bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization and Micromilling of Flow Induced Aligned Carbon Nanotube Nanocomposites
Authors: Mahmoodi Mehdi , Mostofa M. G. , Jun Martin , Park Simon S.
Published: July 2013

Carbon nanotube (CNT) based polymeric composites exhibit high strength and thermal conductivity and can be electrically conductive at a low percolation threshold. CNT nanocomposites with polystyrene (PS) thermoplastic matrix were injection-molded and high shear stress in the flow direction enabled partial alignment of the CNTs. The samples with different CNT concentrations were prepared to study the effect of CNT concentration on the cutting behavior of the samples. Characterizations of CNT polymer composites were studied to relate different characteristics of materials such as thermal conductivity and mechanical properties to micromachining. Micro-end milling was performed to understand the material removal behavior of CNT nanocomposites. It was found that CNT alignment and concentrations influenced the cutting forces. The mechanistic micromilling force model was used to predict the cutting forces. The force model has been verified with the experimental milling forces. The machinability of the CNT nanocomposites was better than that of pure polymer due to the improved thermal conductivity and mechanical characteristics.
Fatigue Crack Propagation Analysis of Repaired Pipes With Composite Patch Under Cyclic Pressure
Authors: Ali Ghaffari Mir , Hosseini-Toudeshky Hossein
Published: July 2013

The pipes in offshore and marine structures are mainly made of low-strength structural steels such as A537 steel and are subjected to the effects of both corrosive medium and cyclic loading caused by many factors. Reinforcement and repair of components using composite patches can be used for piping to reduce the stress intensity factors at the crack-front of a corrosion fatigue crack. In this paper 3D finite element analyses in general mixed-mode fracture condition are performed to study the crack growth behavior of repaired pipes subjected to internal cyclic pressure. The required formulations, crack growth modeling, and remeshing are automatically handled by developing an ANSYS parametric design language (APDL) program. For this purpose an offshore pipe made of low-strength steel containing an initial fatigue corrosion crack repaired by glass/epoxy composite patch is considered. A parametric study will be performed to find the effects of patch thickness on fatigue crack growth life extension and crack-front shape of the repaired pipes.
Investigation of Physical and Chemical Delay Periods of Different Fuels in the Ignition Quality Tester
Authors: Zheng Ziliang , Badawy Tamer , Henein Naeim , Sattler Eric
Published: July 2013

This paper investigates the physical and chemical ignition delay (ID) periods in the constant volume combustion chamber of the Ignition Quality Tester (IQT). IQT was used to determine the derived cetane number (DCN) according to ASTM D6890-10a standards. The fuels tested were ultra low sulfur diesel (ULSD), jet propellant-8 (JP-8), and two synthetic fuels of Sasol IPK and F-T SPK (S-8). A comparison was made between the DCN and cetane number (CN) determined according to ASTM-D613 standards. Tests were conducted under steady state conditions at a constant pressure of 21 bars and various air temperatures ranging from 778 K to 848 K. The rate of heat release (RHR) was calculated from the measured pressure trace, and a detailed analysis of the RHR trace was made particularly for the auto-ignition process. Tests were conducted to determine the physical and chemical delay periods by comparing results obtained from two tests. In the first test, the fuel was injected into air according to ASTM standards. In the second test, the fuel was injected into nitrogen. The point at which the two resultant pressure traces separated was considered to be the end of the physical delay period. The effects of the charge temperature on the total ID as defined in ASTM D6890-10a standards, as well as on the physical and chemical delays, were determined. It was noticed that the physical delay represented a significant part of the total ID over all the air temperatures covered in this investigation. Arrhenius plots were developed to determine the apparent activation energy for each fuel using different IDs. The first was based on the total ID measured according to ASTM standards. The second was the chemical delay determined in this investigation. The activation energy calculated from the total ID showed higher values for lower CN fuels except Sasol IPK. The activation energy calculated from the chemical delay period showed consistency in the increase of the activation energy with the drop in CN including Sasol IPK. The difference between the two findings could be explained by examining the sensitivity of the physical delay period of different fuels to the change in air temperature.
Data Fusion Strategy for Multiscale Surface Measurements
Authors: Ramasamy Suresh K. , Raja Jayaraman , Boudreau Brian D.
Published: July 2013

Interdisciplinary research efforts have started focusing on the development of multiscale models and development of designer multiscale surfaces exhibiting specific properties at different scales for a specific purpose. With the rapid evolution of these new engineered surfaces for microelectromechanical systems (MEMS), microfluidics, etc., there is a strong need for developing tools to measure and characterize these surfaces at different scales. In order to obtain all meaningful details of the surface at various required scales, one is left with the only option of measuring the surface using multiple technologies using a combination of instruments. The majority of hardware-based approaches focus on the development of systems housing multiple technologies/capabilities into a single frame. These systems enable the user to obtain different surface maps using various technologies, but the user does not readily have the ability to combine all the obtained data into one single dataset. The effective approach toward multiscale measurement and characterization would be to use the individual measurement tools and finding a method to relate the individual coordinate systems and use an offline virtual tool to unify, manipulate, segment, merge, and retrieve data. Shape primitives and focus-based fusion strategies cannot be used as every data point in the data sets under consideration has to be treated as essentially at optimal focus. A multiscale data fusion strategy results in edge effects on nonplanar and high aspect ratio surfaces. An optimized fusion strategy, the “FWR method,” for the surface metrology domain is proposed where the subimages obtained from discrete wavelet frame (DWF) were separated into three regimes—form, waviness, and roughness—and fusion was not performed on subimages in the form regime. This approach effectively eliminates the edge effects. Individual data-point-level fusion was successfully demonstrated on Fresnel microlens array surface data as a case study of a nondirectional engineered surface with high aspect ratio.
Vortex Shedding in a Tandem Circular Cylinder System With a Yawed Downstream Cylinder
Authors: Wilkins Stephen J. , Hogan James D. , Hall Joseph W.
Published: July 2013

