A Note on the Density Wave Model of the Galaxy

In this paper the general gas dynamical equations have been solved in the wave form and the general dispersion relation has been deduced. This dispersion relation has been used with simplifying assumptions plausible for special regions of the Galaxy, and results obtained have been shown to be able to interpret some observed dynamical behaviours as well as the distributional property of the gas in those special regions. For example, the analysis has yielded the interpretation of (a) the absence of any wave-pattern in the central region of the Galaxy, (b) the largescale deviation of the gas from the galactic plane in the outer regions of the Galaxy and (c) probably, the large-scale outflow of gas in the central region, as well as the large outward motion of the 3kpc arm. The analysis further indicates that in the solar neighbourhood the rotation curve of the Galaxy may possess a local maximum

Prediction of multiple infections after severe burn trauma: a prospective cohort study.

OBJECTIVE: To develop predictive models for early triage of burn patients based on hypersusceptibility to repeated infections. BACKGROUND: Infection remains a major cause of mortality and morbidity after severe trauma, demanding new strategies to combat infections. Models for infection prediction are lacking. METHODS: Secondary analysis of 459 burn patients (≥16 years old) with 20% or more total body surface area burns recruited from 6 US burn centers. We compared blood transcriptomes with a 180-hour cutoff on the injury-to-transcriptome interval of 47 patients (≤1 infection episode) to those of 66 hypersusceptible patients [multiple (≥2) infection episodes (MIE)]. We used LASSO regression to select biomarkers and multivariate logistic regression to built models, accuracy of which were assessed by area under receiver operating characteristic curve (AUROC) and cross-validation. RESULTS: Three predictive models were developed using covariates of (1) clinical characteristics; (2) expression profiles of 14 genomic probes; (3) combining (1) and (2). The genomic and clinical models were highly predictive of MIE status [AUROCGenomic = 0.946 (95% CI: 0.906-0.986); AUROCClinical = 0.864 (CI: 0.794-0.933); AUROCGenomic/AUROCClinical P = 0.044]. Combined model has an increased AUROCCombined of 0.967 (CI: 0.940-0.993) compared with the individual models (AUROCCombined/AUROCClinical P = 0.0069). Hypersusceptible patients show early alterations in immune-related signaling pathways, epigenetic modulation, and chromatin remodeling. CONCLUSIONS: Early triage of burn patients more susceptible to infections can be made using clinical characteristics and/or genomic signatures. Genomic signature suggests new insights into the pathophysiology of hypersusceptibility to infection may lead to novel potential therapeutic or prophylactic targets

Limiting damage during infection:lessons from infection tolerance for novel therapeutics

The distinction between pathogen elimination and damage limitation during infection is beginning to change perspectives on infectious disease control, and has recently led to the development of novel therapies that focus on reducing the illness caused by pathogens ("damage limitation") rather than reducing pathogen burdens directly ("pathogen elimination"). While beneficial at the individual host level, the population consequences of these interventions remain unclear. To address this issue, we present a simple conceptual framework for damage limitation during infection that distinguishes between therapies that are either host-centric (pro-tolerance) or pathogen-centric (anti-virulence). We then draw on recent developments from the evolutionary ecology of disease tolerance to highlight some potential epidemiological and evolutionary responses of pathogens to medical interventions that target the symptoms of infection. Just as pathogens are known to evolve in response to antimicrobial and vaccination therapies, we caution that claims of "evolution-proof" anti-virulence interventions may be premature, and further, that in infections where virulence and transmission are linked, reducing illness without reducing pathogen burden could have non-trivial epidemiological and evolutionary consequences that require careful examination

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Not AvailableThe objective of this study was to develop a simple and quick DNA extraction procedure for rapid diagnosis of sex of chicken and its embryos using multiplex polymerase chain reaction (PCR). Using alkaline method of DNA extraction from whole blood and feather bulb of adults, and tissue samples from embryos, the present study demonstrated that identification of sex by multiplex PCR protocol is simplest, safer, faster and inexpensive. Multiplex PCR was used to amplify W chromosome specific 481-bp fragment in female and 256bp fragment of 18S ribosomal gene in both male and female chicken. DNA samples were prepared by conventional phenol-chloroform-iso-amyl alcohol (PCI) method, modified PCI method, wizard genomic DNA purification kit and a simple alkaline method from blood samples and feather bulbs of adults and tissue samples of embryos. The protocol successfully identified sex of embryos and White Leghorn (Exotic), indigenous and Vanaraja (Hybrid of exotic and indigenous) varieties of chicken. Sequence comparison of W chromosome specific PCR products amplified from these three varieties showed no difference among them.SER

