Biosynthesis of growth hormone-releasing factor by fetal rat cerebrocortical and hypothalamic cells

The biosynthesis of growth hormone-releasing factor (GRF) by cerebrocortical tissue is controversial. Although several reports have indicated its presence in certain rat cortical areas and in cultured rat hypothalamic cells, no data exist demonstrating its biosynthesis in these areas. In this study, we have investigated the capacity of fetal rat cerebrocortical and hypothalamic cells in culture for synthesizing GRF. Fetal cerebrocortical and hypothalamic cells were exposed to [3H]Arg for 48 h. Medium and cell extracts were processed and [3H]Arg-IR-rGRF was isolated by affinity chromatography and characterized by HPLC. Intracellular [3H]Arg-IR-rGRF from both hypothalamic and cerebrocortical cells exhibited four major peaks, one of them coeluting with synthetic rGRF. In cerebrocortical cultures, newly synthesized and released [3H]Arg-IR-rGRF showed a similar pattern to the cell content. However, in media from hypothalamic cells, higher hydrophobicity molecular forms were absent. The data demonstrated that fetal cerebrocortical and hypothalamic cells in primary culture synthesize GRF with similar posttranslational processing, but with different molecular patterns of secretion.     

Melting behavior,crystallization kinetics and morphology of random copolyesters of poly(2‐hydroxyethoxybenzoate) with ε‐caprolactone

The melting behavior after isothermal crystallization and the crystallization kinetics of random poly(2‐hydroxyethoxybenzoate/ε‐caprolactone) copolymers rich in 2hydroxyethoxybenzoate units were investigated by means of differential scanning calorimetry and hot‐stage optical microscopy. The observed multiple endotherms, which are commonly displayed by polyesters, were found to be influenced both by crystallization temperature and composition. By applying the Hoffman‐Weeks method to the melting temperatures of isothermally crystallized samples, the equilibrium melting temperatures of the copolymers were obtained. Furthermore, isothemal crystallization kinetics was analyzed according to the Avrami treatment. Values of the exponent n close to 3 were obtained, independently of crystallization temperature and composition, in agreement with a crystallization process originating from predeterminated nuclei and characterized by three‐dimensional spherulitic growth. Space‐filling banded spherulites were observed by hot‐stage optical polarizing microscopy at all the crystallization temperatures explored, the band spacing being affected by both crystallization temperature and composition. As expected, the introduction of ε‐caprolactone comonomeric units in the polymer chain of PHEBA was found to decrease its crystallization rate.     

DRYING OF BIOLOGICAL PRODUCTS WITH SIGNIFICANT VOLUME VARIATION. EXPERIMENTAL AND MODELING RESULTS FOR POTATO DRYING.

This work is devoted to the experimental investigation and theoretical modeling of biological products with high initial moisture content which implies significant volume contraction. Firstly, experimental equipment which was designed to continuously determine variations in the global moisture content and in the temperature of the sample is introduced. Furthermore, the equipment is controlled by a PC which records experimental information in real time. In particular, measurement of the radial and temporal distributions of moisture content and temperature during the drying process of the homogeneous porous media potato are given. The mean moisture content and temperature curves are also given.     

Assessment of Relationships between Sensory and Instrumental Quality of Controlled-atmosphere-stored 'Fuji' Apples by Multivariate Analysis

ABSTRACT: Physicochemical parameters, sensory attributes, and total aroma emission of ‘Fuji’ apples (Malus×domestica Borkh.) were studied in relation to storage conditions, storage duration, and shelf life period. Commercially ripe fruit were analyzed after 3, 5, and 7 mo of cold storage in normal atmosphere (AIR) (210 L/m³ O₂+ 0.3 L/m³ CO₂) or under 3 different controlled atmosphere (CA) treatments (10 L/m³ O₂+ 10 L/m³ CO₂, 20 L/m³ O₂+ 20 L/m³ CO₂, or 10 L/m³ O₂+ 30 L/m³ CO₂), after which apples were kept at 20 °C for 1, 5, and 10 d. Data were subjected to partial least square regression (PLSR) analysis. Physicochemical parameters were well preserved throughout storage, especially in CA‐stored apples; however, these apples showed lower total aroma emission. Sensory acceptability was also higher for CA‐stored fruit after 7 mo of storage, whereas no significant differences were found for shorter storage periods. Accordingly, greater scores in sensory firmness, sensory flavor, sensory acidity, and appearance were observed for fruit stored in 10 L/m³ O₂+ 10 L/m³ CO₂ after long storage. Two PLSR models were established, 1 for relating physicochemical parameters to overall acceptability, and another for assessing the correlation between sensory acidity and instrumentally measured titratable acidity. The 1st PLSR model indicated that soluble solids concentration, titratable acidity, flesh firmness, and background color of the shaded side have a positive influence on acceptability. The 2nd model indicated that sensory acidity also showed an excellent correlation to instrumentally measured titratable acidity.     

