bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Similarity Solution for Condensation Heat Transfer
Authors: Tamm Gunnar , Boettner Daisie D. , Van Poppel Bret P. , Benson Michael J. , Arnas A. Özer
Published: August 2009

Analytical solutions for laminar film condensation on a vertical plate are integral to many heat transfer applications, and have therefore been presented in numerous refereed articles and in most heat transfer textbooks. Commonly made assumptions achieve the well known similarity solution for the Nusselt number, heat transfer coefficient, and film thickness. Yet in all of these studies, several critical assumptions are made without justifying their use. Consequently, for a given problem one cannot determine whether these restrictive assumptions are actually satisfied, and thus, how these conditions can be checked for validity of the results. This study provides a detailed solution that clarifies these points.
Heat Transfer During Deposition of Molten Aluminum Alloy Droplets to Build Vertical Columns
Authors: Fang M. , Chandra S. , Park C. B.
Published: August 2009

To create functional metal parts by depositing molten metal droplets on top of each other, we have to obtain good metallurgical bonding between droplets. To investigate conditions under which such bonds are achieved, experiments were conducted in which vertical columns were formed by depositing molten aluminum alloy (A380) droplets on top of each other. A pneumatic droplet generator was used to create uniform, 0.8 mm diameter, molten aluminum droplets. The droplet generator was mounted on a stepper motor and moved constantly so as to maintain a fixed distance between the generator nozzle and the tip of the column being formed. The primary parameters varied in experiments were those found to have the strongest effect on bonding between droplets: substrate temperature (250–450°C) and deposition rate (1–8 Hz). Droplet temperature was constant at 620°C. To achieve metallurgical bonding between droplets, the tip temperature of the column should be maintained slightly below the melting temperature of the alloy to ensure remelting under an impacting drop and good bonding. The temperature cannot exceed the melting point of the metal; otherwise the column tip melts down. The temperature at the bottom of a column was measured while droplets were being deposited. An analytical one-dimensional heat conduction model was developed to obtain the transient temperature profile of the column, assuming the column and the substrate to be a semi-infinite body exposed to a periodic heat flux. From the model, the droplet deposition frequency required to maintain the tip temperature at the melting point of the metal was calculated.
An Experimental Study of the Effects of Platinum on Methane/Air and Propane/Air Mixtures in a Stagnation Point Flow Reactor
Authors: Wiswall James T. , Wooldridge Margaret S. , Im Hong G.
Published: August 2009

A stagnation-flow burner facility was used to study the catalytic surface reactions of premixed combustion systems at atmospheric pressure. The configuration serves as an important platform to investigate the interaction between homogeneous and heterogeneous reactions with independent control of the characteristic chemical and physical residence time scales. Methane/oxygen/nitrogen and propane/oxygen/nitrogen mixtures were examined with and without the presence of a platinum catalyst located at the stagnation surface. The effects of oxidizer composition and nitrogen dilution were investigated. Lean flame extinction limits were determined for the two fuels and were found to be unaffected by the presence of the catalytic surface. The flame extinction data indicated that the systems were controlled by gas phase combustion with negligible contributions from heterogeneous reactions. The catalytic activity of the heated surface in response to the direct impingement of fuel/air mixtures onto the stagnation surface, without the presence of a flame, was quantified by the increase in the surface temperature. The methane/air mixtures demonstrated no catalytic activity for these conditions, whereas propane/air mixtures demonstrated temperature increases of over 100 K. The data indicate that the surface reaction was transport limited for the propane/air system.
Turbomolecular pump rotor-bearing system analysis and testing
Authors: Chiang Hsiao-Wei D. , Kuan Chih-Pin , Li Hsin-Lung
Published: August 2009

During turbomolecular pump design, it is very critical to know the dynamic behavior of the rotor-bearing system, which is also of great importance to the pump performance. In this study, a typical small size turbomolecular pump was used. Using an inertial coordinate system, the dynamic models of the pump rotor-bearing systems included gyroscopic moments, rotary inertias, and bending and shear deformations. The models were analyzed in order to predict the natural frequencies, to produce critical speed maps, and to estimate the bearing stiffness. These rotor-bearing system analyses were then applied to the turbomolecular pump rotor system applications. Both theoretical and experimental analyses were used to study the rotor-bearing system. Modal testing and dynamic test were used to verify the analytical results, including the critical speed map and the bearing stiffness. Very good agreement was demonstrated between the analysis and the test data. The analysis demonstrated that the rotor operation of 51600rpm is very close to the second critical speed, which may have caused the recent pump bearing failures near the pump bottom. The analysis can also provide guidelines to avoid the second order critical speed mode shape failures.
Effect of Ta buffer layer and thickness on the structural and magnetic properties of Co thin films
Authors: Vahaplar K. , Tari S. , Tokuc H. , Okur S.
Published: August 2009

Single Co and Ta/Co bilayers were grown on Si(100) substrates in a magnetron sputtering system. The effect of Ta buffer layer and the thickness of Co layer on the structural and magnetic properties of the Co layers has been studied. A single Co layer shows a textured structure above thickness of 40 nm according to the x-ray diffraction (XRD) pattern. The magnetic properties of Co layers depend significantly on the thickness of the films. Ta grows as highly textured β-Ta (tetragonal) phase on Si with a smooth surface. The XRD and atomic force microscopy results show that the Ta buffer layer improves the structural properties dramatically, resulting in a strongly textured and smoother surface morphology. The Ta layer also affects the magnetic properties of Co layers to a large extent, especially inducing an in-plane anisotropy in thin Co films.
Structural and electrical properties of metal contacts on n-type ZnO thin film deposited by vacuum coating technique
Authors: Periasamy C. , Chakrabarti P.
Published: August 2009

