Chiral orbital-angular-momentum in the surface states of Bi2Se3

Locking of the spin of a quasi-particle to its momentum in split bands of on the surfaces of metals and topological insulators (TIs) is understood in terms of Rashba effect where a free electron in the surface states feels an effective magnetic field. On the other hand, the orbital part of the angular momentum (OAM) is usually neglected. We performed angle resolved photoemission experiments with circularly polarized lights and first principles density functional calculation with spin-orbit coupling on a TI, Bi2Se3, to study the local OAM of the surface states. We show from the results that OAM in the surface states of Bi2Se3 is significant and locked to the electron momentum in opposite direction to the spin, forming chiral OAM states. Our finding opens a new possibility to have strong light-induced spin-polarized current in the surface states.Comment: 5 pages, 4 figures, 1 tabl

Circulating markers of microbial translocation and host response to bacteria with risk of colorectal cancer: A prospective, nested case-control study in men

BACKGROUND: Gut microbial dysbiosis contributes to colorectal cancer (CRC) pathogenesis, possibly mediated in part by increased intestinal permeability to endotoxin lipopolysaccharide (LPS), microbial translocation, and subsequent endotoxemia and inflammation. However, epidemiologic evidence linking circulating markers of microbial translocation with CRC risk is limited. METHODS: We conducted a prospective, nested case-control study of 261 incident CRC cases and 261 controls (matched on age and time of blood draw) among 18,159 men with pre-diagnostic blood specimens in the Health Professionals Follow-Up Study (1993-2009). We examined three complementary markers of microbial translocation and host response to bacteria, including LPS-binding protein (LBP), soluble CD14 (sCD14), and endotoxincore antibody (EndoCAb) immunoglobulin M (IgM), with subsequent risk of CRC. Unconditional logistic regressions were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). FINDINGS: Pre-diagnostic circulating levels of sCD14 were associated with a higher risk of incident CRC. Compared to men in the lowest quartile, the multivariable OR was 1.90 (95% CI, 1.13-3.22) for men in the highest quartile (OR INTERPRETATION: Microbial translocation and host response to bacteria, as reflected by sCD14, is associated with risk of incident CRC in men. FUNDING: US National Institutes of Health

The Sulfur Microbial Diet Is Associated With Increased Risk of Early-Onset Colorectal Cancer Precursors

Background & Aims: Diet may contribute to the increasing incidence of colorectal cancer (CRC) before age 50 (early-onset CRC). Microbial metabolism of dietary sulfur produces hydrogen sulfide (H2S), a gastrointestinal carcinogen that cannot be easily measured at scale. As a result, evidence supporting its role in early neoplasia is lacking. Methods: We evaluated long-term adherence to the sulfur microbial diet, a dietary index defined a priori based on increased abundance of 43 bacterial species involved with sulfur metabolism, with risk of CRC precursors among 59,013 individuals who underwent lower endoscopy in the Nurses’ Health Study II (1991–2015), a prospective cohort study with dietary assessment every 4 years through validated food frequency questionnaires and an assessment of dietary intake during adolescence in 1998. The sulfur microbial diet was characterized by intake high in processed meats, foods previously linked to CRC development, and low in mixed vegetables and legumes. Multivariable logistic regression for clustered data was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs). Results: We documented 2911 cases of early-onset adenoma. After adjusting for established risk factors, higher sulfur microbial diet scores were associated with increased risk for early-onset adenomas (ORquartile [Q]4 vs Q1, 1.31; 95% CI, 1.10–1.56, Ptrend = .02), but not serrated lesions. Compared with the lowest, women in the highest quartile of sulfur microbial diet scores had significantly increased risk of early-onset adenomas with greater malignant potential (ORQ4 vs Q1, 1.65 for villous/tubulovillous histology; 95% CI, 1.12–2.43; Ptrend = .04). Similar trends for early-onset adenoma were observed based on diet consumed during adolescence. In contrast, no clear association for adenomas was identified after age 50. Conclusions: Our findings in a cohort of young women support a role for dietary interactions with gut sulfur-metabolizing bacteria in early-onset colorectal carcinogenesis, possibly beginning in adolescence. Includes Supplemental materials

The relation of teacher instruction and classroom environment to children\u27s letter knowledge

Children\u27s letter knowledge is a strong predictor of later reading ability. However, there is limited research information on the relation of early childhood teacher instruction and classroom literacy environment to children\u27s letter knowledge. The current study examined: 1) associations among teachers\u27 explicit instruction in letter knowledge across three activity contexts (book reading, other large group activities, and free play period) and the literacy environment, 2) the relation between overall letter knowledge exposure (teacher instruction and literacy environment) and children\u27s letter knowledge growth across one semester, and 3) possible unique contributions of teachers\u27 explicit instruction in letter knowledge and the classroom literacy environment to growth in children\u27s letter knowledge. The sample included 31 Head Start teachers/classrooms and their 262 children. The results revealed that teachers\u27 explicit instruction during book reading and other large group activities were significantly related. The association between overall letter knowledge exposure and children\u27s letter knowledge growth demonstrated that the literacy environment and teachers\u27 explicit instruction did not work together to promote children\u27s letter knowledge. Neither teachers\u27 explicit instruction in letter knowledge nor the classroom literacy environment was uniquely associated with growth of children\u27s letter knowledge. Results suggest that teachers\u27 explicit instruction and the classroom literacy environment compensate each other in supporting children\u27s letter knowledge

