Giant electroviscous effects in a ferroelectric nematic liquid crystal

The electroviscous effect deals with the change in the viscosity of fluids due to the external electric field. Here, we report experimental studies on the electroviscous effects in a ferroelectric nematic liquid crystal. We measure electric field-dependent viscosity under a steady shear rate at different temperatures. In the low field range the increase in viscosity ($\Delta\eta$) is proportional to $E^2$ and the corresponding viscoelectric coefficient ($f$) is two orders of magnitude larger in ferroelectric nematic than the conventional apolar nematic liquid crystals. The apparent viscosity measured under high electric field shows a power-law divergence $\eta\sim(T-T_c)^{-0.7\pm0.05}$, followed by a drastic decrease below the $N-N_{F}$ phase transition. Experimental results within the dynamical scaling approximation demonstrate rapid growth of elongated polar domains under strong electric field which suppresses the $N-N_{F}$ phase transition temperature significantly.Comment: 5 figures, 1 supplementr

Influence of Sleeve Gastrectomy on NASH and Type 2 Diabetes Mellitus

Background. Nonalcoholic fatty liver disease is present in up to 85% of adipose patients and may proceed to nonalcoholic steatohepatitis (NASH). With insulin resistance and obesity being the main risk factors for NASH, the effect of isolated sleeve gastrectomy (ISG) on these parameters was examined. Methods. 236 patients underwent ISG with intraoperative liver biopsy from December 2002 to September 2009. Besides demographic data, pre-operative weight/BMI, HbA1c, AST, ALT, triglycerides, HDL and LDL levels were determined. Results. A significant correlation of NASH with higher HbA1c, AST and ALT and lower levels for HDL was observed (P < .05, <.0001, <.0001, <.01, resp.). Overall BMI decreased from 45.0 ± 6.8 to 29.7 ± 6.5 and 31.6 ± 4.4 kg/m2 at 1 and 3 years. An impaired weight loss was demonstrated for patients with NASH and patients with elevated HbA1c (plateau 28.08 kg/m2 versus 29.79 kg/m2 and 32.30 kg/m2 versus 28.79 kg/m2, resp.). Regarding NASH, a significant improvement of AST, ALT, triglyceride and HDL levels was shown (P < .0001 for all). A resolution of elevated HbA1c was observed in 21 of 23 patients. Summary. NASH patients showed a significant loss of body weight and amelioration of NASH status. ISG can be successfully performed in these patients and should be recommended for this subgroup

Improvement of Type 2 Diabetes Mellitus in Obese and Non-Obese Patients after the Duodenal Switch Operation

Introduction. Type 2 diabetes mellitus (T2DM) is one of the most important obesity-related comorbidities. This study was undertaken to characterise the effect of the biliopancreatic diversion with duodenal switch (BPD-DS) in morbidly obese and nonmorbidly obese diabetic patients. Methods. Outcome of 74 obese diabetic patients after BPD-DS and 16 non-obese diabetic patients after BPD or gastric bypass surgery was evaluated. Insulin usage, HbA1c-levels, and index of HOMA-IR (homeostasis model assessment of insulin resistence) were measured. Results. A substantial fraction of patients is free of insulin and shows an improved insulin sensitivity early after the operation, another fraction gets free of insulin in a 12-month period after the operation and a small fraction of long-term insulin users will not get free of insulin but nevertheless shows an improved metabolic status (less insulin needed, normal HbA1c-levels). Conclusion. BPD-DS leads to an improvement of T2DM in obese and non-obese patients. Nevertheless, more data is needed to clarify indications and mechanisms of action and to adjust our operation techniques to the needs of non-obese diabetic patients

Effect of an electric field on superfluid helium scintillation produced by alpha-particle sources

We report a study of the intensity and time dependence of scintillation produced by weak alpha particle sources in superfluid helium in the presence of an electric field (0 - 45 kV/cm) in the temperature range of 0.2 K to 1.1 K at the saturated vapor pressure. Both the prompt and the delayed components of the scintillation exhibit a reduction in intensity with the application of an electric field. The reduction in the intensity of the prompt component is well approximated by a linear dependence on the electric field strength with a reduction of 15% at 45 kV/cm. When analyzed using the Kramers theory of columnar recombination, this electric field dependence leads to the conclusion that roughly 40% of the scintillation results from species formed from atoms originally promoted to excited states and 60% from excimers created by ionization and subsequent recombination with the charges initially having a cylindrical Gaussian distribution about the alpha track of 60 nm radius. The intensity of the delayed component of the scintillation has a stronger dependence on the electric field strength and on temperature. The implications of these data on the mechanisms affecting scintillation in liquid helium are discussed.Comment: 17 pages, 23 figure

Metabolic surgery in zucker rats influenced miRNA, caveolin-1 expression and lipid metabolism

