2,027 research outputs found
Corrigendum: Airway T cells protect against RSV infection in the absence of antibody
Correction to: Mucosal Immunology (2018) 11, 249–256; doi:10.1038/mi.2017.46; published online 24 May 201
Physical-layer Security of Uplink mmWave Transmissions in Cellular V2X Networks
In this paper, we investigate physical-layer security of the uplink millimeter wave communications for a cellular vehicle-to-everything (C-V2X) network comprised of a large number of base stations (BSs) and different categories of V2X nodes, including vehicles, pedestrians, and road side units. Considering the dynamic change and randomness of the topology of the C-V2X network, we model the roadways, the V2X nodes on each roadway, and the BSs by a Poisson line process, a 1D Poisson point process (PPP), and a 2D PPP, respectively. We propose two uplink association schemes for a typical vehicle, namely, the smallest-distance association (SDA) scheme and the largest-power association (LPA) scheme, and we establish a tractable analytical framework to comprehensively assess the security performance of the uplink transmission, by leveraging the stochastic geometry theory. Specifically, for each association scheme, we first obtain new expressions for the association probability of the typical vehicle, and then derive the overall connection outage probability and secrecy outage probability by calculating the Laplace transform of the aggregate interference power. Numerical results are presented to validate our theoretical analysis, and we also provide interesting insights into how the security performance is influenced by various system parameters, including the densities of V2X nodes and BSs. Moreover, we show that the LPA scheme outperforms the SDA scheme in terms of secrecy throughput
Phytochemical Screening and Hepatoprotective Effect of Alhagi maurorum Boiss (Leguminosae) Against Paracetamol-Induced Hepatotoxicity in Rabbits
Purpose: To evaluate the hepatoprotective activity of aqueous-ethanol (30:70 %) extract of Alhagi maurorum Boiss. (Leguminosae) whole plant against paracetamol-induced liver injury in experimental rabbits.Methods: Aqueous-ethanol extract of Alhagi maurorum at doses of 250 mg/kg and 500 mg/kg body weight, p.o., was administered for 7 days in paracetamol (2 gm/kg, s.c.) intoxicated rabbits and compared with silymarine (50 mg/kg, p.o.)-treated rabbits. Biochemical parameters, alkaline phosphatase (ALP), serum glutamic oxalacetic transaminase (SGOT), serum glutamic pyruvic transaminase (SGPT) and total bilirubin (TB) levels were recorded to investigate the degree of improvement in the conditions of the rabbits. The liver was removed, washed with normal saline and preserved in 10 % formalin and used in histopathological studies of hepatic architecture by microscopy. Phytochemical screening of the extract was also carried out.Results: The levels of biochemical parameters were increased in paracetamol intoxicated rabbits when compared with the normal group. The extract, at doses of 250 and 500 mg/kg, exhibited significant (p < 0.001) reduction in biochemical parameters (ALP, SGOT, SGPT and TB). Hepatoprotective activity was also confirmed by histopathological findings. Furthermore, the phytochemical profile of the extract revealed the presence of tannins, alkaloids, saponins and flavonoids.Conclusion: These results suggest that Alhagi maurorum extract possesses significant hepatoprotective effect against paracetamol-induced hepatotoxicity and this may be due to the presence of flavonoids and tannins.Keywords: Alhagi maurorum, Hepatoprotective, Paracetamol, Silymarin, Histopatholog
EVALUATION OF DOG SLAUGHTER AND CONSUMPTION PRACTICES RELATED TO THE CONTROL OF RABIES IN NIGERIA
ABSTRACT The trade, slaughter and consumption of dog meats are some common attitudes and practices in subSaharan West African countries. These factors may represent a source of human rabies exposures and infections in the population of these countries and may be because of these only, still rabies remain endemic disease in Nigeria. Therefore, a survey was conducted during January, 2012 to July, 2012 for finding out the rational of dog meat consumption in Niger state, Nigeria. One hundred and fifty five volunteers (146 males and 9 females), consisting of dog butchers, consumers and those who leave around the slaughter points answered a questionnaire at five dog slaughter locations across the state. Information on the dogs slaughtered was also collected. The results revealed that 125 (80.6%) of the respondents consumed dog meat (4 females and 121 males). Only 12 (9.6%) were actually engaged in dog butchering who also identified that they purchased their dogs for