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膳食甘氨酸的健康保护潜力

国外畜牧学（猪与禽） 2018年第9期38卷 75-77页

作者：唐彩琰(译) 邵建忠(审) mark f.mccarty james h.o'keefe james j.dinicolantonio 不详

谷胱甘肽是一种重要的清除型抗氧化剂,可以抵抗过氧化氢的促炎信号传导。细胞谷胱甘肽水平的提高可能在预防和治疗由氧化应激引起的各种疾病上具有广泛的用途。在膳食中添加N-乙酰半胱氨酸就是出于该目的。添加甘氨酸是否能促进谷胱甘... 详细信息

谷胱甘肽是一种重要的清除型抗氧化剂,可以抵抗过氧化氢的促炎信号传导。细胞谷胱甘肽水平的提高可能在预防和治疗由氧化应激引起的各种疾病上具有广泛的用途。在膳食中添加N-乙酰半胱氨酸就是出于该目的。添加甘氨酸是否能促进谷胱甘肽的合成,为此我们利用PubMed文献数据库对相关文献进行了综述。结果发现动物机体组织中甘氨酸的水平低于甘氨酸的谷胱甘肽合成酶米氏常数(Km)。当甘氨酸供应量太少不足以维持正常的谷胱甘肽合成速度时,组织中γ-谷氨酰半胱氨酸的浓度就会升高,从而导致尿液中其替代代谢产物5-L-氧代脯氨酸的含量增多。这种代谢产物在素食者和其他食用蛋白水平相对低的膳食的人尿液中水平增加的事实强烈表明,膳食中的甘氨酸能够限制饮食正常的人体内谷胱甘肽的合成。此外,多项动物研究报道,日粮中添加甘氨酸可以增加机体组织中谷胱甘肽的含量。甘氨酸是卟啉、嘌呤、肌酸、肌氨酸和胆汁盐生物合成的前体物质,是甘氨酸门控氯离子通道的激动剂和N-甲基-D-天冬氨酸受体的协同激动剂。它可抑制蛋白质糖化,提高丙酮酸盐(一种有效的过氧化氢清除剂)在肝脏中的合成。补充甘氨酸具有改善内皮功能、预防心脏肥大、辅助控制代谢综合征、预防糖尿病并发症、抑制炎症、保护肝脏和促进有效睡眠的潜力。因此,我们有必要进行临床研究以评估甘氨酸对谷胱甘肽水平和各种疾病的影响。

关键词：乙酰半胱氨酸氯离子通道胰高血糖素胰高血糖素样肽1 谷胱甘肽谷胱甘肽合酶甘氨酸

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膳食甘氨酸的健康保护潜力(续1)

国外畜牧学（猪与禽） 2018年第10期38卷 80-82页

作者：唐彩琰王晶晶 mark f.mccarty James H.O'Keefe James J.DiNicolantonio

上期回顾：上期主要介绍了膳食甘氨酸对谷胱甘肽合成的调节作用、健康保护潜力以及甘氨酸与代谢综合征的关系等内容.5甘氨酸的抗炎作用巨噬细胞、白细胞和库普弗细胞都表达甘氨酸门控氯离子通道,在这些细胞中,甘氨酸发挥着超极化作用,... 详细信息

上期回顾：上期主要介绍了膳食甘氨酸对谷胱甘肽合成的调节作用、健康保护潜力以及甘氨酸与代谢综合征的关系等内容.5甘氨酸的抗炎作用巨噬细胞、白细胞和库普弗细胞都表达甘氨酸门控氯离子通道,在这些细胞中,甘氨酸发挥着超极化作用,其通过电压敏感的钙离子通道抑制钙的内流,从而下调它们的促炎活性。

关键词：健康保护甘氨酸膳食钙离子通道巨噬细胞代谢综合征氯离子通道调节作用

Practical strategies for modulating foam cell formation and behavior

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World Journal of Clinical Cases 2014年第10期2卷 497-506页

