bluuebunny/crossref_metadata_2025 huggingface dataset:
Inducible cardiomyocyte‐specific gene disruption directed by the rat Tnnt2 promoter in the mouse
Authors: Wu Bingruo , Zhou Bin , Wang Yidong , Cheng Hsiu‐Ling , Hang Calvin T. , Pu William T. , Chang Ching‐Pin , Zhou Bin
Published: December 2009

We developed a conditional and inducible gene knockout methodology that allows effective gene deletion in mouse cardiomyocytes. This transgenic mouse line was generated by coinjection of two transgenes, a “reverse” tetracycline‐controlled transactivator (rtTA) directed by a rat cardiac troponin T (Tnnt2) promoter and a Cre recombinase driven by a tetracycline‐responsive promoter (TetO). Here, Tnnt2‐rtTA activated TetO‐Cre expression takes place in cardiomyocytes following doxycycline treatment. Using two different mouse Cre reporter lines, we demonstrated that expression of Cre recombinase was specifically and robustly induced in the cardiomyocytes of embryonic or adult hearts following doxycycline induction, thus, allowing cardiomyocyte‐specific gene disruption and lineage tracing. We also showed that rtTA expression and doxycycline treatment did not compromise cardiac function. These features make the Tnnt2‐rtTA;TetO‐Cre transgenic line a valuable genetic tool for analysis of spatiotemporal gene function and cardiomyocyte lineage tracing during developmental and postnatal periods. genesis 48:63–72, 2010. © 2009 Wiley‐Liss, Inc.
Evidence that the C‐terminal domain (CtD) autoinhibits neural repression by Drosophila E(spl)M8
Authors: Kahali Bhaskar , Kim Jee‐Eun , Karandikar Umesh , Bishop Clifton P. , Bidwai Ashok P.
Published: December 2009

Analysis of the retinal defects of a CK2 phosphomimetic variant of E(spl)M8 (M8S159D) and the truncated protein M8* encoded by the E(spl)D allele, suggest that the nonphosphorylated CtD “autoinhibits” repression. We have investigated this model by testing for inhibition (in “trans”) by the CtD fragment in its nonphosphorylated (M8‐CtD) and phosphomimetic (M8SD‐CtD) states. In N+ flies, ectopic M8‐CtD compromises lateral inhibition, i.e., elicits supernumerary bristles as with loss of N signaling. This antimorphic activity of M8‐CtD strongly rescues the reduced eye and/or bristle loss phenotypes that are elicited by ectopic M8SD or wild type M8. Additionally, the severely reduced eye of Nspl/Y; E(spl)D/+ flies is also rescued by M8‐CtD. Rescue is specific to the time and place, the morphogenetic furrow, where “founding” R8 photoreceptors are specified. In contrast, the phosphomimetic M8SD‐CtD that is predicted to be deficient for autoinhibition, exhibits significantly attenuated or negligible activity. These studies provide evidence that autoinhibition by the CtD regulates M8 activity in a phosphorylation‐dependent manner. genesis 48:44–55, 2010. © 2009 Wiley‐Liss, Inc.
Generation of an EphA4 conditional allele in mice
Authors: Herrmann Julia E. , Pence Morgan A. , Shapera Emanuel A. , Shah Ravi R. , Geoffroy Cédric G. , Zheng Binhai
Published: December 2009

Ephrins and Eph receptor tyrosine kinases are cell‐surface molecules that serve a multitude of functions in cell–cell communication in development, physiology, and disease. EphA4 is a promiscuous member of the EphA subclass of Eph receptors and can bind to both EphrinAs and EphrinBs. In addition to its well‐established roles in guiding the development of neuronal connectivity, EphA4 has been implicated for a role in synaptic plasticity, vascular formation, axon regeneration, and central nervous system repair following injury. However, the study of its role in the adult stage has been hampered by confounding developmental defects in EphA4 germline mutants. Here, we report the generation and molecular characterization of an EphA4 conditional allele along with a novel null allele with a knockin fluorescent reporter gene (mCFP). The conditional allele will be useful in ascertaining postdevelopmental and/or cell type‐specific function of EphA4 in physiology, injury, and disease. genesis 48:101–105, 2010. © 2009 Wiley‐Liss, Inc.
Cyclic tests of four two‐story narrow steel plate shear walls—Part 1: Analytical studies and specimen design
Authors: Tsai Keh‐Chyuan , Li Chao‐Hsien , Lin Chih‐Han , Tsai Ching‐Yi , Yu Yi‐Jer
Published: December 2009

This study consists of two parts. In this two‐part research, four two‐story narrow steel plate shear walls (SPSWs) were cyclically tested at the Taiwan National Center for Research on Earthquake Engineering in 2007. This paper, Part 1, proposes a capacity design method for the first‐story boundary column of the SPSW to ensure that the plastic hinges form at the column bottom ends when the SPSW develops the plastic mechanism. The design method was developed based on the superposition method considering the frame sway action and the panel force effects of the SPSW. Restrained steel plate shear wall (R‐SPSW) studied herein adopts pairs of the horizontal restrainers sandwiching over both sides of the infill panels and connected to the boundary columns. Analytical studies on four SPSW example designs using nonlinear finite element (FE) models and the simplified strip models confirm that the restrainers could also effectively reduce the column force demands and allow the infill panel to stretch more uniformly. In addition, the FE analytical studies verify the effectiveness of the proposed column capacity design method and the seismic design recommendations for the restrainer. This paper introduces the designs of the four narrow SPSW specimens, presenting the selections of the boundary beams and columns, the designs of the beam‐to‐column connections and the construction details of the restrainers. The experimental results, key observations and the design implications are reported in the companion paper. Copyright © 2009 John Wiley & Sons, Ltd.
Test method for concrete spalling using small electric furnace
Authors: Zhao Ren , Sanjayan Jay G.
Published: December 2009

