Improved electro-assisted removal of phosphates and nitrates using mesoporous carbon aerogels with controlled porosity

Three-activated carbon aerogels were synthesized by CO₂ activation of the materials prepared by the polycondensation of resorcinol and formaldehyde mixtures followed by supercritical drying. The obtained carbon aerogels were characterized and used as electrode materials for the electrosorption of sodium phosphate and nitrate. X-ray diffraction and Raman spectroscopy showed the dependence of the structural ordering of the aerogels with the resorcinol/catalyst ratio and the extent of activation. The electrosorption capacitance evaluated by cyclic voltammetry revealed large values for the activated samples containing a large contribution of mesopores, regardless the electrolyte salt. Due to an adequate combination of chemical and porous features, the desalting capacity of the activated carbon aerogel electrodes exceeded that of the as-prepared materials. The evaluation of the kinetic properties by chronocoulometric relaxation and impedance spectroscopy showed a decrease of time constant and resistances for highly mesoporous activated samples. A high deionization capacity and fast electrode discharge was detected for the deionization of sodium nitrate on the highly mesoporous activated aerogel. Data also showed the efficient electrosorption of ionic species on consecutive charge/discharge cycles, confirming the stability of the aerogel electrodes at the high applied potentials.     

Adjuvant therapy for osteosarcoma in dogs: results of randomized clinical trials using combined liposome-encapsulated muramyl tripeptide and cisplatin

Two randomized, double-blind clinical trials in dogs with spontaneous appendicular osteosarcoma treated with combination chemoimmunotherapy are reported. In both trials, dogs without overt metastasis underwent complete amputation of the affected limb. In trial 1, 40 dogs were treated with cisplatin chemotherapy [(CDDP), 70 mg/m2 i.v. every 28 days x 4]. Following CDDP, dogs without evidence of overt metastasis (n = 25) were randomized to receive liposome-encapsulated muramyl tripeptide phosphatidylethanolamine ](L-MTP-PE), 2 mg/m2 i.v.) or placebo liposomes (lipid equivalent) twice weekly for 8 weeks. Of 14 dogs in the placebo group, 13 (93%) died of metastasis; the median survival time was 9.8 months. Of 11 dogs in the L-MTP-PE group, 8 (73%) developed metastasis; the median survival time was 14.4 months, which was significantly longer than that of the placebo group (P < 0.01). In trial 2, 64 dogs received CDDP (70 mg/m2 i.v. every 21 days x 4) and were randomized to concurrently receive L-MTP-PE (2 mg/m2 i.v.) twice or once weekly, or placebo liposomes once weekly for 8 weeks. Median survival times were 10.3, 10.5, and 7.6 months, respectively. There were no significant differences among the three treatment groups in trial 2. Survival times for dogs receiving L-MTP-PE in trial 1 were significantly longer than those for dogs in trial 2 that received four doses of CDDP concurrently with twice weekly L-MTP-PE (P < 0. 04). The results of the first trial confirm our previous observation that L-MTP-PE has antimetastatic activity in dogs with osteosarcoma when given following amputation. The results of the second trial demonstrate that there is no survival advantage of administering L-MTP-PE concurrently with CDDP.     

MMP and TIMP expression pattern in pleural effusions of different origins

The matrix metalloproteinases (MMP) are proteolytic enzymes that are essentially involved in the turnover of the extracellular matrix (ECM). Their activity is counterbalanced by specific antagonists, the tissue inhibitors of metalloproteinases (TIMP). In this study, we sought to analyze the expression of MMP and TIMP isoforms in pleural effusions from 88 patients. We compared MMP and TIMP isoform expression in transudates (n = 21) and exudates (n = 67), the latter divided into exudates of paraneoplastic (n = 46) or parainfectious (n = 21) origin. Zymographic and Western blot analyses revealed constant expression of interstitial collagenase (MMP-1), gelatinase-A (MMP-2), and TIMP-1 in all 88 samples. In contrast, analyses of gelatinase-B (MMP-9) demonstrated a specific expression pattern, with high expression in exudates and lack of expression in transudates. Neutrophil collagenase (MMP-8) was detected in trace amounts, and correlated with the number of neutrophils in the effusion. Low levels of TIMP-2 were detected only in exudates and not in transudates. Quantitative analysis of the expression ratio of gelatinase-B to gelatinase-A revealed statistically significant differences between effusions of different origin. The ratio was highest in exudates of paraneoplastic origin and lowest in transudates. Our data thus suggest that interstitial collagenase, gelatinase-A, and TIMP-1 play a role in homeostasis of the pleural space in vivo as constitutively expressed proteins, whereas gelatinase-B and TIMP-2 expression are induced in specific disease states. These observations contribute to the understanding of the pathophysiology of pleural effusions, and may help to characterize and possibly distinguish effusions of different origin.     

