Search results for " Biophysics"
showing 10 items of 136 documents
Dual-polarity pulse processing and analysis for charge-loss correction in cadmium–zinc–telluride pixel detectors
2018
Charge losses at the inter-pixel gap are typical drawbacks in cadmium–zinc–telluride (CZT) pixel detectors. In this work, an original technique able to correct charge losses occurring after the application of charge-sharing addition (CSA) is presented. The method, exploiting the strong relation between the energy after CSA and the beam position at the inter-pixel gap, allows the recovery of charge losses and improvements in energy resolution. Sub-millimetre CZT pixel detectors were investigated with both uncollimated radiation sources and collimated synchrotron X-rays, at energies below and above the K-shell absorption energy of the CZT material. The detectors are DC coupled to fast and low…
Clinical effect of diode laser on peri-implant tissues during non-surgical peri-implant mucositis therapy: Randomized controlled clinical study
2019
Background: The aim of this study is to evaluate the response to the non-surgical treatment of peri-implant mucositis using the diode laser as an adjuvant therapy in patients with implant-supported restorations, in terms of clinical variables, with respect to those patients in whom conventional non-surgical therapy is used. Material and Methods: Randomized controlled clinical trial with simple blind 3 months follow-up. Two groups of patients were established, the non-surgical mechanical debridement of the affected implants was performed in the control group (n = 34) and the diode laser therapy was also performed in the test group (n = 34). The implant was considered the study subject; the v…
Hands On: Using Tryptophan Fluorescence Spectroscopy to Study Protein Structure
2019
Fluorescence spectroscopy is well suited to obtain information about the structure and function of proteins. The major advantage of this spectroscopic technique is the pronounced dependence of the fluorescence emission characteristics of fluorophores on their distinct local environment and the rather inexpensive equipment required. In particular, the use of intrinsic tryptophan fluorescence offers the possibility to study structure and function of proteins without the need to modify the protein. While fluorescence spectroscopy is technically not demanding, a number of factors can artificially alter the results. In this article, we systematically describe the most common applications in fluo…
Generation of oxysterols formed by free radicals and enzymes by electrochemical oxidation
2016
International audience; It is commonly accepted that cholesterol oxide derivatives, also named oxysterols, are 27 carbon-atom molecules deriving either from enzymatic and non-enzymatic oxidation of cholesterol. Most of these compounds can be synthesized by more or less difficult and time consuming chemical reactions, and some of them have been discovered before the identification of the enzymes [mainly cytochrome P450 enzymes (CYP enzymes)] involved in their biosynthesis. A wide range of biological activities depends on oxysterols. Some oxysterols are also involved in the synthesis of cholesterol metabolites which have various properties. The paper by Weber et al. in this issue of European …
The effect of photodynamic therapy and polymer solution containing nano-particles of Ag /ZnO on push-out bond strength of the sealers AH-Plus and MTA…
2017
BACKGROUND The aim of this in vitrostudy was to examine and compare the effect of photodynamic therapy and solution containing nano particles Ag/ZnO on adhesion of endodontic sealers to dentinal walls of human root canal. MATERIAL AND METHODS Ninty single-rooted human teeth were selected and their clinical crown was cut from the cemento-enamel junction zone. Canals were prepared by RaCe rotary system and the smear layer was removed using 17% EDTA and 5.25% NaOCl. Samples were randomly divided into two groups of AH Plus and MTA Fillapex based on the sealer type and each group based on antimicrobial method was divided into two sub-groups of photodynamic therapy and polymer containing nano par…
"The human use of human beings": Interdisciplinarity, transdisciplinarity and all that in biophysics and beyond.
2017
Abstract Biophysics, just by looking at its name, indicates an interdisciplinary scientific activity, although the notion of interdisciplinarity, as such, seems to be not widely or specifically discussed by biophysicists. The same seems to have happened as well in the early stages of the development of cybernetics, notably in Norbert Wiener's writings. This situation seems to contrast with what has happened in subsequent developments of cybernetics ideas, notably in general system theory and cognitive sciences. After a few general reflections on the notion of interdisciplinarity, its sophisticated variants and the path leading to the birth of cognitive science, we shall refer to Wiener's th…
UVER and UV index at high altitude in Northwestern Argentina
2016
Measurements of ultraviolet erythemal radiation (UVER) made during two years at three sites located at altitudes over 1000 m a.s.l. in Northwestern Argentina (Salta, San Carlos, and El Rosal) have been used to estimate and analyze the UV Index (UVI) and the cumulative doses at these locations. For the UVER irradiance, data of January (maximum values) and June (minimum values) have been analyzed as representative of the year for all locations. The UVI reaches extreme (> 11) values in > 20% of the analyzed days in Salta (1190 m a.s.l.), while these are reached in San Carlos (1611 m a.s.l.) and El Rosal (3355 m a.s.l.) in > 40% of the analyzed days. Finally, the cumulative doses over an averag…
Techniques to Analyze sRNA Protein Cofactor Self-Assembly In Vitro
2018
Post-transcriptional control of gene expression by small regulatory noncoding RNA (sRNA) needs protein accomplices to occur. Past research mainly focused on the RNA chaperone Hfq as cofactor. Nevertheless, recent studies indicated that other proteins might be involved in sRNA-based regulations. As some of these proteins have been shown to self-assemble, we describe in this chapter protocols to analyze the nano-assemblies formed. Precisely, we focus our analysis on Escherichia coli Hfq as a model, but the protocols presented here can be applied to analyze any polymer of proteins. This chapter thus provides a guideline to develop commonly used approaches to detect prokaryotic protein self-ass…
Effect of in-office bleaching gels with calcium or fluoride on color, roughness, and enamel microhardness
2019
Background Commercial bleaching gels with remineralizing agents were developed to reduce the adverse effects of dental bleaching. The present study evaluated the effects on teeth of in-office bleaching gels containing 35-40% hydrogen peroxide (HP) with Calcium (Ca) or Fluoride (F). Material and methods Bovine enamel/dentin blocks (4x4x2.5 mm) were randomly divided into the following groups (n=12): no treatment (control); 35% HP (Whiteness HP, FGM); 35% HP with Ca (Whiteness HP Blue, FGM); 40% HP with F (Opalescence Boost, Ultradent). The specimens were analyzed for color (ΔL*, Δa*, Δb*, and ΔE), roughness (Ra), and Knoop microhardness (KHN). The color and KHN data were submitted to ANOVA an…
Extensive osteonecrosis of the maxilla caused by bisphosphonates: Report of a rare case
2019
Bisphosphonates are drugs indicated for the treatment of bone metabolic diseases or malignant hypercalcemia. They are generally well-tolerated drugs, however, recent reports have described osteonecrosis of the jaw bones as a potentially serious complication related to the long-term use of these drugs. We report a case of severe osteonecrosis in a 52-years-old white woman that was taking bisphosphonates (zoledronic acid and alendronate) for the management of osteoporosis. Following a long exposure to these drugs and after being subjected to multiples exodontias, developed bisphosphonate-related osteonecrosis of the jaw compromising the whole maxilla and that extended toward the base of skull…