bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficacy of epidural lidocaine combined with tramadol or neostigmine on perineal analgesia in the horse
Authors: Derossi R. , Módolo T. J. C. , Maciel F. B. , Pagliosa R. C.
Published: August 2012

Reasons for performing study

Short duration of analgesia is among the limitations of a single epidural injection with lidocaine in horses.

Objectives

To evaluate the effectiveness and safety of epidural lidocaine in combination with either tramadol or neostigmine for perineal analgesia in horses.

Methods

Epidural catheters were placed in 6 saddle horses that then were given 3 treatments: 2% lidocaine (0.2 mg/kg bwt) alone, 2% lidocaine (0.2 mg/kg bwt) plus tramadol (0.5 mg/kg bwt), and 2% lidocaine (0.2 mg/kg bwt) plus neostigmine (1.0 μg/kg bwt). The order of treatments was randomised. Haemodynamic variables, respiratory rate, rectal temperature, analgesia, motor block and behaviour scores were compared among the 3 treatments. These parameters were determined before drug administration (baseline), at 5, 10, 15, 30, 45, 60, 75 and 90 min, and every 30 min thereafter until loss of analgesia.

Results

Duration of analgesia was longer with lidocaine plus tramadol (210 ± 12 min) compared with lidocaine plus neostigmine (150 ± 35 min) or lidocaine alone (70 ± 12 min; P<0.05). All treatments produced mild or moderate motor block without behavioural changes. Other adverse effects were not observed in any of the horses.

Conclusion and potential relevance

Further studies are required to demonstrate whether tramadol or neostigmine have a role in the management of post operative pain when coadministered with lidocaine.
Utilization patterns of antiepileptic drugs among adult epileptic patients at a tertiary hospital in Oman
Authors: Al Za'abi Mohammed , Ahmed Rowayda , Al Asmi Abdullah , Al-Zakwani Ibrahim
Published: August 2012

Objectives

To describe utilization patterns of antiepileptic drugs (AEDs) among adult epileptic patients at a tertiary hospital in Oman.

Methods

Data were collected retrospectively from January 2006 to December 2009. The study included all adult (>18 years) epileptic patients on AEDs and followed up at a neurology clinic at Sultan Qaboos University Hospital in Oman. All reported therapeutic drug monitoring (TDM) requests for serum AED concentrations were also collected. Institutional ethical approval was sought and obtained.

Key findings

The study included a total of 372 patients with a mean age of 34 ± 15 years. Monotherapy AEDs accounted for 53% of the prescriptions, whereas polytherapy with two or three AED combinations accounted for 27% and 20% respectively. The most frequently prescribed AED was sodium valproate (27%) followed by carbamazepine (23%). The commonly prescribed AED combinations were sodium valproate with clonazepam (12%) followed by sodium valproate with lamotrigine (12%). Evaluation of 574 TDM requests for three AEDs showed that 57% of carbamazepine, 78% of phenytoin and 54% of valproic acid requests were either above or below the recommended therapeutic threshold. Most of these requests were ordered from the hospital's emergency department for suspected insufficient serum concentrations.

Conclusions

Antiepileptic drug monotherapy is still the most frequently employed therapeutic strategy in adult patients with epilepsy in keeping with the standard therapeutic guidelines. Sodium valproate is commonly used for different types of seizures reflecting its wide spectrum of anticonvulsant potential. Newer AED utilizations are becoming increasingly popular in our subjects particularly as add-on with other standard AEDs.
Mendelian randomization suggests non‐causal associations of testosterone with cardiometabolic risk factors and mortality
Authors: Haring R. , Teumer A. , Völker U. , Dörr M. , Nauck M. , Biffar R. , Völzke H. , Baumeister S. E. , Wallaschofski H.
Published: August 2012

Prospective studies showed that low serum testosterone concentrations are associated with various cardiometabolic risk factors and mortality. However, the causal nature of these associations is controversial. We studied 1 882 men aged 20–79 years with serum testosterone concentrations and genotyping data from the longitudinal population‐based Study of Health in Pomerania. Testosterone concentrations were cross‐sectionally associated with cardiometabolic risk factors, including anthropometric, lipid, blood pressure and glycaemic parameters; and prospectively with all‐cause mortality (277 deaths, 14.7%) during the 10‐year follow‐up. To overcome problems of residual confounding, reverse causation, or regression dilution bias in the investigated testosterone‐outcome associations, we used two‐stage least square regression models with previously identified polymorphisms at the SHBG gene (rs12150660) and X chromosome (rs5934505) as multiple genetic instruments in an instrumental variable (IV) approach, also known as Mendelian randomization. In standard regression analyses, testosterone was robustly associated with a wide range of cardiometabolic risk factors. In subsequent IV analyses, no such significant associations were observed. Similarly, prospective analyses showed a consistent association of low testosterone concentrations with increased all‐cause mortality risk, which was not apparent in subsequent IV analyses. The present Mendelian randomization analyses did not detect any evidence for causal associations of testosterone concentrations with cardiometabolic risk factors and mortality, suggesting that previously reported associations might largely result from residual confounding or reverse causation. Although testosterone assessment might improve risk prediction, implementation of testosterone replacement therapy requires further evidence of a direct effect on cardiometabolic outcomes from double‐blinded randomized controlled trials and large‐scale Mendelian randomization meta‐analyses.
Relations of morphometric parameters to zinc content in paediatric and nonhyperplastic young adult prostate glands
Authors: Zaichick Sofia , Zaichick Vladimir
Published: August 2012

