A comprehensive benchmark investigation of quantum chemical methods for carbocations.

The application of various density functional approximations (DFAs) and an emphasis on popular methods without any consensus have prevailed in computational studies dedicated to carbocations. More importantly, an extensive and rigorous benchmark investigation on density functionals for the class is still lacking. To close this gap, we present a comprehensive benchmark study of quantum chemical methods on a series of classical and nonclassical carbocations, the CARBO33 dataset.

Do Double-Hybrid Exchange-Correlation Functionals Provide Accurate Chemical Shifts? A Benchmark Assessment for Proton NMR.

A benchmark density functional theory (DFT) study of H NMR chemical shifts for data sets comprising 200 chemical shifts, including complex natural products, has been carried out to assess the performance of DFT methods. Two new benchmark data sets, NMRH33 and NMRH148, have been established. The meta-GGA revTPSS performs remarkably well against the NMRH33 benchmark set (mean absolute deviation (MAD), 0.

In vitro evaluation of the protective effects of plant extracts against amyloid-beta peptide-induced toxicity in human neuroblastoma SH-SY5Y cells.

Alzheimer's disease (AD) is the most common form of dementia and has no cure. Therapeutic strategies focusing on the reduction of oxidative stress, modulation of amyloid-beta (Aβ) toxicity and inhibition of tau protein hyperphosphorylation are warranted to avoid the development and progression of AD. The aim of this study was to screen the crude extracts (CEs) and ethyl-acetate fractions (EAFs) of Guazuma ulmifolia, Limonium brasiliense, Paullinia cupana, Poincianella pluviosa, Stryphnodendron adstringens and Trichilia catigua using preliminary in vitro bioassays (acetylcholinesterase inhibition, antioxidant activity and total polyphenol content) to select extracts/fractions and assess their protective effects against Aβ25-35 toxicity in SH-SY5Y cells.

Effects of folic acid on the antiproliferative efficiency of doxorubicin, camptothecin and methyl methanesulfonate in MCF-7 cells by mRNA endpoints.

There is a lack of consensus on whether the role of folate in cancer cells is protective or harmful. The use of folates in combination with cancer-targeting therapeutic regimens requires detailed information to ensure their safe and proper use. Therefore, we evaluated the effects of folic acid (FA) in combination with the chemotherapeutic compounds doxorubicin (DXR), camptothecin (CPT) and methyl methanesulfonate (MMS) on the growth of MCF-7 cells.

RNAm expression profile of cancer marker genes in HepG2 cells treated with different concentrations of a new indolin-3-one from Pseudomonas aeruginosa.

The present study tested the effects of a newly identified indolin-3-one compound (compound 1), produced by Pseudomonas aeruginosa, on HepG2 cells. The MTT assays demonstrated decreased metabolic activities in HepG2 cells treated with compound 1, with dose- and time-dependent intensifying effect, starting at a concentration of 40 µM. The IC after 24, 48, 72, and 96 h treatments were 41.

Expression of cyp1a induced by benzo(A)pyrene and related biochemical and genotoxic biomarkers in the neotropical freshwater fish Prochilodus lineatus.

The goal of this work was to design specific cyp1a primers for the fish Prochilodus lineatus to study the expression of this gene and its relation to the activity of biotransformation phase I enzyme (ethoxyresorufin O-deethylase - EROD) and genotoxic damage after 6 and 24 h of benzo(a)pyrene (B(a)P) intraperitoneal injection. In comparison to fish injected only with canola oil (vehicle), the expression of cyp1a and EROD activity both in the liver and gills were significantly higher after 6 and 24 h of B(a)P injection. A significant increase in DNA damage was detected in liver and blood cells after 6 h of B(a)P injection and in the gill cells after both times, probably caused by intermediate metabolites of B(a)P.

On the virtues of automated quantitative structure-activity relationship: the new kid on the block.

Quantitative structure-activity relationship (QSAR) has proved to be an invaluable tool in medicinal chemistry. Data availability at unprecedented levels through various databases have collaborated to a resurgence in the interest for QSAR. In this context, rapid generation of quality predictive models is highly desirable for hit identification and lead optimization.

Phytochemical study and evaluation of cytotoxicity, mutagenicity, cell cycle kinetics and gene expression of Bauhinia holophylla (Bong.) Steud. in HepG2 cells in vitro.

Bauhinia holophylla (Bong.) Steud. (Fabaceae) is a plant used in Brazilian folk medicine to treat diabetes and inflammation.

