bluuebunny/crossref_metadata_2025 huggingface dataset:
Stochastic Reassembly Strategy for Managing Information Complexity in Heterogeneous Materials Analysis and Design
Authors: Xu Hongyi , Greene M. Steven , Deng Hua , Dikin Dmitriy , Brinson Catherine , Kam Liu Wing , Burkhart Craig , Papakonstantopoulos George , Poldneff Mike , Chen Wei
Published: September 2013

Design of high performance materials system requires highly efficient methods for assessing microstructure–property relations of heterogeneous materials. Toward this end, a domain decomposition, affordable analysis, and subsequent stochastic reassembly approach is proposed in this paper. The approach hierarchically decomposes the statistically representative cell (representative volume element (RVE)) into computationally tractable unrepresentative ones (statistical volume element (SVE)) at the cost of introducing uncertainty into subdomain property predictions. Random property predictions at the subscale are modeled with a random field that is subsequently reassembled into a coarse representation of the RVE. The infinite dimension of microstructure is reduced by clustering SVEs into bins defined by common microstructure attributes, with each bin containing a different apparent property random field. We additionally mitigate the computational burden in this strategy by presenting an algorithm that minimizes the number of SVEs required for convergent random field characterization. In the proposed method, the RVE thus becomes a coarse representation, or mosaic, of itself. The mosaic approach maintains sufficient microstructure detail to accurately predict the macroproperty but becomes far cheaper from a computational standpoint. A nice feature of the approach is that the stochastic reassembly process naturally creates an apparent-SVE property database whose elements may be used as mosaic building blocks. This feature enables material design because SVE-apparent properties become the building blocks of new, albeit conceptual, material mosaics. Some simple examples of possible designs are shown. The approach is demonstrated on polymer nanocomposites.
Exact Constraint Design of a Two-Degree of Freedom Flexure-Based Mechanism1
Authors: Brouwer Dannis M. , Folkersma (Ger) K. G. P. , Boer Steven E. , Aarts Ronald G. K. M.
Published: September 2013

We present the exact constraint design of a two degrees of freedom cross-flexure-based stage that combines a large workspace to footprint ratio with high vibration mode frequencies. To maximize unwanted vibration mode frequencies the mechanism is an assembly of optimized parts. To ensure a deterministic behavior the assembled mechanism is made exactly constrained. We analyze the kinematics of the mechanism using three methods; Grüblers criterion, opening the kinematic loops, and with a multibody singular value decomposition method. Nine release-flexures are implemented to obtain an exact constraint design. Measurements of the actuation force and natural frequency show no bifurcation, and load stiffening is minimized, even though there are various errors causing nonlinearity. Misalignment of the exact constraint designs does not lead to large stress, it does however decrease the support stiffness significantly. We conclude that designing an assembled mechanism in an exactly constrained manner leads to predictable stiffnesses and modal frequencies.
PCB Origami: A Material-Based Design Approach to Computer-Aided Foldable Electronic Devices
Authors: Sterman Yoav , Demaine Erik D. , Oxman Neri
Published: September 2013

Origami is traditionally implemented in paper, which is a passive material. This research explores the use of material with embedded electronics such as printed circuit boards (PCB) as the medium for origami folding to create an interactive folding experience and to generate foldable objects with added functionalities. PCBs are produced as 2D shapes. By folding PCB arrays, it is possible to create 3D objects that contain electronic functions. Conductivity, output devices (such as light emitting diodes) and microcontroller computation can create an interactive folding experience, for user guidance and verification of the folding. We call this approach and methodology PCB origami. The work presented in this paper describes two unique interaction and fabrication techniques for creating and folding electronic materials. We demonstrate prototypes and present verification/evaluation strategies for guiding the user through the folding process.
Automatic Generation of a Pattern of Geometric Features for Industrial Design
Authors: Andrade Diego F. , Shimada Kenji
Published: September 2013

This paper presents a new computational method for the automatic generation of geometric feature patterns for industrial design. Such patterns include speaker holes, showerhead holes, and bumpy textures on a grip, and they play a key role in making a designed object aesthetically pleasing and functional. While modern CAD packages support the automated creation of basic patterns, rectangular grids, and radial grids, they are not applicable to more general cases required in industrial design, including arbitrarily shaped target geometry and graded feature sizes. The proposed computational method takes as input a target region along with sizing metrics and generates feature patterns automatically in three steps: (1) packing circles tightly in the target region, (2) scaling features according to the specified sizing metrics, and (3) adding features on the base geometry. The proposed method is installed as a plugin module to a commercial CAD package, and a pattern of hundreds of features can be added to a 3D CAD model in less than 5 min. This allows the industrial designer to explore more design alternatives by avoiding the tedious and time-consuming manual generation of patterns.
Accommodating Thickness in Origami-Based Deployable Arrays1
Authors: Zirbel Shannon A. , Lang Robert J. , Thomson Mark W. , Sigel Deborah A. , Walkemeyer Phillip E. , Trease Brian P. , Magleby Spencer P. , Howell Larry L.
Published: September 2013

