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Microbial stabilisation and kinetic enhancement of marine methane hydrates in both deionised-and sea-water

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Petroleum 2021年第4期7卷 402-406页

作者： Mohammad Reza Ghaani jonathan M.Young Prithwish K.nandi Shamsudeen Dandare christopher c.rallen.n.all j.en.lish School of chemical and Bioprocess engineering University College DublinBelfieldDublin 4Ireland School of Biological Sciences Queen's University BelfastUniversity RoadBelfastBT71NNNorthern IrelandUK

The large quantity of marine methane hydrates has driven substantial interest in methane-gas-fuel potential,especially with the qualified success of Shensu(2017)and nankai-Trough(2014&17)production trials via depressurisation(blighted ultimately by sanding out),building on an earlier Malik-2008 trial for permafrost-bound *** particular,obviating deep-water-drilling approaches,such as the MeBO production rig(without such a drill bit),together with blowout preventers,constitutes a tantalising cost-saving *** means of addressing sand production by customised gravel packs,wellbore screens and slotted liners with from-seafloor drilling will be expected to lead to future production-trial ***,despite these exciting engineering advances and a few marinemimicking laboratory studies of methane-hydrate kinetics and stabilisation from microbial perspectives,relatively little is known about the thermogenic or microbial origin of marine hydrates,nor their possible formation kinetics or potential stabilisation by microbial sources as an exponent of Gaia's hypothesis,or within the context of“Gaia's breath”as regards global methane‘exhalations’.Here,for the first time,we elucidate the methylotrophic-microbial basis for kinetic enhancement and stabilisation of marine-hydrate formation in both deionised-and sea-water,identifying the key protein at play,which has some similarity to porins in other methylotrophic *** so doing,we suggest such phenomena in marine hydrates as evidence of Gaia's hypothesis.

关键词： Gas hydrate Microbes Methylotrophs

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 ***,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 *** are briefly reviewed before the latter approach is set *** partitions the rotation rate and strain rate tensors into normal/local and non-normal/non-local *** then study the relation between the VGT dynamics and ejection-sweep events in a channel flow *** 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 *** 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 *** 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

Deletion or underexpression of the Y-chromosome genes cDY2 and HSFY is associated with maturation arrest in American men with nonobstructive azoospermia

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Asian journal of Andrology 2012年第5期14卷 676-682页

作者： Peter j Stahl Anna n Mielnik christopher E Barbieri Peter n Schlegel Darius A Paduch Department of Urology Weill Cornell Medical CollegeNew York Presbyterian HospitaI-CornellNew YorkNY 10065USA

Maturation arrest （MA） refers to failure of germ cell development leading to clinical nonobstructive azoospermia. Although the azoospermic factor （AZF） region of the human Y chromosome is clearly implicated in some cases, thus far very little is known about which individual Y-chromosome genes are important for complete male germ cell development. We sought to identify single genes on the Y chromosome that may be implicated in the pathogenesis of nonobstructive azoospermia associated with MA in the American population. Genotype-phenotype analysis of 132 men with Y-chromosome microdeletions was performed. Protein-coding genes associated with MA were identified by visual analysis of a genotype-phenotype map. Genes associated with MA were selected as those genes within a segment of the Y chromosome that, when completely or partially deleted, were always associated with MA and absence of retrievable testicular sperm. Expression of each identified gene transcript was then measured with quantitative RT-PcR in testicular tissue from separate cohorts of patients with idiopathic MA and obstructive azoospermia. Ten candidate genes for association with MA were identified within an 8.4-Mb segment of the Y chromosome overlapping the AZFb region. cDY2and HSFYwere the only identified genes for which differences in expression were observed between the MA and obstructive azoospermia cohorts. Men with obstructive azoospermia had 12-fold higher relative expression of cDY2transcript （1.33__.0.40 vs. 0.11＋_0.04; P=O.O003） and 16-fold higher expression of HSFYtranscript （0.78__.0.32 vs. 0.05_0.02; P=O.O005） compared to men with MA. cDY2 and HSFYwere also underexpressed in patients with Sertoli cell only syndrome. These data indicate that cDY2and HSFYare located within a segment of the Y chromosome that is important for sperm maturation, and are underexpressed in testicular tissue derived from men with MA. These observations suggest that impairments in cDY2 or HSFYexpression could be impli

关键词： cDY1 protein cDY2 protein genetics histology HSFY human make infertility nonobstructive azoospermia spermato-genesis sperm maturation

Small bowel MRI enteroclysis or follow through:Which is optimal?

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World journal of Gastroenterology 2009年第42期15卷 5300-5306页

作者： Ian c Lawrance christopher j Welman Peter Shipman Kevin Murray School of Medicine and Pharmacology University of Western AustraliaFremantle HospitalWA 6160Australia centre for Inflammatory Bowel Disease Fremantle HospitalWA 6160Australia Department of Radiology Fremantle HospitalWA 6160Australia Statistical consulting Group School of Mathe-matics and StatisticsUniversity of Western AustraliaWA 6009Australia

