Multi-institutional analysis of sequential intravesical gemcitabine and mitomycin C chemotherapy for non–muscle invasive bladder cancer

OBJECTIVE: Apart from cystectomy, few treatment options exist for the management of bacillus Calmette-Guerin refractory non–muscle invasive bladder cancer (NMIBC). We report a multi-institutional experience with sequential intravesical combination chemotherapy using gemcitabine and mitomycin C (MMC) for NMIBC in the treatment of high-risk patients. METHODS: We performed a retrospective review of patients who received 6 weekly treatments with sequential intravesical gemcitabine (1 g) and MMC (40 mg) chemotherapy for NMIBC. Gemcitabine was administered first and retained for 90 minutes and then drained. MMC was then administered directly after and retained for an additional 90 minutes. Forty-seven patients received treatment from 3 academic tertiary referral centers between 2000 and 2010. RESULTS: Forty-seven patients (median age 70, range 32–85; 36 males, 11 females) who previously failed a median of 2 intravesical treatments were reviewed. Complete response, 1-year, and 2-year recurrence-free survival rates for all patients were 68%, 48%, and 38%, respectively. Median recurrence-free survival for all patients was 9 months (range 1–80). Fourteen of 47 patients (30%) remained free of recurrence with a median time to follow-up of 26 months (range 6–80 mo). Ten patients required cystectomy. CONCLUSION: Sequential intravesical combination chemotherapy using gemcitabine and MMC appears to be a useful treatment for patients with high-grade NMIBC as well as those with prior bacillus Calmette-Guerin failure. Further prospective studies are warranted

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Synthesis and characterization of Sn–3.5Ag–XZn alloy nanoparticles by the chemical reduction method

An attempt was made to synthesize Sn-3.5Ag-0.5Zn alloy nanoparticles by chemical reduction method. The chemical precipitation was carried out by using NaBH4 as a reducing agent and poly-m-vinyl 2-pyrrolidone (PVP) as a stabilizer. The Zn content was varied from 0.5 to 3.5 wt%. The microstructure of the nanoparticles were determined by using techniques such as X-ray diffraction, transmission electron microscopy (TEM) and scanning electron microscopy (SEM), etc. X-ray diffraction patterns revealed that Ag3Sn was formed due to the successful alloying process. Other intermetallic compounds such as Ag4Sn and Ag5Zn8 were also obtained in the XRD patterns. Results on TEM revealed that the isolated particles were spherical in shape and the particle size varied from 2 to 10 nm. The high-resolution transmission electron microscopy (HRTEM) images for Sn-3.5Ag-0.5Zn alloys showed selected area diffraction patterns for Ag3Sn nanoparticles. However, diffraction patterns for compounds like Ag4Sn and Ag5Zn8 could not be obtained due to the strong aggregation of nanoparticles. The morphology of SnAgZn nanoparticles obtained by SEM revealed that the major particle size of SnAgZn nanoparticles were in the range of 60-80 nm

Effect of Cr3+ on the electrodeposition of nickel from acidic sulfate solutions

The effect of Cr3+ on the cathodic current efficiency (CE), deposit morphology, crystallographic orientations and polarisation behaviour during nickel electrodeposition from acidic sulfate solutions containing boric acid was investigated. A progressive decrease in CE was seen with increase in Cr3+ concentration showing a maximum decrease in CE of ∼10-13% at concentration ∼100 mg dm-3. The presence of Cr3+ did not change the fcc structure of the electrodeposited nickel but affected the peak intensities of the crystal planes. Polarisation of the cathode was seen in the presence of Cr3+ in the electrolyte along with a shift in the electroreduction potential of nickel (II) ion towards more negative values. The effect of Cr3+ on the electrokinetic parameters: Tafel slope (b), transfer coefficient (α) and exchange current density (i0) has also been investigated

Effect of Cd2+ on the electrodeposition of nickel from sulfate solutions. Part I: Current efficiency, surface morphology and crystal orientations

The effect of Cd2+ on the current efficiency, surface morphology and crystallographic orientations of the electrodeposited nickel from sulfate baths of varying compositions was investigated. The results indicated that Cd2+ had no significant effect on the current efficiency but there was a noticeable change in the surface morphology and deposit quality. The X-ray diffraction studies revealed that the (200) plane was the most preferred orientation and was not generally affected by the presence of Cd2+ in the electrolytic bath

Effect of pyridine and its derivatives on the electrodeposition of nickel from aqueous sulfate solutions. Part I: Current efficiency, surface morphology and crystal orientation

The effects of pyridine and its derivatives on current efficiency, surface morphology and crystallographic orientations of electrodeposited nickel from acidic sulfate solutions were investigated. The results indicated that the presence of pyridine and picolines had no significant effect on current efficiency. The deposits obtained were smoother, more compact and uniform with picolines than with pyridine. A significant change in surface morphology of the electrodeposits was observed and picolines were found to be better additives than pyridine, 4-picoline being the best. X-ray diffraction revealed that the (200) plane was the most preferred plane and was not affected by the presence of any of these additives in the electrolyte

