Assessment of Aloe Vera for Qualitative Fit Testing of Particulate Respirators: A Logistic Regression Approach

Fit testing procedure is required for filtering facepiece respirators (FFRs) to ascertain an acceptable fit between the skin and facepiece sealing surface. The present study seeks to compare the efficacy of Aloe vera (A. vera) and commercial BitrexTM as challenge agents of qualitative fit testing of particulate respirators. An herbal solution consisting of A. vera at seven different concentrations was developed. Threshold Screening Tests (TSTs) of A. vera solutions were compared to BitrexTM. To do so, solutions were administered randomly on a total of 62 participants. A placebo was also tested to ensure the taste response being valid. Statistical analysis was performed using R 3.2.5.0 software. There were no statistically significant differences between the A. vera (41.7, 58.3, 75, and 91.7 mg/ml) and BitrexTM threshold tests. Therefore, the minimum concentration of A. vera to develop the threshold solution was considered to be 41.7 mg/ml. When commercial products are expensive and unavailable, a cost-effective technique would be to replace A. vera solution with a commercial product as a challenge agent of qualitative fit testing of respirators

UV determination of epinephrine, uric acid, and acetaminophen in pharmaceutical formulations and some human body fluids using multivariate calibration

In this work, a spectrophotometric methodology was applied in order to determine epinephrine (EP), uric acid (UA), and acetaminophen (AC) in pharmaceutical formulations and spiked human serum, plasma, and urine by using a multivariate approach. Multivariate calibration methods such as partial least squares (PLS) methods and its derivates were used to obtain a model for simultaneous determination of EP, UA and AC with good figures of merit and mixture design was in the range of 1.8 - 35.3, 1.7 - 16.8, and 1.5 - 12.1 µg mL-1. The 2nd derivate PLS showed recoveries of 95.3 - 103.3, 93.3 - 104.0, and 94.0 - 105.5 µg mL-1 for EP, UA, and AC, respectively

Novel amino acids indices based on quantum topological molecular similarity and their application to QSAR study of peptides

A new source of amino acid (AA) indices based on quantum topological molecular similarity (QTMS) descriptors has been proposed for use in QSAR study of peptides. For each bond of the chemical structure of AA, eight electronic properties were calculated using the approaches of bond critical point and theory of atom in molecule. Thus, for each molecule a data matrix of QTMS descriptors (having information from both topology and electronic features) were calculated. Using four different criterion based on principal component analysis of the QTMS data matrices, four different sets of AA indices were generated. The indices were used as the input variables for QSAR study (employing genetic algorithm-partial least squares) of three peptides' data sets, namely, angiotensin-converting enzyme inhibitors, bactericidal peptides and the peptides binding to the HLA-A*0201 molecule. The obtained models had better prediction ability or a comparable one with respect to the previously reported models. In addition, by using the proposed indices and analysis of the variable important in projection, the active site of the peptides which plays a significant role in the biological activity of interest, was identified

Early, Subclinical Hematological Changes Associated with Occupational Exposure to High Levels of Nitrous Oxide

This study was undertaken to determine whether exposure of operating room personnel to inhalation anesthetics, nitrous oxide, isoflurane, and sevoflurane was associated with any hematological changes. This historical cohort study was performed in 2018 at a large public hospital in Shiraz, where 52 operating room personnel and 52 administrative staff were investigated. The blood sample was taken from all individuals for Complete Blood Count. Furthermore, demographic information was collected through questionnaires. Mean atmospheric concentrations of nitrous oxide, isoflurane, and sevoflurane, to which subjects were exposed, were 850.92, 2.40, and 0.18 ppm, respectively. The hematological parameters were within the normal range in both groups. However, the mean values of hemoglobin, hematocrit, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and red blood cell count in the exposed group were significantly lower than the control group. No significant differences were noted between the two groups as far as other hematological factors were concerned. These findings provide circumstantial evidence to further substantiate the notion that occupational exposure to inhalation anesthetics, under the exposure scenario explained in this study, is associated with subtle, subclinical, prepathologic hematological changes. Long-term consequence and ramifications of these effects require further investigation. The range of exposure levels to anesthetic gases in operating rooms

On the Solubility of Ferrocene in Nonaqueous Solvents

The solubility of ferrocene in various organic solvents is important because of its application in chemical process and its role as a standard electrochemical probe in nonaqueous systems. A multilinear quantitative structure property relationship (QSPR) model based on theoretical descriptors and a new linear solvation energy relationship (LSER) model based on empirical scales of solvents are suggested for Ostwald solubility coefficient of ferrocene in 35 organic solvents. The constructed models were validated using different statistical approaches such as internal validation and external test set. In addition to excellent external prediction ability, QSPR and LSER models covered 94 and 92% of cross-validated variance, respectively. The proposed models confirmed the role of polar interactions and basicity of solvents during the solvation of ferrocene in organic phase

Prediction of <i>E</i>^T_N Polarity Scale of Ionic Liquids Using a QSPR Approach

A multiparameter quantitative model was developed to establish a relationship between structural descriptors of a set of 52 ionic liquids and their <i>E</i>^T_N polarity scale. Theoretical descriptors were extracted by Dragon software and the <i>E</i>^T_N model was obtained using multiple linear regression approach. After molecular modeling, four significant descriptors were identified which are related to the <i>E</i>^T_N values of the ionic liquids and demonstrates good fit statistics and accurate predictions. The stability and prediction ability of the <i>E</i>^T_N model was evaluated using various common statistical methods such as cross-validation, external validation, and Y-randomization test. As another indicator of model’s validity, the leverage and standardized residual confirmed the presence of almost all 52 ILs in the applicability domain of the proposed model