作者： Elisabeth Uitz Babak Bahadori mark f.mccarty Mohammed H Moghadasian Department of Internal Medicine 2 University Hospital of St. Poelten Karl Landsteiner Private University of Health and Life Sciences Catalytic Longevity Carlsbad CA 92009 United States Department of Human Nutritional Sciences University of Manitoba Winnipeg R2H 2A6 Manitoba Canada

Although high density lipoprotein(HDL)-mediated reverse cholesterol transport is crucial to the prevention and reversal of atheroma, a recent meta-analysis makes evident that current pharmaceutical strategies for modulating HDL cholesterol levels lower cardiovascular risk only to the extent that they concurrently decrease low density lipoprotein(LDL) cholesterol. This corresponds well with findings of a recent Mendelian randomization analysis, in which genetic polymorphisms associated with HDL cholesterol but no other known cardiovascular risk factors failed to predict risk for myocardial infarction. Although it is still seems appropriate to search for therapies that could improve the efficiency with which HDL particles induce reverse cholesterol transport, targeting HDL cholesterol levels per se with current measures appears to be futile. Itmay therefore be more promising to promote reverse cholesterol transport with agents that directly target foam cells. Macrophage expression of the cholesterol transport proteins adenosine triphosphate binding cassette transporter A1, adenosine triphosphate binding cassette transporter G1, and scavenger receptor class B member 1 is transcriptionally up-regulated by activated liver X receptors(LXR), whereas nuclear factor(Nf)-kappa B antagonizes their expression. Taurine, which inhibits atherogenesis in rodent studies, has just been discovered to act as a weak agonist for LXRalpha. Conversely, it may be possible to oppose Nf-kappa B activation in macrophages with a range of measures. Induction of heme oxygenase-1, which can be attained with phase 2 inducer phytochemicals such as lipoic acid and green tea catechins, promotes reverse cholesterol transport in macrophages and inhibits atherogenesis in rodents, likely due to, in large part, Nf-kappa B antagonism. Inhibition of macrophage nicotinamide adenine dinucleotide phosphate(NADPH) oxidase activity with the spirulina-derived bilirubin-mimetic phycocyanobilin may also oppose Nf-ka

关键词： Atherosclerosis Cholesterol Inflammation Phytochemical Nutraceutical Atherogenesis Plaque Cytokine Antioxidant

Modification Design Method for an Enveloping Hourglass Worm Gear with Consideration of Machining and Misalignment Errors

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Chinese Journal of Mechanical Engineering 2013年第5期26卷 948-956页

作者： DENG Xingqiao WANG Jinge HORSTEMEYER mark f School of Mechanical Engineering and Automation Xihua University Center for Advanced Vehicular Systems Mississippi State University

The influences of machining and misalignment errors play a very critical role in the performance of the anti-backlash double-roller enveloping hourglass worm gear(ADEHWG).However,a corresponding efficient method for eliminating or reducing these errors on the tooth profile of the ADEHWG is seldom *** gear engagement equation and tooth profile equation for considering six different errors that could arise from the machining and gear misalignment are derived from the theories of differential geometry and gear ***,the tooth contact analysis(TCA) is used to systematically investigate the influence of the machining and misalignment errors on the contact curves and the tooth profile by means of numerical analysis and three-dimensional solid *** research results show that vertical angular misalignment of the worm wheel(Δβ) has the strongest influences while the tooth angle error(Δα) has the weakest influences on the contact curves and the tooth profile.A novel efficient approach is proposed and used to minimize the effect of the errors in manufacturing by changing the radius of the grinding wheel and the approaching point of *** results from the TCA and the experiment demonstrate that this tooth profile design modification method can indeed reduce the machining and misalignment *** modification design method is helpful in understanding the manufacturing technology of the ADEHWG.

