1,937 research outputs found
The influence of collective neutrino oscillations on a supernova r-process
Recently, it has been demonstrated that neutrinos in a supernova oscillate
collectively. This process occurs much deeper than the conventional
matter-induced MSW effect and hence may have an impact on nucleosynthesis. In
this paper we explore the effects of collective neutrino oscillations on the
r-process, using representative late-time neutrino spectra and outflow models.
We find that accurate modeling of the collective oscillations is essential for
this analysis. As an illustration, the often-used "single-angle" approximation
makes grossly inaccurate predictions for the yields in our setup. With the
proper multiangle treatment, the effect of the oscillations is found to be less
dramatic, but still significant. Since the oscillation patterns are sensitive
to the details of the emitted fluxes and the sign of the neutrino mass
hierarchy, so are the r-process yields. The magnitude of the effect also
depends sensitively on the astrophysical conditions - in particular on the
interplay between the time when nuclei begin to exist in significant numbers
and the time when the collective oscillation begins. A more definitive
understanding of the astrophysical conditions, and accurate modeling of the
collective oscillations for those conditions, is necessary.Comment: 27 pages, 10 figure
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Hematopoietic Cell Transplantation in Patients With Primary Immune Regulatory Disorders (PIRD): A Primary Immune Deficiency Treatment Consortium (PIDTC) Survey.
Primary Immune Regulatory Disorders (PIRD) are an expanding group of diseases caused by gene defects in several different immune pathways, such as regulatory T cell function. Patients with PIRD develop clinical manifestations associated with diminished and exaggerated immune responses. Management of these patients is complicated; oftentimes immunosuppressive therapies are insufficient, and patients may require hematopoietic cell transplant (HCT) for treatment. Analysis of HCT data in PIRD patients have previously focused on a single gene defect. This study surveyed transplanted patients with a phenotypic clinical picture consistent with PIRD treated in 33 Primary Immune Deficiency Treatment Consortium centers and European centers. Our data showed that PIRD patients often had immunodeficient and autoimmune features affecting multiple organ systems. Transplantation resulted in resolution of disease manifestations in more than half of the patients with an overall 5-years survival of 67%. This study, the first to encompass disorders across the PIRD spectrum, highlights the need for further research in PIRD management
Direct Imaging of Charge Redistribution due to Bonding at Atomic Resolution via Electron Ptychography
Phase imaging in electron microscopy is sensitive to the local potential
including charge redistribution from bonding. We demonstrate that electron
ptychography provides the necessary sensitivity to detect this subtle effect by
directly imaging the charge redistribution in single layer boron nitride.
Residual aberrations can be measured and corrected post-collection, and
simultaneous atomic number contrast imaging provides unambiguous sub-lattice
identification. Density functional theory calculations confirm the detection of
charge redistribution
Modulation of the immune response to Mycobacterium tuberculosis during malaria/M. tuberculosis co-infection
Tuberculosis (TB) causes significant morbidity and mortality on a global scale. The African region has 24% of the world's TB cases. TB overlaps with other infectious diseases such as malaria and HIV, which are also highly prevalent in the African region. TB is a leading cause of death among HIV-positive patients and co-infection with HIV and TB has been described as a syndemic. In view of the overlapping epidemiology of these diseases, it is important to understand the dynamics of the immune response to TB in the context of co-infection. We investigated the cytokine response to purified protein derivative (PPD) in peripheral blood mononuclear cells from TB patients co-infected with HIV or malaria and compared it to that of malaria- and HIV-free TB patients. A total of 231 subjects were recruited for this study and classified into six groups; untreated TB-positive, TB positive subjects on TB drugs, TB- and HIV-positive, TB- and malaria-positive, latent TB and apparently healthy control subjects. Our results demonstrate maintenance of interferon (IFN)-γ production in HIV and malaria co-infected TB patients in spite of lower CD4 counts in the HIV-infected cohort. Malaria co-infection caused an increase in the production of the T helper type 2 (Th2)-associated cytokine interleukin (IL)-4 and the anti-inflammatory cytokine IL-10 in PPD-stimulated cultures. These results suggest that malaria co-infection diverts immune response against M. tuberculosis towards a Th-2/anti-inflammatory response which might have important consequences for disease progression
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An aphasia research agenda - a consensus statement from the collaboration of aphasia trialists.
