bluuebunny/crossref_metadata_2025 huggingface dataset:
National characteristics: innovation systems from the process efficiency perspective
Authors: Liu John S. , Lu Wen‐Min , Ho Mei Hsiu‐Ching
Published: August 2014

This study compares the innovation system characteristics of 40 countries from the perspective of process efficiency. We treat the national innovation system as a two‐stage process that first produces knowledge and then commercializes the knowledge produced. After identifying efficiencies through data envelopment analysis, the within‐country strengths, or the contribution of the individual process factor to the efficiency, of all 40 target countries are compared by applying the network‐based ranking method. The comparison is different from previous efficiency‐based studies in that it hints at country characteristics and highlights the cross‐country benchmarks for each process factor. The pattern of within‐country strengths underlines the characteristic of each country. Based on country characteristics, we highlight the national differences and categorize the target countries into nine distinctive groups. We find that no single country demonstrates characteristics that focus on both the knowledge production and knowledge commercialization stages. The results provide policy makers with both references on what to improve and information for where to learn the experience from.
The idiosyncrasy of research and development efficiency across types of small‐ and medium‐sized enterprises: evidence from Korea
Authors: Lee Keeeun , Yoon Byungun
Published: August 2014

Small‐ and medium‐sized enterprises (SMEs) are considered to be the main driving force behind economic and employment growth. However, the low productivity levels of SMEs cannot be explained by lower levels of R&D investment, but are instead a consequence of a lack of research and development (R&D) efficiency that would have been adequate for making firms more competitive. To investigate any differences in R&D efficiency that impact the company overall performance in economic and employment performance, we analyze various types of SMEs in Korea. This paper applies two estimation methods: data envelopment analysis and regression analysis. This study takes three relevant factors of output: (1) the number of patents, (2) the number of success in terms of technology development, and (3) the level of profit attained through new products. Additionally, the study's model incorporates three parts of input: (1) human resources, (2) development periods, and (3) R&D budget. In the context of this paper, a comparison of the factors regarding efficiency is performed based upon the following criteria: the level of novelty, the length of a product's life cycle, and the time period of a competitor emulation of the product created by original enterprise. Comparing the factors that influence the efficiency of types within each criterion is meaningful in analyzing the differences in efficiency outcome on the various types among SMEs. Our findings indicate that SMEs vary among types in terms of efficiency and that there are also differences causing factors according to types.
Giving fish or teaching to fish? An empirical study of the effects of government research and development policies
Authors: Xu Kai , Huang Kuo‐Feng , Xu Erming
Published: August 2014

This study compares how government research and development (R&D) subsidy and knowledge transfer from universities and public research institutions stimulate a firm's new product development. More importantly, we emphasize that the effects of these governmentalR&Dpolicies on new product development can be achieved not only directly, but also via a mediating role – a firm's innovation capability. Furthermore, we test how other external knowledge sources (such as knowledge from universities and public research institutions) interact with governmentR&Dsupport to stimulate new product development. The results, based on an investigation of 270Chinese firms, suggest that both governmentR&Dsubsidy and knowledge transfer from universities and public research institutions enhance new product development. The results also show that although governmentR&Dsubsidy and knowledge transfer from universities and public research institutions has a direct impact on new product development, innovation capability does mediate the above relationships. Moreover, unlike the findings that other external knowledge sources have a direct influence on new product development as indicated by the previous literature, our findings suggest that external knowledge sources substitute with the governmentR&Dsubsidies and complement with knowledge transfer from universities and public research institutions. The results confirm the old sayings that teaching to fish (knowledge transfer from universities and public research institutions can complement with other external knowledge sources) is much better than giving fish (governmentR&Dsubsidies substitute other external knowledge sources). This paper enriches current literature of governmentR&Dsupport policies to firm new product development by providing empirical evidences.
Temporal changes of soil physical quality under two residue management systems
Authors: Castellini M. , Niedda M. , Pirastru M. , Ventrella D.
Published: August 2014

Although crop residue management is known to affect near‐surface soil physical quality, little is known about the temporal variability of these indicators over short time intervals. This study evaluates the temporal changes of nine indicators of soil physical quality. These are organic carbon content, structural stability index, bulk density, macroporosity, air capacity, relative field capacity, plant available water capacity, Dexter's S‐index and saturated hydraulic conductivity. A second set of soil physical indicators, based on the distribution of soil pore volume, was also evaluated. The indicators were determined in three different times during the growing cycle of winter durum wheat cultivated within a long‐term field research carrying out in Southern Italy and comparing two types of crop residue management, that is, burning (B) and soil incorporation (I). Only the bulk density changed over time for both treatments, although the air capacity also changed for the incorporation of wheat residues. Residual effects of the autumnal soil tillage and soil compaction were a common source of variability, irrespective of which treatment was used. Based on the existing guidelines for evaluating the physical quality of these agricultural soils, optimal or near‐optimal values were detected in about half of the cases under consideration. This suggests that both B and I create sufficiently good conditions for crop growth during the crop cycle. The comparison between observed and optimal soil pore distribution function was always poor. The pore volume distributions showed lower densities of small pores and relatively higher densities of large pores than the proposed optimal distribution. This study also suggests that the considered optimal or references curves probably cannot be applied successfully to a wide range of agricultural soils.
Identification of the novel KIR3DL1*01505 allele from southern Chinese Han individual
Authors: Wang D. , Zhen J. , Deng Z.
Published: August 2014