This investigation examines the flow produced by a tandem cylinder system with the downstream cylinder yawed to the mean flow direction. The yaw angle was varied from α=90deg (two parallel tandem cylinders) to α=60deg; this has the effect of varying the local spacing ratio between the cylinders. Fluctuating pressure and hot-wire measurements were used to determine the vortex-shedding frequencies and flow regimes produced by this previously uninvestigated flow. The results showed that the frequency and magnitude of the vortex shedding varies along the cylinder span depending on the local spacing ratio between the cylinders. In all cases the vortex-shedding frequency observed on the front cylinder had the same shedding frequency as the rear cylinder. In general, at small local spacing ratios the cylinders behaved as a single large body with the shear layers separating from the upstream cylinder and attaching on the downstream cylinder, this caused a correspondingly large, low frequency wake. At other positions where the local span of the tandem cylinder system was larger, small-scale vortices began to form in the gap between the cylinders, which in turn increased the vortex-shedding frequency. At the largest spacings, classical vortex shedding persisted in the gap formed between the cylinders, and both cylinders shed vortices as separate bodies with shedding frequencies typical of single cylinders. At certain local spacing ratios two distinct vortex-shedding frequencies occurred indicating that there was some overlap in these flow regimes.
Effects of Freestream Turbulence on the Characteristics in the Boundary Layer Near the Transition Onset Location
Authors: Patten Norah , Griffin Philip , Young Trevor M.
Published: July 2013

Experimental data is presented for a flat plate test facility with augmented levels of freestream turbulence (FST). The turbulence decay downstream of two turbulence generating grids, in addition to the integral length scales, is provided and good comparison with established correlations is presented. Boundary layer measurements using a single normal hotwire probe were obtained at FST intensities of 7%, 6%, 5.5%, 1.55%, and 1.45%, and the results presented include the fifth and 95th percentile of the velocity fluctuations and the root mean squared (RMS) velocity profiles near the transition onset region. The transition onset Reynolds number for each of the turbulence levels considered is consistent with theoretical findings. In all cases analyzed, the maximum fifth and 95th percentile far exceeded the maximum RMS values, with the location of the maximum 95th percentile closer to the wall compared to the maximum fifth percentile. Using probability density function (PDF) analysis, it is demonstrated that there is a dominating positive velocity fluctuation in the near-wall region and a dominating negative velocity fluctuation further out in the boundary layer and that the fluctuations in the boundary layer are greater compared to the freestream. The effect of the FST on the boundary layer is discussed with comparison to the Blasius solution and the influence of the fluctuations on the deviation from the Blasius profile is presented and discussed. Through investigation of the energy spectrum of the fluctuating velocity component within the boundary layer, it is shown that there is a higher energy content at lower frequency in the boundary layer when compared to that of the freestream.
Joule Heat Welding of Thin Platinum and Tungsten Wires and the Thermoelectric Effects Around Bi-Metal Junctions
Authors: Tohmyoh Hironori , Tanaka Tomochika , Fujimori Masato , Saka Masumi
Published: July 2013

Fine thermoelectric elements were fabricated on electrode chips by welding together the tips of thin 5 μm diameter Pt and W wires by Joule heat welding. The Pt/W junction was heated by bringing it into contact with a wire carrying a current, thus generating a voltage due to the Seebeck effect in the circuit containing the junction. The Pt/W junctions of two thermoelectric elements in separate circuits were brought into contact with each other. Current was supplied to one of the thermoelectric elements, while the temperature was measured using the other element as a thermocouple. The temperature, which is due to the Peltier effect, was found to depend on the direction of current supply.
Investigation of Dual Electrical Paths for Off-Chip Compliant Interconnects
Authors: Okereke Raphael , Kacker Karan , Sitaraman Suresh K.
Published: July 2013

This paper presents a study on a dual-path compliant interconnect design which attempts to improve the balance between mechanical compliance and electrical parasitics by using multiple electrical paths in place of a single electrical path. The high compliance of the parallel-path compliant interconnect structure will ensure the reliability of low-K dies. Implementation of this interconnect technology can be cost effective by using a wafer-level process and by eliminating the underfill process. Although an underfill is not required for thermomechanical reliability purposes, an underfill may be used for reducing contamination and oxidation of the interconnects and also to provide additional rigidity against mechanical loads. Therefore, this paper also examines the role of an underfill on the thermomechanical reliability of a dual-path compliant interconnect.
Interior and Edge Elastic Waves in Graphene
Authors: Liu P. , Zhang Y. W. , Gao H. J.
Published: July 2013