Coordination of international aphasia research would minimise duplication of effort, support synergistic international activities across languages and multidisciplinary perspectives, and promote high-quality conduct and reporting of aphasia research, thereby increasing the relevance, transparency, and implementation of findings. The Collaboration of Aphasia Trialists (CATs) sought to develop an aphasia research agenda to direct future research activities, based on priorities shared by people with aphasia, family members, and healthcare professionals. Our established international research network spanning 33 countries contributed to this activity. Research literature reporting the priorities of stakeholders was reviewed and synthesised (phase 1). Representatives from Working Groups on Aphasia Assessment & Outcomes, Prognosis & Predictors of Recovery, Effectiveness of Interventions, and Societal Impact & Reintegration participated in a two-day research agenda setting meeting. The CATs expert panel refined research objectives and identified constituent components of research and methodological developments required to address these research components. The objectives and research components were grouped into overarching themes (phase 2). The resultant list was then circulated to more than 180 CATs members for review, revision, and approval. Consensus on the final aphasia research agenda and road-map was reached by CATs executive committee (phase 3). The expert panel identified five overarching research themes: (i) evidence-based interventions for people with aphasia, (ii) effective interventions to support those communicating with people with aphasia, (iii) cross-linguistic assessment and core outcomes for aphasia research, (iv) predictors of language recovery, and (v) clinical implementation of research findings. Within these broad themes, 30 research objectives and 91 individual aphasia research components were identified and sequentially ordered. This agenda builds on research priorities identified by people with aphasia and their families, and includes priorities of healthcare professionals and researchers, and will support the rehabilitation and recovery of people with aphasia. Our internationally relevant research agenda promotes rigour in methodology, considers international applicability, synergistic activities, and sharing of resources and expertise
Distinguishing Asthma Phenotypes Using Machine Learning Approaches.
Asthma is not a single disease, but an umbrella term for a number of distinct diseases, each of which are caused by a distinct underlying pathophysiological mechanism. These discrete disease entities are often labelled as asthma endotypes. The discovery of different asthma subtypes has moved from subjective approaches in which putative phenotypes are assigned by experts to data-driven ones which incorporate machine learning. This review focuses on the methodological developments of one such machine learning technique-latent class analysis-and how it has contributed to distinguishing asthma and wheezing subtypes in childhood. It also gives a clinical perspective, presenting the findings of studies from the past 5 years that used this approach. The identification of true asthma endotypes may be a crucial step towards understanding their distinct pathophysiological mechanisms, which could ultimately lead to more precise prevention strategies, identification of novel therapeutic targets and the development of effective personalized therapies
DNA Vaccine-Generated Duck Polyclonal Antibodies as a Postexposure Prophylactic to Prevent Hantavirus Pulmonary Syndrome (HPS)
Andes virus (ANDV) is the predominant cause of hantavirus pulmonary syndrome (HPS) in South America and the only hantavirus known to be transmitted person-to-person. There are no vaccines, prophylactics, or therapeutics to prevent or treat this highly pathogenic disease (case-fatality 35–40%). Infection of Syrian hamsters with ANDV results in a disease that closely mimics human HPS in incubation time, symptoms of respiratory distress, and disease pathology. Here, we evaluated the feasibility of two postexposure prophylaxis strategies in the ANDV/hamster lethal disease model. First, we evaluated a natural product, human polyclonal antibody, obtained as fresh frozen plasma (FFP) from a HPS survivor. Second, we used DNA vaccine technology to manufacture a polyclonal immunoglobulin-based product that could be purified from the eggs of vaccinated ducks (Anas platyrhynchos). The natural “despeciation" of the duck IgY (i.e., Fc removed) results in an immunoglobulin predicted to be minimally reactogenic in humans. Administration of ≥5,000 neutralizing antibody units (NAU)/kg of FFP-protected hamsters from lethal disease