The novel KIR3DL1*01505 allele differs from the closest allele KIR3DL1*0150201 by a single silent mutation.
Predonation screening of candidate donors and prevention of window period donations
Authors: Lieshout‐Krikke Ryanne W. , Zaaijer Hans L. , van de Laar Thijs J.W.
Published: August 2014

Background

Infectious window period donations slip through routine donor screening procedures. To explore the potential value of predonation screening of candidate donors, we compared the proportion of incident transfusion‐transmissible infections in candidate donors, in first‐time donors, and in repeat donors.

Study Design and Methods

A retrospective analysis was performed of all incident hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV) infections in candidate, first‐time, and repeat donors in the Netherlands during the period 2009 to 2013.

Results

In total, 176,716 candidate donors, 144,226 first‐time donations, and 4,143,455 repeat donations were screened for HBV, HCV, and HIV infection. Acute HBV infection was identified in the predonation sample of six candidate donors. One first‐time donor, testing HIV‐negative at predonation screening, tested positive for anti‐HIV and HIV RNA in the first donation 29 days later. Among repeat donations we identified 15, one, and six incident HBV, HCV and HIV infections, respectively. The proportion of incident infections among candidate donors/first‐time donations/repeat donations was for HBV, 3.40/0/0.36; for HCV, 0/0/0.02; and for HIV 0/0.69/0.14 per 100,000, respectively.

Conclusion

Predonation screening of candidate donors very likely causes a loss of donations, but it might prevent undetected window period donations. Further studies are necessary to determine the value of predonation screening as an additional safety measure.
Vasopressin regulation of epithelial colonic proliferation and permeability is mediated by pericryptal platelet‐derived growth factor A
Authors: Miró Lluïsa , Pérez‐Bosque Anna , Maijó Mònica , Naftalin Richard J. , Moretó Miquel
Published: August 2014

New Findings

What is the central question of this study?

Arginine vasopressin (AVP) regulates distal colonic crypt cell proliferation and permeability in vivo, but the underlying mechanism is poorly understood. Our study addresses whether AVP is acting directly on myofibroblasts and enterocytes or by mechanisms involving local regulators, in an in vitro model using human myofibroblasts and enterocyte cell lines.

What is the main finding and its importance?

The effect of AVP in stimulating myofibroblast proliferation involves pericryptal platelet‐derived growth factor A, which mediates local effects by an autocrine loop and epithelial proliferation and permeability by a paracrine mechanism. These data highlight the role of growth factors as local mediators of systemic hormones.

Arginine vasopressin (AVP) has trophic effects on the rat distal colon, increasing the growth of pericryptal myofibroblasts and reducing the colonic crypt wall permeability. This study aimed to reproduce in vitro the effects of AVP observed in vivo using cultures of human CCD‐18Co myofibroblasts and T84 colonic epithelial cells. Proliferation of myofibroblasts was quantified by bromodeoxyuridine incorporation; the expression of platelet‐derived growth factor A (PDGFA), platelet‐derived growth factor B, epidermal growth factor, transforming growth factor‐β and vascular endothelial growth factor was measured by PCR and the expression of epithelial junction proteins by Western blot. Arginine vasopressin stimulated myofibroblast proliferation and the expression of PDGFA without affecting the expression of platelet‐derived growth factor B, epidermal growth factor, transforming growth factor‐β or vascular endothelial growth factor. These effects were prevented when AVP receptor inhibitors were present in the medium. Pre‐incubation of CCD‐18Co cells with anti‐PDGF antibody or with an inhibitor of the PDGF receptor abolished the effects of AVP. When colonocytes were incubated with medium obtained from myofibroblasts incubated with AVP, both cell proliferation and the expression of epithelial junction proteins increased; however, direct incubation of colonocytes with AVP did not modify these variables. These results demonstrate that AVP stimulates myofibroblast proliferation and induces PDGFA secretion, implying that PDGFA mediates local myofibroblast proliferation by an autocrine feedback loop and regulates epithelial proliferation and permeability by a paracrine mechanism.
Infusion of ATP increases leg oxygen delivery but not oxygen uptake in the initial phase of intense knee‐extensor exercise in humans
Authors: Nyberg Michael , Christensen Peter M. , Mortensen Stefan P. , Hellsten Ylva , Bangsbo Jens
Published: August 2014

New Findings

What is the central question of this study?

In the transition from rest to exercise, skeletal muscle blood flow, oxygen delivery and extraction of oxygen from the blood increase to accommodate the need for additional oxygen in the contracting fibres. To what extent skeletal muscle blood flow and oxygen delivery limit the rise in skeletal muscle oxygen uptake in the initial phase of intense exercise remains controversial.

What is the main finding and its importance?

A marked increase in blood flow and oxygen delivery, induced by infusion of ATP, did not affect the increase in oxygen uptake. This finding suggests that oxygen delivery does not limit skeletal muscle oxygen uptake in the initial phase of intense exercise.

