Canine visceral leishmaniasis diagnosis by UV spectroscopy of blood serum and machine learning algorithms.

Visceral leishmaniasis (VL) is a zoonotic disease caused by the protozoan Leishmania infantum, and dogs are considered the main urban hosts for future disease transmission. The first and most effective control against the spread of disease relies on identifying infected animals, followed by their treatment or sacrifice, to reduce the protozoan reservoirs. Despite the availability of various diagnostic tests for VL in dogs the development of a quick and accurate diagnosis is essential from a public health and ethical point of view. Here we analyze the use of UV-Vis spectroscopy as an alternative diagnostic method for VL diagnosis by using the antigen-antibody interaction in canine blood serum and machine learning algorithms. The main UV spectra in the 220 to 280 nm range exhibit nine electronic absorption bands, but no significative difference could be identified between the positive and negative group spectra. Finally, UV pre-proceed spectra by SNV (standard normal variate) were submitted to principal component analysis followed by Linear SVM algorithm, the prediction model was tested in a leave-one-out cross-validation and external validation test reaching an overall accuracy of 75%.

Novel techniques for drug loading quantification in mesoporous SBA-15 using chemometric-assisted UV and FT-IR data.

Albendazole is a crystalline drug that is poorly soluble in water, thus the dissolution rate in gastrointestinal fluids is limited. Mesoporous materials loaded with poorly water-soluble drugs become an interesting strategy to increase their solubility/dissolution rate as the drug state changes from crystalline to amorphous. In order to determine the drug loading content into mesoporous materials analytical methods such as elemental analysis, UV and HPLC are commonly used. However, elemental analysis and HPLC are destructive and relatively expensive. In addition, UV is time consuming. Moreover, UV and HPLC require the drug release from the mesoporous material before the quantification step. Therefore, the aim of this work was to develop quantifications techniques based on chemometric models combined with UV and FT-IR spectra without needing the drug release from the mesoporous material. Partial least squares regression (PLSR) was used as chemometric regression method. Albendazole content in the SBA-15 powders was first quantified by elemental analysis as reference measurement for multivariate calibration. The excellent drug loading predictions prove that robust calibration models can be obtained from both techniques (i.e., 0.999 and 0.998 adjusted correlation coefficient for UV and FT-IR, respectively). Additionally, the adjusted correlation coefficients determined from the validation models for UV and FT-IR are 0.963 and 0.930, respectively. It is important to highlight that the prediction adjustment of the FT-IR model (root-mean-square error of prediction=2.196%) presented lower error than the UV model (root-mean-square error of prediction=3.553%). Therefore, this development contributes to improve the overall time and cost of drug loading determination into mesoporous materials.

Physicochemical and UV/VIS measurements of UHD solutionsof water, potentized water,and different potencies of organic substance

Conventional science regards the study of UHD (highly homeopathically potentized) solutions as pseudo-science. However, an increasing number of rigorous scientific investigations demonstrate differences in physicochemical and physical characteristics of such solutions. Strictly chemically regarded, they correspond to highly distilled water. Our research team developed a system of physicochemical and UV spectrographic measurements, whereby the differences may be consistently confirmed with high statistical significance.Methods:For measurement of the physicochemical parameters,we usedpH,electrical conductivity,and oxidation-reduction potential (ORP)sensors.For UV/VIS spectroscopymeasurements,we useda Macherey-Nagelspectrophotometer.For UHD research, we used two batches of substances: Russian (R) and Brazilian (B). In R, distilled water (W) was used for dilutions and potencies as follows: potentized water (W cH9), potentized dilution of antibodies to interferon-gamma (Abs IFNγ cH9), the same original substance in the form of a mixture of potencies (Abs IFNγ cH12, cH30, cH50, shortly Abs IFNγ mix). Furthermore, we prepared higher potencies of the substances (supplementary potentiation) in a specially prepared solution and measured their characteristics. In B, the solution was used for further dilutions and potencies as follows: potentized water (W cH1) and Glyphosate potencies (Gly cH6 => cH8, cH30 => cH 32, and cH200 => cH 202).For direct or post-hoc analysis, we used Wilcoxon signed-rank test, two-tailed.Results:UV-VIS spectroscopy (R): measurements of received liquids potentized for further cH1 show statistically significant differences between all substances, except between water W and W cH9 at 260 nm. Significant differences (p-values) were as follows: Abs IFNγ mixvs. W= 0.007; Abs IFNγ mixvs.W cH9=0.008; Abs IFNγ cH9vs. W=0.044; Abs IFNγ cH9vs.W cH9= 0.026; Abs IFNγ mixvs.W cH9= 0.007; W vs.W cH9= 0.506.Physicochemical measurements:R: measurementsdemonstrated statistical difference only in pH (Abs IFNγ mix towards all others). Significant differences (p-values) were as follows: Abs IFNγ mixvs. W=0.022; Abs IFNγ mixvs.W cH9=0.005; Abs IFNγ mixvs.Abs IFNγ cH9=0.025. After supplementarypotentiation, we obtained a more conspicuous picture with many statistical differences in conductivity and ORP, ranging from p= 0.001 to 0.046.A difference between water and potentized water has also been demonstrated.B: the measurements demonstrated statistical differences mainly in pH between Gly cH8 and the rest and between Gly cH202 and W cH1.Significant differences (p-values) were as follows:Gly cH8vs. Gly cH32 =0.027; Gly cH8vs. Gly cH202 = 0.011; Gly cH8vs. W cH1= 0.014; Gly cH202vs. W cH1= 0.034.Conclusion:UV/VIS at wavelength 260 nm Abs IFNγ mix discloses a pattern similar to exclusion zone (EZ)water at 270 nm.By additional potentiation and with physicochemical measurements, we obtained higher statistical differences than in the original dilutions.In contrast, UV/VIS spectroscopy showed more conspicuous results without additional potentiation. However, the very act of succussion becomes very distinct

