bluuebunny/crossref_metadata_2025 huggingface dataset:
Fission Track Dating of Authigenic Quartz in Red Weathering Crusts of Carbonate Rocks in Guizhou Province
Authors: Xiuming LIU , Shijie WANG , Feng ZHANG
Published: February 2012

Abstract  The Cenozoic evolution history of Guizhou Province, which is located on the southeastern flank of the Qinghai‐Tibet Plateau, is unclear because of the lack of sedimentation records. The red weathering crusts widespread on the Yunnan‐Guizhou Plateau may bear critical information about their evolution history. This work firstly determined the ages of four red weathering crusts in eastern, central and northern Guizhou. The material used in fission track dating is well‐crystallized quartz occurring in many in‐situ weathering crusts of carbonate rocks. The results showed that the fission track ages of quartz vary over a wide range from 1 to 25 Ma in the four profiles, significantly younger than the ages of the Triassic and Cambrian parent rocks. In combination with the evolution history of the regional geology during the period from 25 to 1 Ma, the ages of quartz can exclude the possibility that the origin of quartz has nothing to do with primary clastic minerals in parent rocks, authigenesis during diagenesis and hydrothermal precipitation or replacement by volcanic activities. It is deduced that the well‐crystallized quartz was precipitated from Si‐rich weathering fluids during the weathering process of carbonate rocks. The recorded ages of quartz from the four profiles are consistent with the episodes of the planauon surfaces on the Qinghai‐Tibet Plateau, the forming stages of red soil in the tropics of South China, the tectonically stable periods in Guizhou, and the ages of weathering in other parts of the world during the Cenozoic era. That is to say, the ages of authigenic quartz dated by the fission track method are well feasible and credible.
Taxonomy and Stratigraphy of Late Mesozoic Anurans and Urodeles from China
Authors: Yuan WANG
Published: February 2012

Abstract  Three anurans (Callobatrachus sanyanensis, Liaobatrachus grabaui, Mesophryne beipiaoensis) and six urodeles (Laccotriton subsolanus, Liaoxitriton zhongjiani, Jeholotriton paradoxus, Sinerpeton fengshanensis, Chunerpeton tianyiensis, Liaoxitriton daohugouensis) are reported from the late Mesozoic tuff‐interbedded lacustrine deposits (mostly of the Jehol Group) in northeastern China. They document the first discovery of Chinese Mesozoic lissamphibians, and their old geological age, superb preservation condition, and large taxonomic diversity are unique compared with other findings worldwide. The anurans occupy a higher evolutionary position than typical Jurassic taxa, supporting a post‐Late Jurassic age of the fossil horizons. The urodeles all have unicapitate ribs, suggesting an evolutionary grade at the cryptobranchoid level, and are advanced in osteological features over non‐urodeles from the Middle and Upper Jurassic in England and Central Asia. Some urodeles (Jeholotriton and Chunerpeton) exhibit neotenic features, representing the earliest occurrence among such findings. Six fossil horizons are recognized for the known Chinese Mesozoic anurans and urodeles: the Daohugou fossil bed, the Dabeigou Formation, the Lujiatun Bed, Jianshangou Bed and Dawangzhangzi Bed of the Yixian Formation, and the Jiufotang Formation. As implied from the osteological and phylogenetical studies, the geological age of these anurans and urodeles is the Early Cretaceous.
Conodont Biostratigraphy of the Middle Cambrian through Lowermost Ordovician in Hunan, South China
Authors: Xiping DONG , REPETSKI John E. , BERGSTRÖM Stig M.
Published: February 2012

Abstract  Since 1985, samples with a total weight of more than 14,000 kg, mainly from three key sections in western and northwestern Hunan, South China, have been processed for conodonts. In strata older than the late Late Cambrian paraconodonts have proved useful for stratigraphic subdivision and correlation. Thirteen conodont zones are proposed in the Middle Cambrian through lowermost Ordovician. The correlation between these zones and those of North China, western U. S.A., western Newfoundland, Canada, and Iran is discussed. In ascending order, these 13 zones are as follows: The Gapparodus bisulcatus‐Westergaardodina brevidens Zone, Shandongodus priscus‐Hunanognathus tricuspidatus Zone, Westergaardodina quadrata Zone, Westergaardodina matsushitai‐W. grandidens Zone, Westergaardodina lui‐W. ani Zone, Westergaardodina cf. calix‐Prooneotodus rotundatus Zone, Proconodontus tenuiserratus Zone, Proconodontus Zone, Eoconodontus Zone, Cordylodus proavus Zone, Cordylodus intermedius Zone, Cordylodus lindstromi Zone, and Cordylodus angulatus Zone (lower part). The Westergaardodina lui‐W. ani and Westergaardodina cf. calix‐Prooneotodus rotundatus Zones replace the Westergaardodina proligula and Westergaardodina cf. behrae‐Prooneotodus rotundatus Zones, respectively, in the lowermost Upper Cambrian. Two new species (Westergaardodina lui and Westergaardodina ani) and one conditionally identified species (Westergaardodina cf. calix) are described.
Panorama of the Opening‐Closing Tectonics Theory in China
Authors: Weiran YANG , Jiandong ZHENG
Published: February 2012

