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Impact shock frequency components and attenuation in rearfoot and forefoot running

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Journal of Sport and health Science 2014年第2期3卷 113-121,153+157页

作者： allison h.gruber Katherine A.Boyer Timothy R.Derrick Joseph hamill Biomechanics Laboratory University of Massachusetts Amherst Biomechanics Laboratory Iowa State University

Background:The forefoot running footfall pattern has been suggested to reduce the risk of developing running related overuse injuries due to a reduction of impact related variables compared with the rearfoot running footfall ***,only time-domain impact variables have been compared between footfall *** frequency content of the impact shock and the degree to which it is attenuated may be of greater importance for injury risk and prevention than time-domain ***,the purpose of this study was to determine the differences in head and tibial acceleration signal power and shock attenuation between rearfoot and forefoot ***:Nineteen habitual rearfoot runners and 19 habitual forefoot runners ran on a treadmill at 3.5 m/s using their preferred footfall patterns while tibial and head acceleration data were *** magnitude of the first and second head acceleration peaks,and peak positive tibial acceleration were *** power spectral density of each signal was calculated to transform the head and tibial accelerations in the frequency *** attenuation was calculated by a transfer function of the head signal relative to the ***:Peak positive tibial acceleration and signal power in the lower and higher ranges were significantly greater during rearfoot than forefoot running(/> he first and second head acceleration peaks and head signal power were not statistically different between patterns(p > 0.05).Rearfoot running resulted in significantly greater shock attenuation for the lower and higher frequency ranges as a result of greater tibial acceleration(p he difference in impact shock frequency content between footfall patterns suggests that the primary mechanisms for attenuation may *** relationship between shock attenuation mechanisms and injury is not clear but given the differences in impact frequency content,neither footfall pattern may be more benefi

关键词： Frequency domain Impact shock Running footfall patterns Shock attenuation Tibial acceleration

The evolutionary development of plant-feeding insects and their nutritional endosymbionts

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Insect Science 2017年第6期24卷 910-928页

作者： Isabel h. Skidmore allison K. hansen Department of Entomology University of Illinois Urbana-Champaign Ilfinois USA

herbivorous insects have evolved diverse mechanisms enabling them to feed on plants with suboptimal nutrient availability. Low nutrient availability negatively impacts insect herbivore development and fitness. To overcome this obstacle numerous insect lineages have evolved intimate associations with nutritional endosymbionts. This is especially true for insects that specialize on nitrogen-poor substrates, as these insects are highly dependent on intraceUular symbionts to provide nitrogen lacking in their insect host＇s diet. Emerging evidence in these systems suggest that the symbiont＇s and/or the insect＇s biosynthetic pathways are dynamically regulated throughout the insect＇s development to potentially cope with the insect＇s changing nutritional demands. In this review, we evaluate the evolutionary development of symbiotic insect cells （bacteriocytes） by comparing and contrasting genes and mechanisms involved in maintaining and regulating the nutritional symbiosis throughout insect development in a diversity of insect herbivore-endosymbiont associations. With new advances in genome sequencing and functional genomics, we eval- uate to what extent nutritional symbioses are shaped by （i） the regulation of symbiont titer, （ii） the regulation of insect symbiosis genes, and （iii） the regulation of symbiont genes. We discuss how important these mechanisms are for the biosynthesis of essential amino acids and vitamins across insect life stages in divergent insect-symbiont systems. We conclude by suggesting future directions of research to further elucidate the evolutionary development of bacteriocytes and the impact of these nutritional symbioses on insect plant interactions.

