检索结果-南通市图书馆

From contraction to gene expression:nanojunctions of the sarco/endoplasmic reticulum deliver site-and function-specific calcium signals

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2016年第8期59卷 749-763页

作者： A.mark evans Nicola Fameli Oluseye A.Ogunbayo Jingxian Duan Jorge Navarro-Dorado Centre for Integrative Physiology College of Medicine and Veterinary MedicineHugh Robson BuildingUniversity of EdinburghEdinburgh EH8 9XDUK Institute of Biophysics Medical University of GrazGraz 8010Austria

Calcium signals determine, for example, smooth muscle contraction and changes in gene expression. How calcium signals select for these processes is enigmatic. We build on the "panjunctional sarcoplasmic reticulum" hypothesis, describing our view that different calcium pumps and release channels, with different kinetics and affinities for calcium, are strategically positioned within nanojunctions of the Sr and help demarcate their respective cytoplasmic nanodomains. SErCA2 b and ry r1 are preferentially targeted to the sarcoplasmic reticulum(Sr) proximal to the plasma membrane(PM), i.e., to the superficial buffer barrier formed by PM-Sr nanojunctions, and support vasodilation. In marked contrast, SErCA2 a may be entirely restricted to the deep, perinuclear Sr and may supply calcium to this sub-compartment in support of vasoconstriction. ry r3 is also preferentially targeted to the perinuclear Sr, where its clusters associate with lysosome-Sr nanojunctions. The distribution of ry r2 is more widespread and extends from this region to the wider cell. Therefore, perinuclear ry r3 s most likely support the initiation of global calcium waves at L-Sr junctions, which subsequently propagate by calcium-induced calcium release via ry r2 in order to elicit contraction. Data also suggest that unique SErCA and ry r are preferentially targeted to invaginations of the nuclear membrane. Site- and function-specific calcium signals may thus arise to modulate stimulus-response coupling and transcriptional cascades.

关键词： calcium nanojunction ryanodine receptor sarco/endoplasmic reticulum calcium ATPase smooth muscle gene expression contraction

Searching for a route to synthesize in situ epitaxial Pr_(2)Ir_(2)O_(7) thin films with thermodynamic methods

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2021年第1期7卷 1320-1325页

作者： Lu Guo Shun-Li Shang Neil Campbell Paul G.evans mark rzchowski Zi-Kui Liu Chang-Beom Eom Department of Materials Science and Engineering University of Wisconsin-MadisonMadisonWisconsinUSA Department of Materials Science and Engineering The Pennsylvania State UniversityUniversity ParkPennsylvaniaUSA Department of Physics University of Wisconsin-MadisonMadisonWisconsinUSA

In situ growth of pyrochlore iridate thin films has been a long-standing challenge due to the low reactivity of Ir at low temperatures and the vaporization of volatile gas species such as IrO_(3)(g)and IrO_(2)(g)at high temperatures and high PO_(2).To address this challenge,we combine thermodynamic analysis of the Pr-Ir-O_(2)system with experimental results from the conventional physical vapor deposition(PVD)technique of *** results indicate that only high growth temperatures yield films with crystallinity sufficient for utilizing and tailoring the desired topological electronic properties and the in situ synthesis of Pr_(2)Ir_(2)O_(7)thin films is fettered by the inability to grow with PO_(2)on the order of 10 Torr at high temperatures,a limitation inherent to the PVD ***,we suggest techniques capable of supplying high partial pressure of key species during deposition,in particular chemical vapor deposition(CVD),as a route to synthesis of Pr_(2)Ir_(2)O_(7).

关键词： process thermodynamic synthesis

Modeling the Spatial Distribution of Soil Heavy Metals Using random Forest Model—A Case Study of Nairobi and Thirirka rivers’ Confluence

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Geographic Information System 2020年第6期12卷 597-619页

作者： evans Omondi mark Boitt Department of Geomatic Engineering and Geospatial Information Systems Jomo Kenyatta University of Agriculture and Technology Nairobi Kenya

