bluuebunny/crossref_metadata_2025 huggingface dataset:
Hole-Pattern Seals Performance Optimization Using Computational Fluid Dynamics and Design of Experiment Techniques
Authors: Untaroiu Alexandrina , Liu Cheng , Migliorini Patrick J. , Wood Houston G. , Untaroiu Costin D.
Published: April 2014

A main goal of non-contacting mechanical seals is to provide minimal leakage during operation. This may be achieved by specifying a small clearance between the mating faces that is just enough to avoid rubbing contact while allowing some tolerable leakage. The amount of leakage flow is reduced through the acceleration and deceleration of the fluid through a tortuous path, so the sealing performance depends on the geometric characteristics of the leakage path.

This study focuses on annular hole-pattern seals, which are non-contacting mechanical seals commonly used in high pressure compressors. A Design of Experiments (DOE) approach is used to investigate the effects of various geometric variables on the leakage rate of a hole-pattern seal during normal operating conditions. The design space, defined by the ranges of hole diameter, hole depth, axial space between holes and number of holes in circumferential direction, is discretized using the simple random sampling method. Then, steady-state Computational Fluid Dynamics (CFD) simulations are performed at each design point to evaluate seal performance. To better understand the sensitivity of the hole-pattern seal leakage rate with respect to design variables selected, response surfaces are built through its values at design points using quadratic polynomial fitting. The results show that the optimal solution had a better leakage control ability over the base model design. It is believed that the results of this study will assist in improving the design of annular hole-pattern seals.
Design and Performance Testing of a Ducted Savonius Turbine for Marine Current Energy Extraction
Authors: Goundar Jai N. , Prasad Deepak , Ahmed Mohammed Rafiuddin
Published: April 2014

Marine current energy is a reliable and clean source of energy. Several marine current turbines have been developed over the years, most of the turbines perform well at velocities over 2 m/s and need to be installed at depths of 20–40 m. Placing an appropriately designed duct or shroud around the turbine significantly improves the turbine’s performance. Ducted Savonius turbines can operate at low depths, since large clearance is not required because turbulent flow has little effect on the performance of the Savonius rotor. Ducted Savonius turbine has simple components and can be easily fabricated in Pacific Island Countries (PIC) and other places that do not have advanced manufacturing industries. A ducted Savonius turbine was designed for a location in Fiji, to operate at a rated marine current speed of 1.15 m/s and cut in speed of 0.2 m/s. The model of ducted Savonius turbine, scaled down to 1/20, was fabricated and tested in a water stream with a velocity of 0.6 m/s and was validated with commercial Computational Fluid Dynamics (CFD) code ANSYS-CFX. Finally, a full scale numerical model was constructed to study the flow characteristics and compute the performance. The area ratio of the duct of 2.5:1 (inlet to turbine section) shows significant increase in kinetic energy and an improved turbine performance. The maximum efficiency of the turbine is around 50% at a tip speed ratio (TSR) of 3.5 and the maximum power produced is 10 kW at the rated speed of 1.15 m/s and 63.4 kW at a free-stream velocity of 2.15 m/s.
Temperature Measurements of a Gold Nanosphere Solution in Response to Light-Induced Hyperthermia
Authors: Wong Jun Kai , Taylor Robert , Baek Sungchul , Hewakuruppu Yasitha , Jiang Xuchuan , Chen Chuyang
Published: April 2014

Gold nanospheres (GNSs), biocompatible nanoparticles that can be designed to absorb visible and near-infrared light, have shown great potential in induced thermal treatment of cancer cells via Plasmonic Photothermal Therapy (PPTT) [3]. In this study, light induced heating of a water-based dispersion of 20 nm diameter GNSs was investigated at their plasmon resonance wavelength (λ = 520 nm). Temperature changes of the solution at the point of light irradiation were measured experimentally. A heat transfer model was used to verify the experimental data. The effect of two key parameters, light intensity and particle concentration, on the solution’s temperature was investigated. The experimental results showed a significant temperature rise of the GNS solution compared to de-ionized water. The temperature rise of GNS solution was linearly proportional to the concentration of GNS (from 0.25–1.0 C, C = 1×1013 particles per ml) and the light intensity (from 0.25 to 0.5 W cm−2). The experimental data matches the modeling results adequately. Overall, it can be concluded that the hyperthermic ablation of cancer cells via GNS can be achieved by controlled by the light intensity and GNS concentration. A novel component of this study is that a high power lamp source was used instead of a high power laser. This means that only low cost components were used in the current experimental set-up. Moreover, by using suitable filters and white light from the high power lamp source, it is possible to obtain light in many wavelength bands for the study of other nanoparticles with different plasmon wavelength ranges. The current results represtent just one example in this versatile experimental set-up developed. It should be noted, however, the plasmon resonance wavelength used in this study is not within the therapeutic window (750–1300 nm) [13]. Therefore, the GNSs used in this experiment are only applicable to the surface induced thermal treatment of cancer cells, for instance, in the skin.
Towards Thermal Characterization of Pico-Liter Volumes Using the 3Omega Method
Authors: Roy Shilpi , Kodama Takashi , Lingamneni Srilakshmi , Panzer Matthew A. , Asheghi Mehdi , Goodson Kenneth E.
Published: April 2014

The continued efforts in the biological community to optimize methodologies such as PCR and to characterize biological reactions and processes are motivating reductions in sample volume. There is a growing need for the detection of thermal phenomena in these small volumes, such as the heat released by recombination and the effective conductivities and capacities in extremely small fluidic regions. While past work has focused largely on heat transport in essentially bulk fluid volumes, there is a need to scale these techniques to the much smaller volumes of interest for biological and biomedical research.”