Concrete spalling can cause severe damage to concrete structure when exposed to fire. The spalling mechanisms are not very well understood. For the testing of spalling, full‐scale structural members should be used, as spalling tests are sensitive to size effects. Full‐scale testing in large furnace is costly and is not suitable for testing large number of concrete mixture trials. The standard and hydrocarbon fire time–temperature curves have rapid temperature rise during the initial phase. This temperature rise requires a gas furnace with high heating capacity and cannot be generated by electric muffle furnace commonly available in many laboratories.

This paper presents a method to carry out spalling test in small‐scale specimens with exposure to rapid temperature rise using a commonly available electric furnace in the laboratories. The tests are based on 150 mm diameter cylinders that are laterally confined to simulate full‐scale structural members. The cylinder surface is exposed to rapid temperature rise by exposing through vertical and/or horizontal holes in pre‐heated small electric furnace. Some unconfined 100 mm diameter cylinders were also exposed horizontally to test the performance of confinement. The paper shows that the hydrocarbon fire and standard fire exposure can be simulated by manipulating the exposure location of the surface of the concrete cylinder. Ordinary Portland cement concrete cylinders with different strengths were tested and different spalling patterns were observed. The spalling patterns matched the test results from a gas furnace fire test simulating the fire curves. The tests demonstrated that the method is an effective and convenient technique to predict the spalling risk of a concrete. Copyright © 2009 John Wiley & Sons, Ltd.
Hippocampal signals for strong memory when associative memory is available and when it is not
Authors: Wais Peter E.
Published: December 2009

The paired‐associate task has been used with functional magnetic resonance imaging (fMRI) in studies that assessed the role of the medial temporal lobe (MTL) subserving recollection and familiarity. Some researchers have interpreted their results to mean that the hippocampus selectively subserves recollection and not familiarity [cf., Eichenbaum et al., (2007) Annu Rev Neurosci 30:123–152]. Yet many of these results confound recollection and familiarity with strong and weak memories, and it is not clear whether the conclusions represent differences between memory processes or memory strength. In the current study, participants were scanned with fMRI during retrieval in a paired‐associate task, and a new approach separated the analysis of memory strength from the analysis of memory processes. The data were sorted by confidence level in an old/new task, and the high‐confidence responses were compared in categories when associative memory was highly accurate and when it was not available. The results show that high‐confidence memory produced increased activity in the hippocampus, relative to the level for forgotten pairs, both when associative memory was available and when it was not. Two interpretations are discussed for the behavioral results for when associative memory was not available: one account based on familiarity and the other account based on noncriterial recollection. The conclusion is that recognition of the word‐pairs was based on familiarity when associative memory was not available. Together with the fMRI results that activity in two regions associated with cognitive control (left ventrolateral prefrontal cortex and left inferior parietal lobule) was greater when responses were based on associative memory than when based on familiarity, the findings suggest that the hippocampus supports strong memory and that cortical regions make an additional contribution to recollection. © 2009 Wiley‐Liss, Inc.
Phosphacan and receptor protein tyrosine phosphatase β expression mediates deafferentation‐induced synaptogenesis
Authors: Harris Janna L. , Reeves Thomas M. , Phillips Linda L.
Published: December 2009

This study documents the spatial and temporal expression of three structurally related chondroitin sulfated proteoglycans (CSPGs) during synaptic regeneration induced by brain injury. Using the unilateral entorhinal cortex (EC) lesion model of adaptive synaptogenesis, we documented mRNA and protein profiles of phosphacan and its two splice variants, full length receptor protein tyrosine phosphatase β (RPTPβ) and the short transmembrane receptor form (sRPTPβ), at 2, 7, and 15 days postlesion. We report that whole hippocampal sRPTPβ protein and mRNA are persistently elevated over the first two weeks after UEC. As predicted, this transmembrane family member was localized adjacent to synaptic sites in the deafferented neuropil and showed increased distribution over that zone following lesion. By contrast, whole hippocampal phosphacan protein was not elevated with deafferentation; however, its mRNA was increased during the period of sprouting and synapse formation (7d). When the zone of synaptic reorganization was sampled using molecular layer/granule cell (ML/GCL) enriched dissections, we observed an increase in phosphacan protein at 7d, concurrent with the observed hippocampal mRNA elevation. Immunohistochemistry also showed a shift in phosphacan distribution from granule cell bodies to the deafferented ML at 2 and 7d postlesion. Phosphacan and sRPTPβ were not colocalized with glial fibrillary acid protein (GFAP), suggesting that reactive astrocytes were not a major source of either proteoglycan. While transcript for the developmentally prominent full length RPTPβ was also increased at 2 and 15d, its protein was not detected in our adult samples. These results indicate that phosphacan and RPTPβ splice variants participate in both the acute degenerative and long‐term regenerative phases of reactive synaptogenesis. These results suggest that increase in the transmembrane sRPTPβ tyrosine phosphatase activity is critical to this plasticity, and that local elevation of extracellular phosphacan influences dendritic organization during synaptogenesis. © 2009 Wiley‐Liss, Inc.
Dynamics of hippocampal spatial representation in echolocating bats
Authors: Ulanovsky Nachum , Moss Cynthia F.
Published: December 2009