Abstract  The opening‐closing tectonics theory, a theory about opening‐closing tectonics, is a viewpoint regarding geotectonics suggested by a group of Chinese scientists. Opening and closing are two basic geological movements, which may result in a series of structures. The highest level of opening is the appearance of oceans and the highest level of closing is the consolidation of continents. Based on field investigations, the authors consider that identifying the marks of opening‐closing tectonics is the basis of the issue and classifying the types of opening‐closing tectonics is the key of the issue. This paper briefly discusses the substance and the future of the study on the opening‐closing tectonics in China. The authors hope to share relevant information with geoscientists in the world in this field.
Surplus Space Method: A New Numerical Model for Prediction of Shallow‐seated Magmatic Bodies
Authors: Jun DENG , Dinghua HUANG , Qingfei WANG , Li WAN , Lingqing YAO , Bangfei GAO , Yan Liu
Published: February 2012

Abstract  Based on the data of field measurement and drilling in the Tongling area, a series of numerical simulations are carried out by using the “Surplus Space Method” (SSM), which is first put forward in this paper and applied to predict the shallow‐seated magmatic bodies. The results of the numerical simulations show the existence and the 3‐D shape of a conical magmatic structure at a depth of −1000 m beneath the center of the area: its top offsets southwards and bifurcates to several branches, while its lower part stretches northeastwards and contracts rapidly to a point at about −1000 m depth. This point is reckoned to be a “sink” of magma system, transferring ore materials and heat energy from the deep magma chamber to the sub‐surface apophyses. The preliminary application of the SSM proves that it may be developed as a new detection means for determining the existence of shallow‐seated magmatic bodies and analyzing their three‐dimensional features.
Speleogenesis of Selected Caves beneath the Lunan Shilin and Caves of Fenglin Karst in Qiubei, Yunnan
Authors: ŠEBELA Stanka , SLABE Tadej , Hong LIU , PRUNER Petr
Published: February 2012

Abstract  Yunnan is famous for its attractive karst landscapes especially shilins, fengcong and fenglin. The development of caves beneath the shilins in the vicinity of Lunan is closely connected with the formation of shilins. Most of the waters percolating through shilins run through the caves beneath them and are responsible for their formation. The study of cave speleogenesis deepens knowledge about both the development of shilins and karst structure. In the vicinity of the Lunan Shilin, speleological, morphological and structural geological studies of four karst caves have been accomplished. At Puzhehei, Qiubei, which is characterised by numerous fenglin, fengcong and caves, speleological and morphological studies have been performed. Cave sediments for paleomagnetic analyses have been taken from all studied areas (samples CH 1–9). Karst caves in SE Yunnan are probably much older than the age of the cave sediments (<780,000 years B.P.). The studied areas are located in the vicinity of the Xiaojiang fault (N‐S direction) and the Red River fault (NW‐SE direction). The general directions of both active faults are assumed to influence the direction of the most frequent fissures as well as the cave passages near the Lunan Shilin. The Xiaojiang fault more strongly influences cave passage orientation, while the more distant Red River fault most strongly influences fissure orientation.
Role of naofen in apoptosis of hepatocytes induced by lipopolysaccharide through mitochondrial signaling in rats
Authors: Fan Jun‐Hua , Feng Guo‐Gang , Huang Lei , Tsunekawa Koji , Honda Takashi , Katano Yoshiaki , Hirooka Yoshiki , Goto Hidemi , Kandatsu Nobuhisa , Ando Kazuo , Fujiwara Yoshihiro , Koide Tatsuro , Okada Shoshiro , Ishikawa Naohisa
Published: February 2012

Aim:  Lipopolysaccharide (LPS) causes apoptosis of hepatocytes, which is probably mediated by inflammatory substances released from Kupffer cells (KCs). Recently, we have reported that naofen, a newly found intracellular WD40‐repeat protein, has a role in inducing the apoptosis in HEK293 cells. Hence, the present study was undertaken to investigate a role of naofen in the LPS‐induced apoptosis of rat hepatocytes.

Methods:  Rats were treated with i.v. injections of LPS, and livers were extirpated to evaluate expression of naofen and apoptosis. In in vitro experiments, hepatocytes and KCs were separately isolated from rat livers. The incubation medium for KCs treated with LPS (KC‐CM) was used for hepatocyte culture.

Results:  Intravenous injections of LPS enhanced the expression of naofen in the livers. Livers showed terminal deoxynucleotidyl transferase‐mediated dUTP nick end labeling (TUNEL)‐positive staining, and elevated caspase‐3 activity. In isolated KCs or hepatocytes, LPS hardly affected naofen expression and caspase‐3 activity, whereas incubation of hepatocytes with KC‐CM enhanced both naofen expression and caspase‐3 activation. Transfection of hepatocyte with naofen siRNA prevented such effects of KC‐CM, and clearly eliminated KC‐CM‐induced reduction of Bcl‐2 and Bcl‐xL. In contrast, overexpression of naofen in hepatocytes downregulated Bcl‐2 and Bcl‐xL, released cytochrome c from mitochondria, and activated caspase‐3.

Conclusion:  These results indicate that LPS may induce the hepatic apoptosis in association with enhanced naofen expression, and that naofen may mediate the activation of caspase‐3 through downregulating the Bcl‐2 and Bcl‐xL expression, and releasing cytochrome c from mitochondria to cytoplasm.
Diagnosis and non‐surgical periodontal management in congenital afibrinogenemia: report of a rare case
Authors: Gadagi Jayaprakash S. , Chava Vijay K.
Published: February 2012

Medical records have an important role in the diagnosis and planning treatment modalities of periodontal diseases. Surgical periodontal procedures can pose severe complications if the underlying systemic condition is not recorded. To substantiate this, we present a rare case of afibrinogenemia that was reported to the Department of Periodontics, Narayana Dental College, Nellore, India. The present case report gives details of fibrinogen disorder and the dental management of such cases.
The association of 2‐year‐old training milestones with career length and racing success in a sample of Thoroughbred horses in New Zealand
Authors: TANNER J. C. , ROGERS C. W. , FIRTH E. C.
Published: February 2012

Reasons for performing study:There is increasing evidence that exercise early in life has a positive effect on musculoskeletal health. At present, there is little whole population research investigating the effect of racing as 2‐year‐olds on future racing career.