The authors report on fabrication and characterization of Al and Pt metal contacts on ZnO thin films grown on ITO coated glass substrates using thermal evaporation technique. The structural and surface properties of ZnO thin film were studied by using x-ray diffraction and atomic force microscopy techniques. Atomic force micrographs revealed that ZnO microparticles have perfect pyramidal shape with small surface roughness (average rms value of 3nm). The current voltage characteristics of Pt∕ZnO and Al∕ZnO contacts were studied by scanning tunneling microscopy. The Pt contact on ZnO thin films behaves as a rectifying contact with a barrier height of 0.72eV, while Al contact on ZnO thin film turns out to be Ohmic in nature. The band gap of ZnO thin film was estimated to be 3.10eV from absorption spectroscopic measurements.
Transparent dual-gate InGaZnO thin film transistors: OR gate operation
Authors: Lim Wantae , Douglas E. A. , Lee Jaewon , Jang Junghun , Craciun V. , Norton D. P. , Pearton S. J. , Ren F. , Son S. Y. , Yuh J. H. , Shen H. , Chang W.
Published: August 2009

Transparent dual-gate (DG) InGaZnO4 thin film transistors for OR logic operation were fabricated on a glass substrate. A 100-nm-thick SiO2 layer used as both top and bottom gate dielectrics was deposited by plasma enhance chemical vapor deposition at 200°C. Compared to bottom gate, top gate thin film transistors (TFTs) exhibited better device performance with higher saturation mobility, drain current on-to-off ratio, lower threshold voltage, and subthreshold gate-voltage swing. This improved performance was mainly attributed to low process-induced damage or low parasitic capacitance between gate and source/drain and low parasitic resistance between channel and source/drain in top-contact TFT configuration (coplanar type). DG-mode TFTs showed saturation mobility of ∼16.9cm2V−1s−1, drain current on-to-off ratio of ∼1×106, subthreshold gate-voltage swing of ∼0.33Vdecade−1, and threshold voltage of ∼1.25V. The results demonstrate that DG InGaZnO4 TFTs are effective in improving the device performance because the channel layer is modulated independently by a top or, bottom gate signal and are well suited for OR gate operation.
Techniques of cryogenic reactive ion etching in silicon for fabrication of sensors
Authors: Henry M. David , Welch Colin , Scherer Axel
Published: August 2009

Cryogenic etching of silicon, using an inductively coupled plasma reactive ion etcher (ICP-RIE), has extraordinary properties which can lead to unique structures difficult to achieve using other etching methods. In this work, the authors demonstrate the application of ICP-RIE techniques which capitalize on the cryogenic properties to create different sensors geometries: optical, electrical, magnetic, and mechanical. The three techniques demonstrated are (1) single step deep etches with controllable sidewall profiles. Demonstrating this, silicon pillars with over 70μm depth and less than 250nm sidewall roughness were etched using only 1.6μm of photoresist for use as solar cells. (2) Using the cryogenic etch for thick metallization and liftoff with a thin photoresist mask. Demonstrating this second technique, a magnetic shim was created by deposition of 6.5μm of iron into 20μm deep etched trenches, using the remaining 1.5μm photoresist etch mask as the liftoff mask. Using the same technique, 15μm of copper was lifted off leaving a 20μm deep plasma enhanced chemical vapor deposition silicon oxide coated, silicon channel with copper. (3) Use of a two step cryogenic etch for deep etching with reduced sidewall undercutting. This was demonstrated by fabrication of deep and anisotropic microelectromechanical systems structures; a mechanical resonator was etched 183μm deep into silicon with less than 3μm of undercutting. This work also describes the etch parameters and etch controls for each of these sensors.
Formation and evolution of craters in carbon steels during low-energy high-current pulsed electron-beam treatment
Authors: Zhang Kemin , Zou Jianxin , Grosdidier Thierry , Dong Chuang
Published: August 2009

The authors investigated in detail the formation and evolution of microcraters induced by low-energy high-current pulsed electron-beam treatment on several quenched and tempered carbon steels. They have shown that the crater formation mechanism is the same for the three selected steels regardless of the carbon content and original microstructure state. Melting starts at the subsurface layer during treatment, resulting in the nucleation of small droplets preferentially at grain or phase boundaries. Under further heating, the boiling droplets erupt through the surface. The liquid around these craters shrinks to supply the lost part and, during the cooling process, leads to the formation of the funnel-like crater morphology. Microirregularities help retain locally the heat flux and, consequently, serve as nucleation sites for crater formations. By increasing the number of pulses, microirregularities were gradually removed and melted layer depth increased. As a result, crater formation became less effective. On the other hand, some of the already formed craters were deepened, while others were eliminated during the following pulses. The above processes together cause the crater density to first increase and then decrease, whereas the surface roughness first increases and then remains at the same level with increasing number of pulses.
Human papillomavirus prevalence and type distribution in penile carcinoma
Authors: Miralles-Guri C , Bruni L , Cubilla A L , Castellsagué X , Bosch F X , de Sanjosé S
Published: August 2009

Background:

Penile carcinoma is an uncommon and potentially mutilating disease with a heterogeneous aetiology. Several risk factors have been established for its development. Human papillomavirus (HPV) infection seems to play an important role in the development of a subset of these carcinomas and its presence is thought to be related to the histological type. HPV prevalence in penile tumours is reported to be associated to a variety of morphological changes. Its determination will provide a better estimate for HPV related cancer burden and its preventable fraction.

