Differences of Curing Effects between a Human and Veterinary Bone Cement.

The goal of the study is to understand how the curing characteristics of a human bone cement (HBC) and veterinary bone cement (VBC) influence the mechanical behavior of each cement and cement bonding with an implant. This study hypothesizes that the curing temperature and time influence the mechanical properties of the cement adjacent to the implant, which resulted in the variability in bonding strength between the implant and cement. To test this hypothesis, this study measured the exothermic temperature, flexural strength, hardness, and morphology of a HBC and VBC at different curing times.

Center of Mass Motion of Short-Range Correlated Nucleon Pairs studied via the A(e,e^{'}pp) Reaction.

Short-range correlated (SRC) nucleon pairs are a vital part of the nucleus, accounting for almost all nucleons with momentum greater than the Fermi momentum (k_{F}). A fundamental characteristic of SRC pairs is having large relative momenta as compared to k_{F}, and smaller center of mass (c.m.

Effect of Collagen-Polycaprolactone Nanofibers Matrix Coating on the Cytocompatibility and Bone Responses of Titanium.

The objective of this study was to improve the biomechanical performance of titanium (Ti) using a biocompatible electrospun nanofiber matrix. The study is based on the hypothesis that coating a Ti surface with a nanofiber matrix (NFM) made of collagen (CG) and polycaprolactone (PCL) electrospun nanofibers could increase the mechanical fixation of Ti/bone by improving the surface and cytocompatibility properties of Ti. This study prepared Ti samples with and without CG-PCL NFM coatings.

Excitation functions of proton- and deuteron-induced nuclear reactions on natural iridium for the production of Pt.

We studied the excitation functions of residual radionuclides produced via proton and deuteron bombardment on natural iridium in the energy ranges of 30-15 MeV and 50-15 MeV, respectively. A conventional stacked-foil activation technique combined with HPGe γ-ray spectrometry was used to measure the excitation functions for Pt and Ir radionuclide production. Theoretical thick target yields were estimated to be 172 MBq/µA h and 192 MBq/µA h via the Ir(p,3n)Pt reaction at 29.

Radioluminescence sensing of radiology exposures using P-doped silica optical fibres.

In previous work we investigated the real-time radioluminescence (RL) yield of Ge-doped silica fibres and AlO nanodot media, sensing electron- and x-ray energies and intensities at values familiarly obtained in external beam radiotherapy. The observation of an appreciable low-dose sensitivity has given rise to the realisation that there is strong potential for use of RL dosimetry in diagnostic radiology. Herein use has been made of P-doped silica optical fibre, 2 mm diameter, also including a 271 µm cylindrical doped core.

Measurement of the Q^{2} Dependence of the Deuteron Spin Structure Function g_{1} and its Moments at Low Q^{2} with CLAS.

We measured the g_{1} spin structure function of the deuteron at low Q^{2}, where QCD can be approximated with chiral perturbation theory (χPT). The data cover the resonance region, up to an invariant mass of W≈1.9  GeV.

Elevated concentrations of naturally occurring radionuclides in heavy mineral-rich beach sands of Langkawi Island, Malaysia.

Study is made of the radioactivity in the beach sands of Langkawi island, a well-known tourist destination. Investigation is made of the relative presence of the naturally occurring radionuclide K and the natural-series indicator radionuclides Ra and Th, the gamma radiation exposure also being estimated. Sample quantities of black and white sand were collected for gamma ray spectrometry, yielding activity concentration in black sands of Ra, Th and K from 451±9 to 2411±65Bqkg (mean of 1478Bqkg); 232±4 to 1272±35Bqkg (mean of 718Bqkg) and 61±6 to 136±7Bqkg (mean of 103Bqkg) respectively.

Evaluation of production cross-sections for Re theranostic radionuclide via charged-particle induced reactions on Tungsten.

Re (T = 89.24 h, [Formula: see text] 346.7 keV, [Formula: see text] ), an intense beta-emitter shows great potential to be used as an active material in therapeutic radiopharmaceuticals due to its suitable physico-chemical properties.

First Exclusive Measurement of Deeply Virtual Compton Scattering off ^{4}He: Toward the 3D Tomography of Nuclei.