Objectives:To investigate the association between attaining training milestones as 2‐year‐olds with length of career and racing success in Thoroughbred horses in New Zealand.

Methods:Retrospective data were obtained of the 2001/02‐born Thoroughbred foal crop. The 3 training milestones were: registered with a trainer, trialled and raced. The association of the training milestones with career length was measured using the outcomes: number of race starts and number of years raced, in a Cox regression model. Logistic regression models analysed the association of the training milestones with the outcomes: won or placed in a race. Linear regression was performed to assess the association of training milestones with total career earnings.

Results:Of 4683 horses in the population; 3152 horses were registered with a trainer, 2661 horses trialled and 2109 horses raced. Horses that raced as 2‐year‐olds had significantly (P<0.001) more race starts than those first raced as 3‐year‐olds or older, this was also true when the 2‐year‐old year data were omitted. Horses that raced as 2‐year‐olds had significantly (P<0.001) more years racing. Horses registered with a trainer, trialled or raced as 2‐year‐olds were more likely to have won or been placed in a race than those that achieved the milestones as 3‐year‐olds or older. Horses that first trialled and raced as 2‐year‐olds had greater total earnings than those that first trialled or raced at a later age.

Conclusions and potential relevance:Two‐year‐old training milestones had a strong association with positive racing career outcomes. Horses in training or racing as 2‐year‐olds may have better musculoskeletal health throughout life than horses that are first in training or racing at a later age.
Perspective Depth Extraction of Points on a Surface Under an Instantaneous Rigid Body Transformation
Authors: Bergström Per
Published: February 2012

We consider the computational problem of finding the point in 3D-space on a transformed surface corresponding to a coordinate pair given in a perspective mapping. The transformation is a rigid body transformation that is assumed to be small and vary. Initially, it is unknown but when it becomes known, the output must be accurate and quickly returned. Therefore, the computations are adapted for those conditions. Preprocessed shape information about the surface is computed in a perspective mapping where the surface is in an original position. We are discussing algorithms for solving the considered problem.
Thermo-Mechanical Contact and Micro-Wear in Head Disk Interface
Authors: Lee Sungae , Yeo Chang-Dong
Published: February 2012

Thermo-mechanical contact and micro-wear of head disk interface (HDI) are investigated using the improved HDI contact model and theories of frictional heat generation and heat transfer. In analytical simulations, dynamic contact parameters such as material properties, sliding velocity, and surface interference are based on actual HDI design and operation. The resulting contact pressure and temperature distribution show that the micro-wear on the carbon film of a head slider would be significantly attributed to the degradation of carbon material caused by frictional heat generation during sliding contact.
Elasto-Aerodynamic Lubrication Analysis of a Self-Acting Foil Air Journal Bearing
Authors: Bensouilah Hamza , Lahmar Mustapha , Bou-Sai¨d Benyebka
Published: February 2012

Most of elasto-aerodynamic approaches under dynamic conditions proposed in the technical literature include only the static pressure induced deformation of foils. This paper presents a theoretical investigation on the effects of both static and dynamic deformations of the foils on the dynamic performance characteristics and stability of a self-acting air foil journal bearing operating under small harmonic vibrations. To take into account the dynamic deformations of foils, the perturbation method is used for determining the gas-film stiffness and damping coefficients for given values of excitation frequency, compressibility number, and compliance factor of the bump foil. The nonlinear stationary Reynolds’ equation is solved by means of the Galerkin’s finite element formulation while the finite differences method are used to solve the first order complex dynamic equations resulting from the perturbation of the transient compressible Reynolds’ equation. It was found that the dynamic properties and stability of the compliant finite length journal bearing are significantly affected by the compliance of foils especially when the dynamic deformation of foils is considered in addition to the static one by applying the principle of superposition.
Influences of Gases on the Tribological Properties of Pure Iron
Authors: Fukuda Kanao , Sugimura Joichi
Published: February 2012

In this study, trace oxygen and water as impurities in experimental gas environments were reduced to less than 10 ppb to eliminate their influences on the tribological properties. A pin-on-disk apparatus in an ultra-high vacuum vessel equipped with a gas filtering system enabled pure experimental gas environments. Dry friction tests clarified that the tribological properties of pure iron in ultra-high vacuum and argon were similar to each other. On the other hand, friction coefficients obtained in hydrogen and nitrogen were considerably lower than those obtained in ultra-high vacuum and argon. Specific wear rates of pin and disk were close to each other in ultra-high vacuum, argon and hydrogen while those took very different values in nitrogen. Hydrogen influenced the tribological properties of pure iron to some extent but the influences were not as much as that of nitrogen.
Thermohydrodynamic Analysis of Journal Bearing Operating Under Nanolubricants
Authors: Nair K. Prabhakaran , Rajendra Kumar P. K. , Babu K. Sreedhar
Published: February 2012