slaughter from households within and outside their territories, not by personal breeding. None of the butchers were vaccinated against rabies. Regarding reasons for dog meat consumption, 80 (64%) respondents indicated that the meat was delicious, 23 (18.4%) claimed medicinal purposes, and 1 (0.8%) respondent believed that its consumption protected against the witches. Overall, 471 dogs were recorded to be slaughtered for human consumption during the study period. Despite their rational, the practices of dog trade, slaughter and consumption were detrimental to dogs as well as the control of rabies, particularly when evidence indicated that up to 28% of dogs slaughtered for human consumption in Nigeria may harbor the rabies virus. KEYWORDS Dog slaughter Dog consumption Rabies Nigeri
Inflation on the Brane with Vanishing Gravity
Many existing models of brane inflation suffer from a steep irreducible
gravitational potential between the branes that causes inflation to end too
early. Inspired by the fact that point masses in 2+1 D exert no gravitational
force, we propose a novel unwarped and non-supersymmetric setup for inflation,
consisting of 3-branes in two extra dimensions compactified on a sphere. The
size of the sphere is stabilized by a combination of a bulk cosmological
constant and a magnetic flux. Computing the 4D effective potential between
probe branes in this background, we find a non-zero contribution only from
exchange of level-1 KK modes of the graviton and radion. Identifying antipodal
points on the 2-sphere projects out these modes, eliminating entirely the
troublesome gravitational contribution to the inflationary potential.Comment: 19 pages, 11 figures, JHEP forma
X-Ray Spectroscopy of Stars
(abridged) Non-degenerate stars of essentially all spectral classes are soft
X-ray sources. Low-mass stars on the cooler part of the main sequence and their
pre-main sequence predecessors define the dominant stellar population in the
galaxy by number. Their X-ray spectra are reminiscent, in the broadest sense,
of X-ray spectra from the solar corona. X-ray emission from cool stars is
indeed ascribed to magnetically trapped hot gas analogous to the solar coronal
plasma. Coronal structure, its thermal stratification and geometric extent can
be interpreted based on various spectral diagnostics. New features have been
identified in pre-main sequence stars; some of these may be related to
accretion shocks on the stellar surface, fluorescence on circumstellar disks
due to X-ray irradiation, or shock heating in stellar outflows. Massive, hot
stars clearly dominate the interaction with the galactic interstellar medium:
they are the main sources of ionizing radiation, mechanical energy and chemical
enrichment in galaxies. High-energy emission permits to probe some of the most
important processes at work in these stars, and put constraints on their most
peculiar feature: the stellar wind. Here, we review recent advances in our
understanding of cool and hot stars through the study of X-ray spectra, in
particular high-resolution spectra now available from XMM-Newton and Chandra.
We address issues related to coronal structure, flares, the composition of
coronal plasma, X-ray production in accretion streams and outflows, X-rays from
single OB-type stars, massive binaries, magnetic hot objects and evolved WR
stars.Comment: accepted for Astron. Astrophys. Rev., 98 journal pages, 30 figures
(partly multiple); some corrections made after proof stag
Fungal Adenylyl Cyclase Acts As a Signal Sensor and Integrator and Plays a Central Role in Interaction with Bacteria
10.1371/journal.ppat.1003612PLoS Pathogens910
Can Bcl-XL expression predict the radio sensitivity of Bilharzial-related squamous bladder carcinoma? a prospective comparative study
<p>Abstract</p> <p>Background</p> <p>Local pelvic recurrence after radical cystectomy for muscle invasive bilharzial related squamous cell carcinoma accounts for 75% of treatment failures even in organ confined tumors. Despite the proven value of lymphadenectomy, up to 60% of patients undergoing cystectomy do not have it. These factors are in favor of adjuvant radiotherapy reevaluation. objectives: to evaluate the effect of adjuvant radiotherapy on disease free survival in muscle invasive bilharzial related squamous cell carcinoma of the urinary bladder and to test the predictability of radio-sensitivity using the anti apoptotic protein Bcl-XL.