Pd Target Research Articles

Quantitative estimation of plum pox virus targets acquired and transmitted by a single Myzus persicae

The viral charge acquired and inoculated by single aphids in a non-circulative transmission is estimated using plum pox virus (PPV). A combination of electrical penetration graph and TaqMan real-time RT-PCR techniques was used to establish the average number of PPV RNA targets inoculated by an aphid in a single probe (26,750), approximately half of the acquired ones. This number of PPV targets is responsible for a systemic infection of 20% on the inoculated receptor plants. No significant differences were found between the number of PPV RNA targets acquired after one and after five intracellular punctures (pd), but the frequency of infected receptor plants was higher after 5 pd. The percentage of PPV-positive leaf discs after just 1 pd of inoculation probe (28%/4,603 targets) was lower than after 5 pd (45.8%/135 x 10(6) targets). The methodology employed could be easily extended to other virus-vector-host combinations to improve the accuracy of models used in virus epidemiology.

In Vivo Pharmacodynamic Characterization of a Novel Plectasin Antibiotic, NZ2114, in a Murine Infection Model

NZ2114 is a novel plectasin derivative with potent activity against gram-positive bacteria, including multiply drug-resistant strains. We used the neutropenic murine thigh infection model to characterize the time course of antimicrobial activity of NZ2114 and determine which pharmacokinetic/pharmacodynamic (PK/PD) index and magnitude best correlated with efficacy. Serum drug levels following administration of three fourfold-escalating single-dose levels of NZ2114 were measured by microbiologic assay. Single-dose time-kill studies following doses of 10, 40, and 160 mg/kg of body weight demonstrated concentration-dependent killing over the dose range (0.5 to 3.7 log(10) CFU/thigh) and prolonged postantibiotic effects (3 to 15 h) against both Staphylococcus aureus and Streptococcus pneumoniae. Mice had 10(6.3) to 10(6.8) CFU/thigh of strains of S. pneumoniae or S. aureus at the start of therapy when treated for 24 h with 0.625 to 160 mg/kg/day of NZ2114 fractionated for 4-, 6-, 12-, and 24-h dosing regimens. Nonlinear regression analysis was used to determine which PK/PD index best correlated with microbiologic efficacy. Efficacies of NZ2114 were similar among the dosing intervals (P = 0.99 to 1.0), and regression with the 24-h area under the concentration-time curve (AUC)/MIC index was strong (R(2), 0.90) for both S. aureus and S. pneumoniae. The maximum concentration of drug in serum/MIC index regression was also strong for S. pneumoniae (R(2), 0.96). Studies to identify the PD target for NZ2114 utilized eight S. pneumoniae and six S. aureus isolates and an every-6-h regimen of drug (0.156 to 160 mg/kg/day). Treatment against S. pneumoniae required approximately twofold-less drug for efficacy in relationship to the MIC than did treatment against S. aureus. The free drug 24-h AUCs/MICs necessary to produce a stasis effect were 12.3 +/- 6.7 and 28.5 +/- 11.1 for S. pneumoniae and S. aureus, respectively. The 24-h AUC/MIC associated with a 1-log killing endpoint was only 1.6-fold greater than that needed for stasis. Resistance to other antimicrobial classes did not impact the magnitude of the PD target required for efficacy. The PD target in this model should be considered in the design of clinical trials with this novel antibiotic.

Archaeological analysis of Roman glass excavated from Zadar, Croatia, by a newly developed portable XRF spectrometer for glass

AbstractA newly developed portable x‐ray fluorescence spectrometer has been evaluated through the onsite and nondestructive analyses of 109 Roman glass artifacts excavated at a Roman cemetery found in Zadar, Croatia. The spectrometer has been designed for on‐site analysis of archaeological glass objects. The instrument consists of an x‐ray tube with a Pd target operated at up to 40 kV, silicon drift detector (SDD) with a polymer window, and an enlargeable vacuum sampling chamber. With this system, quantitative analysis of the light elements such as Na and Mg that are important components of glass, as well as heavy trace elements, was successfully carried out. The obtained results evidenced the use of Natron as fluxing agent with alkali contents of 14–22 wt% Na2O, 0.5 wt% MgO and 1.2 wt% Al2O3. In addition, it was found that the differences in the use of Mn and/or Sb as decolorizing agent in colorless bell‐shaped flasks collected from 10 different localities along the coast of Croatia comparing with the same type flasks excavated from Zadar. Copyright © 2009 John Wiley & Sons, Ltd.

