In vitro evidences of different fibroblast morpho-functional responses to red, near-infrared and violet-blue photobiomodulation: Clues for addressingwound healing

Although photobiomodulation (PBM) has proven promising to treat wounds, the lack of univocal guidelines and of a thorough understanding of light–tissue interactions hampers its mainstream adoption for wound healing promotion. This study compared murine and human fibroblast responses to PBM by red (635 ± 5 nm), near-infrared (NIR, 808 ± 1 nm), and violet-blue (405 ± 5 nm) light (0.4 J/cm2 energy density, 13 mW/cm2 power density). Cell viability was not altered by PBM treatments. Light and confocal laser scanning microscopy and biochemical analyses showed, in red PBM irradiated cells: F-actin assembly reduction, up-regulated expression of Ki67 proliferation marker and of vinculin in focal adhesions, type-1 collagen down-regulation, matrix metalloproteinase-2 and metalloproteinase-9 expression/functionality increase concomitant to their inhibitors (TIMP-1 and TIMP-2) decrease. Violet-blue and even more NIR PBM stimulated collagen expression/deposition and, likely, cell differentiation towards (proto)myofibroblast phenotype. Indeed, these cells exhibited a higher polygonal surface area, stress fiber-like structures, increased vinculin- and phospho-focal adhesion kinase-rich clusters and α-smooth muscle actin. This study may provide the experimental groundwork to support red, NIR, and violet-blue PBM as potential options to promote proliferative and matrix remodeling/maturation phases of wound healing, targeting fibroblasts, and to suggest the use of combined PBM treatments in the wound management setting

Film cooling adiabatic effectiveness measurements of pressure side trailing edge cooling configurations

Nowadays total inlet temperature of gas turbine is far above the permissible metal temperature; as a consequence, advanced cooling techniques must be applied to protect from thermal stresses, oxidation and corrosion the components located in the high pressure stages, such as the blade trailing edge. A suitable design of the cooling system for the trailing edge has to cope with geometric constraints and aerodynamic demands; state-of-the-art of cooling concepts often use film cooling on blade pressure side: the air taken from last compressor stages is ejected through discrete holes or slots to provide a cold layer between hot mainstream and the blade surface. With the goal of ensuring a satisfactory lifetime of blades, the design of efficient trailing edge film cooling schemes and, moreover, the possibility to check carefully their behavior, are hence necessary to guarantee an appropriate metal temperature distribution. For this purpose an experimental survey was carried out to investigate the film covering performance of different pressure side trailing edge cooling systems for turbine blades. The experimental test section consists of a scaled-up trailing edge model installed in an open loop suction type test rig. Measurements of adiabatic effectiveness distributions were carried out on three trailing edge cooling system configurations. The baseline geometry is composed by inclined slots separated by elongated pedestals; the second geometry shares the same cutback configuration, with an additional row of circular film cooling holes located upstream; the third model is equipped with three rows of in-line film cooling holes. Experiments have been performed at nearly ambient conditions imposing several blowing ratio values and using carbon dioxide as coolant in order to reproduce a density ratio close to the engine conditions (DR=1.52). To extend the validity of the survey a comparison between adiabatic effectiveness measurements and a prediction by correlative approach was performed to compare the experimental results with 1D methodologies

Poly(Vinylalcohol-Co-Vinyloleate) for the Preparation of Micelles Enhancing Retinyl Palmitate Transcutaneous Permeation

The amphiphilic properties of poly(vinylalcohol) substituted with oleic acid was evaluated to assess the possibility to prepare polymeric micelles in an aqueous phase containing a hydrophobic core able to host lipophilic drugs such as retinyl palmitate and thereby enhance its transcutaneous absorption in the stratum corneum. The effect of the increased drug absorption suggests the possibility of interaction between the substituted polymer and the components present in the intercorneocyte spaces. Correlations between the drug concentration in the preparative mixture, micelle size, and drug permeation were evaluated to establish the best functional properties of the micellar systems enhancing retinyl palmitate absorption. Transcutaneous absorption increased with decreasing micelle size, and micelle size decreased on decreasing the drug concentration in the preparative mixture

