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https://www.readbyqxmd.com/read/28454043/vacuum-scanning-capillary-photoemission-microscopy
#1
S A Aseyev, A P Cherkun, B N Mironov, V V Petrunin, S V Chekalin
We demonstrate the use of a conical capillary in a scanning probe microscopy for surface analysis. The probe can measure photoemission from a substrate by transmitting photoelectrons along the capillary as a function of probe position. The technique is demonstrated on a model substrate consisting of a gold reflecting layer on a compact disc which has been illuminated by an unfocused laser beam with a wavelength 400nm, from a femtosecond laser with a beam size of 4mm. A quartz capillary with a 2-µm aperture has been used in the experiments...
April 19, 2017: Ultramicroscopy
https://www.readbyqxmd.com/read/28453982/effect-of-microstructure-and-surface-hydroxyls-on-the-catalytic-activity-of-au-alooh-for-formaldehyde-removal-at-room-temperature
#2
Zhaoxiong Yan, Zhihua Xu, Jiaguo Yu, Mietek Jaroniec
A series of Au/AlOOH catalysts was prepared by impregnating different AlOOH supports with Au precursor followed by NaBH4-assisted reduction, and examined their activity toward oxidation of indoor formaldehyde (HCHO) pollutant at room temperature. The AlOOH supports used were synthesized by microemulsion, microwave and hydrothermal methods. Among these supports the catalyst obtained by deposition of Au nanoparticles (NPs) on AlOOH prepared by microemulsion method (Au/AlOOH-m) exhibited the highest catalytic activity...
April 19, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28449132/sex-and-diffusion-tensor-imaging-of-white-matter-in-schizophrenia-a-systematic-review-plus-meta-analysis-of-the-corpus-callosum
#3
Saba Shahab, Laura Stefanik, George Foussias, Meng-Chuan Lai, Kelly K Anderson, Aristotle N Voineskos
Sex is considered an understudied variable in health research. Schizophrenia is a brain disorder with known sex differences in epidemiology and clinical presentation. We systematically reviewed the literature for sex-based differences of diffusion properties of white matter tracts in schizophrenia. We then conducted a meta-analysis examining sex-based differences in the genu and splenium of the corpus callosum in schizophrenia. Medline and Embase were searched to identify relevant papers. Studies fulfilling the following criteria were included: (1) included individuals with a diagnosis of schizophrenia, (2) included a control group of healthy individuals, (3) included both sexes in the patient and the control groups, (4) used diffusion tensor imaging, and (5) involved analyzing metrics of white matter microstructural integrity...
April 26, 2017: Schizophrenia Bulletin
https://www.readbyqxmd.com/read/28448817/automated-detection-of-pathologic-white-matter-alterations-in-alzheimer-s-disease-using-combined-diffusivity-and-kurtosis-method
#4
Yuanyuan Chen, Miao Sha, Xin Zhao, Jianguo Ma, Hongyan Ni, Wei Gao, Dong Ming
Diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) are important diffusion MRI techniques for detecting microstructure abnormities in diseases such as Alzheimer's. The advantages of DKI over DTI have been reported generally; however, the indistinct relationship between diffusivity and kurtosis has not been clearly revealed in clinical settings. In this study, we hypothesize that the combination of diffusivity and kurtosis in DKI improves the capacity of DKI to detect Alzheimer's disease compared with diffusivity or kurtosis alone...
April 12, 2017: Psychiatry Research
https://www.readbyqxmd.com/read/28448052/an-in-vitro-organ-culture-model-of-the-murine-intervertebral-disc
#5
Jennifer W Liu, Kevin H Lin, Christian Weber, Sameer Bhalla, Sean Kelso, Kaixi Wang, Simon Y Tang
Intervertebral disc (IVD) degeneration is a significant contributor to low back pain. The IVD is a fibrocartilaginous joint that serves to transmit and dampen loads in the spine. The IVD consists of a proteoglycan-rich nucleus pulposus (NP) and a collagen-rich annulus fibrosis (AF) sandwiched by cartilaginous end-plates. Together with the adjacent vertebrae, the vertebrae-IVD structure forms a functional spine unit (FSU). These microstructures contain unique cell types as well as unique extracellular matrices...