Methods:

A systematic and comprehensive literature review of the major penile cancer studies published from 1986 until June 2008 evaluating the HPV prevalence among the different histological types was carried out.

Results:

31 studies including 1466 penile carcinomas were reviewed. Global HPV prevalence was 46.9%. Relative contribution was: HPV-16 (60.23%), HPV-18 (13.35%), HPV-6/11 (8.13%), HPV-31 (1.16%), HPV-45 (1.16%), HPV-33 (0.97%), HPV-52 (0.58%), other types (2.47%). Assessment of multiple infections contribution is limited due to study design. Basaloid and warty squamous cell carcinomas were the most frequent HPV-related histological types, but keratinising and non-keratinising subtypes also showed prevalence rates of around 50%.

Conclusions:

About half of the penile tumours were associated with HPV 16–18 with little presence of other genotypes. Research on the mechanisms behind penile carcinogenesis is warranted. Available HPV vaccines are likely to be effective in penile tumours.
ON THE STRING EQUATION OF THE BKP HIERARCHY
Authors: SHEN HSIN-FU , TU MING-HSIEN
Published: August 2009

The Adler–Shiota–van Moerbeke formula is employed to derive the W-constraints for the p-reduced BKP hierarchy constrained by the string equation. We also provide the Grassmannian description of the string equation in terms of the spectral parameter.
NONLEPTONIC ANNIHILATION DECAYS OF B MESON WITH A NATURAL INFRARED CUTOFF
Authors: NATALE A. A. , ZANETTI C. M.
Published: August 2009

Within the QCD factorization approach we compute the amplitudes for pure annihilation channels of B mesons decays into final states containing two pseudoscalar particles. These decays may be plagued by effects like nonperturbative physics and breaking of the factorization hypothesis and imply, at some extent, the introduction of an infrared cutoff in the calculation of amplitudes. We compute the decays with the help of infrared finite gluon propagators and coupling constants that were obtained in different solutions of the QCD Schwinger–Dyson equations. These solutions yield a natural cutoff for the amplitudes, and we argue that a systematic study of these B decays may provide a test for the QCD infrared behavior.
ON THE YANG–MILLS AND QCD SPECTRA FROM FIVE-DIMENSIONAL STRINGS
Authors: COTRONE ALDO L.
Published: August 2009

We consider a noncritical five-dimensional string setup which could provide a dual description of QCD in the limit of large number of colors and flavors. The model corresponds to Nc color D3-branes and Nf D4/anti-D4-brane pairs supporting flavor degrees of freedom. The matching of the string model spectrum with the dual field theory one is considered. We discuss the consequences of the possible matching of the gravity modes with the light glueballs and the interpretation of the brane spectrum in Yang–Mills and QCD.
OCTONIC FIRST-ORDER EQUATIONS OF RELATIVISTIC QUANTUM MECHANICS
Authors: MIRONOV VICTOR L. , MIRONOV SERGEY V.
Published: August 2009

We demonstrate a generalization of relativistic quantum mechanics using eight-component octonic wave function and octonic spatial operators. It is shown that the second-order equation for octonic wave function describing particles with spin 1/2 can be reformulated in the form of a system of first-order equations for quantum fields, which is analogous to the system of Maxwell equations for the electromagnetic field. It is established that for the special types of wave functions the second-order equation can be reduced to the single first-order equation analogous to the Dirac equation. At the same time it is shown that this first-order equation describes particles, which do not have quantum fields.
PROGRESS IN FOUR-DIMENSIONAL LATTICE SUPERSYMMETRY
Authors: GIEDT JOEL
Published: August 2009

We are entering an era where a number of large-scale lattice simulations of four-dimensional supersymmetric theories are under way. Moreover, proposals for how to approach such studies continue to progress. One particular line of research in this direction is described here. General actions for super-QCD, including counterterms required on the lattice, are given. We obtain the number of fine-tunings that is required, once gauge and flavor symmetries are accounted for, provided Ginsparg–Wilson fermions are used for the gauginos. We also review and extend our recent work on lattice formulations of [Formula: see text] super-Yang–Mills and [Formula: see text] super-Yang–Mills that exploit Ginsparg–Wilson fermions.
STUDY OF SOUND SOURCE IDENTIFICATION BASED ON BEAMFORMING AND PATCH NEAR-FIELD ACOUSTIC HOLOGRAPHY
Authors: JIA WENQIANG , CHEN JIN , YANG CHAO , LI JIAQING
Published: August 2009

