonion-Gnathion (SN-GoGn) angles ≥37° and ≤27°, respectively) consented to participate. Materials and Methods Numerical models calculated TMJ loads for a range of static biting based on subjects’ three-dimensional anatomy. Subjects were trained to record jaw muscle electromyography (EMG) over 2 days and 2 nights in their natural environments. Laboratory EMG/bite-force calibrations determined subject-specific EMG for 20 N bite-force (T20Nave). Jaw muscle use via duty factors (DF=muscle activity duration/total recording time, %) was determined from day and night recordings for muscle-specific thresholds from ≥5% to ≥80%T20Nave. ANOVA and Tukey's HSD post hoc tests assessed for group differences in mechanobehaviour (TMJ loads, DFs). Regression modelling correlated subjects’ normalized TMJ loads, DFs and ramus height. Results Dolichofacial compared to brachyfacial subjects produced significantly higher (P
- Published
- 2017
46. Search for Pentaquark Θ+in Hadronic Reaction at J-PARC
- Author
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S. Ishimoto, Shinichi Masumoto, Kenichi Imai, H. Fujioka, Y. Yonemoto, Tadayuki Takahashi, K. Hosomi, Y. Nozawa, G. G. Joo, Minu Kim, Hiroyuki Noumi, Shunsuke Adachi, Hirokazu Tamura, Yoichi Sato, Yudai Ichikawa, R. Kiuchi, Alessandro Feliciello, Hitoshi Takahashi, Seongbae Yang, Y. Igarashi, K. Matsuoka, N. Saito, Mifuyu Ukai, B. Bassalleck, Megumi Naruki, Michelangelo Agnello, Z. Tsamalaidze, Takeshi Koike, Atsushi Sakaguchi, Michiko Sekimoto, Kanae Aoki, M. Moritsu, T. O. Yamamoto, Masaharu Ieiri, Tomofumi Nagae, K. Shirotori, Elena Botta, K. Yagi, M. Niiyama, A. O. Tokiyasu, S. Y. Suzuki, V. V. Kulikov, S. Ajimura, C. J. Yoon, Shuhei Hayakawa, N. Ishibashi, K. Yoshida, Ryotaro Honda, Kiyoshi Tanida, H. Bang, R. Iwasaki, Koji Miwa, F. Hiruma, Susumu Sato, Petr Evtoukhovitch, V. Samoilov, Mitsuhiro Sato, Takahiro Tanaka, S. Sawada, Hiroyuki Sako, S. J. Kim, T. Takahashi, Ryosuke Ota, Y. Komatsu, Shunsuke Kanatsuki, Hiroyuki Ekawa, Hitoshi Sugimura, K. Itahashi, Y. Matsumoto, S. Marcello, N. Tomida, S. Bufalino, and Kyoichiro Ozawa
- Subjects
Nuclear physics ,Scattering cross-section ,Physics ,Particle physics ,Spectrometer ,Excited state ,Hadron ,High mass ,Superconducting magnet ,J-PARC ,Atomic and Molecular Physics, and Optics ,Pentaquark ,pentaquark - Abstract
The first experiment at the J-PARC hadron facility, the J-PARC E19 experiment, aims at searching for the Θ + pentaquark in the hadronic reaction π − p → K − X using the missing-mass technique. Based on a superconducting magnet excited at 2.5 T, the spectrometer achieved the high mass resolution of 1.4 MeV/c2 for the Θ + production process. The first data taking was performed in the autumn of 2010. No significant structure was observed in the missing-mass spectrum. The upper limit obtained for the differential cross section is 0.26 μb/sr in the laboratory frame at a 90 % CL.
