bluuebunny/crossref_metadata_2025 huggingface dataset:
The cuprizone model: regional heterogeneity of pathology
Authors: Wergeland Stig , Torkildsen Øivind , Myhr Kjell‐Morten , Mørk Sverre Jarl , Bø Lars
Published: February 2012

The cuprizone model is a model of de‐ and remyelination secondary to oligodendrocyte death, likely to be mediated by an inhibition of mitochondrial function. The aim of this study was to characterize histopathological changes associated with de/remyelination in grey and white matter at different disease stages in C57Bl/6 mice after per oral administration of cuprizone. Oligodendrocyte loss, astrocytosis and complement activation was detected in areas of demyelination. Demyelination, astrocytosis and complement activation occurred earlier in the cerebral cortex than in the corpus callosum. There was no perivascular lymphocyte infiltration. Microglia‐ and macrophage activation was observed in the corpus callosum, but not in the cerebral cortex. After cuprizone exposure was stopped, remyelination was extensive in the corpus callosum, but scarce in the cortex. In conclusion, cortical demyelination and oligodendrocyte loss in the cuprizone model may be due to a direct effect on oligodendrocyte mitochondrial function, as it occurs in the absence of microglial activation. The histopathology of de/remyelination in the cuprizone treated mice show regional heterogeneities which suggest differences in the underlying pathophysiology. Cuprizone‐induced demyelination is a relevant model for the study of regional heterogeneity of demyelination and lesion pathology in multiple sclerosis.
Laforin, a protein with many faces: glucan phosphatase, adapter protein, et alii
Authors: Gentry Matthew S. , Romá‐Mateo Carlos , Sanz Pascual
Published: February 2012

Lafora disease (LD) is a rare, fatal neurodegenerative disorder characterized by the accumulation of glycogen‐like inclusions in the cytoplasm of cells from most tissues of affected patients. One hundred years after the first description of these inclusions, the molecular bases underlying the processes involved in LD physiopathology are finally being elucidated. The main cause of the disease is related to the activity of two proteins, the dual‐specificity phosphatase laforin and the E3‐ubiquitin ligase malin, which form a functional complex. Laforin is unique in humans, as it is composed of a carbohydrate‐binding module attached to a cysteine‐based catalytic dual‐specificity phosphatase domain. Laforin directly dephosphorylates glycogen, but other proteinaceous substrates, if they exist, have remained elusive. Recently, an emerging set of laforin‐binding partners apart from malin have been described, suggestive of laforin roles unrelated to its catalytic activity. Further investigations based on different transgenic mouse models have shown that the laforin–malin complex is also involved in other cellular processes, such as response to endoplasmic reticulum stress and misfolded protein clearance by the lysosomal pathway. However, controversial data and some missing links still make it difficult to assess the concrete relationship between glycogen deregulation and neuronal damage leading to the fatal symptoms observed in LD patients, such as myoclonic seizures and epilepsy. Consequently, clinical treatments are far from being achieved. In the present review, we focus on the knowledge of laforin biology, not only as a glucan phosphatase, but also as an adaptor protein involved in several physiological pathways.
IDH Mutation Detection in Formalin‐Fixed Paraffin‐Embedded Gliomas Using Multiplex PCR and Single‐Base Extension
Authors: Perizzolo Marco , Winkfein Bob , Hui Susan , Krulicki Wally , Chan Jennifer A. , Demetrick Douglas J.
Published: February 2012

Isocitrate dehydrogenase (IDH) genes are mutated in a significant portion of gliomas, myeloid leukemias and chondroid neoplasms. In gliomas, IDH mutations are prognostic, as those tumors with the mutation are associated with a proneural subclass and have longer survival compared with those without the mutation. We developed a simple, PCR‐based SNaPshot® assay (Life Technologies, Carlsbad, CA, USA) to detect IDH1/2 mutations. This protocol combines a single, multiplexed PCR reaction using gene specific primers followed by a single, multiplexed SNaPshot reaction and detection by capillary electrophoresis. In a blinded study of 32 paraffin‐embedded glioma specimens previously screened for IDH mutations by a PCR/direct sequencing method, concordance of our IDH SNaPshot test with sequencing was 100%. We performed the assay on an additional 57 specimens submitted for diagnostic IDH mutation evaluation. Data analysis was much faster and easier to perform than analysis of the sequencing data, and results could be obtained in 1 day from DNA extraction to analysis. Furthermore, we could readily identify a mixture of 5% mutant allele vs. 95% wild‐type allele in our SNaPshot assay, in comparison to approximately 20% mutant allele in our PCR‐sequencing assay. Our assay represents a fast, sensitive, straightforward method of reliably detecting common mutations of IDH genes in glial neoplasms, or other tumors.
Philosophy and the practice of Bayesian statistics
Authors: Gelman Andrew , Shalizi Cosma Rohilla
Published: February 2012

A substantial school in the philosophy of science identifies Bayesian inference with inductive inference and even rationality as such, and seems to be strengthened by the rise and practical success of Bayesian statistics. We argue that the most successful forms of Bayesian statistics do not actually support that particular philosophy but rather accord much better with sophisticated forms of hypothetico‐deductivism. We examine the actual role played by prior distributions in Bayesian models, and the crucial aspects of model checking and model revision, which fall outside the scope of Bayesian confirmation theory. We draw on the literature on the consistency of Bayesian updating and also on our experience of applied work in social science. Clarity about these matters should benefit not just philosophy of science, but also statistical practice. At best, the inductivist view has encouraged researchers to fit and compare models without checking them; at worst, theorists have actively discouraged practitioners from performing model checking because it does not fit into their framework.
Film Thickness and Asperity Load Formulas for Line-Contact Elastohydrodynamic Lubrication With Provision for Surface Roughness
Authors: Masjedi M. , Khonsari M. M.
Published: February 2012

