bluuebunny/crossref_metadata_2025 huggingface dataset:
Providing Memory Management Abstraction for Self‐Reconfigurable Video Processing Platforms
Authors: Ackermann Kurt Franz , Hoffmann Burghard , Indrusiak Leandro Soares , Glesner Manfred
Published: August 2009

This paper presents a concept for an SDRAM controller targeting video processing platforms with dynamically reconfigurable processing units (RPUs). A priority‐arbitration algorithm provides the required QoS and supports high bit‐rate data streaming of multiple clients. Conforming to common video data structures the controller organizes the memory in partitions, frames, lines, and pixels. The raised level of abstraction drastically reduces the complexity of clients′ addressing logic. Its uniform interface structure facilitates instantiations in systems with various clients. In addition to SDRAM controllers for regular applications, special demands of reconfigurable platforms have to be satisfied. The aim of this work is to minimize the number of required bus macros leading to relaxed place and route constraints and reducing the number of critical design paths. A suitable interface protocol is presented, and fundamental implementation issues are outlined.
Does Preoperative Weight Change Predict Postoperative Weight Loss after Laparoscopic Roux-en-Y Gastric Bypass in the Short Term?
Authors: Eisenberg Dan , Duffy Andrew J. , Bell Robert L.
Published: August 2009

Background. Many institutions mandate preoperative weight loss prior to bariatric surgery. This study examines the correlation between preoperative weight change and postoperative success following laparoscopic Roux-en-Y gastric bypass.Methods. We retrospectively studied the correlation between change in BMI before surgery and change in BMI postoperatively, using linear regression analyses and one-way ANOVA, in 256 consecutive gastric bypass patients with 1-year followup.Results. Of 256 patients, 125 lost weight preoperatively (mean % BMI), while 131 maintained or gained weight (mean +1.2% BMI). Postoperatively, there was no significant difference in percent BMI loss between the two groups (34.6% and 34.5%). The percent change in BMI preoperatively did not predict postoperative BMI change after 1 year ().Conclusions. Our study did not show any correlation between preoperative weight change and postoperative weight loss after Roux-en-Y gastric bypass. Therefore, we do not believe that potential patients should be denied bariatric surgery on the basis of their inability to lose weight preoperatively.
Targeting Sphingosine Kinase 1 Inhibits Akt Signaling, Induces Apoptosis, and Suppresses Growth of Human Glioblastoma Cells and Xenografts
Authors: Kapitonov Dmitri , Allegood Jeremy C. , Mitchell Clint , Hait Nitai C. , Almenara Jorge A. , Adams Jeffrey K. , Zipkin Robert E. , Dent Paul , Kordula Tomasz , Milstien Sheldon , Spiegel Sarah
Published: September 2009

Sphingosine-1-phosphate is a potent sphingolipid mediator of diverse processes important for brain tumors, including cell growth, survival, migration, invasion, and angiogenesis. Sphingosine kinase 1 (SphK1), one of the two isoenzymes that produce sphingosine-1-phosphate, is up-regulated in glioblastoma and has been linked to poor prognosis in patients with glioblastoma multiforme (GBM). In the present study, we found that a potent isotype-specific SphK1 inhibitor, SK1-I, suppressed growth of LN229 and U373 glioblastoma cell lines and nonestablished human GBM6 cells. SK1-I also enhanced GBM cell death and inhibited their migration and invasion. SK1-I rapidly reduced phosphorylation of Akt but had no significant effect on activation of extracellular signal-regulated kinase 1/2, another important survival pathway for GBM. Inhibition of the concomitant activation of the c-Jun-NH2-kinase pathway induced by SK1-I attenuated death of GBM cells. Importantly, SK1-I markedly reduced the tumor growth rate of glioblastoma xenografts, inducing apoptosis and reducing tumor vascularization, and enhanced the survival of mice harboring LN229 intracranial tumors. Our results support the notion that SphK1 may be an important factor in GBM and suggest that an isozyme-specific inhibitor of SphK1 deserves consideration as a new therapeutic agent for this disease. [Cancer Res 2009;69(17):6915–23]
CCAAT Enhancer Binding Protein-β Regulates Matrix Metalloproteinase-1 Expression in Interleukin-1β–Stimulated A549 Lung Carcinoma Cells
Authors: Armstrong David A. , Phelps Lauren N. , Vincenti Matthew P.
Published: September 2009

Matrix metalloproteinase-1 (MMP-1) is an inflammation-inducible neutral protease that mediates extracellular matrix remodeling and promotes tumor invasion. In this study, we examined the activation of MMP-1 gene expression in A549 lung carcinoma cells stimulated with the inflammatory cytokine interleukin-1β (IL-1β). We found that MMP-1 mRNA levels were maximal following 16 hours of IL-1β stimulation and that this correlated with the expression of the transcription factor CCAAT enhancer-binding protein-β (CEBPB). Knockdown of CEBPB expression with short hairpin RNA abrogated the expression of MMP-1, MMP-3, and MMP-10 in IL-1β–stimulated A549 cells. An established CEBP element in the MMP-1 promoter was found to be required for basal and IL-1β–induced transcription. Electrophoresis mobility shift assays showed that CEBPB binds to this promoter element maximally 16 hours after IL-1β stimulation. DNA affinity chromatography studies showed that the LAP1, LAP2, and LIP isoforms of CEBPB bind to the IL-1β–responsive CEBPB site in the MMP-1 promoter. Exogenous expression of the LAP1 and LAP2 isoforms stimulated the MMP-1 promoter, whereas LIP had no effect. Phosphorylation of CEBPB at Thr235 peaked at 16 hours in IL-1β–stimulated cells. The MEK inhibitor U0126 inhibited this phosphorylation and reduced MMP-1 gene induction. These studies establish CEBPB as an important mediator of metalloproteinase gene activation during inflammatory responses in lung cancer cells and highlight the different regulatory roles of CEBPB isoforms. (Mol Cancer Res 2009;7(9):1517–24)
Involvement of the Mitochondrial Pathway in p53-Independent Apoptosis Induced by p28GANK Knockdown in Hep3B Cells
Authors: Wang J. , Wang X.F. , Zhang L.G. , Xie S.Y. , Li Z.L. , Li Y.J. , Li H.H. , Jiao F.
Published: August 2009