A study for applying data extrapolation technique based on wave superposition method (WSM) is proposed to overcome the disadvantages of near-field acoustical holography (NAH). Unlike conformal NAH, where the measurement surface surrounds the entire structure, in the patch holography the measurement surface needs only be approximately as large as the patch on the structure surface where the reconstruction is required. At first, a microphone array is used to acquire the sound pressure field radiated from a vibrator; then a beamforming method is adopted to locate sound sources; after that, a serial of equivalent sources are collocated around these sound sources; at last, a data extrapolation technique based on WSM is applied to extend the measurement aperture and reconstruct the sound field. Since the data extrapolation algorithm requires the inversion of Green's function matrix which may be ill-conditioned, Tikhonov regularization method is used to invert it, and the value of the regularization parameter is determined by the L-curve criteria. The effectiveness of this method is demonstrated by numerical simulation with two pulse ball model, and also experiment is carried out in a semi-anechoic chamber using two sound boxes. The results confirm that the exterior sound field can be accurately reconstructed with few iterative times and the reconstruction error is sufficiently suppressed by the proposed method.
EXISTENCE AND UNIQUENESS OF POSITIVE SOLUTIONS TO ELLIPTIC PROBLEMS WITH SUBLINEAR MIXED BOUNDARY CONDITIONS
Authors: GARCÍA-MELIÁN JORGE , ROSSI JULIO D. , SABINA DE LIS JOSÉ C.
Published: August 2009

In this work, we consider a class of semilinear elliptic problems with nonlinear boundary conditions of mixed type. Under some monotonicity properties of the nonlinearities involved, we show that positive solutions are unique, and that their existence is characterized by the sign of some associated eigenvalues. One of the most important contributions of this work relies on the fact that we deal with boundary conditions of the form ∂u/∂ν = g(x,u) on Γ and u = 0 on Γ', where ν is the outward unit normal to Γ while Γ,Γ' are open, Γ ∩ Γ' = ∅, [Formula: see text], but [Formula: see text] need not be disjoint.
A NEW FAULT PATTERN RECOGNITION METHOD BASED ON WPT AND DAGSVM
Authors: XIAN GUANG-MING , ZENG BI-QING
Published: August 2009

A new pattern recognition method based on wavelet packet transform (WPT) and directed acyclic graph support vector machine (DAGSVM) is put forward for fault diagnosis of roller bearing. The fault pattern recognition model setup has two phases. The first phase is to extract the feature of faulty vibration signals from roller bearing by WPT via a db3 wavelet. The second phase is to use DAGSVM to recognize fault pattern of roller bearing. The testing results illustrates that WPT is more effective to diagnose fault types than the WT method. It is observed that among the strategy of multi-class SVM, DAGSVM acquires the highest accuracy, and therefore, this demonstrates the fact that suitable fault pattern recognition strategy can improve the overall performance of fault diagnosis. The present research illustrated that the features extracted by WPT represent the fault pattern of roller bearing, and the DAGSVM trained on these features achieved high recognition accuracies.
Spike-Type Compressor Stall Inception, Detection, and Control
Authors: Tan C.S. , Day I. , Morris S. , Wadia A.
Published: August 2009

An aerodynamic instability known as stall occurs in axial compressors as the mass flow rate is reduced and the blade loading reaches its limit. At this limiting condition, an easily recognizable flow breakdown process, known as spike-type stall inception, is observed in most modern compressors. This article begins by examining measurements from both low- and high-speed compressors to explain the characteristic features of spike-type stall. This is followed by a review of past work on compressor stability and an assessment of recent advances in this field. Included here is a study of the three-dimensional flow features that typify spike formation and its eventual growth into a mature stall cell. We also consider the formation criteria for spike-type stall and the means for early detection and possible control. On the computational side, a possible mechanism for spike formation is identified from three-dimensional studies of the flow in the rotor tip region. This mechanism involves tip-clearance backflow at the blade's trailing edge in combination with forward spillage of tip-leakage flow at the leading edge. This flow pattern implies that a successful stall-control technology will have to rely on an effective means of suppressing tip-clearance backflow and forward spillage.
Overexpression of the nuclear factor-κB subunit c-Rel protects against human islet cell death in vitro
Authors: Mokhtari Dariush , Barbu Andreea , Mehmeti Ilir , Vercamer Chantal , Welsh Nils
Published: August 2009

The transcription factor nuclear factor (NF)-κB is known to modulate rates of apoptosis and may therefore play a role in the increased β-cell death that occurs in type 1 and type 2 diabetes. The aim of the present investigation was to study the expression of NF-κB subunits in human islet cells and whether overexpression of the NF-κB subunit c-Rel affects islet cell survival. We detected expression of p65, Rel-B, p50, p105, p52, and the ribosomal protein S3 (rpS3) in human islet cells. Among these, only p65 and rpS3 were translocated from the cytosolic to the nuclear fraction in response to cytokines. Interestingly, rpS3 participated in p65 binding to the κB-element in gel shift analysis experiments. We observed cytoplasmic c-Rel expression in vivo in 6J mice, and signs of nuclear translocation in β-cells of infiltrated nonobese diabetic islets. Human islet cells were also dispersed by trypsin treatment and transduced with a c-Rel adenoviral vector. This resulted in increased expression of c-Rel and inhibitory factor κB, increased κB-binding activity, and augmented protein levels of Bcl-XL,c-IAP2, and heat shock protein 72. c-Rel expression in human islet cells protected against cytokine-induced caspase 3 activation and cell death. c-Rel protected also against streptozotocin- and H2O2-induced cell death, in both intact rat islets and human islet cells. We conclude that rpS3 participates in NF-κB signaling and that a genetic increase in the activity of the NF-κB subunit c-Rel results in protection against cell death in human islets.
TIP39/parathyroid hormone type 2 receptor signaling is a potent inhibitor of chondrocyte proliferation and differentiation
Authors: Panda Dibiyendu , Goltzman David , Jüppner Harald , Karaplis Andrew C.
Published: August 2009

