Developing an Information System for Sustainable Natural Resource Management in Alborz Watershed, Northern Iran

This article explores the potentials of systems analysis and design of information system for sustainable natural resource management. Soft and hard system analyses were performed to better understand the information needs and design of an information system for improving decision making for achieving sustainable natural resource management. In order to analyze the complex and soft systems situations for developing an effective information system, which meets related actors’ changing needs, a conceptual model inspired by soft systems methodology (SSM) was developed. This model is based on information derived from twelve farmers who were purposely selected to represent diverse conditions and 23 agricultural extension experts across the Alborz Watershed in Mazandaran Province, located in northern Iran. Since a conceptual model resulting from SSM is not in itself sufficient as the basis for the implementation of information systems, a hard system methodology was used to structure the data handling by using unified modeling language. This research has shown the promising potentiality of using soft system analysis methodology as a preliminary step to the actual design of an information system in the natural resource management situation in the watershed system level when combined with hard system analysis methods.     

Inhibition of glucose transport in human erythrocytes by 2,3-dioxoindole (Isatin)

10 mM isatin (2,3-dioxoindole) inhibited glucose influx into human erythrocytes by over 30%. The inhibition is of the competitive type, where the affinity constant (K_t) was increased from 5.71 (control) to 11.11 mM in the presence of isatin with no change in V_max (130 nmol/min/ml packed cells). The observed inhibition of sugar transport by isatin was not mediated through membrane–SH groups accessible to iodoacetate, iodoacetamide, DTNB, DNP or sodium arsenite. Isatin inhibited sugar transport in the presence of 2 mM harmaline, an alkaloid inhibitor of Na⁺, K⁺–ATP_ase activity. The inhibition was non additive which suggests that these two compounds interact with the same or a similar site on the erythrocyte membrane.     

Effect of chronic hypo and hypervitaminosis C on the brush border enzymes and the intestinal uptake of glucose and alanine

Summary Brush border sucrase and alkaline phosphatase activities are considerably enhanced in the intestine of ascorbic acid deficient guinea-pigs. Similar increase in the uptake of D-glucose and L-alanine also occurs in chronic vitamin C deficiency. However the permeability of D-glucose and L-alanine in the intestine of animals fed with large doses of vitamin C is severely depressed, with a reduction in the levels of sucrase and alkaline phosphatase activities.     

Cardiac angiogenic imbalance leads to peripartum cardiomyopathy

Peripartum cardiomyopathy (PPCM) is an often fatal disease that affects pregnant women who are near delivery, and it occurs more frequently in women with pre-eclampsia and/or multiple gestation. The aetiology of PPCM, and why it is associated with pre-eclampsia, remain unknown. Here we show that PPCM is associated with a systemic angiogenic imbalance, accentuated by pre-eclampsia. Mice that lack cardiac PGC-1α, a powerful regulator of angiogenesis, develop profound PPCM. Importantly, the PPCM is entirely rescued by pro-angiogenic therapies. In humans, the placenta in late gestation secretes VEGF inhibitors like soluble FLT1 (sFLT1), and this is accentuated by multiple gestation and pre-eclampsia. This anti-angiogenic environment is accompanied by subclinical cardiac dysfunction, the extent of which correlates with circulating levels of sFLT1. Exogenous sFLT1 alone caused diastolic dysfunction in wild-type mice, and profound systolic dysfunction in mice lacking cardiac PGC-1α. Finally, plasma samples from women with PPCM contained abnormally high levels of sFLT1. These data indicate that PPCM is mainly a vascular disease, caused by excess anti-angiogenic signalling in the peripartum period. The data also explain how late pregnancy poses a threat to cardiac homeostasis, and why pre-eclampsia and multiple gestation are important risk factors for the development of PPCM.     

CuCrW(Al2O3) nanocomposite: mechanical alloying,microstructure, and tribological properties

The effect of alumina nanoparticle addition on the microstructure and tribological properties of a CuCrW alloy was investigated in this work.Mechanical alloying was carried out in a satellite ball mill.The tribological properties of the samples were evaluated using pin-on-disk wear tests with different pins (alumina,tungsten carbide,and steel pins).The results indicated that the tungsten carbide pin had a lower coefficient of friction than the alumina and steel pins because of its high hardness and low surface roughness.In addition,when the sliding rate was decreased,the weight-loss rate increased.The existence of alumina nanoparticles in the nanocomposite led to a lower weight-loss rate and to a change in the wear mechanism from adhesive to abrasive.     

