bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Damage Detection Using Slopes of Longitudinal Vibration Shapes
Authors: Xu W. , Zhu W. D. , Smith S. A.
Published: March 2016

While structural damage detection based on flexural vibration shapes, such as mode shapes and steady-state response shapes under harmonic excitation, has been well developed, little attention is paid to that based on longitudinal vibration shapes that also contain damage information. This study originally formulates a slope vibration shape for damage detection in bars using longitudinal vibration shapes. To enhance noise robustness of the method, a slope vibration shape is transformed to a multiscale slope vibration shape in a multiscale domain using wavelet transform, which has explicit physical implication, high damage sensitivity, and noise robustness. These advantages are demonstrated in numerical cases of damaged bars, and results show that multiscale slope vibration shapes can be used for identifying and locating damage in a noisy environment. A three-dimensional (3D) scanning laser vibrometer is used to measure the longitudinal steady-state response shape of an aluminum bar with damage due to reduced cross-sectional dimensions under harmonic excitation, and results show that the method can successfully identify and locate the damage. Slopes of longitudinal vibration shapes are shown to be suitable for damage detection in bars and have potential for applications in noisy environments.
Grinding Wheel Surface Topography for Multiple Pass With Incremental Depth of Cut of Rotary Diamond Dresser
Authors: Chowdhury M. A. K.
Published: March 2016

Grinding is often used material removal process in manufacturing. A grinding wheel has abrasive grains on its working surface and the material removal efficiency of a grinding wheel decreases with grinding operations. To restore the material removal efficiency of a grinding wheel, dressing is performed. There are several types of dressing methods and among these different methods, mechanical dressing is widely performed. In mechanical dressing, rotary diamond dresser is one of the effective dressers. The grinding wheel surface topography induced from dressing effect the performance of subsequent grinding operation. Therefore, grinding wheel preparation conditions, i.e., dressing conditions and consequently the grinding wheel surface topography have effect on grinding performance. The actual cutting points on diamond grits of a rotary diamond dresser are micro cutting tools which interact with the working surface of the grinding wheel. This interaction of the diamond grits of rotary diamond dresser restores the material removal efficiency of the grinding wheel. In precision engineering, multiple pass and incremental depth of cut of dresser is applied to increase the overall efficiency. This study deals with the surface topography of grinding wheel due to multiple pass and incremental depth of cut dressing operations by rotary diamond dresser. The objective of a dressing operation is to sharpen and protrude the abrasive grits embedded on the working surface of a grinding wheel. To achieve this, the rotary dresser should come in contact with all parts of the working surface of a grinding wheel without hitting the same location repeatedly. A simulation tool has been developed correlating the rotary diamond dresser parameters, grinding wheel parameters and dressing process parameters. In this research, a method is developed which enables one to determine the trajectories of dresser on the working surface of a grinding wheel (i.e., surface topography of grinding wheel) after performing dressing operations multiple times wherein the depth of cut is increased after each pass. A modified simulation is used to visualize surface topography of a grinding wheel for multiple pass with incremental depth of cut. The simulation tool also determines the dressing ratio (percent of working area of grinding wheel that has been dressed) and the areas which are dressed twice or more. Using the modified simulation tool, some strategies, i.e., single pass and multi pass dressing with incremental depth of cut is identified for determining optimal dressing conditions (the dressing conditions for which the dresser covers all circumferential surface of a grinding wheel without dressing the same area repeatedly).
Theoretical Analysis of Transient Bioheat Transfer in Multi-Layer Tissue
Authors: Sarkar Daipayan , Haji-Sheikh A. , Jain Ankur
Published: March 2016

Heat conduction in skin tissue is a problem of significant technological importance. A theoretical understanding of such a problem is essential as it may lead to design potential therapeutic measures for needed cancer therapy or novel medical devices for various applications including hyperthermia. To understand the physical phenomenon of energy transport in biological systems a transient model is chosen for this study. The most common transport equation to estimate temperature distribution in humans was developed by H.H. Pennes and is popularly known as the Pennes bioheat transfer equation. A generalized Pennes bioheat transfer equation accounts for the effect of various physical phenomena such as conduction, advection, volumetric heat generation, etc. are considered. In this paper, a general transient form of the Pennes bioheat transfer equation is solved analytically for a multilayer domain. The boundary value problem considers the core of the tissue is maintained at uniform temperature of 37°C, convective cooling is applied to the external surface of the skin and the sidewalls are adiabatic. The computation of transient temperature in multidimensional and multilayer bodies offers unique features. Due to the presence of blood perfusion in the tissue, the reaction term in the Pennes governing equation is modeled similar to a fin term. The eigenvalues may become imaginary, producing eigenfunctions with imaginary arguments. In addition the spacing between the eigenvalues between zero and maximum value varies for different cases; therefore the values need to be determined with precision using second order Newton’s method. A detailed derivation of the temperature solution using the technique of separation of variables is presented in this study. In addition a proof of orthogonality theorem for eigenfunctions with imaginary eigenvalues is also presented. The analytical model is used to study the thermal response of skin tissue to different parameters with the aid of some numerical examples. Results shown in this paper are expected to facilitate a better understand of bioheat transfer in layered tissue such as skin.
Modeling of Fracture Behaviours of Ultrasonically Welded Cu-Cu Joints Under Different Loading Conditions
Authors: Xi Liang , Banu Mihaela , Hu S. Jack , Cai Wayne , Rinker Teresa
Published: March 2016

