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Since its introduction into agricultural education programs in the 1970s, agricultural leadership has continued to change due to the needs of students and trends within the field (Cletzer et al., 2020; Jones, 2004; Williams, 2007). A single research question guided the study: What is the nature of graduate agricultural leadership courses offered in the United States? This study utilized a qualitative content analysis to capture the meanings, emphasis, and themes of agricultural leadership graduate course descriptions. The frame for this research was established by consulting the American Association of Agricultural Educators member list. University course catalogs were reviewed, and all graduate coursework offered by the agricultural education departments of the identified institutions that included any of the following terms in the title were noted: (a) lead, (b) leader, and (c) leadership. A total of 62 courses from 11 institutions met the criteria. The findings clustered the courses into 21 categories, further compiled into six themes: (1) individual-level focus, (2) organizational-level focus, (3) societal-level focus, (4) professional focus, (5) methodological focus, (6) developmental focus. The findings and recommendations should be considered by agricultural leadership educators as they evaluate how to most appropriately grow their academic programs and coursework.

Introduction The current study applied an intersectional lens to examine societal factors, individual psychological outcomes, and youth combustible tobacco and vape use at the intersection of sexual and/or gender minority (SGM) status and race and/or ethnicity. Aims and Methods Data were drawn from 133 969 youth respondents surveyed in the 2019–2020 California Student Tobacco Survey, a representative school-based survey of 8th and 10th-grade public school students throughout California. The impact of multiple marginalized group membership using four mutually exclusive intersectional positions (non-SGM white, SGM white, racial minority only, and both SGM and racial minority), in addition to specific differences across ten SGM by race and/or ethnicity groups (e.g. non-SGM black or African American, SGM black or African American, etc.) were assessed. Results Compared to heterosexual and cisgender white youth, SGM and racial minority adolescents were shown to experience poorer school tobacco education quality and cessation support, lower school and family connectedness, and higher anxiety and depression symptoms. SGM and racial minority youth had a higher prevalence of ever-combustible tobacco use but were less likely to be current vape users compared to non-SGM white respondents. In examining specific group differences, results revealed that SGM teens had the highest risk of ever combustible tobacco use. This disparity was amplified for those belonging to multiple marginalized groups, with black or AA SGM teens evidenced to be at the highest risk of current combustible tobacco. Conclusions Information from this study has useful implications for SGM measurement in surveillance systems and highlights the usefulness of adopting an intersectional approach to inform equity-driven public health policy and intervention. Implications This representative study of California youth supports that identifying as a sexual and/or gender minority (SGM) is an important risk factor for combustible tobacco use. Particularly, observed SGM disparities were magnified for the youth belonging to marginalized groups, as black or African American SGM teens were shown to be at the highest risk of current combustible tobacco use. Findings support that Intersectionality Theory represents a useful framework for examining tobacco-related disparities and underscores the importance of assessing how the intersection of multiple social categories impacts youth tobacco use.

Introduction Flavored tobacco appeals to new users. This paper describes evaluation results of California’s early ordinances restricting flavored tobacco sales. Methods A multicomponent evaluation of proximal policy outcomes involved the following: (a) tracking the reach of local ordinances; (b) a retail observation survey; and (c) a statewide opinion poll of tobacco retailers. Change in the population covered by local ordinances was computed. Retail observations compared availability of flavored tobacco at retailers in jurisdictions with and without an ordinance. Mixed models compared ordinance and matched no-ordinance jurisdictions and adjusted for store type. An opinion poll assessed retailers’ awareness and ease of compliance with local ordinances, comparing respondents in ordinance jurisdictions with the rest of California. Results The proportion of Californians living in a jurisdiction with an ordinance increased from 0.6% in April 2015 to 5.82% by January 1, 2019. Flavored tobacco availability was significantly lower in ordinance jurisdictions than in matched jurisdictions: menthol cigarettes (40.6% vs. 95.0%), cigarillos/cigar wraps with explicit flavor descriptors (56.4% vs. 85.0%), and vaping products with explicit flavor descriptors (6.1% vs. 56.9%). Over half of retailers felt compliance was easy; however, retailers in ordinance jurisdictions expressed lower support for flavor sales restrictions. Conclusions The proportion of California’s population covered by a flavor ordinance increased nine-fold between April 2015 and January 2019. Fewer retailers in ordinance jurisdictions had flavored tobacco products available compared to matched jurisdictions without an ordinance, but many still advertised flavored products they could not sell. Comprehensive ordinances and retailer outreach may facilitate sales-restriction support and compliance.