To clarify age‐related histological and zinc content changes in paediatric and nonhyperplastic young adult prostate glands, a quantitative morphometric and energy‐dispersive X‐ray fluorescence analysis (EDXRF) was performed. The prostates were obtained at autopsy from 50 subjects (European‐Caucasian aged 0–30 years) who died from sudden infant death syndrome, acute pulmonary aetiologies and trauma. None of the subjects had any symptoms of prostatic disease and all prostates were classified as histologically normal. Each prostate was divided into two portions. One tissue portion was reviewed by an anatomical pathologist whereas another was intended for a Zn mass fraction measurement using EDXRF. The mean per cent volume of the stroma (S), glandular epithelium (E), glandular lumen (L) and glandular component (GC = E + L) were determined and the mean ratios of per cent volumes (S/E, S/GC and E/L) were calculated for each prostate specimen. It was found that normal prostate tissue undergoes substantial changes from birth through early adulthood. These changes are reflected in an increment of the per cent volume of the glandular epithelium and lumen and in a diminution of the per cent volume of the stroma. The S/E ratio of the prostate falls by a factor of almost 4, between ages <1 and 30 years from 5 : 1 to 1.3 : 1. The Zn mass fraction is nearly 30–35 mg/kg (wet weight basis) and remains steady for first decade of life. Then it begins to increase rapidly during and after puberty. The level of the Zn content in prostate tissue is most closely associated with the volume of the glandular lumen, which reflects the volume of prostatic fluid.
Colorectal distension‐evoked potentials in awake rats: a novel method for studies of visceral sensitivity
Authors: Hultin L. , Nissen T. D. , Kakol‐Palm D. , Lindström E.
Published: August 2012

Background  Quantification of the visceromotor response induced by colorectal distension (CRD) in rodents is commonly used for preclinical studies of visceral pain. The model is well established but does not fully assess the central response to stimulation. The aim of this study was to establish a novel model assessing cerebral evoked potentials (CEPs) in response to CRD in awake rats.

Methods  Epidural recording electrodes were chronically implanted in the skull of female Sprague–Dawley rats. Colorectal distension‐induced CEPs were recorded using either rapid balloon distensions (100 ms, 20–80 mmHg) or electric stimulation (1 ms, 1–4 mA) using stimulation probes placed in the distal colon.

Key Results  Colorectal distension‐induced CEPs were separated in three partly temporally overlapping components consisting of five prominent peaks. Peak latencies at 80 mmHg were (P1, N1) 23 ± 1 and 55 ± 4 ms, (N2, P2a, P2b) 91 ± 3, 143 ± 5 and 174 ± 3 ms, and (P3) 297 ± 3 ms. Amplitudes and latencies were, except for the early component, intensity dependent. Intrarectal administration of lidocaine significantly reduced the amplitude of N2 (by 42 ± 6%, P < 0.001) and P2 (by 34 ± 6%, P < 0.001). Electrically induced CEPs were intensity dependent and had similar topography and latencies as the mechanical evoked potentials (P1: 26 ± 2 ms; N1: 61 ± 1 ms; P2: 84 ± 6 ms; N2: 154 ± 6 ms; P3: 326 ± 10 ms), but there were large variations in amplitudes in between repeated electrical stimulations.

Conclusions & Inferences  Colorectal distension‐induced CEPs can be recorded reliably in awake rats and may serve as a surrogate marker of colonic sensation and be a useful parameter in studies of visceral sensitivity.
Heat Transfer and Pressure Drop Measurements in a Rib Roughened Leading Edge Cooling Channel
Authors: Domaschke Norbert , von Wolfersdorf Jens , Semmler Klaus
Published: August 2012

In order to enhance convective heat transfer in internal cooling channels, ribs are often used to manipulate the flow field and to benefit from their effect on thermal performance. This paper presents results from an experimental investigation into pressure loss and heat transfer in a smooth and a ribbed leading edge channel of a gas turbine blade internal cooling system. To model the cross section of a realistic leading edge cooling channel both the suction side and the leading edge of the blade profile are designed as curved walls with constant radii. The pressure side as well as the web is approximated by planar walls. For the ribbed channel, 45 deg-ribs related to the flow direction are placed on the pressure and the suction side with the normalized rib height e/dh = 0.10. Experiments have been carried out for the smooth and the ribbed channel. The flow rate was varied to cover a Reynolds number range from 20,000 to 50,000. The heat transfer has been determined using the transient liquid crystal method. Additional numerical simulations using the SST turbulence model were carried out to analyze the flow field in the channel. The computations were used for further interpretation of the experimental investigations, especially to determine the temperature field and velocity field and therefore the bulk temperature within the test section.
Finite Element Study on the Optimization of an Orthotropic Composite Toroidal Shell
Authors: Vick Matthew J. , Gramoll Kurt
Published: August 2012