A lithium-ion battery pack for electric vehicles may consist of several hundreds of battery cells joined together. Each cell contains joints of multiple thin sheets of electrodes of different conductive materials such as nickel coated copper, copper and / or aluminum. These within-cell and cell-to-cell joints must withstand static and dynamic mechanical loading. Determination of their maximum loading capacity is a very important task in order to predict the life of a battery pack. The standard procedure is to apply mechanical tests, such as lap shear and pull test to each joint. This procedure is time consuming and costly. There is a strong interest nowadays in developing validated models which can predict the actual behavior of the joints under different loadings and the associated failure modes. In this paper, two finite element models are developed to predict the strength of ultrasonically welded two-, three- and four layer joints of 0.2 mm thickness copper tabs with a 1mm thickness busbar. These models have the ability to predict three modes of failure of these joints depending on the weld quality, e.g., interfacial fracture, combined interfacial-circumferential fracture, and circumferential failure. These models are experimentally validated with very good agreement between experimental and predicted results.
Investigation of Effect of Non-Uniformities in Unidirectional Carbon Fiber Composite on the Lcr Waves Speed Using Phased Arrays
Authors: Vieira Gonçalves Vanessa , Antunes dos Santos Auteliano , Pereira Paulo
Published: March 2016

Structural parts benefit on a reliable, nondestructive inspection technique to measure stresses, both applied and residual. Among the candidates, ultrasonic techniques have proven to have enough sensitivity to strain to be employed in service. The way to obtain the stresses is through the measurement of the time-of-flight inside the material and relates it to the strain by acoustoelastic theory or previous measurements. However, stress measurement using ultrasound strongly depends on the uniformity of the material under inspection. In composite materials, the time-of-flight is influenced by microdefects and misalignments in the fibers as well as by the applied strain and temperature. This last factor can be known and controlled, but non uniformities are a characteristic of one particular region or part. Thus, unless employed to a very particular case of a completely uniform region been inspected in a special developed part, UT could not be used to measure stresses in this kind of material without some previous information about it. This work presents an investigation about the effect of non-uniformities in carbon fiber-epoxy pre-preg composites and how to relate them with the time-of-flight of critically refracted longitudinal waves (Lcr) propagating in the fiber direction (main structural direction). A Phased Array System (PAS) with probe of 5 MHz and 64 transducers are employed to generate an image of each part in the region where the Lcr wave travels. The image is created employing the Total Focusing Method (TFM). Two bars of carbon fiber composites with epoxy matrix (HexTow® AS4 / Hexply® 8552) were tested. Five measurement positions are selected, uniformly distributed on the part surface. Statistically significant differences between the parts were found in the time-of-flight for Lcr waves when no stress is applied; even knowing they were manufactured using the same process and materials. The parts were evaluated using the PAS. No difference was found between measurements in the same bar. The parameter chosen to evaluate the non-uniformity was the peak value of the back-wall signal divided by the RMS value of the noise intensity, which was called signal-to-noise ratio (SNR). The results show also significant difference between the SNR of both parts, although with higher dispersion than with Lcr. It can be noticed that there is a correlation between the time-of-flight of Lcr waves and the SNR, indicating that the research could be extended to the development of a new joint technique to be used to measure stresses in composite parts.
Evaluations of Engineering Uncertainty Repository
Authors: Takai Shun , Du Xiaoping
Published: March 2016

In the ideal world, everything can be modeled and manufactured precisely. Unfortunately, in the real world, it is impossible to make artifacts with exact dimensions and exact material properties. Current engineering education focuses on teaching engineering science with precise analytical relationships among input and output variables and various properties of materials. Variations of product performances due to manufacturing variations and unpredictable use environments, however, have not been sufficiently incorporated into engineering education. An Engineering Uncertainty Repository is currently being developed with an intention to enhance students’ uncertainty literacy and to assist instructors to incorporate uncertainty into their engineering courses. This paper presents (1) the ongoing development of the Engineering Uncertainty Repository, which includes a dedicated website and teaching materials, and (2) a plan to evaluate the effectiveness of the Engineering Uncertainty Repository.
Characterization of Micromist for Effective Machining
Authors: Li Qibo , Lerma Iram , Alvarado Jorge , Edinbarough Immanuel , Hung Wayne N. P.
Published: March 2016

This study presents wetting characteristic of several lubricants for minimum quantity lubrication (MQL) by comparing their respective contact angles on different tool and workpiece materials. The size of an airborne droplet is estimated by measuring the profile of average droplets depositing on a polished and flat glass surface. The droplet velocity field in front of a nozzle is simulated numerically, and compared against measured data using anemometry and laser particle image velocimetry techniques.

