Sample records for platinum compounds tested

  1. Toxicity of platinum compounds. (United States)

    Hartmann, Jörg Thomas; Lipp, Hans-Peter


    Since the introduction of platinum-based combination chemotherapy, particularly cisplatin, the outcome of the treatment of many solid tumours has changed. The leading platinum compounds in cancer chemotherapy are cisplatin, carboplatin and oxaliplatin. They share some structural similarities; however, there are marked differences between them in therapeutic use, pharmacokinetics and adverse effects profiles [1-4]. Compared to cisplatin, carboplatin has inferior efficacy in germ-cell tumour, head and neck cancer and bladder and oesophageal carcinoma, whereas both drugs seem to have comparable efficacy in advanced non-small cell and small cell lung cancer as well as ovarian cancer [5-7]. Oxaliplatin belongs to the group of diaminocyclohexane platinum compounds. It is the first platinum-based drug that has marked efficacy in colorectal cancer when given in combination with 5-fluorouracil and folinic acid [8,9]. Other platinum compounds such as oral JM216, ZD0473, BBR3464 and SPI-77, which is a pegylated liposomal formulation of cisplatin, are still under investigation [10-13], whereas nedaplatin has been approved in Japan for the treatment of non-small cell lung cancer and other solid tumours. This review focuses on cisplatin, carboplatin and oxaliplatin.

  2. Highly trifluoromethylated platinum compounds. (United States)

    Martínez-Salvador, Sonia; Forniés, Juan; Martín, Antonio; Menjón, Babil


    The homoleptic, square-planar organoplatinum(II) compound [NBu(4)](2) [Pt(CF(3))(4)] (1) undergoes oxidative addition of CF(3) I under mild conditions to give rise to the octahedral organoplatinum(IV) complex [NBu(4)](2) [Pt(CF(3))(5)I] (2). This highly trifluoromethylated species reacts with Ag(+) salts of weakly coordinating anions in Me(2)CO under a wet-air stream to afford the aquo derivative [NBu(4)][Pt(CF(3))(5) (OH(2))] (4) in around 75% yield. When the reaction of 2 with the same Ag(+) salts is carried out in MeCN, the solvento compound [NBu(4) ][Pt(CF(3))(5)(NCMe)] (5) is obtained in around 80% yield. The aquo ligand in 4 as well as the MeCN ligand in 5 are labile and can be cleanly replaced by neutral and anionic ligands to furnish a series of pentakis(trifluoromethyl)platinate(IV) compounds with formulae [NBu(4)][Pt(CF(3))(5) (L)] (L=CO (6), pyridine (py; 7), tetrahydrothiophene (tht; 8)) and [NBu(4)](2) [Pt(CF(3))(5)X] (X=Cl (9), Br (10)). The unusual carbonyl-platinum(IV) derivative [NBu(4)][Pt(CF(3))(5) (CO)] (6) is thermally stable and has a ν(CO) of 2194 cm(-1). The crystal structures of 2⋅CH(2)Cl(2), 5, [PPh(4) ][Pt(CF(3))(5)(CO)] (6'), and 7 have been established by X-ray diffraction methods. Compound 2 has shown itself to be a convenient entry to the chemistry of highly trifluoromethylated platinum compounds. To the best of our knowledge, compounds 2 and 4-10 are the organoelement compounds with the highest CF(3) content to have been isolated and adequately characterized to date.

  3. Platinum compounds with anti-tumour activity

    NARCIS (Netherlands)

    Plooy, A.C.M.; Lohman, P.H.M.


    Ten platinum (Pt) coordination complexes with different ligands, comprising both Pt(II) and Pt(IV) complexes of which the cis-compounds all possessed at least some anti-tumour activity and the trans-compounds were inactive, were tested as to their effect on cell survival and the induction and repair

  4. [Platinum compounds: metabolism, toxicity and supportive strategies]. (United States)

    Lipp, H P; Hartmann, J T


    Although the leading platinum compounds, cisplatin, carboplatin, and oxaliplatin, share some structural similarities, there are marked differences between them in therapeutic uses, pharmacokinetics, and adverse effects profiles. Compared with cisplatin, carboplatin has inferior efficacy in germ-cell tumors, head and neck cancers, and bladder and esophageal carcinomas, whereas the two drugs appear to have comparable efficacy in ovarian cancer, extensive small-cell lung cancers (SCLC), and advanced non-small-cell lung cancers (NSCLC). Oxaliplatin belongs to the group of diaminocyclohexane (DACH) platinum compounds. It is the first platinum-based drug that has marked efficacy in colorectal cancer when given in combination with 5-fluorouracil and folinic acid. Nedaplatin has been registered in Japan, whereas other derivatives, like JM216 (which is the only orally available platinum derivative), ZD0473, BBR3464, and SPI-77 (a liposomal formulation of cisplatin), are still under investigation. The adverse effects of platinum compounds are reviewed together with possible prevention strategies.

  5. Targeting Platinum Compounds: synthesis and biological activity


    VAN ZUTPHEN, Steven


    Inspired by cisplatin, the inorganic drug discovered by Barnett Rosenberg in 1965, the research described in this thesis uses targeting ligands, or ligands varied in a combinatorial fashion, to find platinum complexes with more specific modes of action. These studies have lead to the development of novel (solid-phase) synthetic methods and to the discovery of several compounds with promising biological properties.

  6. Request for Correction 11001 Toxicological Review of Halogenated Platinum Salts and Platinum Compounds (United States)

    Request for Correction by the International Platinum Group Metals Association seeking the correction of information disseminated in the draft EPA document Toxicological Review of Halogenated Platinum Salts and Platinum Compounds: In Support of Summary Information on the Integrated Risk Information System (IRIS).

  7. Targeting Platinum Compounds : synthesis and biological activity

    NARCIS (Netherlands)

    Zutphen, Steven van


    Inspired by cisplatin, the inorganic drug discovered by Barnett Rosenberg in 1965, the research described in this thesis uses targeting ligands, or ligands varied in a combinatorial fashion, to find platinum complexes with more specific modes of action. These studies have lead to the development of

  8. Innovative use of platinum compounds to selectively detect live microorganisms by polymerase chain reaction. (United States)

    Soejima, Takashi; Minami, Jun-Ichi; Xiao, Jin-Zhong; Abe, Fumiaki


    PCR cannot distinguish live microorganisms from dead ones. To circumvent this disadvantage, ethidium/propidium-monoazide (EMA/PMA) and psoralen to discriminate live from dead bacteria have been used for 2 decades. These methods require the use of numerous laborious procedures. We introduce an innovative method that uses platinum compounds, which are primarily used as catalysts in organic chemistry and partly used as anti-cancer drugs. Microorganisms are briefly exposed to platinum compounds in vivo, and these compounds penetrate dead (compromised) microorganisms but not live ones and are chelated by chromosomal DNA. The use of platinum compounds permits clear discrimination between live and dead microorganisms in water and milk (including Cronobacter sakazakii and Escherichia coli) via PCR compared with typically used PMA. This platinum-PCR method could enable the specific detection of viable coliforms in milk at a concentration of 5-10 CFU mL(-1) specified by EU/USA regulations after a 4-h process. For sample components, environmental water contains lower levels of PCR inhibitors than milk does, and milk is similar to infant formula, skim milk and blood; thus, the use of the platinum-PCR method could also prevent food poisoning due to the presence of C. sakazakii in dairy products. This method could provide outstanding rapidity for use in environmental/food/clinical tests. Platinum-PCR could also be a substitute for the typical culture-based methods currently used.

  9. Behavior of platinum(iv) complexes in models of tumor hypoxia: cytotoxicity, compound distribution and accumulation. (United States)

    Schreiber-Brynzak, Ekaterina; Pichler, Verena; Heffeter, Petra; Hanson, Buck; Theiner, Sarah; Lichtscheidl-Schultz, Irene; Kornauth, Christoph; Bamonti, Luca; Dhery, Vineet; Groza, Diana; Berry, David; Berger, Walter; Galanski, Markus; Jakupec, Michael A; Keppler, Bernhard K


    Hypoxia in solid tumors remains a challenge for conventional cancer therapeutics. As a source for resistance, metastasis development and drug bioprocessing, it influences treatment results and disease outcome. Bioreductive platinum(iv) prodrugs might be advantageous over conventional metal-based therapeutics, as biotransformation in a reductive milieu, such as under hypoxia, is required for drug activation. This study deals with a two-step screening of experimental platinum(iv) prodrugs with different rates of reduction and lipophilicity with the aim of identifying the most appropriate compounds for further investigations. In the first step, the cytotoxicity of all compounds was compared in hypoxic multicellular spheroids and monolayer culture using a set of cancer cell lines with different sensitivities to platinum(ii) compounds. Secondly, two selected compounds were tested in hypoxic xenografts in SCID mouse models in comparison to satraplatin, and, additionally, (LA)-ICP-MS-based accumulation and distribution studies were performed for these compounds in hypoxic spheroids and xenografts. Our findings suggest that, while cellular uptake and cytotoxicity strongly correlate with lipophilicity, cytotoxicity under hypoxia compared to non-hypoxic conditions and antitumor activity of platinum(iv) prodrugs are dependent on their rate of reduction.

  10. Concomitant treatment of F98 glioma cells with new liposomal platinum compounds and ionizing radiation. (United States)

    Charest, Gabriel; Paquette, Benoit; Fortin, David; Mathieu, David; Sanche, Léon


    Despite significant advances, the radiotherapy and chemotherapy protocols marginally improve the overall survival of patients with glioblastoma. Lipoplatin(TM), and Lipoxal(TM), the liposomal formulations of cisplatin and oxaliplatin respectively, were tested on the F98 glioma cells for their ability to improve the cell uptake and increase the synergic effect when combined with ionizing radiation. The cytotoxicity and synergic effect of platinum compounds were assessed by colony formation assay, while the cellular uptake was measured by Inductively Coupled Plasma Mass Spectrometer (ICP-MS). After 4 h exposure with platinum compounds, cells were irradiated (1.5-6.6 Gy) with a (60)Co source. The liposomal formulations were compared to their liposome-free analogs and to carboplatin. The concomitant treatment of F98 cells with carboplatin and radiation produced the highest radiosensitizing effect (30-fold increase). Among the platinum compounds tested, Lipoplatin(TM) produced the most promising results. This liposomal formulation of cisplatin improved the cell uptake by 3-fold, and its radiosensitizing potential was enhanced by 14-fold. Although Lipoxal(TM) can potentially reduce the adverse effect of oxaliplatin, a synergic effect with radiation was measured only when incubated at a concentration higher than its IC50. Conversely, concomitant treatment with cisplatin did not result in a synergic effect, as in fact a radioprotective effect was measured on the F98 cells. In conclusion, among the five platinum compounds tested, carboplatin and Lipoplatin(TM) showed the best radiosensitizing effect. Lipoplatin(TM) seems the most promising since it led to the best cellular incorporation and has already been reported to be less neurotoxic than other platinum compounds.

  11. Concomitant treatment of F98 glioma cells with new liposomal platinum compounds and ionizing radiation


    Charest, Gabriel; Paquette, Benoit; Fortin, David; Mathieu, David; Sanche, Léon


    Despite significant advances, the radiotherapy and chemotherapy protocols marginally improve the overall survival of patients with glioblastoma. Lipoplatin™, and Lipoxal™, the liposomal formulations of cisplatin and oxaliplatin respectively, were tested on the F98 glioma cells for their ability to improve the cell uptake and increase the synergic effect when combined with ionizing radiation. The cytotoxicity and synergic effect of platinum compounds were assessed by colony formation assay, wh...

  12. Developing Central Nervous System and Vulnerability to Platinum Compounds

    Directory of Open Access Journals (Sweden)

    G. Bernocchi


    Full Text Available Comparative studies on the effects of the platinum complexes in use or in clinical trials are carried out in order to discover differences in the neurotoxic potential and the reversibility of neurotoxicity. In this paper, we summarized the current literature on neurotoxicity and chemoresistance of cisplatin (cisPt and discussed our recent efforts on the interference of cisPt and a new platinum compound [Pt(O,O′-acac(γ-acac(DMS] (PtAcacDMS, with high specific reactivity with sulphur ligands instead of nucleobases as cisPt, on some crucial events of rat postnatal cerebellum development. The acute effects of drug treatments on cell proliferation and death in the external granular layer and granule cell migration and the late effects on the dendrite growth of Purkinje cells were evaluated. Together with the demonstrated antineoplastic effectiveness in vitro, compared with cisPt, data suggest a lower neurotoxicity of PtAcacDMS, in spite of its presence in the brain that involves considerations on the blood brain barrier permeability.

  13. Novel platinum(II) compounds with O,S bidentate ligands: synthesis, characterization, antiproliferative properties and biomolecular interactions. (United States)

    Mügge, Carolin; Liu, Ruiqi; Görls, Helmar; Gabbiani, Chiara; Michelucci, Elena; Rüdiger, Nadine; Clement, Joachim H; Messori, Luigi; Weigand, Wolfgang


    Cisplatin and its analogues are first-line chemotherapeutic agents for the treatment of numerous human cancers. A major inconvenience in their clinical use is their strong tendency to link to sulfur compounds, especially in kidney, ultimately leading to severe nephrotoxicity. To overcome this drawback we prepared a variety of platinum complexes with sulfur ligands and analyzed their biological profiles. Here, a series of six platinum(II) compounds bearing a conserved O,S binding moiety have been synthesized and characterized as experimental anticancer agents. The six compounds differ in the nature of the O,S bidentate β-hydroxydithiocinnamic alkyl ester ligand where both the substituents on the aromatic ring and the length of the alkyl chain may be varied. The two remaining coordination positions at the square-planar platinum(II) center are occupied by a chloride ion and a DMSO molecule. These novel platinum compounds showed an acceptable solubility profile in mixed DMSO-buffer solutions and an appreciable stability at physiological pH as judged from analysis of their time-course UV-visible absorption spectra. Their anti-proliferative and pro-apoptotic activities were tested against the cisplatin-resistant lung cancer cell line A549. Assays revealed significant effects of the sample drugs at low concentrations (in the μmolar range); initial structure-activity-relationships are proposed. The activity of the apoptosis-promoting protein caspase 3/7 was determined; results proved that these novel platinum compounds, under the chosen experimental conditions, preferentially induce apoptosis over necrosis. Reactions with the model proteins cytochrome c, lysozyme and albumin were studied by ESI MS and ICP-OES to gain preliminary mechanistic information. The tested compounds turned out to metalate the mentioned proteins to a large extent. In view of the obtained results these novel platinum complexes qualify themselves as promising cytotoxic agents and merit, in our

  14. The role of macrocyclic compounds in the extraction and possible separation of platinum and rhodium from chloride solutions (United States)

    Jyothi, Rajesh Kumar; Lee, Jin-Young


    Macrocyclic compounds (crown ethers), specifically 18-crown-6 (18-C-6), benzo-15-crown-5 (B-15-C-5), di-benzo-18-crown-6 (DB-18-C-6) and di-cyclohexano-18-crown-6 (DC-18C-6), are used as extractants as well as synergists with amine-group extractants. Platinum and rhodium belong to platinum-group metals (PGMs) and have very similar ionic radii and similar properties. The separation of PGMs is most useful for the preparation of functional materials. Macrocyclic compounds are tested for platinum and rhodium separation and are found to achieve marginal separation. Amines (used as extractants) are paired with macrocyclic compounds (used as synergists), and the separation factor between platinum and rhodium is increased with synergistic enhancement from a chloride solution. The present study discusses extraction chemistry, separation factors and the synergy between platinum and rhodium from chloride solutions. To ensure accurate data, the aqueous samples in this study are analyzed using an inductively coupled plasma optical emission spectrometer (ICP-OES).

  15. Diffuse X-Ray Scattering from Several Platinum Chain Compounds

    DEFF Research Database (Denmark)

    Braude, A.; Lindegaard-Andersen, Asger; Carneiro, K.


    Values of the Fermi wavevector for several platinum based one-dimensional conductors were determined from diffuse X-ray scattering measurements. The values were compared with those expected from the chemical compositions. The importance of conclusive values of this parameter is stressed and the c......Values of the Fermi wavevector for several platinum based one-dimensional conductors were determined from diffuse X-ray scattering measurements. The values were compared with those expected from the chemical compositions. The importance of conclusive values of this parameter is stressed...


    NARCIS (Netherlands)



    The role of glutathione (GSH) in the effectiveness of and resistance to 7 platinum compounds [5 Pt(II) and 2 Pt(IV) drugs] was evaluated in a 8.6-fold cisplatin (CDDP)-resistant human small cell lung cancer cell line (GLC4/CDDP), the parent GLC4 line, a 3.7-fold CDDP-resistant human embryonal carcin

  17. Diarylplatinum(II Compounds as Versatile Metallating Agents in the Synthesis of Cyclometallated Platinum Compounds with N-Donor Ligands

    Directory of Open Access Journals (Sweden)

    Margarita Crespo


    Full Text Available This review deals with the reactions of diarylplatinum(II complexes with N-donor ligands to produce a variety of cycloplatinated compounds including endo-five-, endo-seven-, endo-six- or exo-five-membered platinacycles. The observed reactions result from a series of oxidative addition/reductive elimination processes taking place at platinum(II/platinum(IV species and involving C–X (X = H, Cl, Br bond activation, arene elimination, and, in some cases, Caryl–Caryl bond formation.

  18. Glioblastoma Treatment: Bypassing the Toxicity of Platinum Compounds by Using Liposomal Formulation and Increasing Treatment Efficiency With Concomitant Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Charest, Gabriel; Sanche, Leon [Center for Research in Radiotherapy, Department of Nuclear Medicine and Radiobiology, Universite de Sherbrooke, Sherbrooke, Quebec (Canada); Fortin, David; Mathieu, David [Department of Surgery, Division of Neurosurgery, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Quebec (Canada); Paquette, Benoit, E-mail: [Center for Research in Radiotherapy, Department of Nuclear Medicine and Radiobiology, Universite de Sherbrooke, Sherbrooke, Quebec (Canada)


    Purpose: Treatments of glioblastoma with cisplatin or oxaliplatin only marginally improve the overall survival of patients and cause important side effects. To prevent adverse effects, improve delivery, and optimize the tumor response to treatment in combination with radiotherapy, a potential approach consists of incorporating the platinum agent in a liposome. Methods and Materials: In this study, cisplatin, oxaliplatin, carboplatin, Lipoplatin (the liposomal formulation of cisplatin), and Lipoxal (the liposomal formulation of oxaliplatin) were tested on F98 glioma orthotopically implanted in Fischer rats. The platinum compounds were administered by intracarotid infusion and were assessed for the ability to reduce toxicity, improve cancer cell uptake, and increase survival of animals when combined or not combined with radiotherapy. Results: The tumor uptake was 2.4-fold more important for Lipoxal than the liposome-free oxaliplatin. Lipoxal also improved the specificity of oxaliplatin as shown by a higher ratio of tumor to right hemisphere uptake. Surprisingly, Lipoplatin led to lower tumor uptake compared with cisplatin. However, Lipoplatin had the advantage of largely reducing the toxicity of cisplatin and allowed us to capitalize on the anticancer activity of this agent. Conclusion: Among the five platinum compounds tested, carboplatin showed the best increase in survival when combined with radiation for treatment of glioma implanted in Fischer rats.

  19. In vitro effects of platinum compounds on renal cellular respiration in mice. (United States)

    Almarzooqi, Saeeda-S; Alfazari, Ali-S; Abdul-Kader, Hidaya-M; Saraswathiamma, Dhanya; Albawardi, Alia-S; Souid, Abdul-Kader


    Cisplatin, carboplatin and oxaliplatin are structurally-related compounds, which are commonly used in cancer therapy. Cisplatin (Platinol(®)) has Boxed Warning stating: "Cumulative renal toxicity associated with PLATINOL is severe", while carboplatin and oxaliplatin are less nephrotoxic. These drugs form platinum adducts with cellular DNA. Their bindings to cellular thiols (e.g., glutathione and metallothionein) are known to contribute to drug resistance while thiol depletion augments platinum toxicity. Using phosphorescence oxygen analyzer, this study investigated the effects of platinum drugs on renal cellular respiration (mitochondrial O2 consumption) in the presence and absence of the thiol blocking agent N-ethylmaleimide (used here as a model for thiol depletion). Renal cellular ATP was also determined. Kidney fragments from C57BL/6 mice were incubated at 37 °C in Krebs-Henseleit buffer (gassed with 95% O2:5% CO2) with and without 100 μM platinum drug in the presence and absence of 100 μM N-ethylmaleimide for ≤ 6 h. Platinum drugs alone had no effects on cellular respiration (P ≥ 0.143) or ATP (P ≥ 0.161). N-ethylmaleimide lowered cellular respiration (P ≤ 0.114) and ATP (P = 0.008). The combination of platinum drug and N-ethylmaleimide significantly lowered both cellular respiration (P ≤ 0.006) and ATP (P ≤ 0.003). Incubations with N-ethylmaleimide alone were associated with moderate-to-severe tubular necrosis. Incubations with cisplatin+N-ethylmaleimide vs. cisplatin alone produced similar severities of tubular necrosis. Tubular derangements were more prominent in carboplatin+N-ethylmaleimide vs. carboplatin alone and in oxaliplatin+N-ethylmaleimide vs. oxaliplatin alone. These results demonstrate the adverse events of thiol depletion on platinum-induced nephrotoxicities. The results suggest cellular bioenergetics is a useful surrogate biomarker for assessing drug-induced nephrotoxicities.

  20. Comparison of PIXE and SXRF for kinetic studies in cell pharmacology of platinum and gold compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, F. (Faculte de Medecine de Creteil (France). Lab. de Biophysique Laboratoire d' Analyse par Activation Pierre-Sue - Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)); Chevallier, P. (Paris-6 Univ., 75 (France)); Tapiero, H. (Hopital Paul-Brousse, 94 - Villejuif (France)); Massiot, P.; Piccot, D. (Laboratoire d' Analyse par Activation Pierre-Sue - Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France)); Galle, P. (Faculte de Medecine de Creteil (France). Lab. de Biophysique); Silvestro, L. (Turin Univ. (Italy). Facolta di Medicina); Arizti, P. (Universidad Pais Vasco, Leioa (Spain). Facultad de Medicina)


    The analytical conditions in PIXE and SXRF are studied in order to optimize the detection of platinum and gold compounds in the cell and in their subcellular fractions. Calibration curves, reproducibility and detection limits were obtained with both techniques and compared. The best detection limit was achieved with SXRF. Preliminary data on the cellular pharmacokinetics of cisplatinum and gold selective distribution in nuclei were obtained by the above techniques. (author).

  1. Platinum compounds sensitize ovarian carcinoma cells to ABT-737 by modulation of the Mcl-1/Noxa axis. (United States)

    Simonin, Karin; N'Diaye, Monique; Lheureux, Stéphanie; Loussouarn, Claire; Dutoit, Soizic; Briand, Mélanie; Giffard, Florence; Brotin, Emilie; Blanc-Fournier, Cécile; Poulain, Laurent


    Ovarian cancer is the leading cause of death from gynecological cancer. The anti-apoptotic protein Bcl-x(L) is frequently overexpressed in ovarian carcinoma which correlates with chemotherapy resistance. It has been demonstrated that Bcl-x(L) cooperates with another anti-apoptotic protein, Mcl-1, to protect ovarian cancer cells against apoptosis, and that their concomitant inhibition induces massive cell death. Here, we examined the interest of ABT-737, a potent BH3-mimetic molecule targeting Bcl-x(L), both alone and in combination with Mcl-1 modulators, in ovarian cancer cell lines. As a single agent, ABT-737 was ineffective at promoting cell death in the four cell lines we tested in vitro. However, the specific inhibition of Mcl-1 by siRNA dramatically increased the sensitivity of chemoresistant cells to ABT-737. Platinum compounds also sensitize to ABT-737 by dose-dependently decreasing Mcl-1 expression or by increasing the expression of pro-apoptotic BH3-only proteins Noxa and, to a lower extent, Bim. Furthermore, we demonstrated that Noxa accumulation was involved in apoptosis occurring in response to the combination of ABT-737 and platinum compounds, since cells were protected from apoptosis by its silencing. Moreover, the combination was also highly cytotoxic ex vivo in sliced SKOV3 tumor nodes. However we observed in these slices a strong basal expression of Noxa and apoptotic cell death in response to ABT-737 alone. Therefore, we have revealed that the modulation of the Mcl-1/Noxa axis by platinum compounds results in a strong sensitization of chemoresistant ovarian carcinoma cells to ABT-737, which could constitute a promising therapeutic in these cancers.

  2. E platinum, a newly synthesized platinum compound, induces apoptosis through ROS-triggered ER stress in gastric carcinoma cells. (United States)

    Wang, Xiaoping; Guo, Qinglong; Tao, Lei; Zhao, Li; Chen, Yan; An, Teng; Chen, Zhen; Fu, Rong


    Gastric cancer (GC) is still one of the leading causes of death in cancer-related diseases. In this study, we aimed to investigate the antitumor effect of E Platinum, a newly platinum-based chemotherapeutic agent bearing the basic structure of Oxaliplatin, in a variety of gastric carcinoma cells and the underlying mechanisms. We demonstrated that E Platinum significantly induced apoptosis in gastric cancer cells via mitochondrial apoptotic pathway as a result of increased reactive oxygen species (ROS). We also found that E Platinum enhanced Ca(2+) flux out from the endoplasmic reticulum by increasing the protein expression of IP3R type 1 (IP3R1) and decreasing the expression of ERp44. Dysfunction of Ca(2+) homeostasis in endoplasmic reticulum (ER) leads to accumulation of unfolded proteins and ER stress. Mechanically, E Platinum increased ER stress associated protein expression such as GRP78, p-PERK, p-eIF2α, ATF4, and CHOP. However, knocking down CHOP reversed E Platinum-induced apoptosis by blocking mitochondrial apoptotic pathway. Furthermore, 10 mg/kg of E Platinum significantly suppressed BGC-823 tumor growth in vivo without toxicity, which correlated with induction of apoptosis and expression of ER stress related proteins in tumor tissues. Taken together, E Platinum inhibited tumor growth and induced apoptosis by ROS-mediated ER stress activation both in vitro and in vivo. Our study indicated that E Platinum may be a potential and effective treatment for gastric cancer in clinical. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  3. Agents ameliorating or augmenting the nephrotoxicity of cisplatin and other platinum compounds: a review of some recent research. (United States)

    Ali, Badreldin H; Al Moundhri, Mansour S


    Cisplatin (cis-diamminedichloroplatinum (II)) is an effective agent against various solid tumours. Despite its effectiveness, the dose of cisplatin that can be administered is limited by its nephrotoxicity. Hundreds of platinum compounds (e.g. carboplatin, oxaliplatin, nedaplatin and the liposomal form lipoplatin) have been tested over the last two decades in order to improve the effectiveness and to lessen the toxicity of cisplatin. Several agents have been tested to see whether they could ameliorate or augment the nephrotoxicity of platinum drugs. This review summarizes these studies and the possible mechanisms of actions of these agents. The agents that have been shown to ameliorate experimental cisplatin nephrotoxicity include antioxidants (e.g. melatonin, vitamin E, selenium, and many others), modulators of nitric oxide (e.g. zinc histidine complex), agents interfering with metabolic pathways of cisplatin (e.g. procaine HCL), diuretics (e.g. furosemide and mannitol), and cytoprotective and antiapoptotic agents (e.g. amifostine and erythropoietin). Only few of these agents have been tested in humans. Those agents that have been shown to augment cisplatin nephrotoxicity include nitric oxide synthase inhibitors, spironolactone, gemcitabine and others. Combining these agents with cisplatin should be avoided.

  4. Heart testing compound (United States)

    Knapp, F.F. Jr.; Goodman, M.M.


    The compound 15-(p-(/sup 125/I)-iodophenyl)-6-tellurapentadecanoic acid is disclosed as a myocardial imaging agent having rapid and pronounced uptake, prolonged myocardial retention, and low in vivo deiodination.

  5. Quinoxaline-2-carboxamide as a carrier ligand in two new platinum(ii) compounds: Synthesis, crystal structure, cytotoxic activity and DNA interaction

    NARCIS (Netherlands)

    Marques Gallego, P.; Amparo Gamiz-Gonzalez, M.; Fortea-Pérez, F. R.; Lutz, M.; Spek, A.L.; Pevec, A.; Kozlevar, B.; Reedijk, J.


    The search for platinum compounds structurally different from cisplatin has led to two new platinum(II) compounds containing quinoxaline-2-carboxamide as a carrier ligand, i.e. cis-[Pt(qnxca)(MeCN)Cl2] (1) and the [Pt(qnxca−H)(dmso)Cl] (2). Both compounds have been synthesized and characterized usin

  6. Nanocarriers for delivery of platinum anticancer drugs☆ (United States)

    Oberoi, Hardeep S.; Nukolova, Natalia V.; Kabanov, Alexander V.; Bronich, Tatiana K.


    Platinum based anticancer drugs have revolutionized cancer chemotherapy, and continue to be in widespread clinical use especially for management of tumors of the ovary, testes, and the head and neck. However, several dose limiting toxicities associated with platinum drug use, partial anti-tumor response in most patients, development of drug resistance, tumor relapse, and many other challenges have severely limited the patient quality of life. These limitations have motivated an extensive research effort towards development of new strategies for improving platinum therapy. Nanocarrier-based delivery of platinum compounds is one such area of intense research effort beginning to provide encouraging preclinical and clinical results and may allow the development of the next generation of platinum chemotherapy. This review highlights current understanding on the pharmacology and limitations of platinum compounds in clinical use, and provides a comprehensive analysis of various platinum–polymer complexes, micelles, dendrimers, liposomes and other nanoparticles currently under investigation for delivery of platinum drugs. PMID:24113520

  7. Palladium(Ⅱ) and Platinum(Ⅱ) Compounds Derived From Potentially Terdentate Ligands

    Institute of Scientific and Technical Information of China (English)

    C. López


    @@ 1Introduction Transition metalcomplexes derived from potentially terdentate ligands have attracted great interest in the late years. Among all the examples described so far, those containing palladium(Ⅱ) or platinum(Ⅱ) and ligands holding three heteroatoms with different donor abilities are particularly relevant. In compounds of this kind, the potential hemilability[1] of one of the terminal σ(M-donor atom) bonds, plays an important role in the view of their applications in homogeneous catalysis[2]. On the other hand, it is well-known that in dimetallic complexes the presence of two different metals in a close vicinity may influence their mutual cooperation in a wide variety of processes[3]. Besides that, some examples of the utility of chiral palladium( Ⅱ ) as well as platinum( Ⅱ ) complexes as precursors for organic and/or organometallic synthesis, as chiral recognitors or discriminators, or even in Bio-Medicine have also been reported[4- 6]. However, chiral heterodimetallic compounds holding ferrocenyl units and potentially terdentate ligands are scarce.

  8. Technology Development and Production of Certain Chemical Platinum Metals Compounds at JSC "Krastsvetmet"

    Institute of Scientific and Technical Information of China (English)



    In recent years JSC "Krastsvetmet" has successfully developed the production of chemically pure compounds of precious metals.Currently methods have been developed and facilities have been provided for industrial production of the following platinum metals compounds:- Rhodium (Ⅲ) chloride hydrate,rhodium (Ⅲ) chloride solution,rhodium ( Ⅲ) nitrate solution,rhodium ( Ⅲ)iodide,rhodium ( Ⅲ) sulfate,hydrated rhodium ( Ⅲ) oxide,ammonium hexachlororodiate,rhodium ( Ⅲ)phosphate solution,rhodium electrolytes;Iridium (Ⅳ) chloride hydrate,iridium (Ⅲ) chloride hydrate,ammonium hexachloroiridate (Ⅳ),hexachloriridium acid solution,hexachloriridium crystalline acid;- Ruthenium (Ⅲ) chloride hydrate,ruthenium (Ⅳ) hydroxide chloride,ruthenium (Ⅳ) hydroxide chloride solution,ammonium hexachlororuthenate,ruthenium (Ⅲ) chloride solution,potassium,diaquaoctachloronitrido diruthenate.The quality of the production meets the requirements of Russian and foreign consumers.

  9. Effects of High-Humidity Aging on Platinum, Palladium, and Gold Loaded Tin Oxide—Volatile Organic Compound Sensors

    Directory of Open Access Journals (Sweden)

    Maiko Nishibori


    Full Text Available This study is an investigation of high-humidity aging effects on the total volatile organic compound (T–VOC gas-sensing properties of platinum, palladium, and gold-loaded tin oxide (Pt,Pd,Au/SnO2 thick films. The sensor responses of the high-humidity aged Pt,Pd,Au/SnO2, a non-aged Pt,Pd,Au/SnO2, and a high-humidity aged Pt/SnO2 to T–VOC test gas have been measured. The high-humidity aging is an effective treatment for resistance to humidity change for the Pt,Pd,Au/SnO2 but not effective for the Pt/SnO2. The mechanism of the high-humidity aging effects is discussed based on the change of surface state of the SnO2 particles.

  10. Gamma-secretase inhibition combined with platinum compounds enhances cell death in a large subset of colorectal cancer cells

    Directory of Open Access Journals (Sweden)

    Feller Stephan M


    Full Text Available Abstract Background Notch signalling is essential for the development and maintenance of the colonic epithelium. Its inhibition induces a differentiation phenotype in vivo and reduces adenomas in APCmin mice. Whether Notch signals are also required in colorectal cancer (CRC has remained elusive. Therefore, 64 CRC cell lines were analysed for the occurrence of proteolytically processed, active Notch. Results 63 CRC lines contained a fragment with approximately the size of the Notch1 intracellular domain (NICD, which is required for signalling. Subsequent analyses with an antibody that specifically recognises the free Val1744 residue generated by γ-secretase-mediated cleavage of Notch1 showed that a subset of CRC cells lacks this specific Val1744-NICD. Surprisingly, inhibition of Val1744-NICD signalling with different γ-secretase inhibitors (GSI did not lead to substantial effects on CRC cell line growth or survival. However, transient activation of Erk upon GSI treatment was detected. Since cisplatin relies on Erk activation for bioactivity in some cells, platinum compounds were tested together with GSI and enhanced cell killing in a subset of Val1744-NICD-positive CRC cell lines was detected. Erk inhibition ablated this combination effect. Conclusion We conclude that γ-secretase inhibition results in activation of the MAP kinases Erk1/2 and, when used in conjunction, enhances cell death induced by platinum compounds in a large subset of colorectal cancer cell lines. Furthermore the activation of Erk appears to be of particular importance in mediating the enhanced effect seen, as its inhibition abrogates the observed phenomenon. These findings do not only highlight the importance of signalling pathway crosstalk but they may also suggest a new avenue of combination therapy for some colorectal cancers.

