188 research outputs found
Increased isolation of vibrio cholerae O1 serotype inaba over serotype ogawa in Pakistan
Although the predominant Vibrio cholerae serotype in Pakistan is Ogawa and serotype Inaba is rare, there has been a significant increase in the isolation of Inaba in our referral laboratory in Karachi. This paper reports this observation and further analysis of previous cholera data from 1993 to 2005 to assess the trend of occurrence and resistance pattern of V. cholerae strains. From January to September 2005, 245/3292 (7.4%) specimens yielded growth of V. cholerae. Of these, 243 were serotype Inaba, outnumbering serotype Ogawa. This recent Inaba strain is 100% resistant to cotrimoxazole, 3% resistant to chloramphenicol and not resistant to ampicillin, tetracycline and ofloxacin. This sensitivity pattern is almost similar to that of the previous predominant serotype Ogawa
Mitigation of load mismatch effects using an orthogonal load modulated balanced amplifier
This article presents an orthogonal load-modulated balanced amplifier designed to mitigate the effects of the load mismatch on the power-added efficiency and output power of the amplifier. This is achieved by electronically adjusting the ratio between the two input signals of the power amplifier (PA) (in phase and amplitude) and the reactive termination at the output nominally isolated port. The mode of operation of the PA is described using a theoretical analysis that highlights the role of the different tuning parameters and is confirmed by simulations using a simplified transistor model. The design and characterization under load mismatch of a prototype PA, working in the 1.6-3.2 GHz band are described and the experimental results compared to those of an analogous balanced PA, where it is shown that the orthogonal balanced amplifier is able to increase substantially the mismatch region on which a given target performance is achieved
Output signal re-injection in load modulated balanced amplifiers for RF bandwidth improvement
This letter discusses the theory, simulation, and experimental characterization of a load-modulated balanced amplifier (LMBA) where the control signal power (CSP) is obtained by re-injecting part of the output RF signal. Compared to the standard balanced load-modulated power amplifier (PA), this approach does not require an external amplification of the CSP. The potential of this technique is explored experimentally with a balanced PA (BPA) working on 1400-3400-MHz band, using an external off-the-shelf directional coupler and manual phase shift adjustment. The induced load modulation can lead to a 10% increase of power added efficiency, or 1 dB of output power, across the frequency band of operation compared to the BPA
Tetrazolylmethyl quinolines: design, docking studies, synthesis, anticancer and antifungal analyses
A new series of 2,5 and 1,5-regioisomers of the tetrazolyl group viz., 3-(5-benzyl/benzylthio-2H-tetrazol-2-yl) methyl-2-chloro-6-substituted quinoline 6h-q and 3-(5-benzyl/benzylthio-1H-tetrazol-1-yl) methyl-2-chloro-6-substituted quinolines 7h-q were synthesized. Docking studies of all these compounds with DNA as target using PDB: 1AU5 and 453D revealed that the compounds 6h and 6i act as covalent cross linker on the DNA helix of the former and intercalate the latter both with higher C score values. Another set of docking studies in the active pocket of dihydrofolate reductase and N-myristoyl transferase as targets to assess antifungal activity revealed that compounds 6k, 6l, 6p and 7q (with bromo and fluro substituents) showcases different binding modes and hydrogen bonding. Further, the compounds were screened for anticancer activity (primary cytotoxicity) against NCI-60 Human tumor cell line at a single high dose (10−5 M) concentration assay. Among the tested compounds, 6h has shown 99.28% of GI against Melanoma (SK-MEL-5) and compound 6i has shown 97.56% of GI against Breast Cancer (T-47D). Further, in vitro antifungal assay against A. fumigatus and C. albicans for these compounds 6h-q and 7h-q revealed potential to moderate activities as compared to the standard
Experiences, attitudes and barriers towards research amongst junior faculty of Pakistani medical universities