This work applies the 3ω measurement technique to μL volumes by using heaters with dimensions of 200–700μm in lengths and 2–5μm in widths. We investigate fluid samples of DI water, silicone oil, and a salt buffer solution to experimentally determine their temperature-dependent thermal properties from 25°C to 80°C. Validation is achieved through comparison of these values of thermal conductivity κ and volumetric heat capacity Cν to literature. The work also demonstrates the device capability to conduct temperature-dependent measurements down to pL droplet volumes by conducting a volume analysis given the dimensions of heaters used, independent of droplet boundary conditions. Sensitivity and uncertainty analyses based on these heater dimensions and surrounding material stack show the detection capabilities of these heaters, as they are optimally designed to maximize signal while accommodating the size restrictions of small volume droplets.
Effects of Process Parameters on Formation of Hybrid Tissue Constructs
Authors: Yan Karen Chang , Hitscherich Pamela , Ferrie James
Published: April 2014

Tissue engineering is a promising aspect of regenerative medicine that is aimed at constructing functional tissues and organs. While progresses in tissue engineering have led successful clinic applications, challenges remain for more complex tissues/organs that require concerted efforts from multiple types of cells. One of the key issues in building replacements for complex tissues/organs is to mimic the organ’s complex natural organization using a mixture of engineered materials and living cells [1]. Electrospinning has shown promise as a technique to create the microenvironment necessary for cell growth and proliferation for tissue engineering applications[2–4], while multiple fabrication methods have been developed to manipulate live cells(e.g. cell printing) [5–7]. To this end, a system integrating polymer electrospinning technique and pressure-driven cell deposition method is currently under development for forming hybrid tissue constructs with living cells and polymers. This study focuses on examining morphology of electrospun fibers as function of processing parameters including working distance and solution flow rate.
Non-Linear Dynamic Magneto Electric Effects in Ferromagnetic-Ferroelectric Layered Composites
Authors: Harutyunyan Satenik , Hasanyan Davresh
Published: April 2014

A non-linear theoretical model including bending and longitudinal vibration effects was developed for predicting the magneto electric (ME) effects in a laminate bar composite structure consisting of magnetostrictive and piezoelectric multi-layers. If the magnitude of the applied field increases, the deflection rapidly increases and the difference between experimental results and linear predictions becomes large. However, the nonlinear predictions based on the present model well agree with the experimental results within a wide range of applied electric field. The results of the analysis are believed to be useful for materials selection and actuator structure design of actuator in actuator fabrication. It is shown that the problem for bars of symmetrical structure is not divided into a plane problem and a bending problem. A way of simplifying the solution of the problem is found by an asymptotic method. After solving the problem for a laminated bar, formula that enable one to change from one-dimensional required quantities to three dimensional quantities are obtained. The derived analytical expression for ME coefficients depend on vibration frequency and other geometrical and physical parameters of laminated composites. Parametric studies are presented to evaluate the influences of material properties and geometries on strain distribution and the ME coefficient. Analytical expressions indicate that the vibration frequency strongly influences the strain distribution in the laminates, and that these effects strongly influence the ME coefficients. It is shown that for certain values of vibration frequency (resonance frequency), the ME coefficient becomes infinity; as a particular case, low frequency ME coefficient were derived as well.
Teaching Computational Fluid Dynamics Using MATLAB
Authors: Ghosh Amitabha , Pantaleón Carlos
Published: April 2014

A set of MATLAB modules has been developed for an introductory graduate course on computational fluid dynamics (CFD) at Rochester Institute of Technology (RIT). These modules can provide a breakthrough in CFD education because they can assist both learning and comprehension, while avoiding analytical mistakes by the CFD learner. With advances in CFD and availability of software, students in upper level fluid mechanics classes have less incentive to learn theory and the tools for abstract thinking. This paper proposes for the first time an alternate approach to teaching and learning of CFD through the use of symbolic computation in MATLAB, while preserving the accuracy and content of abstract analyses.
Quality Evaluation of Solder Bump in PBGA Package for Commercial Product Application Using Laser Ultrasonic Technique
Authors: Gong Jie , Ume I. Charles , Akinade Kola , Chaudhuri Amiya Ray
Published: April 2014

A laser-ultrasound inspection (LUI) system has been successfully applied to detect solder bump defects including missing, misaligned, open, and cracked solder bumps in flip chips, land grid array packages and chip capacitors. This system uses a pulsed laser to induce ultrasound in the chip packages in the thermoelastic regime; it then measures the transient out-of-plane displacement response on the package surface using a laser interferometer. The amplitudes of the out-of-plane displacement are usually in the order of nanometer. The quality of solder bumps is evaluated by analyzing the transient responses. In this paper, this system is used to evaluate quality of solder bumps in plastic ball grid array (PBGA) package on a commercial product. Each chip was divided into 4 quadrants during testing and signal processing. Test results showed that LUI technique is capable of separating good chips from defective chips. Furthermore, LUI technique is able to reveal defect severity at each quadrant for each chip. Finally, chips were cross-sectioned and defects such as open and cracked solder bumps were observed. The cross-section results correlated well with LUI test results. This study demonstrates the feasibility and capability of this system on evaluating the solder bump quality on commercial products.
Modeling Ionic Liquid Based Electrolytes for Lithium Batteries
Authors: Banerjee Soumik
Published: April 2014