  11. Antioxidant properties of trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene against modification of variety of biomolecules in human blood cells treated with platinum compounds. (United States)

    Olas, Beata; Wachowicz, Barbara; Majsterek, Ireneusz; Blasiak, Janusz; Stochmal, Anna; Oleszek, Wieslaw


    A diet rich in natural antioxidants in combination with anticancer therapy is important in reducing morbidity and mortality in addition to diminishing toxicity and side effects of chemotherapeutic agents. Cisplatin (cis-diamminedichloroplatinum II, cis-Pt) is a common chemotherapeutic agent, but it causes side effects, including hematologic toxicity with changes in the biological function of blood cells. We compared the action of two phenolic compounds isolated from the bark of Yucca schidigera: trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene and resveratrol (trans-3,4',5 - trihydroxystilbene, present also in grapes and wine) on oxidative stress induced by cisplatin (used in chemotherapy) and selenium-cisplatin conjugate ([NH(3)](2)Pt(SeO(3) [Se-Pt], with a slight toxic effect on blood cells) in human blood platelets and peripheral blood lymphocytes. The trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene, like resveratrol, significantly inhibited protein carbonylation (measured by enzyme-linked immunosorbent assay and western blot analysis) in blood platelets treated with platinum compounds (10 microg/mL) and markedly reduced oxidation of thiol groups of proteins in these cells. The trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene, like resveratrol, caused a distinct reduction of platelet lipid peroxidation induced by platinum compounds. The combined action of the tested phenolic compounds with Se-Pt evoked a significant decrease in DNA damage (measured by the comet assay) in lymphocytes compared with cells treated with Se-Pt only. We conclude that one promising natural product may be trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene, because it is a stronger antioxidant in the tested models in vitro compared with resveratrol (P < 0.05). The trans-3,3',5,5'-tetrahydroxy-4'-methoxystilbene can also be useful as a protective factor against platinum compounds during chemotherapy or cancer prophylaxis.

  12. Neurotoxic Effects of Platinum Compounds: Studies in vivo on Intracellular Calcium Homeostasis in the Immature Central Nervous System

    Directory of Open Access Journals (Sweden)

    Graziella Bernocchi


    Full Text Available Platinum compounds cause significant clinical neurotoxicity. Several studies highlight neurological complications especially in paediatric oncology patients with Central Nervous System (CNS and non-CNS malignancies. To understand the toxicity mechanisms of platinum drugs at cellular and molecular levels in the immature brain, which appears more vulnerable to injury than in the adult one, we compared the effects in vivo of the most used platinum compounds, i.e., cisdichlorodiammineplatinum (cisplatin, cisPt, and the new [Pt(O,O′-acac(γ-acac(DMS] (PtAcacDMS. As models of developing brain areas, we have chosen the cerebellum and hippocampus dentate gyrus. Both areas show the neurogenesis events, from proliferation to differentiation and synaptogenesis, and therefore allow comparing the action of platinum compounds with DNA and non-DNA targets. Here, we focused on the changes in the intracellular calcium homeostasis within CNS architecture, using two immunohistochemical markers, the calcium buffer protein Calbindin and Plasma Membrane Calcium ATPase. From the comparison of the cisPt and PtAcacDMS effects, it emerges how essential the equilibrium and synergy between CB and PMCA1 is or how important the presence of at least one of them is to warrant the morphology and function of nervous tissue and limit neuroarchitecture damages, depending on the peculiar and intrinsic properties of the developing CNS areas.

  13. Biogenic platinum and palladium nanoparticles as new catalysts for the removal of pharmaceutical compounds. (United States)

    Martins, Mónica; Mourato, Cláudia; Sanches, Sandra; Noronha, João Paulo; Crespo, M T Barreto; Pereira, Inês A C


    Pharmaceutical products (PhP) are one of the most alarming emergent pollutants in the environment. Therefore, it is of extreme importance to investigate efficient PhP removal processes. Biologic synthesis of platinum nanoparticles (Bio-Pt) has been reported, but their catalytic activity was never investigated. In this work, we explored the potential of cell-supported platinum (Bio-Pt) and palladium (Bio-Pd) nanoparticles synthesized with Desulfovibrio vulgaris as biocatalysts for removal of four PhP: ciprofloxacin, sulfamethoxazole, ibuprofen and 17β-estradiol. The catalytic activity of the biological nanoparticles was compared with the PhP removal efficiency of D. vulgaris whole-cells. In contrast with Bio-Pd, Bio-Pt has a high catalytic activity in PhP removal, with 94, 85 and 70% removal of 17β-estradiol, sulfamethoxazole and ciprofloxacin, respectively. In addition, the estrogenic activity of 17β-estradiol was strongly reduced after the reaction with Bio-Pt, showing that this biocatalyst produces less toxic effluents. Bio-Pt or Bio-Pd did not act on ibuprofen, but this could be completely removed by D. vulgaris whole-cells, demonstrating that sulfate-reducing bacteria are among the microorganisms capable of biotransformation of ibuprofen in anaerobic environments. This study demonstrates for the first time that Bio-Pt has a high catalytic activity, and is a promising catalyst to be used in water treatment processes for the removal of antibiotics and endocrine disrupting compounds, the most problematic PhP. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Studies on allergic reactions after exposure to platinum compounds; Untersuchungen ueber allergische Reaktionen bei Exposition gegen Platinverbindungen (VPT 07A)

    Energy Technology Data Exchange (ETDEWEB)

    Merget, R.; Schultze-Werninghaus, G. [Berufsgenossenschaftliche Kliniken, Bergmannsheil - Universitaetsklinik, Medizinische Klinik und Poliklinik, Abt. fuer Pneumologie, Allergologie und Schlafmedizin, Bochum (Germany)


    The aim of the present study was to assess the allergic hazard potential of Pt-containing substances emitted from automotive catalytic converters for the population. This was done by determining exposure-effect relationships in subjects occupationally exposed to platinum compounds in a catalytic converter manufacturing company. The company had been deemed suitable because it could be assumed that the extensive technical industrial safety measures implemented there would make for a considerably reduced exposure to platinum compounds compared to, for example, a platinum separating plant. Exposure-effect relationships were determined on the basis of platinum measurements in a catalytic-converter-manufacturing plant and of a record of new sickness cases. [Deutsch] Ziel der Untersuchung war eine Risikoabschaetzung des Allergie-Gefaehrdungspotentials Pt-haltiger Automobilkatalysatoremittate fuer die Bevoelkerung durch Ermittlung der Expositions-Wirkungsbeziehung bei beruflich gegenueber Platinverbindungen Exponierten in einem Katalysatorfertigungsbertrieb. Der gewaehlte Katalysatorbetrieb war deshalb als geeignet betrachtet worden, weil durch weitgehende technische Arbeitsschutzmassnahmen eine wesentlich geringere Exposition gegenueber Platinverbindungen anzunehmen war als zum Beispiel in Platinscheidereien. Die Expositions-Wirkungsbeziehung sollte durch Platinmessungen in einem Katalysator-Betrieb und Erfassung der Haeufigkeit von Neuerkrankungen im Laengsschnitt definiert werden. (orig.)

  15. Kinetics and mechanism for reduction of anticancer-active tetrachloroam(m)ine platinum(IV) compounds by glutathione. (United States)

    Lemma, K; Berglund, J; Farrell, N; Elding, L I


    Glutathione (GSH) reduction of the anticancer-active platinum(IV) compounds trans-[PtCl4(NH3)(thiazole)] (1), trans-[PtCl4(cha)(NH3)] (2), cis-[PtCl4(cha)(NH3)] (3) (cha=cyclohexylamine), and cis-[PtCl4(NH3)2] (4) has been investigated at 25 degrees C in a 1.0 M aqueous medium at pH 2.0-5.0 (1) and 4.5-6.8 (2-4) using stopped-flow spectrophotometry. The redox reactions follow the second-order rate law d[Pt(IV)]/dt=k[GSH]tot[Pt(IV)], where k is a pH-dependent rate constant and [GSH]tot the total concentration of glutathione. The reduction takes place via parallel reactions between the platinum(IV) complexes and the various protolytic species of glutathione. The pH dependence of the redox kinetics is ascribed to displacement of these protolytic equilibria. The thiolate species GS is the major reductant under the reaction conditions used. The second-order rate constants for reduction of compounds 1-4 by GS- are (1.43 +/- 0.01) x 10(7), (3.86 +/- 0.03) x 10(6), (1.83 +/- 0.01) x 10(6), and (1.18 +/- 0.01) x 10(6) M(-1)s(-1), respectively. Rate constants for reduction of 1 by the protonated species GSH are more than five orders of magnitude smaller. The mechanism for the reductive elimination reactions of the Pt(IV) compounds is proposed to involve an attack by glutathione on one of the mutually trans coordinated chloride ligands, leading to two-electron transfer via a chloride-bridged activated complex. The kinetics results together with literature data indicate that platinum(IV) complexes with a trans Cl-Pt-Cl axis are reduced rapidly by glutathione as well as by ascorbate. In agreement with this observation, cytotoxicity profiles for such complexes are very similar to those for the corresponding platinum(II) product complexes. The rapid reduction within 1 s of the platinum(IV) compounds with a trans Cl-Pt-C1 axis to their platinum(II) analogs does not seem to support the strategy of using kinetic inertness as a parameter to increase anticancer activity, at least for

  16. Bioaccessibility testing of cobalt compounds. (United States)

    Stopford, Woodhall; Turner, John; Cappellini, Danielle; Brock, Tom


    Testing of metal compounds for solubility in artificial fluids has been used for many years to assist determining human health risk from exposure to specific compounds of concern. In lieu of obtaining bioavailability data from samples of urine, blood, or other tissues, these studies measured solubility of compounds in various artificial fluids as a surrogate for bioavailability. In this context, the measurement of metal "bioaccessibility" can be used as an in vitro substitute for measuring metal bioavailability. Bioaccessibility can be defined as a value representing the availability of metal for absorption when dissolved in in vitro surrogates of body fluids or juices. The aim of this study was to measure and compare the bioaccessibility of selected cobalt compounds in artificial human tissue fluids and human serum. A second aim was to initiate studies to experimentally validate an in vitro methodology that would provide a conservative estimate of cobalt bioavailability in the assessment of dose from human exposure to various species of cobalt compounds. This study evaluated the bioaccessibility of cobalt(II) from 11 selected cobalt compounds and an alloy in 2 physical forms in 5 surrogate human tissue fluids and human serum. Four (4) separate extraction times were used up to 72 hours. The effect of variables such as pH, dissolution time, and mass-ion effect on cobalt bioaccessibility were assessed as well. We found that the species of cobalt compound as well as the physico-chemical properties of the surrogate fluids, especially pH, had a major impact on cobalt solubility. Cobalt salts such as cobalt(II) sulfate heptahydrate were highly soluble, whereas cobalt alloys used in medical implants and cobalt aluminate spinels used as pigments, showed minimal dissolution over the period of the assay.

  17. Corrosion Preventive Compounds Lifetime Testing (United States)

    Hale, Stephanie M.; Kammerer, Catherine C.; Copp, Tracy L.


    Lifetime Testing of Corrosion Preventive Compounds (CPCs) was performed to quantify performance in the various environments to which the Space Shuttle Orbiter is exposed during a flight cycle. Three CPCs are approved for use on the Orbiter: RD Calcium Grease, Dinitrol AV-30, and Braycote 601 EF. These CPCs have been rigorously tested to prove that they mitigate corrosion in typical environments, but little information is available on how they perform in the unique combination of the coastal environment at the launch pad, the vacuum of low-earth orbit, and the extreme heat of reentry. Currently, there is no lifetime or reapplication schedule established for these compounds that is based on this combination of environmental conditions. Aluminum 2024 coupons were coated with the three CPCs and exposed to conditions that simulate the environments to which the Orbiter is exposed. Uncoated Aluminum 2024 coupons were exposed to the environmental conditions as a control. Visual inspection and Electro- Impedance Spectroscopy (EIS) were performed on the samples in order to determine the effectiveness of the CPCs. The samples were processed through five mission life cycles or until the visual inspection revealed the initiation of corrosion and EIS indicated severe degradation of the coating.

  18. The developmental neurotoxicity study of platinum compounds. Effects of cisplatin versus a novel Pt(II) complex on rat cerebellum. (United States)

    Cerri, Silvia; Piccolini, Valeria M; Santin, Giada; Bottone, Maria G; De Pascali, Sandra A; Migoni, Danilo; Iadarola, Paolo; Fanizzi, Francesco P; Bernocchi, Graziella


    In the field of experimental oncology, many efforts are being carried out to search new platinum-based drugs overcoming the CNS toxicity and drug resistance. One of the adopted strategies is the synthesis of platinum compounds able to form Pt-DNA adducts different from the cisplatin ones or to react with other subcellular targets. In this context a novel Pt(II) complex, [Pt(O,O'-acac)(γ-acac)(DMS)](PtAcacDMS), was synthesized which reacts preferentially with protein thiols or thioethers. In this work we investigated the in vivo effects of cisplatin and PtAcacDMS on normal development. Moreover, to verify the dose-dependence of the effects, different groups of animals were treated with 5 μg/g or 10 μg/g body weight of cisPt and PtAcacDMS. We have focused our attention on the cerebellum because it provides a useful model system to evaluate the outcomes of perinatal treatment with chemotherapeutic agents on key CNS developmental processes such as neural cells proliferation, migration and differentiation. We have demonstrated the ability of both cisPt and PtAcacDMS to reach the brain tissue once injected. The brain platinum content after PtAcacDMS treatment was notably higher (approximately 4-fold as much) than after cisPt. The platinum accumulation in the brain was still considerable 7 days after PtAcacDMS administration. However, compared with cisplatin, PtAcacDMS induces less severe changes on fundamental events of neuroarchitecture development, such as no high apoptotic events, less altered granule cell migration and Purkinje cell dendrite growth, suggesting a low neurotoxicity of this new Pt complex for normal CNS. The mild damages could be attributable to the different subcellular target of this compound as well as to a greater efficiency of the cell repair system to recognize the drug-target adducts and to repair them. Together with the previously demonstrated antineoplastic effectiveness in vitro, the findings here reported suggest PtAcacDMS as a potential

  19. Testing of Experimental Antileishmanial Compounds. (United States)


    administrative and clerical assistance and Ms. Barbara L. Harris, Laboratory Technician II, for technical assistance with this study. Their efforts are appreciated...braziliensis) leishmaniasis . Although several new compounds have been identified with activity against L. (V.) braziliensis, none have shown adequate warrant initiation of clinical trials. However, among the most promising active compounds found against visceral leishmaniasis during these

  20. Novel Platinum(II) compounds modulate insulin-degrading enzyme activity and induce cell death in neuroblastoma cells. (United States)

    Tundo, Grazia R; Sbardella, Diego; De Pascali, Sandra A; Ciaccio, Chiara; Coletta, Massimo; Fanizzi, Francesco P; Marini, Stefano


    The properties of three novel Platinum(II) compounds toward the insulin-degrading enzyme (IDE) enzymatic activity have been investigated under physiological conditions. The rationale of this study resides on previous observations that these compounds, specifically designed and synthesized by some of us, induce apoptosis in various cancer cell lines, whereas IDE has been proposed as a putative oncogene involved in neuroblastoma onset and progression. Two of these compounds, namely [PtCl(O,O'-acac)(DMSO)] and [Pt(O,O'-acac)(γ-acac)(DMS)], display a modulatory behavior, wherefore activation or inhibition of IDE activity occurs over different concentration ranges (suggesting the existence of two binding sites on the enzyme). On the other hand, [Pt(O,O'-acac)(γ-acac)(DMSO)] shows a typical competitive inhibitory pattern, characterized by a meaningful affinity constant (K i  = 0.95 ± 0.21 μM). Although all three compounds induce cell death in neuroblastoma SHSY5Y cells at concentrations exceeding 2 μM, the two modulators facilitate cells' proliferation at concentrations ≤ 1.5 μM, whereas the competitive inhibitor [Pt(O,O'-acac)(γ-acac)(DMSO)] only shows a pro-apoptotic activity at all investigated concentrations. These features render the [Pt(O,O'-acac)(γ-acac)(DMSO)] a promising "lead compound" for the synthesis of IDE-specific inhibitors (not characterized yet) with therapeutic potentiality.

  1. Identification of cisplatin-binding proteins using agarose conjugates of platinum compounds.

    Directory of Open Access Journals (Sweden)

    Takatoshi Karasawa

    Full Text Available Cisplatin is widely used as an antineoplastic drug, but its ototoxic and nephrotoxic side-effects, as well as the inherent or acquired resistance of some cancers to cisplatin, remain significant clinical problems. Cisplatin's selectivity in killing rapidly proliferating cancer cells is largely dependent on covalent binding to DNA via cisplatin's chloride sites that had been aquated. We hypothesized that cisplatin's toxicity in slowly proliferating or terminally differentiated cells is primarily due to drug-protein interactions, instead of drug-DNA binding. To identify proteins that bind to cisplatin, we synthesized two different platinum-agarose conjugates, one with two amino groups and another with two chlorides attached to platinum that are available for protein binding, and conducted pull-down assays using cochlear and kidney cells. Mass spectrometric analysis on protein bands after gel electrophoresis and Coomassie blue staining identified several proteins, including myosin IIA, glucose-regulated protein 94 (GRP94, heat shock protein 90 (HSP90, calreticulin, valosin containing protein (VCP, and ribosomal protein L5, as cisplatin-binding proteins. Future studies on the interaction of these proteins with cisplatin will elucidate whether these drug-protein interactions are involved in ototoxicity and nephrotoxicity, or contribute to tumor sensitivity or resistance to cisplatin treatment.

  2. Differential transport of platinum compounds by the human organic cation transporter hOCT2 (hSLC22A2)

    NARCIS (Netherlands)

    H. Burger (Herman); A. Zoumaro-Djayoon (Adja); A.W.M. Boersma (Anton); J. Helleman (Jozien); P.M.J.J. Berns (Els); A.H.J. Mathijssen (Ron); W.J. Loos (Walter); E.A.C. Wiemer (Erik)


    textabstractAbstract BACKGROUND: Solute carriers (SLCs), in particular organic cation transporters (OCTs), have been implicated in the cellular uptake of platinum-containing anticancer compounds. The activity of these carriers may determine the pharmacokinetics and the severity of side effects, inc

  3. High-throughput in vitro assay to evaluate the cytotoxicity of liberated platinum compounds for stimulating neural electrodes. (United States)

    Kovach, Kyle M; Kumsa, Doe W; Srivastava, Vishnupriya; Hudak, Eric M; Untereker, Darrel F; Kelley, Shawn C; von Recum, Horst A; Capadona, Jeffrey R


    It is currently unclear how the platinum (Pt) species released from platinum-containing stimulating electrodes may affect the health of the surrounding tissue. This study develops an effective system to assess the cytotoxicity of any electrode-liberated Pt over a short duration, to screen systems before future in vivo testing. A platinum electrode was stimulated for two hours under physiologically relevant conditions to induce the liberation of Pt species. The total concentration of liberated Pt species was quantified and the concentration found was used to develop a range of Pt species for our model system comprised of microglia and neuron-like cells. Under our stimulation conditions (k=2.3, charge density of 57.7μC/cm(2)), Pt was liberated to a concentration of 1ppm. Interestingly, after 24h of Pt exposure, the dose-dependent cytotoxicity plots revealed that cell death became statistically significant at 10ppm for microglia and 20ppm for neuronal cells. However, in neuron-like cell cultures, concentrations above 1ppm resulted in significant neurite loss after 24h. To our knowledge, there does not exist a simple, in vitro assay system for assessing the cytotoxicity of Pt liberated from stimulating neural electrodes. This work describes a simple model assay that is designed to be applicable to almost any electrode and stimulation system where the electrode is directly juxtaposed to the neural target. Based on the application, the duration of stimulation and Pt exposure may be varied. Published by Elsevier B.V.

  4. Quadrupole coupling constants and isomeric Moessbauer shifts for halogen-containing gold, platinum, niobium, tantalum and antimony compounds

    Energy Technology Data Exchange (ETDEWEB)

    Poleshchuk, O. K., E-mail: [Tomsk State Pedagogical University (Russian Federation); Branchadell, V. [Universitat Autonoma de Barcelona, Departament de Quimica (Spain); Ritter, R. A.; Fateev, A. V. [Tomsk State Pedagogical University (Russian Federation)


    We have analyzed by means of Density functional theory calculations the nuclear quadrupole coupling constants of a range of gold, antimony, platinum, niobium and tantalum compounds. The geometrical parameters and halogen nuclear quadrupole coupling constants obtained by these calculations substantially corresponded to the data of microwave and nuclear quadrupole resonance spectroscopy. An analysis of the quality of the calculations that employ pseudo-potentials and all-electron basis sets for the halogen compounds was carried out. The zero order regular approximation (ZORA) method is shown to be a viable alternative for the calculation of halogen coupling constants in molecules. In addition, the ZORA model, in contrast to the pseudo-potential model, leads to realistic values of all metal nuclear quadrupole coupling constants. From Klopman's approach, it follows that the relationship between the electrostatic bonding and covalent depends on the nature of the central atom. The results on Moessbauer chemical shifts are also in a good agreement with the coordination number of the central atom.

  5. Basics of sterile compounding: bubble point testing. (United States)

    Thoma, Laura


    Compounding pharmacies that compound sterile preparations must choose sterile filters that are approved for human use. They may rely on the filter manufacturer's Certificate of Quality to ensure the sterile filter is pyrogen free and has been tested for bacterial retention. The Certificate of Quality from the filter manufacturer also contains other useful information about the filter such as: flow rate and maximum pressure drop, thermal and hydraulic stress, and membrane results of the initial integrity test performed on the filter membrane with water, if a hydrophilic membrane. This article discusses the integrity test, which is often called the water bubble point test.

  6. Quinoxaline-2-carboxamide as a carrier ligand in two new platinum(II) compounds: Synthesis, crystal structure, cytotoxic activity and DNA interaction. (United States)

    Marqués-Gallego, Patricia; Gamiz-Gonzalez, M Amparo; Fortea-Pérez, Francisco R; Lutz, Martin; Spek, Anthony L; Pevec, Andrej; Kozlevčar, Bojan; Reedijk, Jan


    The search for platinum compounds structurally different from cisplatin has led to two new platinum(II) compounds containing quinoxaline-2-carboxamide as a carrier ligand, i.e. cis-[Pt(qnxca)(MeCN)Cl2] (1) and the [Pt(qnxca-H)(dmso)Cl] (2). Both compounds have been synthesized and characterized using different spectroscopic methods. In addition, single-crystal structures have been determined by X-Ray diffraction for both compounds. In each case a square planar Pt(II) is present; in (1) the qnxca is monodentate and neutral, whereas in (2) the ligand has lost a hydrogen, to form the anionic chelating ligand abbreviated as qnxca-H. The biological activity of both compounds has been investigated in a panel of seven human tumour cells, displaying poor cytotoxic activity, compared to cisplatin. The interaction of the new compounds with 1 or 2 equiv. of 9-ethylguanine has been studied using (1)H NMR, (195)Pt NMR and ESI-MS spectroscopy, finding poor reactivity of 1 towards the model base, forming only the monosubstituted adduct. Surprisingly, compound 2, which is more sterically crowded, interacts more efficiently with the 9-EtG, forming a bifunctional adduct with two 9-EtG with substitution of the dmso and the chloride ligand. Unwinding studies of pUC19 plasmid DNA by compound 1 show similar unwinding properties to cisplatin.

  7. Meeting report on 8th International Symposium on Platinum and Other Metal Coordination Compounds in Cancer Chemotherapy. (United States)

    Kelland, L R


    The platinum-based drugs, cisplatin and carboplatin, represent major agents in the chemotherapeutic treatment of a variety of types of cancer. Novel, "third-generation" agents aimed at broadening the clinical activity of this class of drug are currently undergoing clinical evaluation. These include oxaliplatin, ZD0473 and BBR3464. Clinical trials and preclinical studies are also being conducted with liposomal (SPI-077 and L-NDDP) and polymeric platinum complexes (linked to HPMA or albumin). Combination studies of cisplatin/carboplatin with other anticancer drugs such as gemcitabine and UCN-01 (7-hydroxystaurosporine) and agents designed to reduce platinum drug toxicities (e.g., BNP-7787, DIMESNA) are ongoing. Preclinically, there is interest in trans platinum complexes, terpyridine platinum(II) complexes and other metal-containing agents (ruthenium and gold).

  8. Biomineralization of platinum by microorganisms (United States)

    Pavlova, L. M.; Radomskaya, V. I.; Shumilova, L. P.; Ionov, A. M.; Sorokin, P.


    The mechanism of platinum biomineralization by microscopic fungi is displayed based on data of electron microscopy, infrared and X-ray photoelectronic spectroscopy. It was suggested the platinum sorption process by microscopic fungi has some stages. The initial interaction is carried out by the mechanisms of physical and chemical sorption. Hereafter the reduction process of adsorbed platinum ions up to zero state is performed, probably, for account of organic compounds, which are produced by fungi biomass as metabolism result, and the process terminates by nulvalent particles aggregating up to nanosize forms. Obtained data on the platinum biomineralization extends the concept concerning the character of forming platinum nanoparticles in carbonous paleobasin.

  9. Monofunctional and Higher-Valent Platinum Anticancer Agents (United States)

    Johnstone, Timothy C.; Wilson, Justin J.


    Platinum compounds represent one of the great success stories of metals in medicine. Following the serendipitous discovery of the anticancer activity of cisplatin by Rosenberg, a large number of cisplatin variants have been prepared and tested for their ability to kill cancer cells and inhibit tumor growth. These efforts continue today with increased realization that new strategies are needed to overcome issues of toxicity and resistance inherent to treatment by the approved platinum anticancer agents. One approach has been the use of so-called “non-traditional” platinum(II) and platinum(IV) compounds that violate the structure-activity relationships that governed platinum drug-development research for many years. Another is the use of specialized drug delivery strategies. Here we describe recent developments from our laboratory involving monofunctional platinum(II) complexes together with an historical account of the manner by which we came to investigate these compounds and their relationship to previously studied molecules. We also discuss work carried out using platinum(IV) prodrugs and the development of nanoconstructs designed to deliver them in vivo. PMID:23738524

  10. Microscale Group Test for Carbonyl Compounds. (United States)

    Horak, V.; Klein, R. F. X.


    Procedures are provided for a test that (1) demonstrates principles of derivatization with 2,4-dinitrophenylhydrazine; (2) is a thin layer chromatography experiment that visually demonstrates separation of colored compounds of different polarities; and (3) introduces microscale experimentation to students in sophomore organic chemistry…

  11. Cross-reactivity of Halogenated Platinum Salts (United States)

    Halogenated platinum (Pt) salts are well-known respiratory sensitizers associated with the development of asthma. People may be exposed to a variety of platinum compounds in different contexts (e.g. occupationally, automobile exhaust). Published reports suggest that sensitizati...

  12. Mono- and di-bromo platinum(IV) prodrugs via oxidative bromination: synthesis, characterization, and cytotoxicity. (United States)

    Xu, Zoufeng; Wang, Zhigang; Yiu, Shek-Man; Zhu, Guangyu


    Platinum(IV)-based anticancer prodrugs have attracted much attention due to their relative inertness under physiological conditions, being activated inside cells, and their capacity for functionalization with a variety of small-molecule or macromolecule moieties. Novel asymmetric platinum(IV) compounds synthesized through expedient and unique methods are desired. Here we utilize N-bromosuccinimide (NBS) and carry out oxidative bromination on platinum(II) drugs, namely cisplatin, carboplatin, and oxaliplatin, to obtain asymmetric and mono-bromo platinum(IV) prodrugs. Different solvents are used to obtain various compounds, and the compounds are further functionalized. Di-bromo compounds are also obtained through NBS-directed oxidative bromination in ethanol. The crystal structures of representative compounds are discussed, and the reduction potentials of some compounds are examined. A cytotoxicity test shows that the mono- and di-bromo platinum(IV) compounds are active against human ovarian cancer cells. Our study enriches the family of asymmetric platinum(IV) prodrugs and provides with a convenient strategy to obtain brominated platinum(IV) complexes.

  13. Cisplatin and platinum drugs at the molecular level. (Review). (United States)

    Boulikas, Teni; Vougiouka, Maria


    Over twenty years of intensive work toward improvement of cisplatin, and with hundreds of platinum drugs tested, has resulted in the introduction of the widely used carboplatin and of oxaliplatin used only for a very narrow spectrum of cancers. A number of interesting platinum compounds including the orally administered platinum drug JM216, nedaplatin, the sterically hindered platinum(II) complex ZD0473, the trinuclear platinum complex BBR3464, and the liposomal forms Lipoplatin and SPI-77 are under clinical evaluation. This review summarizes the molecular mechanisms of platinum compounds for DNA damage, DNA repair and induction of apoptosis via activation or modulation of signaling pathways and explores the basis of platinum resistance. Cisplatin, carboplatin, oxaliplatin and most other platinum compounds induce damage to tumors via induction of apoptosis; this is mediated by activation of signal transduction leading to the death receptor mechanisms as well as mitochondrial pathways. Apoptosis is responsible for the characteristic nephrotoxicity, ototoxicity and most other toxicities of the drugs. The major limitation in the clinical applications of cisplatin has been the development of cisplatin resistance by tumors. Mechanisms explaining cisplatin resistance include the reduction in cisplatin accumulation inside cancer cells because of barriers across the cell membrane, the faster repair of cisplatin adducts, the modulation of apoptotic pathways in various cells, the upregulation in transcription factors, the loss of p53 and other protein functions and a higher concentration of glutathione and metallothioneins in some type of tumors. A number of experimental strategies to overcome cisplatin resistance are at the preclinical or clinical level such as introduction of the bax gene, inhibition of the JNK pathway, introduction of a functional p53 gene, treatment of tumors with aldose reductase inhibitors and others. Particularly important are combinations of platinum

  14. Inhibition of thioredoxin reductase but not of glutathione reductase by the major classes of alkylating and platinum-containing anticancer compounds. (United States)

    Witte, Anne-Barbara; Anestål, Karin; Jerremalm, Elin; Ehrsson, Hans; Arnér, Elias S J


    Mammalian thioredoxin reductase (TrxR) is important for cell proliferation, antioxidant defense, and redox signaling. Together with glutathione reductase (GR) it is the main enzyme providing reducing equivalents to many cellular processes. GR and TrxR are flavoproteins of the same enzyme family, but only the latter is a selenoprotein. With the active site containing selenocysteine, TrxR may catalyze reduction of a wide range of substrates, but can at the same time easily be targeted by electrophilic compounds due to the extraordinarily high reactivity of a selenolate moiety. Here we addressed the inhibition of the enzyme by major anticancer alkylating agents and platinum-containing compounds and we compared it to that of GR. We confirmed prior studies suggesting that the nitrosourea carmustine can inhibit both GR and TrxR. We next found, however, that nitrogen mustards (chlorambucil and melphalan) and alkyl sulfonates (busulfan) efficiently inhibited TrxR while these compounds, surprisingly, did not inhibit GR. Inhibitions were concentration and time dependent and apparently irreversible. Anticancer anthracyclines (daunorubicin and doxorubicin) were, in contrast to the alkylating agents, not inhibitors but poor substrates of TrxR. We also found that TrxR, but not GR, was efficiently inhibited by both cisplatin, its monohydrated complex, and oxaliplatin. Carboplatin, in contrast, could not inhibit any of the two enzymes. These findings lead us to conclude that representative compounds of the major classes of clinically used anticancer alkylating agents and most platinum compounds may easily target TrxR, but not GR. The TrxR inhibition should thereby be considered as a factor that may contribute to the cytotoxicity seen upon clinical use of these drugs.

  15. Interpreting effects of structure variations induced by temperature and pressure on luminescence spectra of platinum(II) bis(dithiocarbamate) compounds. (United States)

    Poirier, Stéphanie; Roberts, Ryan J; Le, Debbie; Leznoff, Daniel B; Reber, Christian


    Luminescence spectra of two square-planar dithiocarbamate complexes of platinum(II) with different steric bulk, platinum(II) bis(dimethyldithiocarbamate) (Pt(MeDTC)2) and platinum(II) bis(di(o-pyridyl)dithiocarbamate) (Pt(dopDTC)2), are presented at variable temperature and pressure. The spectra show broad d-d luminescence transitions with maxima at approximately 13500 cm(-1) (740 nm). Variations of the solid-state spectra with temperature and pressure reveal intrinsic differences due to subtle variations of molecular and crystal structures, reported at 100 and 296 K for Pt(dopDTC)2. Luminescence maxima of Pt(MeDTC)2 shift to higher energy as temperature increases by +320 cm(-1) for an increase by 200 K, mainly caused by a bandwidth increase from 3065 to 4000 cm(-1) on the high-energy side of the band over the same temperature range. Luminescence maxima of Pt(dopDTC)2 shift in the opposite direction by -460 cm(-1) for a temperature increase by 200 K. The bandwidth of approximately 2900 cm(-1) does not vary with temperature. Both ground and emitting-state properties and subtle structural differences between the two compounds lead to this different behavior. Luminescence maxima measured at variable pressure show shifts to higher energy by +47 ± 3 and +11 ± 1 cm(-1)/kbar, for Pt(MeDTC)2 and Pt(dopDTC)2, respectively, a surprising difference by a factor of 4. The crystal structures indicate that decreasing intermolecular interactions with increasing pressure are likely to contribute to the exceptionally high shift for Pt(MeDTC)2.

  16. Nafion-Induced Metal-Metal Interactions in a Platinum(Ⅱ) Terpyridyl Acetylide Complex:a Luminescent Sensor for Detection of Volatile Organic Compounds

    Institute of Scientific and Technical Information of China (English)

    TONG,Qing-Xiao(佟庆笑); LI,Xiao-Hong(李晓红); WU,Li-Zhu(吴骊珠); YANG,Qing-Zheng(杨清正); ZHANG,Li-Ping(张丽萍); TUNG,Chen-Ho(佟振合)


    The platinum(Ⅱ) terpyridyl acetylide complex [Pt(terpy)(C≡CR)]C1O4 (terpy=2,2′: 6′2″-terpyridine, R=CH2CH2CH3) (1) was incorporated into Nafion membranes. At high loading the dry membranes exhibit intense photoluminescence with λmax at 707 nm from the 3MMLCT state, which was not observed in fluid solution. Upon exposure to the vapor of polar volatile organic compounds (VOC), this photoluminescence was significantly red-shifed. This process was fully reversible when the VOC-incorporated membrane was dried in air. The dramatic and reversible changes in the emission spectra made the Nafion-supported complex as an interesting sensor candidate for polar VOC.

  17. Prophage induction and mutagenicity of a series of anti-tumour platinum(II) and platinum(IV) co-ordination complexes

    NARCIS (Netherlands)

    Mattern, I.E.; Cocchiarella, L.; Kralingen, C.G. van; Lohman, P.H.M.


