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Imaging Excited-state Dynamics in Two-Dimensional semiconductors with Emerging Ultrafast Measurement Techniques

Accounts of Materials Research 2021年第2期2卷 75-85页

作者： joshua Reding Wei Zhang Jeremy Allam Advanced Technology Institute University of SurreyGuildford GU27XHUnited Kingdom

CONsPECTUs:Two-dimensional halide perovskites(HPs)and monolayer transition metal dichalcogenides(TMDs)are two families of direct band gap semiconductors of particular interest for their unique structural and optoelectronic *** materials confine the motion of charge carriers to a single plane which increases the exciton binding energy,increases the stability of multibody particles,and decreases *** great progress in recent years,the widespread understanding of fundamental properties of these materials is limited by a number of remaining issues including(i)the effects of Rashba splitting and intravalley dynamics on recombination lifetimes;(ii)the effects of passivation of photoinduced and substrate-induced defects on trap state recombination(iii)the contribution of lattice variations and phase transitions on material *** properties influence the material and electronic dynamics on time scales in the range of femtoseconds to nanoseconds,and as such,they require equally fast measurements in order to be *** this perspective,three particular ultrafast pump−probe measurement techniques are highlighted for their ability to provide crucial insights into these unresolved ***-resolved circular dichroism spectroscopy(TRCDs)uses circularly polarized beams to selectively populate and interrogate carriers in spin split valleys,investigate Rashba splitting,and explore valley *** have been mixed results showing Rashba splitting using TRCDs to study pure 2D HPs,though it has successfully shown the splitting in quasi-2D perovskites with an even number of layers and HPs using chiral organic *** monolayer TMDs,it has been used extensively to study spin selective valley dynamics,trion and biexciton dynamics,and now the focus turns to investigating Janus ***-resolved photoemission microscopy uses an ionizing probe beam to eject electrons which are then measured to map defects caused by photoexcitation,subst

关键词： properties. dynamics. splitting

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Light Electrospun Polyvinylpyrrolidone Blanket for Low Frequencies sound Absorption

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Chinese Journal of Polymer science 2018年第12期36卷 1368-1374页

作者： joshua Avossa Francesco Brand Francesco Marulo Giuseppe Petrone stefano Guido Giovanna Tomaiuolo Aniello Costantini Dipartimento di Ingegneria Chimica dei Materiali e della Produzione lndustriale (DICMaPI) Universitgt degli Studi di Napoli Federico II Napoli Italy Dipartimento di lngegneria Industriale (DII) Universita degli Studi di Napoli Federico II Napoli Italy

Light polymeric soundproofing materials （density = 63 kg/m3） of interest for the transportation industry were fabricated through electrospinning. Blankets of electrospun polyvinylpyrrolidone （average fiber diameter = （1.6 ± 0.5） or （2.8 ± 0.5） μm） were obtained by stacking disks of electrospun mats. The sound absorption coefficients were measured using the impedance tube instrument based on AsTM E1050 and IsO 10534-2. For a given set of disks （from a minimum of 6） the sound absorption coefficient changed with the frequency （in the range 200-1600 Hz） following a bell shape curve with a maximum （where the coefficient is greater than 0.9） that shifts to lower frequencies at higher piled disks number and greater fiber diameter. This work showed that electrospinning produced sound absorbers with reduced thickness （2-3 cm） and excellent sound-absorption properties in the low and medium frequency range.

关键词： Electrospinning Polyvinylpyrrolidone (PVP) sound absorption Impedance tube

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stem cells for spine surgery

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World Journal of stem Cells 2015年第1期7卷 186-194页

作者： joshua schroeder Janina Kueper Kaplan Leon Meir Liebergall Department of Orthopedic surgery Spine Surgery Hadassah Medical Center Kiryat Hadassah Jerusalem 91120 Israel Department of Orthopedic surgery Spine and Scoliosis Service Hospital for Special Surgery Weill Cornell Medical College New York NY 10021 United States

In the past few years, stem cells have become the focus of research by regenerative medicine professionals and tissue engineers. Embryonic stem cells, although capable of differentiating into cell lineages of all three germ layers, are limited in their utilization due to ethical issues. In contrast, the autologous harvest and subsequent transplantation of adult stem cells from bone marrow, adipose tissue or blood have been experimentally utilized in the treatment of a wide variety of diseases ranging from myocardial infarction to Alzheimer's disease. The physiologic consequences of stem cell transplantation and its impact on functional recovery have been studied in countless animal models and select clinical trials. Unfortunately, the bench to bedside translation of this research has been slow. Nonetheless, stem cell therapy has received the attention of spinal surgeons due to its potential benefits in the treatment of neural damage, muscle trauma, disk degeneration and its potential contribution to bone fusion.