Based on ever-growing societal demand for stable energy supply, recent times have witnessed an increasing emphasis on developing energy storage devices such as batteries with improved specific energy and specific power. Among the myriad energy-storage technologies, rechargeable lithium ion batteries are widely used as energy sources for a range of portable electronic devices because of their relatively high specific energy storage capabilities [1]. However, the highest energy storage capacity achieved by a state-of-the-art lithium ion battery is too low to meet current demands in larger applications such as in the automotive industry [1]. The limitation is due, in part, to the limited ionic conductivity of currently used organic electrolytes coupled with their volatility, electrochemical instability and flammability, which raises safety concerns. The development of new generation of lithium ion batteries with significantly improved energy storage would require the selection of novel electrolyte materials with improved performance without compromising on safety standards. In recent years, there has been growing interest in the development of room temperature ionic liquids because they have extremely low vapor pressure, are stable at high temperatures, are highly resistant to oxidation and reduction, possess high ionic conductivity and have tunable electrochemical properties. However, the ionic conductivity of ionic liquids doped with lithium salt is extremely sensitive to the molecular structure of the ions as well as the extent of coordination between neighboring ionic species. In an effort to understand how atomistic interactions determine transport properties of ionic liquids, in the current study, we simulated lithium salt doped pyrrolidinium based ionic liquids using fundamental atomistic simulations. Properties such as density and self-diffusion coefficients were determined from molecular dynamics simulations and compared to experimental data to validate our model. Our simulations indicate that the mobility of lithium ions is limited due to association with multiple salt anions.
Effects of Conductive Nanomaterials on Hydrogen Production During Electrolysis
Authors: Nageshkar V. , Srikanth M. , Jurak E. , Asmatulu R.
Published: April 2014

The world will run out of cheap oil in 20–30 years, causing energy costs to rise, and probably hitting the economies of many nations. Time is now to look for alternative sources of energy, so that a gentle transition from fossil fuels to renewable sources can take place. While several research programs are being conducted mostly on the sun and wind energies, there is one more source that covers 71% of the Earth surface, which is water. Splitting water by electrolysis forms oxygen and hydrogen molecules. Hydrogen has several uses in energy generation, including fuel cells, hydrogen-powered engines and stations, heating, household use, and many others. In this experiment, conductive nanoparticles were dispersed into a tap water at 60 °C with 1M concentration of sulfuric acid solution, and then electric current was passed through the dispersion at different DC voltages, leading to the formation of hydrogen gas at the cathode — the negative side of the cell. The industrial hydrogen production using acid and pressure is very expensive, and at this stage cannot compete with the fossil fuels. However, adding the nanoparticles increased the yield of hydrogen at lower voltages by up to 80%.
Fatigue Damage Diagnosis Using Statistical, Spectral, and Wavelet Analysis Techniques
Authors: Abu-Mahfouz Issam , Banerjee Amit , Abu-Ayyad Ma’moun
Published: April 2014

The objective of this work is to illustrate a comparative investigation into the signatures of crack initiation and propagation using vibration and displacement signals. Experimental tests were performed on low carbon steel specimen under fully reversed bending cycles in a cantilever support configuration. Accelerometer and displacement-sensor vibration signals were collected using a National Instrument data acquisition system. Several methods, such as statistical moments, FFT, Wavelets, and short-time-frequency analysis techniques, were used to analyze the collected signals. It was found that the wavelet analysis gave the most consistent patterns in tracking crack initiation and propagation. For the wavelet analysis, extensive comparative investigation was conducted to select the optimum combination of wavelet packets for crack detection and monitoring.
A Parametric Study of Temperature and Volumetric Flow Rate Parameters of a Data Center Using Multi-Zone Building Energy Simulation
Authors: Phan Long , Lin Cheng-Xian
Published: April 2014

Energy consumption and thermal management have become key challenges in the design of large-scale air-cooled data centers, where perforated tiles are used together with cold and hot aisles to improve thermal management. Although building energy simulation can be used to estimate annual energy consumption of any building, its application in data centers has been very limited in open literature. In this paper, EnergyPlus was utilized to study selected important parameters about perforated tiles, which potentially affect the energy consumption and thermal management of a data center. The data center model has 1120 servers distributed in four rows of rack. The data center with various boundary conditions was investigated under a typical U.S. climate — hot and humid, in Miami, Florida. The key parameters about the temperature and the volumetric flow rate of the supply side have been extensively investigated. A multi-zone approach that resolves the hot and cold aisles was used to simulate the data center. Annual overall energy consumption were compared and analyzed. The simulation results show that energy consumption of the data center is significantly affected by the supply temperature and the system fan supply air flow rate under different conditions. In addition, an optimal supply temperature of 11.8°C, and air flow rate of 2.5 m3/s were found to be the most preferred selection for the data center model investigated.
Mathematical Model on Magnetic Drug Targeting in a Permeable Microvessel
Authors: Shaw S. , Sibanda P. , Murthy P. V. S. N.
Published: April 2014

