Testosterone treatment in men with erectile disorder and low levels of total testosterone in serum

Since decreased serum levels of testosterone (T) do not necessarily predict good outcome of testosterone treatment for erectile disorder, the purpose, of this study was to determine which men with erectile disorder and decreased serum levels might benefit from treatment. From a sample of 31 men (mean age = 39 years), 15 (48%) with erectile disorder and decreased serum levels of T responded well after 8 weeks of testosterone treatment (100 mg of testosterone propionate in the sustained-release form given im once a week). Good treatment outcome was associated with several variables, but only high levels of luteinizing hormone (LH) and low values of the T/LH (testosterone/LH) ratio consistently emerged as significant correlates and/or predictors of effective treatment. Levels of LH above 7.5 IU/L or the values of the T/LH ratio equal to or below 0.87 nmol/IU in patients with erectile disorder and decreased serum levels of T suggest that testosterone treatment may be effective.     

Determinants of users’ intention to adopt m-commerce: an empirical analysis

The fast-growing penetration of mobile devices and recent advances in mobile technologies have led to the development of increasingly sophisticated services such as m-shopping for goods or services and m-payment. However, although the number of mobile subscribers is increasing, levels of actual m-commerce activities in many cases remain low. Determining what influences users’ intention to use m-commerce is therefore of growing importance. The purpose of this study was to investigate possible factors. To this aim, we developed a conceptual user adoption model based on technology acceptance model variables and on specific factors such as social influence, personal innovativeness, customization, and individual mobility. The empirical results show that social influence and customization significantly affect perceived usefulness; mobility, customization, and personal innovativeness significantly affect perceived ease of use; and perceived usefulness and perceived ease of use have a direct positive effect on behavioral intention.     

Effects of thermal treatment of nanostructured trititanates on their crystallographic and textural properties

Nanostructured titanates (TTNT) with general formula Na_xH_2−xTi₃O₇·nH₂O were synthesized by hydrothermally reacting different TiO₂ anatase (distinct crystal sizes) with NaOH at 120 °C followed by washing with water or diluted acid and drying of the precipitate. The resulting powders with different sodium contents were submitted to various calcination temperatures up to 800 °C and each calcined product was characterized as for its phase structure, composition, crystallite size and textural properties, namely BET surface area, mesopore volume and pore size distribution. Thermal transformations of TTNT samples were investigated by monitoring the modifications on crystallographic (X-ray diffraction) and textural (N₂ desorption isotherms) properties, revealing the influence of the type of starting anatase and sodium content over the stability of TTNT. Moreover, a detailed study on the reduction of the interlayer distance in TTNT samples upon thermal treatment allowed corroborating the formation of an intermediate nanostructured hexatitanate, just before phase transformation into the corresponding TiO₂ polymorphs and/or titanate crystals, depending on the sodium content and calcination temperature.     

Space-time iterative and multistage receiver structures for CDMAmobile communication systems

We propose novel space-time multistage and iterative receiver structures and examine their application in code division multiple access (CDMA) mobile communication systems. In particular we derive an expression for weighting coefficients in parallel interference cancellers (PICs) in a system with a large number of users, where decision statistics bias is pronounced. We further examine the parameters in this expression and show how to obtain a practical partial cancellation method that allows on-line estimation of the weighting coefficients. In the proposed multistage PIC, the coefficients are calculated by using only the variances of the detector outputs. We also examine an iterative PIC and observe that this receiver has similar limitations as the multistage PIC. The application of the novel parallel interference cancellation strategy in the iterative receiver structure results in a spectacular system capacity improvement with a negligible complexity increase relative to the standard iterative receiver. The performance of the proposed receivers is further enhanced by receiver adaptive array antennas and space-time processing     