    Eleven platinum compounds with nitrogen donor ligands, previously tested for anti-tumour activity were studied for induction of prophage lambda and for mutagenicity in the Ames assay, with various strains of Salmonella. The compounds included cis and trans isomers of Pt(II) and Pt(IV) complexes and

  18. Testing of Compounds for Efficacy against Schistosomiasis. (United States)


    n the snail intermediate host is Oncomelani " hnsi q u ada from the Philippine Islands. Protocol WRHN:-IIa and WRHN-IIb. A total of 31 compounds were...1978. Linhagem humana, de S fanm. resistente a esquistossomicidas. Revista de Saude Publica de Sao Paulo, 12:110. 3. Dias, L.C.S., Pedro, R.J., and

  19. Neurotoxicity Caused by the Treatment with Platinum Analogues

    Directory of Open Access Journals (Sweden)

    Sousana Amptoulach


    Full Text Available Platinum agents (cisplatin, carboplatin, and oxaliplatin are a class of chemotherapy agents that have a broad spectrum of activity against several solid tumors. Toxicity to the peripheral nervous system is the major dose-limiting toxicity of at least some of the platinum drugs of clinical interest. Among the platinum compounds in clinical use, cisplatin is the most neurotoxic, inducing mainly sensory neuropathy of the upper and lower extremities. Carboplatin is generally considered to be less neurotoxic than cisplatin, but it is associated with a higher risk of neurological dysfunction if administered at high dose or in combination with agents considered to be neurotoxic. Oxaliplatin induces two types of peripheral neuropathy, acute and chronic. The incidence of oxaliplatin-induced neuropathy is related to various risk factors such as treatment schedule, cumulative dose, and time of infusion. To date, several neuroprotective agents including thiol compounds, vitamin E, various anticonvulsants, calcium-magnesium infusions, and other nonpharmacological strategies have been tested for their ability to prevent platinum-induced neurotoxicity with controversial results. Further studies on the prevention and treatment of neurotoxicity of platinum analogues are warranted.

  20. Novel multiwalled carbon nanotubes-polyaniline composite film coated platinum wire for headspace solid-phase microextraction and gas chromatographic determination of phenolic compounds. (United States)

    Du, Wei; Zhao, Faqiong; Zeng, Baizhao


    A novel multiwalled carbon nanotubes-polyaniline composite (MWCNTs-PANI) film coated platinum wire was fabricated through electrochemical deposition. The coating was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectrophotometry and thermogravimetry. It was found that the coating was porous and had large specific area and adsorption capacity; in the composite MWCNTs and polyaniline interacted with each other and the film kept stable up to 320 degrees C. The as-made fiber was used for the headspace solid-phase microextraction (HS-SPME) of some phenolic compounds (i.e. 2-chlorophenol, 2,4-dichlorophenol, 2-methylphenol, 3-methylphenol, 2,6-dimethylphenol, 2-nitrophenol), followed by gas chromatographic analysis. The MWCNTs-PANI coating showed better analytical performance than PANI. Under the optimized conditions, the detection limits were 1.89-65.9 ng L(-1), the relative standard deviations (RSDs) were 2.7-6.5% for six successive measurements with single fiber, the RSDs for fiber-to-fiber were 5.2-12.4%, the linear ranges exceeded two magnitudes with correlation coefficient above 0.992. The fiber could be used for more than 250 times without decrease of efficiency. The proposed method was successfully applied to the extraction and determination of phenolic compounds in water sample, and the recoveries were 87.7-111.5% for different analytes. In addition, the fiber also presented advantages of easy preparation and low cost. Therefore, it is a promising SPME fiber.

  1. Bulky N(,N)-(di)alkylethane-1,2-diamineplatinum(II) compounds as precursors for generating unsymmetrically substituted platinum(IV) complexes. (United States)

    Pichler, Verena; Göschl, Simone; Meier, Samuel M; Roller, Alexander; Jakupec, Michael A; Galanski, Markus; Keppler, Bernhard K


    Investigations of the influence of bulky groups in the equatorial ligand sphere of platinum(IV) compounds on the complexes' stability and reaction pattern were performed. Four dihydroxidoplatinum(IV) complexes were reacted with anhydrides, cinnamoyl chloride, and n-propyl isocyanate and yielded the symmetric dicarboxylated products or, if steric hindrance was observed, unsymmetrically substituted monocarboxylated analogues. With the aim of raising the steric demand, the following ligands were chosen: N-cyclohexylethane-1,2-diamine, N,N-dimethylethane-1,2-diamine, N,N-diethylethane-1,2-diamine, and N,N-diisopropylethane-1,2-diamine. All of the novel complexes were characterized by electrospray ionization mass spectrometry (ESI-MS), one- and two-dimensional NMR spectroscopy, elemental analysis, and reversed-phase HPLC; complexes B3, C3, C6, and D4 were also analyzed by X-ray diffraction. Additionally, the cytotoxicities of 10 compounds toward the cisplatin-sensitive cell line CH1 and the intrinsically cisplatin-resistant cell lines A549 and SW480 were investigated, and IC50 values down to the nanomolar range were found. To aid in the interpretation of structure-activity relationships, log k(w) values as a measure for the lipophilicity were determined for all of the new complexes, and the rates of reduction of C1, C3, and C4 relative to satraplatin were determined by means of NMR spectroscopy and ESI-MS.

  2. Neutral and ionic platinum compounds containing a cyclometallated chiral primary amine: synthesis, antitumor activity, DNA interaction and topoisomerase I-cathepsin B inhibition. (United States)

    Albert, Joan; Bosque, Ramon; Crespo, Margarita; Granell, Jaume; López, Concepción; Martín, Raquel; González, Asensio; Jayaraman, Anusha; Quirante, Josefina; Calvis, Carme; Badía, Josefa; Baldomà, Laura; Font-Bardia, Mercè; Cascante, Marta; Messeguer, Ramon


    The synthesis and preliminary biological evaluation of neutral and cationic platinum derivatives of chiral 1-(1-naphthyl)ethylamine are reported, namely cycloplatinated neutral complexes [PtCl{(R or S)-NH(2)CH(CH(3))C(10)H(6)}(L)] [L = SOMe(2) ( 1-R or 1-S ), L = PPh(3) (2-R or 2-S), L = P(4-FC(6)H(4))(3) (3-R), L = P(CH(2))(3)N(3)(CH(2))(3) (4-R)], cycloplatinated cationic complexes [Pt{(R)-NH(2)CH(CH(3))C(10)H(6)}{L}]Cl [L = Ph(2)PCH(2)CH(2)PPh(2) (5-R), L = (C(6)F(5))(2)PCH(2)CH(2)P(C(6)F(5))(2) (6-R)] and the Pt(ii) coordination compound trans-[PtCl(2){(R)-NH(2)CH(CH(3))C(10)H(6)}(2)] (7-R). The X-ray molecular structure of 7-R is reported. The cytotoxic activity against a panel of human adenocarcinoma cell lines (A-549 lung, MDA-MB-231 and MCF-7 breast, and HCT-116 colon), cell cycle arrest and apoptosis, DNA interaction, topoisomerase I and cathepsin B inhibition, and Pt cell uptake of the studied compounds are presented. Remarkable cytotoxicity was observed for most of the synthesized Pt(ii) compounds regardless of (i) the absolute configuration R or S, and (ii) the coordinated/cyclometallated (neutral or cationic) nature of the complexes. The most potent compound 2-R (IC(50) = 270 nM) showed a 148-fold increase in potency with regard to cisplatin in HCT-116 colon cancer cells. Preliminary biological results point out to different biomolecular targets for the investigated compounds. Neutral cyclometallated complexes 1-R and 2-R, modify the DNA migration as cisplatin, cationic platinacycle 5-R was able to inhibit topoisomerase I-promoted DNA supercoiling, and Pt(ii) coordination compound 7-R turned out to be the most potent inhibitor of cathepsin B. Induction of G-1 phase ( 2-R and 5-R ), and S and G-2 phases (6-R) arrests are related to the antiproliferative activity of some representative compounds upon A-549 cells. Induction of apoptosis is also observed for 2-R and 6-R.

  3. Proficiency test for heavy metals in compound feed

    NARCIS (Netherlands)

    Pereboom, D.P.K.H.; Elbers, I.J.W.; Jong, de J.; Lee, van der M.K.; Nijs, de W.C.M.


    The here described proficiency test for heavy metals in compound feed was organised by RIKILT, Wageningen UR in accordance with ISO 17043. RIKILT Wageningen UR has an ISO/IEC 17043 accreditation for proficiency tests of residues in products of animal origin. However, this specific test is not part

  4. Batch leaching tests of motherboards to assess environmental contamination by bromine, platinum group elements and other selected heavy metals. (United States)

    Almeida, César; Grosselli, Melina; González, Patricia; Martínez, Dante; Gil, Raúl


    In this study, a batch leaching test was executed to evaluate the toxicity associated with chemicals contained in motherboards. The leaching solutions used were distilled water, nitric acid, acetic acid and synthetic acid rain solution. A total of 21 elements including Ag, As, Au, Br, Cd, Co, Cr, Cu, Hf, Ir, Mn, Ni, Os, Pb, Pd, Pt, Rd, Rh, Se, U and Zn were analyzed. In this study, the pH values of all the leachates fell within the range of 2.33-4.88. The highest concentrations of metals were obtained from the acid rain solution, whilst the maximum value of bromine was achieved with solution of acetic acid. Appreciable concentrations of platinum group elements were detected with concentrations around 3.45, 1.43, 1.21 and 22.19 µg L(-1) for Ir, Pd, Pt and Rh, respectively. The different leaching of the motherboards revealed the predominant presence of the toxic substances in the leached from the e-waste.

  5. In vitro cytotoxicity, pharmacokinetics and ex vivo pharmacodynamics of a new platinum compound, cis-malonato [(4R,5R-4,5-bis(aminomethyl)-1,3-dioxolane-2-spiro-1'-cyclopentane] platinum (II). (United States)

    Kim, D K; Kim, H T; Cho, Y B; Kim, T S; Kim, K H; Hong, W S


    The in vitro cytotoxicity of a new platinum complex, cis-malonato [(4R, 5R)-4,5-bis(aminomethyl)-1,3-dioxolane 2- spiro 1' cyclo-pentane]platinum(II) (SKI 2054R) and cisplatin (CDDP) was evaluated against two human stomach adenocarcinoma cell lines (MKN-45 and KATO III) and a human lung adenocarcinoma cell line (PC-14). The in vitro 50% inhibitory concentration (IC50) values of SKI 2054R and CDDP against MKN-45, KATO III, and PC-14 were 1.21 and 0.51, 2.11 and 0.83, and 2.90 and 0.77 micrograms/ml, respectively. The pharma-cokinetic and ex vivo pharmacodynamic studies on SKI 2054R and CDDP were performed in beagle dogs. Equitoxic doses of SKI 2054R and CDDP (7.0 and 3.0 mg/kg, respectively) were administered i.v. bolus to beagle dose in a randomized crossover study. Plasma samples were analyzed for platinum by flameless atomic absorption spectrophotometry. Plasma concentrations of total and ultrafiltrable platinum for the two drugs declined in a biexponential fashion. The mean area under the concentration-tine curve (AUC(0)--> infinity) determined for ultrafiltrable platinum derived from SKI 2054R, as an active component was 6.61 +/- 2.34 micrograms . h/ml (mean +/- S.D.), with an initial half-life of 0.26 +/- 0.14 h, a terminal half-life of 1.57 +/- 0.71 hour, a total clearance of 17.65 +/- 4.99 ml/min/kg, and a steady-state volume of distribution of 1.46 +/- 0.11 l/kg. The ex vivo antitumor activity of SKI 2054R was assessed using the ultrafiltrable plasma against MKN-45, KATO III, and PC-14 by tetrazolium-dye (MTT) assay and was compared with that of CDDP using the antitumor index (ATI) determined from the ex vivo pharmacodynamic results of inhibition rates (%) versus time curves. The mean ATI value recorded for SKI 2054R was higher than that noted for CDDP; however, statistical difference was not observed between SKI 2054R and CDDP, suggesting that the antitumor activity of SKI 2054R is comparable to that of CDDP. These results suggest that SKI 2054R is a new

  6. Platinum impact assessment


    Yip, Joyce Pui Yan


    This paper presents a comprehensive strategic analysis of Company X's strategies to mitigate its risks from volatile platinum prices, since Platinum is a critical component of fuel cells. It is recommended that Company X consider leasing platinum to lower cash flow requirements to meet its platinum demand over the next 5 years. A shorter platinum leasing period will reduce Company X's platinum market risk. OEMs can set up metal accounts with catalyst suppliers to eliminate Company X from plat...

  7. Iron(III-salophene: an organometallic compound with selective cytotoxic and anti-proliferative properties in platinum-resistant ovarian cancer cells.

    Directory of Open Access Journals (Sweden)

    Thilo S Lange

    Full Text Available BACKGROUND: In this pioneer study to the biological activity of organometallic compound Iron(III-salophene (Fe-SP the specific effects of Fe-SP on viability, morphology, proliferation, and cell-cycle progression on platinum-resistant ovarian cancer cell lines were investigated. METHODOLOGY/PRINCIPAL FINDINGS: Fe-SP displayed selective cytotoxicity against SKOV-3 and OVCAR-3 (ovarian epithelial adenocarcinoma cell lines at concentrations between 100 nM and 1 microM, while the viability of HeLa cells (epithelial cervix adenocarcinoma or primary lung or skin fibroblasts was not affected. SKOV-3 cells in contrast to fibroblasts after treatment with Fe-SP revealed apparent hallmarks of apoptosis including densely stained nuclear granular bodies within fragmented nuclei, highly condensed chromatin and chromatin fragmentation. Fe-SP treatment led to the activation of markers of the extrinsic (Caspase-8 and intrinsic (Caspase-9 pathway of apoptosis as well as of executioner Caspase-3 while PARP-1 was deactivated. Fe-SP exerted effects as an anti-proliferative agent with an IC(50 value of 300 nM and caused delayed progression of cells through S-phase phase of the cell cycle resulting in a complete S-phase arrest. When intra-peritoneally applied to rats Fe-SP did not show any systemic toxicity at concentrations that in preliminary trials were determined to be chemotherapeutic relevant doses in a rat ovarian cancer cell model. CONCLUSION/SIGNIFICANCE: The present report suggests that Fe-SP is a potent growth-suppressing agent in vitro for cell lines derived from ovarian cancer and a potential therapeutic drug to treat such tumors in vivo.

  8. End-preparation assessments and tests for compounded sterile preparations. (United States)

    McElhiney, Linda F


    Outsourcing has become a necessity to obtain sterile products that are currently on backorder. Because of the expense of outsourcing sterile compounding, pharmacy leadership in health systems are now considering the option of insourcing and batch preparing compounded sterile preparations, which can be a viable option for a health system. It can significantly decrease drug-spending costs, and the pharmacy has a complete record of the compounding process. The key to preparing high-quality, safe, sterile preparations and meeting United States Pharmacopeia standards is end-preparation assessments and tests.

  9. Testing system for wireless platinum resistance temperature sensor%无线铂电阻温度传感器测试系统

    Institute of Scientific and Technical Information of China (English)

    唐慧强; 鲍磊磊; 李超


    为实现对铂电阻温度传感器的自动测试,设计了基于ZigBee的铂电阻的测试系统.多个高精度微型铂电阻测试节点组网后把测试数据通过汇聚节点传输到计算机.在Windows的开发平台下,利用Delphi7.0+ SQL Server2000技术进行软件研发,实现了铂电阻数据的自动采集、处理、传输、管理、性能评判等功能为一体的自动化测试系统,解决了传统测试系统需要大量布线的问题,提高了铂电阻温度传感器测试效率.%In order to realize automatic testing of the platinum resistance temperature sensor, a wireless platinum resistance test system based on ZigBee technology is designed. The test data of many platinum resistances can be sunk to the main computer by the high precision micro endpoints, and the PC-based test software is designed in Windows system by using Delphi7.0 and SQL Server2000. The automatic testing system is realized with the function of data acquisition, processing, management and performance evaluation. The problem that requires lots of wires existed in the traditional testing system is solved, and the test efficiency of the temperature sensors is improved.

  10. Pharmacokinetics and antitumor activity of a new platinum compound, cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1, 3- dioxolane]platinum(II), as determined by ex vivo pharmacodynamics. (United States)

    Kim, D K; Kim, H T; Tai, J H; Cho, Y B; Kim, T S; Kim, K H; Park, J G; Hong, W S


    The pharmacokinetics and ex vivo pharmacodynamics studies on cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1, 3- dioxolane]platinum(II) (SKI 2053R, NSC D644591), cisplatin (CDDP), and carboplatin (CBDCA) were performed in beagle dogs. Equitoxic doses of SKI 2053R, CDDP, and CBDCA (7.5, 2.5, and 15.0 mg/kg, respectively) were given by i.v. bolus to three beagle dogs in a randomized crossover study. Plasma samples were analyzed for platinum by flameless atomic absorption spectrophotometry. Plasma concentrations of total and ultrafiltrable platinum for the three drugs declined in a biexponential fashion. The mean area under the concentration-time curve (AUC0-->infinity) determined for ultrafiltrable platinum derived from SKI 2053R, as an active component, was 7.72 +/- 2.74 micrograms h ml-1 (mean +/- SD), with an initial half-life of 0.37 +/- 0.20 h, a terminal half-life of 2.19 +/- 0.93 h, a total clearance of 16.83 +/- 4.76 ml min-1 kg-1, and a steady-state volume of distribution of 1.57 +/- 0.30 l/kg. The ex vivo antitumor activity of SKI 2053R was assessed using the ultrafiltrable plasma against two human lung-adenocarcinoma cell lines (PC-9 and PC-14) and five stomach-adenocarcinoma cell lines (MKN-45, KATO III, SNU-1, SNU-5, and SNU-16) by tetrazolium-dye (MTT) assay and was compared with that of CDDP and CBDCA using an antitumor index (ATI) determined from the ex vivo pharmacodynamic results of inhibition rates (%) versus time curves. The mean ATI value was shown to be ranked in the following order: SKI 2053R > CBDCA > CDDP. The mean ATI values recorded for SKI 2053R and CBDCA were significantly (P < 0.05) higher than that noted for CDDP; however, no statistically significant difference was observed between SKI 2053R and CBDCA, suggesting that the antitumor activity of SKI 2053R is superior to that of CDDP and is equivalent to that of CBDCA. These results suggest that SKI 2053R is a promising candidate for further development as a clinically useful

  11. Optimization of the route of platinum drugs administration to optimize the concomitant treatment with radiotherapy for glioblastoma implanted in the Fischer rat brain


    Charest, Gabriel; Sanche, Léon; Fortin, David; Mathieu, David; Paquette, Benoit


    Treatment of glioblastoma with platinum compounds modestly improves progression-free survival and may cause toxic effects which prevent use at higher dose that would otherwise improve the antineoplastic effect. To reduce toxicity, we propose to encapsulate the platinum drug in a liposome. We have also tested three methods of drug administration (intra-venous, intra-arterial and intra-arterial combined with blood brain barrier disruption) to determine which one optimizes the tumor cell uptake,...

  12. PLATINUM AND FUEL CELLS (United States)

    Platinum requirements for fuel cell vehicles (FCVS) have been identified as a concern and possible problem with FCV market penetration. Platinum is a necessary component of the electrodes of fuel cell engines that power the vehicles. The platinum is deposited on porous electrodes...

  13. Platinum(IV) coordination compounds containing 5-methyl-1,2,4-triazolo[1,5- a]pyrimidin-7(4 H)-one as nonleaving ligand. Molecular and cytotoxicity in vitro characterization (United States)

    Łakomska, Iwona; Fandzloch, Marzena; Wojtczak, Andrzej; Szłyk, Edward


    Novel platinum(IV) coordination compounds with 5-methyl-1,2,4-triazolo[1,5- a]pyrimidin-7(4 H)-one (HmtpO): cis- trans-[PtCl 2(OH) 2(NH 3)(HmtpO)] ( 1), cis- trans-[PtCl 5(HmtpO)][(CH 3) 2NH 2] ( 2) have been prepared and structurally characterized by spectroscopic methods ( 1H, IR and X-ray crystallography ( 2)). The X-ray results indicate that the local geometry around the platinum(IV) centre approximates a typical octahedral arrangement with nitrogen atom N3 of the HmtpO and three chloride atoms in equatorial positions. The remaining two axial positions are occupied by two chlorides. The preliminary assessment of antitumor properties of ( 1) was performed as an in vitro antiproliferative activity against HL-60 human acute promyelocytic leukemia and HCV29T bladder cancer. The cis- trans-[PtCl 2(OH) 2(NH 3)(HmtpO)] ( 1) exhibits higher cytotoxic activity against HL-60 (IC 50 = 6.4 μM) than cisplatin.

  14. Fate of platinum metals in the environment. (United States)

    Pawlak, Justyna; Łodyga-Chruścińska, Elżbieta; Chrustowicz, Jakub


    For many years now automotive exhaust catalysts have been used to reduce the significant amounts of harmful chemical substances generated by car engines, such as carbon monoxide, nitrogen oxides, and aromatic hydrocarbons. Although they considerably decrease environmental contamination with the above-mentioned compounds, it is known that catalysts contribute to the environmental load of platinum metals (essential components of catalysts), which are released with exhaust fumes. Contamination with platinum metals stems mainly from automotive exhaust converters, but other major sources also exist. Since platinum group elements (PGEs): platinum (Pt), palladium (Pd), rhodium (Rh), ruthenium (Ru) and iridium (Ir) seem to spread in the environment and accumulate in living organisms, they may pose a threat to animals and humans. This paper discusses the modes and forms of PGE emission as well as their impact on the environment and living organisms.

  15. The effects of platinum on nickel electrodes in the nickel hydrogen cell (United States)

    Zimmerman, Albert H.


    Interactions of platinum and platinum compounds with the nickel electrode that are possible in the nickel hydrogen cell, where both the nickel electrode and a platinum catalyst hydrogen electrode are in intimate contact with the alkaline electrolyte, are examined. Additionally, a mechanism of nickel cobalt oxyhydroxide formation in NiH2 cells is presented.

  16. Qualification Testing of Engineering Camera and Platinum Resistance Thermometer (PRT) Sensors for Mars Science Laboratory (MSL) Project under Extreme Temperatures to Assess Reliability and to Enhance Mission Assurance (United States)

    Ramesham, Rajeshuni; Maki, Justin N.; Cucullu, Gordon C.


    Package Qualification and Verification (PQV) of advanced electronic packaging and interconnect technologies and various other types of qualification hardware for the Mars Exploration Rover/Mars Science Laboratory flight projects has been performed to enhance the mission assurance. The qualification of hardware (Engineering Camera and Platinum Resistance Thermometer, PRT) under extreme cold temperatures has been performed with reference to various project requirements. The flight-like packages, sensors, and subassemblies have been selected for the study to survive three times (3x) the total number of expected temperature cycles resulting from all environmental and operational exposures occurring over the life of the flight hardware including all relevant manufacturing, ground operations and mission phases. Qualification has been performed by subjecting above flight-like qual hardware to the environmental temperature extremes and assessing any structural failures or degradation in electrical performance due to either overstress or thermal cycle fatigue. Experiments of flight like hardware qualification test results have been described in this paper.

  17. Stabilizing platinum in phosphoric acid fuel cells (United States)

    Remick, R. J.


    A carbon substrate for use in fabricating phosphoric acid fuel cell cathodes was modified by catalytic oxidation to stabilize the platinum catalyst by retarding the sintering of small platinum crystallites. Results of 100-hour operational tests confirmed that the rate of platinum surface area loss observed on catalytically oxidized supports was less than that observed with unmodified supports of the same starting material. Fuel cell electrodes fabricated from Vulcan XC-72R, which was modified by catalytic in a nitric oxide atmosphere, produced low platium sintering rates and high activity for the reduction of oxygen in the phosphoric acid environment.

  18. Selenium-platinum coordination compounds as novel anticancer drugs: selectively killing cancer cells via a reactive oxygen species (ROS)-mediated apoptosis route. (United States)

    Zeng, Lingwu; Li, Yang; Li, Tianyu; Cao, Wei; Yi, Yu; Geng, Weijia; Sun, Zhiwei; Xu, Huaping


    We report the preparation of selenium-containing platinum-based anticancer drug EG-Se/Pt. EG-Se/Pt was obtained from the coordination of selenium-containing molecules (EG-Se) with cisplatin (CDDP). The structure of EG-Se/Pt was characterized by (1) H and (77) Se NMR spectroscopy, XPS, ESI-MS, and MALDI-TOF. In aqueous solution, EG-Se/Pt self-assembles to form spherical aggregates. EG-Se/Pt shows enhanced stability against dilution and high salt concentration compared with EG-Se. EG-Se/Pt induces cell apoptosis via reactive oxygen species (ROS), which leads to high selectivity between cancer cells and normal cells in cytotoxicity assays. More importantly, EG-Se/Pt effectively inhibits tumor growth in vivo in tumor-bearing mice. It is anticipated that tuning the ROS level through the assembly of selenium-containing molecules can be a general method to realize anticancer selectivity.

  19. Platinum group metal nitrides and carbides: synthesis, properties and simulation

    Energy Technology Data Exchange (ETDEWEB)

    Ivanovskii, Alexander L [Institute of Solid State Chemistry, Urals Branch of the Russian Academy of Sciences, Ekaterinburg (Russian Federation)


    Experimental and theoretical data on new compounds, nitrides and carbides of the platinum group 4d and 5d metals (ruthenium, rhodium, palladium, osmium, iridium, platinum), published over the past five years are summarized. The extreme mechanical properties of platinoid nitrides and carbides, i.e., their high strength and low compressibility, are noted. The prospects of further studies and the scope of application of these compounds are discussed.

  20. Behind platinum's sparkle. (United States)

    Yam, Vivian W W


    As a rare and precious metal that is also resistant to wear and tarnish, platinum is known to be particularly well-suited to jewellery. Vivian Yam reflects on how, beyond its prestigious image, platinum has also found its way into a variety of fields ranging from the petrochemical to the pharmaceutical industry.

  1. Standard Test Method for Preparing Aircraft Cleaning Compounds, Liquid Type, Water Base, for Storage Stability Testing

    CERN Document Server

    American Society for Testing and Materials. Philadelphia


    1.1 This test method covers the determination of the stability in storage, of liquid, water-base chemical cleaning compounds, used to clean the exterior surfaces of aircraft. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  2. Synthesis, characterization, and biological activity of platinum II, III, and IV pivaloamidine complexes. (United States)

    Sinisi, Marilù; Gandin, Valentina; Saltarella, Teresa; Intini, Francesco P; Pacifico, Concetta; Marzano, Christine; Natile, Giovanni


    Imino ligands have proven to be able to activate the trans geometry of platinum(II) complexes towards antitumor activity. These ligands, like aromatic N-donor heterocycles, have a planar shape but, different from the latter, have still an H atom on the coordinating nitrogen which can be involved in H-bond formation. Three classes of imino ligands have been extensively investigated: iminoethers (HN=C(R)OR'), ketimines (HN=CRR'), and amidines (HN=C(R)NR'R″). The promising efficacy of the platinum compounds with amidines (activity comparable to that of cisplatin for cis complexes and much greater than that of transplatin for trans complexes) prompted us to extend the investigation to amidine complexes with a bulkier organic residue (R = t-Bu). The tert-butyl group can confer greater affinity for lipophilic environments, thus potentiating the cellular uptake of the compound. In the present study we describe the synthesis and characterization of pivaloamidine complexes of platinum(II), (cis and trans-[PtCl2(NH3){Z-HN=C(t-Bu)NH2}] and cis and trans-[PtCl2{Z-HN=C(t-Bu)NH2}2]), platinum(III) ([Pt2Cl4{HN=C(t-Bu)NH}2(NH3)2]), and platinum(IV) (trans-[PtCl4(NH3){Z-HN=C(t-Bu)NH2}] and trans-[PtCl4{Z-HN=C(t-Bu)NH2}2]). The cytotoxicity of all new Pt complexes was tested toward a panel of cultured cancer cell lines, including cisplatin and multidrug resistant variants. In addition, cellular uptake and DNA binding, perturbations of cell cycle progression, induction of apoptosis, and p53 activation were investigated for the most promising compound trans-[PtCl2(NH3){Z-HN=C(t-Bu)NH2}]. Remarkably, the latter complex was able to overcome both acquired and intrinsic cisplatin resistance.

  3. The synthesis, spectroscopic, X-ray characterization and in vitro cytotoxic testing results of activity of five new trans-platinum(IV) complexes with functionalized pyridines. (United States)

    Rakić, Gordana M; Grgurić-Šipka, Sanja; Kaluđerović, Goran N; Bette, Martin; Filipović, Lana; Aranđelović, Sandra; Radulović, Siniša; Tešić, Zivoslav Lj


    Platinum(IV) complexes with general formulas [Pt(L(1-2))(2)Cl(4)], where L(1-2) are 3-acetylpyridine (1) and 4-acetylpyridine (2) respectively, and [Pt(HL(3-5))(2)Cl(2)], where H(2)L(3-5) are 2,3-pyridinedicarboxylic acid (3), 2,4-pyridinedicarboxylic acid (4) and 2,5-pyridinedicarboxylic acid (5) respectively, were prepared by the reaction of K(2)[PtCl(6)] with the corresponding ligand in 1:2 M ratio in water. The complexes were characterized by elemental analysis and IR and NMR spectroscopy. The structures of complexes 2 and 5 were determined by X-ray crystallography, which revealed the trans orientation of chloride anions around platinum(IV) in the case of both complexes. The antiproliferative activity was investigated in six tumor cell lines (human cervical carcinoma cells (HeLa), murine melanoma cells (B16), human breast carcinoma cells (MDA-MB-453), human colon carcinoma cells (LS-174), transformed human umbilical vein endothelial cells (EA.hy 926) and murine endothelial cells (MS1)) and in one non-tumor cell line-human fetal lung fibroblast cells (MRC-5). Cytotoxicity studies indicated that Pt(IV) complexes with acetyl-substituted pyridine ligands exhibit significantly higher in vitro antiproliferative activity than the complexes with carboxylato-substituted pyridines. Complexes 1 and 2 showed antiproliferative activity in all tested tumor cell lines, with the highest potential in human endothelial cells EA.hy 926, since they had IC(50) values of 13.8 ± 5.8 μM and 23.4 ± 3.3 μM, respectively and were more active than cisplatin. Complexes 1 and 2 exhibited lower toxicity against the non-tumor human lung fibroblast cell line (MRC-5) than against most of the tested tumor cell lines. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  4. Under-Reported Aspects of Platinum Drug Pharmacology

    Directory of Open Access Journals (Sweden)

    Dirk Theile


    Full Text Available Platinum drugs remain the backbone of many antineoplastic regimens. Among the numerous chemical or pharmacological effects of platinum drugs, some aspects tend to be under-reported. Thus, this perspective paper intends to stress some neglected properties of platinum drugs: first, the physico-chemical characteristics (aquation reaction kinetics that determine site-specific toxicity; second, the impact on RNA molecules. Knowledge of the ‘RNA world’ has dramatically changed our understanding of cellular and molecular biology. The inherent RNA-crosslinking properties should make platinum-based drugs interact with coding and non-coding RNAs. Third, we will discuss the impact on the immune system, which is now recognized to substantially contribute to chemotherapy efficacy. Together, platinum drugs are in fact old drugs, but are worth re-focusing on. Many aspects are still mysterious but can pave the way to new drugs or an improved application of the already existing compounds.

  5. Platinum hypersensitivity and desensitization. (United States)

    Miyamoto, Shingo; Okada, Rika; Ando, Kazumichi


    Platinum agents are drugs used for various types of cancer. With increased frequency of administration of platinum agents, hypersensitivity reactions appear more frequently, occurring in over 25% of cases from the seventh cycle or second line onward. It then becomes difficult to conduct treatment using these agents. Various approaches have been investigated to address hypersensitivity reactions to platinum agents. Desensitization, which gradually increases the concentration of the anticancer drug considered to be the antigen until the target dosage, has been reported as being particularly effective, with a success rate of 80-100%. The aims of this paper are to present the current findings regarding hypersensitivity reactions to platinum agents and to discuss attempts of using desensitization against hypersensitivity reactions worldwide. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email:

  6. Heterogeneous platinum-catalyzed hydrogenation of dialkyl(diolefin)platinum(II) complexes: A new route to platinum surface alkyls


    McCarthy, Thomas J.; Shih, Yen-Shiang; Whitesides, George M.


    Platinum metal catalyzes the reduction of dialkyl(diolefin)platinum(II) complexes by dihydrogen to alkanes and platinum(0). The reaction involves adsorption of the platinum(II) complex on the platinum(0) catalyst surface with conversion of the alkyl moieties to platinum surface alkyls; these appear as alkane products. The platinum atom originally present in the soluble organoplatinum species becomes part of the platinum(0) surface.

  7. Testing Experimental Compounds against American Cutaneous and Mucocutaneous Leishmaniasis (United States)


    neither of thiese imida - zoles shows promise for further development. They will not be tested further. C. Combination Chemotherapy Three types of...From 1980 - 1982, five 8-aminoquinolines, two imida - zoles, and the antimalarial primaquine phosphate were tested for efficacy as antileishmanial agents

  8. Síntese e caracterização de um novo complexo de platina (IV a partir de seu análogo de platina (II utilizando iodo molecular como agente oxidante: uma rota sintética interessante para obtenção de novos complexos de platina Synthesis and characterization of a novel platinum (IV complex from its platinum (II analogue using molecular iodine as an oxidizing agent: an interesting synthetic route for the preparation of new platinum complexes

    Directory of Open Access Journals (Sweden)

    Wendell Guerra


    Full Text Available In an attempt to reduce toxicity and widen the spectrum of activity of cisplatin and its analogues, much attention has been focused on designing new platinum complexes. This work reports the synthesis and characterization of novel compounds of the platinum (II and platinum (IV containing 2-furoic hydrazide acid and iodide as ligands. Although the prepared compounds do not present the classical structure of biologically active platinum analogues, they could be potentially active or useful as precursors to prepare antitumor platinum complexes. The reported compounds were characterized by ¹H NMR, 13C NMR, 195Pt NMR, IR and elemental analyses.

  9. Interlayer tunnelling mechanism : experimental test of single layer compounds

    NARCIS (Netherlands)

    Tsvetkov, AA; van der Marel, D; Dulic, D; Molegraaf, HJ; Kolesnikov, NN; Willemsen, B; Ren, ZF; Bozovic,; Pavuna, D


    The c-axis optical properties of cuprate superconductors have been studied by grazing angle reflectivity technique. We tested the interlayer tunnelling (ILT) model of high temperature superconductivity and showed that the basic relation between the condensation energy of the superconducting state

  10. Alternative testing strategies for predicting developmental toxicity of antifungal compound

    NARCIS (Netherlands)

    Li, H.