关键词： development evolutionary insect herbivores plant-insect microbe interactions symbiosis

Understanding of the influence of process parameters on the heat transfer behavior at the metal/die interface in high pressure die casting process

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Science China(Technological Sciences) 2009年第1期52卷 172-175页

作者： allison John Research & Advanced Engineering Department Scientific Research Laboratory Ford Motor Company

The current paper focuses on the influence of the process parameters on the peak values of the inter-facial heat transfer coefficient (IhTC) at metal/die interface during high pressure die casting (hPDC) process. A "step shape" casting and AM50 alloy were used during the experiment. The IhTC was de-termined by solving the inverse thermal problem based on the measured temperature inside the die. Results show that the initial die surface temperature (IDST, TDI) has a dominant influence while the casting pressure and fast shot velocity have a secondary influence on the IhTC peak values. By curve fitting, it was found that the IhTC peak value (hmax) changes as a function of the IDST in a manner of hmax =eαTγDI. Such relationship between the IhTC peak value and the IDST can also be found when the casting alloy is ADC12, indicating that this phenomenon is a common characteristic in the hPDC process.

关键词： high pressure die casting interfacial heat transfer coefficient AM50 ADC12

Oxidative stress, respiratory muscle dysfunction, and potential therapeutics in chronic obstructive pulmonary disease

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Frontiers in Biology 2012年第6期7卷 506-513页

作者： Li ZUO allison h. hALLMAN Marvin K. YOUSIF Michael T. ChIEN Molecular Physiology and Biophysics Laboratory Department of Biological Sciences Oakland University Rochester MI 48309 USA Department of Biology Kalamazoo College Kalamazoo MI 49006 USA

Chronic obstructive pulmonary disease （COPD） is a highly relevant disorder that induces respiratory muscle dysfunction. One prevalent symptom of COPD is resistive breathing which causes respiratory muscle to significantly increase the magnitude of contractions, resulting in reactive oxygen species （ROS） formation and oxidative stress. Through cellular signaling cascades, ROS activate molecules such as mitogen-activated protein kinases and nuclear factor-kB. These signaling molecules stimulate the release of cytokines which in turn cause damage to the diaphragm, involving sarcomeric disruptions. In response to COPD induced fatigue, the diaphragm undergoes a beneficial fibertype shift to type I muscle fibers, which are more resistant to hypoxia than type II fibers. The lung hyperinflation that occurs in COPD also causes intercostal muscle dysfunction, thereby exacerbating COPD symptoms. In addition, COPD is known to have a connection with heart failure, diabetes, and aging, further decreasing respiratory function. Currently, there is no cure for this disorder. Nevertheless, various potential therapeutic strategies focusing on respiratory muscle have been identified including respiratory muscle training, β2-agonist therapy, and lung volume reduction surgery. In this review, we will outline the role of COPD, oxidative stress, and related complications in respiratory muscle dysfunction.

关键词： COPD diaphragm ROS cytokine respiratory therapy

North Atlantic subtropical mode water formation controlled by Gulf Stream fronts

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National Science Review 2023年第9期10卷 214-223页

作者： Bolan Gan Jingjie Yu Lixin Wu Gokhan Danabasoglu R.Justin Small allison h.Baker Fan Jia Zhao Jing Xiaohui Ma haiyuan Yang Zhaohui Chen Frontier Science Center for Deep Ocean Multispheres and Earth System(FDOMES) and Physical Oceanography Laboratory Ocean University of China 2. Laoshan Laboratory National Center for Atmospheric Research CAS Key Laboratory of Ocean Circulation and Waves Institute of Oceanology Chinese Academy of Sciences

The North Atlantic Ocean hosts the largest volume of global subtropical mode waters(STMWs) in the world,which serve as heat,carbon and oxygen silos in the ocean *** are formed in the Gulf Stream region where thermal fronts are pervasive and result in feedback with the ***,their roles in STMW formation have been *** eddy-resolving global climate simulations,we find that suppressing local frontal-scale ocean-to-atmosphere(FOA) feedback leads to STMW formation being reduced almost by *** is because FOA feedback enlarges STMW outcropping,attributable to the mixed layer deepening associated with cumulative excessive latent heat loss due to higher wind speeds and greater air-sea humidity contrast driven by the Gulf Stream *** enhanced heat loss overshadows the stronger restratification induced by vertical eddies and turbulent heat transport,making STMW colder and he *** more realistic representation of FOA feedback,the eddy-present/rich coupled global climate models reproduce the observed STMWs much better than the eddy-free *** improvement in STMW production cannot be achieved,even with the oceanic resolution solely refined but without coupling to the overlying atmosphere in oceanic general circulation *** findings highlight the need to resolve FOA feedback to ameliorate the common severe underestimation of STMW and associated heat and carbon uptakes in earth system mo dels.