The static performance characteristics of thermo hydrodynamic journal bearing operating under lubricant Veedol SAE 15W 40 multi grade engine oil with CuO, CeO2 and Al2O3 nanoparticles are presented. These static performance characteristics mainly depend on the viscosity of the lubricant. The addition of nano particles on commercially available lubricant may enhance the viscosity of lubricant and in turn changes the performance characteristics. In the proposed work CuO, CeO2 and Al2O3 nano particles are used with commercial lubricant Veedol SAE 15W 40 multi grade engine oil. To obtain pressure and temperature distribution, modified Reynolds and energy equations are used and these equations are solved by using the powerful numerical technique, Finite Element Method. An iterative procedure is used to establish the film extent. The static performance characteristics in terms of load capacity, attitude angle, end leakage and friction force are evaluated when the bearing operates under nanolubricants for the following cases. 1. Isoviscous; 2. Thermoviscous.
Microstructure analysis of plasma enhanced atomic layer deposition-grown mixed-phase RuTaN barrier for seedless copper electrodeposition
Authors: Chakraborty Tonmoy , Eisenbraun Eric T.
Published: February 2012

Plasma enhanced atomic layer deposition (PEALD)-grown mixed phase RuTaN films has been studied as a direct plate material for Cu electroplating within interconnects. It was seen that these liners behaved as excellent Cu diffusion barrier and could be scaled down to sub-5 nm thicknesses. High resolution TEM based structural analysis of these films showed islands of Ru surrounded by amorphous region. The selected area electron diffraction pattern corresponds to the hcp phase of Ru with (101) as the primary crystallographic orientation. Scanning tunneling microscopy and atomic force microscopy suggested the Volmer–Weber growth mechanism of these liners. A series of electroplating experiments with various plating current density and time showed that a uniform bottom-up filling could be achieved in trenches with RuTaN as direct plate liners. Trenches with aspect-ratio as high as 10 could be filled uniformly. The conformality of the PEALD RuTaN process within the trenches was also found to be very promising with step-coverage over 85%.
Routine pre-procedure laboratory testing for patients undergoing outpatient cerebral angiography is not indicated
Authors: Rai Ansaar T , Domico Jennifer
Published: February 2012

Background

Cerebral angiography is a routine low-risk procedure. Laboratory testing is performed in almost all patients. Some testing may be warranted in selected patients but can also result in delays in performing the procedure.

Purpose

To determine if routine pre-procedure testing for outpatient cerebral angiography is necessary.

Methods

447 patients who underwent outpatient cerebral angiography were reviewed. The tests were evaluated for any abnormality, correlation of the abnormality with underlying diseases and for any impact that these tests may have on the safety of the procedure. Only tests performed at our institution were analyzed. All instances of any hospital/physician visit related to the procedure were recorded.

Results

A low hemoglobin, hematocrit and platelet count was seen in 3.5%, 1.8% and 0.1% of patients, respectively. These were marginally outside the reference range and not sufficiently abnormal to indicate underlying disease or to affect the procedure. An elevated prothrombin time/international normalized ratio was seen in 4.5% of patients and this was associated with warfarin use (p<0.0001). About 15% of the patients had a disturbance in renal function. An elevated creatinine was associated with diabetes (OR 3.2, 95% CI 1.8 to 5.7, p=0.0001) and hypertension (OR 4.4, 95% CI 2.1 to 9.2, p<0.0001). Cerebral angiography was performed on these patients with appropriate renal protective measures and no cases of acute renal failure secondary to contrast administration were documented.

Conclusion

The incidence of abnormal testing in patients undergoing outpatient cerebral angiography is very low. These results and evidence in the literature suggest that the majority of patients undergoing cerebral angiography do not require any pre-procedure testing. Assessment of renal function using the estimated glomerular filtration rate in high-risk patients only is, however, warranted.
ON CURVATURE PROPERTIES OF CERTAIN QUASI-EINSTEIN HYPERSURFACES
Authors: DESZCZ RYSZARD , HOTLOŚ MARIAN , ṢENTÜRK ZERRIN
Published: February 2012

It is known that the Cartan hypersurfaces of dimension 6, 12 or 24 are non-quasi-Einstein, non-pseudosymmetric, Ricci-pseudosymmetric manifolds. In this paper we investigate quasi-Einstein hypersurfaces in semi-Riemannian space forms satisfying some Walker type identity. Among other things we prove that such hypersurfaces are Ricci-pseudosymmetric manifolds. Using certain result of Magid we construct an example of a quasi-Einstein non-pseudosymmetric Ricci-pseudosymmetric warped product which locally can be realized as a hypersurface in a semi-Riemannian space of constant curvature. In our opinion it is a first example of a hypersurface having the mentioned properties.
MULTISCALE MODELING OF POLYMER/CLAY NANOCOMPOSITES
Authors: PEREIRA SIMÃO PEDRO , SCOCCHI GIULIO , TOTH RADOVAN , POSOCCO PAOLA , NIETO DANIEL R. , PRICL SABRINA , FERMEGLIA MAURIZIO
Published: February 2012