Three formulas are derived for predicting the central and the minimum film thickness as well as the asperity load ratio in line-contact EHL with provision for surface roughness. These expressions are based on the simultaneous solution to the modified Reynolds equation and surface deformation with consideration of elastic, plastic and elasto-plastic deformation of the surface asperities. The formulas cover a wide range of input and they are of the form f(W, U, G, σ¯, V), where the parameters represented are dimensionless load, speed, material, surface roughness and hardness, respectively.
Investigation of Cooling Process of a High-Temperature Hollow Cylinder in Moving Induction Heat Treatment
Authors: Shokouhmand H. , Ghaffari S.
Published: February 2012

The hardness of heat treated steel and probability of occurrence of quenching cracks depend on the cooling time and temperature distribution. Therefore, the investigation of cooling process is a crucial issue in heat treatment to evaluate the obtained structure of the work-piece. In the present work, a vertical hollow circular cylinder is heated up to a specific temperature by a moving coil at a given velocity along it, and the heated parts then quenched by a moving water–air spray. After passing the spray, the cylinder is cooled by natural convection with the surrounding air. An analysis of coupled magnetic problem and transient conjugated thermal problem between the solid and the surrounding air is performed using finite-element method to obtain temperature field in each time step. This procedure includes moving boundary conditions, effect of radiation with ambient, temperature-dependent properties, and change in magnetic permeability of specified alloy at the Curie temperature. The obtained results show how both spray and natural cooling affect the temperature distribution and rate of cooling of the cylinder. Furthermore, the effect of geometry and velocity of coil on the rate of cooling and chance of quenching cracks are investigated.
Detailed Heat Transfer Measurements Inside Rotating Ribbed Channels Using the Transient Liquid Crystal Technique
Authors: Lamont Justin A. , Ekkad Srinath V. , Alvin Mary Anne
Published: February 2012

Coolant flow in rotating internal serpentine channels is highly complex due to the effects of the Coriolis force and centrifugal buoyancy. Detailed knowledge of the heat transfer over a surface will greatly enhance the blade designers’ ability to predict hot spots so coolant may be distributed effectively. The present study uses a novel transient liquid crystal technique to measure heat transfer on a rotating two-pass channel surface with chilled inlet air. The present study examines the differences in heat transfer distributions on channel surfaces with smooth walls, 90 deg rib and W-shaped rib turbulated walls. The test section is made up of two passes to model radially inward and outward flows. To account for centrifugal buoyancy, cold air is passed through a room temperature test section. This ensures that buoyancy is acting in a similar direction to real turbine blades. The inlet coolant-to-wall density ratio is fixed at 0.08, Re = 16,000, and Ro = 0.08. The present study shows that the W-shaped ribs enhance heat transfer in all cases (stationary and rotating) approximately 1.75 times more than the 90 deg ribs. The W-shaped rib channel is least affected by rotation, which may be due to the complex nature of the secondary flow generated by the geometry. A higher pressure drop is associated with the W-shaped ribs than the 90 deg ribs, however, the overall thermal-hydraulic performance of the W-shaped ribs still exceeds that set by the 90 deg ribs.
Natural Ventilation in a Model Room
Authors: Subudhi Sudhakar , Sreenivas K. R. , Arakeri Jaywant H.
Published: February 2012

Natural ventilation of a model room with water as the fluid medium is studied. It is insulated by air gaps on the four sides and at the top. A constant heat flux has been maintained on the bottom surface of the room. This room is surrounded by a large exterior tank containing water. There are three openings each on two opposing sides of the model room. For any experiment, only one opening on each side is kept open. Fluid enters or leaves these openings and the flow is driven entirely by buoyancy forces. Shadowgraph technique is used for visualization. The buoyancy causes flow to enter through the bottom opening and leaves through the top opening. At the openings, buoyant jets are observed and which have higher or lower relative density compared with that of its environment. The buoyant jet at the inlet interacts with the plumes on the heated bottom plate. From these visualizations, it appears that free convection at bottom plate will be affected by the buoyant jets at the openings and the degree to which it is affected depends on the position and size of openings and distance between inlet and outlet. The flow rate due to the natural ventilation depends on the bottom surface heat flux and the height difference between the openings. The temperatures of the floor, the interior and the exterior are calculated using a simple mathematical model. The values of temperatures obtained in the experiments are reasonably well predicted by the mathematical model.
Gas Lubrication Analysis Method of Step-Dimpled Face Mechanical Seals
Authors: Bai Shaoxian , Peng Xudong , Li Yefeng , Sheng Songen
Published: February 2012

In solving Reynolds equation with the conventional finite difference method, keeping the flow continuity has ofen been ignored, which will lead to an analysis error in the pressure distribution and leakage rate, especially for discontinuous clearance caused by step structures such as laser surface texturing sealing surfaces. In this paper, a finite difference method is introduced to satisfy the flow continuity to solve the Reynolds equation. Then, the pressure distribution for a typical rectangular step structure is obtained via two different methods: a numerical solution of the exact full Navier-Stokes equations, and a solution of the Reynolds equation solved by the previously mentioned method. A comparison between the two solution methods illustrates that, for both pressure flow and shear flow, the pressure distribution from the new difference method is in good agreement with that from the Navier-Stokes equations, and the new difference method can reflect the characteristic of the pressure sudden-change of the shear flow at the steps. Finally, the pressure distribution and leakage rate of a step-dimpled seal face are acquired with the presented method. The results show that the presented method allows gas-lubricating analysis of mechanical face seals with discontinuous clearance, and can keep the leakage rate continuous in the radial direction.
An Experimental Study on the Effect of Oil Viscosity and Wear-Ring Clearance on the Performance of an Industrial Centrifugal Pump
Authors: Li Wen-Guang
Published: February 2012