A mathematical model is presented for predicting magnetic targeting of multifunctional carrier particles that deliver therapeutic agents to malignant tissue in vivo. These particles consist of a nonmagnetic core material that contains embedded magnetic nanoparticles and therapeutic agents such as photodynamic sensitizers. For in vivo therapy, the particles are injected into the micro vascular system upstream from malignant tissue, and captured at the tumor using an applied magnetic field. In this paper, a mathematical model is developed for predicting noninvasive magnetic targeting of therapeutic carrier particles in a micro vessel. The flow of blood in the micro vessel is described by a two phase Herschel-Bulkley fluid model. The Brinkmann model is used to characterize the permeable nature of the inner wall of the micro-vessel. The fluidic force on the carrier traversing the micro-vessel and the magnetic force due to the external magnetic field is taken into account. The model enables rapid parametric analysis of magnetic targeting as a function of key variables including the size of the carrier particle, the properties and volume fraction of the imbedded magnetic nanoparticles, the properties of the magnet, the micro vessel and the permeability of the micro vessel.
Analysis of Friction in Bi-Dimensional Pipe Flow Using Non Conventional Constitutive Models
Authors: Catania Giuseppe , Sorrentino Silvio
Published: April 2014

The design of hydraulic transmission lines for control and actuation requires accurate knowledge of their dynamic response: some standard techniques are known to obtain a consistent dynamic model of a fluid line, including the contribution of inertia, compressibility and friction.

In this paper an efficient procedure is developed for simulating the dynamic response in both the frequency and time domains, focusing the attention on the modal analysis of a discretized model of a fluid line. A bi-dimensional approach is adopted, modeling the laminar flow frequency-dependent friction by means of non-integer order differential laws, which may improve the accuracy of the simulated responses in comparison with more traditional Newtonian models.
Description of Test Setup and Approach to Measure Thermal Properties of Natural and Synthetic Spider Silks at Cryogenic Temperatures
Authors: Munro Troy , Xing Changhu , Marquette Andrew , Ban Heng , Copeland Cameron , Lewis Randolph
Published: April 2014

Spider silk is well-known for its exceptional mechanical properties, such as strength, elasticity and flexibility. Recently, it has been reported that dragline silk from a Nephila clavipes also has an exceptionally high thermal conductivity, comparable to copper when the fiber is stretched. Synthetic spider silks have been spun from spider silk proteins produced in transgenic sources, and their production process has the optimization potential to have properties similar to or better than the natural spider silk. There is interest to measure the thermal properties of natural and synthetic silk at cryogenic temperatures for use of spider silk fibers as heat conduits in systems where component weight is an issue, such as in spacecraft. This low temperature measurement is also of particular interest because of the conformational changes in protein structures, which affect material properties, that occurs at lower temperatures for some proteins. A measurement system has been designed and is being tested to characterize the thermal properties of natural and synthetic spider silks by means of a transient electrothermal method.
Developing a Methodology for Measuring the Comparative Energy Efficiency of Elevators
Authors: Bos Jim , Dell Robert , Wei C. S. , Foley William
Published: April 2014

Existing elevator systems are upgraded approximately every 20 years, providing an opportunity for energy reduction upgrades. This demands complicated analysis because elevators consume energy while at idle and in lifting modes. Traffic patterns, loads and building usage must also be considered in addition to energy recovering potentials. An objective and inclusive measurement methodology for measuring elevator energy efficiency is essential for a valid cost benefit analysis. The necessary requirements for a workable system and a usable first generation solution are presented.
Failure and Sensitivity Analysis of MEMS Based Piezo-Resistive Fingerprint Sensor
Authors: Ganesan Adarsh Venkataraman , Swaminathan Sundaram
Published: April 2014

Micro-electromechanical system (MEMS) is considered as the most promising technology for the development of sensors. MEMS based fingerprint sensors are used in modern day biometrics. They are generally realized using piezo resistive sensing technology in lieu of other technologies because of easy and low cost micro fabrication processes involved. But, such sensors can fail due to a number of stresses developed as it is pressed. In this paper, the first investigation is pertaining to the failure of MEMS based piezoresitive fingerprint sensors. The results indicate the sensors’ ability to withstand the maximum finger pressure. In the second investigation, the sensitivity analysis is performed using open source software, Quite Universal Circuit Simulator (QUCS) and the results are also compared with that obtained from solid mechanical simulation using COMSOL Multiphysics. The final investigation is to evaluate electrical performance of sensors connected in different configurations in circuits.
A Micromechanical Model for Shear-Induced Platelet Damage in Capillaries Within Gray Matter
Authors: Sullivan Daniel J. , Taylor Paul A. , Pelegri Assimina A.
Published: April 2014