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- 2013
47. Status of Superconducting Magnet System for the J-PARC Neutrino Beam Line
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Hirokatsu Ohhata, M. Shibata, A. Jain, Ken-ichi Sasaki, Nobuhiro Kimura, K. Nakayoshi, Takahiro Okamura, A.K. Ghosh, O. Araoka, T. Ishii, M. Iida, Joseph Muratore, R. Iwasaki, H. Kakuno, Toru Ogitsu, Takashi Kobayashi, T. Nakadaira, J. Escallier, Yasuhiro Makida, Tatsushi Nakamoto, G. Ganetis, Y. Fujii, Ramesh Gupta, K. Sakashita, Minoru Yoshida, Michael Anerella, Ryutaro Okada, J. P. Charrier, T. Boussuge, P. Wanderer, Michinaka Sugano, and Brett Parker
- Subjects
Cryostat ,Physics ,Nuclear engineering ,Superconducting magnet ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Nuclear physics ,Electromagnetic coil ,Magnet ,Damages ,Recovery procedure ,J-PARC ,Electrical and Electronic Engineering ,Neutrino - Abstract
The Great East Japan earthquake that occurred on March 11, 2011 resulted in devastating damages to J-PARC. Although damages to the superconducting magnet system for the J-PARC neutrino beam line appeared to be relatively small, a long recovery procedure was required to resume the operation. Except for this long shutdown period, the system has been operated stably ensuring good accumulation of the physics data. The paper reports on the operation status including the damages by the earthquake and its recovery process. Repair of the insufficient cooling of steering corrector coils, which was present prior to the earthquake, was also performed during the recovery process. The paper also reports on the repair.
- Published
- 2011
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48. Comparison between cone-beam computed tomography and intraoral digital radiography for assessment of tooth root lesions
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Laura R. Iwasaki, Karen B. Williams, Jeffrey C. Nickel, Lauren Gossett, Vandana Kumar, and Ashley Blattner
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Cone beam computed tomography ,Swine ,Radiography ,Root Resorption ,Dentistry ,Orthodontics ,Root resorption ,Tooth root ,stomatognathic system ,Incisor ,Image Processing, Computer-Assisted ,medicine ,Animals ,Humans ,X-Ray Intensifying Screens ,Maxillary central incisor ,Tooth Root ,Radiography, Bitewing ,Digital radiography ,Observer Variation ,business.industry ,Mandible ,Radiography, Dental, Digital ,Cone-Beam Computed Tomography ,medicine.disease ,medicine.anatomical_structure ,business - Abstract
Introduction Cone-beam computed tomography (CBCT) might be more accurate in identifying radicular surface lesions compared with digital periapical radiography. In this study, we compared these techniques in detecting simulated root resorption lesions. Methods A porcine mandible was used to support 10 human maxillary central incisors. CBCT and digital periapical radiographic images were generated before and after the introduction of standardized and sequentially larger root defects on either the mesial or the lingual root surfaces. The images were randomly labeled and evaluated by 3 examiners. Each image was classified according to defect size (0, none; 1, mild; 2, moderate; 3, severe). Results Interrater reliability was acceptable (0.856 ≤P ≤0.981). The location of the root defect (mesial vs lingual) had no significant effect on the evaluation of defect size. Both periapical radiographs and CBCT were slightly better at detecting lingual defects than mesial defects (75% vs 65% and 65% vs 60%, respectively), but these effects were not statistically significant (P = 0.49 and P = 0.74, respectively). The mean percentages of correctly diagnosed defect sizes were 65% for CBCT and 75% for periapical radiographs. Examiners using CBCT images tended to overestimate defect sizes (κ = 0.481) and correctly categorized teeth with no, mild-moderate, and severe defects 80%, 45%, and 90% of the time, respectively. Examiners using periapical radiographs tended to underestimate defect sizes (κ = 0.636) and categorized teeth with no, mild-moderate, and severe defects 100%, 50%, and 100% of the time, respectively. Conclusions There was no difference in accuracy of identifying defects between periapical radiographs and CBCT images.
