bluuebunny/crossref_metadata_2025 huggingface dataset:
The rheology of aramid platelet suspensions
Authors: Liang Ruifeng , Han Long , Doraiswamy Deepak , Gupta Rakesh K.
Published: July 2011

The flow responses of aramid platelets (fibrids) suspended in a mixture of corn syrup and water at loadings of less than 1% were determined in steady shear, oscillatory shear, transient shear, and extensional flow. The effects of fibrid size, concentration, and suspending medium viscosity were examined. These suspensions exhibit a high zero‐shear viscosity, strong shear thinning with power law indices as low as 0.2, an infinite shear viscosity, and thixotropy. Steady shear viscosity data over six decades of shear rate were described very well by traditional models such as the Carreau or Cross equations. The platelets appear to form an interacting, flocculated network at rest that is the reason for the large relative viscosity. The largest platelets, however, appear to curl or fold and offer the least flow resistance during shear flow. The structure formed at rest is easily destroyed, and this is the reason for the observed shear thinning. In extensional flow, large Trouton ratios are observed even at very low fibrid concentrations, and these increase with the true aspect ratio, indicating that the fibrids are fully unfurled in the strongly orienting extensional flow. These rheological properties make fibrid suspensions good candidates for thickeners in sealant, caulk, and adhesive applications. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Layer‐by‐layer assembled polyelectrolyte blend membranes and their use for ion separation and rejection
Authors: Hoffmann Kristina , Friedrich Tatjana , Tieke Bernd
Published: July 2011

Polyelectrolyte blend films and membranes were prepared upon alternating electrostatic adsorption of polyallylamine hydrochloride (PAH) and mixtures of polystyrene sulfonate (PSS) and polyacrylic acid (PAA) in different ratio on solid supports. Infrared studies indicated that the PSS‐PAA blend composition of the films always differed from the mixture composition in the dipping solution, PSS being preferentially adsorbed. Films deposited on porous supporting membranes (polyacrylonitrile/polyethylene terephthalate) were studied on their ion permeation under diffusion dialysis conditions, and their flux and salt rejection under nanofiltration and reverse osmosis (RO) conditions. Blend membranes prepared at pH 1.7 exhibit a significantly improved anion separation and salt rejection, the ideal separation factor α(NaCl/Na2SO4) of a membrane prepared from a PSS:PAA mixture of 1:1 (w/w) being 197 ± 10 (pure PAH/PSS: 45). The NaCl and Na2SO4 rejections under RO conditions are 85 and 97% (pure PAH/PSS: 15 and 27%), respectively. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Magnesium hydroxide modified by 1‐n‐tetradecyl‐3‐carboxymethyl imidazolium chloride and its effects on the properties of LLDPE
Authors: Ding Yunsheng , Wang Ping , Wang Zhongli , Chen Long , Xu Hongmei , Chen Shengli
Published: July 2011

In this study, Mg(OH)2 (MH) was first modified by 1‐n‐tetradecyl‐3‐carboxymethyl imidazolium chloride ([C14cim]Cl), an imidazolium ionic liquid, and then the modified MH ([C14cim]Cl‐MH) was incorporated into linear low‐density polyethylene (LLDPE) by melt‐mixing to obtain the LLDPE/[C14cim]Cl‐MH composites. The interaction between [C14cim]Cl and MH was investigated by Fourier transform infrared spectroscopy (FT‐IR). The thermal decompostion behaviors of the LLDPE/[C14cim]Cl‐MH composites were characterized by thermogravimetric analysis (TGA). The flame retardance, tensile and Izod Impact properties of the LLDPE/[C14cim]Cl‐MH composites were tested. For comparison, the LLDPE/MH composites and LLDPE/SA‐MH composites (SA‐MH is stearic acid) were prepared and their properties were studied in the same way. It was found that [C14cim]Cl interacted with MH via chemical bonding, and served as an efficient lubricant and compatibilizer for MH and LLDPE, leading to great improvements of processability and mechanical properties of the LLDPE/[C14cim]Cl‐MH composites. The LLDPE/[C14cim]Cl‐MH composites also showed a remarkably promoted char formation and effectively eliminated melt drips, thus endowing the composites with sufficiently high flame retardancy. POLYM. ENG. SCI., © 2011 Society of Plastics Engineers
Macroscopic Approach to Plasma Polymerization Using the Concept of Energy Density
Authors: Hegemann Dirk , Schütz Urs , Körner Enrico
Published: July 2011

The film growth and the properties of plasma polymers are determined by gas phase and surface reactions. In order to gain more insights and to optimize plasma polymerization processes, some assumptions can be made that allow a macroscopic approach. Therefore, a concept was developed based on the energy input both into the gas phase (plasma) and during film growth (surface) that helps to distinguish between predominating gas phase or surface processes. Different experimental series using gas mixtures of C2H4 with CO2 or N2/H2 were performed at different power inputs W and gas flow rates F. Thereby, the same range of specific energy input W/F can be maintained at different ion bombardment to the substrate. The results indicate that changes in film growth were initiated by plasma chemical processes for CO2/C2H4 discharges (scavenger effects), while the obtained drop in deposition rate at high energy input values for N2/H2/C2H4 is caused by the energy dissipated in the film during growth pointing towards a threshold energy for chemical sputtering.