The “place fields” of hippocampal pyramidal neurons are not static. For example, upon a contextual change in the environment, place fields may “remap” within typical timescales of ∼1 min. A few studies have shown more rapid dynamics in hippocampal activity, linked to internal processes, such as switches between spatial reference frames or changes within the theta cycle. However, little is known about rapid hippocampal place field dynamics in response to external, sensory stimuli. Here, we studied this question in big brown bats, echolocating mammals in which we can readily measure rapid changes in sensory dynamics (sonar signals), as well as rapid behavioral switches between distal and proximal exploratory modes. First, we show that place field size was modulated by the availability of sensory information, on a timescale of ∼300 ms: Bat hippocampal place fields were smallest immediately after an echolocation call, but place fields “diffused” with the passage of time after the call, when echo information was no longer arriving. Second, we show rapid modulation of hippocampal place fields as the animal switched between two exploratory modes. Third, we compared place fields and spatial view fields of individual neurons and found that place tuning was much more pronounced than spatial view tuning. In addition, dynamic fluctuations in spatial view tuning were stronger than fluctuations in place tuning. Taken together, these results suggest that spatial representation in mammalian hippocampus can be very rapidly modulated by external sensory and behavioral events. © 2009 Wiley‐Liss, Inc.
Long‐term visuospatial retention unaffected by fornix transection
Authors: Chai Kwok Sze , Buckley Mark J.
Published: December 2009

As part of an earlier experiment (Kwok and Buckley, 2009), six macaque monkeys (three with fornix transection and three unoperated controls) were trained postoperatively to discriminate a total of 104 new concurrent visuospatial conditional problems to criterion. Our experiment measured and compared long‐term retention of these problems with two separate one‐trial postoperative retention tests administered 3 and 15 months, respectively, after acquisition. All animals showed some degree of forgetting of these problems but all remembered above chance levels, even after 15 months. The amount forgotten by each group did not differ significantly at either time point. These results show that long‐term retention of visuospatial information is independent of the fornix. Similarities in resistance to forgetting are drawn between fornix‐transected macaques and patients with amnesia and the implications for clinical rehabilitation are discussed. © 2009 Wiley‐Liss, Inc.
Biotransformation of rifamycin B to rifamycin S using immobilised whole cells of Humicola spp. in a fluidised bed reactor
Authors: Lee Gyun M. , Choi Cha Y. , Park Jong M. , Han Moon H.
Published: December 2009

The biotransformation of rifamycin B to rifamycin S using immobilised whole cells of a Humicola sp. in a fluidised bed reactor exhibited a linear relationship between loading of the immobilised whole cells and conversion, in both batch and continuous operations; the conversion of rifamycin B was higher in batch than continuous operation for a given residence time. The immobilised whole cells were obtained by copolymerisation of the acetone‐dried cells with acrylamide. They showed maximum activity at pH 7.8 and 50°C. It was found that aeration effects on the reaction in continuous operation were different from those in batch operation for the same residence time. In batch operation, the conversion of rifamycin B to rifamycin S increased with increased rate of aeration and reached a constant maximum value at aeration rates above 20.8 vvm. In continuous operation, the steady state conversion reached a maximum value in the range of aeration rate between 5.8 and 12.5 vvm; beyond this range the steady state conversion decreased steadily owing to cell leakage. The half life for the operational stability at 40°C was about 13 h.
Enzyme immobilisation within insolubilised gelatin
Authors: Alteriis Elisabetta De , Parascandola Palma , Salvadore Sonia , Scardi Vincenzo
Published: December 2009

A method originally developed for entrapping invertase‐active yeast cells (Saccharomyces cerevisiae) in gelatin has been extended to enzymes. Six enzymes belonging to three different classes were immobilised in gelatin made insoluble by formaldehyde. The activity yield of the resulting immobilised enzyme preparations ranged from 9.6 to 48.0%. These values, however, can be roughly doubled by crushing the immobilised enzyme particles into very small fragments, thus indicating that independently of enzyme sensitivity to formaldehyde or of enzyme interaction with gelatin, the limiting factor is mass transfer resistance to diffusion of substrate into the insolubilised gelatin matrix.
Solubilisation of gold by Cuhromobacterium violaceum
Authors: Smith Anthony D. , Hunt Raymond J.
Published: December 2009

Chromobacterium violaceum, a cyanogenic bacterium, has been shown to solubilise up to 215 parts × 10−6 gold from 1000 parts × 10−6 of the pure metal after 40 days incubation in nutrient medium. Cyanide is produced during the growth and stationary phase of culture and the solubilised gold species has been shown to be the complex anion [Au(CN)2]−.
Bioelectrochemical fuel‐cells operated by the cyanobacterium, Anabaena variabilis
Authors: Tanaka Kazuko , Tamamushi Reita , Ogawa Teruo
Published: December 2009