ObjectiveTo describe an approach for reporting master protocol research programs (MPRPs) that is consistent with existing good reporting practices and that uses structured information to convey the overall master protocol and design of each substudy.DesignQualitative analysis.Data sourcesClinicalTrials.gov trial registry.Main outcome measuresEstablished goals and related practices of the trial reporting system were outlined, examples and key characteristics of MPRPs were reviewed, and specific challenges in registering and reporting summary results to databases designed for traditional clinical trial designs that rely on a model of one study per protocol were identified.ResultsA reporting approach is proposed that accommodates the complex study design of MPRPs and their results. This approach involves the use of separate registration records for each substudy within one MPRP protocol (with potential exceptions noted).ConclusionsHow the proposed approach allows for clear, descriptive, structured information about each substudy’s prespecified design and supports timely reporting of results after completion of each substudy is described and illustrated. Although the focus is on reporting to ClinicalTrials.gov, the approach supports broader application across trial registries and results databases. This paper is intended to stimulate further discussion of this approach among stakeholders, build awareness about the need to improve reporting of MPRPs, and encourage harmonization across trial registries globally.

Cerebral cortex thinning and cerebral blood flow (CBF) reduction are typically observed during normal healthy aging. However, imaging-based age prediction models have primarily used morphological features of the brain. Complementary physiological CBF information might result in an improvement in age estimation. In this study, T1-weighted structural magnetic resonance imaging and arterial spin labeling CBF images were acquired in 146 healthy participants across the adult life span. Sixty-eight cerebral cortex regions were segmented, and the cortical thickness and mean CBF were computed for each region. Linear regression with age was computed for each region and data type, and laterality and correlation matrices were computed. Sixteen predictive models were trained with the cortical thickness and CBF data alone as well as a combination of both data types. The age explained more variance in the cortical thickness data (average R2 of 0.21) than in the CBF data (average R2 of 0.09). All 16 models performed significantly better when combining both measurement types and using feature selection, and thus, we conclude that the inclusion of CBF data marginally improves age estimation.

Interviews and focus groups are seminal core methodologies in the social sciences. However, how does a researcher elicit meaningful information when interviews and focus groups result in silence? T...

The current study examined race- and ethnicity-based differences in the reasons that youth report for vaping, with an emphasis on understanding the relationship between race/ethnicity and vaping for relaxation and stress/anxiety coping. This work also sought to go beyond examining race-based differences as a cause of tobacco-use disparities by assessing social connectedness factors that mediate relationships between race/ethnicity and vaping for relaxation and coping. Research questions were tested using data from the 2019-2020 California Student Tobacco Survey, a representative school-based survey of 10th and 12th grade public school students throughout schools in California. Overall, 7.78% of the sample reported using nicotine vapes in the past 30 days. The final sample included 11,112 high school student current vape users. The most important reason that youth vaped was for relaxation and stress/anxiety coping, with racial and ethnic minorities most likely to report this vaping motivation. Analyses of the structural mechanisms underlying the relationship between race/ethnicity and vaping reasons showed that minority youth reported lower school, peer, and family connectedness when compared to White youth. Lower school and family connectedness were in turn correlated with being motivated to vape to relax or relieve stress and anxiety, and lower overall mental health. Findings imply that future intervention efforts might profitably focus on reducing stressors associated with relaxation and stress/anxiety coping motivations and highlight the importance of connectedness for indirectly decreasing vape use risk by improving negative mood and mental health.

Introduction Pre‐treatment blood oxygenation level‐dependent (BOLD) functional magnetic resonance imaging (fMRI) has been used for the early identification of patients with major depressive disorder (MDD) who later respond or fail to respond to medication. However, BOLD responses early after treatment initiation may offer insight into early neural changes associated with later clinical response. The present study evaluated both pre‐treatment and early post‐treatment fMRI responses to an emotion processing task, to further our understanding of neural changes associated with a successful response to pharmacological intervention. Methods MDD patients who responded (n = 22) and failed to respond (n = 12) after 8 weeks of treatment with either citalopram or quetiapine extended release, and healthy controls (n = 18) underwent two fMRI scans, baseline (pre‐treatment), and early post‐treatment (one week after treatment commencement). Participants completed an emotional face matching task at both scans. Results Using threshold‐free cluster enhancement (TFCE) and non‐parametric permutation testing, fMRI activation maps showed that after one week of treatment, responders demonstrated increased activation in the left parietal lobule, precentral gyrus, and bilateral insula (all P, Patients diagnosed MDD who later went on to respond to medication showed robust BOLD increases after one week of treatment to an emotion processing task. There were no differences between responders, non‐responders and healthy controls at baseline, indicating that BOLD fMRI can be used to identify mediating markers of treatment response.