when given up to 8 days after intranasal ANDV challenge. IgY/IgYΔFc antibodies purified from the eggs of DNA-vaccinated ducks effectively neutralized ANDV in vitro as measured by plaque reduction neutralization tests (PRNT). Administration of 12,000 NAU/kg of duck egg-derived IgY/IgYΔFc protected hamsters when administered up to 8 days after intranasal challenge and 5 days after intramuscular challenge. These experiments demonstrate that convalescent FFP shows promise as a postexposure HPS prophylactic. Moreover, these data demonstrate the feasibility of using DNA vaccine technology coupled with the duck/egg system to manufacture a product that could supplement or replace FFP. The DNA vaccine-duck/egg system can be scaled as needed and obviates the necessity of using limited blood products obtained from a small number of HPS survivors. This is the first report demonstrating the in vivo efficacy of any antiviral product produced using DNA vaccine-duck/egg system
Citrulline malate supplementation does not improve German Volume Training performance or reduce muscle soreness in moderately trained males and females
Background
Use of supplements to aid performance is common practice amongst recreationally active individuals, including those without a sufficient evidence base. This investigation sought to assess whether acute supplementation with 8 g of citrulline malate (CM) (1.11: 1 ratio) would improve anaerobic performance.
Methods
A randomised double blind placebo control trial was employed, using a counterbalanced design. We recruited recreationally active men and women to take part in an isokinetic chair protocol, based on German Volume Training (GVT) whereby participants attempted to perform 10 sets of 10 repetitions against a force representing 70% of their peak concentric force.
Results
The number of repetitions achieved over the course of the GVT was 94.0 ± 7.9 and 90.9 ± 13.9 for placebo and CM respectively. There was no significant difference between the placebo and CM treatment for number of repetitions (P = 0.33), isometric (P = 0.60), concentric (P = 0.38), or eccentric (P = 0.65) peak force following the GVT. Total muscle soreness was significantly higher in the CM compared to the placebo treatment following the GVT protocol over 72 h (P = 0.01); although this was not accompanied by a greater workload/number of repetitions in the CM group.
Conclusions
We conclude that an acute dose of CM does not significantly affect anaerobic performance using an isokinetic chair in recreational active participants. Practical implications include precaution in recommending CM supplementation. Coaches and athletes should be aware of the disparity between the chemical analyses of the products reviewed in the present investigation versus the manufacturers’ claims
A Fiber-Optic Fluorescence Microscope Using a Consumer-Grade Digital Camera for In Vivo Cellular Imaging
BACKGROUND: Early detection is an essential component of cancer management. Unfortunately, visual examination can often be unreliable, and many settings lack the financial capital and infrastructure to operate PET, CT, and MRI systems. Moreover, the infrastructure and expense associated with surgical biopsy and microscopy are a challenge to establishing cancer screening/early detection programs in low-resource settings. Improvements in performance and declining costs have led to the availability of optoelectronic components, which can be used to develop low-cost diagnostic imaging devices for use at the point-of-care. Here, we demonstrate a fiber-optic fluorescence microscope using a consumer-grade camera for in vivo cellular imaging. METHODS: The fiber-optic fluorescence microscope includes an LED light, an objective lens, a fiber-optic bundle, and a consumer-grade digital camera. The system was used to image an oral cancer cell line labeled with 0.01% proflavine. A human tissue specimen was imaged following surgical resection, enabling dysplastic and cancerous regions to be evaluated. The oral mucosa of a healthy human subject was imaged in vivo, following topical application of 0.01% proflavine. FINDINGS: The fiber-optic microscope resolved individual nuclei in all specimens and tissues imaged. This capability allowed qualitative and quantitative differences between normal and precancerous or cancerous tissues to be identified. The optical efficiency of the system permitted imaging of the human oral mucosa in real time. CONCLUSION: Our results indicate this device as a useful tool to assist in the identification of early neoplastic changes in epithelial tissues. This portable, inexpensive unit may be particularly appropriate for use at the point-of-care in low-resource settings
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