The purpose of this work is to develop approaches to accommodate thickness in origami-based deployable arrays with a high ratio of deployed-to-stowed diameter. The origami flasher model serves as a basis for demonstrating the approach. A thickness-accommodating mathematical model is developed to describe the flasher. Practical modifications are presented for the creation of physical models and two options are proposed: allowing the panels to fold along their diagonals or applying a membrane backing with specified widths at fold-lines. The mathematical model and hardware modifications are employed to create several physical models. The results are general and apply to a range of applications. An example is provided by the application that motivated the work: a deployable solar array for space applications. The model is demonstrated in hardware as a 1/20th scale prototype with a ratio of deployed-to-stowed diameter of 9.2 (or 1.25 m deployed outer diameter to 0.136 m stowed outer diameter).
Sensitivity of the Numerical Prediction of Turbulent Combustion Dynamics in the LIMOUSINE Combustor
Authors: Shahi Mina , Kok Jim B. W. , Pozarlik Artur K. , Roman Casado J. C. , Sponfeldner Thomas
Published: September 2013

The objective of this study is to investigate the sensitivity and accuracy of the reaction flow-field prediction for the LIMOUSINE combustor with regard to choices in computational mesh and turbulent combustion model. The LIMOUSINE combustor is a partially premixed, bluff body-stabilized natural gas combustor designed to operate at 40–80 kW and atmospheric pressure and used to study combustion instabilities. The transient simulation of a turbulent combusting flow with the purpose to study thermoacoustic instabilities is a very time-consuming process. For that reason, the meshing approach leading to accurate numerical prediction, known sensitivity, and minimized amount of mesh elements is important. Since the numerical dissipation (and dispersion) is highly dependent on, and affected by, the geometrical mesh quality, it is of high importance to control the mesh distribution and element size across the computational domain. Typically, the structural mesh topology allows using much fewer grid elements compared to the unstructured grid; however, an unstructured mesh is favorable for flows in complex geometries. To explore computational stability and accuracy, the numerical dissipation of the cold flow with mixing of fuel and air is studied first in the absence of the combustion process. Thereafter, the studies are extended to combustible flows using standard available ansys-cfx combustion models. To validate the predicted variable fields of the combustor's transient reactive flows, the numerical results for dynamic pressure and temperature variations, resolved under structured and unstructured mesh conditions, are compared with experimental data. The obtained results show minor dependence on the used mesh in the velocity and pressure profiles of the investigated grids under nonreacting conditions. More significant differences are observed in the mixing behavior of air and fuel flows. Here, the numerical dissipation of the (unstructured) tetrahedral mesh topology is higher than in the case of the (structured) hexahedral mesh. For that reason, the combusting flow, resolved with the use of the hexahedral mesh, presents better agreement with experimental data and demands less computational effort. Finally, in the paper, the performance of the combustion model for reacting flow is presented and the main issues of the applied combustion modeling are reviewed.
Miura-Base Rigid Origami: Parameterizations of First-Level Derivative and Piecewise Geometries
Authors: Gattas Joseph M. , Wu Weina , You Zhong
Published: September 2013

Miura and Miura-derivative rigid origami patterns are increasingly used for engineering and architectural applications. However, geometric modelling approaches used in existing studies are generally haphazard, with pattern identifications and parameterizations varying widely. Consequently, relationships between Miura-derivative patterns are poorly understood, and widespread application of rigid patterns to the design of folded plate structures is hindered. This paper explores the relationship between the Miura pattern, selected because it is a commonly used rigid origami pattern, and first-level derivative patterns, generated by altering a single characteristic of the Miura pattern. Five alterable characteristics are identified in this paper: crease orientation, crease alignment, developability, flat-foldability, and rectilinearity. A consistent parameterization is presented for five derivative patterns created by modifying each characteristic, with physical prototypes constructed for geometry validation. It is also shown how the consistent parameterization allows first-level derivative geometries to be combined into complex piecewise geometries. All parameterizations presented in this paper have been compiled into a matlab Toolbox freely available for research purposes.
Design and Optimization of a Shape Memory Alloy-Based Self-Folding Sheet
Authors: Peraza-Hernandez Edwin , Hartl Darren , Galvan Edgar , Malak Richard
Published: September 2013

Origami engineering—the practice of creating useful three-dimensional structures through folding and fold-like operations on two-dimensional building-blocks—has the potential to impact several areas of design and manufacturing. In this article, we study a new concept for a self-folding system. It consists of an active, self-morphing laminate that includes two meshes of thermally-actuated shape memory alloy (SMA) wire separated by a compliant passive layer. The goal of this article is to analyze the folding behavior and examine key engineering tradeoffs associated with the proposed system. We consider the impact of several design variables including mesh wire thickness, mesh wire spacing, thickness of the insulating elastomer layer, and heating power. Response parameters of interest include effective folding angle, maximum von Mises stress in the SMA, maximum temperature in the SMA, maximum temperature in the elastomer, and radius of curvature at the fold line. We identify an optimized physical realization for maximizing folding capability under mechanical and thermal failure constraints. Furthermore, we conclude that the proposed self-folding system is capable of achieving folds of significant magnitude (as measured by the effective folding angle) as required to create useful 3D structures.
Numerical Analysis of Active Vibro-Acoustic Control in an Enclosed Cavity
Authors: Elwali Wael , Li Mingfeng , Lim Teik C.
Published: September 2013