Elastic waves propagating in graphene nanoribbons were studied using both continuum modeling and molecular dynamics simulations. The Mindlin's plate model was employed to model the propagation of interior waves of graphene, and a continuum beam model was proposed to model the propagation of edge waves in graphene. The molecular dynamics results demonstrated that the interior longitudinal and transverse wave speeds of graphene are about 18,450 m/s and 5640 m/s, respectively, in good agreement with the Mindlin's plate model. The molecular dynamics simulations also revealed the existence of elastic edge waves, which may be described by the proposed continuum beam model.
Limitations of Pareto Front in Design Under Uncertainty and Their Reconciliation
Authors: Pandey Vijitashwa , Mourelatos Zissimos P. , Nikolaidis Efstratios
Published: July 2013

Engineering design reconciles design constraints with decision maker (DM) preferences. The task of eliciting and encoding decision maker preferences is, however, extremely difficult. A Pareto front representing the locus of the nondominated designs is, therefore, often generated to help a decision maker select the best design. In this paper, we show that this method has a shortcoming when there is uncertainty in both the decision problem variables and in the model of decision maker's preferences. In this case, the Pareto front is inconsistent with multi-attribute utility (MAU) theory, unless the decision maker trades off attributes or some functions of them linearly. This is a strong restriction. To account for this, we propose a methodology that enables a decision maker to select the best design on a modified pareto front (MPF) which is acquired using envelopes of a set of certainty equivalent (CE) surfaces. The proposed method does not require separability of the multi-attribute utility function into single-attribute utilities, nor does it require the decision maker to trade the attributes (or any function of them) linearly. We demonstrate our approach on a simple optimization problem and in design of a reduction gear.
Fabrication of Large Surface Area Semitransparent Monocrystalline Si Solar Cells
Authors: Makris Th. , Tsevas K. , Kadylis L. , Mprechas L. , Skuras E.
Published: July 2013

An experimental technique is presented for fabricating large surface area semitransparent monocrystalline Si solar cells. The semitransparency is achieved by laser-cutting two-dimensional periodic lattices of ellipses through industrially manufactured Si cells. A novel two-level metal base was invented for minimizing cell breakages during laser cutting. The periodic lattices consist of a large number of ellipses, so as to achieve uniform distribution of the transmitted solar radiation. High efficiencies over 13% are deduced from the I–V curves, recorded under physical sunlight, for all fabricated cells with a 5% transparency.
Two-Dimensional Nonlinear Analysis of an Untethered Spherical Buoy Due to Wave Loading
Authors: Ballard Zach , Mann Brian P.
Published: July 2013

The horizontal and vertical motions of a nonlinear spherical buoy, excited by synthetic ocean waves within a wave flume, is numerically and experimentally investigated. First, fluid motion in the wave tank is described using Airy's theory, and the forces on the buoy are determined using a modified form of Morison's equation. The system is then studied statically in order to determine the effects of varying system parameters. Numerical simulations then use the governing equations to compare predicted motions with experimentally observed behavior. Additionally, a commonly used linear formulation is shown to be insufficient in predicting buoy motion, while the nonlinear formulation presented is shown to be accurate.
Time-Fractional Camassa–Holm Equation: Formulation and Solution Using Variational Methods
Authors: Zhang Youwei
Published: July 2013

This paper presents the formulation of the time-fractional Camassa–Holm equation using the Euler–Lagrange variational technique in the Riemann–Liouville derivative sense and derives an approximate solitary wave solution. Our results witness that He's variational iteration method was a very efficient and powerful technique in finding the solution of the proposed equation.
Research on Ultrasonic Inspection of Cast Austenitic Stainless Steel Piping
Authors: Sakamoto Kazunobu , Furukawa Takashi , Komura Ichiro , Kamiyama Yoshinori , Mihara Tsuyoshi
Published: July 2013

Japan Nuclear Energy Safety Organization (JNES) has been carrying out the research program entitled “Nondestructive Inspection Technologies for the Cast Stainless Steel Piping” since 2009FY to comprehend the unique ultrasonic wave propagation in the Cast Austenitic Stainless Steel (CASS) and to confirm detection and sizing capability for cracks in the material by currently available ultrasonic testing techniques. The research is also intended to provide inspection staff with the fundamental information of ultrasonic wave propagation in CASS, for educational purpose.

In this research program, specimens whose material, size, dimension and welding method are identical to the main coolant piping system in Japanese pressurized water reactors (PWRs) are examined. Results from the study on the capability for inspection of CASS and the unique wave propagation phenomena such as beam skewing are discussed in this paper.
Design of Unpartitioned, Plug Type Header Boxes for Air-Cooled Heat Exchangers in Refinery Service
Authors: Nel Hugh-Jean , Nurick Alan , Nel André Leon , Lombaard Francois
Published: July 2013

