keratin biomaterials kerateines: Topics by WorldWideScience.org

The elaborate structure of spider silk

No abstract prepared.

2006-07-01

Stereocomplexed PLA-PEG Nanoparticles with Dual-Emissive Boron Dyes for Tumor Accumulation

Biomaterials, having evolved over millions of years, often exceed man-made materials in their properties. Spider silk is one outstanding fibrous biomaterial which consists almost entirely of large proteins....Full Text Available

2008-10-01

The utility of naphthyl-keratin adducts as biomarkers for jet-fuel exposure.

Responsive biomaterials play important roles in imaging, diagnostics, and therapeutics. Polymeric nanoparticles (NPs) containing hydrophobic and hydrophilic segments are one class of biomaterial...Full Text Available

2010-09-28

Osseointegration of zirconia implants compared with titanium: an in vivo study

We investigated the association between biomarkers of dermal exposure, naphthyl-keratin adducts (NKA), and urine naphthalene biomarker levels in 105 workers routinely exposed to jet-fuel. A moderate correlation was observed between NKA and urine naphthalene levels (p?=?0.061). The NKA, post-exposure breath naphthalene, and male gender were associated with an increase, while CYP2E1*6 DD and GSTT1-plus (++/+-) genotypes were associated with a decrease in urine naphthalene level (p?

2011-09-30

FATIGUE OF BIOMATERIALS: HARD TISSUES

BackgroundTitanium and titanium alloys are widely used for fabrication of dental implants. Since the material composition and the surface topography of a biomaterial play a fundamental...Full Text Available

The inhibition of staphylococcus epidermidis biofilm formation by vancomycin-modified titanium alloy and implications for the treatment of periprosthetic infection

The fatigue and fracture behavior of hard tissues are topics of considerable interest today. This special group of organic materials comprises the highly mineralized and load-bearing tissues...Full Text Available

2010-09-01

Calcification of subcutaneously implanted type I collagen sponges. Effects of formaldehyde and glutaraldehyde pretreatments.

Peri-prosthetic infections are notoriously difficult to treat as the biomaterial implant is ideal for bacterial adhesion and biofilm formation, resulting in decreased antibiotic sensitivity....Full Text Available

2008-12-01

Time-resolved confocal fluorescence spectroscopy reveals the structure and metabolic state of epithelial tissue

Although collagen-containing implants are widely used in various surgical applications, there has been relatively little attention paid to the possibility that this type of biomaterial may undergo pathologic...Full Text Available

1986-01-01

The models of experimental magnetic measurements of various biological samples

Autofluorescence spectroscopy has been a widely explored technique for in vivo and noninvasive diagnosis of pre-cancer lesions in epithelium where 90% cancers originate. For extracting more accurate fluorescence information for cancer diagnosis, depth-resolved fluorescence measurements are crucial to assess NADH and FAD in non-keratinized epithelial layer and collagen in stromal layer, respectively. In this study, we achieved the depth-resolved fluorescence spectral measurements of squamous epithelial tissue based on confocal technique. We found that in non-keratinized epithelial layer the fluorescence signals excited at 405 nm were the combination of NADH and FAD fluorescence and could be used for evaluating the redox ratio. Moreover, we found that confocal time-resolved autofluorescence measurements of epithelial tissue with 405 nm excitations could provide the information on the layered tissue structure. All depth-resolved autofluorescence ...

2007-03-01

International Nuclear Information System (INIS)

Complete text of publication follows. At the Geomagnetic Institute, in the Laboratory for paleomagnetism and archeomagnetism research and at the Geomagnetic Observatory, Grocka (GCK) during the period from November 2004 to February 2008 the researchers carried out experimental magnetic measurements of the total-intensity gradient of the magnetic field vector (changes in the total magnetisation vector) of various biomaterials. Measurements of the gradient total intensity of the magnetic field vector were carried out by GSM-19 magnetometers of high accuracy and recording resolution (accuracy: #DELTA#F=0.1 nT; sampling rate: 1-5 per second). During these experimental biomagnetic measurements samples of water, tissue, blood, cotton, wool, pitch and magnetite-powder were used. In this study, the part of the biomagnetic measurement results relate to the water, blood and tissue. The results of the measurements of gradient total-intensity of the magnetic field for the ...

