bluuebunny/crossref_metadata_2025 huggingface dataset:
Inter‐industry Technology Spillover Effects in China: Evidence from 35 Industrial Sectors
Authors: Pan Wenqing , Yang Delin , Lin Min
Published: April 2012

The present paper calculates 35 industrial sectors' similarity matrices for the period of 1997–2008 using China's input–output tables for 1997, 2002 and 2007, and uses these to measure inter‐industry technology spillover to analyze the spillover effects on industrial sectors' labor productivity. The empirical analysis shows that inter‐industry technology spillover has a significant positive effect on the labor productivity of each industry. The elasticity of productivity effects of inter‐industry technology spillover is not only larger than that of direct R&D input, but also increases over time. We group the industries into four major categories and find that the inter‐industry technology spillover effect within the categories is, on average, greater than that between the four categories, indicating that technology spillover occurs more easily between similar industries. This research shows that the interindustry technology spillover effect in China has begun to increase, and the government should take advantage of this effect.
Light chain deposition disease: novel biological insights and treatment advances
Authors: JIMENEZ‐ZEPEDA V. H.
Published: April 2012

Light chain deposition disease (LCDD) is a monoclonal gammopathy characterized by nonamyloid deposition of immunoglobulin light chains in various organs. Most cases present with renal dysfunction, a ubiquitous feature of this disease, and in some instances, it may progress to end‐stage renal disease. Unfortunately, until now, no standard treatment has been established. The use of alkylating agents and steroids has been extensively reported. However, conventional chemotherapy response is generally limited with minor effects on kidney function. The use of novel agents such as bortezomib has shown a more rapid response with a dramatically important reduction of light chains in serum and/or urine in small series of cases. Furthermore, autologous stem cell transplantation has been reported as a feasible strategy in LCDD, able to prolong the dialysis‐free survival. Nonetheless, toxicity from these therapies should be considered carefully because most of patients might present with kidney dysfunction that could limit the use of some agents.
Grazing management in saltmarsh ecosystems drives invertebrate diversity, abundance and functional group structure
Authors: FORD HILARY , GARBUTT ANGUS , JONES LAURENCE , JONES DAVEY L.
Published: April 2012

Abstract.  1. Saltmarsh conservation management often involves livestock grazing to maximise plant diversity and provide suitable breeding habitat for over‐wintering coastal birds. The effect of grazing on invertebrates is rarely quantified, but results from limited studies of terrestrial and coastal grasslands demonstrate greater abundance and species richness in un‐grazed grassland.

2. The impact of short sward (<8 cm) cattle grazing on the ground dwelling invertebrate community was assessed on an English inter‐tidal upper salt marsh using pitfall traps. Abundance, species richness, functional group structure, abundance of coastal specialists, environmental factors that influence invertebrate habitat choice and food web composition were compared for grazed and un‐grazed marsh.

3. In total, 90 000 invertebrates were sampled. Predatory, zoophagus and detritivorous Coleoptera were significantly more abundant on the un‐grazed marsh. In contrast, predatory Hemiptera and Araneae were significantly more abundant on the grazed marsh. Sheet weaver spiders were significantly more abundant on the grazed marsh, foliage running hunters and space web builders more abundant on the un‐grazed marsh. Most inter‐tidal coastal specialist species exhibited clear habitat preference for the grazed marsh. Total species richness was not significantly different between grazing treatments.

4. Linear direct gradient analysis showed that two environmental variables influenced by grazing intensity, soil temperature and vegetation height, significantly explained the composition of invertebrate functional groups. Larger bodied invertebrates dominated the un‐grazed food web.

5. We conclude that both short sward cattle grazed and un‐grazed saltmarsh habitat should be maintained to maximise invertebrate abundance and diversity and provide suitable habitat for coastal specialists.
Comparison of the feasibility of three flood‐risk extent delineation techniques using Geographic Information System: case study in Tavoliere delle Puglie, Italy
Authors: Strobl R.O. , Forte F. , Lonigro T.
Published: April 2012

Delineation of flood‐risk extent is a tedious task which normally requires the expertise of trained hydrologists. In order to provide a quicker and more automated approach for estimating flood‐risk extent, three straightforward methods (Mahalanobis distance, Maximin and Equally likely decision methods) which are easily executed in Geographic Information System were investigated and applied to a study area in the so‐called ‘Tavoliere delle Puglie’ (southern Italy). The delineated areas were then visually and statistically confronted with a methodology based on hydrologic expertise that can be considered up to date with current flood‐risk zone delineation knowledge. Two major problems associated with flood‐risk extent estimation are firstly the overwhelming complexity of the wide variety of spatially relevant flood‐related data and the amount of information contained within these data that are not easily interpreted without often costly and time consuming hydrologic expertise, and secondly, the wide variety of criteria usually considered in flood‐risk analysis, yielding a broad spectrum of different units involved. The comparative analysis has revealed that of the three alternative methods, only the Mahalanobis distance technique gave moderately comparable results with the methodology based on hydrologic expert knowledge. The results suggest and confirm that hydrologic expertise cannot be bypassed in flood‐risk extent analysis.
Cost of Equity and S&P 500 Index Revisions
Authors: Baran Lindsay , Dolly King Tao‐Hsien
Published: April 2012