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Highly ordered three‐dimensional ZnO nanorods for novel photonic devices
Authors: Szabó Zoltán , Erdélyi Róbert , Makai János , Balázs János , Volk János
Published: July 2011

On‐purpose positioned epitaxial ZnO nanorods were grown on transparent substrate by wet chemical method. The high degree of vertical alignment can be ascribed to the epitaxial ZnO seed film deposited on a c‐plane sapphire substrate. The diffraction pattern taken on the array reveals the two‐dimensional ordering of the nanorods while the transmittance measurement showed high transparency. Both optical measurements were compared with three‐dimensional finite‐difference time‐domain simulations. The realized model structure promises novel applications such as three‐dimensional solar cells and photodetectors. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
From metal/semiconductor separation to single‐chirality separation of single‐wall carbon nanotubes using gel
Authors: Tanaka Takeshi , Liu Huaping , Fujii Shunjiro , Kataura Hiromichi
Published: July 2011

In the present work, a review of the metallic (M) and semiconducting (S) separation of single‐wall carbon nanotubes (SWCNTs) using polysaccharide gels is presented. First, the progress of the M/S separation is described, including the following: the discovery of high‐yield separation using agarose gel electrophoresis, the separation of SWCNTs without an electric field, such as through the use of the freeze and squeeze method, the development of continuous separation using column chromatography, and the single‐chirality separation of SWCNTs using a multicolumn with dextran‐based gel. Next, the separation mechanism using gel is discussed, in which separation is achieved by selective adsorption of S‐SWCNTs by gel with a specific combination of surfactant and gel. Lastly, future directions for the separation of SWCNTs and for the use of the separated SWCNTs are discussed.

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(© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synchrotron fluorescence nanoimaging of a single Co‐implanted ZnO nanowire
Authors: Chu M. H. , Segura‐Ruiz J. , Martinez‐Criado G. , Cloetens P. , Snigireva I. , Geburt S. , Ronning C.
Published: July 2011

In this study, we report the application of synchrotron radiation nanoprobe technique to the elemental analysis of single as‐grown and Co‐implanted ZnO nanowires. The nano‐X‐ray fluorescence technique enabled us not only to examine the spatial variation of Zn and Co elements, but also to disregard the presence of residual impurities in the nanowires, as well as the detection of Fe and Sn residual impurities in the substrates. Our observations provide strong evidence for the overall elemental uniformity of Zn and Co along the wires, without clustering or segregation effects. Within the nanoprobe spatial resolution, our findings indicate a Co localization within thicker irregularities observed with scanning electron microscopy. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Protective Effects of Aucubin on H2O2‐Induced Apoptosis in PC12 Cells
Authors: Xue Hong‐Yu , Gao Gui‐Zhen , Lin Qiu‐Ye , Jin Li‐Ji , Xu Yong‐Ping
Published: July 2011

The present study investigated the neuroprotective effects of aucubin on hydrogen peroxide (H2O2)‐induced apoptosis in PC12 cells. Exposure of PC12 cells to 0.25 mm H2O2 induced a leakage of lactate dehydrogenase and decreased cell viability, as shown by 3‐(4, 5‐dimethylthiazol‐2‐yl)‐2, 5‐diphenyltetrazolium bromide assay. In a dose over 0.1 mm, aucubin increased PC12 cellular viability and markedly attenuated H2O2‐induced apoptotic cell death. Quantitation of apoptosis by flow cytometry indicated that aucubin inhibited H2O2‐induced apoptosis in PC12 cells. Nuclear damage was alleviated by aucubin, as shown by Hoechst staining. In addition, the levels of malondialdehyde were reduced and the activity of superoxide dismutase, catalase and glutathione peroxidase was augmented in these cells. These results indicated that aucubin inhibited H2O2‐induced apoptosis in PC12 cells through regulation of the endogenous oxidant–antioxidant balance. Our results suggest that aucubin is a potential protective agent for the treatment of oxidative‐stress‐induced neurodegenerative disease. Copyright © 2011 John Wiley & Sons, Ltd.
Internal gravity waves convectively forced in the atmospheric residual layer during the morning transition
Authors: Gibert Fabien , Arnault Nicolas , Cuesta Juan , Plougonven Riwal , Flamant Pierre H.
Published: July 2011

Generation of internal gravity waves in the boundary layer is investigated from observations. Simultaneous measurements from a 2 µm Doppler lidar and a 0.5 µm backscatter lidar are combined to analyse the occurrence, or not, of internal gravity waves in the residual layer during the morning transition on two days, 10 and 14 June 2005. Three cases are studied for illustrating three different flow configurations in the residual layer: no wave, evanescent wave and propagating wave. Comparison of the three cases suggests two necessary conditions for the generation of gravity waves: a stably stratified residual layer and a convective boundary layer with mechanical forcing frequencies less than the Brunt–Vaïsala frequency. The horizontal wind shear probably plays a role in the dynamics of the waves, but, in the cases analysed, it is not sufficient alone to generate the observed waves through the obstacle effect. In the case of wave propagation, the waves tilt upstream and against the wind shear, with a typical horizontal wavelength and a line phase direction with respect to the vertical of 2.4 km and 32°, respectively. Unexpectedly, we found that measurements of the wave‐associated vertical velocity and the displacement of tracers (0.5 µm depolarization ratio or 2 µm backcatter, both indicative of relative humidity fluctuations) are in phase. Possible explanations include: (i) aerosol particles are not passive with respect to temperature or water vapour fluctuations; or (ii) a nonlinear wave‐turbulence interaction is at work and needs further investigation. Copyright © 2011 Royal Meteorological Society
A climatological study of polar lows in the Nordic Seas
Authors: Noer Gunnar , Saetra Øyvind , Lien Trond , Gusdal Yvonne
Published: July 2011