April 11, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28447998/characterization-of-ultra-fine-grained-and-nanocrystalline-materials-using-transmission-kikuchi-diffraction
#6
Gwénaëlle Proust, Patrick Trimby, Sandra Piazolo, Delphine Retraint
One of the challenges in microstructure analysis nowadays resides in the reliable and accurate characterization of ultra-fine grained (UFG) and nanocrystalline materials. The traditional techniques associated with scanning electron microscopy (SEM), such as electron backscatter diffraction (EBSD), do not possess the required spatial resolution due to the large interaction volume between the electrons from the beam and the atoms of the material. Transmission electron microscopy (TEM) has the required spatial resolution...
April 1, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28447997/dielectric-rheosans-simultaneous-interrogation-of-impedance-rheology-and-small-angle-neutron-scattering-of-complex-fluids
#7
Jeffrey J Richards, Cedric V L Gagnon, Jeffery R Krzywon, Norman J Wagner, Paul D Butler
A procedure for the operation of a new dielectric RheoSANS instrument capable of simultaneous interrogation of the electrical, mechanical and microstructural properties of complex fluids is presented. The instrument consists of a Couette geometry contained within a modified forced convection oven mounted on a commercial rheometer. This instrument is available for use on the small angle neutron scattering (SANS) beamlines at the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR)...
April 10, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28447787/designing-dual-emissions-via-co-doping-or-physical-mixing-of-individually-doped-zno-and-their-implications-in-optical-thermometry
#8
Subrata Senapati, Karuna Kar Nanda
Here, we report on the novel design of dual emission via defect state engineering in co-doped oxide microstructures and its implication in fluorescence intensity ratio (FIR) based optical temperature sensing. Eu and Er co-dped ZnO (EuEr:ZnO) microrods prepared by hydrothermal method. The emission peaks corresponding to Eu3+ and Er3+ are observed suggesting dual emission from co-doped ZnO. Interestingly, Er3+ peak intensity decreases and that of Eu3+ increases with increase of temperature as is the case of individual doped cases and dual emission is also achieved via phyical mixing of the individual doped ZnO...
April 27, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28447742/bone-morphogenetic-protein-9-stimulates-callus-formation-in-osteoporotic-rats-during-fracture-healing
#9
Xing Wang, Jun Huang, Fan Huang, Jian-Chun Zong, Xi Tang, Yang Liu, Qiong-Fang Zhang, Yang Wang, Liang Chen, Liang-Jun Yin, Bai-Cheng He, Zhong-Liang Deng
Fracture healing involves the coordinated actions of multiple cytokines. Bone morphogenetic protein 9 (BMP9) is an important factor in bone formation. The present study aimed to investigate the osteogenic potential of bone marrow stem cells (BMSCs) in response to adenoviral (Ad)BMP9, and the early fracture repair properties of AdBMP9 in surgically‑created fractures in osteoporotic rats. Alkaline phosphatase (ALP) activity was assayed and matrix mineralization was examined by Alizarin Red S staining. mRNA and protein expression levels of BMP9, runt‑related transcription factor 2 (RUNX2) and type 1 collagen (COL‑1) were detected in vitro and in vivo...
March 9, 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28447268/atypical-age-dependency-of-executive-function-and-white-matter-microstructure-in-children-and-adolescents-with-autism-spectrum-disorders
#10
Kenia Martínez, Jessica Merchán-Naranjo, Laura Pina-Camacho, Yasser Alemán-Gómez, Leticia Boada, David Fraguas, Carmen Moreno, Celso Arango, Joost Janssen, Mara Parellada
Executive function (EF) performance is associated with measurements of white matter microstructure (WMS) in typical individuals. Impaired EF is a hallmark symptom of autism spectrum disorders (ASD) but it is unclear how impaired EF relates to variability in WMS. Twenty-one male youth (8-18 years) with ASD and without intellectual disability and twenty-one typical male participants (TP) matched for age, intelligence quotient, handedness, race and parental socioeconomic status were recruited. Five EF domains were assessed and several DTI-based measurements of WMS [fractional anisotropy (FA), mean diffusivity (MD) and radial diffusivity (RD)] were estimated for eighteen white matter tracts...