We examine how the cost of equity changes when firms are added to or removed from the S&P 500 Index during index revisions. Newly added firms experience a significant decline in the cost of equity, while recently removed firms show a significant increase. Liquidity improves for addition firms and declines for removed firms. Addition firms also experience a decline in shadow cost. Changes in cost of equity for included firms are explained by changes in liquidity, shadow cost, and firm size. Finally, included firms with greater investment opportunities benefit more from the reduction in cost of capital.
Novel Treatment for Osteonecrosis of the Humeral Head Using the Trufit Plug: A Synthetic Bone-Graft Substitute
Authors: Alexander Susan , Mcbirnie Julie M.
Published: April 2012

Treatment of avascular necrosis of the humeral head is a challenging clinical problem because patients often present at a young age with established destruction of bony tissue. Reccommended surgical treatment at this stage of the disease is joint replacement surgery using a metal implant, although this has potential complications. The present case report describes the novel use of a synthetic bone-graft substitute (TruFit plug; Smith & Nephew, Andover, MA, USA) that was successfully used to restore full range of movement and completely alleviate pain in a patient with stage II avascular necrosis of the right humeral head.
Phylogeographic analyses of Phragmites australis in China: Native distribution and habitat preference of the haplotype that invaded North America
Authors: AN Jia‐Xing , WANG Qian , YANG Ji , LIU Jian‐Quan
Published: April 2012

Abstract  Phragmites australis is a cosmopolitan clonal species, but one haplotype from Eurasia has become highly invasive in North America. This article describes an investigation of the phylogeographic composition of 77 populations from China, based on the sequencing of two chloroplast non‐coding DNA regions. A total of 11 haplotypes were detected, based on the sequence alignments of two chloroplast DNA fragments from 421 sampled individuals. Six of these haplotypes were completely new, and did not correspond to any of this species’ 27 previously known haplotypes. The invasive haplotype M and haplotypes O and P were shown to occur frequently. Haplotype O is widely distributed across all regions and probably represents the primitive haplotype of this species. In contrast, P is mainly distributed in the humid eastern and northeastern regions of China, whereas M is more frequent in western and northwestern China—arid habitats with low precipitation. Between eastern and northeastern and western and northwestern regions, there was distinct genetic differentiation; the former region has a higher genetic diversity than the latter. The high occurrence of haplotype M in western China suggests that it prefers more arid habitats. These findings shed new light on the native distribution, adaptation, and habitat preference of haplotype M, which invaded North America.
Treatment extension may benefit female genotype 1 chronic hepatitis C patients with complete early virological response to peginterferon‐alpha‐2b and ribavirin combination therapy
Authors: Nishimura Takeshi , Yamaguchi Kanji , Hashimoto Hiroaki , Niimi Toshihisa , Yokomizo Chihiro , Fujii Hideki , Minami Masahito , Sakamoto Masafumi , Ohnish Naoki , Nagao Yasuyuki , Okita Mika , Umemura Atsushi , Shima Toshihide , Okanoue Takeshi , Itoh Yoshito
Published: April 2012

Aim:  Little is known about the appropriate use of peginterferon‐α‐2b (PEG IFN‐α‐2b) or ribavirin (RBV) in genotype 1 chronic hepatitis C (CH‐C) patients with complete early virological response (cEVR). Female patients, especially the older, are known to experience inferior treatment outcomes.

Method:  A total of 150 CH‐C patients with cEVR treated for 48 weeks (n = 104) or 52–64 weeks (n = 46) with PEG IFN‐α‐2b and RBV combination therapy were retrospectively analyzed to evaluate the benefits of extended treatment.

Results:  In the 48‐week group, patients without a sustained virological response (SVR) were more often female (P = 0.004) and had received a significantly lower total RBV dose (P = 0.003) than those with SVR. The SVR rate in these female patients was similar to males with hepatitis C virus (HCV) RNA negativity at treatment week 8 (P = 0.413); however, it was lower than that in males with HCV RNA negativity at treatment week 12 (P = 0.005). In the 52–64‐week group, although the total RBV dose (mg/kg) after treatment week 48 was less in females than in males (P = 0.027), the SVR rate in females was equivalent to that in males (P = 0.604).

Conclusion:  Genotype 1 CH‐C patients treated with PEG IFN‐α‐2b and RBV combination therapy without SVR were more often female and had received a lower total RBV dose than males. The smaller SVR rate in female patients with cEVR compared to males may be overcome by extending treatment even if the RBV dose is lowered due to anemia.
Concurrent use of complementary and alternative medicine with antiretroviral therapy reduces adherence to HIV medications
Authors: Ekwunife Obinna Ikechukwu , Oreh Chinekwu , Ubaka Chukwuemeka Micheal
Published: April 2012

Objective

Antiretroviral therapy requires strict adherence to ensure therapeutic success. Concurrent use of complementary and alternative medicine (CAM) could alter the adherence to and thereby effectiveness of antiretroviral drugs. This study examined the association of CAM use with adherence to antiretroviral therapy (ART) and CD4 count.

