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An Efficient,Energy Stable Scheme for the Cahn-Hilliard-Brinkman System

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Communications in Computational Physics 2013年第4期13卷 929-957页

作者： craig Collins Jie Shen Steven M.Wise Department of Mathematics University of TennesseeKnoxvilleTN 37912USA Department of Mathematics Purdue UniversityWest LafayetteIN 47907USA

We present an unconditionally energy stable and uniquely solvable finite difference scheme for the Cahn-Hilliard-Brinkman(CHB)system,which is comprised of a Cahn-Hilliard-type diffusion equation and a generalized Brinkman equation modeling fluid *** CHB system is a generalization of the Cahn-Hilliard-Stokes model and describes two phase very viscous flows in porous *** scheme is based on a convex splitting of the discrete CH energy and is *** equations at the implicit time level are nonlinear,but we prove that they represent the gradient of a strictly convex functional and are therefore uniquely solvable,regardless of time step *** to energy stability,we show that the scheme is stable in the time and space discrete ℓ^(∞)(0,T;H_(h)^(1))and ℓ^(2)(0,T;H_(h)^(2))*** also present an efficient,practical nonlinear multigrid method–comprised of a standard FAS method for the Cahn-Hilliard part,and a method based on the Vanka smoothing strategy for the Brinkman part-for solving these *** particular,we provide evidence that the solver has nearly optimal complexity in typical *** solver is applied to simulate spinodal decomposition of a viscous fluid in a porous medium,as well as to the more general problems of buoyancy-and boundary-driven flows.

关键词： Cahn-Hilliard equation Stokes equations Brinkman equation finite difference methods nonlinear multigrid convex splitting energy stability

Combined aqueous misdirection and persistent choroidal effusions following implantation of a Preserflo Micro Shunt

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International Journal of Ophthalmology(English edition) 2023年第4期16卷 652-655页

作者： Huzaifa Malick craig Wilde Richard E Stead University Hospitals of Leicester Leicester Royal InfirmaryInfirmary SquareLeicesterLE15WW***United Kingdom Queens Medical Centre Derby RoadNottingham NG72UHUnited Kingdom

AIM:To describe a case of aqueous misdirection complicated by subsequent persistent choroidal effusions following implantation of a Preserflo Micro Shunt(PMS)device to treat advanced closed angle ***:A 67-year-old caucasian female with advanced primar y angle-closure glaucoma on four medications with an intraocular pressure(IOP)of 26 mm Hg was listed for a PMS insertion with mitomycin C(MMC).RESULTS:Past ocular history was significant for pseudophakia and previous yttrium aluminum garnet(YAG)peripheral *** was uneventful but on the first postoperative day,she developed aqueous misdirection complicated by subsequent development of persistent uveal *** treatment strategies including atropine drops,YAG hyaloidotomy and choroidal effusion drainage proved ineffective.A combination of oral steroids and pars plana vitrectomy(PPV)along with an irido-zonulohyloidectomy(IZH)proved ***:To the best of the author’s knowledge,this is the first published case of aqueous misdirection complicated with the presence of significant,unresolving choroidal effusions,highlighting the possibility and sequelae of comorbid pathology in nanophthalmic eyes.

关键词： combined aqueous misdirections persistent choroidal effusions

Correcting for spatially dependent intrinsic efficiency on a germanium double-sided strip detector to improve nuclear forensics response

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Radiation Detection Technology and Methods 2022年第1期6卷 78-87页

作者： Timothy Jacomb-Hood James Fast craig Department of Nuclear Engineering Texas A&M UniversityCollege StationTXUSA Pacific Northwest National Laboratory RichlandWAUSA

Purpose The Germanium Gamma-ray Imager(GeGI)is a planar high-purity germanium(HPGe)imaging detector developed by PHDS Co for far-field *** research investigates the detector’s ability for measuring heterogeneous sources in the near field,placed directly on the detector’s faceplate,to perform isotopic mapping for nuclear forensic *** The intrinsic efficiency is strongly dependent on where the photons interact within the *** efficiency varies by up to 20%within the sensitive volume of the *** efficiency was mapped using eight different photons from 123 to 1274 keV emitted from a collimated 154Eu *** were measured at 108 locations to interpolate the efficiency at any point on the detector’s *** The position and energy dependence are uncorrelated,and thus,the absolute efficiency at any position and for any gamma-ray energy can be calculated by the convolution of the spatial and energy *** The results on this research show that detection efficiency for a planar two-sided strip HPGe is spatially dependent and shows typical energy *** spatial dependence,which does not have any additional energy dependence,can be corrected.A 154Eu source was used in this research and was able to spatially calibrate for photon energies ranging from 100 to 1300 *** method is applicable for sources with higher gamma *** advantages of the method demonstrated that after initial in-laboratory calibration,a single measurement in the field can be used to efficiently calibrate the HPGe as a function of photon interaction on the crystal.