April 26, 2017: European Child & Adolescent Psychiatry
https://www.readbyqxmd.com/read/28447147/diffusion-kurtosis-as-an-in-vivo-imaging-marker-of-early-radiation-induced-changes-in-radiation-induced-temporal-lobe-necrosis-in-nasopharyngeal-carcinoma-patients
#11
Lu Liyan, Wang Si, Wang Qian, Shao Yuhui, Wei Xiaoer, Li Yuehua, Li Wenbin
PURPOSE: Diffusion kurtosis imaging (DKI), an extension of the popular diffusion tensor imaging (DTI) model, has been applied in clinical studies of brain tissue changes. We explored the value of DKI for the early detection of radiation-induced changes in temporal lobe necrosis (TLN) after radiotherapy (RT) for nasopharyngeal carcinoma (NPC). METHODS: A total of 400 patients with NPC were retrospectively enrolled; all participants underwent MRI scans 0-7 days before RT, at 4 weeks during RT, and 1 month after completing RT...
April 26, 2017: Clinical Neuroradiology
https://www.readbyqxmd.com/read/28445995/microstructure-of-spark-plasma-sintered-silicon-nitride-ceramics
#12
O A Lukianova, V Yu Novikov, A A Parkhomenko, V V Sirota, V V Krasilnikov
The microstructure and phase composition of the high-content Al2O3-Y2O3-doped spark plasma-sintered silicon nitride were investigated. Fully dense silicon nitride ceramics with a typical α-Si3N4 equiaxed structure with average grain size from 200 to 530 nm, high elastic modulus of 288 GPa, and high hardness of 2038 HV were spark plasma sintered (SPSed) at 1550 °C. Silicon nitride with elongated β-Si3N4 grains, higher hardness of 1800 HV, density of 3.25 g/cm(3), and Young's modulus 300 GPa SPSed at 1650 °C was also reviewed...
December 2017: Nanoscale Research Letters
https://www.readbyqxmd.com/read/28445645/simultaneous-ni-doping-at-atom-scale-in-ceria-and-assembling-into-well-defined-lotus-like-structure-for-enhanced-catalytic-performance
#13
Qingqing Li, Zhen Huang, Pengfei Guan, Rui Su, Qi Cao, Yimin Chao, Wei Shen, Junjie Guo, Hualong Xu, Renchao Che
Oxide materials with redox capability have attracted worldwide attentions in many applications. Introducing defects into crystal lattice is an effective method to modify and optimize redox capability of oxides as well as their catalytic performance. However, the relationship between intrinsic characteristics of defects and properties of oxides has been rarely reported. Herein, we report a facile strategy to introduce defects by doping a small amount of Ni atoms (1.8 at.%) into ceria lattice at atomic level through the effect of microstructure of crystal on the redox property of ceria...
April 26, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28445276/correlation-between-prefrontal-striatal-pathway-impairment-and-cognitive-impairment-in-patients-with-leukoaraiosis
#14
Shuangkun Wang, Junliang Yuan, Xiaojuan Guo, Leilei Teng, Hua Jiang, Hua Gu, Wenli Hu, Tao Jiang
Our study aimed to investigate the changes of white matter microstructure of cortico-subcortical pathways using diffusion tensor imaging (DTI), and to explore the relationship between abnormal parameters of DTI and cognitive function underlying in patients with leukoaraiosis (LA).A total of 42 patients with LA and 42 age- and sex-matched healthy controls were recruited from Beijing Chaoyang Hospital, Capital Medical University between January 2012 and December 2012. All the subjects underwent scans of conventional magnetic resonance imaging and DTI, and a comprehensive neuropsychological battery was utilized...
April 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28445095/physiological-versus-biological-control-in-bivalve-calcite-prisms-comparison-of-euheterodonts-and-pteriomorphs
#15
Elizabeth M Harper, Antonio Checa
Multiple groups of bivalve molluscs produce calcitic shell layers, many of these broadly classified as "prismatic." Various pteriomorphian bivalves (such as oysters, pterioids, and mussels) secrete prismatic microstructures with high organic content and clear, strong biological control. However, we present the results of a detailed analysis by scanning electron microscopy (SEM), thermogravimetric analysis, and electron backscatter diffraction to characterize the calcitic prisms in two different clades within the euheterodont bivalves: the extant Chama arcana and the extinct rudists...
