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Demonstration of Covalent Sidewall Functionalization of Single Wall Carbon Nanotubes by NMR Spectroscopy:Side Chain Length Dependence on the Observation of the Sidewall sp^(3)Carbons

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Nano Research 2008年第1期1卷 72-88页

作者： Liling Zeng lawrence b.alemany Christopher L.Edwards Andrew R.barron Richard E.Smalley Institute for Nanoscale Science and Technology and Department of Chemistry Rice UniversityHoustonTX 77005USA

Carboxylic acid-functionalized single walled carbon nanotubes(SWNTs)prepared via the reaction of an amino acid,NH2(CH2)nCO2H where n=1(glycine,GLY),5(6-aminohexanoic acid,AHA),10(11-aminoundecanoic acid,AUDA),with fl uorinated single walled carbon nanotubes(F-SWNTs)have been characterized by MAS 13C NMR *** ease of observing the aliphatic CH2 groups and the resolution of the signal are dependent on the length of the amino acid’s aliphatic *** have proposed that where substituent chains are short(making NMR data collection difficult)chemical modification to extend the chain length should alleviate analysis *** this regard,we have investigated the esterifi cation of the carboxylic acid *** amino acid-functionalized SWNTs were esterified with an appropriate alcohol to ensure parity of the overall substituent length,i.e.,GLY-SWNT(C1)+1-dodecanol(C_(12))=DOD-GLY-SWNT(1),AHA-SWNT(C_(5))+1-octanol(C_(8))=OCT-AHA-SWNT(2),and AUDA-SWNT(C_(10))+1-propanol(C_(3))=PRO-AUDA-SWNT(3).The 13C NMR shift for the sp3 nitrogen-substituted carbon atoms of the SWNT sidewall is observed atδ≈75 *** the length of SWNT sidewall functional groups enhances the ability to observe the sidewall sp^(3)*** methylene carbon signal intensity is less attenuated in the dipolar dephasing spectrum of the ester-functionalized SWNTs than their associated amino acid derivatives,suggesting more motional freedom of the side chain in the solid *** confi rmation of the dipolar dephasing spectral effects was assisted by the characterization of the ester of AUDA-SWNT with 1,3-propanediol:PPD-AUDA-SWNT(4).

关键词： Single walled carbon nanotube(SWNT) nuclear magnetic resonance(NMR) esterification amino acid functionalization

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A Neuro-Muscular Elasto-Dynamic Model of the Human Arm Part 2:Musculotendon Dynamics and Related Stress Effects

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Journal of bionic Engineering 2009年第2期6卷 108-119页

作者： Cody b.Moody Alan A.barhorst lawrence Schovanec Texas Tech University Department of Mechanical Engineering Texas Tech University Department of Mathematics and Statistics

In this paper we develop an elasto-dynamic model of the human arm that includes effects of neuro-muscular control upon elastic deformation in the *** elasto-dynamic model of the arm is based on hybrid parameter multiple body system variational projection principles presented in the companion *** the technique is suitable for detailed bone and joint modeling,we present simulations for simplified geometry of the bones,discretized as Rayleigh beams with elongation,while allowing for large *** of the upper extremity is simulated by incorporating muscle forces derived from a Hill-type model of musculotendon *** effects of muscle force are modeled in two *** one approach,an effective joint torque is calculated by multiplying the muscle force by a joint moment ann.A second approach models the muscle as acting along a straight line between the origin and insertion sites of the *** arm motion is simulated by utilizing neural feedback and feedforward *** illustrate the combined effects of neural control strategies, models of muscle force inclusion,and elastic assumptions on joint trajectories and stress and strain development in the bone and tendon.

关键词： elasto-dynamics hybrid parameter system musculo skeletal model neuro-muscular model

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Germination and ultrafiltration modify the composition and functional properties of hemp seed protein isolates

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FOOD bIOSCIENCE 2023年第3期53卷 2419-2426页

作者： Liu, Martin Smart, lawrence b. Abbaspourrad, Alireza Cornell Univ Coll Agr & Life Sci Dept Food Sci Ithaca NY 14850 USA Cornell Univ Sch Integrat Plant Sci Hort Sect Cornell AgriTech Geneva NY 14456 USA

Ultrafiltration was investigated for its ability to alter the composition of hemp seed protein isolates (HSPI) and modify its functional properties. Hemp seeds that were germinated for 0, 1, 3, and 5 days underwent alkaline extraction and protein isolation by isoelectric precipitation (IP) or ultrafiltration (UF). UF processing with a 100 nm membrane resulted in the loss of off-color pigments as well as vicilin proteins and small peptides similar to 9 kDa, which changed the physicochemical properties and functionality of HSPI. We found that HSPIs from UF were lighter in color and higher in protein purity than isolates from IP, but lower in solubility. Germination paired with UF increased the water holding capacity by 2.3 times, from 1.06 to 2.46 g water/g isolate, while oil holding capacity was unaffected by germination and UF. UF resulted in protein isolates with decreased foaming capacity and increased gelation concentration compared to IP, but 5-day germinated HSPIs had statistically unchanged emulsifying activity indexes between the two processing methods. Germination and UF are thus presented as clean-label processing techniques to modify the composition and functionality of HSPIs.