A numerical model is applied to study the application of active vibro-acoustic control in an enclosed cavity. The vibro-acoustic problem is composed of a free-free beam, representing the windshield, coupled with a rectangular planar acoustic cavity, representing the passenger compartment. Forces at the windshield boundaries are actively applied to reduce noise due to floor panel vibrations and sound from a monopole source. Noise transfer functions are used to calculate the control forces based on their ability to minimize the acoustic energy distribution in the total region and within the region of interest. Results show that noise is substantially reduced in the low frequency range accompanied with some reduction at the higher frequencies as well. Results also show that applied forces based on partial area control have more potential in reducing noise within the region of interest than those based on global area control. It was also observed that this control strategy performs better in vibration induced noise problems than in monopole source problems. The proposed model can be applied to noise control problems involving the transmission of vibratory energy into a cavity through fluid-structural coupling that relates structural vibration to cavity acoustics.
Modeling High-Frequency Tire Tread Vibration as a Group of Traveling Bending Waves
Authors: Ishihama Masao , Kagaya Takayuki
Published: September 2013

Tire noise is one of the major causes of road traffic noise. The high-frequency component dominates tire radiation noise, which is caused by tire tread bending vibration excited by rough road surface textures. As a result of such complicated phenomena, including very complicated tread vibration modes in the high-frequency range, heavy damping, and non-periodic patterns of the road surface texture, the modal analysis approach may appear to have a low potential for analyzing this problem. Based on the above considerations, we attempted to model the tread vibration phenomenon as a group of traveling bending waves excited at an array of pavement chippings. By setting the tread shoulders as reflecting lines, the interference effect of diagonally propagating direct and reflected waves is clarified. The vibration propagation speed and decay rate were estimated through shaker tests. The shape of the probability distribution function of the chippings intervals affects the traveling wave patterns. These observations will help engineers to develop less noisy tires.
Parallel Boundary Element Solutions of Block Circulant Linear Systems for Acoustic Radiation Problems With Rotationally Symmetric Boundary Surfaces
Authors: Czuprynski Kenneth D. , Fahnline John B. , Shontz Suzanne M.
Published: September 2013

We propose a distributed parallel algorithm for the solution of block circulant linear systems arising from acoustic radiation problems with rotationally symmetric boundary surfaces. When large structural acoustics problems are solved using a coupling finite element/boundary element formulation, the most time consuming part of the analysis is the solution of the linear system of equations for the boundary element computation. In general, the problem is solved frequency by frequency, and the coefficient matrix for the boundary element analysis is fully populated and exhibits no exploitable structure. This typically limits the number of acoustic degrees of freedom to 10–20 thousand. Because acoustic boundary element calculations require approximately six elements per wavelength to produce accurate solutions, the formation is limited to relatively low frequencies. However, when the outer surface of the structure is rotationally symmetric, the system of linear equations becomes block circulant. Building upon a known inversion formula for block circulant matrices, a parallel algorithm for the efficient solution of linear systems arising from acoustic radiation problems with rotationally symmetric boundary surfaces is developed. We show through a runtime, speedup, and efficiency analysis that the reductions in computation time are significant for an increasing number of processors.
Modeling Acoustic Properties of Different Types of Lightweight T-Junctions
Authors: Sjöström Anders , Negreira Montero Juan , Bard Delphine
Published: September 2013

To accurately model the effect on the dynamic behavior of a floor when using glue in the joints between the chipboards and beams in a lightweight structure can be a daunting task. It is however important to have a model that can simulate these junctions with high fidelity. The behavior of T-junctions with different geometries and methods of adhesion has been previously investigated via measurements [1]. This investigation builds on that work and aims at developing an accurate finite element model of the junctions. The previously investigated junctions were made of chipboards fixed to a spruce beam using screws or a combination of screws and glue. The boards were either a single plate or two plates meeting each other on top of the beam. In this investigation different approaches of simulating the junction using the finite element method were tried. The validity of the FE models was evaluated by calibrating them with previous performed measurements in [1]. A parameter study was also performed on the models to investigate the effect of the glue on the overall performance of the structure.
Prediction of High Frequency Sonic Boom Noise Transmission Into Buildings Using a Hybrid Analytical-Ray Tracing Approach
Authors: Corcoran Joseph M. , Remillieux Marcel C. , Burdisso Ricardo A.
Published: September 2013

