Crystal Structures,Thermogravimetric and Magnetic Properties of Four Organodiamine Templated Vanadium Oxide Frameworks: Influences of Diaminoalkane Templates

Absract A series of four diaminoalkane templated vanadium oxide polymeric frameworks, [V₂^IVO₈V₂^VO₂](C₂H₁₀N₂), [V₂^IVO₈V₂^VO₂](C₃H₁₂N₂), [V₄^IVO₁₀V₂^VO₄](C₄H₁₄N₂) and [V₄^IVO₁₀V₂^VO₄](C₅H₁₆N₂), have been successfully prepared under hydrothermal conditions. The crystal structures are fully characterized revealing layered structures composed of common inorganic building units, namely {V^IVO₅} square pyramids and {V^VO₄} tetrahedra. The layer registries are different depending on the molecular structure of the diaminoalkanes, and can be accounted for by the organic-inorganic interface interactions. The analysis of hydrogen bonds indicates their important role in directing two- and three-dimensional structural architectures. The influences of different diaminoalkanes are also apparent in both thermogravimetric and complex magnetic behaviors, and are discussed in details.     

Automatic classification with concatenation of deep and handcrafted features of histological images for breast carcinoma diagnosis

Multimedia Tools and Applications - The second leading cause of death from cancer among women is breast cancer. In order to prevent avoidable deaths, early detection is extremely necessary....     

A multiple technical approach to the study of apoptotic cell micronuclei

Apoptotic micronuclei have been studied, in different cell types, from a morphologic and functional point of view. Conventional electron microscopy, in various staining conditions, selective cytochemistry for DNA, and freeze fracture for the analysis of chromatin fiber organization and size were performed. In situ TdT and Pol I immunofluorescent techniques were carried out to detect double- and single-strand DNA breaking points by confocal laser scanning microscopy. Apoptotic cell ultrathin cryosections were also performed and were analysed by field emission in lens scanning electron microscopy. Double/single strand massively cleaved DNA was detected in micronuclei, with a highly supercoiled, uniformly packed, very dense arrangement.     

Ethics Exercises for Civil,Environmental, and Geological Engineers

The practices of civil, environmental, and geological engineering share many common ethical dilemmas. These fields typically require extensive interaction with clients and regulatory agencies, while dealing with unpredictable earth materials for design and uncertain design parameters. Consequently, a capstone design course must address not only technical issues, but also a wide range of ethical and behavioral issues. This study presents a series of exercises used in the classroom to teach these issues through dealing with “gray” ethical areas, concepts of advocacy and the use of compromise, relating specific stories to global concepts, proper behavior in the corporate environment, and the influence of corporate culture on ethical decisions. The exercises were designed to incorporate a variety of active learning styles, including individual and group writing, group short answer, group design, and role playing as an individual and as part of a team. Only a small commitment of class time is required to complete these exercises, roughly six lecture periods and one laboratory period.     

Effects of Ta5+ doping on microstructure evolution,dielectric properties and electrical response in CaCu3Ti4O12 ceramics

The effects of Ta⁵⁺ substitution on the microstructure, electrical response of grain boundary, and dielectric properties of CaCu₃Ti₄O₁₂ ceramics were investigated. The mean grain size decreased with increasing Ta⁵⁺ concentration, which was ascribed to the ability of Ta⁵⁺ doping to inhibit grain boundary mobility. This can decrease dielectric constant values. Grain boundary resistance and potential barrier height of CaCu₃Ti₄O₁₂ ceramics were reduced by doping with Ta⁵⁺. This results in enhancement of dc conductivity and the related loss tangent. Influence of charge compensations on microstructure and intrinsic electrical properties of grain boundaries resulting from the effects of replacing Ti⁴⁺ with Ta⁵⁺ are discussed. The experimental data and variation caused by the substitution of Ta⁵⁺ can be described well by the internal barrier layer capacitor model based on space charge polarization at the grain boundaries.     

Discovery and Characterization of Multiple Classes of Human CatSper Blockers

The cation channel of sperm (CatSper) is a validated target for nonhormonal male contraception, but it lacks selective blockers, hindering studies to establish its role in both motility and capacitation. Via an innovative calcium uptake assay utilizing human sperm we discovered novel inhibitors of CatSper function from a high-throughput screening campaign of 72,000 compounds. Preliminary SAR was established for seven hit series. HTS hits or their more potent analogs blocked potassium-induced depolarization and noncompetitively inhibited progesterone-induced CatSper activation. CatSper channel blockade was confirmed by patch clamp electrophysiology and these compounds inhibited progesterone- and prostaglandin E1-induced hyperactivated sperm motility. One of the hit compounds is a potent CatSper inhibitor with high selectivity for CatSper over hCav1.2, hNav1.5, moderate selectivity over hSlo3 and hERG, and low cytotoxicity and is therefore the most promising inhibitor identified in this study. These new CatSper blockers serve as useful starting points for chemical probe development and drug discovery efforts.     