A favorable contact angle of ∼5° is obtained for oil-based lubricants on titanium, stainless steel, and tungsten carbide samples. Such low contact angle is preferred over a higher contact angle of ∼30° typically found when using water-based cutting fluids. The micromist used in the study forms a conical flow of ∼ 20° in front of a coaxial nozzle. High air pressure can atomize lubricant into microdroplets with characteristics droplets of 4–11 μm in size, which are comparable with published data for microdroplet diameters. An optimum size of 3–5 μm microdroplets is preferred since airborne microdroplets below 2 μm may cause a health concern to some machine operators. When the input pressure is above 300 kPa, the air speed in front of a nozzle is at least 100 m/s (6,000 m/min) along a working distance of 20–100 mm from the nozzle tip. Since this droplet speed could be 5 times faster than the cutting speed of a diamond tool in ultrahigh speed machining, such microdroplet could penetrate the boundary layer of a fast rotating tool, adhere and wet the tool and workpiece surfaces for effective lubrication and heat removal. The axial microdroplet speed, however, is drastically reduced in the direction perpendicular to the flow due to vortices forming beyond ∼50 mm downstream from the nozzle tip. A single nozzle would be sufficient for a single point cutting tool — as in turning operation — if the working distance is short and the airstream is near the laminar regime, but multiple MQL nozzles should be utilized for a larger milling tool.
Effect of Fiber Architecture on the Fracture Strength of Implant/Bio-Material Interfaces
Authors: Li Yanling , Riahinezhad Shahram , Khandaker M.
Published: March 2016

Titanium (Ti) and Ti-based alloys are widely used as implants for hard tissue repair. However, the optimal surface properties for ideal integration of Ti implant with native tissues have not yet been achieved. The goal of this study was to improve the bio-mechanical performances of titanium (Ti) implant by implant surface modification such as coating fiber on the implant surface. It is hypothesized that deposition of fiber with certain architecture can increase mechanical interlock of Ti surface which leads to the increment of in vitro bonding of Ti/cement interfaces. The research objectives were to (1) test the fracture strength of Ti-cement with one round, two rounds and five rounds of PCL fiber under static load to determine the topology effect of electrospun fiber material on the Ti/PMMA cement interface; (2) test the fracture strength of Ti-cement with PCL fiber and PCL-PMMA fiber, with and without heating up Ti before fiber under static load to determine the topography effect of electrospun fiber material on the Ti/PMMA cement interface. PCL and PCL-PMMA fibers coated on the Ti surfaces were produced by electrospinning technique using PCL-acetone fiber solution and PCL-PMMA-acetone solution respectively. Under static conditions, Ti/PMMA union specimen with and without fiber were tested to determine the fracture strength. The result showed one round of PCL fiber has higher fracture strength than two rounds and five rounds of fiber, which suggested that more fibers on the surface were not benefit to the fracture strength of Ti-cement interface. With PMMA added into the polymer fiber solution, the fracture strength of Ti-fiber-cement increased. Heating up the Ti implant to 50°C before coating PCL fiber can help the PCL fiber become stickier to the Ti implant which leads to the increasing of the fracture strength of Ti-cement interface. However, for PCL-PMMA fiber, heating up Ti implant before fiber doesn’t help improve the quality of Ti-cement interface as PCL fiber.
Dynamic Modeling and Analysis of Three-Dimensional Slack Cables With Application to Elevator Traveling Cables
Authors: Zhu W. D. , Mao Y. G. , Ren G. X.
Published: March 2016

This paper addresses three-dimensional dynamic modeling of a moving elevator traveling cable with bending and torsional stiffnesses and arbitrarily moving ends. An absolute nodal coordinate formulation based on Rayleigh beam theory is introduced to model the traveling cable. Dynamic equations of motion, which are presented as differential algebraic equations, are solved by the backward differentiation formula. Equilibria of a traveling cable with different cable parameters and car positions are first calculated. Motions of cable ends are prescribed next to simulate the free response of the traveling cable due to motion of the car. Finally, effects of different types of building sways on dynamic responses of the traveling cable are examined.
Effects of Helical Rod Profiles in Helical Abrasive Flow Machining (HLX-AFM) Process
Authors: Brar B. S. , Walia R. S. , Singh V. P. , Singh P.
Published: March 2016

Abrasive flow machining (AFM) process is a fine finishing process employing abrasive laden self modulating putty for the finishing of mainly internal recesses. Though the AFM is suitable for the finishing of internal cavities, but the material removal is very low during this finishing process. Helical abrasive flow machining (HLX-AFM) has been recently developed to improve the machining efficiency of AFM process. This process employs a coaxially fixed helical twist drill-bit during the extrusion of the abrasive laden media through an internal cylindrical recess. The presence of a fixed drill-bit inside a cylindrical cavity of the work-piece results in considerable increase in material removal and improvement in surface finish. In the present investigation, the same HLX-AFM setup has been used and the effects of two more helical profile rods viz. a 3-start helical profile and a spline have been studied along with the helical twist drill-bit for improving the quality characteristics of material removal and percentage improvement in the surface roughness during the fine finishing of internal cylindrical surface of brass work-pieces. The experiments were planned according to L9 orthogonal array of Taguchi method and the optimal process parameters were selected. The employment of a rod with six splines and a 3-start helical profile results in improved finishing in comparison to the drill-bit profile, due to the presence of more number of flutes and grooves on the coaxially held stationary rods. The helical profile type has 3.75% contribution towards the percentage improvement in the surface roughness, but is not significant in affecting material removal. The presence of 3-start helical profile led to 61.40% improvement in surface roughness (from Ra - 1.3 μm to 0.5 μm) at optimal level with no effect on material removal, which means no extra machining is taking place. The parameter of abrasive-to-media concentration ratio (varying from 0.75 to 1.25) is the most contributing factor with 85.90% contribution toward suface finish improvement and 71.71% contribution towards material removal. The finishing performance of 3-start profile is 15% better than the standard helical drill-bit with no increase in the operating pressures. SEM micrographs corroborated the fact that 3-start profile led to more number of light abrasive cutting grooves and thus more surface finish. HLX-AFM with 3-start helical profile rods can be employed for the finishing, form corrections of internal cylindrical cavities of any size. Presence of the profile rod results in increase in the reduction ratio and thus more machining action. The developed process can also generate cross-hatch lay pattern on internal cylindrical surfaces.
Performance Analysis of Gas-Expanded Lubricants in a Hybrid Bearing Using Computational Fluid Dynamics
Authors: Weaver Brian K. , Fu Gen , Clarens Andres F. , Untaroiu Alexandrina
Published: March 2016

