bluuebunny/crossref_metadata_2025 huggingface dataset:
Mechanisms responsible for the altered cardiac repolarization dispersion in experimental hypothyroidism
Authors: Ferrer T. , Arín R. M. , Casis E. , Torres‐Jacome J. , Sanchez‐Chapula J. A. , Casis O.
Published: September 2011

Aims:  To identify the causes for the inhomogeneity of ventricular repolarization and increased QT dispersion in hypothyroid mice.

Methods:  We studied the effects of 5‐propyl‐2‐thiouracil‐induced hypothyroidism on the ECG, action potential (AP) and current density of the repolarizing potassium currents Ito,fast, Ito,slow, IK,slow and Iss in enzymatically isolated myocytes from three different regions of mouse heart: right ventricle (RV), epicardium of the left ventricle (Epi‐LV) and interventricular septum. K+ currents were recorded with the patch‐clamp technique. Membranes from isolated ventricular myocytes were extracted by centrifugation. Kv4.2, Kv4.3, KChIP and Na/Ca exchanger proteins were visualized by Western blot.

Results:  The frequency or conduction velocity was not changed by hypothyroidism, but QTc was prolonged. Neither resting membrane potential nor AP amplitude was modified. The action potential duration (APD)90 increased in the RV and Epi‐LV, but not in the septum. Hypothyroid status has no effect either on Ito,slow, Ik,slow or Iss in any of the regions analysed. However, Ito,fast was significantly reduced in the Epi‐LV and in the RV, whereas it was not altered in cells from the septum. Western blot analysis reveals a reduction in Kv4.2 and Kv4.3 protein levels in both the Epi‐LV and the RV and an increase in Na/Ca exchanger.

Conclusion:  From these results we suggest that the regional differences in APD lengthening, and thus in repolarization inhomogeneity, induced by experimental hypothyroidism are at least partially explained by the uneven decrease in Ito,fast and the differences in the relative contribution of the depolarization‐activated outward currents to the repolarization process.
α‐Synuclein Neuropathology is Controlled by Nuclear Hormone Receptors and Enhanced by Docosahexaenoic Acid in A Mouse Model for Parkinson's Disease
Authors: Yakunin Eugenia , Loeb Virginie , Kisos Haya , Biala Yoav , Yehuda Shlomo , Yaari Yoel , Selkoe Dennis J. , Sharon Ronit
Published: September 2011

α‐Synuclein (α‐Syn) is a neuronal protein that accumulates progressively in Parkinson's disease (PD) and related synucleinopathies. Attempting to identify cellular factors that affect α‐Syn neuropathology, we previously reported that polyunsaturated fatty acids (PUFAs) promote α‐Syn oligomerization and aggregation in cultured cells. We now report that docosahexaenoic acid (DHA), a 22:6 PUFA, affects α‐Syn oligomerization by activating retinoic X receptor (RXR) and peroxisome proliferator‐activated receptor γ2 (PPARγ2). In addition, we show that dietary changes in brain DHA levels affect α‐Syn cytopathology in mice transgenic for the PD‐causing A53T mutation in human α‐Syn. A diet enriched in DHA, an activating ligand of RXR, increased the accumulation of soluble and insoluble neuronal α‐Syn, neuritic injury and astrocytosis. Conversely, abnormal accumulations of α‐Syn and its deleterious effects were significantly attenuated by low dietary DHA levels. Our results suggest a role for activated RXR/PPARγ 2, obtained by elevated brain PUFA levels, in α‐Syn neuropathology.
Total Phenolic Content, Consumer Acceptance, and Instrumental Analysis of Bread Made with Grape Seed Flour
Authors: Hoye, Jr Clifford , Ross Carolyn F.
Published: September 2011

Abstract:  Grape seed flour (GSF) from grape pomace, a waste product generated during winemaking, was explored for use in bread production due to its potential health benefits. This study evaluated the consumer acceptance and physical properties of bread, including total phenolic content (TPC), made with varying levels of GSF. Dough and breads were prepared using different levels of replacement of hard red spring wheat flour (HRS) with GSF (0 to 10 g GSF/100 g HRS) and stored for 0, 2, or 6 wk at −20 °C. Replacement of 10 g GSF/100 g HRS increased the bread TPC from 0.064 mg tannic acid/g dry weight to 4.25 mg tannic acid/g dry weight. Consumer acceptance and instrumental analyses were used to investigate changes in sensory and texture properties due to GSF replacement. Replacement above 5 g GSF/100 g HRS decreased the loaf brightness and volume, with an increase in the bread hardness and porosity. Generally, breads containing ≥ 7.5 g GSF/100 g HRS were characterized by lower consumer acceptance. A reduction in overall and bitterness acceptance was observed in bread at 10 g GSF/100 g HRS, with decreased acceptance of astringency and sweetness at 7.5 and 10 g GSF/100 g HRS. Based on these results, the replacement of 5 g GSF/100 g HRS is recommended for the production of fortified breads with acceptable physical and sensory properties and high TPC activity compared to refined bread.

