Compositional and Material Properties of Rat Bone after Bisphosphonate and/or Strontium Ranelate Drug Treatment

PURPOSE: We investigated elemental strontium and/or bisphosphonate drug incorporation upon the compositional and biomechanical properties of vertebral bone, in a rat model of Osteoporosis secondary to ovariectomy. METHODS: Six month old female rats were ovariectomized (OVX) and divided into untreated OVXVehicle, OVX-RIS (Risedronate bisphosphonate [BP] treated), OVX-SrR (Strontium Ranelate [Protos®] treated), combination OVX-RIS+SrR, and sham-operated controls. After 16 weeks of treatment, rats were euthanized and lumbar vertebra were dissected. Micro-Computed Tomography (micro-CT), Electron Probe Micro-Analysis (EPMA), mechanical testing in compression and nano-indentation testing were then undertaken to evaluate bone morphometry, elemental composition, material properties and strength. Results. Bone Volume was significantly reduced in the OVX-Vehicle (133±10mm3) compared with OVX-RIS (169±22mm3), OVXSrR (145±2mm3), and OVX-RIS+SrR (172±8mm3). EPMA mapped elemental Sr deposition to the periosteal surface of cortical bone (50-100 µm thick), endosteal trabecular surfaces (20 µm thick), as well as to both vertebral growth plates. The atomic ratios of (Ca+Sr)/P were significantly reduced with SrR treatment (2.4%- 6.6%), indicating Sr incorporation into bone mineral. No significant differences were measured in vertebral bone reduced modulus by nano-indentation. Conversely, all BP-dosed groups had significantly increased structural bone strength. CONCLUSIONS: Thus, we conclude that BP drugs dominate the conservation of trabecular geometry and structural strength in OP rats, whereas Sr drugs likely influence bone volume and material composition locally

Pilot reuse sequences for TDD in downlink multi-cells to improve data rates

The exponential growth in demand for high data rate transmission to users in fifth generation wireless networks, focus there has been a particular research focus on new techniques that achievable high data rate by suppressing interference between neighboring cells. In this paper, we propose that system performance can be improved by using perfect channel estimation and reducing effective interference with pilot reuse that mitigate strong pilot contamination based on the knowledge of large-scale fading coefficients. We derived the lower bounds on the achievable data rate in downlink by analyzing the performance of the zero-forcing precoding method and derive the signal-to-interference noise ratio to mitigate interference between neighboring cells. From the simulation results, the large pilot reuse sequences improved the achievable data rate and provided better estimation for a channel. When the number of users is large, the interference between neighboring cells can be suppressed by using orthogonal pilot reuse sequences

Utilizing ultrasonic energy for reduction of free fatty acids in crude palm oil

Recently, biodiesel production from abundant bio-sources has drawn the attention of the academic and the industrial community. In this study, crude palm oil (CPO) containing 8.7% free fatty acid content (FFA) was used as raw material. Different common types of acid catalysts (sulfuric acid, methanesulfonic acid and hydrochloric acid) were optimized to investigate the catalytic activity of each acid in the pre-treatment of CPO by the esterification process. Ultrasonic energy was used for the reduction of FFA in CPO. FFA content was measured at different sonication intervals, and the optimum time was determined. Hydrochloric acid showed the highest catalytic activity in the reduction of FFA content in CPO, as well as in converting FFA to fatty acid methyl ester (FAME). From this work, it is reasonable to conclude that there is significant enhancement in the pre-treatment of oils by applying ultrasonic energy using long sonication time.Keywords: Biodiesel, crude palm oil, free fatty acids, ultrasonic energ

Experimental and numerical study of strength mismatch in cross-weld tensile testing