Anticancer Ruthenium(III) Complex KP1019 Interferes with ATP‐Dependent Ca2+ Translocation by Sarco‐Endoplasmic Reticulum Ca2+‐ATPase (SERCA)

Sarco‐endoplasmic reticulum Ca²⁺‐ATPase (SERCA), a P‐type ATPase that sustains Ca²⁺ transport and plays a major role in intracellular Ca²⁺ homeostasis, represents a therapeutic target for cancer therapy. Here, we investigated whether ruthenium‐based anticancer drugs, namely KP1019 (indazolium [trans‐tetrachlorobis(1H‐indazole)ruthenate(III)]), NAMI‐A (imidazolium [trans‐tetrachloro(1H‐imidazole)(S‐dimethylsulfoxide)ruthenate(III)]) and RAPTA‐C ([Ru(η⁶‐p‐cymene)dichloro(1,3,5‐triaza‐7‐phosphaadamantane)]), and cisplatin (cis‐diammineplatinum(II) dichloride) might act as inhibitors of SERCA. Charge displacement by SERCA adsorbed on a solid‐supported membrane was measured after ATP or Ca²⁺ concentration jumps. Our results show that KP1019, in contrast to the other metal compounds, is able to interfere with ATP‐dependent translocation of Ca²⁺ ions. An IC₅₀ value of 1 μM was determined for inhibition of calcium translocation by KP1019. Conversely, it appears that KP1019 does not significantly affect Ca²⁺ binding to the ATPase from the cytoplasmic side. Inhibition of SERCA at pharmacologically relevant concentrations may represent a crucial aspect in the overall pharmacological and toxicological profile of KP1019.     

Influence of rotor structural dynamics representations on the electrical transient performance of FSIG and DFIG wind turbines

An assessment of the impact that the representation of rotor structural dynamics has on the electrical transient performance of fixed‐speed induction generators (FSIGs) and doubly fed induction generators (DFIGs) wind turbines is presented. A three‐mass model that takes into account not only the shaft flexibility but also the blade flexibility in the structural dynamics is developed and used to derive an effective two‐mass model of the drive train dynamics, which represents the dominant natural frequency of vibration of the rotor structure. For the purposes of this investigation, the dynamic performance of both FSIG and DFIG wind turbines is evaluated during electrical transients such as a three‐phase fault in the network. The studies are conducted in the software code Bladed, where a detailed representation of the structural dynamics is used to derive the three‐mass model and the effective two‐mass model. Simulation results which illustrate how these representations of the rotor dynamics affect the response of the wind turbine during the fault are presented and discussed. Copyright © 2007 John Wiley & Sons, Ltd.     

Synthesis of cobalt–silicon oxide thin films

Silicon–cobalt oxide thin films were prepared by the dipping sol–gel process. Samples with different number of dipping–annealing cycles were prepared. Some data regarding the precursor sol are given from small angle X-ray scattering characterization. Composition, structure, surface morphology and optical properties are obtained from X-ray diffraction, reflectance, transmittance, FTIR, scanning electron microscopy and EDX spectroscopy measurements. The silicon–cobalt oxide thin films prepared in this work are mostly amorphous. They have a high absorption coefficient in the visible and infrared regions. A refractive index from 2.15 to 1.79 (at 1200 nm wavelength), and a band gap between 3.73 and 3.68 eV with increasing film thickness were measured in the films. Sol–gel prepared Si–Co oxide thin films could be well suited for use in photothermal solar collectors.     

Energy requirements for a swimming pool through a water-atmosphere energy balance

The methodology displayed here is to calculate the energy requirements for heating a swimming pool to a desired temperature. This methodology consists of an energy balance between water-atmosphere as is used in the temperature evaluation of cooling ponds in power plants. Different mathematical expressions are given to calculate such a balance. It is necessary to know the month of the year, the ambient temperature, relative humidity, wind velocity, and solar radiation. With these parameters it is possible to know the natural temperature of the water, natural evaporation, energy needed to reach a determined swimming pool temperature and the evaporation of the heated pool.     

A New Approach to Quantify Na-Fluorescein (Uranine) in Acid Mine Waters

Sodium fluorescein (uranine) is one of the most popular fluorescent dyes for tracer experiments due to its chemical properties, low detection limits and low costs. As a limiting factor, it is generally assumed that Na-fluorescein cannot be properly detected under acid conditions because of weak fluorescence intensities at the standard excitation wavelength (490 nm). This laboratory study introduces a method to quantify Na-fluorescein in low pH waters without having to raise pH to alkaline conditions, which spares the time- and cost-intensive filtration of hydroxide precipitates prior to analysis. It was applied for recovery tests in water samples from five mining sites in Germany. These were buffered to pH 1.5 where Na-fluorescein shows a second fluorescence intensity maximum at an excitation wavelength of 438 nm. The method had satisfying recovery rates although, as expected, a higher detection limit compared to standard wavelength and pH. High Fe contents in the waters are a limiting factor—the impact of increasing Fe concentrations at a constant dye spike was evaluated and yielded a distinct negative trend between Fe and detected Na-fluorescein, probably due to Fe-fluorescein complexation. However, good recovery can be expected in mine waters with up to ≈100 mg L⁻¹ Fe. The method of standard addition offers a potential calculative solution for higher Fe concentrations, resulting in significantly better Na-fluorescein recovery rates, compared to direct measurements. The method introduced here represents a promising approach for improving Na-fluorescein applicability in acid environments.