It is well known that TP53 may mediate apoptosis triggered by anticancer drugs. However, accumulating evidence indicates that TP53 may be inactivated by mutations and/or deletions in about 50% of human cancers and, as such, may lead to pronounced resistance to therapeutic agents. Thus, the development of new approaches to improve the efficiency of therapeutic agents in cancer cells harboring mutant TP53 may have a significant impact on cancer treatment. It has been reported that knockdown by RNA interference (RNAi) of p28GANK (an alias of the gene PSMD10), a novel oncogene over-expressed in hepatocellular carcinoma (HCC), can induce apoptosis in HepG2, a TP53-intact HCC cell line. Because of the high frequency TP53 mutations in HCC, it is relevant to know whether p28GANK knockdown-induced apoptosis is also operational in TP53-negative HCC cells. Here, we investigated Adsip28GANK-induced apoptosis in the TP53-negative HCC cell line Hep3B. Our results indicate that p28GANK-knockdown induces the generation of reactive oxygen species (ROS), which in turn activates p38. Since p38 can signal to Bax, its activation may lead to mitochondrial transmembrane potential (Δψm) loss, cytochrome c release from mitochondria to cytosol, and caspase-9 activation, eventually triggering the mitochondrial pathway of apoptosis.
Submicroscopic Duplication of the Wolf-Hirschhorn Critical Region with a 4p Terminal Deletion
Authors: Roselló M. , Monfort S. , Orellana C. , Ferrer-Bolufer I. , Quiroga R. , Oltra S. , Martínez F.
Published: August 2009

Chromosomal rearrangements in the short arm of chromosome 4 can result in 2 different clinical entities: Wolf-Hirschhorn syndrome (WHS), characterized by severe growth delay, mental retardation, microcephaly, ‘Greek helmet’ facies, and closure defects, or partial 4p trisomy, associated with multiple congenital anomalies, mental retardation, and facial dysmorphisms. We present clinical and laboratory findings in a patient who showed a small duplication in 4p16.3 associated with a subtle terminal deletion in the same chromosomal region. GTG-banding analyses, multiplex ligation-dependent probe amplification analyses, and studies by array-based comparative genomic hybridization were performed. The results of the analyses revealed a de novo 1.3 Mb deletion of the terminal 4p and a 1.1 Mb duplication in our patient, encompassing the WHS critical region. Interestingly, this unusual duplication/deletion rearrangement results in an intermediate phenotype that shares characteristics of the WHS and the 4p trisomy syndrome. The use of novel technologies in the genetic diagnosis leads to the description of new clinical syndromes; there is a growing list of microduplication syndromes. Therefore, we propose that overexpression of candidate genes in WHS (WHSC1, WHSC2 and LETM1) due to a duplication causes a clinical entity different to both the WHS and 4p trisomy syndrome.
Molecular Cytogenetic Characterization of Two Cases with de novo Small Mosaic Supernumerary Marker Chromosomes Derived from Chromosome 16: Towards a Genotype/Phenotype Correlation
Authors: Melo J.B. , Matoso E. , Polityko A. , Saraiva J. , Backx L. , Vermeesch J.R. , Kosyakova N. , Ewers E. , Liehr T. , Carreira I.M.
Published: August 2009

Small supernumerary marker chromosomes (sSMC) derived from chromosome 16 are rare and, so far, it is not yet clear which regions of chromosome 16 are critical and have clinical consequences. We have characterized two cases with a ring-shaped sSMC derived from chromosome 16. In case A the sSMC was encountered prenatally and was characterized using centromeric fluorescence in situ hybridization (FISH) probes, subcentromere-specific multicolor FISH (subcenM-FISH), reverse FISH and array-CGH, using a full-tiling BAC array specific for chromosome 16. Case B is a postnatal case and the sSMC was characterized by centromeric FISH probes and subcenM-FISH. Our results, using molecular cytogenetics, showed that both sSMC were derived from chromosome 16, resulting in a de novo mosaic partial trisomy of chromosome 16, involving euchromatic material from 16q. Array painting, in case A, allowed the localization of the sSMC breakpoints, revealing that the sSMC comprised the 33.43–47.02 Mb region of chromosome 16 (16p11.2 to 16q12.1), a region known to harbor some protein-coding genes. In general, the phenotypic consequences of a de novo marker chromosome are difficult to assess. Molecular cytogenetics techniques are a valuable tool for the accurate identification of the origin and content of marker chromosomes, contributing to a more informed prenatal counseling and patient follow-up. Besides multicolor FISH approaches, array painting, combining microdissection and array-CGH, is very useful for mapping size and breakpoints of marker chromosomes, since sSMC are often only present in a small percentage of cells.
Chromosomal Variability among Allopatric Populations of Erythrinidae Fish Hoplias malabaricus: Mapping of Three Classes of Repetitive DNAs
Authors: Cioffi M.B. , Martins C. , Centofante L. , Jacobina U. , Bertollo L.A.C.
Published: August 2009