In this research, an analysis technique is developed to model orthotropic composite toroids and optimize the fiber layup, accounting for the natural variation in thickness due to fiber stacking. The behavior of toroids is difficult to model using membrane shell theories due to a singularity in the strain-displacement relations occurring at the toroid crest that yields discontinuous displacement results. A technique is developed here where the constitutive properties of multilayered toroidal shells are determined using lamination theory, and the toroid strains and line loads are determined using finite element analysis. The toroid strains are rotated into the fiber directions, allowing the fiber stress and transverse stress distributions to be determined for each layer. The fiber layup is modified heuristically until an optimum is found. An optimum is reached when the maximum fiber and transverse direction stresses of each shell layer are equal, minimizing wasted fibers and excess weight. Test cases are analyzed to verify the accuracy of the finite element model and an example composite toroid with Kevlar/epoxy material properties is optimized. The analysis technique developed here can decrease the time and cost associated with the development of orthotropic toroidal pressure vessels, resulting in lighter, cheaper, and more optimal structures. The models developed can be expanded to include a steel liner and a broader range of fiber winding patterns.
Momentum and Thermal Boundary Layer Development on an Internally Cooled Turbine Vane
Authors: Dees Jason E. , Bogard David G. , Ledezma Gustavo A. , Laskowski Gregory M. , Tolpadi Anil K.
Published: August 2012

Recent advances in computing power have made conjugate heat transfer simulations of turbine components increasingly popular; however, limited experimental data exist with which to evaluate these simulations. The primary parameter used to evaluate simulations is often the external surface temperature distribution, or overall effectiveness. In this paper, the overlying momentum and thermal boundary layers at various streamwise positions around a conducting, internally cooled simulated turbine vane were measured under low (Tu = 0.5%) and high (Tu = 20%) freestream turbulence conditions. Furthermore, experimental results were compared to computational predictions. In regions where a favorable pressure gradient existed, the thermal boundary layer was found to be significantly thicker than the accompanying momentum boundary layer. Elevated freestream turbulence had the effect of thickening the thermal boundary layer much more effectively than the momentum boundary layer over the entire vane. These data are valuable in understanding the conjugate heat transfer effects on the vane as well as serving as a tool for computational code evaluation.
Experimental Measurements and Computational Predictions for an Internally Cooled Simulated Turbine Vane With 90 Degree Rib Turbulators
Authors: Dees Jason E. , Bogard David G. , Ledezma Gustavo A. , Laskowski Gregory M. , Tolpadi Anil K.
Published: August 2012

An experimental and computational conjugate heat transfer study of an internally cooled, scaled-up simulated turbine vane with internal rib turbulators was performed. The conjugate nature of the model allowed for the effects of the internal ribs to be seen on the external overall effectiveness distribution. The enhanced internal heat transfer coefficient caused by the ribs increased the cooling capacity of the internal cooling circuit, lowering the overall metal temperature. External surface temperatures, internal surface temperatures, and coolant inlet and exit temperatures were measured and compared to data obtained from a non-ribbed model over a range of internal coolant Reynolds numbers. Internal rib turbulators were found to increase the overall effectiveness on the vane external surface by up to 50% relative to the non-ribbed model. Additionally, comparisons between the experimental measurements and computational predictions are presented.
Free-Stream Effects on the Cooling Performance of Cylindrical and Fan-Shaped Cooling Holes
Authors: Saumweber Christian , Schulz Achmed
Published: August 2012

From literature and our own studies, it is known that the effects of hot gas cross-flow and, in particular, the turbulence of the hot gas flow highly influence the spreading of the coolant in the near hole vicinity. Moreover, the velocity of the hot gas flow expressed by a hot gas Mach number obviously plays a much more important role in the case of diffuser holes than with simple cylindrical holes. To realize a certain blowing rate, a higher pressure ratio needs to be established in the case of higher Mach numbers. This in turn may strongly affect the diffusion process in the expanded portion of a fan-shaped cooling hole. The said effects will be discussed in great detail. The effects of free-stream Mach number and free-stream turbulence, including turbulence intensity, integral length scale, and periodic unsteady wake flow will be considered. The comparative study is performed by means of discharge coefficients and by local and laterally averaged adiabatic film cooling effectiveness and heat transfer coefficients. Both cooling holes have a length-to-diameter ratio of 6 and an inclination angle of 30 deg. The fan-shaped hole has an expansion angle of 14 deg. The effect of the coolant cross-flow at the hole entrance is not considered in this study, i.e., plenum conditions exist at the hole entrance.
Aerodynamic Performance of a Very High Lift Low Pressure Turbine Airfoil (T106C) at Low Reynolds and High Mach Number With Effect of Free Stream Turbulence Intensity
Authors: Michálek Jan , Monaldi Michelangelo , Arts Tony
Published: August 2012

A detailed experimental analysis of the effects of the Reynolds number and free-stream turbulence intensity on the aerodynamic performance of a very high-lift, mid-loaded low-pressure turbine blade (T106C) is presented in this paper. The study was carried out on a large scale linear cascade in the VKI S1/C high-speed wind tunnel, operating at high exit Mach number (0.65) with a range of low Reynolds numbers (80,000–160,000) and three levels of free-stream turbulence intensity (0.8–3.2%). In the first part of the paper, the overall aerodynamic performance of the airfoil is presented, based on mid-span measurements performed by means of static pressure taps, hot-film sensors and a five-hole probe traversing downstream of the cascade. Some specific features of separated flow transition are also discussed for selected cases. The second part presents the analysis of the results in terms of correlations derived for the characteristic points of boundary layer separation and transition. A comparison with some previously published prediction models is shown. The large variety of boundary conditions provides a unique database for validating codes dealing with separated flow transition in turbomachinery.
Implementing Realistic, Nonlinear, Material Stress–Strain Behavior in ANSYS for the Autofrettage of Thick-Walled Cylinders
Authors: Gibson Michael C. , Parker Anthony P. , Hameed Amer , Hetherington John G.
Published: August 2012