Multiscale molecular modeling (M3) is applied in many fields of material science, but it is particularly important in the polymer science, due to the wide range of phenomena occurring at different scales which influence the ultimate properties of the materials. In this context, M3 plays a crucial role in the design of new materials whose properties are infiuenced by the structure at nanoscale. In this work we present the application of a multiscale molecular modeling procedure to characterize polymer/clay nanocomposites obtained with full/partial dispersion of nanofillers in a polymer. This approach relies on a step-by step message-passing technique from atomistic to mesoscale to finite element level; thus, computer simulations at all scales are completely integrated and the calculated results are compared to available experimental evidences. In details, nine polymer nanocomposite systems have been studied by different molecular modeling methods, such as atomistic Molecular Mechanics and Molecular Dynamics, the mesoscale Dissipative Particles Dynamics and the macroscale Finite Element Method. The entire computational procedure has been applied to a number of diverse polymer nanocomposite systems based on montmorillonite as clay and different clay surface modifiers, and their mechanical, thermal and barrier properties have been predicted in agreement with the available experimental data.
Severe hypoxia affects exercise performance independently of afferent feedback and peripheral fatigue
Authors: Millet Guillaume Y. , Muthalib Makii , Jubeau Marc , Laursen Paul B. , Nosaka Kazunori
Published: February 2012

To test the hypothesis that hypoxia centrally affects performance independently of afferent feedback and peripheral fatigue, we conducted two experiments under complete vascular occlusion of the exercising muscle under different systemic O2 environmental conditions. In experiment 1, 12 subjects performed repeated submaximal isometric contractions of the elbow flexor to exhaustion (RCTE) with inspired O2 fraction fixed at 9% (severe hypoxia, SevHyp), 14% (moderate hypoxia, ModHyp), 21% (normoxia, Norm), or 30% (hyperoxia, Hyper). The number of contractions (performance), muscle (biceps brachii), and prefrontal near-infrared spectroscopy (NIRS) parameters and high-frequency paired-pulse (PS100) evoked responses to electrical muscle stimulation were monitored. In experiment 2, 10 subjects performed another RCTE in SevHyp and Norm conditions in which the number of contractions, biceps brachii electromyography responses to electrical nerve stimulation (M wave), and transcranial magnetic stimulation responses (motor-evoked potentials, MEP, and cortical silent period, CSP) were recorded. Performance during RCTE was significantly reduced by 10–15% in SevHyp (arterial O2 saturation, SpO2 = ∼75%) compared with ModHyp (SpO2 = ∼90%) or Norm/Hyper (SpO2 > 97%). Performance reduction in SevHyp occurred despite similar 1) metabolic (muscle NIRS parameters) and functional (changes in PS100 and M wave) muscle states and 2) MEP and CSP responses, suggesting comparable corticospinal excitability and spinal and cortical inhibition between SevHyp and Norm. It is concluded that, in SevHyp, performance and central drive can be altered independently of afferent feedback and peripheral fatigue. It is concluded that submaximal performance in SevHyp is partly reduced by a mechanism related directly to brain oxygenation.
Neuroprotective role of the TREK-1 channel in decompression sickness
Authors: Vallee Nicolas , Meckler Cédric , Risso Jean-Jacques , Blatteau Jean-Eric
Published: February 2012

Nitrogen supersaturation and bubble formation can occur in the vascular system after diving, leading to death and nervous disorders from decompression sickness (DCS). Bubbles alter the vascular endothelium, activate platelets, and lead to focal ischemia with neurological damage mediated by the mechanosensitive TREK-1 neuronal potassium ion channel that sets pre- and postsynaptic resting membrane potentials. We report a neuroprotective effect associated with TREK-1. C57Bl6 mice were subjected to decompression from a simulated 90 msw dive. Of 143 mice that were wild type (WT) for TREK-1, 51.7% showed no DCS, 27.3% failed a grip test, and 21.0% died. Of 88 TREK-1 knockouts (KO), 26.1% showed no DCS, 42.0% failed a grip test, and 31.8% died. Mice that did not express TREK-1 had lower DCS resistance and were more likely to develop neurological symptoms. We conclude that the TREK-1 potassium channel was neuroprotective for DCS.
Coronary collaterals provide a constant scaffold effect on the left ventricle and limit ischemic left ventricular dysfunction in humans
Authors: Hoole Stephen P. , White Paul A. , Read Philip A. , Heck Patrick M. , West Nick E. , O'Sullivan Michael , Dutka David P.
Published: February 2012

Coronary collaterals preserve left ventricular (LV) function during coronary occlusion by reducing myocardial ischemia and may directly influence LV compliance. We aimed to re-evaluate the relationship between coronary collaterals, measured quantitatively with a pressure wire, and simultaneously recorded LV contractility from conductance catheter data during percutaneous coronary intervention (PCI) in humans. Twenty-five patients with normal LV function awaiting PCI were recruited. Pressure-derived collateral flow index (CFI p): CFI p = (P w − P v)/(P a − P v) was calculated from pressure distal to coronary balloon occlusion (P w), central venous pressure (P v), and aortic pressure (P a). CFI p was compared with the changes in simultaneously recorded LV end-diastolic pressure (ΔLVEDP), end-diastolic volume, maximum rate of rise in pressure (ΔLVdP/dtmax; systolic function), and time constant of isovolumic relaxation (ΔLV τ; diastolic function), measured by a LV cavity conductance catheter. Measurements were recorded at baseline and following a 1-min coronary occlusion and were duplicated after a 30-min recovery period. There was significant LV diastolic dysfunction following coronary occlusion (ΔLVEDP: +24.5%, P < 0.0001; and ΔLV τ: +20.0%, P < 0.0001), which inversely correlated with CFI p (ΔLVEDP vs. CFI p: r = −0.54, P < 0.0001; ΔLV τ vs. CFI p: r = −0.46, P = 0.0009). Subjects with fewer collaterals had lower LVEDP at baseline (r = 0.33, P = 0.02). CFI p was inversely related to the coronary stenosis pressure gradient at rest (r = −0.31, P = 0.03). Collaterals exert a direct hemodynamic effect on the ventricle and attenuate ischemic LV diastolic dysfunction during coronary occlusion. Vessels with lesions of greater hemodynamic significance have better collateral supply.
Immune Thrombocytopenia in Patients with Chronic Lymphocytic Leukemia Is Associated with Stereotyped B-cell Receptors
Authors: Visco Carlo , Maura Francesco , Tuana Giacomo , Agnelli Luca , Lionetti Marta , Fabris Sonia , Novella Elisabetta , Giaretta Ilaria , Reda Gianluigi , Barcellini Wilma , Baldini Luca , Neri Antonino , Rodeghiero Francesco , Cortelezzi Agostino
Published: February 2012