Karyotype and chromosomal characteristics from 3 allopatric populations of Hoplias malabaricus, cytogenetically the most studied Erythrinidae taxon, were investigated using different staining techniques (C-, Ag-, and CMA3 banding) as well as fluorescent in situ hybridization (FISH) to detect 18S rDNA, 5S rDNA, and 5SHindIII satellite DNA sites. The isolation, cloning and characterization of an 18S rDNA probe from H. malabaricus genome were also performed for the first time in order to develop a more specific probe. The 3 populations, named PR, CR, and DR, showed identical karyotypes, with 2n = 42 chromosomes composed of 11 m pairs and 10 sm pairs, without heteromorphic sex chromosomes, which characterize the populations as belonging to karyomorph A. In all populations C-positive heterochromatin was situated in the centromeric/pericentromeric regions of the chromosomes, as well as in the telomeric region of several pairs. A conspicuous proximal heterochromatic block on the long arm of pair No. 16 was the only GC-rich segment in the karyotypes. 5SHindIII satellite DNA was always mapped in the centromeric region of several chromosomes. The 18S rDNA sites were situated on the telomeric or centromeric regions, whereas the 5S rDNA showed an interstitial or proximal location in some pairs. Several chromosomes bearing these repetitive DNA sequences were shared by the 3 populations, alongside with some exclusive chromosomal markers. In this sense, population CR was the most differentiated one, including a syntenic condition for the 18S and 5S rDNA probes, as confirmed by double FISH. Thus, despite their inclusion in the same major karyotypic group, the distinct populations cannot be considered an absolute evolutionary unit, as evidenced by their inner chromosomal differentiations.
Chromosome Polymorphism and Fanconi-Like Instability in the Scarabaeid Beetle Macraspis tristis from Guadeloupe
Authors: Dutrillaux A.M. , Dutrillaux B.
Published: August 2009

The karyotype of Macraspis tristis Laporte is described. It is composed of 18 chromosomes. C-band positive heterochromatin is very abundant and is located at centromeric regions and, for some chromosomes, at telomeric regions. There is a high inter-individual chromosomal polymorphism for the presence and extension of telomeric heterochromatin. In one of the 8 specimens studied, 2 populations were observed in testicular cells. Besides groups of normal metaphases, other groups displayed multiple chromatid and chromosome alterations such as breaks, exchanges (radials), deletions and translocations, resembling those described in Fanconi anemia. The insect had a normal phenotype, but its gametogenesis did not reach the spermatocyte II stage, and was quite poor in spermatocytes I. The clonal character of the chromosome instability was obvious owing to the incomplete cytodiaeresis of germ cells which remain associated by cytoplasmic bridges. This may be the first example of chromosome instability observed in animals from nature.
Genetic Characterization of a Sheep-Dwarf Goat Hybrid
Authors: Lühken G. , Wagner H.W. , Seichter D. , Hecht W. , Erhardt G.
Published: August 2009

Twelve weeks after repeated spontaneous mating between a Bentheimer Landschaf ram and a West African dwarf doe was observed, the doe aborted a dead fetus. The aim of this study was to verify the parentage and the species of the supposed parents and the hybrid status of the fetus, using cytogenetic and molecular genetic methods. For this purpose, karyotypes were prepared using fresh blood samples from the ram and the doe, and genomic DNA was extracted from blood of the suspected parents and tissue of the aborted fetus. Fragments of the nuclear DNA-encoded interleukin-2 gene and the mitochondrial DNA-encoded 16S ribosomal RNA were sequenced and 19 microsatellites were genotyped in all 3 animals. The karyotypes and DNA sequences of the ram and the doe corresponded to domestic sheep and goat, respectively. The interleukin-2 sequence of the fetus was heterozygous at all positions where sheep and goat have different nucleotides. None of the 19 microsatellites excluded the ram and the dwarf doe as parents of the fetus. Taken together, we can conclude that the ram and the dwarf doe were from the species Ovis aries and Capra hircus, respectively, and that they were most likely the parents of the aborted fetus, which itself proved to be a hybrid of these 2 species.
Etanercept Clearance during an in vitro Model of Continuous Venovenous Hemofiltration
Authors: Fleming Geoffrey M. , Salama Noha N. , Eid Saada K. , Cooke Kenneth R. , Mueller Bruce A.
Published: August 2009

Background/Aims: Etanercept is a tumor necrosis factor-α antagonist used in inflammation-mediated conditions. Continuous venovenous hemofiltration (CVVH) has also been used in patients with inflammatory conditions. This study evaluated etanercept clearance using an in vitro CVVH model. Methods: Etanercept clearance was assessed in vitro in bovine blood at 1–3 mg/l final serum concentration, and urea control at 750 mg/l. CVVH was performed using polyacrylonitrile, polysulfone, and polymethylmethacrylate filters at 3 l/h ultrafiltrate and 200 ml/min blood flow rates. Transmembrane clearance was estimated using sieving coefficient calculations, and adsorptive removal rate was approximated using a mass balance calculation. Results: Urea sieving coefficient remained constant (1.04 ± 0.01). Ultrafiltrate etanercept concentrations were undetectable (sieving coefficient < 0.02) and transmembrane and adsorptive clearances were negligible. Conclusion: Etanercept is not cleared appreciably by transmembrane or adsorptive mechanisms in CVVH using polyacrylonitrile, polysulfone, or polymethylmethacrylate hemofilters.
Role of Cytokines in the Pathophysiology of Acute-on-Chronic Liver Failure
Authors: Liu Qing
Published: August 2009

