A series expansion method aided design of current mode second generation current conveyor based active control circuit

Current mode circuits are receiving considerable interest from engineering community due to their unique characteristics that are not found in their voltage mode counterparts. This paper presents a series method based design of a current conveyor active control circuit. An algorithm based on the principle of the series expansion of the pulse transfer function is employed for obtaining the transfer function of the controller. The controller is subsequently realized using the second generation current conveyors. The proposed methodology is used to design a CCII controller for a practical system, which is subsequently simulated using the AD844 IC’s in the NI’s Multisim simulation tool. Subsequently, the controller was designed and the comparisons are drawn between the experimental and simulation results in order to validate the approach.

     

Polymerizable sol–gel synthesis of nano-crystalline WO3 and its photocatalytic Cr(VI) reduction under visible light

A polymerizable sol–gel approach has been employed to synthesize bulk and nano-crystalline WO₃. A W-containing sol–gel resin is formed and subjected to thermally induced free radical polymerization followed by calcination at 450, 650 and 850 °C. TGA analysis was performed to reveal the calcination temperature required for WO₃ formation. The synthesized oxides have been characterized with XRD, SEM, XPS, TEM and diffuse reflectance spectroscopy to probe the crystallinity, surface morphology and electronic structures. BET surface area measurements were carried out for the synthesized materials to follow the effect of calcination temperature on surface area. The calcination temperature was found to be crucial in tuning the crystallinity and non-stoichiometry of the materials. The synthesized catalysts were explored for the efficiency of Cr(VI) photoreduction in aqueous medium under visible light and the results are correlated with the structural and electronic properties of the materials.     

Heterogeneous cycloaddition of styrene oxide with carbon dioxide for synthesis of styrene carbonate using reusable lanthanum–zirconium mixed oxide as catalyst

Clean Technologies and Environmental Policy - Development of environmentally benign green processes for utilization of carbon dioxide to synthesize value-added compounds using heterogeneous...     

Renal dysplasia masquerading as a renal mass in a child on hemodialysis

Pathological renal mass is uncommon in children. It is important to differentiate this from a benign mass or mass‐like lesion (pseudomass) for proper management. Renal dysplasia is a common finding in patients with end stage renal disease and can mimic a renal mass. Here, we report a 16‐year‐old girl on hemodialysis who was found to have a nodular right renal mass in the sonogram. Magnetic resonance imaging confirmed the nodular mass. She underwent right nephrectomy and the histopathology revealed features of renal dysplasia and end stage kidney disease without any evidence of malignancy. No further treatments were necessary. This case demonstrates that a nodular renal mass in dialysis patients does not always mean malignancy and could be a pseudomass from severe renal dysplasia. Since a sonogram may not be able to clearly define the etiology of solid mass in these patients, further evaluations including a renal histology and/or other imaging modalities are often necessary.     

Mixed Nanosized Polymeric Micelles as Promoter of Doxorubicin and miRNA‐34a Co‐Delivery Triggered by Dual Stimuli in Tumor Tissue

Dual stimuli‐sensitive mixed polymeric micelles (MM) are developed for co‐delivery of the endogenous tumor suppressor miRNA‐34a and the chemotherapeutic agent doxorubicin (Dox) into cancer cells. The novelty of the system resides in two stimuli‐sensitive prodrugs, a matrix metalloproteinase 2 (MMP2)‐sensitive Dox conjugate and a reducing agent (glutathione, GSH)‐sensitive miRNA‐34a conjugate, self‐assembled in a single particle decorated with a polyethylene glycol corona for longevity, and a cell‐penetrating peptide (TATp) for enhanced intracellular delivery. The MMP2‐sensitivity of the system results in threefold higher cytotoxicity in MMP2‐overexpressing HT1080 cells compared to low MMP2‐expressing MCF7 cells. Cellular internalization of Dox increases by more than 70% after inclusion of TATp to the formulation. MMP2‐sensitive MM also inhibits proliferation and migration of HT1080 cells. Moreover, GSH‐sensitive MM allows for an efficient downregulation of Bcl2, survivin, and notch1 (65%, 55%, and 46%, respectively) in HT1080 cells. Combination of both conjugates in dual sensitive MM reduces HT1080 cell viability to 40% and expression of Bcl2 and survivin. Finally, 50% cell death is observed in 3D models of tumor mass. The results confirm the potential of the MM to codeliver miRNA‐34a and doxorubicin triggered by dual stimuli inherent of tumor tissues.     