High-pressure vessels are autofrettaged to introduce favorable, compressive, residual stresses around their inner diameters. The efficacy of autofrettage is limited by a phenomenon called the Bauschinger effect, which describes the early onset of nonlinearity during unloading in a material that has previously been subjected to initial deformation. The degree of prestressing achieved determines the fatigue life of the vessel, hence, high fidelity prediction of the stress field developed is essential for accurate prediction of fatigue life. This requires precise representation of material behavior within the autofrettage model used. This paper describes the adaption and development of USERMAT, a user programmable feature within ANSYS (ANSYS Finite Element Program, ANSYS, Inc., Southpointe, 275 Technology Drive, Canonsburg, PA), to create a framework to represent realistic behavior of candidate gun steels. A number of materials including A723 were modeled to investigate and validate the framework. A723 was then used in simulations of both a uni-axial test and hydraulic autofrettage. These results are compared with spreadsheet data from the material-fit equations and equivalent results from the Hencky program, respectively. Close agreement was observed between the results in both cases, indicating the model is an effective means of representing the considerable variation in behavior between loading and unloading in candidate steels.
Investigation of Driving Force Variation During Swage Autofrettage, Using Finite Element Analysis
Authors: C. Gibson Michael , Hameed Amer , Hetherington John G.
Published: August 2012

Swaging is one method of autofrettage, a means of prestressing high-pressure vessels to increase their fatigue lives and load bearing capacity. Swaging achieves the required deformation through physical interference between an oversized mandrel and the bore diameter of the tube, as it is pushed along and through the bore of the tube. A finite element (FE) model of the swaging process, developed previously by the author in ANSYS, was configured for comparison with an earlier model; this allowed the accuracy of further properties of the ANSYS model to be investigated. Driving force was the main property of interest, specifically how it varied with mandrel slopes and parallel midsection, to allow direct comparison with the earlier model. The variation of driving force with respect to coefficient of friction was investigated; driving force increased in near proportion, but a subtle trend indicated a further study of stress component be made. This was followed by a two-pass swage process. Close agreement was found with empirical data and the discrepancies observed between the two models are explained by the relatively coarse mesh used by the earlier model. This further verifies the sensitivity of the model described here.
Residual Stress Measurements in an Autofrettage Tube Using Hole Drilling Method
Authors: Jahed Hamid , Faritus Mohammad Reza , Jahed Zeinab
Published: August 2012

Relieved strains due to drilling hole in a ring sample cut from an autofrettage cylinder are measured. Measured strains are then transformed to residual stresses using calibration constants and mathematical relations of elasticity based on ASTM standard recommendations (American Society for Testing and Materials, ASTM E 837-08, 2008, “Standard Test Method for Determining Residual Stresses by the Hole-Drilling Strain-Gage Method,” American Society for Testing and Materials). The hydraulic autofrettage is pressurizing a closed-end long cylinder beyond its elastic limits and subsequently removing the pressure. In contrast to three-dimensional stress state in the autofrettage tube, the stress measurement in hole drilling method is performed on a traction free surface formed from cutting the ring sample. The process of cutting the ring sample from a long autofrettaged tube is simulated using finite element method (FEM) and the redistribution of the residual stress due to the cut is discussed. Hence, transformation of the hole drilling measurements on the ring slice to the autofrettage residual stresses is revealed. The residual stresses are also predicted by variable material properties (VMP) method (Jahed, H., and Dubey, R. N., 1997, “An Axisymmetric Method of Elastic-Plastic Analysis Capable of Predicting Residual Stress Field,” Trans. ASME J. Pressure Vessel Technol., 119, pp. 264–273) using real loading and unloading behavior of the test material. Prediction results for residual hoop stress agree very well with the measurements. However, radial stress predictions are less than measured values particularly in the middle of the ring. To remove the discrepancy in radial residual stresses, the measured residual hoop stress that shows a self-balanced distribution was taken as the basis for calculating residual radial stresses using field equations of elasticity. The obtained residual stresses were improved a lot and were in good agreement with the VMP solution.
What is Hysteresis?
Authors: Morris K. A.
Published: August 2012

Hysteresis is a widely occurring phenomenon. It can be found in a wide variety of natural and constructed systems. Generally, a system is said to exhibit hysteresis when a characteristic looping behavior of the input-output graph is displayed. These loops can be due to a variety of causes. Furthermore, the input-output graphs of periodic inputs at different frequencies are generally identical. Existing definitions of hysteresis are useful in different contexts but fail to fully characterize it. In this paper, a number of different situations exhibiting hysteresis are described and analyzed. The applications described are: an electronic comparator, gene regulatory network, backlash, beam in a magnetic field, a class of smart materials and inelastic springs. The common features of these widely varying situations are identified and summarized in a final section that includes a new definition for hysteresis.
Potassium Titanyl Phosphate Laser Tissue Ablation: Development and Experimental Validation of a New Numerical Model
Authors: Elkhalil Hossam , Akkin Taner , Pearce John , Bischof John
Published: August 2012