Development of a pharmacophore for cruzain using oxadiazoles as virtual molecular probes: quantitative structure-activity relationship studies.

Chagas's is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. According to the World Health Organization, 7 million people are infected worldwide leading to 7000 deaths per year. Drugs available, nifurtimox and benzimidazole, are limited due to low efficacy and high toxicity.

Effects of indirubin and isatin on cell viability, mutagenicity, genotoxicity and BAX/ERCC1 gene expression.

Context: Indigofera suffruticosa Miller (Fabaceae) and I. truxillensis Kunth produce compounds, such as isatin (ISA) and indirubin (IRN), which possess antitumour properties. Their effects in mammalian cells are still not very well understood.

Risk Assessment via Metabolism and Cell Growth Inhibition in a HepG2/C3A Cell Line Upon Treatment with Arpadol and its Active Component Harpagoside.

Harpagophytum procumbens (Hp) has been used as antiinflammatory and analgesic agent for the treatment of rheumatic diseases. The principal active component of Hp is harpagoside (HA). We tested the toxicity of this new therapeutic agent in a hepatic cell line (HepG2/C3A).

Effects of radiant exposure and wavelength spectrum of light-curing units on chemical and physical properties of resin cements.

Objectives: In this study, we evaluated the influence of different radiant exposures provided by single-peak and polywave light-curing units (LCUs) on the degree of conversion (DC) and the mechanical properties of resin cements.

Materials And Methods: Six experimental groups were established for each cement (RelyX ARC, 3M ESPE; LuxaCore Dual, Ivoclar Vivadent; Variolink, DMG), according to the different radiant exposures (5, 10, and 20 J/cm) and two LCUs (single-peak and polywave). The specimens were made (7 mm in length × 2 mm in width × 1 mm in height) using silicone molds.

Transferring Conditioned Partially Edentulous Ridge Form to a Master Cast.

Gingival conditioning techniques in prosthodontics aim to overcome bone and soft-tissue defects that often compromise the outcome of restorations in terms of esthetics, function, and biocompatibility. Whatever the technique used, it is essential to reproduce a regular concave gingival outline in order to recreate the natural aspect of the relationship between teeth and gingiva, eliminating black triangles. Transferring the details of the conditioned soft tissue to the laboratory technician with precision may be challenging.

Advances and Progress in Chagas Disease Drug Discovery.

Chagas disease represents a serious burden for millions of people worldwide. Transmitted by the protozoan parasite Trypanosoma cruzi, this neglected tropical disease causes more than 10,000 deaths each year and is the main cause of heart failure in Latin America, where it is endemic. Although most cases are concentrated in Latin American countries, Chagas disease has been increasingly reported in non-endemic regions, where the low level of public awareness on the subject contributes to the growing prevalence of the disease.

Cellulose acetate butyrate/poly(caprolactonetriol) blends: Miscibility, mechanical properties, and in vivo inflammatory response.

This study reports the results of the characterization of cellulose acetate butyrate and polycaprolactone-triol blends in terms of miscibility, swelling capacity, mechanical properties, and inflammatory response in vivo. The cellulose acetate butyrate film was opaque and rigid, with glass transition (T g ) at 134℃ and melting temperature of 156℃. The cellulose acetate butyrate/polycaprolactone-triol films were transparent up to a polycaprolactone-triol content of 60%.

Genetic polymorphisms in glutathione (GSH-) related genes affect the plasmatic Hg/whole blood Hg partitioning and the distribution between inorganic and methylmercury levels in plasma collected from a fish-eating population.

This study aims to evaluate the effects of polymorphisms in glutathione (GSH-) related genes (GSTM1, GSTT1, GSTP1, GCLM, and GCLC) in the distribution of Hg in the blood compartments in humans exposed to methylmercury (MeHg). Subjects (n = 88), exposed to MeHg from fish consumption, were enrolled in the study. Hg species in the plasma compartment were determined by LC-ICP-MS, whereas genotyping was performed by PCR assays.

Assessment of acid neutralizing capacity in cola-based drinks and energy beverages by artificial saliva.

Objective: To assess the pH of regular and light cola-based drinks and energy drinks, and examine the acid neutralizing capacity by the addition of artificial saliva.

Materials And Methods: Ten packages of each product purchased locally at different stores were evaluated. The pH was measured by a pH-electrode calibrated in standard buffer solutions.