Practical Applications:  This study shows that grape seed flour (GSF) can be used to replace hard red spring wheat flour (HRS) in bread production, with moderate impact on the physical and sensory properties of the bread. Replacement of up to 10 g GSF/100 g HRS significantly decreased overall consumer acceptance of the bread, with lower consumer acceptance of sweetness and astringency at 7.5 and 10 g GSF/100 g HRS. Thus, a replacement value of 5 g GSF/100 g HRS is recommended for the production of fortified breads.
Association of Furosemide Dose With Clinical Status, Left Ventricular Dysfunction, Natriuretic Peptides, and Outcome in Clinically Stable Patients With Chronic Systolic Heart Failure
Authors: Dini Frank L. , Guglin Maya , Simioniuc Anca , Donati Francesca , Fontanive Paolo , Pieroni Andrea , Orsini Enrico , Caravelli Paolo , Marzilli Mario
Published: September 2011

In chronic heart failure (HF), high daily doses of furosemide have been associated with increased mortality. The authors sought to evaluate the relationships between orally administered furosemide doses, clinical status, left ventricular (LV) dysfunction, N‐terminal proBNP (NT‐proBNP), and outcome in 400 outpatients with chronic HF and LV ejection fraction (EF) ≤ 45%. Clinical status, NT‐proBNP levels, and estimated glomerular filtration rate (eGFR) were evaluated. Median follow‐up duration was 32 months. The median values of daily‐dose furosemide and of furosemide dose normalized to body surface area were 25 mg (12.5–62.5 mg) and 15 mg/m2 (13–34 mg/m2), respectively. A total of 32% of patients had decompensated HF according to Framingham score and criteria for congestion. In clinically stable patients, a multivariable Cox model, which included clinical and echocardiographic parameters plus NT‐proBNP, hemoglobin, and eGFR, showed that normalized furosemide dose ( P=.017), anemia (P=.060), age (P=.080), and New York Heart Association class (P=.080) were predictors of all cause‐mortality. In patients with decompensated HF, LV end‐systolic volume index (P=.018), NT‐proBNP (P=.060), and reduced eGFR (P=.070) were independently related to the outcome. Normalized furosemide dose was a major determinant of prognosis in patients with chronic HF but without ongoing signs and symptoms, and this suggests a possible negative interaction of this drug in clinically stable patients. ©2011 Wiley Periodicals, Inc.
Decisions about weight management: a synthesis of qualitative studies of obesity
Authors: Brown I. , Gould J.
Published: September 2011

There is a high non‐attendance and dropout attrition from weight management interventions for adults with obesity. Patient dissatisfaction with consultations involving decisions about interventions may be a factor. A systematic review was undertaken of qualitative studies reporting perceptions, experiences, contexts and influences for adults facing, or reflecting on, weight management. The aim was to synthesize a generic model of influences on decision‐making about weight management for adult patients. Electronic database and hand searches identified 29 qualitative studies involving 1387 participants (mean age 45.3 years; mean BMI 37.1 kg m−2; 79.9% women). Seven overarching themes were inductively derived from extracted data spanning: cultural identity; social structures such as gender; responses to obesity stigma; previous weight loss experiences; personal motivators and barriers; social support; and practical resources. A model is presented in the paper. Improving decisions about weight management requires attention to how diffuse cultural and psycho‐social factors, such as obesity stigma, influence patient choices. Reflection on experiences of previous attempts at weight loss is also essential, as are practical resource factors – particularly for less affluent groups. Considering these factors along with more established theories of individual psychological motivations and barriers may help to improve initial participation and retention within interventions.
Adenylate cyclase 1 promotes strengthening and experience‐dependent plasticity of whisker relay synapses in the thalamus
Authors: Wang Hao , Liu Hong , Storm Daniel R. , Zhang Zhong‐wei
Published: September 2011

Non‐technical summary  Cyclic AMP‐mediated signalling plays an important role in the development and plasticity of synaptic circuits, and adenylate cyclase 1 is a major enzyme for cyclic AMP production in the brain of newborns. We show that in mice deficient in adenylate cyclase 1, developmental strengthening and experience‐dependent plasticity of excitatory synapses are impaired, but developmental pruning of the synapses is not affected. These results increase our understanding of the processes by which neuronal circuits are formed and modified during development.
Prior endurance exercise prevents postprandial lipaemia‐induced increases in reactive oxygen species in circulating CD31+ cells
Authors: Jenkins Nathan T. , Landers Rian Q. , Thakkar Sunny R. , Fan Xiaoxuan , Brown Michael D. , Prior Steven J. , Spangenburg Espen E. , Hagberg James M.
Published: September 2011

Non‐Technical Summary  Circulating angiogenic cells (CACs) repair and maintain the vascular endothelium. CACs are responsive to lifestyle factors such as diet and physical activity. For example, their capacity to regenerate the endothelium is impaired in cardiovascular disease patients, whereas exercise training can improve CAC function. In this study, we examined the effects of a high‐fat meal with and without prior endurance exercise on several molecular aspects of CAC function, including levels of reactive oxygen species (ROS), nitric oxide (NO), intracellular lipids, and gene expression. Our results indicated that the high‐fat meal induced significant oxidative stress (i.e. ROS production) in the CACs that expressed the cell surface protein CD31. However, when subjects performed a single bout of exercise on the prior day, the meal had no effect on ROS in CD31+ cells. Therefore, we concluded that prior exercise prevents the oxidative stress induced by a high‐fat meal in CD31+ CACs.
Gap junctions and other mechanisms of cell–cell communication regulate basal insulin secretion in the pancreatic islet
Authors: Benninger R. K. P. , Head W. Steven , Zhang Min , Satin Leslie S. , Piston David W.
Published: September 2011