Modeling the spatial distribution of soil heavy metals is important in determining the safety of contaminated soils for agricultural use. This study utilized 60 topsoil samples (0 - 30 cm), multispectral images (Sentinel-2), spectral indices, and ancillary data to model the spatial distribution of heavy metals in the soils along the Nairobi river. The model was generated using the random Forest package in r. Using r2 to assess the prediction accuracy, the random Forest model generated satisfactory results for all the elements. It also ranked the variables in order of their importance in the overall prediction. Spectral indices were the most important variables within the rankings. From the predicted topsoil maps, there were high concentrations of Cadmium on the easterly end of the river. Cadmium is an impurity in detergents, and this section is in close proximity to the Nairobi water sewerage plant, which could be a direct source of Cadmium. Some farms had Zinc levels which were above the World Health Organization recommended limit. The random Forest model performed satisfactorily. However, the predictions can be improved further if the spatial resolutions of the various variables are increased and through the addition of more predictor variables.

关键词： random Forest Sentinel 2 Heavy Metals Spectral Indices Spatial Modeling

Effect of mucin 4 allele on susceptibility to experimental infection with enterotoxigenic F4 Escherichia coli in pigs fed experimental diets

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Animal Science and Biotechnology 2019年第4期10卷 981-989页

作者： Samantha O.Sterndale Danica J.evans Josephine P.Mansfield Julie Clarke Shafi Sahibzada Sam Abraham mark O’Dea David W.Miller Jae Cheol Kim John r.Pluske Agriculture Sciences College of ScienceHealthEngineering and Education Murdoch UniversityMurdochWA 6150Australia CSIrO Health and Biosecurity PO BOX 10041AdelaideBC 5000Australia Antimicrobial resistance and Infectious Disease Laboratory Murdoch UniversityMurdochWA 6150Australia AB Vista Asia Pte.Ltd The MezzoWhampoa 329682Singapore

Background: This study investigated the validity of the DNA-marker based test to determine susceptibility to ETECF4 diarrhoea by comparing the results of two DNA sequencing techniques in weaner pigs following experimental infection with F4 enterotoxigenic Escherichia coli(ETEC-F4). The effects of diet and genetic susceptibility were assessed by measuring the incidence of piglet post-weaning diarrhoea(PWD), faecal E. coli shedding and the diarrhoea ***: A DNA marker-based test targeting the mucin 4 gene(MUC4) that encodes F4 fimbria receptor identified pigs as either fully susceptible(SS), partially or mildly susceptible(Sr), and resistant(rr) to developing ETEC-F4 diarrhoea. To further analyse this, DNA sequencing was undertaken, and a significantly higher proportion of C nucleotides was observed for rr and Sr at the Xba I cleavage site genotypes when compared to SS. However, no significant difference was found between Sr and rr genotypes. Therefore, results obtained from Sanger sequencing retrospectively allocated pigs into a resistant genotype(MUC4–), in the case of a C nucleotide, and a susceptible genotype(MUC4+), in the case of a G nucleotide, at the single nucleotide polymorphism site. A total of 72 weaner pigs(age ~ 21 days), weighing 6.1 ± 1.2 kg(mean ± SEM), were fed 3 different diets:(i) positive control(PC) group supplemented with 3 g/kg zinc oxide(Zn O),(ii) negative control(NC) group(no Zn O or HAMSA),and(iii) a diet containing a 50 g/kg high-amylose maize starch product(HAMSA) esterified with acetate. At days five and six after weaning, all pigs were orally infected with ETEC(serotype O149:F4;toxins LT1, ST1, ST2 and EAST). The percentage of pigs that developed diarrhoea following infection was higher(P = 0.05) in MUC4+ pigs compared to MUC4– pigs(50% vs. 26.8%, respectively). Furthermore, pigs fed Zn O had less ETEC-F4 diarrhoea(P = 0.009) than pigs fed other diets, however faecal shedding of ETEC was similar(P > 0.05) between ***

关键词： Diarrhoea Escherichia coli F4 MUC4 Weaner pigs Zinc oxide

Prenatal Testing or Screening?

