473 research outputs found
Nonlinear distortion of intense THz beams
Near- and far-field beam profiles were measured for THz pulses generated in LiNbO3 by optical rectification of 200 fs pulses with a tilted pulse front. The variation of the THz beam size and a dramatically increasing divergence angle with increasing pump fluence were observed in the
(horizontal) plane of the pulse front tilt. No significant variation was observed in the vertical direction.
The reason for the observed nonlinear beam distortion is the shortening of the effective interaction length for THz generation caused by the combined effect of pump spectral broadening and angular dispersion in the tilted pulse front geometry. Our results indicate that nonlinear THz beam distortion effects have to be taken into account when designing intense THz sources and related experiments
Coordinated changes in energy intake and expenditure following hypothalamic administration of neuropeptides involved in energy balance
OBJECTIVE: The hypothalamic control of energy balance is regulated by a complex network of neuropeptide-releasing neurons. Whilst the effect of these neuropeptides on individual aspects of energy homeostasis has been studied, the coordinated response of these effects has not been comprehensively investigated. We have simultaneously monitored a number of metabolic parameters following ICV administration of 1nmol and 3nmol of neuropeptides with established roles in the regulation of feeding, activity and metabolism. Ad libitum fed rats received the orexigenic neuropeptides neuropeptide Y (NPY), agouti-related protein (AgRP), melanin-concentrating hormone (MCH) or orexin-A. Overnight food deprived rats received an ICV injection of the anorectic peptides α-MSH, corticotrophin releasing factor (CRF) or neuromedin U (NMU). RESULTS: Our results reveal the temporal sequence of the effects of these neuropeptides on both energy intake and expenditure, highlighting key differences in their function as mediators of energy balance. NPY and AgRP increased feeding and decreased oxygen consumption, with the effects of AgRP being more prolonged. In contrast, orexin-A increased both feeding and oxygen consumption, consistent with an observed increase in activity. The potent anorexigenic effects of CRF were accompanied by a prolonged increase in activity whilst NMU injection resulted in significant but short-lasting inhibition of food intake, ambulatory activity and oxygen consumption. Alpha-MSH injection resulted in significant increases in both ambulatory activity and oxygen consumption, and reduced food intake following administration of 3nmol of the peptide. CONCLUSION: We have for the first time, simultaneously measured several metabolic parameters following hypothalamic administration of a number of neuropeptides within the same experimental system. This work has demonstrated the interrelated effects of these neuropeotides on activity, energy expenditure and food intake thus facilitating comparison between the different hypothalamic systems
Interactions between the melanocortin system and the hypothalamo-pituitary-thyroid axis.
The melanocortin 1 receptor is the principal mediator of the effects of agouti signaling protein on mammalian melanocytes
Lassa Fever in Post-Conflict Sierra Leone
Background: Lassa fever (LF), an often-fatal hemorrhagic disease caused by Lassa virus (LASV), is a major public health threat in West Africa. When the violent civil conflict in Sierra Leone (1991 to 2002) ended, an international consortium assisted in restoration of the LF program at Kenema Government Hospital (KGH) in an area with the world's highest incidence of the disease. Methodology/Principal Findings Clinical and laboratory records of patients presenting to the KGH Lassa Ward in the post-conflict period were organized electronically. Recombinant antigen-based LF immunoassays were used to assess LASV antigenemia and LASV-specific antibodies in patients who met criteria for suspected LF. KGH has been reestablished as a center for LF treatment and research, with over 500 suspected cases now presenting yearly. Higher case fatality rates (CFRs) in LF patients were observed compared to studies conducted prior to the civil conflict. Different criteria for defining LF stages and differences in sensitivity of assays likely account for these differences. The highest incidence of LF in Sierra Leone was observed during the dry season. LF cases were observed in ten of Sierra Leone's thirteen districts, with numerous cases from outside the traditional endemic zone. Deaths in patients presenting with LASV antigenemia were skewed towards individuals less than 29 years of age. Women self-reporting as pregnant were significantly overrepresented among LASV antigenemic patients. The CFR of ribavirin-treated patients presenting early in acute infection was lower than in untreated subjects. Conclusions/Significance: Lassa fever remains a major public health threat in Sierra Leone. Outreach activities should expand because LF may be more widespread in Sierra Leone than previously recognized. Enhanced case finding to ensure rapid diagnosis and treatment is imperative to reduce mortality. Even with ribavirin treatment, there was a high rate of fatalities underscoring the need to develop more effective and/or supplemental treatments for LF
Filovirus RefSeq Entries: Evaluation and Selection of Filovirus Type Variants, Type Sequences, and Names