As part of the effort to renew commercial supersonic flight, a predictive numerical tool to compute sonic boom transmission into buildings is under development. Due to the computational limitations of typical numerical methods used at low frequencies (e.g. Finite Element Method), it is necessary to develop a separate approach for the calculation of acoustic transmission and interior radiation at high frequencies. The high frequency approach can then later be combined with a low frequency method to obtain full frequency vibro-acoustic responses of buildings. An analytical method used for the computation of high frequency acoustic transmission through typical building partitions is presented in this paper. Each partition is taken in isolation and assumed to be infinite in dimension. Using the fact that a sonic boom generated far from the structure will approximate plane wave incidence, efficient analytical solutions for the vibration and acoustic radiation of different types of partitions are developed. This is linked to a commercial ray tracing code to compute the high frequency interior acoustic response and for auralization of transmitted sonic booms. Acoustic and vibration results of this high frequency tool are compared to experimental data for a few example cases demonstrating its efficiency and accuracy.
Development of Bio-Based Foams With Improved Acoustic and Mechanical Performance
Authors: Mosanenzadeh Shahrzad Ghaffari , Naguib Hani E. , Park Chul B. , Atalla Noureddine
Published: September 2013

Interest in noise control has been growing in recent years and efforts are under way to improve the acoustic performance of existing sound absorbers and also to replace the non-recyclable ones with environmentally friendly materials. Present study describes the research on fabrication, improvement of acoustic absorption and enhancement of mechanical strength of bio-based open-cell foams. Through this study, highly porous open-cell Polylactide (PLA) foams were fabricated by a new fabrication method combining particulate leaching technique and compression molding.

Foamed structures were fabricated with PLA and Polyethylene glycol (PEG) with salt as the particulate. Pore size of the foam was controlled by salt particulates and higher interconnectivity was achieved by the co-continuous blending morphology of PLA matrix with water-soluble PEG. As a result of novel secondary porous structure, acoustic performance of PLA foams was successfully improved.

One issue with application of bio-based open-cell foams is the weak structure. To improve mechanical characteristics of PLA foams, different polymer composites of PLA and Polyhydroxyalkanoate (PHA) were foamed and characterized in terms of acoustic performance, mechanical properties and foam morphology.

Polymers used in this study are bio-based which is of great importance considering huge amount of foams used as acoustic absorbers in various industries.
Influence of Blade Solidity on Marine Hydrokinetic Turbines
Authors: Jonson Michael , Fahnline John , Johnson Erick , Barone Matthew , Fontaine Arnold
Published: September 2013

Marine hydrokinetic (MHK) devices are currently being considered for the generation of electrical power in marine tidal regions. Turbulence generated in the boundary layers of these channels interacts with a turbine to excite the blades into low-to mid-frequency vibration. Additionally, the self-generated turbulent boundary layer on the turbine blade excites its trailing edge into vibration. Both of these hydrodynamic sources generate radiated noise. Being installed in a marine ecosystem, the noise generated by these MHK devices may affect the fish and marine mammal well-being. Since this MHK technology is relatively new, much of the design practice follows that from conventional horizontal axis wind turbines. In contrast to other underwater turbomachines like conventional merchant ships that have solid blades, wind turbine blades are made of hollow fiberglass composites. This paper systematically investigates the contrast of this design detail on the blade vibration and radiated noise for a particular MHK turbine design.
Preamplifier With Ultra Low Frequency Cutoff for Infrasonic Condenser Microphone
Authors: Kinnerup Rasmus Trock , Knott Arnold , Thomsen Ole Cornelius , Marbjerg Kresten , Rasmussen Per
Published: September 2013

Measuring infrasonic sound sets high requirements on the instruments used. Typically the measurement chain consists of a microphone and a preamplifier. As the input resistance of the preamplifier forms a high pass filter with the capacitance of the microphone in the picofarad range, measuring ultra low frequencies becomes a challenge. The electric preamplifier presented in this paper together with a prepolarized condenser microphone form a measurement system. The developed preamplifier connects the microphone signal directly to the input of an operational amplifier with ultra high input impedance. The bias current for the preamplifier further complicates the signal amplification. A configuration of two diode-connected FETs provide the input bias current. The resulting input impedance of nearly 1 TΩ yields a total lower limiting −3 dB cutoff frequency of 8 mHz and a dynamic range of 95 dB. Being able to measure down to ultra low frequencies in the infrasonic frequency range will aid actors in the debate on wind turbine noise. Sonic booms from supersonic flights include frequencies down to 10 mHz and the preamplifier proposed in this paper will aid scientists trying to modify the N-shaped shock wave at high level which prohibits flights in land zones.
Characterization of a clinical unit for digital radiography based on irradiation side sampling technology
Authors: Rivetti Stefano , Lanconelli Nico , Bertolini Marco , Nitrosi Andrea , Burani Aldo
Published: September 2013

Purpose:

A characterization of a clinical unit for digital radiography (FUJIFILM FDR D‐EVO) is presented. This system is based on the irradiation side sampling (ISS) technology and can be equipped with two different scintillators: one traditional gadolinium‐oxysulphide phosphor (GOS) and a needle structured cesium iodide (CsI) phosphor panel.

Methods:

The characterization was achieved in terms of response curve, modulation transfer function (MTF), noise power spectra (NPS), detective quantum efficiency (DQE), and psychophysical parameters (contrast‐detail analysis with an automatic reading of CDRAD images). For both scintillation screens the authors accomplished the measurements with four standard beam conditions: RAQ3, RQA5, RQA7, and RQA9.

