bluuebunny/crossref_metadata_2025 huggingface dataset:
Cryoprotective mechanism of a small intrinsically disordered dehydrin protein
Authors: Hughes Stephanie , Graether Steffen P.
Published: October 2010

Dehydration proteins (Dehydrins) are expressed during dehydration stress in plants and are thought to protect plant proteins and membranes from the loss of water during drought and at cold temperatures. Several different dehydrins have been shown to protect lactate dehydrogenase (LDH) from damage from being frozen and thawed. We show here that a 48 residue K2 dehydrin from Vitis riparia protects LDH more effectively than bovine serum albumin, a protein with known cryoprotective function. Light scattering and 8‐anilino‐1‐naphthalene sulfonate fluorescence experiments show that dehydrins prevent aggregation and unfolding of the enzyme. The cryoprotective effects of LDH are reduced by the addition of salt, suggesting that the positively charged K‐segments are attracted to a negatively charged surface but this does not result in binding. Overall K2 is an intrinsically disordered protein; nuclear magnetic resonance relaxation experiments indicate that the two‐terminal, Lys‐rich K‐segments show a weak propensity for α‐helicity and are flexible, and that the central, polar rich phi‐segment has no secondary structure preference and is highly flexible. We propose that the phi‐segments in dehydrins are important for maintaining the disordered structure so that the protein can act as a molecular shield to prevent partially denatured proteins from interacting with one another, whereas the K‐segments may help to localize the dehydrin near the enzyme surface.
The C. elegans B‐cell lymphoma 2 (Bcl‐2) homolog cell death abnormal 9 (CED‐9) associates with and remodels LIPID membranes
Authors: Tan Frederick J. , Zuckerman Jonathan E. , Wells Robert C. , Hill R. Blake
Published: October 2010

Bcl‐2 proteins associate with and remodel mitochondria to regulate apoptosis. While the C. elegans Bcl‐2 homolog CED‐9 constitutively associates with mitochondria, it is unclear whether or not this association reflects an innate ability of CED‐9 to directly remodel mitochondrial membranes. To address this question, we have characterized the effects of recombinantly expressed and purified CED‐9 on synthetic lipid vesicles. We found that CED‐9 associates with anionic lipid vesicles at neutral pH, and that association can occur independently of the C‐terminal transmembrane domain. Membrane association changes the environment of CED‐9 tryptophans and results in an apparent increase in α‐helical structure. Upon association, CED‐9 alters the permeability of membranes resulting in leakage of encapsulated dyes. Furthermore, this membrane remodeling promotes membrane fusion upon protonation of CED‐9. Bypass of this protonation trigger can be achieved by mutating two conserved glutamates (E187K/E190K) or removing the N‐terminal 67 residues. Together, these in vitro results suggest that CED‐9 retains the amphitropic ability of mammalian Bcl‐2 proteins to associate with cellular membranes. We therefore discuss the possibility that CED‐9 and other Bcl‐2 homologs localize at mitochondria to regulate mitochondrial homeostasis by either modulating mitochondrial membrane permeability or fusion.
The crystal structures of the Salmonella type III secretion system tip protein SipD in complex with deoxycholate and chenodeoxycholate
Authors: Chatterjee Srirupa , Zhong Dalian , Nordhues Bryce A. , Battaile Kevin P. , Lovell Scott , De Guzman Roberto N.
Published: October 2010

The type III secretion system (T3SS) is a protein injection nanomachinery required for virulence by many human pathogenic bacteria including Salmonella and Shigella. An essential component of the T3SS is the tip protein and the Salmonella SipD and the Shigella IpaD tip proteins interact with bile salts, which serve as environmental sensors for these enteric pathogens. SipD and IpaD have long central coiled coils and their N‐terminal regions form α‐helical hairpins and a short helix α3 that pack against the coiled coil. Using AutoDock, others have predicted that the bile salt deoxycholate binds IpaD in a cleft formed by the α‐helical hairpin and its long central coiled coil. NMR chemical shift mapping, however, indicated that the SipD residues most affected by bile salts are located in a disordered region near helix α3. Thus, how bile salts interact with SipD and IpaD is unclear. Here, we report the crystal structures of SipD in complex with the bile salts deoxycholate and chenodeoxycholate. Bile salts bind SipD in a region different from what was predicted for IpaD. In SipD, bile salts bind part of helix α3 and the C‐terminus of the long central coiled coil, towards the C‐terminus of the protein. We discuss the biological implication of the differences in how bile salts interact with SipD and IpaD.
Lectures on generalized complex geometry for physicists
Authors: Koerber P.
Published: October 2010

In these lectures we review Generalized Complex Geometry and discuss two main applications to string theory: the description of supersymmetric flux compactifications and the supersymmetric embedding of D‐branes. We start by reviewing G‐structures, and in particular SU(3)‐structure and its torsion classes, before extending to Generalized Complex Geometry. We then discuss the supersymmetry conditions of type II supergravity in terms of differential conditions on pure spinors, and finally introduce generalized calibrations to describe D‐branes. As examples we discuss in some detail AdS4compactifications, which play a role as the geometric duals in the AdS4/CFT3‐correspondence.
Elevated expression of cancer‐associated proliferating cell nuclear antigen in high‐grade prostatic intraepithelial neoplasia and prostate cancer
Authors: Wang Xiaoyan , Hickey Robert J. , Malkas Linda H. , Koch Michael O. , Li Lang , Zhang Shaobo , Sandusky George E. , Grignon David J. , Eble John N. , Cheng Liang
Published: October 2010

BACKGROUND

Proliferating cell nuclear antigen (PCNA) plays an important role in DNA replication and repair. The expression and potential utility of this marker in prostatic neoplasia is uncertain. With the development of this new caPCNA selective antibody, we explored the potential utility of this marker in prostate cancer.