Sequence determination of complete or coding-complete genomes of viruses is becoming common practice for supporting the work of epidemiologists, ecologists, virologists, and taxonomists. Sequencing duration and costs are rapidly decreasing, sequencing hardware is under modification for use by non-experts, and software is constantly being improved to simplify sequence data management and analysis. Thus, analysis of virus disease outbreaks on the molecular level is now feasible, including characterization of the evolution of individual virus populations in single patients over time. The increasing accumulation of sequencing data creates a management problem for the curators of commonly used sequence databases and an entry retrieval problem for end users. Therefore, utilizing the data to their fullest potential will require setting nomenclature and annotation standards for virus isolates and associated genomic sequences. The National Center for Biotechnology Information’s (NCBI’s) RefSeq is a non-redundant, curated database for reference (or type) nucleotide sequence records that supplies source data to numerous other databases. Building on recently proposed templates for filovirus variant naming [ ()////-], we report consensus decisions from a majority of past and currently active filovirus experts on the eight filovirus type variants and isolates to be represented in RefSeq, their final designations, and their associated sequences
Genome-wide association studies of autoimmune vitiligo identify 23 new risk loci and highlight key pathways and regulatory variants
Vitiligo is an autoimmune disease in which depigmented skin results from the destruction of melanocytes1, with epidemiological association with other autoimmune diseases2. In previous linkage and genome-wide association studies (GWAS1 and GWAS2), we identified 27 vitiligo susceptibility loci in patients of European ancestry. We carried out a third GWAS (GWAS3) in European-ancestry subjects, with augmented GWAS1 and GWAS2 controls, genome-wide imputation, and meta-analysis of all three GWAS, followed by an independent replication. The combined analyses, with 4,680 cases and 39,586 controls, identified 23 new significantly associated loci and 7 suggestive loci. Most encode immune and apoptotic regulators, with some also associated with other autoimmune diseases, as well as several melanocyte regulators. Bioinformatic analyses indicate a predominance of causal regulatory variation, some of which corresponds to expression quantitative trait loci (eQTLs) at these loci. Together, the identified genes provide a framework for the genetic architecture and pathobiology of vitiligo, highlight relationships with other autoimmune diseases and melanoma, and offer potential targets for treatment
Subclinical patterns of disordered eating behaviors in the daily life of adolescents and young adults from the general population.
BACKGROUND
Disordered eating behaviors (DEBs), a risk factor for the development of eating disorders (EDs), are prevalent in young people and different DEBs frequently co-occur. Previous studies on DEB-patterns have largely used traditional retrospective questionnaires to assess DEBs. In addition, most previous studies did not specifically exclude individuals with clinical EDs, which limits current knowledge concerning purely subclinical patterns of DEBs. In the present study, we aimed to explore phenotypes and group sizes of subclinical patterns of DEBs reported in everyday life via smartphone-based ecological momentary assessment (EMA) in adolescents and young adults from the general population without lifetime EDs. In secondary analyses, we further aimed to investigate whether DEB-patterns would be associated with additional previously identified risk factors for ED-development.
METHODS
EMA was conducted in a community sample of 14-21-year-olds from Dresden, Germany, over four days for up to eight times a day and covered engagement in four DEBs: skipping eating, restrained eating, eating large amounts of food, and loss-of-control eating. Data were analyzed from N = 966 individuals without lifetime EDs with an EMA compliance rate of at least 50% (81.9% of the total sample; average compliance: 84.6%). Latent profile analyses were performed to identify subclinical patterns of DEBs, stratified by sex. Associations between symptomatic profiles and ED-risk factors were tested via regression analyses.
RESULTS
Based on theoretical deliberations, statistical indices, interpretability, and parsimony, a three-profile solution, namely no DEBs, high-mixed DEBs, and low-mixed DEBs, was selected for both sexes. Both symptomatic profiles in both sexes were associated with more unfavorable manifestations in additional ED risk factors compared to the no DEBs profile, with the highest number of associations being observed in the female high-mixed profile.
CONCLUSIONS
The present findings suggest that problematic manifestations of DEBs in young people may occur even in the absence of an ED diagnosis and that they are associated with additional risk factors for EDs, warranting increased efforts in targeted prevention, early identification and intervention in order to counteract symptom progression
The melanocortin 1 receptor is the principal mediator of the effects of agouti signaling protein on mammalian melanocytes
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