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This page shows you the 20 most read items in the past 30 days within this specialty in the MedWorm directory.

Injectable biodegradable hydrogels with tunable mechanical properties for the stimulation of neurogenesic differentiation of human mesenchymal stem cells in 3D culture.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report an injectable hydrogel scaffold system with tunable stiffness for controlling the proliferation rate and differentiation of human mesenchymal stem cells (hMSCs) in a three-dimensional (3D) context in normal growth media. The hydrogels composed of gelatin-hydroxyphenylpropionic acid (Gtn-HPA) conjugate were formed using the oxidative coupling of HPA moieties catalyzed by hydrogen peroxide (H(2)O(2)) and horseradish peroxidase (HRP). The stiffness of the hydrogels was readily tuned by varying the H(2)O(2) concentration without changing the concentration of polymer precursor. We found that the hydrogel stiffness str...
Source: Biomaterials - November 3, 2009 Category: Materials Science Authors: Wang LS, Chung JE, Pui-Yik Chan P, Kurisawa M Tags: Biomaterials Source Type: journals

Influence of curing protocol on selected properties of light-curing polymers: Degree of conversion, volume contraction, elastic modulus, and glass transition temperatureEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract: Objectives: The purpose of this study was to investigate the effect of light-curing protocol on degree of conversion (DC), volume contraction (C), elastic modulus (E), and glass transition temperature (Tg) as measured on a model polymer. It was a further aim to correlate the measured values with each other.Methods: Different light-curing protocols were used in order to investigate the influence of energy density (ED), power density (PD), and mode of cure on the properties. The modes of cure were continuous, pulse-delay, and stepped irradiation. DC was measured by Raman micro-spectroscopy. C was determined by pycn...
Source: Dental Materials - October 26, 2009 Category: Materials Science Authors: Magali Dewaele, Erik Asmussen, Anne Peutzfeldt, E. Christian Munksgaard, Ana R. Benetti, Gauthier Finné, Gaëtane Leloup, Jacques Devaux Source Type: journals

Structural–acoustic modal analysis of cylindrical shells: application to MRI scanner systemsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Conclusion These methods are effective for coupled and uncoupled modal analysis of MRI scanner systems and can be used for quiet MRI design or sound absorber design for existing MRI systems. Content Type Journal ArticleCategory Research ArticleDOI 10.1007/s10334-009-0185-zAuthors Gemin Li, Queen’s University Department of Mechanical Engineering McLaughlin Hall Kingston ON K7L 3N6 CanadaChris K. Mechefske, Queen’s University Department of Mechanical Engineering McLaughlin Hall Kingston ON K7L 3N6 Canada Journal Magnetic Resonance Materials in Physics, Biology and MedicineOnline ISSN 1352-8661...
Source: Magnetic Resonance Materials in Physics, Biology and Medicine - October 26, 2009 Category: Materials Science Tags: Magnetic Resonance Materials in Physics, Biology and Medicine Source Type: journals

The induction of tumor apoptosis in B16 melanoma following STAT3 siRNA delivery with a lipid-substituted polyethylenimine.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we investigated the potential of nanoparticles based on polyethylenimine (PEI) modified with stearic acid (StA), to deliver siRNA for efficient STAT3 downregulation in B16 melanoma cells. The B16 cells were targeted with approximately 6-200nm of siRNA complexes for 36h. Compared to the PEI complexes, the PEI-StA complexes showed higher potency in STAT3 silencing in B16 cells accompanied by a significant induction of IL-6 secretion and a reduction of VEGF production. Moreover, with PEI-StA complexes, the level of the cellular Caspase 3 activity (an indicator of apoptotic activity) was found to be 2.5 times hi...
Source: Biomaterials - November 12, 2009 Category: Materials Science Authors: Alshamsan A, Hamdy S, Samuel J, El-Kadi AO, Lavasanifar A, Uludağ H Tags: Biomaterials Source Type: journals

Nanocomposites for Engineering ApplicationsEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
(Source: Journal of Nanomaterials)
Source: Journal of Nanomaterials - August 24, 2009 Category: Materials Science Source Type: journals

