Spin-coated Tin-doped NiO thin films for third order nonlinear optical applications

A self-made spin-coater was employed to deposit pure and Sn doped nickel oxide thin films on glass substrates. The tin doping impact on the structural, linear and nonlinear optical properties of the spin-coated NiO thin films was studied. The XRD analysis showed that undoped and Sn doped NiO thin films have a cubic structure and are preferentially oriented along the (200) direction. The increase of doping concentration leads to a modification in the values of certain parameters such as the crystallite size and the structural strain as well as affecting the nonlinear optical properties of the doped nickel oxide thin films. The values of the third order nonlinear optical susceptibility, found to be between 2.25 × 10−21 m2/V2 and 3.13 × 10−21 m2/V2, were obtained and analyzed depending on the concentration of the doping

Spin-coated nickel doped cadmium sulfide thin films for third harmonic generation applications

In the current study, different percentages of Nickel (0%, 2%, 4% and 6%) doped CdS thin films have been deposited on glass substrates by the sol-gel spin-coating technique. Before performing the nonlinear optical studies, the structural, morphological and optical properties were examined as a function of Ni doping concentration through the XRD, SEM, AFM and UV–vis spectrometry, respectively. According to the XRD patterns, all films are polycrystalline and the incorporation of Ni does not change qualitatively the crystalline phase of CdS. The Ni doping affects the surface morphology of the CdS thin films which is indicated by scanning electron microscopy and atomic force microscopy images. The band gap was determined via the equation related to the absorption coefficient. It\u27s deduced that the optical band-gap values increased from 2.35 eV to 2.41 eV depending on Ni content. Though, the nonlinear optical properties were determined based on the measurements of the third harmonic generation (THG) using the rotational Maker fringe technique. The results showed that the third order nonlinear optical susceptibilities oscillate between 5.40 × 10−21 m2/V2 for CdS:Ni (2%) and 4.98 × 10−21 m2/V2 for CdS:Ni (6%) while the pure CdS one falls inward, with a value of 5.09 × 10−21 m2/V2

The acute toxicity of nitrobenzenes to Tetrahymena pyriformis: Combining DFT and QSAR studies

A quantitative structure–property relationship study was performed to correlate descriptors representing molecularStructures to the acute toxicity of carbocyclic nitroaromatic compounds to the Tetrahymena Pyriformis, a set of fourty-fiveNitroaromatics derivatives was subjected to the two dimensional quantitative structure activity relationships studies. This work was conducted using the principal component analysis (PCA) method, the multiple linear regression method (MLR), the multiple non-linear regressions (MNLR) and the artificial neural network (ANN). The predicted results of various study compounds afford reliable prediction of -logIGC50 with respect to experimental data. Density functional theory (DFT) calculations have been carried out in order to get insights into the structure, chemical reactivity and property information for the series of study compounds. This study shows that the PCA and ANN have served also to predict activities, but when they compared to the results given by the MLR(R=0.954) and MNLR(R= 0.959), we realized that the predictions fulfilled by these latter were more effective as indicated by the value of cross-validated squared correlation coefficient(RCV (MLR) = 0.924, RCV (MNLR)=0,897) and external validation test(Rtest(MLR) = 0.966, Rtest(MNLR)=0,967 ).Thus, this validated model brings important structural insight to aid the design of toxical compunds to Tetrahymena Pyriformis

Quantitative Structure–Activity Relationship (QSAR) Studies of Some Glutamine Analogues for Possible Anticancer Activity

A Quantitative Structure–Activity Relationship (QSAR) study was performed to predict an anticancer activity in tumor cells of thirty-six 5-N-substituted-2-(substituted benzenesulphonyl) glutamines compounds using the electronic and topologic descriptors computed respectively, with ACD/ChemSketch and Gaussian 03W programs. The structures of all 36 compounds were optimized using the hybrid Density Functional Theory (DFT) at the B3LYP/6-31G(d) level of theory. In both approaches, 30 compounds were assigned as the training set and the rest as the test set. These compounds were analyzed by the Principal Components Analysis (PCA) method, a descendant Multiple Linear Regression (MLR), Multiple Nonlinear Regression (MNLR) analyses and an Artificial Neural Network (ANN). The robustness of the obtained models was assessed by leave-many-out cross-validation, and external validation through a test set.This study shows that the ANN has served marginally better to predict antitumor activity when compared with the results given by predictions made with MLR and MNL

Behavioral and cognitive changes after early postnatal lesions of the rat mediodorsal thalamus