The climatology of polar lows over the Nordic Seas has been investigated using infrared satellite images for the period between 2000 and 2009. The same region was studied in the 1980s using traditional weather charts for the period between 1972 and 1982. One motivation for the present study was to revisit this climatology, but using a different decade and taking advantage of the vastly improved coverage and dissemination of infrared satellite images since the 1980s. The fact that forecasters at the Norwegian Meteorological Institute had introduced a routine to register polar‐low events systematically from 2000 and onward also provided a unique opportunity for extending the existing repository of subjectively identified polar‐low observations. On average we found 12 polar‐low events per year in the region of study. This is more than the earlier investigation, but we believe that this can be explained by the fact that the previous study relied almost uniquely on weather charts with very little information from ocean areas in the Nordic Seas. The largest numbers were found in January with an average of 2.8 polar‐low events per year. The study reconfirms the February minimum found in previous studies, but on the basis of our data we could not show that this minimum is statistically significant. It is suggested that this may be explained as a manifestation of the coldest winter month, when a surface‐pressure high over the Scandinavian mainland is common and the large‐scale atmospheric flow is less favourable to polar‐low formation. This hypothesis was tested by calculating the mean sea‐level pressure (MSLP) anomaly for January, February and March from an atmospheric reanalysis. This revealed a positive anomaly over Scandinavia and northwest Russia not found in the pressure distributions for January and March. Copyright © 2011 Royal Meteorological Society
The role of horizontal resolution for polar low simulations
Authors: McInnes Harold , Kristiansen Jørn , Kristjánsson Jón Egill , Schyberg Harald
Published: July 2011

Polar lows are intense mesoscale cyclones that mainly occur during the winter over the sea in polar regions. Owing to their small spatial scale with a diameter between 200 and 1000 km, simulating polar lows is a challenging task. In this study we investigated how increased resolution of a numerical weather prediction model impacts its ability to simulate polar lows. We focused on a polar low that was successfully captured by three different flights during the IPY‐THORPEX field campaign in 2008. Verifying model results against campaign data showed that decreasing the horizontal grid spacing from 12 to 4 km significantly improved the simulation of the developing polar low, and a further decrease to 1 km gave further improvement. A model run with latent heating reduced to 10% indicated an extensive influence of diabatic heating in this polar low case, and we suggest that the improved model performance at higher resolution could be connected to the model's handling of convection. Additional simulations starting 24 h later showed that the initial conditions were important for the model performance, and when simulating another polar low case we found that the model failed to produce the polar low independent of the resolution. This shows that while higher resolution indeed may give improved predictions of polar lows, other factors like synoptic situation, lateral boundaries and the initial condition may also be important. Copyright © 2011 Royal Meteorological Society
Application study of medical robots in vascular intervention
Authors: Lu Wang‐sheng , Xu Wu‐yi , Zhang Jing , Liu Da , Wang Da‐min , Jia Po , Li Zhi‐cao , Wang Tian‐miao , Zhang Da‐peng , Tian Zeng‐min , Zeng Yanjun
Published: July 2011

Background

Based on the background of minimally invasive surgery and applications of medical robots, a vascular interventional robotic system has been developed that can be used in the field of vascular intervention.

Methods

The robotic system comprises a propulsion system, an image navigation system and a virtual surgery training system. Integration of the three systems constitutes a vascular intervention prototype robotic system used to carry out in vitro vascular intervention and animal experiments.

Results

On a transparent glass vascular model, a catheter was shown to enter an arbitrary branch of the vascular model with catheter motion meeting the requirements of clinical vascular intervention surgery (VIS); i.e. error band of catheter motion < 0.5 mm. In the animal experiments, 1.33–2.00 mm (4F–6F) diameter catheters were selectively inserted successfully into predefined targets in the animal, such as the renal, cardiovascular and cerebrovascular artery. Compared with conventional manual surgery, the time for robotic surgery is a little longer. There were no operative complications in the animal experiments.

Conclusions

These simulation and animal study results demonstrate that this vascular interventional robotic system allows doctors to perform angiography remotely and prevents them from radiation exposure. The system may be the basis for further clinical applications of vascular intervention. Copyright © 2011 John Wiley & Sons, Ltd.
Scanning electron microscopy of Streptomyces without use of any chemical fixatives
Authors: Kumar Vijay , Bharti Alpana , Gusain Omprakash , Bisht Gajraj Singh
Published: July 2011

A new, short, and quick method was developed for preparation of specimen for observing Actinomycetes of genus Streptomyces by scanning electron microscopy. The cultures were directly grown on stubs and coated with a film of gold without using any fixative and dehydrating procedures. Using this simple preparation procedure, surface of intact sporing structures of Streptomyces was observed over a range of magnifications. As the preparation procedure is so simple and rapid, this procedure could be most useful for the routine examination and identification of Streptomyces. SCANNING 33:446–449, 2011. © 2011 Wiley Periodicals, Inc.
Mixed treatment comparison of repeated measurements of a continuous endpoint: an example using topical treatments for primary open‐angle glaucoma and ocular hypertension
Authors: Dakin Helen A. , Welton Nicky J. , Ades A.E. , Collins Sarah , Orme Michelle , Kelly Steven
Published: July 2011

