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Lipopolysaccharide inhibits or accelerates biomedical titanium corrosion depending on environmental acidity

International journal of Oral Science 2015年第3期7卷 179-186页

作者： Fei Yu Owen Addison stephen j baker Alison j Davenport School of Metallurgy and Materials University of Birmingham Biomaterials Unit College of Medical and Dental Sciences University of Birmingham School of Geography Earth and Environmental Sciences University of Birmingham

Titanium and its alloys are routinely used as biomedical implants and are usually considered to be corrosion resistant under physiological conditions. However, during inflammation, chemical modifications of the peri-implant environment including acidification occur. In addition certain biomolecules including lipopolysaccharide（LPS）, a component of Gram-negative bacterial cell walls and driver of inflammation have been shown to interact strongly with Ti and modify its corrosion resistance. Gram-negative microbes are abundant in biofilms which form on dental implants. The objective was to investigate the influence of LPS on the corrosion properties of relevant biomedical Ti substrates as a function of environmental acidity. Inductively coupled plasma mass spectrometry was used to quantify Ti dissolution following immersion testing in physiological saline for three common biomedical grades of Ti（ASTM Grade 2, Grade 4 and Grade 5）. Complementary electrochemical tests including anodic and cathodic polarisation experiments and potentiostatic measurements were also conducted. All three Ti alloys were observed to behave similarly and ion release was sensitive to p H of the immersion solution. However, LPS significantly inhibited Ti release under the most acidic conditions（p H 2）, which may develop in localized corrosion sites, but promoted dissolution at p H 4–7, which would be more commonly encountered *** observed pattern of sensitivity to environmental acidity of the effect of LPS on Ti corrosion has not previously been reported. LPS is found extensively on the surfaces of skin and mucosal penetrating Ti implants and the findings are therefore relevant when considering the chemical stability of Ti implant surfaces in vivo.

关键词： corrosion electrochemistry inductively coupled plasma mass spectrometry lipopolysaccharide titanium

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Depression, anxiety, and cardiac morbidity outcomes after coronary artery bypass surgery： a contemporary and practical review

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journal of Geriatric Cardiology 2012年第2期9卷 197-208页

作者： Phillip j Tully Robert A baker Department of Surgery Flinders Medical Centre and Flinders University of South Australia 3 Flinders Drive Bedford Park SA 5042 Australia School of Psychology University of Adelaide Hughes Building North Terrace Adelaide SA 5005 Australia Discipline of Psychiatry The University of Adelaide Eleanor Harold Building Frome Road Adelaide SA 5005 Australia Heart Failure Self Management Program Ambulatory and Primary Healthcare Directorate Hampstead Rehabilitation Centre 207 Hampstead Road Northfield SA 5085 Australia

Research to date indicates that the number of coronary artery bypass graft （CABG） surgery patients affected by depression （i.e., major, minor, dysthymia） approximates between 30% and 40% of all cases. A longstanding empirical interest on psychosocial factors in CABG surgery patients highlights an association with increased risk of morbidity in the short and longer term. Recent evidence suggests that both depression and anxiety increase the risk for mortality and morbidity after CABG surgery independent of medical factors, although the behavioral and biological mechanisms are poorly understood. Though neither depression nor anxiety seem to markedly affect neuropsy- chological dysfunction, depression confers a risk for incident delirium. Following a comprehensive overview of recent literature, practical advice is described for clinicians taking into consideration possible screening aids to improve recognition of anxiety and depression among CABG surgery patients. An overview of contemporary interventions and randomized, controlled trials are described, along with suggestions for future CABG surgery research.