The mechanical properties of welded boiler tubes used in power plants can be significantly altered as a result of the fabrication history, such as pre-straining and heat treatment. The primary aim of the study was to determine the effect of fabrication history on local tensile properties across the welds. This was achieved by testing cross-weld specimens machined from welded thin-walled tubes (with unstrained or pre-strained base metal) before and after heat treatment. Digital image correlation, which is a full-field strain measurement technique, was implemented in order to obtain the local stress–strain curves and to extract the corresponding local tensile properties such as offset proof stress. Evidence of strain hardening due to the constraint and thermo-mechanical cycles during the welding process was found in the heat-affected zone and evidence of softening was observed in the pre-strained base metal. It was found that the heat treatment process removed the effect of pre-straining and welding on the proof stress and the strength along the specimen was nearly homogenized. However, mapping the local stress–strain curves in the as-welded cross-weld specimens with pre-strained base metal has revealed abnormal strain relaxation with increase in load in the weld-affected region. For a better understanding of this behaviour, a tensile test of a cross-weld specimen with a large strength mismatch between the weld metal and the base metal was simulated using the finite element method. It was found that the strength mismatch in the specimen causes the development of biaxial stresses in the heat-affected zone once local yielding begins, and the use of global axial stress to construct the local stress–strain curve results in an apparent ‘reduced-strain’ anomaly. Nevertheless, for the strength mismatch ratios studied, this anomalous behaviour did not seem to significantly affect the determination of the local proof stress in the specimens

Exponential Tapered Balun with Different Sizes for UWB Elliptical Dipole Antenna

This work presents a broadband tapered balun with different sizes using nonlinear transition particularly suitable for planar and three-dimensional (3-D) dipole antennas for ultra-wideband (UWB) applications such as communication, radar systems and geolocation precision. Four baluns with wideband microstrip-to-parallel-strip transition using an elliptical structure for an elliptical dipole antenna are proposed. The initial balun structure consists of a nonlinear profile with a quarter-wavelength for both height and width. By studying the current distributions at the balun surface, it can be reduced to 25%, 50% and 75% from the original size. Measured results based on the reflection coefficients for all baluns are shown to be better than -10 dB from 1.0 GHz to 10 GHz. These baluns are integrated with an elliptical dipole which acts as a feeding circuit. Eight set of antennas with a planar and 3-D configurations with four different sizes are proposed in this work. The planar configurations are named as Planar 1, Planar 2, Planar 3 and Planar 4 while the 3-D configurations are named as 3D Dipole 1, 3D Dipole 2, 3D Dipole 3 and 3D Dipole 4, respectively. The results show that all antennas with the proposed baluns operates within the UWB frequency range

An Inductive Link-Based Wireless Power Transfer System for Biomedical Applications

A wireless power transfer system using an inductive link has been demonstrated for implantable sensor applications. The system is composed of two primary blocks: an inductive power transfer unit and a backward data communication unit. The inductive link performs two functions: coupling the required power from a wireless power supply system enabling battery-less, long-term implant operation and providing a backward data transmission path. The backward data communication unit transmits the data to an outside reader using FSK modulation scheme via the inductive link. To demonstrate the operation of the inductive link, a board-level design has been implemented with high link efficiency. Test results from a fabricated sensor system, composed of a hybrid implementation of custom-integrated circuits and board-level discrete components, are presented demonstrating power transmission of 125 mW with a 12.5% power link transmission efficiency. Simultaneous backward data communication involving a digital pulse rate of up to 10 kbps was also observed

3-D Volumetric Evaluation of Human Mandibular Growth

Bone growth is a complex process that is controlled by a multitude of mechanisms that are not fully understood.Most of the current methods employed to measure the growth of bones focus on either studying cadaveric bones from different individuals of different ages, or successive two-dimensional (2D) radiographs. Both techniques have their known limitations. The purpose of this study was to explore a technique for quantifying the three dimensional (3D) growth of an adolescent human mandible over the period of one year utilizing cone beam computed tomography (CBCT) scans taken for regular orthodontic records. Three -dimensional virtual models were created from the CBCT data using mainstream medical imaging software. A comparison between computer-generated surface meshes of successive 3-D virtual models illustrates the magnitude of relative mandible growth. The results of this work are in agreement with previously reported data from human cadaveric studies and implantable marker studies. The presented method provides a new relatively simple basis (utilizing commercially available software) to visualize and evaluate individualized 3D (mandibular) growth in vivo