关键词： Fetal kidney stem cells Mesenchymal and renal progenitor markers Acute renal failure stem cell therapy Angiogenesis

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Planetary defense mission concepts for disrupting/pulverizing hazardous asteroids with short warning time

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Astrodynamics 2017年第1期1卷 3-21页

作者： Bong Wie Ben Zimmerman joshua Lyzhoft George Vardaxis Department of Aerospace Engineering Iowa State UniversityAmesIowa 50011USA

This paper presents an overview of space mission concepts for disrupting or pulverizing hazardous asteroids, especially with warning time shorter than approximately 10 years. An innovative mission concept, referred to as a nuclear hypervelocity asteroid intercept vehicle (HAIV) system, employs both a kinetic-energy impactor and nuclear explosive devices. A new mission concept of exploiting a multiple kinetic-energy impactor vehicle (MKIV) system that doesn’t employ nuclear explosives is proposed in this paper, especially for asteroids smaller than approximately 150 m in diameter. The multiple shock wave interaction effect on disrupting or pulverizing a small asteroid is discussed using hydrodynamic simulation results. A multi-target terminal guidance problem and a planetary defense mission design employing a heavy-lift launch vehicle are also brie y discussed in support of the new non-nuclear MKIV mission concept. The nuclear HAIV and non-nuclear MKIV systems complement to each other to effectively mitigate the various asteroid impact threats with short warning time.

关键词： planetary defense kinetic-energy impactor(KEI) asteroid disruption terminal intercept guidance heavy-lift launch vehicles(HLLV)

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An epigenetic perspective on the failing heart and pluripotent-derived-cardiomyocytes for cell replacement therapy

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Frontiers in Biology 2015年第1期10卷 11-27页

作者： joshua D. TOMPKINs Arthur D. RIGGs Department of Diabetes and Metabolic Disease Research Beckman Research Institute/City of Hope National Medical Center 1500 E DuarteRoad Duarte CA 91010 USA

As life expectancy rises, the prevalence of heart failure is steadily increasing, while donors for organ transplantation remain in short supply （Zwi-Dantsis and Gepstein, 2012）. Indeed, myocardial infarction represents the foremost cause of death within industrialized nations （Henning, 2011） and further, approximately 1% of all newborns harbor a congenital heart defect. Although medical interventions allow 〉 80% of those with cardiac defects to survive to adulthood, there are often extreme emotional and financial burdens that accompany such congenital anomalies, and many individuals will remain at a heightened risk for myocardial infarction throughout the remainder of their lives （Verheugt et al., 2010; Amianto et al., 2011）. In this review, we will discuss the nature of the failing heart and strategies for repair from an epigenetic standpoint. significant focus will reside on pluripotent-to-cardiomyocyte differentiation for cell replacement, epigenetic mechanisms of cardiomyocyte differentiation, epigenetic ＂memories,＂ and epigenetic control of cardiomyocyte cell fate toward translational utility.

关键词： heart failure pluripotent cardiomyocytes epigenetics DNA methylation lncRNA

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Assessing progression of keratoconus: novel tomographic determinants

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Eye and Vision 2016年第1期3卷 49-57页