METHODS

Using a traditional primary Fab2' rabbit anti‐caPCNA antibody‐HRP conjugated secondary anti‐Fab2' antibody format, the expression of the caPCNA was analyzed in prostate tissue from 89 radical prostatectomy specimens. The caPCNA expression was correlated with clinicopathologic characteristics.

RESULTS

The fraction of cells staining positively with caPCNA antibody in prostatic adenocarcinoma (mean, 23%) was significantly higher than that in benign prostatic epithelium (mean, 2%; P < 0.001) or high‐grade prostatic intraepithelial neoplasia (PIN) (mean, 6%; P < 0.05). Moreover, the intensity of caPCNA expression in prostatic adenocarcinoma (mean, 2.9) was significantly higher than that in benign prostatic tissue (mean, 0.7; P < 0.001) or high‐grade PIN (mean, 2.0; P < 0.001). Benign prostatic epithelium showed only minimal or negative reactivity. There was significant correlation between the percentage of caPCNA expression and primary Gleason grade (P = 0.01), and with Gleason score (P = 0.02). Adenocarcinomas with positive vascular invasion had a significantly higher percentage of cells staining with caPCNA antibody (P < 0.0001) and a higher intensity of caPCNA expression (P = 0.04).

CONCLUSIONS

Our data indicate that increased expression of the cancer‐associated isoform of PCNA is common in prostatic adenocarcinoma and its precursor and may be a useful biomarker. Prostate 71:748–754, 2011. © 2010 Wiley‐Liss, Inc.
Topographical analysis of telomere length and correlation with genomic instability in whole mount prostatectomies
Authors: Joshua A.M. , Shen E. , Yoshimoto M. , Marrano P. , Zielenska M. , Evans A.J. , Van der Kwast T. , Squire J.A.
Published: October 2010

BACKGROUND

Many critical events in prostatic carcinogenesis appear to relate to the emergence of genomic instability. Characteristic genomic abnormalities such as 8p loss, 8q gain, trisomy 7, and PTEN microdeletions may provide selective advantages to increase neoplastic transformation. Evidence suggests that telomere dysfunction is a plausible mechanism for some of these abnormalities on the basis of the break‐fusion‐bridge cycle that can lead to manifestations of genomic instability.

METHODS

In this study, we correlate telomere length measured by quantitative FISH in various prostatic histologies with markers of genomic instability and immunohistochemical measures of proliferation and oxidative stress.

RESULTS

We find that telomere shortening is correlated with abnormalities on chromosome 8, but not with trisomy 7 or abnormalities of the PTEN locus. There are associations with C‐MYC aberrations in stroma with greater proximity to cancer and a correlation between telomere length in a number of prostatic histologies and the adjacent stroma, suggesting the importance of microenvironmental effects on telomere maintenance in the prostate. This finding was also supported by the finding of the correlation between telomere attrition and the levels of oxidative stress as measured by malondialdehyde staining in HPIN lesions close to cancer.

CONCLUSIONS

Telomere attrition in the prostate gland is associated with particular genomic aberrations that contribute to the genomic instability characteristic of prostatic carcinogenesis. Correlations between various histologies and adjacent stroma telomere length suggest it is also may reveal microenvironmental effects within the prostate gland. Oxidative stress may contribute to telomere attrition in HPIN close to cancer. Prostate 71:778–790, 2011. © 2010 Wiley‐Liss, Inc.
Suppression of glycogen synthase kinase 3 activity reduces tumor growth of prostate cancer in vivo
Authors: Zhu Qing , Yang Jun , Han Suxia , Liu Jihong , Holzbeierlein Jeffery , Thrasher J. Brantley , Li Benyi
Published: October 2010

BACKGROUND

Glycogen synthase kinase 3 (GSK‐3) has been regarded as a potential therapeutic target for multiple human cancers. We previously reported that suppression of GSK‐3 activity with lithium chloride (LiCl) or small chemical inhibitors impaired cellular DNA synthesis and reduced cell proliferation in prostate cancer cells. Therefore, in this study, we extended this in vitro findings to in vivo settings in order to establish a proof of concept that inhibition of GSK‐3 activity is feasible in suppressing tumor growth of prostate cancer in vivo.

METHODS

In this study, we used three GSK‐3 inhibitors, LiCl, TDZD‐8, and L803‐mts, which are structurally unrelated and non‐ATP competitive. Human prostate cancer cell lines PC‐3 and C4‐2 were used for nude mouse xenograft models. The autochthonous transgenic prostate cancer TRAMP mice were used for testing GSK‐3 inhibitor's effect on tumor development. Anti‐Ki‐67 and BrdU immunohistochemistry was used to determine cell proliferation. The pE2F‐TA‐LUC (E2F‐LUC) luciferase reporter assay and gene specific small interferencing RNA technique were used to examine C/EBP involvement in GSK‐3 inhibitor‐induced E2F‐1 suppression.