Purpose: To assess biologic features related to the development of immune thrombocytopenia (ITP) in patients with chronic lymphocytic leukemia (CLL).

Experimental Design: We retrospectively analyzed 463 patients with CLL with available immunoglobulin heavy-chain variable (IGHV) gene status and B-cell receptor (BCR) configuration [heavy-chain complementary-determining region 3 (HCDR3)], of whom thirty-six developed ITP, according to previously defined criteria. Most of them had available cytogenetic analysis.

Results: We observed a significant association between ITP occurrence and IGHV unmutated gene status (P < 0.0001), unfavorable cytogenetic lesions (P = 0.005), and stereotyped HCDR3 (P = 0.006). The more frequent stereotyped HCDR3 subsets were #1 (IGHV1-5-7/IGHD6-19/IGHJ4; 16 of 16 unmutated) and #7 (IGHV1-69 or IGHV3-30/IGHD3-3/IGHJ6; 13 of 13 unmutated), both being significantly more represented among patients developing ITP (P = 0.003 and P = 0.001, respectively). Moreover, restricting the analysis to unmutated patients, subset #7 confirmed its independent significant association with the occurrence of ITP (P = 0.013). Both unmutated IGHV mutational status, del(11)(q23) and stereotyped BCR were significantly associated with shorter time to ITP development (P < 0.0001, P = 0.02, and P = 0.005, respectively) than other patients.

Conclusion: Our data suggest that patients with CLL and peculiar BCR conformations are at higher risk of developing secondary ITP and that stereotyped BCR may be involved in the pathogenesis of this complication. Clin Cancer Res; 18(7); 1870–8. ©2012 AACR.
Antimicrobial RNases in Cutaneous Defense
Authors: Simanski Maren , Köten Bente , Schröder Jens-Michael , Gläser Regine , Harder Jürgen
Published: February 2012

Antimicrobial proteins (AMP) are small endogenous proteins which are capable of rapidly inactivating microorganisms at low micro- and nanomolar concentrations. Their significance in host defense is reflected by their wide distribution in nature. Several AMP have been isolated from human skin, and there is increasing evidence that AMP may play an important role in cutaneous defense. One important human AMP class comprises several antimicrobial members of the RNase A superfamily. Of these, two members, RNase 7 and RNase 5, have been implicated in cutaneous defense. This review gives an overview about our current knowledge on the potential role of RNase 7 and RNase 5 in protecting human skin from infection.
A 380-kb Duplication in 7p22.3 Encompassing the LFNG Gene in a Boy with Asperger Syndrome
Authors: Vulto-van Silfhout A.T. , de Brouwer A.P.M. , de Leeuw N. , Obihara C.C. , Brunner H.G. , de Vries B.B.A.
Published: February 2012

De novo genomic aberrations are considered an important cause of autism spectrum disorders. We describe a de novo 380-kb gain in band p22.3 of chromosome 7 in a patient with Asperger syndrome. This duplicated region contains 9 genes including the LNFG gene that is an important regulator of NOTCH signaling. We suggest that this copy number variation has been a contributive factor to the occurrence of Asperger syndrome in this patient.
Three Potential Mechanisms for Failure of High Intensity Focused Ultrasound Ablation in Cardiac Tissue
Authors: Laughner Jacob I. , Sulkin Matthew S. , Wu Ziqi , Deng Cheri X. , Efimov Igor R.
Published: February 2012

Background—

High intensity focused ultrasound (HIFU) has been introduced for treatment of cardiac arrhythmias because it offers the ability to create rapid tissue modification in confined volumes without directly contacting the myocardium. In spite of the benefits of HIFU, a number of limitations have been reported, which hindered its clinical adoption.

Methods and Results—

In this study, we used a multimodal approach to evaluate thermal and nonthermal effects of HIFU in cardiac ablation. We designed a computer controlled system capable of simultaneous fluorescence mapping and HIFU ablation. Using this system, linear lesions were created in isolated rabbit atria (n=6), and point lesions were created in the ventricles of whole-heart (n=6) preparations by applying HIFU at clinical doses (4–16 W). Additionally, we evaluate the gap size in ablation lines necessary for conduction in atrial preparations (n=4). The voltage sensitive dye di-4-ANEPPS was used to assess functional damage produced by HIFU. Optical coherence tomography and general histology were used to evaluate lesion extent. Conduction block was achieved in 1 (17%) of 6 atrial preparations with a single ablation line. Following 10 minutes of rest, 0 (0%) of 6 atrial preparations demonstrated sustained conduction block from a single ablation line. Tissue displacement of 1 to 3 mm was observed during HIFU application due to acoustic radiation force along the lesion line. Additionally, excessive acoustic pressure and high temperature from HIFU generated cavitation, causing macroscopic tissue damage. A minimum gap size of 1.5 mm was found to conduct electric activity.