In order to expand on potential injury mechanisms to the brain, a micromechanical structural representation of the gray matter must be developed. The gray matter contains a high volume of capillary vasculature that supplies the necessary oxygen required for maintaining healthy cell and brain function. Even short disruptions in this blood supply and the accompanying dissolved oxygen can lead to neuronal cell damage and death. It has been shown that increased shearing forces within the blood, such as those found near stents and artificial heart valves, can lead to platelet activation and aggregation, causing clots to form and potential disruptions in blood flow and oxygen distribution. Current macro-scale computational brain modeling can incorporate the larger main vasculature of the brain, but it becomes too computationally expensive to incorporate the smaller vessels. These larger scale models can be used to reveal how forces to the head are transmitted down to a scale slightly larger than the smallest capillaries within the gray matter. In order to investigate the response and potential damage to capillaries and platelets within the brain, a micromechanical computational model is developed incorporating the gray matter, capillaries, and blood, which is composed of plasma, red blood cells, and platelets. The red blood cells are a necessary component for the model for damage as it comprises almost half of the volume of blood and is the major contributor to the non-Newtonian behavior. The model combines both fluids and viscoelastic solid materials (the gray matter and the vascular wall). The deviatoric stress, strain and strain rate of the platelets in response to an externally applied load is measured and will determine the potential for platelet aggregation and clot formation. The micromechanical model is also used to provide verification and refinement for existing constitutive models for the gray matter used in meso- and macro-scale computational models.
Inhibiting the Re-Deposition of AuSn4 on Au/Ni Metallization Pads by Varying the Accessibility of Cu in Isothermally Aged SAC305 Solder Joints
Authors: Mukherjee Subhasis , Dasgupta Abhijit , Silk Julie , Ong Lay-ling
Published: April 2014

Electroplated Ni/Au over Cu is a popular metallization for printed circuit board (PCB) finish as well as for component leads, especially for wire-bondable high frequency packages, where the gold thickness (≥ 20 μinches) requirement is high for wire bonding. Redeposition of bulk AuSn4 intermetallic compound (IMC) at Au/Ni contact pads of isothermally conditioned SnAgCu (SAC) solder joints is a critical reliability concern in these packages because the interfacial layer between redeposited AuSn4 IMC and initially formed IMC during reflow at the contact pad after reflow is brittle in nature. Redeposition of bulk AuSn4 IMC in Pb-free SAC solder joints (most popularly SAC305) is also believed to be dependent on the degree of access to copper. This study examines the effect of varying gold content (2–5 nominal weight-%) in the solder joint and accessibility to copper (by presence or absence of nickel barrier layer on top of Cu plating) on redeposition of AuSn4 IMCs at the interface of isothermally aged SAC305 solder joints for 720 hours at 121°C (0.8*Tmelt). The modified lap shear Iosipescu specimens used for the study are divided into two batches: i] In the first batch, both the copper platens to be soldered are electroplated with Au and Ni. Ni barrier layers are used to completely stop the solder from accessing the Cu in the substrate ii] In the second batch, one Cu platen is electroplated with Au and Ni barrier layer but the other platen is electroplated only with copper (no Nickel layer), to allow accessibility of Cu from the substrate. Representative solder joints from above two batches are then cross-sectioned and analyzed using environmental scanning electron microscopy (ESEM) and energy-dispersive x-ray spectroscopy (EDX) to investigate the composition, thickness and morphology of both bulk and interfacial IMCs. The first phase to form at the interface of the first batch of specimens after initial reflow is Ni3Sn4/(Ni,Cu)3Sn4. During the subsequent solid-state annealing, the redeposition of AuSn4 occurred in systems plated with Au/Ni on both sides. Contrarily, in the second batch when the solder joint has copper access from one side of the joint, the first intermetallic after reflow to form is (Cu,Ni,Au)6Sn5/(Cu,Au)6Sn5 and no redeposition of AuSn4 is observed after solid state annealing except for the solder joint containing nominal 5wt-% of Au.
Exploration of Impinging Water Spray Heat Transfer at System Pressures Near the Triple Point
Authors: Golliher Eric L. , Yao Shi-chune
Published: April 2014

The heat transfer of a water spray impinging upon a surface in a very low pressure environment is of interest to cooling of space vehicles during launch and re-entry, and to industrial processes where flash evaporation occurs. At very low pressure, the process occurs near the triple point of water, and there exists a transient multiphase transport problem of ice, water and water vapor. At the impingement location, there are three heat transfer mechanisms: evaporation, freezing and sublimation. A preliminary heat transfer model was developed to explore the interaction of these mechanisms at the surface and within the spray.
Introduction to the Special Issue on Taika Waititi's Boy
Authors: Smith Jo , Mercier O. Ripeka
Published: April 2014

Introduction to the Special Issue on Taika Waititi's Boy
Shaking the Frame: Taika Waititi's Anti-Anthropological Edge
Authors: Smith Jo
Published: April 2014

Shaking the Frame: Taika Waititi's Anti-Anthropological Edge
Dramatic Lives, Cross-Cultural Memories: Notes on Taika Waititi's Boy
Authors: Moyo Arifani
Published: April 2014

Dramatic Lives, Cross-Cultural Memories: Notes on Taika Waititi's Boy
Pituitary Expression of CTLA-4 Mediates Hypophysitis Secondary to Administration of CTLA-4 Blocking Antibody
Authors: Iwama Shintaro , De Remigis Alessandra , Callahan Margaret K. , Slovin Susan F. , Wolchok Jedd D. , Caturegli Patrizio
Published: April 2014

