59 research outputs found
Assessment of Laws of the Wall During FlameβWall Interaction of Premixed Flames Within Turbulent Boundary Layers
\ua9 The Author(s) 2024. The validity of the usual laws of the wall for Favre mean values of the streamwise velocity component and temperature for non-reacting flows has been assessed for turbulent premixed flame-wall interaction using Direct Numerical Simulation (DNS) data. Two different DNS databases corresponding to friction velocity-based Reynolds number of 110 and 180 representing unsteady head-on quenching of statistically planar flames within turbulent boundary layers have been considered. The usual log-law based expressions for the Favre mean values of the streamwise velocity and temperature for the inertial layer have been found to be inadequate at capturing the corresponding variations obtained from DNS data. The underlying assumptions of constant shear stress and the equilibrium of production and dissipation of turbulent kinetic energy underpinning the derivation of the usual log-law for the mean streamwise velocity have been found to be rendered invalid within the usual inertial layer during flame-wall interaction for both cases considered here. The heat flux does not remain constant within the usual inertial layer, and the turbulent flux of temperature exhibits counter-gradient transport within the so-called inertial layer for the cases considered in this work. These render the assumptions behind the derivation of the usual log-law for temperature to be invalid for application to turbulent flame-wall interaction. It has been found that previously proposed empirical modifications to the existing laws of the wall, which account for density and kinematic viscosity variations with temperature, do not significantly improve the agreement with the corresponding DNS data in the inertial layer and the inaccurate approximations for the kinematic viscosity compensated wall normal distance and the density compensated streamwise velocity component contribute to this disagreement. The DNS data has been utilised here to propose new expressions for the kinematic viscosity compensated wall normal distance and the density compensated streamwise velocity component, which upon using in the empirically modified law of wall expressions have been demonstrated to provide reasonable agreement with DNS data
Mesh-Free Laparoscopic High Uterosacral Ligament Suspension during Total Laparoscopic Hysterectomy for Uterine Prolapse.
STUDY OBJECTIVE: To demonstrate a mesh-free approach for uterine prolapse during a hysterectomy. DESIGN: Technical video (Canadian Task Force classification III). SETTING: Benign gynecology department at a university hospital. PATIENT: A 50-year-old woman. INTERVENTION: Laparoscopic high uterosacral ligament suspension technique. MEASUREMENTS AND MAIN RESULTS: A 50-year-old woman presented with irregular vaginal bleeding and grade 3 uterine prolapse. The patient was concerned regarding the use of mesh and erosion. After counseling the patient agreed to a mesh-free single procedure. The use of mesh for the treatment of pelvic organ prolapse has become the subject of controversy and litigation. Complications of mesh erosion have resulted in the US Food and Drug Administration reclassifying transvaginal meshes as high-risk devices in 2016 [1]. Mesh erosion risk is up to 23% with hysterectomy and concomitant laparoscopic sacrocolpopexy [2] and 3% with sacrohysteropexy [3]. We present an alternative laparoscopic approach of treating uterine prolapse with high uterosacral suspension during laparoscopic hysterectomy. Our method avoids the use of mesh, sacrocervicopexy and morcellation, or an interval sacrocolpopexy. Although high uterosacral ligament suspension can be performed vaginally, it carries up to an 11% risk of ureteric injury [4]. CONCLUSION: In this video a bilateral ureterolysis is performed, before hysterectomy, isolating the uterosacral ligaments. These are then suspended to the vaginal vault in a purse-string fashion using Vicryl 0 (polyglactin 910) and intracorporeal knot-tying. Postprocedure the vault is well supported with a vaginal length of 12βcm
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A systematic review highlighting poor quality of evidence for content validity of quality of life instruments in female chronic pelvic pain.
OBJECTIVES: To evaluate the content validity of 19 patient-reported outcome measures (PROMs) used to measure quality of life (QoL) in women with chronic pelvic pain (CPP). STUDY DESIGN AND SETTING: We searched Embase, MEDLINE, PsycINFO databases and Google Scholar from inception to August 2020. We included records describing the development or studies assessing content validity of PROMs. Two reviewers independently assessed the methodological quality of PROMs using the Consensus-based Standards for the Selection of Health Measurement Instruments checklist. Evidence was synthesized for relevance, comprehensiveness, and comprehensibility. Quality of evidence was rated using a modified Grading of Recommendations, Assessment, Development, and Evaluations approach. RESULTS: PROM development was inadequate for all instruments included in this review. No high-quality evidence ratings were found for relevance, comprehensiveness, and comprehensibility. QoL was measured using generic instruments (68.42%, 13/19) rather than those specific to chronic pain (21.04%, 4/19) or pelvic pain (10.53%, 2/19). Quality of concept elicitation was inadequate for 90% of PROMs. Half of PROMs did not include patients in their development and only 40% were devised using a sample representative of the target population for which the PROM was developed. Cognitive interviews were conducted in one-fifth of PROMs and were mostly of inadequate/doubtful quality. CONCLUSION: There is poor quality of evidence for content validity of PROMs used to measure QoL in women with CPP
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A meta-synthesis of qualitative literature on female chronic pelvic pain for the development of a core outcome set: a systematic review.
