Transcranial Direct Current Stimulation (tDCS) as a Therapeutic Tool for Chronic Insomnia

Background and Objective: Insomnia is the most common sleep problem which is associated with cortical over-excitation. Transcranial direct-current stimulation (tDCS) potentially modifies insomnia-related cortical state. There-fore, we tested the hypothesis that insomnia severity can be modulated by tDCS. Materials and Methods: The current study was conducted with a pretest-posttest design and a control group. A total of 32 women with insomnia were randomly categorized into an intervention group (active stimulation) and a control group (sham stimulation). In the intervention group, tDCS was used with an intensity of 2mA for 20 to 30 minutes during 12 sessions (3 times a week). Anodal stimulation was performed on the left primary motor cortex (M1) and cathodal stimulation was performed on the right dorsal lateral prefrontal cortex (DLPFC). The control group received sham stim-ulation for 20 to 30 minutes during 12 sessions (3 times a week). All participants were evaluated before and after the intervention using the Insomnia Severity Index (ISI) and Positive Affect and Negative Affect Schedule (PANAS). Results: The results of univariate analysis of covariance (ANCOVA) and multivariate analysis of covariance (MANCOVA) showed a significant difference between the tDCS group and the sham group in terms of reduction in the severity of insomnia. We also observed that positive affect increased and negative affect decreased following insomnia treatment (P ≤ 0.005). Conclusion: The results of our study indicated that performing our designed tDCS protocol for treating insomnia can be effective in treating insomnia and improving positive and negative affect

Prenatal Factors Associated with Maternal Cardiometabolic Risk Markers during Pregnancy: The ECLIPSES Study

To examine the associations of sociodemographic, lifestyle, and clinical factors with cardiometabolic risk and each of its components during pregnancy in a pregnant population from Catalonia (Spain). A prospective cohort study of 265 healthy pregnant women (39 ± 5 years) in the first and third-trimesters. Sociodemographic, obstetric, anthropometric, lifestyle and dietary variables were collected, and blood samples were taken. The following cardiometabolic risk markers were evaluated: BMI, blood pressure, glucose, insulin, HOMA-IR, triglycerides, LDL, and HDL-cholesterol. From these, a cluster cardiometabolic risk (CCR)-z score was created by summating all z-scores (except insulin and DBP) computed for each risk factor. Data were analyzed using bivariate analysis and multivariable linear regression. In the multivariable models, the first-trimester CCRs was positively associated with overweight/obesity status (β: 3.54, 95%CI: 2.73, 4.36) but inversely related to the level of education (β: −1.04, 95%CI: −1.94, 0.14) and physical activity (PA) (β: −1.21, 95%CI: −2.24, −0.17). The association between overweight/obesity and CCR (β:1.91, 95%CI: 1.01, 2.82) persisted into the third-trimester, whereas insufficient GWG (β: −1.14, 95%CI: −1.98, −0.30) and higher social class (β: −2.28, 95%CI: −3.42, −1.13) were significantly associated with a lower CCRs. Starting pregnancy with normal weight, higher socioeconomic and educational levels, being a non-smoker, non-consumer of alcohol, and PA were protective factors against cardiovascular risk during pregnancy

Functionalized mesoporous metal oxide spheres as catalysts for efficient conversion of carbohydrates into 5-hydroxymethylfurfural

