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Camouflage Patterning in Maize Leaves Results from a Defect in Porphobilinogen Deaminase

Molecular Plant 2009年第4期2卷 773-789页

作者： Mingshu Huanga Thomas L. Slewinski R. Frank baker , Diane Janick-Buckner Brent Buckner Gurmukh S. Johal david M. Braun Department of Biology Pennsylvania State University University Park PA 16802 Division of Science Truman State University Kirksville MO 63501 Department of Botany and Plant Pathology Purdue University West Lafayette IN 47907

Maize leaves are produced from polarized cell divisions that result in clonal cell lineages arrayed along the long axis of the leaf. We utilized this stereotypical division pattern to identify a collection of mutants that form chloroplast pigmentation sectors that violate the clonal cell lineages. Here, we describe the camouflage1 （cfl） mutant, which develops nonclonal, yellow-green sectors in its leaves. We cloned the cfl gene by transposon tagging and determined that it encodes porphobilinogen deaminase （PBGD）, an enzyme that functions early in chlorophyll and heme biosynthesis. While PBGD has been characterized biochemically, no viable mutations in this gene have been reported in plants. To investigate the in vivo function of PBGD, we characterized the cfl mutant. Histological analyses revealed that cfl yellow sectors display the novel phenotype of bundle sheath cell-specific death. Light-shift experiments determined that constant light suppressed cfl sector formation, a dark/light transition is required to induce yellow sectors, and that sectors form only during a limited time of leaf development. Biochemical experiments determined that of 1 mutant leaves have decreased PBGD activity and increased levels of the enzyme substrate in both green and yellow regions. Furthermore, the cfl yellow regions displayed a reduction in catalase activity. A threshold model is hypothesized to explain the cfl variegation and incorporates photosynthetic cell differentiation, reactive oxygen species scavenging, and PBGD function.

关键词： camouflage1 maize porphobilinogen deaminase tetrapyrrole biosynthesis variegated leaf.

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Predictive Ability of Hypertriglyceridemic Waist,Hypertriglyceridemic Waist-to-Height Ratio,and Waist-to-Hip Ratio for Cardiometabolic Risk Factors Clustering Screening among Chinese Children and Adolescents

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Biomedical and Environmental Sciences 2024年第3期37卷 233-241页

作者： XIAO Tian Li YUAN Shu Qian GAO Jing Yu Julien Sbaker YANG Yi De WANG Xi Jie ZHENG Chan Juan DONG Yan Hui ZOU Zhi Yong Key Laboratory of Molecular Epidemiology of Hunan Province School of MedicineHunan Normal UniversityChangsha 410081HunanChina The Institute of Interdisciplinary Studies Hunan Normal UniversityChangsha 410013HunanChina Chenzhou First People's Hospital Chenzhou 423000HunanChina Centre for Health and Exercise Science Research Hong Kong Baptist UniversityKowloon TongHong Kong 999077China Department of Sport Physical Education and HealthHong Kong Baptist UniversityKowloon TongHong Kong 999077China Vanke School of Public Health Tsinghua UniversityBeijing 100084China Institute of Child and Adolescent Health School of Public HealthPeking University Health Science CenterBeijing 100191China

Objective Hypertriglyceridemic waist(HW),hypertriglyceridemic waist-to-height ratio(HWHtR),and waist-to-hip ratio(WHR)have been shown to be indicators of cardiometabolic risk ***,it is not clear which indicator is more suitable for children and *** aimed to investigate the relationship between HW,HWHtR,WHR,and cardiovascular risk factors clustering to determine the best screening tools for cardiometabolic risk in children and *** This was a national cross-sectional *** and biochemical variables were assessed in approximately 70,000 participants aged 6–18 years from seven provinces in ***,physical activity,dietary intake,and family history of chronic diseases were obtained through ***,χ2 and logistic regression analysis was *** A significant sex difference was observed for HWHtR and WHR,but not for HW *** risk of cardiometabolic health risk factor clustering with HW phenotype or the HWHtR phenotype was significantly higher than that with the non-HW or non-HWHtR phenotypes among children and adolescents(HW:OR=12.22,95%CI:9.54-15.67;HWHtR:OR=9.70,95%CI:6.93-13.58).Compared with the HW and HWHtR phenotypes,the association between risk of cardiometabolic health risk factors(CHRF)clustering and high WHR was much weaker and not significant(WHR:OR=1.14,95%CI:0.97-1.34).Conclusion Compared with HWHtR and WHR,the HW phenotype is a more convenient indicator with higher applicability to screen children and adolescents for cardiovascular risk factors.