Dry air-cooled heat exchangers (ACHE) form an integral part of refinery cooling systems of which the header boxes form an important component. It is commonly designed as an ASME Section VIII Division 1 pressure vessel, but unfortunately neither ASME nor the American Petroleum Institute (API) provide guidance regarding to the methodology which should be used in the assessment of nozzle loads on the header box design. Subsequently, the designer must rely either on empirical guidelines or Finite Element Analysis (FEA) in line with the requirements of ASME Section VIII U-2(g). The aim of this project therefore was to develop an analytical design methodology that accounts for the effects of these nozzle loads on the header box. A new mechanical model was derived by extending the existing ASME Section VIII rigid frame theory model and the result was tested against an FEA case study to determine whether the model was useable. It was found that the new model makes some useful qualitative statements but cannot be used for accurate stress analysis of the stresses near the base of the nozzle on the header box. The case study was also used to examine the effectiveness of a commonly used empirical guideline.
Fatigue Life of the Strain Hardened Austenitic Stainless Steel in Simulated PWR Primary Water
Authors: Tsutsumi Kazuya , Huin Nicolas , Couvant Thierry , Henaff Gilbert , Mendez Jose , Chollet Denis
Published: July 2013

Over the last 20 years or so, many studies have revealed the deleterious effect of the environment on fatigue life of austenitic stainless steels in pressurized water reactor (PWR) primary water. The fatigue life correlation factor, so-called Fen, has been standardized to consider the effect on fatigue life evaluation. The formulations are function of strain rate and temperature due to their noticeable negative effect compared with other factors [1,2]. However, mechanism causing fatigue life reduction remains to be cleared.

As one of possible approaches to examine underlying mechanism of environmental effect, the authors focused on the effect of plastic strain, because it could lead microstructural evolution on the material. In addition, in the case of stress corrosion cracking (SCC), it is well known that the strain-hardening prior to exposure to the primary water can lead to remarkable increase of the susceptibility to cracking [3,4]. However, its effect on fatigue life has not explicitly been investigated yet.

The main effort in this study addressed the effect of the prior strain-hardening on low cycle fatigue life of 304L stainless steel (SS) exposed to the PWR primary water. A plate of 304LSS was strain hardened by cold rolling or tension prior to fatigue testing. The tests were performed under axial strain-controlled at 300 °C in primary water including B/Li and dissolved hydrogen, and in air. The effect on environmental fatigue life was investigated through a comparison of the Fen in experiments and in regulations, and also the effect on the fatigue limit defined at 106 cycles was discussed.
Prediction of Residual Stress in Multi-Pass Welded Joint Using Idealized Explicit FEM
Authors: Shibahara Masakazu , Itoh Shinsuke , Okada Takashi , Ikushima Kazuki , Nishikawa Satoru
Published: July 2013

Heavy thick steel plate is used for pipes and also ship structures, and multi-pass welding is usually adopted for the welding. Because of the heavy thickness, residual stress plays an important role, particularly in crack propagation. Implicit Finite Element Method (FEM) is often used as a welding analysis method to examine the residual stress of the welded plate, but it is not easily applied to multi-pass welding problems with tens of thousands of degrees of freedom, because of the huge computational time and memory consumption. Alternatively, it is possible to simulate the residual stress in shorter time with lower memory consumption by using Idealized Explicit Finite Element Method developed by the authors. Moreover, the computational time can be shortened by using Idealized Explicit FEM using a Graphics Processing Unit (GPU). In this research, Idealized Explicit FEM parallelized using a GPU is applied to the analysis of the residual stresses of the multi-pass welding joint of a pipe structure made of heavy thick steel plate.

As the result, the residual stress simulated by the Idealized Explicit FEM corresponds to the measured residual stress. Furthermore, it is found that the grouping method may affect to the residual stress distribution.
Elastic-Plastic Fatigue Evaluation of a Heavy Wall Nozzle Subject to Rapid Thermal Transients
Authors: Dewees David J. , Cooch S. Michael
Published: July 2013

This paper presents a case study highlighting the use of the elastic-plastic fatigue methods in ASME Section VIII, Division 2 in the design fatigue evaluation of a heavy wall nozzle. The nozzle is expected to undergo a variety of thermal cycles during its design life, some of which include a rapid heatup or cooldown. The elastic fatigue approach is used for the initial evaluation; however, the thermal stresses induced by the rapid transients result in the application of a significant fatigue penalty factor (Ke,k).

An elastic-plastic stress analysis is therefore used to provide a more appropriate evaluation of the fatigue penalty factor for this case. Both the Twice-Yield and cycle-by-cycle methods are used to calculate the fatigue penalty factor, and give very similar results.
Rapid Aggregation of Biofuel-Producing Algae by the Bacterium Bacillus sp. Strain RP1137
Authors: Powell Ryan J. , Hill Russell T.
Published: July 2013

Algal biofuels represent one of the most promising means of sustainably replacing liquid fuels. However, significant challenges remain before alga-based fuels become competitive with fossil fuels. One of the largest challenges is the ability to harvest the algae in an economical and low-energy manner. In this article, we describe the isolation of a bacterial strain,
Bacillus
sp. strain RP1137, which can rapidly aggregate several algae that are candidates for biofuel production, including a
Nannochloropsis
sp. This bacterium aggregates algae in a pH-dependent and reversible manner and retains its aggregation ability after paraformaldehyde fixation, opening the possibility for reuse of the cells. The optimal ratio of bacteria to algae is described, as is the robustness of aggregation at different salinities and temperatures. Aggregation is dependent on the presence of calcium or magnesium ions. The efficiency of aggregation of
Nannochloropsis oceanica
IMET1 is between 70 and 95% and is comparable to that obtained by other means of harvest; however, the rate of harvest is fast, with aggregates forming in 30 s.
Distinct Amino Acids of Histone H3 Control Secondary Metabolism in Aspergillus nidulans
Authors: Nützmann Hans-Wilhelm , Fischer Juliane , Scherlach Kirstin , Hertweck Christian , Brakhage Axel A.
Published: July 2013