Substantial electric output was delivered from the bioelectrochemical fuel‐cells operated under anaerobic conditions by Anabaena variabilis strain M‐2 and 2‐hydroxy‐1,4‐naphthoquinone. There was a linear relationship between the coulombic output of the fuel‐cells operated in the dark and the glycogen content of the organisms. The coulombic output was increased substantially in the light; the increase was observed even in the absence of CO2. Oxygen was evolved by Anabaena cells under the operating conditions of the fuel‐cells. The results demonstrated that the source of electricity obtained from the fuel‐cells is endogenous glycogen in the dark and both glycogen and electrons produced by photosynthetic oxidation of water in the light.
The effect of pretreatment on the enzymic hydrolysis of cellulosic industrial waste
Authors: Toussaint Pierre , Bataille Pierre F.
Published: December 2009

The enzymic hydrolysis of cellulosic waste material from industrial origins using commercial Tricoderma viride cellulase gave yields approaching 80% conversion following pretreatments. The yield was a function of the purity of the substrate and the pretreatments imposed. These included sterilisation, heating, ball‐milling and alkali treatment. Highest yields of glucose or enzyme hydrolysis were achieved with a 4% solka floc suspension following pretreatment in 5% alkali, when the enzyme mix was 0.22IU cm−3 of filter paper activity, 0.07IU cm−3Cx enzyme activity and 0.14IU cm−3 of β‐glucosidase activity. Kraft pulp also gave up to 75% yields by this method.
Achieving a Safety Culture in Obstetrics
Authors: DuPree Erin , O'Neill Loraine , Anderson Rebecca M.
Published: December 2009

Preventable maternal and neonatal mortalities still occur, despite the wonders of today's technologically advanced healthcare system. Delivering high‐quality, consistent care is the goal of every provider. Yet, obstetrical practice, in which unpredictable events and high‐risk situations are the norm, is particularly vulnerable to medical errors. Obstetrics departments should be striving for a climate of patient safety, one that includes a just, reporting, and learning culture. This article discusses the various components of a safety culture as well as some of the advances that are being made in the field to improve the quality of care in obstetrics. Mt Sinai J Med 76:529‐538, 2009. © 2009 Mount Sinai School of Medicine
Emerging Roles of Kruppel‐Like Factor 6 and Kruppel‐Like Factor 6 Splice Variant 1 in Ovarian Cancer Progression and Treatment
Authors: DiFeo Analisa , Narla Goutham , Martignetti John A.
Published: December 2009

Epithelial ovarian cancer is one of the most lethal gynecologic cancers and the fifth most frequent cause of female cancer deaths in the United States. Despite dramatic treatment successes in other cancers through the use of molecular agents targeted against genetically defined events driving cancer development and progression, very few insights into epithelial ovarian cancer have been translated from the laboratory to the clinic. If advances are to be made in the early diagnosis, prevention, and treatment of this disease, it will be critical to characterize the common and private (personalized) genetic defects underlying the development and spread of epithelial ovarian cancer. The tumor suppressor Kruppel‐like factor 6 and its alternatively spliced, oncogenic isoform, Kruppel‐like factor 6 splice variant 1, are members of the Kruppel‐like zinc finger transcription factor family of proteins, which have diverse roles in cellular differentiation, development, proliferation, growth‐related signal transduction, and apoptosis. Inactivation of Kruppel‐like factor 6 and overexpression of Kruppel‐like factor 6 splice variant 1 have been associated with the progression of a number of human cancers and even with patient survival. This article summarizes our recent findings demonstrating that a majority of epithelial ovarian cancer tumors have Kruppel‐like factor 6 allelic loss and decreased expression coupled with increased expression of Kruppel‐like factor 6 splice variant 1. The targeted reduction of Kruppel‐like factor 6 in ovarian cancer cell lines results in marked increases in cell proliferation, invasion, tumor growth, angiogenesis, and intraperitoneal dissemination in vivo. In contrast, the inhibition of Kruppel‐like factor 6 splice variant 1 decreases cellular proliferation, invasion, angiogenesis, and tumorigenicity; this provides the rationale for its potential therapeutic application. These results and our recent demonstration that the inhibition of Kruppel‐like factor 6 splice variant 1 can dramatically prolong survival in a preclinical mouse model of ovarian cancer are reviewed and discussed. Mt Sinai J Med 76:557‐566, 2009. © 2009 Mount Sinai School of Medicine
Current Surgical Management of Ulcerative Colitis
Authors: Grucela Alexis , Steinhagen Randolph M.
Published: December 2009

Inflammatory bowel disease is divided into 2 major disease entities: Crohn's disease and ulcerative colitis. Ulcerative colitis is characterized by contiguous inflammation of the colorectal mucosa, always beginning in and involving the rectum and progressing for variable distances proximally within the colon. In ulcerative colitis, medical therapy, which is not curative, is directed at controlling symptoms and reducing the underlying inflammatory process. However, emergent or elective removal of the colon and rectum does cure the disease and also eliminates the possibility of developing a malignancy. Here we present the current surgical treatment of ulcerative colitis and issues in the management of ulcerative colitis. We discuss indications for surgical treatment, elective and emergent operative management, early and late complications of surgery, and functional results. Mt Sinai J Med 76:606‐612, 2009. © 2009 Mount Sinai School of Medicine
Erratum: Quantification of water diffusion and relaxation times of human U87 tumors in a mouse model
Authors: Sun Yanping , Mulkern Robert V. , Schmidt Karl , Doshi Sameer , Albert Mitchell S. , Schmidt Nils O. , Ziu Mateo , Black Peter , Carrol Rona , Kieran Mark W.
Published: December 2009

This paper (DOI: 10.1002/nbm.894) was published online on 22 September 2004 and was included in the October issue of that year (Vol. 17, no. 6, pp. 399–404).