Tuberoinfundibular peptide of 39 residues (TIP39) is a member of the parathyroid hormone (PTH) family of peptide hormones that exerts its function by interacting with the PTH type 2 receptor (PTH2R). Presently, no known function has been attributed to this signaling pathway in the developing skeleton. We observed that TIP39 and PTH2R were present in the newborn mouse growth plate, with the receptor localizing in the resting zone whereas ligand expression was restricted exclusively in prehypertrophic and hypertrophic chondrocytes. By 8 wk of life, PTH2R, and to a lesser degree TIP39, immunoreactivity was present in articular chondrocytes. We therefore sought to investigate the role of TIP39/PTH2R signaling in chondrocytes by generating stably transfected CFK2 chondrocytic cells overexpressing PTH2R (CFK2R). TIP39 treatment of CFK2R clones in culture inhibited their proliferation by restricting cells at the G0/G1 phase of the cell cycle, coupled with decreased expression and activity of cyclin-dependent kinases Cdk2 and Cdk4, while p21, an inhibitor of Cdks, was upregulated. In addition, TIP39 treatment decreased expression of differentiation markers in these cells associated with marked alterations in extracellular matrix and metalloproteinase expression. Transcription of Sox9, the master regulator of cartilage differentiation, was reduced in TIP39-treated CFK2R clones. Moreover, Sox9 promoter activity, as measured by luciferase reporter assay, was markedly diminished after TIP39 treatment. In summary, our results show that TIP39/PTH2R signaling inhibits proliferation and alters differentiation of chondrocytes by modulating SOX9 expression, thereby substantiating the functional significance of this signaling pathway in chondrocyte biology.
Effects of hormone-sensitive lipase disruption on cardiac energy metabolism in response to fasting and refeeding
Authors: Suzuki Jinya , Ueno Masami , Uno Miyuki , Hirose Yoshikazu , Zenimaru Yasuo , Takahashi Sadao , Osuga Jun-ichi , Ishibashi Shun , Takahashi Masafumi , Hirose Masamichi , Yamada Mitsuhiko , Kraemer Fredric B. , Miyamori Isamu
Published: August 2009

Increased fatty acid (FA) flux and intracellular lipid accumulation (steatosis) give rise to cardiac lipotoxicity in both pathological and physiological conditions. Since hormone-sensitive lipase (HSL) contributes to intracellular lipolysis in adipose tissue and heart, we investigated the impact of HSL disruption on cardiac energy metabolism in response to fasting and refeeding. HSL-knockout (KO) mice and wild-type (WT) littermates were fasted for 24 h, followed by ∼6 h of refeeding. Plasma FA concentration in WT mice was elevated twofold with fasting, whereas KO mice lacked this elevation, resulting in twofold lower cardiac FA uptake compared with WT mice. Echocardiography showed that fractional shortening was 15% decreased during fasting in WT mice and was associated with steatosis, whereas both of these changes were absent in KO mice. Compared with Langendorff-perfused hearts isolated from fasted WT mice, the isolated KO hearts also displayed higher contractile function and a blunted response to FA. Although cardiac glucose uptake in KO mice was comparable with WT mice under all conditions tested, cardiac VLDL uptake and lipoprotein lipase (LPL) activity were twofold higher in KO mice during fasting. The KO hearts showed undetectable activity of neutral cholesteryl esterase and 40% lower non-LPL triglyceride lipase activity compared with WT hearts in refed conditions accompanied by overt steatosis, normal cardiac function, and increased mRNA expression of adipose differentiation-related protein. Thus, the dissociation between cardiac steatosis and functional sequelae observed in HSL-KO mice suggests that excess FA influx, rather than steatosis per se, appears to play an important role in the pathogenesis of cardiac lipotoxicity.
Chemotherapy-induced kaolin intake is increased by lesion of the lateral parabrachial nucleus of the rat
Authors: Horn Charles C. , De Jonghe Bart C. , Matyas Kathleen , Norgren Ralph
Published: August 2009

Anticancer agents, such as cisplatin, stimulate nausea, vomiting, and behaviors indicative of malaise. Rats and mice do not possess a vomiting response, and, therefore, in these species, the ingestion of kaolin clay (a pica response) has been used as an index of malaise. In the rat, cisplatin-induced kaolin intake is inhibited by antiemetic treatments. In addition, cisplatin activates vagal afferent fibers in the gut, and kaolin intake induced by cisplatin is largely dependent on an intact vagus. Nevertheless, little is known about the brain pathways controlling pica. We investigated the role of the lateral parabrachial nucleus (lPBN), a major visceral afferent link between the hindbrain and forebrain, in cisplatin-induced c-Fos expression and pica. Injection of cisplatin (6 mg/kg ip) produced c-Fos expression in the ventrolateral (external) lPBN, a region receiving viscerosensory input. In rats with bilateral ibotenic acid lPBN lesions, cisplatin treatment substantially increased kaolin intake compared with controls (∼30 g vs. ∼5 g, respectively, over 24 h). Food intake was reduced by cisplatin treatment and by apomorphine, an emetic agent that acts centrally. Unlike cisplatin, however, apomorphine stimulated kaolin intake to a similar degree in both the lesioned and control rats, suggesting that lPBN damage neither produces nonspecific effects nor enhances malaise in general. These data suggest that lPBN-lesioned animals not only demonstrate pica after cisplatin treatment, but, in fact, show an exaggerated response that is greatly in excess of any treatment known to produce kaolin intake in rats.
Transfer of Dynamic Learning Across Postures
Authors: Ahmed Alaa A. , Wolpert Daniel M.
Published: August 2009