    Determination of safe human exposure levels of chemicals in toxicological risk assessments largely relies on animal toxicity data. In these toxicity studies, the highest number of animals are used for reproductive and developmental toxicity testing. Because of economic and ethical reasons, there is

  11. Interlayer tunnelling mechanism : experimental test of single layer compounds

    NARCIS (Netherlands)

    Tsvetkov, AA; van der Marel, D; Dulic, D; Molegraaf, HJ; Kolesnikov, NN; Willemsen, B; Ren, ZF; Bozovic,; Pavuna, D


    The c-axis optical properties of cuprate superconductors have been studied by grazing angle reflectivity technique. We tested the interlayer tunnelling (ILT) model of high temperature superconductivity and showed that the basic relation between the condensation energy of the superconducting state an

  12. Oxygen Reduction on Platinum

    DEFF Research Database (Denmark)

    Nesselberger, Markus

    This thesis investigates the electro reduction of oxygen on platinum nanoparticles, which serve as catalyst in low temperature fuel cells. Kinetic studies on model catalysts as well as commercially used systems are presented in order to investigate the particle size effect, the particle proximity...... carbon (HSAC) supported Pt nanoparticle (Pt/C) catalysts (of various size between 1 and 5 nm). The difference in SA between the individual Pt/C catalysts (1 to 5 nm) is very small and within the error of the measurements. The factor four of loss in SA when comparing platinum bulk and Pt/C can largely...

  13. Selecting a Response in Task Switching: Testing a Model of Compound Cue Retrieval (United States)

    Schneider, Darryl W.; Logan, Gordon D.


    How can a task-appropriate response be selected for an ambiguous target stimulus in task-switching situations? One answer is to use compound cue retrieval, whereby stimuli serve as joint retrieval cues to select a response from long-term memory. In the present study, the authors tested how well a model of compound cue retrieval could account for a…

  14. Diallyl phthalate prepolymer characterization and testing in fiberglass filled molding compounds

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, R.B.; Schneider, R.E.; Schumacher, R.J.


    A program was undertaken to identify an acceptable alternative to Dapon 35, an o-diallyl phthalate (DAP) prepolymer no longer available. Three o-DAP prepolymers from the Osaka Soda Company and four laboratory-scale prepolymers from Bendix-Kansas city were characterized and evaluated in DAP-fiberglass molding compounds. Gel permeation chromatography results for the Osaka prepolymers showed all three to be very close to one another in molecular weights (mw) and mw distributions, but slightly lower in both than Dapon 35. They are also slightly higher in monomer content. All three processed readily into DAP-fiberglass molding compounds and passed required physical property tests. One Osaka prepolymer was compounded into both asbestos and Orlon-DAP compounds on a production scale. Both compounds have passed all certification tests. The Bendix prepolymers were deliberately varied in mw and mw distribution and higher in monomer content than Dapon 35. Processing difficulties were encountered with both the lowest and highest molecular weight compounds, and the lowest molecular weight compound failed a number of physical property tests. The two intermediate molecular weight compounds processed readily and passed property tests. Guidelines were established for acceptable o-DAP prepolymers: (1) weight average mw (relative to polystyrene standards): 30,000 to 150,000; (2) mw distribution: 3.0 to less than or equal to 18.0; and (3) DAP monomer content: 1.0 to less than or equal to 6.0%. 5 figures, 6 tables.

  15. Fabrication and Testing of High-Speed Single-Rotor and Compound-Rotor Systems (United States)


    Helicopters: Compounding the Quest for Speed,” Vertiflight, Summer 2006. 7. Spreuer, W.E. (1969) "Experimental Flight Tests of the XH-51A Compound...2000 mAh lithium ion polymer batteries (Sparkfun P/N PRT-08483)  One XBee Pro wireless transceiver with wire antenna (Sparkfun P/N WRL-10421)  One

  16. Fabrication and Testing of High-Speed-Single-Rotor and Compound-Rotor Systems (United States)


    Helicopters: Compounding the Quest for Speed,” Vertiflight, Summer 2006. 7. Spreuer, W.E. (1969) "Experimental Flight Tests of the XH-51A Compound...2000 mAh lithium ion polymer batteries (Sparkfun P/N PRT-08483)  One XBee Pro wireless transceiver with wire antenna (Sparkfun P/N WRL-10421)  One

  17. Comparative in vitro and in vivo pharmacological investigation of platinum(IV) complexes as novel anticancer drug candidates for oral application. (United States)

    Theiner, Sarah; Varbanov, Hristo P; Galanski, Markus; Egger, Alexander E; Berger, Walter; Heffeter, Petra; Keppler, Bernhard K


    Platinum(IV) complexes are promising candidates as prodrugs for oral application in anticancer chemotherapy. However, only a few Pt(IV) compounds entered (pre)clinical trials, e.g. satraplatin, while most of the others were only tested in vitro. Aim of the study was investigation of the in vivo pharmacological behavior as well as the anticancer activity of two novel platinum(IV) complexes vs. satraplatin. The drugs were selected due to significantly different in vitro cytotoxicity while sharing some physicochemical properties (e.g. lipophilicity). Initial experiments indicated that the highly in vitro cytotoxic compound 1 ((OC-6-33)-dichloridobis((4-ethoxy)-4-oxobutanoato)-bis(ethylamine)platinum(IV)) was also characterized by high drug absorption and tissue platinum levels after oral application. Interestingly, analysis of serum samples using SEC-ICP-MS revealed that the administered drugs have completely been metabolized and/or bound to proteins in serum within 2 h after treatment. With regard to the activity in vivo, the outcomes were rather unexpected: although potent anticancer effect of 1 was observed in cell culture, the effects in vivo were rather minor. Nevertheless, 1 was superior to 2 ((OC-6-33)-diammine(cyclobutane-1,1-dicarboxylato)-bis((4-cyclopentylamino)-4-oxobutanoato)platinum(IV)) after i.p. administration, which was, at least to some extent, in accordance to the cell culture experiments. After oral gavage, both compounds exhibited comparable activity. This is remarkable considering the distinctly lower activity of 2 in cell culture as well as the low platinum levels detected both in serum and tissues after oral application. Consequently, our data indicate that the prediction of in vivo anticancer activity by cell culture experiments is not trivial, especially for orally applied drugs.

  18. Platinum metals in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Zereini, Fathi [Frankfurt Univ. (Germany). Dept. of Environmental Analytical Chemistry; Wiseman, Clare L.S. (ed.) [Toronto Univ. (Canada). School of the Environment


    This book contains the five chapters with the following topics: 1. SOURCES OF PGE EMISSIONS ELEMENTS: Sources of Platinum Group Elements (PGE) in the Environment; Impact of Platinum Group Element Emissions from Mining and Production Activities. 2. ANALYTICAL METHODS FOR THE DETERMINATION OF PGE IN BIOLOGICAL AND ENVIRONMENTAL MATRICES: Appraisal of Biosorption for Recovery, Separation and Determination of Platinum, Palladium and Rhodium in Environmental Samples; On the Underestimated Factors Influencing the Accuracy of Determination of Pt and Pd by Electrothermal Atomic Absorption Spectrometry in Road Dust Samples; Application of Solid Sorbents for Enrichment and Separation of Platinum Metal Ions; Voltammetric Analysis of Platinum in Environmental Matrices; Speciation Analysis of Chloroplatinates; Analysis of Platinum Group Elements in Environmental Samples: A Review. 3. OCCURRENCE, CHEMICAL BEHAVIOR AND FATE OF PGE IN THE ENVIRONMENT: Brazilian PGE Research Data Survey on Urban and Roadside Soils; Platinum, Palladium and Rhodium in a Bavarian Roadside Soil; Increase of Platinum Group Element Concentrations in Soils and Airborne Dust During the Period of Vehicular Exhaust Catalysts Introduction; Platinum-Group Elements in Urban Fluvial Bed Sediments-Hawaii; Long-Term Monitoring of Palladium and Platinum Contents in Road Dust of the City of Munich, Germany; Characterization of PGEs and Other Elements in Road Dusts and Airborne Particles in Houston, Texas; Accumulation and Distribution of Pt and Pd in Roadside Dust, Soil and Vegetation in Bulgaria; Increase of the Environmental Pt Concentration in the Metropolitan Area of Mexico City Associated to the Use of Automobile Catalytic Converters; Solubility of Emitted Platinum Group Elements (Pt, Pd and Rh) in Airborne Particulate Matter (PM10) in the Presence of Organic Complexing Agents; The Influence of Anionic Species (Cl{sup -}, NO{sub 3}{sup -}, SO{sub 4}{sup 2-}) on the Transformation and Solubility of Platinum in

  19. Post-implantation embryo culture: validation with selected compounds for teratogenicity testing. (United States)

    Cicurel, L; Schmid, B P


    1. Some chemical compounds selected by experts for the validation of in vitro teratogenicity testing were investigated in whole rat embryos cultured during the early stages of organogenesis. All sixteen known in vivo teratogens tested also induced specific malformations in embryos grown in culture. 2. Of the nine compounds which were negative in in vivo rat teratogenicity studies, none provoked dysmorphogenic effects in cultured embryos. Abnormal development of the embryos was only observed with these compounds at concentrations also high enough to affect significantly overall growth and/or differentiation. 3. The results showed a high predictability of this system for the compounds tested and suggest that the post-implantation embryo culture system may also be useful in the prospective testing of new drugs and environmental chemicals.

  20. Internalization of Ineffective Platinum Complex in Nanocapsules Renders It Cytotoxic. (United States)

    Vrana, Oldrich; Novohradsky, Vojtech; Medrikova, Zdenka; Burdikova, Jana; Stuchlikova, Olga; Kasparkova, Jana; Brabec, Viktor


    Anticancer therapy by platinum complexes, based on nanocarrier-based delivery, may offer a new approach to improve the efficacy and tolerability of the platinum family of anticancer drugs. The original rules for the design of new anticancer platinum drugs were affected by the fact that, although cisplatin (cis-[PtCl2 (NH3)2) was an anticancer drug, its isomer transplatin was not cytotoxic. For the first time, it is demonstrated that simple encapsulation of an inactive platinum compound in phospholipid bilayers transforms it into an efficient cytotoxic agent. Notably, the encapsulation of transplatin makes it possible to overcome the resistance mechanisms operating in cancer cells treated with cisplatin and prevents inactivation of transplatin in the extracellular environment. It is also shown that transplatin delivered to the cells in nanocapsules, in contrast to free (nonencapsulated) complex, forms cytotoxic cross-links on DNA.

  1. Interfacial electronic effects control the reaction selectivity of platinum catalysts (United States)

    Chen, Guangxu; Xu, Chaofa; Huang, Xiaoqing; Ye, Jinyu; Gu, Lin; Li, Gang; Tang, Zichao; Wu, Binghui; Yang, Huayan; Zhao, Zipeng; Zhou, Zhiyou; Fu, Gang; Zheng, Nanfeng


    Tuning the electronic structure of heterogeneous metal catalysts has emerged as an effective strategy to optimize their catalytic activities. By preparing ethylenediamine-coated ultrathin platinum nanowires as a model catalyst, here we demonstrate an interfacial electronic effect induced by simple organic modifications to control the selectivity of metal nanocatalysts during catalytic hydrogenation. This we apply to produce thermodynamically unfavourable but industrially important compounds, with ultrathin platinum nanowires exhibiting an unexpectedly high selectivity for the production of N-hydroxylanilines, through the partial hydrogenation of nitroaromatics. Mechanistic studies reveal that the electron donation from ethylenediamine makes the surface of platinum nanowires highly electron rich. During catalysis, such an interfacial electronic effect makes the catalytic surface favour the adsorption of electron-deficient reactants over electron-rich substrates (that is, N-hydroxylanilines), thus preventing full hydrogenation. More importantly, this interfacial electronic effect, achieved through simple organic modifications, may now be used for the optimization of commercial platinum catalysts.

  2. The Effect of Β-casein Nanoparticles on Bioavailability and Cellular Uptake of Platinum Complex as a Cancer Drug

    Directory of Open Access Journals (Sweden)

    M Razmi


    Full Text Available Abstract Background & aim: Due to the low solubility and high toxicity of drugs, treatment of cancers is problematic therefore, the encapsulation and targeted delivery of therapeutic effect is required. The aim of this study was to investigate the effect of nanoparticles on cellular uptake and bioavailability of beta-casein on platinum complexes as cancer drugs. Methods: In the present experimental study, the physicochemical properties of nanoparticles as drug carriers of beta-casein devices using dynamic light scattering (DLS and scanning electron microscopy (SEM were investigated. In order to evaluate the toxicity effects of platinum complexes, the colon cancer cells in the absence or presence of free platinum complex concentration and nanoparticle loaded with platinum complexes were incubated for 24 and 48 hours. LD50 Values (concentration of compound causing 50% mortality in the cells was determined using the MTT assay. Data were analyzed by ANOVA and post-hoc test. Results: At a concentration of 1 mg ml, beta-casein nanoparticle drug carriers were synthesized in the range of 100 to 300 µM. In addition, the mortality rate in cancer cells by the release of platinum complexes (without and with the capsule, were 70 and 26 in 24 hours, and 60 µM and 21 µM in 48 hours respectively, Conclusion: The study showed that the bioavailability of the encapsulated platinum complexes increases and new drug delivery system may be a good candidate for the treatment of cancer. Key words: Beta-casein, Pt (II Complex, Bioavalibility, Nanocarrier, Micelle

  3. New Perfluorophtalate Complexes of Platinum(II) With Chemotherapeutic Potential


    de Oliveira, M. B.; J. Miller; Banks, R. E.; Kelland, L R; McAuliffe, C. A.; Mahmood, N; Rowland, I. J.


    Two new platinum(II) complexes have been synthesized and their anti-tumour and anti-HIV activities have been evaluated. The new complexes are: (i) cis-tetrafluorophthalate-ammine-morpholine-platinum(II) or MMF3 and (ii) cis-tetrafluorophthalate- ammine-piperidine-platinum(II) or MPF4. They were characterized by elemental analysis, IR spectra and 1H and 13C NMR spectra. They were tested against five human ovarian carcinoma cell lines, viz., CH1, CH1cisR, A2780, A2780cisR and SKOV-3. They were ...

  4. DFT-based QSAR and QSPR models of several cis-platinum complexes: solvent effect. (United States)

    Sarmah, Pubalee; Deka, Ramesh C


    Cytotoxic activities of cis-platinum complexes against parental and resistant ovarian cancer cell lines were investigated by quantitative structure-activity relationship (QSAR) analysis using density functional theory (DFT) based descriptors. The calculated parameters were found to increase the predictability of each QSAR model with incorporation of solvent effects indicating its importance in studying biological activity. Given the importance of logarithmic n-octanol/water partition coefficient (log P(o/w)) in drug metabolism and cellular uptake, we modeled the log P(o/w) of 24 platinum complexes with different leaving and carrier ligands by the quantitative structure-property relationship (QSPR) analysis against five different concentrations of MeOH using DFT and molecular mechanics derived descriptors. The log P(o/w) values of an additional set of 20 platinum complexes were also modeled with the same descriptors. We investigated the predictability of the model by calculating log P(o/w) of four compounds in the test set and found their predicted values to be in good agreement with the experimental values. The QSPR analyses performed on 24 complexes, combining the training and test sets, also provided significant values for the statistical parameters. The solvent medium played an important role in QSPR analysis by increasing the internal predictive ability of the models.

  5. Developmental toxicity of thyroid-active compounds in a zebrafish embryotoxicity test. (United States)

    Jomaa, Barae; Hermsen, Sanne A B; Kessels, Maurijn Y; van den Berg, Johannes H J; Peijnenburg, Ad A C M; Aarts, Jac M M J G; Piersma, Aldert H; Rietjens, Ivonne M C M


    Zebrafish embryos were exposed to concentration ranges of selected thyroid-active model compounds in order to assess the applicability of zebrafish-based developmental scoring systems withinan alternative testing strategy to detect the developmental toxicity ofthyroid-active compounds. Model compounds tested included triiodothyronine (T3), propylthiouracil (PTU), methimazole (MMI), sodium perchlorate (NaClO4) and amiodarone hydrochloride (AMI), selected to represent different modes of action affecting thyroid activity. Tested time windows included 48-120 hours post fertilization (hpf), 0-72 hpf and 0-120 hpf. All tested compounds resulted in developmental changes, with T3 being the most potent. The developmental parameters affected included reflective iridophores, beat and glide swimming, inflated swim bladders, as well as resorbed yolk sacs. These effects are only evident by 120 hpf and therefore an existing General Morphology Score (GMS) system was extended to create a General Developmental Score(GDS) that extends beyond the 72 hpfscoring limit of GMS and includes additional parameters that are affected by exposure to model thyroid-active compounds. Moreover, the GDS is cumulative as it includes not only the scoring of developmental morphologies but also integrates developmental dysmorphologies. Exposures from 48-120 hpf did not provide additional information to exposures from 0-120 hpf. The results indicate that the zebrafish GDS can detect the developmental toxicity of thyroid toxicants and may be of use in an integrated testing strategy to reduce, refine and in certain cases replace animal testing.

  6. 铂电阻温度计长期稳定性的试验研究%Study on the Long-term Stability Test for Platinum Resistance Thermometer

    Institute of Scientific and Technical Information of China (English)



    基于铂电阻温度计作为国际温标量值传递的计量标准器具,其长期稳定性对计量性能的重要性,提出了考核长期稳定性的加速老化试验公式和试验方法.以标准铂电阻温度计为试验对象,与自然存放、实际使用情况下的考核方法一起对其长期稳定性进行了试验研究.结果表明,加速老化试验方法可用于铂电阻温度计和其他温度计的长期稳定性的考核试验.三种不同的试验方法所引起的Rtp变化差异较小,加速老化试验引起Wzn的变化最大,可达到10mK.%As measurement standard instruments of quantity value transfer for ITS-90, the long-term stability of platinum resistance thermometer (PRT) is very important.This paper presents accelerated aging test formula and test method.The long-term stability was studied on standard platinum resistance thermometer (SPRT) with using accelerated aging test, test methods of the natural storage and under the condition of the actual usage .The results show that, the accelerated aging test method can be used to test the long-term stability of PRT or other thermometer. TheRtp changes little between the three different test methods,but the change of WZn reached 10mK that caused by the accelerated aging test.

  7. Interactions of skin thickness and physicochemical properties of test compounds in percutaneous penetration studies

    NARCIS (Netherlands)

    Wilkinson, S.C.; Maas, W.J.M.; Nielsen, J.B.; Greaves, L.C.; Sandt, J.J.M. van de; Williams, F.M.


    Objectives: To determine the effect of skin thickness on the percutaneous penetration and distribution of test compounds with varying physicochemical properties using in vitro systems. Studies were carried out in accordance with OECD guidelines on skin absorption tests. Methods: Percutaneous penetra

  8. Molding compound trends in a denser packaging world: Qualification tests and reliability concerns (United States)

    Nguyen, L. T.; Lo, R. H. Y.; Chen, A. S.; Belani, J. G.


    Molding compound development has traditionally been driven by the memory market, then subsequent applications filter down to other IC technologies such as logic, analog, and ASIC. However, this strategy has changed lately with the introduction of thin packages such as PQFP & TSOP. Rather than targeting a compound for a family of IC such as DRAM or SRAM, compound development efforts are now focused at specific classes of packages. The configurations of these thin packages impose new functional requirements that need to be revisited to provide the optimized combination of properties. The evolution of qualification tests mirrors the advances in epoxy and compounding technologies. From the first standard novolac-based epoxies of the 1970s to the latest 3(sup rd)-generation ultra-low stress materials, longer test times at increasingly harsher environments were achieved. This paper benchmarks the current reliability tests used by the electronic industry, examines those tests that affect and are affected by the molding compounds, discusses the relevance of accelerated testing, and addresses the major reliability issues facing current molding compound development efforts. Six compound-related reliability concerns were selected: moldability, package stresses, package cracking, halogen-induced intermetallic growth at bond pads, moisture-induced corrosion, and interfacial delamination. Causes of each failure type are surveyed and remedies are recommended. Accelerated tests are designed to apply to a limited quantity of devices, bias, or environmental conditions larger than usual ratings, to intensify failure mechanisms that would occur under normal operating conditions. The observed behavior is then extrapolated from the lot to the entire population. Emphasis is on compressing the time necessary to obtain reliability data. This approach has two main drawbacks. With increasingly complex devices, even accelerated tests are expensive. And with new technologies, it becomes

  9. Novel platinum(IV) complexes conjugated with a wogonin derivative as multi-targeted anticancer agents. (United States)

    Qin, Xiaodong; Xu, Gang; Chen, Feihong; Fang, Lei; Gou, Shaohua


    Platinum-based complexes like cisplatin and oxaliplatin are well known the mainstay of chemotherapy regimens on clinic. Wogonin, a natural product that possesses wide biological activities, is now in phase I clinical test as an anticancer agent in China. Herein reported are a series of novel Pt(IV) complexes that conjugated a wogonin derivative (compound 3) to the axial position via a linker group. After being tethered to the platinum(IV) complexes, the wogonin derivative provided multiple anticancer effects, especially in compound 10, a fusion containing wogonin and cisplatin units. Compound 10 not only inherited the genotoxicity from cisplatin, but also obtained the COX inhibitory property from the wogonin derivative. Further mechanistic investigation revealed that compound 10 caused the accumulation of ROS, decreased the mitochondrial membrane potential (ΔΨm) and then activated the p53 pathway. Overall, the research demonstrates that the "integrative" prodrug can be an effective strategy to promote the anticancer potency of Pt-based drugs for cancer treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. The toxicity of the quaternary ammonium compound benzalkonium chloride alone and in mixtures with other anionic compounds to bacteria in test systems with Vibrio fischeri and Pseudomonas putida. (United States)

    Sütterlin, H; Alexy, R; Kümmerer, K


    Mixtures of chemicals are present in the aquatic environment but standard testing methods assess only single compounds. One aspect of this question is the importance of the formation of ionic pairs, for example from quaternary ammonium compounds with organic anions, and the significance of the ionic pairs for bacterial toxicity in the aquatic environment. The aim of the present study was to investigate the toxicity of the cationic quaternary ammonium compound benzalkonium chloride (BAC) against aquatic bacteria in the presence of substances commonly found in wastewater, such as the anionic surfactant linear alkylbenzene sulfonate (LAS), naphthalene sulfonic acid (NSA), sodium dodecylsulfonate (SDS), and benzene sulfonic acid (BSA). The growth inhibition test with Pseudomonas putida and the Vibrio fischeri luminescent inhibition test were used to determine the toxicity of single compounds and compound mixtures. The results found in this study indicate that ion pair formation is of minor significance under the test conditions applied here.

  11. Platinum(II/IV) complexes containing ethylenediamine-N,N'-di-2/3-propionate ester ligands induced caspase-dependent apoptosis in cisplatin-resistant colon cancer cells. (United States)

    Kaluđerović, Goran N; Mijatović, Sanja A; Zmejkovski, Bojana B; Bulatović, Mirna Z; Gómez-Ruiz, Santiago; Mojić, Marija K; Steinborn, Dirk; Miljković, Djordje M; Schmidt, Harry; Stošić-Grujičić, Stanislava D; Sabo, Tibor J; Maksimović-Ivanić, Danijela D


    Several new R(2)eddp (R = i-Pr, i-Bu; eddp = ethylenediamine-N,N'-di-3-propionate) esters and corresponding platinum(ii) and platinum(iv) complexes of the general formula [PtCl(n)(R(2)edda-type)] (n = 2, 4) were synthesized and characterized by spectroscopic methods (IR, (1)H and (13)C NMR) and elemental analysis. The crystal structure of platinum(iv) complex [PtCl(4){(c-Pe)(2)eddip}] (3a) was resolved and is given herein. Ligand precursors, platinum(ii), and platinum(iv) complexes were tested against eight tumor cell lines (CT26CL25, HTC116, SW620, PC3, LNCaP, U251, A375, and B16). Selectivity in the action of those compounds between tumor and two normal primary cells (fibroblasts and keratinocytes) are discussed. A structure-activity relationship of these compounds is discussed. Furthermore, cell cycle distribution, induction of necrosis, apoptosis, autophagy, anoikis, caspase activation, ROS, and RNS are presented on the cisplatin-resistant colon carcinoma HCT116 cell line.

  12. Synthesis of Chlorinated Tetracyclic Compounds and Testing for Their Potential Antidepressant Effect in Mice

    Directory of Open Access Journals (Sweden)

    Usama Karama


    Full Text Available The synthesis of the tetracyclic compounds 1-(4,5-dichloro-9,10-dihydro-9,10-ethanoanthracen-11-yl-N-methylmethanamine (5 and 1-(1,8-dichloro-9,10-dihydro-9,10-ethanoanthracen-11-yl-N-methylmethanamine (6 as a homologue of the anxiolytic and antidepressant drugs benzoctamine and maprotiline were described. The key intermediate aldehydes (3 and (4 were successfully synthesized via a [4 + 2] cycloaddition between acrolein and 1,8-dichloroanthracene. The synthesized compounds were investigated for antidepressant activity using the forced swimming test. Compounds (5, (6 and (3 showed significant reduction in the mice immobility indicating significant antidepressant effects. These compounds significantly reduced the immobility times at a dose 80 mg/kg by 84.0%, 86.7% and 71.1% respectively.

  13. Platinum nitride with fluorite structure

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Rong; Zhang, Xiao-Feng


    The mechanical stability of platinum nitride has been studied using first-principles calculations. By calculating the single-crystal elastic constants, we show that platinum nitride can be stabilized in the fluorite structure, in which the nitrogen atoms occupy all the tetrahedral interstitial sites of the metal lattice. The stability is attributed to the pseudogap effect from analysis of the electronic structure.

  14. Comparison of Intracellular Stress Response of NCI-H526 Small Cell Lung Cancer (SCLC) Cells to Platinum(II) Cisplatin and Platinum(IV) Oxoplatin

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, Gerhard [Ludwig Boltzmann Cluster of Translational Oncology, A-1090 Vienna (Austria)


    In attempts to develop an orally applicable platinum-based drug, platinum(IV) drugs which exhibit higher in vivo stability compared to the platinum(II) drug cisplatin were formulated. The first such chemotherapeutic agent, namely satraplatin, failed to receive approval. In the present work, we checked the initial cellular stress response of the chemosensitive NCI-H526 small cell lung cancer (SCLC) cells by determination of the relative phosphorylation of 46 specific phosphorylation sites of 38 selected proteins in a six hours response to cisplatin (platinum(II)) or oxoplatin (platinum(IV)), respectively. Oxoplatin is considered as prodrug of cisplatin, although several findings point to differences in intracellular effects. Cisplatin induced hyperphosphorylation of p38α MAPK and AMPKα1, whereas oxoplatin treatment resulted in increased phosphorylation of a large number of signaling proteins involved in stress response/drug resistance, including JNK, GSK-3α, AMPKα1, src kinases, STATs, CHK-2 and especially focal adhesion kinase (FAK). Cisplatin exerts markedly higher cytotoxicity upon four hours short-term exposure in comparison to oxoplatin and, correspondingly, the extended initial stress response to the platinum(IV) drug oxoplatin thus is expected to increase clinical drug resistance. Induction of a substantial stress response to any prodrug of a platinum-based compound may likewise limit the effectivity of its active metabolite(s), such contributing to the failure of selected derivatized platinum complexes.

  15. Comparison of Intracellular Stress Response of NCI-H526 Small Cell Lung Cancer (SCLC Cells to Platinum(II Cisplatin and Platinum(IV Oxoplatin

    Directory of Open Access Journals (Sweden)

    Gerhard Hamilton


    Full Text Available In attempts to develop an orally applicable platinum-based drug, platinum(IV drugs which exhibit higher in vivo stability compared to the platinum(II drug cisplatin were formulated. The first such chemotherapeutic agent, namely satraplatin, failed to receive approval. In the present work, we checked the initial cellular stress response of the chemosensitive NCI-H526 small cell lung cancer (SCLC cells by determination of the relative phosphorylation of 46 specific phosphorylation sites of 38 selected proteins in a six hours response to cisplatin (platinum(II or oxoplatin (platinum(IV, respectively. Oxoplatin is considered as prodrug of cisplatin, although several findings point to differences in intracellular effects. Cisplatin induced hyperphosphorylation of p38α MAPK and AMPKα1, whereas oxoplatin treatment resulted in increased phosphorylation of a large number of signaling proteins involved in stress response/drug resistance, including JNK, GSK-3α, AMPKα1, src kinases, STATs, CHK-2 and especially focal adhesion kinase (FAK. Cisplatin exerts markedly higher cytotoxicity upon four hours short-term exposure in comparison to oxoplatin and, correspondingly, the extended initial stress response to the platinum(IV drug oxoplatin thus is expected to increase clinical drug resistance. Induction of a substantial stress response to any prodrug of a platinum-based compound may likewise limit the effectivity of its active metabolite(s, such contributing to the failure of selected derivatized platinum complexes.

  16. Thyroid in a jar: towards an integrated in vitro testing strategy for thyroid-active compounds

    NARCIS (Netherlands)

    Jomaa, B.


      Jomaa, B. (2015). Thyroid in a Jar: Towards an Integrated In Vitro Testing Strategy for Thyroid-Active Compounds. PhD thesis, Wageningen University, the Netherlands Abstract The aim of this thesis was to find in vitro and toxicogenomics-based alternatives to

  17. 21 CFR 862.1185 - Compound S (11-deoxycortisol) test system. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Compound S (11-deoxycortisol) test system. 862.1185 Section 862.1185 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry...


    NARCIS (Netherlands)


    The chemical stability of the new anticancer platinum analogue 1,2-diaminomethyl-cyclobutane-platinum(II)-lactate (D19466) in infusion media was studied in an accelerated stability testing experiment with a selective HPLC-UV method. Variables were time, temperature, light, concentration, and

  19. Theoretical investigations and density functional theory based quantitative structure-activity relationships model for novel cytotoxic platinum(IV) complexes. (United States)

    Varbanov, Hristo P; Jakupec, Michael A; Roller, Alexander; Jensen, Frank; Galanski, Markus; Keppler, Bernhard K


    Octahedral platinum(IV) complexes are promising candidates in the fight against cancer. In order to rationalize the further development of this class of compounds, detailed studies on their mechanisms of action, toxicity, and resistance must be provided and structure-activity relationships must be drawn. Herein, we report on theoretical and QSAR investigations of a series of 53 novel bis-, tris-, and tetrakis(carboxylato)platinum(IV) complexes, synthesized and tested for cytotoxicity in our laboratories. The hybrid DFT functional wb97x was used for optimization of the structure geometry and calculation of the descriptors. Reliable and robust QSAR models with good explanatory and predictive properties were obtained for both the cisplatin sensitive cell line CH1 and the intrinsically cisplatin resistant cell line SW480, with a set of four descriptors.

  20. Anticancer Platinum(IV) Prodrugs Containing Monoaminophosphonate Ester as a Targeting Group Inhibit Matrix Metalloproteinases and Reverse Multidrug Resistance. (United States)

    Huang, Xiaochao; Huang, Rizhen; Gou, Shaohua; Wang, Zhimei; Wang, Hengshan


    A novel class of platinum(IV) complexes comprising a monoaminophosphonate ester moiety, which can not only act as a bone-targeting group but also inhibit matrix metalloproteinases (MMPs), were designed and synthesized. Biological assay of these compounds showed that they had potent antitumor activities against the tested cancer cell lines compared with cisplatin and oxaliplatin and indicated low cytotoxicity to human normal liver cells. Particularly, the platinum(IV) complexes were very sensitive to cisplatin resistant cancer cell lines. The corresponding structure-activity relationships were studied and discussed. Related mechanism study revealed that the typical complex 11 caused cell cycle arrest at S phase and induced apoptosis in Bel-7404 cells via a mitochondrial-dependent apoptosis pathway. Moreover, complex 11 had potent ability to inhibit the tumor growth in the NCI-H460 xenograft model comparable to cisplatin.

  1. Theoretical Investigations and Density Functional Theory Based Quantitative Structure–Activity Relationships Model for Novel Cytotoxic Platinum(IV) Complexes (United States)


    Octahedral platinum(IV) complexes are promising candidates in the fight against cancer. In order to rationalize the further development of this class of compounds, detailed studies on their mechanisms of action, toxicity, and resistance must be provided and structure–activity relationships must be drawn. Herein, we report on theoretical and QSAR investigations of a series of 53 novel bis-, tris-, and tetrakis(carboxylato)platinum(IV) complexes, synthesized and tested for cytotoxicity in our laboratories. The hybrid DFT functional wb97x was used for optimization of the structure geometry and calculation of the descriptors. Reliable and robust QSAR models with good explanatory and predictive properties were obtained for both the cisplatin sensitive cell line CH1 and the intrinsically cisplatin resistant cell line SW480, with a set of four descriptors. PMID:23214999

  2. Standard test method for determining plutonium by controlled-potential coulometry in H2SO4 at a platinum working electrode

    CERN Document Server

    American Society for Testing and Materials. Philadelphia


    1.1 This test method covers the determination of milligram quantities of plutonium in unirradiated uranium-plutonium mixed oxide having a U/Pu ratio range of 0.1 to 10. This test method is also applicable to plutonium metal, plutonium oxide, uranium-plutonium mixed carbide, various plutonium compounds including fluoride and chloride salts, and plutonium solutions. 1.2 The recommended amount of plutonium for each aliquant in the coulometric analysis is 5 to 10 mg. Precision worsens for lower amounts of plutonium, and elapsed time of electrolysis becomes impractical for higher amounts of plutonium. 1.3 The values stated in SI units are to be regarded as standard. No other units are to be regarded as standard. 1.4 This standard does not purport to address all of the safety concens, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precaution...


    This report presents the results of the verification test of the Sharpe Platinum 2013 high-volume, low-pressure gravity-feed spray gun, hereafter referred to as the Sharpe Platinum, which is designed for use in automotive refinishing. The test coating chosen by Sharpe Manufacturi...


    This report presents the results of the verification test of the Sharpe Platinum 2013 high-volume, low-pressure gravity-feed spray gun, hereafter referred to as the Sharpe Platinum, which is designed for use in automotive refinishing. The test coating chosen by Sharpe Manufacturi...

  5. Lap Shear and Impact Testing of Ochre and Beeswax in Experimental Middle Stone Age Compound Adhesives. (United States)

    Kozowyk, P R B; Langejans, G H J; Poulis, J A


    The production of compound adhesives using disparate ingredients is seen as some of the best evidence of advanced cognition outside of the use of symbolism. Previous field and laboratory testing of adhesives has shown the complexities involved in creating an effective Middle Stone Age glue using Acacia gum. However, it is currently unclear how efficient different adhesive recipes are, how much specific ingredients influence their performance, and how difficult it may have been for those ingredients to be combined to maximum effect. We conducted a series of laboratory-based lap shear and impact tests, following modern adhesion testing standards, to determine the efficacy of compound adhesives, with particular regard to the ingredient ratios. We tested rosin (colophony) and gum adhesives, containing additives of beeswax and ochre in varying ratios. During both lap shear and impact tests compound rosin adhesives performed better than single component rosin adhesives, and pure acacia gum was the strongest. The large difference in performance between each base adhesive and the significant changes in performance that occur due to relatively small changes in ingredient ratios lend further support to the notion that high levels of skill and knowledge were required to consistently produce the most effective adhesives.