Non‐Technical Summary  The islet of Langerhans secretes the hormone insulin in response to elevated glucose. Interactions between cells within the islet is important for the regulation of insulin secretion, to both suppress basal insulin secretion and enhance the glucose‐stimulated response. We show that multiple mechanisms of cell–cell communication are required for the suppression of basal insulin release. First, gap junctions suppress spontaneous calcium signals which suppresses triggering of insulin release. Second, other juxtacrine mechanisms, regulated by cAMP and glucose, suppress more distal steps in the regulation of insulin granule exocytosis. Each mechanism is sufficiently robust to compensate for a loss of the other and still fully suppress basal insulin release. This new insight into the function of islet of Langerhans is important for understanding the development and treatment of diabetes.
Modeling
of Thermally Driven Resonance at Multiscales
Authors: Srinivasan P. , Mark
Spearing S.
Published: September 2011

Understanding the mechanisms of thermally driven resonance is a key for designing many engineering and physical systems especially at small scales. This paper focuses on the modeling aspects of such phenomena using the classical Fourier diffusion theory. Critical analysis revealed that the thermally induced resonant excitation is characterized by the generation of multiple wave trains with a constant phase shift as opposed to the single standing wave generated in a mechanically driven resonant response. The hypothesis proposed herein, underpin a broad range of scientific and technological developments and the analytical treatment enables design of thermally driven resonant systems with improved performance.
Five-Axis CNC Tool Grinding: Part I—Rake Face Grinding
Authors: Rababah Mahmoud M. , Chen Zezhong C.
Published: September 2011

Grinding the helical surfaces in end-mill cutters using two-axis CNC machines is well investigated in literature. However, the grinding wheels do not have explicit geometric representations and the produced helical angles differ from the designed values. Moreover, to the best knowledge of the authors, no reliable and robust algorithm exists to grind generic shape cutters with constant normal rake angles. Thus, the first part of this work introduces a five-axis grinding process that keeps the normal rake angle constant along the rake face. The parameters that affect the shape of the tool flutes are also analyzed and studied in this part. These parameters are then optimized in the second part to obtain optimum wheel shapes grinding the tool flutes along optimum paths. Overall, the grinding process proposed grinds the tool flutes with close matching to the designed ones and replaces the complex wheel shapes commonly used by simple prismatic ones.
Fatigue Behavior, Bridging Stresses, and Fatigue Reliability in Silicon Nitride Ceramics
Authors: Greene Rawley B. , Kruzic Jamie J.
Published: September 2011

Silicon nitride ceramics doped with rare-earth oxides exhibit excellent hardness, toughness, and strength at elevated temperatures making them attractive materials for replacing cemented carbides in a variety of manufacturing applications such as cutting and rolling tools. One recent example is the application of rolling of high strength alloy wires from steels and nickel-based super-alloys where cemented carbide rolls suffer wear and thermal fatigue cracking, leading to a degradation of wire quality. [1] Furthermore, it has been shown that under moderate loading silicon nitride rolls can give >10 times longer life and improved wire surface quality. [1] However, it has also been shown that the rolls can suffer fatigue failure at higher loadings, for example when rolling wires with high deformation resistance such as the super alloy wire Nicrofer S7020. [1–2] Accordingly the aim of this study is the develop a design tool for predicting the fatigue failure of silicon nitride ceramics. The silicon nitrides with favorable mechanical properties have microstructures with elongated β-phase grains and a glassy intergranular film. The weak film encourages intergranular fracture allowing the formation of grain bridges across the crack wake which helps to reduce the stress intensity felt at the crack tip, Ktip. [3]
Energy Consumption Reduction for Sustainable Manufacturing Systems Considering Machines With Multiple-Power States
Authors: Sun Zeyi , Biller Stephan , Gu Fangming , Li Lin
Published: September 2011

Due to rapid consumption of world’s fossil fuel resources and impracticality of large-scale application and production of renewable energy, the significance of energy efficiency improvement of current available energy modes has been widely realized by both industry and academia. A great deal of research has been implemented to identify, model, estimate, and optimize energy efficiency of single-machine manufacturing system [1–5], but very little work has been done towards achieving the optimal energy efficiency for a typical manufacturing system with multiple machines. In this paper, we analyze the opportunity of energy saving on the system level and propose a new approach to improve energy efficiency for sustainable production systems considering the fact that more and more modern machines have multiple power states. Numerical case based on simulation model of an automotive assembly line is used to illustrate the effectiveness of the proposed approach.
On Some Eco-Indicators of Cutting Tools
Authors: Ullah A. M. M. Sharif , Kitajima Koichi , Akamatsu Takeshi , Furuno Masahiro , Tamaki Jun’ichi , Kubo Akihiko
Published: September 2011

