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Studying turbulence structure near the wall in hydrodynamic flows:An approach based on the Schur decomposition of the velocity gradient tensor

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journal of Hydrodynamics 2022年第5期34卷 806-825页

作者： christopher j.Keylock School of Architecture Building and Civil EngineeringLoughborough UniversityLeicestershireUK

The Schur decomposition of the velocity gradient tensor(VGT)is an alternative to the classical Cauchy-Stokes decomposition into rotation rate and strain rate components.Recently,there have been several strands of work that have employed this decomposition to examine the physics of turbulence dynamics,including approaches that combine the Schur and Cauchy-Stokes formalisms.These are briefly reviewed before the latter approach is set out.This partitions the rotation rate and strain rate tensors into normal/local and non-normal/non-local contributions.We then study the relation between the VGT dynamics and ejection-sweep events in a channel flow boundary-layer.We show that the sweeps in particular exhibit novel behaviour compared with either the other quadrants,or the flow in general,with a much-reduced contribution to the dynamics from the non-normal terms above the viscous sub-layer.In particular,the reduction in the production term that is the interaction between the non-normality and the normal straining reduces in the log-layer as a consequence of an absence of alignment between the non-normal vorticity and the strain rate eigenvectors.There have been early forays into using the Schur transform approach for subgrid-scale modelling in large-eddy simulation(LES)and this would appear to be an exciting way forward.

关键词： Turbulence channel flow velocity gradient tensor Schur decomposition

Repeated hydrogen peroxide dosing briefly reduces cyanobacterial blooms and microcystin while increasing fecal bacteria indicators in a eutrophic pond

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journal of Environmental Sciences 2023年第2期124卷 522-543页

作者： Mark W.Lusty christopher j.Gobler School of Marine and Atmospheric Sciences Stony Brook UniversitySouthamptonNY 11968USA

This study explored the effects of H_(2)O_(2)on Cyanobacteria and non-target microbes using fluorometry,microscopy,flow cytometry,and high throughput DNA sequencing of the 16S rRNA gene during a series of mesocosm and whole-ecosystem experiments in a eutrophic pond in NY,USA.The addition of H_(2)O_(2)(8 mg/L)significantly reduced Cyanobacteria concentrations during a majority of experiments(66%;6 of 9)and significantly increased eukaryotic green and unicellular brown algae in 78%and 45%of experiments,respectively.While heterotrophic bacteria declined significantly following H_(2)O_(2)addition in all experiments,bacteria indicative of potential fecal contamination(Escherichia coli,Enterococcus,fecal coliform bacteria)consistently and significantly increased in response to H_(2)O_(2),evidencing a form of‘pollution swapping’.H_(2)O_(2)more effectively reduced Cyanobacteria in enclosed mesocosms compared to whole-ecosystem applications.Ten whole-pond H_(2)O_(2)applications over a twoyear period temporarily reduced cyanobacterial levels but never reduced concentrations below bloom thresholds and populations always rebounded in two weeks or less.The bacterial phyla of Cyanobacteria,Actinobacteria,and Planctomycetes were the most negatively impacted by H_(2)O_(2).Microcystis was always reduced by H_(2)O_(2),as was the toxin microcystin,but Microcystis remained dominant even after repeated H_(2)O_(2)treatments.Although H_(2)O_(2)favored the growth of eukaryotic algae over potentially harmful Cyanobacteria,the inability of H_(2)O_(2)to end cyanobacterial blooms in this eutrophic waterbody suggests it is a non-ideal mitigation approach in high biomass ecosystems and should be used judiciously due to potential negative impacts on non-target organisms and promotion of bacteria indicative of fecal contamination.

关键词： Indicator bacteria Toxic cyanobacteria Microcystin Microcystis Hydrogen peroxide Bacteria Enterococcus E.coli Pollution swapping

Functional nasal surgery in the office-based setting

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World journal of Otorhinolaryngology-Head and Neck Surgery 2023年第3期9卷 236-241页

作者： Alia j.Mowery christopher R.Razavi Department of Otolaryngology Johns Hopkins MedicineBaltimoreMarylandUSA Department of Otolaryngology School of MedicineOregon Health&Science UniversityPortlandOregonUSA

Objective:Nasal obstruction is a very common problem often addressed by functional nasal surgery.Increasingly,these procedures are being performed in the office setting secondary to decreased down time,cost,and obviation of general anesthesia.Our goal with this review is to discuss how to appropriately select patients for office-based procedures,what procedures may be considered,and current outcomes with in-office functional nasal surgery.Data Sources:PubMed,Scopus,Google Scholar.Methods:Research databases were searched for articles discussing techniques for performing functional nasal surgery in an office setting,and outcomes of various in-office functional nasal procedures.Results:Studies found and included in this review discuss many aspects of office-based functional nasal surgery,including practical points on patient selection and office set-up,what procedures can safely be performed,and outcomes of different techniques to address specific problems.Broadly,procedures amenable to performance in the office address the internal and external nasal valves,the nasal septum,and the inferior turbinates.Conclusion:A wide range of techniques to aaddress the nasal valves,septum,and inferior turbinates can be performed in a safe and effective manner without the need for an operative suite.