Chromatin remodelling events play an important role in the secondary metabolism of filamentous fungi. Previously, we showed that a bacterium,
Streptomyces rapamycinicus
, is able to reprogram the histone-modifying Spt-Ada-Gcn5-acetyltransferase/ADA (SAGA/ADA) complex of the model fungus
Aspergillus nidulans
. Consequently, the histone H3 amino acids lysine 9 and lysine 14 at distinct secondary metabolism genes were specifically acetylated during the bacterial fungal interaction, which, furthermore, was associated with the activation of the otherwise silent orsellinic acid gene cluster. To investigate the importance of the histone modifications for distinct gene expression profiles in fungal secondary metabolism, we exchanged several amino acids of histone H3 of
A. nidulans
. These amino acids included lysine residues 9, 14, 18, and 23 as well as serine 10 and threonine 11. Lysine residues were replaced by arginine or glutamine residues, and serine/threonine residues were replaced by alanine. All generated mutant strains were viable, allowing direct analysis of the consequences of missing posttranslational histone modifications. In the mutant strains, major changes in the expression patterns at both the transcriptional and metabolite levels of the penicillin, sterigmatocystin, and orsellinic acid biosynthesis gene clusters were detected. These effects were due mainly to the substitution of the acetylatable lysine 14 of histone H3 and were enhanced in a lysine 14/lysine 9 double mutant of histone H3. Taken together, our findings show a causal linkage between the acetylation of lysine residue 14 of histone H3 and the transcription and product formation of secondary metabolite gene clusters.
Conservation and Distribution of the Benzalkonium Chloride Resistance Cassette
bcrABC
in Listeria monocytogenes
Authors: Dutta Vikrant , Elhanafi Driss , Kathariou Sophia
Published: July 2013

Analysis of a panel of 116
Listeria monocytogenes
strains of diverse serotypes and sources (clinical, environment of food processing plants, and food) revealed that all but one of the 71 benzalkonium chloride-resistant (BC
r
) isolates harbored
bcrABC
, previously identified on a large plasmid (pLM80) of the 1998-1999 hot dog outbreak strain H7858. In contrast,
bcrABC
was not detected among BC-susceptible (BC
s
) isolates. The
bcrABC
sequences were highly conserved among strains of different serotypes, but variability was noted in sequences flanking
bcrABC
. The majority of the BC
r
isolates had either the pLM80-type of organization of the
bcrABC
region or appeared to harbor
bcrABC
on the chromosome, adjacent to novel sequences. Transcription of
bcrABC
was induced by BC (10 μg/ml) in strains of different serotypes and diverse
bcrABC
region organization. These findings reveal widespread dissemination of
bcrABC
across BC
r
L. monocytogenes
strains regardless of serotype and source, while also suggesting possible mechanisms of
bcrABC
dissemination across
L. monocytogenes
genomes.
Moulting matters: the importance of understanding moulting cycles in bats when using fur for endogenous marker analysis
Authors: Fraser E.E. , Longstaffe F.J. , Fenton M.B.
Published: July 2013

Endogenous markers are a valuable indicator of individual animal ecology, but data interpretation requires a detailed understanding of the timing of tissue formation. Fur is commonly used in bat research using endogenous markers, but the moulting cycles of most bat species are not well documented. In this review, we (i) describe methods of investigating bat moulting; (ii) summarize the current literature on bat moulting cycles, highlighting broad trends; (iii) discuss knowledge gaps; and (iv) make recommendations for optimal fur sampling protocols. Three characteristics may indicate moulting in bats: changing skin pigmentation; visible fur growth and colour changes; and endogenous markers. Most studies reported new fur growth once annually during summer–fall, although there were exceptions. The timing of new fur growth varies among species, sexes, and age classes. Individuals commonly experience asynchronous new fur growth, with dorsal fur growth occurring before ventral. Specific moult progressions vary among species. Knowledge gaps include moulting cycles in tropical species and in subadult and yearling bats; migration during new fur growth; and the timing of fur growth compared with shedding. We recommend that fur samples taken dorsally from adult males are the most likely to be representative of the bat’s site of summer residency.
WHICH ALTERNATING AND SYMMETRIC GROUPS ARE UNIT GROUPS?
Authors: DAVIS CHRISTOPHER , OCCHIPINTI TOMMY
Published: July 2013

We prove there is no ring with unit group isomorphic to Sn for n ≥ 5 and that there is no ring with unit group isomorphic to An for n ≥ 5, n ≠ 8. To prove the non-existence of such a ring, we prove the non-existence of a certain ideal in the group algebra 𝔽2[G], with G an alternating or symmetric group as above. We also give examples of rings with unit groups isomorphic to S1, S2, S3, S4, A1, A2, A3, A4, and A8. Most of our existence results are well-known, and we recall them only briefly; however, we expect the construction of a ring with unit group isomorphic to S4 to be new, and so we treat it in detail.
EXPLORING THE LINK BETWEEN KNOWLEDGE SHARING ENABLERS, INNOVATION CAPABILITY AND INNOVATION PERFORMANCE
Authors: YEŞIL SALIH , BÜYÜKBEŞE TUBA , KOSKA ALAEDDIN
Published: July 2013

The intense global competition, rapid technological changes, and higher consumer demands along with increasing uncertainty and risk; all threaten the life of the companies and force them to be more creative and innovative. Thus, business world needs innovative ideas more than ever. Hence, companies struggle to increase their innovative capacities in order to be more competitive. At the same time, performing innovation is not an easy task, it is a process that requires tremendous effort and changes in several parts of business.