Effect of Electrical Properties of Platinum Palladium Oxide Thin Films on the Optical Properties

Pt1-xPdxO thin films were prepared by rf reactive co-sputtering of Pt and Pd target to obtain high quality PtO thin films. To reveal the effect of free carrier absorption caused by high carrier concentration in PtO thin films, its electrical properties and optical properties were measured and analyzed. In the result, quantities of absorption coefficient in visible to near ultraviolet light region were different between PtO films because of the difference of each carrier concentration. Despite this, these absorption coefficients become nearly the same quantities when subtraction of free-carrier absorption was applied. The effect of free carrier absorption decreases with increase of composition of PdO.

Cdk4/6 Inhibitor PD 0332991 Demonstrates Cell Cycle Inhibition Via FLT-PET Imaging and Tissue Analysis in Patients with Recurrent Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) carries an unfavorable prognosis and requires new treatment strategies. The associated t(11;14) chromosomal translocation results in enhanced cyclin D1 expression and cyclin D-dependent kinase (Cdk) activity to promote cell cycle progression. PD 0332991, a specific, potent Cdk4/6 inhibitor causes G1 arrest in MCL cell lines by blocking Cdk4/6-specific phosphorylation of Rb on serine 807–811 (pSRb). We report a translational evaluation of PD 0332991 in MCL patients. A phase Ib, multicenter trial is exploring safety and pharmacodynamic effects of PD 0332991 via 18F-labeled fluorodeoxyglucose (FDG) and fluorothymidine (FLT) positron emission tomography (PET) imaging and pSRb/cell cycle biomarker analyses pre-treatment and on day 21. The maximum standardized uptake value (SUVmax) was calculated in up to 10 lesions per patient and the summed SUVmax of all lesions calculated for each patient. Enrollment has been completed as planned with 16 patients receiving PD 0332991 125 mg orally once daily, 21 of every 28 days. Mean age was 66 years (range [r], 40–80), 81% were male, 70% had stage IV disease, with a median of 3 prior regimens (r, 1–8). Currently there are 8 patients with stable disease and ongoing treatment up to 40 weeks, while 8 patients have progressed. Correlative studies have been extensively employed to demonstrate proof of mechanism. Of 10 patients evaluable for PET analyses, mean change in SUVmax for FLT-PET and FDG-PET was −54.0% (r, −3.0 to −80.4%) and −23.9% (r, 7.6 to −73.3%), respectively.Among five pre- and post-treatment biopsy samples analyzed, marked reductions of 52–100% in the percentage of pSRb were noted in day 21 biopsies (p=0.011); in contrast total Rb was maintained or was reduced by a much lesser degree than pSRb (n=5; p=0.109). Additionally, among a total of eight paired samples, six demonstrated reductions in Ki67 staining post-treatment (r, 48–97%, including the five samples with reduced pSRb staining). Two additional paired samples did not demonstrate reduced Ki67 staining post-treatment. Nonetheless, the overall reduction in Ki67 post-treatment among the eight samples reached statistical significance (p=0.036). In 7/8 of cases, the degree of Ki67 reduction post-treatment correlated with the reduction in FLT-PET SUVmax (R2 = 0.62). Principal toxicities that have been observed thus far include grade 3/4 events of neutropenia and grade 3 thrombocytopenia. In patients with MCL, PD 0332991 is well tolerated with manageable toxicities. Collectively these data demonstrate that PD 0332991 inhibits Cdk4/6, leading to reduced cell proliferation (reflected in reductions in FLT-PET SUVmax, Ki 67 status and pSRb/cell cycle biomarker analyses). As Cdk4 and Cdk6 are direct and specific targets of PD 0332991, these data provide proof of mechanism of action of PD 0332991 in patients by using cyclin D1 dependent MCL as a disease model and inform combination treatment approaches.Research Funding: Supported in part by a grant from the Lymphoma Research Foundation.