Wear behavior of light-cured dental composites filled with porous glass-ceramic particles.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, novel bioactive glass-ceramic powders exhibiting different nominal calcium-mica to fluorapatite ratios were used as fillers for light-cured dental composites. Wear tests on the resulting samples were undertaken using a micro-tribometer with a linear reciprocating ball-on-flat geometry using lubrication from artificial saliva. The surfaces of the worn composites were then evaluated using optical microscopy. In order to enhance matrix bonding, the surfaces of the different particulates were treated using hydrofluoric acid to provide a porous surface and the resulting surface morphology was evaluated using scan...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Tan Y, Liu Y, Grover LM, Huang B Tags: J Mech Behav Biomed Mater Source Type: journals

Evaluation of Parenteral Depot Insulin Formulation using PLGA and PLA MicroparticlesEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PLGA and PLA microparticles entrapping insulin are prepared by solvent evaporation method and are evaluated in diabetes-induced rat for its efficacy in maintaining blood sugar level from a single intramuscular dose. In vitro release of insulin from PLGA and PLA microparticles are 75.35 ± 1.73% and 67.536 ± 2.23%, respectively in 168 h (7 days). Released insulin from polymer particles are mostly in monomeric form without aggregation. Optimal use of stabilizers during particle formulation helps in reducing protein denaturation and thus results in stabilized insulin-loaded polymer particles. Intramuscular admini...
Source: Journal of Biomaterials Applications - October 23, 2009 Category: Materials Science Authors: Naha, P. C., Kanchan, V., Panda, A. K. Tags: Articles Source Type: journals

A biomimetic hydrogel based on methacrylated dextran-graft-lysine and gelatin for 3D smooth muscle cell culture.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study reports synthesis of a methacrylate and lysine functionalized dextran and development of hydrogel composite systems based on this material and methacrylamide modified gelatin. The mechanical stiffness and degree of swelling of the hydrogels were varied by manipulation of the degree of functionalization of dextran and gelatin and concentration/composition of precursor solution. Human umbilical artery smooth muscle cells (SMCs) were encapsulated inside hydrogels during gel hardening with photopolymerization. Rapid cell spreading, extensive cellular network formation and high SMC proliferation occurred within softe...
Source: Biomaterials - November 6, 2009 Category: Materials Science Authors: Liu Y, Chan-Park MB Tags: Biomaterials Source Type: journals

Effect of fluorapatite additive on densification and mechanical properties of tricalcium phosphate.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Tricalcium phosphate and synthesized fluorapatite powder were mixed in order to elaborate biphasic composites. The samples were characterized by X-ray diffraction, differential thermal analysis, infrared spectroscopy, scanning electron microscopy and by an analysis using (31)P nuclear magnetic resonance. The sintering of tricalcium phosphate with different percentages of fluorapatite (13.26 wt%; 19.9 wt%; 33.16 wt% and 40 wt%) indicates the evolution of the microstructure, densification and mechanical properties. The Brazilian test was used to measure the rupture strength of the sintered biphasic composites. The mechan...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Bouslama N, Ben Ayed F, Bouaziz J Tags: J Mech Behav Biomed Mater Source Type: journals

Nanoparticles functionalised with recombinant single chain Fv antibody fragments (scFv) for the magnetic resonance imaging of cancer cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Superparamagnetic iron oxide nanoparticles (SPIONs) can substantially improve the sensitivity of magnetic resonance imaging (MRI). We propose that SPIONs could be used to target and image cancer cells if functionalised with recombinant single chain Fv antibody fragments (scFv). We tested our hypothesis by generating antibody-functionalised (abf) SPIONs using a scFv specific for carcinoembryonic antigen (CEA), an oncofoetal cell surface protein. SPIONs of different hydrodynamic diameter and surface chemistry were investigated and targeting was confirmed by ELISA, cellular iron uptake, confocal laser scanning microscopy ...
Source: Biomaterials - November 2, 2009 Category: Materials Science Authors: Vigor KL, Kyrtatos PG, Minogue S, Al-Jamal KT, Kogelberg H, Tolner B, Kostarelos K, Begent RH, Pankhurst QA, Lythgoe MF, Chester KA Tags: Biomaterials Source Type: journals

