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Search Results: 1 - 10 of 4238 matches for " Bruce Milthorpe "
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A Therapeutic Potential for Marine Skeletal Proteins in Bone Regeneration
David W. Green,Matthew P. Padula,Jerran Santos,Joshua Chou,Bruce Milthorpe,Besim Ben-Nissan
Marine Drugs , 2013, DOI: 10.3390/md11041203
Abstract: A vital ingredient for engineering bone tissue, in the culture dish, is the use of recombinant matrix and growth proteins to help accelerate the growth of cultivated tissues into clinically acceptable quantities. The skeletal organic matrices of calcifying marine invertebrates are an untouched potential source of such growth inducing proteins. They have the advantage of being ready-made and retain the native state of the original protein. Striking evidence shows that skeleton building bone morphogenic protein-2/4 (BMP) and transforming growth factor beta (TGF-β) exist within various marine invertebrates such as, corals. Best practice mariculture and the latest innovations in long-term marine invertebrate cell cultivation can be implemented to ensure that these proteins are produced sustainably and supplied continuously. This also guarantees that coral reef habitats are not damaged during the collection of specimens. Potential proteins for bone repair, either extracted from the skeleton or derived from cultivated tissues, can be identified, evaluated and retrieved using chromatography, cell assays and proteomic methods. Due to the current evidence for bone matrix protein analogues in marine invertebrates, together with the methods established for their production and retrieval there is a genuine prospect that they can be used to regenerate living bone for potential clinical use.
The Therapeutic Effect on Bone Mineral Formation from Biomimetic Zinc Containing Tricalcium Phosphate (ZnTCP) in Zinc-Deficient Osteoporotic Mice
Joshua Chou, Jia Hao, Hirokazu Hatoyama, Besim Ben-Nissan, Bruce Milthorpe, Makoto Otsuka
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0071821
Abstract: The aim of this study was to evaluate the therapeutic efficacy of biomimetic zinc-containing tricalcium phosphate (ZnTCP) produced by hydrothermally converting calcium carbonate exoskeletons from foraminifera, in the treatment of osteoporotic mice. X-Ray powder diffraction showed crystallographic structures matching JCPDS profile for tricalcium phosphate. Mass spectroscopy used to calculate total composition amount showed similar amount of calcium (5×104 μg/g) and phosphate (4×104 ppm) after conversion and the presence of zinc (5.18×103 μg/g). In vitro zinc release showed no release in PBS buffer and <1% zinc release in 7 days. In vivo evaluation was done in ovariectomized mice by implanting the ZnTCP samples in the soft tissues near the right femur bone for four weeks. Thirty ddY mice (5 weeks old, average weight of 21 g) were divided into six experimental groups (normal, sham, OVX, β-TCP, ZnTCP and direct injection of zinc). CT images were taken every two weeks where the bone mineral density (BMD) and bone mineral content (BMC) were calculated by software based on CT images. The ZnTCP group exhibits cortical and cancellous bone growth of 45% and 20% respectively. While sham, OVX and β-TCP suffered from bone loss. A correlation was made between the significant body weight increase in ZnTCP with the significant increase in plasma zinc level compared with OVX. The presented results indicate that biomimetic ZnTCP were effective in preventing and treating bone loss in osteoporotic mice model.
Controlled Release of Simvastatin from Biomimetic β-TCP Drug Delivery System
Joshua Chou, Tomoko Ito, David Bishop, Makoto Otsuka, Besim Ben-Nissan, Bruce Milthorpe
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0054676
Abstract: Simvastatin have been shown to induce bone formation and there is currently a urgent need to develop an appropriate delivery system to sustain the release of the drug to increase therapeutic efficacy whilst reducing side effects. In this study, a novel drug delivery system for simvastatin by means of hydrothermally converting marine exoskeletons to biocompatible beta-tricalcium phosphate was investigated. Furthermore, the release of simvastatin was controlled by the addition of an outer apatite coating layer. The samples were characterized by x-ray diffraction analysis, fourier transform infrared spectroscopy, scanning electron microscopy and mass spectroscopy confirming the conversion process. The in-vitro dissolution of key chemical compositional elements and the release of simvastatin were measured in simulated body fluid solution showing controlled release with reduction of approximately 25% compared with un-coated samples. This study shows the potential applications of marine structures as a drug delivery system for simvastatin.
Bone Regeneration of Rat Tibial Defect by Zinc-Tricalcium Phosphate (Zn-TCP) Synthesized from Porous Foraminifera Carbonate Macrospheres
Joshua Chou,Jia Hao,Shinji Kuroda,David Bishop,Besim Ben-Nissan,Bruce Milthorpe,Makoto Otsuka
Marine Drugs , 2013, DOI: 10.3390/md11125148
Abstract: Foraminifera carbonate exoskeleton was hydrothermally converted to biocompatible and biodegradable zinc-tricalcium phosphate (Zn-TCP) as an alternative biomimetic material for bone fracture repair. Zn-TCP samples implanted in a rat tibial defect model for eight weeks were compared with unfilled defect and beta-tricalcium phosphate showing accelerated bone regeneration compared with the control groups, with statistically significant bone mineral density and bone mineral content growth. CT images of the defect showed restoration of cancellous bone in Zn-TCP and only minimal growth in control group. Histological slices reveal bone in-growth within the pores and porous chamber of the material detailing good bone-material integration with the presence of blood vessels. These results exhibit the future potential of biomimetic Zn-TCP as bone grafts for bone fracture repair.
