971 research outputs found
Estimation of ungauged Bahr el Jebel flows based on upstream water levels and large scale spatial rainfall data
The study derives Bahr el Jebel flow data at Mongalla, combining upstream flow from Lake Albert and torrential runoff derived from the Collaborative Historical African Rainfall Model (CHARM) rainfall data in the catchment between Lake Albert and Mongalla using GIS techniques. The results provide an updated rating curve for Lake Albert outflows and currently unavailable flow data at Mongalla, the entry to the Sudd swamp, with a high level of confidence for the period after 1983; data which are essential for detailed hydrological assessments of the swamp system with its significant importance for the economies and lives of people in the area
A Bast-like valve in the pigeon?
The first description of the presence of a utriculo-endolymphatic valve in human fetuses was given by Bast in 1928. Since then this valve-like structure is called Bastâs valve. Its exact function has not yet been established. The general opinion is that it has a protective function by having the possibility to separate the superior endolymphatic compartments of the labyrinth from the inferior compartment. Phylogenetically seen birds are the first vertebrates with a cochlear duct and a distinct inferior and superior part of the labyrinth. A structure in the pigeon inner ear, resembling Bastâs valve in mammals, is described
Saccade dysmetria indicates attenuated visual exploration in autism spectrum disorder
Background:
Visual exploration in autism spectrum disorder (ASD) is characterized by attenuated social attention. The underlying oculomotor function during visual exploration is understudied, whereas oculomotor function during restricted viewing suggested saccade dysmetria in ASD by altered pontocerebellar motor modulation.
Methods:
Oculomotor function was recorded using remote eye tracking in 142 ASD participants and 142 matched neurotypical controls during free viewing of naturalistic videos with and without human content. The sample was heterogenous concerning age (6â30 years), cognitive ability (60â140 IQ), and male/female ratio (3:1). Oculomotor function was defined as saccade, fixation, and pupilâdilation features that were compared between groups in linear mixed models. Oculomotor function was investigated as ASD classifier and features were correlated with clinical measures.
Results:
We observed decreased saccade duration (âM = â0.50, CI [â0.21, â0.78]) and amplitude (âM = â0.42, CI [â0.12, â0.72]), which was independent of human video content. We observed null findings concerning fixation and pupilâdilation features (POWER = .81). Oculomotor function is a valid ASD classifier comparable to social attention concerning discriminative power. Within ASD, saccade features correlated with measures of restricted and repetitive behavior.
Conclusions:
We conclude saccade dysmetria as ASD oculomotor phenotype relevant to visual exploration. Decreased saccade amplitude and duration indicate spatially clustered fixations that attenuate visual exploration and emphasize endogenous over exogenous attention. We propose altered pontocerebellar motor modulation as underlying mechanism that contributes to atypical (oculoâ)motor coordination and attention function in ASD
The challenges of developing rainfall intensity-duration-frequency curves and national flood hazard maps for the Caribbean
In many Caribbean countries a lack of established good practice methods means that engineers and planners are often unable to plan for and mitigate floods effectively. In most Caribbean states rainfall intensity â duration â frequency (IDF) curves are not readily available. This is a result of the limited quantity of short duration rainfall data available and also because the few IDF curves that have been developed in the region are generally not in the public domain. The lack of readily available IDF curves in the region often results in engineers responsible for the design of key infrastructure inappropriately âtransferringâ IDF curves developed for islands, where rainfall is less intense, for use in their designs. There are no countries in the Caribbean with nationally consistent flood hazard maps. This often leaves spatial and emergency planners with insufficient information to make important strategic decisions. This paper details the challenges that were faced in producing rainfall IDF curves for return periods up to 1 in 50 years and nationally consistent extreme fluvial flood extent maps with limited data for selected countries within the Caribbean. Recommendations are made for the future development of rainfall IDF curves and national flood maps in the region both in terms of data and organisational requirements
Former of Turn Trajectory of Sliding Valve Shaft of Gas Line
Former of turn trajectory of sliding valve shaft of gas line, that allows to provide desired motion trajectory of sliding valve and its full closing, is considered in that paper. Imitation model of that former, research results, which allow to detect influence of gain factor and time constant of position controller on value of speed error, that has impact on delay of output coordinate from setting, and that results to delay of sliding valve motion process to setting position point, are shown
Histamine as a marker for hydroxyl radicals
During inflammation an influx of neutrophils and release of mediators from mast cells (such as histamine) take place. The stimulated neutrophils can produce reactive oxygen species (ROS). One of these ROS is the highly reactive hydroxyl radical (OH.). It would be interesting to be able to quantify the extent of ROS formation. We investigated if histamine which is present at the inflammation site can serve as an endogenous marker for the formation of OH.. We found that histamine after incubation with OH. gave two distinct products in our HPLC system. One of the products gave the same characteristics as the synthesized 2-imidazolone derivative of histamine. This suggests that this derivative will be formed when histamine is incubated with OH.
First annotated draft genomes of nonmarine ostracods (Ostracoda, Crustacea) with different reproductive modes.
