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Effect of temperature on deep lined circular tunnels in transversely anisotropic elastic rock

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Underground Space 2016年第2期1卷 79-93页

作者： Tao Fei Bobet antonio Lyles School of Civil Engineering Purdue UniversityWest LafayetteINUSA Department of Geotechnical Engineering Tongji UniversityShanghaiChina

Considerably less attention has been given to thermal stresses in a *** changes in the ground or inside the tunnel,*** to fire,can cause cracking and damage to the liner and surrounding *** study derived analytical solutions for stresses and displacements caused by thermal load for a lined circular tunnel under a transversely anisotropic ground where the ground anisotropy axis coincides with the stacking *** FEM code ABAQUS was used to study a lined deep tunnel when the ground anisotropy axis is perpendicular to the stacking direction.A parametric study was performed to investigate the effects of Young’s modulus,Poisson’s ratio,thermal conductivity and the coefficient of thermal expansion on the behavior of the liner and *** results show that the Young’s modulus and the coefficient of thermal expansion are the most important parameters that determine the stresses and displacements of the liner and *** analysis also shows that the thermal conductivity has a significant effect on the temperature distribution in the ground.

关键词： Deep tunnel Circular liner Transversely anisotropic ground Thermal stresses

The Effect of Nano-Alumina Particles Generated in Situ in the Matrix of Ultralow and No Cement 85 wt%Al_(2)O_(3) Refractory Castables

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Journal of Materials Science and Chemical Engineering 2019年第6期7卷 7-22页

作者： josé antonio Alves Júnior Joao Baptista Baldo Department of Materials Engineering Federal University of Sao Carlos via Washington LuisSao CarlosSPBrazil

Advanced high alumina refractory castables of ultra-low and to cement types, are well-known because of their ability on developing similar and/or superior thermal and mechanical properties. Following the recent trend of including nanoparticles in refractory castables, in this work, it is presented a novel way to obtain the benefit effects on the thermal and mechanical properties, promoted by the development in situ, of alumina’s nanoparticles in the matrix of castable (85 wt% Al2O3). The alumina nanoparticles were originated in situ after firing, due to the pyrolysis and oxidation of an aqueous resin, produced by the Pechini process. The resin played a double role, one as mixing liquid vehicle and the other as the aluminum oxide nanoparticles precursor. The results indicate a strong increase in flexural strength and elastic modulus as well as leading to a higher residual strength after thermal shock.

关键词： Low Cement Refractory Castable Alumina Nanoparticles Elastic Modulus Impulse Excitation Technique

Polyphenols as potential enhancers of stem cell therapy against neurodegeneration

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Neural Regeneration Research 2022年第10期17卷 2093-2101页

作者： Diana Rodríguez-Vera antonio Abad-García Nancy Vargas-Mendoza Rodolfo Pinto-Almazán Eunice D.Farfán-García josé A.Morales-González Marvin A.Soriano-Ursúa Sección de Estudios de Posgrado e Investigación.Escuela Superior de Medicina Instituto Politécnico NacionalMéxico CityMéxico Unidad de Investigación Hospital Regional de Alta Especialidad IxtapalucaCarretera Federal México-Puebla km 34.5State of MéxicoMéxico

The potential of polyphenols for treating chronic-degenerative diseases(particularly neurodegenerative diseases)is ***,the selection of the best polyphenol for each treatment,the mechanisms by which they act,and their efficacy are frequently *** this review,the basics and the advances in the field,as well as suggestions for using natural and synthetic polyphenols alone or in a combinatorial strategy with stem cell assays,are compiled and ***,stem cells exhibit several responses when polyphenols are added to their environment,which could provide us with knowledge for advancing the elucidation of the origin of *** also,polyphenols are being included in the innovative strategies of novel therapies for treating neurodegenerative diseases as well as metabolic diseases related to *** this regard,flavonoid compounds are suggested as the best natural polyphenols due to their several mechanisms for acting in ameliorative effects;but increasing reports are involving other *** if some facts limiting bioactivity prevent them from conventional use,some natural polyphenols and derivatives hold the promise for being improved compounds,judged by their induced *** current results suggest polyphenols as enhancers of stem cell therapy against the targeted diseases.

