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Aim: This in vitro study was aimed to evaluate the effect of adding different concentrations of chitosan nanoparticles (NPs) and TiO2 NPs on the shear bond strength (SBS) of an orthodontic adhesive. Materials and Methods: In this in vitro study, 72 extracted human premolars were embedded in an acrylic resin and randomly allocated into four groups of 18 specimens. In group 1 (control), brackets were bonded to the tooth with the Transbond XT orthodontic adhesive. In groups 2, 3, and 4, 0.5% chitosan NPs and 0.5% TiO2 NPs, 1% chitosan NPs and 1% TiO2 NPs, and 1.5% chitosan NPs and 1.5% TiO2 NPs were added to Transbond XT, respectively. Then, the brackets were bonded by the modified adhesive. The SBS and adhesive remnant index (ARI) of each group were assessed with a universal testing machine. The SBS test results were analyzed using one-way analysis of variance followed by the posthoc Tukey’s honestly significant difference (HSD) test. The Kruskal–Wallis test was also applied to evaluate the ARI scores. Results: The results showed no statistically significant difference between groups 1, 2, and 3, but SBS decreased significantly in group 4. With increasing the concentration of NPs up to 1% chitosan NPs and 1% TiO2 NPs, SBS did not change significantly. However, in 1.5% chitosan NPs and 1.5% TiO2 NPs, SBS decreased compared to the other three groups. No significant differences were found between the groups in terms of ARI scores. Conclusion: It is concluded that the orthodontic composite containing 1% chitosan NPs and 1% TiO2 NPs has adequate SBS for use in the clinical setting.

Background: Following the declaration of the COVID-19 national emergency, screening mammograms (SM) abruptly dropped across the United States. Stay-at-home orders discourage cancer patients from seeking care, and cancer screenings and surgeries were postponed. Upon resumption of screening services, rates of screening were slow to recover. At Baylor St. Luke’s CHI (BSL), one of the largest tertiary care centers providing comprehensive cancer screening in Houston, we investigated patient level predictors, including comorbidities and area deprivation index (ADI), and the risk of skipping SM in the first year of the COVID-19 Pandemic. Methods: We used the local PENRAD database to retrieve the monthly gross number of SM performed at all BSL sites from 02/2018 to 01/2021. We obtained patient level data through EPIC, including address and demographics, comorbid conditions e.g., diabetes, hypertension, obesity (BMI30), chronic kidney disease and cardiovascular diseases (CVD). We identified ADI associated with patient addresses. We included patient who received at least one SM between 02/2018 to 01/2020. We compared patients did not get a mammogram in the first year of the pandemic; 02/2020 to 01/2021, to those who maintained screening during the pandemic. We performed a logistic regression analysis to assess the influence of age, 0 to +3 comorbid conditions, and ADI in quartiles on the odds ratio of skipping SM in the first year of the pandemic. Statistical significance was set at p< 0.05. The study was IRB approved. Results: Out of the 4591 women that screened in 2018 and/or 2019, only 1628 came back for SM in 2020 (35.5%). Women who obtained SM during the pandemic vs those who did not were slightly older, mean age 58 vs 56 (P< 0.001), were less likely to be living in the most deprived neighborhood, Q4 of ADI, 23.8% vs. 25.6%, more likely to be obese 39% vs. 35% (P< 0.001), more likely to have diabetes 48% vs. 41% (P< 0.001), more likely to have CVD, 16% vs. 13% (P< 0.001), and more likely to have hypertension 80% vs. 71% (P< 0.001). On multivariate logistic regression, living in Q4 ADI was associated with 22% higher risk of skipping SM in 2020 (95% CI 1.02-1.42), having one vs. two vs. three comorbid conditions increased the likelihood of obtaining SM in 2020 by 25% (95% CI 0.62-0.91) vs. 30% vs (95% CI 0.58-0.85), 42% (95% CI 0.48-0.7) compared to no comorbid conditions. Conclusion: Women living in Q4 of the ADI (most deprived neighborhood) were more likely to miss 2020 screening when compared with the Q1 women (least deprived neighborhood). The more chronic diseases women had, the less likely they were to skip 2020 screening when compared with those that had no chronic disease. This could because women with many health issues have to frequent health facilities at higher rates and thus less likely to miss mammograms. Citation Format: Maryam Nemati Shafaee, Omar Rosales, Randall Parker Kirby, Tamara Ortiz-Perez, Luke Gilman, Ashley Hardeman, Preeya Bhavsar Bhakta, Chris Amos, Abiodun Oluyomi. Patient-level predictors of skipping screening mammograms during the COVID-19 pandemic at a large tertiary care center in Texas [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-03-25.