RESULTS

Using mouse xenograft models, we demonstrated that LiCl and TDZD‐8 significantly suppressed tumor development and growth of subcutaneous xenografts derived from human prostate cancer cells. Similarly, in the TRAMP mice, TDZD‐8 and L803‐mts reduced the incidence and tumor burden in the prostate lobes. Consistent with our previous in vitro findings, GSK‐3 inhibitors significantly reduced BrdU incorporation and Ki67‐positive cells in xenograft tumors and mouse cancerous prostates compared to the control. Further analysis revealed that following GSK‐3 inhibition, C/EBPα, a negative cell cycle regulator, was remarkably accumulated in xenograft tumors or in cultured prostate cancer cells. Meanwhile, knocking down C/EBPα expression abolished GSK‐3 inhibition‐induced suppression of E2F1 transactivation, suggesting that C/EBPα accumulation is involved in GSK‐3 inhibition‐induced anti‐tumor effect.

CONCLUSION

Taken together, these results suggest that GSK‐3 inhibition has the potential as a therapeutic strategy for prostate cancer intervention, although further pre‐clinical and clinical testing are desirable. Prostate 71:835–845, 2011. © 2010 Wiley‐Liss, Inc.
Protein domain assignment from the recurrence of locally similar structures
Authors: Tai Chin‐Hsien , Sam Vichetra , Gibrat Jean‐Francois , Garnier Jean , Munson Peter J. , Lee Byungkook
Published: October 2010

Domains are basic units of protein structure and essential for exploring protein fold space and structure evolution. With the structural genomics initiative, the number of protein structures in the Protein Databank (PDB) is increasing dramatically and domain assignments need to be done automatically. Most existing structural domain assignment programs define domains using the compactness of the domains and/or the number and strength of intra‐domain versus inter‐domain contacts. Here we present a different approach based on the recurrence of locally similar structural pieces (LSSPs) found by one‐against‐all structure comparisons with a dataset of 6373 protein chains from the PDB. Residues of the query protein are clustered using LSSPs via three different procedures to define domains. This approach gives results that are comparable to several existing programs that use geometrical and other structural information explicitly. Remarkably, most of the proteins that contribute the LSSPs defining a domain do not themselves contain the domain of interest. This study shows that domains can be defined by a collection of relatively small locally similar structural pieces containing, on average, four secondary structure elements. In addition, it indicates that domains are indeed made of recurrent small structural pieces that are used to build protein structures of many different folds as suggested by recent studies. Proteins 2011. Published 2010 Wiley‐Liss, Inc.
The effects of the L29F mutation on the ligand migration kinetics in crystallized myoglobin as revealed by molecular dynamics simulations
Authors: Anselmi Massimiliano , Di Nola Alfredo , Amadei Andrea
Published: October 2010

By using multiple molecular dynamics (MD) trajectories, a quantitative description of carbon monoxide (CO) migration within crystal of L29F myoglobin mutant (L29F‐Mb) was obtained. The aim was to provide a detailed model for ligand diffusion in the protein to be compared to the available L29F‐Mb experimental‐computational data and to the corresponding model kinetics we previously obtained for photolyzed CO within crystallized wild‐type myoglobin (wt‐Mb). Results suggest a clear migration pathway from distal pocket to the proximal site, similar to the one observed in wt‐Mb, with a relaxation kinetics differing from the wt‐Mb one essentially for the escape rate which is much higher in the mutant. Moreover MD data indicated a clear correlation between CO location within the protein and the conformation adopted by Phe29, well matching the available experimental data as obtained by time‐resolved X‐ray density maps. Such data, further validating the model used in the simulations, point out the subtle mutual effect between ligand diffusion and protein functional motions possibly explaining the observed dramatic variation of CO exit rate in L29F‐Mb. Proteins 2011. © 2010 Wiley‐Liss, Inc.
Induction effects of host plants on insecticide susceptibility and detoxification enzymes of Bemisia tabaci (Hemiptera: Aleyrodidae)
Authors: Xie Wen , Wang Shaoli , Wu Qingjun , Feng Yuntao , Pan Huipeng , Jiao Xiaoguo , Zhou Long , Yang Xin , Fu Wei , Teng Haiyuan , Xu Baoyun , Zhang Youjun
Published: October 2010

BACKGROUND: The polyphagous B‐biotype Bemisia tabaci (Gennadius) has developed a high resistance to commonly used insecticides in China. To illustrate the induced changes by host plant, bioassay and biochemical research on five different host populations were investigated.

RESULTS: Except for bifenthrin, all tested insecticides showed lower toxicity to the B. tabaci poinsettia population compared with other host populations. Moreover, four insecticides, the exceptions being abamectin and fipronil, showed highest toxicity towards the tomato population. The LC50 values of the poinsettia population, particularly towards acetamiprid, were 14.8‐, 10.3‐ and 7.29‐fold higher than those of tomato, cucumber and cabbage respectively. The CarE activities of B. tabaci cabbage and cucumber populations were all significantly higher than those of poinsettia, cotton and tomato populations. The ratio of the cabbage population was 1.97‐, 1.79‐ and 1.30‐fold higher than that of poinsettia, cotton and tomato respectively. The frequency profiles for this activity also have obvious differences. The GST and P450 activities of the cucumber population were the lowest in the five host populations.

