Crystal structure of Zn2(HTeO3)(AsO4)

Single crystals of Zn2(HTeO3)(AsO4), dizinc(II) hydroxidodioxidotellurate(IV) oxidoarsenate(V), were obtained as one of the by-products in a hydrothermal reaction between Zn(NO3)2·6H2O, TeO2, H3AsO4 and NH3 in molar ratios of 2:1:2:10 at 483 K for seven days. The asymmetric unit of Zn2(HTeO3)(AsO4) contains one Te (site symmetry m), one As (m), one Zn (1), five O (three m, two 1) and one H (m) site. The ZnII atom exhibits a coordination number of 5 and is coordinated by four oxygen atoms and a hydroxide group, forming a distorted trigonal bipyramid. The hydroxide ion is positioned at a significantly larger distance on one of the axial positions of the bipyramid. The [ZnO4OH] polyhedra are connected to each other by corner-sharing to form ∞ 2[ZnO3/2(OH)1/2O1/1] layers extending parallel to (001). The TeIV atom is coordinated by three oxygen atoms and a hydroxide group in a one-sided manner in the shape of a bisphenoid, revealing stereochemical activity of its 5s 2 electron lone pair. The AsV atom is coordinated by four oxygen atoms to form the tetrahedral oxidoarsenate(V) anion. By corner-sharing, [TeO3OH] and [AsO4] groups link adjacent ∞ 2[ZnO3/2(OH)1/2O1/1] layers along [001] into a three-dimensional framework structure.

EFFECT OF CALCIUM HYDROXIDE-PROPOLIS COMBINATION ON THE NUMBER OF FIBROBLAS CELLS AND ANGIOGENESIS IN WISTAR RATS PULP

Background: The vitality of the pulp must be protected because the pulp contains fibers, cells, and various structures. Pulp vitality can be maintained by pulp capping to stimulate the formation of reparative dentin. The material commonly used for pulp capping is calcium hydroxide. Calcium hydroxide has the disadvantage of causing inflammation and necrosis of the pulp surface. To compensate that, propolis is added because it has the ability as an anti-inflammatory. Purpose: To analyze the increase in the number of fibroblast cells and angiogenesis in the pulp after the application of combination of Calcium hydroxide-propolis compared to the application of Calcium hydroxide.. Methods: This study used 30 samples of wistar rats which were preparated until perforation and then divided into 3 groups. The first group continued with filling with cention, the second group continued with application of calcium hydroxide and filled with cention, and the third group continued with the application of combination of calcium hydroxide and propolis and then being filledwith cention. fibroblast cells and angiogenesis is calculated histopathologically by using compound light microscopeon the 7th day with 400x magnification.Results:Based on the results of the study found a significant difference between the calcium hydroxide group and the calcium hydroxide-propolis group. Increased numbers of fibroblasts and angiogenesis indicate a faster inflammatory process that affects the acceleration of wound healingConclusion: More number of fibroblasts and angiognesis cells found in the pulp after the application of a combination of Calcium hydroxide-propolis compared to the application of Calcium hydroxide

Effect of the Se → Te substitutions on thermal properties of binary Bi2Se3 semiconductor

[Formula: see text] and [Formula: see text] compounds were synthesized and the thermophysical properties were investigated by differential thermal analysis. It was determined that the DSC spectrum of the [Formula: see text] compounds is divided into three regions. The first region was explained by the splitting of water and hydroxide groups in the compound, and the second and third regions with phase transitions. The DSC spectrum of the [Formula: see text] compound was somewhat simpler. The spectrum, divided into two regions, consisted of the first region observed by the decomposition of the water and hydroxide group, and the second region corresponding to the phase transition. Thermodynamic parameters of phase transitions, enthalpy and free energy, were determined.

Clinical and Histological Evaluation of Direct Pulp Capping on Human Pulp Tissue Using a Dentin Adhesive System

Objective. This study presents a clinical and histological evaluation of human pulp tissue responses after direct capping using a new dentin adhesive system. Methods. Twenty-eight caries-free third molar teeth scheduled for extraction were evaluated. The pulps of 22 teeth were mechanically exposed and randomly assigned to 1 of 2 groups: Single Bond Universal or calcium hydroxide. Another group of 6 teeth acted as the intact control group. The periapical response was assayed, and a clinical examination was performed. The teeth were extracted after 6 weeks, and a histological analysis was performed. The pulp status was assessed, and the thickness of the dentin bridge was measured and categorized using a histological scoring system. Results. The clinical phase was asymptomatic for Single Bond Universal patients. Patients in the calcium hydroxide group reported mild symptoms of pain, although the histological examination revealed that dentin bridges with or without limited pulpitis had begun forming in each tooth. The universal adhesive system exhibited nonsignificantly increased histological signs of pulpitis (P>0.05) and a significantly weaker thin mineralized tissue layer (P<0.001) compared with the calcium hydroxide group. Conclusion. The results suggest that Single Bond Universal is inappropriate for human pulp capping; however, further long-term studies are needed to determine the biocompatibility of this agent.