Nutritional Determinants of Pubertal Development of Girls in Rural Bangladesh

This doctoral dissertation investigated the usual patterns of pubertal development and nutritional determinants of timing of menarche of girls in rural South Asia. A prospective, population-based cohort study of adolescent girls was conducted in rural Gaibandha District in Bangladesh between 2015 and 2017. At an initial (baseline) home visit, 15,325 girls aged 9-15 years were recruited and assessed, of whom 14,061 girls (91.8%) were followed approximately one year later. Three aspects of pubertal development were assessed: the timing of menarche, serving as the primary sexual characteristic of focal research interest, supplemented by ages of appearance of the secondary sexual characteristics of breast development and pubic hair growth. For menarche, girls were initially asked to recall the calendar year and month of their first menstruation; at follow-up, the same question was repeated. For breast development and pubic hair growth, at both visits, a self-reported questionnaire adapted from the Pubertal Development Scale (PDS) was independently administered and locally adapted to categorize girls into maturational stages corresponding to Tanner’s Sexual Maturation Scale. Anthropometric status (height, weight and mid-upper arm circumference) was measured at baseline and follow-up visits. Three 7-day food frequencies were assessed across the interim year. With the use of the probit regression, median ages at the onset of the pubertal milestones were calculated. The risk of subsequent 1-year incidence in menarche by nutritional status, as reflected by attained body size at baseline and interim growth velocities, and interim dietary intake was computed as hazard ratios (HRs) from multivariate Cox proportional hazards models. The median (95% confidence interval, CI) age at menarche was 13.17 (13.15-13.19) years. The median (95% CI) age for stages 2 and 3-4 for breast development was 11.02 (11.00-11.04) and 12.82 (12.80-12.83) years, respectively; for pubic hair growth, the age for each respective stage category was 12.93 (12.91-12.94) and 14.29 (14.27-14.31) years. At baseline, menarcheal girls were taller and had higher body mass index (BMI) than their premenarcheal peers of same age. Girls who were premenarcheal at baseline were 13% (HR=1.13, 95% CI 1.12-1.14) and 29% (HR=1.29, 95% CI 1.26-1.33) more likely to attain menarche in the following year per attained cm in height and kg/m² in BMI, respectively. Effect sizes decreased with age. Interim velocities in linear growth (per cm/year) and BMI gain (kg/m²/year) were positively associated with reporting first menstruation by follow-up among girls who were 10 and 11-13 years of age at baseline, respectively; not at older ages. Among initially premenarcheal girls, dietary intake during the interim year was associated with having reported menarche by follow-up. Specifically, mean weekly intake frequencies above the 3rd tertile cutoff for eggs, milk and dairy products and other beverages (tea and sweetened drinks) were associated with 12% (HR=1.12, 95% CI 1.02-1.23), 13% (HR=1.13, 95% CI 1.04-1.24) and 17% (HR=1.17, 95% CI 1.08-1.27) higher likelihood of being postmenarcheal by follow-up compared to intake frequencies in the 1st third for each food group. The observed associations were, however, attenuated toward the null after accounting for socioeconomic factors. On the other hand, irrespective of socioeconomic status, mean intake frequencies in the upper third for fish and seafood and sweets were associated with 11% (HR=0.89, 95% CI 0.81-0.98) and 20% (HR=0.80, 95% CI 0.73-0.88) lower likelihood of reporting menarche in the interim year, respectively, compared to intake frequencies in the lowest third. Attained size and faster growth velocities in height and BMI were associated with earlier occurrence of menarche in rural Bangladeshi girls, most evident at younger ages. Consumption of animal source foods was associated with earlier onset of menarche and, paradoxically, fish and seafood intakes with later menarche. In contemporary rural Bangladesh, better nourished girls, as reflected by their larger body size, faster growth velocity and increased consumption of animal source foods, before accounting for socioeconomic status for the latter, attained earlier menarche than their less well-nourished peers, possibly due to their advanced biological maturity. Future studies that can illuminate biological plausibility of these associations with the extended follow-up period will help better understand adolescent pubertal growth and maturation which to base interventions of public health importance in this region of priority

Circulating markers of microbial translocation and host response to bacteria with risk of colorectal cancer: a prospective, nested case-control study in men