Aims: A transposition of the long segment of distal ileum in obese Zucker rats improved glucose tolerance 6 months after IT. It was undertaken to compare the gene expression of miRNA-103, -107 and caveolin-1 in the liver of euglycemic groups of IT relative to SHAM operated rats. Main methods: Obese, male Zucker rats underwent either transposition of 50% distal ileum or sham surgery. For determining the gene expression, the Real-Time PCR for caveolin-1 and miRNA-103, -107 was performed. Plasma concentrations of LDL, HDL, TG and total cholesterol were measured with enzymatic colorimetric assays after optimization procedure. Key findings: The Cav-1 expression in liver tissue after ileal transposition was 1.22 times higher compared to the SHAM group (SHAM median 63.58, min 41.3, max 82.4; IT median 77.35, min 60.8, max 95.41, p < 0.001). miRNA-107 expression was significantly downregulated by 0.6-fold in the IT group compared to the SHAM group (SHAM median 507.51, min 236.42, max 721.29; IT median 355.2, min 278.15, max 478.15, p < 0.015. The level of TG was significantly higher after IT surgery (SHAM median 115, min 96, max 143; IT median 153, min 115, max 162, p = 0.001). The total cholesterol plasma levels decreased after IT (SHAM median 178, min 161, max 183; IT median 128, min 103, max 114, p < 0.000001). The LDL plasma level in IT was two-fold lower than in the SHAM (SHAM median 117, min 68, max 151; IT median 58, min 45, max 61, p < 0.000001). Significance: The transposition of 50% of the distal ileum lead to an increase in caveolin-1 and reduction in miR-107 expression compared to those of SHAM group. Endogenous miR-107 is more involved in regulation of the functions of insulin-target liver tissue than miRNA-103. Reduced LDL and cholesterol plasma levels suggest positive effects on lipid metabolism in long-term observations. The present study is the first to show a lack of IT effect regarding triglycerides six months after surgery

Whole Mount in situ Localization of miRNAs and mRNAs During Somatic Embryogenesis in Arabidopsis

Somatic embryogenesis (SE) results from the transition of differentiated plant somatic cells into embryogenic cells that requires the extensive reprogramming of the somatic cell transcriptome. Commonly, the SE-involved genes are identified by analyzing the heterogeneous population of explant cells and thus, it is necessary to validate the expression of the candidate genes in the cells that are competent for embryogenic transition. Here, we optimized and implemented the whole mount in situ hybridization (WISH) method (Bleckmann and Dresselhaus, 2016; Dastidar et al., 2016) in order to analyze the spatiotemporal localization of miRNAs (miR156, miR166, miR390, miR167) and mRNAs such as WOX5 and PHABULOSA-target of miR165/166 during the SE that is induced in Arabidopsis explants. This study presents a detailed step-by-step description of the WISH procedure in which DIG-labeled LNA and RNA probes were used to detect miRNAs and mRNAs, respectively. The usefulness of the WISH in the functional analysis of the SE-involved regulatory pathways is demonstrated and the advantages of this method are highlighted: (i) the ability to analyze intact non-sectioned plant tissue; (ii) the specificity of transcript detection; (iii) the detection of miRNA; and (iv) a semi-quantitative assessment of the RNA abundance

Experimental Modelling of Local Heat Transfer Process for a Gas-liquid System in an Agitated Vessel with the System of A 315 – RT Impellers

The results of the experimental studies of the local heat transfer process for a gas-liquid system in the region of the cylindrical wall of baffled agitated vessel equipped with the system of A 315 (lower) – RT (upper) impellers are presented. Newtonian liquids of different physical properties and air were used as continuous and dispersed phases, respectively. Local heat transfer coefficients were measured using both thermal and electrochemical methods. Distributions of the heat transfer coefficients were described by means of equations (13) – (16) and (17) – (21), separately, for turbulent and transitional ranges of the fluid flow in the agitated vessel. These equations, concerning both coalescing and non-coalescing gas-liquid systems, have no equivalent in the open literature. Moreover, the results for the A 315 – RT impeller system were compared with our previous heat transfer data obtained using CD 6 – RT or RT – RT impeller systems. This work is licensed under a Creative Commons Attribution 4.0 International License

Fusicoccin Counteracts the Toxic Effect of Cadmium on the Growth of Maize Coleoptile Segments