作者： joshua K.Duncan Michael W.Belin Mark Borgstrom Department of Ophthalmology&Vision science University of ArizonaTucsonAZUSA University of Arizona University Information Technology ServicesTucsonAZUSA

several methods have been described in the literature to both evaluate and document progression in keratoconus,but there is no consistent or clear definition of ectasia *** authors describe how modern corneal tomography,including both anterior and posterior elevation and pachymetric data can be used to screen for ectatic progression,and how software programs such as the Enhanced Reference surface and the Belin-Ambrosio Enhanced Ectasia Display(BAD)can be employed to detect earlier ***,in order to describe specific quantitative values that can be used as progression determinants,the normal noise measurement of the three parameters(corneal thickness at the thinnest point,anterior and posterior radius of curvature(ARC,PRC)taken from the 3.0 mm optical zone centered on the thinnest point),was *** values were obtained by imaging five normal patients using three different technicians on three separate *** 95%and 80%one-sided confidence intervals for all three parameters were surprisingly small(7.88/4.03μm for corneal thickness,0.024/0.012 mm for ARC,and 0.083/0.042 mm for PRC),suggesting that they may perform well as progression determinants.

关键词： Keratoconus Tomography Ectatic disease Progression Amsler-Krumeich scheimpflug Collagen cross-linking

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An analysis of key process parameters for hybrid manufacturing by material extrusion and CNC machining

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Bio-Design and Manufacturing 2018年第4期1卷 237-244页

作者： Ruben Paz Javier santamarta Mario D.Monzon joshua Garcfa Eujin Pei Departamento de Ingenierfa Mecainica Universidad de Las Palmas de Gran CanariaLas Palmas de Gran Canaria 35017 Spain Institute of Materials and Manufacturing Brunel University LondonKingston LaneUxbridge UB83PHUK

Hybrid Manufacturing combines the advantages of Additive Manufacturing (AM)and subtractive Manufacturing on a single *** previous research has provided a good background of the manufacturing parameters,the analysis is often carried out separately and there is a lack of combined *** purpose of this research is to examine the influence of the main manufacturing parameters involved in AM and subtracfive processes using different ***,the study is focused on the Material Extrusion process concerning the layer height,fill angle and fill density;as well as two factors related to machining,including stepover and pass *** parameters that were examined include the dimension,hardness, flatness,weight and roughness.A mulfifactofial Design of Experiments was proposed with a total of 64 ***,a statistical analysis was carried out to assess the influence of the different groups on the response ***,a decision table presented and facilitated the selection of parameters depending on the desired objectives,leading to a framework that was applied to a case study for *** decision guide could enable designers and engineers to select the best strategy for a specific application,leading to a more efficient approach for manufacturing.

关键词： Hybrid manufacturing Material extrusion Additive manufacturing subtractive manufacturing ~Machining statistical analysis

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Nano-bio interfaces probed by advanced optical spectroscopy:From model system studies to optical biosensors

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Chinese science Bulletin 2013年第21期58卷 2537-2556页

作者： ZHANG XiaoXian HAN XiaoFeng WU FuGen JAsENsKY joshua CHEN Zhan Department of Chemistry University of Michigan 930 North University Avenue Ann Arbor

Research in biology and medicine is a rapidly expanding field incorporating some of the most fundamental questions concerning structure, function, and purpose. The forefront of new research demands access to advanced techniques and instrumentation capable of probing these unanswered questions. Over the past several decades, nano-scale materials and devices ranging from quasione dimensional quantum dots to two dimensional graphene sheets have been engineered and have found applications in nano-bio imaging and spectroscopy. In this review, the incorporation of nanomaterials into three influential spectroscopic and microscopic techniques including fluorescence microscopy, surface plasmon resonance, and sum frequency generation will be introduced. Fluorescence imaging has visualized nanomaterials as compliments or replacements to comparable organic fluorphores, act as a quencher for FRET-based sensing, and serve as a nanoscaffold for molecular beacons. Their versatility in coating materials makes nanomaterials an excellent targeting molecule for any cellular macromolecule or structure. In addition to the targeting capabilities of nanomaterials in fluorescence imaging, surface plasmon resonance has incorporated nanomaterials for applications in signal enhancement, selectivity of target molecules, and the development of more refined and accurate detection. Functionalized nano-particles enhance the capabilities of sum frequency generation vibrational spectroscopy by providing unique surface chemistry which alters target molecule interactions and orientations. In summary, the incorporation of nanomaterials has greatly enhanced the field of biology and medicine and has allowed for the continual advancement of not only research but instrument development.