10-Year Update on ClinicalTrials.gov A decade after ClinicalTrials.gov launched a database for reporting results of clinical trials, the database includes results of approximately 36,000 trials. Th...

Youth violence is a growing challenge worldwide, particularly in countries that are experiencing extreme social disorganisation. This is exemplified in Honduras which has been one of the top five c...

Importance Extenuating circumstances can trigger unplanned changes to randomized trials and introduce methodological, ethical, feasibility, and analytical challenges that can potentially compromise the validity of findings. Numerous randomized trials have required changes in response to the COVID-19 pandemic, but guidance for reporting such modifications is incomplete. Objective As a joint extension for the CONSORT and SPIRIT reporting guidelines, CONSERVE (CONSORT and SPIRIT Extension for RCTs Revised in Extenuating Circumstances) aims to improve reporting of trial protocols and completed trials that undergo important modifications in response to extenuating circumstances. Evidence A panel of 37 international trial investigators, patient representatives, methodologists and statisticians, ethicists, funders, regulators, and journal editors convened to develop the guideline. The panel developed CONSERVE following an accelerated, iterative process between June 2020 and February 2021 involving (1) a rapid literature review of multiple databases (OVID Medline, OVID EMBASE, and EBSCO CINAHL) and gray literature sources from 2003 to March 2021; (2) consensus-based panelist meetings using a modified Delphi process and surveys; and (3) a global survey of trial stakeholders. Findings The rapid review yielded 41 673 citations, of which 38 titles were relevant, including emerging guidance from regulatory and funding agencies for managing the effects of the COVID-19 pandemic on trials. However, no generalizable guidance for all circumstances in which trials and trial protocols might face unanticipated modifications were identified. The CONSERVE panel used these findings to develop a consensus reporting guidelines following 4 rounds of meetings and surveys. Responses were received from 198 professionals from 34 countries, of whom 90% (n = 178) indicated that they understood the concept definitions and 85.4% (n = 169) indicated that they understood and could use the implementation tool. Feedback from survey respondents was used to finalize the guideline and confirm that the guideline’s core concepts were applicable and had utility for the trial community. CONSERVE incorporates an implementation tool and checklists tailored to trial reports and trial protocols for which extenuating circumstances have resulted in important modifications to the intended study procedures. The checklists include 4 sections capturing extenuating circumstances, important modifications, responsible parties, and interim data analyses. Conclusions and Relevance CONSERVE offers an extension to CONSORT and SPIRIT that could improve the transparency, quality, and completeness of reporting important modifications to trials in extenuating circumstances such as COVID-19.

Inclusion and subsequent reporting of minority participants in clinical trials are critical for ensuring external validity and detecting differences among subgroups, however reports suggest that ongoing gaps persist. ClinicalTrials.gov began requiring the reporting of race/ethnicity information (if collected) during results submission for trials in April 2017. For this study, we downloaded and compared trial race/ethnicity information from ClinicalTrials.gov submitted before (N = 3540) and after (N = 3542) the requirement date. We found that 42.0% of pre-requirement trials compared to 91.4% of post-requirement trials reported race/ethnicity information in ClinicalTrials.gov ; 8.6% of post-requirement trials indicated race/ethnicity information was not collected. Use of NIH/U.S. Office of Management and Budget (OMB) classification categories was slightly higher in the post-requirement (77.1%) compared to pre-requirement (72.8%) samples. Additionally, we examined two 10% random samples of post-requirement trials – one with customized race/ethnicity reporting in ClinicalTrials.gov and the other with corresponding results publications available in PubMed. In the first random sample, 95.9% of customized categories included race information and 52.7% included ethnicity information. In the other random sample, 33.1% had a corresponding results publication, of which 62.4% reported race/ethnicity information in the publication. Among trials without published race/ethnicity information, 90.0% reported race/ethnicity information on ClinicalTrials.gov . This analysis demonstrates that the requirement has advanced public availability of information on the inclusion of minorities in research, but that further work remains to systematically ensure collection and complete reporting of race/ethnicity information.