<p>Abstract</p> <p>Background</p> <p>The developing world has had limited quality research and in Pakistan, research is still in its infancy. We conducted a study to assess the proportion of junior faculty involved in research to highlight their attitude towards research, and identify the factors associated with their research involvement.</p> <p>Methods</p> <p>A cross-sectional study was conducted in four medical universities/teaching hospitals in Pakistan, representing private and public sectors. A pre-tested, self-administered questionnaire was used to collect information from 176 junior faculty members of studied universities/hospitals. Logistic regression analysis was used to identify factors related to attitudes and barriers in research among those currently involved in research with those who were not.</p> <p>Results</p> <p>Overall, 41.5% of study subjects were currently involved in research. A highly significant factor associated with current research involvement was research training during the post-graduate period (p < 0.001). Other factors associated with current involvement in research were male gender, working in the public sector and previous involvement in research. Overall, a large majority (85.2%) of doctors considered research helpful in their profession and had a positive attitude towards research; nevertheless this positive attitude was more frequently reported by doctors who were currently involved in research compared to those who were not (OR = 4.69; 95% CI = 1.54-14.26). Similarly, a large proportion (83.5%) of doctors considered research difficult to conduct; higher by doctors who were not presently involved in research (OR = 2.74; 95% CI = 1.20-6.22)</p> <p>Conclusion</p> <p>Less than half of the study participants were currently involved in research. Research output may improve if identified barriers are rectified. Further studies are recommended in this area.</p
Gender-Specific Modulation of the Response to Arterial Injury by Soluble Guanylate Cyclase α1
Objective: Soluble guanylate cyclase (sGC), a heterodimer composed of α and β subunits, synthesizes cGMP in response to nitric oxide (NO). NO modulates vascular tone and structure but the relative contributions of cGMP-dependent versus cGMP-independent mechanisms remain uncertain. We studied the response to vascular injury in male (M) and female (F) mice with targeted deletion of exon 6 of the sGCα1 subunit (sGCα1-/-), resulting in a non-functional heterodimer. Methods: We measured aortic cGMP levels and mRNA transcripts encoding sGC α1, α2, and β1 subunits in wild type (WT) and sGCa1-/- mice. To study the response to vascular injury, BrdU-incorporation and neointima formation (maximum intima to media (I/M) ratio) were determined 5 and 28 days after carotid artery ligation, respectively. Results: Aortic cGMP levels were 4-fold higher in F than in M mice in both genotypes, and, within each gender, 4-fold higher in WT than in sGCa1-/-. In contrast, sGCα1, sGCα2, and sGCβ1 mRNA expression did not differ between groups. 3H-thymidine incorporation in cultured sGCa1-/- smooth muscle cells (SMC) was 27%±12% lower than in WT SMC and BrdU-incorporation in carotid arteries 5 days after ligation was significantly less in sGCa1-/- M than in WT M. Neointima area and I/M 28 days after ligation were 65% and 62% lower in sGCa1-/- M than in WT M mice (p<0,05 for both) but were not different in F mice. Conclusion: Functional deletion of sGCa1 resulted in reduced cGMP levels in male sGCa1-/- mice and a gender-specific effect on the adaptive response to vascular injury
Common variants in CLDN2 and MORC4 genes confer disease susceptibility in patients with chronic pancreatitis
A recent Genome-wide Association Study (GWAS) identified association with variants in X-linked CLDN2 and MORC4 and PRSS1-PRSS2 loci with Chronic Pancreatitis (CP) in North American patients of European ancestry. We selected 9 variants from the reported GWAS and replicated the association with CP in Indian patients by genotyping 1807 unrelated Indians of Indo-European ethnicity, including 519 patients with CP and 1288 controls. The etiology of CP was idiopathic in 83.62% and alcoholic in 16.38% of 519 patients. Our study confirmed a significant association of 2 variants in CLDN2 gene (rs4409525—OR 1.71, P = 1.38 x 10-09; rs12008279—OR 1.56, P = 1.53 x 10-04) and 2 variants in MORC4 gene (rs12688220—OR 1.72, P = 9.20 x 10-09; rs6622126—OR 1.75, P = 4.04x10-05) in Indian patients with CP. We also found significant association at PRSS1-PRSS2 locus (OR 0.60; P = 9.92 x 10-06) and SAMD12-TNFRSF11B (OR 0.49, 95% CI [0.31–0.78], P = 0.0027). A variant in the gene MORC4 (rs12688220) showed significant interaction with alcohol (OR for homozygous and heterozygous risk allele -14.62 and 1.51 respectively, P = 0.0068) suggesting gene-environment interaction. A combined analysis of the genes CLDN2 and MORC4 based on an effective risk allele score revealed a higher percentage of individuals homozygous for the risk allele in CP cases with 5.09 fold enhanced risk in individuals with 7 or more effective risk alleles compared with individuals with 3 or less risk alleles (P = 1.88 x 10-14). Genetic variants in CLDN2 and MORC4 genes were associated with CP in Indian patients