Improved Dielectric and Nonlinear Electrical Properties of Fine‐Grained CaCu3Ti4O12 Ceramics Prepared by a Glycine‐Nitrate Process

Pure CaCu₃Ti₄O₁₂ was successfully prepared by a glycine‐nitrate process using a relatively low calcination temperature and short reaction time of 760°C for 4 h. Fine‐grained CaCu₃Ti₄O₁₂ ceramics with dense microstructure and small grain size were obtained after sintering for 1 h. The nonlinear coefficient of a fine‐grained CaCu₃Ti₄O₁₂ ceramic calculated in the range 1–10 mA/cm² was found to be very high of ~16.39 with high breakdown electric field strength of 1.46 × 10⁴ V/cm. This fine‐grained CaCu₃Ti₄O₁₂ ceramic also exhibited a very low loss tangent of 0.017 at 20°C with temperature stability over the range ?55°C to 85°C. The grain growth rate of the CaCu₃Ti₄O₁₂ ceramics was found to be very fast after increasing the sintering time from 1.5 to 3 h, leading to formation of a coarse‐grained CaCu₃Ti₄O₁₂ ceramic with grain size of about 100–200 μm. The dielectric permittivity of this coarse‐grained ceramic was found to be as high as 1.03 × 10⁵ with a low loss tangent of 0.054.     

Thermal characteristics and temperature profile changes of structurally different polyethylenes with peroxide modifications

Crosslinking and processing characteristics of polyethylenes (PEs) with different molecular architectures, namely high‐density polyethylene (HDPE), linear low‐density polyethylene (LLDPE), and low‐density polyethylene (LDPE), were studied with regard to the effects of peroxide modifications and coolant flow rates. Dicumyl peroxide (DCP) and di‐tert‐butyl peroxide (DTBP) were used as free‐radical inducers for crosslinking the PEs. The characteristics of interest included normalized gel content, real‐time temperature profiles and their cooling rates, exothermic period, crystallinity level, crystallization temperature, and heat distortion temperature. The experiments showed that LDPE exhibited the highest normalized gel content. The real‐time cooling rates, taken from the temperature profiles for all PEs before the crystallization region, were greater than those after the crystallization region. The cooling rate of the PEs increased with the presence of DCP, whereas the crystallization temperature of the PEs was lowered. The HDPE appeared to show the longest exothermic period as compared with those of the LLDPE and LDPE. The exothermic period showed an increase with increasing coolant flow rate, but it was decreased by the use of DCP. As for the effect of peroxide type, the gel content and cooling rate of the PE crosslinked by DCP were higher than those for the PE crosslinked by DTBP. The DTBP was the more effective peroxide for introducing crosslinks and simultaneously maintaining the crystallization behavior of the PE. J. VINYL ADDIT. TECHNOL., 20:80‐90, 2014. © 2014 Society of Plastics Engineers     

Effect of fin pitches on the optimum heat transfer performance of crimped spiral fin-and-tube heat exchangers

This study conducted experiments on the optimized fin pitch for crimped spiral fin-and-tube heat exchangers. The experiments covered a size range of 2.4–6.5 mm, which is the manufacturing limitation for this kind of fin. The water-flow arrangement used in this experiment combined the parallel cross-flow and the counter cross-flow in a two-row configuration. Ambient air was used as the working fluid on the air-side, and hot water was used on the tube-side. The effects of fin pitches on the heat transfer coefficient and pressure drop characteristics were studied. The results clearly showed that the convective heat transfer coefficient (h_o) for a fin pitch of 2.4 mm is relatively low compared with that of other fin pitches with the same air frontal velocity. Using larger fin pitches (i.e., 4.2, 6.2, and 6.5 mm) resulted in negligible differences in the pressure drop. Moreover, this work introduces the parameter of three performances indexes, which can be expressed as the ratio of the desired output to the required input, for optimization purposes. Due to the difference in optimum fin pitch obtained by these performance indexes, an intersection analysis was conducted. The results indicated that the optimum fin pitch is 4.2 mm for this work, which could be valuable for the effective design for industrial thermal-system applications.     

Dielectric properties and electrical response of grain boundary of Na1/2La1/2Cu3Ti4O12 ceramics

The dielectric properties and electrical response of grain boundaries of Na_1/2La_1/2Cu₃Ti₄O₁₂ ceramics were investigated as a function of temperature. High dielectric permittivity (6.1–8.7 × 10³) and low loss tangent (0.032–0.038 at 10 kHz) were observed in Na_1/2La_1/2Cu₃Ti₄O₁₂ ceramics. Through analyses using complex impedance and electric modulus, it was found that the dielectric properties of Na_1/2La_1/2Cu₃Ti₄O₁₂ ceramics are closely related to the electrical response of grain boundaries. The investigation of non-Ohmic characteristics at various temperatures suggests that the potential barrier at the grain boundaries of Na_1/2La_1/2Cu₃Ti₄O₁₂ ceramics is due to the Schottky effect. The giant low frequency dielectric response in Na_1/2La_1/2Cu₃Ti₄O₁₂ ceramics is attributed to Maxwell–Wagner polarization at the grain boundaries.