This study deals with some eco-indicators of cutting tools. Eco-indicators of cutting tools are classified into three categories, namely, material-, process-, and geometry-related eco-indicators. Material-related eco-indicators consist of density, price, embodied energy, CO2 footprint, NOX, SOX, water usage, material processing energy, and recycle fraction of tool materials. Process-related eco-indicators consist of material removal rate, cutting velocity, feed rate, spindle speed, and surface coating. Geometry-related eco-indictors consist of special geometric features of cutting tool that make the tool’s performance robust in terms of process-related eco-indicators. The general definitions and representations of these indicators are described. Giving examples of cutting tools made of tungsten carbide and HSS, it is shown that further research is needed to develop an ideal cutting tool that is equally preferable in terms of material-, process-, and geometry-related eco-indicators.
Determination of Minimum Blankholding Pressure for Producing Wrinkle Free Products in Multistage Deep Drawing
Authors: Agrawal Anupam , Reddy N. Venkata , Dixit P. M.
Published: September 2011

Wrinkling in the flange region has been observed during redrawing operation by few researchers. In the present work an analysis methodology, based on a combination of upper bound and energy approaches, is proposed for the prediction of number of wrinkles and minimum blankholding pressure necessary to avoid wrinkling in redrawing operation. Thickness variation predicted by the upper bound formulation is used as input for the wrinkling analysis by assuming a suitable waveform based on geometrical and process conditions. The flange is constrained at both the ends, i.e. by the blank holder profile radius and at the die entry point (where the sheet enters into the die cavity). The waveform for present analysis is assumed such that it has zero displacement at both the ends (since it is constrained) and the maximum amplitude of the wave at some point in between those ends. The wrinkling predicted by the present methodology seems to be reasonably accurate considering the geometrical and process constraints of the redraw.
Alternative Shop-Floor Re-Layout Design due to Dynamic Operation Changes
Authors: Wang Lihui
Published: September 2011

The turbulent environment of dynamic job-shop operations affects shop-floor layout as well as manufacturing operations. Due to the dynamic nature of shop-floor layout changes, essential requirements such as adaptability and responsiveness to the changes need to be considered in addition to the cost issues for material handling and machine relocation when reconfiguring a shop floor’s layout. Here, based on the source of uncertainty, the shop floor layout problem is split into two sub-problems and dealt with by two modules: re-layout and find-route. Genetic algorithm is used where changes may cause a re-layout of the entire shop, while function blocks are utilised to find the best sequence of robots for the new conditions within the existing layout. This paper reports the latest development to the author’s previous work.
A Comparative Study of Carbide Tools in Drilling of CFRP and CFRP-Ti Stacks
Authors: Beal Aaron , Kim Dave Dae-Wook , Park Kyung-Hee , Kwon Patrick
Published: September 2011

A comparative study was conducted to investigate drilling of a titanium (Ti) plate stacked on a carbon fiber reinforced plastic panel. The effects on tool wear and hole quality in drilling using micrograin tungsten carbide (WC) tools were analyzed. The experiments were designed to first drill CFRP alone to create 20 holes. Then CFRP-Ti stacks were drilled for the next 20 holes with the same drill bit. This process was repeated until drill failure. The drilling was done with tungsten carbide (WC) twist drills at two different speeds (high and low). The feed rate was kept the same for each test, but differs for each material drilled. A Scanning Electron Microscope (SEM), and a Confocal Laser Scanning Microscope (CLSM), were used for tool wear analysis. Hole size and profile, surface roughness, and Ti burrs were analyzed using a coordinate measuring system, profilometer, and an optical microscope with a digital measuring device. The experimental results indicate that the Ti drilling accelerated WC flank wear while CFRP drilling deteriorated the cutting edge. Entry delamination, hole diameter errors, and surface roughness of the CFRP plate became more pronounced during drilling of CFRP-Ti stacks, when compared with the results from CFRP only drilling. Damage to CFRP holes during CFRP-Ti stack drilling may be caused by Ti chips, Ti adhesion on the tool outer edge, and increased instability as the drill bits wear.
Size Reduction of Cellulosic Biomass in Biofuel Manufacturing: Effects of Milling Orientation on Sugar Yield
Authors: Zhang Meng , Song Xiaoxu , Zhang P. F. , Zhang Q. , Pei Z. J. , Deines T. , Wang D. H.
Published: September 2011

Cellulosic biofuels can reduce greenhouse gas emissions and the nation’s dependence on foreign oil. In order to convert cellulosic biomass into biofuels, size reduction of biomass is a necessary step. Most related studies in the literature claimed that smaller particles produced higher sugar yields. However, some researchers reported that this claim was not always true. The literature does not have satisfactory explanations for the inconsistence. This paper presents an experimental study on size reduction of poplar wood using a metal cutting process (milling). The results provided one explanation for this inconsistence. It was found for the first time that milling orientation had a strong effect on poplar wood sugar yield. Although smaller poplar particles had a higher sugar yield when they were milled from the same orientation, this trend did not exist for particles milled from different orientations.
Experimental Study of High-Frequency Vibration Assisted Micro/Meso-Scale Forming of Metallic Materials
Authors: Yao Zhehe , Kim Gap-Yong , Faidley LeAnn , Zou Qingze , Mei Deqing , Chen Zichen
Published: September 2011