关键词： Depression Depressive disorder Coronary artery bypass Coronary artery disease Antidepressive agents Anxiety

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p53:a tumor suppressor hiding in plain sight

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journal of Molecular Cell Biology 2019年第7期11卷 536-538页

作者： Suzanne j.baker Bert Vogelstein St jude Children's Research Hospital Department of Developmental Neurobiology262 Danny Thomas PlaceMemphisTN 38105USA Ludwig Center Howard Hughes Medical Institute Johns Hopkins Kimmel Cancer Center1650 Orleans Street StBaltimoreMD 21205USA

It is a pleasure to join the other authors in this issue to hon orDr Arnold Levi neand the remarkable impact of his *** paths crossed with Amie's when our genetic analyses of colorectal cancers led us to investigate the p53 gene and identify it as a tumor suppressor gene.p53 was initially identified by Arnie and others as an oncogene and tumor antigen,nearly a decade before its role as a tumor suppressor gene was *** fondly remember Arnie visiting our lab,and we visiting his,to discuss the implications of the genetic alterations our group identified in human cancers and how we could work together to investigate the voluminous new questions these mutations raised.

关键词： pleasure Arnold raised

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Subtypes of functional dyspepsia

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World journal of Gastroenterology 2006年第17期12卷 2667-2671页

作者： Georgina baker Robert j Fraser Graeme Young Department of Gastroenterology Repatriation General Hospital and Flinders Medical Centre Australia

Functional dyspepsia is a common clinical condition characterised by chronic or recurrent upper abdominal pain or discomfort commonly associated with a variety of associated gastrointestinal symptoms and a normal endoscopy. To standardise research-based approaches, an initial categorisation of into sub groups was agreed to, based on clusters of symptoms. However the early expectation that these subgroups would be associated with distinct pathophysiologies amenable to specific therapy has not been realised. A classification based on the most troublesome symptom has been suggested but the utility of this is also unclear. More recent data suggest that some of the pathophysiologic dysfunctions may be associated with specific symptoms and so provide a better tool for grouping patients. But this approach remains incomplete as current insights into the pathogenesis are still too limited for this to be satisfactory. In conclusion, no classification provides for an adequate treatment-based approach to the syndrome of functional dyspepsia. As a consequence treatment remains largely empiric.

关键词： Functional dyspepsia Classification Subtypes Symptoms Pathophysiology Management

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Surface Characterisation of Silicon Based MEMS

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Chemical Research in Chinese Universities 2004年第4期20卷 407-410页

作者： LI j. CUI Z M. A. baker The Surface Analysis Laboratory School of Engineering University of SurreyRutherford Appleton LaboratoryThe Surface Analysis Laboratory School of Engineering University of Surrey Guildford GU2 7XH UKChilton Didcot UKGuildford GU2 7XH UK

Polysilicon Microelectromechanical systems(MEMS) are the subject of intensive researches. Surface chemistry and topography of a MEMS test structure fabricated at Sandia National Laboratory, USA, were studied by means of scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS) and atomic force microscopy(AFM). XPS C_ 1sand Si_ 2pspectra from the polysilicon components, silicon nitride substrate and a reference silicon wafer were compared. The results confirm the presence of a self-assembled monolayer(SAM) on the MEMS surface. An island-like morphology was found on both polysilicon and silicon nitride surfaces of the MEMS. The islands take the form of caps, being up to 0.5 μm in diameter and 20 nm in height. It is concluded that the co-existence of columnar growth and equiaxed growth during the low pressure chemical vapor deposition(LPCVD) of these layers leads to the observed morphology and the islands are caps to the columnar structures.

关键词： Microelectromechanical systems XPS Atomic force microscopy

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Are sperm capacitation and apoptosis the opposite ends of a continuum driven by oxidative stress？

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Asian journal of Andrology 2015年第4期17卷 633-639页

作者： Robert j Aitken Mark A baker Brett Nixon Priority Research Centre in Reproductive Science Discipline of Biological Sciences and Hunter Medical Research Institute University of Newcastle NSW 2308 Australia.