Ostracods are one of the oldest crustacean groups with an excellent fossil record and high importance for phylogenetic analyses but genome resources for this class are still lacking. We have successfully assembled and annotated the first reference genomes for three species of nonmarine ostracods; two with obligate sexual reproduction (Cyprideis torosa and Notodromas monacha) and the putative ancient asexual Darwinula stevensoni. This kind of genomic research has so far been impeded by the small size of most ostracods and the absence of genetic resources such as linkage maps or BAC libraries that were available for other crustaceans. For genome assembly, we used an Illumina-based sequencing technology, resulting in assemblies of similar sizes for the three species (335-382 Mb) and with scaffold numbers and their N50 (19-56 kb) in the same orders of magnitude. Gene annotations were guided by transcriptome data from each species. The three assemblies are relatively complete with BUSCO scores of 92-96. The number of predicted genes (13,771-17,776) is in the same range as Branchiopoda genomes but lower than in most malacostracan genomes. These three reference genomes from nonmarine ostracods provide the urgently needed basis to further develop ostracods as models for evolutionary and ecological research
HER2 testing in breast cancer: Opportunities and challenges
Human epidermal growth factor receptor 2 (HER2) is overexpressed in 15-25% of breast cancers, usually as a result of HER2 gene amplification. Positive HER2 status is considered to be an adverse prognostic factor. Recognition of the role of HER2 in breast cancer growth has led to the development of anti-HER2 directed therapy, with the humanized monoclonal antibody trastuzumab (Herceptin (R)) having been approved for the therapy of HER2-positive metastatic breast cancer. Clinical studies have further suggested that HER2 status can provide important information regarding success or failure of certain hormonal therapies or chemotherapies. As a result of these developments, there has been increasing demand to perform HER2 testing on current and archived breast cancer specimens. This article reviews the molecular background of HER2 function, activation and inhibition as well as current opinions concerning its role in chemosensitivity and interaction with estrogen receptor biology. The different tissue-based assays used to detect HER2 amplification and overexpression are discussed with respect to their advantages and disadvantages, when to test (at initial diagnosis or pre-treatment), where to test (locally or centralized) and the need for quality assurance to ensure accurate and valid testing results
Histone deacetylases as new therapy targets for platinum-resistant epithelial ovarian cancer
Introduction: In developed countries, ovarian cancer is the fourth most common cancer in women. Due to the nonspecific symptomatology associated with the disease many patients with ovarian cancer are diagnosed late, which leads to significantly poorer prognosis. Apart from surgery and radiotherapy, a substantial number of ovarian cancer patients will undergo chemotherapy and platinum based agents are the mainstream first-line therapy for this disease. Despite the initial efficacy of these therapies, many women relapse; therefore, strategies for second-line therapies are required. Regulation of DNA transcription is crucial for tumour progression, metastasis and chemoresistance which offers potential for novel drug targets. Methods: We have reviewed the existing literature on the role of histone deacetylases, nuclear enzymes regulating gene transcription. Results and conclusion: Analysis of available data suggests that a signifant proportion of drug resistance stems from abberant gene expression, therefore HDAC inhibitors are amongst the most promising therapeutic targets for cancer treatment. Together with genetic testing, they may have a potential to serve as base for patient-adapted therapies
Validation of the SCID-hu Thy/Liv mouse model with four classes of licensed antiretrovirals.
BackgroundThe SCID-hu Thy/Liv mouse model of HIV-1 infection is a useful platform for the preclinical evaluation of antiviral efficacy in vivo. We performed this study to validate the model with representatives of all four classes of licensed antiretrovirals.Methodology/principal findingsEndpoint analyses for quantification of Thy/Liv implant viral load included ELISA for cell-associated p24, branched DNA assay for HIV-1 RNA, and detection of infected thymocytes by intracellular staining for Gag-p24. Antiviral protection from HIV-1-mediated thymocyte depletion was assessed by multicolor flow cytometric analysis of thymocyte subpopulations based on surface expression of CD3, CD4, and CD8. These mice can be productively infected with molecular clones of HIV-1 (e.g., the X4 clone NL4-3) as well as with primary R5 and R5X4 isolates. To determine whether results in this model are concordant with those found in humans, we performed direct comparisons of two drugs in the same class, each of which has known potency and dosing levels in humans. Here we show that second-generation antiretrovirals were, as expected, more potent than their first-generation predecessors: emtricitabine was more potent than lamivudine, efavirenz was more potent than nevirapine, and atazanavir was more potent than indinavir. After interspecies pharmacodynamic scaling, the dose ranges found to inhibit viral replication in the SCID-hu Thy/Liv mouse were similar to those used in humans. Moreover, HIV-1 replication in these mice was genetically stable; treatment of the mice with lamivudine did not result in the M184V substitution in reverse transcriptase, and the multidrug-resistant NY index case HIV-1 retained its drug-resistance substitutions.ConclusionGiven the fidelity of such comparisons, we conclude that this highly reproducible mouse model is likely to predict clinical antiviral efficacy in humans
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