Micro/meso-scale forming is a promising technology for mass production of miniature metallic parts. However, fabrication of micro/meso-scale features leads to challenges due to the friction increase at the interface and tool wear from highly localized stress. In this study, the use of high-frequency vibration for potential application in the technology of micro/meso-scale forming has been investigated. A versatile experimental setup based on a magnetostrictive (Terfenol-D) actuator was built. Vibration assisted micro/meso-scale upsetting, pin extrusion and cup extrusion were conducted to understand the effects of workpiece size, excitation frequency and the contact condition. Results showed a change in load reduction behavior that was dependent on the excitation frequency and contact condition. The load reduction can be explained by a combination of stress superposition and friction reduction. It was found that a higher excitation frequency and a less complicated die-specimen interface were more likely to result in a friction reduction by high-frequency vibration.
Fabrication of Conformal Ultrasound Transducer Arrays and Horns Based on Multi-Axis CNC Accumulation
Authors: Pan Yayue , Zhou Chi , Chen Yong , Partanen Jouni P.
Published: September 2011

Ultrasonic imaging is an important medical imaging technique. It uses ultrasound over 20K Hz to detect and visualize muscles, tendons, and many internal organs. Previous studies have shown that an improved acoustic performance can be achieved by conformal ultrasound transducer arrays and horns that can wrap conformably around curved surfaces. To address challenges in fabricating such curved ultrasound transducer arrays and horns, we investigate the possibility of using a newly developed additive manufacturing (AM) process named CNC accumulation. In such an AM process, an accumulation tool can have multi-axis motion, which is beneficial for building conformal ultrasound transducer arrays and horns on a curved surface. To address different resolution requirements, we illustrate the use of multiple accumulation tools that can have different curing sizes and power in the fabrication of a single component. The tool path planning methods for any given cylindrical and spherical surfaces have been discussed. Based on the developed prototype system, various test cases have been performed. The experimental results have illustrated the capability of the process and its potential use in the fabrication of conformal ultrasound transducer arrays and horns. The current limitations and future development have also been discussed.
Effect of Machining Parameters on Surface Roughness in Vibration-Assisted Grinding
Authors: Li Kuan-Ming , Hu Yang-Ming , Yang Zhong-Yi , Chen Ming-Yuan , Hsu Fu-Chuan
Published: September 2011

Dry machining is considered as a green manufacturing process because the use of cutting fluids has concerns about environmental contamination and health hazards. However, in grinding, the use of cutting fluids is a common strategy to improve the cutting performance and the product surface finish due to the transportation of heat away from the cutting zone. Vibration-assisted machining is a novel technology which is an efficient technique for high quality surface finish in dry cutting. The purpose of this paper is to investigate the feasibility of vibration-assisted grinding of SKD61 steels, where the amplitude about 1 μm with a frequency about 10 KHz is applied. This study compares the machined surface finish in vibration-assisted grinding to that in conventional machining based on experimental measurements. The effects of the grinding and vibrating conditions on the ground surface finish are studied. A near mirror surface (Ra = 0.05 μm) is achieved at the vibration frequency of 11.4 KHz in this paper. It is also found that the best surface finish in vibration-assisted grinding is affected both by the feed and the vibration frequencies. The experimental results show that proper combination of grinding and vibration parameters should be carefully chosen to prevent instability in grinding.
Investigation of Strain Gradients and Magnitudes During Microbending
Authors: Wang Lijie , Kinsey Brad L. , Korkolis Yannis
Published: September 2011

Sheet metal forming of parts with microscale dimensions is gaining importance due to the current trend towards miniaturization, especially in the electronics industry. In microforming, although the process dimensions are scaled down, the polycrystalline material stays the same (e.g., the grain size remains constant). When the specimen feature size approaches the grain size, the properties of individual grains begin to affect the overall deformation behavior. This results in inhomogeneous deformation and increased data scatter of the process parameters. In this research, the influence of the specimen size and the grain size on the distribution of plastic deformation through the thickness during a 3-point microbending process is investigated via digital image correlation. Results showed that with miniaturization, a decrease in the strain gradient existed which matched previous research with respect to micro-hardness measurement.
Microvia Formation for Multi-Layer PWB by Laser Direct Drilling: Improvement of Hole Quality by Silica Fillers in Build-Up Layer
Authors: Ogawa Keiji , Hirogaki Toshiki , Aoyama Eiichi , Obata Kuniyoshi , Ayuzawa Tsukasa
Published: September 2011

Microvia formation technology using lasers has become the dominant method for drilling microvia called blind via-holes (BVHs) in printed wiring boards (PWBs). Laser direct drilling (LDD), drilling directly outer copper foil by laser, has attracted attention as a novel method. In particular, when copper and resin with different processing thresholds are drilled at the same time, an overhang defect occurs on the drilled hole. However, the overhang generation mechanism has not been clarified. Therefore, we investigated it by detailed observation of the drilled-hole section. Moreover, the overhang length was estimated using the finite element method (FEM). Influences of surface treatment of outer copper foil and thermal properties of the build-up layer were evaluated experimentally and analytically. Consequently, an experiment with a prototype PWB with silica filler added in the build-up layer was carried out. Using the prototype PWBs, the overhang was reduced as shown in FEM analysis results.
Plant Layout Optimization Considering the Effect of Maintenance
Authors: Lee Seungchul , Brzezinski Adam , Ni Jun
Published: September 2011