Preparation of Sn–3.5Ag nano-solder by supernatant process

The nano-scaled Sn-3.5Ag solder was prepared successfully by a supernatant process in the present study. The morphology of the nano-particle was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. It was found from the SEM micrographs that the average diameter of the particle was 137 nm with a standard deviation of ±5 nm. From the TEM studies it was revealed that the particles aggregated into larger particles and the shape of the elongated particles were irregular. The composition of the alloy was also measured by an electron probe microanalyzer (EPMA) and energy dispersive spectroscopy (EDS), qualitatively and quantitatively. The eutectic element, Ag with a weight percentage of 3.5%, was found to be homogenous over all of the particles. Furthermore, the microstructure of the Sn-3.5Ag alloy was identified by X-ray diffraction. It was found that the trace element, Ag was dissolved in the matrix, a tetragonal system, without an intermetallic phase

Effect of Cd2+ on the electrodeposition of nickel from sulfate solutions. Part II: Polarisation behaviour

The effect of Cd2+ on the electrodeposition of nickel from a sulphate bath in the absence and presence of boric acid has been investigated. The presence of Cd2+ ion suppresses the nickel electrodeposition and shifts the deposition potential to more negative values. The cathodic polarisation is found to depend on the composition of the electrolytic bath. For the various baths investigated, the cathodic polarization order is found to decrease in the order NiSO4+H3BO3NiSO 4+H3BO3+Na2SO4NiSO 4+Na2SO4NiSO4. For the Ni 2+ electroreduction reaction on stainless steel and nickel substrates the exchange current density decreases with increase in Cd2+ concentration in the electrolytic bath. However the Tafel slope and transfer coefficient are unaffected

Effect of pyridine and its derivatives on the electrodeposition of nickel from aqueous sulfate solutions part II: Polarization behaviour

The electrochemical reactions occurring during electrodeposition of nickel from acidic sulfate solutions were examined by cyclic and linear sweep voltammetry techniques. The effect of pyridine, 2-picoline and 4-picoline on the electrode polarization behaviour and electron transfer parameter of the cathodic reduction process was also investigated. Strongest electrode polarization was seen with 4-picoline. The order of cathodic polarization was 4-picoline > 2-picoline > pyridine. Kinetic parameters such as Tafel slope, transfer coefficient and exchange current density were determined to analyse the nature of the electrode reactions. The exchange current density for nickel deposition on nickel and stainless steel substrates was in the order 4-picoline < 2-picoline < pyridine

Roles of organic and inorganic additives on the surface quality, morphology, and polarization behavior during nickel electrodeposition from various baths: A review

During the hydrometallurgical processing of nickel from raw materials, the leach liquors are found to be contaminated with several impurities. These impurities in the electrolytic cell affect the deposition characteristics as well as the kinetics and mechanism of nickel electrodeposition process resulting in lower current efficiency (CE) and poor nickel deposits. In order to improve the quality of the nickel deposits, it is imperative to use organic additives in the nickel plating bath to improve the structural, mechanical, and morphological properties of the deposits. Furthermore, it is usually observed that in spite of various purification techniques like cementation and solvent extraction, metals obtained at the cathode are usually contaminated with inorganic impurities. This review thus presents a comprehensive overview of some important studies and investigations performed on various inorganic and organic additives employed in nickel electrodeposition processes from various baths such as Watts, sulfate, acetate, formamide, lactate, and baths containing ionic liquids. The presence of metallic (inorganic) impurities in industrial electrolytes is very common. Most of these impurities affect the deposit’s characteristics, CE, deposition overvoltage, and cathode purity. Addition of inorganic cations such as Al3+, Mg2+, Mn2+, and Zn2+ did not have a significant effect on the CE; nevertheless, the physical appearance and crystallographic orientation of nickel deposits were significantly affected. Organic additives are usually added to the nickel electrolytic bath to counter the harmful effects of these metallic impurities entrained in the bath, where they also affect the growth and crystal building of the deposits through their adsorption onto the cathode surface. Most of these additives act as hydrogen inhibitors, crystal growth modifiers, brighteners, levelers, wetting agents, and stress reducers, and hence, their appropriate addition was important for the formation of fine-grained, smooth, and compact deposits. This review demonstrates that the quality of the nickel deposit was strongly affected if the concentration of the inorganic impurity in the nickel bath exceeded the tolerance limit. From this review article, the roles of various organic additives as a brightener, leveler, and antipitting agent, etc. in the Ni plating bath could be established, and these additives would play a significant role in the formation of bright, smooth, and coherent nickel deposits obtained during hydrometallurgical processing of laterite and sulfide ores in the metallurgical industry