The number of studies on innovation has increased. Different aspects of innovation from theoretical and practical points of views have been studied so far. This study aims to investigate the effect of knowledge sharing enablers on innovation capability along with the relationship between innovation capability and innovation performance. The findings from the research revealed that some of the components of knowledge sharing enablers have positive effect on the innovation capability, while others have not. Also, remarkable findings on significant positive affect of innovation capability on innovation performance were obtained.
Late Eocene Glaciofluvial to Glaciomarine transition in the Lambert Graben: constraints from lithofacies and mineralogy of ODP Site 1166 sediments, Prydz Bay, Antarctica
Authors: Strand K. , Köykkä J. , Lamminen J.
Published: July 2013

The transition from a glaciofluvial to a glacial sedimentary environment contains critical information for evaluating the onset of glaciation and early glacial dynamics in Antarctica. This study presents investigations of a sediment core from Ocean Drilling Program Leg 188, Site 1166, on the continental shelf in Prydz Bay, in order to provide evidence for the first occurrence of late Eocene glaciers in the Lambert Graben, East Antarctica. The Lambert Graben is a large fault-bounded structure, at least 700 km long and 100 km wide, and presently hosts the Lambert Glacier–Amery Ice Shelf system. The core consists of middle Eocene glacially influenced alluvial plain sediments,
c
. 110 m in total thickness that are overlain by a
c
. 20 m-thick early Oligocene glaciomarine succession. The upper contact is a major unconformity. Grain-surface microtextures, such as fractured plates and a relatively high content of ilmenite in alluvial outwash-plain sediments, indicate mixed northern and southern Prince Charles Mountains provenance and initiation of glaciers as early as middle Eocene time. Distribution of the major heavy minerals indicates a change to garnet-rich granulite terrain in sediment-supply during later ice-sheet evolution, when a lack of detritus from the southern Prince Charles Mountains becomes apparent. Glacier advance was no longer restricted to the Lambert Graben and the drainage area became wider. Good preservation of these low-stand glaciofluvial outwash-plain deposits was related to regional subsidence that progressed to a marine transgression and glaciomarine deposition when ice was able to advance to the continental shelf edge.
Local NOS inhibition impairs vascular and metabolic actions of insulin in rat hindleg muscle in vivo
Authors: Bradley Eloise A. , Richards Stephen M. , Keske Michelle A. , Rattigan Stephen
Published: July 2013

Insulin stimulates microvascular recruitment in skeletal muscle, and this vascular action augments muscle glucose disposal by ∼40%. The aim of the current study was to determine the contribution of local nitric oxide synthase (NOS) to the vascular actions of insulin in muscle. Hooded Wistar rats were infused with the NOS inhibitor Nω-nitro-l-arginine methylester (l-NAME, 10 μM) retrogradely via the epigastric artery in one leg during a systemic hyperinsulinemic-euglycemic clamp (3 mU·min−1·kg−1 × 60 min) or saline infusion. Femoral artery blood flow, microvascular blood flow (assessed from 1-methylxanthine metabolism), and muscle glucose uptake (2-deoxyglucose uptake) were measured in both legs. Local l-NAME infusion did not have any systemic actions on blood pressure or heart rate. Local l-NAME blocked insulin-stimulated changes in femoral artery blood flow (84%, P < 0.05) and microvascular recruitment (98%, P < 0.05), and partially blocked insulin-mediated glucose uptake in muscle (reduced by 34%, P < 0.05). l-NAME alone did not have any metabolic effects in the hindleg. We conclude that insulin-mediated microvascular recruitment is dependent on local activation of NOS in muscle and that this action is important for insulin's metabolic actions.
Assessment of wasted myocardial work: a novel method to quantify energy loss due to uncoordinated left ventricular contractions
Authors: Russell Kristoffer , Eriksen Morten , Aaberge Lars , Wilhelmsen Nils , Skulstad Helge , Gjesdal Ola , Edvardsen Thor , Smiseth Otto A.
Published: July 2013