With increasing production costs and constraints, demand has increased for manufacturers to minimize maintenance cost and product transport time. We address some aspects of this problem by examining how to choose the optimal layout of stations (machines or buffers) in a production facility based on how the station layout affects the maintenance and product transport times. Specifically, we consider how the location of the stations relative to the maintenance facility affects the overall maintenance time as well as how the location of the final station affects the product transport time. Hence, we can address maintenance cost during the design-phase of a production facility. By employing discrete-design optimization techniques, we generate and evaluate various station layouts to choose an optimal layout which satisfies all geometric and adjacency constraints. We focus on a single, serial production line including a set of n stations.
Size Effects in Cutting With a Diamond-Coated Tool
Authors: Qin Feng , Gong Xibing , Chou Kevin
Published: September 2011

In machining using a diamond-coated tool, the tool geometry and process parameters have compound effects on the thermal and mechanical states in the tools. For example, decreasing the edge radius tends to increase deposition-induced residual stresses at the tool edge interface. Moreover, changing the uncut chip thickness to a small-value range, comparable or smaller than the edge radius, will involve the so-called size effect. In this study, a developed 2D cutting simulation that incorporates deposition residual stresses was applied to evaluate the size effect, at different cutting speeds, on the tool stresses, tool temperatures, specific cutting energy as well as the interface stresses around a cutting edge. The size effect on the radial normal stress is more noticeable at a low speed. In particular, a large uncut chip thickness has a substantially lower stress. On the other hand, the size effect on the circumferential normal stress is more noticeable at a high speed. At a small uncut chip thickness, the stress is largely compressive.
Theoretical and Numerical Analysis of Incremental Sheet Forming by Using High Pressure Water Jet
Authors: Lu B. , Cao J. , Ou H.
Published: September 2011

Incremental sheet forming using water jet (ISF-WJ) is a new sheet metal forming process proposed in recent years. Few reports can be found on this process and some basic questions are unanswered, i.e., the water jet pressure required for plastic forming and the accuracy of this forming process. In this paper, an analytical model was developed to evaluate the size effect in the ISF-WJ process with respect to some key parameters, such as sheet thickness, part dimension, jet size and jet pressure. Three commonly used engineering sheet materials (aluminum, stainless steel and titanium) are studied in the analysis and the formability of water jet on these materials was evaluated. In addition, comparisons are made between the ISF-WJ and conventional ISF process with rigid tool based on finite element simulations. The result suggests that the dimensional accuracy of ISF-WJ may be controlled by a supporting back plate and ISF-WJ shows a better distribution of strain and thickness reduction than ISF process. It also provides a good reference for future ISF-WJ equipment design and development.
The Effect of Nanoparticles on the Processing and Properties of Aluminum Nitride by Powder Injection Molding
Authors: Onbattuvelli Valmikanathan P. , Atre Sundar V. , McCabe Timothy , Laddha Sachin
Published: September 2011

Aluminum nitride (AlN) exhibits many functional properties that are relevant to applications in electronics, aerospace, defense and automotive industries. However, the successful translation of these properties into final applications lies in the net-shaping of ceramics into fully dense microstructures. Increasing the packing density of the starting powders is one effective route to achieve high sintered density and dimensional precision. The present paper presents an in-depth study on the effects of nanoparticle addition on the powder injection molding process (PIM) of AlN powder-polymer mixtures. In particular, bimodal mixtures of nanoscale and sub-micrometer particles were found to have significantly increased powder packing characteristics (solids loading) in the powder-polymer mixtures. The influence of nanoparticle addition on the multi-step PIM process was examined. The above results provide new perspectives which could impact a wide range of materials, powder processing techniques and applications.
Influence of Continuous Direct Current on the Micro Tube Hydroforming Process
Authors: Wagner Scott W. , Ng Kenny , Emblom William J. , Camelio Jaime A.
Published: September 2011

Research of the micro tube hydroforming (MTHF) process is being investigated for potential medical and fuel cell applications. This is largely due to the fact that at the macro scale the tube hydroforming (THF) process, like most metal forming processes has realized many advantages. Unfortunately, large forces and high pressures are required to form the parts so there is a large potential to create failed or defective parts. Electrically Assisted Manufacturing (EAM) and Electrically Assisted Forming (EAF) are processes that apply an electrical current to metal forming operations. The intent of both EAM and EAF is to use this applied electrical current to lower the metals required deformation energy and increase the metal’s formability. These tests have allowed the metals to be formed further than conventional methods without sacrificing strength or ductility. Currently, various metal forming processes have been investigated at the macro scale. These tests also used a variety of materials and have provided encouraging results. However, to date, there has not been any research conducted that documents the effects of applying Electrically Assisted Manufacturing (EAM) techniques to either the tube hydroforming process (THF) or the micro tube hydroforming process (MTHF). This study shows the effects of applying a continuous direct current to the MTHF process.
Molecular Dynamics Simulation of AFM-Based Nanomachining Processes
Authors: Promyoo Rapeepan , El-Mounayri Hazim , Varahramyan Kody , Martini Ashlie
Published: September 2011

