Influence of different processing techniques for prosthetic acrylic resins in the surface roughness parameters: a research article.

BACKGROUND: Different processing techniques are employed to obtain poly (methyl methacrylate) (PMMA) with consistent surface quality in terms of topography and tribological function. The purpose of this research is to evaluate its influence on the surface height distribution. METHODS: In this research, samples of conventional and CAD/CAM acrylic resins were prepared. The following surface roughness parameters were extracted from the profilometric readings: arithmetic mean roughness (Pa), skewness (Psk) and kurtosis (Pku). Profilometric profiles were additionally obtained. RESULTS: The average roughness (Pa) with the conventional technique was significantly higher compared to CAD/CAM (t = 4.595; P < 0.001). Heat-cured resins presented the highest mean Pa (F = 6.975; P = 0.06). Heat-cured and milled resins show lower coefficient variation (CV) values, indicating more consistent surface finishing. The surface profiles revealed distinct characteristics in terms of skewness and kurtosis. CONCLUSIONS: The surface processing method, chemical composition and resin type significantly influence the surface finishing of the resin. The CAD/CAM resins exhibited superior results in terms of surface arithmetic mean roughness (Pa). However, heat-cured resin revealed to present the better surface consistency.

Analyzing Linear and Angular Deviations After Guided Surgery for Dental Implant Placement: A Preliminary Study.

PURPOSE: This study aimed to assess the accuracy and precision of prosthetically-driven implant placement achieved through static computer-aided implant surgery. The primary objective was to analyze the linear and angular deviations of dental implants in patients treated at a university dental clinic. Various types of surgical techniques and templates were utilized to optimize implant positioning. MATERIALS AND METHODS: A total of fiftythree dental implants were included in this study. The implants were positioned using either tooth-supported templates or tooth-tissue-supported templates with fixation pins. Two distinct guided surgery approaches were used, these being pilot drill guided and fully guided. Three-dimensional (3D) data from the implant planning phase was superimposed with the 3D data from the final implant positions using the 'Treatment Evaluation' tool within CoDiagnostix. implant planning software (Straumann AG). This enabled the automatic calculation of deviations in implant placement accuracy. RESULTS: Average angular deviation observed was 3.90 degrees. For linear deviations, the mean 3D deviation at the most coronal point of the implants was 1.04 mm, while at the implant apex it was 1.56 mm. CONCLUSION: This research demonstrates the feasibility of a digital workflow for guided implant surgery, offering a promising treatment option. Nonetheless, it is important to note that deviations do occur, with the apical region of the implant being the most affected area. Care should be taken, particularly in cases of limited bone availability.

Chiral HPLC analysis of venlafaxine metabolites in rat liver microsomal preparations after LPME extraction and application to an in vitro biotransformation study.

A three-phase LPME (liquid-phase microextraction) method for the enantioselective analysis of venlafaxine (VF) metabolites (O-desmethylvenlafaxine (ODV) and N-desmethylvenlafaxine (NDV) in microsomal preparations is described for the first time. The assay involves the chiral HPLC separation of drug and metabolites using a Chiralpak AD column under normal-phase mode of elution and detection at 230 nm. The LPME procedure was optimized using multifactorial experiments and the following optimal condition was established: sample agitation at 1,750 rpm, 20 min of extraction, acetic acid 0.1 mol/L as acceptor phase, 1-octanol as organic phase and donor phase pH adjustment to 10.0. Under these conditions, the mean recoveries were 41% and 42% for (-)-(R)-ODV and (+)-(S)-ODV, respectively, and 47% and 48% for (-)-(R)-NDV and (+)-(S)-NDV, respectively. The method presented quantification limits of 200 ng/mL and it was linear over the concentration range of 200-5,000 ng/mL for all analytes. The validated method was employed to study the in vitro biotransformation of VF using rat liver microsomal fraction. The results demonstrated the enantioselective biotransformation of VF.

In vitro metabolism study of a new nitrosyl ruthenium complex [Ru(NH.NHq)(terpy)NO]3+ nitric oxide donor using rat microsomes.