Conclusions—

This study identified 3 potential mechanisms responsible for the failure of HIFU ablation in cardiac tissues. Both acoustic radiation force and acoustic cavitation, in conjunction with inconsistent thermal deposition, can increase the risk of lesion discontinuity and result in gap sizes that promote ablation failure.
High Horizontal and Vertical Resolution Limited-Area Model: Near-Surface and Wind Energy Forecast Applications
Authors: Bernier Natacha B. , Bélair Stéphane
Published: February 2012

As harvesting of wind energy grows, so does the need for improved forecasts from the surface to the top of wind turbines. To improve mesoscale forecasts of wind, temperature, and dewpoint temperature in this layer, two different approaches are examined. In the first experiment, the vertical resolution of a limited-area model with 2.5-km grid spacing (LAM-2.5 km) is significantly increased near the surface to better represent profiles in that layer. In the second experiment, prognostic variables for land and ocean surfaces are initialized using results from an external land surface model system [the Global Environmental Multiscale Surface system (GEM-Surf)] and from a regional ocean model. Results show that increasing the vertical resolution near the surface leads to improved temperature and dewpoint temperature forecasts at the surface and in the wind turbine layer. For winds, improvements are more modest, because they are limited to the gradient measured across the span of the vertical wind turbine blades. On the other hand, the replacement of operational surface analyses with high-resolution analyses obtained from GEM-Surf is found to improve summer dewpoint temperature forecasts. It is shown that changes in soil moisture analyses explain the bulk of the improved dewpoint forecasts.
Summer Land–Atmosphere Coupling Strength in the United States: Comparison among Observations, Reanalysis Data, and Numerical Models
Authors: Mei Rui , Wang Guiling
Published: February 2012

This study examines the land–atmosphere coupling strength during summer over subregions of the United States based on observations [Climate Prediction Center (CPC)–Variable Infiltration Capacity (VIC)], reanalysis data [North American Regional Reanalysis (NARR) and NCEP Climate Forecast System Reanalysis (CFSR)], and models [Community Atmosphere Model, version 3 (CAM3)–Community Land Model, version 3 (CLM3) and CAM4–CLM4]. The probability density function of conditioned correlation between soil moisture and subsequent precipitation or surface temperature during the years of large precipitation anomalies is used as a measure for the coupling strength. There are three major findings: 1) among the eight subregions (classified by land cover types), the transition zone Great Plains (and, to a lesser extent, the Midwest and Southeast) are identified as hot spots for strong land–atmosphere coupling; 2) soil moisture–precipitation coupling is weaker than soil moisture–surface temperature coupling; and 3) the coupling strength is stronger in observational and reanalysis products than in the models examined, especially in CAM4–CLM4. The conditioned correlation analysis also indicates that the coupling strength in CAM4–CLM4 is weaker than in CAM3–CLM3, which is further supported by Global Land–Atmosphere Coupling Experiments1 (GLACE1)-type experiments and attributed to changes in CAM rather than modifications in CLM. Contrary to suggestions in previous studies, CAM–CLM models do not seem to overestimate the land–atmosphere coupling strength.
Retrieving Winds in the Surface Layer over Land Using an Airborne Doppler Lidar
Authors: Godwin K. S. , De Wekker S. F. J. , Emmitt G. D.
Published: February 2012

Airborne Doppler wind lidars are increasingly being used to measure winds in the lower atmosphere at higher spatial resolution than ever before. However, wind retrieval in the range gates closest to the earth’s surface remains problematic. When a laser beam from a nadir-pointing airborne Doppler wind lidar intercepts the ground, the return signal from the ground mixes with the windblown aerosol signal. As a result, winds in a layer adjacent to the surface are often unreliable and removed from wind profiles. This paper describes the problem in detail and discusses a two-step approach to improve near-surface wind retrievals. The two-step approach involves removing high-intensity ground returns and identifying and tracking aerosol radial velocities in the layer affected by ground interference. Using this approach, it is shown that additional range gates closer to the surface can be obtained, thereby further enhancing the potential of airborne Doppler lidar in atmospheric applications. The benefits of the two-step approach are demonstrated using measurements acquired over the Salinas Valley in central California. The additional range gates reveal details of the wind field that were previously not quantified with the original approach, such as a pronounced near-surface wind speed maximum.
Case Study of a Barrier Wind Corner Jet off the Coast of the Prince Olav Mountains, Antarctica
Authors: Nigro Melissa A. , Cassano John J. , Lazzara Matthew A. , Keller Linda M.
Published: February 2012

The Ross Ice Shelf airstream (RAS) is a barrier parallel flow along the base of the Transantarctic Mountains. Previous research has hypothesized that a combination of katabatic flow, barrier winds, and mesoscale and synoptic-scale cyclones drive the RAS. Within the RAS, an area of maximum wind speed is located to the northwest of the protruding Prince Olav Mountains. In this region, the Sabrina automatic weather station (AWS) observed a September 2009 high wind event with wind speeds in excess of 20 m s−1 for nearly 35 h. The following case study uses in situ AWS observations and output from the Antarctic Mesoscale Prediction System to demonstrate that the strong wind speeds during this event were caused by a combination of various forcing mechanisms, including katabatic winds, barrier winds, a surface mesocyclone over the Ross Ice Shelf, an upper-level ridge over the southern tip of the Ross Ice Shelf, and topographic influences from the Prince Olav Mountains. These forcing mechanisms induced a barrier wind corner jet to the northwest of the Prince Olav Mountains, explaining the maximum wind speeds observed in this region. The RAS wind speeds were strong enough to induce two additional barrier wind corner jets to the northwest of the Prince Olav Mountains, resulting in a triple barrier wind corner jet along the base of the Transantarctic Mountains.
Radial Artery Sterile Granulomatous Reaction Secondary to Hydrophilic-Coated Sheath Used for Transradial Cardiac Catheterization
Authors: De Leon Dexter , Swank Gary , Mirza M. Ayoub
Published: February 2012