Left ventricular (LV) dyssynchrony reduces myocardial efficiency because work performed by one segment is wasted by stretching other segments. In the present study, we introduce a novel noninvasive clinical method that quantifies wasted energy as the ratio between work consumed during segmental lengthening (wasted work) divided by work during segmental shortening. The wasted work ratio (WWR) principle was studied in 6 anesthetized dogs with left bundle branch block (LBBB) and in 28 patients with cardiomyopathy, including 12 patients with LBBB and 10 patients with cardiac resynchronization therapy. Twenty healthy individuals served as controls. Myocardial strain was measured by speckle tracking echocardiography, and LV pressure (LVP) was measured by micromanometer and a previously validated noninvasive method. Segmental work was calculated by multiplying strain rate and LVP to get instantaneous power, which was integrated to give work as a function of time. A global WWR was also calculated. In dogs, WWR by estimated LVP and strain showed a strong correlation ( r = 0.94) and good agreement with WWR by the LV micromanometer and myocardial segment length by sonomicrometry. In patients, noninvasive WWR showed a strong correlation ( r = 0.96) and good agreement with WWR using the LV micromanometer. Global WWR was 0.09 ± 0.03 in healthy control subjects, 0.36 ± 0.16 in patients with LBBB, and 0.21 ± 0.09 in cardiomyopathy patients without LBBB. Cardiac resynchronization therapy reduced global WWR from 0.36 ± 0.16 to 0.17 ± 0.07 ( P < 0.001). In conclusion, energy loss due to incoordinated contractions can be quantified noninvasively as the LV WWR. This method may be applied to evaluate the mechanical impact of dyssynchrony.
Does the Admission Blood Pressure Associate with Short- and Long Term Outcome in Stroke Patients Treated with Thrombolysis? A Single Centre Study
Authors: Bentsen L. , Ovesen C. , Christensen A. F. , Christensen H.
Published: July 2013

Background. The association between outcome and elevated admission blood pressure (BP) remains uncertain in acute stroke patients. The aim of the present study was to examine the association between admission blood pressure and outcome in ischemic stroke patients treated with tissue plasminogen activator (tPA).Method. This study included patients treated with tPA within 4.5 hours after symptom onset. Four quartiles based on the admission BP values were defined. BP development of the first 12 hours was compared to outcome parameters defined as NIHSS 24 hours after tPA and mRS after 3 months.Results. 265 patients were included. A trend with worse short- and long-term outcome was present in the quartiles with the lowest and highest admission BP compared to the quartile with admission values at 140–160 mm Hg systolic. BP in quartile 1 was insignificantly decreased after 12 hours while the BP in quartiles 3 and 4 remained above recommended levels.Conclusion. Admission BP is associated with short- and long-term outcome after stroke. Low- or high-admission BP indicates cardiac comorbidity or preexisting hypertension, where close monitoring and further examinations are requested to prevent poorer outcome.
A New Approach for a Class of the Blasius Problem via a Transformation and Adomian’s Method
Authors: Ebaid Abdelhalim , Al-Armani Nwaf
Published: July 2013

The main feature of the boundary layer flow problems is the inclusion of the boundary conditions at infinity. Such boundary conditions cause difficulties for any of the series methods when applied to solve such problems. To the best of the authors’ knowledge, two procedures were used extensively in the past two decades to deal with the boundary conditions at infinity, either the Padé approximation or the direct numerical codes. However, an intensive work is needed to perform the calculations using the Padé technique. Regarding this point, a new idea is proposed in this paper. The idea is based on transforming the unbounded domain into a bounded one by the help of a transformation. Accordingly, the original differential equation is transformed into a singular differential equation with classical boundary conditions. The current approach is applied to solve a class of the Blasius problem and a special class of the Falkner-Skan problem via an improved version of Adomian’s method (Ebaid, 2011). In addition, the numerical results obtained by using the proposed technique are compared with the other published solutions, where good agreement has been achieved. The main characteristic of the present approach is the avoidance of the Padé approximation to deal with the infinity boundary conditions.
A Targeted Survey for Scrapie in Jos Plateau State, Nigeria
Authors: Nwankiti O. O. , Ikeh E. I. , Arowolo O. A. , Nwankiti A. J. , Odugbo M. O. , Seuberlich T.
Published: July 2013

Scrapie, a disease of sheep and goats with a progressive course and fatal outcome, has not been identified in Nigeria. Anecdotal scrapie reports by livestock workers abound. Livestock diseases like scrapie form huddles in livestock economics of countries. For 8 months we surveyed for scrapie targeting emergency/casualty slaughter sheep and goats in Jos, Nigeria. We clinically examined 510 sheep and 608 goats of local breeds, aged from 12 months to 5 years. In total 31 (5.10%) goats and no sheep were clinically suspicious for scrapie. Caudal brainstem tissues of suspect animals collected postmortem were analyzed for the disease specific form of the prion protein, PrPSc, using Bio-Rad’s TeSeE ELISA rapid test kit. No sample was positive for scrapie. Fluorescent antibody test for rabies and H&E staining on samples were carried out for differential diagnosis. These showed no pathological lesions indicative for neurological disease. While our findings do not exclude the presence of scrapie in Jos, we demonstrate that targeted sampling of small ruminants for neuroinfectious disease is feasible in developing countries, pointing to the possibility of implementing such a monitoring scheme in Nigeria to prevent economic losses in small ruminant livestock as scrapie caveats from endemic countries have shown.
Idiopathic Spontaneous Adrenal Hemorrhage in the Third Trimester of Pregnancy
Authors: Imga Narin Nasiroglu , Tutuncu Yasemin , Tuna Mazhar Muslum , Ayçıçek Doğan Berçem , Berker Dilek , Guler Serdar
Published: July 2013

Spontaneous adrenal hemorrhage (SAH) is seen in the absence of trauma or adrenal tumor in adrenal glands. The incidence of SAH has been reported from 0.14% to 1.1% and it usually involves the right gland. During pregnancy, idiopathic unilateral SAH has been reported rarely. We present a case which comes to emergency department with an acute abdominal pain and the test results showed spontaneous left SAH.
Network Analysis Identifies an HSP90-Central Hub Susceptible in Ovarian Cancer
Authors: Liu Hanqing , Xiao Fang , Serebriiskii Ilya G. , O'Brien Shane W. , Maglaty Marisa A. , Astsaturov Igor , Litwin Samuel , Martin Lainie P. , Proia David A. , Golemis Erica A. , Connolly Denise C.
Published: July 2013

Purpose: Epithelial ovarian cancer (EOC) is usually detected at an advanced stage and is frequently lethal. Although many patients respond to initial surgery and standard chemotherapy consisting of a platinum-based agent and a taxane, most experience recurrence and eventually treatment-resistant disease. Although there have been numerous efforts to apply protein-targeted agents in EOC, these studies have so far documented little efficacy. Our goal was to identify broadly susceptible signaling proteins or pathways in EOC.