CTLA-4 blocking antibody induces secondary hypophysitis by binding to CTLA-4 antigen and initiating a type II hypersensitivity reaction.
Cell Distance Mapping Identifies Functional T Follicular Helper Cells in Inflamed Human Renal Tissue
Authors: Liarski Vladimir M. , Kaverina Natalya , Chang Anthony , Brandt Daniel , Yanez Denisse , Talasnik Lauren , Carlesso Gianluca , Herbst Ronald , Utset Tammy O. , Labno Christine , Peng Yahui , Jiang Yulei , Giger Maryellen L. , Clark Marcus R.
Published: April 2014

Visualizing and quantifying the spatial relationships between T and B cells identifies adaptive immune cell networks in human inflammation.
Exon-Skipping Therapy: A Roadblock, Detour, or Bump in the Road?
Authors: Hoffman Eric P. , McNally Elizabeth M.
Published: April 2014

Exon skipping is a promising therapeutic for Duchenne muscular dystrophy patients, but the road to drug approvals is foggy and may require more early-stage de-risking and regulatory guidance.
Dancing with the Scars: Choreography of the Macrophage Two Step After Myocardial Infarction
Authors: Price Elvin
Published: April 2014

A nuclear receptor coordinates monocytes and macrophage subsets and functions after myocardial infarction to maximize healing.
Anti-Infective Activities of Lactobacillus Strains in the Human Intestinal Microbiota: from Probiotics to Gastrointestinal Anti-Infectious Biotherapeutic Agents
Authors: Liévin-Le Moal Vanessa , Servin Alain L.
Published: April 2014

A vast and diverse array of microbial species displaying great phylogenic, genomic, and metabolic diversity have colonized the gastrointestinal tract. Resident microbes play a beneficial role by regulating the intestinal immune system, stimulating the maturation of host tissues, and playing a variety of roles in nutrition and in host resistance to gastric and enteric bacterial pathogens. The mechanisms by which the resident microbial species combat gastrointestinal pathogens are complex and include competitive metabolic interactions and the production of antimicrobial molecules. The human intestinal microbiota is a source from whichLactobacillusprobiotic strains have often been isolated. Only six probioticLactobacillusstrains isolated from human intestinal microbiota, i.e.,L. rhamnosusGG,L. caseiShirota YIT9029,L. caseiDN-114 001,L. johnsoniiNCC 533,L. acidophilusLB, andL. reuteriDSM 17938, have been well characterized with regard to their potential antimicrobial effects against the major gastric and enteric bacterial pathogens and rotavirus. In this review, we describe the current knowledge concerning the experimental antibacterial activities, including antibiotic-like and cell-regulating activities, and therapeutic effects demonstrated in well-conducted, placebo-controlled, randomized clinical trials of these probioticLactobacillusstrains. What is known about the antimicrobial activities supported by the molecules secreted by such probioticLactobacillusstrains suggests that they constitute a promising new source for the development of innovative anti-infectious agents that act luminally and intracellularly in the gastrointestinal tract.
Genital Chlamydia trachomatis: Understanding the Roles of Innate and Adaptive Immunity in Vaccine Research
Authors: Vasilevsky Sam , Greub Gilbert , Nardelli-Haefliger Denise , Baud David
Published: April 2014

Chlamydia trachomatisis the leading cause of bacterial sexually transmitted disease worldwide, and despite significant advances in chlamydial research, a prophylactic vaccine has yet to be developed. This Gram-negative obligate intracellular bacterium, which often causes asymptomatic infection, may cause pelvic inflammatory disease (PID), ectopic pregnancies, scarring of the fallopian tubes, miscarriage, and infertility when left untreated. In the genital tract,Chlamydia trachomatisinfects primarily epithelial cells and requires Th1 immunity for optimal clearance. This review first focuses on the immune cells important in a chlamydial infection. Second, we summarize the research and challenges associated with developing a chlamydial vaccine that elicits a protective Th1-mediated immune response without inducing adverse immunopathologies.
RIG-I Detects mRNA of Intracellular Salmonella enterica Serovar Typhimurium during Bacterial Infection
Authors: Schmolke Mirco , Patel Jenish R. , de Castro Elisa , Sánchez-Aparicio Maria T. , Uccellini Melissa B. , Miller Jennifer C. , Manicassamy Balaji , Satoh Takashi , Kawai Taro , Akira Shizuo , Merad Miriam , García-Sastre Adolfo
Published: April 2014

The cytoplasmic helicase RIG-I is an established sensor for viral 5′-triphosphorylated RNA species. Recently, RIG-I was also implicated in the detection of intracellular bacteria. However, little is known about the host cell specificity of this process and the bacterial pathogen-associated molecular pattern (PAMP) that activates RIG-I. Here we show that RNA of
Salmonella enterica
serovar Typhimurium activates production of beta interferon in a RIG-I-dependent fashion only in nonphagocytic cells. In phagocytic cells, RIG-I is obsolete for detection of
Salmonella
infection. We further demonstrate that
Salmonella
mRNA reaches the cytoplasm during infection and is thus accessible for RIG-I. The results from next-generation sequencing analysis of RIG-I-associated RNA suggest that coding bacterial mRNAs represent the activating PAMP.