Methods

The study was conducted in two HIV clinics: one in a semi-urban, the other in a rural area. Adherence to ART was assessed using the Morisky Medication Adherence Scale (MMAS). Data on type of CAM used and MMAS adherence were collected by patient interview and demographic; clinical data were collected from hospital records.

Results

Altogether 212 HIV patients participated in the exit study conducted over 3 months. Almost half (47.9%) used CAM concurrently with antiretroviral drugs. Dietary supplements (40.3%), healing systems (36.5%) and exercise (23.2%) were mainly used. The use of CAM significantly lowered adherence to ART (89.4% in non-CAM users versus 82.5% in CAM users, P = 0.01). Improvement in CD4 count was less in patients using CAM compared to non-CAM users although the difference was not statistically significant (310.5 ± 294.0 cells/L in CAM users versus 224.5 ± 220.0 cells/L in non-CAM users, P = 0.13). Patients attending the rural HIV clinic were more likely to use CAM compared to patients attending semi-urban hospital (χ2 test = 7.0; P < 0.01).

Conclusion

Use of CAM could lower adherence to antiretroviral therapy. There is need to develop protocol which could help in monitoring CAM use in HIV patients especially those from rural settings.
“My Child is Your Child”: Family Behavior in a Mexican Science Museum
Authors: Briseño‐Garzón Adriana , Anderson David
Published: April 2012

Abstract  In this paper we describe the particularities of Latin American museum visitors as learners through an exploratory study that took place at Universum, Museo de las Ciencias, a science museum located in Mexico City. The exploration of the learning experiences of Latin American family groups was carried out by means of a case study approach and from a socio‐cultural theory perspective. This inquiry of 20 family groups reveals that nuances of the concept of “family,” in the Mexican context, are important in studying family learning in museum settings. The prominent roles of the extended family and interactions within family groups are discussed as intrinsic traits of a family’s museum learning. In addition, the outcomes of this study highlight the impact that the Latin American notion ofeducaciónhas on museum education and research, as it encompasses issues that relate to the perpetuation of socio‐cultural values, child‐rearing, and ultimately, cultural identity.
Chiming in on Museums and Participatory Culture
Authors: Stein Robert
Published: April 2012

Abstract   The deep trove of information available on the Internet and the expanding connections it affords to new communities online have been a transforming force in museums in the recent past. A single individual can publish thoughts and ideas to an audience of millions with a few simple clicks of a button. The cultural sector has made great strides in adopting these same methods to advance the missions and content of our organizations; however, a rise in participatory culture poses a number of challenges for the role of museums and our place in the evolving culture of our community. A debate surrounding the changing nature of authority and the participatory expectations of society is central to defining how museums can meaningfully engage with contemporary audiences. When making decisions that define how audiences play a role or not in their organizations, museums must consider the far‐reaching consequences of these choices on the relationships they have with their communities.
Effect of Compliance and Backlash on the Output Speed of a Mechanical Transmission System
Authors: Dwivedula Ramamurthy V. , Pagilla Prabhakar R.
Published: April 2012

A dynamic model to describe the effect of compliance in a transmission system is presented. Analysis of this model shows that it is desirable to use feedback from driver-side of the transmission system. This model is extended to include the effects of both compliance and backlash in a mechanical transmission system. The proposed model considers compliance (which may be either due to the elasticity of the shafts or belt in a belt-pulley transmission system) and backlash appearing in series in a drive system. In contrast to the classical backlash model which considers both input and output to the backlash as displacements, the proposed model considers (torque) force as input to the backlash and (angular velocity) velocity of the driven member as the output of the backlash. Thus, the proposed model does not assume that the load is stationary when contact is lost due to backlash width, i.e., momentum of the load is taken into account. Using the proposed model, a bound on the speed error due to the presence of backlash is derived. Experiments were conducted on a rectilinear mass-spring system platform, which has a provision to change the backlash width by a known value. Experiments were conducted with different backlash widths and a velocity error bound was computed. The error bound obtained from the experimental results agrees with the theoretically computed bound.
Influence of Dispersion and Alignment of Nanotubes on the Strength and Elasticity of Carbon Nanotubes Reinforced Composites
Authors: Joshi Unnati A. , Sharma Satish C. , Harsha S. P.
Published: April 2012

In this paper, the effective strength and elastic properties of carbon nanotube reinforced composites are evaluated using a representative volume element with a number of carbon nanotubes embedded in the matrix. This concept is used to predict the mechanical properties of multiple, unidirectional, aligned, and also randomly dispersed carbon nanotube reinforced composites. To characterize these nanocomposites, a continuum model has been developed for large-scale analysis. The effective Young’s and shear moduli of the composites are determined using finite element analysis under the effect of elastic deformation. The role of design parameters like length and volume fraction of carbon nanotubes, tensile and shear strength as well as type of loading conditions are analyzed for multiple carbon nanotubes based composites. The discontinuous and continuous types of carbon nanotubes, with aligned and random distribution, are evaluated. The results show that the continuous and aligned carbon nanotubes produce the largest tensile modulus, compared to the discontinuous and aligned as well as discontinuous and randomly oriented carbon nanotubes along the longitudinal direction.
The Effect of Shape Factor on the Magnetic Targeting in the Permeable Microvessel With Two-Phase Casson Fluid Model
Authors: Shaw Sachin , Murthy P. V. S. N.
Published: April 2012