在线全文

学校读者我要写书评

暂无评论

Maternal-Fetal Medicine 2020年第4期2卷 217-222页

作者： evans mark I. evans Shara M. Fetal Medicine Foundation of America New YorkNY 10065USA Comprehensive Genetics New YorkNY 10065USA Department of Obstetrics&Gynecology Icahn School of Medicine at Mt.SinaiNew YorkNY 10029USA Department of Maternal Child Health Gillings School of Public Health University of North Carolina at Chapel HillChapel HillNY 27599USA

Over the past 50 years,the scope and extent of prenatal diagnosis and screening for genetic disorders have improved *** has been a pendulum like swing from testing to screening back and forth as new technologies *** concurrent developments of cell free fetal DNA analysis of maternal blood has dramatically changed patient’s choices towards ***,with the use of array comparative genomic hybridization of fetal DNA that requires diagnostic procedures(Chorionic villus sampling and amniocentesis),much more extensive diagnosis can be *** noninvasive methods can replicate what can be done with diagnostic procedures there still will be a"price to be paid"for opting for the non-invasive methods.

关键词： Genetic counseling Prenatal diagnosis Chorionic villus sampling Amniocentesis Array comparative genomic hybridization Noninvasive prenatal testing

From contraction to gene expression: nanojunctions of the sarcoplasmic reticulum deliver function-specific calcium signals

在线全文

学校读者我要写书评

暂无评论

From contraction to gene expression: nanojunctions of the sa...

Avulsion Dynamics in a river with Alternating Bedrock and Alluvial reaches, Huron river, Northern Ohio (USA)

第十一届全国钙信号和细胞功能研讨会

作者： A.mark evans Centre for Integrative Physiology College of Medicine and Veterinary Medicine Hugh Robson Building University of Edinburgh

Calcium signals determine smooth muscle contraction and the switch from acontractile to a migratory-proliferative phenotype（s）, which requires changes in geneexpression. However the mechanism by which different calcium signals select for these processes is enigmatic. We have shown that SErCA2 b and ry r1 arepreferentially targeted to the sarcoplasmic reticulum（Sr） proximal to the plasmamembrane（PM;Clark et al., 2010）, i.e., to the superficial buffer barrier formed by PM-Sr nanojunctions（van Breemen et al., 2013）, and support vasodilation. Here, increases in SErCA2 b activity may remove calcium from the deeper cytoplasm to the superficial Sr, from which calcium sparks may be released into the PM-Sr junction via ry r1 to activate PM resident BKCa channels, driving hyperpolarisation（Boittin et al., 2003）, removal of calcium from the cell by forward mode NCX activity and ultimately vasodilation（Boittin et al., 2003;Clark et al., 2010）. In marked contrast, SErCA2 a is entirely restricted to the deep, perinuclear Sr（Clark et al.,2010） and may function to recycle calcium into this subcompartment in support of vasoconstriction（Dipp ＆ evans, 2001;Kinnear et al., 2004;Clark et al., 2010）. Importantly, ry r3 is also preferentially targeted to the perinuclear Sr and associated lysosome-Sr nanojunctions（Kinnear et al., 2004, Kinnear et al., 2008）, while the distribution of ry r2 is more widespread and extends from this region to the wider cell（Kinnear et al., 2008;Clark et al., 2010）. We therefore proposed that perinuclear clusters of ry r3 may act as an initiation site for propagating calcium waves and contraction（Dipp ＆ evans, 2001;Kinnear et al., 2008）. Thereafter, by calcium-induced calcium release, ry r2 may carry propagating calcium waves away from perinuclear clusters of ry r3 and across the myofilaments to enhance myocyte contraction（Kinnear et al., 2008;Clark et al., 2010）. A third subtype of SErCA pump in PASMCs, namely SErCA1, and ry r1 preferentially lines invaginati

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Open Journal of Modern Hydrology 2019年第1期9卷 20-39页

作者： mark J. Potucek James E. evans Arizona Department of Water resources Phoenix AZ USA Department of Geology Bowling Green State University Bowling Green OH USA