Histometric study of resorption on replanted teeth with enamel matrix-derived protein.

Background: Enamel matrix-derived proteins (Emdogain) stimulate the proliferation of periodontal ligament cells, contributing to their regeneration.

Aim: This study was to perform histometric assessment of root surface resorption in replanted teeth with the use of Emdogain®.

Materials And Methods: Male Wistar rats (Rattus norvegicus), weighing 180 to 200 gm, were anesthetized, subjected to extraction of the upper right incisor tooth, which was then replanted into the alveoli with the following treatment: (a) control group--tooth with root canal filled with calcium hydroxide paste and (b) treated group--tooth with root canal filled with enamel matrix-derived protein.

Effect of water storage on bond strength of self-adhesive resin cements to zirconium oxide ceramic.

Purpose: To evaluate the microshear bond strength of resin cements to yttrium-stabilized tetragonal zirconium oxide surfaces after water storage for 24 h or 1 year.

Materials And Methods: Four self-adhesive (BisCem, G-Cem, RelyX Unicem, SeT) and one conventional resin cement (RelyX ARC) were tested. The materials were mixed and inserted in tubes (0.

Vascular leiomyoma in the oral cavity.

The aim of this study was to examine a case report of vascular leiomyoma located in the oral mucosa of the oral cavity. Vascular leiomyoma is a benign tumor arising from smooth muscle. One factor that makes vascular leiomyomas in the oral cavity rare is that there is little smooth muscle in the mouth.

Analysis of the interfacial micromorphology and bond strength of adhesive systems to Er:YAG laser-irradiated dentin.

Unlabelled: This study evaluated the effects of different parameters of dentin irradiation with erbium -doped yttrium aluminum garnet (Er:YAG) laser on bond strength to dentin and analyzed the ultramorphological characteristics of resin-laser-irradiated dentin interfaces using a transmission electron microscope (TEM). Dentin surfaces were abraded with SiC paper (600 grit) or Er:YAG laser-irradiated (120/4, 140/6, 180/4, or 200/6 mJ/Hz). Three adhesive systems were tested: Single Bond Plus (3M ESPE), Clearfil Protect Bond (Kuraray Med.

Bond strength of adhesive systems to Er,Cr:YSGG laser-irradiated dentin.

Objective: The purpose of this study was to evaluate the effects of Er,Cr:YSGG laser irradiation and different adhesive procedures on bond strength of two bonding agents to dentin.

Background Data: Studies have shown that laser-irradiated dentinal tissue yields lower bond strengths than does nonirradiated dentin. In this study, different treatment methods of laser irradiating dentin were studied to enhance the bond strength of bonding agents to nonirradiated dentin.

Effects from exposure to dental amalgam on systemic mercury levels in patients and dental school students.

Objectives: The purpose of this study was to evaluate the systemic mercury levels in urine of patients and dental school students caused by exposure to silver amalgam. It is currently believed that occupational exposure shows the highest rate of potential for poisoning by mercury. Dental professionals are part of that quota, introducing concerns regarding the handling of dental amalgam.

Micromorphology of resin-dentin interfaces using one-bottle etch&rinse and self-etching adhesive systems on laser-treated dentin surfaces: a confocal laser scanning microscope analysis.

Background And Objectives: This study evaluated the hybrid layer (HL) morphology created by three adhesive systems (AS) on dentin surfaces treated with Er:YAG laser using two irradiation parameters.

Study Design: Occlusal flat dentin surfaces of 36 human third molars were assigned into nine groups (n = 4) according to the following ASs: one bottle etch&rinse Single Bond Plus (3M ESPE), two-step Clearfil Protect Bond (Kuraray), and all-in-one S(3) Bond (Kuraray) self-etching, which were labeled with rhodamine B or fluorescein isothiocyanate-dextran and were applied to dentin surfaces that were irradiated with Er:YAG laser at either 120 (38.7 J/cm(2)) or 200 mJ/pulse (64.

Unravelling the stereoselectivity in 6-exo-trig radical cyclization of alpha,beta-unsaturated ester-tethered sugars. A tale of two stereocenters.

A computational investigation on the origin of the stereoselectivity of 6-exo-trig radical cyclization of alpha,beta-unsaturated ester-tethered sugars has revealed that a boat-like transition state, which keeps the ester in a planar conformation, holds the chiral information. Following this model, the stereocenter to which the ester functionality is connected reports the chirality to the newly formed stereocenter via a 1,4-transfer mechanism.