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- 2011
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49. Reliability of electromyographic activity vs. bite-force from human masticatory muscles
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J. C. Nickel, E. Lozier, Yoly Gonzalez, Richard Ohrbach, W.D. McCall, and L. R. Iwasaki
- Subjects
medicine.diagnostic_test ,business.industry ,Intraclass correlation ,Electromyography ,Anatomy ,Masticatory force ,Bite force quotient ,medicine.anatomical_structure ,Biting ,Incisor ,Suprahyoid muscles ,Medicine ,medicine.symptom ,business ,General Dentistry ,Muscle contraction - Abstract
The reproducibility of electromyographic (EMG) activity in relation to static bite-force from masticatory muscles for a given biting situation is largely unknown. Our aim was to evaluate the reliability of EMG activity in relation to static bite-force in humans. Eighty-four subjects produced five unilateral static bites of different forces at different biting positions on molars and incisors, at two separate sessions, and the surface EMG activities were recorded from temporalis, masseter, and suprahyoid muscles bilaterally. Intraclass correlation coefficients (ICCs) were determined, and an ICC of ≥ 0.60 indicated good reliability of these slopes. The ICCs for jaw-closing muscles during molar biting were: temporalis muscles, ipsilateral 0.58-0.93 and contralateral 0.88-0.91; and masseter muscles, ipsilateral 0.75-0.86 and contralateral 0.69-0.88. The ICCs for jaw-closing muscles during incisor biting were: temporalis muscles, ipsilateral 0.56-0.81 and contralateral 0.34-0.86; and masseter muscles, ipsilateral 0.65-0.78 and contralateral 0.59-0.80. For the suprahyoid muscles the 95% CIs were mostly wide and most included zero. The slopes of the EMG activity vs. bite-force for a given biting situation were reliable for temporalis and masseter muscles. These results support the use of these outcome measurements for the estimation and validation of mechanical models of the masticatory system.
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- 2011
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50. Human Temporomandibular Joint Eminence Shape and Load Minimization
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W.D. McCall, Richard Ohrbach, Yoly Gonzalez, Michael J. Crosby, Jeffrey C. Nickel, Laura R. Iwasaki, and David B. Marx
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Adult ,Male ,Joint Dislocations ,medicine.disease_cause ,Models, Biological ,Weight-bearing ,Dental Occlusion ,Weight-Bearing ,Young Adult ,Temporomandibular Joint Disc ,medicine ,Humans ,Range of Motion, Articular ,General Dentistry ,Joint (geology) ,Mathematics ,Temporomandibular Joint ,Dental occlusion ,Mandibular Condyle ,Biomechanics ,Research Reports ,Vertical Dimension ,Anatomy ,Middle Aged ,Temporomandibular Joint Disorders ,Biomechanical Phenomena ,Temporomandibular joint ,Cross-Sectional Studies ,medicine.anatomical_structure ,Facial Asymmetry ,Masticatory Muscles ,Female ,Crest ,Stress, Mechanical ,Facial symmetry - Abstract
Analysis of previous data suggested the hypothesis that temporomandibular joint (TMJ) eminence shapes develop ideally to minimize joint loads. Hence, we tested this hypothesis in nine females and eight males in each of two groups, with and without TMJ disc displacement. Participants provided anatomical data used in a joint load minimization numerical model to predict, and jaw-tracking data used to measure, eminence shapes. Coordinate data (x,y) of shapes were fit to third-order polynomials for two sessions, sides, and methods (predicted, measured) for each participant. Inter-session data were reliable and averaged. Those with, compared with those without, disc displacement had higher measured shape range (5:1) and left-right asymmetry prevalence (4:1). In 29 symmetrical individuals, ANCOVA and Bonferroni tests compared vertical dimensions (y) at 11 postero-anterior points (x), 0.5 mm apart. Model-predicted and measured shapes were significantly different (P ≤ 0.01) near the eminence crest, but joint load minimization was consistent with eminence shape for x < 3.0 mm.
- Published
- 2010
- Full Text
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