Background: This is the first ever decade which has witnessed the emergence of a highly lethal condition termed acute-on-chronic liver failure (ACLF), which today is the leading cause of death compared to acute and chronic liver failure. However, the complex pathophysiology of ACLF remains poorly understood. This article will attempt to summarize recent progress in the understanding of the mechanisms of cytokines in ACLF. Methods: The search terms used on PubMed were cytokines, liver injury, complications of liver disease, and hepatic progenitor cell. Results: Cytokines play a significant role in the pathophysiology of ACLF including hepatocellular death, extrahepatic complications and hepatocyte regeneration. The tissue-damaging mechanisms of cytokines are closely related to their hepatocyte proliferation and regeneration function. Conclusions: It remains a challenge to selectively prevent the detrimental effects of cytokines. To design interventions which selectively target the detrimental effects of cytokines, a detailed understanding of cytokines in the pathophysiology ACLF is critical.
Relationship of sRANKL Level and Vascular Calcification Score to Cardiovascular Events in Maintenance Hemodialysis Patients
Authors: Wei Tao , Wang Mei , Wang Mi , Gan Liang-Ying , Li Xin
Published: August 2009

Background: Vascular calcification and cardiovascular events are common in hemodialysis patients. Receptor activator of nuclear factor-κB ligand (RANKL) plays an important role in vascular calcification and bone remodeling. This study investigates the effects of soluble RANKL (sRANKL) on cardiovascular events in hemodialysis patients. Methods: Serum sRANKL levels of 47 patients were tested by ELISA. Vascular calcification was radiographically measured and patients were followed up for 2 years. Results: After 2 years, 10 (36.6%) patients had experienced cardiovascular events. Seventy-five percent (6/9) of mortality was due to cardiovascular disease. Patients experiencing cardiovascular events showed significantly higher vascular calcification scores (VCS) (3.20 ± 2.74 vs. 1.19 ± 1.60; t = 2.999; p < 0.05). Multivariate regression analysis showed that serum sRANKL levels, vascular calcification scores and phosphorus were independent determinants of cardiovascular events. Conclusion: Serum sRANKL levels and VCS are independent risk factors, and hemodialysis patients with low serum sRANKL levels have a risk of cardiovascular events.
Blind Verification of Elevated Platelet Autoantibodies in Serum of Schizophrenic Patients – Part II: Adult Subjects
Authors: Spivak Baruch , Schechtman Mila , Schönherz-Pine Yael , Blumensohn Rachel , Mostovoy Susanna , Amital Daniela , Deckmann Michael , Weizman Abraham , Shinitzky Meir
Published: August 2009

Background: In our preceding study, we assayed in a blind fashion the blood sera of young normal subjects and schizophrenic patients for levels of platelet autoantibodies (PAA). The recorded PAA titers of the schizophrenic patients were significantly higher than those of the normal subjects. This observation has lent support to this test being used as an objective evaluation of schizophrenia in young subjects in the future. In addition, this finding strongly suggested that the etiology of a distinct group of sufferers of this disorder could have originated from an autoimmune reaction against platelets which can, under certain conditions, cross-react with brain tissue. Aims: In the present study, PAA titers in the sera of adult schizophrenic patients and matched normal subjects were determined analogously to the preceding study. The effect of hospitalization and drug treatments on the apparent blood test scoring in adult subjects could thus be evaluated. Methods: A total of 46 schizophrenia patients (30 men and 16 women) aged 19–45 years (mean ± SD: 31.7 ± 8.0 years) with a minimum score of 60 on the Positive and Negative Symptom Scale and 43 healthy control subjects (22 men and 21 women) aged 21–44 years (mean ± SD: 31.9 ± 6.9 years) participated in the study. The blood titers of PAA were evaluated in a single-blind fashion using an optimized ELISA test scored by optical density (OD) units. A positive test was defined as a value above 1.3 OD units. Results: The titers of PAA in the group of schizophrenic patients (1.1 ± 0.55 OD units, range: 0.360–2.285 OD units) were significantly higher in comparison to those of the healthy control subjects (0.81 ± 0.37 OD units, range: 0.360–1.704 OD units; p = 0.004, two-tailed unpaired t-test). Significantly more schizophrenic patients showed a positive test (15 patients out of 46) than the control subjects (5 out of 43). However, significantly higher OD values of 1.55 ± 0.5 were recorded in the group of patients with less than 3 years of registered disease (n = 16, age 19–30 years), while in the group with 4–20 years of hospitalization (n = 30, age 24–45 years) the recorded OD values (0.85 ± 0.4 OD units) were practically indistinguishable from those of the control group. Conclusions: In the adult schizophrenic patients, the PAA blood test remains valid for patients who were hospitalized for less than 3 years. Drug treatment, length of disease and age can be assumed to reduce the PAA level considerably.
Mechanism of Visual Sensations Experienced during Pars Plana Vitrectomy under Retrobulbar Anesthesia
Authors: Sugisaka Eiko , Shinoda Kei , Sano Ronaldo Yuiti , Ishida Susumu , Imamura Yutaka , Ozawa Yoko , Shinoda Hajime , Suzuki Kotaro , Tsubota Kazuo , Inoue Makoto
Published: August 2009

