538 research outputs found

    High-mass star formation at sub-50AU scales

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    Methods: We observed the high-mass hot core region G351.77-0.54 with ALMA and more than 16km baselines. Results: At a spatial resolution of 18/40au (depending on the distance), we identify twelve sub-structures within the inner few thousand au of the region. The brightness temperatures are high, reaching values greater 1000K, signposting high optical depth toward the peak positions. Core separations vary between sub-100au to several 100 and 1000au. The core separations and approximate masses are largely consistent with thermal Jeans fragmentation of a dense gas core. Due to the high continuum optical depth, most spectral lines are seen in absorption. However, a few exceptional emission lines are found that most likely stem from transitions with excitation conditions above1000K. Toward the main continuum source, these emission lines exhibit a velocity gradient across scales of 100-200au aligned with the molecular outflow and perpendicular to the previously inferred disk orientation. While we cannot exclude that these observational features stem from an inner hot accretion disk, the alignment with the outflow rather suggests that it stems from the inner jet and outflow region. The highest-velocity features are found toward the peak position, and no Hubble-like velocity structure can be identified. Therefore, these data are consistent with steady-state turbulent entrainment of the hot molecular gas via Kelvin-Helmholtz instabilities at the interface between the jet and the outflow. Conclusions: Resolving this high-mass star-forming region at sub-50au scales indicates that the hierarchical fragmentation process in the framework of thermal Jeans fragmentation can continue down to the smallest accessible spatial scales. Velocity gradients on these small scales have to be treated cautiously and do not necessarily stem from disks, but may be better explained with outflow emission

    Patient advocacy: barriers and facilitators

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    BACKGROUND: During the two recent decades, advocacy has been a topic of much debate in the nursing profession. Although advocacy has embraced a crucial role for nurses, its extent is often limited in practice. While a variety of studies have been generated all over the world, barriers and facilitators in the patient advocacy have not been completely identified. This article presents the findings of a study exploring the barriers and facilitators influencing the role of advocacy among Iranian nurses. METHOD: This study was conducted by grounded theory method. Participants were 24 Iranian registered nurses working in a large university hospital in Tehran, Iran. Semi-structured interviews were used for data collection. All interviews were transcribed verbatim and simultaneously Constant comparative analysis was used according to the Strauss and Corbin method. RESULTS: Through data analysis, several main themes emerged to describe the factors that hindered or facilitated patient advocacy. Nurses in this study identified powerlessness, lack of support, law, code of ethics and motivation, limited communication, physicians leading, risk of advocacy, royalty to peers, and insufficient time to interact with patients and families as barriers to advocacy. As for factors that facilitated nurses to act as a patient advocate, it was found that the nature of nurse-patient relationship, recognizing patients' needs, nurses' responsibility, physician as a colleague, and nurses' knowledge and skills could be influential in adopting the advocacy role. CONCLUSION: Participants believed that in this context taking an advocacy role is difficult for nurses due to the barriers mentioned. Therefore, they make decisions and act as a patient's advocate in any situation concerning patient needs and status of barriers and facilitators. In most cases, they can not act at an optimal level; instead they accept only what they can do, which we called 'limited advocacy' in this study. It is concluded that advocacy is contextually complex, and is a controversial and risky component of the nursing practice. Further research is needed to determine the possibility of a correlation between identified barriers/ facilitators and the use of advocacy

    Informant-reported cognitive symptoms that predict amnestic mild cognitive impairment