An error in the text has recently been discovered. The Experimental section on p. 400 should read as follows:

For intracranial implantation, 1 × 105 U87 cells suspended in 10 µl of sterile phosphate‐buffered saline (PBS) were injected into the right frontal hemisphere (3 mm anterior to the Bregma, 2 mm from the midline, and 3 mm deep) of all animals using a stereotactic fixation device (Stoelting, Wood Dale, IL, USA).
The functions and norms that drive university student volunteering
Authors: Francis Julie E.
Published: December 2009

Young adult volunteers are vital to the current and future operations of nonprofit organizations yet many countries report low and declining volunteer participation by this group. Moreover, university students are a particularly under‐utilized and under‐researched segment of potential young adult volunteers. As such, the current study examines the functions and norms that drive university students to volunteer. A survey of 282 students indicates that the Volunteer Functions Inventory (VFI) does not adequately explain the volunteering of today's university students. For instance, t‐tests reveal that the importance of the VFI functions among current students differs significantly to the importance of the functions among the previous generation of students. Also, factor analysis shows that the structure of the VFI model is unstable for the current sample while multiple regression reveals that the VFI explains only 11% of university student volunteering. In contrast, χ2‐tests indicate that volunteering by university students is dependent on the observed volunteering of primary reference group members (i.e., parents, siblings, close friends). The results suggest that nonprofit organizations may need to revise their recruitment strategies for today's university students: rather than appealing to the functional benefits of volunteering, positioning volunteering as the ‘normal’ thing to do may be more successful. Further research is needed to develop a richer understanding of reference group influences on the volunteering behavior of today's young adults.

Copyright © 2009 John Wiley & Sons, Ltd.
Influence of solution properties on the roller electrospinning of poly(vinyl alcohol)
Authors: Cengiz Funda , Dao Tuan Anh , Jirsak Oldrich
Published: December 2009

In recent years, nanofiber production via electrospinning has gained importance because of superior properties of submicron fibers. In this study, the effect of molecular weight, concentration of solution, electric conductivity, surface tension and solution viscosity of the polymer solution on the roller electrospinning of PVA nanofibers was investigated. One nonspinnable and two spinnable polymer species were studied. The effect of polymer concentration and solution viscosity on the electrospinning process throughput, fiber diameters and quality of nanofiber layers was measured. According to the results there is a significant difference in rheological behavior of nonspinnable and spinnable polymer solutions. Electric conductivity and surface tension of the solutions did not influence both throughput and fiber diameter significantly. Whereas molecular weight has an important effect on the spinnability, concentration of the solutions has not. On the contrary, concentration influences the process throughput considerably and properties of nanofibers and nanofiber layers to some extent. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
A prospective investigation of teacher preference and children's perceptions of the student–teacher relationship
Authors: Mercer Sterett H. , DeRosier Melissa E.
Published: December 2009

This study investigated teacher preference, the degree to which a teacher likes a specific student, as a predictor of students' perceptions of teacher preference as well as conflict and support in the student–teacher relationship. Child and teacher reports of teacher preference and child reports of conflict and support were provided in the fall and spring of one academic year. Participants included 1,104 fourth‐grade students in 10 schools. Results indicated that teacher preference predicted change in children's perceived teacher preference. In addition, lower levels of teacher preference directly predicted higher subsequent levels of conflict, but not support. Because teacher preference and children's perceptions of teacher preference were related, lower levels of teacher preference also indirectly predicted higher levels of conflict and lower levels of support. Discussion focuses on the implications of the findings from a dyadic systems conceptualization of student–teacher relationships. © 2009 Wiley Periodicals, Inc.
Study of a lipophilic captopril analogue binding to angiotensin I converting enzyme
Authors: Dalkas Georgios A. , Marchand Damien , Galleyrand Jean‐Claude , Martinez Jean , Spyroulias Georgios A. , Cordopatis Paul , Cavelier Florine
Published: December 2009

Human ACE is a central component of the renin–angiotensin system and a major therapeutic target for cardiovascular diseases. The somatic form of the enzyme (sACE) comprises two homologous metallopeptidase domains (N and C), each bearing a zinc active site with similar but distinct substrate and inhibitor specificities. In this study, we present the biological activity of silacaptopril, a silylated analogue of captopril, and its binding affinity towards ACE. Based on the recently determined crystal structures of both the ACE domains, a series of docking calculations were carried out in order to study the structural characteristics and the binding properties of silacaptopril and its analogues with ACE. Copyright © 2009 European Peptide Society and John Wiley & Sons, Ltd.
Control of charge separation by electric field manipulation in polymer‐oxide hybrid organic photovoltaic bilayer devices
Authors: White Matthew S. , Olson Dana C. , Kopidakis Nikos , Nardes Alexandre M. , Ginley David S. , Berry Joseph J.
Published: December 2009

