Thermal,morphostructural and spectrometric characterization of an antibacterial kaolinite-based filter modified with silver for water treatment

Journal of Thermal Analysis and Calorimetry - The aim of this work is to synthesize and characterize a new structured silver–clay dried, calcined or sintered at different temperatures...     

In Vivo Biological Behavior of Polymer Scaffolds of Natural Origin in the Bone Repair Process

Autologous bone grafts, used mainly in extensive bone loss, are considered the gold standard treatment in regenerative medicine, but still have limitations mainly in relation to the amount of bone available, donor area, morbidity and creation of additional surgical area. This fact encourages tissue engineering in relation to the need to develop new biomaterials, from sources other than the individual himself. Therefore, the present study aimed to investigate the effects of an elastin and collagen matrix on the bone repair process in critical size defects in rat calvaria. The animals (Wistar rats, n = 30) were submitted to a surgical procedure to create the bone defect and were divided into three groups: Control Group (CG, n = 10), defects filled with blood clot; E24/37 Group (E24/37, n = 10), defects filled with bovine elastin matrix hydrolyzed for 24 h at 37 °C and C24/25 Group (C24/25, n = 10), defects filled with porcine collagen matrix hydrolyzed for 24 h at 25 °C. Macroscopic and radiographic analyses demonstrated the absence of inflammatory signs and infection. Microtomographical 2D and 3D images showed centripetal bone growth and restricted margins of the bone defect. Histologically, the images confirmed the pattern of bone deposition at the margins of the remaining bone and without complete closure by bone tissue. In the morphometric analysis, the groups E24/37 and C24/25 (13.68 ± 1.44; 53.20 ± 4.47, respectively) showed statistically significant differences in relation to the CG (5.86 ± 2.87). It was concluded that the matrices used as scaffolds are biocompatible and increase the formation of new bone in a critical size defect, with greater formation in the polymer derived from the intestinal serous layer of porcine origin (C24/25).     

Isolation of Bisphenol A-Tolerating/degrading Shewanella haliotis Strain MH137742 from an Estuarine Environment

Applied Biochemistry and Biotechnology - The human exposure to bisphenol A (BPA) occurs frequently. Once, this compound was one of the highest volume chemicals produced worldwide and used as a...     

The liquid-crystalline properties of bis[N-[[4-[4-(alkoxy)benzoyloxy]2-hydroxyphenyl]methylene]alkanamino] complexes of Cu(II), Pd(II) and Ni(II). A general view

The thermotropic liquid-crystalline phase behaviour of a homologous set of bis[N-[[4-[4-(alkoxy)benzoyloxy]2-hydroxyphenyl]methylene]alkanamino] copper(II) complexes is examined. New data are reported and taken into account in addition to those previously reported in this Journal. The influence of alkoxy and alkanamine groups on the nature and stability of the mesophase is underlined. As a general trend, with some notable exception, smectic (C type) mesomorphism is favoured by longer alkoxy and alkanamine chains. Data concerning some Pd(II) and Ni(II) homologous complexes are also reported. The mesophase stability (nematic phase) is higher for palladium and nickel complexes than for the copper containing homologues.     

Internal conical refraction of Bessel light beams

The internal conical refraction of a Bessel beam of arbitrary order is studied theoretically. It is shown that a beam of the order m of arbitrary polarization in the general case is partially converted to Bessel beams of the order m ± 1 with orthogonal circular polarizations. Conditions for complete conversion of a beam of the order m to a Bessel beam of the order m?1 or m+1 are determined.     

A highly active fungal β-glucosidase

A highly active thermostable β-glucosidase was purified to homogeneity from a strain ofTrichoderma sp. The enzyme was an extracellular glycoprotein and showed hydrolytic activity toward several β-glucosides. Cellobiose was found to be the substrate of choice for this enzyme. This finding could suggest future technological applications of the purified protein.     