Radial access has lower risk of vascular complication for cardiac catheterization and is rapidly replacing femoral access. There are few unique complications associated with this approach. We present 3 cases of sterile granulomatous reaction associated with a specific hydrophilic radial sheath and possibly contribution by radial wrist band [TR band; Terumo Medical used for hemostasis after sheath removal (2101 cotton tail lane somerset NJ, USA)]. Awareness of this association will help clinicians use appropriate preventive measures.
Clinical Usefulness of Assessment of Ankle–Brachial Index and Carotid Stenosis in Type 2 Diabetic Population—Three-Year Cohort Follow-Up of Mortality
Authors: Bosevski Marijan , Peovska Irena
Published: February 2012

We evaluated the clinical usefulness of assessing the ankle–brachial index (ABI) and carotid stenosis (CS) in a type 2 diabetic population. Patients with type 2 diabetes and coronary artery disease (n = 265) were enrolled in a prospective 3-year cohort study. The cardiovascular mortality rate was 8.7% (23 of 265) during the 36-month study and the all-cause mortality rate was 9.5% (25 of 265). Multivariate logistic regression analysis revealed that age (odds ratio [OR] 2.09), hypertension (OR 7.99), obesity (OR 4.86), internal CS (OR 262.17), and Gensini score (OR 1.15) were independent predictors of cardiovascular mortality. Mean ABI value (OR 0.15) was the only predictor of all-cause mortality in this population. The ABI and carotid artery ultrasound have independent prognostic value in a type 2 diabetic population.
Optimal tuning of multi-machine power system stabilizers by the Queen-Bee Evolution technique
Authors: Linda M Mary , Nair N Kesavan
Published: February 2012

A Queen-Bee Evolution-based tuning of a multi-machine power system stabilizer, which aims at enhancing the damping of the system over a wide range of operating conditions, is introduced in this paper. The basic components of this study are modeled by IEEE Model 1.1 and Heffron–Philips constants, considering the external resistance but neglecting the armature resistance. The problem is then formulated as a constrained multi-objective optimization problem. For investigation purposes, two different test systems are considered. The non-linear time domain simulations of the proposed power system stabilizer are compared with that based on the conventional approach power system stabilizer. The overall transfer function and the characteristic equation of the compensated system are derived from the single equivalent block diagram, and the nature of stability is verified by both frequency response analysis and Routh-Hurwitz (RH) criterion. Simulation results show that the proposed method motivates faster damping and leads to minimal overshoots in both speed and power angle deviations.
Prevalence of vocal problems: Speech-language pathologists’ evaluation of music and non-music teacher recordings
Authors: Hackworth Rhonda S.
Published: February 2012

The current study, a preliminary examination of whether music teachers are more susceptible to vocal problems than teachers of other subjects, asked for expert evaluation of audio recordings from licensed speech-language pathologists. Participants ( N = 41) taught music ( n = 23) or another subject ( n = 18) in either elementary ( n = 21), middle ( n = 10), or high school ( n = 10), and had a mean of 14 years’ teaching experience. Each teacher read a poem while being audio recorded. Nine licensed speech-language pathologists with a mean of 20 years’ clinical experience served as expert evaluators by listening to the 41 recordings while manipulating the Continuous Response Digital Interface (CRDI) dial. Results showed no significant differences between music and non-music teacher evaluations. The individual variations in scores showed no trends for any particular group, but rather pointed out how personal vocal hygiene (care of the voice) is for individual teachers. Suggestions for future research include ways to best help teachers manage individual vocal problems.
Neuromuscular electrical stimulation in the treatment of knee osteoarthritis: a systematic review and meta-analysis
Authors: Giggins OM , Fullen BM , Coughlan GF
Published: February 2012

Objective:

To assess the effectiveness of surface neuromuscular electrical stimulation in the treatment of knee osteoarthritis.

Design:

Systematic review and meta-analysis of randomized controlled and controlled clinical trials

Methods:

Studies were identified from databases (MEDLINE, EMBASE, CINAHL, Sports Discus, PEDro and the Cochrane Library) searched to January 2011 using a battery of keywords. Two reviewers selected studies meeting inclusion criteria. The methodological quality of the included studies was assessed using the Thomas Test and the strength of the evidence was then graded using the Agency for Health Care Policy and Research guidelines. Data were pooled and meta-analyses were performed.

Results:

Nine randomized controlled trials and one controlled clinical trial, studying a total of 409 participants ( n = 395 for randomized controlled trials, and n = 14 for controlled trial) with a diagnosis of osteoarthritis were included. Inconsistent evidence (level D) was found that neuromuscular electrical stimulation has a significant impact on measures of pain, function and quadriceps femoris muscle strength in knee osteoarthritis.

Conclusion:

The role of neuromuscular electrical stimulation in the treatment of knee osteoarthritis is ambiguous. Therefore, future work is needed in this field to clearly establish the role of neuromuscular electrical stimulation in this population.