Purpose: To investigate the visual sensations experienced by patients during vitrectomy under retrobulbar anesthesia. Methods: 30 men and 45 women with a mean age of 65.3 ± 10.6 years underwent vitrectomy under retrobulbar anesthesia for macular disease. 28 eyes had an idiopathic epiretinal membrane, 13 had an idiopathic macular hole, 32 had macular edema (17 diabetic retinopathy and 15 retinal vein occlusion), and 2 had submacular hemorrhage. 49 patients with nonmacular disease underwent similar vitrectomy procedures and were used for comparison. An interview was conducted with the patient about his/her visual sensations during and within 3 h of the vitrectomy. Results: 70 (93.3%) of the patients reported seeing lights, 53 (70.7%) reported seeing colors, and 48 (64.0%) reported seeing movements or moving objects. Of the patients who reported seeing movements or moving objects, 44 (58.7%) reported seeing surgical instruments, and 5 (6.7%) saw the surgeon’s fingers or hands. Patients with macular diseases tended to report more visual sensations than patients with nonmacular diseases. The patients’ description and drawings appeared to arise mainly from the shadows cast by the intravitreal objects, and some patients perceived highly accurate details including the movements and color of the objects. Conclusions: Visual sensations are experienced by approximately 90% of the patients, and there may be a common mechanism by which patients perceive the intravitreal objects that are not focused on by the retina through the eye’s optical system.
The Word Processing Deficit in Semantic Dementia: All Categories Are Equal, but Some Categories Are More Equal than Others
Authors: Pulvermüller Friedemann , Cooper-Pye Elisa , Dine Clare , Hauk Olaf , Nestor Peter J. , Patterson Karalyn
Published: September 2009

It has been claimed that semantic dementia (SD), the temporal variant of fronto-temporal dementia, is characterized by an across-the-board deficit affecting all types of conceptual knowledge. We here confirm this generalized deficit but also report differential degrees of impairment in processing specific semantic word categories in a case series of SD patients (N = 11). Within the domain of words with strong visually grounded meaning, the patients' lexical decision accuracy was more impaired for color-related than for form-related words. Likewise, within the domain of action verbs, the patients' performance was worse for words referring to face movements and speech acts than for words semantically linked to actions performed with the hand and arm. Psycholinguistic properties were matched between the stimulus groups entering these contrasts; an explanation for the differential degrees of impairment must therefore involve semantic features of the words in the different conditions. Furthermore, this specific pattern of deficits cannot be captured by classic category distinctions such as nouns versus verbs or living versus nonliving things. Evidence from previous neuroimaging research indicates that color- and face/speech-related words, respectively, draw most heavily on anterior-temporal and inferior-frontal areas, the structures most affected in SD. Our account combines (a) the notion of an anterior-temporal amodal semantic “hub” to explain the profound across-the-board deficit in SD word processing, with (b) a semantic topography model of category-specific circuits whose cortical distributions reflect semantic features of the words and concepts represented.
An Extremum Solution of the Monin–Obukhov Similarity Equations
Authors: Wang Jingfeng , Bras Rafael L.
Published: August 2009

An extremum hypothesis of turbulent transport in the atmospheric surface layer is postulated. The hypothesis has led to a unique solution of Monin–Obukhov similarity equations in terms of simple expressions linking shear stress (momentum flux) and heat flux to mean wind shear and temperature gradient. The extremum solution is consistent with the well-known asymptotic properties of the surface layer. Validation of the extremum solution has been made by comparison to field measurements of momentum and heat fluxes. Furthermore, a modeling test of predicting surface heat fluxes using the results of this work is presented. A critical reexamination of the interpretation of the Obukhov length is given.
Mixed Layer Temperature Response to the Southern Annular Mode: Mechanisms and Model Representation
Authors: Screen James A. , Gillett Nathan P. , Karpechko Alexey Yu , Stevens David P.
Published: August 2009

Previous studies have shown that simulated sea surface temperature (SST) responses to the southern annular mode (SAM) in phase 3 of the Coupled Model Intercomparison Project (CMIP3) climate models compare poorly to the observed response. The reasons behind these model inaccuracies are explored. The ocean mixed layer heat budget is examined in four of the CMIP3 models and by using observations–reanalyses. The SST response to the SAM is predominantly driven by sensible and latent heat flux and Ekman heat transport anomalies. The radiative heat fluxes play a lesser but nonnegligible role. Errors in the simulated SST responses are traced back to deficiencies in the atmospheric response to the SAM. The models exaggerate the surface wind response to the SAM leading to large unrealistic Ekman transport anomalies. During the positive phase of the SAM, this results in excessive simulated cooling in the 40°–65°S latitudes. Problems with the simulated wind stress responses, which relate partly to errors in the simulated winds themselves and partly to the transfer coefficients used in the models, are a key cause of the errors in the SST response. In the central Pacific sector (90°–150°W), errors arise because the simulated SAM is too zonally symmetric. Substantial errors in the net shortwave radiation are also found, resulting from a poor representation of the changes in cloud cover associated with the SAM. The problems in the simulated SST responses shown by this study are comparable to deficiencies previously identified in the CMIP3 multimodel mean. Therefore, it is likely that the deficiencies identified here are common to other climate models.
Mechanisms of Climate Change in the Semiarid African Sahel: The Local View
Authors: Giannini Alessandra
Published: September 2009

Application of the moist static energy framework to analyses of vertical stability and net energy in the Sahel sheds light on the divergence of projections of climate change. Two distinct mechanisms are sketched. In one, anthropogenic warming changes continental climate indirectly: warming of the oceans increases moist static energy at upper levels, affecting vertical stability globally, from the top down, and driving drying over the Sahel, in a way analogous to the impact of El Niño–Southern Oscillation on the global tropical atmosphere. In the other, the increase in anthropogenic greenhouse gases drives a direct continental change: the increase in net terrestrial radiation at the surface increases evaporation, favoring vertical instability and near-surface convergence from the bottom up.