Mixed treatment comparison (MTC) meta‐analyses estimate relative treatment effects from networks of evidence while preserving randomisation. We extend the MTC framework to allow for repeated measurements of a continuous endpoint that varies over time. We used, as a case study, a systematic review and meta‐analysis of intraocular pressure (IOP) measurements from randomised controlled trials evaluating topical ocular hypotensives in primary open‐angle glaucoma or ocular hypertension because IOP varies over the day and over the treatment course, and repeated measurements are frequently reported. We adopted models for conducting MTC in WinBUGS (The BUGS Project, Cambridge, UK) to allow for repeated IOP measurements and to impute missing standard deviations of the raw data using the predictive distribution from observations with standard deviations. A flexible model with an unconstrained baseline for IOP variations over time and time‐invariant random treatment effects fitted the data well. We also adopted repeated measures models to allow for class effects; assuming treatment effects to be exchangeable within classes slightly improved model fit but could bias estimated treatment effects if exchangeability assumptions were not valid. We enabled all timepoints to be included in the analysis, allowing for repeated measures to increase precision around treatment effects and avoid bias associated with selecting timepoints for meta‐analysis.The methods we developed for modelling repeated measures and allowing for missing data may be adapted for use in other MTC meta‐analyses. Copyright © 2011 John Wiley & Sons, Ltd.
Social comparison among competing firms
Authors: Kim Kwang‐Ho , Tsai Wenpin
Published: July 2011

Extending social comparison theory to the context of interfirm competition, we investigate whether and under what conditions firms may benefit by deviating from consumers' views concerning firm comparisons. Based on all of the possible dyadic competitive comparisons among the 26 automakers in the United States, we found that: (1) a focal firm enjoys a greater increase in sales than the target firm when it compares itself with a more reputable target firm, even though consumers do not perceive the focal firm to be comparable to the more reputable firm; and (2) a focal firm enjoys a greater increase in sales than the target firm when it avoids comparison with a less reputable target firm, even though consumers compare the focal firm with the less reputable firm. Copyright © 2011 John Wiley & Sons, Ltd.
Measuring the effect of M&A on patenting quantity and quality
Authors: Valentini Giovanni
Published: July 2011

I explore the effect of M&A on the patenting quantity and quality of the firms involved in a deal. Three measures of quality are considered: impact, generality, and originality. The impact of a patent denotes its influence on future inventions. Generality refers to a patent's applicability across technological fields. Finally, the originality of a patent indicates the extent to which an invention synthesizes diverse technological inputs. Applying a matching estimator to data from the U.S. ‘medical devices and photographic equipment’ industry from 1988 to 1996, I find that M&A have a positive effect on patenting output, but decrease patent impact, originality, and generality. Copyright © 2011 John Wiley & Sons, Ltd.
Does complexity deter customer‐focus?
Authors: Ethiraj Sendil K , Ramasubbu Narayan , Krishnan M.S.
Published: July 2011

Economic models suggest that firms use a simple cost‐benefit calculation to evaluate customer requests for new product features, but an extensive organizational literature shows the decision to implement innovation is more nuanced. We address this theoretical tension by studying how firms respond to customer requests for incremental product innovations, and how these responses change when the requested innovation is complex. Using large sample empirical analyses combined with detailed qualitative data drawn from interviews, we find considerable variance in the relationship between customer demands, complexity, and investments in incremental innovations. The qualitative study revealed the importance of organization structures, competitive pressures, and incentives for resource allocation processes. Copyright © 2011 John Wiley & Sons, Ltd.
A retrospective view of software maintenance and reengineering research – a selection of papers from European Conference on Software Maintenance and Reengineering 2010
Authors: Capilla Rafael , Dueñas Juan C. , Ferenc Rudolf
Published: July 2011

As a summary of past, current, and future trends in software maintenance and reengineering research, we give in this editorial a retrospective look from the past 14 years to now. We provide insight on how software maintenance has evolved and on the most important research topics presented in the series of the European Conference on Software Maintenance and Reengineering. Copyright © 2011 John Wiley & Sons, Ltd.
Educating Systems Thinking for Sustainability: Experience with a Developing Country
Authors: Nguyen Nam C. , Graham Doug , Ross Helen , Maani Kambiz , Bosch Ockie
Published: July 2011

This paper describes an approach to teaching systems thinking and associated capacity building for a team of professionals and managers from a developing country (Vietnam), engaged in the sustainable management of a world biosphere reserve. Vietnamese environmental and development managers and UNESCO were attracted to a systems approach to managing the Cat Ba Biosphere Reserve because it offered a way to address components of sustainability holistically, while transcending organisational and disciplinary ‘silos’. Key features of the training approach include learning as a group of professionals, with senior organisational support and commitment to apply systems approaches in the workplace; enjoyable adult learning approaches tailored to the needs of participants; complementing teaching of systems thinking and techniques with participatory methods for working with the participants in developing solutions to their sustainability issues; and building in evaluation at every stage, through participatory methods taught in the course. The paper highlights the importance of teaching systems thinking and provides an example curriculum and teaching strategy based on adult learning principles. Copyright © 2011 John Wiley & Sons, Ltd.
Neural Stem Cells Maintain Their Stemness through Protein Kinase C ζ-Mediated Inhibition of TRIM32
Authors: Hillje Anna-Lena , Worlitzer Maik M. A. , Palm Thomas , Schwamborn Jens C.
Published: July 2011