This chapter explores the possibility that capacitation and apoptosis are linked processes joined by their common dependence on the continued generation of reactive oxygen species （ROS）. According to this model capacitation is initiated in spematozoa following their release into the female reproductive tract as a consequence of intracellular ROS generation, which stimulates intracellular cAMP generation, inhibits tyrosine phosphatase activity and enhances the formation of oxysterols prior to their removal from the sperm surface by albumin. The continued generation of ROS by capacitating populations of spermatozoa eventually overwhelms the limited capacity of these cells to protect themselves from oxidative stress. As a result the over-capacitation of spermatozoa leads to a state of senescence and the activation of a truncated intrinsic apoptotic cascade characterized by enhanced mitochondrial RO$ generation, lipid peroxidation, motility loss, caspase activation and phosphatidylserine externalization. The latter may be particularly important in instructing phagocytic leukocytes that the removal of senescent, moribund spermatozoa should be a silent process unaccompanied by the generation of proinflammatory cytokines. These observations reveal the central role played by redox chemistry in defining the life and death of spermatozoa. A knowledge of these mechanisms may help us to engineer novel solutions to both support and preserve the functionality of these highly specialized cells.

关键词： apoptosis reactive oxygen species sperm capacitation

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The importance of depression and alcohol use in coronary artery bypass graft surgery patients：risk factors for delirium and poorer quality of life

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journal of Geriatric Cardiology 2016年第1期13卷 51-57页

作者： joanne M Humphreys Linley A Denson Robert A baker Phillip j Tully School of Psychology Faculty of Health Sciences University of Adelaide Australia Cardiac Surgery Research Department of Surgery School of Medicine Flinders University of South Australia Australia University of Bordeaux Department of Neuroepidemiology Bordeaux France INSERM Department of Neuroepidemiology Bordeaux France Freemasons Foundation Centre for Men's Health Discipline of Medicine School of Medicine University of Adelaide Australia

ObjectiveToinvestigate whether depression, anxiety and stress increase the risk for delirium and poor quality of life （QOL） after co-ronary artery bypass （CABG） *** total of 180 CABG patients （mean age of 63.5 ± 10.1 years, 82.2% males） completed baseline and postoperative self-report questionnaires to assess distress and QOL. Incident delirium was diagnosed postoperatively with a structured clinical interview and patients were monitored every day post-operatively for confusion and disturbance in *** Delirium developed in 63 persons （35% of sample）. After adjustment for covariates, delirium was significantly associated with depression [odds ratio （OR）： 1.08; 95% confidence interval （CI）： 1.03-1.13,P = 0.003], anxiety （OR： 1.07; 95% CI： 1.02-1.13,P= 0.01） and stress （OR： 1.05; 95% CI： 1.00-1.09,P= 0.03）. Preoperative depression scores were associated with poorer QOL including bodily pain （β =-0.39,P = 0.013）, vitality （β=-0.32,P = 0.020）, social functioning （β=-0.51,P≤0.001）, emotional role function （β=-0.44,P = 0.003） and general health （β=-0.33,P = 0.038）. Among the covariates, harmful levels of alcohol use was consistently associated with poorer *** Depression and harmful levels of alcohol use were consistently associated with poorer QOL whereas depression, anxiety and stress were associated with delirium risk. These findings point to further research examining depression and harmful levels of alcohol use in coronary heart disease populations undergoing coronary revascularization.

关键词： Coronary artery bypass grafts Coronary heart disease Delirium Depression Quality of life

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The role of phosphorus in the metabolism of arsenate by a freshwater green alga, Chlorella vulgaris

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journal of Environmental Sciences 2016年第11期28卷 169-178页

作者： josh baker Dirk Wallschlager Trent University Environmental and Life Sciences Graduate Program 1600 West Bank Dr Peterborough ON K9L 0G2 Canada School of the Environment Department of Chemistry and Water Quality Centre Trent University 1600 West Bank Dr Peterborough ONK9L 0G2 Canada