关键词： Hypertriglyceridemic waist Waist-to-hip ratio Children and adolescents China Hypertriglyceridemic waist-to-height ratio Cardiovascular risk factors

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Streaming Multimedia over Wireless Mesh Networks

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International Journal of Communications, Network and System Sciences 2008年第2期1卷 177-186页

作者： david Q. LIU Jason baker Indiana University – Purdue University Fort Wayne

Wireless mesh network (WMN) research is an emerging field in network communications. However, WMNs pose several difficulties in the transmission of information, especially time critical applications such as streaming video and audio. In this paper, we provide an overview of several research papers which utilize mesh networks for streaming multimedia. We compare the results of the research and the significance they bring to the field of wireless mesh networks. We then provide possible directions for future research into wireless mesh networks as they apply to streaming multimedia.

关键词： Wireless Mesh Networks Multimedia Video Quality

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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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Outpatient insulin use in type 2 diabetes mellitus and acute respiratory distress syndrome outcomes:A retrospective cohort study

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World Journal of Clinical Cases 2024年第17期12卷 2966-2975页

作者： Georges Khattar Samer Asmar Laurence Aoun Fares Saliba Shaza Almardini Saif Abu baker Catherine Hong Carolla El Chamieh Fadi Haddadin Toni Habib Omar Mourad Zeina Morcos Fatema Arafa Jonathan Mina Khalil El Gharib Mohammad Aldalahmeh Salman Khan Elie Bou Sanayeh Department of Medicine Holy Spirit University of KaslikJounieh 00000Lebanon Department of Internal Medicine Staten Island University HospitalStaten IslandNY 10305United States Public Heath and Biostatistics Independent ResearchBeirut 0000Lebanon Department of Medicine Lebanese UniversityBeirut 00000Lebanon Department of Medicine University of BalamandBeirut 00000Lebanon Department of Medicine Lebanese American UniversityBeirut 00000Lebanon Department of Medicine Northwell Health Staten Island University HospitalNew YorkNY 10305United States

BACKGROUND The impact of type 2 diabetes mellitus(T2DM)on acute respiratory distress syndrome(ARDS)is debatable.T2DM was suspected to reduce the risk and complications of ***,during coronavirus disease 2019(COVID-19),T2DM predisposed patients to ARDS,especially those who were on insulin at *** evaluate the impact of outpatient insulin use in T2DM patients on non-COVID-19 ARDS *** We conducted a retrospective cohort analysis using the Nationwide Inpatient Sample *** patients diagnosed with ARDS were stratified into insulin-dependent diabetes mellitus(DM)(IDDM)and non-insulindependent DM(NIDDM)*** applying exclusion criteria and matching over 20 variables,we compared cohorts for mortality,duration of mechanical ventilation,incidence of acute kidney injury(AKI),length of stay(LOS),hospitalization costs,and other clinical *** Following 1:1 propensity score matching,the analysis included 274 patients in each ***,no statistically significant differences emerged between the IDDM and NIDDM groups in terms of mortality rates(32.8%vs 31.0%,P=0.520),median hospital LOS(10 d,P=0.537),requirement for mechanical ventilation,incidence rates of sepsis,pneumonia or AKI,median total hospitalization costs,or patient disposition upon *** Compared to alternative anti-diabetic medications,outpatient insulin treatment does not appear to exert an independent influence on in-hospital morbidity or mortality in diabetic patients with non-COVID-19 ARDS.