Fabrication of Fe–TiC–Al2O3 composites on the surface of steel using a TiO2–Al–C–Fe combustion reaction induced by gas tungsten arc cladding

The aim of the present study was to fabricate Fe–TiC–Al₂O₃ composites on the surface of medium carbon steel. For this purpose, TiO₂–3C and 3TiO₂–4Al–3C–xFe (0 ≤ x ≤ 4.6 by mole) mixtures were pre-placed on the surface of a medium carbon steel plate. The mixtures and substrate were then melted using a gas tungsten arc cladding process. The results show that the martensite forms in the layer produced by the TiO₂–3C mixture. However, ferrite–Fe₃C–TiC phases are the main phases in the microstructure of the clad layer produced by the 3TiO₂–4Al–3C mixture. The addition of Fe to the TiO₂–4Al–3C reactants with the content from 0 to 20wt% increases the volume fraction of particles, and a composite containing approximately 9vol% TiC and Al₂O₃ particles forms. This composite substantially improves the substrate hardness. The mechanism by which Fe particles enhance the TiC + Al₂O₃ volume fraction in the composite is determined.     

Pseudo-<Emphasis Type="Italic">in-situ</Emphasis> stir casting: a new method for production of aluminum matrix composites with bimodal-sized B<Subscript>4</Subscript>C reinforcement

A new method was applied to produce an Al-0.5wt%Ti-0.3wt%Zr/5vol%B₄C composite via stir casting with the aim of characterizing the microstructure of the resulting composite. For the production of the composite, large B₄C particles (larger than 75 μm) with no pre-heating were added to the stirred melt. Reflected-light microscopy, X-ray diffraction, scanning electron microscopy, field-emission scanning electron microscopy, laser particle size analysis, and image analysis using the Clemex software were performed on the cast samples for microstructural analysis and phase detection. The results revealed that as a consequence of thermal shock, B₄C particle breakage occurred in the melt. The mechanism proposed for this phenomenon is that the exerted thermal shock in combination with the low thermal shock resistance of B₄C and large size of the added B₄C particles were the three key parameters responsible for B₄C particle breakage. This breakage introduced small particles with sizes less than 10 μm and with no contamination on their surfaces into the melt. The mean particle distance measured via image analysis was approximately 60 μm. The coefficient of variation index, which was used as a measure of particle distribution homogeneity, showed some variations, indicating a relatively homogeneous distribution.     

CuCrW(Al<Subscript>2</Subscript>O<Subscript>3</Subscript>) nanocomposite: mechanical alloying,microstructure, and tribological properties

The effect of alumina nanoparticle addition on the microstructure and tribological properties of a CuCrW alloy was investigated in this work. Mechanical alloying was carried out in a satellite ball mill. The tribological properties of the samples were evaluated using pin-on-disk wear tests with different pins (alumina, tungsten carbide, and steel pins). The results indicated that the tungsten carbide pin had a lower coefficient of friction than the alumina and steel pins because of its high hardness and low surface roughness. In addition, when the sliding rate was decreased, the weight-loss rate increased. The existence of alumina nanoparticles in the nanocomposite led to a lower weight-loss rate and to a change in the wear mechanism from adhesive to abrasive.     

Cu-Zn-Al2O3 nanocomposites:study of microstructure,corrosion,and wear properties

Alumina nanoparticles were added to a Cu-Zn alloy to investigate their effect on the microstructural, tribological, and corrosion properties of the prepared alloys. Alloying was performed using a mixture of copper and zinc powders with 0vol% and 5vol% of α-Al nanopowder in a satellite ball mill. The results showed that the Cu-Zn solid solution formed after 18 h of mechanical alloying. The mechanically alloyed powder was compacted followed by sintering of the obtained green compacts at 750℃ for 30 min. Alumina nanoparticles were uniformly distributed in the matrix of the Cu-Zn alloy. The tribological properties were evaluated by pin-on-disk wear tests, which revealed that, upon the addition of alumina nanoparticles, the coefficient of friction and the wear rate were reduced to 20% and 40%, respectively. The corrosion properties of the samples exposed to a 3.5wt% NaCl solution were studied using the immersion and potentiodynamic polarization methods, which revealed that the addition of alumina nanoparticles reduced the corrosion current of the nanocomposite by 90%.