Selective Laser Sintering versus Multi Jet Fusion: A Comprehensive Comparison Study Based on the Properties of Glass Beads-Reinforced Polyamide 12

Selective laser sintering (SLS) and multi jet fusion (MJF) are the most widespreadpowder bed fusion additive manufacturing techniques for fabricating polymericparts since they offer great designflexibility, productivity, and geometricalaccuracy. However, these technologies differ in the thermal energy source usedto melt the powders as well as the innovative use of printing agents featured inthe latter one to promote material consolidation and to avoid thermal bleeding atthe part contours. The use of a single powder made of glass beads-reinforcedpolyamide 12 (PA12/GB) for the fabrication of MJF and SLS samples makespossible a systematic comparison of the printed parts properties. A thoughtfulanalysis of the microstructure and mechanical properties of the samples revealsdifferences and peculiarities between the two technologies. SLS exhibits lowerporosity and higher mechanical performances when the parts are printed alongthe build plane thanks to the powerful heating ensured by the laser. In contrast,MJF samples show higher mechanical isotropy with greatflexural and tensilebehavior for vertically oriented parts. The role of glass beads in the materialbehavior is defined by their mechanical properties, meaning higher rigidity andlower strength compared to neat PA12, and fracture mechanism

Intraductal papillary mucinous neoplasia (IPMN) of the pancreas: the pivotal role of MRI for the differential diagnosis and the choice of treatment

Macrocystic pancreatic tumors seem to play an important role among neoplastic lesions of the pancreas as they sometimes either show a malignant potential or they already have neoplastic foci inside the cystic tumor. Differential diagnosis is a key factor in comparison with other cystic tumors which are not malignant as Serous Cystic Tumors (SCTs) and Mucinous Cystic Tumors (MCTs). So diagnostic imaging has become more and more important. Since May 2009 we have observed more than 200 patients with cystic lesions of the pancreas. All the patients underwent a CholangioPancreato MagneticResonance (CPMR) after an Ultrasound and/or a CT scan. Then we excluded from our study solid lesions, pseudocysts and tumors with clear signs of malignancy. CPMR was sometimes performed also using a secretine test. Finally 51 patients were evaluated and underwent a follow up programme till now. Among these patients we found 34 Intraductal Papillary Mucinous Neoplasia (IPMN), 7 MCTs and 10 SCTs. As we know that all SCTs show a lobulated septate pattern, differential diagnosis with IPMN is mandatory in order to give to the patient the treatment of choice. CPMR revealed in 32 out of 34 IPMN patients a communication between the lesion and the main pancreatic duct (MPD); so this sign, which is patognomonic of IPMN neoplasia, confirmed the diagnosis. All lesions > than 3 cm were resected by surgery (4 MCTs and 3 IPMN). Definitive histology always confirmed preoperative diagnostic imaging. Now the patients are all disease free at follow up. The other 44 patients undergo CPMR every 6 months following a “wait and see” policy. CPMR seems to be fundamental for the diagnostic screening of IPMN. This is a simple, safe and non invasive procedure which allows an early diagnosis and a better chance of cure for this kind of patients

Phase transitions in biological membranes

Native membranes of biological cells display melting transitions of their lipids at a temperature of 10-20 degrees below body temperature. Such transitions can be observed in various bacterial cells, in nerves, in cancer cells, but also in lung surfactant. It seems as if the presence of transitions slightly below physiological temperature is a generic property of most cells. They are important because they influence many physical properties of the membranes. At the transition temperature, membranes display a larger permeability that is accompanied by ion-channel-like phenomena even in the complete absence of proteins. Membranes are softer, which implies that phenomena such as endocytosis and exocytosis are facilitated. Mechanical signal propagation phenomena related to nerve pulses are strongly enhanced. The position of transitions can be affected by changes in temperature, pressure, pH and salt concentration or by the presence of anesthetics. Thus, even at physiological temperature, these transitions are of relevance. There position and thereby the physical properties of the membrane can be controlled by changes in the intensive thermodynamic variables. Here, we review some of the experimental findings and the thermodynamics that describes the control of the membrane function.Comment: 23 pages, 15 figure