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Not AvailableA simple and rapid multiplex polymerase chain reaction (PCR) was developed for quick diagnosis of sex of duck and duck embryos. W chromosome specific DNA sequence was selected and primers were designed to amplify 335 bp fragment from female sex while 16s ribosomal sequence was selected to design primers to amplify 468 bp PCR products both in male and female sex as an internal control. Nucleotide sequences of W chromosome specific DNA fragments of Khaki Campbell and Indian Runner breeds of duck were found to be identical both in size and sequences, The study concluded that the protocol was successful in precisely identifying the gender of ducklings belonging to both Indian Runner and Khaki Campbell breeds of ducks and duck embryosSER

Modelling the quantitative evaluation of soil nutrient supply, nutrient use efficiency, and fertilizer requirements of wheat in India

Wheat yields in many parts of India are stagnant. The main reason for this is conventional blanket fertilizer recommendation, lower fertilizer use efficiency, and imbalanced use of fertilizers. Estimation of fertilizer requirements based on quantitative approaches can assist in improving wheat yields and increasing nutrient use efficiency. We used the QUEFTS (QUantitative Evaluation of Fertility of Tropical Soils) model for estimation of nitrogen (N), phosphorus (P), and potassium (K) requirements and fertilizer recommendations for a target yield of wheat. The model considers the interactions of N, P, and K, and climate adjusted potential yield of the region. Published data from several field experiments dealing with N, P, and K conducted during the years 1970 to 1998 across wheat-growing environments of India, covering a wide range of soil and climatic conditions, were used to reflect the environmental variability. The relationships between indigenous N, P, and K supply and soil organic carbon, Olsen P, and ammonium acetate-extractable K, respectively, were established. The required N, P, and K accumulation in the plant for 1 tonne grain yield was 23.1, 3.5, and 28.5 kg, respectively, suggesting an average NPK ratio in the plant dry matter of about 6.6:1:8.1. The constants for minimum and maximum accumulation (kg grain kg-1) of N (27 and 60), P (162 and 390), and K (20 and 59) were derived as the standard model parameters in QUEFTS for fertilizer recommendation for irrigated wheat in the tropical and subtropical regions of India. Relationships of apparent recovery efficiencies of fertilizer N, P, and K with levels of their application were also determined. The observed yields of wheat with different amounts of these nutrients were in good agreement with the values predicted by the model, indicating that the model can be used for fertilizer recommendations

Suppressed Induction of Proinflammatory Cytokines by a Unique Metabolite Produced by Vibrio cholerae O1 El Tor Biotype in Cultured Host Cells ▿ †

Vibrio cholerae O1 has two biotypes, El Tor and Classical, and the latter is now presumed to be extinct in nature. Under carbohydrate-rich growth conditions, El Tor biotype strains produce the neutral fermentation end product 2,3-butanediol (2,3-BD), which prevents accumulation of organic acids from mixed acid fermentation and thus avoids a lethal decrease in the medium pH, while the Classical biotype strains fail to do the same. In this study, we investigated the inhibitory effect of 2,3-BD on the production of two proinflammatory biomarkers, intreleukin-8 (IL-8) and tumor necrosis factor alpha (TNF-α), in human intestinal epithelial HT29 and alveolar epithelial A549 cells. Cell-free culture supernatants of El Tor strain N16961 grown in LB supplemented with 1% glucose induced a negligible amount of IL-8 or TNF-α, while the Classical O395 strain induced much higher levels of these proinflammatory cytokines. On the other hand, three mutant strains constructed from the N16961 strain with defects in the constitutive 2,3-BD pathway were also able to induce high levels of cytokines. When HT29 and A549 cells were treated with bacterial flagella, known proinflammatory cytokine inducers, and chemically synthesized 2,3-BD at various concentrations, a dose-dependent decrease in IL-8 and TNF-α production was observed, demonstrating the suppressive effect of 2,3-BD on the production of proinflammatory cytokines in epithelial cells. Upon cotreatment with extraneous 2,3-BD, elevated levels of IκBα, the inhibitor of the NF-κB pathway, were detected in both HT29 and A549 cells. Furthermore, treatments containing 2,3-BD elicited lower levels of NF-κB-responsive luciferase activity, demonstrating that the reduced cytokine production is likely through the inhibition of the NF-κB pathway. These results reveal a novel and potential role of 2,3-BD as an immune modulator that might have conferred a superior pathogenic potential of the El Tor over the Classical biotype