关键词： Acute respiratory distress syndrome Type 2 diabetes mellitus Insulin Length of stay Mortality Endotracheal intubation Acute kidney injury Coronavirus disease 2019

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SYNERGISTIC EFFICACY OF ADENOVIRUS-MEDIATED BCL-XS GENE TRANSFER AND TOPOTECAN IN OVARIAN CANCER CELL

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Chinese Journal of Cancer Research 2001年第4期13卷 254-257页

作者：王和 Vicki V baker West China Second Hospital Sichuan University Chengdu 610041 China University of Michigan Comprehensive Cancer Center MI 48109-0724 USA

Objective: To observe the synergistic efficacy between Adenovirus-mediated bcl-Xs(Adv-bcl-Xs) gene transfer and chemotherapy on ovarian cancer cell growth. Methods: NuTu-19 cells were infected by different titers of Adv-bcl-Xs and treated with topotecan in the meantime. Cell proliferation was measured 3 days later by MTT. Graphical representations and statistical analyses for their interaction in tumor cells were done. Results: The statistical result and Graphical representations of the statistical modeling showed synergy effect on cell growth inhibition (P<0.01). Conclusion: There were synergistic efficacies between Adv-bcl-Xs gene therapy and Topotecan in ovarian cancer cell growth.

关键词： bcl-Xs Topotecan Ovarian Cancer

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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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Treatment with clopidogrel and proton pump inhibitors in combination: a review of emerging evidence

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Open Journal of Internal Medicine 2011年第3期1卷 45-55页

作者： david A. Johnson Danial E. baker 不详

Proton pump inhibitors often are prescribed in combination with clopidogrel to decrease risk of gastrointestinal bleeding after acute coronary syndrome. Clopidogrel is a prodrug that has to be metabolized in the liver to generate the active metabolite. Both medications are metabolized largely by the CYP2C19 enzyme;therefore, concerns exist that a drug-drug interaction during concomitant treatment with clopidogrel and a proton pump inhibitor may result in reduction of platelet inhibition. We have reviewed observational and randomized control studies that have evaluated the potential influence of proton pump inhibitors on the platelet inhibitory effect of clopidogrel, along with cardiovascular outcomes. We also have summarized regulatory and academic guidelines for treatment of patients in which concomitant therapy with clopidogrel and proton pump inhibitors may be indicated. Confounding issues, including differential effects of individual proton pump inhibitors on the pharmacodynamics of clopidogrel and variation in clopidogrel metabolism mediated by CYP2C19 gene polymorphisms, also are discussed.

关键词： Proton Pump Inhibitors Clopidogrel Dual Antiplatelet Therapy Drug-Drug Interaction Gastrointestinal Bleeding Myocardial Infarction Percutaneous Coronary Intervention

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Relationship between abdominal adiposity, cardiovascular fitness, and biomarkers of cardiovascular risk in British adolescents

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Journal of Sport and Health Science 2020年第6期9卷 634-644页

作者： Moira S.Lewitt Julien S.baker School of Health and Life Sciences University of the West of ScotlandPaisley PA12BEScotlandUK Institute of Clinical Exercise and Health Science School of Health and Life SciencesUniversity of the West of ScotlandLanarkshire G720LHScotlandUK

Background:Puberty is a critical time in the development of overweight and *** aim of this study was to examine relationships between measures of adiposity,cardiovascular fitness,and biomarkers of cardiovascular disease risk in ***:In a cross-sectional study design,129 girls and 95 boys aged 12.9-14.4 years at various stages of puberty were included,along with their mothers(n=217)and fathers(n=207).Anthropometric assessments of adiposity were made,along with cardiovascular physical fitness,using the 20-m shuttle run test,and biomarkers associated with cardiovascular risk,including glucose,insulin,triglyceride,fibrinogen,and C-reactive protein(CRP)***:Waist-to-height ratio values were similar in boys and girls and correlated positively with diastolic blood pressure,insulin,triglyceride,fibrinogen,and CRP concentrations,and inversely with cardiovascular fitness *** thickness measurements were higher in ***-molecular-weight adiponectin concentrations were lower in boys than girls,particularly in late puberty,and CRP levels were *** fitness,maternal body mass index(BMI),and paternal BMI contributed independently to the variance in waist measurements in girls and ***,triceps skinfold thickness,and weight-to-height ratio,but not parental BMI,contributed independently to the variance in cardiovascular ***:There is a relationship between measures of adolescent adiposity and parental weight that involves factors other than cardiovascular *** boys have relatively more abdominal fat than girls and a tendency to have a proinflammatory profile of *** observations suggest that family and social environmental interventions are best undertaken earlier in childhood,particularly among boys.

关键词： Adiposity Cardiovascular fitness Cardiovascular risk Inflammation Puberty

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