1,763 research outputs found
NASA automatic subject analysis technique for extracting retrievable multi-terms (NASA TERM) system
Current methods for information processing and retrieval used at the NASA Scientific and Technical Information Facility are reviewed. A more cost effective computer aided indexing system is proposed which automatically generates print terms (phrases) from the natural text. Satisfactory print terms can be generated in a primarily automatic manner to produce a thesaurus (NASA TERMS) which extends all the mappings presently applied by indexers, specifies the worth of each posting term in the thesaurus, and indicates the areas of use of the thesaurus entry phrase. These print terms enable the computer to determine which of several terms in a hierarchy is desirable and to differentiate ambiguous terms. Steps in the NASA TERMS algorithm are discussed and the processing of surrogate entry phrases is demonstrated using four previously manually indexed STAR abstracts for comparison. The simulation shows phrase isolation, text phrase reduction, NASA terms selection, and RECON display
Conscientiousness, hair cortisol concentration, and health behaviour in older men and women
Conscientious is associated with greater longevity and other favourable health outcomes, but the processes underlying these links are poorly understood. Health behaviours such as physical activity and avoidance of smoking and excessive alcohol consumption may contribute, but direct associations with neuroendocrine and inflammatory processes may also be relevant. We tested the associations between conscientiousness and hair cortisol concentration in 2318 older men and women (mean age 66.2 years) from the English Longitudinal Study of Ageing. Conscientiousness was positively associated with physical activity and fruit and vegetable consumption, and negatively related to alcohol intake, sedentary behaviour, body mass index and depressive symptoms (all p<0.001). We found an inverse association between conscientiousness and hair cortisol concentration that was independent of age, sex, education and wealth (β=-0.053, p=0.012), and the relationship remained significant with additional adjustment for health behaviour and depressive symptoms (β=-0.048, p=0.025). The observation that greater conscientiousness was correlated with lower hair cortisol indicates that this trait might impact central nervous regulation of hypothalamic-pituitary-adrenocortical function, with effects that are possibly advantageous for health
Single electron-phonon interaction in a suspended quantum dot phonon cavity
An electron-phonon cavity consisting of a quantum dot embedded in a
free-standing GaAs/AlGaAs membrane is characterized in Coulomb blockade
measurements at low temperatures. We find a complete suppression of single
electron tunneling around zero bias leading to the formation of an energy gap
in the transport spectrum. The observed effect is induced by the excitation of
a localized phonon mode confined in the cavity. This phonon blockade of
transport is lifted at magnetic fields where higher electronic states with
nonzero angular momentum are brought into resonance with the phonon energy.Comment: 4 pages, 4 figure
Remote participation during glycosylation reactions of galactose building blocks: Direct evidence from cryogenic vibrational spectroscopy
The stereoselective formation of 1,2‐cis‐glycosidic bonds is challenging. However, 1,2‐cis‐selectivity can be induced by remote participation of C4 or C6 ester groups. Reactions involving remote participation are believed to proceed via a key ionic intermediate, the glycosyl cation. Although mechanistic pathways were postulated many years ago, the structure of the reaction intermediates remained elusive owing to their short‐lived nature. Herein, we unravel the structure of glycosyl cations involved in remote participation reactions via cryogenic vibrational spectroscopy and first principles theory. Acetyl groups at C4 ensure α‐selective galactosylations by forming a covalent bond to the anomeric carbon in dioxolenium‐type ions. Unexpectedly, also benzyl ether protecting groups can engage in remote participation and promote the stereoselective formation of 1,2‐cis‐glycosidic bonds
Cortisol patterns are associated with T cell activation in HIV.