CONCLUSION: Long‐term induction of host plants for B‐biotype B. tabaci could influence their susceptibilities to several insecticides. Rational selection and usage of insecticides for particular hosts will be helpful for resistance management and control of this species. Copyright © 2010 Society of Chemical Industry
High resolution angle‐resolved photoemission spectroscopy on Cu‐based and Fe‐based high‐Tc superconductors
Authors: Zhou Xingjiang , Liu Guodong , Meng Jianqiao , Zhang Wentao , Liu Haiyun , Zhao Lin , Jia Xiaowen
Published: October 2010

Research on high temperature superconductivity has been a prominent topic in condensed matter physics. Angle‐resolved photoemission spectroscopy (ARPES) is a powerful technique in probing the electronic structure, energy gap and many‐body effects in high temperature superconductors, and other materials. In this paper, we first introduce our effort in developing vacuum ultra‐violet (VUV) laser‐based photoemission techniques, including angle‐resolved, spin‐resolved, time‐of‐flight electron energy analyzer‐based ones. Then, we highlight some of our recent results on Cu‐based high temperature superconductors utilizing our VUV laser‐based ARPES including many‐body effects in hole‐ and electron‐doped cuprates, superconducting gap and pseudogap, and the observation of Fermi pockets. In the last part of this paper, we briefly introduce our ARPES study on band structure, Fermi surface, superconducting gap, and many‐body effects in the newly discovered Fe‐based compounds.
Oscillatory clusterings in compartmentalized granular systems
Authors: Hou Meiying , Li Yinchang , Liu Rui , Zhang Yin , Lu Kunquan
Published: October 2010

A review is given of our previous work on the clustering, especially the oscillatory clustering for shaken fluidized granular matter in connected compartments, as examples for pattern formation and bifurcations in far from equilibrium systems. Flux model is presented and discussed for mono‐disperse and bi‐disperse granular systems. Comparison of the flux model with simulation results is given. They show reasonably well agreements. Besides the homogeneous (HOM), segregation (SEG), and oscillatory (OSC) states, two new stationary states (d‐OSC and s‐HOM) in the bi‐disperse granular system are predicted by our simulation. In our recent work these two new states are observed experimentally, and their flow diagrams are obtained based on the flux model, which shows qualitative agreement with the experimental results. Discussions of variations of the above system are also given, such as adding an asymmetric structure, changing the number of compartments from two to three, and adding more than two types of particles. This compartmentalized fluidized granular system turns out to be a good model system for studying nonlinear dynamics and pattern formation of far from equilibrium systems.
Glabridin, a phytoestrogen from licorice root, up‐regulates manganese superoxide dismutase, catalase and paraoxonase 2 under glucose stress
Authors: Yehuda Itamar , Madar Zecharia , Szuchman‐Sapir Andrea , Tamir Snait
Published: October 2010

The risk of death from cardiovascular diseases (CVDs), which are exacerbated by oxidative stress, is higher in diabetic women. This phenomenon has been attributed to the loss of estradiol‐vascular protection. Such knowledge led us to examine the potential of glabridin, a phytoestrogen, to substitute estradiol up‐regulation of antioxidant enzymes under high glucose conditions. Chronic glucose stress was found to down‐regulate catalase (CAT) and paraoxonase 2 (PON2) mRNA expression by 20% and 17%, respectively, and to decrease PON2 activity by 83% in macrophages. Inflammatory conditions had an additive effect on PON2 expression in a time‐dependent manner. Treatment with glabridin, under high glucose stress, increased PON2 activity by 60% and up‐regulated its mRNA expression by 3.5 fold. Furthermore, glabridin up‐regulated the expression of manganese superoxide dismutase (Mn‐SOD) and CAT in monocytes. In conclusion, glabridin has the potential of strengthening the antioxidant defense mechanism and may serve as an antiatherogenic agent in diabetes. Copyright © 2010 John Wiley & Sons, Ltd.
Grape seed extract enhances neurogenesis in the hippocampal dentate gyrus in C57BL/6 mice
Authors: Yoo Dae Young , Kim Woosuk , Yoo Ki‐Yeon , Lee Choong Hyun , Choi Jung Hoon , Yoon Yeo Sung , Kim Dong‐Woo , Won Moo‐Ho , Hwang In Koo
Published: October 2010

The effects of grape seed extract (GSE), a major source of phenolic compounds, were examined on cell proliferation, neuroblast differentiation and integration into granule cells in the hippocampal dentate gyrus (DG) of middle‐aged (12 month‐old) mice using Ki67, doublecortin (DCX) immunohistochemistry and 5′‐bromo‐2‐deoxyguanosine (BrdU)/calbindin D‐28k (CB) double immunofluorescence study, respectively. GSE (25, 50 and 100 mg/kg) was administered orally for 28 days, and the animals were treated with 50 mg/kg BrdU intraperitoneally on the day of first GSE treatment. In the vehicle‐treated group, Ki67 and DCX immunoreactivity was detected in the subgranular zone of the DG (SZDG). GSE treatment dose‐dependently increased the number of Ki67 and DCX immunoreactive cells, particularly the number of DCX immunoreactive neuroblasts with well‐developed (tertiary) dendrites. GSE also dose‐dependently increased DCX protein levels. In addition, GSE treatment increased significantly the number of BrdU/CB double labeled granule cells. These results suggest that GSE significantly increases cell proliferation, neuroblast differentiation and integration into granule cells in the DG, and the consumption of GSE enhances the plasticity of hippocampus in middle‐aged mice. Copyright © 2010 John Wiley & Sons, Ltd.
Protective effect of a polysaccharide isolated from a cultivated Cordyceps mycelia on hydrogen peroxide‐induced oxidative damage in PC12 cells
Authors: Shen Wenbin , Song Dan , Wu Jianyong , Zhang Weiyun
Published: October 2010