An evaluation of Māori values in multiscalar environmental policies governing Kaipara Harbour in New Zealand

Indigenous knowledge and values are increasingly found in watershed management to engage important stakeholders in the development of modern resource management practices and policies. This paper explores the integration of Māori values in water and land policies governing Kaipara Harbour in New Zealand as a case study for this approach. Multijurisdictional documents were analysed for the inclusion of nine well-established Māori values that have applications to land, water and natural resource management. The results of this study identified the most and least commonly mentioned values in policy documents, and a scalar trend in which integration of Māori values increased as the geographic scale and jurisdiction of the respective governing policies decreased.     

A Methodical Assessment of Floodplains in Mixed Land Covers Encompassing Bridges in Alabama State: Implications of Spatial Land Cover Characteristics on Flood Vulnerability

The mixed land covers encompassing bridges (MLB) are integral indicator of the socio-economic hydrological system, and their progressions are vital for flood risk assessment. However, most of the previous studies have neglected a thorough evaluation of MLBs (e.g., types, areas, and depths) on impacting flood vulnerability. This paper addresses this research gap by methodically assessing the spatial characteristics of MLBs in floodplains and their divergent impacts on flood vulnerability using four case studies of Alabama State in the USA. The hydrological and bridge data were synthesized from United States Geological Survey and National Bridge Inventory, respectively. A union of Hydrologic Engineering Center's-River Analysis System (HEC-RAS), Geographic Information System, and Surface Difference Model were employed to retrieve water surface profiles and floodplain assessments in MLBs. The results highlighted that the occurrence of floodplains was more correlated to flood depths compared to flood areas in the MLBs of Alabama. The spatial contribution of the diverse MLBs in producing deep (19%) and shallow (30%) flood depths in the bridges of Alabama were 49%, while medium flood depths were impacted only on 4% of the MLBs. The highest and lowest flood areas were noticed in the MLBs of pastures and mixed forests, respectively. Overall, the findings implied that the contribution of the individual MLBs in floodplains is multifaceted in the bridges of Alabama with spatially varying land cover distribution. Further, it is recommended that for assessing flood vulnerability, the stakeholders should focus not only on the MLBs but also on its spatially dynamic characteristics.

     

High-temperature thermoelectric properties of p-type skutterudites Ba0.15Yb x Co3FeSb12 and Yb y Co3FeSb9As3

Two series of p-type polycrystalline skutterudites, Ba_0.15Yb _x Co₃FeSb₁₂ and Yb _y Co₃FeSb₉As₃ with varying Yb concentrations, were synthesized by solid-state reaction and then densified by hot pressing. The phase and stoichiometries of the resulting materials were characterized by powder X-ray diffraction and energy dispersive spectroscopy, while their high-temperature transport properties were investigated from 300 to 800 K. The Seebeck coefficients and electrical resistivities increased linearly with increasing temperature for the double-filled specimens. The Seebeck coefficients and electrical resistivities did not change very much for the As-substituted specimens. The thermal conductivity for all specimens decreased with increasing temperature up to 700 K, corresponding to the plateau in the Seebeck coefficient, and then increased again due to bipolar diffusion. We find that double filling is a more feasible approach to thermoelectric property optimization than single filling with As substitution.     

Elicitation of Diosgenin Production in Trigonella foenum-graecum (Fenugreek) Seedlings by Methyl Jasmonate

The effects of methyl jasmonate (MeJA), an elicitor of plant defense mechanisms, on the biosynthesis of diosgenin, a steroidal saponin, were investigated in six fenugreek (Trigonella foenum-graecum) varieties (Gujarat Methi-2, Kasuri-1, Kasuri-2, Pusa Early Branching, Rajasthan Methi and Maharashtra Methi-5). Treatment with 0.01% MeJA increased diosgenin levels, in 12 days old seedlings, from 0.5%–0.9% to 1.1%–1.8%. In addition, MeJA upregulated the expression of two pivotal genes of the mevalonate pathway, the metabolic route leading to diosgenin: 3-hydroxy-3-methylglutaryl-CoA reductase (HMG) and sterol-3-β-glucosyl transferase (STRL). In particular, MeJA increased the expression of HMG and STRL genes by 3.2- and 22.2-fold, respectively, in the Gujarat Methi-2 variety, and by 25.4- and 28.4-fold, respectively, in the Kasuri-2 variety. Therefore, MeJA may be considered a promising elicitor for diosgenin production by fenugreek plants.