A macroscopic yield criterion for crystalline polymers

Yield studies including uniaxial tension, uniaxial compression and biaxial stress states (developed with internally pressurized thin wall tubes) were conducted with high density polyethylene. The experimental results are compared with a predicted yield locus based upon a pressure-modified von Mises criterion. Agreement was quite reasonable although a slight degree of anisotropy was noted in the test material. Since this same yield criterion has earlier been shown to provide excellent agreement with glassy amorphous polymers it appears unnecessary to employ different criteria for different polymers if one is concerned with macroscopic yielding.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33777/1/0000030.pd

Yield locus studies of oriented polycarbonate An anisotropic and pressure-dependent solid

Uniaxial and biaxial stress states were employed so as to investigate the yield behavior of oriented polycarbonate. These experimental results are compared with a theoretical yield locus based upon a yield criterion proposed for solids that are both anisotropic and pressure dependent in regard to macroscopic yield behavior. A good correlation between theory and experiment was found.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22244/1/0000680.pd

Occupational stress and burnout among young surgeons: a review

A surgeon's lifestyle is a multifaceted commitment that revolves around their workplace, physical, personal, emotional, and communal domains. Surgical training programs are competitive and challenging to match and provide a sense of gratification among medical school trainees. But they also report a much higher level of burnout when compared to their peers from other specialities. Workplace burnout has been a scorching issue since the COVID pandemic broke out in 2019. We did this review to understand the factors leading to workplace burnout, identify any East-West differences, and find possible solutions. We also tried to find the role of COVID-19 in worsening occupational stress among surgeons. We searched the PubMed and SCOPUS databases for studies between January 2000 to January 2022 on burnout, well-being, wellness, and practice improvement among surgeons. The search included studies on COVID-19 that were available either as full-text papers or abstracts. Burnout has affected younger surgeons owing to loss of professional control, inefficient work-life balance, administrative burdens, medico-legal problems, and the competitive nature of the job and tiresome training programs. Burnout is more common in South-Asian countries. Workplace stressors, including long hours and difficult interactions with co-workers, are linked to greater levels of burnout. The COVID-19 pandemic has only made matters worse

A yield criterion for anisotropic and pressure dependent solids such as oriented polymers

The anisotropic yield criterion first posed by Hill has been modified to account for differences in tensile and compressive yield strengths in a given direction; additionally, the influence of hydrostatic pressure on yielding is also considered. Predictions using this new criterion are compared with published experimental results involving oriented polymers and excellent agreement is found. It is suggested that this criterion is more correct on fundamental grounds than those put forth in earlier publications.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44783/1/10853_2004_Article_BF00754900.pd

The macroscopic yield behaviour of polymers

A yield criterion, not previously compared with the actual macroscopic behaviour of polymers, is herein compared with the pressure-modified octahedral shear stress criterion earlier suggested by others. This new relation, which is a version of the von Mises criterion, accommodates differences in tensile and compressive yield strengths and accounts for any dependence of yielding on the hydrostatic component of the applied stress state.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44784/1/10853_2004_Article_BF00550671.pd

Early Life Child Micronutrient Status, Maternal Reasoning, and a Nurturing Household Environment have Persistent Influences on Child Cognitive Development at Age 5 years : Results from MAL-ED

Funding Information: The Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development Project (MAL-ED) is carried out as a collaborative project supported by the Bill & Melinda Gates Foundation, the Foundation for the NIH, and the National Institutes of Health/Fogarty International Center. This work was also supported by the Fogarty International Center, National Institutes of Health (D43-TW009359 to ETR). Author disclosures: BJJM, SAR, LEC, LLP, JCS, BK, RR, RS, ES, LB, ZR, AM, RS, BN, SH, MR, RO, ETR, and LEM-K, no conflicts of interest. Supplemental Tables 1–5 and Supplemental Figures 1–3 are available from the “Supplementary data” link in the online posting of the article and from the same link in the online table of contents at https://academic.oup.com/jn/. Address correspondence to LEM-K (e-mail: [email protected]). Abbreviations used: HOME, Home Observation for Measurement of the Environment inventory; MAL-ED, The Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development Project; TfR, transferrin receptor; WPPSI, Wechsler Preschool Primary Scales of Intelligence.Peer reviewe

Early life child micronutrient status, maternal reasoning, and a nurturing household environment have persistent influences on child cognitive development at age 5 years: Results from MAL-ED

Background: Child cognitive development is influenced by early-life insults and protective factors. To what extent these factors have a long-term legacy on child development and hence fulfillment of cognitive potential is unknown. Objective: The aim of this study was to examine the relation between early-life factors (birth to 2 y) and cognitive development at 5 y. Methods: Observational follow-up visits were made of children at 5 y, previously enrolled in the community-based MAL-ED longitudinal cohort. The burden of enteropathogens, prevalence of illness, complementary diet intake, micronutrient status, and household and maternal factors from birth to 2 y were extensively measured and their relation with the Wechsler Preschool Primary Scales of Intelligence at 5 y was examined through use of linear regression. Results: Cognitive T-scores from 813 of 1198 (68%) children were examined and 5 variables had significant associations in multivariable models: mean child plasma transferrin receptor concentration (β: −1.81, 95% CI: −2.75, −0.86), number of years of maternal education (β: 0.27, 95% CI: 0.08, 0.45), maternal cognitive reasoning score (β: 0.09, 95% CI: 0.03, 0.15), household assets score (β: 0.64, 95% CI: 0.24, 1.04), and HOME child cleanliness factor (β: 0.60, 95% CI: 0.05, 1.15). In multivariable models, the mean rate of enteropathogen detections, burden of illness, and complementary food intakes between birth and 2 y were not significantly related to 5-y cognition. Conclusions: A nurturing home context in terms of a healthy/clean environment and household wealth, provision of adequate micronutrients, maternal education, and cognitive reasoning have a strong and persistent influence on child cognitive development. Efforts addressing aspects of poverty around micronutrient status, nurturing caregiving, and enabling home environments are likely to have lasting positive impacts on child cognitive development.publishedVersio

Macroscopic yielding behavior of polymeric materials

http://deepblue.lib.umich.edu/bitstream/2027.42/7199/5/bad1125.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/7199/4/bad1125.0001.001.tx

Amorphous structure heat: Molecular mechanisms from solution heats of poly(2,6‐dimethyl‐p‐phenylene oxide) in orthodichlorobenzene

The heats of solution in orthodichlorobenzene were measured as a function of temperature for both quenched and as‐received polyphenylene oxide. The curves are linear below 110°C with slopes of 0.098 cal∕g°C and linear above 110°C with slopes of 0.032 cal∕g°C. The inflection at 110°C is attributed to a β transition. The plot for the as‐received material is displaced vertically from that of the quenched material by 2.75 cal∕g which is attributed to the fact that the as‐received material contains about 27.5% crystallinity. The major component of the heats of solution is the exothermic contribution from the solvent‐induced freeing or relaxation of the constrained molecular motions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70773/2/JAPIAU-45-10-4151-1.pd