419 research outputs found

    Isolating the non-polar contributions to the intermolecular potential for water-alkane interactions

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    Intermolecular potential models for water and alkanes describe pure component properties fairly well, but fail to reproduce properties of water-alkane mixtures. Understanding interactions between water and non-polar molecules like alkanes is important not only for the hydrocarbon industry but has implications to biological processes as well. Although non-polar solutes in water have been widely studied, much less work has focused on water in non-polar solvents. In this study we calculate the solubility of water in different alkanes (methane to dodecane) at ambient conditions where the water content in alkanes is very low so that the non-polar water-alkane interactions determine solubility. Only the alkane-rich phase is simulated since the fugacity of water in the water rich phase is calculated from an accurate equation of state. Using the SPC/E model for water and TraPPE model for alkanes along with Lorentz-Berthelot mixing rules for the cross parameters produces a water solubility that is an order of magnitude lower than the experimental value. It is found that an effective water Lennard-Jones energy εW/k = 220 K is required to match the experimental water solubility in TraPPE alkanes. This number is much higher than used in most simulation water models (SPC/E—εW/k = 78.2 K). It is surprising that the interaction energy obtained here is also higher than the water-alkane interaction energy predicted by studies on solubility of alkanes in water. The reason for this high water-alkane interaction energy is not completely understood. Some factors that might contribute to the large interaction energy, such as polarizability of alkanes, octupole moment of methane, and clustering of water at low concentrations in alkanes, are examined. It is found that, though important, these factors do not completely explain the anomalously strong attraction between alkanes and water observed experimentally

    Retrospective analysis of intrauterine granulocyte colony-stimulating factor in controlled ovarian stimulation with intrauterine insemination cycle

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    Background: Persistent thin endometrium affects <1% of patients. Various treatments have been proposed with no satisfactory results. GCSF is one such treatment modality which improves endometrial thickness and implantation. Aim of this study was to analyse the effects of dose and the site of instilling intrauterine G-CSF in COS IUI cycles in patients with unexplained infertility and to note the pregnancy rates among them.Methods: It is a 3-year retrospective study done in obstetrics and gynecology department of AJ Institute of Medical Sciences and Research Centre, that included all unexplained infertility cycles with controlled ovulation stimulation-IUI protocols where for a thin endometrium GCSF was used. The method of ovarian stimulation, the drug and dose used, the trigger for ovulation and the ovarian and endometrial response was noted. The day of the intrauterine GCSF and the dose and the site of instillation was noted. The endometrial response to GCSF the outcome for pregnancy was noted. All the data was analyzed statistically.Results: Significant endometrial response was seen with a dose of 100 mg,150 mg and 300 mg. Pregnancy outcome was better when GCSF was instilled just above the level of the os. GCSF instilled at the level of the fundus increases the possibility of ectopic pregnancy.Conclusions: Instillation of GCSF of 100 mg dosage just above the os; is a safe and effective method for improving the endometrial thickness and increasing pregnancy rate

    Effect of growing cotton in rotation with different crops on structure of black cotton soil

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    Results of an investigation carried out to study the effect of growing cotton in rotation with juar and groundnut on the structure of black cotton soil are presented and discussed. The rotations studied were:- (a) Cotton grown continuously year after year; (b) Cotton and juar grown in alternate years; and (c) Cotton-juar-groundnut in three course rotation. Determinations made for evaluation of structure and the ranges of values obtained were:- (i) Degree of aggreation - 64.4-69.3 (ii) Single value figure for surface area - 587.6-595.7 (iii) Dispersion coefficient - 805-9.0 (iv) Volume weight - 1.11-1.14 (v) Total pore space - 58.3-60.1% (vi) Volume of large pores - 20.2-21.6% (vii) Rate of percolation through undistrubed soil core samples - 1.9-3.9 inch per hr. (viii) Rate of percolation through distrubed soil samples - 2.7-2.9 inch per hr. No significant differences in the structural condition of the soil were observed in plots under the three different rotations, both in 0-6" and 6-12" layers. The lower 6-12" layer did not show any structural difference from the surface 0-6" layer. None of the standing crops of the year,i.e., cotton, juar and groundnut showed any pronounced effect on the structure of the soil