The photoselective vaporization of prostate (PVP) green light (532 nm) laser is increasingly being used as an alternative to the transurethral resection of prostate (TURP) for treatment of benign prostatic hyperplasia (BPH) in older patients and those who are poor surgical candidates. In order to achieve the goals of increased tissue removal volume (i.e., “ablation” in the engineering sense) and reduced collateral thermal damage during the PVP green light treatment, a two dimensional computational model for laser tissue ablation based on available parameters in the literature has been developed and compared to experiments. The model is based on the control volume finite difference and the enthalpy method with a mechanistically defined energy necessary to ablate (i.e., physically remove) a volume of tissue (i.e., energy of ablation Eab). The model was able to capture the general trends experimentally observed in terms of ablation and coagulation areas, their ratio (therapeutic index (TI)), and the ablation rate (AR) (mm3/s). The model and experiment were in good agreement at a smaller working distance (WD) (distance from the tissue in mm) and a larger scanning speed (SS) (laser scan speed in mm/s). However, the model and experiment deviated somewhat with a larger WD and a smaller SS; this is most likely due to optical shielding and heat diffusion in the laser scanning direction, which are neglected in the model. This model is a useful first step in the mechanistic prediction of PVP based BPH laser tissue ablation. Future modeling efforts should focus on optical shielding, heat diffusion in the laser scanning direction (i.e., including 3D effects), convective heat losses at the tissue boundary, and the dynamic optical, thermal, and coagulation properties of BPH tissue.
Tissue Modification of the Lateral Compartment of the Tibio-Femoral Joint Following In Vivo Varus Loading in the Rat
Authors: Roemhildt M. L. , Beynnon B. D. , Gardner-Morse M. , Anderson K. , Badger G. J.
Published: August 2012

This study describes the first application of a varus loading device (VLD) to the rat hind limb to study the role of sustained altered compressive loading and its relationship to the initiation of degenerative changes to the tibio-femoral joint. The VLD applies decreased compressive load to the lateral compartment and increased compressive load to the medial compartment of the tibio-femoral joint in a controlled manner. Mature rats were randomized into one of three groups: unoperated control, 0% (sham), or 80% body weight (BW). Devices were attached to an animal’s leg to deliver altered loads of 0% and 80% BW to the experimental knee for 12 weeks. Compartment-specific material properties of the tibial cartilage and subchondral bone were determined using indentation tests. Articular cartilage, calcified cartilage, and subchondral bone thicknesses, articular cartilage cellularity, and degeneration score were determined histologically. Joint tissues were sensitive to 12 weeks of decreased compressive loading in the lateral compartment with articular cartilage thickness decreased in the peripheral region, subchondral bone thickness increased, and cellularity of the midline region decreased in the 80% BW group as compared to the 0% BW group. The medial compartment revealed trends for diminished cellularity and aggregate modulus with increased loading. The rat-VLD model provides a new system to evaluate altered quantified levels of chronic in vivo loading without disruption of the joint capsule while maintaining full use of the knee. These results reveal a greater sensitivity of tissue parameters to decreased loading versus increased loading of 80% BW for 12 weeks in the rat. This model will allow future mechanistic studies that focus on the initiation and progression of degenerative changes with increased exposure in both magnitude and time to altered compressive loads.
Localization of Viscous Behavior and Shear Energy Dissipation in Articular Cartilage Under Dynamic Shear Loading
Authors: Buckley Mark R. , Bonassar Lawrence J. , Cohen Itai
Published: August 2012

Though remarkably robust, articular cartilage becomes susceptible to damage at high loading rates, particularly under shear. While several studies have measured the local static and steady-state shear properties of cartilage, it is the local viscoelastic properties that determine the tissue's ability to withstand physiological loading regimens. However, measuring local viscoelastic properties requires overcoming technical challenges that include resolving strain fields in both space and time and accurately calculating their phase offsets. This study combined recently developed high-speed confocal imaging techniques with three approaches for analyzing time- and location-dependent mechanical data to measure the depth-dependent dynamic modulus and phase angles of articular cartilage. For sinusoidal shear at frequencies f = 0.01 to 1 Hz with no strain offset, the dynamic shear modulus |G*| and phase angle δ reached their minimum and maximum values (respectively) approximately 100 μm below the articular surface, resulting in a profound focusing of energy dissipation in this narrow band of tissue that increased with frequency. This region, known as the transitional zone, was previously thought to simply connect surface and deeper tissue regions. Within 250 μm of the articular surface, |G*| increased from 0.32 ± 0.08 to 0.42 ± 0.08 MPa across the five frequencies tested, while δ decreased from 12 deg ± 1 deg to 9.1 deg ± 0.5 deg. Deeper into the tissue, |G*| increased from 1.5 ± 0.4 MPa to 2.1 ± 0.6 MPa and δ decreased from 13 deg ± 1 deg to 5.5 deg ± 0.2 deg. Viscoelastic properties were also strain-dependent, with localized energy dissipation suppressed at higher shear strain offsets. These results suggest a critical role for the transitional zone in dissipating energy, representing a possible shift in our understanding of cartilage mechanical function. Further, they give insight into how focal degeneration and mechanical trauma could lead to sustained damage in this tissue.
Predicted Size of an Inelastic Zone in a Ball-Grid-Array Assembly
Authors: Suhir E. , Bechou L. , Levrier B.
Published: August 2012