Meropenem Pharmacokinetics, Pharmacodynamics, and Monte Carlo Simulation in the Neonate

Hospitalized neonates are exposed to antibiotic-resistant bacterial pathogens and develop nosocomial infections. Limited data are available regarding the neonatal pharmacokinetics of meropenem, a broad spectrum carbapenem antibiotic. Neonates <2 months of age received a single dose of meropenem at 10 or 20 mg/kg. Meropenem serum concentrations were measured at specified times during the 24 hours postinfusion. Population pharmacokinetics (PPK) were evaluated using NONMEM. Using Monte Carlo simulation (MCS), the probability of pharmacokinetic-pharmacodynamic target attainment was evaluated by computer modeling from predictions extrapolated from PPK data, using "virtual" dosing regimens of 10, 20, and 40 mg/kg administered every 8 or 12 hours against community- and hospital-acquired pathogens. Thirty-seven neonates were enrolled, 22 were born at <36 weeks (range, 23-41 weeks) gestational age. Meropenem clearance was greater in neonates with older chronologic ages and in those born at later gestational ages. Serum creatinine and postconceptional age (PCA) were the best overall predictors of meropenem elimination: CL (L/h/kg) = 0.041 + 0.040/SCr + 0.003 x (PCA-35). MCS demonstrated that in infants during the first 2 weeks of life, a dosage of 20 mg/kg/dose every 8 hours achieved the desired PD target in 95% of preterm neonates and 91% of term neonates against Pseudomonas aeruginosa isolated from patients managed in adult and pediatric intensive care units in the United States. MCS based on PPK determinations demonstrated that a meropenem dose of 20 mg/kg every 8 hours should provide adequate therapy for most nosocomial Gram-negative pathogens.

A novel [109Pd] palladium labeled porphyrin for possible use in targeted radiotherapy

The preferential accumulation of porphyrins in malignant tumor cells has been adequately documented. Hence, porphyrin derivatives radiolabeled with a suitable therapeutic radionuclide could be envisaged as potential agents for targeted tumor radiotherapy. Working in this direction, we have radiolabeled a porphyrin derivative, namely, 5,10,15,20-tetrakis[3,4-bis(carboethoxymethyleneoxy)phenyl]-porphyrin, synthesized in-house, with 109Pd [E β(max)=1.12 MeV, E γ=88 keV 3.6(%), T 1/2 = 13.7 h]. The envisaged rationale towards designing of this agent is based on the assumption that 109Pd would complex with the tetrapyrrole donor array constituting the porphyrin core, thereby providing a highly stable chelated complex, and the peripheral ester groups would impart optimum lipophilicity needed for sufficiently high tumor accumulation and retention therein. 109Pd was produced with a specific activity of ∼1.85 GBq/mg and radionuclidic purity of 100% by the thermal neutron bombardment of enriched (98% in 108Pd) metallic Pd target at a flux of 3×1013 n/cm2s1 for 3 d. The porphyrin derivative was synthesized by a multi-step reaction and characterized by normal spectroscopic techniques. 109Pd complex of the synthesized porphyrin derivative was prepared with excellent radiochemical purity (&gt;98%) and the complex was observed to be stable upto 24 h at room temperature. Biodistribution studies carried out in Swiss mice bearing fibrosarcoma tumors revealed good tumor uptake [(5.28±1.46)% injected activity (IA)/g] within 30 min post-injection (p.i.). The complex exhibited favorable tumor/blood and tumor/muscle ratios [1.69±0.23 and 5.00±1.54, respectively at 3 h p.i.], albeit with high liver uptake throughout the time of study (&gt;20% IA).

Pulsed-laser deposition of nanostructured Pd/C thin films: A new entry into metal-supported catalysts for hydrogen producing reactions

Carbon-supported palladium thin films were synthesized at room temperature by KrF excimer pulsed laser deposition by using oriented pyrolytic graphite and Pd target. By changing the experimental conditions, a range of structures, from smooth to porous cluster-assembled carbon films were obtained prior to deposition of the Pd films. High amount of sp 2 coordinated graphitic carbon embedded with large degree of disorder is observed in these carbon films. Surface morphology was studied by using scanning electron microscopy, while compositional analysis was performed by using energy dispersive spectroscopy. Structural analysis was performed using Raman spectroscopy and Fourier transform infrared spectroscopy. The importance of morphology and chemical structure of carbon films on their catalytic activity was investigated by using the hydrolysis of aqueous NaBH 4 as a reference process. Pd/C film produced by pulsed laser deposition are here demonstrated to be a better catalyst than Pd/C powder because of the high content of sp 2 bonding carbon atoms arranged into the porous and irregular surface of the carbon film.