AIM： TO determine if a nasojejunal tube （njT） is required for optimal examination of enteroclysis and if patients can be examined only in the supine position. METHODS： Data were collected from all patients undergoing small bowel （SB） magnetic resonance imaging （MRI） examination over a 32-mo period. Patients either underwent a magnetic resonance （MR） follow-through （MRFT） or a MR enteroclysis （MRE） in the supine position. The quality of proximal and distal SB distension as well as the presence of motion artefact and image quality were assessed by 2 radiologists. RESULTS： One hundred and fourteen MR studies were undertaken （MRFT-49, MRE-65） in 108 patients in the supine position only. Image artefact was more frequent in MRE than in MRFT （29.2% vs 18.4%）, but was not statistically significant （P = 0.30）. Adequate distension of the distal SB was obtained in 97.8% of MRFT examinations and in 95.4% of MRE examinations, respectively. Proximal SB distension was, however, less frequently optimal in MRFT than in MRE （P = 0.0036）, particularly in patients over the age of 50 years （P = 0.0099）. Image quality was good in all examinations. cOncLUSIOn： all patients could be successfully iraaged in the supine position. MRE and MRFT are equivalent for distal SB distension and artefact effects. Proximal SB distension is frequently less optimal in MRFT than in MRE. MRE is, therefore, the preferred MR examination method of the SB.

关键词： Magnetic resonance enteroclysis Magnetic resonance enterography Magnetic resonance follow through Artefact

Bank erosion in an Andean páramo river system: Implications for hydro-development and carbon dynamics in the neotropical Andes

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journal of Mountain Science 2019年第2期16卷 243-255页

作者： Derek j.MARTIn christopher ELY Beverley c.WEMPLE Department of Geography and Planning Appalachian State University Department of Geography University of Vermont

The páramo of the northern Andes provide critically important ecosystem services to the northern Andean region in the form of water provisioning and carbon sequestration, both of which are a result of the páramo?s organic-rich soils. Little is known, however, about the hydro-geomorphic characteristics of the rivers that drain these ecosystems. With impending plans for widespread hydro-development and increasing implementation of carbon-sequestering compensation for ecosystem services programs in the region it is imperative that we develop a thorough understanding of the hydrogeomorphic role that rivers play in this unique ecosystem. The objective of this study was to quantify bank erosion along an Amazonian headwater stream draining a small, relatively undisturbed páramo catchment to gain a better understanding of the natural erosion regime and the resulting sediment contributions from this unique ecosystem. This study implemented a combination of field, laboratory, and Geographic Information Systems techniques to quantify bank erosion rates and determine a bank erosion sediment yield from the ningar River, a small páramo catchment(22.7 km^2) located in the eastern Andean cordillera of Ecuador. Results show that bank erosion rates range from 3.0 to ≥ 390.0 mm/yr, are highly episodic, and yield at least 487 tons of sediment annually to the ningar River. These results imply that 1) páramo ecosystems substantially contribute to the sediment load of the Amazon River basin; 2) bank erosion is a potentially significant flux component of basin-scale carbon cycles in páramo ecosystems; and 3) hydrologic alteration campaigns(dam building) will likely critically alter these contributions and concomitantly disconnect a critical source of sediment and nutrients to downstream ecosystems.

关键词： Bank erosion Páramo Fluvial geomorphology Andes

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 *** support is targeted for tailgate applications, however, it can also be utilized for roof support in various types of mining *** 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 *** changes to each design aspect of the Propsetter was key to successfully improving the roof support's load capacity while maintaining controlled *** 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 *** 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 *** 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

On Systems of Boundary Value Problems for Differential Inclusions

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Acta Mathematica Sinica,english Series 2007年第3期23卷 549-556页

作者： Lynn ERBE christopher c.TISDELL Patricia j.Y.WOnG Department of Mathematics The University of Nebraska-LincolnLincolnNE 68588-0130USA School of Mathematics and Statistics The University of New South WalesSydney 2052Australia School of Electrical and Electronic engineering Nanyang Technological University50 Nanyan9 AvenueSingapore 639798Singapore

Herein we consider the existence of solutions to second-order, two-point boundary value problems （BVPs） for systems of ordinary differential inclusions. Some new Bernstein-nagumo conditions are presented that ensure a priori bounds on the derivative of solutions to the differential inclusion. These a priori bound results are then applied, in conjunction with appropriate topological methods, to prove some new existence theorems for solutions to systems of BVPs for differential inclusions. The new conditions allow of the treatment of systems of BVPs without growth restrictions.

关键词： boundary value problem, systems of differential inclusions, existence of solutions a priori bounds Bernstein-nagumo condition

Impact of exome sequencing in inflammatory bowel disease

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World journal of Gastroenterology 2013年第40期19卷 6721-6729页

作者： christopher j cardinale judith R Kelsen Robert n Baldassano Hakon Hakonarson center for Applied Genomics Children’s Hospital of PhiladelphiaAbramson Research Center Suite 1216PhiladelphiaPA 19104United States Division of Gastroenterology Hepatologyand NutritionDepartment of PediatricsChildren’s Hospital of PhiladelphiaPerelman School of Medicine at the University of PennsylvaniaPhiladelphiaPA 19104United States

Approaches to understanding the genetic contribution to inflammatory bowel disease(IBD)have continuously evolved from family-and population-based epidemiology,to linkage analysis,and most recently,to genome-wide association studies(GWAS).The next stage in this evolution seems to be the sequencing of the exome,that is,the regions of the human genome which encode *** GWAS approach has been very fruitful in identifying at least 163 loci as being associated with IBD,and now,exome sequencing promises to take our genetic understanding to the next *** this review we will discuss the possible contributions that can be made by an exome sequencing approach both at the individual patient level to aid with disease diagnosis and future therapies,as well as in advancing knowledge of the pathogenesis of IBD.

关键词： Sequencing Exome Genetics Inflammatory bowel disease