A simple and easy-to-use analytical (“mathematical”) predictive model has been developed for the assessment of the size of an inelastic zone, if any, in a ball-grid-array (BGA) assembly. The BGA material is considered linearly elastic at the strain level below the yield point and ideally plastic above the yield strain. The analysis is carried out under the major assumptions that, as far as the estimated size of an inelastic zone is concerned, (1) the inhomogeneous (“discrete”) BGA structure can be substituted by a homogeneous (continuous) bonding layer of the same thickness (height) and (2) only the longitudinal cross-section of the package-substrate assembly can be considered. The numerical example carried out for a 30 mm long surface-mount package and a 200 μm thick lead-free solder indicated that, in the case of a high expansion PCB substrate, about 7.5% of the interface's size experienced inelastic strains, while no such strains could possibly occur in the case of a low expansion ceramic substrate. The suggested model can be used to check if the zone of inelastic strains exists in the design of interest and, if inelastic strains cannot be avoided, how large this zone is, before applying a Coffin-Manson-type of an equation (such as, say, Anand's model in the ANSYS software) with an objective to evaluate the BGA material lifetime.
Predicted Thermal Stresses in a Trimaterial Assembly With Application to Silicon-Based Photovoltaic Module
Authors: Suhir E. , Shangguan D. , Bechou L.
Published: August 2012

Low-temperature thermally induced stresses in a trimaterial assembly subjected to the change in temperature are predicted based on an approximate structural analysis (strength-of-materials) analytical (“mathematical”) model. The addressed stresses include normal stresses acting in the cross-sections of the assembly components and determining their short- and long-term reliability, as well as the interfacial shearing and peeling stresses responsible for the adhesive and cohesive strength of the assembly. The model is applied to a preframed crystalline silicon photovoltaic module (PVM) assembly. It is concluded that the interfacial thermal stresses, and especially the peeling stresses, can be rather high, so that the structural integrity of the module could be compromised, unless appropriate design for reliability measures are taken. The developed model can be helpful in the stress analysis and physical (structural) design of the PVM and other trimaterial assemblies.
Technical Note: Improved implementation of doppler broadening in MCNP5
Authors: Bartol Laura J. , DeWerd Larry A.
Published: August 2012

Purpose:

Incoherent scattering has a substantial effect on spectroscopic measurements and simulations. Many general‐purpose Monte Carlo codes include models that account for the effects of bound electrons on incoherent scattering, including Doppler broadening (DB). This work investigates the DB model used in the Monte Carlo N‐particle transport code (MCNP5).

Methods:

Simulations were run with three versions of MCNP5: v1.51, v1.60, and a modified form of v1.60 (v1.60m). All simulations used the MCPLIB04 photon data library, which presents the electron subshell data for incoherent scattering in the form of a probability density function. In v1.60m, the source code was altered to sample the electron subshell from a cumulative density function instead. Each version of the code was tested using an identical set of simulations that investigated DB in a slab of silicon at scattering angles of 15°, 30°, and 45°. For each angle, simulations were run for multiple energies between 200 keV and 800 keV. The spectrum of singly‐scattered photons at the exit of the slab was scored. Spectra were analytically calculated for comparison.

Results:

In v1.51, DB was modeled for incident photon energies below 760 keV, 384 keV, and 260 keV at scattering angles of 15°, 30°, and 45°, respectively. Above these energy thresholds, v1.51 did not model DB. The spectra calculated using v1.60 and v1.60m exhibited DB for all energy‐angle combinations; however, v1.60m, exhibited more energy broadening than did v1.60. The spectra calculated with v1.60m agreed with the analytical calculations.

Conclusions:

MCNP5 v1.51 and v1.60 model partial broadening when used with the MCPLIB04 data library. MCNP5 v1.60m models DB more accurately due to the form of the electron subshell data. In response to these results, Los Alamos National Laboratory has released a new photon data library, MCPLIB84, that presents the electron subshell data in cumulative distribution form. MCNP5 v1.60 should be used with this library when incoherent scattering has a significant impact on simulation results.
Mannose-Capped Lipoarabinomannan from Mycobacterium tuberculosis Induces Soluble Tumor Necrosis Factor Receptor Production through Tumor Necrosis Factor Alpha-Converting Enzyme Activation
Authors: Richmond Jillian M. , Duffy Elizabeth R. , Lee Jinhee , Kaboli Kavon , Remick Daniel G. , Kornfeld Hardy , Cruikshank William W.
Published: August 2012