Movement of polymer microcarriers using a biomolecular motor.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This work enables polymer microcarriers to be transported on a motor protein coated substrate. The size of microencapsulation system- layered polymer capsules could be controlled through changing heating time during post-treatment. In this active biomimetic system, the microtubules act as shuttles that transport the attached polymer microcarriers. The velocity of the motility does not depend on size of the capsules but the fraction of mobile capsules depends on capsule size and biotinylation proportion of microtubule. The microtubule could also propel dextran-filled capsules to transport the internal components on the ...
Source: Biomaterials - October 29, 2009 Category: Materials Science Authors: Song W, Möhwald H, Li J Tags: Biomaterials Source Type: journals

An entropy spring model for the Young's modulus change of biodegradable polymers during biodegradation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This paper presents a model for the change in Young's modulus of biodegradable polymers due to hydrolysis cleavage of the polymer chains. The model is based on the entropy spring theory for amorphous polymers. It is assumed that isolated polymer chain cleavage and very short polymer chains do not affect the entropy change in a linear biodegradable polymer during its deformation. It is then possible to relate the Young's modulus to the average molecular weight in a computer simulated hydrolysis process of polymer chain sessions. The experimental data obtained by Tsuji [Tsuji, H., 2002. Autocatalytic hydrolysis of amorph...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Wang Y, Han X, Pan J, Sinka C Tags: J Mech Behav Biomed Mater Source Type: journals

Minimizing specimen length in elastic testing of end-constrained cancellous bone.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
End-constraint is needed when performing tensile and compressive testing of cancellous bone so that frictional and structural end-effects are minimized and the mechanical properties are not underestimated. Since many end-constrained testing techniques are limited to certain sites and species by the large specimen sizes required, reductions in overall specimen length would be advantageous. The following study examines the effect of specimen gauge length and aspect ratio on the elastic tensile testing of cancellous bone from the bovine femoral condyle. Three different nominal gauge lengths (10, 16, 22 mm) were examined a...
Source: Journal of the Mechanical Behavior of Biomedical Materials - November 3, 2009 Category: Materials Science Authors: Lievers WB, Waldman SD, Pilkey AK Tags: J Mech Behav Biomed Mater Source Type: journals

Engineering a scaffold-free 3D tumor model for in vitro drug penetration studies.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Three-dimensional (3D) in vitro cultures are recognized for recapitulating the physiological microenvironment and exhibiting high concordance with in vivo conditions. In cancer research, the multi-cellular tumor spheroid (MCTS) model is an established 3D cancer model that exhibits microenvironmental heterogeneity close to that of tumors in vivo. However, the established process of MCTS formation is time-consuming and often uncontrolled. Here, we report a method for engineering MCTS using a transient inter-cellular linker which facilitates cell-cell interaction. Using C3A cells (a hepatocellular carcinoma cell line) as ...
Source: Biomaterials - November 2, 2009 Category: Materials Science Authors: Ong SM, Zhao Z, Arooz T, Zhao D, Zhang S, Du T, Wasser M, van Noort D, Yu H Tags: Biomaterials Source Type: journals

Self-Assembly of phospholipid-analogous hyperbranched polymers nanomicelles for drug delivery.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A drug nanocarrier has been constructed through self-assembly of phospholipid analogous hyperbranched polymers (HPHEEP-alkyls) which contain a polar hyperbranched polyphosphate headgroup and many aliphatic tails. HPHEEP-alkyls were synthesized by self-condensing ring-opening polymerization of 2-(2-hydroxyethoxy)ethoxy-2-oxo-1,3,2-dioxaphospholane and then capped with palmitoyl chloride. Benefiting from the amphiphilic structure with the hydrophilic core and many hydrophobic tails, HPHEEP-alkyls were able to self-assemble into nanomicelles in aqueous media. Importantly, the size of the nanomicelles could be controlled c...
Source: Biomaterials - October 31, 2009 Category: Materials Science Authors: Liu J, Pang Y, Huang W, Zhu X, Zhou Y, Yan D Tags: Biomaterials Source Type: journals