A new nitrosyl ruthenium complex [Ru(NH.NHq)(terpy)NO](3+) nitric oxide donor was recently developed and due to its excellent vasodilator activity, it has been considered as a potential drug candidate. Drug metabolism is one of the main parameters that should be evaluated in the early drug development, so the biotransformation of this complex by rat hepatic microsomes was investigated. In order to perform the biotransformation study, a simple, sensitive and selective HPLC method was developed and carefully validated. The parameters evaluated in the validation procedure were: linearity, recovery, precision, accuracy, selectivity and stability. Except for the stability study, all the parameters evaluated presented values below the recommended by FDA guidelines. The stability study showed a time-dependent degradation profile. After method validation, the biotransformation study was accomplished and the kinetic parameters were determined. The biotransformation study obeyed the Michaelis-Menten kinetics. The V(max) and K(m) were, respectively, 0.1625+/-0.010 micromol/mg protein/min and 79.97+/-11.52 microM. These results indicate that the nitrosyl complex is metabolized by CYP450.

Stability of vacuum-packed meat from finishing steers fed different inclusion levels of brewer's spent grain.

Brewer's spent grain (BSG) as a partial substitute for corn silage (CS) was evaluated in finishing feedlot steers on the lipid, protein, color, and microbiological stability of vacuum-packed meat for 75 days under refrigerated storage. Twenty steers were distributed in four treatments in a completely randomized design with five replicates each: 50% concentrate + 50% CS; + 35% CS + 15% BSG; + 25% CS + 25% BSG; and 15% CS + 35% BSG for 90 days. After the animals were slaughtered and the carcasses cooled, the Longissimus thoracis muscle was collected for analyzes. The lipid and protein oxidation, color parameters and microbiological stability of the beef although not affected by the diets (P > .05) oscillated throughout the storage time (P < .05). BSG can be included in the finishing diets of beef cattle by up to 35% (dry basis) and as a forage source without adverse effects on beef shelf life.

Enantioselective analysis of oxybutynin and N-desethyloxybutynin with application to an in vitro biotransformation study.

An enantioselective method using liquid-phase microextraction (LPME) followed by HPLC analysis was developed for the determination of oxybutynin (OXY) and its major metabolite N-desethyloxybutynin (DEO) in rat liver microsomal fraction. The LPME procedure was optimized using multifactorial experiments. Under the optimal extraction conditions, the mean recoveries were 61 and 55% for (R)-OXY and (S)-OXY, respectively, and 70 and 76% for (R)-DEO and (S)-DEO, respectively. The validated method was employed to an in vitro biotransformation study using rat liver microsomal fraction. The results demonstrated the enantioselective biotransformation of OXY.

Adequação psicométrica da Richmond Compulsive Buying Scale para a Região Nordeste do Brasil / Adecuación psicométrica de la Richmond Compulsive Buying Scale para la región noreste de Brasil / Psychometric adaptation of the Richmond Compulsive Buying Scale to the Northeast region of Brazil

Resumo Objetivou-se coletar evidências das propriedades psicométricas da Richmond Compulsive Buying Scale (RCBS) em estudantes universitários da Região Nordeste do Brasil. Para isso, foram realizados dois estudos. O Estudo 1 contou com 300 universitários oriundos do Nordeste brasileiro. Predominaram aqueles do sexo feminino (71 %), de universidade particular (67 %) e com média de idade de 23,5 anos (DP = 6,7). Os resultados indicaram uma estrutura empírica sustentável (teste de Kaiser-Meyer-Olkin [KMO] = 0,82), com indicadores psicométricos considerados adequados à mensuração da compra compulsiva. Além disso, uma estrutura unifatorial, constituída por seis itens, que explicaram 51,85 % da variância e alfa de Cronbach = 0,86. Já o Estudo 2 teve como finalidade testar a estrutura fatorial encontrada no Estudo 1. Participaram 279 universitários, a maioria de universidade pública (54,1 %), do sexo masculino (51,3 %) e com média de idade de 23,1 anos (DP = 4,74). Por meio da análise fatorial confirmatoria, foram verificados bons indicadores de ajuste: X2/gl = 2,90; GFI = 0,98; CFI = 0,98; TLI = 0,98; RMSEA = 0,08 (IC 90 % = 04-0,10). Conclui-se que a RCBS apresentou parâmetros psicométricos adequados e é uma medida útil para os futuros estudos sobre a compra compulsiva.