The clearance of wear-rings in the impeller of centrifugal pumps has an important influence on the pump’s performance. Unfortunately, this effect has not been quite well documented, especially for the centrifugal pumps handling viscous oils. An industrial centrifugal pump with low specific speed was employed as a model to investigate the effect of the clearance on the performance of the pump. In this experimental study, the clearances of the wear-rings on the impeller shroud and hub were enlarged; the performances of the pump were measured when it pumped water and the viscous oils. The performance curves, the hydraulic parameters, and their relative variation ratios at best efficiency points were examined carefully for different clearances at various viscosities. The results showed that the flow rate is varied relatively in a range of −6% − +5%, the head −10% − +6%, the shaft-power + 2% −+8% and the efficiency −19% − +2%, respectively, when the clearance was enlarged from 0.25 mm to 0.85 mm at best efficiency points. The clearance of wear-rings on shroud has a more significant influence on the performance than on the hub. However, such an effect is weakened with increasing viscosity.
Incompressible Laminar Developing Flow in Microchannels
Authors: Galvis E. , Yarusevych S. , Culham J. R.
Published: February 2012

In many engineering systems, such as compact heat exchangers and microcoolers used in electronics packaging, system performance depends on laminar flow development in microchannels. This study investigates effects of Reynolds number, hydraulic diameter, and channel aspect ratio on the entrance length in rectangular microchannels. Numerical investigations were performed for microchannels with hydraulic diameters between 100 and 500 μm, Reynolds numbers between 0.5 and 200, and channel aspect ratios between 1 and 5. The results show good agreement with available experimental data and are used to formulate new correlations for estimating the entrance length in microchannels. Compared to other correlations, these new correlations are shown to provide more accurate estimates of entrance length over a wider range of Reynolds numbers representative of practical flows in microchannels.
A Rolling Contact Fatigue Reliability Evaluation Method and its Application to a Slewing Bearing
Authors: Hai Gao Xue , Diao Huang Xiao , Jing Hong Rong , Hua Wang , Jie Chen
Published: February 2012

Rolling contact fatigue (RCF) corresponds to the formation of the first spall, which is a stochastic behavior; therefore, the RCF life should be reliably calculated. A method for evaluating RCF reliability was developed based on the Lundberg-Palmgren theory and ISO 281. The method took into consideration the contact load, the geometric parameters of contact pairs, the oscillation amplitude, the RCF reliability and the material properties. Because the method was derived from a widely accepted theory and empirical standards, it can be used for engineering applications. Finally, the RCF reliability of a slewing bearing under complex operating conditions was determined using the developed method.
A Simplified Nonlinear Transient Analysis Method for Gas Bearings
Authors: Hassini M. Amine , Arghir Mihai
Published: February 2012

The traditional small perturbation method is successfully used for linear dynamic analysis of gas bearings but excludes any nonlinear study. Investigating large displacements requires the evaluation of the nonlinear aerodynamic forces in the thin film. To avoid solving the unsteady compressible thin film fluid equations, we propose a method based on the use of frequency dependent dynamic coefficients and on the rational function approximation of the resulting impedances. Calculating impedances for several eccentricities enables mapping the full dynamic behavior of the bearing. A set of ordinary differential equations is then developed by using the inverse of Laplace transform. The equations of motion of the rotor are subsequently solved numerically with local linearization at each time step. The numerical results obtained by using impedances are in good agreement with the reaction forces obtained by solving the full nonlinear transient Reynolds equation.
Procedure to Estimate Thermophysical and Geometrical Parameters of Embedded Cancerous Lesions Using Thermography
Authors: Manuel Luna Jose , Romero-Mendez Ricardo , Hernandez-Guerrero Abel , Elizalde-Blancas Francisco
Published: February 2012

Based on the fact that malignant cancerous lesions (neoplasms) develop high metabolism and use more blood supply than normal tissue, infrared thermography (IR) has become a reliable clinical technique used to indicate noninvasively the presence of cancerous diseases, e.g., skin and breast cancer. However, to diagnose cancerous diseases by IR, the technique requires procedures that explore the relationship between the neoplasm characteristics (size, blood perfusion rate and heat generated) and the resulting temperature distribution on the skin surface. In this research work the dual reciprocity boundary element method (DRBEM) has been coupled with the simulated annealing technique (SA) in a new inverse procedure, which coupled to the IR technique, is capable of estimating simultaneously geometrical and thermophysical parameters of the neoplasm. The method is of an evolutionary type, requiring random initial values for the unknown parameters and no calculations of sensitivities or search directions. In addition, the DRBEM does not require any re-meshing at each proposed solution to solve the bioheat model. The inverse procedure has been tested considering input data for simulated neoplasms of different sizes and positions in relation to the skin surface. The successful estimation of unknown neoplasm parameters validates the idea of using the SA technique and the DRBEM in the estimation of parameters. Other estimation techniques, based on genetic algorithms or sensitivity coefficients, have not been capable of obtaining a solution because the skin surface temperature difference is very small.
Coherent Sensing of a Mechanical Resonator with a Single-Spin Qubit
Authors: Kolkowitz Shimon , Bleszynski Jayich Ania C. , Unterreithmeier Quirin P. , Bennett Steven D. , Rabl Peter , Harris J. G. E. , Lukin Mikhail D.
Published: February 2012