BackgroundGut microbial dysbiosis contributes to colorectal cancer (CRC) pathogenesis, possibly mediated in part by increased intestinal permeability to endotoxin lipopolysaccharide (LPS), microbial translocation, and subsequent endotoxemia and inflammation. However, epidemiologic evidence linking circulating markers of microbial translocation with CRC risk is limited.MethodsWe conducted a prospective, nested case-control study of 261 incident CRC cases and 261 controls (matched on age and time of blood draw) among 18,159 men with pre-diagnostic blood specimens in the Health Professionals Follow-Up Study (1993-2009). We examined three complementary markers of microbial translocation and host response to bacteria, including LPS-binding protein (LBP), soluble CD14 (sCD14), and endotoxincore antibody (EndoCAb) immunoglobulin M (IgM), with subsequent risk of CRC. Unconditional logistic regressions were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).FindingsPre-diagnostic circulating levels of sCD14 were associated with a higher risk of incident CRC. Compared to men in the lowest quartile, the multivariable OR was 1.90 (95% CI, 1.13-3.22) for men in the highest quartile (OR per standard deviation [SD] increase, 1.28; 95%CI 1.06-1.53; Ptrend = 0.01). This positive association remained similar after adjusting for C-reactive protein, interleukin-6, and soluble tumor necrosis factor receptor-2, and within strata of putative CRC risk factors. We also observed a suggestive inverse association between EndoCAb IgM and risk of CRC (OR per SD increase, 0.84; 95%CI 0.69-1.02; Ptrend = 0.09).InterpretationMicrobial translocation and host response to bacteria, as reflected by sCD14, is associated with risk of incident CRC in men.FundingUS National Institutes of Health

Pathways to Security: Closing Gaps in Protection for Forced Migrants

Created as part of the 2014 Jackson School for International Studies SIS 495: Task Force. Kathie Friedman, Task Force Advisor; Jeff Crisp, Evaluator; Quincy Hernan, Louisa Johnson and Clara Langevin, Coordinator.This report focuses on three primary themes within the international refugee regime and identifies gaps in protection for Convention as well as non-Convention forced migrants. The first, solidarity, refers to the uneven cooperation present in the refugee regime through international, national and local levels. Secondly, lack of access to information regarding the Refugee Status Determination (RSD) process and allocation of amenities. Lastly, the problem of documentation will be presented due to its importance for the consolidation of status, rights, and privileges of refugees. These themes will address concerns for various populations of refugees and forced migrants in particular urban refugees, camp refugees, and forced migrants not protected under the 1951 Convention

Nanostructured graphene/Fe3O4 incorporated polyaniline as a high performance shield against electromagnetic pollution

The development of high-performance shielding materials against electromagnetic pollution requires mobile charge carriers and magnetic dipoles. Herein, we meet the challenge by building a three-dimensional (3D) nanostructure consisting of chemically modified graphene/Fe3O4(GF) incorporated polyaniline. Intercalated GF was synthesized by the in situ generation of Fe3O4 nanoparticles in a graphene oxide suspension followed by hydrazine reduction, and further in situ polymerization with aniline to form a polyaniline composite. Spectroscopic analysis demonstrates that the presence of GF hybrid structures facilitates strong polarization due to the formation of a solid-state charge-transfer complex between graphene and polyaniline. This provides proper impedance matching and higher dipole interaction, which leads to the high microwave absorption properties. The higher dielectric loss (epsilon '' = 30) and magnetic loss (mu '' = 0.2) contribute to the microwave absorption value of 26 dB (>99.7% attenuation), which was found to depend on the concentration of GF in the polyaniline matrix. Moreover, the interactions between Fe3O4, graphene and polyaniline are responsible for superior material characteristics, such as excellent environmental (chemical and thermal) degradation stability and good electric conductivity

Sugar-sweetened beverage and sugar consumption and colorectal cancer incidence and mortality according to anatomic subsite

Background Recent preclinical research strongly suggests that dietary sugars can enhance colorectal tumorigenesis by direct action, particularly in the proximal colon that unabsorbed fructose reaches. Objectives We aimed to examine long-term consumption of sugar-sweetened beverages (SSBs) and total fructose in relation to incidence and mortality of colorectal cancer (CRC) by anatomic subsite. Methods We followed 121,111 participants from 2 prospective US cohort studies, the Nurses' Health Study (1984-2014) and Health Professionals Follow-Up Study (1986-2014), for incident CRC and related death. Cox proportional hazards regression was used to compute HRs and 95% CIs. Results During follow-up, we documented 2733 incident cases of CRC with a known anatomic location, of whom 901 died from CRC. Positive associations of SSB and total fructose intakes with cancer incidence and mortality were observed in the proximal colon but not in the distal colon or rectum (P-heterogeneity <= 0.03). SSB consumption was associated with a statistically significant increase in the incidence of proximal colon cancer (HR per 1-serving/d increment: 1.18; 95% CI: 1.03, 1.34; P-trend = 0.02) and a more pronounced elevation in the mortality of proximal colon cancer (HR: 1.39; 95% CI: 1.13, 1.72; P-trend = 0.002). Similarly, total fructose intake was associated with increased incidence and mortality of proximal colon cancer (HRs per 25-g/d increment: 1.18; 95% CI: 1.03, 1.35; and 1.42; 95% CI: 1.12, 1.79, respectively). Moreover, SSB and total fructose intakes during the most recent 10 y, rather than those from a more distant period, were associated with increased incidence of proximal colon cancer. Conclusions SSB and total fructose consumption were associated with increased incidence and mortality of proximal colon cancer, particularly during later stages of tumorigenesis.N