Collagen is the oldest and most abundant extracellular matrix protein that has found many applications in food, cosmetic, pharmaceutical, and biomedical industries First, an overview of the family of collagens and their respective structures, conformation, and biosynthesis is provided The advances and shortfalls of various collagen preparations (eg, mammalian/marine extracted collagen, cell-produced collagens, recombinant collagens, and collagen-like peptides) and crosslinking technologies (eg, chemical, physical, and biological) are then critically discussed Subsequently, an array of structural, thermal, mechanical, biochemical, and biological assays is examined, which are developed to analyze and characterize collagenous structures Lastly, a comprehensive review is provided on how advances in engineering, chemistry, and biology have enabled the development of bioactive, 3D structures (eg, tissue grafts, biomaterials, cell-assembled tissue equivalents) that closely imitate native supramolecular assemblies and have the capacity to deliver in a localized and sustained manner viable cell populations and/or bioactive/therapeutic molecules Clearly, collagens have a long history in both evolution and biotechnology and continue to offer both challenges and exciting opportunities in regenerative medicine as nature's biomaterial of choice

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The Collagen Suprafamily: From Biosynthesis to Advanced Biomaterial Development

Differential Thermal Analysis

Covering the full range of conditions, from rashes, to skin lesions and disorders of the hair, nail, and mucosa, Fitzpatrick's is a unique combination of text, clinical reference, and color atlas-one that gives you the best quality and most varied photographs of skin disorders available anywhere. The book features a consistent format featuring key facts pertaining to epidemiology, clinical manifestations, physical exam, diagnosis, and treatment, each paired with several clear photographs to show how the condition appears-plus boxed overviews of each disease category with severity-specific icons.

Fitzpatrick’s Color Atlas and Synopsis of Clinical Dermatology

Abstract The heat capacity of poly(lactic acid) (PLA) is reported from T=(5 to 600) K as obtained by differential scanning calorimetry (d.s.c.) and adiabatic calorimetry. The heat capacity of solid PLA is linked to its group vibrational spectrum and the skeletal vibrations, the latter being described by a Tarasov equation with Θ1=574 K, Θ2=Θ3=52 K, and nine skeletal vibrations. The calculated and experimental heat capacities agree to ±3% between T=(5 and 300) K. The experimental heat capacity of liquid PLA can be expressed by Cp(liquid)=(120.17+0.076T) J · K−1 · mol−1 and has been compared to the ATHAS Data Bank, using contributions of other polymers with the same constituent groups. The glass transition temperature of amorphous PLA occurs at T=332.5 K with a change in heat capacity of 43.8 J · K−1 · mol−1. Depending on thermal history, semi-crystalline PLA has a melting endotherm between T=(418 and 432) K with variable heats of fusion. For 100% crystalline PLA, the heat of fusion is estimated to be (6.55 ± 0.02) kJ · mol−1 at T=480 K. With these results, the enthalpy, entropy, and Gibbs function of crystalline and amorphous PLA were obtained. For semi-crystalline samples, one can check changes of crystallinity with temperature and judge the presence of rigid-amorphous fractions.

Heat Capacity of Poly(L-lactic acid)

Marine organisms are constituted by materials with a vast range of properties and characteristics that may justify their potential application within the biomedical field. Moreover, assuring the sustainable exploitation of natural marine resources, the valorisation of residues from marine origin, like those obtained from food processing, constitutes a highly interesting platform for development of novel biomaterials, with both economic and environmental benefits. In this perspective, an increasing number of different types of compounds are being isolated from aquatic organisms and transformed into profitable products for health applications, including controlled drug delivery and tissue engineering devices. This report reviews the work that is being developed on the isolation and characterisation of some polysaccharides, proteins, glycosaminoglycans and ceramics from marine raw materials. Emphasis is given to agar, alginates, carrageenans, chitin and chitosan, among other polysaccharides, collagen, glycosaminoglycans such as chondroitin sulphate, heparin and hyaluronic acid, calcium phosphorous compounds and biosilica. Finally, this report ends by reviewing the application of the previously mentioned materials on specific biomedical applications, in particular their participation on the development of controlled drug delivery systems and tissue engineering scaffolds.