关键词：纳米尺度模型系统生物界面探测表面等离子体共振和频振动光谱纳米材料光学

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Feature-reduction and semi-simulated data in functional connectivity-based cortical parcellation

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Neuroscience Bulletin 2013年第3期29卷 333-347页

作者： Xiaoguang Tian Cirong Liu Tianzi Jiang joshua Rizak Yuanye Ma Xintian Hu Kunming Institute of Zoology Chinese Academy of Sciences The University of Queensland Queensland Brain Institute LIAMA Center for Computational Medicine National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Yunnan Key Lab of Primate Biomedical Research state Key Laboratory of Brain and Cognitive science Institute of Biophysics Chinese Academy of Sciences Kunming Bio-International

Recently, restingstate functional magnetic resonance imaging has been used to parcellate the brain into functionally distinct regions based on the information available in functional connectivity maps. However, brain voxels are not independent units and adjacent voxels are always highly correlated, so functional connectivity maps contain redundant information, which not only impairs the computational efficiency during clustering, but also reduces the accuracy of clustering results. The aim of this study was to propose featurereduction approaches to reduce the redundancy and to develop semisimulated data with defined ground truth to evaluate these approaches. We proposed a featurereduction approach based on the Affinity Propagation Algorithm （APA） and compared it with the classic feature reduction approach based on Principal Component Analysis （PCA）. We tested the two approaches to the parcellation of both semisimulated and real seed regions using the Kmeans algorithm and designed two experiments to evaluate their noise resistance. We found that all functional connectivitymaps （with/without feature reduction） provided correct information for the parcellation of the semi simulated seed region and the computational efficiency was greatly improved by both feature reduction approaches. Meanwhile, the APAbased featurereduction approach outperformed the PCA based approach in noiseresistance. The results suggested that functional connectivity maps can provide correct information for cortical parcellation, and featurereduction does not significantly change the information. Considering the improvement in computational efficiency and the noiseresistance, featurereduction of functional connectivity maps before cortical parcellation is both feasible and necessary.

关键词： cortical parcellation resting-state fMRI functional connectivity feature reduction stimulateddata AP algorithm

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Understanding the medial ulnar collateral ligament of the elbow: Review of native ligament anatomy and function

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World Journal of Orthopedics 2018年第6期9卷 78-84页

作者： joshua R Labott William R Aibinder joshua s Dines Christopher L Camp Mayo Clinic school of Medicine Mayo Clinic Department of Orthopedic surgery Mayo Clinic sports Medicine and shoulder service Hospital of Special Surgery Department of Orthopedic surgery and sports Medicine Mayo Clinic

The medial ulnar collateral ligament complex of the elbow, which is comprised of the anterior bundle [AB, more formally referred to as the medial ulnar collateral ligament(MUCL)], posterior(PB), and transverse ligament, is commonly injured in overhead throwing athletes. Attenuation or rupture of the ligament results in valgus instability with variable clinical presentations. The AB or MUCL is the strongest component of the ligamentous complex and the primary restraint to valgus stress. It is also composed of two separate bands(anterior and posterior) that provide reciprocal function with the anterior band tight in extension, and the posterior band tight in flexion. In individuals who fail co-mprehensive non-operative treatment, surgical repair or reconstruction of the MUCL is commonly required to restore elbow function and stability. A comprehensive understanding of the anatomy and biomechanical properties of the MUCL is imperative to optimize reconstructive efforts, and to enhance clinical and radiographic outcomes. Our understanding of the native anatomy and biomechanics of the MUCL has evolved over time. The precise locations of the origin and insertion footprint centers guide surgeons in proper graft placement with relation to bony anatomic landmarks. In recent studies, the ulnar insertion of the MUCL is described as larger than previously thought, with the center of the footprint at varying distances relative to the ulnar ridge, joint line, or sublime tubercle. The purpose of this review is to consolidate and summarize the existing literature regarding the native anatomy, biomechanical, and clinical significance of the entire medial ulnar collateral ligament complex, including the MUCL(AB), PB, and transverse ligament.

关键词： Elbow Anterior bundle Medial ulnar collateral ligament Native anatomy Biomechanics Valgus stability

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