  6. Lap Shear and Impact Testing of Ochre and Beeswax in Experimental Middle Stone Age Compound Adhesives.

    Directory of Open Access Journals (Sweden)

    P R B Kozowyk

    Full Text Available The production of compound adhesives using disparate ingredients is seen as some of the best evidence of advanced cognition outside of the use of symbolism. Previous field and laboratory testing of adhesives has shown the complexities involved in creating an effective Middle Stone Age glue using Acacia gum. However, it is currently unclear how efficient different adhesive recipes are, how much specific ingredients influence their performance, and how difficult it may have been for those ingredients to be combined to maximum effect. We conducted a series of laboratory-based lap shear and impact tests, following modern adhesion testing standards, to determine the efficacy of compound adhesives, with particular regard to the ingredient ratios. We tested rosin (colophony and gum adhesives, containing additives of beeswax and ochre in varying ratios. During both lap shear and impact tests compound rosin adhesives performed better than single component rosin adhesives, and pure acacia gum was the strongest. The large difference in performance between each base adhesive and the significant changes in performance that occur due to relatively small changes in ingredient ratios lend further support to the notion that high levels of skill and knowledge were required to consistently produce the most effective adhesives.

  7. Laboratory testing and modeling to evaluate perfluorocarbon compounds as tracers in geothermal systems

    Energy Technology Data Exchange (ETDEWEB)

    Reimus, Paul W [Los Alamos National Laboratory


    The thermal stability and adsorption characteristics of three perfluorinated hydrocarbon compounds were evaluated under geothermal conditions to determine the potential to use these compounds as conservative or thermally-degrading tracers in Engineered (or Enhanced) Geothermal Systems (EGS). The three compounds tested were perfluorodimethyl-cyclobutane (PDCB), perfluoromethylcyclohexane (PMCH), and perfluorotrimethylcyclohexane (PTCH), which are collectively referred to as perfluorinated tracers, or PFTs. Two sets of duplicate tests were conducted in batch mode in gold-bag reactors, with one pair of reactors charged with a synthetic geothermal brine containing the PFTs and a second pair was charged with the brine-PFT mixture plus a mineral assemblage chosen to be representative of activated fractures in an EGS reservoir. A fifth reactor was charged with deionized water containing the three PFTs. The experiments were conducted at {approx}100 bar, with temperatures ranging from 230 C to 300 C. Semi-analytical and numerical modeling was also conducted to show how the PFTs could be used in conjunction with other tracers to interrogate surface area to volume ratios and temperature profiles in EGS reservoirs. Both single-well and cross-hole tracer tests are simulated to illustrate how different suites of tracers could be used to accomplish these objectives. The single-well tests are especially attractive for EGS applications because they allow the effectiveness of a stimulation to be evaluated without drilling a second well.

  8. Assessment of embryotoxicity of compounds in cosmetics by the embryonic stem cell test. (United States)

    Chen, Rui; Chen, Jing; Cheng, Shujun; Qin, Jie; Li, Weiqiang; Zhang, Lirong; Jiao, Hong; Yu, Xinbing; Zhang, Xiuming; Lahn, Bruce T; Xiang, Andy Peng


    The new EU legislations for cosmetics (Seventh Amendment) have laid down deadlines for the replacement of animal tests in cosmetics. This policy stimulates the acceptance of in vitro approaches to test embryotoxic potentials of compounds in cosmetics products. The embryonic stem cell test (EST) designed by The European Centre for the Validation of Alternative Methods (ECVAM) is currently the most promising in vitro assay to predict the embryotoxic potential of compounds. In this study, six selected compounds (hydroquinone, eugenol, dibutyl phthalate, antimony (III) oxide, neodymium (III) nitrate hydrate, melamine) formerly involved in cosmetic products were selected to test their embryotoxic potentials by the EST. 5-Fluorouracil and penicillin G were separately set as positive and negative control. The embryotoxic potential was determined by the prediction model (PM), which was calculated from three endpoints, the IC(50) 3T3, IC(50) ES, and ID(50). Hydroquinone, eugenol, and antimony (III) oxide indicated with strong embryotoxicity, while dibutyl phthalate, neodymium (III) nitrate hydrate, and melamine exhibited a weak embryotoxicity. These results may provide a valuable attempt to expand the application of EST to the cosmetics field.

  9. Dinuclear Pt(II)-bisphosphonate complexes: a scaffold for multinuclear or different oxidation state platinum drugs. (United States)

    Piccinonna, Sara; Margiotta, Nicola; Pacifico, Concetta; Lopalco, Antonio; Denora, Nunzio; Fedi, Serena; Corsini, Maddalena; Natile, Giovanni


    Geminal bisphosphonates (BPs), used in the clinic for the treatment of hypercalcaemia and skeletal metastases, have been also exploited for promoting the specific accumulation of platinum antitumor drugs in bone tissue. In this work, the platinum dinuclear complex [{Pt(en)}(2)(μ-AHBP-H(2))](+) (1) (the carbon atom bridging the two phosphorous atoms carrying a 2-ammonioethyl and a hydroxyl group, AHBP-H(2)) has been used as scaffold for the synthesis of a Pt(II) trinuclear complex, [{Pt(en)}(3)(μ-AHBP)](+) (2), and a Pt(IV) adamantane-shaped dinuclear complex featuring an oxo-bridge, [{Pt(IV)(en)Cl}(2)(μ-O)(μ-AHBP-H(2))](+) (3) (X-ray structure). Compound 2 undergoes a reversible, pH dependent, rearrangement with a neat switch point around pH = 5.4. Compound 3 undergoes a one-step electrochemical reduction at E(pc) = -0.84 V affording compound 1. Such a potential is far lower than that of glutathione (-0.24 V), nevertheless compound 3 can undergo chemical reduction to 1 by GSH, most probably through a different (inner-sphere) mechanism. In vitro cytotoxicity of the new compounds, tested against murine glioma (C6) and human cervix (HeLa) and hepatoma (HepG2) cell lines, has shown that, while the Pt(IV) dimer 3 is inactive up to a concentration of 50 μM, the two Pt(II) polynuclear compounds 1 and 2 have a cytotoxicity comparable to that of cisplatin with the trinuclear complex 2 generally more active than the dinuclear complex 1.

  10. Platinum (II) and (IV) spermidine complexes. Synthesis, characterization, and biological studies. (United States)

    Navarro-Ranninger, C; Ochoa, P A; Pérez, J M; González, V M; Masaguer, J R; Alonso, C


    By reaction of K2PtCl4 with spermidine we have synthesized two tris-platinum covalent compounds of formula (PtI2)3(sper)2 and (PtCl2)3(sper)2, one ionic compound of formula (sperH3)2(PtCl4)3, and another one of a covalent nature of formula (PtCl2sperH)2 (PtCl4) having a partially protonated spermidine residue. Treatment of the tris-platinum compounds with hydrogen peroxide and hydrochloric acid led to the production of two compounds of formula cis-trans-cis-(PtIVCl2(OH)2)3(sper)2 and cis-(PtIVCl4)3(sper)2, respectively. All of them have been characterized by IR and 1H MNR spectroscopy and tested for their ability to interact with pUC8 plasmid DNA by the use of UV, CD, and electrophoretic techniques. The results suggest that all of these compounds modify the secondary structure of the double helix. We observed that the alteration in electrophoretic mobility of nicked and closed circular forms of DNA induced by the Pt(II) complexes is higher than that induced by the Pt(IV) complexes. The synthesized compounds were also assayed for antitumor activity in vitro against breast (MDA-MB468) and leukemia (HL-60) tumor cells. Only three of these complexes may be regarded as potential antitumor agents, since their ID50 values are lower than 10 micrograms/ml.

  11. Determination of platinum traces contamination by graphite furnace atomic absorption spectrometry after preconcentration by cloud point extraction

    Energy Technology Data Exchange (ETDEWEB)

    Chappuy, M. [Analytical Development Laboratory, Pharmaceutical Establishment of Paris Hospitals, 7 rue du Fer a Moulin, 75005 Paris (France); Caudron, E., E-mail: [Analytical Development Laboratory, Pharmaceutical Establishment of Paris Hospitals, 7 rue du Fer a Moulin, 75005 Paris (France); Groupe de Chimie Analytique de Paris-Sud, EA 4041, IFR 141, School of Pharmacy, Univ Paris-Sud, 92296 Chatenay-Malabry (France); Bellanger, A. [Department of Pharmacy, Pitie-Salpetriere Hospital (Paris Public Hospital Authority), 47 boulevard de l' hopital, 75013 Paris (France); Pradeau, D. [Analytical Development Laboratory, Pharmaceutical Establishment of Paris Hospitals, 7 rue du Fer a Moulin, 75005 Paris (France)


    A simple and sensitive method is described for the determination of platinum surface contamination originating from cisplatin, carboplatin and oxaliplatin. Following extraction from swabs and preconcentration with the cloud point extraction (CPE) method, detection was by graphite furnace atomic absorption spectrometry (GFAAS). After desorption of platinum compounds from the swab, CPE involved on preconcentration of platinum in aqueous solution with diethyldithiocarbamate (DDTC) as chelating agent and Triton X-114 as extraction medium. DDTC is not only a chelating agent, but may also be a good candidate for the inactivation of platinum compounds. DDTC is recommended by the Word Health Organization (WHO) for the destruction of platinum-based anticancer drugs. The main factors affecting CPE efficiency, pH of the sample solution, concentrations of DDTC and Triton X-114, equilibration temperature and incubation time, were evaluated in order to enhance sensitivity of the method. The desorption of platinum compounds from the swab was investigated in parallel. Since platinum is bound to DDTC, it must exchange with copper in order to enhance platinum atomizing by GFAAS. A preconcentration factor of 29 was obtained for 10 mL of a platinum solution at 10 {mu}g mL{sup -1}. In optimal conditions, the limit of detection was 0.2 ng mL{sup -1}, corresponding to 2.0 ng of platinum metal on the swab. Absorbance was linear between 0.7 and 15 ng mL{sup -1}. The proposed method was applied for the determination of surface contamination by platinum compounds with correct results.

  12. Platinum nanoparticles induce damage to DNA and inhibit DNA replication (United States)

    Nejdl, Lukas; Kudr, Jiri; Moulick, Amitava; Hegerova, Dagmar; Ruttkay-Nedecky, Branislav; Gumulec, Jaromir; Cihalova, Kristyna; Smerkova, Kristyna; Dostalova, Simona; Krizkova, Sona; Novotna, Marie; Kopel, Pavel


    Sparsely tested group of platinum nanoparticles (PtNPs) may have a comparable effect as complex platinum compounds. The aim of this study was to observe the effect of PtNPs in in vitro amplification of DNA fragment of phage λ, on the bacterial cultures (Staphylococcus aureus), human foreskin fibroblasts and erythrocytes. In vitro synthesized PtNPs were characterized by dynamic light scattering (PtNPs size range 4.8–11.7 nm), zeta potential measurements (-15 mV at pH 7.4), X-ray fluorescence, UV/vis spectrophotometry and atomic absorption spectrometry. The PtNPs inhibited the DNA replication and affected the secondary structure of DNA at higher concentrations, which was confirmed by polymerase chain reaction, DNA sequencing and DNA denaturation experiments. Further, cisplatin (CisPt), as traditional chemotherapy agent, was used in all parallel experiments. Moreover, the encapsulation of PtNPs in liposomes (LipoPtNPs) caused an approximately 2.4x higher of DNA damage in comparison with CisPt, LipoCisPt and PtNPs. The encapsulation of PtNPs in liposomes also increased their antibacterial, cytostatic and cytotoxic effect, which was determined by the method of growth curves on S. aureus and HFF cells. In addition, both the bare and encapsulated PtNPs caused lower oxidative stress (determined by GSH/GSSG ratio) in the human erythrocytes compared to the bare and encapsulated CisPt. CisPt was used in all parallel experiments as traditional chemotherapy agent. PMID:28704436

  13. Understanding platinum-induced ototoxicity. (United States)

    Langer, Thorsten; am Zehnhoff-Dinnesen, Antoinette; Radtke, Susanne; Meitert, Johannes; Zolk, Oliver


    Childhood cancer survival rates are now nearly 80% in more developed European countries because of improved therapies and better supportive care. Platinum chemotherapy drugs, such as cisplatin and carboplatin, are the cornerstone of many effective therapeutic protocols for childhood cancer. However, the antitumor efficacy of cisplatin and carboplatin comes at the cost of ototoxicity, which affects at least 60% of pediatric patients. Although ototoxicity is not life threatening, it can have debilitating effects on patients' quality of life. Recently, many initiatives have been launched with the ultimate goal of reducing cisplatin and high-dose carboplatin ototoxicity without compromising antitumor efficacy. This review addresses the incidence of platinum ototoxicity and its clinical presentation, time course, and early diagnostic evaluation. Genetic and non-genetic risk factors for platinum-associated ototoxicity, and their predictive value, are discussed. Recent developments in the prevention of platinum ototoxicity are also summarized. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Uptake of platinum by zebrafish (Danio rerio) and ramshorn snail (Marisa cornuarietis) and resulting effects on early embryogenesis. (United States)

    Osterauer, Raphaela; Haus, Nadine; Sures, Bernd; Köhler, Heinz-R


    Platinum group elements (PGEs), platinum, palladium and rhodium are widely used in automobile catalytic converters. PGEs are emitted into the environment and enter the aquatic ecosystem via runoff rainwater. The present study investigated the bioavailability of platinum chloride for the zebrafish (Danio rerio) and the ramshorn snail (Marisa cornuarietis) and determined the bioaccumulation rate of platinum. Applying the fish early life stage assay for D. rerio (DarT) and the Marisa embryo toxicity test ("Mariett") for M. cornuarietis, effects of platinum chloride on the embryonic development were investigated. Platinum concentrations tested in this study ranged from environmentally relevant concentrations of 38 ng L(-1) up to a concentration of 74.2 microg L(-1) for D. rerio and of 200 ngL(-1) up to 98.7 microg L(-1) for M. cornuarietis. Platinum was found to be accumulated in both organisms. Bioaccumulation factors (BAFs) were in the range of 5-55 for D. rerio and of 218.4-723.9 for M. cornuarietis, depending on the tested Pt concentrations. During the embryonic development, platinum was shown to alter the heart rate of both organisms already at the lowest tested concentration. At higher concentrations, platinum decelerated the hatching rate of the embryos of both species. Additionally, a retardation of the general development and a loss of weight due to platinum exposure was observed in M. cornuarietis. Results of this study contribute important data on the ecotoxicity of a rarely studied element.

  15. Presentation and Diagnosis of Hypersensitivity to Platinum Drugs. (United States)

    Caiado, Joana; Castells, Mariana


    Hypersensitivity reactions (HSRs) to platinum drugs are increasing due to their extensive use in a wide variety of malignancies and the repeated exposures in patients with increased life expectancy. Understanding the incidence of HSR to platinum drugs and associated risk factors can help with the diagnosis and may provide protection against severe HSRs. A thorough clinical history with identification of the typical and atypical symptoms, the relationship with the platin administration, and the number of previous exposures are the key to the diagnosis. An elevated serum tryptase at the time of the HSR indicates that IgE and/or mast cells/basophils were involved in the HSR. Skin testing to platinum drugs is a highly sensitive and specific diagnostic tool, which helps provide risk stratification and management recommendations. Platinum specific IgE measurement and basophil activation test (BAT) are emerging as new diagnostic tools and in combination with skin testing can help support the diagnosis and the cross-reactivity between the three most commonly used platinum drugs, namely carboplatin, cisplatin, and oxaliplatin.

  16. Compounding diagnostic delays: a qualitative study of point-of-care testing in South Africa. (United States)

    Engel, Nora; Davids, Malika; Blankvoort, Nadine; Pai, Nitika Pant; Dheda, Keertan; Pai, Madhukar


    Successful point-of-care (POC) testing (completion of test-and-treat cycle in one patient encounter) has immense potential to reduce diagnostic and treatment delays, and improve patient and public health outcomes. We explored what tests are done and how in public/private, rural/urban hospitals and clinics in South Africa and whether they can ensure successful POC testing. This qualitative research study examined POC testing across major diseases in Cape Town, Durban and Eastern Cape. We conducted 101 semi-structured interviews and seven focus group discussions with doctors, nurses, community health workers, patients, laboratory technicians, policymakers, hospital managers and diagnostic manufacturers. In South Africa, diagnostics are characterised by a centralised system. Most tests conducted on the spot can be made to work successfully as POC tests. The majority of public/private clinics and smaller hospitals send samples via couriers to centralised laboratories and retrieve results the same way, via internet, fax or phone. The main challenge to POC testing lies in transporting samples and results, while delays risk patient loss from diagnostic/treatment pathways. Strategies to deal with associated delays create new problems, such as artificially prolonged turnaround times, strains on human resources and quality of testing, compounding additional diagnostic and treatment delays. For POC testing to succeed, particular characteristics of diagnostic ecosystems and adaptations of professional practices to overcome associated challenges must be taken into account. © 2014 John Wiley & Sons Ltd.

  17. Selective speciation improves efficacy and lowers toxicity of platinum anticancer and vanadium antidiabetic drugs. (United States)

    Doucette, Kaitlin A; Hassell, Kelly N; Crans, Debbie C


    Improving efficacy and lowering resistance to metal-based drugs can be addressed by consideration of the coordination complex speciation and key reactions important to vanadium antidiabetic drugs or platinum anticancer drugs under biological conditions. The methods of analyses vary depending on the specific metal ion chemistry. The vanadium compounds interconvert readily, whereas the reactions of the platinum compounds are much slower and thus much easier to study. However, the vanadium species are readily differentiated due to vanadium complexes differing in color. For both vanadium and platinum systems, understanding the processes as the compounds, Lipoplatin and Satraplatin, enter cells is needed to better combat the disease; there are many cellular metabolites, which may affect processing and thus the efficacy of the drugs. Examples of two formulations of platinum compounds illustrate how changing the chemistry of the platinum will result in less toxic and better tolerated drugs. The consequence of the much lower toxicity of the drug, can be readily realized because cisplatin administration requires hospital stay whereas Lipoplatin can be done in an outpatient manner. Similarly, the properties of Satraplatin allow for development of an oral drug. These forms of platinum demonstrate that the direct consequence of more selective speciation is lower side effects and cheaper administration of the anticancer agent. Therefore we urge that as the community goes forward in development of new drugs, control of speciation chemistry will be considered as one of the key strategies in the future development of anticancer drugs.

  18. Inorganic nanocarriers for platinum drug delivery

    Directory of Open Access Journals (Sweden)

    Ping’an Ma


    Full Text Available Nowadays platinum drugs take up almost 50% of all the clinically used anticancer drugs. Besides cisplatin, novel platinum agents including sterically hindered platinum (II drugs, chemically reductive platinum (IV drugs, photosensitive platinum (IV drugs, and multinuclear platinum drugs have been developed recently, with a few entering clinic trials. Rapid development of nanobiotechnology makes targeted delivery of anticancer platinum agents to the tumor site possible, while simultaneously minimizing toxicity and maximizing the drug efficacy. Being versatile drug carriers to deliver platinum drugs, inorganic nanovehicles such as gold nanoparticles, iron oxide nanomaterials, carbon nanotubes, mesoporous nanosilica, metal-organic frameworks (MOFs, have been extensively studied over the past decades. In contrast to conventional polymeric and lipid nanoparticles, inorganic nanoparticles based drug carriers are peculiar as they have shown excellent theranostic effects, revealing themselves an indispensable part of future nanomedicine. Here, we will elaborate recent research advances on fabrication of inorganic nanoparticles for platinum drug delivery.

  19. Platinum availability for future automotive technologies. (United States)

    Alonso, Elisa; Field, Frank R; Kirchain, Randolph E


    Platinum is an excellent catalyst, can be used at high temperatures, and is stable in many aggressive chemical environments. Consequently, platinum is used in many current industrial applications, notably automotive catalytic converters, and prospective vehicle fuel cells are expected to rely upon it. Between 2005 and 2010, the automotive industry used approximately 40% of mined platinum. Future automotive industry growth and automotive sales shifts toward new technologies could significantly alter platinum demand. The potential risks for decreased platinum availability are evaluated, using an analysis of platinum market characteristics that describes platinum's geophysical constraints, institutional efficiency, and dynamic responsiveness. Results show that platinum demand for an automotive fleet that meets 450 ppm greenhouse gas stabilization goals would require within 10% of historical growth rates of platinum supply before 2025. However, such a fleet, due largely to sales growth in fuel cell vehicles, will more strongly constrain platinum supply in the 2050 time period. While current platinum reserves are sufficient to satisfy this increased demand, decreasing platinum ore grade and continued concentration of platinum supply in a single geographic area are availability risk factors to platinum end-users.

  20. Platinum Complexes with Edda (Ethylenediamine -N, N - Diacetate Ligands as Potential Anticancer Agents

    Directory of Open Access Journals (Sweden)

    Jurisevic Milena


    Full Text Available The design of platinum based drugs is not a new field of interest. Platinum complexes are widely used as anticancer agents and currently, approximately 30 platinum(II and platinum(IV entered into some of the phases of clinical trials. A special place in today’s research belongs to platinum complexes with diammine ligands. A large number of edda (ethylenediamine- N, N’-diacetate-type ligands and their corresponding metal complexes has been successfully synthesized. This article summarizes recent progress in research on edda-type-platinum complexes. Some of these agents achieves better effect compared to the gold standard (cisplatin. It has been shown that there is a possible relationship between the length of the ligand ester group carbon chain and its cytotoxic effect. In most cases the longer the ester chain is the greater is the antitumor activity. Of particular interest are the noticeable effects of some new platinum compound with edda-type ligand on cell lines that are known to have a high level of cisplatin-resistance. Exanimate complexes appear to have a different mode of mechanism of action compared with cisplatin which includes apoptotic and necrotic cell death. There are indications that further investigations of these compounds may be very useful in overcoming the problems associated global cancer statistic.

  1. The Next Generation of Platinum Drugs: Targeted Pt(II) Agents, Nanoparticle Delivery, and Pt(IV) Prodrugs. (United States)

    Johnstone, Timothy C; Suntharalingam, Kogularamanan; Lippard, Stephen J


    The platinum drugs, cisplatin, carboplatin, and oxaliplatin, prevail in the treatment of cancer, but new platinum agents have been very slow to enter the clinic. Recently, however, there has been a surge of activity, based on a great deal of mechanistic information, aimed at developing nonclassical platinum complexes that operate via mechanisms of action distinct from those of the approved drugs. The use of nanodelivery devices has also grown, and many different strategies have been explored to incorporate platinum warheads into nanomedicine constructs. In this Review, we discuss these efforts to create the next generation of platinum anticancer drugs. The introduction provides the reader with a brief overview of the use, development, and mechanism of action of the approved platinum drugs to provide the context in which more recent research has flourished. We then describe approaches that explore nonclassical platinum(II) complexes with trans geometry or with a monofunctional coordination mode, polynuclear platinum(II) compounds, platinum(IV) prodrugs, dual-threat agents, and photoactivatable platinum(IV) complexes. Nanoparticles designed to deliver platinum(IV) complexes will also be discussed, including carbon nanotubes, carbon nanoparticles, gold nanoparticles, quantum dots, upconversion nanoparticles, and polymeric micelles. Additional nanoformulations, including supramolecular self-assembled structures, proteins, peptides, metal-organic frameworks, and coordination polymers, will then be described. Finally, the significant clinical progress made by nanoparticle formulations of platinum(II) agents will be reviewed. We anticipate that such a synthesis of disparate research efforts will not only help to generate new drug development ideas and strategies, but also will reflect our optimism that the next generation of approved platinum cancer drugs is about to arrive.

  2. Platinum(iv) N-heterocyclic carbene complexes: their synthesis, characterisation and cytotoxic activity. (United States)

    Bouché, M; Dahm, G; Wantz, M; Fournel, S; Achard, T; Bellemin-Laponnaz, S


    Platinum(ii) N-heterocyclic carbene complexes have been oxidized by bromine or iodobenzene dichloride to provide the fully characterised corresponding platinum(iv) NHC complexes. Antiproliferative activities of Pt(iv) NHC complexes were assayed against several cancer cell lines and the results were correlated with respect to their stability. Mechanistic investigations revealed that mitochondrial dysfunction and ROS production were associated with the cytotoxic process induced by these compounds.


    Directory of Open Access Journals (Sweden)

    Bhupendra Singh


    Full Text Available In this paper,a reliability sampling plan is developed assuming that lifetimes of the test units follow compound Rayleigh distribution and the life test is terminated at a pre-fixed time. This type of sampling plan is used to save the test time in practical situations. The minimum sample size required for ensuringthe specified mean life at specified consumer’s confidence level has been determined. The operating characteristic curve values of the sampling plans are examined with varying ratio of the true mean life to the specified life. The minimum such mean ratios are also obtained to minimize the producer’s risk at the specified level. For illustrative purpose, a numerical example has been discussed.

  4. Antitumor activities and interaction with DNA of oxaliplatin-type platinum complexes with linear or branched alkoxyacetates as leaving groups. (United States)

    Yin, Runting; Gou, Shaohua; Liu, Xia; Lou, Liguang


    Five oxaliplatin-typed platinum complexes containing trans-1R, 2R-diaminocyclohexane chelating platinum cores, characteristic of linear or branched alkoxycarboxylates as leaving groups, were biologically evaluated. These compounds showed higher antitumor activity, lower toxicity in vivo than cisplatin or oxaliplatin. And the results revealed that the antitumor activity and interaction with DNA of these compounds were highly related to the nature of leaving groups. Among these complexes, 5a, cis-(trans-1R, 2R-diaminocyclohexane) bis (2-tert-butoxyacetate) platinum(II), showed the highest antitumor activity and the lowest toxicity.

  5. In vivo and in vitro testing for selenium and selenium compounds bioavailability assessment in foodstuff. (United States)

    Moreda-Piñeiro, Jorge; Moreda-Piñeiro, Antonio; Bermejo-Barrera, Pilar


    The assessment of selenium and selenium species bioavailability in foodstuff is of special concern on the context of human nutrition. In vivo (human and animal), and in vitro tests are important approaches for estimating the bioavailability of toxic and essential compounds to humans. An overview on in vivo and in vitro bioavailability assays for releasing selenium and selenium species in foodstuffs is summarized. Se and Se species content in a foodstuff critically influence Se bioavailability and bioactivity to humans and animals. Se bioavailability is affected by foodstuff-matrix major composition and minor components. Foodstuffs processing and/or treatments could enhancement or decrease Se bioavailability. Experimental conditions such as the selection of healthy status of examined people (in in vivo humans approaches), the selection of animal model (in vivo animals approaches), or the selection of GI conditions (in in vitro tests) could determines the results. Thus, international standardized protocol for in vivo and in vitro approaches assessment is mandatory.

  6. Production integrated nondestructive testing of composite materials and material compounds – an overview (United States)

    Straß, B.; Conrad, C.; Wolter, B.


    Composite materials and material compounds are of increasing importance, because of the steadily rising relevance of resource saving lightweight constructions. Quality assurance with appropriate Nondestructive Testing (NDT) methods is a key aspect for reliable and efficient production. Quality changes have to be detected already in the manufacturing flow in order to take adequate corrective actions. For materials and compounds the classical NDT methods for defectoscopy, like X-ray and Ultrasound (US) are still predominant. Nevertheless, meanwhile fast, contactless NDT methods, like air-borne ultrasound, dynamic thermography and special Eddy-Current techniques are available in order to detect cracks, voids, pores and delaminations but also for characterizing fiber content, distribution and alignment. In Metal-Matrix Composites US back-scattering can be used for this purpose. US run-time measurements allow the detection of thermal stresses at the metal-matrix interface. Another important area is the necessity for NDT in joining. To achieve an optimum material utilization and product safety as well as the best possible production efficiency, there is a need for NDT methods for in-line inspection of the joint quality while joining or immediately afterwards. For this purpose EMAT (Electromagnetic Acoustic Transducer) technique or Acoustic Emission testing can be used.

  7. Antidepressant-like effect of different estrogenic compounds in the forced swimming test. (United States)

    Estrada-Camarena, Erika; Fernández-Guasti, Alonso; López-Rubalcava, Carolina


    The present study evaluated the possible antidepressant-like action of the natural estrogen 17beta-estradiol (E(2), 2.5-10 microg/rat), the synthetic steroidal estrogen ethinyl-estradiol (EE(2), 1.25-10.0 microg/rat), and the nonsteroidal synthetic estrogen, diethyl-stilbestrol (DES, 0.25-1.0 mg/rat) in ovariectomized adult female Wistar rats using the forced swimming test (FST). The behavioral profile induced by the estrogens was compared with that induced by the antidepressants fluoxetine (FLX, 2.5-10 mg/kg) and desipramine (DMI, 2.5-10 mg/kg). In addition, the temporal course of the antidepressant-like action of the estrogenic compounds was analyzed. FLX and DMI induced an antidepressant-like effect characterized by a reduced immobility and increased swimming for FLX and decreased immobility and increased climbing for DMI. Both E(2) and EE(2) produced a decrease in immobility and an increase in swimming, suggesting an antidepressant-like action. DES did not affect the responses in this animal model of depression at any dose tested. The time course analysis of the actions of E(2) (10 microg/rat) and EE(2) (5 microg/rat) showed that both compounds induced an antidepressant-like effect observed 1 h after their injection lasting for 2-3 days.

  8. Design and Testing of a Shell-Encapsulated Solar Collector with the Compound Surface Concentrators

    Directory of Open Access Journals (Sweden)

    Hongfei Zheng


    Full Text Available This paper presents design and testing of a shell-encapsulated solar collector which can be used in north area of China for wall-amounting installation. The designed solar collector is based on the combination of a novel compound curved surface concentrator and an aluminum concentric solar receiver, which is contained in a glass evacuated-tube. As there is no perforative joint between the double-skin glass evacuated-tube and the aluminum concentric solar receiver, the difficulty of vacuum keeping for a glass-metal joint is avoided. The cavity shell provides an additional thermal insulation to reduce heat loss of the designed solar collector. The working principle of the compound curved surface concentrator is described. The ray-tracing results are given to show the effect of deviation angle of the concentrator on its optical efficiency, hence determining its maximum acceptance angle. A prototype of the designed solar collector has been constructed and tested under the sunny winter weather condition. The experimental results indicate that the hot water temperature higher than 80°C with a daily average efficiency of about 45~50% has been achieved at the average ambient temperature below 0°C, so the designed solar collector can produce hot water at a useful temperature in winter.

  9. Novel non-platinum metal catalyst material

    DEFF Research Database (Denmark)


    The present invention relates to a novel non-platinum metal catalyst material for use in low temperature fuel cells and electrolysers and to fuel cells and electrolysers comprising the novel non-platinum metal catalyst material. The present invention also relates to a novel method for synthesizing...... the novel non-platinum metal catalyst material....

  10. Coating Carbon Fibers With Platinum (United States)

    Effinger, Michael R.; Duncan, Peter; Coupland, Duncan; Rigali, Mark J.


    A process for coating carbon fibers with platinum has been developed. The process may also be adaptable to coating carbon fibers with other noble and refractory metals, including rhenium and iridium. The coated carbon fibers would be used as ingredients of matrix/fiber composite materials that would resist oxidation at high temperatures. The metal coats would contribute to oxidation resistance by keeping atmospheric oxygen away from fibers when cracks form in the matrices. Other processes that have been used to coat carbon fibers with metals have significant disadvantages: Metal-vapor deposition processes yield coats that are nonuniform along both the lengths and the circumferences of the fibers. The electrical resistivities of carbon fibers are too high to be compatible with electrolytic processes. Metal/organic vapor deposition entails the use of expensive starting materials, it may be necessary to use a furnace, and the starting materials and/or materials generated in the process may be hazardous. The present process does not have these disadvantages. It yields uniform, nonporous coats and is relatively inexpensive. The process can be summarized as one of pretreatment followed by electroless deposition. The process consists of the following steps: The surfaces of the fiber are activated by deposition of palladium crystallites from a solution. The surface-activated fibers are immersed in a solution that contains platinum. A reducing agent is used to supply electrons to effect a chemical reduction in situ. The chemical reduction displaces the platinum from the solution. The displaced platinum becomes deposited on the fibers. Each platinum atom that has been deposited acts as a catalytic site for the deposition of another platinum atom. Hence, the deposition process can also be characterized as autocatalytic. The thickness of the deposited metal can be tailored via the duration of immersion and the chemical activity of the solution.

  11. EGFR-targeting peptide-coupled platinum(IV) complexes. (United States)

    Mayr, Josef; Hager, Sonja; Koblmüller, Bettina; Klose, Matthias H M; Holste, Katharina; Fischer, Britta; Pelivan, Karla; Berger, Walter; Heffeter, Petra; Kowol, Christian R; Keppler, Bernhard K


    The high mortality rate of lung cancer patients and the frequent occurrence of side effects during cancer therapy demonstrate the need for more selective and targeted drugs. An important and well-established target for lung cancer treatment is the occasionally mutated epidermal growth factor receptor (EGFR). As platinum(II) drugs are still the most important therapeutics against lung cancer, we synthesized in this study the first platinum(IV) complexes coupled to the EGFR-targeting peptide LARLLT (and the shuffled RTALLL as reference). Notably, HPLC-MS measurements revealed two different peaks with the same molecular mass, which turned out to be a transcyclization reaction in the linker between maleimide and the coupled cysteine moiety. With regard to the EGFR specificity, subsequent biological investigations (3-day viability, 14-day clonogenic assays and platinum uptake) on four different cell lines with different verified EGFR expression levels were performed. Unexpectedly, the results showed neither an enhanced activity nor an EGFR expression-dependent uptake of our new compounds. Consequently, fluorophore-coupled peptides were synthesized to re-evaluate the targeting ability of LARLLT itself. However, also with these molecules, flow cytometry measurements showed no correlation of drug uptake with the EGFR expression levels. Taken together, we successfully synthesized the first platinum(IV) complexes coupled to an EGFR-targeting peptide; however, the biological investigations revealed that LARLLT is not an appropriate peptide for enhancing the specific uptake of small-molecule drugs into EGFR-overexpressing cancer cells.