IntroductionUsing the tenets underlying social identity theory and the theory of planned behavior, the current study compared the perceptions, attitudes, and behaviors of e-cigarette users that reported vaping as self-defining ("vapers") compared to users that denied vaping was central to their identity ("non-vapers").MethodSecondary analyses of data from the 2017-2018 California Student Tobacco Survey were utilized. A weighted, multivariable regression model (N = 82,217) compared the demographic characteristics, beliefs, and behaviors of vapers and non-vapers. A path analytic model examined whether norms and attitudes mediated the relationship between vaper identity and use behavior.ResultsSelf-identified sexual and/or gender minority youth were more likely to identify as vapers compared to heterosexual and cisgender respondents. Youth that identified as vapers viewed e-cigarette use as more normative, held more favorable attitudes (i.e., lower harm beliefs), used e-cigarettes more frequently and in greater quantities, were more likely to use fruit and mint flavored e-cigarettes, and were more likely to acquire e-cigarettes from commercial sellers (i.e., vape/tobacco shops; all p < 0.05). Additionally, descriptive norms and attitudes mediated the relationship between vaper identity and use frequency/quantity.ConclusionsDifferences in e-cigarette beliefs and behaviors were found for youth e-cigarette users that perceived vaping as self-defining versus those that did not view vaping as part of their self-concept. Future studies are needed to examine causal directionality between identity, norms, attitudes, and behavior. Tobacco control efforts might use these findings to further denormalize vaping using evidence-based media campaigns and policy implementation.

Purpose To examine the chemical composition of JUUL pods collected from a convenience sample of 16 high schools in California to identify possible consumer modification or counterfeit use. Methods Using Gas Chromatography–Mass Spectrometry, we quantitatively analyzed the nicotine, propylene glycol (PG), and vegetable glycerin (VG) in JUUL pods (n = 26) collected from California high schools and compared results to commercial 3% (n = 15) and 5% (n = 24) JUUL pods purchased online. Results Most of the collected JUUL pods (24/26 pods) had a nicotine concentration (43.3 mg/ml, 95% PI: 21.5–65.1) outside the prediction intervals (PI) of the 3% (33.5 mg/ml, 95% PI: 31.8–35.2) and 5% (55.0 mg/ml, 95% PI: 51.5–58.3) commercial JUUL pods. Most (73%) collected JUUL pods had VG concentrations (583.5 mg/ml, PI: 428.9–738.1) lower than the 3% (722.2 mg/ml, PI: 643.0–801.4) and 5% (710.5 mg/ml, PI: 653.1–767.8) commercial JUUL pods. Conclusions Used JUUL products collected from high school students or found on school grounds were not chemically consistent with the manufacturer’s stated formulations.

We present near-infrared observations of 42 gravitationally lensed galaxies obtained in the framework of the KMOS Lensed Emission Lines and VElocity Review (KLEVER) Survey, a program aimed at investigating the spatially resolved properties of the ionised gas in 1.2 3$\sigma$) "inverted" gradients are also found, showing an anti-correlation between metallicity and star formation rate density on local scales, possibly suggesting recent episodes of pristine gas accretion or strong radial flows in place. Nevertheless, the individual metallicity maps are characterised by a variety of different morphologies, with flat radial gradients sometimes hiding non-axisymmetric variations on kpc scales which are washed out by azimuthal averages, especially in interacting systems or in those undergoing local episodes of recent star formation., Comment: Main text: 23 pages, 11 figures. Appendix: 12 pages, 11 figures. Accepted for publication on MNRAS

The phenomenon of cortical thinning with age has been well established; however, the measured rate of change varies between studies. The source of this variation could be image acquisition techniques including hardware and vendor specific differences. Databases are often consolidated to increase the number of subjects but underlying differences between these datasets could have undesired effects. We explore differences in cerebral cortex thinning between 4 databases, totaling 1382 subjects. We investigate several aspects of these databases, including: 1) differences between databases of cortical thinning rates versus age, 2) correlation of cortical thinning rates between regions for each database, and 3) regression bootstrapping to determine the effect of the number of subjects included. We also examined the effect of different databases on age prediction modeling. Cortical thinning rates were significantly different between databases in all 68 parcellated regions (ANCOVA, P < 0.001). Subtle differences were observed in correlation matrices and bootstrapping convergence. Age prediction modeling using a leave-one-out cross-validation approach showed varying prediction performance (0.64 < R2 < 0.82) between databases. When a database was used to calibrate the model and then applied to another database, prediction performance consistently decreased. We conclude that there are indeed differences in the measured cortical thinning rates between these large-scale databases.