The present study examined whether an increase in leg blood flow and oxygen delivery at the onset of intense exercise would speed the rate of rise in leg oxygen uptake. Nine healthy men (25 ± 1 years old, mean ± SEM) performed one‐leg knee‐extensor exercise (62 ± 3 W, 86 ± 3% of incremental test peak power) for 4 min during a control setting (CON) and with infusion of ATP into the femoral artery in order to increase blood flow before and during exercise. In the presence of ATP, femoral arterial blood flow and O2 delivery were higher (P < 0.001) at the onset of exercise and throughout exercise (femoral arterial blood flow after 10 s, 5.1 ± 0.5 versus 2.7 ± 0.3 l min−1; after 45 s, 6.0 ± 0.5 versus 4.1 ± 0.4 l min−1; after 90 s, 6.6 ± 0.6 versus 4.5 ± 0.4 l min−1; and after 240 s, 7.0 ± 0.6 versus 5.1 ± 0.3 l min−1 in ATP and CON conditions, respectively). Leg oxygen uptake was not different in ATP and CON conditions during the first 20 s of exercise but was lower (P < 0.05) in the ATP compared with CON conditions after 30 s and until the end of exercise (30 s, 436 ± 42 versus 549 ± 45 ml min−1; and 240 s, 705 ± 31 versus 814 ± 59 ml min−1 in ATP and CON, respectively). Lactate release was lower after 60, 120 and 180 s of exercise with ATP infusion. These results suggest that O2 delivery is not limiting the rise in skeletal muscle oxygen uptake in the initial phase of intense exercise.
Ultrasonic Attenuation Based Inspection Method for Scale-up Production of A206–Al2O3 Metal Matrix Nanocomposites
Authors: Wu Jianguo , Zhou Shiyu , Li Xiaochun
Published: August 2014

A206–Al2O3 metal matrix nanocomposite (MMNC) is a promising high performance material with potential applications in various industries, such as automotive, aerospace, and defense. Al2O3 nanoparticles dispersed into molten Al using ultrasonic cavitation technique can enhance the nucleation of primary Al phase to reduce its grain size and modify the secondary intermetallic phases. To enable a scale-up production, an effective yet easy-to-implement quality inspection technique is needed to effectively evaluate the resultant microstructure of the MMNCs. At present the standard inspection technique is based on the microscopic images, which are costly and time-consuming to obtain. This paper investigates the relationship between the ultrasonic attenuation and the microstructures of pure A206 and Al2O3 reinforced MMNCs with/without ultrasonic dispersion. A hypothesis test based on an estimated attenuation variance was developed and it could accurately differentiate poor samples from good ones. This study provides useful guidelines to establish a new quality inspection technique for A206–Al2O3 nanocomposites using ultrasonic nondestructive testing method.
The Correlation of the Volumetric Wear Rate of Turning Tool Inserts With Carbide Grain Sizes
Authors: Kuttolamadom Mathew A. , Laine Mears M. , Kurfess Thomas R.
Published: August 2014

The objective of this paper is to analyze the effect of different carbide grain sizes on the tool material volume worn away from straight tungsten–carbide–cobalt (WC–Co) turning inserts. A previously developed metrology method for assessing the tool material volume worn away from milling inserts is adapted for quantifying the volumetric tool wear (VTW) of turning inserts. Controlled turning experiments are conducted at suitable points in the feed-speed design space for two sets of uncoated inserts having different carbide grain sizes. Three levels of Ti–6Al–4V stock removal volumes (10-cm3 each) are analyzed. For each insert, the tool material volume worn away (in mm3) as well as the three-dimensional (3D) wear profile evolution is quantified after each run. Further, the specific volumetric wear rate and the M-ratio (volume of stock removed to VTW) are related to the material removal rate (MRR). The effect of carbide grain size on VTW is examined using scanning electron microscopy and elemental analysis. Finally, the inverse dependence of the M-ratio on MRR enables the definition of actual usable tool life in terms of its efficiency in removing stock, rather than being based on a tool geometry related metric.
Kinematics and Interfacing of ModRED: A Self-Healing Capable, 4DOF Modular Self-Reconfigurable Robot
Authors: Hossain S. G. M. , Nelson Carl A. , Chu Khoa D. , Dasgupta Prithviraj
Published: August 2014

Modular self-reconfigurable robots (MSRs) are systems which rely on modularity for maneuvering over unstructured terrains, while having the ability to complete multiple assigned functions in a distributed way. An MSR should be equipped with robust and efficient docking interfaces to ensure enhanced autonomy and self-reconfiguration ability. Genderless docking is a necessary criterion to maintain homogeneity of the robot modules. This also enables self-healing of a modular robot system in the case of a failed module. The mechanism needs to be compact and lightweight and at the same time have sufficient strength to transfer loads from other connected modules. This research focuses on the design of a modular robot with four degrees of freedom (4DOF) per module and with the goal of achieving higher workspace flexibility and self-healing capability. To explain the working principle of the robot, forward kinematic transformations were derived and workspace and singularity analysis were performed. In addition, to address the issues of interfacing, a rotary plate genderless single-sided docking mechanism—RoGenSiD—was developed. The design methodology included considerations for minimal space and weight as well as for fault tolerance. As a result, this docking mechanism is applicable for multifaceted docking in lattice-type, chain-type, or hybrid-type MSR systems. Several locomotion gaits were proposed and bench-top testing validated the system performance in terms of self-healing capability and generation of locomotion gaits.
Film Cooling Modeling of Turbine Blades Using Algebraic Anisotropic Turbulence Models
Authors: Li Xueying , Ren Jing , Jiang Hongde
Published: August 2014