IMPORTANCE
S. Typhimurium
is a major food-borne pathogen. After fecal-oral transmission, it can infect epithelial cells in the gut as well as immune cells (mainly macrophages, dendritic cells, and M cells). The innate host immune system relies on a growing number of sensors that detect pathogen-associated molecular patterns (PAMPs) to launch a first broad-spectrum response to invading pathogens. Successful detection of a given pathogen depends on colocalization of host sensors and PAMPs as well as potential countermeasures of the pathogen during infection. RIG-I-like helicases were mainly associated with detection of RNA viruses. Our work shows that S. Typhimurium is detected by RIG-I during infection specifically in nonimmune cells.
Discovering Functions of Unannotated Genes from a Transcriptome Survey of Wild Fungal Isolates
Authors: Ellison Christopher E. , Kowbel David , Glass N. Louise , Taylor John W. , Brem Rachel B.
Published: April 2014

Most fungal genomes are poorly annotated, and many fungal traits of industrial and biomedical relevance are not well suited to classical genetic screens. Assigning genes to phenotypes on a genomic scale thus remains an urgent need in the field. We developed an approach to infer gene function from expression profiles of wild fungal isolates, and we applied our strategy to the filamentous fungusNeurospora crassa. Using transcriptome measurements in 70 strains from two well-defined clades of this microbe, we first identified 2,247 cases in which the expression of an unannotated gene rose and fell acrossN. crassastrains in parallel with the expression of well-characterized genes. We then used image analysis of hyphal morphologies, quantitative growth assays, and expression profiling to test the functions of four genes predicted from our population analyses. The results revealed two factors that influenced regulation of metabolism of nonpreferred carbon and nitrogen sources, a gene that governed hyphal architecture, and a gene that mediated amino acid starvation resistance. These findings validate the power of our population-transcriptomic approach for inference of novel gene function, and we suggest that this strategy will be of broad utility for genome-scale annotation in many fungal systems.

IMPORTANCESome fungal species cause deadly infections in humans or crop plants, and other fungi are workhorses of industrial chemistry, including the production of biofuels. Advances in medical and industrial mycology require an understanding of the genes that control fungal traits. We developed a method to infer functions of uncharacterized genes by observing correlated expression of their mRNAs with those of known genes across wild fungal isolates. We applied this strategy to a filamentous fungus and predicted functions for thousands of unknown genes. In four cases, we experimentally validated the predictions from our method, discovering novel genes involved in the metabolism of nutrient sources relevant for biofuel production, as well as colony morphology and starvation resistance. Our strategy is straightforward, inexpensive, and applicable for predicting gene function in many fungal species.
Acute cardiac tamponade in light-chain amyloidosis
Authors: Kuprian Mikhail , Mount George
Published: April 2014

A 71-year-old woman, with a history of light-chain amyloidosis, presented with a sudden onset dyspnoea. Echocardiography showed a large pericardial effusion with compression of the right atrium and the right ventricle. Right heart catheterisation demonstrated equalisation of her diastolic pressures consistent with cardiac tamponade. Pericardiocentesis revealed a haemmorrhagic exudative effusion with no evidence of malignancy. Bone marrow biopsy and other investigations showed no evidence of multiple myeloma. Her effusion recurred 2 weeks later and repeat pericardiocentesis demonstrated similar findings. She was started on chemotherapy with no further recurrence of pericardial effusion. The patient was unable to tolerate chemotherapy and died 1 year after initial presentation. This case represents a rare manifestation of cardiac amyloidosis and explores the reported aetiologies for cardiac tamponade in the setting of light-chain amyloidosis. Acute and definitive treatments are also discussed.
Non-familial cherubism: clinical and radiological findings
Authors: Agrawal Anuradha , Gupta Saurabh Kumar , Saxena Payal , Kumar Pratiksha
Published: April 2014

Cherubism is a rare, self-limiting, usually hereditary, benign fibro-osseous disease mostly affecting the jaws of the paediatric population. The disease is characterised by bilateral, diffuse and multilocular bony enlargement of the mandible and maxilla, and a tendency towards spontaneous remission. It has a typical radiographic and histopathological appearance. We present a case of a 9-year-old child lacking family history of this genetic disorder.
Recurrent bilateral periorbital and circumoral bruising due to vomiting
Authors: AI-Sardar Hussain
Published: April 2014

Periorbital ecchymosis is due to extravasations of blood into the periorbital skin and the subcutaneous tissues around the eyes. ‘raccoon eyes’ or ‘panda sign’ is a distinctive type of periorbital ecchymosis where the bruising is characterised by tarsal sparing. This sparing is due to an anatomical structure called the orbital septum, which limits the spread of the discolouration beyond the tarsal plate. Hence ‘raccoon eyes’ description should be limited to orbital ecchymosis due to basal skull fractures only. While the bilateral bruising due to direct trauma to the eyes, or non-traumatic medical conditions, can spread beyond the tarsal plate as in our case. The differential diagnosis varies from trivial benign conditions to serious life-threatening illnesses. We describe a case of recurrent bilateral periorbital ecchymosis and facial bruising due to vomiting.
Placental site nodule (PSN): an uncommon diagnosis with a common presentation
Authors: Pramanick Angsumita , Hwang Wei Sek , Mathur Manisha
Published: April 2014