Several studies over the last couple of years have delivered insights into the mechanisms that drive neuronal differentiation. However, the mechanisms that ensure the maintenance of stemness characteristics in neural stem cells over several rounds of cell divisions are still largely unknown. Here, we provide evidence that the neuronal fate determinant TRIM32 binds to the protein kinase C ζ. Through this interaction, TRIM32 is retained in the cytoplasm. However, during differentiation, this interaction is abrogated and TRIM32 translocates to the nucleus to initiate neuronal differentiation by targeting c-Myc for proteasomal degradation.
Multi‐electron integrals
Authors: Reine Simen , Helgaker Trygve , Lindh Roland
Published: July 2011

This review presents techniques for the computation of multi‐electron integrals over Cartesian and solid‐harmonic Gaussian‐type orbitals as used in standard electronic‐structure investigations. The review goes through the basics for one‐ and two‐electron integrals, discuss details of various two‐electron integral evaluation schemes, approximative methods, techniques to compute multi‐electron integrals for explicitly correlated methods, and property integrals. © 2011 John Wiley & Sons, Ltd.

This article is categorized under:

Electronic Structure Theory > Ab Initio Electronic Structure Methods
Mechanisms of branch formation in metal‐catalyzed ethene polymerization
Authors: Budzelaar Peter H. M.
Published: July 2011

Branches are an important aspect of the structure of real polyethylene. Branches can be short (Me, Et) or longer; long‐chain branches (LCB, >100 carbons), in particular, are important because they can have a dramatic effect on polymer properties. In this review, we summarize mechanistic information from organometallic and computational chemistry and use this to examine the most probable sources of each type of branch. Short branches can be introduced deliberately by copolymerization with an α‐olefin (possibly formed in situ from ethene). Me branches may be formed by one‐carbon chain walking and propagation, and/or from insertion of an oligomer/macromer in an MMe bond formed via chain transfer to the cocatalyst [Me3Al or methylaluminoxane (MAO)]. Et branches are most likely formed through β‐hydrogen transfer to ethene, followed immediately by reinsertion of the newly formed macromer. LCBs have usually been ascribed to reinsertion of macromers. However, certain catalysts exhibit LCB formation patterns that are hard to reconcile with this model, and a ‘two‐monomer’ model was recently proposed to explain the observations for these systems. In this review, we present an alternative explanation (chain walking) that would fit the same facts for these catalysts. © 2011 John Wiley & Sons, Ltd.

This article is categorized under:

Structure and Mechanism > Molecular Structures
Generalized self‐consistent like method for mechanical degradation of fibrous composites
Authors: Boso D.P. , Lefik M. , Schrefler B.A.
Published: July 2011

This paper deals with homogenization of heterogeneous, fibre‐reinforced material. One of the main points of the work consists in taking into account the breakage of the fibres, to compute the effective behaviour of the damaged composite. Furthermore, the possible yielding of the matrix material is considered. The problem is solved for the coupled thermo‐mechanical field, that is all material characteristics can be temperature dependent and thermal loads can be simulated. The method is based on a self consistent type scheme, suitably extended for the case at hand. The effective behaviour is obtained by considering isotropic elastic‐brittle cylindrical inclusions surrounded by a shell of elasto‐plastic matrix material immersed in an infinite medium endowed with the effective properties. Usually in the framework of the self consistent scheme, the homogenised material behaviour is obtained with a symbolic approach. On the contrary, in this work the solution is found in a non‐classical way, as we use the finite element method to find the solution of the thermo‐mechanical problem as a function of the effective material characteristics.
Outcomes of Laparoscopic Versus Open Colectomy in Elective Surgery for Diverticulitis
Authors: Masoomi Hossein , Buchberg Brian , Nguyen Brian , Tung Vicrumdeep , Stamos Michael J. , Mills Steven
Published: July 2011

Background

The role of laparoscopy in the management of diverticular disease is evolving. Concerns were raised in the past because laparoscopic resection for diverticulitis is often difficult and occasionally hazardous. This study was undertaken to evaluate the difference in overall outcomes between elective open and laparoscopic surgery with or without anastomosis for diverticulitis.

Methods

Using the National Inpatient Sample (NIS) database, clinical data of patients who underwent elective open and laparoscopic surgery (lap) for diverticulitis from 2002 to 2007 were collected and analyzed. Patients who underwent emergent surgery were excluded.

Results

A total of 124,734 patients underwent elective surgery for diverticulitis: open, 110,172 (88.3%); lap, 14,562 (11.7%). The overall intraoperative complication rate was significantly lower in the laparoscopy group (0.63% vs. 1.15%, P < 0.01). However, there was no significant difference observed in ureteral injury between groups (open, 0.17%; lap, 0.12%, P = 0.15). All evaluated postoperative complications (ileus, abdominal abscess, leak, wound infection, bowel obstruction, urinary tract infection, pneumonia, respiratory failure, venous thromboembolism) were significantly higher for the open procedures. The laparoscopy group had a shorter mean hospital stay (lap, 5.06 days; open, 6.68 days, P < 0.01) and lower total hospital charges (lap, $36,389; open, $39,406, P < 0.01) than the open group. Also, mortality was four times higher in the open group (open, 0.54%; lap, 0.13%, P < 0.01).