Polymeric core–shell micelles incorporating a chiral palladium pyridinooxazoline catalyst are presented as nanoreactors for the aqueous asymmetric synthesis of flavanones, a class of flavonoids with therapeutic properties. Use of the nanoreactor was found to increase catalyst activity, enabling catalysis at room temperature, with low palladium loadings and without any additives.

In the decade following the journal editors’ trial registration policy, a global trial reporting system (TRS) has arisen to supplement journal publication by increasing the transparency and accountability of the clinical research enterprise (CRE), which ultimately advances evidence-based medicine. Trial registration a foundation component of the TRS. In this article, we assess impact of the trial registration on the CRE with respect to two key goals: (1) establishing a publicly accessible and structured public record of all trials and (2) ensuring access to date-stamped protocol details that change during a study. After characterizing international trial registry landscape, we summarize the published evidence of the impact of the registration laws and policies on the CRE to date. We present three analyses using ClinicalTrials.gov registration data to illustrate approaches for assessing and monitoring the TRS: (1) timing of registration (i.e., prior to trial initiation [prospective] or after trial initiation [retrospective or “late”]; (2) degree of specificity and consistency of registered primary outcome measures compared to descriptions in study protocols and published articles; and (3) a survey of the published literature to characterize how ClinicalTrials.gov data has been used in research on the CRE. These findings suggest that, while the TRS is largely moving towards goals, key stakeholders need to do more in the next decade.

The final rule for reporting clinical trial results has now been issued by the Department of Health and Human Services. It aims to increase accountability in the clinical research enterprise, making key information available to researchers, funders, and the public.

Agriculture plays a key role in national economies and individual livelihoods in many developing countries, and yet agriculture as a field of study and an occupation remain under-emphasized in many educational systems. In addition, working in agriculture is often perceived as being less desirable than other fields, and not a viable or compelling option for students who have received a post-secondary education. This article explores the historical and contemporary perceptions of agriculture as a field of study and an occupation globally, and applies themes from the literature to analyze primary data from focus groups with international students studying for university degrees in the United States. The article analyzes students’ perceptions and experiences in four countries—Bangladesh, Nepal, Honduras and Haiti—in order to make recommendations about how best to address challenges and develop capacity in agricultural education and employment in low-income countries.

A novel fluorescent monomer was synthesized to probe the state of CO2-responsive cross-linked polymeric particles. The fluorescent emission of this aminobromomaleimide-bearing monomer, being sensitive to protic environments, can provide information on the core hydrophilicity of the particles and therefore indicates the swollen state and size of the particles. The particles’ core, synthesized from DEAEMA (N,N-diethylaminoethyl methacrylate), is responsive to CO2 through protonation of the tertiary amines of DEAEMA. The response is reversible and the fluorescence emission can be recovered by simply bubbling nitrogen into the particle solution. Alternate purges of CO2 and N2 into the particles’ solution allow several ON/OFF fluorescence emission cycles and simultaneous particle swelling/shrinking cycles.\ud \ud

Global efforts such as the Sustainable Development Goals recognize and underscore the significant role that human nutrition has on individual health and population-level development. Consequently, interdisciplinary and multi-stakeholder groups, such as the Global Alliance for Improving Nutrition and the Scaling Up Nutrition Movement, have been established to reduce under-nutrition, particularly in children and pregnant women. The concept of nutrition-sensitive agriculture has grown significantly in recent years, and the evidence indicates that integration of nutritional outcomes into agriculture programs has allowed these efforts to make important contributions to the reduction of malnutrition. However, when considering livestock as a subset of agricultural research and programming, nutritional objectives have been less effectively integrated into research and programming. The repercussions of this missed opportunity are exacerbated by the unique nutritional value of animal source foods (ASF) and its potential to increase dietary diversity and improve nutrition and health. Through a set of expert interviews with researchers and development practitioners in the areas of livestock and/or human nutrition, this article identifies factors that make livestock research and programs nutrition-sensitive and factors associated with livestock research/programs that fail to be nutrition-sensitive. Results indicate that an overly narrow focus on nutritional indicators, such as stunting, and target population (children) have hindered the uptake of nutrition-sensitive approaches. Experts indicate that interdisciplinary teams, longer and more iterative funding cycles, and integration of behavior change are elements livestock programs that successfully integrate nutrition. Implications of these and other findings for donors, researchers, and practitioners are presented.