关键词： North Atlantic subtropical mode water Gulf Stream thermal fronts frontal-scale ocean-to-atmosphere feedback eddy-resolving coupled global climate model

压铸过程中铸件-铸型界面换热系数与铸件凝固速率的关系

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金属学报 2009年第1期45卷 102-106页

作者：郭志鹏熊守美 Mei Li John allison 清华大学机械工程系先进成形制造教育部重点实验室北京100084 Research ＆ Advanced Engineering Department Scientific Research Laboratory Ford Motor Company Dearborn MI 48121 USA

在实际压铸实验的基础上,求解了铸件-铸型界面换热系数h与铸件凝固速率v的关系.结果表明,二者呈线性变化关系:h=k_(h-v)·v+ω(其中,斜率k_(h-v)为铸型初始表面温度及铸件厚度的函数,ω为常数);通过线性拟合确定k_(h-v)和ω值,从而确立... 详细信息

在实际压铸实验的基础上,求解了铸件-铸型界面换热系数h与铸件凝固速率v的关系.结果表明,二者呈线性变化关系:h=k_(h-v)·v+ω(其中,斜率k_(h-v)为铸型初始表面温度及铸件厚度的函数,ω为常数);通过线性拟合确定k_(h-v)和ω值,从而确立换热系数与铸件凝固速率的关系.这种关系同时适用于镁合金AM50和铝合金ADC12.

关键词：压铸界面换热系数凝固速率镁合金AM50 铝合金ADC12

Magnetic resonance imaging-guided focused ultrasound to increase localized blood-spinal cord barrier permeability

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Neural Regeneration Research 2017年第12期12卷 2045-2049页

作者： allison h.Payne Gregory W.hawryluk Yoshimi Anzai henrik Odéen Megan A.Ostlie Ethan C.Reichert Amanda J.Stump Satoshi Minoshima Donna J.Cross Department of Radiology and Imaging Sciences University of Utah Salt Lake City UT USA Department of Neurosurgery University of Utah Salt Lake City UT USA

Spinal cord injury（SCI） affects thousands of people every year in the USA, and most patients are left with some permanent paralysis. Therapeutic options are limited and only modestly affect outcome. To address this issue, we used magnetic resonance imaging-guided focused ultrasound（MRg FUS） as a non-invasive approach to increase permeability in the blood-spinal cord barrier（BSCB）. We hypothesize that localized, controlled sonoporation of the BSCB by MRg FUS will aid delivery of therapeutics to the injury. here, we report our preliminary findings for the ability of MRg FUS to increase BSCB permeability in the thoracic spinal cord of a normal rat model. First, an excised portion of normal rat spinal column was used to characterize the acoustic field and to estimate the insertion losses that could be expected in an MRg FUS blood spinal cord barrier opening. Then, in normal rats, MRg FUS was applied in combination with intravenously administered microbubbles to the spinal cord region. Permeability of the BSCB was indicated as signal enhancement by contrast administered prior to T1-weighted magnetic resonance imaging and verified by Evans blue dye. Neurological testing using the Basso, Beattie, and Breshnahan scale and the ladder walk was normal in 8 of 10 rats tested. Two rats showed minor impairment indicating need for further refinement of parameters. No gross tissue damage was evident by histology. In this study, we have opened successfully the blood spinal cord barrier in the thoracic region of the normal rat spine using magnetic resonance-guided focused ultrasound combined with microbubbles.