Conclusions

The laparoscopic operation was associated with lower morbidity, lower mortality, shorter hospital stay, and lower hospital charges compared to the open operation for diverticulitis. Elective laparoscopic surgery for diverticulitis is safe and can be considered the preferred operative option.
Isolation of a Novel Oil Globule Protein from the Green Alga Haematococcus pluvialis (Chlorophyceae)
Authors: Peled Ehud , Leu Stefan , Zarka Aliza , Weiss Meira , Pick Uri , Khozin‐Goldberg Inna , Boussiba Sammy
Published: July 2011

Cytoplasmic oil globules of Haematococcus pluvialis (Chlorophyceae) were isolated and analyzed for pigments, lipids and proteins. Astaxanthin appeared to be the only pigment deposited in the globules. Triacyglycerols were the main lipids (more than 90% of total fatty acids) in both the cell‐free extract and in the oil globules. Lipid profile analysis of the oil globules showed that relative to the cell‐free extract, they were enriched with extraplastidial lipids. A fatty acids profile revealed that the major fatty acids in the isolated globules were oleic acid (18:1) and linoleic acid (18:2). Protein extracts from the globules revealed seven enriched protein bands, all of which were possible globule‐associated proteins. A major 33‐kDa globule protein was partially sequenced by MS/MS analysis, and degenerate DNA primers were prepared and utilized to clone its encoding gene from cDNA extracted from cells grown in a nitrogen depleted medium under high light. The sequence of this 275‐amino acid protein, termed the Haematococcus Oil Globule Protein (HOGP), revealed partial homology with a Chlamydomonas reinhardtii oil globule protein and with undefined proteins from other green algae. The HOGP transcript was barely detectable in vegetative cells, but its level increased by more than 100 fold within 12 h of exposure to nitrogen depletion/high light conditions, which induced oil accumulation. HOGP is the first oil‐globule‐associated protein to be identified in H. pluvialis, and it is a member of a novel gene family that may be unique to green microalgae.
Amadori‐Glycated Phosphatidylethanolamine, a Potential Marker for Hyperglycemia, in Streptozotocin‐Induced Diabetic Rats
Authors: Sookwong Phumon , Nakagawa Kiyotaka , Fujita Ikuko , Shoji Naoki , Miyazawa Teruo
Published: July 2011

It has been demonstrated in vivo that lipid glycation products such as Amadori‐glycated phosphatidylethanolamine (Amadori‐PE) accumulate in the plasma of diabetic humans and animals, but how lipid glycation products are formed under hyperglycemic conditions are not clear. We sought to clarify the occurrence of lipid glycation and its relationships with lipid peroxidation and protein glycation during the development of hyperglycemia using the streptozotocin (STZ)‐induced diabetic rat model. A significant increase in Amadori‐PE was observed in STZ rats 7 days after STZ treatment, and Amadori‐PE (especially 18:0–20:4 Amadori‐PE) was found at high levels in the blood and in organs that are strongly affected by diabetes, such as the kidney. Significant changes in Amadori‐PE appeared to occur prior to changes in levels of oxidized lipids, which increased after 21–28 days. In addition, accumulation of Nε‐(carboxymethyl)lysine (CML), a protein glycation product, proceeded somewhat more slowly and moderately than that of Amadori‐PE, suggesting that Amadori‐PE and CML are early and advanced glycation products, respectively. Our results suggest that Amadori‐PE may be a useful predictive marker for hyperglycemia, particularly in the early stages of diabetes. Similar speculations have been made from previous human studies, but this study provides a direct evidence to support the speculations in rat study.
FSH acts on the proliferation of type A spermatogonia via Nur77 that increases GDNF expression in the Sertoli cells
Authors: Ding Li-Jun , Yan Gui-Jun , Ge Qiu-Yan , Yu Fei , Zhao Xia , Diao Zhen-Yu , Wang Zhi-Qun , Yang Zhong-Zhou , Sun Hai-Xiang , Hu Ya-Li
Published: July 2011

The molecular mechanism responsible for the regulation of GDNF in Sertoli cells remains largely unknown. In the present study, FSH induced the expression of Nur77 and GDNF in mouse testis tissue and human fetal Sertoli cells. Moreover, FSH increased the number of A spermatogonia co‐cultured with Sertoli cells. In the additional assays, Nur77 was observed to directly regulate GDNF transcription. Furthermore, overexpression of Nur77 and siRNA‐mediated knockdown of Nur77 affected levels of GDNF mRNA and protein in primary human fetal Sertoli cells. These results indicate that FSH‐induced Nur77 regulates the expression of GDNF in Sertoli cells to stimulate the proliferation of A spermatogonia in vitro.
Biosynthesis and secretion of mouse cysteine‐rich with EGF‐like domains 2
Authors: Oh-hashi Kentaro , Kunieda Ryosuke , Hirata Yoko , Kiuchi Kazutoshi
Published: July 2011