Experimental Design: As a new approach, we conducted data-mining meta-analyses integrating results from multiple siRNA screens to identify gene targets that showed significant inhibition of cell growth. On the basis of this meta-analysis, we established that many genes with such activity were clients of the protein chaperone HSP90. We therefore assessed ganetespib, a clinically promising second-generation small-molecule HSP90 inhibitor, for activity against EOC, both as a single agent and in combination with cytotoxic and targeted therapeutic agents.

Results: Ganetespib significantly reduced cell growth, induced cell-cycle arrest and apoptosis in vitro, inhibited growth of orthotopic xenografts and spontaneous ovarian tumors in transgenic mice in vivo, and inhibited expression and activation of numerous proteins linked to EOC progression. Importantly, paclitaxel significantly potentiated ganetespib activity in cultured cells and tumors. Moreover, combined treatment of cells with ganetespib and siRNAs or small molecules inhibiting genes identified in the meta-analysis in several cases resulted in enhanced activity.

Conclusion: These results strongly support investigation of ganetespib, a single-targeted agent with effects on numerous proteins and pathways, in augmenting standard EOC therapies. Clin Cancer Res; 19(18); 5053–67. ©2013 AACR.
Making Sense of Differing Overdose Mortality: Contributions to Improved Understanding of European Patterns
Authors: Waal Helge , Gossop Michael
Published: July 2013

The European Monitoring Centre for Drugs and Drug Addiction, EMCDDA, publishes statistics for overdose deaths giving a European mean number, and ranking nations in a national ‘league table' for overdose deaths. The interpretation of differing national levels of mortality is more problematic and more complex than is usually recognised. Different systems are used to compile mortality data and this causes problems for cross-national comparisons. Addiction behaviour can only be properly understood within its specific social and environmental ecology. Risk factors for overdose, such as the type of drug consumed, and the route of administration, are known to differ across countries. This paper describes problems associated with ranking and suggests how mortality data might be used in high-level countries aiming at reduction in the number of overdose deaths.
Impact of Alcohol-Related Video Sequences on Functional MRI in Abstinent Alcoholics
Authors: Krienke Ute J. , Nikesch Florian , Spiegelhalder Kai , Hennig Jürgen , Olbrich Hans M. , Langosch Jens M.
Published: July 2013

The object of this study was the identification of brain areas that were significantly more connected than other regions with a previously identified reference region, the posterior cingulate cortex, during the presentation of visual cues in alcoholics. Alcohol-related and neutral video sequences were presented to 30 alcoholics who had been abstinent for at least 4 days. Participants underwent a psychometric assessment before and after the presentation of the video sequences. Functional MRI data were acquired. Psychophysiological interaction analyses were carried out. Participants reported a significant increase in craving and arousal after the presentation of alcohol-related video sequences. The simple contrast alcohol versus neutral was found not to be significantly different in the present study. The brain regions that were found to correlate significantly more with the posterior cingulate cortex under the alcohol-related condition were the inferior parietal lobe, the medial temporal lobe, the inferior frontal gyrus, the postcentral gyrus, and the precuneus. The involvement of these regions in processes of memory, self-control, and self-reflection with a particular focus on alcohol dependence and craving will be discussed.
Environmental and Genomic Factors as well as Interventions Influencing Smoking Cessation: A Systematic Review of Reviews and a Proposed Working Model
Authors: de Viron S. , Malats N. , Van der Heyden J. , Van Oyen H. , Brand A.
Published: July 2013

Background: Smoking behaviour is a major public health problem worldwide. Several sources have confirmed the implication of genomic factors in smoking behaviour. These factors interact both with environmental factors and interventions to develop a certain behaviour. Objectives: Describing the environmental and genomic factors as well as the interventions influencing smoking cessation (SC) and developing a working model incorporating the different factors influencing SC were our main objectives. Methods: Two systematic reviews were conducted using articles in English from the Cochrane library, PubMed and HuGENet from January 2000 to September 2012: (1) a systematic review of systematic reviews and meta-analyses and (2) a systematic review of original research for genomic factors. The proposed working model was developed by making use of previous models of SC and applying an iterative process of discussion and re-examination by the authors. Results: We confirmed the importance of the 4 main factors influencing SC: (1) environmental factors, (2) genomic factors, (3) gene-environment interactions, and (4) evidence-based interventions. The model demonstrates the complex network of factors influencing SC. Conclusion: The working model of SC proposed a global view of factors influencing SC, warranting future research in this area. Future testing of the model will consolidate the understanding of the different factors affecting SC and will help to improve interventions in this field.