Al2Mo3O12/polyethylene composites with reduced coefficient of thermal expansion

Recently, polymer composites reinforced with low fractions of thermomiotic nanoceramics have triggered a lot of research. The efforts have been focused on achieving considerable reduction of the coefficient of thermal expansion (CTE) of polymeric materials without deterioration of other physical properties. In this context, polyethylene (PE) composites reinforced with different loads of Al₂Mo₃O₁₂ nanofillers (0.5–4 mass %) were fabricated by micro-compounding. To enhance the interfacial interaction between the two components, chemical functionalization of Al₂Mo₃O₁₂ was performed with vinyltrimethoxysilane (VTMS) prior to micro-compounding. Infrared spectroscopy and thermogravimetry demonstrated the successful grafting of VTMS on the Al₂Mo₃O₁₂ surface. The composites showed strongly decreased CTEs, up to 46 % reduction for loadings of 4 mass % compared with neat PE, suggesting intimate filler–matrix interactions. The variation of CTEs of the composites in terms of the filler fraction was successfully described by Turner’s model allowing calculation of the bulk modulus of monoclinic Al₂Mo₃O₁₂ (13.6 ± 2.6 GPa), in agreement with the value obtained by an ultrasonic method. The thermal stability of the composites was improved, although the addition of functionalized fillers decreased the degree of crystallinity of the PE to a small extent. The Young’s modulus and yield strength of the composites increased from 6.6 to 19.1 % and 4.0–6.0 %, respectively, supporting the existence of strong filler–matrix interactions, contributing to an efficient load transfer. Finite element analysis of thermal stresses indicated absence of plastic deformation of the matrix or fracture of the nanofillers, for a 100 K temperature drop.     

Complex thermal expansion properties of Al-containing HZSM-5 zeolite: A X-ray diffraction, neutron diffraction and thermogravimetry study

Thermal expansion of re-hydrated, Al-containing HZSM-5 was studied by different diffraction techniques, as well as, through thermogravimetry. It is concluded that the nature of the remarkable shift of thermal expansion properties, that occurs in air, between 350 °C and 400 °C, where the coefficient of thermal expansion changes from positive to negative is due to dehydration of HZSM-5 and not due to dealumination. The intrinsic thermal expansion properties of dehydrated HZSM-5 are observed in the second cycle of neutron diffraction experiments performed in vacuum (10⁻⁵ Torr). Near zero thermal expansion was observed in the temperature interval between 100 °C and 400 °C. These intrinsic thermal properties were rationalized in terms of the rigid unit mode model.     

Acyl Poly(Glycerol-Succinic Acid) Oligoesters: Synthesis,Physicochemical and Functional Properties,and Biodegradability

Biobased surfactants were synthesized using poly(glycerol-succinate) as the polar head group and variable acyl groups as hydrophobic tails. Acyl chain lengths ranged from 8 to 14 carbon atoms. The resulting oligomeric surfactants were characterized by quantitative ¹³C nuclear magnetic resonance (NMR), acid values and size exclusion chromatography. Investigation of the physicochemical properties of the acyl poly(glycerol-succinate) surfactants revealed their potential for use in a wide array of applications. The acyl poly(glycerol-succinate) functional properties appeared to be particularly concentration-dependent. This study highlights the relative impact of acyl chain length on the polymeric structure, physicochemical and functional behaviors, and biodegradability of the acyl poly(glycerol-succinate) surfactants.     

Hydrothermal synthesis, crystal structure and thermal stability of Ba-titanate nanotubes with layered crystal structure

BaTi₃O₇·nH₂O nanotubes have been synthesized through a hydrothermal reaction between Na-rich trititanate nanotubes and Ba(OH)₂ within the pH range 12–8.2. These nanotubes possess the same layered crystal structure of the precursor Na_2−xH_xTi₃O₇·nH₂O. They also keep the morphology of their precursor Na-trititanate nanotubes used in the synthesis, having an external diameter of 20–25 nm. The BaTi₃O₇·nH₂O nanotubes remained fully stable up to 300 °C, while nanotubular form continues to exist up to 600 °C, together with amorphous particles.