The present investigation deals with magnetic drug targeting in a microvessel of radius 5 μm using two-phase fluid model. The microvessel is divided into the endothelial glycocalyx layer wherein the blood obeys Newtonian character and a core region wherein the blood obeys the non-Newtonian Casson fluid character. The carrier particles, bound with nanoparticles and drug molecules, are injected into the vascular system upstream from the malignant tissue and are captured at the tumor site using a local applied magnetic field near the tumor position. Brinkman model is used to characterize the permeable nature of the inner wall of the microvessel. The expressions for the fluidic force for the carrier particle traversing in the two-phase fluid in the microvessel and the magnetic force due to the external magnetic field are obtained. Several factors that influence the magnetic targeting of the carrier particles in the microvasculature, such as the size and shape of the carrier particle, the volume fraction of embedded magnetic nanoparticles, and the distance of separation of the magnet from the axis of the microvessel, are considered in the present problem. The system of coupled equations is solved to obtain the trajectories of the carrier particle in the noninvasive case.
An Experimental Investigation of HCCI Combustion Stability Using n-Heptane
Authors: Li Hailin , Neill W. Stuart , Chippior Wallace L.
Published: April 2012

The combustion stability of a single-cylinder homogeneous charge compression ignition (HCCI) engine operated with n-heptane was experimentally investigated over a range of engine speeds (N), intake temperatures and pressures, compression ratios (CR), air/fuel ratios (AFR), and exhaust gas recirculation (EGR) rates. These parameters were varied to alter the combustion phasing from an overly advanced condition where engine knock occurred to an overly retarded condition where incomplete combustion was observed with excessive emissions of carbon monoxide (CO) and unburned hydrocarbons (UHC). The combustion stability was quantified by the coefficients of variation in indicated mean effective pressure (COVimep) and peak cylinder pressure (COVPmax). Cycle-to-cycle variations in the HCCI combustion behavior of this engine were shown to depend strongly on the combustion phasing, defined in this study as the crank angle position where 50% of the energy was released (CA50). In general, combustion instability increased significantly when the combustion phasing was overly retarded. The combustion phasing was limited to conditions where the COVimep was 5% or less as engine operation became difficult to control beyond this point. Based on the experimental data, the combustion phasing limit was approximately a linear function of the amount of fuel inducted in each cycle. Stable HCCI combustion could be obtained with progressively retarded combustion phasing as the fuel flow rate increased. In comparison, stable HCCI combustion was only obtained under very advanced combustion phasing for low load operating conditions. Investigation of the experimental data reveals that the cyclic variations in HCCI combustion were due to cycle-to-cycle variations in total heat release (THR). The combustion completeness of the previous cycle affected the in-cylinder bulk mixture conditions and resultant heat release process of the following engine cycle.
State Space Modeling of Variation Propagation in Multistation Machining Processes Considering Machining-Induced Variations
Authors: Abellan-Nebot José V. , Liu Jian , Subirón Fernando Romero , Shi Jianjun
Published: April 2012

In spite of the success of the stream of variation (SoV) approach to modeling variation propagation in multistation machining processes (MMPs), the absence of machining-induced variations could be an important factor that limits its application in accurate variation prediction. Such machining-induced variations are caused by geometric-thermal effects, cutting-tool wear, etc. In this paper, a generic framework for machining-induced variation representation based on differential motion vectors is presented. Based on this representation framework, machining-induced variations can be explicitly incorporated in the SoV model. An experimentation is designed and implemented to estimate the model coefficients related to spindle thermal-induced variations and cutting-tool wear-induced variations. The proposed model is compared with the conventional SoV model resulting in an average improvement on quality prediction of 67%. This result verifies the advantage of the proposed extended SoV model. The application of the new model can significantly extend the capability of SoV-model-based methodologies in solving more complex quality improvement problems for MMPs, such as process diagnosis and process tolerance allocation, etc.
Capability Estimation of Geometrical Tolerance With a Material Modifier by a Hasofer–Lind Index
Authors: Tahan Antoine S. , Cauvier Jason
Published: April 2012

This paper considers a way of measuring a process capability index in order to obtain the geometric tolerance of a pattern of position elements according to the ASME Y14.5 standard. The number of elements present in the pattern, as well as its material condition (least LMC or maximum MMC), are taken into consideration during the analysis. An explicit mathematical model will be developed to identify the distribution functions (PDF and CDF) of defects on the location and diameter. Using these distributions and the Hasofer–Lind index, we will arrive at a new definition of process capability—meaning the value of tolerances that can meet the threshold of x% compliance. Finally, our method is validated using a variety of typical case studies.
The Effects of Cutting Speed and Depth of Cut on Machinability Characteristics of Austempered Ductile Iron
Authors: Akdemir Ahmet , Yazman Şakir , Saglam Hacı , Uyaner Mesut
Published: April 2012