In both cases the surface warms, but in the first precipitation and evaporation decrease, while in the second they increase. In the first case, land surface warming is brought about by the remotely forced decrease in precipitation and consequent decrease in evaporation and increase in net solar radiation at the surface. In the second, it is brought about by the increase in net terrestrial radiation at the surface, amplified by the water vapor feedback associated with an increase in near-surface humidity.
Simulating the Effects of Irrigation over the United States in a Land Surface Model Based on Satellite-Derived Agricultural Data
Authors: Ozdogan Mutlu , Rodell Matthew , Beaudoing Hiroko Kato , Toll David L.
Published: August 2009

A novel method is introduced for integrating satellite-derived irrigation data and high-resolution crop-type information into a land surface model (LSM). The objective is to improve the simulation of land surface states and fluxes through better representation of agricultural land use. Ultimately, this scheme could enable numerical weather prediction (NWP) models to capture land–atmosphere feedbacks in managed lands more accurately and thus improve forecast skill. Here, it is shown that the application of the new irrigation scheme over the continental United States significantly influences the surface water and energy balances by modulating the partitioning of water between the surface and the atmosphere. In this experiment, irrigation caused a 12% increase in evapotranspiration (QLE) and an equivalent reduction in the sensible heat flux (QH) averaged over all irrigated areas in the continental United States during the 2003 growing season. Local effects were more extreme: irrigation shifted more than 100 W m−2 from QH to QLE in many locations in California, eastern Idaho, southern Washington, and southern Colorado during peak crop growth. In these cases, the changes in ground heat flux (QG), net radiation (RNET), evapotranspiration (ET), runoff (R), and soil moisture (SM) were more than 3 W m−2, 20 W m−2, 5 mm day−1, 0.3 mm day−1, and 100 mm, respectively. These results are highly relevant to continental-to-global-scale water and energy cycle studies that, to date, have struggled to quantify the effects of agricultural management practices such as irrigation. On the basis of the results presented here, it is expected that better representation of managed lands will lead to improved weather and climate forecasting skill when the new irrigation scheme is incorporated into NWP models such as NOAA’s Global Forecast System (GFS).
Regularized Logistic Models for Probabilistic Forecasting and Diagnostics
Authors: Bröcker Jochen
Published: August 2009

Logistic models are studied as a tool to convert dynamical forecast information (deterministic and ensemble) into probability forecasts. A logistic model is obtained by setting the logarithmic odds ratio equal to a linear combination of the inputs. As with any statistical model, logistic models will suffer from overfitting if the number of inputs is comparable to the number of forecast instances. Computational approaches to avoid overfitting by regularization are discussed, and efficient techniques for model assessment and selection are presented. A logit version of the lasso (originally a linear regression technique), is discussed. In lasso models, less important inputs are identified and the corresponding coefficient is set to zero, providing an efficient and automatic model reduction procedure. For the same reason, lasso models are particularly appealing for diagnostic purposes.
The Antiarrhythmic Effect and Possible Ionic Mechanisms of Pilocarpine on Animal Models
Authors: Zhao Wei-ming , Qi Han-ping , Liu Ying , Chen Wei , Xie Jing , Pan Zhen-yu , Han Hong-mei , Chen Li-peng , Li Dan-lu , Wang Li-yan , Sun Hong-li , Liu Yan
Published: August 2009

This study was designed to evaluate the effects of pilocarpine and explore the underlying ionic mechanism, using both aconitine-induced rat and ouabain-induced guinea pig arrhythmia models. Confocal microscopy was used to measure intracellular free-calcium concentrations ([Ca2+]i) in isolated myocytes. The current data showed that pilocarpine significantly delayed onset of arrhythmias, decreased the time course of ventricular tachycardia and fibrillation, reduced arrhythmia score, and increased the survival time of arrhythmic rats and guinea pigs. [Ca2+]ioverload induced by aconitine or ouabain was reduced in isolated myocytes pretreated with pilocarpine. Moreover, M3-muscarinic acetylcholine receptor (mAChR) antagonist 4-DAMP (4-diphenylacetoxy-N-methylpiperidine-methiodide) partially abolished the beneficial effects of pilocarpine. These data suggest that pilocarpine produced antiarrhythmic actions on arrhythmic rat and guinea pig models induced by aconitine or ouabain via stimulating the cardiac M3-mAChR. The mechanism may be related to the improvement of Ca2+handling.
Partial Hindlimb Occlusion Reduced the Susceptibility to Sustained Ventricular Tachycardia in Conscious Rats
Authors: Lujan Heidi L. , DiCarlo Stephen E.
Published: August 2009

