Positioning of an isothermal heat storage layer in a building wall exposed to the external environment

The paper presents an idea for the enhancement of a building's thermal insulation component by adding into the structure a thin layer of a phase-change material (PCM). The proposed solution can be dedicated, for example, to an external partition of lightweight construction. The capacity for latent heat storage allowed it to stabilize the temperature inside the insulation layer in a daily cycle and to minimize the temperature difference between the internal and external surfaces. In this paper, different positions of a PCM layer in the thermal insulation of an external wall were analysed. The main goal of this work was to find the best position of the PCM layer, taking into account the indoor temperature and the meteorological conditions. The authors propose two parameters: the amount of stored energy and the dynamism of the charging/discharging processes. Taking into account large temperature fluctuations on the external surface during summer and winter, it was concluded that, for this specific case, the most appropriate solution would be an external position of the PCM with a melting temperature of 20°C.     

A Roadmap for Controlled and Efficient n‐Type Doping of Self‐Assisted GaAs Nanowires Grown by Molecular Beam Epitaxy

N‐type doping of GaAs nanowires has proven to be difficult because the amphoteric character of silicon impurities is enhanced by the nanowire growth mechanism and growth conditions. The controllable growth of n‐type GaAs nanowires with carrier density as high as 10²⁰ electron cm^?3 by self‐assisted molecular beam epitaxy using Te donors is demonstrated here. Carrier density and electron mobility of highly doped nanowires are extracted through a combination of transport measurement and Kelvin probe force microscopy analysis in single‐wire field‐effect devices. Low‐temperature photoluminescence is used to characterize the Te‐doped nanowires over several orders of magnitude of the impurity concentration. The combined use of those techniques allows the precise definition of the growth conditions required for effective Te incorporation.     

Instrumentation for medium-throughput two-dimensional capillary electrophoresis with laser-induced fluorescence detection

In two-dimensional capillary electrophoresis, a sample undergoes separation in the first dimension capillary by sieving electrophoresis. Fractions are periodically transferred across an interface into a second dimension capillary, where components are further resolved by micellar electrokinetic capillary electrophoresis. Previous instruments employed one pair of capillaries to analyze a single sample. We now report a multiplexed system that allows separation of five samples in parallel. Samples are injected into five first-dimension capillaries, fractions are transferred across an interface to 5 second-dimension capillaries, and analyte is detected by laser-induced fluorescence in a five-capillary sheath-flow cuvette. The instrument produces detection limits of 940 +/- 350 yoctomoles for 3-(2-furoyl)quinoline-2-carboxaldehyde labeled trypsin inhibitor in one-dimensional separation; detection limits degrade by a factor of 3.8 for two-dimensional separations. Two-dimensional capillary electrophoresis expression fingerprints were obtained from homogenates prepared from a lung cancer (A549) cell line, on the basis of capillary sieving electrophoresis (CSE) and micellar electrophoresis capillary chromatography (MECC). An average of 131 spots is resolved with signal-to-noise greater than 10. A Gaussian surface was fit to a set of 20 spots in each electropherogram. The mean spot width, expressed as standard deviation of the Gaussian function, was 2.3 +/- 0.7 transfers in the CSE dimension and 0.46 +/- 0.25 s in the MECC dimension. The standard deviation in spot position was 1.8 +/- 1.2 transfers in the CSE dimension and 0.88 +/- 0.55 s in the MECC dimension. Spot capacity was 300.     

Shotgun analysis of integral membrane proteins facilitated by elevated temperature

The beneficial effects on peak selectivity and resolution of conducting liquid chromatography (LC) at elevated temperature (e.g., 30-80 degrees C) are generally well-known; however, its importance for peptide recovery is not nearly as well recognized. This report demonstrates that microLC analysis of membrane proteomic samples significantly benefits from the application of heat. Enriched membrane and membrane-embedded peptides (the latter obtained by membrane shaving) were analyzed by microLC-tandem mass spectrometry (MS/MS) from 20 to 60 degrees C using a standard reversed-phase material. Maximal protein and hydrophobic peptide recovery was obtained at 60 degrees C. The membrane-shaving method employed, a recently optimized version of the high pH/proteinase K protocol, provided significant integral membrane protein enrichment: 98% of identified proteins were predicted to have at least one transmembrane domain (87% to have at least three), and 68% of peptides were predicted to contain transmembrane segments. Analysis of this highly enriched sample at elevated temperature increased protein identifications by 400%, and peptide identifications by 500%, as compared to room-temperature separation. Given that most microLC-MS/MS analyses are currently conducted at room temperature, the findings described herein should be of considerable value for improving the comprehensive study of integral membrane proteins.     