Cordyceps sinensis as a well‐known traditional Chinese tonic has many therapeutic functions. In the present study, an acid polysaccharide (APS) was isolated from cultivated Cordyceps mycelia by ion‐exchange and sizing chromatography. The protective capacity of APS against H2O2‐induced oxidative damage in rat pheochromocytoma PC12 cells was investigated by measuring cell viability, lactate dehydrogenase (LDH) release, antioxidant enzyme activity, malondialdehyde (MDA) levels and intracellular accumulation of reactive oxygen species (ROS) and Ca2+. The results demonstrated that pretreatment of PC12 cells with APS, prior to H2O2 exposure, significantly increased the survival of cells and the activities of glutathione peroxidase (GSH‐Px), catalase (CAT) and superoxide dismutase (SOD), and reduced the levels of LDH and MDA. Intracellular accumulation of reactive oxygen species (ROS) and Ca2+ were also inhibited by APS treatment. In conclusion, APS was found to increase the cellular antioxidant defence capacity, thereby protecting PC12 cells against oxidative stress. Copyright © 2010 John Wiley & Sons, Ltd.
Effect of ginsenosides Rg3 and Re on glucose transport in mature 3T3‐L1 adipocytes
Authors: Lee Ok‐Hwan , Lee Hee‐Hyun , Kim Ji‐Hyup , Lee Boo‐Yong
Published: October 2010

Ginsenosides, the active component of Panax ginseng, have been shown to evidence a variety of biological activities associated with hyperglycemia, obesity and type 2 diabetes mellitus. This study evaluated the effects of the ginsenosides, Rg3 and Re, on glucose uptake and the glucose transport system in mature 3T3‐L1 cells. The results demonstrated that the glucose uptake of ginsenosides Rg3 and Re at concentrations of 1–10 µM significantly increased by approximately ∼10% and ∼12%, respectively. Furthermore, the glucose transporter 4 (GLUT4) mRNA expression of ginsenosides Rg3 and Re at 10 µM was increased by approximately ∼1.73 and 1.43 fold, respectively. It was further confirmed in a series of experiments that ginsenosides Rg3 and Re stimulated the mRNA expression of insulin receptor substrate (IRS‐1) and the expression of phosphatidylinositol 3‐kinase (PI3K)‐110α protein, which is involved in downstream events in the insulin signaling pathway. These findings demonstrate that ginsenosides Rg3 and Re may stimulate glucose uptake via the PI3K pathways involving IRS‐1. Further, our results suggest that both of these ginsenosides might prove useful as effective antidiabetic and antihyperglycemic agents. Copyright © 2010 John Wiley & Sons, Ltd.
Sampling distributions of the Brier score and Brier skill score under serial dependence
Authors: Wilks D.S.
Published: October 2010

Relatively little attention has been given to the effects of serial correlation of forecasts and observations on the sampling properties of forecast verification statistics. An assumption of serial independence for low‐quality forecasts may be reasonable. However, forecasts of sufficient quality for autocorrelated events must themselves be autocorrelated: as quality approaches the limit of perfect forecasts, the forecasts become increasingly similar to the corresponding observations.

The effects of forecast serial correlation on the sampling properties of the Brier Score (BS) and Brier Skill Score (BSS), for probability forecasts of dichotomous events, are examined here. As in other settings, the effect of serial correlation is to inflate the variances of the sampling distributions of the two statistics, so that uncorrected confidence intervals are too narrow, and uncorrected hypothesis tests yield p‐values that are too small. Expressions are given for ‘effective sample size’ corrections for the sampling variances of both BS and BSS, in which it can be seen that the effects of serial correlation on the sampling variances increase with increasing forecast accuracy, and with decreasing climatological event probability. The sampling variance of BSS is more robust to serial correlation than that of BS. Hypothesis tests based on BSS are seen to be more powerful (i.e. more sensitive) than those based on BS, and substantially so for lower‐accuracy forecasts of lower‐probability events, for both serially correlated and temporally independent forecasts. Copyright © 2010 Royal Meteorological Society
A simulation model for improving the maintenance of high cost systems, with application to an offshore oil installation
Authors: Conn Andrew R. , Deleris Léa A. , Hosking Jonathan R. M. , Thorstensen Tom Anders
Published: October 2010

We describe a Generalized Semi‐Markov Model paired with Monte Carlo simulation that represents the evolution of the systems that constitute an offshore installation. We use the model to assess the performance of a maintenance plan in terms of a production penalty and unplanned shutdowns. In addition to estimating, comparing and improving maintenance plans, our approach enables the determination of the consequences of planning capital expenditures and installation modifications and the value of process improvements. Moreover, the entire framework is designed to be sufficiently flexible to accommodate various ‘what if’ scenarios in addition to other modifications. The simulation model was tested on data from an offshore oil installation, and was well received by the installation's operations personnel. Copyright © 2010 John Wiley & Sons, Ltd.
Isoelectric points of plasma‐modified and aged silicon oxynitride surfaces measured using contact angle titrations
Authors: Trevino Kristina J. , Shearer Jeffrey C. , McCurdy Patrick R. , Pease‐Dodson Shannon E. , Okegbe Christabel C. , Fisher Ellen R.
Published: October 2010