Hybrid polymer/oxide organic photovoltaic (h‐OPV) devices have the potential to replace the organic acceptor component with an inorganic, nano‐structured oxide. This approach leverages the positive attributes of inorganic materials while maintaining the potential processing advantages of organic electronics. By manipulating the carrier concentration of the oxide acceptor layer in bilayer h‐OPV devices, we demonstrate control of the electric field at the planar donor–acceptor interface. The effects of the electric field can be observed in both the JSC and the fill factor of the h‐OPV devices. Furthermore, interfacial layers of TiOx are used on ZnO to prevent recombination of geminate electron–hole pairs. It is shown that interfacial TiOx successfully inhibits recombination only when the electric field is strong enough to sufficiently transfer charges to the ZnO layer. If the interfacial electric field is insufficient, then the TiOx instead serves to enhance recombination at the donor–acceptor interface.
Hydrogen implantation‐induced large area exfoliation in AlN epitaxial layers
Authors: Dadwal U. , Scholz R. , Kumar P. , Kanjilal D. , Christiansen S. , Gösele U. , Singh R.
Published: December 2009

Hydrogen ion implantation in aluminium nitride (AlN) epitaxial layers grown on 2‐inch c‐plane (0001) sapphire substrates was performed with different fluences in the range of 1 × 1017–2 × 1017/cm2 at various implantation temperatures between liquid nitrogen (LN2) to 300 °C. The post‐implantation thermal annealing behaviour of these samples was studied by using optical microscopy, atomic force microscopy (AFM) and transmission electron microscopy (TEM). Our investigations showed that AlN samples that were implanted at LN2 and room temperature (RT) exhibited mostly surface blistering after post‐implantation annealing. On the other hand, the AlN samples that were implanted at 100 and 300 °C showed large area exfoliation of the implanted surface after post‐implantation annealing. The implantation‐induced damage in AlN was analysed by cross‐sectional TEM, which revealed a damage band inside the AlN layer in all the cases that was decorated with hydrogen‐filled nanovoids. These nanovoids showed a greater tendency of agglomerating together to form nanocracks in the as‐implanted state for 100 and 300 °C implanted samples leading eventually to the large area exfoliation after high temperature annealing.
The competition between the intramolecular hydrogen bond and π‐electron delocalization in trifluoroacetylacetone—A theoretical study
Authors: Nowroozi Alireza , Roohi Hossain , Sadeghi Ghoogheri Mohammad Sadegh , Sheibaninia Mohseneh
Published: December 2009

Conformational study of trifluoroacetylacetone was carried out using the HF, B3LYP, and MP2 methods with the 6‐31G(d, p) and 6‐311++G(d, p) basis sets. All of the results show that the chelated enol structures (E11 and E31) have extra stability with respect to the other forms and one of them (E11) is global minimum. The energy gap between the chelated forms is in the range 0.7–5.9 kJ mol−1. Theoretical calculations show that this compound has an asymmetric double minimum potential energy surface which is in contrast with the electron diffraction result. Moreover, the computational results predict that due to the withdrawing effect of CF3group, hydrogen bond in trifluoroacetylacetone is weaker than the acetylacetone. Because of the more stability of E11, it is expected that the hydrogen bond energy in E11 is greater than the E31, but at all of the computational levels with most extended basis set the converse results were observed. These results clearly show that the hydrogen bond is not a superior parameter in conformational preference and the contribution of resonance is probably greater than the hydrogen bond. Finally, the analysis of this system by quantum theory of atoms in molecules and natural bond orbital methods fairly support the ab initio results. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Theoretical studies on electronic structure and magnetic properties of mixed‐valence uteroferrin active site
Authors: Koizumi Kenichi , Shoji Mitsuo , Yamaguchi Kizashi , Nakamura Haruki , Takano Yu
Published: December 2009

The electronic structure and magnetic interaction of the active site of pig purple acid phosphatase (PAP, uteroferrin) were investigated using pure DFT (UBLYP) and hybrid DFT methods (UB3LYP and UB2LYP). Uteroferrin catalyzes the hydrolysis of a phosphate ester under acidic conditions and contains a binuclear iron center. The mammalian PAPs are expected to be targets for drug design of osteoporosis. Their active sites are typical examples of the Fe(II)‐Fe(III) mixed‐valence system. We studied double exchange interaction of the mixed‐valence system, using the potential energy difference between the Fe(II)‐Fe(III) and the Fe(III)‐Fe(II) states. The pathway of the antiferromagnetic coupling between Fe(III) and Fe(II) were also discussed by using chemical indices, which are evaluated by the occupation numbers of singly occupied natural orbitals. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Computational investigation of wave packet scattering in the complex plane: Numerical analytic continuation techniques
Authors: Rowland Brad A. , Wyatt Robert E.
Published: December 2009