Gas-expanded lubricants (GELs), tunable mixtures of synthetic oil and dissolved carbon dioxide, have been previously shown to potentially increase bearing efficiency, rotordynamic control, and long-term reliability in flooded journal bearings by controlling the properties of the lubricant in real time. Previous experimental work has established the properties of these mixtures and multiple numerical studies have predicted that GELs stand to increase the performance of flooded bearings by reducing bearing power losses and operating temperatures while also providing control over bearing stiffness and damping properties. However, to date all previous analytical studies have utilized Reynolds equation-based approaches while assuming a single-phase mixture under high-ambient pressure conditions. The potential implications of multi-phase behavior could be significant to bearing performance, therefore a more detailed study of alternative operating conditions that may include multi-phase behavior is necessary to better understanding the full potential of GELs and their effects on bearing performance. In this work, the performance of GELs in a fixed geometry journal bearing were evaluated to examine the effects of these lubricants on the fluid and bearing dynamics of the system under varying operating conditions. The bearing considered for this study was a hybrid hydrodynamic-hydrostatic bearing to allow for the study of various lubricant supply and operating conditions. A computational fluid dynamics (CFD)-based approach allowed for a detailed evaluation of the lubricant injection pathway, the flow of fluid throughout the bearing geometry, thermal behavior, and the collection of the lubricant as it exits the bearing. This also allowed for the study of the effects of the lubricant behavior on overall bearing performance.
Conducting Engineering Research Experiments in a Senior Mechanical Engineering Instructional Laboratory
Authors: Hadady Hanie , Wetta Daniel J. , Geiger Emil J.
Published: March 2016

Engineering teaching laboratory experiments often suffer from being too deterministic. While this can allow students to predictably observe and measure various engineering phenomena, the students may doubt the real world application or significance of the experiment. On the other hand, engineering research experiments can often be tedious and repetitive. Research assistants, both graduate and undergraduate, can grow bored while collecting data, leading to mistakes and reduced quality of the data. This paper will present preliminary results from using a laboratory section of a senior mechanical engineering elective course, “Introduction to Microtechnology,”, to conduct a series of experiments for a research problem in the instructor’s research laboratory.
Ion energy control in reactive ion etching using 1-MHz pulsed-DC square-wave-superimposed 100-MHz RF capacitively coupled plasma
Authors: Ui Akio , Hayashi Hisataka , Sakai Itsuko , Kaminatsui Takeshi , Ohiwa Tokuhisa , Yamamoto Katsumi , Kikutani Keisuke
Published: March 2016

For the precise control of the ion energy in reactive ion etching (RIE), a 1-MHz pulsed-direct current (DC) square-wave-superimposed (p-DCS) 100-MHz radio frequency (RF) capacitively coupled plasma (CCP) is studied and compared with a 13.56- and 100-MHz dual-RF-superimposed (DFS) CCP. The proposed CCP is applied in RIE for sub-32-nm node etching of spun-on-carbon using H2-based gas at 2.66 Pa and 1200 W of 100-MHz RF power. A minimum critical dimension shift of 3 nm is achieved at high etch rates in p-DCS CCP using an optimized square-wave voltage of −750 V, compared with a corresponding shift of 9 nm in DFS CCP using 400 W of 13.56-MHz RF power. Because the maximum of the ion energy distribution (IED) is controlled by the square-wave voltage and more than 70% of the total ion flux is concentrated in a narrow range around the maximum ion energy, the CCP offers precise control of the IED, which is effective in the RIE of the fine-patterned devices.
Development of a Computational Elbow Model with Experimental Validation of Kinematics and Muscle Forces
Authors: Kusins Jonathan R. , Willing Ryan , King Graham J.W. , Ferreira Louis M.
Published: March 2016

A computational elbow joint model was developed with a main goal of providing complimentary data to experimental results. The computational model was developed and validated using an experimental elbow joint phantom consisting of a linked total joint replacement. An established in-vitro motion simulator was used to actively flex/extend the experimental elbow in multiple orientations. Muscle forces predicted by the computational model were similar to the experimental model in 4 out of the 5 orientations with errors less than 7.5 N. Valgus angle kinematics were in agreement with differences less than 2.3°. In addition, changes in radial head length, a clinically relevant condition following elbow reconstruction, were simulated in both models and compared. Both lengthening and shortening of the radial head prosthesis altered muscle forces by less than 3.5 N in both models, and valgus angles agreed within 1°. The computational model proved valuable in cross validation with the experimental model, elucidating important limitations in the in-vitro motion simulator’s controller. With continued development, the computational model can be a complimentary tool to experimental studies by providing additional noninvasive outcome measurements.
Cell type–specific glycosylation of Orai1 modulates store-operated Ca
2+
entry
Authors: Dörr Kathrin , Kilch Tatiana , Kappel Sven , Alansary Dalia , Schwär Gertrud , Niemeyer Barbara A. , Peinelt Christine
Published: March 2016