关键词： worm gears tooth contact analysis machining and misalignment errors tooth profile errors modification method

Runout of submarine landslide simulated with material point method

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Journal of Hydrodynamics 2017年第3期29卷 438-444页

作者： Youkou Dong Dong Wang mark f.Randolph Centre for Offshore foundation Systems the University of Western Australia Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of China

Most of the present knowledge on submarine landslides relies upon back-analysis of post-failure deposits identified using geophysical *** this paper,the runout of slides on rigid bases is explored using the material point method（MPM）with focus on the geotechnical aspects of the *** MPM,the sliding material and bases are discretised into a number of Lagrangian particles,and a background Eulerian mesh is employed to update the state of the *** morphologies of the slide can be reproduced by tracking the Lagrangian particles in the dynamic processes.A real case history of a submarine slide is back-analyzed with the MPM and also a depth-averaged *** of the slides from steep slopes to moderate bases are *** different combinations of soil and basal parameters are assumed to trigger runout mechanisms of elongation,block sliding and *** runout distances predicted by the MPM match well with those from large deformation finite element analysis for the elongation and block sliding *** and grabens are shaped in a spreading ***,the current MPM simulations for materials with high sensitivities are relatively mesh sensitive.

关键词： Submarine landslide runout morphology material point method large deformation

Quantification of ventilation enhancement using the Eye CAN roof support

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International Journal of Mining Science and Technology 2017年第1期27卷 153-158页

作者： Shook Michael T Sindelar mark f, Jiang Hua Luo Yi Burrell Mining Products Inc.New KensingtonPA 15068USA Department of Mining Engineering West Virginia UniversityMorgantownWV 26506USA

Convergence of roof and floor in underground mine openings is a common occurrence. This convergence not only adversely affects the ability of workers, equipment and supplies to travel through the mine, it also reduces the effectiveness of the mine ventilation system, which is essential for the dilution of methane gas and airborne respirable dust. While installing secondary standing supports to control floor and roof convergence, such supports, by nature, partially obstruct a portion of the airway. These added obstructions inhibit the ability of the ventilation system to operate as efficiently as it could by increasing the resistance in and reducing the cross-sectional area of the airway. This study introduces and demonstrates the benefits of The Eye CAN^(TM) standing roof support, which controls floor and roof convergence and is less obstructive to air flow than conventional wooden cribs. Laboratory findings show that the normal resistance of a supported lined airway is reduced by using this new product from Burrell Mining Products, Inc., while providing the same roof support characteristics of an established product—The CANò. Load vs. displacement curves generated from laboratory tests demonstrated that this new product behaves with the same roof support characteristics as others in The CAN product family. Ventilation data gathered from a simulated mine entry was then used for computational fluid dynamics(CfD) *** CfD analysis showed an improvement with The Eye CAN vs. other accepted forms of standing roof support. This proof-of-concept study suggests that, when using this new product made by Burrell Mining Products, Inc., not only will the convergence from the roof and floor be controlled, but airway resistance will also be reduced.

关键词： Standing roof support CAN Ventilation Load-displacement Eye CAN

Compressive and cyclic flexural response of double-hooked-end steel fiber reinforced concrete

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frontiers of Structural and Civil Engineering 2022年第9期16卷 1104-1126页

作者： Demewoz W.MENNA Aikaterini S.GENIKOMSOU mark f.GREEN Department of Civil Engineering Queen’s UniversityKingstonON K7L 3N6Canada

Recent developments on high-performance double-hooked-end steel fibers have enhanced the wide applications of steel fiber reinforced concrete(SfRC).This study presents the compressive properties and the cyclic flexural performance of the SfRC that were experimentally *** different double-hooked-end steel fibers at 0.25%,0.5%,0.75%,and 1%volume fractions were *** fiber types had similar length to diameter ratios,while the first two fiber types had similar anchorage mechanisms(4D)and tensile strength and the third type had different anchorage mechanism(5D)and a higher tensile *** increased volumetric ratio of the fibers increased the post-peak compressive strain(ductility),the tensile strength,and the cyclic flexural strength and cumulative energy dissipation characteristics of the *** the 4D fibers,the mixtures with the larger steel fibers showed higher flexural strength and more energy dissipation compared to the SfRCs with smaller size *** 1%steel fiber dosage,4D and 5D specimens showed similar cyclic flexural ***,a 3D finite element model that can predict the monotonic and cyclic flexural responses of the double-hooked-end SfRC was *** calibration process considered the results obtained from the inverse analysis to determine the tensile behavior of the SfRC.