Ductile iron can acquire enhanced thermal and mechanical properties from austempering heat treatment. The present study aims to identify the function of different cutting parameters affecting machinability and to quantify its effects. Turning was performed to test machinability according to the ISO3685-1993 (E) standard. After austenitizing at 900 °C for 90 min, austempered ductile iron (ADI) specimens were quenched in a salt bath at 380 °C for 90 min. The cutting force signals along three directions were measured in real time, whereas flank wear and surface roughness were measured offline. For the cutting parameters, the cutting speed and depth of cut were varied, but the feed rate was kept constant. In the flank wear tests, machining length was corresponded to tool life. In addition, in order to find out the effect of cutting parameters on surface roughness (Ra), tangential force (Ft), and flank wear (VB) during turning, response surface methodology (RSM) was utilized by using experimental data. The effect of the depth of cut on the surface roughness was negligible but considerable in the cutting forces. The increased cutting speed produced a positive effect on surface roughness. It is found that the cutting speed was the dominant factor on the surface roughness, tangential force, and flank wear.
Response and Stability Analysis of Periodic Delayed Systems With Discontinuous Distributed Delay
Authors: Bobrenkov Oleg A. , Nazari Morad , Butcher Eric A.
Published: April 2012

In this paper, the analysis of delay differential equations with periodic coefficients and discontinuous distributed delay is carried out through discretization by the Chebyshev spectral continuous time approximation (ChSCTA). These features are introduced in the delayed Mathieu equation with discontinuous distributed delay which is used as an illustrative example. The efficiency of stability analysis is improved by using shifted Chebyshev polynomials for computing the monodromy matrix, as well as the adaptive meshing of the parameter plane. An idea for a method for numerical integration of periodic DDEs with discontinuous distributed delay based on existing MATLAB functions is proposed.
Study of Small Scale Effects on the Nonlinear Vibration Response of Functionally Graded Timoshenko Microbeams Based on the Strain Gradient Theory
Authors: Ansari R. , Gholami R. , Sahmani S.
Published: April 2012

In the current study, the nonlinear free vibration behavior of microbeams made of functionally graded materials (FGMs) is investigated based on the strain gradient elasticity theory and von Karman geometric nonlinearity. The nonclassical beam model is developed in the context of the Timoshenko beam theory which contains material length scale parameters to take the size effect into account. The model can reduce to the beam models based on the modified couple stress theory (MCST) and the classical beam theory (CBT) if two or all material length scale parameters are taken to be zero, respectively. The power low function is considered to describe the volume fraction of the ceramic and metal phases of the FGM microbeams. On the basis of Hamilton’s principle, the higher-order governing differential equations are obtained which are discretized along with different boundary conditions using the generalized differential quadrature method. The dimensionless linear and nonlinear frequencies of microbeams with various values of material property gradient index are calculated and compared with those obtained based on the MCST and an excellent agreement is found. Moreover, comparisons between the various beam models on the basis of linear and nonlinear types of strain gradient theory (SGT) and MCST are presented and it is observed that the difference between the frequencies obtained by the SGT and MCST is more significant for lower values of dimensionless length scale parameter.
Analysis of the Most Effective Energy Efficiency Opportunities in Manufacturing Primary Metals, Plastics, and Textiles Small- and Medium-Sized Enterprises
Authors: Cagno Enrico , Trianni Andrea
Published: April 2012

Governments are pursuing a variety of measures to reach common and more efficient environmental and energetic policies: Nonetheless, the effort has shown to be not sufficient, since the objectives stated in the European Union (EU) Directive 2009/28/EC on energy efficiency seem quite distant to be reached. A greater attention has obviously been paid toward the industrial sector, which utilizes a major share of primary energy consumption: Till now several actions have been taken to achieve the energy performance of buildings, but very few are in operations. Nonetheless, in order to be most effective, governments should focus their attention not only on energy intensive large enterprises (LEs) but also on nonenergy intensive small and medium enterprises (SMEs) that represent the majority of the total number of industries, cover a consistent share of the energy consumption of a whole domestic industrial sector, and are usually less efficient than LEs. This paper aims to highlight the most effective energy savings opportunities (ESOs) for reducing energy consumption in industrial operations that have been successfully implemented in a large number of SMEs case studies investigated in North America and Italy, showing a correspondence (in terms of savings and costs) between the two databases. This paper analyzes the ESOs, characterized by best available technologies and practices (BAT/Ps), with a cross-analysis within three manufacturing sectors, i.e., primary metals, plastics, and textiles, and considering different subsizes among SMEs, in order to show commonalities and differences among the sample. The ESOs have been analyzed and ranked according to different criteria of importance, highlighting the most diffused, those having the highest energy savings, and those with the shortest pay-back time. The scope of the elaboration of these criteria is twofold: on one side, it allows to be closer to the entrepreneurial sensibility, guiding entrepreneurs in evaluating a possible investment in energy efficiency; on the other side, it provides important suggestions for a public local authority that, through financial support and/or other policies, aims at diffusing the adoption of BAT/Ps and increasing the sectors’ energy efficiency and competitiveness.
On Sources of Error in Finite Element Simulations of Blast Effects in the Human Brain
Authors: Petr Krysl , Bondi Mark W. , Ward Samuel R. , Frank Lawrence R.
Published: April 2012