T cells and mast cells may use differential glycosylation of Orai1 to regulate store-operated calcium signaling.
Sterol hindrance of Orai activation
Authors: Hooper Robert , Rothberg Brad S. , Soboloff Jonathan
Published: March 2016

Cholesterol inhibits CRAC channels, which replenish intracellular stores.
Papers of note in
Science
Authors: VanHook Annalisa M. , Gough Nancy R.
Published: March 2016

This week’s articles feature insights into how PKA may stop cancer and how the immune system uses endogenous retroviruses.
Enhancement of the Replication of Hepatitis C Virus Replicons of Genotypes 1 to 4 by Manipulation of CpG and UpA Dinucleotide Frequencies and Use of Cell Lines Expressing SECL14L2 for Antiviral Resistance Testing
Authors: Witteveldt Jeroen , Martin-Gans Marion , Simmonds Peter
Published: March 2016

Treatment for hepatitis C virus (HCV) has improved greatly through the use of direct-acting antivirals (DAAs). However, their effectiveness and potential for drug resistance development in non-genotype 1 variants of HCV remain relatively unexplored, as
in vitro
assays to assess drug susceptibility are poorly developed and unsuited for a transient-transfection format. In the current study, we have evaluated the effects of dinucleotide frequency changes in the replicon and the use of a SEC14L2-expressing cell line on the replication of HCVs of different genotypes and evaluated the resulting assay formats for measurements of susceptibility to the DAA sofosbuvir. Removal of CpG and UpA dinucleotides from the luciferase gene used in HCV replicons of genotype 1b (Con1) and genotype 2a (JFH-1) achieved between 10- and 100-fold enhancement of replication over that of the wild type posttransfection. Removal of CpG and UpA dinucleotides in the neomycin gene or deletion of the whole gene in replicons of genotype 3a (S52) and genotype 4a (ED43) enhanced replication, but phenotypic effects on altering luciferase gene composition were minimal. A further 10-fold replication enhancement of replicons from all four genotypes was achieved by using a transgenic Huh7.5 cell line expressing SECL14L2, whose expression showed a dose-dependent effect on HCV replication that was reversible by small interfering RNA (siRNA) knockdown of gene expression. By combining these strategies, the 100- to 1,000-fold enhancement of replication allowed the susceptibility of all four genotypes to the RNA polymerase inhibitor sofosbuvir to be robustly determined in a transient-transfection assay format. These methods of replication enhancement provide new tools for monitoring the susceptibility and resistance of a wide range of HCV genotypes to DAAs.
Inhibitors of Ribosome Rescue Arrest Growth of Francisella tularensis at All Stages of Intracellular Replication
Authors: Goralski Tyler D. P. , Dewan Kalyan K. , Alumasa John N. , Avanzato Victoria , Place David E. , Markley Rachel L. , Katkere Bhuvana , Rabadi Seham M. , Bakshi Chandra Shekhar , Keiler Kenneth C. , Kirimanjeswara Girish S.
Published: March 2016

Bacteria require at least one pathway to rescue ribosomes stalled at the ends of mRNAs. The primary pathway for ribosome rescue is
trans
-translation, which is conserved in >99% of sequenced bacterial genomes. Some species also have backup systems, such as ArfA or ArfB, which can rescue ribosomes in the absence of sufficient
trans
-translation activity. Small-molecule inhibitors of ribosome rescue have broad-spectrum antimicrobial activity against bacteria grown in liquid culture. These compounds were tested against the tier 1 select agent
Francisella tularensis
to determine if they can limit bacterial proliferation during infection of eukaryotic cells. The inhibitors KKL-10 and KKL-40 exhibited exceptional antimicrobial activity against both attenuated and fully virulent strains of
F. tularensis
in vitro
and during
ex vivo
infection. Addition of KKL-10 or KKL-40 to macrophages or liver cells at any time after infection by
F. tularensis
prevented further bacterial proliferation. When macrophages were stimulated with the proinflammatory cytokine gamma interferon before being infected by
F. tularensis
, addition of KKL-10 or KKL-40 reduced intracellular bacteria by >99%, indicating that the combination of cytokine-induced stress and a nonfunctional ribosome rescue pathway is fatal to
F. tularensis
. Neither KKL-10 nor KKL-40 was cytotoxic to eukaryotic cells in culture. These results demonstrate that ribosome rescue is required for
F. tularensis
growth at all stages of its infection cycle and suggest that KKL-10 and KKL-40 are good lead compounds for antibiotic development.
Functional Equivalence of OspA and OspB, but Not OspC, in Tick Colonization by Borrelia burgdorferi
Authors: Tilly Kit , Bestor Aaron , Rosa Patricia A.
Published: March 2016

