Measurement and correlation of high pressure phase behavior of carbon dioxide + water system

A visual and variable volume view cell analyzer was installed and the phase behaviors of the carbon dioxide + water system were measured in the temperature and pressure ranges from 313.2 K to 343.2 K and from 4.33 MPa to 18.34 MPa, respectively. The measured data were correlated with the MF-NLF-HB equation of state to consider the effects of the hydrogen bonding of the saturated liquid and vapor mixture. The calculated data agree well with the measured data within an absolute average error deviation of 5%. The fraction of hydrogen bonding could be calculated by the MF-NLF-HB EOS for the carbon dioxide + water system with the obtained VLE data. The calculated hydrogen bonding fraction of the saturated liquid phase of the mixture decreased with increasing pressure in the isothermal calculations. The hydrogen bond strength was affected by the concentration of carbon dioxide and solubility of carbon dioxide was affected by pressure. The calculated hydrogen bonding fraction of the saturated vapor phase of the mixture had a minimum value near 10 MPa for the three isothermal calculations.     

The ParTriCluster Algorithm for Gene Expression Analysis

Analyzing gene expression patterns is becoming a highly relevant task in the Bioinformatics area. This analysis makes it possible to determine the behavior patterns of genes under various conditions, a fundamental information for treating diseases, among other applications. A recent advance in this area is the Tricluster algorithm, which is the first algorithm capable of determining 3D clusters (genes × samples × timestamps), that is, groups of genes that behave similarly across samples and timestamps. However, even though biological experiments collect an increasing amount of data to be analyzed and correlated, the triclustering problem remains a bottleneck due to its NP-Completeness, so its parallelization seems to be an essential step towards obtaining feasible solutions. In this work we propose and evaluate the implementation of a parallel version of the Tricluster algorithm using the filter-labeled-stream paradigm supported by the Anthill parallel programming environment. The results show that our parallelization scales well with the data size, being able to handle severe load imbalances that are inherent to the problem. Further more, the parallelization strategy is applicable to any depth-first searches.     

Synthesis of diketopyrrolopyrrole (DPP)-based small molecule donors containing thiophene or furan for photovoltaic applications

Two π-conjugated small molecules based on diketopyrrolopyrrole (DPP), DPP4T and DPP2F2T, were synthesized using the Suzuki coupling reaction. DPP4T and DPP2F2T contained furan and thiophene, respectively, next to a DPP core. Organic photovoltaic cells (OPVs) were fabricated using two DPP-based oligothiophenes as donors. DPP4T showed higher power conversion efficiency (PCE) (1.44%) than DPP2F2T (0.85%). The short-circuit current (J_SC) of DPP4T (4.38 mA cm⁻²) was nearly twice that of DPP2F2T (2.49 mA cm⁻²). The improved photovoltaic properties of DPP4T could be explained by the optical properties and the film morphology.     

Development and validation of a dissolution test for lodenafil carbonate based on in vivo data

Introduction: Lodenafil carbonate is a phosphodiesterase type 5 inhibitor used for the treatment of erectile dysfunction. Currently, there is no dissolution test reported for lodenafil carbonate and this drug is not listed in any pharmacopoeia.

Objective: The present study focused on the development and validation of a dissolution test for lodenafil carbonate tablets, using a simulated absorption profile based on in vivo data.

Methods: The appropriate conditions were determined after testing sink conditions. Different conditions as medium, surfactant concentration and rotation speed were evaluated. The percentage of dose absorbed was calculated by deconvolution, using the Wagner–Nelson method.

Results: According to the obtained results, the use of 0.1?M HCl?+?1.5% SLS (900?mL, at 37?+?0.5?°C) as the dissolution medium, paddles at 25?rpm were considered adequate. The samples were quantified by UV spectroscopy at 295?nm and the validation was performed according to international guidelines. The method showed specificity, linearity, accuracy and precision, within the acceptable range. Kinetics of drug release was better described by the first-order model.

Conclusion: The proposed dissolution test can be used for the routine quality control of lodenafil carbonate in tablets.     