The spin of a nitrogen vacancy defect in diamond is used to sense the motion a magnetized microresonator.
The Role of Driving Energy and Delocalized States for Charge Separation in Organic Semiconductors
Authors: Bakulin Artem A. , Rao Akshay , Pavelyev Vlad G. , van Loosdrecht Paul H. M. , Pshenichnikov Maxim S. , Niedzialek Dorota , Cornil Jérôme , Beljonne David , Friend Richard H.
Published: February 2012

Bands That Separate

In organic photovoltaic devices, the charge carriers that form at the interface between donor and acceptor layers—the electrons and holes—form bound states called excitons. Efficient current generation requires some mechanism for their separation and for the movement of free carriers to the electrodes.

Bakulin
et al.

(p.
1340
, published online 23 February) studied a process in which the excitons created with an optical pulse were also subjected to infrared pulses. In polymer-blend devices, a three-step process was observed: The boundstate excitons diffused toward the donor-acceptor interface, formed a charge-transfer state, and then dissociated into free carriers.
Evaluation of the Vietnamese A6 mortality reporting system: injury as a cause of death
Authors: Stevenson Mark R , Ngoan Le Tran , Hung Dang Viet , Huong Tu Nguyen Thi , Mai Anh Luong , Ivers Rebecca Q , Huong Hoang Thanh
Published: February 2012

Background

Despite the fact that the A6 mortality reporting system has been operating for almost 20 years in Vietnam, there has been no systematic evaluation of the system. This study assesses the completeness, sensitivity and positive predictive value of the system in relation to injury related mortality.

Methods

Evaluation of the A6 system was undertaken in three (geographically distributed) provinces in Vietnam. Deaths identified in the A6 system were compared with deaths identified by an independent consensus panel to determine the per cent completeness of the A6 system. Verbal autopsies (VA) were conducted for all identified deaths from the consensus panels, and the sensitivity and positive predictive value of the A6 system were assessed using the VAs as the reference.

Results

5273 deaths were identified from the A6 system with a further 340 cases identified by the independent consensus panel (total n=5613). Injury related deaths accounted for 13.6% (n=763) of all deaths with an overall injury mortality rate of 55.3 per 100 000 person years. The per cent completeness of the A6 system in relation to injury deaths was 93.9% with a sensitivity of 75.4%, specificity of 98.4% and positive predictive value of 88.4%.

Conclusions

The A6 mortality reporting system is embedded within the commune health system and is the lead mortality reporting system for the Ministry of Health. The system performs well in relation to its completeness and classification of injury related deaths. With further enhancements and ongoing support from government and donor agencies, the A6 system will be a valuable resource for identifying and planning preventive strategies targeting the leading causes of injury related deaths in Vietnam.
A NOVEL LATTICE TRAFFIC FLOW MODEL AND ITS SOLITARY DENSITY WAVES
Authors: ZHU WEN-XING , ZHANG LI-DONG
Published: February 2012

A novel lattice traffic flow model with a slope effect is proposed. Neutral stability condition is obtained by the use of the linear stability theory. The standard KdV equation is derived in the meta-stable region and soliton solution is obtained near the neutral stability line. The solitary waves are reproduced through the numerical simulations. Results show that the solitary density wave appears in upward form when the average density is less than critical density, otherwise it exhibits downward form.
CHARACTERIZATION OF QUANTUM DOTS, SINGLE WALLED CARBON NANOTUBES AND NICKEL OCTADECYLPHTHALOCYANINE CONJUGATES
Authors: KHENE SAMSON , NYOKONG TEBELLO
Published: February 2012

In this work nickel octadecylphthalocyanine (NiPc(C10H21)8) and cadmium telluride quantum dots (QDs) capped with thioglycolic acid (TGA) are adsorbed on single walled carbon nanotubes (SWCNT) to form NiPc(C10H21)8 -SWCNT-QDs conjugate. X-ray photoelectron, ultra violet/visible and Raman spectroscopies are used to characterize the conjugate. SWCNT, poly- Ni(O)Pc(C10H21)8 , NiPc(C10H21)8 -SWCNT and NiPc(C10H21)8 -SWCNT-QDs complexes are used to modify glassy carbon electrode (GCE) and used for the electro-oxidation of pentachlorophenol as a test molecule. NiPc(C10H21)8 -SWCNT-QDs electrode gave the best detection current for pentachlorophenol.
THE LINEAR TIME FREQUENCY ANALYSIS TOOLBOX
Authors: SØNDERGAARD PETER L. , TORRÉSANI BRUNO , BALAZS PETER
Published: February 2012

The Linear Time Frequency Analysis Toolbox is a MATLAB/Octave toolbox for computational time-frequency analysis. It is intended both as an educational and computational tool. The toolbox provides the basic Gabor, Wilson and MDCT transform along with routines for constructing windows (filter prototypes) and routines for manipulating coefficients. It also provides a bunch of demo scripts devoted either to demonstrating the main functions of the toolbox, or to exemplify their use in specific signal processing applications. In this paper we describe the used algorithms, their mathematical background as well as some signal processing applications.
ON THE CONTINUOUS WAVELET TRANSFORM ON HOMOGENEOUS SPACES
Authors: ESMAEELZADEH F. , KAMYABI GOL R. A. , RAISI TOUSI R.
Published: February 2012