Results:

At the Nyquist frequency (3.33 lp/mm) the MTF is about 35% and 25% for CsI and GOS detectors, respectively. The CsI scintillator has better noise properties than the GOS screen in almost all the conditions. This is particularly true for low‐energy beams, where the noise for the GOS system can go up to a factor 2 greater than that found for CsI. The DQE of the CsI detector reaches a peak of 60%, 60%, 58%, and 50% for the RQA3, RQA5, RQA7, and RQA9 beams, respectively, whereas for the GOS screen the maximum DQE is 40%, 44%, 44%, and 35%. The contrast‐detail analysis confirms that in the majority of cases the CsI scintillator is able to provide improved outcomes to those obtained with the GOS screen.

Conclusions:

The limited diffusion of light produced by the ISS reading makes possible the achievement of very good spatial resolution. In fact, the MTF of the unit with the CsI panel is only slightly lower to that achieved with direct conversion detectors. The combination of very good spatial resolution, together with the good noise properties reached with the CsI screen, allows achieving DQE on average about 1.5 times greater than that obtained with GOS. In fact, the DQE of unit equipped with CsI is comparable to the best alternative methods available which are based on the same technology, and similar to others based on an a‐Se direct conversion detectors.
A slice‐to‐volume registration method based on real‐time magnetic resonance imaging for measuring three‐dimensional kinematics of the knee
Authors: Lin Cheng‐Chung , Zhang Shuo , Frahm Jens , Lu Tung‐Wu , Hsu Chao‐Yu , Shih Ting‐Fang
Published: September 2013

Purpose:

This study developed and assessed a slice‐to‐volume registration method that integrated three‐dimensional (3D) static MRI volumes of the bones with a novel single‐slice, real‐time radial fast low‐angle shot MRI for measuring the 3D kinematics of the knee.

Methods:

Multislice 3D images (for establishing bone models) and 2D real‐time images of the knee at five static positions, and 2D real‐time images of the knee during flexion/extension were acquired from three healthy adults. The 3D bone poses, and thus the 3D kinematics of the knee, were obtained by registering the real‐time images to a reformed slice interpolated from the bone models according to theWEMS similarity measure. The ensemble means (biases) and standard deviations (precisions) of the measurement errors of the proposed measurement method, i.e., differences between the 3D images and the registered poses, were calculated across all the static trials of all subjects. Ensemble standard deviations of all the repeated registrations for the dynamic data of all subjects were obtained to indicate the repeatability of the registration method.

Results:

The ensemble means (standard deviations) of the measurement errors of the femoral poses were less than 0.6 (0.6) mm for translations and −0.2° (1.3°) degrees for rotations. The corresponding values for the tibia were 0.5 (0.7) mm and −0.4° (1.1°), respectively. The ensemble means (standard deviations) of the measurement errors of knee joint poses were less than 0.9 (1.4) mm for translations and −0.3° (1.8°) degrees for rotations. For registration repeatability of dynamic tests, the ensemble standard deviations were all less than 1.2 mm for translations and 1.5° for rotations.

Conclusions:

With the accuracy and repeatability achieved, and without the use of ionizing radiation and multiple repetitive motions, the proposed method combining the novel real‐time MR imaging promises to be a valuable tool for studying 3D knee kinematics noninvasively.
The Scaffold Protein Prohibitin Is Required for Antigen-Stimulated Signaling in Mast Cells
Authors: Kim Do Kyun , Kim Hyuk Soon , Kim A-Ram , Jang Geun Hyo , Kim Hyun Woo , Park Young Hwan , Kim Bokyung , Park Yeong Min , Beaven Michael A. , Kim Young Mi , Choi Wahn Soo
Published: September 2013

Targeting a scaffold protein delivered by intracellular granules in mast cells may inhibit allergic responses.
Ajuba Family Proteins Link JNK to Hippo Signaling
Authors: Sun Gongping , Irvine Kenneth D.
Published: September 2013

An evolutionarily conserved family of proteins links pathways to promote cell proliferation in response to cell death or injury.
A Role for Prohibitin in Mast Cell Activation: Location Matters
Authors: Yurugi Hajime , Rajalingam Krishnaraj
Published: September 2013

The protein prohibitin mediates receptor-proximal events to stimulate antigen-dependent degranulation of mast cells.
From Moles to Melanoma
Authors: Gough Nancy R.
Published: September 2013

Genetic variants of the melanocortin-1 receptor fail to protect PTEN from destruction, enabling excessive proliferative and survival signaling.
Vaccination with
Leishmania
Hemoglobin Receptor–Encoding DNA Protects Against Visceral Leishmaniasis
Authors: Guha Rajan , Gupta Deepika , Rastogi Ruchir , Vikram Rajagopal , Krishnamurthy Ganga , Bimal Sanjiva , Roy Syamal , Mukhopadhyay Amitabha
Published: September 2013

Hemoglobin receptor is a vaccine candidate against visceral leishmaniasis
.
A Molecular Signature Predictive of Indolent Prostate Cancer
Authors: Irshad Shazia , Bansal Mukesh , Castillo-Martin Mireia , Zheng Tian , Aytes Alvaro , Wenske Sven , Le Magnen Clémentine , Guarnieri Paolo , Sumazin Pavel , Benson Mitchell C. , Shen Michael M. , Califano Andrea , Abate-Shen Cory
Published: September 2013