Recently, atomic force microscopy (AFM) has been widely used for nanomachining and fabrication of micro/ nanodevices. This paper describes the development and validation of computational models for AFM-based nanomachining (nanoindentation and nanoscratching). The Molecular Dynamics (MD) technique is used to model and simulate mechanical indentation and scratching at the nanoscale in the case of gold and silicon. The simulation allows for the prediction of indentation forces and the friction force at the interface between an indenter and a substrate. The effects of tip curvature and speed on indentation force and friction coefficient are investigated. The material deformation and indentation geometry are extracted based on the final locations of atoms, which are displaced by the rigid tool. In addition to modeling, an AFM was used to conduct actual indentation at the nanoscale, and provide measurements to validate the predictions from the MD simulation. The AFM provides resolution on nanometer (lateral) and angstrom (vertical) scales. A three-sided pyramid indenter (with a radius of curvature ∼ 50 nm) is raster scanned on top of the surface and in contact with it. It can be observed from the MD simulation results that the indentation force increases as the depth of indentation increases, but decreases as the scratching speed increases. On the other hand, the friction coefficient is found to be independent of scratching speed.
A Vertex Translation Algorithm for Adaptive Modification of STL File in Layered Manufacturing
Authors: Navangul Gaurav , Paul Ratnadeep , Anand Sam
Published: September 2011

Rapid Prototyping (RP)/Layered Manufacturing (LM) machines typically use a Stereolithography (STL) file as a basis to manufacture parts. However, the conversion of the part CAD file to STL results in the distortion of the part geometry, particularly if the part consists of freeform curved surfaces. Existing algorithms and software tend to reduce this distortion globally, which increases the size and memory requirements of the STL file. This paper presents a new approach for reducing the CAD to STL translation error locally, using chordal error as the criteria. The algorithm presented here compares the STL file to the design surface of the part, expressed as a NURBS surface, and computes the chordal error for multiple points on the STL facets. The point within each STL facet having the largest chordal error is modified to coincide with its corresponding point on the design surface. This replaces the original facet of the STL file with three new facets with significantly lower chordal error than that of the original facet. This Vertex Translation Algorithm (VTA), reduces the chordal error in areas with high curvature and areas having tighter profile tolerance specifications and provides the user the flexibility to selectively modify the STL file according to the tolerance requirements. The algorithm has been validated with the help of a test case.
Numerical Modeling of Minimum Uncut Chip Thickness for Micromachining With Different Rake Angle
Authors: Shi Z. Y. , Liu Z. Q.
Published: September 2011

In micromachining, when the undeformed chip thickness becomes comparable to the edge radius of the cutting tool, the effective rake angle becomes to be negative and has significant effect on the determination of the minimum uncut chip thickness. The determination of the minimum uncut chip thickness is essential in micro machining in order to achieve desired surface integrity and accuracy. In this paper, an Arbitrary Lagrangian Eulerian (ALE)-based numerical modeling is proposed to determine the minimum uncut chip thickness for Copper by changing the cutting tool’s nominal rake angle. According to the relationship between the minimum uncut chip thickness and the effective rake angle, a mathematical model that reflects the relationship between the effective rake angle and the nominal rake angle is established.
Capillary Force Induced Elastic Deformation on ZnS Nanobeams
Authors: Wang Xinnan , Li Xiaodong
Published: September 2011

In this study, synthesized Wurtzite-structured ZnS nanobelts was investigated using high resolution transmission electron microscope, atomic force microscope, and scanning electron microscope for structural and morphology analyses. Results show that ZnS nanobelts are tens of microns in length, mostly ∼40×50 nm2 in width and thickness. The nanobelts grow along direction [001] and are dislocation free. The distance spacing for (001) plane is 3.19A˚. The capillary force was found strong enough to deform the ZnS nanobeam down to the substrate. Theoretical analysis on small strain elastic deformation was conducted. It was found that as the maximum beam deflection increases, beam elastic energy increases; in the meantime, the surface energy decreases. The net increase in elastic beam energy is less than the net decrease in the surface energy, resulting in total energy decrease. In addition, as the volume of liquid increases, for a certain maximum beam deflection, the total energy increases, this is result of the increase of the surface energy. Furthermore, for a specific nanobeam to be deflected to the underlying surface, the amount of liquid can be calculated.
A Synthetic Biology Approach Reveals a CXCR4-G
13
-Rho Signaling Axis Driving Transendothelial Migration of Metastatic Breast Cancer Cells
Authors: Yagi Hiroshi , Tan Wenfu , Dillenburg-Pilla Patricia , Armando Sylvain , Amornphimoltham Panomwat , Simaan May , Weigert Roberto , Molinolo Alfredo A. , Bouvier Michel , Gutkind J. Silvio
Published: September 2011