When learning a difficult motor task, we often decompose the task so that the control of individual body segments is practiced in isolation. But on re-composition, the combined movements can result in novel and possibly complex internal forces between the body segments that were not experienced (or did not need to be compensated for) during isolated practice. Here we investigate whether dynamics learned in isolation by one part of the body can be used by other parts of the body to immediately predict and compensate for novel forces between body segments. Subjects reached to targets while holding the handle of a robotic, force-generating manipulandum. One group of subjects was initially exposed to the novel robot dynamics while seated and was then tested in a standing position. A second group was tested in the reverse order: standing then sitting. Both groups adapted their arm dynamics to the novel environment, and this movement learning transferred between seated and standing postures and vice versa. Both groups also generated anticipatory postural adjustments when standing and exposed to the force field for several trials. In the group that had learned the dynamics while seated, the appropriate postural adjustments were observed on the very first reach on standing. These results suggest that the CNS can immediately anticipate the effect of learned movement dynamics on a novel whole-body posture. The results support the existence of separate mappings for posture and movement, which encode similar dynamics but can be adapted independently.
EEG Generator—A Model of Potentials in a Volume Conductor
Authors: Avitan Lilach , Teicher Mina , Abeles Moshe
Published: August 2009

EEG generator—a model of potentials in a volume conductor. The potential recorded over the cortex electro-corticogram (ECoG) or over the scalp [electroencephalograph (EEG)] derives from the activity of many sources known as “EEG generators.” The recorded amplitude is basically a function of the unitary potential of a generator and the statistical relationship between different EEG generators in the recorded population. In this study, we first suggest a new definition of the EEG generator. We use the theory of potentials in a volume conductor and model the contribution of a single synapse activated to the surface potential. We then model the contribution of the generator to the surface potential. Once the generator and its contribution are well defined, we can quantitatively assess the degree of synchronization among generators. The measures obtained by the model for a real life scenario of a group of generators organized in a specific statistical way were consistent with the expected values that were reported experimentally. The study sheds new light on macroscopic modeling approaches which make use of mean soma membrane potential. We showed major contribution of activity of superficial apical synapses to the ECoG signal recorded relative to lower somatic or basal synapses activity.
X-ray powder diffraction data of lapatinib ditosylate monohydrate
Authors: Varlashkin Peter
Published: August 2009

The room temperature powder pattern of lapatinib ditosylate monohydrate (active ingredient in Tykerb used to treat refractory breast cancer) was indexed and the cell from the single crystal X-ray diffraction structure was refined using the experimental capillary data. Unit-cell parameters for the orthorhombic compound with space group Pbca refined from powder diffraction data are a=9.6850±0.0009 Å, b=29.364±0.003 Å, and c=30.733±0.003 Å, α=β=γ=90°, z=8, V=8740.1 Å3. Values of 2θ, d, I, and Miller indices are reported.
Dislocations, crystallite size, and planar faults in nanocrystalline ceria
Authors: Aghdaee S. R. , Soleimanian V.
Published: August 2009

The modified Williamson–Hall and Warren–Averbach methods were used successfully for analyzing experimentally observed anisotropic X-ray diffraction line broadening and for determining reliable values of crystallite size and dislocation density in cerium oxide. The modified Williamson–Hall plot gives 22.3(2) nm for volume-weighted crystallite size, while the modified Warren–Averbach produces 18.0(2) nm for area-weighted grain size. The dislocation density and effective outer cut-off radius of dislocations obtained from the modified Warren–Averbach method are 1.8(3)×1015 m−2 and 15.5(1) nm, respectively.
Influence of the X-ray diffraction line profile analysis method on the structural and microstructural parameters determination of sol-gel TiO2 powders
Authors: Vives Serge , Meunier Cathy
Published: August 2009

Four sol-gel TiO2 powders have been prepared from titanium tetraisopropoxide. The calcined powders are then characterized by X-ray diffraction. Cell parameters are extracted using two Rietveld refinement programs (FULLPROF and MAUD) leading to close values and indicating a contraction of the a (or b) cell parameter and an expansion of the c cell parameter of the anatase phase with temperature. Crystallite size and microstrain are highly dependent not only on the sol synthesis but also on the diffraction line profile analysis (LPA) models (i.e., Williamson-Hall, Thomson-Cox-Hastings, Dehlez et al., and log-normal size distribution) employed. Discrepancies are then observed for the phase transformation critical size, the activation energy of grain growth, and the microstrain stored potential energy according to the LPA approach used to calculate the microstructural parameters.
Reinvestigation of crystal structure and structural disorder of Ba3MgSi2O8
Authors: Iwata Tomoyuki , Horie Tatsuya , Fukuda Koichiro
Published: August 2009