In this study, we utilize Numerical Analytic Continuation (NAC) techniques to compute the complex‐extension of wave packets computed on the real‐axis. Various methods for doing this are reviewed, and the accuracy and stability of one particular method (the Cauchy Method) are examined using a test function. We focus on generating numerically accurate maps of the complex‐extended time‐dependent wave packet for the Gaussian and Eckart barrier scattering problems. We also examine quantum momentum function vector fields and the associated Pólya vector fields for this problem. In a companion study, we present a novel method for solving the complex‐extended Schrödinger equation for points in the complex plane for wave packet scattering from a Gaussian barrier. Several fascinating features of the solution (such as quantized vortices) were presented, but we could only check the veracity of those results on the real‐axis. The method utilized in this study provides an additional check of these results. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Spin‐free quantum electronic structure: Its second quantization and para‐Fermionics
Authors: Klein D. J.
Published: December 2009

First, the spin‐free formulation of electronic structure is reviewed within the standard first‐quantized framework, with special attention to its manner of correspondence to the standard antisymmetrized space‐spin (ASspin) formulation. Second, within this first‐quantized framework, note is made of some “discrepancies” in the correspondence, for example, regarding mismatches of symmetry‐related degeneracies. Third, a novel second‐quantized spin‐free formulation is introduced to overcome these “discrepancies,” and so achieve a one‐to‐one correspondence between ASspin wave functions and second‐quantized spin‐free wave functions. Yet further, this second‐quantized spin‐free description enables the identification of electrons as “para‐Fermions,” at least in the nonrelativistic limit of spin‐free interactions. From the point of view of elementary particle physics, a rather complete picture of the behavior of para‐Fermions emerges with electrons as a proxy, and so suggests that in fact para‐Fermions would be difficult to distinguish from ordinary Fermions, at least in this nonrelativistic limit or with but few such particles. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Anodic film formation on binary AlMg and AlTi alloys in nitric acid
Authors: Garcia‐Garcia F. J. , Koroleva E. V. , Thompson G. E. , Smith G. C.
Published: December 2009

Nitric acid is commonly used for surface treatments of aluminium alloys. It is used to clean the surfaces after alkaline etching; it has application in chemical polishing and is also used for electrograining. The majority of these treatments undergo the application of anodic polarisation that results in formation of anodic oxide film. However, little is known about the behaviour of aluminium containing magnesium or titanium in solid solution under such conditions. To reveal the effects of magnesium and titanium alloying additions on anodic film formation in nitric acid, Al‐1800 ppm Mg and Al‐800 ppm Ti alloys were investigated. It was found that porous alumina film developed on the surfaces with reduced efficiency of 40%, due to the reactive nature of nitric acid to alumina. The presence of magnesium and titanium in aluminium had little influence on the efficiency of film growth, as confirmed by the relatively similar thicknesses of oxide formed on binary alloys and aluminium. However, incorporation of magnesium ions into the alumina film led to development of a high‐population density of localised voids near the alloy/film interface. An increased titanium content was found in the film regions close to the alloy/film interface, indicating its oxidation. Copyright © 2009 John Wiley & Sons, Ltd.
Transvaginal cervical length measurement for prediction of preterm birth in women with threatened preterm labor: a meta‐analysis
Authors: Sotiriadis A. , Papatheodorou S. , Kavvadias A. , Makrydimas G.
Published: December 2009

Objectives

To integrate data on the performance of cervical length measurement for the prediction of preterm birth in symptomatic women.

Methods

MEDLINE, SCOPUS and manual searches for studies with transvaginal ultrasound measurement of the cervical length in symptomatic women were carried out. Random effects models were used for data integration, and pooled test estimates of sensitivity, specificity, and positive and negative likelihood ratios (LR+ and LR−) were calculated along with their 95% CIs.

Results

Twenty‐eight studies fulfilled the selection criteria. For birth within 1 week from presentation, the pooled sensitivity, specificity, LR+ and LR− of cervical length < 15 mm were 59.9% (95% CI, 52.7–66.8%), 90.5% (95% CI, 89.0–91.9%), 5.71 (95% CI, 3.77–8.65) and 0.51 (95% CI, 0.33–0.80), respectively. The same estimates for studies with presentation at or before 34 + 0 weeks were 71.0% (95% CI, 60.6–79.9%), 89.8% (95% CI, 87.4–91.9%), 5.19 (95% CI, 2.29–11.74) and 0.38 (95% CI, 0.11–1.34), respectively. For prediction of birth before 34 weeks, the pooled sensitivity, specificity, LR+ and LR− of cervical length < 15 mm were 46.2% (95% CI, 34.8–57.8%), 93.7% (95% CI, 90.7–96.0%), 4.31 (95% CI, 2.73–6.82) and 0.63 (95% CI, 0.38–1.04), respectively. There was considerable heterogeneity across studies in most estimates.

