New technology of vacuum trioxane crystallization from water solutions

The paper is focused on (i) kinetics of trioxane vacuum crystallization from solution in different apparatus volumes, (ii) vapour–liquid equilibrium and (iii) crystals hardness versus process temperature. It has been found that trioxane is a well-crystallized substance with relatively high effective growth rate and, simultaneously, to some extent, crystals are resistant to attrition. Unfortunately, their elongated shape promotes breaking in the forced magma circulation type crystallizers, but still it is easy to reach well-filtrated product. To meet the objective—a profitable technology for practical application, the studies in pilot scale using industrial solutions were performed. The discussed newly developed vacuum method seems to be a promising alternative for trioxane crystals production instead of a very energy-consuming and low-efficiency cooling crystallization. The additional advantages are simplicity of operation as well as lower capital cost.     

Elastic and thermal parameters of lanthanide-orthophosphate (LnPO4) ceramics from atomistic simulations

We performed extensive and accurate atomistic simulations of elastic and heat transport properties of series of rare-earth orthophosphate ceramics LnPO₄ (Ln = La, …, Lu and Y) in monazite and xenotime structures. The results show clear trends in the elastic moduli along the lanthanide-series, which complement the existing experimental data on these materials. We found that the thermal conductivities of xenotimes are about two times larger than those of monazite, which is in agreement with the experimental measurements and explained by sizes of the primitive cells. Large sets of data allowed assessment of the validity of Slack's model as well as accuracy of molecular dynamics simulations of heat flow for prediction of thermal conductivity. Last, but not least, the separation of the intrinsic and extrinsic contribution to the measured thermal diffusivities allowed for a detailed analysis of the phonon mean free paths in the considered materials.     

Comparison of Metabolite Concentrations in the Left Dorsolateral Prefrontal Cortex,the Left Frontal White Matter,and the Left Hippocampus in Patients in Stable Schizophrenia Treated with Antipsychotics with or without Antidepressants. 1H-NMR Spectroscopy Study

Managing affective, negative, and cognitive symptoms remains the most difficult therapeutic problem in stable phase of schizophrenia. Efforts include administration of antidepressants. Drugs effects on brain metabolic parameters can be evaluated by means of proton nuclear magnetic resonance (¹H-NMR) spectroscopy. We compared spectroscopic parameters in the left prefrontal cortex (DLPFC), the left frontal white matter (WM) and the left hippocampus and assessed the relationship between treatment and the spectroscopic parameters in both groups. We recruited 25 patients diagnosed with schizophrenia (DSM-IV-TR), with dominant negative symptoms and in stable clinical condition, who were treated with antipsychotic and antidepressive medication for minimum of three months. A group of 25 patients with schizophrenia, who were taking antipsychotic drugs but not antidepressants, was matched. We compared metabolic parameters (N-acetylaspartate (NAA), myo-inositol (mI), glutamatergic parameters (Glx), choline (Cho), and creatine (Cr)) between the two groups. All patients were also assessed with the Positive and Negative Syndrome Scale (PANSS) and the Calgary Depression Scale for Schizophrenia (CDSS). In patients receiving antidepressants we observed significantly higher NAA/Cr and NAA/Cho ratios within the DLPFC, as well as significantly higher mI/Cr within the frontal WM. Moreover, we noted significantly lower values of parameters associated with the glutamatergic transmission—Glx/Cr and Glx/Cho in the hippocampus. Doses of antipsychotic drugs in the group treated with antidepressants were also significantly lower in the patients showing similar severity of psychopathology.     