The Huron river consists of alternating bedrock reaches and alluvial reaches. Analysis of historical aerial photography from 1950-2015 reveals six major channel avulsion events in the 8-km study area. These avulsions occurred in the alluvial reaches but were strongly influenced by the properties of the upstream bedrock reach (“inherited characteristics”). The bedrock reaches aligned with the azimuth of joint sets in the underlying bedrock. One inherited characteristic in the alluvial reach downstream is that the avulsion channels diverged only slightly from the orientation of the upstream bedrock channel (range 2 °- 38 °, mean and standard deviation 12.1 °± 13.7 °). A second inherited characteristic is that avulsion channels were initiated from short distances downstream after exiting the upstream bedrock channel reach (range 62 - 266 m, mean and standard deviation 143.7 ± 71.0 m), which is a fraction of the meander wavelength (1.2 km). Field evidence shows that some avulsion channel sites were re-occupied episodically. In addition, two properties were necessary for channel avulsions: 1) avulsion events were triggered by channel-forming hydrologic events (5-year recurrence interval flows), but not every channel-forming hydrologic event resulted in an avulsion, and 2) channel sinuosity (P) increased to 1.72 - 1.77 prior to an avulsion then decreased to 1.65 - 1.70 following an avulsion, suggesting that P ≥ 1.72 is the “critical sinuosity” or triggering value for avulsions on the Huron river. In summary, for this river consisting of alternating bedrock and alluvial reaches, the bedrock reaches impose certain parameters on downstream alluvial reaches (including sediment supply, channel direction and avulsion channel position downstream after exiting a bedrock reach) while adjustments in sinuosity and sediment storage occur in the alluvial reaches.

关键词： Avulsion Bedrock Channels Alluvial Channels Cut-Offs Historical Changes Fluvial Sediment Budgets

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

满洲鳄:中国辽宁晚中生代半水生爬行动物

现代地质 2000年第3期14卷 323-326页

作者：高克勤 Susan E.evans 季强 mark Norell 姬书安 American Museum of Natural History 纽约10024 University College London 中国地质博物馆北京100034

发现于辽宁西部凌源晚侏罗世 /早白垩世非海相义县组中的满洲鳄 ( Monjurosuchus)化石新材料 ,为解决其系统位置这一长久争议的问题提供了确切的实物依据 :满洲鳄为双孔型离鳄类 ( Choristodera)爬行动物中一较原始成员。保存精美的、... 详细信息

发现于辽宁西部凌源晚侏罗世 /早白垩世非海相义县组中的满洲鳄 ( Monjurosuchus)化石新材料 ,为解决其系统位置这一长久争议的问题提供了确切的实物依据 :满洲鳄为双孔型离鳄类 ( Choristodera)爬行动物中一较原始成员。保存精美的、独一无二的表皮构造使我们对该类中生代爬行动物的外表特征有了新的认识。满洲鳄四足具蹼 ,它至少是半水生的。

关键词：满洲鳄系统关系晚中生代半水生爬行动物

Evolving Frameworks for the Foundation and Practice of Electronic Fetal Monitoring

在线全文

学校读者我要写书评

暂无评论

Maternal-Fetal Medicine 2022年第2期4卷 141-151页

作者： mark I.evans David W.Britt Shara M.evans Lawrence D.Devoe Fetal Medicine Foundation of America New YorkNY 10065USA Comprehensive Genetics PLLCNew YorkNY 10065USA Department of Obstetrics&Gynecology Icahn School of Medicine at Mt.SinaiNew YorkNY10029USA Department of Maternal Child Health Gillings School of Public Health University of North Carolina at Chapel HillChapel HillNY 27599USA Department of Obstetrics and Gynecology Medical College of GeorgiaAugusta UniversityAugustaGA 30907USA.

Since the 1970s,electronic fetal monitoring(EFM)also known as cardiotocography(CTG)has been used extensively in labor around the world,despite its known failure to help prevent many babies from developing neonatal encephalopathy and cerebral *** of EFM’s poor performance with respect to these outcomes arises from a fundamental misunderstanding of the differences between screening and diagnostic tests,subjective classifications of fetal heart rate(FHr)patterns that lead to large inter-observer variability in its interpretation,failure to appreciate early stages of fetal compromise,and poor statistical modeling for its use as a screening *** have developed a new approach to the practice and interpretation of EFM called the fetal reserve index(FrI)which does the following:(1)breaking FHr components down into 4 components,(heart rate,variability,accelerations,and decelerations);(2)contextualizing the metrics by adding increased uterine activity;(3)adding specific maternal,fetal,and obstetric risk *** result is an eight-point scoring metric that,when directly compared with current American College of Obstetricians and Gynecologists EFM categories,even in version 1.0 with equal weighting of variables,shows that the FrI has performed much better for identifying cases at risk before damage had occurred,reducing the need for emergency deliveries,and lowering overall Cesarean delivery *** increased data,we expect further refinements in the specifics of scoring that will allow even earlier detection of compromise in labor.

关键词： Fetal monitoring Cardiotocography Fetal reserve index