Preparation and characterization of activated carbon from oil sands coke

Several million tonnes of oil sands coke are generated each year in Alberta, Canada as a by-product of bitumen upgrading. Due to its high carbon content, oil sands coke can be a suitable precursor for the preparation of activated carbon. In this study, delayed and fluid oil sands coke were physically activated in a muffle furnace under select conditions of activation time (2–6 h), temperature (800–900 °C), steam rate (0.3–0.5 mL/min), and activation atmosphere (CO₂, CO₂ + steam, and N₂ + steam). The activated products were characterized using thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, nitrogen adsorption, iodine and methylene blue tests. An increase in activation time and temperature resulted in higher surface areas in both delayed and fluid coke due to an enhanced etching of pores. An increase in steam rate led to the production of the highest specific surface area (577 m²/g) and iodine number (670 mg/g) within delayed coke; whereas, a lower steam rate resulted in the production of the highest specific surface area (533 m²/g) and iodine number (530 mg/g) in activated fluid coke samples.     

Microhardness studies of PMMA/natural rubber blends

The microhardness, H, of PMMA/natural rubber blends, prepared following the solution method has been investigated by means of the microindentation technique. Hardness changes are correlated with the variation of the glass transition temperature. The influence of temperature and degree of deformation on H were additionally examined. The inclusion of rubber particles in the PMMA matrix is shown to soften the blends. The variation of the micromechanical property at the phase boundary of polymer/rubber particle has been studied. Results reveal that H drastically drops at the interphase. In the case of the drawn materials, the indentation anisotropy (ΔH) is shown to gradually increase with the draw ratio, where ΔH is found to be higher for the PMMA/rubber blend than for the original PMMA. This result is explained by the higher orientation of the PMMA molecules near the periphery of stretched rubber particles. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 205–210, 2004     

Application of the Same-Stuff and Equal-Strength Laser Cladding Technology on the Repaired Semishrouded Impeller

0Cr17Ni4Cu4Nb powder was used to investigate the same-stuff laser repair(LR)technology on the semishrounded impeller.To improve the repaired effect,heat treatment was used after LR forming process.By means of optical microscopy,scan electron microscopy(SEM),micro-hardness tester and tensile tests,the microstructure of the coating was investigated and mechanical properties were measured.The experimental results show that cladding layer is well bonded to the substrate,the microstructure of the laser repaired zone(LRZ)is coarse martensite which will be refined after heat-treatment.The mechanical property experiments indicate that the micro-hardness and toughness would be increased after heat-treatment,the strength of LRZ after heat-treatment is 1050～1200 MPa,while the strength of normal laser repaired sample is 1000～1050 MPa.The refinement effect due to the heat treatment plays an important role in the improvement of the mechanical properties of samples.Overspeed examination and the real operation of the impeller after repairing also confirmed the reliability of this same-stuff and equal-strength laser cladding technology.     

获得高熔敷速度与低稀释率的等离子粉末堆焊方法

对传统的堆焊方法而言，提高熔敷速度与降低稀释率是矛盾的，能否协调这两方面因素，是实现高效高质堆焊效果的关键，分析了提高熔敷速度，降低稀释率的各种途径，并基于理论的分析与工艺验证，提出采用小压缩孔径，拉长粉末会交点于工件距离是同时获得高熔敷速度，低稀释率堆焊效果的有效途径。     

Ⅲ型预埋铁座铣削专用设备电气控制

本文介绍了一专用设备的电气控制原理     

中频变频器UFV故障探析

本文对中频变频器的UFV故障进行了系统试验和原因分析，并对UFV故障的关键因素进行了详细探析。     

T lymphocyte responses to anti-neutrophil cytoplasmic autoantibody (ANCA) antigens are present in patients with ANCA-associated systemic vasculitis and persist during disease remission

The cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel has been identified in the cardiac muscle of a number of mammalian species, including humans. The goal of this study was to begin quantifying the structural requirements necessary for arylaminobenzoate block of the CFTR channel. The cardiac cAMP-dependent Cl- current (ICl) was measured using the whole-cell arrangement of the patch-clamp technique in guinea pig ventricular myocytes during stimulation of protein kinase A with forskolin. At drug concentrations below the IC50 value for channel block, reduction of ICl by the arylaminobenzoates occurred in a strongly voltage-dependent manner with preferential inhibition of the inward currents. At higher drug concentrations, block of both the inward and outward ICl was observed. Increasing the length of the carbon chain between the benzoate and phenyl rings of the arylaminobenzoates resulted in a marked increase in drug block of the channel, with IC50 values of 47, 17, and 4 microM for 2-benzylamino-5-nitro-benzoic acid, 5-nitro-2-(2-phenylethylamino)-benzoic acid, and 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB), respectively. Increasing the carbon chain length further with the compound 5-nitro-2-(4-phenylbutylamino)-benzoic acid, caused no additional increase in the potency of drug block (IC50 = 4 microM). Inhibition of ICl by the arylaminobenzoates was modulated by the pH of the external solution; increasing the pH from 7.4 to 10.0 greatly weakened NPPB block, whereas decreasing the pH to 6.4 enhanced block. In addition, block of ICl was observed during intracellular dialysis of NPPB, and this action was not affected by raising the external pH.