The complex structures in the flow field of gas turbine film cooling increase the anisotropy of turbulence making it difficult to accurately compute turbulent eddy viscosity and scalar diffusivity. An algebraic anisotropic turbulence model is developed while aiming at a more accurate modeling of the Reynolds stress and turbulent scalar-flux. In this study, the algebraic anisotropic model is validated by two in-house experiments. One is a leading edge with showerhead film cooling and the other is a vane with full coverage film cooling. Adiabatic film cooling effectiveness under different blowing ratios, density ratios, and film cooling arrangements were measured using pressure sensitive paint (PSP) technique. Four different turbulence models are tested and detailed analyses of computational simulations are performed. Among all the turbulence models investigated, the algebraic anisotropic model shows better agreement with the experimental data qualitatively and quantitatively. The algebraic anisotropic model gives a good prediction of the vortex strength and turbulence mixing of the jet, therefore improves the prediction of the scalar field.
Effect of Apex Angle, Porosity, and Permeability on Flow and Heat Transfer in Triangular Porous Ducts
Authors: Negin Mortazavi S. , Hassanipour Fatemeh
Published: August 2014

This paper presents an analysis of forced convection flow and heat transfer in triangular ducts containing a porous medium. The porous medium is isotropic and the flow is laminar, fully developed with constant properties. Numerical results for velocity and temperature distribution (in dimensionless format) in the channel are presented for a wide range of porosity, permeability, and apex angles. The effects of apex angle and porous media properties (porosity and permeability) are demonstrated on the velocity and temperature distribution, as well as the friction factor (fRe) and Nusselt numbers in the channel for both Isoflux (NuH) and Isothermal (NuT) boundary conditions. The consistency of our findings has been verified with earlier results in the literature on empty triangular ducts, when the porosity in our models is made to approach one.
Fault Detection and Estimation for Electromechanical Brake Systems Using Parity Space Approach
Authors: Hwang Woohyun , Huh Kunsoo
Published: August 2014

In future, existing hydraulic braking systems will be replaced by electronic braking systems called brake-by-wire (BBW). The BBW units such as electromechanical brake (EMB) are lighter than hydraulic brakes and relatively faster in response. However, the most important issue for adopting BBW units to vehicle is the reliability of their performance. Partial or complete failure of the BBW units can cause not only dangerous situations but also liability for damages. In this study, a sensor fault diagnosis method is proposed by combining parity space and observer design approaches for EMB sensors; current sensor and position (or speed) sensor. The residual generator is constructed to detect sensor faults and fault sizes are estimated using the generated residual information. The EMB model as well as the proposed fault detection and estimation methods is verified in the EMB hardware-in-the-loop simulation (HILS) test bench.
Computational Fluid Dynamics Investigation of Turbulent Flow Inside a Rotary Double External Gear Pump
Authors: Ghazanfarian Jafar , Ghanbari D.
Published: August 2014

This article presents a numerical investigation of 2D turbulent flow within a double external gear pump. The configuration of the inlet and outlet ports is determined such that the double gear pump acts like the combination of two parallel pumps. The complex geometry of the double gear pump, existence of narrow gaps between rotating and stationary walls, and rapidly deforming flow domain make the numerical solution more complicated. In order to solve the mass, momentum, and energy conservation laws along with the k-ε turbulence model, a second-order finite volume method has been used over a dynamically varying unstructured mesh. The numerical results including pressure contours, velocity vectors, flow patterns inside the suction chamber, leakage paths, and time variation of volumetric flow rate are presented in detail. The flow rate characteristic curves with linear behavior are demonstrated at rotational speeds and outlet pressures in the range of 1500–4000 rpm and 2–80 bar, respectively. The effect of reducing the gear-casing gap-size on the augmentation of the net flow rate has been investigated. It is concluded that the minimum oil pressure within the gear pump occurs at the two places between contacting gears near the inlet ports. The contours of vapor volume fraction are also illustrated.
Why Fracking Works
Authors: Bažant Zdeněk P. , Salviato Marco , Chau Viet T. , Viswanathan Hari , Zubelewicz Aleksander
Published: August 2014