In this study, numerical simulation is employed to diagnose the behavior of round liquid jet under forced perturbation with the low-velocity coaxial gas flow. A sinusoidal longitudinal perturbation with high amplitude and infinite frequency is imposed on the inlet of the liquid jet. An annular gas with lower velocity flows coaxially. The volume of fluid (VOF) approach is used to capture the liquid-gas interface. Various circumstances are considered such as properties of the liquid, the ratio of gas velocity to liquid velocity, and the properties of perturbation. Different cap formations, ligament breakup, and the droplet generation processes are depicted. The results indicate that the slower gas flow can affect the liquid jet breakup behavior and droplet generation. Also, liquid properties can considerably influence the cap formation and morphology of breakup. This investigation is validated by other numerical and experimental research in the basic conditions, while co-flowing gas-liquid jet considered in the present study is completely novel.

In this study, a numerical simulation is used to show the physics of a coupled forced perturbation and liquid jet in the presence of a low-velocity coaxial gas flow. The volume of fluid (VOF) approach is employed to capture the liquid–gas interface. A sinusoidal velocity with a finite frequency and amplitude is applied at the liquid jet inlet to define a forced perturbation. An annular gas flow with a velocity lower than that of the liquid jet is imposed to examine its influence on the liquid jet breakup mechanism. The annular gas flow is modulated by the sinusoidal velocity inlet, and the effect of this flow on the liquid jet breakup mechanism is analyzed. Different ratios of the gas velocity to liquid velocity are studied. The results indicate that the low-velocity gas flow can considerably affect the behavior of the liquid jet, and this effect becomes more significant as the amplitude of the forced perturbation increases.

Giant pedunculated hepatocellular adenomas are extremely rare tumors and often detected incidentally on cross-sectional imaging studies. We report the case of a 34-year-old woman who underwent cross-sectional imaging for staging evaluation of a uterine tumor. A large left subdiaphragmatic mass, without clear connection to the liver, was seen prompting diagnostic laparoscopy; during which a large pedunculated mass attached to the left lobe of the liver was found and resected. This case report highlights the challenges and pitfalls in the imaging diagnosis of pedunculated hepatocellular adenomas, such as difficulty in characterizing the mass or inability to identify the vascular attachment to the liver. Image-guided biopsy and diagnostic laparoscopy are valuable tools to establish diagnosis; most of these lesions are amenable to laparoscopic resection.

The enhancement of heat transfer rate in heat exchangers has been considered a major concern. In this research, the impacts of inserting twisted tapes in horizontal two-phase flow heat exchangers are discussed, and different values of vapor qualities (in the range of 0.1 to 0.7) and mass velocities (in the range of 119 to 367 kgm−2s−1) are considered during forced convective condensation of R600a (Isobutane). The test case is a pipe made from copper with an inner diameter of 8.1 mm and a length of 1000 mm. Furthermore, three twisted tape inserts with various twist ratios (defined as the ratio of the twisted tape pitch to the test pipe inner diameter) of 4, 10, and 15 are used. The results illustrated that installing twisted tapes results in the increment of pressure drops and the rate of heat transfer in comparison to the smooth case. Furthermore, the pressure drops and heat transfer rates augment as the refrigerant mass velocity and vapor quality increase. Depending on the inserts type and operating conditions, the performance factor (a criterion to assess the performance modification compared to the primary test case) between 0.39 to 1.05 was obtained. It was also observed that there exists an optimum amount of the refrigerant mass velocity at which the performance factor is higher. Results showed that generally using twisted tapes in heat exchangers is not instrumental unless when the main concern is to improve the heat transfer rate or when the augmented power consumed by pump can be justified.