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    <p>Abstract</p> <p>Background</p> <p>Differentiating amnestic mild cognitive impairment (aMCI) from normal cognition is difficult in clinical settings. Self-reported and informant-reported memory complaints occur often in both clinical groups, which then necessitates the use of a comprehensive neuropsychological examination to make a differential diagnosis. However, the ability to identify cognitive symptoms that are predictive of aMCI through informant-based information may provide some clinical utility in accurately identifying individuals who are at risk for developing Alzheimer's disease (AD).</p> <p>Methods</p> <p>The current study utilized a case-control design using data from an ongoing validation study of the Alzheimer's Questionnaire (AQ), an informant-based dementia assessment. Data from 51 cognitively normal (CN) individuals participating in a brain donation program and 47 aMCI individuals seen in a neurology practice at the same institute were analyzed to determine which AQ items differentiated aMCI from CN individuals.</p> <p>Results</p> <p>Forward stepwise multiple logistic regression analysis which controlled for age and education showed that 4 AQ items were strong indicators of aMCI which included: repetition of statements and/or questions [OR 13.20 (3.02, 57.66)]; trouble knowing the day, date, month, year, and time [OR 17.97 (2.63, 122.77)]; difficulty managing finances [OR 11.60 (2.10, 63.99)]; and decreased sense of direction [OR 5.84 (1.09, 31.30)].</p> <p>Conclusions</p> <p>Overall, these data indicate that certain informant-reported cognitive symptoms may help clinicians differentiate individuals with aMCI from those with normal cognition. Items pertaining to repetition of statements, orientation, ability to manage finances, and visuospatial disorientation had high discriminatory power.</p

    Past Achievements and Future Challenges in 3D Photonic Metamaterials

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    Photonic metamaterials are man-made structures composed of tailored micro- or nanostructured metallo-dielectric sub-wavelength building blocks that are densely packed into an effective material. This deceptively simple, yet powerful, truly revolutionary concept allows for achieving novel, unusual, and sometimes even unheard-of optical properties, such as magnetism at optical frequencies, negative refractive indices, large positive refractive indices, zero reflection via impedance matching, perfect absorption, giant circular dichroism, or enhanced nonlinear optical properties. Possible applications of metamaterials comprise ultrahigh-resolution imaging systems, compact polarization optics, and cloaking devices. This review describes the experimental progress recently made fabricating three-dimensional metamaterial structures and discusses some remaining future challenges

    WR279,396, a Third Generation Aminoglycoside Ointment for the Treatment of Leishmania major Cutaneous Leishmaniasis: A Phase 2, Randomized, Double Blind, Placebo Controlled Study

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    Cutaneous leishmaniasis is due to a small parasite (Leishmania) that creates disfiguring sores, and affects more than one million persons (mainly children) each year. Treating lesions with a cream—instead of with injections as currently done—would greatly improve the well-being of affected patients. No cream formulation that would be efficient and would not create important skin irritation has been identified yet. Here, we tested a new cream formulation (WR279,396) containing paromomycin and gentamicin, two members of a well-known family of antibacterial antibiotics (aminoglycosides). Injectable paromomycin is efficient in other forms of the disease (visceral leishmaniasis). This was a carefully monitored study (phase 2) involving mainly children in Tunisia and France. The cream was applied twice a day for 20 days. The proportion of patients treated with the paromomycin-containing cream (active formulation) that cured (94%) was higher than that observed (71%) in patients treated with a cream that did not contain the active product (placebo formulation). Local irritation affected less than one-third of the patients and was usually mild. This new cream formulation was safe and effective in treating cutaneous leishmaniasis, thereby providing a new, simple, easily applicable, and inexpensive treatment for this neglected disease

    Rapid production of human liver scaffolds for functional tissue engineering by high shear stress oscillation-decellularization

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    The development of human liver scaffolds retaining their 3-dimensional structure and extra-cellular matrix (ECM) composition is essential for the advancement of liver tissue engineering. We report the design and validation of a new methodology for the rapid and accurate production of human acellular liver tissue cubes (ALTCs) using normal liver tissue unsuitable for transplantation. The application of high shear stress is a key methodological determinant accelerating the process of tissue decellularization while maintaining ECM protein composition, 3D-architecture and physico-chemical properties of the native tissue. ALTCs were engineered with human parenchymal and non-parenchymal liver cell lines (HepG2 and LX2 cells, respectively), human umbilical vein endothelial cells (HUVEC), as well as primary human hepatocytes and hepatic stellate cells. Both parenchymal and non-parenchymal liver cells grown in ALTCs exhibited markedly different gene expression when compared to standard 2D cell cultures. Remarkably, HUVEC cells naturally migrated in the ECM scaffold and spontaneously repopulated the lining of decellularized vessels. The metabolic function and protein synthesis of engineered liver scaffolds with human primary hepatocytes reseeded under dynamic conditions were maintained. These results provide a solid basis for the establishment of effective protocols aimed at recreating human liver tissue in vitro