Remote conditioning induced by ischemia in distant organs protects the heart from ischemia/reperfusion injury; however, its effect on ischemia-induced ventricular arrhythmias is unknown. Therefore, we tested the hypothesis that partial hindlimb occlusion during coronary artery occlusion increases the ventricular arrhythmia threshold (VAT) induced by coronary artery occlusion. Rats (n = 7) were instrumented with a radio-telemetry device for recording arterial pressure, electrocardiogram (ECG), and body temperature. A Doppler ultrasonic flow probe and vascular occluder were placed around the terminal aorta. Finally, a snare was placed around the left main coronary artery. The VAT was determined without and, on an alternate day, during partial hindlimb occlusion (remote conditioning) in conscious rats. Without remote conditioning, the VAT was 4.56 + 0.15 minutes. Importantly, remote conditioning significantly increased the VAT (6.29 + 0.49 minutes), suggesting that ischemia in a distant organ may delay the development of ischemia-induced ventricular arrhythmias.
GAP-134 ([2S,4R]-1-[2-Aminoacetyl]4-Benzamidopyrrolidine-2-Carboxylic Acid) Prevents Spontaneous Ventricular Arrhythmias and Reduces Infarct Size During Myocardial Ischemia/Reperfusion Injury in Open-Chest Dogs
Authors: Hennan James K. , Swillo Robert E. , Morgan Gwen A. , Rossman Eric I. , Kantrowitz Joel , Butera John , Petersen Jorgen S. , Gardell Stephen J. , Vlasuk George P.
Published: August 2009

The antiarrhythmic dipeptide, GAP-134, ([2S,4R]-1[2-aminoacetyl]-4-benzamido-pyrrolidine-2-carboxylic acid) was evaluated in canine ischemia/reperfusion model. In dogs subjected to 60-minute ischemia and 4-hour reperfusion, GAP-134 was administered 10 minutes before reperfusion as a bolus + intravenous (IV) infusion. The doses administered were 0.25 µg/kg bolus + 0.19 µg/kg per hour infusion; 2.5 µg/kg + 1.9 µg/kg per hour; 25 mg/kg + 19 mg/kg per hour; 75 mg/kg + 57 mg/kg per hour. Ventricular ectopy was quantified during reperfusion, including premature ventricular contractions (PVC) and ventricular tachycardia (VT). Total incidence of VT was reduced significantly with the 2 highest doses of GAP-134 (1.7 + 0.8; 2.2 + 1.4 events; P < .05) compared to controls (23.0 + 6.1). Total PVCs were reduced significantly from 11.1 + 1.6% in control animals to 2.0% + 0.7% and 1.8% + 0.8% after the 2 highest doses of GAP-134. Infarct size, expressed as percentage of left ventricle, was reduced significantly from 19.0% + 3.5% in controls to 7.9% + 1.5% and 7.1% + 0.8% (P < .05) at the 2 highest doses of GAP-134. GAP-134 is an effective antiarrhythmic agent with potential to reduce ischemia/reperfusion injury.
Longitudinal Effects of Impact Fees and Special Assessments on the Level of Capital Spending, Taxes, and Long-Term Debt in American Cities
Authors: Jung Changhoon , Roh Chul-Young , Kang Younguck
Published: August 2009

This article examines whether the use of impact fees and special assessments affect the level of capital spending and two major own source revenues of local capital spending (taxes and long-term debt) by analyzing a panel of 695 American cities with populations over 20,000 during the time period of 1980—2000. Since impact fees and special assessments are heavily used in a growing community and because it covers less than half the costs of new development, the findings demonstrate that the private financing of public infrastructure (impact fees and special assessments) increases the level of local capital spending. It also leads to an increase in the level of long-term debt use. Although it provides partial tax relief, it is not a strong substitute for taxes. Thus, impact fees and special assessments are not a substitute for local capital spending. It is rather a supplemental revenue source to fund local capital infrastructure.
Obstacles and Proposed Solutions to Effective Antiretroviral Therapy in Resource-Limited Settings
Authors: Bartlett John A. , Hornberger John , Shewade Ashwini , Bhor Menaka , Rajagopalan Rukmini
Published: August 2009

More than 3 million people were receiving antiretroviral therapy (ART) at the end of 2007, but this number represents only 31% of people clinically eligible for ART in resource-limited settings. The primary objective of this study is to summarize the key obstacles that impede the goal of universal access prevention, care, and treatment. We performed a systematic literature search to review studies that reported barriers to diagnosis and access to treatment of HIV/AIDS in resource-limited countries. Persons living with HIV/ AIDS commonly face economic, sociocultural, and behavioral obstacles to access treatment and care for HIV. A variety of programs to overcome these barriers have been implemented, including efforts to destigmatize HIV/AIDS, enhance treatment literacy, provide income-generation skills, decentralize HIV services, promote gender equality, and adopt a multisectoral approach to optimize limited resources. An understanding of these obstacles and suggested methods to overcome them must be addressed by global policy makers before universal ART access can be achieved.
Processes, microstructure and properties of vanadium microalloyed steels
Authors: Baker T. N.
Published: August 2009