A three-gene panel derived from mechanistic models of cell senescence predicts outcome of low Gleason score prostate tumors.
From Dissecting Cadavers to Dissecting Genomes
Authors: Topol Eric J.
Published: September 2013

Only when medical education mandates that students annotate whole-genome sequences will future physicians be capable of rendering routine genomic medicine.
A young 20-year-old woman with an atypical tuberculin reaction
Authors: Khan Umar H , Koul Parvaiz A
Published: September 2013

A 20-year-old female patient presented with fever and swelling in the neck accompanied by anorexia and weight loss. The clinical examination revealed a febrile patient with diffuse cervical lymphadenopathy. Routine investigations were negative. A 5TU (tuberculin units) tuberculin skin test (Mantoux test) was positive with an induration of 52×40 mm after 72 h with central blistering, exudation and ulceration. Aspiration cytology from the cervical lymph node revealed the presence of caseating granulomas. The patient responded completely to antitubrecular therapy. Enhanced-tuberculin reactions may occur on occasion in tuberculosis.
Renal aspergillosis secondary to renal intrumentation in immunocompetent patient
Authors: Paul Sagorika , Singh Viswajeet , Sankhwar Satyanarayan , Garg Manish
Published: September 2013

Primary renal aspergillosis is a rare urological entity and immune-compromised persons are commonly prone to it. The clinical presentation resembles that of usual bacterial pyelonephritis. We report a case of localised unilateral renal aspergillosis with obstructive uropathy (hypoplastic contralateral kidney) in a young man, occurring after the endoscopic removal of impacted right upper ureteric calculus in a non-immunocompromised patient. In view of deranged renal function, he was initially managed by percutaneous nephrostomy and DJ stent removal followed by oral voriconazole therapy for 3 weeks. He responded well to the treatment. Subsequently, the patient was free of renal colic, fever and urine culture negative forAspergillus.
Stretching the indications: high tibial osteotomy used successfully to treat isolated ankle symptoms
Authors: Elson David W , Paweleck James E , Shields David W , Dawson Matthew J , Ferrier Gail M
Published: September 2013

High tibial osteotomy (HTO) is successful in treating symptomatic varus arthritis of the knee. We present a case where ankle pain and instability were attributed to varus ankle malalignment. This was found to be secondary to constitutional varus of the proximal tibia but the patient's knee was asymptomatic. The decision to operate on an asymptomatic knee in the hope of improving ankle symptoms took a period of careful consideration, planning and discussion. HTO was performed without immediate complication and the patient reported an excellent outcome with marked improvement in Mazur's foot and ankle score from 18 to 85. In well selected and planned cases, HTO may be considered as an instrument of deformity correction with improvement in symptoms from joints distant to the surgical site.
Robotic-arm stereotactic radiosurgery as a definitive treatment for gelastic epilepsy associated with hypothalamic hamartoma
Authors: Susheela Sridhar Papaiah , Revannasiddaiah Swaroop , Mallarajapatna Govindarajan J , Basavalingaiah Ajaikumar
Published: September 2013

Gelastic seizures, characterised by paroxysms of pathological laughter, are most often associated with an underlying hypothalamic hamartoma. This report describes the definitive treatment using stereotactic-radiosurgery for a teenaged child whose gelastic epilepsy was found refractory to various antiepileptic drugs. Since surgery was not consented to, the child was referred to us for stereotactic radiosurgery (SRS), which was delivered with robotic-arm -SRS to a dose of 30 Gy in five fractions in five consecutive days. A decrease in the frequency of seizures was noticeable as early as within a week, and at 12 months after the procedure, there has been a total cessation of seizures.
Shaking head means “no”
Authors: Weiler Stefan , Offinger Alexander , Exadaktylos Aristomenis K
Published: September 2013

A 45-year-old man was admitted to the emergency department because of twitching of the head. The patient took a tablet of sumatriptan every 3–4 h because of increasing head pain after a car accident. Owing to depression, the patient was on long-term treatment with venlafaxine. The patient presented as hypertensive, tachycardic, with dyskinesia and spontaneous myoclonic movements of the right sternocleidomastoid muscle. In a CT scan of the head and cervical spine any fractures, bleeding or damage of the vessels after the accident could be ruled out. After discontinuation of all serotonergic agents, administration of lorazepam symptoms resolved 24 h after the last intake of sumatriptan. Serotonin syndrome is a clinical diagnosis, which requires a high-index of diagnostic suspicion. Clinical features include a broad spectrum of symptoms ranging from mild to life-threatening manifestations. Management is based on removal of precipitating drugs and symptomatic care including benzodiazepines.
Colorectal cancer survival in the USA and Europe: a CONCORD high-resolution study
Authors: Allemani Claudia , Rachet Bernard , Weir Hannah K , Richardson Lisa C , Lepage Côme , Faivre Jean , Gatta Gemma , Capocaccia Riccardo , Sant Milena , Baili Paolo , Lombardo Claudio , Aareleid Tiiu , Ardanaz Eva , Bielska-Lasota Magdalena , Bolick Susan , Cress Rosemary , Elferink Marloes , Fulton John P , Galceran Jaume , Góźdź Stanisław , Hakulinen Timo , Primic-Žakelj Maja , Rachtan Jadwiga , Diba Chakameh Safaei , Sánchez Maria-José , Schymura Maria J , Shen Tiefu , Tagliabue Giovanna , Tumino Rosario , Vercelli Marina , Wolf Holly J , Wu Xiao-Cheng , Coleman Michel P
Published: September 2013

Objectives

To assess the extent to which stage at diagnosis and adherence to treatment guidelines may explain the persistent differences in colorectal cancer survival between the USA and Europe.