Potential Retinoid X Receptor Agonists for Treating Alzheimer’s Disease from Traditional Chinese Medicine

Alzheimer’s disease is neurodegenerative disorder due to the accumulation of amyloid-βin the brain and causes dementia with ageing. Some researches indicate that the RXR agonist, Targretin, has also been used for treatment of Alzheimer’s disease in mouse models. We investigate the potent candidates as RXR agonists from the vast repertoire of TCM compounds in TCM Database@Taiwan. The potential TCM compounds,β-lipoic acid and sulfanilic acid, had higher potent binding affinities than both 9-cis-retinoic acid and Targretin in docking simulation and have stable H-bonds with residues Arg316 and some equivalent hydrophobic contacts with residues Ala272, Gln275, Leu309, Phe313, Val342, Ile345, and Cys432 as Targretin. The carboxyl or sulfonyl hydroxide group can form a H-bond with key residue Arg316 in the docking pose, and the phenyl group next to the carboxyl or sulfonyl hydroxide group can form aπinteraction with residue Phe313. Moreover,β-lipoic acid and sulfanilic acid have stable H-bonds with residue Gln275, Ser313, and residue Ala327, respectively, which may strengthen and stabilize TCM candidates inside the binding domain of RXR protein. Hence, we proposeβ-lipoic acid and sulfanilic acid as potential lead compounds for further study in drug development process with the RXR protein against Alzheimer’s disease.

Apexification of Anterior Teeth

Purpose: This study was undertaken to compare the clinical and radiographic effectiveness of Mineral Tri-oxide Aggregate (MTA) and Calcium Hydroxide in apexification of traumatized young permanent incisors. Methods: Thirty permanent incisors with necrotic pulps and open apices were evenly divided into two groups –Group I (MTA group) & Group II (Calcium Hydroxide group) and treated by apexification. The time taken for apical barrier formation was analyzed. In MTA group, obturation using gutta-percha points was done after 24 hours, whereas in Calcium Hydroxide group obturation was carried out after radiographic confirmation of an apical barrier. Follow up evaluation (clinical and radiographic) was carried out at- 3, 6, 9 and 12 months. Results: The mean time taken for barrier in Group I was 4.50 ± 1.56 months whereas for Group II was 7.93 ± 2.53 months (p value- 0.0002). Radiographic evidence of mean time taken for completion of lamina dura in Group I was 4.07 ± 1.49 months whereas the time period for Group II was 6.43 ± 2.59 months (p value- 0.0067). Conclusion: MTA demonstrated good success and an effective option for apexification with the advantage of reduced treatment time, good sealing ability, biocompatible and provides barrier for immediate obturation.

Histologic evaluation of pulpotomy performed with ethyl-cyanoacrylate and calcium hydroxide

The aim of this study was to evaluate histological aspects of the pulp-dentin complex of dogs submitted to pulpotomy and capped with ethyl-cyanoacrylate and calcium hydroxide. Thirty dog teeth were divided into 2 groups of 15 as follows: Group 1 - ethyl-cyanoacrylate; Group 2 - calcium hydroxide. The pulpotomies were carried out following all of the treatment precautions recommended for dogs. After 30 days the specimens were submitted to histological preparation and were then blindly evaluated by a histologist. Data were analyzed statistically by the Fisher exact test, comparing the two groups. After 30 days, the presence of a hard tissue barrier was observed in 83.3% of Group 1, and in 100% of Group 2 (p = 0.478). A continuous hard tissue barrier was observed in 50% of the ethyl-cyanoacrylate group and 75% of the calcium hydroxide group (p = 0.652). It can be concluded that both materials induced hard tissue barrier formation, but Group 2 had a higher percentage than Group 1, with no significant statistical differences; the differences observed between the different barriers (continuous/non-continuous) were not significant between groups and there was no pulpal necrosis in either group.

Human pulpal response to Mineral Trioxide Aggregate (MTA): A histologic study

The purpose of this study was to study the histologic changes in the dental pulp following pulpotomy with Mineral Trioxide Aggregate (MTA) and Calcium hydroxide. Pulpotomies were performed on premolar teeth that were to be extracted for orthodontic reasons. The radicular pulp was capped with either MTA or Calcium hydroxide and restored with IRM. The teeth were extracted at 4 and 8 week intervals, fixed in 10% formalin and then kept in 5% nitric acid for 28 days for demineralization. Longitudinal sections were then prepared and viewed under light microscope.The pulps capped with MTA (at the end of 4 weeks and 8 weeks) showed dentin bridge formation which was more homogenous and continuous with the original dentin when compared to the pulps capped with calcium hydroxide. The pulpal inflammation was also less in the MTA group as compared to the calcium hydroxide group at the end of 4 and 8 weeks.