Although spectacular advances in hydraulic fracturing, also known as fracking, have taken place and many aspects are well understood by now, the topology, geometry, and evolution of the crack system remain an enigma and mechanicians wonder: Why fracking works? Fracture mechanics of individual fluid-pressurized cracks has been clarified but the vital problem of stability of interacting hydraulic cracks escaped attention. First, based on the known shale permeability, on the known percentage of gas extraction from shale stratum, and on two key features of the measured gas outflow which are (1) the time to peak flux and (2) the halftime of flux decay, it is shown that the crack spacing must be only about 0.1 m. Attainment of such a small crack spacing requires preventing localization in parallel crack systems. Therefore, attention is subsequently focused on the classical solutions of the critical states of localization instability in a system of cooling or shrinkage cracks. Formulated is a hydrothermal analogy which makes it possible to transfer these solutions to a system of hydraulic cracks. It is concluded that if the hydraulic pressure profile along the cracks can be made almost uniform, with a steep enough pressure drop at the front, the localization instability can be avoided. To achieve this kind of profile, which is essential for obtaining crack systems dense enough to allow gas escape from a significant portion of kerogen-filled nanopores, the pumping rate (corrected for the leak rate) must not be too high and must not be increased too fast. Furthermore, numerical solutions are presented to show that an idealized system of circular equidistant vertical cracks propagating from a horizontal borehole behaves similarly. It is pointed out that one useful role of the proppants, as well as the acids that promote creation of debris in the new cracks, is to partially help to limit crack closings and thus localization. To attain the crack spacing of only 0.1 m, one must imagine formation of hierarchical progressively refined crack systems. Compared to new cracks, the system of pre-existing uncemented natural cracks or joints is shown to be slightly more prone to localization and thus of little help in producing the fine crack spacing required. So, from fracture mechanics viewpoint, what makes fracking work?–the mitigation of fracture localization instabilities. This can also improve efficiency by fracturing more shale. Besides, it is environmentally beneficial, by reducing flowback per m3 of gas. So is the reduction of seismicity caused by dynamic fracture instabilities (which are more severe in underground CO2 sequestration).
Modeling of Material Removal Rate in Vibration Assisted Nano Impact-Machining by Loose Abrasives
Authors: James Sagil , Sundaram Murali M.
Published: August 2014

Vibration assisted nano impact-machining by loose abrasives (VANILA) is a novel nanomachining process that combines the principles of vibration-assisted abrasive machining, and tip-based nanomachining, to perform target specific nano abrasive machining of hard and brittle materials. An atomic force microscope (AFM) is used as a platform in this process wherein, nano abrasives, injected in slurry between the workpiece and the vibrating AFM probe, impact the workpiece and cause nanoscale material removal. The objective of this study is to develop a mathematical model to determine the material removal rate (MRR) in the VANILA process. The experimental machining results reveal that the material removal happens primarily in ductile mode due to repeated deformation which happens at near normal angles of impact. A predictive model for MRR during the VANILA process is analytically developed based on elastoplastic impact theory for normal angles of impact. The model is validated through a series of experiments performed on silicon and borosilicate glass substrates and the results confirm that the model is capable of predicting the machining results within 10% deviation.
Blade–Row Interactions in a Low Pressure Turbine at Design and Strong Off-Design Operation
Authors: Lipfert Martin , Habermann Jan , Rose Martin G. , Staudacher Stephan , Guendogdu Yavuz
Published: August 2014

In a joint project between the Institute of Aircraft Propulsion Systems (ILA) and MTU Aero Engines, a two-stage low pressure turbine is tested at design and strong off-design conditions. The experimental data taken in the Altitude Test Facility (ATF) aims to study the effect of positive and negative incidence of the second stator vane. A detailed insight and understanding of the blade row interactions at these regimes is sought. Steady and time-resolved pressure measurements on the airfoil as well as inlet and outlet hot-film traverses at identical Reynolds number are performed for the midspan streamline. The results are compared with unsteady multistage computational fluid dynamics (CFD) predictions. Simulations agree well with the experimental data and allow detailed insights in the time-resolved flow-field. Airfoil pressure field responses are found to increase with positive incidence whereas at negative incidence the magnitude remains unchanged. Different pressure to suction side (SS) phasing is observed for the studied regimes. The assessment of unsteady blade forces reveals that changes in unsteady lift are minor compared to changes in axial force components. These increase with increasing positive incidence. The wake-interactions are predominating the blade responses in all regimes. For the positive incidence conditions, vane 1 passage vortex fluid is involved in the midspan passage interaction, leading to a more distorted three-dimensional (3D) flow field.
A Control Lyapunov Approach to Finite Control Set Model Predictive Control for Permanent Magnet Synchronous Motors
Authors: Prior Gideon , Krstic Miroslav
Published: August 2014

In this paper, we present a novel model predictive control (MPC) scheme that incorporates stability information derived from a control Lyapunov function (CLF) to dynamically prune suboptimal sequences from the search space and decrease the computational burden placed on the controller. The CLF used for pruning is then incorporated into a cost function that penalizes energy in the error system as well as energy loss due to switching. Despite the very small control periods allowed due dynamic pruning, experimental results are given, showing the resulting controller generates low switching frequencies and low total harmonic distortion.
Challenges During Shallow and Deep Carbonate Reservoirs Stimulation
Authors: Mahmoud Mohamed , Nasr-El-Din Hisham
Published: August 2014