关键词： Nuclear forensics Radiation detection Gamma-ray imaging

Ground characterization and roof mapping: Online sensor signal-based change detection

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International Journal of Mining Science and Technology 2015年第6期25卷 905-913页

作者： Bahrampour Soheil Rostami Jamal Ray Asok Naeimipour Ali Collins craig Electrical Engineering Department The Pennsylvania State University Department of Energy and Mineral Engineering The Pennsylvania State University J. H. Fletcher & Co.TM

Measurement while drilling systems are becoming an important part of excavation operations for rock characterization and ground support design that require reliable information on rock strength and location ＆ frequency of joints or voids. This paper focuses on improving rock characterization algorithms for instrumented roof-boRer systems. For this purpose, an improved void detection algorithm is proposed, where the underlying theory is built upon the concept of mean change detection based on the feed pressure signals. In addition, the application of acoustic sensing for void detection is examined and it is shown that the variance of the filtered acoustic signal is correlated to the strength of the material being drilled. The proposed algorithm has been validated on the data collected from full-scale drilling tests in various concrete and rock samples at the J. H. Fletcher facility.

关键词： Measurement while drilling systemsRoof mappingVoid detectionOnline change detection

Correlation of MRI-determined small bowel Crohn’s disease categories with medical response and surgical pathology

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World Journal of Gastroenterology 2009年第27期15卷 3367-3375页

作者： Ian craig Lawrance Christopher J Welman Peter Shipman Kevin Murray School of Medicine and Pharmacology University of Western AustraliaFremantle Hospital WA 6160 Australia Department of Gastroenterology Fremantle Hospital WA 6160 Australia Department of Radiology Fremantle Hospital WA 6160 Australia Statistical Consulting Group School of Mathematics and Statistics University of Western AustraliaWA 6160 Australia

AIM: To determine whether magnetic resonance imaging (MRI) can be used to categorize small bowel Crohn's disease (SB CD) into groups that correlate with response to medical therapy and surgical ***: Data was collected from all patients with MRI evidence of SB CD without significant colonic disease over a 32-mo period. Two radiologists, blinded to clinical findings, evaluated each MRI and grouped them based on bowel wall thickness and wall enhancement. These categories were: (1) "fibrosis", (2) "mild segmental hyper-enhancement and mild wall thickening", (3) "mild segmental hyper-enhancement and marked wall thickening", (4) "marked segmental transmural hyper-enhancement". Patient response to additional medical therapy post-MRI was prospectively determined at 8-wk. Non-responders underwent endoscopy and were offered therapeutic endoscopy or surgery. Surgical pathology was assessed against the MRI category. RESULTS: Fifty-five patients were included. Females and category "2" patients were more likely, and patients with luminal narrowing and hold-up less likely, to respond to medical therapy (P hat SB CD can be grouped by the MRI f indings and that these groups are associated with patients more likely to respond to continued medical therapy. The MRI categories also correlated with the presence and level of intestinal inflammation and fibrosis on surgical pathology, and may be of prognostic use in the management of CD patients.

关键词： Magnetic resonance imaging Crohn's disease Fibrosis Prognosis Pathology

Age and sex differences in niche use at molt and its effect on plumage coloration characteristics in a bird

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Current Zoology 2019年第3期65卷 251-260页

作者： Emilio PAGANI-NUNEZ craig R.A.BARNETT Juan Carlos SENAR State Key Laboratory of Biocontrol Department of Ecology/School of Life Sciences Sun Yat-sen University Guangzhou China Department of Zoology Graduate School of Science University of Kyoto Kitashirakawaoiwake-cho Sakio-ku Kyoto Japan Natural History Museum of Barcelona Barcelona Spain

Bird plumage is often very colorful and can communicate the quality of the bearer to conspecifics. These plumage-based signals of quality are composed of multiple pigments (e.g., melanin and carote no ids). Therefore, sex and age classes, which often show marked differe nces in plumage coloration, may have different dietary needs for the different plumage components and this might promote pref ere nces for differe nt dietary niches at different molting stages. However, no study has addressed the role that changes in niche use play in the expression of multiple component plumage signals in birds. We used stable isotope analysis to test the hypothesis that niche use is related to age and sex and to differently cultured plumage patches, yellow carotenoid-based and black melanin-based, in great tits Parus major. We recorded high niche overlap between plumage patches, although δ15N was higher in black than yellow plumage. Niche overlap was relatively low for age classes and relatively high for sex classes, and age classes showed a contrasting pattern of niche overlap between carotenoid- and melanin-based plumages. Moreover,δ13C, but not δ15N, had a significant negative relationship with carotenoid-based plumage, which was only apparent in juveniles. Take n together, our results demonstrate that n iche use had a moderate in fluence on plumage coloration characteristics of great tit individuals, mostly associated with δ13C rather than with δ15N and with age rather than with sex. Therefore, our study is significant because it confirms the releva nee of n iche use duri ng orn ame nt production in free-livi ng birds.