Effect of overlayer thickness on hydrogen permeation of [formula omitted] composite membranes

In this paper, Pd 60 Cu 40 / V – 15 Ni composite membranes were prepared by DC co-sputtering method, and the effect of the Pd 60 Cu 40 overlayer thickness on hydrogen permeability of the Pd 60 Cu 40 / V – 15 Ni composite membrane was studied in the temperature range of 423–673 K. The depositing rate for the overlayer was about 3.5 nm s - 1 when the sputtering voltage of the Cu target and Pd target were set at 395 and 340 V, respectively, four composite membranes with different overlayer thicknesses that corresponded to deposition durations of 30, 60, 90 and 120 s, respectively, were measured under pure hydrogen atmosphere. The composite membrane with the overlayer thickness corresponding to the 60 s deposition duration, showed the highest hydrogen permeability compared to those with the other thicknesses, and its maximum hydrogen permeability of 3.72 × 10 - 8 molH 2 m - 1 s - 1 Pa - 1 / 2 was obtained at 573 K. Hydrogen permeation kinetics of the composite membranes was mainly limited by bulk diffusion at temperature higher than 473 K. When the temperature was lower than 473 K, the hydrogen permeation flux saturated at high upstream H 2 pressures, surface-related reaction should be responsible for the flux saturation at low temperature.

In Vitro and In Vivo Activities of PD 0305970 and PD 0326448, New Bacterial Gyrase/Topoisomerase Inhibitors with Potent Antibacterial Activities versus Multidrug-Resistant Gram-Positive and Fastidious Organism Groups

PD 0305970 and PD 0326448 are new bacterial gyrase and topoisomerase inhibitors (quinazoline-2,4-diones) that possess outstanding in vitro and in vivo activities against a wide spectrum of bacterial species including quinolone- and multidrug-resistant gram-positive and fastidious organism groups. The respective MICs (microg/ml) for PD 0305970 capable of inhibiting>or=90% of bacterial strains tested ranged from 0.125 to 0.5 versus staphylococci, 0.03 to 0.06 versus streptococci, 0.25 to 2 versus enterococci, and 0.25 to 0.5 versus Moraxella catarrhalis, Haemophilus influenzae, Listeria monocytogenes, Legionella pneumophila, and Neisseria spp. PD 0326448 MIC90s were generally twofold higher versus these same organism groups. Comparative quinolone MIC90 values were 4- to 512-fold higher than those of PD 0305970. In testing for frequency of resistance, PD 0305970 and levofloxacin showed low levels of development of spontaneous resistant mutants versus both Staphylococcus aureus and Streptococcus pneumoniae. Unlike quinolones, which target primarily gyrA and parC, analysis of resistant mutants in S. pneumoniae indicates that the likely targets of PD 0305970 are gyrB and parE. PD 0305970 demonstrated rapid bactericidal activity by in vitro time-kill testing versus streptococci. This bactericidal activity carried over to in vivo testing, where PD 0305970 and PD 0326448 displayed outstanding Streptococcus pyogenes 50% protective doses (PD50s) (oral dosing) of 0.7 and 3.6 mg/kg, respectively (ciprofloxacin and levofloxacin PD50s were>100 and 17.7 mg/kg, respectively). PD 0305970 was also potent in a pneumococcal pneumonia mouse infection model (PD50=3.2 mg/kg) and was 22-fold more potent than levofloxacin.

Preparation and characterization of Pd–Cu/V–15Ni composite membrane for hydrogen permeation

Pd 100− x Cu x /V–15Ni composite membranes ( x = 0, 20, 30, 40, 50, 60 wt.%) were deposited for the first time by co-sputtering in this paper. XRD, SEM and AES were performed to characterize the composite membrane, and its deposition conditions were studied and optimized. Cu concentration of the Pd–Cu overlayer shows a linear dependence on the Cu target sputtering voltage, and it can be expressed as: x Cu (wt.%) = 0.45 V Cu − 138 (where V Pd = 340 V, and V Cu > 300 V). SEM observation shows that the overlayer films have very dense and fine microstructure; the depositing rate is about 3.5 nm/s when the Pd and Cu target voltages are set as 340 and 395 V, respectively. The Pd 100− x Cu x ( x = 0–60 wt.%) nano-overlayer presents a continuous fcc solid solution structure at room temperature, and the variation of its lattice spacing with Cu content agrees well with the Vegard's law. The obtained Pd 60Cu 40/V–15Ni composite membrane shows higher hydrogen permeability than that of Pd 60Cu 40 alloy membrane and presents good feasibility to replace the Pd 60Cu 40 alloy membrane for hydrogen purification in the temperature range of 423–673 K.