Let G be a locally compact group with a compact subgroup H. We define a square integrable representation of a homogeneous space G/H on a Hilbert space [Formula: see text]. The reconstruction formula for G/H is established and as a result it is concluded that the set of admissible vectors is path connected. The continuous wavelet transform on G/H is defined and it is shown that the range of the continuous wavelet transform is a reproducing kernel Hilbert space. Moreover, we obtain a necessary and sufficient condition for the continuous wavelet transform to be onto.
BALANCED INTERPOLATORY MULTIWAVELETS WITH MULTIPLICITY r
Authors: LI BAOBIN , LUO TIEJIAN , PENG LIZHONG
Published: February 2012

Vector-valued refinable interpolatory functions with multiplicity r are discussed in this paper. This kind of refinable functions have a sampling property like Shannon's sampling theorem, and corresponding matrix-valued refinable masks possess special structure. In the context of multiwavelets, some properties of multifilter banks related will be present. Based on these properties, it will be shown that there are no symmetric (or antisymmetric) vector-valued refinable functions with interpolatory property. In the practical application, multiwavelets are always required to possess a certain degree of smoothness, which is related to three different concepts: balancing order, approximation order and analysis-ready order. In the general case, three notions are different. But if the scaling function is interpolatory, three concepts will be verified to equal to each other. Finally, a complete characterization of multifilter banks {H, G} will also be given and it will be used to construct some new balanced multiwavelets with interpolatory property for case r = 2, corresponding to which, multifilter banks have rational coefficients.
Efficient Biopolymer Blue Organic Light-Emitting Devices with Low Driving Voltage
Authors: Chen I-Ching , Chiu Yi-Wen , Hung Yu-Chueh
Published: February 2012

We demonstrate blue organic light-emitting devices (OLEDs) with high luminance based on DNA biopolymer. We incorporated aromatic surfactant in the synthesis of DNA biopolymer, which results in lower operation voltage of biopolymer-based OLEDs and a turn-on voltage of 3.77 V was achieved. Maximum luminance of 12277 cd/m2 and a 46.4% enhancement in luminous efficacy of blue OLED based on DNA biopolymer was demonstrated compared to the reference device. This demonstrates a viable and facile route to adjust the conductivity of DNA biopolymer and paves the way towards multifunctional biomaterial-based optoelectronic devices and applications.
Surface Morphological Effects on Subwavelength Filter of Nanoscale Grating for Near Infrared Biosensing
Authors: Jao Chih-Sheng , Lin Hoang Yan
Published: February 2012

We modeled the effects of surface roughness (SR) on a near-infrared guided-mode resonance (GMR) biosensor. A power spectral density function was used to describe the SR with spatial autocorrelation integration through a rigorous coupled-wave analysis (RCWA), and a peak wavelength value (PWV) shift in reflectance was observed under transverse electric (TE) and transverse magnetic (TM) polarization. Sub-nanometer SR caused significant PWV shifts, leading to invalid spectral recognition. In addition to random roughness, we studied the PWV reflectance shift for SR models such as sinusoidal, rectangular, and effective medium types. All SR models showed a larger PWV shift for TM polarization than for TE polarization. Owing to SR, PWV reflectance decreased abruptly for TM polarization at small angular deviations from normal incidence. However, the symmetrically splitting of the reflectance spectra for TE polarization implied a high angular tolerance to fabrication errors. Compared to vertical sidewall roughness in our prior work, the SR is much more deleterious for GMR biosensing and should be appropriately controlled.
Noninvasive In-vivo Measurements of Microvessels by Reflection-Type Micro Multipoint Laser Doppler Velocimeter
Authors: Ishida Hiroki , Andoh Tsugunobu , Akiguchi Shunsuke , Hachiga Tadashi , Ishizuka Masaru , Shimizu Tadamichi , Shirakawa Hiroki , Kuraishi Yasushi
Published: February 2012

We have developed a micro multipoint laser Doppler velocimeter (µ-MLDV) that enables selective collection of Doppler interference photons. In previous report [H. Ishida et al.: Rev. Sci. Instrum. 82 (2011) 076104], developed the reflection-type µ-MLDV, and showed the results of demonstrations performed on transparent artificial flow channels. In this study, we attempted to perform in-vivo experiments using animals. It can measure absolute velocity and generate tomographs of blood vessels courses. The present system can perform noninvasive in-vivo measurements with a detection limit of about 0.5 mm/s and a spatial resolution in the x–y plane of 125 µm. It is thus able to image venulae. It was used to image venulae in a mouse ear and a subcutaneous blood vessel in a mouse abdomen at a depth of about 1.0 mm below the skin.
Force Mapping of the NaCl(100)/Cu(111) Surface by Atomic Force Microscopy at 78 K
Authors: Li Yan Jun , Kinoshita Yukinori , Tenjin Keita , Ma Zong Min , Kou Li Li , Naitoh Yoshitaka , Kageshima Masami , Sugawara Yasuhiro
Published: February 2012