February 2017: Biological Bulletin
https://www.readbyqxmd.com/read/28444426/investigation-of-altered-microstructure-in-patients-with-drug-refractory-epilepsy-using-diffusion-tensor-imaging
#16
Yuwei Jiang, Lingyan Mao, Xu Yan, Mingxia Fan, Xin Wang, Jing Ding, Dongrong Xu
PURPOSE: The risk of refractory epilepsy can be more dangerous than the adverse effect caused by medical treatment. In this study, we employed voxel-wise analysis (VWA) and tract-based spatial statistics (TBSS) methods to measure microstructural changes using diffusion tensor imaging (DTI) in patients of drug refractory epilepsy (DRE) who had been epileptic for more than 10 years. METHODS: To examine the specific microstructural abnormalities in DRE patients and its difference from medically controlled epilepsy (MCE), we acquired DTI data of 7 DRE patients, 37 MCE patients, and 31 healthy controls (HCs) using a 3 T MRI scanner...
April 25, 2017: Neuroradiology
https://www.readbyqxmd.com/read/28443931/the-effect-of-temperature-composition-and-alcohols-on-the-microstructures-of-catanionic-mixtures-of-sodium-dodecylsulfate-and-cetyltrimethylammonium-bromide-in-water
#17
S Rajkhowa, S Mahiuddin, J Dey, S Kumar, V K Aswal, R Biswas, J Kohlbrecher, K Ismail
The influence of mixing protocol, composition, temperature, ageing and added alcohols on the characteristics of the microstructures of sodium dodecylsulfate (SDS) + cetyltrimethylammonium bromide (CTAB) mixtures has been investigated in this paper. In this catanionic mixture (1 weight% total surfactant content) temperature induced microstructural transition occurs, which is (i) a micelle-to-vesicle transition (MVT) if αSDS (mole fraction of SDS) = 0.7, 0.8 or 0.9 and (ii) a vesicle-to-micelle transition (VMT) if αSDS = 0...
April 26, 2017: Soft Matter
https://www.readbyqxmd.com/read/28443922/friction-lubrication-and-in-situ-mechanics-of-poroelastic-cellulose-hydrogels
#18
G K Dolan, G E Yakubov, M R Bonilla, P Lopez-Sanchez, J R Stokes
The tribology between biphasic materials is challenging to predict and interpret due to the interrelationship between mechanical properties, microstructure and movement of the fluid phase contained within. A new approach is presented to deconvolute these effects for cellulose hydrogels, which have a fibrous network that is akin to the microstructure of articular cartilage and plant cell walls. This is achieved by developing a tribo-rheological technique that uniquely incorporates in situ mechanical characterisation (compression-relaxation and small amplitude oscillatory shear) immediately prior to measuring the tribological response between pairs of hydrogels...
April 26, 2017: Soft Matter
https://www.readbyqxmd.com/read/28443878/influence-of-high-energy-electron-irradiation-on-the-network-structure-of-gelatin-hydrogels-as-investigated-by-small-angle-x-ray-scattering-saxs
#19
Emilia I Wisotzki, Paolo Tempesti, Emiliano Fratini, Stefan G Mayr
The impact of high energy crosslinking on the network structure of gelatin hydrogels was investigated in comparison to physically entangled gels by small-angle X-ray scattering (SAXS). Physically entangled gelatin of increasing concentration exhibited a nearly constant correlation length of several nanometers. These gels had scattering behavior close to that of polymer coils swollen in a good solvent, as evidenced by the Porod exponent of 1.8. The mass fractal dimension decreased towards 1, indicating increased formation of semiflexible gelatin triple helices and rod-like structures as a function of the gelatin concentration...
April 26, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28442174/microstructural-alterations-owing-to-handling-of-bovine-pericardium-to-manufacture-bioprosthetic-heart-valves-a-potential-risk-for-cusp-dehiscence
#20
J Mao, Y Wang, E Philippe, T Cianciulli, I Vesely, D How, J-M Bourget, L Germain, Z Zhang, R Guidoin
INTRODUCTION: Cross-linking and anti-calcification of prosthetic heart valves have been continuously improved to prevent degeneration and calcification. However, non-calcific structural deteriorations such as cuspal dehiscences along the stent still require further analysis. MATERIAL AND METHOD: Based upon the previous analysis of an explanted valve after 7 years, a fresh commercial aortic valve was embedded in poly(methyl methacrylate) (PMMA) and cut into slices to ensure the detailed observation of the assembly and material structures...
April 22, 2017: Morphologie: Bulletin de L'Association des Anatomistes
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