Marine Structure Derived Calcium Phosphate–Polymer Biocomposites for Local Antibiotic Delivery
Innocent J. Macha,Sophie Cazalbou,Besim Ben-Nissan,Kate L. Harvey,Bruce Milthorpe
Marine Drugs , 2015, DOI: 10.3390/md13010666
Abstract: Hydrothermally converted coralline hydroxyapatite (HAp) particles loaded with medically active substances were used to develop polylactic acid (PLA) thin film composites for slow drug delivery systems. The effects of HAp particles within PLA matrix on the gentamicin (GM) release and release kinetics were studied. The gentamicin release kinetics seemed to follow Power law Korsmeyer Peppas model with mainly diffusional process with a number of different drug transport mechanisms. Statistical analysis shows very significant difference on the release of gentamicin between GM containing PLA (PLAGM) and GM containing HAp microspheres within PLA matrix (PLAHApGM) devices, which PLAHApGM displays lower release rates. The use of HAp particles improved drug stabilization and higher drug encapsulation efficiency of the carrier. HAp is also the source of Ca 2+ for the regeneration and repair of diseased bone tissue. The release profiles, exhibited a steady state release rate with significant antimicrobial activity against Staphylococcus aureus ( S. aureus) (SH1000) even at high concentration of bacteria. The devices also indicated significant ability to control the growth of bacterial even after four weeks of drug release. Clinical release profiles can be easily tuned from drug-HAp physicochemical interactions and degradation kinetics of polymer matrix. The developed systems could be applied to prevent microbial adhesion to medical implant surfaces and to treat infections mainly caused by S. aureus in surgery.
Associated Legendre Polynomials and Spherical Harmonics Computation for Chemistry Applications
Taweetham Limpanuparb,Josh Milthorpe
Physics , 2014,
Abstract: Associated Legendre polynomials and spherical harmonics are central to calculations in many fields of science and mathematics - not only chemistry but computer graphics, magnetic, seismology and geodesy. There are a number of algorithms for these functions published since 1960 but none of them satisfy our requirements. In this paper, we present a comprehensive review of algorithms in the literature and, based on them, propose an efficient and accurate code for quantum chemistry. Our requirements are to efficiently calculate these functions for all non-negative integer degrees and orders up to a given number (<=1000) and the absolute or the relative error of each calculated value should not exceed 10E-10. We achieve this by normalizing the polynomials, employing efficient and stable recurrence relations, and precomputing coefficients. The algorithm presented here is straightforward and may be used in other areas of science.
Model Accuracy and Runtime Tradeoff in Distributed Deep Learning
Suyog Gupta,Wei Zhang,Josh Milthorpe
Computer Science , 2015,
Abstract: This paper presents Rudra, a parameter server based distributed computing framework tuned for training large-scale deep neural networks. Using variants of the asynchronous stochastic gradient descent algorithm we study the impact of synchronization protocol, stale gradient updates, minibatch size, learning rates, and number of learners on runtime performance and model accuracy. We introduce a new learning rate modulation strategy to counter the effect of stale gradients and propose a new synchronization protocol that can effectively bound the staleness in gradients, improve runtime performance and achieve good model accuracy. Our empirical investigation reveals a principled approach for distributed training of neural networks: the mini-batch size per learner should be reduced as more learners are added to the system to preserve the model accuracy. We validate this approach using commonly-used image classification benchmarks: CIFAR10 and ImageNet.
Engineering thick tissues - the vascularisation problem
H C H Ko,B K Milthorpe,C D McFarland
European Cells and Materials (ECM) , 2007,
Abstract: The ability to create thick tissues is a major tissue engineering challenge, requiring the development of a suitable vascular supply. Current trends are seeing the utilization of cells seeded into hybrid matrix/scaffold systems to create in vitro vascular analogues. Approaches that aim to create vasculature in vitro include the use of biological extracellular matrices such as collagen hydrogels, porous biodegradable polymeric scaffolds with macro- and micro-lumens and micro-channels, co-culture of cells, incorporation of growth factors, culture in dynamic bioreactor environments, and combinations of these. Of particular interest are those approaches that aim to create bioengineered tissues in vitro that can be readily connected to the host's vasculature following implantation in order to maintain cell viability.
A Bioinformatics-Inspired Adaptation to Ukkonen’s Edit Distance Calculating Algorithm and Its Applicability Towards Distributed Data Mining  [PDF]
Johnson Bruce
Journal of Software Engineering and Applications (JSEA) , 2008, DOI: 10.4236/jsea.2008.11002
Abstract: Edit distance measures the similarity between two strings (as the minimum number of change, insert or delete operations that transform one string to the other). An edit sequence s is a sequence of such operations and can be used to represent the string resulting from applying s to a reference string. We present a modification to Ukkonen’s edit distance calculating algorithm based upon representing strings by edit sequences. We conclude with a demonstration of how using this representation can improve mitochondrial DNA query throughput performance in a distributed computing environment.
A Field Exploration of Informal Workplace Communication  [PDF]
Bruce Fortado
Sociology Mind (SM) , 2011, DOI: 10.4236/sm.2011.14027
Abstract: Two views of informal communication are developed for purposes of comparison. Multiple incidents from two US companies are described based on fieldwork. In both cases, managerial efforts were made to quell gossip. Paradoxically, the versions multiplied at the first site and a gossip spiral occurred at the second. Our inductive analysis reveals the shortcomings of the existing “best practices” and simple theories. Notably, in both cases certain aspects of informal employee organization were more functional than some of the formal practices were. Due to the complex nature of these social situations, great care must be taken in evaluating them and charting a course.
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