New isothermal equation of state of solids applied to high pressures

In the present paper, a new two-parameter inverted equation of state (EOS) is developed which is found to be working very well in the high-pressure region. To check its success and validity, this EOS has been applied in a number of solids. The computed volume compression is found to be in very good agreement with the experimental data in the whole range of pressure in all the solids. The minimum and the maximum pressure range used in the present study is 0–320 kbar and 0–3000 kbar, respectively.     

Synthesis of 1-beta-D-(5-deoxy-5-iodoarabinofuranosyl)-2-nitroimidazole (beta-IAZA): a novel marker of tissue hypoxia

The present work describes the synthesis of the beta-isomer of 1-alpha-D-(5-deoxy-5-iodoarabinofuranosyl)-2-nitroimidazole (IAZA). Radioiodinated IAZA ((123)I-IAZA) has been extensively studied as a radiopharmaceutical for the diagnosis of regional and/or focal tissue hypoxia in a variety of clinical pathologies. The beta-anomer of IAZA, 1-beta-D-(5-deoxy-5-iodoarabinofuranosyl)-2-nitroimidazole (beta-IAZA, 1), was synthesized via an unconventional route starting from 1-beta-D-(ribofuranosyl)-2-nitroimidazole (AZR), with a change of configuration at the C-2'-position to afford 1-beta-D-(arabinofuranosyl)-2-nitroimidazole (beta-AZA, 7). Nucleophilic iodination of the 5'-O-toluenesulfonyl-2',3'-di-O-acetyl precursor of beta-AZA, 9, followed by deprotection, afforded 1 in satisfactory yield. beta-IAZA (1) was also synthesized from 7 using molecular iodine and triphenylphosphine.     

Enhanced Four-Electron Selective Oxygen Reduction Reaction at Carbon-Nanotube-Supported Sulfonic-Acid-Functionalized Copper Phthalocyanine

In the present work, the oxygen reduction reaction (ORR) is explored in an acidic medium with two different catalytic supports (multi-walled carbon nanotubes (MWCNTs) and nitrogen-doped multi-walled carbon nanotubes (NMWCNTs)) and two different catalysts (copper phthalocyanine (CuPc) and sulfonic acid functionalized CuPc (CuPc-SO₃⁻)). The composite, NMWCNTs-CuPc-SO₃⁻ exhibits high ORR activity (assessed based on the onset potential (0.57 V vs. reversible hydrogen electrode) and Tafel slope) in comparison to the other composites. Rotating ring disc electrode (RRDE) studies demonstrate a highly selective four-electron ORR (less than 2.5 % H₂O₂ formation) at the NMWCNTs-CuPc-SO₃⁻. The synergistic effect of the catalyst support (NMWCNTs) and sulfonic acid functionalization of the catalyst (in CuPc-SO₃⁻) increase the efficiency and selectivity of the ORR at the NMWCNTs-CuPc-SO₃⁻. The catalyst activity of NMWCNTs-CuPc-SO₃⁻ has been compared with many reported materials and found to be better than several catalysts. NMWCNTs-CuPc-SO₃⁻ shows high tolerance for methanol and very small deviation in the onset potential (10 mV) between the linear sweep voltammetry responses recorded before and after 3000 cyclic voltammetry cycles, demonstrating exceptional durability. The high durability is attributed to the stabilization of CuPc-SO₃⁻ by the additional coordination with nitrogen (Cu-N_x) present on the surface of NMWCNTs.     

Molecular Dynamics Simulations of Water-Mediated Cholesterol Capture within an Open-Ended Single-Walled Carbon Nanotube

The excess concentration of cholesterol in the bloodstream can be brought down to a safer level by utilizing a potential cholesterol-binding agent such as a carbon nanotube (CNT). Here, we have probed solvent-mediated interactions between cholesterol and CNT by performing molecular dynamics simulations and potential-of-mean force (PMF) calculations. Simulations predict favorable interactions between water-mediated cholesterol and CNT owing to strong mutual interactions between them, whereas water plays an opposing role in the association. The breakdown of PMF into its enthalpic and entropic contributions indicates that contrary to traditional entropy-driven hydrophobic association, the cholesterol encapsulation within a CNT is primarily driven by enthalpy.     