The Cramer's rule for the parametrization of phenol and its hydroxylated byproducts: UV spectroscopy vs. high performance liquid chromatography.

A linear algebra theorem like Cramer's rule was used for the analysis of a system of equations obtained from UV spectroscopy, and results were compared against those obtained from HPLC analysis. This parametrization allowed to quantify the concentration of the main intermediate products detected along the photodegradation of phenol under UV-Vis irradiation of TiO2. UV spectroscopy data for phenol, hydroquinone, and benzoquinone were analyzed using the Cramer's rule. The overlapping interference of the intermediate products in the UV spectra was corrected. It can be concluded that the Cramer's rule can be used for the parametrization of the UV absorbance data of phenol and its main intermediate products. This methodology permitted to obtain the concentration of phenol and their intermediate products by UV-visible with a high precision in comparison of HPLC. The parametrization showed a correlation coefficient of ca. 0.9775 between the phenol concentration obtained by UV spectroscopy and values obtained from HPLC analysis. In this sense, results can be considered with good precision, and accordingly, it can be concluded that the methodology is reliable, and UV-visible spectroscopy can be selected instead of HPLC in much of the experiments concerning with aqueous-phase reactions.

Chemometric-assisted UV spectrophotometric method for determination of N, N- diethyl-3-methylbenzamide in insect repellents.

In recent years outbreaks of vector-borne diseases have caused great concern to the population, especially those diseases transmitted by mosquitoes. Repellents appear as an affordable alternative for prevention, making it increasingly important to control the quality of these products, since the content of the active ingredients are directly related to the efficiency and the protection time provided by the repellent. This paper proposes an analytical method for determining the DEET (N, N- Diethyl-3-methylbenzamide) content in insect repellents in lotion using UV spectroscopy. For this propose five different strategies of regression were evaluated: (a) Partial Least Squares (PLS) using full-spectrum; (b) interval PLS (iPLS); Multiple Linear Regression (MLR) with variable selection by the (c) Genetic Algorithm (MLR/GA), (d) Successive Projections Algorithm (MLR/SPA) and the (e) Stepwise (MLR/SW). Appropriate predictions were obtained with RMSEP values between 0.88 and 0.93%w w-1. No systematic error was observed and no significant differences were found between the predicted and reference values, according to a paired t-test at 95% confidence level. The results demonstrated the potential of UV spectroscopy associated to multivariate calibration to determine DEET content in repellents as a fast, simple strategy and with a suitable correlation between the values estimated by the model and the reference values.

Avaliação da estabilidade foto-oxidativa dos óleos de canola e de milho em presença de antioxidantes sintéticos / Evaluation of stability photo-oxidative of canola oil and corn oilin the presence of synthetic antioxidants

A estabilidade dos óleos vegetais à oxidação depende do equilíbrio entre a composição e a presença de pró-oxidantes e antioxidantes. O objetivo deste estudo consistiu em avaliar o efeito da presença de antioxidantes sintéticos durante o processo de foto-oxidação dos óleos de canola e milho. As amostras dos óleos de canola e milho em presença e em ausência dos antioxidantes butil-hidroxitolueno (BHA), propil galato (PG) e terc butil-hidroquinona (TBHQ), foram submetidas ao estresse foto-oxidativo. A reação de foto-oxidação seguiu uma cinética de primeira ordem. A constante de velocidade no período de 20 dias de foto-oxidação evidenciou que o antioxidante PG apresentou maior efeito protetor para o óleo de canola e o TBHQ para o óleo de milho. A partir dos dados de UV e RMN de ¹H, no período de 60 dias, constatou-se que os três antioxidantes apresentaram um efeito protetor a foto-oxidação. Os dados de UV evidenciaram aumento de absorção da banda em 232 nm devido à foto-oxidação e formação de dienos conjugados. A redução da intensidade de absorção desta banda na foto-oxidação com o tempo de exposição revelou que a proteção, tanto para o óleo de canola como para o de milho, foi mais efetiva com o antioxidante PG. Os índices de oxidação Roa e fração residual de hidrogênios (H) dialílicos, alílicos e vinílicos também evidenciaram que o antioxidante PG apresentou o melhor desempenho na proteção dos dois tipos de óleo.