Early insults to the thalamus result in functional and/or structural abnormalities in the cerebral cortex. However, differences in behavioral and cognitive changes after early insult are not well characterized. The present study assessed whether early postnatal damage to mediodorsal nucleus of the thalamus (MD), reciprocally interconnected with the prefrontal cortex, causes behavioral and cognitive alterations in young adult rats. Rat pups at postnatal day 4 received bilateral electrolytic lesion of MD, or aMD Sham lesion or were anesthetized controls; on recovery they were returned to their mothers until weaning. Seven weeks later, all rats were tested with the following behavioral and cognitive paradigms: T-maze test, open field test, actimetry, elevated plus maze test, social interactions test and passive avoidance test. Rats with bilateral MD damage presented with disrupted recognition memory, deficits in shifting response rules, significant hypoactivity, increased anxiety-like behavior, deficits in learning associations as well as decreased locomotor activity, and reduced social interactions compared toMDSham lesion and anesthetized Control rats. The lesion also caused significant decreases in pyramidal cell density in three frontal cortex regions: medial infralimbic cortex, dorsolateral anterior cortex, and cingulate Cg1 cortex. The present findings suggest a functional role for MD in the postnatal maturation of affective behavior. Further some of the behavioral and cognitive alterations observed in these young adult rats after early MD lesion are reminiscent of those present in major psycho-affective disorders, such as schizophrenia in humans

Nanocellulose fibers: A Review of Preparation Methods, Characterization Techniques, and Reinforcement Applications

Cellulose, which occurs naturally in abundance, has the benefit of being the most widely used biomass material on a global scale. It is generated from natural fibers and can be processed to produce various types of nanocellulose fibers, each with its hierarchical configuration. This review summarizes current advances in the production of nanocellulose particles, focusing on the analytical techniques most widely used for their preparation, extraction, and characterization. These techniques include FT-IR, TGA, FESEM, and XRD. The review also demonstrates that research into nanocellulose fibers has progressed exponentially over the last decade (over 400 references). Many manufacturing techniques have been developed to use nanofibers in multiple applications as advanced sustainable materials. The presented data will reinforce the applications of nanocellulose fibers for various purposes

ZnO Nanorods via Spray Deposition of Solutions Containing Zinc Chloride and Thiocarbamide

In this work we present the results on formation of ZnO nanorods prepared by spray of aqueous solutions containing ZnCl2and thiocarbamide (tu) at different molar ratios. It has been observed that addition of thiocarbamide into the spray solution has great impact on the size, shape and phase composition of the ZnO crystals. Obtained layers were characterized by scanning electron microscopy (SEM) equipped with energy selected backscattered electron detection system (ESB), X-ray diffraction (XRD) and photoluminescence spectroscopy (PL). Small addition of thiocarbamide into ZnCl2solution (ZnCl2:tu = 1:0.25) supports development of significantly thinner ZnO nanorods with higher aspect ratio compared to those obtained from ZnCl2solution. Diameter of ZnO rods decreases from 270 to 100 nm and aspect ratio increases from ∼2.5 to 12 spraying ZnCl2and ZnCl2:tu solutions, respectively. According to XRD, well crystallized (002) orientated pure wurtzite ZnO crystals have been formed. However, tiny ‘spot’—like formations of ZnS were detected on the side planes of hexagonal rods prepared from the thiocarbamide containing solutions. Being adsorbed on the side facets of the crystals ZnS inhibits width growth and promotes longitudinalc-axis growth

Dental caries in primary and permanent teeth in children's worldwide, 1995 to 2019: a systematic review and meta-analysis

Background: Early childhood caries (ECC) is a type of dental caries in the teeth of infants and children that is represented as one of the most prevalent dental problems in this period. Various studies have reported different types of prevalence of dental caries in primary and permanent teeth in children worldwide. However, there has been no comprehensive study to summarize the results of these studies in general, so this study aimed to determine the prevalence of dental caries in primary and permanent teeth in children in different continents of the world during a systematic review and meta-analysis. Methods: In this review study, articles were extracted by searching in the national and international databases of SID, MagIran, IranMedex, IranDoc, Cochrane, Embase, ScienceDirect, Scopus, PubMed, and Web of Science (ISI) between 1995 and December 2019. Random effects model was used for analysis and heterogeneity of studies was evaluated by using the I2 index. Data were analyzed by using the Comprehensive Meta-Analysis (Version 2) software. Findings: In this study, a total of 164 articles (81 articles on the prevalence of dental caries in primary teeth and 83 articles on the prevalence of dental caries in permanent teeth) were entered the meta-analysis. The prevalence of dental caries in primary teeth in children in the world with a sample size of 80,405 was 46.2% (95% CI: 41.6–50.8%), and the prevalence of dental caries in permanent teeth in children in the world with a sample size of 1,454,871 was 53.8% (95% CI: 50–57.5%). Regarding the heterogeneity on the basis of meta-regression analysis, there was a significant difference in the prevalence of dental caries in primary and permanent teeth in children in different continents of the world. With increasing the sample size and the year of study, dental caries in primary teeth increased and in permanent teeth decreased. Conclusion: The results of this study showed that the prevalence of primary and permanent dental caries in children in the world was found to be high. Therefore, appropriate strategies should be implemented to improve the aforementioned situation and to troubleshoot and monitor at all levels by providing feedback to hospitals