We report on the first measurement of the beam-spin asymmetry in the exclusive process of coherent deeply virtual Compton scattering off a nucleus. The experiment uses the 6 GeV electron beam from the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab incident on a pressurized ^{4}He gaseous target placed in front of the CEBAF Large Acceptance Spectrometer (CLAS). The scattered electron is detected by CLAS and the photon by a dedicated electromagnetic calorimeter at forward angles.

Evaluation of Electrospun Nanofiber-Anchored Silicone for the Degenerative Intervertebral Disc.

The nucleus pulposus (NP) substitution by polymeric gel is one of the promising techniques for the repair of the degenerative intervertebral disc (IVD). Silicone gel is one of the potential candidates for a NP replacement material. Electrospun fiber anchorage to silicone disc, referred as ENAS disc, may not only improve the biomechanical performances of the gel but it can also improve restoration capability of the gel, which is unknown.

Evaluation of Polyethylene Glycol Diacrylate-Polycaprolactone Scaffolds for Tissue Engineering Applications.

Polyethylene Glycol Diacrylate (PEGDA) tissue scaffolds having a thickness higher than 1 mm and without the presence of nutrient conduit networks were shown to have limited applications in tissue engineering due to the inability of cells to adhere and migrate within the scaffold. The PEGDA scaffold has been coated with polycaprolactone (PCL) electrospun nanofiber (ENF) membrane on both sides to overcome these limitations, thereby creating a functional PEGDA-PCL scaffold. This study examined the physical, mechanical, and biological properties of the PEGDA and PEGDA-PCL scaffolds to determine the effect of PCL coating on PEGDA.

Monte Carlo skin dose simulation in intraoperative radiotherapy of breast cancer using spherical applicators.

Unlabelled: The relatively new treatment modality electronic intraoperative radiotherapy (IORT) is gaining popularity, irradiation being obtained within a surgically produced cavity being delivered via a low-energy x-ray source and spherical applicators, primarily for early stage breast cancer. Due to the spatially dramatic dose-rate fall off with radial distance from the source and effects related to changes in the beam quality of the low keV photon spectra, dosimetric account of the Intrabeam system is rather complex. Skin dose monitoring in IORT is important due to the high dose prescription per treatment fraction.

Use of Polycaprolactone Electrospun Nanofibers as a Coating for Poly(methyl methacrylate) Bone Cement.

Poly(methyl methacrylate) (PMMA) bone cement has limited biocompatibility. Polycaprolactone (PCL) electrospun nanofiber (ENF) has many applications in the biomedical field due to its excellent biocompatibility and degradability. The effect of coating PCL ENF on the surface topography, biocompatibility, and mechanical strength of PMMA bone cement is not currently known.

Beam-Target Helicity Asymmetry for γ[over →]n[over →]→π^{-}p in the N^{*} Resonance Region.

We report the first beam-target double-polarization asymmetries in the γ+n(p)→π^{-}+p(p) reaction spanning the nucleon resonance region from invariant mass W=1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target.

Microgroove and Collagen-poly(ε-caprolactone) Nanofiber Mesh Coating Improves the Mechanical Stability and Osseointegration of Titanium Implants.

The effect of depositing a collagen (CG)-poly-ε-caprolactone (PCL) nanofiber mesh (NFM) at the microgrooves of titanium (Ti) on the mechanical stability and osseointegration of the implant with bone was investigated using a rabbit model. Three groups of Ti samples were produced: control Ti samples where there were no microgrooves or CG-PCL NFM, groove Ti samples where microgrooves were machined on the circumference of Ti, and groove-NFM Ti samples where CG-PCL NFM was deposited on the machined microgrooves. Each group of Ti samples was implanted in the rabbit femurs for eight weeks.

Environmental monitoring through use of silica-based TLD.

The sensitivity of a novel silica-based fibre-form thermoluminescence dosimeter was tested off-site of a rare-earths processing plant, investigating the potential for obtaining baseline measurements of naturally occurring radioactive materials. The dosimeter, a Ge-doped collapsed photonic crystal fibre (PCFc) co-doped with B, was calibrated against commercially available thermoluminescent dosimetry (TLD) (TLD-200 and TLD-100) using a bremsstrahlung (tube-based) x-ray source. Eight sampling sites within 1 to 20 km of the perimeter of the rare-earth facility were identified, the TLDs (silica- as well as TLD-200 and TLD-100) in each case being buried within the soil at fixed depth, allowing measurements to be obtained, in this case for protracted periods of exposure of between two to eight months.