Design

A high-resolution study using detailed clinical data on Dukes’ stage, diagnostic procedures, treatment and follow-up, collected directly from medical records by trained abstractors under a single protocol, with standardised quality control and central statistical analysis.

Setting and participants

21 population-based registries in seven US states and nine European countries provided data for random samples comprising 12 523 adults (15–99 years) diagnosed with colorectal cancer during 1996–1998.

Outcome measures

Logistic regression models were used to compare adherence to ‘standard care’ in the USA and Europe. Net survival and excess risk of death were estimated with flexible parametric models.

Results

The proportion of Dukes’ A and B tumours was similar in the USA and Europe, while that of Dukes’ C was more frequent in the USA (38% vs 21%) and of Dukes’ D more frequent in Europe (22% vs 10%). Resection with curative intent was more frequent in the USA (85% vs 75%). Elderly patients (75–99 years) were 70–90% less likely to receive radiotherapy and chemotherapy. Age-standardised 5-year net survival was similar in the USA (58%) and Northern and Western Europe (54–56%) and lowest in Eastern Europe (42%). The mean excess hazard up to 5 years after diagnosis was highest in Eastern Europe, especially among elderly patients and those with Dukes’ D tumours.

Conclusions

The wide differences in colorectal cancer survival between Europe and the USA in the late 1990s are probably attributable to earlier stage and more extensive use of surgery and adjuvant treatment in the USA.

Elderly patients with colorectal cancer received surgery, chemotherapy or radiotherapy less often than younger patients, despite evidence that they could also have benefited.
Sex work and HIV in Cambodia: trajectories of risk and disease in two cohorts of high-risk young women in Phnom Penh, Cambodia
Authors: Page Kimberly , Stein Ellen , Sansothy Neth , Evans Jennifer , Couture Marie-Claude , Sichan Keo , Cockroft Melissa , Mooney-Somers Julie , Phlong Pisith , Kaldor John , Maher Lisa ,   on behalf of the Young Women's Health Study Collaborative*
Published: September 2013

Objectives

HIV prevalence among Cambodian female sex workers (FSW) is among the highest in Southeast Asia. We describe HIV prevalence and associated risk exposures in FSW sampled serially in Phnom Penh, Cambodia (Young Women's Health Study (YWHS)), before and after the implementation of a new law designed to combat human trafficking and sexual exploitation.

Design

Cross-sectional analysis of baseline data from two prospective cohorts.

Setting

Community-based study in Phnom Penh, Cambodia.

Participants

Women aged 15–29 years, reporting ≥2 sexual partners in the last month and/or engaged in transactional sex in the last 3 months, were enrolled in the studies in 2007 (N=161; YWHS-1), and 2009 (N=220; YWHS-2) following information sessions where 285 and 345 women attended.

Primary outcomes

HIV prevalence, sexual risk behaviour, amphetamine-type stimulant (ATS) and alcohol use, and work-related factors were compared in the two groups, enrolled before and after implementation of the new law.

Results

Participants in the two cohorts were similar in age (median 25 years), but YWHS-2 women reported fewer sex partners, more alcohol use and less ATS use. A higher proportion of YWHS-2 compared with YWHS-1 women worked in entertainment-based venues (68% vs 31%, respectively). HIV prevalence was significantly lower in the more recently sampled women: 9.2% (95% CI 4.5% to 13.8%) vs 23% (95% CI 16.5% to 29.7%).

Conclusions

Sex work context and risk have shifted among young FSW in Phnom Penh, following implementation of anti-prostitution and anti-trafficking laws. While both cohorts were recruited using the same eligibility criteria, more recently sampled women had lower prevalence of sexual risk and HIV infection. Women engaging more directly in transactional sex have become harder to sample and access. Future prevention research and programmes need to consider how new policies and demographic changes in FSW impact HIV transmission.
Trajectories of recovery among homeless adults with mental illness who participated in a randomised controlled trial of Housing First: a longitudinal, narrative analysis
Authors: Patterson Michelle L , Rezansoff Stefanie , Currie Lauren , Somers Julian M
Published: September 2013

Objectives

This study used longitudinal, narrative data to identify trajectories of recovery among homeless adults with mental illness alongside the factors that contribute to positive, negative, mixed or neutral trajectories over time. We expected that participants who received Housing First (HF) would describe more positive trajectories of recovery than those who were assigned to Treatment as Usual (TAU; no housing or support provided through the study).

Design

Narrative interview data were collected from participants at baseline and 18 months after random assignment to HF or TAU.