2009-08-23

Medical and pharmaceutical applications of polymers: A review paper

International Nuclear Information System (INIS)

This review begins with an historical account of biomaterials applications followed by a concise description of the phenomena taking place between the living tissues and non-living materials containing them. After describing the requirements for biodegradability and the mechanisms involved, a thorough literature survey of such polymers is presented. In the end a very short review of the work done in this area by the authors in recent years is given, including: the synthesis of a wide variety of biodegradable di-and tri-block copolymers, preparation of microparticles; stealth-and immuno-liposomes; dendrosomes and polymersomes; and some of their applications in drug and gene delivery.

The use of combinatorial topographical libraries for the screening of enhanced osteogenic expression and mineralization

British Library Electronic Table of Contents (United Kingdom)

Nano- and microstructured surfaces are known to impact on the binding and differentiation of cells, but the detailed basic understanding of the underlying regulatory mechanisms is still scarce, which impedes the rational design of smart biomaterials. Towards a comprehensive analysis of the interplay between topographical parameters such as feature design and lateral and vertical dimensions we here report on a combinatorial screening approach, BioSurface Structure Array (BSSA) of test squares each with a distinct topography. Using such BSSA libraries of 504 topographically distinct surface structures, we have identified combinations of size, gap and height of structures which enhance mineralization as well as the expression of osteogenic markers of a preosteoblastic murine cell line. This g...

2009-01-01

The preparation of polyurethane foam combined with pH-sensitive alginate/bentonite hydrogel for wound dressings

British Library Electronic Table of Contents (United Kingdom)

Polyurethane (PU) foam was combined with protein drug-loaded pH-sensitive alginate-bentonite hydrogel for wound dressings. Alginate is a linear copolymer composed of 1?4-linked ?-D-mannuronic acid (M) and its c-5-epimer ?-Lguluronic acid (G). The amount of (M) and (G) and their sequential distribution are varied depending on the alginate source. Soluble sodium alginate can become a hydrogel when cross-linked with divalent cations and has widespread applications in the food, drink, pharmaceutical and bioengineering industries. Recently, it has been also proposed as a biomaterial for drug delivery systems. Bentonites are the natural inorganic polymers consisting of a large proportion of expandable clay minerals with a three-layer structure such as montmorillonite, beidellite, nontronite, etc...

2011-01-01

Proteomic analysis of sericin in Bombyx mori cocoons

British Library Electronic Table of Contents (United Kingdom)

Cocoon sericin plays an important role in the reeling of silk and serves as a valuable biomaterial in the field of biomedicine, skincare, and food industries; however, knowledge about cocoon sericin proteins has been limited. For a comprehensive study on sericin, cocoons of eight varieties of silkworm of different geographic origin and with varied cocoon color were analyzed utilizing proteomics and bioinformatics approaches. The electrophoresis pattern demonstrated some common protein bands for all silkworm varieties and distinctive protein bands for some of those examined in the present study. The Ser2 protein, a new Ser3 protein, and four other novel sericin proteins were identified in cocoons for the first time. Products of both Ser1 and Ser3 genes appear to be ubiquitous in the cocoon ...

2011-01-01

Biosorption of lead by citrobacter freundii immobilized on hazelnut shells

Multiscale modeling of transdermal drug delivery

Biosorption of lead from aqueous solutions by living and immobilized cell of C. freundii was examined as a function of metal concentration in a batch laboratory bioreactor. Lead concentrations were analyzed using Atomic Absorption Spectrophotometer (AAS). X-ray Energy Dispersion (EDX) analyses were made in order to determine the accumulation of lead on the cells and shell surfaces. Before and after the experiments the biomaterials and adsorbents were examined by Scanning Electron Microscopy (SEM). Biosorption was detected over a range of initial lead concentrations from 25{times}10{sup -3} to 200{times}10{sup -3} kg/m{sup 3}. 15 refs., 4 figs.