Interfering with a specific G protein–coupled receptor pathway may provide a therapeutic approach to blocking metastasis of some forms of breast cancer.
Driven to Exhaustion?
Authors: Foley John F.
Published: September 2011

The transmembrane protein Tim-3, which is associated with T cell exhaustion, enhances T cell receptor signaling pathways.
Modulating Myelination
Authors: Hines Pamela J.
Published: September 2011

Axons signal through both glutamate and adenosine triphosphate release to regulate their insulating wraps.
Gut Reaction
Authors: Ray L. Bryan
Published: September 2011

A receptor for gut hormones also functions in the brain, where its loss affects attention.
Molecular Characterization of UpaB and UpaC, Two New Autotransporter Proteins of Uropathogenic Escherichia coli CFT073
Authors: Allsopp Luke P. , Beloin Christophe , Ulett Glen C. , Valle Jaione , Totsika Makrina , Sherlock Orla , Ghigo Jean-Marc , Schembri Mark A.
Published: September 2011

Uropathogenic
Escherichia coli
(UPEC) is the primary cause of urinary tract infection (UTI) in the developed world. The major factors associated with virulence of UPEC are fimbrial adhesins, which mediate specific attachment to host receptors and trigger innate host responses. Another group of adhesins is represented by the autotransporter (AT) subgroup of proteins. The genome-sequenced prototype UPEC strain CFT073 contains 11 putative AT-encoding genes. In this study, we have performed a detailed molecular characterization of two closely related AT adhesins from CFT073: UpaB (c0426) and UpaC (c0478). PCR screening revealed that the
upaB
and
upaC
AT-encoding genes are common in
E. coli
. The
upaB
and
upaC
genes were cloned and characterized in a recombinant
E. coli
K-12 strain background. This revealed that they encode proteins located at the cell surface but possess different functional properties: UpaB mediates adherence to several ECM proteins, while UpaC expression is associated with increased biofilm formation. In CFT073,
upaB
is expressed while
upaC
is transcriptionally repressed by the global regulator H-NS. In competitive colonization experiments employing the mouse UTI model, CFT073 significantly outcompeted its
upaB
(but not
upaC
) isogenic mutant strain in the bladder. This attenuated phenotype was also observed in single-challenge experiments, where deletion of the
upaB
gene in CFT073 significantly reduced early colonization of the bladder.
Efficient synthesis and biological properties of the 2′-trifluoromethyl analogues of acyclic nucleosides and acyclic nucleoside phosphonates
Authors: Jansa Petr , Kolman Viktor , Kostinová Alexandra , Dračínský Martin , Mertlíková-Kaiserová Helena , Janeba Zlatko
Published: September 2011

Efficient and optimized procedure for the preparation of several acyclic nucleosides and acyclic nucleoside phosphonates substituted at the C-2′ position of the aliphatic part by the trifluoromethyl group is described. Trifluoromethyloxirane was found to be an excellent reagent for the introduction of the 1,1,1-trifluoropropan-2-ol moiety. Surprisingly, the next reaction of these 1,1,1-trifluoropropan-2-ols with the reagent for the introduction of the methylphosphonic residue afforded the desired phosphonates in very high yields and finally a novel simple and scalable procedure for the isolation of free phosphonic acids, after the reaction of dialkyl phosphonates with bromotrimethylsilane, was developed. Prepared compounds were evaluated for their biological properties, but none of the prepared phosphonic acids or acyclic nucleosides exhibits any antiviral, antiproliferative or anti-toxin activities.
Impact of facilitating physician access to relevant medical literature on outcomes of hospitalised internal medicine patients: a randomised controlled trial
Authors: Izcovich Ariel , Malla Carlos Gonzalez , Diaz Martín Miguel , Manzotti Matías , Catalano Hugo Norberto
Published: September 2011

Introduction

There is limited high-quality evidence regarding the usefulness of bibliographic assistance in improving clinically important outcomes in hospitalised patients. This study was designed to evaluate the impact of providing attending physicians with bibliographic information to assist them in answering medical questions that arise during daily clinical practice.

Methods

All patients admitted to the Internal Medicine ward of Hospital Aleman in Buenos Aires between March and August 2010 were randomly assigned to one of two groups: intervention or control. Throughout this period, the medical questions that arose during morning rounds were identified. Bibliographic research was conducted to answer only those questions that emerged during the discussion of patients assigned to the intervention group. The compiled information was sent via e-mail to all members of the medical team.

Results

809 patients were included in the study, 407 were randomly assigned to a search-supported group and 402 to a control group. There was no significant difference in death or transfer to an intensive care unit (ICU) (RR 1.09 (95% CI 0.7 to 1.6)), rehospitalisation (RR 1.0 (95% CI 0.7 to 1.3)) or length of hospitalisation (6.5 vs 6.0 days, p=0.25). The subgroup of search-supported physicians' patients (n=31), whose attending physicians received hand-delivered information, had a significantly lower risk of death or transfer to an ICU compared with the control group (0% vs 13.7%, p=0.03).

Conclusions

The impact of bibliographic assistance on clinically important outcomes could not be proven by this study. However, results suggest that some interventions, such as delivering information by hand, might be beneficial in a subgroup of inpatients.