    Rare variation at the TNFAIP3 locus and susceptibility to rheumatoid arthritis

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    Genome-wide association studies (GWAS) conducted using commercial single nucleotide polymorphisms (SNP) arrays have proven to be a powerful tool for the detection of common disease susceptibility variants. However, their utility for the detection of lower frequency variants is yet to be practically investigated. Here we describe the application of a rare variant collapsing method to a large genome-wide SNP dataset, the Wellcome Trust Case Control Consortium rheumatoid arthritis (RA) GWAS. We partitioned the data into gene-centric bins and collapsed genotypes of low frequency variants (defined here as MAF ≤0.05) into a single count coupled with univariate analysis. We then prioritised gene regions for further investigation in an independent cohort of 3,355 cases and 2,427 controls based on rare variant signal p value and prior evidence to support involvement in RA. A total of 14,536 gene bins were investigated in the primary analysis and signals mapping to the TNFAIP3 and chr17q24 loci were selected for further investigation. We detected replicating association to low frequency variants in the TNFAIP3 gene (combined p = 6.6 × 10−6). Even though rare variants are not well-represented and can be difficult to genotype in GWAS, our study supports the application of low frequency variant collapsing methods to genome-wide SNP datasets as a means of exploiting data that are routinely ignored

    Changes in Plasma Membrane Surface Potential of PC12 Cells as Measured by Kelvin Probe Force Microscopy

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    The plasma membrane of a cell not only works as a physical barrier but also mediates the signal relay between the extracellular milieu and the cell interior. Various stimulants may cause the redistribution of molecules, like lipids, proteins, and polysaccharides, on the plasma membrane and change the surface potential (Φs). In this study, the Φss of PC12 cell plasma membranes were measured by atomic force microscopy in Kelvin probe mode (KPFM). The skewness values of the Φss distribution histogram were found to be mostly negative, and the incorporation of negatively charged phosphatidylserine shifted the average skewness values to positive. After being treated with H2O2, dopamine, or Zn2+, phosphatidylserine was found to be translocated to the membrane outer leaflet and the averaged skewness values were changed to positive values. These results demonstrated that KPFM can be used to monitor cell physiology status in response to various stimulants with high spatial resolution

    Baclofen for maintenance treatment of opioid dependence: A randomized double-blind placebo-controlled clinical trial [ISRCTN32121581]

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    BACKGROUND: Results of preclinical studies suggest that the GABA(B )receptor agonist baclofen may be useful in treatment of opioid dependence. This study was aimed at assessing the possible efficacy of baclofen for maintenance treatment of opioid dependence. METHODS: A total of 40 opioid-dependent patients were detoxified and randomly assigned to receive baclofen (60 mg/day) or placebo in a 12-week, double blind, parallel-group trial. Primary outcome measure was retention in treatment. Secondary outcome measures included opioids and alcohol use according to urinalysis and self-report ratings, intensity of opioid craving assessed with a visual analogue scale, opioid withdrawal symptoms as measured by the Short Opiate Withdrawal Scale and depression scores on the Hamilton inventory. RESULTS: Treatment retention was significantly higher in the baclofen group. Baclofen also showed a significant superiority over placebo in terms of opiate withdrawal syndrome and depressive symptoms. Non-significant, but generally favorable responses were seen in the baclofen group with other outcome measures including intensity of opioid craving and self-reported opioid and alcohol use. However, no significant difference was seen in the rates of opioid-positive urine tests. Additionally, the drug side effects of the two groups were not significantly different. CONCLUSION: The results support further study of baclofen in the maintenance treatment of opioid dependence
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