3-Monochloropropane-1,2-diol (3-MCPD): a review on properties, occurrence, mechanism of formation, toxicity, analytical approach and mitigation strategy

3-Monochloropropane-1,2-diol (3-MCPD) is one of the most common food contaminants in processed oils which forms mostly during the deodorization step of edible oil refining process. It has been detected in many types of food products such as infant formula, margarine, bread and soy sauce, which could result in kidney and testicular damage. The presence of 3-MCPD contaminant have been occurring for more a decade, which warrants a maximum permissible amount of 2 µg/kg body weight in food products in national and international levels. The purpose of this review is to provide an overview in the past 12 years on its physicochemical properties, occurrence, potential precursors and formation mechanism of 3-MCPD in foodstuffs. The toxicity, its quantification methods and mitigation strategy are also reviewed with an emphasis on the applicability, efficiency and issues encountered during the analysis. This review provides an elucidation regarding 3-MCPDEs and their food safety implications

C5 Palsy After Cervical Spine Surgery: A Multicenter Retrospective Review of 59 Cases.

STUDY DESIGN: A multicenter, retrospective review of C5 palsy after cervical spine surgery. OBJECTIVE: Postoperative C5 palsy is a known complication of cervical decompressive spinal surgery. The goal of this study was to review the incidence, patient characteristics, and outcome of C5 palsy in patients undergoing cervical spine surgery. METHODS: We conducted a multicenter, retrospective review of 13 946 patients across 21 centers who received cervical spine surgery (levels C2 to C7) between January 1, 2005, and December 31, 2011, inclusive. P values were calculated using 2-sample t test for continuous variables and χ(2) tests or Fisher exact tests for categorical variables. RESULTS: Of the 13 946 cases reviewed, 59 patients experienced a postoperative C5 palsy. The incidence rate across the 21 sites ranged from 0% to 2.5%. At most recent follow-up, 32 patients reported complete resolution of symptoms (54.2%), 15 had symptoms resolve with residual effects (25.4%), 10 patients did not recover (17.0%), and 2 were lost to follow-up (3.4%). CONCLUSION: C5 palsy occurred in all surgical approaches and across a variety of diagnoses. The majority of patients had full recovery or recovery with residual effects. This study represents the largest series of North American patients reviewed to date

Correlation of Total Cholesterol and Glucose in Serum of Iraqi Patients with Atherosclerosis and Diabetes Mellitus Type 2

Cholesterol is a fatty substance (lipid) classified as a waxy steroid of fat. It is absorbed by the intestine into blood stream and is packaged inside a protein coat a chylomicron. Blood glucose is a simple monosaccharide absorbed directly into the blood stream during digestion. The level of blood glucose normally represents a balance between the inflow of glucose into blood and it is uptake by the tissue. Atherosclerosis is a general term for a number of different medical conditions that affect the heart, this is occurs when the blood supply to a part of heart is interrupted, must commonly due to plaque, is build up in the coronary arteries consist of lipid cholesterol and calcium. It causes a damage of potential disease of heart muscle due to thickening and hardening of arteries. Diabetes mellitus is a disorder in which the level of blood glucose is persistently elevated above the normal range due to decrease secretion of insulin. The main objective of this study is to determine the concentrations of total cholesterol and glucose into blood serum of Iraq patients with atherosclerosis and diabetes mellitus type 2. This study included 60 specimens of patients with atherosclerosis and 60 patients with type 2 diabetes mellitus; their age range was 45-65 years. These patients were then matched by age and sex to 30 healthy individuals. Results revealed that there was highly significantly increased in the mean value of total cholesterol and glucose concentrations in patients of atherosclerosis (p<0.001) and diabetes mellitus (p<0.001) as compared with healthy individuals