Minimizing Stress Shielding and Cement Damage in Cemented Femoral Component of a Hip Prosthesis through Computational Design Optimization.

The average life expectancy of many people undergoing total hip replacement (THR) exceeds twenty-five years and the demand for implants that increase the load-bearing capability of the bone without affecting the short- or long-term stability of the prosthesis is high. Mechanical failure owing to cement damage and stress shielding of the bone are the main factors affecting the long-term survival of cemented hip prostheses and implant design must realistically adjust to balance between these two conflicting effects. In the following analysis we introduce a novel methodology to achieve this objective, the numerical technique combines automatic and realistic modeling of the implant and embedding medium, and finite element analysis to assess the levels of stress shielding and cement damage and, finally, global optimization, using orthogonal arrays and probabilistic restarts, were used.

Assessment of natural radioactivity and gamma-ray dose in monazite rich black Sand Beach of Penang Island, Malaysia.

Activity concentrations of primordial radionuclides in sand samples collected from the coastal beaches surrounding Penang Island have been measured using conventional γ-ray spectrometry, while in-situ γ-ray doses have been measured through use of a portable radiation survey meter. The mean activity concentrations for Ra, Th and K at different locations were found to be less than the world average values, while the Miami Bay values for Ra and Th were found to be greater, at 1023±47 and 2086±96Bqkg respectively. The main contributor to radionuclide enrichment in Miami Bay is the presence of monazite-rich black sands.

Heavy metals in human teeth dentine: A bio-indicator of metals exposure and environmental pollution.

With rapid urbanization and large-scale industrial activities, modern human populations are being increasingly subjected to chronic environmental heavy metal exposures. Elemental uptake in tooth dentine is a bioindicator, the uptake occurring during the formation and mineralization processes, stored to large extent over periods of many years. The uptake includes essential elements, most typically geogenic dietary sources, as well as non-essential elements arising through environmental insults.

Expression, crosslinking, and developing modulus master curves of recombinant resilin.

Resilin is a disordered elastomeric protein found in specialized regions of insect cuticles, where low stiffness and high resilience are required. Having a wide range of functions that vary among insect species, resilin operates across a wide frequency range, from 5Hz for locomotion to 13kHz for sound production. We synthesize and crosslink a recombinant resilin from clone-1 (exon-1+exon-2) of the gene, and determine the water content (approximately 80wt%) and dynamic mechanical properties, along with estimating surface energies relevant for adhesion.

Joint source and relay optimization for interference MIMO relay networks.

This paper considers multiple-input multiple-output (MIMO) relay communication in multi-cellular (interference) systems in which MIMO source-destination pairs communicate simultaneously. It is assumed that due to severe attenuation and/or shadowing effects, communication links can be established only with the aid of a relay node. The aim is to minimize the maximal mean-square-error (MSE) among all the receiving nodes under constrained source and relay transmit powers.

Plasma nitriding of titanium alloy: Effect of roughness, hardness, biocompatibility, and bonding with bone cement.

Titanium (Ti) alloys have been widely used in orthopedics and orthodontic surgeries as implants because of their beneficial chemical, mechanical, and biological properties. Improvement of these properties of a Ti alloy, Ti-6Al-4V Eli, is possible by the use of plasma nitriding treatment on the Ti alloy. The novelty of this study is the evaluation of a DC glow discharge nitrogen plasma treatment method on the surface, mechanical and biological properties of Ti alloy.

Cadmium-109 Radioisotope Adsorption onto Polypyrrole Coated Sawdust of Dryobalanops aromatic: Kinetics and Adsorption Isotherms Modelling.

A radiotracer study was conducted to investigate the removal characteristics of cadmium (109Cd) from aqueous solution by polypyrrole/ sawdust composite. Several factors such as solution pH, sorbent dosage, initial concentration, contact time, temperature and interfering metal ions were found to have influence on the adsorption process. The kinetics of adsorption was relatively fast, reaching equilibrium within 3 hours.

Quantification and Radiological Risk Estimation Due to the Presence of Natural Radionuclides in Maiganga Coal, Nigeria.

Following the increasing demand of coal for power generation, activity concentrations of primordial radionuclides were determined in Nigerian coal using the gamma spectrometric technique with the aim of evaluating the radiological implications of coal utilization and exploitation in the country. Mean activity concentrations of 226Ra, 232Th, and 40K were 8.18±0.