Recent military conflicts in Iraq and Afghanistan have resulted in an increase in the number of blast related traumatic brain injuries (blast-TBI). It is assumed that the primary mechanism for blast-TBI is the interaction between the blast pressure wave and the central nervous system, but the details of this mechanism are poorly understood. The conditions of such blast injuries are highly variable, and the presence or absence of protective devices such as vehicles or helmets is presumed to have a strong influence on pressure waves. Because of the complexity of this problem and the difficulty of in situ measurement of these effects in actual combat scenarios, one approach is to develop efficient numerical simulations that have the fidelity to reliably model the interaction of the brain and the pressure and shear waves. Here we examine the distribution of pressures and principal strains (stretches) in a brain impinged upon by a blast wave incident from orthogonal directions as simulated by a finite element coupled fluid-solid dynamic interaction framework. We assess the various sources of errors in finite element simulations of wave propagating through tissue, the modeling error, the discretization error, and the error of input parameters (data uncertainty). We conclude that the least important source of error is the assumption of linear kinematics and linear constitutive equation. The discretization error is significant, and controlling it will remain a challenge. The most significant source of error is found to be the input parameter uncertainty (experimental variability) and lack of knowledge of the detailed mechanics of deformation of the brain tissues under conditions of blast loading.
Pseudomonas
Biofilms, Cystic Fibrosis, and Phage: a Silver Lining?
Authors: Brüssow Harald
Published: April 2012

In contrast to usual laboratory conditions, most bacteria in the human body grow in biofilms. Encased in a structured matrix, many pathogens display heightened resistance to antibiotics.
Pseudomonas aeruginosa
lung infections in cystic fibrosis patients represent a prime example of the clinical challenges that antibiotic resistance in biofilms can represent. In the March 6, 2012 issue of
mBio
, Colin Hill and his colleagues report on experiments that add to the evidence that
Pseudomonas
phages are a potential treatment option for these infections.
Evaluation of dam overtopping risk based on univariate and bivariate flood frequency analyses
Authors: Goodarzi Ehsan , Mirzaei Majid , Ziaei Mina
Published: April 2012

There is a growing tendency to assess safety of dams by mathematical and statistical methods in hydrosystem engineering. This research presents the application of risk and uncertainty analysis to dam overtopping based on univariate and bivariate flood frequency analyses by applying Gumbel logistic distribution. The bivariate frequency analyses produced six inflow hydrographs with a joint return period of 100 years. Afterward, the overtopping risk of the Doroudzan Dam was evaluated for all six inflow hydrographs by considering quantile of flood peak discharge, initial depth of water in the reservoir, and discharge coefficient of spillway as uncertain variables and using two uncertainty analysis methods; Monte Carlo simulation and Latin hypercube sampling. Finally, the results of both univariate and bivariate frequency analyses were compared to show the significance of bivariate analysis on dam overtopping.
Can the National Classification System for Contaminated Sites be used to rank sites?
Authors: Thiessen Ron J. , Achari Gopal
Published: April 2012

In this paper, the ability of the National Classification System for Contaminated Sites (NCSCS) to rank contaminated sites has been investigated by comparing NCSCS score ranks to preliminary quantitative risk assessment (PQRA) result ranks. A recently published hierarchical partial order ranking procedure was applied to hazard quotients from PQRAs to generate ranks. Using data from 20 federal contaminated sites, the study showed that sites with low and high NCSCS score ranks correspond reasonably with low and high PQRA results ranks though there is scatter amongst the data in mid-ranges. Although the output from both the NCSCS and PQRAs have significant uncertainties, the study concludes that indeed the NCSCS can be used to rank sites. A figure is provided indicating the probability that a site with a higher NCSCS score will have a higher rank, as per PQRA.
Eliciting cross-neutralizing antibodies in mice challenged with a dengue virus envelope domain III expressed inEscherichia coli
Authors: Yang Jie , Zhang Junlei , Chen Wei , Hu Zhen , Zhu Junmin , Fang Xin , Yuan Wenchang , Li Ming , Hu Xiaomei , Tan Yinling , Hu Fuquan , Rao Xiancai
Published: April 2012

Dengue viruses (DENVs) are mosquito-borne infectious pathogens that pose a serious global public health threat, and at present, no therapy or effective vaccines are available. Choosing suitable units as candidates is fundamental for the development of a dengue subunit vaccine. Domain III of the DENV-2 E protein (EDIII) was chosen in the present study and expressed in Escherichia coli by N-terminal fusion to a bacterial leader (pelB), and C-terminal fusion with a 6×His tag based on the functions of DENV structure proteins, especially the neutralizing epitopes on the envelope E protein. After two-step purification using Ni–NTA affinity and cation-exchange chromatography, the His-tagged EDIII was purified up to 98% homogenicity. This recombinant EDIII was able to trigger high levels of neutralizing antibodies in both BALB/c and C57BL/6 mice. Both the recombinant EDIII and its murine antibodies protected Vero cells from DENV-2 infection. Interestingly, the recombinant EDIII provides at least partial cross-protection against DENV-1 infection. In addition, the EDIII antibodies were able to protect suckling mice from virus challenge in vivo. These data suggest that a candidate molecule based on the small EDIII protein, which has neutralizing epitopes conserved among all 4 DENV serotypes, has important implications.
Hydrogen cyanide synthesis and antifungal activity of the biocontrol strainPseudomonas fluorescensIn5 from Greenland is highly dependent on growth medium
Authors: Michelsen Charlotte Frydenlund , Stougaard Peter
Published: April 2012