Carbonate reservoir stimulation has been carried out for years using HCl or HCl-based fluids. High HCl concentration should not be used when the well completion has Cr-based alloy in which the protective layer is chrome oxide which is very soluble in HCl. HCl or its based fluids are not recommended either in shallow reservoirs where the fracture pressure is low (face dissolution) or in deep reservoirs where it will cause severe corrosion problems to the well tubular. Different chelating agents have been proposed to be used as alternatives to HCl in the cases that HCl cannot be used. Chelating agents, such as HEDTA (hydroxyl ethylene diamine triacetic acid) and GLDA (glutamic –N, N-diacetic acid), have been used to stimulate carbonate cores. The benefits of chelating agents over HCl are the low reaction, low leak-off rate, and low corrosion rates. In this study, the different equations and parameters that can be used in matrix acid treatment were summarized to scale up the laboratory conditions to the field conditions. The conditions where HCl or chelating agents can be used were optimized and in this paper. The leak-off rate was determined using the data from coreflood experiments and computed tomography (CT) scans. Indiana limestone cores of average permeability of 1 md and core lengths of 6 and 20 in. were used in this study. Chelating agents will be used at pH value of 4 and at concentration of 0.6M, and their performance will be compared with the 15 wt.% HCl. The experimental results showed that HCl has high leak-off rate and caused face dissolution at low injection rate. The model to scale up the linear coreflood results to radial field conditions was developed and can be used to design for the optimum conditions of the matrix acid treatments. Chelating agents can be used to stimulate shallow reservoirs in which HCl may cause face dissolution, because they can penetrate deep with less volume and also they can be used in deep reservoirs where HCl may cause severe corrosion to the well tubular.
Optical system for a multiple-beam scanning electron microscope
Authors: Enyama Momoyo , Sakakibara Makoto , Tanimoto Sayaka , Ohta Hiroya
Published: August 2014

A novel optical system for a multiple-beam scanning electron microscope (SEM) is proposed. In the case of multiple-beam SEM, multiple secondary-electron beams passing through the column are inherently blurred because of the large energy spread and broad angular distribution of secondary electrons. To avoid cross-talk between the multiple secondary-electron beams, the optical system is designed such that it is divided into two independent parts: one for primary-beam illumination and one for secondary-electron detection. As the key components for the secondary-electron detection, a scan-cancelling deflector, and accelerating electric field were applied. To demonstrate the proposed optical system, a prototype column with four beams was developed. This column enables four SEM images to be separately but simultaneously acquired with more than 99% of the generated secondary electrons. This result demonstrates that high-speed imaging with the proposed multiple-beam SEM is possible in the near future.
Force Capacity of Back Extensor Muscles in Healthy Males: Effects of Age and Recovery Time
Authors: Kurz Eduard , Anders Christoph , Walther Mario , Schenk Philipp , Scholle Hans-Christoph
Published: August 2014

To judge a person’s maximum trunk extension performance as either age-appropriate or deconditioned is challenging. The current study aimed at determining age and anthropometrically adjusted maximum voluntary contraction (MVC) of back extensors considering the number and recovery time between trials. Thirty-one younger (20–30 years) and 33 older (50–60 years) healthy males performed five repetitions of maximal isometric trunk extensions in an upright standing position with randomized recovery times ranging between one to five minutes at one minute intervals. Torque values were normalized according to the individual’s upper body mass resulting in upper body torque ratios (UBTR). To evaluate the impact of age, recovery time, and fatigue on UBTR we applied a linear mixed-effects model. Based on surface EMG data muscular fatigue could be excluded for both groups. For all MVC trials, UBTR levels differed significantly between age groups (range of mean values: younger: 2.26–2.28, older: 1.78–1.87, effect size: 1.00) but were independent from recovery time. However, the older males tended to exert higher UBTR values after shorter recovery periods. The study provides normative values of anthropometrically and age-group adjusted maximum back extensor forces. For the investigated groups, only two MVC trials with a recovery time of about one minute seem appropriate.
Evaluation of West Virginia’s Healthy Lifestyles Act Physical Education Component Using the YRBSS
Authors: Pilkerton Courtney , Bias Thomas K.
Published: August 2014

Background:

Public health researchers have demonstrated the potential for significant gains in physical activity through public policy. West Virginia passed House Bill 2816, known as the Healthy Lifestyles Act in 2005. This Act amended the code on the requirements of physical education and physical fitness in schools, creating minimum physical education requirements at each grade level. The goal of this policy evaluation was to identify if, 5 years postimplementation, students have increased physical education in schools.

Methods:

Data from the 2003, 2005, 2007, 2009, and 2011 Youth Risk Behavior Surveillance System surveys were used to examine the time trend of weekly PE participation in WV Schools.

Results:

There have been no significant changes in participation in physical education classes since before the implementation of the HLA.

Conclusions:

Simple policy changes by themselves may not effectively create change in physical activity environments, as policy is moderated by strength of language, implementation, and enforcement. Further studies are needed to determine why the HLA has not been successful in increasing physical activity of youth and what changes to the standards and mandates, ways implementation in schools could be improved, and/or the enforcement of these standards are needed for such policies to be successful.
Association of Family Functioning on Youth Physical Activity and Sedentary Behavior
Authors: Loprinzi Paul D.
Published: August 2014

Objective:

High family functioning is associated with reduced depression symptoms, better academic achievement, less disordered eating, and better metabolic control among youth. However, we know very little about the role of family functioning on physical activity and sedentary behavior among youth, which was the purpose of this study.