A new atomic force microscopy (AFM) force mapping technique has been used to investigate insulating thin (100) films of NaCl on conducting Cu(111) substrate at 78 K. This technique was able to map the interaction forces between the AFM tip and the surface ions of the sample. The site-specific force curves of the (100) surface of the NaCl thin films are presented. We observed only an attractive short-range interaction force at the Na+ and Cl- sites. We propose simple models to explain the behavior of the force curves at the different ion sites.
Self-Assembled Growth of Spinel (Fe,Zn)3O4–Perovskite BiFeO3 Nanocomposite Structures Using Pulsed Laser Deposition
Authors: Sakamoto Takuya , Hattori Azusa N. , Kanki Teruo , Hattori Ken , Daimon Hiroshi , Akinaga Hiroyuki , Tanaka Hidekazu
Published: February 2012

Nanocomposite thin films consisting of spinel-type magnetic semiconductor (Fe,Zn)3O4 and perovskite-type ferroelectric BiFeO3 were prepared by a self-assembled growth method from a composition-adjusted Fe–Zn–Bi–O single target using a pulsed laser deposition technique. It is found that BiFeO3 square patterns reflecting the in-plane lattice shape of the SrTiO3 substrate are grown directly from the substrate interface with inverse pyramid shapes embedded in a (Fe,Zn)3O4 matrix in the absence of other phases. This self-assembled growth should be a convenient method to fabricate a lot of nano-heterojunctions with complicated oxide structures, which is applicable to spintronic oxide materials.
Nucleation and Crystal Growth of Si1-xGex Melts during Rapid Cooling Processes: A Molecular-Dynamics Study
Authors: Xiao Yanping , Taguchi Jun , Motooka Teruaki , Munetoh Shinji
Published: February 2012

To clarify the growth mechanism of the lateral growth of Ge in the rapid-melting-growth process, two types of molecular-dynamics simulation were investigated in this study. One was the nucleation of Si1-x
Ge
x
(0 ≤x ≤1) from supercooled melts, and the other is the growth rate of supercooled Si1-x
Ge
x
melts using a crystalline Si1-x
Ge
x
seed. The incubation time is found to be minimum at approximately 0.70 T
m (T
m: melting temperature for Si1-x
Ge
x
). No nucleation was found when the temperature was higher than 0.75 T
m. The crystal growth rates of Si1-x
Ge
x
peaked between 0.90 T
m and 0.94 T
m for both the [100] and [111] orientations. These results suggest that 0.90 T
m to 0.94 T
m of Si1-x
Ge
x
(x = 1) is an optimum temperature range to grow crystalline Ge in the rapid-melting-growth process.
Properties of Interface between Organic Hole-Transporting Layer and Indium Tin Oxide Anode Modified by Fluorinated Self-Assembled Monolayer
Authors: Satoh Toshikazu , Imanishi Masato , Nishikawa Takao , Mori Tatsuo
Published: February 2012

The electronic structure and chemical properties of the interface between indium tin oxide (ITO) modified by a fluorinated self-assembled monolayer (F-SAM) and a N,N '-bis(1-naphthyl)-N,N '-diphenyl-1,1'-diphenyl-1,4'-diamine (α-NPD) layer were investigated in order to clarify the effects of the F-SAM modification of ITO anodes on the driving voltage and lifetime of organic light-emitting diodes (OLEDs). Ultraviolet and X-ray photoelectron spectroscopy revealed that the F-SAM modification of ITO led to a shallower highest occupied molecular orbital level in the α-NPD layer near the interface than in conventionally treated ITO, a chemical reaction between F-SAM and α-NPD, and the migration of adsorbed fluorine into the α-NPD layer. These results indicate that high conductance, the suppression of crystallization, and the inhibition of oxidation in the hole-transporting layer along with a small hole-injection barrier height at the anode/HTL interface contribute to the excellent properties of OLEDs having ITO anodes modified by F-SAM.
Fluidic Self-Assembly of Microstructures Using a Blade-Coating Technique: Influence of Volume of Water Droplets on Probability of Microstructure Placement
Authors: Arase Hidekazu , Nakagawa Tohru
Published: February 2012

Fluidic self-assembly (FSA) is a promising technique for fabricating devices that are composed of large numbers of small electronic components. We have previously proposed a printing method that utilizes the FSA principle. In our method, by simply blade-coating first water and then a dispersion liquid of microstructures on a substrate, the microstructures are automatically placed on pre-patterned hydrophilic areas by means of water/solvent interfacial force. To improve the placement probability of microstructures on the intended hydrophilic areas, in the present study we investigate the influence of the volume of water droplets on the probability of microstructure placement. We prepared various sizes of hydrophilic patterns on a glass substrate to vary the volume of water droplets in hydrophilic areas, and placed square SiO2 plates, measuring 50 ×50 ×0.3 µm3, using FSA. The probability and accuracy of placement was evaluated using a high-speed microscope, and the results were interpreted using a simple model based on capture coefficients and the collision cross section of the water droplets. We verified that the model closely fitted the experimentally obtained probability of placement as observed using the high-speed microscope. We found that the capture coefficient increased with increasing area of the water droplet. These results indicate that the size of the hydrophilic area is one key to improving the probability and accuracy of our placement technique.
Propitious Immobilization of Gold Nanoparticles on Poly(dimethylsiloxane) Substrate for Local Surface Plasmon Resonance Based Biosensor
Authors: Trung Nguyen Ba , Yoshikawa Hiroyuki , Tamiya Eiichi , Viet Pham Hung , Takamura Yuzuru , Ashahi Tsuyoshi
Published: February 2012