Specific features of vowel-like signals of white whales

The set of acoustic signals of White-Sea white whales comprises about 70 types of signals. Six of them occur most often and constitute 75% of the total number of signals produced by these animals. According to behavioral reactions, white whales distinguish each other by acoustic signals, which is also typical of other animal species and humans. To investigate this phenomenon, signals perceived as vowel-like sounds of speech, including sounds perceived as a “bleat,” were chosen A sample of 480 signals recorded in June and July, 2000, in the White Sea within a reproductive assemblage of white whales near the Large Solovetskii Island was studied. Signals were recorded on a digital data carrier (a SONY minidisk) in the frequency range of 0.06–20 kHz. The purpose of the study was to reveal the perceptive and acoustic features specific to individual animals. The study was carried out using the methods of structural analysis of vocal speech that are employed in lingual criminalistics to identify a speaking person. It was demonstrated that this approach allows one to group the signals by coincident perceptive and acoustic parameters with assigning individual attributes to single parameters. This provided an opportunity to separate conditionally about 40 different sources of acoustic signals according to the totality of coincidences, which corresponded to the number of white whales observed visually. Thus, the application of this method proves to be very promising for the acoustic identification of white whales and other marine mammals, this possibility being very important for biology.     

On nash theory of Arc structure of singularities

Sunto Si ha l'intenzione d'incominciare lo studio sistematico della teoria abbozzata da John Nash circa venticinque anni fa, dove si associa a una varietà algebrica singolare X spazi i cui ponti corrispondono genericamente a troncature di certi rami analitici parametrizati su X. In questo articolo si presentano accuratamente i fondamenti della teoria. Inoltre, con questi metodi (e nozioni della teoria della equisingolarità per le curve sghembe) s'introducono nuovi invarianti di una singolarità, si spera di studiarli più accuratamente in futuri lavori.     

Crystal and molecular structure of thiamine monochloride

The crystal and molecular structure of thiamine monochloride (C₁₂H₁₇N₄OSCl) was determined by X-ray diffraction and refined to a finalR value of 0.042. The compound crystallizes in the monoclinic system, space groupP2₁/a, with cell constantsa=18.929(4),b=11.663(2),c=6.376(2) Å and=96.72(8)°. The thiamine molecule is anhydrous and unprotonated, and the torsion angles at the methylene carbon show that it possesses anF conformation. The dihedral angle value of 84.16(6)° between thiazolium and pyrimidine rings is in the normal range found for the thiamine withF conformation, protonated or not, hydrated or not. Thiamine therefore has the same conformation notwithstanding protonation or hydration, with the rings similarly oriented in all the crystal structures containing thiamine.     

Internal flexibility of cardiac myosins

Conventional and saturation transfer electron paramagnetic resonance spectroscopy (EPR and ST EPR) and differential scanning calorimetry (DSC) were used to study the motional dynamics and segmental flexibility of cardiac myosins.Cardiac myosins isolated from bovine and human heart muscle were spin-labelled with isothiocyanate- or maleimide-based probe molecules at the reactive sulfhydryl sites (Cys-697 and Cys-707) of the motor domain. The maleimide probe molecules attached to human cardiac myosin rotated with an effective rotational correlation time of 33 ns which was at least eight times shorter than the rotational correlation time of the same label on skeletal myosin (260 ns). In the presence of MgADP and MgADP plus orthovanadate, flexibility changes in the multisubunit structure of myosins were detected, but this did not lead to changes of the overall rotational property of the myosin heads. Significant difference in the internal flexibility was detected on myosin samples isolated from ischemic tissue, the rotational correlation time decreased to 25 ns.DSC measurements supported the view that addition of nucleotides produced additional loosening in the multisubunit structure of cardiac myosin. It is postulated that there is an intersite communication between the nucleotide binding domain and the 20 kDa subunit where the reactive thiol sites are located.This work was supported by grants from the National Research Foundation (OTKA T 017099) and Ministry of Social Welfare (ETT 737/1993). The Bruker ESP 300 E spectrometer and the SETARAM Micro DSC-II used in the experiments were purchased with funds provided by the National Research Foundation Grants CO-123 and CO-272. The computer (PC-386) was supported by POPEX Ltd., Pécs, Hungary. The authors thank to Prof. Dr. K. Hideg (Central Research Laboratory) for providing the iodoacetamide spin label.