In this study, we found that Cysteine‐rich with EGF‐like domains 2 (CRELD2), a novel endoplasmic reticulum stress‐inducible protein, is not only localized in the ER‐Golgi apparatus but also spontaneously secreted. Deletion of four C‐terminal amino acids from mouse CRELD2 or addition of tag‐peptides to its C‐terminus dramatically enhanced CRELD2 secretion. Intra‐ and extra‐cellular CRELD2 is differentially glycosylated and its spontaneous secretion was significantly prevented by overexpression of a dominant negative mutant Sar1 and treatment with brefeldin A. Overexpression of wild‐type GRP78 remarkably enhanced the secretion of wild‐type but not mutant CRELD2. Our results demonstrate both that CRELD2 is a novel secretory glycoprotein regulated by Sar1 and GRP78 and that the C‐terminal of CRELD2 plays a crucial role in its secretion.
A predictive inner–outer model for streamwise turbulence statistics in wall-bounded flows
Authors: MATHIS ROMAIN , HUTCHINS NICHOLAS , MARUSIC IVAN
Published: July 2011

A model is proposed with which the statistics of the fluctuating streamwise velocity in the inner region of wall-bounded turbulent flows are predicted from a measured large-scale velocity signature from an outer position in the logarithmic region of the flow. Results, including spectra and all moments up to sixth order, are shown and compared to experimental data for zero-pressure-gradient flows over a large range of Reynolds numbers. The model uses universal time-series and constants that were empirically determined from zero-pressure-gradient boundary layer data. In order to test the applicability of these for other flows, the model is also applied to channel, pipe and adverse-pressure-gradient flows. The results support the concept of a universal inner region that is modified through a modulation and superposition of the large-scale outer motions, which are specific to the geometry or imposed streamwise pressure gradient acting on the flow.
Adverse metabolic phenotype in low-birth-weight lambs and its modification by postnatal nutrition
Authors: Wallace Jacqueline M. , Milne John S. , Adam Clare L. , Aitken Raymond P.
Published: July 2011

Both high and low maternal dietary intakes adversely affect fetal nutrient supply in adolescent sheep pregnancies. Aims were: (a) to assess the impact of prenatal nutrition on pregnancy outcome, offspring growth and offspring glucose metabolism and (b) to determine whether the offspring metabolic phenotype could then be altered by modifying postnatal nutrition. Dams carrying a single fetus were offered either an optimal control (C) intake to maintain adiposity throughout pregnancy, undernourished to maintain weight at conception but deplete maternal reserves (UN), or overnourished to promote rapid maternal growth and adiposity (ON). Placental weight and gestation length were reduced in ON dams and lamb birth weights were C>UN>ON (P < 0·001). All offspring were fed ad libitum from weaning to 6 months of age. ON offspring exhibited rapid catch-up growth and had increased fasting glucose and relative glucose intolerance compared with C offspring (P < 0·05). Irrespective of prenatal diet and sex, birth weight correlated negatively with these indices of glucose metabolism. From 7 to 12 months offspring either had continued ad libitum diet (ADLIB; to induce an obesogenic state) or a decreased ration appropriate for normal growth (NORM). At 12 months, the negative relationship between birth weight and indices of glucose metabolism persisted in ADLIB females (for example, fasting glucose, r − 0·632; P < 0·03) but was absent in NORM females and in both male groups. Therefore, low-birth-weight offspring from differentially achieved prenatal malnutrition exhibit an early adverse metabolic phenotype, and this can apparently be ameliorated by postnatal nutrition in females but not in males.
Zagros orogeny: a subduction-dominated process
Authors: AGARD P. , OMRANI J. , JOLIVET L. , WHITECHURCH H. , VRIELYNCK B. , SPAKMAN W. , MONIÉ P. , MEYER B. , WORTEL R.
Published: July 2011

This paper presents a synthetic view of the geodynamic evolution of the Zagros orogen within the frame of the Arabia–Eurasia collision. The Zagros orogen and the Iranian plateau preserve a record of the long-standing convergence history between Eurasia and Arabia across the Neo-Tethys, from subduction/obduction processes to present-day collision (from ~ 150 to 0 Ma). We herein combine the results obtained on several geodynamic issues, namely the location of the oceanic suture zone, the age of oceanic closure and collision, the magmatic and geochemical evolution of the Eurasian upper plate during convergence (as testified by the successive Sanandaj–Sirjan, Kermanshah and Urumieh–Dokhtar magmatic arcs), theP–T–thistory of the few Zagros blueschists, the convergence characteristics across the Neo-Tethys (kinematic velocities, tomographic constraints, subduction zones and obduction processes), together with a survey of recent results gathered by others. We provide lithospheric-scale reconstructions of the Zagros orogen from ~ 150 to 0 Ma across two SW–NE transects. The evolution of the Zagros orogen is also compared to those of the nearby Turkish and Himalayan orogens. In our geotectonic scenario for the Zagros convergence, we outline three main periods/regimes: (1) the Mid to Late Cretaceous (115–85 Ma) corresponds to a distinctive period of perturbation of subduction processes and interplate mechanical coupling marked by blueschist exhumation and upper-plate fragmentation, (2) the Paleocene–Eocene (60–40 Ma) witnesses slab break-off, major shifts in arc magmatism and distributed extension within the upper plate, and (3) from the Oligocene onwards (~ 30–0 Ma), collision develops with a progressive SW migration of deformation and topographic build-up (Sanandaj–Sirjan Zone: 20–15 Ma, High Zagros: ~12–8 Ma; Simply Folded Belt: 5–0 Ma) and with partial slab tear at depths (~10 Ma to present). Our reconstructions underline the key role played by subduction throughout the whole convergence history. We finally stress that such a long-lasting subduction system with changing boundary conditions also makes the Zagros orogen an ideal natural laboratory for subduction processes.
The Grading of Cultural Relics in Chinese Law
Authors: Lau Timothy
Published: July 2011