A Proposed Molecular Mechanism of High-Dose Vitamin D3 Supplementation in Prevention and Treatment of Preeclampsia

A randomized prospective clinical study performed on a group of 74 pregnant women (43 presenting with severe preeclampsia) proved that urinary levels of 15-F_2t-isoprostane were significantly higher in preeclamptic patients relative to the control (3.05 vs. 2.00 ng/mg creatinine). Surprisingly enough, plasma levels of 25-hydroxyvitamin D₃ in both study groups were below the clinical reference range with no significant difference between the groups. In vitro study performed on isolated placental mitochondria and placental cell line showed that suicidal self-oxidation of cytochrome P450scc may lead to structural disintegration of heme, potentially contributing to enhancement of oxidative stress phenomena in the course of preeclampsia. As placental cytochrome P450scc pleiotropic activity is implicated in the metabolism of free radical mediated arachidonic acid derivatives as well as multiple Vitamin D₃ hydroxylations and progesterone synthesis, we propose that Vitamin D₃ might act as a competitive inhibitor of placental cytochrome P450scc preventing the production of lipid peroxides or excess progesterone synthesis, both of which may contribute to the etiopathogenesis of preeclampsia. The proposed molecular mechanism is in accord with the preliminary clinical observations on the surprisingly high efficacy of high-dose Vitamin D₃ supplementation in prevention and treatment of preeclampsia.     

Impact of Pre-Ozonation on Mechanical Properties of Selected Genotypes of Cucumber Fruits During the Souring Process

Cucumber souring is a process mediated by a microorganisms present on the surface of cucumber fruits. Sour pickles are fresh cucumbers that have been poured over with a sodium chloride solution and various types of spices. In the present research, pre-ozonated and control cucumber fruits were subjected to the souring processes. It was observed that ozone treatment had no negative impact on the quality of the fruit before the souring process. Moreover, sour pickles after pre-ozonation had better mechanic and sensory properties than the control.     

Numerical Investigation of Sea Salt Aerosol Size Bin Partitioning in Global Transport Models: Implications for Mass Budget and Optical Depth

In this study the importance of sea salt aerosol (SSA) size representation in a global transport model is investigated. For this purpose the Navy Aerosol Analysis and Prediction System (NAAPS) model is employed in a number of SSA simulations. A new dry deposition velocity parameterization is implemented into NAAPS in order to more physically represent deposition processes in the model. SSA size distribution is divided into size bins using two different partition procedures: the previously used iso-log method and the iso-gradient method, which relies on size-dependence of deposition processes. The global SSA simulations are analyzed in terms of the total sea salt mass and the average SSA optical thickness. The results indicate that there is a large dependence of the total mass and average aerosol optical depth on the number of size bins used to represent the aerosol size distribution. The total SSA mass is underestimated by 20% if 2 instead of 15 (reference) size intervals are used. The average aerosol optical depth underestimation is even higher and reaches over 35%. Such large differences can have substantial implications on the accuracy of SSA radiative forcing simulations in climate models. A comparison of the two division procedures shows that the simulations with the iso-gradient intervals are more accurate than the iso-log ones if at least 6 size bins are used. This result indicates that the more physically based division scheme can offer better performance and reduce computational cost of global aerosol transport models.     

Role of two carbon phases in oxygen reduction reaction on the Co–PPy–C catalyst

In spite of a significant progress in their performance in recent years, the heat-treated metal-nitrogen–carbon (M-N–C) non-precious metal catalysts for oxygen reduction reaction (ORR) at the cathode of polymer electrolyte fuel cells (PEFCs) are in need of further improvement to match the activity and, especially, the stability of Pt-based nanoparticle catalysts of oxygen reduction. A better understanding of the role of individual components in M-N–C catalysts is vital for the development of more advanced formulations. In this work, using a cobalt-polypyrrole-carbon catalyst system as an example, we demonstrate that carbon originating from the organic nitrogen precursor (ONP) has different properties than the carbon support. Unlike the carbon originating from polypyrrole, the support carbon helps to enhance ORR performance but negatively impacts the stability. To the best of our knowledge, this may be the first time that the properties of the ONP-derived carbon are being differentiated from the properties of carbon in the carbon support, emphasizing the potential importance of carbon phases in ORR electrocatalysis on heat-treated M-N–C catalysts.