Crystal structure and structural disorder of Ba3MgSi2O8were reinvestigated by laboratory X-ray powder diffraction. The title compound was found to be trigonal with space groupP3m1,Z=1, and unit-cell dimensionsa=0.561 453(4) nm,c=0.727 629(4) nm, andV=0.198 641(2) nm3. The initial structural model used for structure refinement was taken from that of glaserite (K3NaS2O8) and modified by a split-atom model. In the split-atom model, one of the two types of Ba sites and that of SiO4tetrahedra were, respectively, positionally and orientationally disordered. The new crystal structure and structural disorder were refined by the Rietveld method. The maximum-entropy-method-based pattern fitting (MPF) method was used to confirm the validity of the split-atom model, in which conventional structure bias caused by assuming intensity partitioning was minimized. The final reliability indices calculated from MPF wereRwp=6.52%,S=1.36,Rp=4.84%,RB=0.97%, andRF=0.52%. Details of the disorder structure of Ba3MgSi2O8are shown in the three-dimensional and two-dimensional electron-density distribution maps determined by MPF.
Synthesis and characterization of (NH4)1.5Cu2Cr2O8(OH)1.5⋅H2O
Authors: Arboleda Johana , Echavarria Adriana , Palacio Luz Amparo
Published: August 2009

A new single-phase copper chromate compound was successfully synthesized by a hydrothermal method and characterized by XRD, SEM, TGA, and XRF analysis. The experimental XRD pattern was analyzed by automatic indexing and the compound was found to be monoclinic with space group P21/a and unit-cell parameters of a=10.1829(11) Å, b=4.9516(6) Å, c=7.2899(7) Å, and β=103.64(1)°. The chemical formula of the copper chromate compound determined by XRF and TGA was determined to be (NH4)1.5Cu2Cr2O8(OH)1.5⋅H2O. XRD results also showed that the synthesized compound decomposed into CuCr2O4 and CuO after being calcined at 600 °C.
Kinetic analysis of the phase transformation from α- to β-copper phthalocyanine: A case study for sequential and parametric Rietveld refinements
Authors: Müller Melanie , Dinnebier Robert E. , Jansen Martin , Wiedemann Stefan , Plüg Carsten
Published: August 2009

The solid-state phase transformation from α- to β-copper phthalocyanine, using isothermal data obtained at T=250 °C and nonisothermal data obtained in the temperature range of 30 °C≤T≤330 °C with a constant heating rate of 1.67 °/min, was investigated by sequential and parametric full quantitative Rietveld analyses. Results obtained in this study show that the parametric Rietveld refinement technique is most suitable and applicable for kinetic studies of isothermal powder diffraction data. On the other hand, the sequential Rietveld refinement technique can give reliable results for the kinetic analysis of nonisothermal data. The main advantages of the parametric Rietveld refinement over the sequential Rietveld refinement are increased robustness against outliers, low weight fractions, and noisy data and an increase in computational speed.
Synthesis and crystal structure refinement by the Rietveld method of antimony-bearing titanite Ca(Ti0.6Al0.2Sb0.2)OSiO4
Authors: Colombo Fernando , Miner Elisa V. Pannunzio
Published: August 2009

A synthetic analogue, Ca(Ti0.6Al0.2Sb0.2)OSiO4, of antimony-bearing titanite of a composition similar to that found at St. Marcel-Praborna (Italy) was synthesized using ceramic methods and the crystal structure was refined using the Rietveld method. Unit-cell dimensions (in Å) area=7.0184(1),b=8.7097(2),c=6.5586(1), andβ=113.700(1)°. The substitution of 40% Ti by (Al+Sb) in octahedra causes a loss of long-range coherency of the off-centered Ti atoms. The space group of Sb-bearing titanite isA2/a, like other cases ofM3+-M5+-doped titanites. This study confirms that titanite with up to 0.2 Sb atom per f.u. can exist and that the substitution scheme is 2Ti4+↔Al3++Sb5+.
Ab initio structure determination of nanosized θ-KAlF4 with edge-sharing AlF6 octahedra
Authors: Le Bail A.
Published: August 2009

θ-KAlF4 is a new nanosized potassium tetrafluoroaluminate metastable polymorph (13×18×55 nm3). The crystal structure is solved ab initio from X-ray powder diffraction data in direct space [orthorhombic unit cell with a=8.3242(3) Å, b=7.2502(3) Å, c=11.8875(4) Å, V=717.44(5) Å3, Z=8, and space group Pnma]. This new structure type, unique in the whole AIMIIIF4 family, is related to the fluorite structure and consists of AlF6 octahedra linked via a common edge forming a bioctahedral motif which is trans-connected through the corner-shared fluorine, resulting in the formation of infinite ladderlike double file of octahedra ([Al2F8]2−)n running along the b axis.
Third structure determination by powder diffractometry round robin (SDPDRR-3)
Authors: Le Bail A. , Cranswick L. M. D. , Adil K. , Altomare A. , Avdeev M. , Cerny R. , Cuocci C. , Giacovazzo C. , Halasz I. , Lapidus S. H. , Louwen J. N. , Moliterni A. , Palatinus L. , Rizzi R. , Schilder E. C. , Stephens P. W. , Stone K. H. , van Mechelen J.
Published: August 2009