关键词： steel fiber reinforced concrete fiber geometry cyclic loading energy dissipation finite element modeling inverse analysis

Capsule endoscopy:Current practice and future directions

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World Journal of Gastroenterology 2014年第24期20卷 7752-7759页

作者： Melissa f Hale Reena Sidhu mark E McAlindon Department of Gastroenterology Royal Hallamshire HospitalSheffield S10 2JFUnited Kingdom

Capsule endoscopy (CE) has transformed investigation of the small bowel providing a non-invasive, well tolerated means of accurately visualising the distal duodenum, jejunum and ileum. Since the introduction of small bowel CE thirteen years ago a high volume of literature on indications, diagnostic yields and safety profile has been presented. Inclusion in national and international guidelines has placed small bowel capsule endoscopy at the forefront of investigation into suspected diseases of the small bowel. Most commonly, small bowel CE is used in patients with suspected bleeding or to identify evidence of active Crohn’s disease (CD) (in patients with or without a prior history of CD). Typically, CE is undertaken after upper and lower gastrointestinal flexible endoscopy has failed to identify a diagnosis. Small bowel radiology or a patency capsule test should be considered prior to CE in those at high risk of strictures (such as patients known to have CD or presenting with obstructive symptoms) to reduce the risk of capsule retention. CE also has a role in patients with coeliac disease, suspected small bowel tumours and other small bowel disorders. Since the advent of small bowel CE, dedicated oesophageal and colon capsule endoscopes have expanded the fields of application to include the investigation of upper and lower gastrointestinal disorders. Oesophageal CE may be used to diagnose oesophagitis, Barrett’s oesophagus and varices but reliability in identifying gastroduodenal pathology is unknown and it does not have biopsy capability. Colon CE provides an alternative to conventional colonoscopy for symptomatic patients, while a possible role in colorectal cancer screening is a fascinating prospect. Current research is already addressing the possibility of controlling capsule movement and developing capsules which allow tissue sampling and the administration of therapy.

关键词： Capsule endoscopy Small bowel Indications Technology Oesophageal Colon

Effect of process parameters on the density and porosity of laser melted AlSi10Mg/SiC metal matrix composite

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frontiers of Mechanical Engineering 2018年第4期13卷 520-527页

作者： Omotoyosi H. fAMODIMU mark STANfORD Chike f. ODUOZA Lijuan ZHANG faculty of Science and Engineering School of Engineering Telford Campus University of Wolverhampton WV1 1LY Wolverhampton UK

Laser melting of aluminium alloy-AlSi10Mg has increasingly been used to create specialised products in various industrial applications, however, research on utilising laser melting of aluminium matrix composites in replacing specialised parts have been slow on the uptake. This has been attributed to the complexity of the laser melting process, metal/ceramic feedstock for the process and the reaction of the feedstock material to the laser. Thus, an understanding of the process, material microstructure and mechanical properties is important for its adoption as a manufacturing route of aluminium metal matrix composites. The effects of several parameters of the laser melting process on the mechanical blended composite were thus investigated in this research. This included single track formations of the matrix alloy and the composite alloyed with 5% and 10% respectively for their reaction to laser melting and the fabrication of density blocks to investigate the relative density and porosity over different scan speeds. The results from these experiments were utilised in determining a process window in fabricating near-fully dense parts.

关键词： selective laser melting additive manufacturing mechanical alloying powder metallurgy aluminium metal matrix composite