关键词： Alzheimer’s disease chronic degenerative diseases combinatorial therapy metabolism neurodegenerative diseases neuronal damage neuroprotection Parkinson’s disease polyphenols stem cell assays

Infrastructure for collaborative science and societal applications in the Columbia River estuary

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Frontiers of Earth Science 2015年第4期9卷 659-682页

作者： antonio M. BAPTISTA NSF Science and Technology Center for Coastal Margin Observation & Prediction Oregon Health & Science University Portland Oregon 97239 USA Oregon Health & Science University Astoria Oregon 97103 USA Portland State University Portland Oregon 97201 USA Applied Physics Laboratory of the University of Washington Seattle Washington 98105 USA Oregon State University Corvallis Oregon 97331 USA Formerly University of Maryland Center for Environmental Studies Maryland 21613 USA

To meet societal needs, modem estuarine science needs to be interdisciplinary and collaborative, combine discovery with hypotheses testing, and be responsive to issues facing both regional and global stakeholders. Such an approach is best conducted with the benefit of data-rich environments, where information from sensors and models is openly accessible within convenient timeframes. Here, we introduce the operational infrastruc- ture of one such data-rich environment, a collaboratory created to support （a） interdisciplinary research in the Columbia River estuary by the multi-institutional team of investigators of the Science and Technology Center for Coastal Margin Observation ＆ Prediction and （b） the integration of scientific knowledge into regional decision making. Core components of the operational infrastructure are an observation network, a modeling system and a cyber-infrastructure, each of which is described. The observation network is anchored on an extensive array of long-term stations, many of them interdisciplinary, and is complemented by on-demand deployment of temporary stations and mobile platforms, often in coordinated field campaigns. The modeling system is based on finite- element unstructured-grid codes and includes operational and process-oriented simulations of circulation, sediments and ecosystem processes. The flow of information is managed through a dedicated cyber-infrastructure, con- versant with regional and national observing systems.

关键词： estuaries observations numerical modeling,cyber-infrastructure Columbia River

How to deal with right hepatic artery coming from the superior mesenteric artery during minimally invasive pancreaticoduodenectomy: A systematic review

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Hepatobiliary & Pancreatic Diseases International 2023年第2期22卷 121-127页

作者： Andrea Chierici antonio Castaldi Mohamed El Zibawi Edoardo Rosso antonio Iannelli Service de Chirurgie Digestive Centre Hospitalier d’Antibes Juan-les-PinsAntibesFrance Department of Digestive Surgery and Liver Transplantation University Hospital Center of NiceNiceFrance Department of Radiology University Hospital Center of NiceNiceFrance Department of Surgery Centre Hospitalier de LuxembourgLuxembourgLuxembourg Faculty of Medicine UniversitéCôte d’AzurNiceFrance Inserm U1065Team 8’Hepatic Complications of Obesity and Alcohol’NiceFrance

Background: Anatomical variations in the liver arterial supply are quite common and can affect the surgical strategy when performing a minimally invasive pancreaticoduodenectomy(MIPD). Their presence must be preemptively detected to avoid postoperative liver and biliary complications. Data sources: Following the PRISMA guidelines and the Cochrane protocol we conducted a systematic review on the management of an accessory or replaced right hepatic artery(RHA) arising from the superior mesenteric artery when performing an MIPD. Results: Five studies involving 118 patients were included. The most common reported management of the aberrant RHA was conservative(97.0%);however, patients undergoing aberrant RHA division without reconstruction did not develop liver or biliary complications. No differences in postoperative morbidity or long-term oncological related overall survival were reported in all the included studies when comparing MIPD in patients with standard anatomy to those with aberrant RHA. Conclusions: MIPD in patients with aberrant RHA is feasible without increase in morbidity and mortality. As preoperative strategy is crucial, we suggested planning an MIPD with an anomalous RHA focusing on preoperative vascular aberrancy assessment and different strategies to reduce the risk of liver ischemia.

关键词： Pancreatic cancer Pancreaticoduodenectomy Hepatic artery Superior mesenteric artery

Effect of frequency and flexibility ratio on the seismic response of deep tunnels

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Underground Space 2017年第2期2卷 125-133页

作者： Eimar Sandoval antonio Bobet Lyles School of Civil Engineering Purdue UniversityWest Lafayette 47906United States School of Civil Engineering and GeomaticsUniversidad del ValleCaliColombia