Estrogen receptor transcription and transactivation: Basic aspects of estrogen action
Estrogen signaling has turned out to be much more complex and exciting than previously thought; the paradigm shift in our understanding of estrogen action came in 1996, when the presence of a new estrogen receptor (ER), ERβ, was reported. An intricate interplay between the classical ERα and the novel ERβ is of paramount importance for the final biological effect of estrogen in different target cells
Outcomes of obstructed abdominal wall hernia: results from the UK national small bowel obstruction audit
Background:
Abdominal wall hernia is a common surgical condition. Patients may present in an emergency with bowel obstruction, incarceration or strangulation. Small bowel obstruction (SBO) is a serious surgical condition associated with significant morbidity. The aim of this study was to describe current management and outcomes of patients with obstructed hernia in the UK as identified in the National Audit of Small Bowel Obstruction (NASBO).
Methods:
NASBO collated data on adults treated for SBO at 131 UK hospitals between January and March 2017. Those with obstruction due to abdominal wall hernia were included in this study. Demographics, co-morbidity, imaging, operative treatment, and in-hospital outcomes were recorded. Modelling for factors associated with mortality and complications was undertaken using Cox proportional hazards and multivariable regression modelling.
Results:
NASBO included 2341 patients, of whom 415 (17·7 per cent) had SBO due to hernia. Surgery was performed in 312 (75·2 per cent) of the 415 patients; small bowel resection was required in 198 (63·5 per cent) of these operations. Non-operative management was reported in 35 (54 per cent) of 65 patients with a parastomal hernia and in 34 (32·1 per cent) of 106 patients with an incisional hernia. The in-hospital mortality rate was 9·4 per cent (39 of 415), and was highest in patients with a groin hernia (11·1 per cent, 17 of 153). Complications were common, including lower respiratory tract infection in 16·3 per cent of patients with a groin hernia. Increased age was associated with an increased risk of death (hazard ratio 1·05, 95 per cent c.i. 1·01 to 1·10; P = 0·009) and complications (odds ratio 1·05, 95 per cent c.i. 1·02 to 1·09; P = 0·001).
Conclusion:
NASBO has highlighted poor outcomes for patients with SBO due to hernia, highlighting the need for quality improvement initiatives in this group
Run Away or Stick Together? The Impact of Organization-Specific Adverse Events on Alliance Partner Defection
Alliances are inter-organizational relationships wherein partners agree to engage in joint action and share benefits and burdens. But when might an adverse event that strikes one partner become too burdensome for another partner? Extant theories of alliance instability provide incomplete answers, which is problematic: for stricken organizations, anticipating whether their non-stricken partners will remain in the alliance can be essential for survival. Integrating insights from alliance dynamics and organizational stigma literatures, we theorize how an organization-specific adverse event affects a non-stricken partner's decision to continue with or defect from an alliance by considering factors that shift the balance between cohesive and disruptive forces. We propose that high stigmatization risk will increase the probability of partner defection through two disruptive mechanisms: relational uncertainty and stigma anxiety. Building on the idea that the same factors contributing to alliance formation may also condition partner defection, we theorize about the roles of partner resource interdependencies, relational embeddedness, and perceived partner similarity in amplifying or attenuating disruptive mechanisms triggered by an adverse event. We extend the research on partner defection and alliance instability by advancing an event-based view of alliance instability and specifying the conditions under which an alliance partner might defect
- …