Methods:

Data from the 2003 and 2011–2012 cycles of the National Survey of Children’s Health were used. A total of 61,226 parents/guardians from the 2003 cycle and 40,446 parents/guardians from the 2011–2012 cycle (total n = 101,672) across all 50 states and the District of Columbia were examined. Parents answered questions related to family functioning and their child’s (age 6–17 yrs) physical activity and sedentary behavior.

Results:

Results were the same across both cycles; after adjustments, youth engaged in less physical activity if the family had worse family functioning (β = −0.06, P < .001). Similarly, youth engaged in more sedentary behavior if the family had worse family functioning (β = 0.05, P < .001).

Conclusion:

This research suggests that youth are more active and engage in less sedentary behavior if their family has greater family functioning.
Centennial changes in North Pacific anoxia linked to tropical trade winds
Authors: Deutsch Curtis , Berelson William , Thunell Robert , Weber Thomas , Tems Caitlin , McManus James , Crusius John , Ito Taka , Baumgartner Timothy , Ferreira Vicente , Mey Jacob , van Geen Alexander
Published: August 2014

Climate warming is expected to reduce oxygen (O
2
) supply to the ocean and expand its oxygen minimum zones (OMZs). We reconstructed variations in the extent of North Pacific anoxia since 1850 using a geochemical proxy for denitrification (δ
15
N) from multiple sediment cores. Increasing δ
15
N since ~1990 records an expansion of anoxia, consistent with observed O
2
trends. However, this was preceded by a longer declining δ
15
N trend that implies that the anoxic zone was shrinking for most of the 20th century. Both periods can be explained by changes in winds over the tropical Pacific that drive upwelling, biological productivity, and O
2
demand within the OMZ. If equatorial Pacific winds resume their predicted weakening trend, the ocean’s largest anoxic zone will contract despite a global O
2
decline.
Long-range and local circuits for top-down modulation of visual cortex processing
Authors: Zhang Siyu , Xu Min , Kamigaki Tsukasa , Hoang Do Johnny Phong , Chang Wei-Cheng , Jenvay Sean , Miyamichi Kazunari , Luo Liqun , Dan Yang
Published: August 2014

You only see what you want to see

We often focus on a particular item out of a thousand objects in a visual scene. This ability is called selective attention. Selective attention enhances the responses of sensory nerve cells to whatever is being observed and dampens responses to any distractions. Zhang
et al.
identified a region of the mouse forebrain that modulates responses in the visual cortex. This modulation improved the mouse's performance in a visual task.

Science
, this issue p.
660
RETRACTED: Ammonia synthesis by N
2
and steam electrolysis in molten hydroxide suspensions of nanoscale Fe
2
O
3
Authors: Licht Stuart , Cui Baochen , Wang Baohui , Li Fang-Fang , Lau Jason , Liu Shuzhi
Published: August 2014

Taking carbon out of the ammonial recipe

The reaction used to make ammonia for synthetic fertilizer requires hydrogen. Nowadays, that hydrogen is stripped from methane, creating CO
2
as a by-product. Licht
et al.
demonstrate a relatively efficient electrochemical process in which water and nitrogen react directly to form ammonia. The approach removes the need for an independent hydrogen generation step. The process takes place in molten hydroxide salt and requires a nanostructured iron oxide–derived catalyst. Although the catalyst suspension is currently only stable for a few hours, the protocol points to a way to produce ammonia from purely renewable resources.

Science
, this issue p.
637
Combinatorial Strategies for Improving Multiple-Stress Resistance in Industrially Relevant Escherichia coli Strains
Authors: Lennen Rebecca M. , Herrgård Markus J.
Published: August 2014

High-cell-density fermentation for industrial production of chemicals can impose numerous stresses on cells due to high substrate, product, and by-product concentrations; high osmolarity; reactive oxygen species; and elevated temperatures. There is a need to develop platform strains of industrial microorganisms that are more tolerant toward these typical processing conditions. In this study, the growth of six industrially relevant strains of
Escherichia coli
was characterized under eight stress conditions representative of fed-batch fermentation, and strains W and BL21(DE3) were selected as platforms for transposon (Tn) mutagenesis due to favorable resistance characteristics. Selection experiments, followed by either targeted or genome-wide next-generation-sequencing-based Tn insertion site determination, were performed to identify mutants with improved growth properties under a subset of three stress conditions and two combinations of individual stresses. A subset of the identified loss-of-function mutants were selected for a combinatorial approach, where strains with combinations of two and three gene deletions were systematically constructed and tested for single and multistress resistance. These approaches allowed identification of (i) strain-background-specific stress resistance phenotypes, (ii) novel gene deletion mutants in
E. coli
that confer single and multistress resistance in a strain-background-dependent manner, and (iii) synergistic effects of multiple gene deletions that confer improved resistance over single deletions. The results of this study underscore the suboptimality and strain-specific variability of the genetic network regulating growth under stressful conditions and suggest that further exploration of the combinatorial gene deletion space in multiple strain backgrounds is needed for optimizing strains for microbial bioprocessing applications.
Golgi UDP-GlcNAc:Polypeptide
O
-α-
N
-Acetyl-
d
-Glucosaminyltransferase 2 (TcOGNT2) Regulates Trypomastigote Production and Function in Trypanosoma cruzi
Authors: Koeller Carolina M. , van der Wel Hanke , Feasley Christa L. , Abreu Fernanda , da Rocha Juliana Dutra Barbosa , Montalvão Fabrício , Fampa Patrícia , dos Reis Flávia C. G. , Atella Georgia C. , Souto-Padrón Thaís , West Christopher M. , Heise Norton
Published: August 2014