Acid‐base properties of metal oxides and polymers can control adhesion properties between materials, electrical properties, the physical structure of the material and gas adsorption behavior. To determine the relationships between surface isoelectric point, chemical composition and aging effects, plasma‐surface treatment of amorphous silicon oxynitride (SiOxNy) substrates was explored using Ar, H2O vapor, and NH3 inductively coupled rf plasmas. Overall, the Ar plasma treatment resulted in nonpermanent changes to the surface properties, whereas the H2O and NH3 plasmas introduced permanent chemical changes to the SiOxNy surfaces. In particular, the H2O plasma treatments resulted in formation of a more ordered SiO2 surface, whereas the NH3 plasma created a nitrogen‐rich surface. The trends in isoelectric point and chemical changes upon aging for one month suggest that contact angle and composition are closely related, whereas the relationship between IEP and composition is not as directly correlated. Copyright © 2010 John Wiley & Sons, Ltd.
Site‐oriented immobilization of fusion antigen directed by an affinity ligand, and its validation in an immunoassay
Authors: Feng Bo , Luo Yueping , Ge Fei , Wang Lu , Huang Liqun , Dai Youzhi
Published: October 2010

Immobilizing proteins on a solid surface in a site‐specific orientation and maintaining their bioactivity are crucial to the construction of high‐performance immunoassays. In this study, an affinity ligand for polystyrene (PS) surface screened from a phage display peptide library, named Lig1, was genetically fused to the N/C‐terminus of chimeric antigen HCV that could be recognized by specific antibodies against hepatitis C virus (HCV). Immunoassay characteristics of lig1‐fused HCVs immobilized on PS surface were compared to that of original HCV in both direct and indirect enzyme‐linked immunosorbent assay (ELISA). The results indicated that HCV‐Lig1 (Lig1 fused to HCV C‐terminus) was preferentially adsorbed on PS surface in a site‐oriented manner and would expose specific antibody‐binding sites well, which resulted in a substantial enhancement of detection sensitivity. AFM images showed that, compared to the original one, HCV‐Lig1 was arranged on PS surface in an ordered state and its conformational and steric distortions induced during the interfacial binding process were much slighter. As long as the specific epitope of a coating antigen is not located on both its N and C‐terminus, the ligand fusion approach could be an ideal strategy for site‐oriented protein immobilization. Copyright © 2010 John Wiley & Sons, Ltd.
Simplified column shortening analysis of a multi‐storey reinforced concrete frame
Authors: Kim Han‐Soo , Jeong Se‐Hun , Shin Seung‐Hak , Park Jae‐Pyo
Published: October 2010

An improved column shortening analysis method which can be used at the design stage of a tall building has been proposed. The proposed analysis method considers construction sequences, the restraining effect of horizontal members, as well as creep and shrinkage. The whole analysis period is divided into two phases: before completion and after completion, and correction factors are applied only to the before‐completion phase to consider the gradual nature of construction sequences. Age‐adjusted effective moduli of the horizontal members considering the long‐term behaviour of the members are used for more exact internal forces. Column shortenings of a 70‐storey reinforced concrete frame–shear wall building were investigated as a numerical example. It is shown that the proposed analysis method can be used effectively to evaluate the effects of the differential column shortening to the horizontal members at the design stage. Copyright © 2010 John Wiley & Sons, Ltd.
Computational Fluid Dynamics study on the performance and mechanism of suction control over a high‐rise building
Authors: Zheng Chao‐Rong , Zhang Yao‐Chun
Published: October 2010

In order to reduce the wind‐induced drag and improve the wind‐resistance performance of a high‐rise building, active suction control was proposed to investigate its drag‐reducing property through Computational Fluid Dynamics (CFD) method. The numerical method was validated by the experiment of suction control over a backward‐facing step flow. Effects of the dimensionless suction flux, the suction angle and the slot size on drag reduction for a high‐rise building model were analysed, and the detailed flow fields (including the time‐averaged stream and vorticity fields), the boundary layer development and turbulence characteristics like turbulent kinetic energy for the suction models were presented to discuss the mechanism of suction control. The results indicate that suction is very effective in reducing the wind‐load of a high‐rise building model, and only the dimensionless suction flux is important, while the orifice geometrical parameters and the suction velocities show little influence on drag reduction. The mechanism of suction control is concluded that suction can bring more flows around the windward face, restrain the flow separation and decrease the width of the wake for the suction models. Copyright © 2010 John Wiley & Sons, Ltd.
Effectiveness of active multiple‐tuned mass dampers for asymmetric structures considering soil–structure interaction effects
Authors: Li Chunxiang
Published: October 2010

Based on recent researches by Li et al. in 2009, the optimum parameter criterion of the AMTMD here is selected as minimizing the translational and torsional displacement mean square responses of the asymmetric structure with the AMTMD taking into account the SSI. The effectiveness criterion of the AMTMD is the ratio of the minimization of the translational and torsional displacement mean square responses of the asymmetric structure with the AMTMD to the translational and torsional displacement mean square responses of the asymmetric structure without the AMTMD considering the SSI. The investigations for the influences of the normalized eccentricity ratio (NER), torsional to translational frequency ratio (TTFR), relative stiffness of the soil to the structure (RSSS), and height‐to‐base ratio (HBR) of the soil‐asymmetric structure interaction system are then carried out on both the effectiveness and robustness of the AMTMD. A new basic result is that when an asymmetric structure is built on soft soil sites, the SSI needs to be considered to determine the optimal parameters of the AMTMD to avoid overestimating or underestimating its effectiveness. Likewise, the robustness of the AMTMD for asymmetric structures is underestimated if the SSI effect is left out of consideration. Copyright © 2010 John Wiley & Sons, Ltd.
A new algorithm for geometrical design of asymmetric tall buildings against seismic torsional behaviour
Authors: Şahin Abdurrahman
Published: October 2010