1996-12-31

Fiscal 1993 report on results of R and D on innovative technology for producing advanced biomaterial. Peptide applied carbon dioxide fixation/effective utilization technology (First volume); 1993 nendo senshin bio zairyo no sosei kako gijutsu no kenkyu kaihatsu seika hokokusho. 1. Peptide oyo nisanka tanso koteika yuko riyo gijutsu

This study addresses the modeling of transdermal diffusion of drugs, to better understand the permeation of molecules through the skin, and especially the stratum corneum, which forms the main permeation barrier of the skin. In transdermal delivery of systemic drugs, the drugs diffuse from a patch placed on the skin through the epidermis to the underlying blood vessels. The epidermis is the outermost layer of the skin and can be further divided into the stratum corneum (SC) and the viable epidermis layers. The SC consists of keratinous cells (corneocytes) embedded in the lipid multi-bilayers of the intercellular space. It is widely accepted that the barrier properties of the skin mostly arises from the ordered structure of the lipid bilayers. The diffusion path, at least for lipophilic molecules, seems to be mainly through the lipid bilayers. Despite the advantages of transdermal drug delivery compared to other drug delivery routes such as oral dosing and ...

2006-01-01

Biphasic calcium sulfate dihydrate/iron-modified alpha-tricalcium phosphate bone cement for spinal applications: in vitro study

Technology is being developed for preparing functional materials by synthesizing new functional peptides in which non-natural amino acid needed for the functional manifestation is introduced, and by modifying the surface of a base plate such as silica glass by using such peptides. Activities were conducted in the three areas of (1) creation of functional molecules, (2) materialization technology, and (3) comprehensive investigation and research; the activities were carried out independently and parallelly in the first two areas. In (1), design technique for the structures and functions of peptides was developed, as were conformational control technique, synthesis of peptides having optical/electronic functions, peptide synthesis by an enzyme method, and R and D on introduction of non-natural amino acid into peptides; in (2), element technologies were developed such as substrate forming technique (pattern forming and thin film forming technology), substrate modification technique, ...

1994-03-01

Development and cytotoxicity evaluation of SiAlONs ceramics

In this study, the cytocompatibility of new 'iron-modified/alpha-tricalcium phosphate (IM/alpha-TCP) and calcium sulfate dihydrate (CSD)' bone cement (IM/alpha-TCP/CSD-BC) intended for spinal applications has been approached. The objective was to investigate by direct-contact osteoblast-like cell cultures (from 1 to 14 days) the in vitro cell adhesion, proliferation, morphology and cytoskeleton organization of MG-63 cells seeded onto the new cements. The results were as follows: (a) quantitative MTT-assay and scanning electron microscopy (SEM) showed that cell adhesion, proliferation and viability were not affected with time by the presence of iron in the cements; (b) double immunofluorescent labeling of F-actin and alpha-tubulin showed a dynamic interaction between the cell and its porous substrates sustaining the locomotion phenomenon on the cements' surface, which favored the colonization, and confirming the biocompatibility of the experimental cements; ...

2010-04-15

International Nuclear Information System (INIS)

SiAlONs are ceramics with high potential as biomaterials due to their chemical stability, associated with suitable mechanical properties, such as high fracture toughness and fracture resistance. The objective of this work was to investigate the mechanical properties and the cytotoxicity of these ceramic materials. Three different compositions were prepared, using silicon nitride, aluminum nitride and a rare earth oxide mixture as starting powders, yielding Si_3N_4-SiAlON composites or pure SiAlON ceramics, after hot-pressing at 1750 deg. C, for 30 min. The sintered samples were characterized by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). Furthermore, hardness and fracture toughness were determined using the Vicker's indentation method. The biological compatibility was evaluated by in vitro cytotoxicity tests. Ceramic with elevated hardness, ranging between 17 and 21 GPa, and high fracture toughness of 5 to 6 MPa m"1"/"2 were obtained. ...