Borrelia burgdorferi
, a Lyme disease agent, makes different major outer surface lipoproteins at different stages of its mouse–tick infectious cycle. Outer surface protein A (OspA) coats the spirochetes from the time they enter ticks until they are transmitted to a mammal. OspA is required for normal tick colonization and has been shown to bind a tick midgut protein, indicating that OspA may serve as a tick midgut adhesin. Tick colonization by spirochetes lacking OspA is increased when the infecting blood meal is derived from mice that do not produce antibody, indicating that OspA may protect the spirochetes from host antibody, which will not recognize tick-specific proteins such as OspA. To further study the importance of OspA during tick colonization, we constructed a form of
B. burgdorferi
in which the
ospA
open reading frame, on lp54, was replaced with the
ospC
gene or the
ospB
gene, encoding a mammal-specific or tick-specific lipoprotein, respectively. These fusions yielded a strain that produces OspC within a tick (from the fusion gene) and during early mammalian infection (from the normal
ospC
locus) and a strain that produces OspB in place of OspA within ticks. Here we show that the related, tick-specific protein OspB can fully substitute for OspA, whereas the unrelated, mammal-specific protein OspC cannot. These data were derived from three different methods of infecting ticks, and they confirm and extend previous studies indicating that OspA both protects spirochetes within ticks from mammalian antibody and serves an additional role during tick colonization.
Serial Dissection of Parasite Gene Families
Authors: Bzik David J.
Published: March 2016

Calcium ion signaling regulates central aspects of the biology controlling stage and life cycle transitions of apicomplexan parasites. In the current issue of
Infection and Immunity
, Long and coworkers (S. Long, Q. Wang, and L. D. Sibley, Infect Immun 84:1262–1273, 2016,
http://dx.doi.org/10.1128/IAI.01173-15
) describe a powerful genetic system enabling reliable serial genetic dissection of a large gene family encoding novel calcium-dependent protein kinases (CDPKs) that provides new insights into the roles of CDPKs during
Toxoplasma gondii
infection.
Cohort profile: the Spanish WORKing life Social Security (WORKss) cohort study
Authors: López Gómez María Andrée , Durán Xavier , Zaballa Elena , Sanchez-Niubo Albert , Delclos George L , Benavides Fernando G
Published: March 2016

Purpose

The global economy is changing the labour market and social protection systems in Europe. The effect of both changes on health needs to be monitored in view of an ageing population and the resulting increase in prevalence of chronic health conditions. The Spanish WORKing life Social Security (WORKss) cohort study provides unique longitudinal data to study the impact of labour trajectories and employment conditions on health, in terms of sickness absence, permanent disability and death.

Participants

The WORKss cohort originated from the Continuous Working Life Sample (CWLS) generated by the General Directorate for the Organization of the Social Security in Spain. The CWLS contains a 4% representative sample of all individuals in contact with the Social Security system. The WORKss cohort exclusively includes individuals with a labour trajectory from 1981 or later. In 2004, the cohort was initiated with 1 022 779 Social Security members: 840 770 (82.2%) contributors and 182 009 (17.8%) beneficiaries aged 16 and older.

Findings to date

The WORKss cohort includes demographic characteristics, chronological data about employment history, retirement, permanent disability and death. These data make possible the measurement of incidence of permanent disability, the number of potential years of working life lost, and the number of contracts and inactive periods with the Social Security system. The WORKss cohort was linked to temporary sickness absence registries to study medical diagnoses that lead to permanent disability and consequently to an earlier exit from the labour market in unhealthy conditions.

Future plans

Thanks to its administrative source, the WORKss cohort study will continue follow-up in the coming years, keeping the representativeness of the Spanish population affiliated to the Social Security system. The linkage between the WORKss cohort and temporary sickness absence registries is envisioned to continue. Future plans include the linkage of the cohort with mortality registries.
Cross-sectional study examining whether the extent of first-contact access to primary care differentially benefits those with certain personalities to receive preventive services
Authors: Pandhi Nancy , Schumacher Jessica R , Thorpe Carolyn T , Smith Maureen A
Published: March 2016

Objective

The extent of first-contact access to primary care (ie, easy availability when needed) is associated with receiving recommended preventive services. Whether this access benefits patients at risk of preventive services underutilisation, such as those with certain personality characteristics, is unclear.

Setting

Secondary analysis of the 2003–2006 round of the Wisconsin Longitudinal Study.

Participants

6975 respondents who reported a usual provider whose specialty was internal medicine or family medicine. Those reporting not visiting a medical provider in the past 12 months, and those who were uninsured were excluded.

Primary outcome measures

Receiving mammography, cholesterol testing and influenza vaccination. Adjusted predicted probabilities (aPP) of receiving these services were analysed stratified by personality characteristics overall, and if significant, then interacted with first-contact access.

Results

Lower conscientiousness as compared with higher conscientiousness predicted less of all 3 preventive services; mammography (aPP 80%; 95% CI (77% to 83%) vs aPP 85%; (95% CI 82% to 87%)), cholesterol testing (88%; (85% to 90%) vs 93% (91% to 94%), and influenza vaccination (62%; (59% to 64%) vs 66%; (63% to 68%)). Lower agreeableness as compared with higher agreeableness predicted less mammography (77%; (73% to 81%) vs 84%; (82% to 87%)) and less influenza vaccination (59%; (56% to 62%) vs 65%; (63% to 68%)). Lower extraversion predicted less cholesterol testing (88%; (86% to 91%) vs (92%; (90% to 94%)). Lower openness to experience predicted less influenza vaccination (59%; (56% to 63%) vs (68%; (65% to 70%)). For agreeableness, these differences in receiving preventive services did not persist when first-contact access to primary care was present.