INTRODUCTION AND HYPOTHESIS: Qualitative research has an increasing role in the development of core outcome sets (COS) adding patient perspectives to the considerations of core outcomes. We aimed to identify priorities of women with experience of chronic pelvic pain (CPP). METHODS: The search strategy was a systematic review of qualitative studies identified from Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL, EMBASE, MEDLINE and PsycInfo databases. Selection criteria were qualitative studies exploring the experience of women with CPP. Two independent researchers extracted data and summarized findings using thematic analysis. A CERQual assessment was performed to assess the confidence of review findings. RESULTS: We identified pertinent issues affecting women with CPP including the lack of holistic care, influence of psychosocial factors and the impact of pain on quality of life. Five meta-themes central to delivering a patient-centred approach were highlighted: acceptance of pain, quality of life, management of CPP, communication and support. Management of CPP was the most commonly reported meta-theme across seven studies and half of studies reported quality of life, management, communication and support. Quality appraisal of included studies identified only a single study that met all CASP (Critical Appraisal Skills Programme) criteria. There was high confidence in the evidence for acceptance of pain, quality of life and communication meta-themes. CONCLUSION: Meta-themes revealed by this review should be considered as a priority and reflected in outcomes reported by future studies evaluating interventions for CPP. In addition, these themes should be considered by clinicians managing women with CPP
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Evaluation of clinical practice guidelines (CPG) on the management of female chronic pelvic pain (CPP) using the AGREE II instrument.
INTRODUCTION AND HYPOTHESIS: Variations in guidelines may result in differences in treatments and potentially poorer health-related outcomes. We aimed to systematically review and evaluate the quality of national and international guidelines and create an inventory of CPG recommendations on CPP. METHODS: We searched EMBASE and MEDLINE databases from inception till August 2020 as well as websites of professional organizations and societies. We selected national and international CPGs reporting on the diagnosis and management of female CPP. We included six CPGs. Five researchers independently assessed the quality of included guidelines using the AGREE II tool and extracted recommendations. RESULTS: Two hundred thirty-two recommendations were recorded and grouped into six categories: diagnosis, medical treatment, surgical management, behavioural interventions, complementary/alternative therapies and education/research. Thirty-nine (17.11%) recommendations were comparable including: a comprehensive pain history, a multi-disciplinary approach, attributing muscular dysfunction as a cause of CPP and an assessment of quality of life. Two guidelines acknowledged sexual dysfunction associated with CPP and recommended treatment with pelvic floor exercises and behavioural interventions. All guidelines recommended surgical management; however, there was no consensus regarding adhesiolysis, bilateral salpingo-oophorectomy during hysterectomy, neurectomy and laparoscopic uterosacral nerve ablation. Half of recommendations (106, 46.49%) were unreferenced or made in absence of good-quality evidence or supported by expert opinion. Based on the AGREE II assessment, two guidelines were graded as high quality and recommended without modifications (EAU and RCOG). Guidelines performed poorly in the "Applicability", "Editorial Independence" and "Stakeholder Involvement" domains. CONCLUSION: Majority of guidelines were of moderate quality with significant variation in recommendations and quality of guideline development
New Abundant Microbial Groups in Aquatic Hypersaline Environments
We describe the microbiota of two hypersaline saltern ponds, one of intermediate salinity (19%) and a NaCl saturated crystallizer pond (37%) using pyrosequencing. The analyses of these metagenomes (nearly 784β
Mb) reaffirmed the vast dominance of Haloquadratum walsbyi but also revealed novel, abundant and previously unsuspected microbial groups. We describe for the first time, a group of low GC Actinobacteria, related to freshwater Actinobacteria, abundant in low and intermediate salinities. Metagenomic assembly revealed three new abundant microbes: a low-GC euryarchaeon with the lowest GC content described for any euryarchaeon, a high-GC euryarchaeon and a gammaproteobacterium related to Alkalilimnicola and Nitrococcus. Multiple displacement amplification and sequencing of the genome from a single archaeal cell of the new low GC euryarchaeon suggest a photoheterotrophic and polysaccharide-degrading lifestyle and its relatedness to the recently described lineage of Nanohaloarchaea. These discoveries reveal the combined power of an unbiased metagenomic and single cell genomic approach
GABA Maintains the Proliferation of Progenitors in the Developing Chick Ciliary Marginal Zone and Non-Pigmented Ciliary Epithelium