Despite the hazards of asteroids, utilization of their resources and useful materials have been raised recently. In some scenarios, capturing and controlling asteroids are essential for asteroid mining. To this end, a reliable detumbling mission using a swarm of CubeSats, each equipped with a low-thrust thruster, is proposed in this paper. The landing location and the orientation of each CubeSat on an ellipsoidal asteroid are determined by designing optimal CubeSat (thruster) configuration according to a minimum number of required CubeSats for maximizing reliability and minimizing fuel consumption with a specific level of redundancy using a Genetic Algorithm. The feasibility of the configuration is examined using the geometric method. Examining the proposed configuration through a simulation shows acceptable performance with the desired reliability and level of redundancy.

Objective The main aim of this study was to evaluate the effect of immediate versus delayed addition of the nasal stent to the nasoalveolar molding plate on the nose shape and alveolar cleft area in unilateral cleft lip and palate infants. Method Twenty nonsyndromic newborn infants with unilateral cleft lip and palate were scanned 3 dimensionally using Proface software. In the experimental group, the nasal stent was added on the day the molding plate arrived, and in the control group when the alveolar gap reached 5 mm. Two months after adding nasal stents in each group patients' faces were scanned again and some parameters were measured. In addition, immediately after treatment, 1 month later and at the end of investigation, impressions were taken, and stone casts were scanned by cone-beam computed tomography and the alveolar gap was measured. Fisher exact test, paired t test, and ANOVA were used for data analyses. P Results In this study, changes in the parameters showed significant differences between the case and controls for the columellar angle, nostril width on the cleft side, nostril height on the cleft side, soft tissue cleft width, and nasal surface area. However, the nostril's width and height in the noncleft side, intercommissural distance, nasal surface area on the noncleft side, nostril area between the cleft and noncleft side after treatment, and the alveolar gap did not show significant differences between the groups (P > 0.05). Conclusion Early use of nasal stents showed more desirable results in decreasing the width of the nostrils and increasing its height and correcting the angle of the columella without any adverse effects on the nostrils after treatment.

Background Carpal tunnel release (CTR) is acknowledged as a predisposing factor for the development of the trigger finger. However, the incidence of new-onset trigger finger after CTR surgery has been inconsistently reported. In this study, we aimed to evaluate the prevalence of CTR as a risk factor of the development of the trigger finger. Methods In a retrospective study, 57 consecutive patients who underwent surgery for the treatment of trigger finger were included. The severity of carpal tunnel syndrome (CTS) was determined using the electromyogram test and nerve conduction study. The clinical and demographic characteristics of the patients were extracted from their medical profiles and compared between patients who did and did not develop a trigger finger after CTR. Results Post-CTR trigger finger was detected in 15 (26.3%) patients. The trigger finger occurred approximately six months after CTR surgery. The thumb and ring fingers were the most commonly involved fingers. Ten out of 15 (66.7%) patients who developed a post-CTR trigger finger had mild-to-moderate CTS, and five (33.3%) patients had severe CTS. No significant difference was found between the patients who did and did not develop a trigger finger after CTR. Conclusion The rate of developing a post-CTR trigger finger was remarkable in our study. Therefore, the potential sequelae should be discussed with patients, preoperatively.