Setting

Participants were sampled from the community in Vancouver, British Columbia.

Participants

Fifty-four participants were randomly and purposively selected from the larger trial; 52 were interviewed at baseline and 43 were reinterviewed 18 months after randomisation.

Method

Semistructured interviews were conducted at both time points. For each participant, paired baseline and follow-up narratives were classified as positive, negative, mixed or neutral trajectories of recovery, and thematic analysis was used to identify the factors underlying different trajectories.

Results

Participants assigned to HF (n=28) were generally classified as positive or mixed trajectories; those assigned to TAU (n=15) were generally classified as neutral or negative trajectories. Positive trajectories were characterised by a range of benefits associated with good-quality, stable housing (eg, reduced substance use, greater social support), positive expressions of identity and the willingness to self-reflect. Negative, neutral and mixed trajectories were characterised by hopelessness (‘things will never get better’) related to continued hardship (eg, eviction, substance use problems), perceived failures and loss.

Conclusions

HF is associated with positive trajectories of recovery among homeless adults with mental illness. Those who did not receive housing or support continued to struggle across a wide range of life domains. Findings are discussed with implications for addressing services and broader social change in order to benefit this marginalised population.
Long-term sustained remission in a cohort study of patients with rheumatoid arthritis: choice of remission criteria
Authors: Svensson Björn , Andersson Maria L E , Bala Sidona-Valentina , Forslind Kristina , Hafström Ingiäld ,   on behalf of the BARFOT study group
Published: September 2013

Objectives

Remission is a widely accepted goal for treatment of rheumatoid arthritis (RA) but has to be sustained to arrest joint damage and disability. However, appropriate criteria for the assessment of sustained remission in long-term studies are not established. Therefore, we have compared the disease activity score calculated on 28 joints (DAS28) remission criterion, the Simplified Disease Activity Index less than 3.3 remission criterion (SDAI Cr) and the new Boolean-based set of criteria (Boolean Cr), and assessed the association of these criteria with radiographic and functional outcome.

Design

Prospective, long-term observational study of patients with early RA.

Setting

Secondary level of care; six participating centres from southern Sweden; both urban and rural populations.

Participants

698 patients were consecutively included in the study and 527 remained at the 8-year follow-up visit. Almost all patients were Caucasians, of which 64% were women. To be included, a patient, 18 years or older, had to fulfil the 1987 American College of Rheumatology criteria for RA and have a disease duration of no more than 1 year.

Results

Sustained remission was most common by the DAS28 Cr (14%), while 3% met the Boolean Cr and 5% the SDAI Cr, the latter figures increasing to 9% and 8%, respectively, when the patient’s global assessment was excluded. Radiographic joint damage was common but least pronounced in patients in sustained remission by all criteria. Sustained remission was associated with rapid and lasting improvement in function assessed by the Health Assessment questionnaire, irrespective of criteria.

Conclusions

The DAS28 Cr acquired more patients in sustained remission compared with the other criteria. In spite of that, radiographic damage and disability were not worse than that seen by other criteria and the patients’ perspective was preserved. The DAS28 Cr may therefore still be used in long-term observational studies until more accurate criteria are available.
Offering fragile X syndrome carrier screening: a prospective mixed-methods observational study comparing carrier screening of pregnant and non-pregnant women in the general population
Authors: Martyn M , Anderson V , Archibald A , Carter R , Cohen J , Delatycki M , Donath S , Emery J , Halliday J , Hill M , Sheffield L , Slater H , Tassone F , Younie S , Metcalfe S
Published: September 2013

Introduction

Fragile X syndrome (FXS) is the leading cause of inherited intellectual and developmental disability. Policy development relating to carrier screening programmes for FXS requires input from large studies examining not only test uptake but also psychosocial aspects. This study will compare carrier screening in pregnant and non-pregnant populations, examining informed decision-making, psychosocial issues and health economics.

Methods and Analysis

Pregnant and non-pregnant women are being recruited from general practices and obstetric services. Women receive study information either in person or through clinic mail outs. Women are provided pretest counselling by a genetic counsellor and make a decision about testing in their own time. Data are being collected from two questionnaires: one completed at the time of making the decision about testing and the second 1 month later. Additional data are gathered through qualitative interviews conducted at several time points with a subset of participating women, including all women with a positive test result, and with staff from recruiting clinics. A minimum sample size of 500 women/group has been calculated to give us 88% power to detect a 10% difference in test uptake and 87% power to detect a 10% difference in informed choice between the pregnant and non-pregnant groups. Questionnaire data will be analysed using descriptive statistics and multivariate logistic regression models. Interview data will be thematically analysed. Willingness-to-pay and cost effectiveness analyses will also be performed. Recruitment started in July 2009 and data collection will be completed by December 2013.

Ethics and Dissemination

Ethics approval has been granted by the Universities of Melbourne and Western Australia and by recruiting clinics, where required. Results will be reported in peer-reviewed publications, conference presentations and through a websitehttp://www.fragilexscreening.net.au. The results of this study will make a significant contribution to discussions about the wider introduction of population carrier screening for FXS.