Simulations of a grazing-incidence pumped x-ray laser at14.7nm

Numerical simulations of the grazing-incidence pumped Ni-like Pd x-ray laser at $14.7\phantom{\rule{0.3em}{0ex}}\mathrm{nm}$ ($4d\ensuremath{\rightarrow}4p$, $J=0\ensuremath{\rightarrow}1$) is performed using a modified one-dimensional hydrodynamic code MEDUSA. The effective absorption of the main laser pulse in the gain region is greatly increased due to the lengthened propagation path. Results predict that a saturated output of the x-ray laser can be achieved with only subjoules driver energy on a $4\text{\ensuremath{-}}\mathrm{mm}$-long Pd target.

Tarnishing resistance of silver–palladium thin films

Ag–Pd decorative coatings are supposed to provide better tarnishing resistance as compared to pure Ag, while keeping good optical (brightness) and mechanical properties (ductility). Palladium has a similar optical appearance as silver, and forms a thin protective oxide surface layer. Thus, a small incorporation of Pd in Ag could improve its tarnishing resistance. Thin Ag–Pd films were deposited by magnetron co-sputtering from Pd and Ag targets. The Ar gas pressure, target power and substrate temperature were varied to modify the chemical composition of the films and optimise their properties. The optical properties of the films were evaluated by spectroscopic ellipsometry and colorimetry. Increasing Ar gas pressure and substrate temperature results in a drastic decrease of the specular reflectivity of the films. At constant deposition conditions the reflectivity of the Ag–Pd films decreases with increasing Pd content. The film hardness, evaluated by nanoindentation, increases with Pd content. The tarnishing resistance of the films was evaluated by sulphidation tests. The colour change of the films due to the sulphidation was measured by colorimetry. The nature of chemical bonds of the tarnished products was evidenced by XPS. The results suggest an improvement of tarnishing resistance of the Ag–Pd films with increasing Pd content.

Stress Evolution in Sputter-deposited Fe–Pd Shape-memory Thin Films

Fe–Pd films with Pd content varying between 26 and 30 at.% have been deposited by means of magnetron sputtering of elemental Fe and Pd targets. As-deposited films are highly supersaturated solid solutions of Pd in Fe that have a body-centered-cubic crystal structure and a very fine grain size. Substrate curvature measurements indicate that the films undergo an irreversible densification when heated above 100 °C. This densification is attributed to a structural change that is also observed in other supersaturated systems with a substantial atomic size difference between the constituents. It is possible to retain the high-temperature austenite phase at low temperature by annealing the films at 900 °C followed by rapid cooling. Depending on film composition, this metastable austenitic phase transforms to either a body-centered tetragonal (bct) or a face-centered tetragonal (fct) martensite around room temperature. Substrate curvature measurements show that formation of the fct martensite is reversible, while that of bct martensite is not. The fct transformation occurs at lower Pd content and higher temperature than reported for bulk materials. Both the fct and the fcc phase show a strong Invar effect at lower temperature and Pd content than observed in the bulk.

Natural widths of hypersatellite K-X-ray lines and lifetimes of double K-hole states in mid-Z atoms

K-X-ray spectra of Zr, Nb, Mo and Pd targets bombarded with 250MeV carbon and 360MeV oxygen ions are studied with high resolution diffraction spectrometry. Relative yields and natural widths of the Khα1,2 hypersatellite lines are determined and compared with those of the diagram lines. The widths of Khα1,2 lines are compared with the new phenomenological formula which takes into account the retardation of the Khα1 transition in the LS coupling scheme. The data significantly exceed the expected values. Deduced lifetimes of the double K-hole states are shorter than expected.

Preparation of palladium–silver alloy films by a dual-sputtering technique and its application in hydrogen separation membrane

Submicron thick palladium–silver alloy films with 23 wt.% of silver (Pd–Ag23) have been synthesized by simultaneous sputtering from pure targets of Pd and Ag. Full characterization of the deposited films was performed by using X-ray photoelectron spectroscopy, high-resolution scanning electron microscopy, high-resolution transmission electron microscopy, and X-ray diffraction. The analytical results revealed that the deposited Pd–Ag alloy had a Ag content of about 21–22 wt.%, very close to and within measurement error of the expected Ag content of 23 wt.%. The as-deposited Pd–Ag alloy had a fine microstructure. The characterized Pd–Ag alloy films were then deposited on a supporting microsieve to form Pd–Ag membranes for hydrogen separation. The submicron thick Pd–Ag membranes obtained high separation fluxes up to 4 mol H 2/m 2 s with a selectivity higher than 1500 for hydrogen over helium.