关键词： Hemp seed protein Germination Ultrafiltration Functionality Plant protein Ingredients

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Integrating the Climate Science Modelling Language with geospatial software and services

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International Journal of Digital Earth 2009年第S01期2卷 29-39页

作者： D.Lowe A.Woolf b.lawrence S.Pascoe Rutherford Appleton Laboratory British Atmospheric Data CentreDidcotUK Rutherford Appleton Laboratory STFC e-Science CentreDidcotUK

Much consideration is rightly given to the design of metadata models to describe *** the other end of the data-delivery spectrum much thought has also been given to the design of geospatial delivery interfaces such as the Open Geospatial Consortium standards,Web Coverage Service(WCS),Web Map Server and Web Feature Service(WFS).Our recent experience with the Climate Science Modelling Language shows that an implementation gap exists where many challenges remain *** bridge this gap requires transposing information and data from one world view of geospatial climate data to *** of the issues include:the loss of information in mapping to a common information model,the need to create‘views’onto file-based storage,and the need to map onto an appropriate delivery interface(as with the choice between WFS and WCS for feature types with coverage-valued properties).Here we summarise the approaches we have taken in facing up to these problems.

关键词： climate modelling schema standards data interoperability

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New Identities for Weak KAM Theory(For Haim brezis,in continuing admiration)

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Chinese Annals of Mathematics,Series b 2017年第2期38卷 379-392页

作者： lawrence Craig EVANS Department of Mathematics University of CaliforniaBerkeleyUSA.

This paper records for the Hamiltonian H =1/2|p|~2+ W(x) some old and new identities relevant for the PDE/variational approach to weak KAM theory.

关键词： Weak KAM theory, Effective Hamiltonian, Hamiltonian dynamics

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Stress and immunological response of heifers divergently ranked for residual feed intake following an adrenocorticotropic hormone challenge

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Journal of Animal Science and biotechnology 2018年第1期9卷 111-118页

作者： A.K.Kelly P.lawrence b.Earley D.A.Kenny M.McGee School of Agriculture and Food Science College of Health and Agricultural SciencesUniversity College Dublin Livestock Systems Research Department Teagasc Animal&Grassland Research and Innovation CentreGrangeDunsanyCo. Animal and bioscience Research Department Animal&Grassland Research and Innovation CentreTeagascDunsanyCo.

background： When an animal is exposed to a stressor, metabolic rate, energy consumption and utilisation increase primarily through activation of the hypothalamic-pituitary-adrenal（HPA） axis. Changes to partitioning of energy by an animal are likely to influence the efficiency with which it is utilised. Therefore, this study aimed to determine the physiological stress response to an exogenous adrenocorticotropic hormone（ACTH） challenge in beef heifers divergently ranked on phenotypic residual feed intake（RFI）.Results： Data were collected on 34 Simmental weaning beef heifers the progeny of a well characterized and divergently bred RFI suckler beef herd. Residual feed intake was determined on each animal during the postweaning stage over a 91-day feed intake measurement period during which they were individually offered adlibitum grass silage and 2 kg of concentrate per head once daily. The 12 highest [0.34 kg DM/d] and 12 lowest[-0.48 kg DM/d] ranking animals on RFI were selected for use in this study. For the physiological stress challenge heifers（mean age 605 ± 13 d; mean bW 518 ± 31.4 kg） were fitted aseptically with indwelling jugular catheters to facilitate intensive blood collection. The response of the adrenal cortex to a standardised dose of ACTH（1.98 IU/kg metabolic bW^（0.75）） was examined. Serial blood samples were analysed for plasma cortisol, ACTH and haematology variables. Heifers differing in RFI did not differ（P = 0.59） in ACTH concentrations. Concentration of ACTH peaked（P 〈 0.001） in both RFI groups at 20 min post-ACTH administration, following which concentration declined to baseline levels by 150 min. Similarly, cortisol systemic profile peaked at 60 min and concentrations remained continuously elevated for 150 min. A RFI × time interaction was detected for cortisol concentrations（P = 0.06） with high RFI heifers had a greater cortisol response than Low RFI from 40 min to 150 min relative to ACTH administration. Cortisol response was positively assoc

关键词： beef cattle Cortisol Feed efficiency Residual feed intake Stress response

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Precise dating of abrupt shifts in the Asian Monsoon during the last deglaciation based on stalagmite data from Yamen Cave, Guizhou Province, China

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Science China Earth Sciences 2010年第5期53卷 633-641页