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Materials of marine origin: a review on polymers and ceramics of biomedical interest

Amino acid composition in determination of collagen origin and assessment of physical factors effects

Quantitative analysis of blood viscosity was performed on the basis of mathematical models of non-Newtonian fluid shear flow behavior (Casson, Ree-Eyring and Quemada). A total of 100 blood samples were drawn from clinically stable survivors of myocardial infarction, treated with aspirin or acenocoumarol and controls to these drugs. Whole blood and plasma viscosity were measured at a broad range of shear rates using a rotary-oscillating viscometer Contraves LS40. Numerical analysis of the experimental data was carried out by means of linear (for Casson) and non-linear regression for the remaining models. In the evaluation of the results, both the fit quality and physical interpretation of the models’ parameters were considered. The Quemada model fitted most precisely with the experimental findings and, despite the controversies concerning the relationship between in vivo tissue perfusion and in vitro rheological measurements, seemed to be a valuable method enhancing investigation possibilities of cardiovascular patients. Our results suggest that aspirin does not affect blood rheological properties, while acenocoumarol may slightly alter red cell deformability and rouleaux formation.

Comparison of three rheological models of shear flow behavior studied on blood samples from post-infarction patients

Comparison of thermal properties of fish collagen and bovine collagen in the temperature range 298-670K.

Introduction and objective: Sunlight is the major source of the energy on Earth. Visible light, ultraviolet and infrared radiation are necessary to sustain life on our planet. However, besides the range of positive eects, such as photosynthesis in plants, warmth, vision, and synthesis of vitamin D, sunlight may also be responsible for negative biologic eects - sunburn, induction of photodermatoses or carcinogenesis. Ultraviolet is regarded as the major environmental, physical hazard to the human skin. Abbreviated description of the state of knowledge: The acute clinical eect of ultraviolet involves melanogenesis, i.e. tanning, which protects from sunburn if exposure is overdosed. A single exposure, as well as acute suberythemal irradiation, suppresses sensitization of the contact hypersensitivity. The chronic biological eects are photoageing and skin cancer, especially squamous cell carcinoma (SCC). Vitamin D synthesis is regarded as a benet of natural acute and chronic exposure to ultraviolet. Ultraviolet also plays an important role in aetiology of the group of disorders characterized by photosensitivity. On the other hand ultraviolet is a known inducer of immunosuppression in the skin; therefore, phototherapy is a therapeutic option for patients with activation of dermal immunity. Summary: Without sunlight, the existence of life on Earth is not possible. On the other hand, UVR radiation is regarded as representing one of the most important environmental hazards for human skin. For a better understanding of the mechanisms related to the inuence of UVR on human skin, and the most dangerous chronic eects of carcinogenesis, it is necessary to undertake some protective activities. Moreover, UVR may become our ally in the treatment of selected skin disorders.

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The sun - our friend or foe?

Temperature induced structural transformation of bone collagen has been studied by electric conductivity measurements and differential scanning calorimetry The process of collagen denaturation and structural transformation was manifested as an endothermic peak on the thermogram and as an increase in the electric conductivity, within the range of 400–455 K The temperatures of denaturation assessed by both methods were 429 K and 436 K respectively The experiments were carried out on dry bovine bone heated in the temperature range of 295–520 K In order to remove free water absorbed by bone samples, they were pre-heated at 380 K prior to the measurements

Leszek Kubisz

Papers

Amino acid composition in determination of collagen origin and assessment of physical factors effects

Comparison of three rheological models of shear flow behavior studied on blood samples from post-infarction patients

Comparison of thermal properties of fish collagen and bovine collagen in the temperature range 298-670K.

The sun - our friend or foe?

Differential scanning calorimetry and temperature dependence of electric conductivity in studies on denaturation process of bone collagen