</p> <p>Methods</p> <p>The study prospectively included 71 patients, (47 males, 24 females) with muscle invasive bilharzial related squamous cell carcinoma of the bladder (Stage pT2a-T3N0-N3M0) who underwent radical cystectomy in Assiut university hospitals between January 2005 and December 2006. Thirty eight patients received adjuvant radiotherapy to the pelvis in the dose of 50Gy/25 fractions/5 weeks (Group 1), while 33 patients did not receive adjuvant radiotherapy (group 2). Immunohistochemical characterization for bcl-xL expression was done. Follow up was done every 3 months for 12 to 36 months with a mean of 16 ± 10 months. All data were analyzed using SPSS version 16. Three years cumulative disease free survival was calculated and adjusted to Bcl-XL expression and side effects of the treatment were recorded.</p> <p>Results</p> <p>The disease free cumulative survival was 48% for group 1 and 29% for group 2 (log rank p value 0.03). The multivariate predictors of tumor recurrence were the positive Bcl-XL expression (odd ratio 41.1, 95% CI 8.4 - 102.3, p < 0.0001) and radiotherapy (odd ratio 0.19, 95% CI 0.05 - 0.78, p < 0.02). With Cox regression, the only independent multivariate predictor of radio-sensitivity was the Bcl-XL expression with odd ratio 4.6 and a p value < 0.0001. All patients tolerated the treatment with no life threatening or late complications during the period of follow up.</p> <p>Conclusions</p> <p>Adjuvant radiotherapy for muscle invasive bilharzial related squamous cell carcinoma of the urinary bladder has potential effectiveness and minor side effects. Moreover, Bcl-XL expression is a valuable tool for predicting those who might not respond to this adjuvant treatment.</p
Combined SVM-CRFs for Biological Named Entity Recognition with Maximal Bidirectional Squeezing
Biological named entity recognition, the identification of biological terms in text, is essential for biomedical information extraction. Machine learning-based approaches have been widely applied in this area. However, the recognition performance of current approaches could still be improved. Our novel approach is to combine support vector machines (SVMs) and conditional random fields (CRFs), which can complement and facilitate each other. During the hybrid process, we use SVM to separate biological terms from non-biological terms, before we use CRFs to determine the types of biological terms, which makes full use of the power of SVM as a binary-class classifier and the data-labeling capacity of CRFs. We then merge the results of SVM and CRFs. To remove any inconsistencies that might result from the merging, we develop a useful algorithm and apply two rules. To ensure biological terms with a maximum length are identified, we propose a maximal bidirectional squeezing approach that finds the longest term. We also add a positive gain to rare events to reinforce their probability and avoid bias. Our approach will also gradually extend the context so more contextual information can be included. We examined the performance of four approaches with GENIA corpus and JNLPBA04 data. The combination of SVM and CRFs improved performance. The macro-precision, macro-recall, and macro-F1 of the SVM-CRFs hybrid approach surpassed conventional SVM and CRFs. After applying the new algorithms, the macro-F1 reached 91.67% with the GENIA corpus and 84.04% with the JNLPBA04 data
Structure-based statistical analysis of transmembrane helices
Recent advances in determination of the high-resolution structure of membrane proteins now enable analysis of the main features of amino acids in transmembrane (TM) segments in comparison with amino acids in water-soluble helices. In this work, we conducted a large-scale analysis of the prevalent locations of amino acids by using a data set of 170 structures of integral membrane proteins obtained from the MPtopo database and 930 structures of water-soluble helical proteins obtained from the protein data bank. Large hydrophobic amino acids (Leu, Val, Ile, and Phe) plus Gly were clearly prevalent in TM helices whereas polar amino acids (Glu, Lys, Asp, Arg, and Gln) were less frequent in this type of helix. The distribution of amino acids along TM helices was also examined. As expected, hydrophobic and slightly polar amino acids are commonly found in the hydrophobic core of the membrane whereas aromatic (Trp and Tyr), Pro, and the hydrophilic amino acids (Asn, His, and Gln) occur more frequently in the interface regions. Charged amino acids are also statistically prevalent outside the hydrophobic core of the membrane, and whereas acidic amino acids are frequently found at both cytoplasmic and extra-cytoplasmic interfaces, basic amino acids cluster at the cytoplasmic interface. These results strongly support the experimentally demonstrated biased distribution of positively charged amino acids (that is, the so-called the positive-inside rule) with structural data
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