    Purification and characterization of prophenoloxidase from cotton bollworm, Helicoverpa armigera

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    Phenoloxidases are oxidative enzymes, which play an important role in both cell mediated and humoral immunity. Purification and biochemical characterization of prophenoloxidase from cotton bollworm, Helicoverpa armigera (Hübner) were carried out to study its biochemical properties. Prophenoloxidase consists of a single polypeptide chain with a relative molecular weight of 85 kDa as determined by SDS–PAGE, MALDI–TOF MS and LC–ESI MS. After the final step, the enzyme showed 71.7 fold of purification with a recovery of 49.2%. Purified prophenoloxidase showed high specific activity and homology with phenoloxidase subunit-1 of Bombyx mori and the conserved regions of copper binding (B) site of phenoloxidase. Purified prophenoloxidase has pH optima of 6.8 and has high catalytic efficiency towards the dopamine as a substrate in comparison to catechol and L-Dopa. The PO activity was strongly inhibited by phenylthiourea, thiourea, dithiothreitol and kojic acid

    Reconstruction of ancient microbial genomes from the human gut

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    Loss of gut microbial diversity1–6 in industrial populations is associated with chronic diseases7, underscoring the importance of studying our ancestral gut microbiome. However, relatively little is known about the composition of pre-industrial gut microbiomes. Here we performed a large-scale de novo assembly of microbial genomes from palaeofaeces. From eight authenticated human palaeofaeces samples (1,000–2,000 years old) with well-preserved DNA from southwestern USA and Mexico, we reconstructed 498 medium- and high-quality microbial genomes. Among the 181 genomes with the strongest evidence of being ancient and of human gut origin, 39% represent previously undescribed species-level genome bins. Tip dating suggests an approximate diversification timeline for the key human symbiont Methanobrevibacter smithii. In comparison to 789 present-day human gut microbiome samples from eight countries, the palaeofaeces samples are more similar to non-industrialized than industrialized human gut microbiomes. Functional profiling of the palaeofaeces samples reveals a markedly lower abundance of antibiotic-resistance and mucin-degrading genes, as well as enrichment of mobile genetic elements relative to industrial gut microbiomes. This study facilitates the discovery and characterization of previously undescribed gut microorganisms from ancient microbiomes and the investigation of the evolutionary history of the human gut microbiota through genome reconstruction from palaeofaeces.Ethics Overview of samples Reference-based taxonomic composition De novo genome reconstruction Methanobrevibacter smithii tip dating Functional genomic analysis Discussion Online content Method

    An Open-Label Phase II Study Evaluating the Safety and Efficacy of Ramucirumab Combined With mFOLFOX-6 as First-Line Therapy for Metastatic Colorectal Cancer

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    Background.Vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR-2) are believed to mediate angiogenesis in colorectal cancer (CRC). Ramucirumab (RAM; IMC-1121B) is a human IgG1 monoclonal antibody that inhibits VEGF ligand binding to VEGFR-2, inhibiting VEGFR-2 activation and signaling.Methods.Patients with metastatic CRC, Eastern Cooperative Oncology Group performance status 0–1, and adequate organ function who had not received chemotherapy for metastatic disease received RAM and the modified FOLFOX-6 regimen every 2 weeks. Endpoints included progression-free survival (PFS), objective response rate, overall survival, and safety. The sample size was based on a potentially improved median PFS from 8 months to 11 months.Results.Forty-eight patients received therapy. Median PFS was 11.5 months (95% confidence interval [CI]: 8.6–13.1 months). The objective response rate was 58.3% (95% CI: 43.21–72.39). The disease control rate (complete or partial response plus stable disease) was 93.8% (95% CI: 82.8–98.7). Median overall survival was 20.4 months (95% CI: 18.5–25.1 months). The most frequent grade 3–4 adverse events included neutropenia (grade 3: 33.3%; grade 4: 8.3%), hypertension (grade 3: 16.7%), and neuropathy (grade 3: 12.5%). Two patients died during the study due to myocardial infarction and cardiopulmonary arrest.Conclusion.RAM may enhance the efficacy of modified FOLFOX-6 chemotherapy with an acceptable safety profile in metastatic CRC