In this work, a simple method for fabricating gold nanoparticle (AuNP) layer on a poly(dimethylsiloxane) (PDMS) substrate based on electrostatic deposition of AuNP colloid onto a chemically-modified PDMS surface using 3-aminopropyltriethoxysilane (γ-APTES) was developed. AuNPs of 100 nm diameter were successfully dispersed and deposited onto the chemically-modified PDMS surface. The morphology and optical property of the AuNP layer were examined by atomic force microscopy (AFM) and UV–visible absorption spectroscopy, respectively. It was found that the prepared AuNP layer on PDMS could work as a localized surface plasma resonance (LSPR) sensor. The sensing characteristics were examined by changing the refractive index of solution surrounding the AuNP and antigen-antibody events on the AuNP surface. Changes in absorbance intensity and peak wavelength shift of the LSPR band were both clearly observed. The developed technique can hopefully expand the applications of PDMS for not only micro channel fabrication, but also sensing construction for easier and simpler preparation of microfluidic biosensors, which were then applied for immunoassays and other biochemical analyses.
Esophageal functional impairments in experimental eosinophilic esophagitis
Authors: Mavi Parm , Rajavelu Priya , Rayapudi Madhavi , Paul Richard J. , Mishra Anil
Published: February 2012

Eosinophilic esophagitis (EoE) is an emerging chronic esophageal disease. Despite the increasing diagnosis of EoE globally, the causes of EoE and other esophageal eosinophilic disorders are not clearly understood. EoE pathology includes accumulation of inflammatory cells (e.g., eosinophils, mast cells), characteristic endoscopic features (e.g., furrows, the formation of fine concentric mucosal rings, exudates), and functional impairments (e.g., esophageal stricture, dysmotility). We hypothesized that the esophageal structural pathology and functional impairments of EoE develop as a consequence of the effector functions of the accumulated inflammatory cells. We analyzed eosinophils (anti-major basic protein immunostaining), esophageal stricture (X-ray barium swallowing), and esophageal motility (isometric force) in two established transgenic murine models of EoE (CD2-IL-5 and rtTA-CC10-IL-13) and a novel eosinophil-deficient model (ΔdblGATA/CD2-IL-5). Herein, we show the following: 1) CD2-IL-5 and doxycycline (DOX)-induced rtTA-CC10-IL-13 mice have chronic eosinophilic and mast cell esophageal inflammation; 2) eosinophilic esophageal inflammation promotes esophageal stricture in both transgenic murine models; 3) the eosinophil-deficient ΔdblGATA/CD-2-IL-5 mice were protected from the induction of stricture, whereas the eosinophil-competent CD2-IL-5 mice develop esophageal stricture; 4) esophageal stricture is not reversible in DOX-induced rtTA-CC10-IL-13 mice (8 wk DOX followed by 8 wk no-DOX); and 5) IL-5 transgene-induced (CD2-IL-5) EoE evidences esophageal dysmotility (relaxation and contraction) that is independent of the eosinophilic esophageal inflammation: CD2-IL-5 and ΔdblGATA/CD2-IL-5 mice have comparable esophageal dysmotility. Collectively, our present study directly implicates chronic eosinophilic inflammation in the development of the esophageal structural impairments of experimental EoE.
Divergent fate and origin of neurosphere-like bodies from different layers of the gut
Authors: Becker Laren , Kulkarni Subhash , Tiwari Gunjan , Micci Maria-Adelaide , Pasricha Pankaj Jay
Published: February 2012

Enteric neural stem cells (ENSCs) are a population of neural crest-derived multipotent stem cells present in postnatal gut that may play an important role in regeneration of the enteric nervous system. In most studies, these cells have been isolated from the layer of the gut containing the myenteric plexus. However, a recent report demonstrated that neurosphere-like bodies (NLBs) containing ENSCs could be isolated from mucosal biopsy specimens from children, suggesting that ENSCs are present in multiple layers of the gut. The aim of our study was to assess whether NLBs isolated from layers of gut containing either myenteric or submucosal plexus are equivalent. We divided the mouse small intestine into two layers, one containing myenteric plexus and the other submucosal plexus, and assessed for NLB formation. Differences in NLB density, proliferation, apoptosis, neural crest origin, and phenotype were investigated. NLBs isolated from the myenteric plexus layer were present at a higher density and demonstrated greater proliferation, lower apoptosis, and higher expression of nestin, p75, Sox10, and Ret than those from submucosal plexus. Additionally, they contained a higher percentage of neural crest-derived cells (99.4 ± 1.5 vs. 0.7 ± 1.19% of Wnt1-cre:tdTomato cells; P < 0.0001) and produced more neurons and glial cells than those from submucosal plexus. NLBs from the submucosal plexus layer expressed higher CD34 and produced more smooth muscle-like cells. NLBs from the myenteric plexus layer contain more neural crest-derived ENSCs while those from submucosal plexus appear more heterogeneous, likely containing a population of mesenchymal stem cells.
Nitroso-redox balance in control of coronary vasomotor tone
Authors: Taverne Yannick J. H. J. , de Beer Vincent J. , Hoogteijling Bas A. , Juni Rio P. , Moens An L. , Duncker Dirk J. , Merkus Daphne
Published: February 2012