2007-01-01

A biomass-supported Na2CO3 sorbent for flue gas desulfurization.

Multi-functional biomass systems

A novel sorbent for SO2 removal has been investigated. The sorbent is obtained by conventional incipient wetness impregnation of abandoned biomaterials (straw or dried leaves) with an aqueous solution of Na2CO3. A material with the composition 80 wt % Na2CO3/straw shows a desulfurization activity which is both higher and faster than that of the reference sample Na2CO3/gamma-Al2O3. The breakthrough and stoichiometric SO2 adsorption efficiencies for 80 wt % Na2CO3/straw reach 48.9% and 80.6%, respectively, at a temperature of 80 degrees C. The adsorption efficiencies are almost constant in the temperature range 70 to 300 degrees C. According to IR and XPS analysis the main products observed on the spent sorbent are sulfite below 150 degrees C and sulfate at 300 degrees C. The Na2CO3 in 80 wt % Na2CO3/straw can potentially be recycled by the oxidation of the straw with concomitant reduction of the sulfite species to elemental sulfur, making the proposed process CO2 ...

2003-06-01

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Plasma-based ion implantation and deposition: A review of physics,technology, and applications

The central research question of this thesis is: What is the potential of multi-functional biomass systems to improve the costs and the land use efficiency of saving non-renewable energy consumption and reducing GHG (greenhouse gases) emissions in quantitative terms? Therefore, in the following chapters the performance of multi-functional biomass systems is quantified. Biomass system costs are investigated from a societal perspective using e.g. low discount rates. A main focus will be on the review of methodologies for accounting GHG emissions, non-renewable energy consumption, agricultural land use and costs as well as the adaptation of these methodologies to special aspects of multifunctional biomass use. The analysis of the potential benefits of multi-functional biomass systems is carried out by several case studies of biomass systems including various waste treatment technologies for the short term that appeared promising after a first review. Because at present the shift of ...

2004-12-01

Formation of silk fibroin nanoparticles in water-miscible organic solvent and their characterization

After pioneering work in the 1980s, plasma-based ion implantation (PBII) and plasma-based ion implantation and deposition (PBIID) can now be considered mature technologies for surface modification and thin film deposition. This review starts by looking at the historical development and recalling the basic ideas of PBII. Advantages and disadvantages are compared to conventional ion beam implantation and physical vapor deposition for PBII and PBIID, respectively, followed by a summary of the physics of sheath dynamics, plasma and pulse specifications, plasma diagnostics, and process modeling. The review moves on to technology considerations for plasma sources and process reactors. PBII surface modification and PBIID coatings are applied in a wide range of situations. They include the by-now traditional tribological applications of reducing wear and corrosion through the formation of hard, tough, smooth, low-friction and chemically inert phases and coatings, e.g. for engine components. ...

2005-05-16

Boundary Migration in Rutile

When Silk fibre derived from Bombyx mori, a native biopolymer, was dissolved in highly concentrated neutral salts such as CaCl{sub 2}, the regenerated liquid silk, a gradually degraded peptide mixture of silk fibroin, could be obtained. The silk fibroin nanoparticles were prepared rapidly from the liquid silk by using water-miscible protonic and polar aprotonic organic solvents. The nanoparticles are insoluble but well dispersed and stable in aqueous solution and are globular particles with a range of 35-125 nm in diameter by means of TEM, SEM, AFM and laser sizer. Over one half of the {epsilon}-amino groups exist around the protein nanoparticles by using a trinitrobenzenesulfonic acid (TNBS) method. Raman spectra shows the tyrosine residues on the surface of the globules are more exposed than those on native silk fibers. The crystalline polymorph and conformation transition of the silk nanoparticles from random-coil and {alpha}-helix form (Silk I) into anti-parallel {beta}-sheet form ...

2007-10-15