Conclusions

Measurement of cervical length in symptomatic women can detect a significant proportion of those who will deliver within 1 week and help to rationalize their management. The considerable heterogeneity across studies may be indicative of methodological flaws, which either were not reported at all or were under‐reported. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Application of a LES technique to characterize the wake deflection of a wind turbine in yaw
Authors: Jiménez Ángel , Crespo Antonio , Migoya Emilio
Published: December 2009

When a wind turbine works in yaw, the wake intensity and the power production of the turbine become slightly smaller and a deflection of the wake is induced. Therefore, a good understanding of this effect would allow an active control of the yaw angle of upstream turbines to steer the wake away from downstream machines, reducing its effect on them. In wind farms where interaction between turbines is significant, it is of interest to maximize the power output from the wind farm as a whole and to reduce fatigue loads on downstream turbines due to the increase of turbulence intensity in wakes. A large eddy simulation model with particular wind boundary conditions has been used recently to simulate and characterize the turbulence generated by the presence of a wind turbine and its evolution downstream the machine. The simplified turbine is placed within an environment in which relevant flow properties like wind speed profile, turbulence intensity and the anisotropy of turbulence are found to be similar to the ones of the neutral atmosphere. In this work, the model is used to characterize the wake deflection for a range of yaw angles and thrust coefficients of the turbine. The results are compared with experimental data obtained by other authors with a particle image velocimetry technique from wind tunnel experiments. Also, a comparison with simple analytical correlations is carried out. Copyright © 2009 John Wiley & Sons, Ltd.
Gust load reduction concept in wind turbines
Authors: Grzędziński Janusz , Arkadiusz Arkadiusz
Published: December 2009

A concept is presented of gust alleviation in wind turbines by using the blade aerodynamic torsional moment as an actuator for forcing the blade to feather in order to reduce aerodynamic loads. The pitching to feather is implemented through a temporary release of the blade‐hub torsional connection after that the blade rotates freely until it reaches the assumed pitch angle. To describe this process, a simple wind turbine model with three elastic blades is formulated and some numerical simulations are performed. The results of the simulations include, among others, the time‐history of the out‐of‐plane blade bending moment in response to the uniform gust, showing that, in this way, it is possible—at least theoretically—to reduce this moment by approximately 2/3 of its peak value. Moreover, the blade pitch angle changes faster than increased by a regular control actuator. Copyright © 2009 John Wiley & Sons, Ltd.
A single dose of vitamin A improves haemoglobin concentration, retinol status and phagocytic function of neutrophils in preschool children
Authors: Jimenez Claudia , Leets Irene , Puche Rafael , Anzola Elsy , Montilla Rosa , Parra Cesar , Aguilera Antonia , García-Casal María N.
Published: December 2009

Since there is a reported interrelationship between vitamin A and Fe metabolism, and with immunological response, the objective was to evaluate the effect of a single dose of vitamin A administered to preschool children, on Fe and vitamin A nutritional status, anaemia and phagocytic function of neutrophils, 30 d after supplementation. A total of eighty children (sixty-eight supplemented and twelve controls) were supplemented orally with 200 000 IU (60 mg) vitamin A, and evaluated for nutritional, haematological and immunological responses at the beginning of the study and 30 d after supplementation. Parameters studied included Hb, serum ferritin, retinol and Fe concentrations, transferrin saturation, IL-4, interferon-γ and phagocityc capacity of neutrophils using non-fluorescent latex microbeads. After supplementation there was a significant increase in Hb concentration (P = 0·03), mean corpuscular Hb concentration (P = 0·001) and serum retinol (P = 0·0078). Prevalences of anaemia and vitamin A deficiency decreased significantly from 17·6 % to 13·2 % and from 25 % to 13·2 %, respectively. Regarding phagocytic function, there was a significant increase in the number of microbeads engulfed by neutrophils (P < 0·05) and no significant changes in cytokine concentrations at 1 month after treatment. A single dose of 200 000 IU (60 mg) vitamin A administered orally to a group of preschool children with a high prevalence of vitamin A deficiency enhanced serum retinol and Hb concentrations, decreased the prevalence of anaemia and vitamin A deficiency and improved the constitutive phagocytic capacity of neutrophils. Vitamin A supplementation could help to decrease vitamin A deficiency, anaemia prevalence and to improve the innate immunity response in preschool children. The effects were obtained without Fe supplementation.
Placenta: a possible predictor of vitamin A deficiency
Authors: Gomes Mirian Martins , Saunders Claudia , Ramalho Andrea
Published: December 2009

The objective of the present study is to assess the association between vitamin A deficiency (VAD) evaluated by serum retinol concentration from the mother and umbilical cord and placental concentration of retinol and carotenoids to propose placental values representative of deficiency. Two hundred and sixty-two puerperal women and their newborns were assessed. Concentration of serum and placental retinol and carotenoids was determined by the spectrophotometric method. Receiver operating characteristic (ROC) curve analysis was performed according to two cut-off points (0·70 and 1·05 μmol/l) to represent deficiency in the placental concentration. No difference between averages of placental retinol and carotenoids was observed in the puerperal women regardless of the cut-off point used to define VAD. In relation to the newborns, a decrease (P = 0·012) in placental retinol averages in individuals with VAD was observed when the 1·05 μmol/l cut-off point was adopted. In respect to the placental carotenoid averages, a decrease is observed for both the cut-off points (P = 0·013 and 0·019 for 1·05 and 0·7 μmol/l, respectively). The ROC curve results point to the value of 0·80 μmol/l as representing deficiency with greater values found for sensitivity (66·7 %), specificity (41·7 %) and accuracy (65 %) when the 0·70 μmol/l cut-off point was adopted. The results of the present study show an association between the placental concentration of retinol and carotenoids with clinical VAD, suggesting the need for further studies on more severe cases of deficiency.