ObjectiveThe level of T cell activation in untreated HIV disease is strongly and independently associated with risk of immunologic and clinical progression. The factors that influence the level of activation, however, are not fully defined. Since endogenous glucocorticoids are important in regulating inflammation, we sought to determine whether less optimal diurnal cortisol patterns are associated with greater T cell activation.MethodsWe studied 128 HIV-infected adults who were not on treatment and had a CD4(+) T cell count above 250 cells/µl. We assessed T cell activation by CD38 expression using flow cytometry, and diurnal cortisol was assessed with salivary measurements.ResultsLower waking cortisol levels correlated with greater T cell immune activation, measured by CD38 mean fluorescent intensity, on CD4(+) T cells (r = -0.26, p = 0.006). Participants with lower waking cortisol also showed a trend toward greater activation on CD8(+) T cells (r = -0.17, p = 0.08). A greater diurnal decline in cortisol, usually considered a healthy pattern, correlated with less CD4(+) (r = 0.24, p = 0.018) and CD8(+) (r = 0.24, p = 0.017) activation.ConclusionsThese data suggest that the hypothalamic-pituitary-adrenal (HPA) axis contributes to the regulation of T cell activation in HIV. This may represent an important pathway through which psychological states and the HPA axis influence progression of HIV
Fabrication of Microfluidic Devices with Integrated Electronic Components via Dual Extrusion-Based 3D Printing
Microfluidics channels as small as 50 μm in width were produced via extrusionbased 3D printing. Multi-layered, multi-electrode devices were fabricated with inlaid conductive filament. Electrodes were used for simple electroanalysis of proteins. Prototyping of microfluidics devices via extrusion-based 3D printing may ultimately allow for an easy, cost-effective, high-throughput, high-resolution, and single-step method of rapidly prototyping electronic microfluidic devices, principally suited for use in diagnostics applications
A Study of the Growth in English Proficiency of Omaha Public High School Students Enrolled in Traditional and Non-Traditional Programs
Since the fall of 1970, an elective English program has been available for senior high students in the Omaha Public Schools. Although all senior high schools have sampled the program called Special-Interest English, only four of the eight high schools have adopted it in total. Since its inception, the program has become increasingly sophisticated developing somewhat differently in each school. Technical High School, which adopted the elective program, has now expanded it into an individualized program so unique and complex that that school will not be included in this study
Persistent LHPA Activation in German Individuals Raised in an Overprotective Parental Behavior
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.Parental upbringing may affect their offspring’s mental state across the entire lifespan. Overprotective parental child-rearing style may increase the disease burden in the offspring. Furthermore, this child-rearing style may also play a pathogenetic role by transmitting trauma- and stressor-related disorders (TSRD) across generations. Studies with animals have demonstrated that the mother’s immediate and expansive protection of the newborn decreases the limbic-hypothalamic-pituitary-adrenal (LHPA) axis activity in the offspring. However, few studies have investigated how stress impact humans raised in an overprotective manner. In a cross-sectional study with 40 healthy students recalling their overprotective upbringing, we show an increase in the dehydroepiandrostendione (DHEA) concentration and a reduction in the cortisol/DHEA-ratio in hair. Additionally, this child rearing style was associated with heightened indications of mental burden, depressiveness, and sense of coherence. Our results provide insight into the roots and consequences of psychological trauma across several generations. Further investigations focusing particularly on multigenerational transmission in extremely burdened families will augment our results
Persistent depressive symptoms, HPA-axis hyperactivity, and inflammation: the role of cognitive-affective and somatic symptoms
Hypothalamic-pituitary-adrenal (HPA)-axis hyperactivity and inflammation are thought to be prominent in the aetiology of
depression. Although meta-analyses have confirmed this relationship, there is considerable variability in the effect sizes
across studies. This could be attributed to a differential role of such biological systems in somatic versus cognitive-affective
depressive symptoms which remains largely unexplored. Furthermore, most longitudinal research to date has focused on
transient rather than persistent depressive symptoms. In the current study, we investigated the associations of hair cortisol
and plasma C-reactive protein (CRP) with the longitudinal persistence and dimensions (cognitive-affective versus somatic)
of depressive symptoms over a 14-year period using Trait‐State‐Occasion (TSO) structural equation modelling. The data
came from a large sample of older adults from the English Longitudinal Study of Ageing. Depressive symptoms were
assessed from wave 1 (2002–03) to wave 8 (2016–17). Hair cortisol (N = 4761) and plasma CRP (N = 5784) were measured
in wave 6 (2012–13). Covariates included demographic, socioeconomic, lifestyle, chronic disease, and medication data. Our
results revealed that higher cortisol and CRP levels were significantly associated with persistent depressive symptoms across
the study period. Notably, both biomarkers exhibited stronger relationships with somatic than with cognitive-affective
symptoms. The associations with somatic symptoms were also independent of relevant confounding factors. In contrast, their
associations with cognitive-affective symptoms were weak after adjustment for all covariates. These distinct associations
reveal the importance of considering symptom-specific effects in future studies on pathophysiological mechanisms.
Ultimately, this will have the potential to advance the search for biomarkers of depression and facilitate more targeted
treatments
Characterization and Fate of a Septanosyl Ferrier Cation in the Gas and Solution Phases
Ferrier reactions follow a mechanistic pathway whereby Lewis acid activation of a cyclic enol ether facilitates departure of an allylic leaving group to form a glycosyl Ferrier cation. Attack on the Ferrier cation provides a new acetal linkage concurrent with the transposition of the alkene moiety. The idiosyncratic outcomes of Ferrier reactions of seven-membered ring carbohydrate-based oxepines prompted an investigation of its corresponding septanosyl Ferrier cation. Experiments that characterized the ion, including gas-phase cryogenic IR spectroscopy matched with density functional theory-calculated spectra of candidate cation structures, as well as product analysis from solution-phase Ferrier reactions, are reported here. Results from both approaches revealed an inclination of the seven-membered ring cation to contract to five-membered ring structures. Gas-phase IR spectra matched best to calculated spectra of structures in which five-membered dioxolenium formation opened the oxepine ring. In the solution phase, an attack on the ion by water led to an acyclic enal that cyclized to a C-methylene-aldehydo arabinofuranoside species. Attack by allyl trimethylsilane, on the other hand, was diastereoselective and yielded a C-allyl septanoside
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