Reactive oxygen species (ROS) are essential in vascular homeostasis but may contribute to vascular dysfunction when excessively produced. Superoxide anion (O2·−) can directly affect vascular tone by reacting with K+ channels and indirectly by reacting with nitric oxide (NO), thereby scavenging NO and causing nitroso-redox imbalance. After myocardial infarction (MI), oxidative stress increases, favoring the imbalance and resulting in coronary vasoconstriction. Consequently, we hypothesized that ROS scavenging results in coronary vasodilation, particularly after MI, and is enhanced after inhibition of NO production. Chronically instrumented swine were studied at rest and during exercise before and after scavenging of ROS with N-(2-mercaptoproprionyl)-glycine (MPG, 20 mg/kg iv) in the presence or absence of prior inhibition of endothelial NO synthase (eNOS) with Nω-nitro-l-arginine (l-NNA, 20 mg/kg iv). In normal swine, MPG resulted in coronary vasodilation as evidenced by an increased coronary venous O2 tension, and trends toward increased coronary venous O2 saturation and decreased myocardial O2 extraction. These effects were not altered by prior inhibition of eNOS. In MI swine, MPG showed a significant vasodilator effect, which surprisingly was abolished by prior inhibition of eNOS. Moreover, eNOS dimer/monomer ratio was decreased after MI, reflecting eNOS uncoupling. In conclusion, ROS exert a small coronary vasoconstrictor influence in normal swine, which does not involve scavenging of NO. This vasoconstrictor influence of ROS is slightly enhanced after MI. Since inhibition of eNOS abolished rather than augmented the vasoconstrictor influence of ROS in swine with MI, while eNOS dimer/monomer ratio was decreased, our data imply that uncoupled eNOS may be a significant source of O2·− after MI.
Long-Term Mortality After Transvenous Lead Extraction
Authors: Maytin Melanie , Jones Samuel O. , Epstein Laurence M.
Published: February 2012

Background—

The number of cardiovascular implantable electronic devices has increased progressively and has led to an increased need for transvenous lead extraction (TLE). Multiple reports of TLE procedural outcomes exist; however, data regarding postprocedural and long-term mortality are limited.

Methods and Results—

We performed a retrospective study of consecutive patients undergoing TLE at a single, high-volume center. Patient characteristics, indications, and outcomes were analyzed. A multivariable Cox regression model was developed to identify factors associated with mortality. Between January 2000 and December 2010, 985 patients underwent 1043 TLE procedures. The cohort was 68% male, with a mean age of 63 years (range, 15–95 years) and a left ventricular ejection fraction of 40±17%. Indications included systemic infection (18%), pocket infection (32%), lead malfunction (30%), and other (device upgrade, venous occlusion, and advisory leads; 20%). There were no procedure-related deaths. The mean follow-up was 3.7 years (range, 0.1–11.3 years). Kaplan–Meier analysis demonstrated a cumulative mortality of 2.1% at 30 days, 4.2% at 3 months, 8.4% at 1 year, and 46.8% at 10 years. In multivariable analysis, systemic infection (hazard ratio [HR], 3.52; 95% CI, 1.95–6.38;
P
<0.0001), local infection (HR, 2.70; 95% CI, 1.55–4.67;
P
=0.0004), device system upgrade (HR, 2.14; 95% CI, 1.07–4.25;
P
=0.03; indication compared with a reference group of extraction for lead malfunction), diabetes mellitus (HR, 1.71; 95% CI, 1.25–2.35;
P
=0.0009), increasing age (HR, 1.05; 95% CI, 1.04–1.07;
P
<0.0001), and serum creatinine (HR, 1.16; 95% CI, 1.01–1.35;
P
=0.04) were significant correlates of increased mortality risk.

Conclusions—

Although TLE procedural mortality is exceedingly low at high-volume centers, postprocedural and long-term mortality remain high in certain patient populations, such as elderly patients and those undergoing TLE for infectious indications and device system upgrade. Information regarding TLE long-term outcomes may help guide cardiovascular implantable electronic device and lead management.
Presence of Atrial Fibrillation Is Independently Associated With Adverse Outcomes in Patients Hospitalized With Heart Failure
Authors: Mountantonakis Stavros E. , Grau-Sepulveda Maria V. , Bhatt Deepak L. , Hernandez Adrian F. , Peterson Eric D. , Fonarow Gregg C.
Published: February 2012

Background—

It is unclear if the presence of atrial fibrillation (AF) on admission is associated with worse in-hospital outcomes in patients hospitalized with heart failure (HF). This study evaluated the clinical characteristics, management, length of stay, and mortality of HF patients with and without AF.

Methods and Results—

We studied 99 810 patients from 255 sites admitted with HF enrolled in Get With The Guidelines–Heart Failure between January 1, 2005, and December 31, 2010. Patients with AF on admission were compared with patients in sinus rhythm. A total of 31 355 (31.4%) HF patients presented with AF, of which 6701 (21.3%) were newly diagnosed. Patients in AF were older (77±12 versus 70±15,
P
<0.001) and were more likely to have history of stroke and valvular heart disease. AF patients had higher B-type natriuretic peptide levels and ejection fraction (42±17% versus 39±17%,
P
<0.001). AF patients were more likely to be hospitalized >4 days (48.8% versus 41.5%,
P
<0.001), discharged to a facility other than home (28.5% versus 19.7%,
P
<0.001), and had higher hospital mortality rate (4.0% versus 2.6%,
P
<0.001). AF, particularly newly diagnosed, was independently associated with adverse outcomes (adjusted odds ratios and 95% confidence intervals for mortality 1.17, 1.05–1.29,
P
=0.0029, and 1.29, 1.10–1.52,
P
=0.0023 for AF and newly diagnosed AF, respectively).

Conclusions—

In patients hospitalized with HF, AF is present in one-third and is independently associated with adverse hospital outcomes and longer length of stay. Whether prompt restoration of sinus rhythm would improve outcomes in patients hospitalized with HF and new-onset or paroxysmal AF is unclear and requires further study.