The effects of cadmium (Cd; 0.1–1000 μM) and fusicoccin (FC) on growth, Cd2+ content, and membrane potential (Em) in maize coleoptile segments were studied. In addition, the Em changes and accumulation of Cd and calcium (Ca) in coleoptile segments treated with Cd2+ combined with 1 μM FC or 30 mM tetraethylammonium (TEA) chloride (K+-channel blocker) were also determined. In this study, the effects of Ca2+-channel blockers [lanthanum (La) and verapamil (Ver)] on growth and content of Cd2+ and Ca2+ in coleoptile segments were also investigated. It was found that Cd at high concentrations (100 and 1000 μM) significantly inhibited endogenous growth of coleoptile segments and simultaneously measured proton extrusion. FC combined with Cd2+ counteracted the toxic effect of Cd2+ on endogenous growth and significantly decreased Cd2+ content (not the case for Cd2+ at the highest concentration) in coleoptile segments. Addition of Cd to the control medium caused depolarization of Em, the extent of which was dependent on Cd concentration and time of treatment with Cd2+. Hyperpolarization of Em induced by FC was suppressed in the presence of Cd2+ at 1000 μM but not Cd2+ at 100 μM. It was also found that treatment of maize coleoptile segments with 30 mM TEA chloride caused hyperpolarization of Em and decreased Cd2+ content in coleoptile segments, suggesting that, in the same way as for FC, accumulation of Cd2+ was dependent on plasma membrane (PM) hyperpolarization. Similar to FC, TEA chloride also decreased Ca2+ content in coleoptile segments. La and Ver combined with Cd2+ (100 μM) significantly decreased Cd content in maize coleoptile segments, but only La completely abolished the toxic effect of Cd2+ on endogenous growth and growth in the presence of FC. Taken together, these results suggest that the mechanism by which FC counteracts the toxic effect of Cd2+ (except at 1000 μM Cd2+) on the growth of maize coleoptile segments involves both stimulation of PM H+-ATPase activity by FC as well as Cd2+-permeable, voltage-dependent Ca channels, which are blocked by FC and TEA chloride-induced PM hyperpolarization

Characterizing of a Mid-Latitude Ice-Rich Landing Site on Mars to Enable in Situ Habitability Studies

We suggest an ice-rich landing site at 188.5E 46.16N within Amazonis Planitia as a candidate location to support a Mars lander mission equipped to study past habitability and regions capable of preserving the physical and chemical signs of life and organic matter. Studies of the ice-rich subsurface on Mars are critical for several reasons. The subsurface environment provides protection from radiation to shield organic and biologic compounds from destruction. The ice-rich substrate is also ideal for preserving organic and biologic molecules and provides a source of H2O for biologic activity. Examination of martian ground ice can test several hypotheses such as: 1) whether ground ice supports habitable conditions, 2) that ground ice can preserve and accumulate organic compounds, and 3) that ice contains biomolecules evident of past or present biological activity on Mars. This Amazonis site, located near the successful Viking Lander 2, shows indirect evidence of subsurface ice (ubiquitous defined polygonal ground, gamma ray spectrometer hydrogen signature, and numerical modeling of ice stability) and direct evidence of exposed subsurface ice. This site also provides surface conditions favorable to a safe landing including no boulders, low rock density, minimal rough topography, and few craters

Trichostatin A Triggers an Embryogenic Transition in Arabidopsis Explants via an Auxin-Related Pathway

Auxin is an important regulator of plant ontogenies including embryo development and the exogenous application of this phytohormone has been found to be necessary for the induction of the embryogenic response in plant explants that have been cultured in vitro. However, in the present study, we show that treatment of Arabidopsis explants with trichostatin A (TSA), which is a chemical inhibitor of histone deacetylases, induces somatic embryogenesis (SE) without the exogenous application of auxin. We found that the TSA-treated explants generated somatic embryos that developed efficiently on the adaxial side of the cotyledons, which are the parts of an explant that are involved in auxin-induced SE. A substantial reduction in the activity of histone deacetylase (HDAC) was observed in the TSA-treated explants, thus confirming a histone acetylationrelated mechanism of the TSA-promoted embryogenic response. Unexpectedly, the embryogenic effect of TSA was lower on the auxin-supplemented media and this finding further suggests an auxin-related mechanism of TSA-induced SE. Congruently, we found a significantly increased content of indolic compounds, which is indicative of IAA and an enhanced DR5::GUS signal in the TSA-treated explants. In line with these results, two of the YUCCA genes (YUC1 and YUC10), which are involved in auxin biosynthesis, were found to be distinctly up-regulated during TSA-induced SE and their expression was colocalised with the explant sites that are involved in SE. Beside auxin, ROS were extensively accumulated in response to TSA, thereby indicating that a stress-response is involved in TSA-triggered SE. Relevantly, we showed that the genes encoding the transcription factors (TFs) that have a regulatory function in auxin biosynthesis including LEC1, LEC2, BBM, and stress responses (MYB118) were highly up-regulated in the TSA-treated explants. Collectively, the results provide several pieces of evidence about the similarities between the molecular pathways of SE induction that are triggered by TSA and 2,4-D that involve the activation of the auxin-responsive TF genes that have a regulatory function in auxin biosynthesis and stress responses. The study suggests the involvement of histone acetylation in the auxin-mediated release of the embryogenic program of development in the somatic cells of Arabidopsis