Elastomer diaphragm tanks have been adopted in many spacecraft applications, such as upper stages, space platforms, commercial and civil spacecraft as a propellant tank in which liquid propellant is covered with a diaphragm and compressed into a combustion chamber by gas pressure. Investigating the dynamic response and the influence of various parameters on the modal properties is a significant issue in the modeling of the space diaphragm tanks. In this work, the numerical study is presented to investigate the modal properties of a spherical fuel tank in both uncovered and covered cases with a flexible diaphragm as fluid–structure interacting situations. The filling volume ratio of fluid ranges is from 25 to 50%. Numeric dynamic simulations created by ANSYS software are verified by the experimental results of test tank and then, the validation of the numeric model is used to determine the natural frequencies and mode shapes of really elastomer diaphragm tank as the second case study for two conditions: fluid filling volume ratio of 80% that the tank is in full load condition and liquid filling volume ratio of 14% when the diaphragm completely inverted. After that, the best layout of diaphragm tanks in two-story satellite is detected by calculating deviations from center of gravity and cross moments of inertia objective functions in multi objective optimization software. Then the natural frequencies of satellite include diaphragm tanks computed and compared with natural frequencies and static loads of launch vehicle requirements. The achieved results of this study showed that the numeric simulations are able to renovate the experimental vibration characteristics of the diaphragm tank with a good precision. In addition numeric model can detect the best layout of diaphragm tank components.

Aims & Backgrounds: The US and the Soviet Union led the east and the west camps during the cold war and the geopolitical order was laid on the foundation of the rivalries between these two superpowers. But, after the collapse of the bipolar system, the US became the undisputed power in the international arena and the geopolitical order underwent changes during three decades after that and the conflicts between the superpowers was continued. Based thereon, the current study aims at explaining the geopolitical structure after the cold war and the method of power distribution in the situation after the collapse of Soviet Union up to the present time. Methodology: The present study makes use of a descriptive-analytical method using qualitative content analysis and reviewing literature and the theories presented through reasoning and inference to find answers to three key questions in line with perceiving the relations between the superpowers after the cold war. The method of data and information Collectionis library and documentary. Findings: The present study will show that the world witnessed a geopolitical transition after cold war and that no power is in a hegemonic position currently and the world is bearing witness to a spectrum of unipolar, bipolar and multipolar fluid powers. The conflict between the superpowers can be explained based on subjective and objective geopolitical factors. Conclusion: Powers have chosen such strategies as withdrawal, bandwagoning and, balance of power which is including soft and hard in respect to one another according to the type of conflicts

Cisplatin is commonly used as a chemotherapeutic agent useful in the treatment of several forms of cancer, but its use is limited due to the undesirable side effects of nephrotoxicity. Most of the previous researches found a positive effect of using selenium as an antioxidant on the toxicity of cisplatin during short term administrations although the recommended dose regimen of cisplatin in chemotherapy is multiple successive administration every three or four weeks depending on the type of the tumor. The aim of this study was to examine the effects of long term usage of selenium or nano-selenium on cisplatin-induced nephrotoxicity in albino rats. Forty rats were divided into equal four groups, 1st group as a control injected with normal saline, 2nd group injected with cisplatin 6 mg/kg every 21 days for 70 days (experimental period), 3rd group injected with cisplatin 6 mg/kg plus intramuscular injection 0.1 mg/kg selenium in the form of sodium selenite every 3 days during the experimental period, the 4th group injected with cisplatin 6 mg/kg plus intramuscular injection 0.1 mg/kg nano-selenium every 3 days during the experimental period. The results indicated that selenium or nano-selenium exerted an antioxidant effect through increasing the level of antioxidant enzymes in both serum and kidney tissue, while, it shows a negative effect on kidney function through increasing serum urea and creatinine concentrations and causing abnormal morphology of kidney tissue for rats treated with cisplatin during experimental period.