OBJECTIVES: Little evidence is available on the association of e-cigarettes with health indices. We investigated the association of e-cigarette use with diagnosed respiratory disorder among adults with data from the Behavioral Risk Factor Surveillance Survey (BRFSS). METHODS: The 2016 Hawaii BRFSS, a cross-sectional random-dial telephone survey, had 8,087 participants; mean age was 55 years. Items asked about e-cigarette use, cigarette smoking, and being diagnosed by a health professional with (a) asthma or (b) chronic obstructive pulmonary disease. Multivariable analyses tested associations of e-cigarette use with the respiratory variables controlling for smoking and demographic, physical, and psychosocial variables. RESULTS: Controlling for the covariates and smoking there was a significant association of e-cigarette use with chronic pulmonary disorder in the total sample (AOR = 2.58, CI 1.36 – 4.89, p < .01) and a significant association with asthma among nonsmokers (AOR = 1.33, CI 1.00 – 1.77, p < .05). The associations were stronger among nonsmokers than among smokers. Results were similar for analyses based on relative risk and absolute risk. There was also a greater likelihood of respiratory disorder for smokers, females, and persons with overweight, financial stress, and secondhand smoke exposure. CONCLUSIONS: This is the first study to show a significant independent association of e-cigarette use with chronic respiratory disorder. Several aspects of the data are inconsistent with the possibility that e-cigarettes were being used for smoking cessation by persons with existing respiratory disorder. Theoretical mechanisms that might link e-cigarettes use and respiratory symptoms are discussed.

The physical properties of cyclic and linear polymers are markedly different; however, there are few examples which exploit these differences in clinical applications. In this study, we demonstrate that self-assemblies comprised of cyclic-linear graft copolymers are significantly more stable than the equivalent linear-linear graft copolymer assemblies. This difference in stability can be exploited to allow for triggered disassembly by cleavage of just a single bond within the cyclic polymer backbone , via disulfide reduction, in the presence of intracellular levels of l -glutathione. This topological effect was exploited to demonstrate the first example of topology-controlled particle disassembly for the controlled release of an anti-cancer drug in vitro . This approach represents a markedly different strategy for controlled release from polymer nanoparticles and highlights for the first time that a change in polymer topology can be used as a trigger in the design of delivery vehicles. We propose such constructs, which demonstrate disassembly behavior upon a change in polymer topology, could find application in the targeted delivery of therapeutic agents.

This chapter describes the evolving role of clinical trial registries and results databases. The first part describes the important public health policy goals of registration and results reporting, its history, and key policies in the United States and abroad. The second part focuses on practical issues, policies, and procedures for submitting data to and using data from ClinicalTrials.gov , the largest publicly available clinical trials database in the world. The future role of systematic sharing of individual participant data also is discussed.

Nature is capable of synthesizing perfectly defined, sequence-controlled oligomers and polymers, whereas synthetic polymerization methods inherently give rise to dispersity and limited reproducibility. This inherent dispersity provides a barrier to translation into biomedical applications and for probing material-biology interactions. Templating of polymers based upon biosynthesized cores offers a route to reproducible oligo/polymers if the template itself is readily available and highly tunable. Here oligosaccharides are employed as monodisperse scaffolds for the synthesis of highly functional biomaterials. The pendant hydroxyl units are converted to reactive methacrylates, which are themselves amenable for thiol-ene (‘click’) functionalization. Using this strategy, extremely well defined (MW/MN < 1.05) polymers are prepared bearing thermoresponsive or lectin-binding moieties. The templatation strategy ensures identical polymers are obtained from each synthesis. Their thermoresponsive behavior and multivalent interactions with a bacterial lectin are studied as a function of the discrete number of functional groups. Due to the ester linkage, these polymers are also shown to be inherently degradable.