    Intracardiac echocardiography to guide transseptal catheterization for radiofrequency catheter ablation of left-sided accessory pathways: two case reports

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    Intracardiac echocardiography (ICE) is a useful tool for guiding transseptal puncture during electrophysiological mapping and ablation procedures. Left-sided accessory pathways (LSAP) can be ablated by using two different modalities: retrograde approach through the aortic valve and transseptal approach with puncture of the fossa ovalis. We shall report two cases of LSAP where transcatheter radiofrequency ablation (TCRFA) was firstly attempted via transaortic approach with ineffective results. Subsequently, a transseptal approach under ICE guidance has been performed. During atrial septal puncture ICE was able to locate the needle tip position precisely and provided a clear visualization of the "tenting effect" on the fossa ovalis. ICE allowed a better mapping of the mitral ring and a more effective catheter ablation manipulation and tip contact which resulted in a persistent and complete ablation of the accessory pathway with a shorter time of fluoroscopic exposure. ICE-guided transseptal approach might be a promising modality for TCRFA of LSAP

    Serum immunoglobulin G, M and A response to Cryptosporidium parvum in Cryptosporidium-HIV co-infected patients

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    <p>Abstract</p> <p>Background</p> <p><it>Cryptosporidium parvum</it>, the protozoan parasite, causes a significant enteric disease in immunocompromised hosts such as HIV patients. The present study was aimed to compare serum IgG, IgM and IgA responses to crude soluble antigen of <it>C. parvum </it>in HIV seropositive and seronegative patients co-infected with <it>Cryptosporidium </it>and to correlate the responses with symptomatology.</p> <p>Methods</p> <p><it>Cryptosporidium parvum </it>specific serum antibody (IgG, IgM and IgA) responses were assessed by ELISA in 11 HIV seropositive <it>Cryptosporidium </it>positive (Group I), 20 HIV seropositive <it>Cryptosporidium </it>negative (Group II), 10 HIV seronegative <it>Cryptosporidium </it>positive (Group III), 20 HIV seronegative <it>Cryptosporidium </it>negative healthy individuals (Group IV) and 25 patients with other parasitic diseases (Group V).</p> <p>Results</p> <p>A positive IgG and IgA antibody response was observed in significantly higher number of <it>Cryptosporidium </it>infected individuals (Gp I and III) compared to <it>Cryptosporidium </it>un-infected individuals (Gp II, IV and V) irrespective of HIV/immune status. Sensitivity of IgG ELISA in our study was found to be higher as compared to IgM and IgA ELISA. The number of patients with positive IgG, IgM and IgA response was not significantly different in HIV seropositive <it>Cryptosporidium </it>positive patients with diarrhoea when compared to patients without diarrhoea and in patients with CD4 counts <200 when compared to patients with CD4 counts >200 cells/μl.</p> <p>Conclusion</p> <p>The study showed specific serum IgG and IgA production in patients infected with <it>Cryptosporidium</it>, both HIV seropositive and seronegative as compared to uninfected subjects suggesting induction of <it>Cryptosporidium </it>specific humoral immune response in infected subjects. However, there was no difference in number of patients with positive response in HIV seropositive or seronegative groups indicating that HIV status may not be playing significant role in modulation of <it>Cryptosporidium </it>specific antibody responses. The number of patients with positive IgG, IgM and IgA response was not significantly different in patients with or without history of diarrhoea thereby indicating that <it>Cryptosporidium </it>specific antibody responses may not be necessarily associated with protection from symptomatology.</p
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