Hydrogen cyanide (HCN) is a secondary metabolite produced by many antagonistic Pseudomonas species. In the present study, the gene cluster encoding HCN synthesis in a newly isolated Pseudomonas fluorescens strain, In5, from South Greenland was investigated. Sequence analysis showed that the Greenlandic hcn gene cluster comprises a novel hcn cluster. Transposon mutagenesis of strain In5 resulted in mutants In5-2E1 and In5-1H7 with no production of HCN, and mutant In5-6B9 with reduced HCN synthesis. In mutant In5-2E1, the transposon was inserted into the hcnC gene; in mutant In5-1H7, the Tn5 insertion was found in a region upstream of a putative malate:quinone oxidoreductase gene (mqo); and in mutant In5-6B9, the transposon disrupted a probable enoyl-CoA hydratase/isomerase gene. In vitro inhibition experiments with In5 (wild type) and In5-2E1 (mutant) showed that in nitrogen-rich Luria–Bertani medium, strain In5 but not the hcn mutant In5-2E1 produced HCN and inhibited the growth of hyphae of Rhizoctonia solani and Pythium aphanidermatum . In contrast, when cultivating the strains in the carbohydrate-rich potato dextrose medium, neither of the strains produced any HCN, and thus, they were unable to inhibit hyphal growth of fungi. These experiments strongly indicate that the synthesis of HCN is highly dependent on the growth medium used.
A potential role of Escherichia coli pathobionts in the pathogenesis of pediatric inflammatory bowel disease
Authors: Schippa Serena , Iebba Valerio , Totino Valentina , Santangelo Floriana , Lepanto Mariastefania , Alessandri Claudia , Nuti Federica , Viola Franca , Di Nardo Giovanni , Cucchiara Salvatore , Longhi Catia , Conte Maria Pia
Published: April 2012

Through genomic analysis of mucosa-associated Escherichia coli strains, we found a close genetic association among isolates from pediatric inflammatory bowel disease (IBD) patients. A specific E. coli pathovar, adherent–invasive E. coli (AIEC), was found in Crohn’s disease (CD) adult patients — this pathovar has enhanced adhesive and invasive properties, mainly due to the mannose-bonding FimH protein. We aimed to characterize 52 mucosa-associated E. coli strains isolated from pediatric IBD and non-IBD patients. Eleven E. coli strains, showing a strong similarity in fimH gene sequence to that of E. coli AIEC LF82, were characterized for fimH gene sequence, genomic profiling, adhesive and invasive ability, and phylogrouping. The results were compared with E. coli strains AIEC LF82 and MG1655. The 11 E. coli isolates showed 82.4% ± 1.4% fimH sequence similarity and 80.6% ± 1.3% genomic similarity to strain AIEC LF82. All these strains harbored V27A and S78N FimH mutations, as found in LF82. Nine of them belonged to the more virulent B2 and D phylogroups. Neuraminidase treatment, mimicking inflamed mucosa, enhanced adhesion of all 11 strains by 3.5-fold, but none showed invasion ability. It could be argued that the 11 selected strains could be a branch of an E. coli subpopulation (pathobionts), that could take advantage in an inflamed context because of a suitable genomic and (or) genetic backdrop.
THREE-DIMENSIONAL KLEIN–GORDON OSCILLATOR IN A BACKGROUND MAGNETIC FIELD IN NONCOMMUTATIVE PHASE SPACE
Authors: LIANG MAI-LIN , YANG RUI-LIN
Published: April 2012

In noncommutative phase space, wave functions and energy spectra are derived for the three-dimensional (3D) Klein–Gordon oscillator in a background magnetic field. The raising and lowering operators for this system are derived from the Heisenberg equations of motion for a 3D nonrelativistic oscillator. The coherent states are obtained as the eigenstates of the lowering operators and it is found that the coherent states are not the minimum uncertainty states due to the noncommutativity of the space. It is also pointed out that in the semiclassical limit, quantum matrix elements give solutions to the semiclassical equations.
NEW DISCUSSIONS CHALLENGE THE ORGANIZATION OF SOCIETIES
Authors: GARGIULO F. , HUET S.
Published: April 2012

Can the discussions about new issues challenge the organization of a society? That is, the question we tried to answer with a very simple model considering a society where individuals are organized into groups. An individual discuss its opinion on this new issue following the rule of the bounded confidence model implying that an individual influences and is influenced when it is sufficiently open-minded. One of the main ingredients of the model is the groups that both influence the behavior of the individual and characterize the social network topology. Individuals choose the group membership according to their opinion. Starting from an initial homogeneous group size distribution, four different prototypical regimes can be reproduced by the model, depending on the individual open-mindedness: From a high heterogeneity condition, with one or two largely major groups, to an invariant situation of homogeneity. The heterogeneity is explained by the dynamics of individuals. In this paper, we extend the studies of a previous work on the argument, deepening the analysis on the internal structure of the groups and on the dynamical process itself. To do this, we analyze indicators related to the stability of the obtained virtual society. We found that the dynamics of groups is not stable when open-mindedness is small, even if the dynamics of opinions reaches equilibrium. On the other side, for larger values of the open-mindedness, both the opinion and the group dynamics stabilize. Thus, our study shows that the introduction of a new topic of discussion in a society can strongly challenge group structures, both concerning their stability and their size.
Advanced Nanoemulsions
Authors: Fryd Michael M. , Mason Thomas G.
Published: April 2012

