Optimization of Functional Toothpaste Formulation Containing Nano-Hydroxyapatite and Birch Extract for Daily Oral Care.

This research work aims to develop functional toothpastes with combined enamel remineralization and antibacterial effects using nano-hydroxyapatites (nHAPs) and birch extract. Eleven toothpastes (notated as P1-P11) were designed featuring different concentrations of birch extract and a constant concentration of pure nHAPs or substituted nHAPs (HAP-5%Zn, HAP-0.23%Mg-3.

Impact of Arieş River Contaminants on Algae and Plants.

The Arieş River (Western Romania) represents one of the most important affluents of the Mureş River, with great significance in the Mureş Tisza basin. The environmental quality of the Arieş basin is significantly affected by both historic mining activities and contemporary impacts. Thus, an evaluation of the effects of the main contaminants found in water (organochlorine pesticides-OCPs, monocyclic aromatic hydrocarbons-MAHs, polycyclic aromatic hydrocarbons-PAHs, and metals) on cyanobacteria and plants was performed.

Remineralization Induced by Biomimetic Hydroxyapatite Toothpastes on Human Enamel.

This work aimed to compare the effect of four new toothpastes (P1-P4) based on pure and biomimetic substituted nano-hydroxyapatites (HAPs) on remineralization of human enamel. Artificially demineralized enamel slices were daily treated for ten days with different toothpastes according to the experimental design. Tooth enamel surfaces were investigated using atomic force microscope (AFM) images and surface roughness (Ra) determined before and after treatment.

Double-Network Chitosan-Based Hydrogels with Improved Mechanical, Conductive, Antimicrobial, and Antibiofouling Properties.

In recent years, the antimicrobial activity of chitosan-based hydrogels has been at the forefront of research in wound healing and the prevention of medical device contamination. Anti-infective therapy is a serious challenge given the increasing prevalence of bacterial resistance to antibiotics as well as their ability to form biofilms. Unfortunately, hydrogel resistance and biocompatibility do not always meet the demands of biomedical applications.

Characterization of halophilic bacterial communities in Turda Salt Mine (Romania).

Halophilic organisms are having adaptations to extreme salinity, the majority of them being Archaean, which have the ability to grow at extremely high salt concentrations, (from 3 % to 35 %). Level of salinity causes natural fluctuations in the halophilic populations that inhabit this particular habitat, raising problems in maintaining homeostasis of the osmotic pressure. Samples such as salt and water taken from Turda Salt Mine were analyzed in order to identify the eco-physiological bacterial groups.

Unexpected formation of N-(1-(2-aryl-hydrazono)isoindolin-2-yl)benzamides and their conversion into 1,2-(bis-1,3,4-oxadiazol-2-yl)benzenes.

Reaction between ortho-phthalaldehyde and various aroylhydrazines unexpectedly yields N-(1-(2-aryl-hydrazono)isoindolin-2-yl)benzamides as major products along with the predictable 1,2-bis-aroylhydrazones. NMR investigation of the major reaction products indicate the presence of a mixture of geometrical isomers, in various ratios. Single crystal X-ray diffraction confirms the proposed structure and indicates a Z configuration of the C═N double bond substitutents.

Mean field model for ferromagnetic nanowire arrays based on a mechanical analogy.

Nanowire arrays have typical distributions of coercive and interaction fields, as revealed in experiments by means of the first-order reversal curve (FORC) method. In an axial applied field, each nanowire is subjected to a state dependent interaction field created by all wires from the array, which strongly influences the switching fields. A mean field model based on Preisach-Krasnosel'skii-Pokrovskii (PKP) hysterons is able to explain the interplay between interactions and critical fields in nanowire arrays and the subtle way in which switching fields are emphasized in FORC diagrams.

Poly-β-hydroxybutyrate accumulation in bacterial consortia from different environments.

The aim of the present study was to examine soil samples from various vegetation zones in terms of physicochemical properties, microbial communities, and isolation and identification (by polymerase chain reaction and transmission electron microscopy) of bacteria producing poly-β-hydroxybutyrates (PHBs). Soil samples were analysed originating from zones with heterogeneous environmental conditions from the Romanian Carpathian Mountains (mountain zone with alpine meadow, karstic zone with limestone meadow, hill zone with xerophilous meadow, and flood plain zone with hygrophilic meadow). Different bacterial groups involved in the nitrogen cycle (aerobic mesophilic heterotrophs, ammonifiers, denitrifiers, nitrifiers, and free nitrogen-fixing bacteria from Azotobacter genus) were analysed.

Glycine fluoromethylketones as SENP-specific activity based probes.

We report here the synthesis and biochemical properties of a new peptidyl activity-based probe 1 for SUMO proteases, SENPs. The activity-based probe has at its C terminus a glycine-derived fluoromethylketone moiety as a reactive group designed to target the active-site cysteine of SENPs. Based on a study of the interactions between SENPs and SUMOs, we introduced further design elements that allow the activity-based probe to selectively target SENPs at low micromolar to high nanomolar concentrations.

Metal ion mediated self-assembly directed formation of protein arrays.

Self-assembled inorganic-protein arrays with well-defined and controllable size and structure were obtained through the Fe(II) complexation of protein-conjugated terpyridine units (ligand). The atom-level control of the ligand is obtained through residue-specific conjugation between the complexing unit (terpy) containing an activity-based probe and a corresponding active enzyme (papain). The Fe(II)-based self-assembly performed on this unique building block (ligand) leads to chemical species of unprecedented constitution.

Physico-chemical and biological studies on water from Aries River (Romania).

Our work was focused on physico-chemical and biological characteristics of Aries River, one of the largest rivers from Romania. Water samples were collected from 11 sites along Aries River course. We have measured de (18)O and D isotopic composition of Aries River water in these locations and correlated these data with the isotopic composition of aquatic plants and with the pollution degree.

Protein-inorganic array construction: design and synthesis of the building blocks.

Herein we describe the design and synthesis of the first series of di-functional ligands for the directed construction of inorganic-protein frameworks. The synthesized ligands are composed of a metal-ion binding moiety (terpyridine-based) conjugated to an epoxysuccinyl peptide, known to covalently bind active cysteine proteases through the active-site cysteine. We explore and optimize two different conjugation chemistries between the di-functionalized metal-ion ligand and the epoxysuccinyl-containing peptide moiety: peptide-bond formation (with limited success) and Cu(I)-catalysed click chemistry (with good results).

Growth of pea epicotyl in low magnetic field: implication for space research.

A magnetic field is an inescapable environmental factor for plants on the earth. However, its impact on plant growth is not well understood. In order to survey how magnetic fields affect plant, Alaska pea seedlings were incubated under low magnetic field (LMF) and also in the normal geo-magnetic environment.