© 2018 Dr. Seyed Farshad MotevalizadehFossil fuels currently provide more than 90% of global energy needs and feedstocks for the chemical industry. One of the most critical challenges facing mankind is reducing emissions of carbon dioxide. Biomass is a globally accessible resource that could provide an alternative feedstock for synthesizing chemical building blocks. 5-(Hydroxymethyl)furfural (5-HMF) is a commercially useful platform molecule that can be synthesized from biomass. Solid acid catalysts such as metal oxides and modified oxides fill an important role in biomass conversion, due to advantages like carrying both Lewis and Brønsted-acid sites, where the catalytic activity occurs, as well as thermal stability and low cost. The research focus is the preparation, surface modification and characterization of zirconium oxide and binary titanium zirconium oxides spheres as solid-acid catalysts for the conversion of biomass-derived carbohydrates to 5-HMF. In Chapter 2, mesoporous zirconia was functionalized with common di-carboxylic acids and amino acids (i.e. terephthalic acid, 2-amino terephthalic acid, adipic acid, aspartic acid, succinic acid and glutamic acid) to prepare a multifunctional acidic catalyst for conversion of carbohydrates (fructose, glucose, sucrose, cellulose and starch) to 5-HMF. A green and versatile method was utilized to introduce the functional groups on the surface of the zirconia. The final catalyst, which was grafted with terephthalic acid, exhibited acceptable activity towards the dehydration conversion of fructose to 5-HMF with a yield of 42% after 2 h in dimethyl sulfoxide (DMSO) at 150 °C, with negligible loss of activity over five consecutive catalytic recycles. In Chapter 3, mesoporous titanium zirconium oxide spheres were prepared via sol-gel chemistry and templating using a solvothermal and calcination process with varied pore diameters (2.3-10.7 nm), surface areas (76-420 m2 g-1), and surface hydroxyl group densities (4.8-7.0 nm-2). Spheres with high surface area, large pore diameter and high surface hydroxyl density were functionalized with nitrilotri(methylphosphonic acid) via a green and simple method, then used as solid-acid catalysts to produce 5-HMF through the dehydration of carbohydrates. The impact of time, temperature, solvent and amount of catalyst on the yield of 5-HMF was systematically investigated. The recyclability of the catalyst was tested across five consecutive runs. In Chapter 4, sulfated, mesoporous zirconium titanium oxide spheres were synthesized for the catalytic dehydration of carbohydrate to 5-HMF. Five factors affected the sulfate loading: zirconia content, solvothermal temperature, sulfuric acid concentration, duration of the acid treatment, and the post-sulfate grafting calcination temperature. After optimization, the leading catalyst had a maximum sulfate loading of 10.7 wt%, and a total surface acidity of 0.62 mmol g-1. This solid-acid catalyst demonstrated excellent results in the dehydration of fructose to 5-HMF, with a yield of 80% after 1 h in DMSO at 150 °C, and 93% after 6 h. The catalyst was reused in five consecutive cycles with only a 3% loss of activity. Modified zirconia and mesoporous zirconium titanium binary oxide can be considered as promising solid acid catalysts to produce high-value chemicals from biomass feedstocks

A Phenomenological Study of Chromium Impurity Effects on Lattice Microstrains of SnO₂ Nanoparticles Prepared Using Sol–Gel Technique

In this study, the effect of chromium impurities on the crystal structure and lattice microstrains of tin oxide nanoparticles was investigated. Pure SnO2 nanoparticles were synthesized and subjected to calcination at different temperatures. Additionally, various concentrations (5%, 8%, 10% and 15%) of Cr-doped SnO2 nanoparticles were prepared using the sol–gel technique and subsequently calcined at 550 °C. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) techniques were utilized to examine the structure and morphology of the doped nanoparticles. The XRD patterns of tin oxide nanoparticles with different percentages of chromium impurities showed a tetragonal structure without any additional phase. The TEM images of pure SnO2 nanoparticles showed a uniform distribution of size and shape, with relatively smaller sizes compared to Cr-doped nanoparticles. To investigate the peak broadening of Cr-doped SnO2 nanoparticles, the Halder–Wagner method and Williamson–Hall models were employed to examine the effects of crystallite sizes and lattice strain. The results showed that increasing the impurity has a dual effect on nanoparticle sizes. Increasing the chromium impurity up to 8% led to an increase in compressive stress caused by the substitution of Sn ions with Cr ions on the crystal structure of rutile, resulting in an increase in the magnitude of lattice strain. However, when the chromium impurity was increased up to 15%, interstitial doping was preferred over substitutional doping. The compressive stress was subsequently converted to tensile stress, requiring the system to spend some of its energy to overcome the compressive stress, with the remaining energy reflected in the form of tensile stress. Furthermore, Fourier transform infrared (FTIR) spectra were obtained for all of the samples, confirming the XRD analyses

FTIR spectroscopy and multivariate discriminant analysis for classifying bituminous mastics: Exploring aging states and mastic composition

Gefördert im Rahmen des Projekts DEA

Use of multivariate clustering analysis to investigate the physicochemical interactions in bitumen mastics using micromechanical modeling and FTIR spectroscopy

Gefördert im Rahmen des Projekts DEA

Effect of Vacancy Defect Content on the Interdiffusion of Cubic and Hexagonal SiC/Al Interfaces: A Molecular Dynamics Study

The mechanical properties of ceramic–metal nanocomposites are greatly affected by the equivalent properties of the interface of materials. In this study, the effect of vacancy in SiC on the interdiffusion of SiC/Al interfaces is investigated using the molecular dynamics method. The SiC reinforcements exist in the whisker and particulate forms. To this end, cubic and hexagonal SiC lattice polytypes with the Si- and C-terminated interfaces with Al are considered as two samples of metal matrix nanocomposites. The average main and cross-interdiffusion coefficients are determined using a single diffusion couple for each system. The interdiffusion coefficients of the defective SiC/Al are compared with the defect-free SiC/Al system. The effects of temperature, annealing time, and vacancy on the self- and interdiffusion coefficients are investigated. It is found that the interdiffusion of Al in SiC increases with the increase in temperature, annealing time, and vacancy