Two-dimensional dynamic numerical analyses have been conducted,using FLAC 7.0,to evaluate the seismic response of underground structures located far from the seismic source,placed in either linear-elastic or nonlinear elastoplastic *** interaction between the ground and deep circular tunnels with a tied interface is *** the simulations,it is assumed that the liner remains in its elastic regime,and plane strain conditions apply to any cross section perpendicular to the tunnel *** elastoplastic constitutive model is implemented in FLAC to simulate the nonlinear *** effect of input frequency and relative stiffness between the liner and the ground,on the seismic response of tunnels,is *** response is studied in terms of distortions normalized with respect to those of the free field,and load demand(axial forces and bending moments)in the *** all cases,*** linear-elastic and nonlinear ground models,the results show negligible effect of the input frequency on the distortions of the cross section,for input frequencies smaller than 5 Hz;that is for ratios between the wave length and the tunnel opening(k=D)larger than ten for linear-elastic and nine for nonlinear *** normalized distortions are obtained for the nonlinear than for the linear-elastic ground,for the same relative stiffness,with differences increasing as the tunnel becomes more flexible,or when the amplitude of the dynamic input shear stress *** has been found that normalized distortions for the nonlinear ground do not follow a unique relationship,as it happens for the linear-elastic ground,but increase as the amplitude of the dynamic input *** loading in the liner decreases as the structure becomes more flexible with respect to the ground,and is smaller for a tunnel placed in a stiffer nonlinear ground than in a softer nonlinear ground,for the same flexibility ratio.

关键词： Deep circular tunnel Dynamic numerical analysis Flexibility ratio Distortion Seismic response

Are the number and size of scales in Liolaemus lizards driven by climate?

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Integrative Zoology 2018年第5期13卷 579-594页

作者： María joséTULLI Félix BCRUZ Unidad Ejecutora Lillo(UEL-CONICET) Instituto de HerpetologíaFundación Miguel LilloSan Miguel de TucumánTucumánArgentina Instituto de Investigaciones en Biodiversidad y Medioambiente(INIBIOMA)CONICET-UNCOMA BarilocheRío NegroArgentina

Ectothermic vertebrates are sensitive to thermal fluctuations in the environments where they *** buffer these fluctuations,ectotherms use different strategies,including the integument,which is a barrier that minimizes temperature exchange between the inner body and the surrounding *** lizards,this barrier is constituted by keratinized scales of variable size,shape and texture,and its main function is protection,water loss avoidance and *** size of scales in lizards has been proposed to vary in relation to climatic gradients;however,it has also been observed that in some groups of Iguanian lizards it could be related to ***,here,we studied the area and number of scales(dorsal and ventral)of 60 species of Liolaemus lizards distributed in a broad latitudinal and altitudinal gradient to determine the nature of the variation of the scales with climate,and found that the number and size of scales are related to climatic variables,such as temperature and geographical variables as *** evolutionary process that best explained how these morphological variables evolved was the Ornstein–Uhlenbeck *** number of scales seemed to be related to common ancestry,whereas dorsal and ventral scale areas seemed to vary as a consequence of ecological *** fact,the ventral area is less exposed to climate conditions such as ultraviolet radiation or wind and is,thus,under less pressure to change in response to alterations in external *** is possible that scale ornamentation,such as keels and granulosity,may bring some more information in this regard.

关键词： climate variables habitat use Lioalemidae scale traits

Nanoplasmonic colloidal suspensions for the enhance-ment of the luminescent emission from single-walled carbon nanotubes

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Nano Research 2013年第8期6卷 593-601页

作者： Mareen Glaeske antonio Setaro Department of Physics Freie Universit~t Berlin Amimallee 14 1419S Berlin Germany

Aiming to enhance the luminescence yield of carbon nanotubes, we introduce a new class of hybrid nanoplasmonic colloidal systems （π-hybrids）. Nanotubes dispersed in gold nanorod colloidal suspensions yield hybrid structures exhibiting enhanced luminescence up to a factor of 20. The novelty of the proposed enhancement mechanism relies on including metal proximity effects in addition to its localized surface plasmons. This simple, robust and flexible technique enhances the luminescence of nanotubes with chiralities whose enhancement has never reported before, for example the （8,4） tube.

关键词： carbon nanotubes luminescence enhancement gold nanorods nanoplasmonic colloids hybrid structures

Conductometric Titration for the Prediction of Conductivity in Solutions with Polymeric Membranes

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Journal of Electronic Science and Technology 2017年第4期15卷 342-350页

作者： María josé Lavorante Juan Isidro Franco Research and Development of Renewable Energy Department at CITEDEF Institute of Scientific and Technical Research for the Defense Villa Martelli B1603ALO Argentina

The analytical technique of conductometric titration is used to characterize polymeric *** technique allows obtaining the polymer dry weight capacity(DWC) and the extent of reaction and establishing the optimal number of water molecules per sulfonic *** this particular case the polymer material under study was Nafion?*** different reactions were made: Neutralization and *** of them allow obtaining the same *** titrations could be considered as a good method to study the neutralization and exchange reactions for polymeric materials used in fuel cells or *** implementation of this analytical technique allows reducing operation time of those types of *** waiting time between determinations permits to say that the amount of reactant consumed and products obtained were the same after each addition of titrant.

关键词： Conductivity conductometric titration polymeric membranes