This paper presents a new algorithm developed to minimize the torsional effects in asymmetric tall buildings, through arriving at all possible orientations of rectangular columns that have different lateral stiffnesses and strength in two principal directions. The most suitable combination of different orientations of such columns are chosen for the design, which leads to minimum torsional effect. The developed algorithm is coded in MATLAB and the eccentricity of a given asymmetric tall building is minimized through the proposed algorithm. Three‐dimensional model of the building is constructed and its modal analysis is performed to obtain mode shapes using SAP2000 finite element program. Finite element model of the building is updated to eliminate the torsional moments by applying developed algorithm. Earthquake behaviour of the building is investigated using 1999 Kocaeli earthquake before and after this geometrical design. It is seen from the analysis results that the torsional moments are almost eliminated and the maximum principal stresses on shell elements are extremely reduced after system design depending on the proposed algorithm. In addition to this, it is realized that structural modal behaviour of the building is changed from torsional to translational. Copyright © 2010 John Wiley & Sons, Ltd.
The CUSUM test applied in prospective nuchal translucency quality review
Authors: Sabrià J. , Barceló‐Vidal C. , Arigita M. , Jimenez J. M. , Puerto B. , Borrell A.
Published: October 2010

Objectives

To design a cumulative sum (CUSUM) test for prospective nuchal translucency (NT) measurement quality review that is as stringent as the retrospective quality review methods based on distribution parameters currently in use.

Methods

The database including all fetal NT measurements obtained during a 2‐year period in a single center was reviewed, and measurements obtained by sonologists who measured fewer than 100 cases were excluded. The NT distribution parameters proposed by The Fetal Medicine Foundation (FMF) and the Women & Infants Hospital of Rhode Island (WIHRI) were assessed in the whole NT series and in sonologist‐specific distributions. A previously described CUSUM model was adapted to fulfil our objective.

Results

Two thousand four hundred and seventy‐five NT measurements were obtained by seven sonologists during the study period (January 2007–December 2008). In the assessment of sonologist‐specific NT distributions, two sonologists fulfilled all the FMF and WIHRI criteria, one showed NT overestimation and four failed due to NT underestimation. Our new CUSUM test model, based on multiples of the median deviations, showed good agreement with the FMF and WIHRI methods in the assessment of sonologist‐specific performance.

Conclusions

Our CUSUM test model showed close agreement with the retrospective quality review methods based on distribution parameters currently in use, but with the advantage that it can be applied prospectively, allowing for earlier correction of deviations from target performance. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Absent gallbladder on fetal ultrasound: prenatal findings and postnatal outcome
Authors: Shen O. , Rabinowitz R. , Yagel S. , Gal M.
Published: October 2010

Objectives

Fetal gallbladder non‐visualization on prenatal ultrasound in the second trimester is uncommon and in most cases the gallbladder is detected eventually. Associations of gallbladder non‐visualization with cystic fibrosis, aneuploidy, agenesis of the gallbladder and biliary atresia have been reported. We present our experience and review the literature.

Methods

During the study period from January 2004 to June 2009 we collected prospectively cases of non‐visualization of the fetal gallbladder in the second trimester. In each case the fetus was evaluated by two examiners on at least two occasions, at least a week apart. Cases with no additional sonographic malformations were designated as isolated. Further evaluation included follow‐up scans and a meticulous search for fetal anomalies. All patients were offered genetic consultation. Cystic fibrosis testing, amniocentesis for karyotyping and analysis of fetal digestive enzymes in the amniotic fluid were offered.

Results

We collected 21 cases of non‐visualization of the fetal gallbladder, 16 of which were isolated and five of which had additional malformations. In four of these five, the associated anomalies were severe and the pregnancies were terminated for aneuploidy (two cases of trisomy 18 and one triploidy) or for the severity of the associated anomalies. Associated anomalies included left isomerism with complex cardiac anomaly and intrauterine growth restriction with multisystem anomalies. The fifth fetus had interrupted inferior vena cava with azygos continuation without other anomalies and the child was alive and well at the age of 4 years. In 15 of the 16 isolated cases, antenatal and postnatal development were normal at the last follow‐up, ranging from 4 months to 2.5 years. One case of cystic fibrosis was diagnosed prenatally and this pregnancy was terminated. There were no diagnoses of abnormal karyotype or biliary atresia among cases of isolated non‐visualization of the gallbladder.

Conclusions

When prenatal non‐visualization of the fetal gallbladder is associated with other severe malformation, aneuploidy should be suspected. When it is isolated, if cystic fibrosis is ruled out, the outcome is good. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Congenital megalourethra: prenatal diagnosis and postnatal/autopsy findings in 10 cases
Authors: Amsalem H. , Fitzgerald B. , Keating S. , Ryan G. , Keunen J. , Pippi Salle J. L. , Berger H. , Aiello H. , Otaño L. , Bernier F. , Chitayat D.
Published: October 2010

Objective

Congenital megalourethra is a rare urogenital malformation characterized by dilation and elongation of the penile urethra associated with absence or hypoplasia of the corpora spongiosa and cavernosa. Postnatal complications include voiding and erectile dysfunction as well as renal insufficiency and pulmonary hypoplasia. To date, only a few prenatally diagnosed cases have been reported. We report on 10 cases diagnosed prenatally and their postnatal/autopsy findings.