New Filling Technique and Performance Evaluations of the Cr3C2?C Peritectic Fixed Point

The Cr₃C₂?C peritectic fixed point was investigated to test its capability to serve as a practical high-temperature fixed point. An improved filling technique where C/C sheet works as a wick and graphite paper as a hopper was applied successfully, and the long-term stability of the peritectic cell was evaluated by means of radiation thermometry. The repeatability of the melting point in one day was 7 mK with a melting range of approximately 100 mK. The cell was aged for 7 days, and the evaluated 56 melting temperatures during this period all fall within 90 mK, with a standard deviation of 19 mK. X-ray transmission photos showed that the ingot was filled uniformly in the crucible. After the evaluation of long-term stability, no clear degradation of the ingot shape and no leakage of molten metal were observed. From these results, it can be concluded that the Cr₃C₂?C peritectic cell has good stability and robustness, and the new filling technique was established. The impurity effect on the Cr₃C₂?C peritectic cell was also investigated by adding tungsten powder to another cell as the impurity component. After the observation of melting and freezing plateaux, the cell was cut in half to analyze the microstructure by means of electron probe microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS). The high concentration of impurity was observed in the area of the chromium-rich domain (eutectic mixture of Cr₇C₃ and Cr₃C₂), which suggests that impurities were rejected from the Cr₃C₂ peritectic phase during the peritectic freezing and were accumulated in the Cr₇C₃?Cr₃C₂ eutectic phase. This explains why the impurity effect is more severe for the Cr₇C₃?Cr₃C₂ eutectic point than for the Cr₃C₂?C peritectic point.     

Utilizing Accessible Heat Enhancing Cooling Effect with Three Bed Solar Adsorption Chiller

ABSTRACT

Conventional solar heat-driven single stage two bed chillers demand a large area for installation of solar thermal collector to activate the chiller, but in a highly populated tropical country open spaces is insufficient. In the intention to utilize accessible solar energy with better performance, a mathematical investigation is carried out with a three bed adsorption cooling unit working with silica gel-water pair. The studied chiller is powered by direct solar heat collected by a series of compound parabolic concentrator solar thermal collectors without any heat or mass recovery. The working principal of the chiller is, in principle, the same as the conventional two-bed adsorption chiller. However, instead of two half cycles, there are three one third cycles in the proposed chiller in which at every cycle the former desorber is kept in the precooling mode and as an adsorber for the next two one third cycles, respectively. As desorption kinetic is faster than the adsorption kinetics, this longer precooling mode helps the silica gel granules to adsorb more water molecules and increase evaporation rate. Hence, a better cooling effect of at least 1°C can be observed, increases chiller working hour after sunset for almost a further one hour.     

Fiber optic hot-wire flowmeter based on a metallic coated hybrid long period grating/fiber Bragg grating structure

In this work an all-optical hot-wire flowmeter based on a silver coated fiber combining a long period grating and a fiber Bragg grating (FBG) structure is proposed. Light from a pump laser at 1480 nm propagating down the fiber is coupled by the long period grating into the fiber cladding and is absorbed by the silver coating deposited on the fiber surface over the Bragg grating structure. This absorption acts like a hot wire raising the fiber temperature locally, which is effectively detected by the FBG resonance shift. The temperature increase depends on the flow speed of the surrounding air, which has the effect of cooling the fiber. It is demonstrated that the Bragg wavelength shift can be related to the flow speed. A flow speed resolution of 0.08 m/s is achieved using this new configuration.     

Expression of smooth-muscle actin in cultured cells from human plasmacytoid myoepithelioma

BACKGROUND: Endoscopic sclerotherapy (ST), widely used as treatment of bleeding esophageal varices, might cause motility disturbances of the esophagus as well as mucosal damage. We performed this study to evaluate the long-term effects of repeated sclerotherapy on esophageal motility and mucosa. METHODS: Ten patients with liver cirrhosis and bleeding esophageal varices treated with repeated ST were evaluated after the last ST, median 52 months, by esophageal manometry and gastroscopy where forceps biopsies were taken. RESULTS: We found a significant difference in the distal esophageal sphincter intraabdominal length. The distal esophageal sphincter pressure was somewhat lower in the ST group although the difference did not reach statistical significance. There was infiltration of neutrophil leukocytes in biopsies from four patients and normal findings in the rest. CONCLUSIONS: Long-term follow-up evaluation showed statistically longer distal esophageal intraabdominal length in the ST group. No mucosal alterations were found at the histopathological investigation.