The stability of vegetable oils in relation to oxidation depends on the balance between the composition and the presence of antioxidants and pro-oxidants. The objective of this study was to evaluate the effect of the presence of antioxidants in vegetable oils in the protection of photo-oxidation. Samples of canola oil and corn oil in the presence and absence of the antioxidants, butylated hydroxytoluene (BHA), propyl gallate (PG) and tert-butylhydroquinone (TBHQ), were subjected to photo-oxidative stress at room temperature for 60 days. The photo-oxidation reaction followed a first order kinetics. The rate constant for the period of 20 days of photo-oxidation showed that the PG antioxidant showed greater protective effect for canola oil and TBHQ showed a greater protective effect for corn oil. The UV and ¹H NMR data at 60 days showed that the three antioxidants had a protective effect on photo-oxidation. The UV data showed increased absorption at the 232nm band due to photo-oxidation and the formation of conjugated dienes. The reduction in intensity of this absorption band in photo-oxidation with time of exposure revealed that the protection, both for the canola oil and for the corn oil, was more effective with the PG antioxidant. The rates of Roa oxidation and residual fraction of diallyl, allyl and vinyl hydrogens also showed that the PG antioxidant showed the best performance in protecting both oils.

Avaliação da estabilidade foto-oxidativa dos óleos de canola e de milho em presença de antioxidantes sintéticos / Evaluation of stability photo-oxidative of canola oil and corn oilin the presence of synthetic antioxidants

A estabilidade dos óleos vegetais à oxidação depende do equilíbrio entre a composição e a presença de pró-oxidantes e antioxidantes. O objetivo deste estudo consistiu em avaliar o efeito da presença de antioxidantes sintéticos durante o processo de foto-oxidação dos óleos de canola e milho. As amostras dos óleos de canola e milho em presença e em ausência dos antioxidantes butil-hidroxitolueno (BHA), propil galato (PG) e terc butil-hidroquinona (TBHQ), foram submetidas ao estresse foto-oxidativo. A reação de foto-oxidação seguiu uma cinética de primeira ordem. A constante de velocidade no período de 20 dias de foto-oxidação evidenciou que o antioxidante PG apresentou maior efeito protetor para o óleo de canola e o TBHQ para o óleo de milho. A partir dos dados de UV e RMN de ¹H, no período de 60 dias, constatou-se que os três antioxidantes apresentaram um efeito protetor a foto-oxidação. Os dados de UV evidenciaram aumento de absorção da banda em 232 nm devido à foto-oxidação e formação de dienos conjugados. A redução da intensidade de absorção desta banda na foto-oxidação com o tempo de exposição revelou que a proteção, tanto para o óleo de canola como para o de milho, foi mais efetiva com o antioxidante PG. Os índices de oxidação Roa e fração residual de hidrogênios (H) dialílicos, alílicos e vinílicos também evidenciaram que o antioxidante PG apresentou o melhor desempenho na proteção dos dois tipos de óleo.(AU)

The stability of vegetable oils in relation to oxidation depends on the balance between the composition and the presence of antioxidants and pro-oxidants. The objective of this study was to evaluate the effect of the presence of antioxidants in vegetable oils in the protection of photo-oxidation. Samples of canola oil and corn oil in the presence and absence of the antioxidants, butylated hydroxytoluene (BHA), propyl gallate (PG) and tert-butylhydroquinone (TBHQ), were subjected to photo-oxidative stress at room temperature for 60 days. The photo-oxidation reaction followed a first order kinetics. The rate constant for the period of 20 days of photo-oxidation showed that the PG antioxidant showed greater protective effect for canola oil and TBHQ showed a greater protective effect for corn oil. The UV and ¹H NMR data at 60 days showed that the three antioxidants had a protective effect on photo-oxidation. The UV data showed increased absorption at the 232nm band due to photo-oxidation and the formation of conjugated dienes. The reduction in intensity of this absorption band in photo-oxidation with time of exposure revealed that the protection, both for the canola oil and for the corn oil, was more effective with the PG antioxidant. The rates of Roa oxidation and residual fraction of diallyl, allyl and vinyl hydrogens also showed that the PG antioxidant showed the best performance in protecting both oils.(AU)

Spectroscopic behavior of loratadine and desloratadine in different aqueous media conditions studied by means of TD-DFT calculations.

In this study, we explained the influence of the stepwise protonation of two antihistaminic drugs on their experimental absorption spectra. We demonstrated the capability of the TD-CAM-B3LYP method, combined with a polarizable continuum model, to produce good performance for the calculated spectra. The lowest energy transitions and the molecular orbital plots were analyzed in detail. The calculated UV spectra are proposed as potential alternatives to initialize the well-known MCR-ALS algorithm, especially when the spectra of the pure analytes are not available. Moreover, it can be a useful strategy for planning an experimental methodology oriented to multiway analysis when the drug species exhibit acid-base properties.