Placental site nodule (PSN) is a rare benign lesion of the intermediate trophoblast which is thought to represent incomplete involution of the placental implantation site. PSN usually presents as menorrhagia, intermenstrual bleeding or an abnormal Pap smear. PSN is benign, but it is important to distinguish it from the other benign and malignant lesions like decidua, placental polyp, exaggerated placental site and placental site trophoblastic tumour. Follow-ups of typical PSNs do not show recurrence or malignant potential. PSN is an uncommon condition which should be suspected in cases of abnormal bleeding, especially following uterine surgical procedures preceding last pregnancy. Timely diagnosis and treatment is necessary to differentiate it from potentially malignant placental lesions with a similar presentation.
Dynamic tube movement after reimplantation of Ahmed glaucoma valve in a child with glaucoma in aphakia
Authors: Senthil Sirisha , Badakare Akshay
Published: April 2014

A 10-year-old girl underwent an Ahmed glaucoma valve (AGV) implantation as a primary procedure for glaucoma in aphakia due to congenital cataract surgery. Following an unintended accidental excision of AGV tube during bleb revision for hypertensive phase, AGV was explanted and a second AGV was implanted in the same quadrant after 2 weeks. This resulted in a rare complication of dynamic tube movement in the anterior chamber with tube corneal touch and localised corneal oedema. Excision of the offending unstable tube and placement of a paediatric AGV in a different quadrant led to resolution of this complication, stable vision and well-controlled intraocular pressure. This case highlights the possible causes of dynamic tube, related complications and its management. This case also highlights the importance of understanding the various physiological phases after glaucoma drainage device implantation and their appropriate management.
Septic arthritis secondary to rat bite fever: a challenging diagnostic course
Authors: Budair Basil , Goswami Karan , Dhukaram Vivek
Published: April 2014

We describe a challenging diagnostic course of a case of septic arthritis secondary to rat bite fever (Streptobacillus moniliformis) in a 29-year-old man who presented with generalised malaise, polyarthralgia and bilateral palmoplantar rash.
External iliac artery dissection causing early renal transplant dysfunction
Authors: Lee Gwyn , Barlow Adam , Doughman Tahir , Nicholson Michael L
Published: April 2014

External iliac artery dissection after kidney transplantation is a rare, catastrophic but potentially reversible complication. Treatment which may save both the transplant and the patient requires clinical suspicion, timely imaging, and prompt intervention. This case report describes successful diagnosis of this complication and surgical intervention which saved the kidney and safeguarded blood supply to the patient's leg.
Effect of aneurysm and ICA morphology on hemodynamics before and after flow diverter treatment
Authors: Larrabide Ignacio , Geers Arjan J , Morales Hernán G , Aguilar Martha L , Rüfenacht Daniel A
Published: April 2014

Background

Flow diverter (FD) treatment aims to slow down blood flow inside the aneurysm and increase the average time that blood resides in the aneurysm.

Objective

To investigate the relationship between vessel and aneurysm morphology and their influence on the way in which braided FDs change intra-aneurysmal hemodynamics.

Materials and methods

Twenty-three patient-specific intracranial aneurysm models at the supraclinoid segment of the internal carotid artery were studied. Vessel and aneurysm morphology was quantified and blood flow was modeled with computational fluid dynamics simulations. The relation between morphologic variables and the hemodynamic variables,WSS(wall shear stress) andtotime(ratio between the aneurysm volume and inflow at the aneurysm neck), was assessed statistically.

Results

Intra-aneurysmal flow was less dependent on the vessel than on aneurysm morphology. In summary, after treatment with a FD, a greater aneurysm flow reduction and redirection to the vessel main stream should be expected for (a) aneurysms located further away from the curvature peak, (b) aneurysms on the inner side of the bend, (c) aneurysms with no proximal stenosis, and (d) larger aneurysms.

Conclusions

Although the change in intra-aneurysmal hemodynamics after FD treatment strongly depends on the morphology of the aneurysm, the hemodynamic effect of a FD is also linked to the parent vessel morphology and the position and orientation of the aneurysm with respect to it.
Seismic design of basement walls: evaluation of current practice in British Columbia
Authors: Taiebat Mahdi , Amirzehni Elnaz , Finn W.D.L.
Published: April 2014

The current state of practice for the seismic design of basement walls in Vancouver is based on the Mononobe–Okabe (M–O) method using a peak ground acceleration (PGA) of 0.46g mandated by the National Building Code of Canada (NBCC). A series of dynamic numerical analyses are conducted to study the seismic performance of basement walls designed for the M–O earth pressures derived from different fractions of the current building code mandated PGA. The walls are subjected to seven ground motions spectrally matched to the uniform hazard spectrum (UHS) prescribed by the NBCC for Vancouver. The analyses show that current engineering practice for designing basement walls based on the M–O method and using a PGA of 0.46g is too conservative. The analyses suggest that a wall designed using a 50%–60% PGA will give an acceptable performance in terms of drift ratio. The results of sensitivity analyses on input parameters are also presented and discussed.