OBJECTIVE To describe electronic cigarette (e-cigarette) use and cigarette use among adolescents abstract and determine whether established risk factors for smoking discriminate user categories. METHODS School-based survey of 1941 high school students (mean age 14.6 years) in Hawaii; data collected in 2013. The survey assessed e-cigarette use and cigarette use, alcohol and marijuana use, and psychosocial risk and protective variables (eg, parental support, academic involvement, smoking expectancies, peer smoking, sensation seeking). Analysis of variance and multinomial regression examined variation in risk and protective variables across the following categories of ever-use: e-cigarette only, cigarette only, dual use (use of both products), and nonuser (never used either product). RESULTS Prevalence for the categories was 17% (e-cigarettes only), 12% (dual use), 3% (cigarettes only), and 68% (nonusers). Dual users and cigarette-only users were highest on risk status (elevated on risk factors and lower on protective factors) compared with other groups. E-cigarette only users were higher on risk status than nonusers but lower than dual users. E-cigarette only users and dual users more often perceived e-cigarettes as healthier than cigarettes compared with nonusers. CONCLUSIONS This study reports a US adolescent sample with one of the largest prevalence rates of e-cigarette only use in the existing literature. Dual use also had a substantial prevalence. The fact that e-cigarette only users were intermediate in risk status between nonusers and dual users raises the possibility that e-cigarettes are recruiting medium-risk adolescents, who otherwise would be less susceptible to tobacco product use.

A new method is proposed for obtaining cerebral perfusion measurements whereby blood oxygen level dependent (BOLD) MRI is used to dynamically monitor hyperoxia-induced changes in the concentration of deoxygenated hemoglobin in the cerebral vasculature. The data is processed using kinetic modeling to yield perfusion metrics, namely: cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT). Ten healthy human subjects were continuously imaged with BOLD sequence while a hyperoxic (70% O2) state was interspersed with baseline periods of normoxia. The BOLD time courses were fit with exponential uptake and decay curves and a biophysical model of the BOLD signal was used to estimate oxygen concentration functions. The arterial input function was derived from end-tidal oxygen measurements, and a deconvolution operation between the tissue and arterial concentration functions was used to yield CBF. The venous component of the CBV was calculated from the ratio of the integrals of the estimated tissue and arterial concentration functions. Mean gray and white matter measurements were found to be: 61.6 ± 13.7 and 24.9 ± 4.0 ml 100 g−1 min−1 for CBF; 1.83 ± 0.32 and 1.10 ± 0.19 ml 100 g−1 for venous CBV; and 2.94 ± 0.52 and 3.73 ± 0.60 s for MTT, respectively. We conclude that it is possible to derive CBF, CBV and MTT metrics within expected physiological ranges via analysis of dynamic BOLD fMRI acquired during a period of hyperoxia.

Cerebral amyloid angiopathy (CAA) is a small-vessel disease preferentially affecting posterior brain regions. Recent evidence has demonstrated the efficacy of functional MRI in detecting CAA-related neurovascular injury, however, it is unknown whether such perturbations are associated with changes in the hemodynamic response function (HRF). Here we estimated HRFs from two different brain regions from block design activation data, in light of recent findings demonstrating how block designs can accurately reflect HRF parameter estimates while maximizing signal detection. Patients with a diagnosis of probable CAA and healthy controls performed motor and visual stimulation tasks. Time-to-peak (TTP), full-width at half-maximum (FWHM), and area under the curve (AUC) of the estimated HRFs were compared between groups and to MRI features associated with CAA including cerebral microbleed (CMB) count. Motor HRFs in CAA patients showed significantly wider FWHM ( P = 0.006) and delayed TTP ( P = 0.03) compared to controls. In the patient group, visual HRF FWHM was positively associated with CMB count ( P = 0.03). These findings indicate that hemodynamic abnormalities in patients with CAA may be reflected in HRFs estimated from block designs across different brain regions. Moreover, visual FWHM may be linked to structural MR indications associated with CAA.

Conclusion: Alpha B-crystallin was found to be an independent prognostic marker for poor prognosis in oral cavity tumours. For oropharyngeal cancer, alpha B-crystallin had no prognostic value. Objective: The aim of this study was to see if earlier findings of alpha B-crystallin as an independent prognostic marker, and SPARC/osteonectin, PAI-1 and uPA as a prognostic combination for poor outcome in squamous cell carcinoma (SCC) of the head and neck could be confirmed in a new set of tumours. Methods: In a consecutive series of patients, assessed and primarily treated at a tertiary referral centre, histological sections from 55 patients with oral and SCC (OOPHSSC) with complete clinical data and follow-up were obtained. Oral and oropharyngeal tumours were studied separately. Immunohistochemical detection of alpha B-crystallin, SPARC/osteonectin, PAI-1 and uPA expression was performed. Results: Thirty-five patients had an oral tumour and 20 patients an oropharyngeal tumour. Twenty-five oral tumours stained negatively and 10 positively for alpha B-crystallin. For oropharyngeal tumours the figures were 15 negatively and 5 positively. Median disease-specific survival (DSS) for both sites was 33.8 and 11.9 months, for negative and positive alpha B-crystallin staining, respectively (p = 0.046). For the oral cavity, median DSS was 27.3 months for negative tumours and 7.5 months for positive tumours (p = 0.012). Corresponding figures for oropharyngeal tumours were 33.8 and 34.1 months (p = 0.95). Thus, significance in survival was only found in oral cavity tumours. In multivariate analyses there were no significant differences in DSS in the oropharyngeal group when adjusted for tumour size (T status) and presence of neck node metastasis (N status). In the oral cavity group, the significantly better DSS for negative tumours became even stronger when adjusted for T and N status. No statistical difference was found in DSS between positive and negative staining for SPARC/osteonectin, PAI-1 or uPA.