关键词： nasal obstruction nasal surgical procedures office surgery reconstructive surgery

Development process for a higher capacity Propsetter~ system

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International journal of Mining Science and Technology 2018年第1期28卷 121-126页

作者： christopher j.Brown Product Development-Strata Worldwide LLC

As longwall tailgate support technologies continue to be developed and improved, strata worldwide has worked to design and manufacture a revised Propsetter to provide additional support capacity and enable applications at greater mine heights.The support is targeted for tailgate applications, however, it can also be utilized for roof support in various types of mining environments.This paper describes the design changes for enhancing the support capacity of the Propsetter to more closely align its performance with other support technologies currently being employed in longwall tailgates.Balancing changes to each design aspect of the Propsetter was key to successfully improving the roof support's load capacity while maintaining controlled deformation.Increasing the load capacity would allow a mine to improve support efficiency with a smaller, less intrusive support compared to support alternatives and reduce the cost per foot of supported entry.The target support capacity was 711–890 k N at 50 mm of deformation to more closely match the performance of competing tailgate supports such as the 610 mm-diameter CAN~.To achieve this goal, changes were made to all design aspects of the Propsetter: diameter, wedge cut depth and angle, pod size, and confinement rings.Test results from the NIOSH Mine Roof Simulator verified that these design changes were successful in increasing the capacity of the Propsetter to the 711–890 k N range at fifty mms of deformation.

关键词： Propsetter Can Longwall mining Tailgate roof support Controlled deformation

Plasma-catalysis: Is it just a question of scale?

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Frontiers of Chemical Science and Engineering 2019年第2期13卷 264-273页

作者： j.christopher Whitehead School of Chemistry The University of ManchesterManchester M13 9PLUK

The issues of describing and understanding the changes in performance that result when a catalyst is placed into plasma are discussed. The different chemical and physical interactions that result and how their combination might produce beneficial results for the plasma-catalytic processing of different gas streams are outlined with particular emphasis being placed on the different range of spatial and temporal scales that must be considered both in experiment and modelling. The focus is on non-thermal plasma where the lack of thermal equilibrium creates a range of temperature scales that must be considered. This contributes in part to a wide range of inhomogeneity in different properties such as species concentrations and electric fields that must be determined experimentally by in situ methods and be incorporated into modelling. It is concluded that plasmacatalysis is best regarded as conventional catalysis perturbed by the presence of a discharge, which modifies its operating conditions, properties and outcomes often in a very localised way. The sometimes used description "plasma-activated catalysis" is an apt one.

关键词： plasma catalysis plasma-activated catalysis non-thermal plasma CO2 conversion

Food Safety and Health—Past Problems and Future Solutions

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Engineering 2020年第4期6卷 384-388页

作者： christopher j.Smith Department of Clinical Sciences and Nutrition University of ChesterChester CH14BJUK

The dictum of Hippocrates“Let thy food be thy medicine and medicine be thy food”is potentially both more accurate and more dangerous than ever before.This dictum can only be realistically applied if all foods are known to be safe.Nowadays foods are being produced,which are processed in a variety of ways with ingredients sourced from many different countries and processed in a variety of ways.This processing may include the addition of supplements which are intended to improve health and of adulterants which are potentially harmful.Additionally,foods may be contaminated with pesticides and other materials encountered during production and processing.Thus there is a need to identify“unsafe”foods.The question may be better put as:Which foods are safe?

关键词： pesticides intended dangerous

Efficacy and dose response of Lactiplantibacillus plantarum in diarrhea-predominant irritable bowel syndrome

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World journal of Gastroenterology 2023年第28期29卷 4451-4465页

作者： christopher j Martoni Shalini Srivastava Anders Damholt Gregory j Leyer Clinical Development Human HealthChr.Hansen A/SHoersholm 2970Denmark Clinical Development Vedic LifesciencesMumbai 400053India Scientific Affairs Human HealthChr.Hansen A/SHoersholm 2970Denmark