Recent advances in the growing field of nanoemulsions are opening up new applications in many areas such as pharmaceuticals, foods, and cosmetics. Moreover, highly controlled nanoemulsions can also serve as excellent model systems for investigating basic scientific questions about soft matter. Here, we highlight some of the most recent developments in nanoemulsions, focusing on methods of formation, surface modification, material properties, and characterization. These developments provide insight into the substantial advantages that nanoemulsions can offer over their microscale emulsion counterparts.
Attosecond Science: Recent Highlights and Future Trends
Authors: Gallmann Lukas , Cirelli Claudio , Keller Ursula
Published: April 2012

We review the first ten years of attosecond science with a selection of recent highlights and trends and give an outlook on future directions. After introducing the main spectroscopic tools, we give recent examples of representative experiments employing them. Some of the most fundamental processes in nature have been studied with some results initiating controversial discussions. Experiments on the dynamics of single-photon ionization illustrate the importance of subtle effects on such extreme timescales and lead us to question some of the well-established assumptions in this field. Attosecond transient absorption, as the first all-optical approach to resolve attosecond dynamics, has been used to study electron wave packet interferences in helium. The attoclock, a recent method providing attosecond time resolution without the explicit need for attosecond pulses, has been used to investigate electron tunneling dynamics and geometry. Pushing the frontiers in attosecond quantum mechanics with increasing temporal and spatial resolution and often limited theoretical models results in unexpected observations. At the same time, attosecond science continues to expand into more complex solid-state and molecular systems, where it starts to have impact beyond its traditional grounds.
Extensivity of Energy and Electronic and Vibrational Structure Methods for Crystals
Authors: Hirata So , Keçeli Murat , Ohnishi Yu-ya , Sode Olaseni , Yagi Kiyoshi
Published: April 2012

A pedagogical proof is presented for the extensivity of energies of metallic and nonmetallic crystals that proceeds by elucidating the asymptotic distance dependence of the effective chemical interactions: kinetic, Coulomb, exchange, and correlation. On this basis, a guideline for the size-consistent design of electronic and vibrational methods is proposed. This guideline underscores the significance of the distinct use of the intermediate and standard normalization of wave functions for extensive and intensive quantities, includes the extensive and intensive diagram theorems as the unambiguous criteria for determining size consistency of a method for extensive and intensive quantities, and introduces the extensive-intensive consistency theorem, which stipulates the precise balance between the determinant spaces reached by extensive and intensive operators. Electronic and vibrational methods for crystals are reviewed that are inspired by these formal analyses or developed in accordance with the guideline.
Membrane Protein Structure and Dynamics from NMR Spectroscopy
Authors: Hong Mei , Zhang Yuan , Hu Fanghao
Published: April 2012

We review the current state of membrane protein structure determination using solid-state nuclear magnetic resonance (NMR) spectroscopy. Multidimensional magic-angle-spinning correlation NMR combined with oriented-sample experiments has made it possible to measure a full panel of structural constraints of membrane proteins directly in lipid bilayers. These constraints include torsion angles, interatomic distances, oligomeric structure, protein dynamics, ligand structure and dynamics, and protein orientation and depth of insertion in the lipid bilayer. Using solid-state NMR, researchers have studied potassium channels, proton channels, Ca2+ pumps, G protein–coupled receptors, bacterial outer membrane proteins, and viral fusion proteins to elucidate their mechanisms of action. Many of these membrane proteins have also been investigated in detergent micelles using solution NMR. Comparison of the solid-state and solution NMR structures provides important insights into the effects of the solubilizing environment on membrane protein structure and dynamics.
Visualizing Cell Architecture and Molecular Location Using Soft X-Ray Tomography and Correlated Cryo-Light Microscopy
Authors: McDermott Gerry , Le Gros Mark A. , Larabell Carolyn A.
Published: April 2012

Living cells are structured to create a range of microenvironments that support specific chemical reactions and processes. Understanding how cells function therefore requires detailed knowledge of both the subcellular architecture and the location of specific molecules within this framework. Here we review the development of two correlated cellular imaging techniques that fulfill this need. Cells are first imaged using cryogenic fluorescence microscopy to determine the location of molecules of interest that have been labeled with fluorescent tags. The same specimen is then imaged using soft X-ray tomography to generate a high-contrast, 3D reconstruction of the cells. Data from the two modalities are then combined to produce a composite, information-rich view of the cell. This correlated imaging approach can be applied across the spectrum of problems encountered in cell biology, from basic research to biotechnological and biomedical applications such as the optimization of biofuels and the development of new pharmaceuticals.