Background: Deleterious BRCA mutations confer a significant lifetime risk of breast cancer (BC) as well as contralateral BC (CBC) in patients who do not undergo prophylactic mastectomy. Prior reports have suggested that tamoxifen reduces the risk of CBC in BRCA mutation carriers. Whether aromatase inhibitors (AI) have the same effect is unknown. Methods: This is a retrospective review of patients diagnosed with non-metastatic ER+ BC between 2004-2014 with known BRCA mutation status. Patients were followed from primary diagnosis until CBC diagnosis or death. Median follow up was 11.5 years. Risk of CBC was evaluated as time to event. Results: 935 subjects were included in this analysis, with 53 BRCA1 mutation carriers, and 94 BRCA2 mutation carriers. Median age at diagnosis was 42.7 years. Seventy-two percent (676) received tamoxifen and 43% (405) received AI. A total of 66 CBCs occurred, of which 10% (15/147) occurred in BRCA mutation carriers vs %6.5 (51/788) in BRCA wild type. Multivariate analyses indicated that BRCA status and AI use were significantly associated with CBC risk. AI use resulted in a significant reduction in risk of CBC (HR 0.44, p=0.004) regardless of the BRCA mutation status. Tamoxifen use was not associated with reduced risk of CBC. Conclusions: This is the first report showing that AIs reduce the risk of CBC in BRCA mutation carriers. The potential role of AIs as chemoprevention should be validated in larger independent cohorts.

Deleterious BRCA mutations confer a significant lifetime risk of breast cancer (BC) as well as contralateral BC (CBC) in patients who do not undergo prophylactic mastectomy. Prior reports have suggested that tamoxifen reduces the risk of CBC in BRCA mutation carriers. Whether aromatase inhibitors (AI) have the same effect is unknown.This is a retrospective review of patients diagnosed with non-metastatic ER+ BC between 2004 and 2014 with known BRCA mutation status. Patients were followed from primary diagnosis until CBC diagnosis or death. Median follow-up was 11.5 years. Risk of CBC was evaluated as time to event.935 subjects were included in this analysis, with 53 BRCA1 mutation carriers, and 94 BRCA2 mutation carriers. Median age at diagnosis was 42.7 years. Seventy-two percent (676) received tamoxifen and 43% (405) received AI. A total of 66 CBCs occurred, of which 10% (15/147) occurred in BRCA mutation carriers vs 6.5% (51/788) in BRCA wild type. Multivariate analyses indicated that BRCA status and AI use were significantly associated with CBC risk. AI use resulted in a significant reduction in risk of CBC (HR 0.44, p = 0.004) regardless of the BRCA mutation status. Tamoxifen use was not associated with reduced risk of CBC.This is the first report showing that AIs reduce the risk of CBC in BRCA mutation carriers. The potential role of AIs as chemoprevention should be validated in larger independent cohorts.

Objectives: The use of mobile technologies and handheld computers by physicians has increased worldwide. However, there are limited studies globally regarding training physicians on the use of such devices in clinical practice. In addition, no studies have been conducted previously in Oman addressing this issue among postgraduate medical trainees and trainers. The present study explores the practice and perception of resident doctors and trainers towards the use of mobile technologies and handheld devices in healthcare settings in Oman. Methods: This cross-sectional study was conducted using a validated questionnaire disseminated via email to all residents and trainers in five major training programs of the Oman Medical Specialty Board (OMSB). The questionnaire explored three main areas; perception, usage, and perceived barriers of handheld devices. Results: Overall, 61.4% of the residents and 28.3% of the trainers responded to the questionnaire. Both types of participants agreed that the use of such devices positively affects clinical decision-making. In total, 98.8% of the participating residents and 86.7% of the trainers frequently used handheld devices. Both OMSB residents and trainers agreed that lack of time, training, and applications were the most common factors limiting the use of these devices. Participants emphasized the need for constructive training regarding the use of handheld devices as healthcare resources. Conclusions: Point-of-care devices are positively perceived and frequently used by OMSB trainees and trainers. However, constructive training on the effective usage of these devices in clinical decision-making is needed. Further future studies to evaluate the impact of using such devices in patient care should be conducted.