Conclusions

Certain personality characteristics predicted receiving less preventive care services. For those with less agreeableness, improved first-contact access to primary care mitigated this effect. If these results are replicated in other studies, primary care offices seeking to improve population health through receiving preventive services should prioritise increasing their first-contact accessibility.
Normal platelet function in platelet concentrates requires non-platelet cells: a comparative in vitro evaluation of leucocyte-rich (type 1a) and leucocyte-poor (type 3b) platelet concentrates
Authors: Parrish William R , Roides Breana , Hwang Julia , Mafilios Michael , Story Brooks , Bhattacharyya Samir
Published: March 2016

Background

Therapeutic success of platelet-rich plasma (PRP) may vary based on the composition and preparation method. The objective of this study was to evaluate the cellular components of platelet concentrates produced by a leucocyte-rich (LR-PRP) and a leucocyte-poor PRP systems (LP-PRP).

Methods

Parameters evaluated included platelet recovery, platelet concentration, red blood cell (RBC) and white blood cell (WBC) composition, platelet growth factor release and stimulation of human tendon cell proliferation in vitro.

Results

Platelet recoveries were 52% for LP-PRP and 89% for LR-PRP. LR-PRP demonstrated greater reproducibility with a 4.2% coefficient of variation (CV) compared with 19.4% for LP-PRP (p<0.001). LR-PRP demonstrated a greater increase in platelet concentration (7.9-fold) than LP-PRP (2.2-fold; p<0.001). LP-PRP showed 5.0-fold reductions in WBCs, while LR-PRP showed a 4.0-fold increase (p<0.001). LP-PRP reduced RBCs to a haematocrit of 0.25, while LR-PRP reduced haematocrit to 11.8. LP-PRP did not coagulate robustly on reactivation with CaCl2, and released significantly lower levels of epidermal growth factor (EGF) and transforming growth factor β1 (TGF-β1) than whole blood (p<0.03). LP-PRP also did not stimulate tendon cell proliferation greater than whole blood. In contrast, LR-PRP showed increases in each growth factor on activation with CaCl2(p<0.01) and stimulated greater proliferation (p<0.05) compared with whole blood. Forced activation of LP-PRP with exogenous thrombin rescued the coagulation deficiency and induced greater growth factor release than comparable whole blood (p<0.03).

Conclusions

These data suggest that non-platelet cellular components in platelet concentrates are important for proper platelet function, including thrombin generation, growth factor release and clot retraction.
Upconversion luminescence properties and color tunability of 12CaO⋅7Al2O3:Ho3+/Yb3+ single crystal
Authors: Qu Yunfei , Qiu Zhaozhong , Wang Rui , Liu Liang , Tao Ye , Zhou Jianjun
Published: March 2016

Rear earth (RE) ions-doped 12CaO[Formula: see text]7Al2O3 single crystal has been successfully prepared by Czochralski method. Under 980 nm excitation, a strong green upconversion emission at 548 nm and a weaker red upconversion emission at 662 nm were observed. The green upconversion emission is corresponding to the transition of 5F 4/5S[Formula: see text]I8 of Ho[Formula: see text], and the red one is corresponding to the transition of 5F[Formula: see text]I8 of Ho[Formula: see text]. A much weaker NIR band at 762 nm is also observed, which corresponds to the 5F 4/5S[Formula: see text]I7 transition of Ho[Formula: see text]. The pump dependence and luminescence decay dynamics spectra show the green and red upconversion are populated by two-photon process, and the upconversion mechanisms are analyzed in detail. The color of the upconversion luminescence can be changed by simply adjusting the excitation power. RE ions-doped 12CaO[Formula: see text]7Al2O3 single crystal with these properties is expected to have broad application prospects in solid-state multicolor display and instrument integration. RE ions-doped 12CaO[Formula: see text]7Al2O3 single crystal has the ability to replace some traditional single crystals such as LiNbO3 in many applications.
How Do Homeowners Choose Between Fixed and Adjustable Rate Mortgages?
Authors: Mugerman Yevgeny , Ofir Moran , Wiener Zvi
Published: March 2016

Housing is the most important asset in the portfolio of most households. Understanding the households’ decision on housing finance has important implications from a policy perspective, due to the effects it may have on the housing prices, on the housing market stability and on household welfare. The theoretical literature on housing finance focused on figuring out the optimal choice between fixed rate mortgages (FRMs) and adjustable rate mortgages (ARMs). We argue that the standard economic criteria are sometimes inadequate to explain household’s choices, which may be motivated by psychological factors. In other words, we claim that household’s choice depends only partially on the findings of the theoretical literature. We examine the effect of changes in the short-term market interest rate on the households’ choice between FRMs and ARMs. We test this effect using a unique data provided to us by the Bank of Israel, which contains detailed information on the household’s decision between FRM and ARM contracts in Israel in the past decade. The results of our analysis demonstrate a significant association between FRM preference and short-term interest rate reduction. Moreover, we find that the change in the short-term interest rate is more salient to the borrowers in periods of a high interest rate environment. We attribute these findings to Tversky and Kahneman (1974) availability and representativeness heuristics.
Skeletal inflammation and attenuation of Wnt signaling, Wnt ligand expression, and bone formation in atherosclerotic ApoE-null mice
Authors: Liu Yu , Almeida Maria , Weinstein Robert S. , O'Brien Charles A. , Manolagas Stavros C. , Jilka Robert L.
Published: March 2016