BACKGROUND Probiotics have shown promise in alleviating symptoms of diarrhea-predominant irritable bowel syndrome(IBS-D);however,the certainty of evidence is low.Wellpowered randomized controlled dose-ranging trials are warranted on promising single-strain candidates.AIM To investigate the clinical efficacy of Lactiplantibacillus plantarum(L.plantarum)Lpla33(DSM34428)in adults with IBS-D.METHODS This is a randomized,double-blind,placebo-controlled,multi-center,and doseranging study.Three hundred and seven adults,18-70 years of age,with IBS-D,according to Rome IV criteria,were allocated(1:1:1)to receive placebo or L.plantarum Lpla33 at 1×10^(9)(1B)or 1×10^(10)(10B)colony-forming units/d over an 8-wk intervention period.The primary outcome was the change in IBS severity scoring system(IBS-SSS)total score after 8 wk,while secondary and exploratory outcomes included abdominal pain severity,IBS related quality of life,stool and microbial profile,and perceived stress.RESULTS IBS-SSS was significantly reduced,after 8 wk,in participants receiving L.plantarum 1B(-128.45±83.30;P<0.001)and L.plantarum 10B(-156.77±99.06;P<0.001),compared to placebo(-58.82±74.75).Further,a dose-ranging effect was observed,with a greater absolute reduction in the L.plantarum 10B group(P<0.05).A reduction in sub-scores related to abdominal pain,abdominal distension,bowel habits,and quality of life was observed in both L.plantarum groups compared to placebo(P<0.001).Further,62.5%and 88.4%of participants administered L.plantarum 1B and 10B,respectively,were classified as stool consistency responders based on a reduction in diarrheal stool form,as compared to 26.3%in the placebo group(P<0.001).In contrast,no significant shifts were observed in microbial diversity.CONCLUSION L.plantarum Lpla33(DSM34428)is well tolerated and improves IBS symptom severity with a dose-ranging effect and a corresponding normalization of bowel habits in adults with IBS-D.

关键词： Randomized clinical trial Diarrhea-predominant irritable bowel syndrome Microbiome Probiotic Lactiplantibacillus plantarum

Phalloplasty following penectomy for penile cancer

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Asian journal of Urology 2022年第4期9卷 460-466页

作者： Wai Gin Lee A.Nim christopher David j.Ralph University College London Hospital LondonUnited Kingdom St Peter’s Andrology LondonUnited Kingdom

Objective:Penile reconstruction or phalloplasty following penectomy can be offered where the functional penile length is inadequate for a man to void while standing or to have sexual intercourse.Phalloplasty is usually staged due to the complex surgical techniques required.This narrative review describes the technical concepts and summarises the contemporary outcomes following phalloplasty in this challenging cohort.Methods:A retrospective review of the English literature was performed between january 1946 till November 2021.The data were synthesised and complemented by the expert opinion of the authors with 20 years of experience in this field.The flaps are ideally designed with an integrated urethra or alternatively,a further free flap urethroplasty can be offered.Phallo-plasty is further complicated following penectomy by scarring from the previous surgery and the potential loss of structures that would normally be present at the recipient site.Results:There are limited published data with a total of 19 men recorded in the literature.Only the radial artery forearm free flap and anterolateral thigh flap have been described in this cohort of patients.Functional outcomes including standing micturition,sensation in the neo-phallus,and the ability to orgasm are good.Overall quality of life and satisfaction was also good despite the high risk for long-term complications of the neophallus and donor site.Conclusion:Phalloplasty following penectomy requires microsurgical transfer of a free flap or a pedicled flap to reconstruct a neophallus.An erectile device is inserted at a later stage to facilitate sexual intercourse,if desired.Surgical scarring from penectomy and the potential loss of vasculature that would normally be present at the recipient site may further complicate reconstruction.Surgical and functional outcomes are acceptable based on the limited published experience to date.

关键词： Humans Male Myocutaneous flap or transplantation Penis or surgery Phalloplasty Reconstructive surgical procedures Retrospective study Surgical flap Thigh or surgery Treatment outcome Urethra or surgery

Rhythms of chloroplast magnesium import contribute to daily metabolic feedback

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Molecular Plant 2022年第11期15卷 1659-1661页

作者： Xiang Li christopher R.Buckley Michael j.Haydon School of BioSciences University of MelbourneParkvilleVIC 3010Australia

Organisms have evolved stable yet dynamic circadian systems to coordinate biological rhythms that contribute to fitness.Circadian oscillators generate rhythms via transcriptional and post-transcriptional control of key cellular processes such as metabolism and nutrient transport that fluctuate across the course of the day.In addition,intracellular ions and metabolites can act as signaling molecules and protein cofactors that provide feedback to fine-tune biological timekeeping(Haydon et al.,2013).

关键词： magnesium metabolism coordinate