  12. Platinum Group Metals New Material

    Institute of Scientific and Technical Information of China (English)

    XIE Ming; ZHANG Jiankang; WANG Saibei; HU Jieqiong; LIU Manmen; CHEN Yongtai; ZHANG Jiming; YANG Youcai; YANG Yunfeng; ZHANG Guoquan


    Platinum group metals (PGM) include six elements,namely Pt,Pd,Rh,Ir,Os and Ru.PGM and their alloys are the important fundamental materials for modern industry and national defense construction,they have special physical and chemical properties,widely used in metallurgy,chemical,electric,electronic,information,energy,environmental protection,aviation,aerospace,navigation and other high technology industry.Platinum group metals and their alloys,which have good plasticity and processability,can be processed to electrical contact materials,resistance materials,solder,electronic paste,temperature-measurement materials,elastic materials,magnetic materials and high temperature structural materials.

  13. Thermodynamic ground states of platinum metal nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Aberg, D; Sadigh, B; Crowhurst, J; Goncharov, A


    We have systematically studied the thermodynamic stabilities of various phases of the nitrides of the platinum metal elements using density functional theory. We show that for the nitrides of Rh, Pd, Ir and Pt two new crystal structures, in which the metal ions occupy simple tetragonal lattice sites, have lower formation enthalpies at ambient conditions than any previously proposed structures. The region of stability can extend up to 17 GPa for PtN{sub 2}. Furthermore, we show that according to calculations using the local density approximation, these new compounds are also thermodynamically stable at ambient pressure and thus may be the ground state phases for these materials. We further discuss the fact that the local density and generalized gradient approximations predict different values of the absolute formation enthalpies as well different relative stabilities between simple tetragonal and the pyrite or marcasite structures.

  14. Investigation of mechanical and structural characteristics of platinum and palladium at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Trumie, B. T.; Gomidzelovie, L.; Marjanovic, S. R.; Krstic, V. R.


    In order to broaden future application of products based on platinum and palladium a comparative analysis of their high-temperature mechanical properties was performed. Platinum and palladium are of great importance and are widely used in chemical industry, electronics, for making laboratory dishes, to name a few. Mechanical properties of pure metals, such as: tensile strength, creep rate and rupture time were investigated using universal testing machine for tensile testing of materials. Microstructure of samples was investigated by optical microscopy. Based on obtained results it can be concluded that the platinum, compared to palladium, is superior for high-temperature applications. (Author)

  15. Bis- and Tetrakis(carboxylato)platinum(IV) complexes with mixed axial ligands - synthesis, characterization, and cytotoxicity. (United States)

    Hoffmeister, Björn R; Hejl, Michaela; Adib-Razavi, Mahsa S; Jakupec, Michael A; Galanski, Markus; Keppler, Bernhard K


    A series of twelve novel diamminetetrakis(carboxylato)platinum(IV) and 18 novel bis(carboxylato)dichlorido(ethane-1,2-diamine)platinum(IV) complexes with mixed axial carboxylato ligands was synthesized and characterized by multinuclear (1) H-, (13) C-, (15) N-, and (195) Pt-NMR spectroscopy. Their cytotoxic potential was evaluated (by MTT assay) against three human cancer cell lines derived from ovarian teratocarcinoma (CH1/PA-1), lung (A549), and colon carcinoma (SW480). In the cisplatin-sensitive CH1/PA-1 cancer cell line, diamminetetrakis(carboxylato)platinum(IV) complexes showed IC50 values in the low micromolar range, whereas, for the most lipophilic compounds of the bis(carboxylato)dichlorido(ethane-1,2-diamine)platinum(IV) series, IC50 values in the nanomolar range were found. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.

  16. [Formylation of porphyrin platinum complexes]. (United States)

    Rumiantseva, V D; Konovalenko, L I; Nagaeva, E A; Mironov, A F


    The formylation reaction of platinum complexes of beta-unsubstituted porphyrins was studied. The interaction of deuteroporphyrin IX derivatives with the Vilsmeyer reagent led to the selective formylation of their macrocycles in the beta position. The resulting formyl derivatives of the porphyrins are of interest for fluorescent immunoassay.

  17. The Versatile Behavior of Platinum Alkyne Complexes towards XeF2 : Formation of Fluorovinyl and Fluorido Complexes. (United States)

    Berger, Josefine; Braun, Thomas; Ahrens, Theresia; Kläring, Paul; Laubenstein, Reik; Braun-Cula, Beatrice


    Reactions of platinum(0) tolane complexes, bearing a chelating ligand with P and N donor atoms, with the electrophilic fluorinating agent XeF2 give facile access to platinum(II) β-fluorovinyl fluorido complexes. A series of new platinum(II) β-fluorovinyl complexes have been synthesized and were structurally characterized. Further oxidation with XeF2 led to ortho-metalated platinum(IV) fluorido compounds. Additional reactions of platinum(0) tolane complexes, bearing a chelating P,P donor ligand, with XeF2 led to a variety of fluorido and fluorovinyl complexes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Preliminary study fo the interference of proteic compounds of radiopharmaceuticals in the test of lisadode amebocitos de limulus (LAL)

    CERN Document Server

    Aldana, C


    In this thesis the objective was evaluate the interference of proteic compounds of the radiopharmaceuticals in the test LAL (lisado of amebocitos de limulus) for this, macroagregates of albumina (MAA) was used with metilendifosfonato (MDP) as control that is the radiopharmaceutical more used in the nuclear medicine centers of the country. Initially preliminary test were carried out to assess if some of two radiopharmaceuticals would cause interference with LAL test, after the test was validated and finally routine tests were made. With the preliminary assays was concluded that proteic compounds did not cause interference (albumina with a concentration of 2 md/dl) with the MAA. However with the MDP cause interference with LAL test. The interference was eliminated with a dilution of 1:8 of the sample. Was concluded that the success of LAL test depends on conditions such as temperature, pH, constant incubation (no minimum variations) and that is a good test for quality control of the radiopharmaceuticals.


    Institute of Scientific and Technical Information of China (English)

    CHEN Yuanyin; MENG Lingzhi; YIN Yihua; GENG Chengai


    The title polymer was prepared from 5-diethylamino-3-thia-pentyl glycidyl ether and diethylene glycol bisglycidyl ether via ring-opening copolymerization. It was found that this reaction could be catalyzed by sodium, but not Lewis acid. The obtained polymer can coordinate with platinum compound, and the platinum complex is a new kind of catalyst for the hydrosilylation of olefins with triethoxysilane.

  20. Potencies of estrogenic compounds in in vitro screening assays and in life cycle tests with zebrafish in vivo. (United States)

    Segner, H; Navas, J M; Schäfers, C; Wenzel, A


    The objective of this study was to compare the estrogenic potency of environmental estrogens at two testing tiers: at the initial level of in vitro screening assays, and at the level of definitive fish reproduction tests in vivo. The in vitro tests included a recombinant yeast estrogen receptor (ER) assay, a competitive radioreceptor assay using the hepatic ER of carp (Cyprinus carpio), and assays on vitellogenin induction in cultured hepatocytes of rainbow trout (Oncorhynchus mykiss) and carp. In vivo, full life cycle tests with zebrafish (Danio rerio) were performed, using fertilization success as estrogen-sensitive reproductive endpoint. The test compounds included the natural estrogen 17beta-estradiol (E2) (only applied in the in vitro assays); the synthetic estrogen ethynylestradiol (EE2); and two xenoestrogens, 4-tert-octylphenol (OP) and bisphenol A (BPA). Among the in vitro assays, differences were observed in the relative ranking of the test substances, and in the absolute sensitivity (EC50 values), although the interassay differences of EC50 values were within one order of magnitude. The in vivo activity of the test compounds was not accurately predicted by the in vitro assays, with respect to neither sensitivity nor ranking. The in vitro assays tended to overestimate the relative potency of the xenoestrogens; i.e. the ratio between the activity of the reference compound, EE2, and that of the test compound. The best prediction of the in vivo fish test results was obtained from the recombinant yeast assay.

  1. Low-molecular compounds of erythrocytes

    Directory of Open Access Journals (Sweden)

    O. O. Sorochan


    Full Text Available Glucose and free amino acids levels in rats’ blood plasma and erythrocytes hemolysate under carcinoma Geuren Т8 development as well as after introduction of Rhenium (III and сys-Platinum compounds were studied. The complex Rhenium (III compounds with organic ligands act as antioxidant and normalize the concentration of low-molecular compounds in erythrocytes under the carcinogenesis.

  2. Flatworm models in pharmacological research: the importance of compound stability testing. (United States)

    Stalmans, Sofie; Willems, Maxime; Adriaens, Els; Remon, Jean-Paul; D'Hondt, Matthias; De Spiegeleer, Bart


    Flatworms possess adult pluripotent stem cells, which make them extraordinary experimental model organisms to assess in vivo the undesirable effects of substances on stem cells. Currently, quality practices, implying evaluation of the stability of the test compound under the proposed experimental conditions, are uncommon in this research field. Nevertheless, performing a stability study during the rational design of in vivo assay protocols will result in more reliable assay results. To illustrate the influence of the stability of the test substance on the final experimental outcome, we performed a short-term International Conference on Harmonization (ICH)-based stability study of cyclophosphamide in the culture medium, to which a marine flatworm model Macrostomum lignano is exposed. Using a validated U(H)PLC method, it was demonstrated that the cyclophosphamide concentration in the culture medium at 20°C is lowered to 80% of the initial concentration after 21days. The multiwell plates, flatworms and diatoms, as well as light exposure, did not influence significantly the cyclophosphamide concentration in the medium. The results of the stability study have practical implications on the experimental set-up of the carcinogenicity assay like the frequency of medium renewal. This case study demonstrates the benefits of applying appropriate quality guidelines already during fundamental research increasing the credibility of the results.

  3. Interactions of skin thickness and physicochemical properties of test compounds in percutaneous penetration studies

    DEFF Research Database (Denmark)

    Wilkinson, Simon C.; Maas, Wilfred J. M.; Nielsen, Jesper Bo


    conditions was measured using flow through cells for 8-24 h. Saline (adjusted to pH 7.4) was used as receptor fluid, with BSA added for studies with testosterone and propoxur. Following exposure, the remaining surface dose was removed by swabbing and the skin digested prior to scintillation counting. Results......Abstract   Objectives: To determine the effect of skin thickness on the percutaneous penetration and distribution of test compounds with varying physicochemical properties using in vitro systems. Studies were carried out in accordance with OECD guidelines on skin absorption tests. Methods......: Percutaneous penetration of caffeine (log P -0.01), testosterone (log P 3.32), propoxur (log P 1.52) (finite dose in ethanol to water vehicle ratio) and butoxyethanol (log P 0.83) (undiluted finite dose or as an infinite dose 50% [v/v] aqueous solution) through skin of varying thicknesses under occluded...

  4. Interactions of skin thickness and physicochemical properties of test compounds in percutaneous penetration studies

    DEFF Research Database (Denmark)

    Wilkinson, Simon C.; Maas, Wilfred J. M.; Nielsen, Jesper Bo


    Abstract   Objectives: To determine the effect of skin thickness on the percutaneous penetration and distribution of test compounds with varying physicochemical properties using in vitro systems. Studies were carried out in accordance with OECD guidelines on skin absorption tests. Methods......: Percutaneous penetration of caffeine (log P -0.01), testosterone (log P 3.32), propoxur (log P 1.52) (finite dose in ethanol to water vehicle ratio) and butoxyethanol (log P 0.83) (undiluted finite dose or as an infinite dose 50% [v/v] aqueous solution) through skin of varying thicknesses under occluded...... conditions was measured using flow through cells for 8-24 h. Saline (adjusted to pH 7.4) was used as receptor fluid, with BSA added for studies with testosterone and propoxur. Following exposure, the remaining surface dose was removed by swabbing and the skin digested prior to scintillation counting. Results...

  5. Synthesis of platinum and palladium complexes with bis-(hydroxy imines

    Directory of Open Access Journals (Sweden)

    Lucas M. Arantes


    Full Text Available The Schiff bases are an important class of compounds well used as ligands in coordination chemistry. The functionalized bis-imines, that represent a specific group of Schiff base, have been studied in our research group both for the evaluation of biological activity, against fungi and cancer, as for organocatalyst. Here the bis-imines 1 and 4 were synthesized in good yields by condensation of hydroxylated benzaldehydes with phenylenediamines. After that they were matched with Platinum and palladium salts providing three metallic complex (2, 3 and 5 that were fully characterized by nuclear magnetic resonance and mass spectrometry with electrospray ionization. Now these complexes are being tested in cross-coupling reactions of Heck and Suzuki.

  6. Film Platinum Thermal Resistance PT1000 Application in Thermal Test%薄膜铂热电阻PT1000在热测试中的应用

    Institute of Scientific and Technical Information of China (English)

    陆心宇; 郭庆


    The thermal test of electronic equipment is complete thermal analysis and thermal design in electronic equipment and complete the prototype, the prototype of electronic equipment in the actual test, to verify the effect of the thermal design and thermal analysis. Eight-way real-time temperature measuring device PT1000 is adopted as a temperature sensor. To meet the needs of the hot test, the article gives the eight-way temperature measuring device design process.%电子设备的热测试是在电子设备完成热分析、热设计和完成样机之后,对电子设备样机的实际测试,以检测验证热设计与热分析的正确性。八路温度实时测量装置采用了薄膜铂热电阻PT1000作为温度传感器,以满足热测试的需求,文章给出了八路实时温度测量装置设计和工作原理。

  7. A comparative study of pharmacokinetics, urinary excretion and tissue distribution of platinum in rats following a single-dose oral administration of two platinum(IV) complexes LA-12 (OC-6-43)-bis(acetato)(1-adamantylamine)amminedichloroplatinum(IV) and satraplatin (OC-6-43)-bis(acetato)amminedichloro(cyclohexylamine)platinum(IV). (United States)

    Sova, Petr; Mistr, Adolf; Kroutil, Ales; Semerád, Martin; Chlubnová, Hana; Hrusková, Veronika; Chládková, Jirina; Chládek, Jaroslav


    This study compared the pharmacokinetics, tissue distribution, and urinary excretion of platinum in rats after single oral doses of LA-12 and satraplatin. Both platinum derivatives were administered to male Wistar rats as suspensions in methylcellulose at four equimolar doses within the range of 37.5-300 mg LA-12/kg body weight. Blood sampling was performed until 72 h, and plasma and plasma ultrafiltrate were separated. Moreover, urine was collected until 72 h, and kidney and liver tissue samples were obtained at several times after administration. Platinum was measured by atomic absorption spectrometry. The pharmacokinetics of platinum was analyzed by population modelling and post hoc Bayesian estimation as well as using non-compartmental pharmacokinetic analysis of the mean concentration-time curves. Platinum was detected in all plasma and ultrafiltrate samples 15 min after oral administration of both compounds and peaked between 3-4 h and 1-3 h, respectively. Similar for LA-12 and satraplatin, the C (max) and AUC values of plasma and ultrafiltrate platinum increased less than in proportion to dose. The mean C (max) and AUC values of plasma platinum observed after administration of LA-12 were from 0.84 to 2.5 mg/l and from 20.2 to 75.9 mg h/l. For ultrafiltrate platinum, the corresponding ranges were 0.16-0.78 mg/l and 0.63-1.8 mg h/l, respectively. The AUC of plasma platinum was higher after satraplatin (P platinum after the doses of 150 mg and 300 mg/kg (P platinum dose was below 5% for both compounds, and it decreased with the dose of satraplatin (P platinum was similar regardless of the dose and compound administered. Platinum concentrations in the liver homogenate exceeded those in the kidney. Distribution of platinum to tissues was higher after LA-12 compared to satraplatin. The difference in kidney platinum increased with dose and was twofold after 350 mg/kg LA-12. Liver platinum was twofold higher after LA-12 across all four doses. In conclusion, this

  8. Finely Tuned Asymmetric Platinum(IV) Anticancer Complexes: Structure-Activity Relationship and Application as Orally Available Prodrugs. (United States)

    Yap, Siew Qi; Chin, Chee Fei; Hong Thng, Agnes Hwee; Pang, Yi Yun; Ho, Han Kiat; Ang, Wee Han


    Platinum(IV) bis-carboxylates are highly versatile prodrug scaffolds with different axial ligands that can be functionalized while keeping the platinum(II) pharmacophore intact. Using a sequential acylation strategy, we developed a class of Pt(IV) prodrugs of cisplatin with contrasting lipophilic and hydrophilic ligands. We investigated their stability, reduction rates, lipophilicity, aqueous solubility, and antiproliferative efficacies, and assessed for correlations among the parameters that could be useful in drug design. We showed that compounds with high lipophilicity result in better antiproliferative effects in vitro and in vivo, with one of the three compounds tested showing better efficacy than satraplatin against an animal model of colorectal cancer, owing to its higher solubility and lower reduction rates. Our asymmetric Pt(IV) prodrugs may pave the way for a highly predictable, fine-tuned class of orally available Pt(IV) prodrugs for the treatment of colorectal cancer. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Production of Platinum Atom Nanoclusters at One End of Helical Plant Viruses

    Directory of Open Access Journals (Sweden)

    Yuri Drygin


    Full Text Available Platinum atom clusters (Pt nanoparticles, Pt-NPs were produced selectively at one end of helical plant viruses, tobacco mosaic virus (TMV and potato virus X (PVX, when platinum coordinate compounds were reduced chemically by borohydrides. Size of the platinum NPs depends on conditions of the electroless deposition of platinum atoms on the virus. Results suggest that the Pt-NPs are bound concurrently to the terminal protein subunits and the 5′ end of encapsidated TMV RNA. Thus, a special structure of tobacco mosaic virus and potato X virus particles with nanoparticles of platinum, which looks like a push-pin with platinum head and virus needle, was obtained. Similar results were obtained with ultrasonically fragmented TMV particles. By contrast, the Pt-NPs fully filled the central axial hole of in vitro assembled RNA-free TMV-like particles. We believe that the results presented here will be valuable in the fundamental understanding of interaction of viral platforms with ionic metals and in a mechanism of nanoparticles formation.

  10. Surface characterization of platinum electrodes. (United States)

    Solla-Gullón, José; Rodríguez, Paramaconi; Herrero, Enrique; Aldaz, Antonio; Feliu, Juan M


    The quantitative analysis of the different surface sites on platinum samples is attempted from pure voltammetric data. This analysis requires independent knowledge of the fraction of two-dimensional (111) and (100) domains. Specific site-probe reactions are employed to achieve this goal. Irreversibly-adsorbed bismuth and tellurium have been revealed to be sensitive to the presence of (111) terrace domains of different width whereas almost all sites involved in (100) ordered domains have been characterized through germanium adatoms. The experimental protocol follows that used with well-defined single-crystal electrodes and, therefore, requires careful control of the surface cleanliness. Platinum basal planes and their vicinal stepped surfaces have been employed to obtain calibration plots between the charge density measured under the adatom redox peak, specific for the type of surface site, and the corresponding terrace size. The evaluation of the (100) bidimensional domains can also be achieved using the voltammetric profiles, once the fraction of (111) ordered domains present in the polyoriented platinum has been determined and their featureless contribution has been subtracted from the whole voltammetric response. Using that curve, it is possible to perform a deconvolution of the adsorption states of the polycrystalline sample different from those related to (111) domains. The fraction of (100)-related states in the deconvoluted voltammogram can then be compared to that expected from the independent estimation coming from the charge involved in the redox process undergone by the irreversibly-adsorbed germanium and thus check the result of the deconvolution. The information about the surface-site distribution can also be applied to analyze the voltammetric profile of nanocrystalline platinum electrodes.

  11. Detection of volatile organic compounds released by wood furniture based on a cataluminescence test system. (United States)

    Miao, Yanfeng; Deng, Fangming; Chen, Yulong; Guan, Huiyuan


    Wood furniture is an important source of indoor air pollution. To date, the detection of harmful substances in wood furniture has relied on the control of a single formaldehyde component, therefore the detection and evaluation of pollutants released by wood furniture are necessary. A novel method based on a cataluminescence (CTL) sensor system generated on the surface of nano-3TiO2-2BiVO4 was proposed for the simultaneous detection of pollutants released by wood furniture. Formaldehyde and benzene were selected as a model to investigate the CTL-sensing properties of the sensor system. Field emission scanning electronic microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) were employed to characterize the as-prepared samples. The results showed that the as-prepared test system exhibited outstanding CTL properties such as stable intensity, a high signal-to-noise ratio, and short response and recovery times. In addition, the limit of detection for formaldehyde and benzene was below the standard permitted concentrations. Moreover, the sensor system showed outstanding selectivity for formaldehyde and benzene compared with eight other common volatile organic compounds (VOCs). The performance of the sensor system will enable furniture VOC limit emissions standards to be promulgated as soon as possible.

  12. An ERK-dependent pathway to Noxa expression regulates apoptosis by platinum-based chemotherapeutic drugs. (United States)

    Sheridan, C; Brumatti, G; Elgendy, M; Brunet, M; Martin, S J


    Cisplatin is a widely used cancer chemotherapeutic that promotes DNA damage-associated apoptosis. Although platinum compounds are known to form DNA adducts and provoke DNA damage, the molecular mechanism of cisplatin-induced cell death remains unclear. In this article, we show that the BH3-only protein Noxa is strongly transcriptionally upregulated in response to cisplatin and related platinum compounds. Cisplatin-induced Noxa expression was ERK dependent, but p53 independent, and inhibition of ERK activation markedly attenuated cisplatin-induced cell death, as well as Noxa expression. Furthermore, siRNA-mediated ablation of Noxa expression also inhibited cisplatin-induced cell death and permitted clonogenic survival. These observations reveal a novel ERK-regulated route to Noxa expression that is important for the cell killing activity of platinum-based chemotherapeutic drugs.

  13. The Effects of Molecular Properties on Ready Biodegradation of Aromatic Compounds in the OECD 301B CO2 Evolution Test. (United States)

    He, Mei; Mei, Cheng-Fang; Sun, Guo-Ping; Li, Hai-Bei; Liu, Lei; Xu, Mei-Ying


    Ready biodegradation is the primary biodegradability of a compound, which is used for discriminating whether a compound could be rapidly and readily biodegraded in the natural ecosystems in a short period and has been applied extensively in the environmental risk assessment of many chemicals. In this study, the effects of 24 molecular properties (including 2 physicochemical parameters, 10 geometrical parameters, 6 topological parameters, and 6 electronic parameters) on the ready biodegradation of 24 kinds of synthetic aromatic compounds were investigated using the OECD 301B CO2 Evolution test. The relationship between molecular properties and ready biodegradation of these aromatic compounds varied with molecular properties. A significant inverse correlation was found for the topological parameter TD, five geometrical parameters (Rad, CAA, CMA, CSEV, and N c), and the physicochemical parameter K ow, and a positive correlation for two topological parameters TC and TVC, whereas no significant correlation was observed for any of the electronic parameters. Based on the correlations between molecular properties and ready biodegradation of these aromatic compounds, the importance of molecular properties was demonstrated as follows: geometrical properties > topological properties > physicochemical properties > electronic properties. Our study first demonstrated the effects of molecular properties on ready biodegradation by a number of experiment data under the same experimental conditions, which should be taken into account to better guide the ready biodegradation tests and understand the mechanisms of the ready biodegradation of aromatic compounds.

  14. Phosphoric acid fuel cell platinum use study (United States)

    Lundblad, H. L.


    The U.S. Department of Energy is promoting the private development of phosphoric acid fuel cell (PAFC) power plants for terrestrial applications. Current PAFC technology utilizes platinum as catalysts in the power electrodes. The possible repercussions that the platinum demand of PAFC power plant commercialization will have on the worldwide supply and price of platinum from the outset of commercialization to the year 2000 are investigated. The platinum demand of PAFC commercialization is estimated by developing forecasts of platinum use per unit of generating capacity and penetration of PAFC power plants into the electric generation market. The ability of the platinum supply market to meet future demands is gauged by assessing the size of platinum reserves and the capability of platinum producers to extract, refine and market sufficient quantities of these reserves. The size and timing of platinum price shifts induced by the added demand of PAFC commercialization are investigated by several analytical methods. Estimates of these price shifts are then used to calculate the subsequent effects on PAFC power plant capital costs.

  15. Pilot scale test of a produced water-treatment system for initial removal of organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, Enid J [Los Alamos National Laboratory; Kwon, Soondong [UT-AUSTIN; Katz, Lynn [UT-AUSTIN; Kinney, Kerry [UT-AUSTIN


    A pilot-scale test to remove polar and non-polar organics from produced water was performed at a disposal facility in Farmington NM. We used surfactant-modified zeolite (SMZ) adsorbent beds and a membrane bioreactor (MBR) in combination to reduce the organic carbon content of produced water prior to reverse osmosis (RO). Reduction of total influent organic carbon (TOC) to 5 mg/L or less is desirable for efficient RO system operation. Most water disposed at the facility is from coal-bed gas production, with oil production waters intermixed. Up to 20 gal/d of produced water was cycled through two SMZ adsorbent units to remove volatile organic compounds (BTEX, acetone) and semivolatile organic compounds (e.g., napthalene). Output water from the SMZ units was sent to the MBR for removal of the organic acid component of TOC. Removal of inorganic (Mn and Fe oxide) particulates by the SMZ system was observed. The SMZ columns removed up to 40% of the influent TOC (600 mg/L). BTEX concentrations were reduced from the initial input of 70 mg/L to 5 mg/L by the SMZ and to an average of 2 mg/L after the MBR. Removal rates of acetate (input 120-170 mg/L) and TOC (input up to 45 mg/L) were up to 100% and 92%, respectively. The water pH rose from 8.5 to 8.8 following organic acid removal in the MBR; this relatively high pH was likely responsible for observed scaling of the MBR internal membrane. Additional laboratory studies showed the scaling can be reduced by metered addition of acid to reduce the pH. Significantly, organic removal in the MBR was accomplished with a very low biomass concentration of 1 g/L throughout the field trial. An earlier engineering evaluation shows produced water treatment by the SMZ/MBR/RO system would cost from $0.13 to $0.20 per bbl at up to 40 gpm. Current estimated disposal costs for produced water are $1.75 to $4.91 per bbl when transportation costs are included, with even higher rates in some regions. Our results suggest that treatment by an SMZ

  16. On Revising Noun Compounds: Four Tests. CDC Technical Report No. 5. (United States)

    Kaufer, David S.; Steinberg, Erwin R.

    Many influential style guides endorse the stylistic prescription that writers, particularly technical writers, should revise noun compounds into phrasal or clausal paraphrases. While the prescription is well-intentioned, it fails to take into account that a reader's comprehension of compounds, whether long or short, is a complex process dependent…

  17. WC as a non-platinum hydrogen evolution electrocatalyst for high temperature PEM water electrolysers

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Petrushina, Irina; Christensen, Erik


    Tungsten carbide (WC) nanopowder was tested as a non-platinum cathode electrocatalyst for polymer electrolyte membrane (PEM) water electrolysers, operating at elevated temperatures. It was prepared in thermal plasma reactor with confined plasma jet from WO3 precursor in combination with CH4...... carburizing agent. The results of the investigation showed that the activity of tungsten carbide as cathode electrocatalyst increases significantly with temperature and this effect is more pronounced than for platinum, especially, at 150 °C....

  18. Synthesis, DFT calculations and cytotoxic investigation of platinum complexes with 3-thiolanespiro-5‧-hydantoin and 4-thio-1H-tetrahydropyranespiro-5‧-hydantoin (United States)

    Bakalova, Adriana; Buyukliev, Rossen; Momekov, Georgi


    Two organic compounds - 3-thiolanespiro-5‧-hydantoin, 4-thio-1H-tetrahydropyranespiro-5‧-hydantoin and four new Pt(II) and Pt(IV) complexes with general formulas cis-[Pt(L)2Cl2] and cis-[Pt(L)2Cl4] were synthesized. The obtained compounds were characterized by elemental analysis, IR, 1H, 13C NMR spectroscopy. The hybrid DFT calculations were used for optimization of the structure geometries of the ligand (L1) and its Pt(II) complex (1). The calculated structural parameters such as bond lengths and angles are in good agreement with the experimental data for similar hydantoins and their platinum complexes. The obtained results showed that the geometry of the complex (1) is plane square and the bounding of the L1 with platinum ion is realized by sulfur atom from thiolane ring. The complexes were tested for cytotoxicity in vitro on four human tumor cell lines. The tested compounds exerted concentration-dependent cytotoxic effects against some of the tumor cell lines.

  19. A RASH analysis of National Toxicology Program data: Predictions for 30 compounds to be tested in rodent carcinogenesis experiments

    Energy Technology Data Exchange (ETDEWEB)

    Jones, T.D.; Easterly, C.E. [Oak Ridge National Lab., TN (United States)


    Relative potencies for 30 compounds scheduled for carcinogenic testing in the 2-year rodent bioassays were estimated based on comparisons with a wide variety of bioassay data for benzo[a]pyrene, nicotine, cisplatin, aflatoxin B1, and cyclophosphamide. Potential for oncogenic transformation of each of the compounds was estimated from short-term bioassays. Promoting strength was assigned on the basis of comparisons of the product of relative potency and test dose with the distribution of similar products obtained for 67 common compounds in the data- base of Gold et al. A potency class for promotion was assigned on the basis of whether the potency-adjusted test dosage was > 2{sigma} below the mean, > 1{sigma} below the mean, within {+-}{sigma} of the mean, >{sigma} above the mean, or > 2{sigma} above the mean, as determined from the 67 compounds. The underlying hypothesis is that a weak test dose may have a low probability of revealing a potential carcinogen, whereas a strong dose may have a high probability of producing false-positive results. Predictions are therefore directed at the central 68% of the log-normal frequency distribution according to the assumption that {+-}{sigma} represents the ideal test dose. 22 refs., 7 tabs.

  20. Compound-specific effects of diverse neurodevelopmental toxicants on global gene expression in the neural embryonic stem cell test (ESTn)

    Energy Technology Data Exchange (ETDEWEB)

    Theunissen, P.T., E-mail: [Laboratory for Health Protection Research, National Institute for Public Health and the Environment (RIVM), Bilthoven (Netherlands); Department of Toxicogenomics, Maastricht University, Maastricht (Netherlands); Robinson, J.F. [Laboratory for Health Protection Research, National Institute for Public Health and the Environment (RIVM), Bilthoven (Netherlands); Department of Toxicogenomics, Maastricht University, Maastricht (Netherlands); Netherlands Toxicogenomics Centre, Maastricht (Netherlands); Pennings, J.L.A. [Laboratory for Health Protection Research, National Institute for Public Health and the Environment (RIVM), Bilthoven (Netherlands); Netherlands Toxicogenomics Centre, Maastricht (Netherlands); Herwijnen, M.H. van [Department of Toxicogenomics, Maastricht University, Maastricht (Netherlands); Kleinjans, J.C.S. [Department of Toxicogenomics, Maastricht University, Maastricht (Netherlands); Netherlands Toxicogenomics Centre, Maastricht (Netherlands); Piersma, A.H. [Laboratory for Health Protection Research, National Institute for Public Health and the Environment (RIVM), Bilthoven (Netherlands); Netherlands Toxicogenomics Centre, Maastricht (Netherlands); Institute for Risk Assessment Sciences, Faculty of Veterinary Sciences, Utrecht University, Utrecht (Netherlands)


    Alternative assays for developmental toxicity testing are needed to reduce animal use in regulatory toxicology. The in vitro murine neural embryonic stem cell test (ESTn) was designed as an alternative for neurodevelopmental toxicity testing. The integration of toxicogenomic-based approaches may further increase predictivity as well as provide insight into underlying mechanisms of developmental toxicity. In the present study, we investigated concentration-dependent effects of six mechanistically diverse compounds, acetaldehyde (ACE), carbamazepine (CBZ), flusilazole (FLU), monoethylhexyl phthalate (MEHP), penicillin G (PENG) and phenytoin (PHE), on the transcriptome and neural differentiation in the ESTn. All compounds with the exception of PENG altered ESTn morphology (cytotoxicity and neural differentiation) in a concentration-dependent manner. Compound induced gene expression changes and corresponding enriched gene ontology biological processes (GO–BP) were identified after 24 h exposure at equipotent differentiation-inhibiting concentrations of the compounds. Both compound-specific and common gene expression changes were observed between subsets of tested compounds, in terms of significance, magnitude of regulation and functionality. For example, ACE, CBZ and FLU induced robust changes in number of significantly altered genes (≥ 687 genes) as well as a variety of GO–BP, as compared to MEHP, PHE and PENG (≤ 55 genes with no significant changes in GO–BP observed). Genes associated with developmentally related processes (embryonic morphogenesis, neuron differentiation, and Wnt signaling) showed diverse regulation after exposure to ACE, CBZ and FLU. In addition, gene expression and GO–BP enrichment showed concentration dependence, allowing discrimination of non-toxic versus toxic concentrations on the basis of transcriptomics. This information may be used to define adaptive versus toxic responses at the transcriptome level.

  1. Compound-specific effects of diverse neurodevelopmental toxicants on global gene expression in the neural embryonic stem cell test (ESTn). (United States)

    Theunissen, P T; Robinson, J F; Pennings, J L A; van Herwijnen, M H; Kleinjans, J C S; Piersma, A H


    Alternative assays for developmental toxicity testing are needed to reduce animal use in regulatory toxicology. The in vitro murine neural embryonic stem cell test (ESTn) was designed as an alternative for neurodevelopmental toxicity testing. The integration of toxicogenomic-based approaches may further increase predictivity as well as provide insight into underlying mechanisms of developmental toxicity. In the present study, we investigated concentration-dependent effects of six mechanistically diverse compounds, acetaldehyde (ACE), carbamazepine (CBZ), flusilazole (FLU), monoethylhexyl phthalate (MEHP), penicillin G (PENG) and phenytoin (PHE), on the transcriptome and neural differentiation in the ESTn. All compounds with the exception of PENG altered ESTn morphology (cytotoxicity and neural differentiation) in a concentration-dependent manner. Compound induced gene expression changes and corresponding enriched gene ontology biological processes (GO-BP) were identified after 24h exposure at equipotent differentiation-inhibiting concentrations of the compounds. Both compound-specific and common gene expression changes were observed between subsets of tested compounds, in terms of significance, magnitude of regulation and functionality. For example, ACE, CBZ and FLU induced robust changes in number of significantly altered genes (≥ 687 genes) as well as a variety of GO-BP, as compared to MEHP, PHE and PENG (≤ 55 genes with no significant changes in GO-BP observed). Genes associated with developmentally related processes (embryonic morphogenesis, neuron differentiation, and Wnt signaling) showed diverse regulation after exposure to ACE, CBZ and FLU. In addition, gene expression and GO-BP enrichment showed concentration dependence, allowing discrimination of non-toxic versus toxic concentrations on the basis of transcriptomics. This information may be used to define adaptive versus toxic responses at the transcriptome level.