Assessment of pharmacokinetic–pharmacodynamic target attainment of gemifloxacin against Streptococcus pneumoniae

The treatment of community-acquired respiratory tract infections has been complicated by the emergence of multidrug-resistant Streptococcus pneumoniae. Although traditionally rare, a growing concern for fluoroquinolone-resistant pneumococci has surfaced. More pharmacodynamically potent antimicrobial agents are clearly needed, as the use of such agents may further optimize clinical and microbiological outcomes for patients and slow the emergence of fluoroquinolone resistance. For fluoroquinolones, the ratio of the 24-h area under the concentration–time curve of the agent to the minimum inhibitory concentration of the agent against the pathogen for the fraction of unbound drug is the major pharmacokinetic–pharmacodynamic (PK–PD) measure correlating with efficacy in nonclinical models and infected patients. A 2500-patient Monte Carlo simulation, utilizing a patient–population pharmacokinetic model derived from phase 3 registration trials and the minimum inhibitory concentration distribution for gemifloxacin against 3117 clinical strains of S. pneumoniae, was carried out to estimate the probability of gemifloxacin attaining exposures associated with efficacy. The overall probability PK–PD target attainment for gemifloxacin was greater than 0.99. Gemifloxacin is among the most pharmacodynamically potent fluoroquinolones and is more potent than ciprofloxacin, ofloxacin, and levofloxacin. Preferential use of pharmacodynamically potent agents over other alternatives may lead to improved clinical outcomes and decreased selection of fluoroquinolone-resistant pneumococci.

Hydrogen sensor based on optical and electrical switching

We report about a hydrogen sensor using electrical and optical switching properties of Pd-based thin films. Palladium is well known for its ability to absorb high amounts of hydrogen due to palladium hydride formation. Series of different thickness Pd films (10–70 nm) were deposited on glass substrates by dc plasma sputtering. A CaF 2 buffer layer was deposited between the glass support and the Pd-film in order to reduce the internal stresses and improve the mechanical stability of the sensor. A Pt diffusion barrier was deposited on the active film to prevent sensor poisoning. Pd-polymer nano-composite films were deposited by co-sputtering of Pd and polymer targets. The morphology and composition of the films were analysed by SEM, TEM and EDS. Electrical resistance and differential transmittance were measured depending on different concentrations and flows of the testing gas (0.5–10.0% hydrogen in nitrogen). A proportional dependence of the measured signal on the hydrogen concentration was found. The influence of different structures and morphologies on the switching properties was investigated.

Microfabrication of palladium-silver alloy membranes for hydrogen separation

A process for the microfabrication of a wafer-scale palladium-silver alloy membrane (Pd-Ag) is presented. Pd-Ag alloy films containing 23 wt% Ag were prepared by co-sputtering from pure Pd and Ag targets. The films were deposited on the unetched side of a <110>-oriented silicon wafer in which deep grooves were etched in a concentrated KOH solution, leaving silicon membranes with a thickness of ca. 50 μm. After alloy deposition, the silicon membranes were removed by etching, leaving Pd-Ag membranes. Anodic bonding of thick glass plates (containing powder blasted flow channels) to both sides of the silicon substrate was used to package the membranes and create a robust module. The hydrogen permeability of the Pd-Ag membranes was determined to be typically 0.5 mol H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /spl middot/s with a minimal selectivity of 550 for H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> with respect to He. The mechanical strength of the membrane was found to be adequate, pressures of up to 4 bars at room temperature did not break the membrane. The results indicate that the membranes are suitable for application in hydrogen purification or in dehydrogenation reactors. The presented fabrication method allows the development of a module for industrial applications that consists of a stack of a large number of glass/membrane plates.

Hydrogen permeation characteristics of V-15Ni membrane with Pd/Ag overlayer by sputtering

Pd–Ag alloy coated V-15Ni composite membranes were prepared by co-sputtering of separate pure Pd and Ag targets using a DC multi-target sputtering system where voltage for each target can be controlled independently. The film composition was controlled by changing the target voltage. Hydrogen permeation characteristics of as-prepared composite membranes were investigated using the gas permeation technique in the temperature range of 423–673 K. The hydrogen permeation of the composite membranes was mainly bulk-diffusion limited at a temperature higher than 473 K. At 473 K or lower, the hydrogen permeability of the composite membranes increased with the Ag content until 30 at%.