Resumen Se propuso recoger evidencia de las propiedades psicométricas de la Richmond Compulsive Buying Scale (RCBS) en estudiantes universitarios de la región noreste de Brasil. Para ello, se realizaron dos estudios. El Estudio 1 contó con 300 universitarios oriundos del nordeste brasileño. Predominaron aquellos de sexo femenino (71 %), de universidad privada (67 %) y con promedio de edad de 23,5 años (DE = 6,7). Los resultados indicaron una estructura empírica sustentable (test de Kaiser-Meyer-Olkin [KMO] = 0,82), con indicadores psicométricos considerados adecuados a la medición de compra compulsiva. Asimismo, una estructura unifactorial, constituida por seis ítems, que explican el 51,85 % de la varianza y alfa de Cronbach = 0,86. El Estudio 2 tuvo como fin probar la estructura factorial encontrada en el Estudio 1. Participaron 279 universitarios, mayoritariamente de universidad pública (54,1 %), de sexo masculino (51,3 %) y con promedio de edad de 23,1 años (EP = 4,74). Por medio del Análisis Factorial Confirmatorio, fueron verificados buenos indicadores de ajuste: X2/gl = 2,90; GFI = 0,98; CFI = 0,98; TLI = 0,98; RMSEA = 0,08 (IC 90 % = 04-0,10). Se concluye que la RCBS presentó parámetros psicométricos adecuados y es una medida útil para futuros estudios sobre la compra compulsiva.

Abstract The objective of this study was to gather evidence of the psychometric properties of the Richmond Compulsive Buying Scale (RCBS) in university students in the Northeast region of Brazil. For this purpose, two studies were conducted. The first study involved 300 university students from the Brazilian Northeast. They were predominantly female (71%), from private universities (67%) and with an average age of 23,5 years old (SD= 6,7). The results indicated a sustainable empirical structure (Kaiser-Meyer-Olkin [KMO] test = 0,82), with psychometric indicators considered adequate for measuring compulsive buying. The results also indicated an unifactorial structure, consisting of six items, which explained 51,85% of the variance, and Cronbach's Alpha of 0,86. The second study aimed at testing the factorial structure found in the first study. A total of 279 university students participated, mostly from public universities (54,1%), male (51,3%) and with an average age of 23,1 years old (EP= 4,74). Through the Confirmatory Factor Analysis, good fit indicators were verified: X2/gl = 2,90; GFI = 0,98; CFI = 0,98; TLI=0,98; RMSEA = 0,08 (IC 90%=04-0,10). It is concluded that the RCBS presented adequate psychometric parameters and is a useful measure for future studies about compulsive buying.

Hollow-fiber liquid-phase microextraction and chiral LC-MS/MS analysis of venlafaxine and its metabolites in plasma.

BACKGROUND: An enantioselective analytical method was developed and validated for determination of venlafaxine and its metabolites O-desmethylvenlafaxine and N-desmethylvenlafaxine in plasma samples. The method employed LC-MS/MS analysis and hollow-fiber liquid-phase microextraction (HF LPME) for sample preparation. RESULTS: After HF LPME optimization the following condition was established: sample volume of 4 ml, sample agitation at 1750 rpm, 20 min of extraction, 0.1 mol/l acetic acid as acceptor phase, 1-octanol as organic phase and donor phase pH adjustment to 10. Under these conditions, the method was linear over the concentration range of 5-500 ng/ml with quantification limits of 5 ng/ml. CONCLUSION: The use of HF LPME for sample preparation provided suitable recoveries, efficient clean-up and low consumption of organic solvent.

Analysis of pharmaceutical pellets: an approach using near-infrared chemical imaging.

Pharmaceutical pellets are spherical or nearly spherical multi-unit dosage forms designed to optimize pharmacokinetics and pharmacodynamics features of drug release. The distribution of the pharmaceutical ingredients in the layers and core is a very important parameter for appropriate drug release, especially for pellets manufactured by the process of layer gain. Physical aspects of the sample are normally evaluated by Scanning Electron Microscopy (SEM), but it is in many cases unsuitable to provide conclusive chemical information about the distribution of the pharmaceutical ingredients in both layers and core. On the other hand, methods based on spectroscopic imaging can be very promising for this purpose. In this work, a Near-Infrared Chemical Imaging (NIR-CI) method was developed and applied to the analysis of diclophenac sodium pellets. Since all the compounds present in the sample were known in advance, Classical Least Squares (CLS) was used for calculations. The results have shown that the method was capable of providing chemical information about the distribution of the active ingredient and excipients in the core and coating layers and therefore can be complementary to SEM for the pharmaceutical development of pellets.