  2. Platinum-induced structural collapse in layered oxide polycrystalline films

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jianlin; Liu, Changhui [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Huang, Haoliang [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026 (China); Fu, Zhengping; Peng, Ranran, E-mail:, E-mail: [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026 (China); Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026 (China); Zhai, Xiaofang [Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026 (China); Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026 (China); Lu, Yalin, E-mail:, E-mail: [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026 (China); Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026 (China); Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230026 (China); Laser and Optics Research Center, Department of Physics, United States Air Force Academy, Colorado 80840 (United States)


    Effect of a platinum bottom electrode on the SrBi{sub 5}Fe{sub 1−x}Co{sub x}Ti{sub 4}O{sub 18} layered oxide polycrystalline films was systematically studied. The doped cobalt ions react with the platinum to form a secondary phase of PtCoO{sub 2}, which has a typical Delafossite structure with a weak antiferromagnetism and an exceptionally high in-plane electrical conductivity. Formation of PtCoO{sub 2} at the interface partially consumes the cobalt dopant and leads to the structural collapsing from 5 to 4 layers, which was confirmed by X-ray diffraction and high resolution transmission electron microscopy measurements. Considering the weak magnetic contribution from PtCoO{sub 2}, the observed ferromagnetism should be intrinsic of the Aurivillius compounds. Ferroelectric properties were also indicated by the piezoresponse force microscopy. In this work, the platinum induced secondary phase at the interface was observed, which has a strong impact on Aurivillius structural configuration and thus the ferromagnetic and ferroelectric properties.

  3. Optoelectronic method for determining platinum in biological products (United States)

    Radu, Simona; Ionicǎ, Mihai; Macovei, Radu Alexandru; Caragea, Genica; Forje, Mǎrgǎrita; Grecu, Iulia; Vlǎdescu, Marian; Viscol, Oana


    Of all platinum metals, platinum has the most uses and it's the most abundant and most easily to be processed. Its use in auto catalysts results in environmental contamination of crowded cities and high-traffic roads. In medicine, Pt is used as a cytostatic drug. In order to study the degree of contamination of the population with Pt or the correctness of treatment with Pt, it has been developed a method for its determination from urine or blood samples with a system Graphite Furnance - Atomic Absorption Spectrometer, (GF-AAS) Varian. There are presented the methods of sampling processing for blood or urine that followed the digest of the organic matrix. In the determination of the operating parameters for the system GF-AAS, was aimed the reducing of the nonanatomic absorbance by optimizing the drying temperatures, the calcination and atomization temperatures and the removal of the nonanatomic absorbance with D2 lamp. As a result of the use of the method are presented the concentrations of Pt in the blood or urine of a group of patients in Bucharest, a city with heavy traffic of vehicles. GF-AAS method presented is sensitive, reproducible, and relatively easy to apply with an acceptable cost. With this method, the concentration of Pt can be determined from blood and urine, both in order to establish the degree of contamination with Pt and for monitoring cancer therapy with platinum compounds.


    Emission models developed using small chamber data were combined with an Indoor Air Quality (IAQ) model to analyze the impact of volatile organic compound (VOC) emissions from latex paint on indoor environments. Test house experiments were conducted to verify the IAQ model's pred...

  5. Optimization and prevalidation of the in vitro ER alpha CALUX method to test estrogenic and antiestrogenic activity of compounds

    NARCIS (Netherlands)

    Burg, van der B.; Winter, R.; Weimer, M.; Berckmans, P.; Suzuki, G.; Gijsbers, L.; Jonas, A.; Linden, van der S.; Witters, H.; Aarts, J.M.M.J.G.; Legler, J.; Kopp-Schneider, A.; Bremer, S.


    Estrogenicity of chemicals has received significant attention and is linked to endocrine-disrupting activities. However, there is a paucity of validated methods to assess estrogenicity in vitro. We have established a robust method to test estrogenic and antiestrogenic activity of compounds in vitro,

  6. Hydroisomerization of Ethylbenzene on Mordenite-Based Bifunctional Catalysts with Different Platinum Contents

    Directory of Open Access Journals (Sweden)

    Fernandes L.D.


    Full Text Available A commercial Na-mordenite sample underwent ion exchange with HCl. The ion-exchanged sample was sequentially submitted to hydrothermal treatments at 823, 873 and 923 K, each followed by acid leaching of the extraframework alumina (EFAL generated. Six mordenite samples, presenting different framework and extraframework compositions, were obtained. These samples were used to prepare bifunctional catalysts by mixing them with Pt/Al2O3 in different proportions. The generated samples presented distinct platinum contents and were tested in the hydroisomerization reaction of ethylbenzene. A maximum xylene selectivity at about 0.45 wt% of platinum was observed. Normally, the total activity increased as the platinum content increased; this effect was more pronounced in the samples which presented lower mesoporosity. The most dealuminated sample, which presented a high mesoporosity, did not show any change in activity with the increase in platinum content.

  7. Phase I trials of WR-2721 and cis-platinum

    Energy Technology Data Exchange (ETDEWEB)

    Glover, D.; Glick, J.H.; Weiler, C.; Yuhas, J.; Kligerman, M.M.


    WR-2721 is a sulfhydryl compound which in the animal model improves renal tolerance to cis-platinum (DDP) by factors of 1.3 to 1.7. Phase I trials were initiated to establish the toxicity and dose modification factor when WR-2721 was given prior to escalating doses of DDP. Nineteen patients received 27 courses of WR-2721 (450-910 mg/m/sup 2/) 20 minutes prior to DDP (50-120 mg/m/sup 2/). Mild, transient nephrotoxicity was observed in only 2 of 15 courses of DDP 80-100 mg/m/sup 2/ when WR-2721 was given prior to DDP. Although 5 of 9 patients treated with WR-2721 prior to 120 mg/m/sup 2/ of DDP developed transient nephrotoxicity, their serum creatinines returned to normal baseline values within 1 to 2 weeks. Thirty-four courses of WR-2721 (740 mg/m/sup 2/) prior to DDP 120-150 mg/m/sup 2/ with mannitol diuresis were administered. Biweekly serum creatinine and monthly creatinine clearances have remained normal in all patients treated with 120 mg/m/sup 2/ of platinum and WR-2721. Four of 10 patients treated with 150 mg/m/sup 2/ of cis-platinum experienced transient nephrotoxicity 5-7 days after treatment. Mild ototoxicity was noted in 4 patients following 150 mg/m/sup 2/ of DDP. WR-2721 does not appear to protect against the antitumor efficacy of DDP. Compared to retrospective series, our data suggest that WR-2721 may provide some protection against platinum-induced nephrotoxicity, but the dose modification factors remain to be established.

  8. Synthesis and polarized photoluminescence of novel phosphorescent cyclometalated platinum dimer

    Institute of Scientific and Technical Information of China (English)

    Shi Ping Jiang; Kai Jun Luo; Ying Han Wang; Xin Wang; Ying Jiang; Yan Yan Wei


    A novel phosphorescent cyclometalated platinum dimer with bis-[2-(p-dodecyloxyphenyl) pyridyl]-hexane-l,6-diol as ligand and 1,3-( 1-n-hexyl,3-n-heptadecyl) diketone as ancillary ligand was synthesized. The chemical structure and liquid crystal property of the dimer were characterized by 1H NMR, ESI-MS, polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). The aligned film of title compound on the rubbed polyimide film is intensely emissive at room temperature with emission maximum at 516 nm. The luminescence dichroic ratio (I∥/ IL) at 516 nm is 3.1.

  9. Synthesis and characterization of novel platinum acetylide oligomers (United States)

    Cooper, Thomas M.; Krein, Douglas M.; Burke, Aaron R.; McLean, Daniel G.; Rogers-Haley, Joy E.; Slagle, Jonathan; Monahan, Jennifer; Urbas, Augustine


    To learn about excited state geometry in biphenyl-containing platinum acetylides, we synthesized a series of compounds that have biphenyl ligands. The ligands consisted of biphenyl(I), the hindered 2'-methyl biphenyl(III) and planar fluorenyl(IV) groups. We also synthesized a "half" complex(II) consisting of one ligand attached to the platinum atom. The optical properties of these compounds were measured by ground state absorption, phosphorescence, ultrafast transient absorption and nanosecond transient absorption spectroscopy. DFT calculations were performed to determine the ground state and triplet state geometries and the lowest triplet energy. TDDFT calculations were performed to determine singlet excited state energies. Compared to the reference compound I, ground state spectra show a blue shift in II and III and red shift in IV, showing the singlet energy is sensitive to conjugation and biphenyl twist angle. Comparison of the phosphorescence spectra of I and II shows the triplet exciton is confined to one ligand. The time behavior of the ultrafast excited state absorption spectrum of I shows a red shift within 1 ps from the initial spectrum. This behavior is not seen in IV. The different behavior suggests formation of the triplet state of I is accompanied by conversion from a non-planar to a planar conformation while IV retains a planar conformation.

  10. Process for applying a catalytically active coating, particularly one containing platinum and/or palladium on catalyst carrier. Verfahren zum Aufbringen eines katalytisch aktiven, insbesondere Platin und/oder Palladium enthaltenden Ueberzugs auf Katalysatortraeger

    Energy Technology Data Exchange (ETDEWEB)

    Bozon, A.; Lakatos, E.; Koberstein, E.; Pletka, H.D.; Voelker, H.


    The invention concerns an improved process for applying a platinum and/or palladium, coating or films, possibly one containing other platinum group metals and/or nonprecious metals, by means of solutions of the metal compounds on the outer surface of porous catalyst carriers, i.e. those having a large surface. It was found that aquaeous solutions of ammonium chloride can be used to advantage to pre-charge the catalyst carrier, instead of the previously used organic solvents, where the saturation of the catalyst carrier must not be exceeded. After impregnation with an aquaeous solution of the catalytically active elements, the liquid is finally removed by heating. In the engine exhaust gas test, the catalysts according to the invention proved superior to the conventional ones.

  11. Determination of the In Vitro and In Vivo Activity of Compounds Tested Against Punta Toro Virus (United States)


    Bryostatin 1 qd x 5 iLp. >1444"g/ko/day once only i.p. >200 4Ig/kg 2713 Bryostatin 2 qd x 5 i.p. >36 pjg’t/gd4y 2741 1-(B-D-ribofuranosyl)-1,2,4-triazole-3...only. We conclude two compounds were sent to us, with that in vial #1 being active. AVS2712 ( Bryostatin 1) (Tables V-70--V-74): This material was...different dosages, suggesting a duo mechanism of action or an immunomodulating effect with the compound. 39 AVS2713 ( Bryostatin 2) (Tables V-75, V-76): No

  12. Comparison of the effects of the oral anticancer platinum(IV) complexes oxoplatin and metabolite cis-diammine-tetrachlorido-platinum(IV) on global gene expression of NCI-H526 cells. (United States)

    Olszewski, Ulrike; Ulsperger, Ernst; Geissler, Klaus; Hamilton, Gerhard


    Platinum(IV) coordination complexes like oxoplatin (cis,cis,trans-diammine-dichlorido-dihydroxido-platinum[IV]) show high stability and therefore can be utilized orally for outpatient care. Although oxoplatin is capable of binding directly to DNA after prolonged incubation, platinum(IV) agents are considered to be largely inert prodrugs that are converted to highly cytotoxic platinum(II) compounds by reducing substances, enzymes, or microenviron-mental conditions. Reaction of oxoplatin with 0.1 M hydrogen chloride mimicking gastric acid yields cis-diammine-tetrachlorido-platinum(IV) (DATCP[IV]), which exhibits two-fold increased activity. The presence of chlorides as ligands in the axial position results in a high reduction potential that favors transformation to platinum(II) complexes. In this study, the intracellular effect of the highly reactive tetrachlorido derivative was investigated in comparison with an equipotent dose of cisplatin. Genome-wide expression profiling of NCI-H526 small cell lung cancer cells treated with these platinum species revealed clear differences in the expression pattern of affected genes and concerned cellular pathways between DATCP(IV) and cisplatin. Application of DATCP(IV) resulted in extensive downregulation of protein and ATP synthesis, cell cycle regulation, and glycolysis, in contrast to cisplatin, which preferentially targeted glutathione conjugation, pyruvate metabolism, citric acid cycle, and the metabolism of amino acids and a range of carbohydrates. Thus, the oxoplatin metabolite DATCP(IV) constitutes a potent cytotoxic derivative that may be produced by gastric acid or acidic areas prevailing in larger solid tumors, depending on the respective pharmaceutical formulation of oxoplatin. Furthermore, DATCP(IV) exhibits intracellular effects that are clearly different from the expected reduced product cisplatin(II). In conclusion, activation of the platinum(IV) complex oxoplatin seems to involve the generation of a cytotoxic

  13. Inhibition of Notch signaling in combination with paclitaxel reduces platinum-resistant ovarian tumor growth

    Directory of Open Access Journals (Sweden)

    Jolijn W Groeneweg


    Full Text Available Introduction: Ovarian cancer (OvCa is the most lethal gynecologic malignancy in the United States because of chemoresistant recurrent disease. Our objective was to investigate the efficacy of inhibiting the Notch pathway with a gamma-secretase inhibitor (GSI in an OvCa patient derived xenograft (PDX model as a single agent therapy and in combination with standard chemotherapy.Methods: Immunocompromised mice bearing xenografts derived from clinically platinum sensitive human ovarian serous carcinomas were treated with vehicle, GSI (MRK-003 alone, paclitaxel and carboplatin (P/C alone, or the combination of GSI and P/C. Mice bearing platinum resistant xenografts were given GSI with or without paclitaxel. Gene transcript levels of the Notch pathway target Hes1 were analyzed using RT-PCR. Notch1 and Notch3 protein levels were evaluated. The Wilcoxon rank-sum test was used to assess significance between the different treatment groups. Results: Expression of Notch1 and 3 was variable. GSI alone decreased tumor growth in two of three platinum sensitive ovarian tumors (p < 0.05, as well as in one of three platinum sensitive tumors (p = 0.04. The combination of GSI and paclitaxel was significantly more effective than GSI alone and paclitaxel alone in all platinum resistant ovarian tumors (all p <0.05. The addition of GSI did not alter the effect of P/C in platinum sensitive tumors. Interestingly, although the response of each tumor to chronic GSI exposure did not correlate with its endogenous level of Notch expression, GSI did negatively affect Notch signaling in an acute setting.Conclusions: Inhibiting the Notch signaling cascade with a GSI reduces primary human xenograft growth in vivo. GSI synergized with conventional cytotoxic chemotherapy only in the platinum resistant OvCa models with single agent paclitaxel. These findings suggest inhibition of the Notch pathway in concert with taxane therapy may hold promise for treatment of platinum resistant OvCa.

  14. In-vitro thrombogenicity assessment of polymer filament modified and native platinum embolic coils. (United States)

    Girdhar, Gaurav; Read, Megan; Sohn, Jihae; Shah, Chirag; Shrivastava, Sanjay


    Embolic coils have been used to treat intracranial aneurysms using an endovascular approach for more than two decades. However, significant aneurysm recanalization rates have been reported specifically in large and giant aneurysms. Adding filaments to bare Platinum coils is considered a modification and has been proposed to achieve higher aneurysm occlusion rates as compared to bare Platinum coils. Quantitative information - in terms of thrombin generation potential of these modifications - is however lacking. We report here in vitro thrombogenicity of Platinum coils containing Nylon (Axium™ MicroFx™ Nylon coil) and PGLA (Axium™ MicroFx™ PGLA coil) filaments and compare them with equivalent bare Platinum Axium™ coils. We utilize a quantitative method that tracks the formation of thrombin upon exposure of the test samples to human platelet rich plasma using a slow binding fluorogenic substrate. We report a significant increase in the total thrombin turnover, the peak thrombin amount and the rate of thrombin generation for the Axium™ MicroFx™ coils and filaments compared to the Axium™ coils and Platinum wire. Nylon and PGLA filaments added to bare Platinum coils increase thrombogenicity of coils. This study offers a robust quantitative method to compare thrombus formation efficacy of embolic coils under static conditions. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Electrodeposition of platinum-iridium alloy nanowires for hermetic packaging of microelectronics. (United States)

    Petrossians, Artin; Whalen, John J; Weiland, James D; Mansfeld, Florian


    An electrodeposition technique was applied for fabrication of dense platinum-iridium alloy nanowires as interconnect structures in hermetic microelectronic packaging to be used in implantable devices. Vertically aligned arrays of platinum-iridium alloy nanowires with controllable length and a diameter of about 200 nm were fabricated using a cyclic potential technique from a novel electrodeposition bath in nanoporous aluminum oxide templates. Ti/Au thin films were sputter deposited on one side of the alumina membranes to form a base material for electrodeposition. Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) were used to characterize the morphology and the chemical composition of the nanowires, respectively. SEM micrographs revealed that the electrodeposited nanowires have dense and compact structures. EDS analysis showed a 60:40% platinum-iridium nanowire composition. Deposition rates were estimated by determining nanowire length as a function of deposition time. High Resolution Transmission Electron Microscopy (HRTEM) images revealed that the nanowires have a nanocrystalline structure with grain sizes ranging from 3 nm to 5 nm. Helium leak tests performed using a helium leak detector showed leak rates as low as 1 × 10(-11) mbar L s(-1) indicating that dense nanowires were electrodeposited inside the nanoporous membranes. Comparison of electrical measurements on platinum and platinum-iridium nanowires revealed that platinum-iridium nanowires have improved electrical conductivity.

  16. Mixed copper-platinum complex formation could explain synergistic antiproliferative effect exhibited by binary mixtures of cisplatin and copper-1,10-phenanthroline compounds: An ESI-MS study. (United States)

    Pivetta, Tiziana; Lallai, Viola; Valletta, Elisa; Trudu, Federica; Isaia, Francesco; Perra, Daniela; Pinna, Elisabetta; Pani, Alessandra


    Cisplatin, cis-diammineplatinum(II) dichloride, is a metal complex used in clinical practice for the treatment of cancer. Despite its great efficacy, it causes adverse reactions and most patients develop a resistance to cisplatin. To overcome these issues, a multi-drug therapy was introduced as a modern approach to exploit the drug synergy. A synergistic effect had been previously found when testing binary combinations of cisplatin and three copper complexes in vitro, namely, Cu(phen)(OH2)2(OClO3)2, [Cu(phen)2(OH2)](ClO4)2 and [Cu(phen)2(H2dit)](ClO4)2,(phen=1,10-phenanthroline, H2dit=imidazolidine-2-thione), against the human acute T-lymphoblastic leukaemia cell line (CCRF-CEM). In this work [Cu(phen)2(OH2)](ClO4)2 was also tested in combination with cisplatin against cisplatin-resistant sublines of CCRF-CEM (CCRF-CEM-res) and ovarian (A2780-res) cancer cell lines. The tested combinations show a synergistic effect against both the types of resistant cells. The possibility that this effect was caused by the formation of new adducts was considered and mass spectra of solutions containing cisplatin and one of the three copper complexes at a time were measured using electrospray ionisation at atmospheric-pressure mass spectrometry (ESI-MS). A mixed complex was detected and its stoichiometry was assessed on the basis of the isotopic pattern and the results of tandem mass spectrometry experiments. The formed complex was found to be [Cu(phen)(OH)μ-(Cl)2Pt(NH3)(H2O)](+).

  17. Platinum (IV)-fatty acid conjugates overcome inherently and acquired Cisplatin resistant cancer cell lines: an in-vitro study. (United States)

    Ratzon, Einav; Najajreh, Yousef; Salem, Rami; Khamaisie, Hazem; Ruthardt, Martin; Mahajna, Jamal


    Platinum-based drugs are used as cancer chemotherapeutics for the last 40 years. However, drug resistance and nephrotoxicity are the major limitations of the use of platinum-based compounds in cancer therapy. Platinum (IV) complexes are believed to act as platinum prodrugs and are able to overcome some of platinum (II) limitations. A number of previously sensitized platinum (IV) complexes were evaluated for their anti-cancer activity by monitoring ability to affect proliferation, clonigenicity and apoptosis induction of Cisplatin sensitive and resistant cancer cells. In addition, the uptake of Cisplatin and the platinum (IV) derivatives to Cisplatin sensitive and resistant cancer cells was monitored. The bis-octanoatoplatinum (IV) complex (RJY13), a Cisplatin derivative with octanoate as axial ligand, exhibited strong anti-proliferative effect on the Cisplatin resistant and sensitive ovarian cells, A2780cisR and A2780, respectively. Moreover, RJY13 exhibited good activity in inhibiting clonigenicity of both cells. Anti-proliferative activity of RJY13 was mediated by induction of apoptosis. Interestingly, a bis-lauratopaltinum (IV) complex (RJY6) was highly potent in inhibiting clonigenicity of both Cisplatin sensitive and Cisplatin resistant cells, however, exhibited reduced activity in assays that utilize cells growing in two dimensional (2D) conditions. The uptake of Cisplatin was reduced by 30% in A2780 in which the copper transporter-1 (Ctr1) was silenced. Moreover, uptake of RJY6 was marginally dependent on Ctr1, while uptake of RJY13 was Ctr1-independent. Our data demonstrated the potential of platinum (IV) prodrugs in overcoming acquired and inherited drug resistance in cancer cell lines. Moreover, our data demonstrated that the uptake of Cisplatin is partially dependent on Ctr1 transporter, while uptake of RJY6 is marginally dependent on Ctr1 and RJY13 is Ctr1-independent. In addition, our data illustrated the therapeutic potential of platinum (IV) prodrugs

  18. Organo-platinum complexes as antitumor agents (review). (United States)

    Hill, J M; Speer, R J


    Rosenberg et al discovered in the coordination complexes of platinum a new, novel type of potential antitumor agent. Cisplatin [cis-dichlorodiammine platinum (II)4 proved active against a variety of rodent tumors and acted synergistically when combined with other chemotherapeutic agents. Initial clinical tests by Hill et al in 1971, showed cisplatin to be active against malignant lymphoma, Hodgkin's disease, and certain other malignancies. Significant nephrotoxicity, nausea, and vomiting were noted. Since then, cisplatin has been tested alone and in combination chemotherapy and has proven an efficacious anticancer agent in squamous cell carcinoma of head and neck, ovarian carcinoma, disseminated testicular cancer, and others. Its therapeutic value was acknowledged when approved in 1978 by the U.S. FDA for treatment of the latter cancer. The current clinical literature indicates clearly that the full potential of this drug has not yet been realized. Hydration and diuresis have served to mitigate much of the nephrotoxicity, while significant strides toward amelioration of the nausea and vomiting have also been achieved. Literally, thousands of chemically-related congeners have been synthesized, and many have shown marked potency against rodent tumors. Very few, however, have been evaluated clinically, vis-a-vis malonato trans(-)-1,2-diaminocyclohexane platinum(II); this appears a most promising and fertile area of future investigation.

  19. Aberrant DNA damage response pathways may predict the outcome of platinum chemotherapy in ovarian cancer.

    Directory of Open Access Journals (Sweden)

    Dimitra T Stefanou

    Full Text Available Ovarian carcinoma (OC is the most lethal gynecological malignancy. Despite the advances in the treatment of OC with combinatorial regimens, including surgery and platinum-based chemotherapy, patients generally exhibit poor prognosis due to high chemotherapy resistance. Herein, we tested the hypothesis that DNA damage response (DDR pathways are involved in resistance of OC patients to platinum chemotherapy. Selected DDR signals were evaluated in two human ovarian carcinoma cell lines, one sensitive (A2780 and one resistant (A2780/C30 to platinum treatment as well as in peripheral blood mononuclear cells (PBMCs from OC patients, sensitive (n = 7 or resistant (n = 4 to subsequent chemotherapy. PBMCs from healthy volunteers (n = 9 were studied in parallel. DNA damage was evaluated by immunofluorescence γH2AX staining and comet assay. Higher levels of intrinsic DNA damage were found in A2780 than in A2780/C30 cells. Moreover, the intrinsic DNA damage levels were significantly higher in OC patients relative to healthy volunteers, as well as in platinum-sensitive patients relative to platinum-resistant ones (all P<0.05. Following carboplatin treatment, A2780 cells showed lower DNA repair efficiency than A2780/C30 cells. Also, following carboplatin treatment of PBMCs ex vivo, the DNA repair efficiency was significantly higher in healthy volunteers than in platinum-resistant patients and lowest in platinum-sensitive ones (t1/2 for loss of γH2AX foci: 2.7±0.5h, 8.8±1.9h and 15.4±3.2h, respectively; using comet assay, t1/2 of platinum-induced damage repair: 4.8±1.4h, 12.9±1.9h and 21.4±2.6h, respectively; all P<0.03. Additionally, the carboplatin-induced apoptosis rate was higher in A2780 than in A2780/C30 cells. In PBMCs, apoptosis rates were inversely correlated with DNA repair efficiencies of these cells, being significantly higher in platinum-sensitive than in platinum-resistant patients and lowest in healthy volunteers (all P<0.05. We conclude

  20. Characterization of electrochemically modified polycrystalline platinum surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Krebs, L.C.; Ishida, Takanobu.


    The characterization of electrochemically modified polycrystalline platinum surfaces has been accomplished through the use of four major electrochemical techniques. These were chronoamperometry, chronopotentiommetry, cyclic voltammetry, and linear sweep voltammetry. A systematic study on the under-potential deposition of several transition metals has been performed. The most interesting of these were: Ag, Cu, Cd, and Pb. It was determined, by subjecting the platinum electrode surface to a single potential scan between {minus}0.24 and +1.25 V{sub SCE} while stirring the solution, that the electrocatalytic activity would be regenerated. As a consequence of this study, a much simpler method for producing ultra high purity water from acidic permanganate has been developed. This method results in water that surpasses the water produced by pyrocatalytic distillation. It has also been seen that the wettability of polycrystalline platinum surfaces is greatly dependent on the quantity of oxide present. Oxide-free platinum is hydrophobic and gives a contact angle in the range of 55 to 62 degrees. We have also modified polycrystalline platinum surface with the electrically conducting polymer poly-{rho}-phenylene. This polymer is very stable in dilute sulfuric acid solutions, even under applied oxidative potentials. It is also highly resistant to electrochemical hydrogenation. The wettability of the polymer modified platinum surface is severely dependent on the choice of supporting electrolyte chosen for the electrochemical polymerization. Tetraethylammonium tetrafluoroborate produces a film that is as hydrophobic as Teflon, whereas tetraethylammonium perchlorate produces a film that is more hydrophilic than oxide-free platinum.

  1. Unsaturated platinum-rhenium cluster complexes. Synthesis, structures and reactivity. (United States)

    Adams, Richard D; Captain, Burjor; Smith, Mark D; Beddie, Chad; Hall, Michael B


    Two new compounds PtRe3(CO)12(PBut3)(micro-H)3, 9, and PtRe2(CO)9(PBut3)(micro-H)2, 10, were obtained from the reaction of Pt(PBut3)2 with Re3(CO)12(micro-H3), 8, at room temperature. Compound 9 contains a butterfly cluster of four metals formed by the insertion of the platinum atom from a Pt(PBut3) group into one of the hydride-bridged metal-metal bonds of 8. The three hydrido ligands are bridging ligands across each of three new Pt-Re bonds. Compound 10 contains a triangular PtRe2 cluster with two hydrido ligands; one bridges a Pt-Re bond, and the other bridges the Re-Re bond. The new compound Pt2Re2(CO)7(PBut3)2(micro-H)2, 11, was obtained from the reaction of 8 with Pt(PBut3)2 in hexane at reflux. Compound 11 was also obtained from 10 by reaction with an additional quantity of Pt(PBut3)2. Compound 11 contains a tetrahedral cluster of four metal atoms with two dynamically active hydrido ligands. A CO ligand on one of the two platinum atoms also exchanges between the two platinum atoms rapidly on the NMR time scale. Compound 11 is electronically unsaturated and was found to add hydrogen at room temperature to form the tetrahydrido cluster complex, Pt2Re2(CO)7(PBut3)2(micro-H)4, 12. Compound 12 has a structure similar to 11 but contains one triply bridging hydrido ligand, two edge bridging hydrido ligands, and one terminal hydrido ligand on one of the two platinum atoms. A kinetic isotope effect D/H of 1.5(1) was determined for the addition of H2 to 11. Hydrogen can be eliminated from 12 by heating to 97 degrees C or by the application of UV-vis irradiation at room temperature. Compound 12 adds CO at room temperature to yield the complex Pt2Re2(CO)8(PBut3)2(micro-H)4, 13, which contains a planar cluster of four metal atoms with a Pt-Pt bond and four edge bridging hydrido ligands. Compounds 11 and 12 react with Pt(PBut3)2 to yield the known five metal cluster complexes Pt3Re2(CO)6(PBut3)3(micro-H)2, 14, and Pt3Re2(CO)6(PBut3)3(micro-H)4, 15, respectively. Density

  2. Effects of platinum in biological systems - toxicology and pharmaceutical applications; Wirkungen von Platin in biologischen Systemen - Toxikologie und pharmazeutische Anwendung

    Energy Technology Data Exchange (ETDEWEB)

    Nachtigall, D. [Fraunhofer-Institut fuer Toxikologie und Aerosolforschung, Hannover (Germany)


    The title of this lecture has intentionally been worded rather vaguely with ``biological systems`` to do justice to the fact that there are meanwhile extensive data available on diverse levels of the toxicology and structure-effect relationships of some platinum compounds. These range from epidemiological descriptions over toxicity studies to molecular biological reaction mechanisms. Any discussion on the toxicity of a substance implies that the substance poses a direct or indirect hazard to humans. In the case of platinum and its compounds there are three main categories of exposure: platinum production including workplaces in the platinum processing industries; clinical treatment with antineoplastic platinum-containing agents; and, finally, the environment, where platinum levels are known to be rising since some years. The association between these exposures becomes clear when one considers the platinum pollution caused by automobile catalytic converters, hospital effluents, and by platinum-containing industrial products in the widest sense. [Deutsch] Der Titel des Vortrages ist mit `biologischen Systemen` sehr allgemein gehalten, da ueber die Toxikologie und die Struktur-Wirkungsbeziehungen einiger Platinverbindungen auf den verschiedensten Ebenen umfangreiche Daten vorliegen. Diese reichen von epidemiologischen Beschreibungen ueber Toxizitaetsstudien bis hin zu molekularbiologischen Reaktionsmechanismen. Die Diskussion um die Toxizitaet von Substanzen impliziert immer die direkte oder indirekte Gefaehrdung des Menschen. Im Falle des Platins und seiner Verbindungen existieren drei wesentliche Expositionsbereiche: Die Platingewinnung sowie die Arbeitsplaetze in der Platin verarbeitenden Industrie, die klinische Behandlung mit antineoplastischen Platinwirkstoffen und schliesslich die Umwelt, in der seit einigen Jahren ansteigende Platinkonzentrationen verzeichnet werden. Die Verbindung zwischen diesen Bereichen wird deutlich, wenn man die Platinimmissionen durch

  3. Design, Synthesis of Novel Platinum(II) Glycoconjugates, and Evaluation of Their Antitumor Effects. (United States)

    Han, Jianbin; Gao, Xiangqian; Liu, Ran; Yang, Jinna; Zhang, Menghua; Mi, Yi; Shi, Ying; Gao, Qingzhi


    A new series of sugar-conjugated (trans-R, R-cyclohexane-1, 2-diamine)-2-halo-malonato-platinum(II) complexes were designed and synthesized to target tumor-specific glucose transporters (GLUTs). The water solubility of the sugar-conjugated platinum (II) complexes was greatly improved by average of 570-fold, 33-fold, and 94-fold, respectively, compared to cisplatin (1.0 mg/mL), carboplatin (17.1 mg/mL), and the newest generation of clinical drug oxaliplatin (6.0 mg/mL). Despite the high water solubility, the platinum(II) glycoconjugates exhibited a notable increase in cytotoxicity by a margin of 1.5- to 6.0-fold in six different human cancer cell lines with respect to oxaliplatin. The potential GLUT1 transportability of the complexes was investigated through a molecular docking study and was confirmed with GLUT1 inhibitor-mediated cytotoxicity dependency evaluation. The results showed that the sugar-conjugated platinum(II) complexes can be recognized by the glucose recognition binding site of GLUT1 and their cell killing effect depends highly on the GLUT1 inhibitor, quercetin. The research presenting a prospective concept for targeted therapy anticancer drug design, and with the analysis of the synthesis, water solubility, antitumor activity, and the transportability of the platinum(II) glycoconjugates, this study provides fundamental data supporting the inherent potential of these designed conjugates as lead compounds for GLUT-mediated tumor targeting.

  4. A Photoactivatable Platinum(IV) Anticancer Complex Conjugated to the RNA Ligand Guanidinoneomycin. (United States)

    Shaili, Evyenia; Fernández-Giménez, Marta; Rodríguez-Astor, Savina; Gandioso, Albert; Sandín, Lluís; García-Vélez, Carlos; Massaguer, Anna; Clarkson, Guy J; Woods, Julie A; Sadler, Peter J; Marchán, Vicente


    A photoactivatable platinum(IV) complex, trans,trans,trans-[Pt(N3 )2 (OH)(succ)(py)2 ] (succ=succinylate, py=pyridine), has been conjugated to guanidinoneomycin to study the effect of this guanidinum-rich compound on the photoactivation, intracellular accumulation and phototoxicity of the pro-drug. Surprisingly, trifluoroacetic acid treatment causes the replacement of an azido ligand and the axial hydroxide ligand by trifluoroacetate, as shown by NMR spectroscopy, MS and X-ray crystallography. Photoactivation of the platinum-guanidinoneomycin conjugate in the presence of 5'-guanosine monophosphate (5'-GMP) led to the formation of trans-[Pt(N3 )(py)2 (5'-GMP)](+) , as does the parent platinum(IV) complex. Binding of the platinum(II) photoproduct {PtN3 (py)2 }(+) to guanine nucleobases in a short single-stranded oligonucleotide was also observed. Finally, cellular uptake studies showed that guanidinoneomycin conjugation improved the intracellular accumulation of the platinum(IV) pro-drug in two cancer cell lines, particularly in SK-MEL-28 cells. Notably, the higher phototoxicity of the conjugate in SK-MEL-28 cells than in DU-145 cells suggests a degree of selectivity towards the malignant melanoma cell line.

  5. Synthesis and Analysis of the Structure, Diffusion and Cytotoxicity of Heterocyclic Platinum(IV) Complexes. (United States)

    Macias, Freddy J; Deo, Krishant M; Pages, Benjamin J; Wormell, Paul; Clegg, Jack K; Zhang, Yingjie; Li, Feng; Zheng, Gang; Sakoff, Jennette; Gilbert, Jayne; Aldrich-Wright, Janice R


    We have developed six dihydroxidoplatinum(IV) compounds with cytotoxic potential. Each derived from active platinum(II) species, these complexes consist of a heterocyclic ligand (HL) and ancillary ligand (AL) in the form [Pt(HL)(AL)(OH)2](2+), where HL is a methyl-functionalised variant of 1,10-phenanthroline and AL is the S,S or R,R isomer of 1,2-diaminocyclohexane. NMR characterisation and X-ray diffraction studies clearly confirmed the coordination geometry of the octahedral platinum(IV) complexes. The self-stacking of these complexes was determined using pulsed gradient stimulated echo nuclear magnetic resonance. The self-association behaviour of square planar platinum(II) complexes is largely dependent on concentration, whereas platinum(IV) complexes do not aggregate under the same conditions, possibly due to the presence of axial ligands. The cytotoxicity of the most active complex, exhibited in several cell lines, has been retained in the platinum(IV) form.