The results from a third structure determination by powder diffractometry (SDPD) round robin are discussed. From the 175 potential participants having downloaded the powder data, nine sent a total of 12 solutions (8 and 4 for samples 1 and 2, respectively, a tetrahydrated calcium tartrate and a lanthanum tungstate). Participants used seven different computer programs for structure solution (ESPOIR,EXPO,FOX,PSSP,SHELXS,SUPERFLIP, andTOPAS), applying Patterson, direct methods, direct space methods, and charge flipping approach. It is concluded that solving a structure from powder data remains a challenge, at least one order of magnitude more difficult than solving a problem with similar complexity from single-crystal data. Nevertheless, a few more steps in the direction of increasing the SDPD rate of success were accomplished since the two previous round robins: this time, not only the computer program developers were successful but also some users. No result was obtained from crystal structure prediction experts.
GPU‐Based 3D Cone‐Beam CT Image Reconstruction for Large Data Volume
Authors: Zhao Xing , Hu Jing-jing , Zhang Peng
Published: August 2009

Currently, 3D cone‐beam CT image reconstruction speed is still a severe limitation for clinical application. The computational power of modern graphics processing units (GPUs) has been harnessed to provide impressive acceleration of 3D volume image reconstruction. For extra large data volume exceeding the physical graphic memory of GPU, a straightforward compromise is to divide data volume into blocks. Different from the conventional Octree partition method, a new partition scheme is proposed in this paper. This method divides both projection data and reconstructed image volume into subsets according to geometric symmetries in circular cone‐beam projection layout, and a fast reconstruction for large data volume can be implemented by packing the subsets of projection data into the RGBA channels of GPU, performing the reconstruction chunk by chunk and combining the individual results in the end. The method is evaluated by reconstructing 3D images from computer‐simulation data and real micro‐CT data. Our results indicate that the GPU implementation can maintain original precision and speed up the reconstruction process by 110–120 times for circular cone‐beam scan, as compared to traditional CPU implementation.
Well‐Posedness of the Cauchy Problem for Hyperbolic Equations with Non‐Lipschitz Coefficients
Authors: Aliev Akbar B. , Shukurova Gulnara D.
Published: August 2009

We consider hyperbolic equations with anisotropic elliptic part and some non‐Lipschitz coefficients.
We prove well‐posedness of the corresponding Cauchy problem in some functional spaces. These functional spaces have finite smoothness with respect to variables corresponding to regular coefficients and infinite smoothness
with respect to variables corresponding to singular coefficients.
A Theoretical Investigation of the Relationship between Structural Equation Modeling and Partial Correlation in Functional MRI Effective Connectivity
Authors: Marrelec Guillaume , Benali Habib
Published: August 2009

An important field of blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) is the investigation of effective connectivity, that is, the actions that a given set of regions exert on one another. We recently proposed a data‐driven method based on the partial correlation matrix that could provide some insight regarding the pattern of functional interaction between brain regions as represented by structural equation modeling (SEM). So far, the efficiency of this approach was mostly based on empirical evidence. In this paper, we provide theoretical fundaments explaining why and in what measure structural equation modeling and partial correlations are related. This gives better insight regarding what parts of SEM can be retrieved by partial correlation analysis and what remains inaccessible. We illustrate the different results with real data.
Unexpected Coexisting Myocardial Infarction Detected by Delayed Enhancement MRI
Authors: Gerbaud Edouard , De Clermont-Galleran Henri , Erickson Matthew , Coste Pierre , Montaudon Michel
Published: August 2009

We report a case of an unexpected coexisting anterior myocardial infarction detected by delayed enhancement MRI in a 41-year-old man following a presentation with a first episode of chest pain during inferior acute myocardial infarction. This second necrotic area was not initially suspected because there were no ECG changes in the anterior leads and the left descending coronary artery did not present any significant stenoses on emergency coronary angiography. Unrecognised myocardial infarction may carry important prognostic implications. CMR is currently the best imaging technique to detect unexpected infarcts.
Fermentation Characterization of Chinese Yam Polysaccharide and Its Effects on the Gut Microbiota of Rats
Authors: Kong X. F. , Zhang Y. Z. , Wu X. , Yin Y. L. , Tan Z. L. , Feng Y. , Yan F. Y. , Bo M. J. , Huang R. L. , Li T. J.
Published: August 2009

Rat was used to characterize Chinese Yam polysaccharides (CYPs). InExp. 1, maximum volume and rate of gas production in CYP 3-supplemented group were higher than other CYP-supplemented groups and control group, while pH values and NH3 contents in CYP 2-, CYP 3-, and CYP 4-supplemented groups were lower than control group. Contents of acetate, propionate and butyrate increased by supplementing CYP 3 or CYP 4 compared to other groups, except for glucose-supplemented group. Contents of isobutyrate for CYPs groups decreased compared to control group. CYP 3 enhanced beneficial gut microbiota, but suppressed bacterial pathogens. InExp. 2, contents of acetate and butyrate in cecal digesta of rats fed 0.25 or 0.5 g/kg CYP 3 were higher than other groups on day 7. pH values in 0.25 and 0.5 g/kg groups were lower than 1.0 g/kg group. Contents of acetate in 0.25 and 0.5 g/kg groups were greater than other 2 groups on day 21. Gut microflora in CYP 3-supplemented rats had greater diversity than non-supplemented rats. CYP 3 enriched beneficial gut microbiota, but suppressed bacterial pathogens in rat cecum. These findings suggested that CYP 3 is a good source of carbon and energy, and may improve bacterial community diversity and modulate short-chain fatty acid production in hindgut of rats.