关键词： focused ultrasound spinal cord magnetic resonance imaging contrast-enhanced blood-spinalcord barrier

A challenging case of alpha-fetoprotein-result discrepancies in a patient with chronic hepatitis B

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Gastroenterology Report 2020年第6期8卷 484-486,I0003页

作者： Pir A.Shah allison Onken Rizwan Ishtiaq Muhammad h.Maqsood Shyam S.Patel Karen J.Campoverde Reyes Adrianna Z.herskovits Daryl T.Y.Lau Department of Medicine Liver CenterDivision of GastroenterologyBeth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMAUSA Department of Pathology Beth Israel Deaconess Medical CenterHarvard Medical SchoolBostonMAUSA

Introduction Alpha-fetoprotein(AFP)is the most abundant serum protein found in the human fetus,produced by the yolk sac and the liver[1].The levels of maternal serum AFP reach a peak value at28-32 weeks of gestation and decrease rapidly after birth and usually drop to the normal at 8-12 months of *** normal serum AFP level for an adult ishesize and secrete an increased level of *** ultrasound and AFP are generally recommended as the screening modality for hCC for patients at risk for development of hepatocellular carcinoma(hCC)[1].AFP-L3,an isoform of AFP that binds Lens culinaris agglutinin,can be particularly useful in the early identification of aggressive hCC[2].These assays,however,can generate false-positive and false-negative AFP *** patients with advanced hCC,20%had normal AFP levels,whereas some patients with liver diseases had significant AFP elevation without liver cancer in long-term surveillance[3].Elevated AFP levels could be associated with active liver diseases with hepatocyte regeneration[4,5].In that setting,the AFP level will decline with improvement of the underlying liver *** case illustrated the dilemma and uncertainties as a result of persistent abnormal AFP values after extensive clinical investigations.

关键词：甲胎蛋白 fetus false

Layer-by-layer functionalized nanotube arrays:A versatile microfluidic platform for biodetection

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Microsystems & Nanoengineering 2015年第1期1卷 1-7页

作者： allison L.Yost Setareh Shahsavari Grinia M.Bradwell Roberta Polak Fabio Fachin Robert E.Cohen Gareth h.McKinley Mehmet Toner Michael F.Rubner Brian L.Wardle Department of Mechanical Engineering Massachusetts Institute of Technology77 Massachusetts AvenueCambridgeMA 02139USA Department of Materials Science and Engineering Massachusetts Institute of Technology77 Massachusetts AvenueCambridgeMA 02139USA Department of Chemical Engineering Massachusetts Institute of Technology77 Massachusetts AvenueCambridgeMA 02139USA Department of Aeronautics and Astronautics Massachusetts Institute of Technology77 Massachusetts AvenueCambridgeMA 02139USA Center for Engineering in Medicine and BioMEMS Resource Center Massachusetts General HospitalHarvard Medical Schooland Shriners Hospital for ChildrenBostonMA 02139USA

We demonstrate the layer-by-layer(LbL)assembly of polyelectrolyte multilayers(PEM)on three-dimensional nanofiber *** porosity(99%)aligned carbon nanotube(CNT)arrays are photolithographically patterned into elements that act as textured scaffolds for the creation of functionally coated(nano)porous ***-scale bilayers of poly(allylamine hydrochloride)/poly(styrene sulfonate)(PAh/SPS)are formed conformally on the individual nanotubes by repeated deposition from aqueous solution in microfluidic *** and experimental results show that the LbL deposition is dominated by the diffusive transport of the polymeric constituents,and we use this understanding to demonstrate spatial tailoring on the patterned nanoporous elements.A proof-of-principle application,microfluidic bioparticle capture using N-hydroxysuccinimide-biotin binding for the isolation of prostate-specific antigen(PSA),is demonstrated.

关键词： layer-by-layer carbon nanotube microfluidic nanoporous functionalization bioparticle capture