作者： EDWARDS R. lawrence Department of Geology and Geophysics University of Minnesota

based on 33 U/Th dates and 1020 oxygen isotopic data from stalagmite Y1 from Yamen Cave, Guizhou Province, China, a record of the Asian Summer Monsoon (ASM) was established. The record covers the last deglaciation and the early Holocene (from 16.2 to 7.3 ka bP) with an average oxygen isotope resolution of 9 years. The main millennial-scale deglacial events first identified in Greenland (Greenland Interstadial Events: GIS 1e through GIS 1a) and later in China are clearly present in the Y1 record. by analogy to earlier work, we refer to these as Chinese Interstadials (CIS): CIS A.1e to CIS A.1a. The onset of these events in Y1 δ18O records are nominally dated at: 14750±50, 14100±60, 13870±80, 13370±80, and 12990±80 a bP. The end of CIS A.1a or the beginning of the Younger Dryas (YD) event is nominally at 12850±50 a bP and the end of the YD dates to 11500±40 a bP. The δ18O values shift by close to 3‰ during the transition into the bφlling-Allerφd (bA, the onset of CIS A.1e) and at the end of the YD. Comparisons of Y1 to previously published early Holocene records show no significant phase differences. Thus, the East Asia Monsoon and the Indian Monsoon do not appear to have been out of phase during this interval. The Y1 record confirms earlier work that suggested that solar insolation and North Atlantic climate both affect the Asian Monsoon.

关键词： stalagmite Asian Monsoon the last deglaciation Holocene U-series dating Yamen Cave

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Interplay : the process of interpersonal communication / Ronald b. Adler, lawrence b. Rosenfeld, Neil Towne ; Russell R. Proctor, II, consulting editor.

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1998年

作者： Ronald b. Adler lawrence b. Rosenfeld Neil Towne Russell R. Proctor II consulting editor.

来源：畅想之星图书光盘版（南... 评论

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Microstructure and mechanical properties of Ti-6Al-4V-5% hydroxyapatite composite fabricated using electron beam powder bed fusion

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Journal of Materials Science & Technology 2019年第2期35卷 309-321页

作者： César A.Terrazas lawrence E.Murr Diego bermudez Edel Arrieta David A.Roberson Ryan b.Wicker W.M.Keck Center for 3D Innovation The University of Texas at El PasoEl PasoTX 79968USA Department of Mechanical Engineering The University of Texas at El PasoTX 79968USA Department of Metallurgical Materials and Biomedical EngineeringThe University of Texas at El PasoTX 79968USA

A novel, Ti-6 Al-4 V(Ti64)/Hydroxyapatite(HA at 5% by weight concentration) metal/ceramic composite has been fabricated using electron beam powder bed fusion(EPbF) additive manufacturing(AM): specifically, the commercial electron beam melting(EbM?) process. In addition to solid Ti64 and Ti64/5% HA samples, four different unit cell(model) open-cellular mesh structures for the Ti64/5% HA composite were fabricated having densities ranging from 0.68 to 1.12 g/cm^3, and corresponding Young's moduli ranging from 2.9 to 8.0 GPa, and compressive strengths ranging from ~3 to 11 MPa. The solid Ti64/5%HA composite exhibited an optimal tensile strength of 123 MPa, and elongation of 5.5% in contrast to a maximum compressive strength of 875 MPa. both the solid composite and mesh samples deformed primarily by brittle deformation, with the mesh samples exhibiting erratic, brittle crushing. Solid, EPbF-fabricated Ti64 samples had a Vickers microindentation hardness of 4.1 GPa while the Ti64/5%HA solid composite exhibited a Vickers microindentation hardness of 6.8 GPa. The lowest density Ti64/5%HA composite mesh strut sections had a Vickers microindentation hardness of 7.1 GPa. Optical metallography(OM) and scanning electron microscopy(SEM) analysis showed the HA dispersoids to be highly segregated along domain or grain boundaries, but homogeneously distributed along alpha(hcp) platelet boundaries within these domains in the Ti64 matrix for both the solid and mesh composites. The alpha platelet width varied from ~5 μm in the EPbF-fabricated Ti64 to ~1.1 m for the Ti64/5%HA mesh strut. The precursor HA powder diameter averaged 5 μm, in contrast to the dispersed HA particle diameters in the Ti64/5%HA composite which averaged 0.5 m. This work highlights the use of EPbF AM as a novel process for fabrication of a true composite structure, consisting of a Ti64 matrix and interspersed and exposed HA domains, which to the authors' knowledge has not been reported before. The results also illu

关键词： Hydroxyapatite (HA) Metal-matrix ceramic composites Open-cellular (mesh) structures Electron-beam powder bed fusion (EPbF) Additive manufacturing (AM) Mechanical properties Microstructure characterization

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Current issues in endoscope reprocessing and infection control during gastrointestinal endoscopy

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World Journal of Gastroenterology 2006年第25期12卷 3953-3964页

作者： Douglas b Nelson lawrence F Muscarella Staff Physician in Gastroenterology Minneapolis VA Medical Center University of MinnesotaMinneapolisMN 55417United States Director Research and Development ChiefInfection ControlCustom UltrasonicsInc

The purpose of this article is to review the evidence regarding transmission of infection during gastrointestinal endoscopy, factors important in endoscope reprocessing and infection control, areas to focus on to impr... 详细信息

关键词： Endoscopy Infection Disinfection Reprocessing Infection control

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