Legal systems which triage protection to cultural relics based on a relic grading system have been adopted by several countries. This article examines the implementation of such a relic grading framework by the People's Republic of China. The current state of the law is summarized, and a recent criminal trial is described to illustrate the role the grading system plays within the law. The factors involved in defining the grades of cultural relics are then discussed in context of a cultural relic structural framework, with emphasis to both the state values that they serve and their ability to promote the objective of cultural property protection. The analysis highlights the problems and general considerations with the use of relic grading systems as a means to protect a large number of relics with finite resources.
Stepping Stones Across the Lihir Islands: Developing Cultural Heritage Management in the Context of a Gold-Mining Operation
Authors: Bainton Nicholas A. , Ballard Chris , Gillespie Kirsty , Hall Nicholas
Published: July 2011

Large-scale resource extraction projects often create obstacles for the protection, maintenance, and inheritance of indigenous cultural heritage. In this article we detail some of the challenges and opportunities arising from our collaborative partnership with the community of the Lihir Islands in Papua New Guinea, which is seeking to establish, inform, and resource a formal cultural heritage management program in the context of a large-scale gold-mining operation. The general approach to this collaborative venture involves the application of a specific development tool, the Stepping Stones for Cultural Heritage program. This consultative process is innovative in both Melanesia and the context of resource extraction, but also more generally within the field of cultural heritage. We describe the outcomes of this process and some of the initial pilot projects, one of which was based on the recording of traditional Lihirian songs. We also argue that while the mine places greater pressure upon Lihirian cultural heritage, it also presents Lihirians with the opportunity to realize a vision of their cultural future that is beyond the reach of many other indigenous communities.
Secrecy and the city, 1870–1939
Authors: Vincent David
Published: July 2011

This paper discusses the treatment of space and social interaction in the emerging modern city, and argues that the notion of ‘reserve’ developed by Georg Simmel blurs the key polarity between secrecy and privacy. Case histories of home visiting and gossip are used to examine how the boundaries between the two forms of blocked communication were constructed and negotiated in the late nineteenth and early twentiethcentury British city. There was no unilinear transition from open to closed personal contacts, but rather a series of conflicts and anxieties generated by issues of class and political authority. The contingent distinction between privacy and secrecy revolved around the question of trust, which was in turn a function of domestic and corporate prosperity.
Did politics matter? Municipal public health expenditure in the 1930s
Authors: Powell Martin
Published: July 2011

This paper examines the relatively neglected topic of municipal public health expenditure in the inter-war period, and emphasizes two neglected dimensions: the political and the geographical. After justifying the importance of the topic and the approach and giving some details of municipal public health provision, a quantitative analysis of expenditure in the urban county boroughs is presented. In general, the analysis tends to argue against conventional wisdom in stressing the political dimension instead of the economic dimension in explaining the pattern of expenditure, giving a positive answer to the question posed in the title.
Wrestling with the angel: on problems of definition in urban historiography
Authors: Jansen Harry S.J.
Published: July 2011

The question ‘what is the city’ raised by Martindale in his edition of Max Weber's The City is an omnipresent one in urban history. This analysis of urban historiography since 1840 explores two definitional strands, each with many theoretical dimensions. The first is a somewhat self-contained conception of the city and relies on rural-urban contrasts; the second is a more open conceptualization of the city. The article tries to unravel the different approaches rather than preferring one approach to the other
Becoming early modern in the late medieval Low Countries
Authors: Howell Martha , Boone Marc
Published: July 2011

The history of cities in the Low Countries at the end of Middle Ages is commonly presented as one of discontinuity in which old textile centres collapsed, and were replaced by new centres such as Antwerp, Leiden, Lille and Amsterdam which were in fundamental respects entirely unlike their medieval predecessors. This conventional interpretation is challenged with reference to Ghent and Douai. Neither suffered devastating economic decline, social trauma or political upheaval in the period, and both enjoyed a degree of relative economic success. Contradictions are also identified, especially the way that economic flexibility was associated with an intensification of social conservatism. This process not only helped produce a characteristically ‘early modern’ social order but also decisively linked the ‘medieval’ with the ‘early modern’ in these two cities.
The Hair Follicle Bulge: A Niche for Adult Stem Cells
Authors: Pasolli Hilda Amalia
Published: July 2011

Adult stem cells (SCs) are essential for tissue homeostasis and wound repair. They have the ability to both self-renew and differentiate into multiple cell types. They often reside in specialized microenvironments or niches that preserve their proliferative and tissue regenerative capacity. The murine hair follicle (HF) has a specialized and permanent compartment—the bulge, which safely lodges SCs and provides the necessary molecular cues to regulate their function. The HF undergoes cyclic periods of destruction, regeneration, and rest, making it an excellent system to study SC biology.