Effect of resin-composite filler particle size and shape on shrinkage–strainEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract: Objectives: The aim of this study was to investigate the effect of variations in filler particle size and shape on the polymerization shrinkage–strain kinetics of resin-composites.Methods: A model series of 12 VLC resin-composites were studied. The particulate dispersed phase volume fraction was 56.7%: these filler particles were systematically graded in size, and further were either spherical or irregular. The bonded disk method was used to determine shrinkage–strain kinetics. Displacement was recorded following 40s irradiation (600mW/cm2) at 23°C (n=3). All data were captured for 60min and the final shrink...
Source: Dental Materials - October 26, 2009 Category: Materials Science Authors: Julian D. Satterthwaite, Karin Vogel, David C. Watts Source Type: journals

Biological responses to hydroxyapatite surfaces deposited via a co-incident microblasting technique.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study two methods for creating a HA layer on metal alloys that employ micro-blasting have been evaluated to determine if the inclusion of an abrasive agent can enhance the in vitro and in vivo performance of the modified surface. The first method employs direct micro-blasting using HA as the abrasive media, while the second employs a simultaneous blasting with an alumina abrasive and coincident blasting with HA as a dopant. Whereas, both methods were found to produce a surface which was enriched with HA, the respective microstructures created were significantly different. Detailed surface characterisation revealed ...
Source: Biomaterials - October 26, 2009 Category: Materials Science Authors: O'Hare P, Meenan BJ, Burke GA, Byrne G, Dowling D, Hunt JA Tags: Biomaterials Source Type: journals

Influence of contamination and cleaning on bond strength to modified zirconiaEmail this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Abstract: Objective: To evaluate the influence of contamination and cleaning procedures on shear bond strength (SBS) to modified zirconia surfaces.Methods: One hundred zirconium-oxide ceramic disks fabricated with a rough modified surface (Nobel Bond), which allows more micromechanical interlocking for adhesive cementation, were divided into five groups. Groups were contaminated with organic (OC; human blood and saliva) and/or inorganic contaminants (IC; type IV dental stone). For cleaning, modified surfaces were etched with phosphoric acid for 1min (PA) or fired in a ceramic furnace up to 910°C and cleaned in an ultrason...
Source: Dental Materials - October 26, 2009 Category: Materials Science Authors: Jin-Ho Phark, Sillas Duarte, Harold Kahn, Markus B. Blatz, Avishai Sadan Source Type: journals

Pharmacological activity and protein phosphorylation caused by nitric oxide-releasing microparticles.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Nitric oxide (NO)-releasing microparticles were developed as a potential treatment option against various blood flow irregulations including sexual dysfunction, atherosclerosis and metal stent-induced restenosis. Polymeric microparticles containing diethylenetriamine diazeniumdiolate (DETA NONOate), a NO donor, were prepared using modified double-emulsion solvent evaporation method to maximize the loading efficacy and stability of DETA NONOate. The pharmacological effects of the NO-releasing microparticles were evaluated by examining the changes in the vaginal blood flow in rats. The effects of NO on the phosphorylatio...
Source: Biomaterials - October 24, 2009 Category: Materials Science Authors: Yoo JW, Choe ES, Ahn SM, Lee CH Tags: Biomaterials Source Type: journals

Neuronal cell growth on iridium oxide.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study the biocompatibility of pure iridium and different iridium oxides that differ characteristically in their surface roughness was investigated using two different biological test systems, insect and vertebrate neurons. Iridium oxide surfaces were coated with Concanavalin A and poly-(d)-lysine. In detailed investigations (R(a) value determination, contact angle measurement, marker enzyme assay) the surface characteristics of non-modified and coated iridium oxide films were analysed, demonstrating that the materials can be successfully coated. Furthermore, we show that locust neurons grow well on all substrates t...
Source: Biomaterials - October 24, 2009 Category: Materials Science Authors: Göbbels K, Kuenzel T, van Ooyen A, Baumgartner W, Schnakenberg U, Bräunig P Tags: Biomaterials Source Type: journals