PrimaryMycobacterium tuberculosisinfection results in granuloma formation in lung tissue. A granuloma encapsulates mycobacterium-containing cells, thereby preventing dissemination and further infection. Tumor necrosis factor alpha (TNF-α) is a host-protective cytokine duringM. tuberculosisinfection due to its role in promoting and sustaining granuloma formation. TNF activity is regulated through the production of soluble TNF receptors (sTNFRI and sTNFRII). Therefore, we examined the potential production of endogenous sTNFRs duringM. tuberculosisinfection. Using the murine model of aerosolM. tuberculosisinfection, we determined that levels of sTNFR production were elevated in bronchoalveolar lavage fluid 1 month following infection. An investigation ofM. tuberculosiscell wall components identified that the known virulence factor mannose-capped lipoarabinomannan (ManLAM) was sufficient to induce sTNFR production, with sTNFRII being produced preferentially compared with sTNFRI. ManLAM stimulated the release of sTNFRs without TNF production, which corresponded to an increase in TNF-α-converting enzyme (TACE) activity. To determine the relevance of these findings, serum samples fromM. tuberculosis-infected patients were tested and found to have an increase in the sTNFRII/sTNFRI ratio. These data identify a mechanism by whichM. tuberculosisinfection can promote the neutralization of TNF and furthermore suggest the potential use of the sTNFRII/sTNFRI ratio as an indicator of tuberculosis disease.
Congenitally missing primary mandibular lateral incisors: a case of rare occurrence
Authors: Goswami Mousumi , Chaitra TR , Singh Sanjay , Kulkarni Adwait Uday
Published: August 2012

We are reporting a rare case of missing teeth in primary dentition. The case reported with the chief complaint of missing teeth in the lower front tooth region. The concern of the parents was missing primary teeth but they were also worried about the permanent successors. Thorough evaluation of the primary dentition visually and permanent dentition radiographically was done. There was missing 72 and 82.Along with these, there were few permanent teeth, that is, lack of initiation of 35 and 45 and 22 was evident. The case was non-syndromic. At present, the case is under follow-up.
Solid-pseudopapillary carcinoma: a case study and literature review
Authors: Mat Zin Anani Aila , Shakir K A R , Aminuddin A R , Mahedzan M R , Irnawati W A R , Andee D Z , Hassan S A , Ezane M A , Hasnan M N
Published: August 2012

Solid-pseudopapillary tumour (SPT) is a rare exocrine tumour of the pancreas and is considered to have low malignant potential. Few morphological criteria are used to predict malignant behaviour such as equivocal perineural invasion, angioinvasion and invasion to surrounding tissue, and should be designated as solid-pseudopapillary carcinoma (SPC). We report a case of SPC. Clinical and radiological findings are typical for SPT with no metastatic disease. There is no tumour recurrence after 4 months postresection. Clinical history and radiological findings were retrieved from the patient's record sheet and Viarad system. H&E staining and few immunoproxidase staining were reviewed by several pathologists. The histological findings are typical for SPT, with additional perineural invasion. There is no angioinvasion or capsular invasion identified. This is our first experience in diagnosing and managing SPC. We look forward to seeing the patient's disease status during her next routine follow-up. We expect good disease-free survival and very low risk of tumour recurrence, in view of only one risk factor (perineural invasion) and uninvolved surgical margins by the tumour.
Gallbladder malakoplakia in type 2 diabetes mellitus: a rare entity
Authors: Vaiphei Kim , Singh Priya , Verma Ganga Ram
Published: August 2012

Gallbladder malakoplakia in type 2 diabetes mellitus is a rare condition. Differentiating malakoplakia, which is a more aggressive disease condition with possible genetic abnormality from a more benign but closely related condition such as xanthogranulomatous cholecystitis, is of prognostic importance in postoperative patient management and follow-up.
Genital tuberculosis with variable presentation: a series of three cases
Authors: Sachan Rekha , Patel Munna Lal , Gupta Pooja , Verma Ajay Kumar
Published: August 2012

Tuberculosis (TB) is still frequently observed in third-world countries like Africa and Asia. Here we report three cases of genital TB with variable presentation. First case was a lady of reproductive age group who presented with polymenorrhagia and postcoital bleeding with unhealthy cervix. Histopathology of cervical tissue revealed tubercular cervicitis. Second and third cases presented with different complaints like discharge per vaginum, postcoital bleeding and pain in lower abdomen with growth over the cervix. Cervical biopsy was inconclusive of TB but endometrial tissue sampling for TB PCR was positive. This shows that newer diagnostic marker test can help us to detect secondary genital TB.
Cushing syndrome associated with an adrenal tumour
Authors: Vieira Helena , Brain Caroline
Published: August 2012

Cushing syndrome (CS) in children is a rare disorder that is most frequently caused by an adrenal tumour or a pituitary corticotrophin-secreting adenoma. The management is challenging and requires an individualised approach and multidisciplinary care. We present the case of a 23-month-old female child with a history of excessive weight gain, growth failure, hirsutism, acne and behavioural difficulties. Investigations revealed elevated serum midnight cortisol and 24 h urinary free cortisol. Overnight dexamethasone suppression testing showed no suppression of cortisol levels. Abdominal imaging revealed a right-sided suprarenal mass. She underwent right adrenalectomy and the histology showed an adrenal cortical carcinoma. There was clinical improvement with catch-up growth and weight normalisation. Despite being rare in clinical practice, in a child with weight gain, hirsuitism and growth failure the diagnosis must be considered. The overall prognosis of CS in childhood is good, but challenges remain to ensure normal growth and body composition.
Participatory healthcare-provider orientation to improve artemether-lumefantrine-based drug treatment of uncomplicated malaria: a cluster quasi-experimental study
Authors: Anyama Norbert G , Tibenderana James K , Kutyabami Paul , Kamba Pakoyo F , Kitutu Freddy E , Adome Richard O
Published: August 2012

Objectives

To assess the effect of participatory healthcare-provider orientation in enhancing patient knowledge, appropriate prescribing and dispensing of artemether-lumefantrine, during drug treatment of uncomplicated malaria.