ApoE-null (ApoE-KO) mice fed a high-fat diet (HFD) develop atherosclerosis, due in part to activation of vascular inflammation by oxidized low-density lipoprotein. Since bone loss also occurs in these mice, we used them to investigate the impact of oxidized lipids on bone homeostasis and to search for underlying pathogenic pathways. Four-month-old female ApoE-KO mice fed a HFD for three months exhibited increased levels of oxidized lipids in bone, as well as decreased femoral and vertebral trabecular and cortical bone mass, compared with ApoE-KO mice on normal diet. Despite HFD-induced increase in expression of Alox15, a lipoxygenase that oxidizes LDL and promotes atherogenesis, global deletion of this gene failed to ameliorate the skeletal impact of HFD. Osteoblast number and function were dramatically reduced in trabecular and cortical bone of HFD-fed mice, whereas osteoclast number was modestly reduced only in trabecular bone, indicating that an imbalance in favor of osteoclasts was responsible for HFD-induced bone loss. These changes were associated with decreased osteoblast progenitors and increased monocyte/macrophages in the bone marrow as well as increased expression of IL-1β, IL-6, and TNF. HFD also attenuated Wnt signaling as evidenced by reduced expression of Wnt target genes, and it decreased expression of pro-osteoblastogenic Wnt ligands. These results suggest that oxidized lipids decrease bone mass by increasing anti-osteoblastogenic inflammatory cytokines and decreasing pro-osteoblastogenic Wnt ligands.
Factors Associated with Delay in Presentation to the Hospital for Young Adults with Ischemic Stroke
Authors: Leung Lester Y. , Caplan Louis R.
Published: March 2016

Objectives: Young adults with ischemic stroke may present late to medical care, but the reasons for these delays are unknown. We sought to identify factors that predict delay in presentation. Methods: We performed a retrospective cohort study of adults aged 18-50 admitted to a single academic medical center between 2007 and 2012. Results: Eighty six of 141 (61%) young adults with ischemic stroke presented at the health center more than 4.5 h after stroke onset. Diabetes was associated with delays in presentation (p = 0.033, relative risk (RR) 1.4 (95% CI 1.1-1.8)), whereas systemic cancer was associated with early presentations (p = 0.033, RR 0.26 (95% CI 0.044-1.6)). Individuals who were single were more likely to present late than those who were married or living with a partner (p = 0.0045, RR 1.7 (95% CI 1.3-2.2)). Individuals who were unemployed were more likely to present late than those who were employed or in school (p = 0.020, RR 1.4 (95% CI 1.1-1.8)). Age (dichotomized as 18-35 and 36-50), race, home medications, other medical conditions (including common stroke mimics in young adults), and stroke subtype were not determinants of delay in presentation, although there was a trend toward delayed presentations in women (p = 0.076) and with low stroke severity (dichotomized as National Institutes of Health Stroke Scale (NIHSS) ≤5 and NIHSS >5, p = 0.061). Conclusions: A majority of young adults with ischemic stroke presented outside the time window for intravenous fibrinolysis. Diabetes, single status, and unemployed status were associated with delayed presentation.
Alteration of Motor Protein Expression Involved in Bidirectional Transport in Peripheral Blood Mononuclear Cells of Patients with Amyotrophic Lateral Sclerosis
Authors: Kuźma-Kozakiewicz Magdalena , Kaźmierczak Beata , Chudy Agnieszka , Gajewska Beata , Barańczyk-Kuźma Anna
Published: March 2016

Background: Sporadic amyotrophic lateral sclerosis (SALS) is a fatal motor neuron degenerative disease of unclear pathogenesis. Disturbances of intracellular transport are possible causes of the disease. Objective: We evaluated the expression of motor proteins involved in the anterograde (kinesins KIF1B, KIF5C) and retrograde (KIFC3, dynactin subunits DCTN1 and DCTN3) intracellular transport in peripheral blood mononuclear cells (PBMCs). Materials and Methods: PBMCs were obtained from 74 SALS patients with different clinical phenotypes, 65 blood donors (healthy control I), and 29 cases with other neurological diseases (disease control II) divided into subgroups IIA (atypical parkinsonism) and IIB (ALS-mimicking disorders). mRNA expression was studied by real-time qPCR, and protein level by Western blotting. Results: In SALS, KIF5C and KIFC3 expression was significantly lower and DCTN1 higher than in control I, and dependent of age. KIF1B expression was significantly higher in SALS than in subgroup IIB, whereas DCTN1 and DCTN3 were higher in SALS than in subgroup IIA. All changes in the studied proteins were statistically significant in classic ALS but not in progressive muscular atrophy. Conclusion: In SALS, and especially in classic ALS, the changes in motor protein expression may alter bidirectional intracellular transport in PBMCs. More studies are needed to find out whether the levels of KIF5C and DCTN1 may be useful in ALS diagnosis, and whether KIF1B expression may discriminate ALS from ALS-mimicking disorders.