Methods

The study involved retrospective chart review of all cases diagnosed antenatally in three tertiary care centers over 5 years. Antenatal ultrasound images and medical records from obstetrics, genetics, urology and nephrology were reviewed.

Results

Ten fetuses with megalourethra were identified at a median gestational age of 19 (range, 13–24) weeks and all were confirmed postnatally or at autopsy. Three pregnancies were terminated and seven continued. All cases presented with a distended bladder and megalourethra and all cases had normal karyotype. Of seven liveborn babies, one died neonatally of pulmonary hypoplasia. All six infants alive at the time of writing had a dysfunctional urethra and three suffered from impaired or end‐stage renal disease. Associated anomalies were found in half of the cases.

Conclusion

Congenital megalourethra is caused by abnormal development or hypoplasia of the penile erectile tissue, secondary to distal urethral obstruction. When the amniotic fluid volume is normal, survival is possible. However, all liveborn infants have voiding and renal dysfunction and sexual dysfunction is expected. Megalourethra should be considered in all male fetuses presenting prenatally with megacystis and detailed fetal ultrasonography should look for an elongated and/or distended phallic structure as well as any associated anomalies. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.
Ultrasound evaluation of the Cesarean scar: relation between a niche and postmenstrual spotting
Authors: Bij de Vaate A. J. M. , Brölmann H. A. M. , van der Voet L. F. , van der Slikke J. W. , Veersema S. , Huirne J. A. F.
Published: October 2010

Objective

To evaluate the relationship between a niche and abnormal uterine bleeding, and to develop a sonographic classification of niches and evaluate its relationship to abnormal uterine bleeding.

Methods

An observational prospective cohort study was performed between October 2007 and May 2009. All women who had a Cesarean section performed in our hospital were asked to participate. Two hundred and twenty‐five women were included and examined with both transvaginal sonography (TVS) and gel instillation sonohysterography (GIS) 6–12 months after the Cesarean section. In case of a niche, the depth, volume and residual myometrium were measured, and the shape was assessed according to a specified classification. A questionnaire and pictorial blood loss assessment chart were filled in.

Results

The prevalence of a niche on evaluation with TVS and GIS was 24.0% and 56.0%, respectively. A niche was considered to be present if the depth was at least 1 mm visualized with GIS. Postmenstrual spotting was reported by 33.6% of women with a niche and 15.2% of women without a niche (P = 0.002). The niche volume was significantly different between women with and without postmenstrual spotting (P = 0.02). Most niches had a semicircular (50.4%) or triangular shape (31.6%). No significant relationship was identified between the shape of the niche and postmenstrual spotting (P = 0.19).

Conclusions

A niche is present in 56.0% of women with a history of Cesarean section when examined by GIS and is associated with postmenstrual spotting. Semicircular and triangular niches are most common, but the shape is not related to postmenstrual spotting. Copyright © 2010 ISUOG. Published by John Wiley & Sons, Ltd.
Mechanisms in fetal bradyarrhythmia: 65 cases in a single center analyzed by Doppler flow echocardiographic techniques
Authors: Eliasson H. , Wahren‐Herlenius M. , Sonesson S.‐E.
Published: October 2010

Objective

Fetal bradyarrhythmias have various underlying mechanisms. As blocked atrial bigeminy (BB) generally resolves spontaneously, but incomplete atrioventricular block (AVB) might respond to steroid treatment, correct diagnosis is of major importance. Our objectives were to assess the underlying mechanisms in fetal bradyarrhythmia and the accuracy of Doppler techniques in differentiating between them.

Methods

Seventy‐eight patients referred to our tertiary center between 1990 and 2007 for evaluation of fetal bradycardia were analyzed retrospectively. Besides Doppler recordings from the mitral valve/aorta, superior vena cava/aorta and pulmonary vein/peripheral pulmonary artery, we used recordings from the pulmonary trunk and ductus venosus. We calculated the ratio of the time interval between conducted and consecutive blocked atrial contractions divided by the interval between two conducted atrial beats (acb/acc), to analyze more meticulously the atrial rhythm in BB and second‐degree AVB.

Results

Fetal bradycardia ( ≤ 110 bpm) was confirmed in 65 of the 78 referred cases. Twenty‐five had AVB (of which 20 were complete AVB), 29 had BB (of which 23 were intermittent) and 11 had sinus bradycardia. The bradyarrhythmic mechanism was identified correctly in all but one fetus with an atrial ectopic rhythm. Heart rates < 65 bpm were not seen in fetuses diagnosed with BB and rates < 60 bpm were seen only in cases with complete AVB, but heart rate did not distinguish between BB and AVB in the 60–75 bpm range. The acb/acc ratio clearly differentiated between fetsues with BB and those with second‐degree AVB, including during midgestation, when it was difficult to distinguish these fetuses.

Conclusions

Using Doppler flow recordings, the mechanism causing fetal bradycardia can be clarified. In most cases this can be accomplished by visual validation only, and meticulous measurements are needed mainly to distinguish midterm fetuses with BB from those with second‐degree AVB. Copyright © 2011 ISUOG. Published by John Wiley & Sons, Ltd.