Three component tandem reactions involving protected 2-amino indoles, disubstituted propargyl alcohols, and I2/ICl: iodo-reactant controlled synthesis of dihydro-α-carbolines and α-carbolines via iodo-cyclization/iodo-cycloelimination

Two simple, highly efficient three component tandem reactions for the synthesis of diversified N^aN^b di-carbamate-4,9-dihydro-3-iodo-α-carbolines and N^a-carbamate-3-iodo-α-carbolines have been described. The strategy involves one-pot condensation of bis-carbamate protected 2-amino indoles with disubstituted propargyl alcohols and I₂/ICl. The salient feature of the reaction involves iodocyclo-elimination of N^b-linked carbamate under mild condition in the final step.     

Enzymatic oxidation of tert-butylcatechol in the presence of sulfhydryl compounds: Application to the amperometric detection of penicillamine

The high sensitivity that can be attained using an enzymatic system and mediated by 4-tert-butylcatechol (4-TBC) has been verified by on-line interfacing of a rotating biosensor and continuous flow/stopped-flow/continuous-flow processing. Horseradish peroxidase, HRP, [EC 1.11.1.7], immobilized on a rotating disk, in presence of hydrogen peroxide catalyzed the oxidation of 4-TBC, whose back electrochemical reduction was detected on glassy carbon electrode surface at −150 mV. Thus, when penicillamine (PA) was added to the solution, these thiol-containing compounds participate in Michael type addition reactions with 4-TBC to form the corresponding thioquinone derivatives, decreasing the peak current obtained proportionally to the increase of its concentration. The highest response for PA was obtained around pH 7. This method could be used to determine PA concentration in the range 0.02-80 μM (r = 0.998). The determination of PA was possible with a limit of detection of 7 nM, in the processing of as many as 50 samples per hour. The HRP-rotating biosensor was successfully applied to the determination of PA in pharmaceutical formulations.     

Reliable Technique for the Determination of Sodium Dodecyl Sulphate by Crystal Violet in Relation to the Effluents of Durg‐Bhilai Region

A simple spectrophotometric method applicable to waste water bodies is developed for the determination of anionic surfactant (AS). An ion‐association complex is formed between an anionic surfactant Sodium dodecyl sulphate (SDS) and a cationic dye Crystal Violet (CV). The dark blue colored complex can be easily extracted in organic solvent benzene. The absorbance of the complex in benzene layer is measured spectrophotometrically at maximum wave length (λ max) of 565 nm. Under the optimal experimental conditions, absorbance of the organic extractant obeyed Beer's law over the range of 0.75–10.00 μg mL^?1 of SDS and the LOD was 0.01312 μg L^?1. It is noticed that the present method is much easier, less time consuming and applicable to accelerated urbanization and industrial development found in newly formed Chhattisgarh state in Central India. The validity of the method was tested in regionalized industrial and domestic waste water runoff.     

Ultratrace Analysis of Dopamine Using a Combination of Imprinted Polymer-Brush-Coated SPME and Imprinted Polymer Sensor Techniques

A combination approach in solid-phase microextraction, based on a molecularly imprinted polymer-brush coating on an optical fiber coupled with a complementary molecularly imprinted polymer sensor, has been adopted for isolation, preconcentration, and analysis of dopamine at ultratrace levels in highly dilute aqueous samples. This combination enabled enhanced (up to 8.5-fold) preconcentration of the analyte, which is appropriate for achieving a stringent detection limit in clinical diagnosis of several neurodegenerative diseases. The detection limit of dopamine in biological samples was 0.018 ng mL^?1 with a relative standard deviation less than 2.1% and without any non-specific contributions.     

Towards a queueing-based framework for in-network function computation

We seek to develop network algorithms for function computation in sensor networks. Specifically, we want dynamic joint aggregation, routing, and scheduling algorithms that have analytically provable performance benefits due to in-network computation as compared to simple data forwarding. To this end, we define a class of functions, the Fully-Multiplexible functions, which includes several functions such as parity, MAX, and kth-order statistics. For such functions we characterize the maximum achievable refresh rate of the network in terms of an underlying graph primitive, the min-mincut. In acyclic wireline networks we show that the maximum refresh rate is achievable by a simple algorithm that is dynamic, distributed, and only dependent on local information. In the case of wireless networks we provide a MaxWeight-like algorithm with dynamic flow-splitting, which is shown to be throughput-optimal.