Fiber-optic microsensors for simultaneous sensing of oxygen and pH, and of oxygen and temperature

Fiber-optic microsensors with a tip diameter of approximately 140 microm have been developed that enable simultaneous measurement of dissolved oxygen (DO) and pH, and of DO and temperature (T), respectively. The tip of the optical fiber was covered with sensor compositions based on luminescent microbeads that respond to the respective parameters by a change in the decay time, intensity of their luminescence, or both. The use of microbeads enables the ratio of the signals to be easily varied, reduces the risk of fluorescence energy transfer between indicator dyes, and reduces the adverse effect of singlet oxygen that is produced in the oxygen-sensitive beads. The sensor chemistry for DO/pH was modified.     

Spontaneous emission from the C3 radical in carbon plasma

Spontaneous emission measurements are discussed for the Swings transitions of the C(3) radical in laser-generated graphite plasma, and the spectroscopy of the C(3) radical in carbon vapor and plasma is summarized. A review is given of some theoretical calculations and emission spectroscopic investigations are presented. Time-averaged, laser-induced optical breakdown spectra are reported from Nd:YAG laser generated graphite microplasma. In 200-300 Torr of argon and helium, and depending on the specific experimental configuration, a weak emission continuum is observed centered at 400 nm when using a laser fluence of typically 1 J/cm(2). Such continua were not detected in our previous experiments using focused laser radiation. The possibilities for the origin of this continuum are considered.     

Electrokinetic removal of 2,6-dichlorophenol and diuron from kaolinite and humic acid-clay system

This paper presents the results of a study on the electrokinetic treatment of kaolinite and humic acid kaolinite complexes spiked with 2,6-dichlorophenol or 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron). In particular, the attention was paid to the interaction between solid surface and dissolved organics: the effects of contaminant sorption as well as the physicochemical reactions on the efficiency of electrokinetic remediation were investigated. Using a 3V/cm voltage gradient, approximately 90% of diuron was removed from kaolinite after one water pore volume was collected in the cathode reservoir, but much lower efficiency was obtained in the electrokinetic removal of this compound from humic acid-coated kaolinite. The results also showed that partial degradation of the contaminant occurred during electrokinetic treatment of kaolinite clay spiked with 2,6-dichlorophenol: the contamination in the clay could be remediated by the combination of electrokinetic extraction and electrochemical reactions.     

Functional studies of synthetic gramicidin hybrid ion channels in CHO cells

The function of a gramicidin hybrid ion channel in living Chinese hamster ovary (CHO) cells was investigated by the patch clamp method. The synthetic ion channel 1 consists of two cyclohexyl ether amino acids that link two mini-gramicidin strands. With 1 at a concentration of 1.0 microM, an increase in the whole-cell membrane conductance was observed after 1.37 min. The conductance showed larger currents when Cs(+) was used as charge carrier than when Na(+) and K(+) were used. In single-channel recordings with Cs(+) as charge carrier, the substance showed comparable single-channel amplitudes in the membrane of living cells and artificial black lipid bilayers. In addition to functioning as a cation channel, compound 1 appeared to be a water channel. Exposure of the CHO cells to an extracellular hypoosmotic solution did not substantially change the cell volume. Extracellular hypoosmotic conditions in the presence of 1 increased the cell size to 146.5 % that of the control. Thus, the synthetic hybrid channel 1 can function as a cation channel with some Cs(+) specificity, and as a water channel in CHO cells.     

Benzo[d]isothiazol-3-yl-benzamidines: a class of protective agents on culture of human cartilage and chondrocytes stimulated by IL-1beta

New derivatives of N-benzo[d]isothiazol-3-yl-benzamidine 6 a were synthesized as nonacidic anti-inflammatory/antidegenerative agents. We investigated the influence of the amidines 6 a-j on the production of NO, PGE(2), MMP-3, COX-2, ROS, and GAGs, key molecules involved in cartilage destruction in osteoarthritic diseases. The antidegenerative properties of the novel designed derivatives 6 b-j were improved with respect to N-benzo[d]isothiazol-3-yl-benzamidine 6 a. All of the compounds 6 a-j promoted the reduction of most of the IL-1beta-induced harmful effects. Derivatives 6 d, 6 h, and 6 j were the most potent of all the tested compounds, particularly in the human chondrocyte culture model.