Vanadium as an important alloying element in steels was initially associated with the properties achieved following tempering. Interest in the microstructure was stimulated by the advent of transmission electron microscopes with a resolution of ∼1 nm together with selected area electron diffraction techniques. A second timely development was that of controlled rolling, particularly of plate and sheet products. The scope of this review will include the historical background on quenched and tempered vanadium steels, precipitation during isothermal aging, conventional controlled rolling and during thin slab direct charging and the development of strength and toughness in vanadium microalloyed steels. The characterisation of microstructure, in particular the methods for the analysis of the chemical composition of precipitates has progressed since the availability of X-ray energy dispersive analysis in the 1970s, and the role played by electron energy loss spectroscopy in providing quantitative analysis of carbon and nitrogen in vanadium microalloyed steels will be presented. There are still many topics involving vanadium microalloyed steels that are controversial. These include the nucleation sequence of homogeneous precipitates of vanadium carbonitride and whether this occurs coherently, the composition of the vanadium precipitates, the nucleation mechanism for interphase precipitation, the importance of strain induced precipitation in austenite of vanadium carbonitride, the contributions of both interphase precipitation and random precipitation in ferrite to the yield strength, and the role of the process route parameters in developing properties. These topics will be considered in this paper which concentrates on hot rolled vanadium microalloyed steels placed in the context of pertinent research on other alloys.
Effects of composition and processing parameters on precipitation and texture formation in microalloyed interstitial free high strength (IFHS) steels
Authors: Ray R. K. , Ghosh P. , Bhattacharjee D.
Published: August 2009

Precipitation in IFHS steels affects texture formation during annealing, which in turn determines the formability. The single most important type of precipitates in IFHS steels is FeTiP. Precipitation of FeTiP leads to the decrement in the intensity of the favourable {111} texture, which causes a degradation of the formability properties. The batch annealed steels are particularly susceptible to this. Since formation of FeTiP as well as of the other types of precipitates in IFHS steels is dependent on steel composition and processing parameters, a detailed and systematic investigation is urgently needed to look into the various aspects of precipitation in IFHS steels. Proper scientific investigation is expected to provide necessary processing windows that will not allow formation of unwanted precipitates. This will help in maximising the strengthening effects of P, without any degradation of the deep drawability of the steels.
Microalloy steels – the beginning
Authors: Morrison W. B.
Published: August 2009

Although steels containing small amounts of vanadium or titanium had long been available, the rapid development and exploitation of microalloy steels was initiated by the recognition of the advantages of adding a small amount of niobium to C–Mn steels. This occurred in 1958 with the first successful production of niobium treated steel by the Great Lakes Steel Corporation of the USA. Various factors contributed towards this development including the availability of a supply of relatively low cost ferroniobium in the late 1950s and the discovery at this time of very large deposits of niobium bearing ores in Brazil and Canada which guaranteed the stability of future supply and price. Further development of microalloy steels was held back by a lack of knowledge of the exact role of niobium in influencing steel properties. Research carried out at The University of Sheffield in 1959–1960 provided a fundamental understanding of the effect of niobium. This was the first of many scientific investigations to study the influence of niobium, vanadium and titanium which contributed to the successful development and production of microalloy steels.
Fracture strength and toughness of ultra high strength TRIP aided steels
Authors: Sugimoto K.-I.
Published: August 2009

The performance of hydrogen embrittlement, fatigue properties and impact toughness of ultra high strength transformation induced plasticity aided steels with bainitic ferrite matrix (TBF steels) has been discussed. Some characteristics and deformation transformation mechanism of the retained austenite has also been discussed. It has been observed that mechanical stability and volume fraction of the interlath retained austenite phase in the TBF steels play an important role in increasing delayed fracture strength, fatigue limit and impact toughness.
New approach for modelling strain induced precipitation of Nb(C,N) in HSLA steels during multipass hot deformation in austenite
Authors: Nagarajan V. , Palmiere E. J. , Sellars C. M.
Published: August 2009

A new model for strain induced precipitation of Nb(C,N) is developed from the existing model for single pass hot deformation. This new model can be extended to multipass deformation to explain the microstructural evolution during the hot deformation of Nb supersaturated high strength low alloy (HSLA) steels. The key feature of this model is the microband geometry employed, which leads to determination of the local solute concentration at microbands, and hence the potential for carbonitride precipitation on the microbands. The model also validates the need for concurrent growth and coarsening processes, even at the early stages of precipitation. The evolution of the precipitate radius, number density and volume fraction are compared with the experimental results obtained from thin foil TEM micrographs on Fe–30 wt-%Ni alloys (that are austenitic at room temperature and are similar to HSLA steels in deformation behaviour) subjected to deformation by plane strain compression. The model predictions are in good agreement with experimental results.
Development and first validation of the COPD Assessment Test
Authors: Jones P. W. , Harding G. , Berry P. , Wiklund I. , Chen W-H. , Kline Leidy N.
Published: August 2009

There is need for a validated short, simple instrument to quantify chronic obstructive pulmonary disease (COPD) impact in routine practice to aid health status assessment and communication between patient and physician. Current health-related quality of life questionnaires provide valid assessment of COPD, but are complex, which limits routine use.

The aim of the present study was to develop a short validated patient-completed questionnaire, the COPD Assessment Test (CAT), assessing the impact of COPD on health status.

21 candidate items identified through qualitative research with COPD patients were used in three prospective international studies (Europe and the USA, n = 1,503). Psychometric and Rasch analyses identified eight items fitting a unidimensional model to form the CAT. Items were tested for differential functioning between countries. Internal consistency was excellent: Cronbach's α = 0.88. Test re-test in stable patients (n = 53) was very good (intra-class correlation coefficient 0.8). In the sample from the USA, the correlation with the COPD-specific version of the St George’s Respiratory Questionnaire was r = 0.80. The difference between stable (n = 229) and exacerbation patients (n = 67) was five units of the 40-point scale (12%; p<0.0001).

The CAT is a short, simple questionnaire for assessing and monitoring COPD. It has good measurement properties, is sensitive to differences in state and should provide a valid, reliable and standardised measure of COPD health status with worldwide relevance.