Smoking remains the leading cause of preventable death in the United States. Although healthcare workers play a key role in helping patients quit smoking, the degree to which they provide help varies. This study assesses the extent to which smokers report that their healthcare worker advised and assisted them with quitting based on their level of readiness to make a change. The 2006 Hawaii Adult Tobacco Survey asked questions regarding smoking status and if advice and assistance with quitting was given from a healthcare worker. Percentages for reporting healthcare worker's advice and assistance were compared among the three levels of motivational readiness using the chi-square test of association for 331 current, everyday smokers (56% women; 38% in the age group of 45-54 years). Most smokers are given advice to quit smoking. However, only about half of those motivated to quit are given assistance to do so. Most smokers across all motivation levels received advice to quit smoking with no significant difference between levels of readiness to quit. Less than half of smokers received any type of assistance with quitting smoking, with higher motivated smokers significantly receiving more assistance with cessation medication or nicotine replacement therapy and setting a quit date. This is a call to action for healthcare workers to address smoking with every patient. Adjustments to protocols for addressing smoking cessation and readiness to quit may be warranted.

PURPOSE To compare diffusion-weighted functional magnetic resonance imaging (DfMRI), a novel alternative to the blood oxygenation level-dependent (BOLD) contrast, in a functional MRI experiment. MATERIALS AND METHODS Nine participants viewed contrast reversing (7.5 Hz) black-and-white checkerboard stimuli using block and event-related paradigms. DfMRI (b = 1800 mm/s2 ) and BOLD sequences were acquired. Four parameters describing the observed signal were assessed: percent signal change, spatial extent of the activation, the Euclidean distance between peak voxel locations, and the time-to-peak of the best fitting impulse response for different paradigms and sequences. RESULTS The BOLD conditions showed a higher percent signal change relative to DfMRI; however, event-related DfMRI showed the strongest group activation (t = 21.23, P < 0.0005). Activation was more diffuse and spatially closer to the BOLD response for DfMRI when the block design was used. DfMRIevent showed the shortest TTP (4.4 +/- 0.88 sec). CONCLUSION The hemodynamic contribution to DfMRI may increase with the use of block designs.

Reliance on the hemodynamic response as a surrogate marker of neural activity imposes an intrinsic limit on the spatial specificity of functional MRI. An alternative approach based on diffusion-weighted functional MRI (DfMRI) has been reported as a contrast less reliant on hemodynamic effects, however current evidence suggests that both hemodynamic and unique neural sources contribute to the diffusion signal. Here we compare activation patterns obtained with the standard blood oxygenation level-dependent (BOLD) contrast to DfMRI in order to gain a deeper understanding of how the BOLD proportion contributes to the observable diffusion signal. Both individual and group-level activation patterns obtained with DfMRI and BOLD to a visual field stimulation paradigm were analyzed. At the individual level, the DfMRI contrast showed a strong, positive relationship between the volumes of cortex activated in response to quadrant- and hemi-field visual stimulation. This was not observed in the corresponding BOLD experiment. Overall, the DfMRI response indicated less between-subject variability, with random effects analyses demonstrating higher statistical values at the peak voxel for DfMRI. Furthermore, the spatial extent of the activation was more restricted to the primary visual region for DfMRI than BOLD. However, the diffusion signal was sensitive to the hemodynamic response in a manner dependent on experimental manipulation. It was also limited by its low signal-to-noise ratio (SNR), demonstrating lower sensitivity than BOLD. Together these findings both support DfMRI as a contrast that bears a closer spatial relationship to the underlying neural activity than BOLD, and raise important caveats regarding its utilization. Models explaining the DfMRI signal change need to consider the dynamic vascular contributions that may vary with neural activity.