A freshwater microalga, Chlorella vulgaris, was grown in the presence of varying phosphate concentrations（〈 10–500 μg/L P） and environmentally realistic concentrations of arsenate（As（Ⅴ））（5–50 μg/L As）. Arsenic speciation in the culture medium and total cellular arsenic were measured using AEC-ICP-MS and ICP-DRC-MS, respectively, to determine arsenic biotransformation and uptake in the various phosphorus scenarios. At high phosphate concentration in the culture medium, 〉 100 μg/L P, the uptake and biotransformation of As（Ⅴ） was minimal and dimethylarsonate（DMAs（Ⅴ）） was the dominant metabolite excreted by C. vulgaris, albeit at relatively low concentrations. At common environmental P concentrations, 0–50 μg/L P, the uptake and biotransformation of As（Ⅴ） increased. At these higher As-uptake levels, arsenite（As（Ⅲ）） was the predominant metabolite excreted from the cell. The concentrations of As（Ⅲ） in these low P conditions were much higher than the concentrations of methylated arsenicals observed at the various P concentrations studied. The switchover threshold between the（small） methylation and（large） reduction of As（Ⅴ） occurred around a cellular As concentration of 1 fg/cell. The observed nearly quantitative conversion of As（Ⅴ） to As（Ⅲ） under low phosphate conditions indicates the importance of As（Ⅴ） bio-reduction at common freshwater P concentrations. These findings on the influence of phosphorus on arsenic uptake, accumulation and excretion are discussed in relation to previously published research. The impact that the two scenarios of As（Ⅴ） metabolism, As（Ⅲ） excretion at high As（Ⅴ）-uptake and methylarsenical excretion at low As（Ⅴ）-uptake, have on freshwater arsenic speciation is discussed.

关键词： Arsenic Speciation Phosphorus Freshwater algae Toxicity Biotransformation

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Interstitial strengthening in *** and alloys

Advanced Powder Materials

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Advanced Powder Materials 2022年第4期1卷 1-7页

作者： Ian baker Thayer SchoolofEngineering DartmouthCollegeHanoverNH03755USA

In this short review,we highlight instances where interstitials have been shown to substantially increase the yield strength and work-hardening rate(WHR)of ***,particularly high entropy alloys,medium entropy alloys,TWIP steels and stainless ***,the common practice of describing interstitial strengthening in *** using models that are used to explain substitutional strengthening appears to be neither appropriate nor *** we suggest,based on the literature,that the yield strength increase due to interstitials in *** is more appropriately described by a linear dependence on the concentration:due to a paucity of experimental studies,the dependence of the yield strength and WHR on misfit parameters is currently ***,the source of the strengthening remains unclear.A feature that has been observed in several *** is that interstitial additions lead to a change from wavy to planar slip although the origin of this change,which may be related to changes in stacking fault energy as well as other factors,remains *** paper concludes by outlining areas of future research,including the need to develop a new model for interstitial strengthening in ***.

关键词： Interstitials f.c.c.alloys High entropy alloys Yield strength Work-hardening rate

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Drug Repurposing for the Treatment of Mycobacterium abscessus Infections

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Infectious Microbes & Diseases 2023年第3期5卷 101-110页

作者： Emily j.baker Antonia Molloy jonathan A.G.Cox School of Life and Health Sciences Aston UniversityAston TriangleBirminghamUK.

With the ever-increasing burden of antimicrobial resistance,the demand to introduce countermeasures becomes increasingly *** urgency of this need is intensified by the void in antibiotic discovery,with the identification of novel compounds declining with *** increasing concern is Mycobacterium abscessus,which displays high levels of intrinsic resistance that lead to poor success rates,even after lengthy drug *** tackling these issues is now focused on the repurposing of preexisting drugs for antimycobacterial use,facilitating the discovery of antimicrobial compounds amidst a crisis where novel antibiotics are *** of this includes the use of combination treatments,whereby coadministration of synergistic compounds can reduce dose requirements and slow the progression of antimicrobial resistance in the long *** this review,we will introduce the current therapeutic options for *** and provide insight into why treatment is so *** will also compile the current updates within drug repurposing for this pathogen,including the use of unconventional agents such as antimalarial drugs,the repositioning of antitubercu-losis candidates and the repurposing of preexisting antibiotics,including the application of combination *** addition,the in vitro drug screening platforms used in their discovery will be appraised,with the view of highlighting potential future perspectives that may help increase physiological *** review provides a timely appraisal of the future of *** treatment.

关键词： drug repurposing Mycobacterium abscessus antimycobacterial drug discovery antimicrobials

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