关键词： carotenoids great tits melanin multiple ornaments niche overlap stable isotopes

Molecular regulation of telomerase activity in aging

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Protein & Cell 2011年第9期2卷 726-738页

作者： craig Nicholls He Li Jian-Qiu Wang Jun-Ping Liu Molecular Signalling Laboratory Murdoch Childrens Research InstituteFlemington RoadParkvilleVictoria 3052Australia Institute of Aging Research Hangzhou Normal University School of MedicineHangzhou 310036China Department of Immunology Monash UniversityMelbourneVictoria 3004Australia Department of Genetics University of MelbourneVictoria 3052Australia

The process of aging is mitigated by the maintenance and repair of chromosome ends(telomeres),resulting in extended *** review examines the molecular mechanisms underlying the actions and regulation of the enzyme telomerase reverse transcriptase(TERT),which functions as the primary mechanism of telomere maintenance and regulates cellular life *** increased cell proliferation,telomerase is also a key factor in facilitating cancer cell *** review focuses on aspects of hormonal regulations of telomerase,and the intracellular pathways that converge to regulate telomerase activity with an emphasis on molecular interactions at protein and gene *** addition,the basic structure and function of two key telomerase enzyme components—the catalytic subunit TERTand the template RNA(TERC)are discussed briefly.

关键词： telomerase aging telomerase reverse transcriptase(TERT)

Formation and speciation of disinfection byproducts during chlor(am)ination of aquarium seawater

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Journal of Environmental Sciences 2015年第7期27卷 116-124页

作者： haiting Zhang Huiyu Dong craig Adams Zhimin Qiang Gang Luan Lei Wang Key Laboratory of Drinking Water Science and Technology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Department of Civil and Environmental Engineering Utah State University Water Quality Analysis and Control Center Department of Life Support Equipments for Aquatic AnimalsBeijing Aquarium

The chemistry associated with the disinfection of aquarium seawater is more complicated than that of freshwater, therefore limited information is available on the formation and speciation of disinfection byproducts（DBPs） in marine aquaria. In this study, the effects of organic precursors, bromide（Br-） and pre-ozonation on the formation and speciation of several typical classes of DBPs, including trihalomethanes（THM4）, haloacetic acids（haAs）,iodinated trihalomethanes（I-THMs）, and haloacetamides（hac Ams）, were investigated during the chlorination/chloramination of aquarium seawater. Results indicate that with an increase in dissolved organic carbon concentration from 4.5 to 9.4 mg/L, the concentrations of THM4 and haAs increased by 3.2-7.8 times under chlorination and by 1.1-2.3 times under chloramination. An increase in Br-concentration from 3 to 68 mg/L generally enhanced the formation of THM4, I-THMs and hac Ams and increased the bromine substitution factors of all studied DBPs as well, whereas it impacted insignificantly on the yield of haAs. Pre-ozonation with 1 mg/L O3 dose substantially reduced the formation of all studied DBPs in the subsequent chlorination and I-THMs in the subsequent chloramination. Because chloramination produces much lower amounts of DBPs than chlorination, it tends to be more suitable for disinfection of aquarium seawater.

关键词： Disinfection byproducts Chlorination Chloramination Pre-ozonation Bromine substitution factorAquarium seawater

Community analysis of ammonia-oxidizing bacteria in activated sludge of eight wastewater treatment systems

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Journal of Environmental Sciences 2010年第4期22卷 627-634页

作者： Xiaohui Wang Xianghua Wen craig Criddle George Wells Jie Zhang Yin Zhao Department of Environmental Science and Engineering Tsinghua University Beijing 100084 China. Department of Civil and Environmental Engineering Jerry Yang & Akiko Yamazaki Environment & Energy Building Stanford University Stanford CA94305-4020 USA Beijing Drainage Group Co. Ltd. Beijing 100084 China

We investigated the communities of ammonia-oxidizing bacteria （AOB） in activated sludge collected from eight wastewater treatment systems using polymerase chain reaction （PCR） followed by terminal restriction fragment length polymorphism （T-RFLP）, cloning, and sequencing of the α-subunit of the ammonia monooxygenase gene （amoA）. The T-RFLP fingerprint analyses showed that different wastewater treatment systems harbored distinct AOB communities. However, there was no remarkable difference among the AOB T- RFLP profiles from different parts of the same system. The T-RFLP fingerprints showed that a full-scale wastewater treatment plant （WWTP） contained a larger number of dominant AOB species than a pilot-scale reactor. The source of influent affected the AOB community, and the WWTPs treating domestic wastewater contained a higher AOB diversity than those receiving mixed domestic and industrial wastewater. However, the AOB community structure was little affected by the treatment process in this study. Phylogenetic analysis of the cloned amoA genes clearly indicated that all the dominant AOB in the systems was closely related to Nitrosomonas spp. not to Nitrosospira spp. Members of the Nitrosomonas oligotropha and Nitrosomonas communis clusters were found in all samples, while members of Nitrosomonas europaea cluster occurred in some systems.

关键词： activated sludge ammonia-oxidizing bacteria T-RFLP amoA gene wastewater treatment plant