Methods

A cluster quasi-experimental study. The authors developed strategies to address challenges encountered by healthcare providers during clinical management of malaria. The primary outcome was patient knowledge on prescribed malaria drug treatment. Secondary outcomes were appropriate prescribing and provision of adequate drug dispensing information. The authors used generalised estimating equation logistic regression to investigate correlates of appropriate use of artemether-lumefantrine.

Results

The proportion of patients or caretakers of paediatric patients sufficiently knowledgeable about malaria treatment increased from 16/85 (18.8%) at baseline to 33/96 (34.4%) at evaluation, OR 2.26 (95% CI 1.13 to 4.49), p=0.020, in the intervention, and fell slightly from 49/134 (36.6%) to 35/114 (30.7%), OR 0.77, (95% CI 0.45 to 1.31), p=0.331 in the control district. This was enhanced by the existence of drug-dispensing standard operating procedures (adjusted OR 1.85, 95% CI 0.98 to 3.50; p=0.057). The proportion of appropriate prescriptions increased from 61/87 (70.1%) to 94/112 (83.9%) in the intervention district, OR 2.23 (95% CI 1.13 to 4.40), p=0.020 and reduced from 91/115 (79.1%) to 75/112 (67.0%) in the control district, OR 0.53, (95% CI 0.29 to 0.97), p=0.040. The frequency of adequately dispensed prescriptions increased in the intervention district (34(32.4%) to 53(45.3%), OR 1.73 (95% CI 1.00 to 2.99), p=0.050) but decreased in the control location (94 (69.6%) to 71 (52.6%), OR 0.48 (95% CI 0.29 to 0.80), p=0.004).

Conclusions

Participatory healthcare-provider orientation enhanced patient knowledge, healthcare provider prescribing and dispensing of artemether-lumefantrine, bolstered by adequate medication counselling and use of drug-dispensing standard operating procedures.
Predictors of likelihood of speaking up about safety concerns in labour and delivery
Authors: Lyndon Audrey , Sexton J Bryan , Simpson Kathleen Rice , Rosenstein Alan , Lee Kathryn A , Wachter Robert M
Published: August 2012

Background

Despite widespread emphasis on promoting ‘assertive communication’ by care givers as essential to patient-safety-improvement efforts, little is known about when and how clinicians speak up to address safety concerns. In this cross-sectional study, the authors use a new measure of speaking up to begin exploring this issue in maternity care.

Methods

The authors developed a scenario-based measure of clinician's assessment of potential harm and likelihood of speaking up in response to perceived harm. The authors embedded this scale in a survey with measures of safety climate, teamwork climate, disruptive behaviour, work stress, and personality traits of bravery and assertiveness. The survey was distributed to all registered nurses and obstetricians practising in two US Labour & Delivery units.

Results

The response rate was 54% (125 of 230 potential respondents). Respondents were experienced clinicians (13.7±11 years in specialty). A higher perception of harm, respondent role, specialty experience and site predicted the likelihood of speaking up when controlling for bravery and assertiveness. Physicians rated potential harm in common clinical scenarios lower than nurses did (7.5 vs 8.4 on 2–10 scale; p<0.001). Some participants (12%) indicated they were unlikely to speak up, despite perceiving a high potential for harm in certain situations.

Discussion

This exploratory study found that nurses and physicians differed in their harm ratings, and harm rating was a predictor of speaking up. This may partially explain persistent discrepancies between physicians and nurses in teamwork climate scores. Differing assessments of potential harms inherent in everyday practice may be a target for teamwork intervention in maternity care.
Preventable deaths due to problems in care in English acute hospitals: a retrospective case record review study
Authors: Hogan Helen , Healey Frances , Neale Graham , Thomson Richard , Vincent Charles , Black Nick
Published: August 2012

Introduction

Monitoring hospital mortality rates is widely recommended. However, the number of preventable deaths remains uncertain with estimates in England ranging from 840 to 40 000 per year, these being derived from studies that identified adverse events but not whether events contributed to death or shortened life expectancy of those affected.

Methods

Retrospective case record reviews of 1000 adults who died in 2009 in 10 acute hospitals in England were undertaken. Trained physician reviewers estimated life expectancy on admission, to identified problems in care contributing to death and judged if deaths were preventable taking into account patients' overall condition at that time.

Results

Reviewers judged 5.2% (95% CI 3.8% to 6.6%) of deaths as having a 50% or greater chance of being preventable. The principal problems associated with preventable deaths were poor clinical monitoring (31.3%; 95% CI 23.9 to 39.7), diagnostic errors (29.7%; 95% CI 22.5% to 38.1%), and inadequate drug or fluid management (21.1%; 95% CI 14.9 to 29.0). Extrapolating from these figures suggests there would have been 11 859 (95% CI 8712 to 14 983) adult preventable deaths in hospitals in England. Most preventable deaths (60%) occurred in elderly, frail patients with multiple comorbidities judged to have had less than 1 year of life left to live.

Conclusions

The incidence of preventable hospital deaths is much lower than previous estimates. The burden of harm from preventable problems in care is still substantial. A focus on deaths may not be the most efficient approach to identify opportunities for improvement given the low proportion of deaths due to problems with healthcare.