All life cycle stages of the protozoan parasite
Trypanosoma cruzi
are enveloped by mucin-like glycoproteins which, despite major changes in their polypeptide cores, are extensively and similarly
O
-glycosylated.
O
-Glycan biosynthesis is initiated by the addition of αGlcNAc to Thr in a reaction catalyzed by Golgi UDP-GlcNAc:polypeptide
O
-α-
N
-acetyl-
d
-glucosaminyltransferases (ppαGlcNAcTs), which are encoded by
TcOGNT1
and
TcOGNT2
. We now directly show that TcOGNT2 is associated with the Golgi apparatus of the epimastigote stage and is markedly downregulated in both differentiated metacyclic trypomastigotes (MCTs) and cell culture-derived trypomastigotes (TCTs). The significance of downregulation was examined by forced continued expression of TcOGNT2, which resulted in a substantial increase of TcOGNT2 protein levels but only modestly increased ppαGlcNAcT activity in extracts and altered cell surface glycosylation in TCTs. Constitutive TcOGNT2 overexpression had no discernible effect on proliferating epimastigotes but negatively affected production of both types of trypomastigotes. MCTs differentiated from epimastigotes at a low frequency, though they were apparently normal based on morphological and biochemical criteria. However, these MCTs exhibited an impaired ability to produce amastigotes and TCTs in cell culture monolayers, most likely due to a reduced infection frequency. Remarkably, inhibition of MCT production did not depend on TcOGNT2 catalytic activity, whereas TCT production was inhibited only by active TcOGNT2. These findings indicate that TcOGNT2 downregulation is important for proper differentiation of MCTs and functioning of TCTs and that TcOGNT2 regulates these functions by using both catalytic and noncatalytic mechanisms.
Comparative Evaluation of Two Commercial Multiplex Panels for Detection of Gastrointestinal Pathogens by Use of Clinical Stool Specimens
Authors: Khare Reeti , Espy Mark J. , Cebelinski Elizabeth , Boxrud David , Sloan Lynne M. , Cunningham Scott A. , Pritt Bobbi S. , Patel Robin , Binnicker Matthew J.
Published: August 2014

The detection of pathogens associated with gastrointestinal disease may be important in certain patient populations, such as immunocompromised hosts, the critically ill, or individuals with prolonged disease that is refractory to treatment. In this study, we evaluated two commercially available multiplex panels (the FilmArray gastrointestinal [GI] panel [BioFire Diagnostics, Salt Lake City, UT] and the Luminex xTag gastrointestinal pathogen panel [GPP] [Luminex Corporation, Toronto, Canada]) using Cary-Blair stool samples (
n
= 500) submitted to our laboratory for routine GI testing (e.g., culture, antigen testing, microscopy, and individual real-time PCR). At the time of this study, the prototype (non-FDA-cleared) FilmArray GI panel targeted 23 pathogens (14 bacterial, 5 viral, and 4 parasitic), and testing of 200 μl of Cary-Blair stool was recommended. In contrast, the Luminex GPP assay was FDA cleared for the detection of 11 pathogens (7 bacterial, 2 viral, and 2 parasitic), but had the capacity to identify 4 additional pathogens using a research-use-only protocol. Importantly, the Luminex assay was FDA cleared for 100 μl raw stool; however, 100 μl Cary-Blair stool was tested by the Luminex assay in this study. Among 230 prospectively collected samples, routine testing was positive for one or more GI pathogens in 19 (8.3%) samples, compared to 76 (33.0%) by the FilmArray and 69 (30.3%) by the Luminex assay.
Clostridium difficile
(12.6 to 13.9% prevalence) and norovirus genogroup I (GI)/GII (5.7 to 13.9% prevalence) were two of the pathogens most commonly detected by both assays among prospective samples. Sapovirus was also commonly detected (5.7% positive rate) by the FilmArray assay. Among 270 additional previously characterized samples, both multiplex panels demonstrated high sensitivity (>90%) for the majority of targets, with the exception of several pathogens, notably
Aeromonas
sp. (23.8%) by FilmArray and
Yersinia enterocolitica
(48.1%) by the Luminex assay. Interestingly, the FilmArray and Luminex panels identified mixed infections in 21.1% and 13.0% of positive prospective samples, respectively, compared to only 8.3% by routine methods.