GABA is more than the main inhibitory neurotransmitter found in the adult CNS. Several studies have shown that GABA regulates the proliferation of progenitor and stem cells. This work examined the effects of the GABAA receptor system on the proliferation of retinal progenitors and non-pigmented ciliary epithelial (NPE) cells. qRT-PCR and whole-cell patch-clamp electrophysiology were used to characterize the GABAA receptor system. To quantify the effects on proliferation by GABAA receptor agonists and antagonists, incorporation of thymidine analogues was used. The results showed that the NPE cells express functional extrasynaptic GABAA receptors with tonic properties and that low concentration of GABA is required for a baseline level of proliferation. Antagonists of the GABAA receptors decreased the proliferation of dissociated E12 NPE cells. Bicuculline also had effects on progenitor cell proliferation in intact E8 and E12 developing retina. The NPE cells had low levels of the Clβtransporter KCC2 compared to the mature retina, suggesting a depolarising role for the GABAA receptors. Treatment with KCl, which is known to depolarise membranes, prevented some of the decreased proliferation caused by inhibition of the GABAA receptors. This supported the depolarising role for the GABAA receptors. Inhibition of L-type voltage-gated Ca2+ channels (VGCCs) reduced the proliferation in the same way as inhibition of the GABAA receptors. Inhibition of the channels increased the expression of the cyclin-dependent kinase inhibitor p27KIP1, along with the reduced proliferation. These results are consistent with that when the membrane potential indirectly regulates cell proliferation with hyperpolarisation of the membrane potential resulting in decreased cell division. The increased expression of p27KIP1 after inhibition of either the GABAA receptors or the L-type VGCCs suggests a link between the GABAA receptors, membrane potential, and intracellular Ca2+ in regulating the cell cycle
Gene-Specific Signatures of Elevated Non-Synonymous Substitution Rates Correlate Poorly across the Plasmodium Genus
BACKGROUND: Comparative genome analyses of parasites allow large scale investigation of selective pressures shaping their evolution. An acute limitation to such analysis of Plasmodium falciparum is that there is only very partial low-coverage genome sequence of the most closely related species, the chimpanzee parasite P. reichenowi. However, if orthologous genes have been under similar selective pressures throughout the Plasmodium genus then positive selection on the P. falciparum lineage might be predicted to some extent by analysis of other lineages. PRINCIPAL FINDINGS: Here, three independent pairs of closely related species in different sub-generic clades (P. falciparum and P. reichenowi; P. vivax and P. knowlesi; P. yoelii and P. berghei) were compared for a set of 43 candidate ligand genes considered likely to be under positive directional selection and a set of 102 control genes for which there was no selective hypothesis. The ratios of non-synonymous to synonymous substitutions (dN/dS) were significantly elevated in the candidate ligand genes compared to control genes in each of the three clades. However, the rank order correlation of dN/dS ratios for individual candidate genes was very low, less than the correlation for the control genes. SIGNIFICANCE: The inability to predict positive selection on a gene in one lineage by identifying elevated dN/dS ratios in the orthologue within another lineage needs to be noted, as it reflects that adaptive mutations are generally rare events that lead to fixation in individual lineages. Thus it is essential to complete the genome sequences of particular species of phylogenetic importance, such as P. reichenowi
Genomic analysis and temperature-dependent transcriptome profiles of the rhizosphere originating strain Pseudomonas aeruginosa M18
<p>Abstract</p> <p>Background</p> <p>Our previously published reports have described an effective biocontrol agent named <it>Pseudomonas </it>sp. M18 as its 16S rDNA sequence and several regulator genes share homologous sequences with those of <it>P. aeruginosa</it>, but there are several unusual phenotypic features. This study aims to explore its strain specific genomic features and gene expression patterns at different temperatures.</p> <p>Results</p> <p>The complete M18 genome is composed of a single chromosome of 6,327,754 base pairs containing 5684 open reading frames. Seven genomic islands, including two novel prophages and five specific non-phage islands were identified besides the conserved <it>P. aeruginosa </it>core genome. Each prophage contains a putative chitinase coding gene, and the prophage II contains a <it>capB </it>gene encoding a putative cold stress protein. The non-phage genomic islands contain genes responsible for pyoluteorin biosynthesis, environmental substance degradation and type I and III restriction-modification systems. Compared with other <it>P. aeruginosa </it>strains, the fewest number (3) of insertion sequences and the most number (3) of clustered regularly interspaced short palindromic repeats in M18 genome may contribute to the relative genome stability. Although the M18 genome is most closely related to that of <it>P. aeruginosa </it>strain LESB58, the strain M18 is more susceptible to several antimicrobial agents and easier to be erased in a mouse acute lung infection model than the strain LESB58. The whole M18 transcriptomic analysis indicated that 10.6% of the expressed genes are temperature-dependent, with 22 genes up-regulated at 28Β°C in three non-phage genomic islands and one prophage but none at 37Β°C.</p> <p>Conclusions</p> <p>The <it>P. aeruginosa </it>strain M18 has evolved its specific genomic structures and temperature dependent expression patterns to meet the requirement of its fitness and competitiveness under selective pressures imposed on the strain in rhizosphere niche.</p
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