  6. Combined chemotherapy including platinum derivatives for medulloblastoma. The usefulness as maintenance chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Hikaru; Otani, Mitsuhiro; Yoshida, Kazunari; Kagami, Hiroshi; Shimazaki, Kenji; Toya, Shigeo; Kawase, Takeshi [Keio Univ., Tokyo (Japan). School of Medicine


    The authors reviewed 24 cerebellar medulloblastoma patients treated at Keio University to determine usefulness of combined chemotherapy including platinum derivatives (cisplatin, carboplatin) as the induction and maintenance treatment. All patients underwent radical surgery and craniospinal irradiation. Ten received adjuvant chemotherapy other than platinum derivatives (mainly with nitrosourea compounds), five were treated by induction and maintenance chemotherapy including platinum derivatives, and nine patients did not undergo chemotherapy. The progression-free survival rate of patients treated with platinum derivatives was better than that of patients treated with other modes of chemotherapy and also that of patients who did not receive chemotherapy. The results were especially good in the case of four patients treated with maintenance chemotherapy consisting of carboplatin and etoposide, two of whom had been free from relapse beyond the risk period of Collins. The occurrences of toxicity in maintenance chemotherapy with carboplatin and etoposide were limited to transient leucopenia. The present study indicates combined chemotherapy including platinum derivatives benefits patients with medulloblastoma, and could be useful, especially as maintenance treatment. (author)

  7. Determination of the In Vitro and In Vivo Activity of Compounds Tested Against Punta Toro Virus. (United States)


    survivors per total and increased numbers of serum samples having negative SGOT and SGPT values were evaluated using chi square analysis with Yate’s...glutamic oxalic acid transaminase (SGOT) and serum glutamic pyruvic acid transaminase ( SGPT ). Overall, 155 experiments were run on these compounds and...0.2 ml of one- half log10 virus dilutions subcutaneously (s.c.) into 3 week-old mice. As seen in Table I-1, the LD50 values did not vary appreciably

  8. Determination of the In Vitro and In Vivo Activity of Compounds Tested against Punta Toro Virus (United States)


    by Biological Research Faculty and Facility, Inc. (Rockville, MD). Compounds synthesized by Pharmatek, Inc. were especially prepared using...without stopping the deaminase reaction and dried at room temperature for 15 minutes. Plates were developed with 2- propanoi-aqueous ammonia (fresh...dry overnight to eliminate any traces of free ammonia . Plates were placed in a 2000 ml beaker layered with a 0.5 cm layer of CaHCI03, covered, and

  9. Volatile Organic Compound (VOC) Testing at Building 348, Kelly AFB, Texas. (United States)


    At the request of HQ AFLC/ SGB , the USAFOEHL conducted a stack sampling survey to determine total volatile organic compounds (VOC) being emitted from...Occupational and Environmental Health Laboratory (USAFOEHL/ECQ). The survey was requested by HQ AFLC/ SGB .to estimate VOC emissions through each of...stardards. 2. Range and Sensitivity 2.1 This method was validated over the range of 1417-5940 mg/M at an atmospheric temperature and pressure of 24 0C

  10. Room temperature synthesis of colloidal platinum nanoparticles

    Indian Academy of Sciences (India)

    G Sarala Devi; V J Rao


    Efficient preparation of stable dispersions of platinum nanoparticles from platinous chloride (K2PtCl4) was achieved by simultaneous addition of capping polymer material. The size of platinum nanoparticles was controlled by changing the ratio of concentration of capping polymer material to the concentration of platinum cation used. The morphology of colloidal particles were studied by means of UV-visible spectrophotometry and transmission electron microscopy (TEM). Particle size increased with low reagent concentration. The change in absorption spectra with the particle size was observed, i.e. blue shift attributed to decrease in particle size.

  11. Antitumor effect of arabinogalactan and platinum complex. (United States)

    Starkov, A K; Zamay, T N; Savchenko, A A; Ingevatkin, E V; Titova, N M; Kolovskaya, O S; Luzan, N A; Silkin, P P; Kuznetsova, S A


    The article presents the results of investigation of antitumor properties of platinum-arabinogalactan complex. We showed the ability of the complex to inhibit the growth of Ehrlich ascites tumor cells. It is found that the distribution of the platinum-arabinogalactan complex is not specific only for tumor cells in mice. The complex was found in all tissues and organs examined (ascites cells, embryonic cells, kidney, and liver). The mechanism of action of the arabinogalactan-platinum complex may be similar to cisplatin as the complex is able to accumulate in tumor cells.

  12. Mechanism of Platinum Derivatives Induced Kidney Injury

    Directory of Open Access Journals (Sweden)

    Feifei YAN


    Full Text Available Platinum derivatives are the most widely used chemotherapeutic agents to treat solid tumors including ovarian, head and neck, and testicular germ cell tumors, lung cancer, and colorectal cancer. Two major problems exist, however, in the clinic use of platinum derivatives. One is the development of tumor resistance to the drug during therapy, leading to treatment failure. The other is the drug’s toxicity such as the cisplatin’s nephrotoxicity, which limits the dose that can be administered. This paper describes the mechanism of platinum derivatives induced kidney injury.

  13. Polymer Optical Fiber Compound Parabolic Concentrator fiber tip based glucose sensor: In-Vitro Testing

    DEFF Research Database (Denmark)

    Hassan, Hafeez Ul; Janting, Jakob; Aasmul, Soren;


    We present in-vitro sensing of glucose using a newly developed efficient optical fiber glucose sensor based on a Compound Parabolic Concentrator (CPC) tipped polymer optical fiber (POF). A batch of 9 CPC tipped POF sensors with a 35 mm fiber length is shown to have an enhanced fluorescence pickup...... efficiency with an average increment factor of 1.7 as compared to standard POF sensors with a plane cut fiber tip. Invitro measurements for two glucose concentrations (40 and 400 mg/dL) confirm that the CPC tipped sensors efficiently can detect both glucose concentrations. it sets the footnote at the bottom...

  14. IRIS Toxicological Review of Halogenated Platinum Salts and Platinum Compounds (External Review Draft) (United States)

    EPA released the draft toxicological review for public comment under the Integrated Risk Information System (IRIS) Program. The original draft assessment (January 2009) has been archived but is available on this web page for the sake of transparency.

  15. Quality-Control Analytical Methods: Microbial-Testing Aspects of USP Chapter 797 for Compounded Sterile Preparations. (United States)

    Kupiec, Thomas C


    The standards set forth by the United States Pharmacopeia (USP) Chapter 797 have now been in effect since January 1 or 2004. As the first practice standards of sterile pharmacy compounding in US history, they have "attracted both respect and criticism" because they have also been cited as a practice expectation by the Joint Commission on Accreditation of Healthcare Organizations. USP 797 expands the scope of facilities governed by the regulatinos and defines the practices covered, emphasizing the importance of environmental quality and control, verification of accuracy and sterility, training and evaluation, quality control after preparations leave the pharmacy, patient monitoring and adverse events reporting. The purpose of this article is to help the reader understand the criteria set forth by USP Chapter 797 regarding finished-product testing, including criteria for the microbial-testing aspects of sterility testing (USP Chapter 71) and endotoxin (pyrogen) testing (USP Chapter 85).

  16. Platinum-Resistor Differential Temperature Sensor (United States)

    Kolbly, R. B.; Britcliffe, M. J.


    Platinum resistance elements used in bridge circuit for measuring temperature difference between two flowing liquids. Temperature errors with circuit are less than 0.01 degrees C over range of 100 degrees C.

  17. VB Platinum Tile & Carpet, Inc. Information Sheet (United States)

    VB Platinum Tile & Carpet, Inc. (the Company) is located in Bristow, Virginia. The settlement involves renovation activities conducted at a property constructed prior to 1978, located in Washington, DC.

  18. Simple cerium-triethanolamine complex: Synthesis, characterization, thermal decomposition and its application to prepare ceria support for platinum catalysts used in methane steam reforming (United States)

    Wattanathana, Worawat; Nootsuwan, Nollapan; Veranitisagul, Chatchai; Koonsaeng, Nattamon; Laosiripojana, Navadol; Laobuthee, Apirat


    Cerium-triethanolamine complex was synthesized by simple complexation method in 1-propanol solvent using cerium(III) chloride as a metal source and triethanolamine as a ligand. The structures of the prepared complex were proposed based on FT-IR, FT-Raman and ESI-MS results as equimolar of triethanolamine and cerium chelated complex having monomeric tricyclic structure with and without chloride anion as another coordinating group known as ceratrane. The complex was used as a precursor for ceria material done by thermal decomposition. XRD result revealed that when calcined at 600 °C for 2 h, the cerium complex was totally turned into pure ceria with cubic fluorite structure. The obtained ceria was then employed to synthesize platinum doped ceria catalysts for methane steam reforming. Various amounts of platinum i.e. 1, 3, 5 and 10 mol percents were introduced on the ceria support by microwave-assisted wetness impregnation using ammonium tetrachloroplatinate(II). The platinum-impregnated ceria powders were subjected to calcination in 10% hydrogen/helium atmosphere at 500 °C for 3 h to reduce platinum(II) to platinum(0). XRD patterns of the catalysts confirmed that the platinum particles doped on the ceria support were in the form of platinum(0). Catalytic activity test showed that the catalytic activities got higher as the amounts of platinum doped increased. Besides, the portions of coke formation on the surface of catalysts were reduced as the amounts of platinum doped increased.

  19. Stabilizing platinum in phosphoric acid fuel cells (United States)

    Remick, R. J.


    Platinum sintering on phosphoric acid fuel cell cathodes is discussed. The cathode of the phosphoric acid fuel cell uses a high surface area platinum catalyst dispersed on a conductive carbon support to minimize both cathode polarization and fabrication costs. During operation, however, the active surface area of these electrodes decreases, which in turn leads to decreased cell performance. This loss of active surface area is a major factor in the degradation of fuel cell performance over time.

  20. Primer towards an in vitro test for screening irritant potency of compounds

    NARCIS (Netherlands)

    Vandebriel RJ; Machielsen A; Bakker K; van Loveren H; LPI


    Het vaststellen van de allergene potentie van stoffen wordt in het algemeen uitgevoerd met behulp van de 'Buehler occluded patch test' en de 'guinea pig maximization test', terwijl de auriculaire lymfkliertest gebruikt wordt voor screening. Deze testen hebben veel informatie opg

  1. A new compound control method for sine-on-random mixed vibration test (United States)

    Zhang, Buyun; Wang, Ruochen; Zeng, Falin


    Vibration environmental test (VET) is one of the important and effective methods to provide supports for the strength design, reliability and durability test of mechanical products. A new separation control strategy was proposed to apply in multiple-input multiple-output (MIMO) sine on random (SOR) mixed mode vibration test, which is the advanced and intensive test type of VET. As the key problem of the strategy, correlation integral method was applied to separate the mixed signals which included random and sinusoidal components. The feedback control formula of MIMO linear random vibration system was systematically deduced in frequency domain, and Jacobi control algorithm was proposed in view of the elements, such as self-spectrum, coherence, and phase of power spectral density (PSD) matrix. Based on the excessive correction of excitation in sine vibration test, compression factor was introduced to reduce the excitation correction, avoiding the destruction to vibration table or other devices. The two methods were synthesized to be applied in MIMO SOR vibration test system. In the final, verification test system with the vibration of a cantilever beam as the control object was established to verify the reliability and effectiveness of the methods proposed in the paper. The test results show that the exceeding values can be controlled in the tolerance range of references accurately, and the method can supply theory and application supports for mechanical engineering.

  2. Analysis of volatile organic compounds emitted from aircraft carpets:comparison using headspace and dynamic chamber tests

    Institute of Scientific and Technical Information of China (English)

    WANG Chao; YANG Xu-Dong; GAO Peng


    Volatile organic compounds (VOCs) emitted from three types of carpets used in aircrafts were compared by using headspace and dynamic chamber tests. The headspace samples contained many compounds that were not detected in the dynamic chamber test;in addition, the dominant VOCs found by these two methods were different. The findings indicate that for highly sorptive materials such as carpets, headspace analysis may give inaccurate indication of actual VOC emissions, and it is necessary to conduct dynamic chamber tests over a certain period of time in order to identify the true emission characteristics. From the dynamic chamber tests, 2-ethyl-1-hexanol was the main VOC emitted from all three carpets. The study also examined the emission characteristics of aircraft carpets. In all experiments, total VOC (TVOC) concentration peaked within a few hours after the start of the experiment and was followed by rapid decay. The emission parameters of TVOC emitted by all three carpets were calculated and the simulated data matched the measured data well.

  3. Final Report on Testing of Off-Gas Treatment Technologies for Abatement of Atmospheric Emissions of Chlorinated Volatile Organic Compounds

    Energy Technology Data Exchange (ETDEWEB)

    Jarosch, T.R.; Haselow, J.S.; Rossabi, J.; Burdick, S.A.; Raymond, R.; Young, J.E.; Lombard, K.H.


    The purpose of this report is to summarize the results of the program for off-gas treatment of atmospheric emissions of chlorinated volatile organic compounds (CVOCs), in particular trichloroethylene (TCE) and perchloroethylene (PCE). This program was funded through the Department of Energy Office of Technology Development`s VOC`s in Non-Arid Soils Integrated Demonstration (VNID). The off-gas treatment program was initiated after testing of in-situ air stripping with horizontal wells was completed (Looney et al., 1991). That successful test expectedly produced atmospheric emissions of CVOCs that were unabated. It was decided after that test that an off-gas treatment is an integral portion of remediation of CVOC contamination in groundwater and soil but also because several technologies were being developed across the United States to mitigate CVOC emissions. A single platform for testing off-gas treatment technologies would facilitate cost effective evaluation of the emerging technologies. Another motivation for the program is that many CVOCs will be regulated under the Clean Air Act Amendments of 1990 and are already regulated by many state regulatory programs. Additionally, compounds such as TCE and PCE are pervasive subsurface environmental contaminants, and, as a result, a small improvement in terms of abatement efficiency or cost will significantly reduce CVOC discharges to the environment as well as costs to United States government and industry.

  4. The effects of adulterants and selected ingested compounds on drugs-of-abuse testing in urine. (United States)

    Dasgupta, Amitava


    Household chemicals such as bleach, table salt, laundry detergent, toilet bowl cleaner, vinegar, lemon juice, and eyedrops are used for adulterating urine specimens. Most of these adulterants except eyedrops can be detected by routine specimen integrity tests (creatinine, pH, temperature, and specific gravity); however, certain adulterants such as Klear, Whizzies, Urine Luck, and Stealth cannot. These adulterants can successfully mask drug testing if the concentrations of certain abused drugs are moderate. Several spot tests have been described to detect the presence of such adulterants in urine. Urine dipsticks are commercially available for detecting the presence of such adulterants, along with performance of tests for creatinine, pH, and specific gravity. Certain hair shampoo and saliva-cleaning mouthwashes are available to escape detection in hair or saliva samples, but the effectiveness of such products in masking drugs-of-abuse testing has not been demonstrated. Ingestion of poppy seed cake may result in positive screening test results for opiates, and hemp oil exposure can cause positive results for marijuana. These would be identified as true-positive results in drugs-of-abuse testing even though they do not represent the actual drug of abuse.

  5. On the reactivity of platinum(IV) complexes: Synthesis and spectroscopic studies of platinum(IV) complexes with hypoxanthine (United States)

    Gaballa, Akmal S.


    Na 2[PtCl 6] was found to react with (HypH)Cl·H 2O ( 2) (Hyp=hypoxanthine) in aqueous solution at room temperature yielding (HypH) 2[PtCl 6] ( 3). The same compound was obtained from hexachloroplatinic acid and hypoxanthine. Performing this reaction in methanol at 50 °C complex formation took place yielding the hypoxanthine complex [PtCl 4(Hyp) 2] ( 4). Both compounds were isolated in good yields as faint orange ( 3) and yellow ( 4) precipitates, respectively and characterized by microanalyses, IR and NMR ( 1H, 13C, 195Pt) spectroscopies as well as thermal analysis. Based on the data obtained an octahedral molecular structure is proposed for complex 4 with two hypoxanthine ligands coordinated through N7 to platinum(IV).

  6. Test methods and reduction of organic pollutant compound emissions from wood-based building and furniture materials. (United States)

    Kim, Sumin; Choi, Yoon-Ki; Park, Kyung-Won; Kim, Jeong Tai


    This paper reviews different methods for the analysis of formaldehyde and volatile organic compounds (VOCs) from wood-based panel materials for furniture and building interiors and highlights research on reduction of emission from wood-based panels that can adversely affect indoor air quality. In Korea, standard test methods have been developed to determine formaldehyde and VOC emissions from building products, and the Ministry of Environment regulates the use of building materials with pollutant emissions. Desiccator and perforator methods are being used for formaldehyde and the chamber and field and laboratory emission cell (FLEC) methods for VOC and formaldehyde emissions. The VOC analyzer is a suitable pre-test method for application as a total VOC (TVOC) emission test and bake-out is a useful method to reduce TVOC and formaldehyde emissions from furniture materials in indoor environments.

  7. Optimization and prevalidation of the in vitro ERalpha CALUX method to test estrogenic and antiestrogenic activity of compounds. (United States)

    van der Burg, Bart; Winter, Roos; Weimer, Marc; Berckmans, Pascale; Suzuki, Go; Gijsbers, Linda; Jonas, Arjen; van der Linden, Sander; Witters, Hilda; Aarts, Jac; Legler, Juliette; Kopp-Schneider, Annette; Bremer, Susanne


    Estrogenicity of chemicals has received significant attention and is linked to endocrine-disrupting activities. However, there is a paucity of validated methods to assess estrogenicity in vitro. We have established a robust method to test estrogenic and antiestrogenic activity of compounds in vitro, as an alternative to using animal models such as the uterotrophic assay. To this end we optimized protocols to be used in combination with CALUX reporter gene assays and carried out an in house prevalidation, followed by two rounds of tests to establish transferability. Problems in the initial test with transferability were solved by isolation of a novel cell clone of the ERalpha CALUX line with greatly improved stability and luciferase levels. This cell line proved to be a very suitable and reliable predictor of estrogenicity of chemicals and was able to readily rank a range of chemicals on the basis of their EC50 values.

  8. Toxicity testing of heavy metals with the Rhizobium-legume symbiosis: High sensitivity to cadmium and arsenic compounds. (United States)

    Neumann, H; Bode-Kirchhoff, A; Madeheim, A; Wetzel, A


    Legume root nodules are the site of biological nitrogen fixation in the Rhizobium-legume symbiosis. Nodules are structures unique to this symbiosis and they are morphologically as well as physiologically distinct from other plant organs. Organic substances affecting the macro- or microsymbionts vitality, such as PAHs (WETZEL: et al., 1991), reduce nodulation even before visible damage to the plant can be detected. We present data that the formation of nodules (nodulation) may also serve for ecotoxicological evaluation of heavy metals in different binding states. Tests were performed in petri dishes with alfalfa (lucerne) seedlings inoculated with Rhizobium meliloti. Cultivation took place in growth cabinets with carefully standardized and documented growth conditions. Data from stressed plants was recorded after 14 days of cultivation on contaminated substrate. A dose responsive decrease in nodulation was found after application of cadmium acetate, cadmium iodide, cadmium chloride, sodium salts of arsenate and arsenite, arsenic pentoxide, and lead nitrate, whereas lead acetate showed no effect up to a concentration of 3 microM. The dose response curves were used to calculate EC10, EC50 and EC90 values. EC50 values for cadmium compounds range from 1.5 to 9.5 pM. Testing different arsenic compounds results in EC50 from 2.6 to 20.1 microM. EC50 of lead nitrate is 2.2 microM. The sensitivity, reproducibility and reliability of this test system is discussed compared to established biotests.

  9. Platinum in Earth surface environments (United States)

    Reith, F.; Campbell, S. G.; Ball, A. S.; Pring, A.; Southam, G.


    Platinum (Pt) is a rare precious metal that is a strategic commodity for industries in many countries. The demand for Pt has more than doubled in the last 30 years due to its role in the catalytic conversion of CO, hydrocarbons and NOx in modern automobiles. To explore for new Pt deposits, process ores and deal with ecotoxicological effects of Pt mining and usage, the fundamental processes and pathways of Pt dispersion and re-concentration in surface environments need to be understood. Hence, the aim of this review is to develop a synergistic model for the cycling of Pt in Earth surface environments. This is achieved by integrating the geological/(biogeo)chemical literature, which focuses on naturally occurring Pt mobility around ore deposits, with the environmental/ecotoxicological literature dealing with anthropogenic Pt dispersion. In Pt deposits, Pt occurs as sulfide-, telluride- and arsenide, native metal and alloyed to other PGEs and iron (Fe). Increased mining and utilization of Pt combined with the burning of fossil fuels have led to the dispersion of Pt-containing nano- and micro-particles. Hence, soils and sediments in industrialized areas, urban environments and along major roads are now commonly Pt enriched. Platinum minerals, nuggets and anthropogenic particles are transformed by physical and (bio)geochemical processes. Complexation of Pt ions with chloride, thiosulfate, ammonium, cyanide, low- and high molecular weight organic acids (LMWOAs and HMWOAs) and siderophores can facilitate Pt mobilization. Iron-oxides, clays, organic matter and (micro)biota are known to sequester Pt-complexes and -particles. Microbes and plants are capable of bioaccumulating and reductively precipitating mobile Pt complexes. Bioaccumulation can lead to toxic effects on plants and animals, including humans. (Bio)mineralization in organic matter-rich sediments can lead to the formation of secondary Pt particles and -grains. Ultimately, Pt is enriched in oceanic sediments

  10. Genome-wide fitness test and mechanism-of-action studies of inhibitory compounds in Candida albicans.

    Directory of Open Access Journals (Sweden)

    Deming Xu


    Full Text Available Candida albicans is a prevalent fungal pathogen amongst the immunocompromised population, causing both superficial and life-threatening infections. Since C. albicans is diploid, classical transmission genetics can not be performed to study specific aspects of its biology and pathogenesis. Here, we exploit the diploid status of C. albicans by constructing a library of 2,868 heterozygous deletion mutants and screening this collection using 35 known or novel compounds to survey chemically induced haploinsufficiency in the pathogen. In this reverse genetic assay termed the fitness test, genes related to the mechanism of action of the probe compounds are clearly identified, supporting their functional roles and genetic interactions. In this report, chemical-genetic relationships are provided for multiple FDA-approved antifungal drugs (fluconazole, voriconazole, caspofungin, 5-fluorocytosine, and amphotericin B as well as additional compounds targeting ergosterol, fatty acid and sphingolipid biosynthesis, microtubules, actin, secretion, rRNA processing, translation, glycosylation, and protein folding mechanisms. We also demonstrate how chemically induced haploinsufficiency profiles can be used to identify the mechanism of action of novel antifungal agents, thereby illustrating the potential utility of this approach to antifungal drug discovery.

  11. A novel test method for quantifying surface tack of polypropylene compound surfaces

    Directory of Open Access Journals (Sweden)


    Full Text Available While adhesiveness is required for polymer surfaces in special applications, tacky surfaces are generally undesirable in many applications like automotive interior parts. The tackiness of polymer surface results from a combination of composition and additivation, and it can change significantly in natural or accelerated ageing. Since there is no established, uniform method to characterize surface tack, the major focus of the present work was on the development of an objective quantification method. A setup having a soft die tip attached to a standard tensile tester was developed aiming for correlation to the human sense of touch. Three different model thermoplastic polyolefin (TPO compound formulations based on a high-impact isotactic polypropylene (iPP composition with varying amounts and types of anti-scratch additives were used for these investigations. As the surface tack phenomenon is related to ageing and weathering, the material’s examination was also performed after various intervals of weathering. The developed method allows a fast assessment of the effect of polymer composition variations and different additive formulations on surface tack and gives identical rankings as the standardized haptic panel.

  12. Genotoxicity of a variety of azobenzene and aminoazobenzene compounds in the hepatocyte/DNA repair test and the Salmonella/mutagenicity test. (United States)

    Mori, H; Mori, Y; Sugie, S; Yoshimi, N; Takahashi, M; Ni-i, H; Yamazaki, H; Toyoshi, K; Williams, G M


    Genotoxicity of 39 azo dye compounds of azobenzenes, aminoazobenzenes, and diaminoazobenzenes was examined in the hepatocyte primary culture/DNA repair test. Azobenzene (AzB) and 3,3'- or 4,4'-substituted azobenzenes such as (CH3)2AzB, (CH2OH)2AzB, (CH2OCOCH3)2AzB, and (CH2Cl)2AzB did not generate DNA repair, indicating lack of genotoxicity of these compounds. In contrast, all of 24 aminoazobenzenes, including those of unknown carcinogenicity, i.e., 3'-methyl-4-aminoazobenzene, 3'-CH2OH-aminoazobenzene, 3'-hydroxymethyl-N-methyl-4-aminoazobenzene, 3'-COOH-methylaminoazobenzene, 4'-formyl-N,N-dimethyl-4-aminoazobenzene, 3'-CH2Cl-dimethylaminoazobenzene, 4'-CH2Cl-dimethylaminoazobenzene, and 2'-, 3'-, or 4'-CH2OCOCH3-dimethylaminoazobenzene, elicited DNA repair synthesis. A positive DNA repair response was obtained for the 3 of 6 tested diaminoazobenzenes, i.e., N'-acetyl-N'-methyl-4-amino-dimethylaminoazobenzene, N'-acetyl-N'-methyl-4-amino-methylaminoazobenzene, and N'-acetyl-N'-methyl-4-amino-N-acetyl-methylaminoazobenzene, which are known to be carcinogenic. These results indicate that the amino group is functional for the expression of genotoxicity of azobenzene compounds. Twenty-one azobenzenes of these 3 classes were also examined for their mutagenicity in the Salmonella/mutagenicity assay. These results were almost identical with those of the DNA repair test except for several azo dyes such as AzB and 4,4'-(CH2Oacetyl)2AzB of the azobenzenes and N'-acetyl-4-amino-dimethylaminoazobenzene and N'-acetyl-N-methyl-4-amino-N-acetyl methylaminoazobenzene of the diaminoazobenzenes.

  13. Acoustic emission analysis as a non-destructive test procedure for fiber compound structures (United States)

    Block, J.


    The concept of acoustic emission analysis is explained in scientific terms. The detection of acoustic events, their localization, damage discrimination, and event summation curves are discussed. A block diagram of the concept of damage-free testing of fiber-reinforced synthetic materials is depicted. Prospects for application of the concept are assessed.

  14. Development and application of long-term sublethal whole sediment tests with Arenicola marina and Corophium volutator using Ivermectin as the test compound

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Yvonne T. [Centre for Environment, Fisheries and Aquaculture Science, Burnham Laboratory, Remembrance Avenue, Burnham-on-Crouch, Essex, CM0 8HA (United Kingdom)]. E-mail:; Thain, John E. [Centre for Environment, Fisheries and Aquaculture Science, Burnham Laboratory, Remembrance Avenue, Burnham-on-Crouch, Essex, CM0 8HA (United Kingdom); Haworth, Sarah [Centre for Environment, Fisheries and Aquaculture Science, Burnham Laboratory, Remembrance Avenue, Burnham-on-Crouch, Essex, CM0 8HA (United Kingdom); Barry, Jon [Centre for Environment, Fisheries and Aquaculture Science, Burnham Laboratory, Remembrance Avenue, Burnham-on-Crouch, Essex, CM0 8HA (United Kingdom)


    Short-term whole sediment tests using the amphipod Corophium volutator and the polychaete Arenicola marina are now routinely used in Europe to assess the acute toxicity of marine sediments. However, there is still a need to develop longer-term assays which measure effects on sublethal endpoints that are more relevant to predicting impacts at the population level. The effect of increasing exposure times and measuring additional endpoints such as growth, on the sensitivity of these assays was investigated. The test compound used was the chemotherapeutant Ivermectin (IVM), used in aquaculture to treat sea lice infestations. IVM was found to be acutely toxic to both test organisms. Extending the lugworm test to 100 days increased sensitivity of survival by a factor of three; a significant reduction in casting rate was observed at concentrations an order of magnitude lower. This assay shows potential for detecting the sublethal effects of low concentrations of sediment contaminants. Increasing the exposure time did not seem to affect the sensitivity of the amphipod, but further method development is required. - Long-term sublethal sediment tests are more sensitive than standard acute tests when assessing the toxic effects of Ivermectin.

  15. Reproducing the organic matter model of anthropogenic dark earth of Amazonia and testing the ecotoxicity of functionalized charcoal compounds

    Directory of Open Access Journals (Sweden)

    Carolina Rodrigues Linhares


    Full Text Available The objective of this work was to obtain organic compounds similar to the ones found in the organic matter of anthropogenic dark earth of Amazonia (ADE using a chemical functionalization procedure on activated charcoal, as well as to determine their ecotoxicity. Based on the study of the organic matter from ADE, an organic model was proposed and an attempt to reproduce it was described. Activated charcoal was oxidized with the use of sodium hypochlorite at different concentrations. Nuclear magnetic resonance was performed to verify if the spectra of the obtained products were similar to the ones of humic acids from ADE. The similarity between spectra indicated that the obtained products were polycondensed aromatic structures with carboxyl groups: a soil amendment that can contribute to soil fertility and to its sustainable use. An ecotoxicological test with Daphnia similis was performed on the more soluble fraction (fulvic acids of the produced soil amendment. Aryl chloride was formed during the synthesis of the organic compounds from activated charcoal functionalization and partially removed through a purification process. However, it is probable that some aryl chloride remained in the final product, since the ecotoxicological test indicated that the chemical functionalized soil amendment is moderately toxic.

  16. Standard test method for determination of impurities in nuclear grade uranium compounds by inductively coupled plasma mass spectrometry

    CERN Document Server

    American Society for Testing and Materials. Philadelphia


    1.1 This test method covers the determination of 67 elements in uranium dioxide samples and nuclear grade uranium compounds and solutions without matrix separation by inductively coupled plasma mass spectrometry (ICP-MS). The elements are listed in Table 1. These elements can also be determined in uranyl nitrate hexahydrate (UNH), uranium hexafluoride (UF6), triuranium octoxide (U3O8) and uranium trioxide (UO3) if these compounds are treated and converted to the same uranium concentration solution. 1.2 The elements boron, sodium, silicon, phosphorus, potassium, calcium and iron can be determined using different techniques. The analyst's instrumentation will determine which procedure is chosen for the analysis. 1.3 The test method for technetium-99 is given in Annex A1. 1.4 The values stated in SI units are to be regarded as standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish ...

  17. Chemical Imaging of Platinum-Based Drugs and their Metabolites. (United States)

    Liu, Xin; Hummon, Amanda B


    Platinum-based drugs (cisplatin, carboplatin, and oxaliplatin) are widely used therapeutic agents for cancer treatment. Even though the platinum (Pt)-drugs are routinely used clinically, a clear picture of their distribution within tumor tissues is lacking. The current methods to image the distribution of Pt drugs are limited and do not enable the discrimination of the drug from its metabolites. In this manuscript, we demonstrate a methodology that enables chemical imaging of a Pt drug and its metabolites simultaneously and specifically. Matrix-Assisted Laser Desorption/Ionization (MALDI) Mass Spectrometry Imaging (MSI) is combined with an on-tissue chemical derivatization using diethyldithiocarbamate (DDTC). DDTC abstracts the Pt atom to generate ionizable complexes that can be imaged by MALDI MSI. We demonstrate that Pt drugs and their metabolites can be specifically imaged. This approach was successfully applied to map the penetration and metabolism of oxaliplatin in hyperthermic intraperitoneal chemotherapy (HIPEC)-like treated 3D colorectal tumor mimics. The distribution of cisplatin and carboplatin was mapped in additional 3D tumor mimics. We demonstrate that the approach can also be used to image the distribution of copper ions in cells. This method has the potential to be used to evaluate the penetration and distribution of a wide range of compounds.

  18. Sulfur tolerant zeolite supported platinum catalysts for aromatics hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Bergem, Haakon


    The increased demand for transportation fuels at the expence of heavier fuel oil has forced the refinery industry to expand their conversion capacity with hydrotreating as one of the key processes. A shift towards more diesel powered vehicles along with tightening fuel regulations demanding cleaner fuels has lead to increasing interest in catalytic processes for the manufacturing of such environmentally acceptable fuels. This provides the motivation for this thesis. Its main objective was to study possible catalysts active for desulfurization, hydrogenation, and ring-opening of aromatics all in the presence of sulfur. A close examination of the physical properties and kinetical behaviour of the chosen catalysts has been performed. A high pressure reactor setup was designed and built for activity measurements. Zeolite supported platinum catalysts were prepared and both the metal and acid functions were characterized utilizing various experimental techniques. Hydrogenation of toluene was used as a model reaction and the effect of sulfur adsorption on the activity and kinetic behaviour of the catalysts was investigated. The catalyst samples showed hydrogenation activities comparable to a commercial Pt/Al2O3 catalyst. There were no clear differences in the effect of the various sulfur compounds studied. Platinum supported on zeolite Y gave considerably more sulfur tolerant catalysts compared to Al2O3 as support. 155 refs., 58 figs., 36 tabs.

  19. A category approach to predicting the developmental (neuro) toxicity of organotin compounds: The value of the zebrafish (Danio rerio) embryotoxicity test (ZET)

    NARCIS (Netherlands)

    Beker van Woudenberg, A.; Wolterbeek, A.; Brake, L. te; Snel, C.; Menke, A.; Rubingh, C.; Groot, D. de; Kroese, D.


    Zebrafish embryos were exposed to different organotin compounds during very early development (<100. h post fertilization). Morphology, histopathology and swimming activity (in a motor activity test) were the endpoints analyzed. DBTC was, by far, the most embryotoxic compound at all time points and

  20. computer modeling ter modeling ter modeling of platinum reforming ...

    African Journals Online (AJOL)


    naphtha to complex chemical reactions, at h temperature and ... at is leaving any stage of the platinum reforming reactors in terms of ... In this study, only platinum reforming .... IV. Hydrocracking of paraffinic hydrocarbons: +. →. ( +. +. +. +. ) (18).

  1. Novel platinum black electroplating technique improving mechanical stability. (United States)

    Kim, Raeyoung; Nam, Yoonkey


    Platinum black microelectrodes are widely used as an effective neural signal recording sensor. The simple fabrication process, high quality signal recording and proper biocompatibility are the main advantages of platinum black microelectrodes. When microelectrodes are exposed to actual biological system, various physical stimuli are applied. However, the porous structure of platinum black is vulnerable to external stimuli and destroyed easily. The impedance level of the microelectrode increases when the microelectrodes are damaged resulting in decreased recording performance. In this study, we developed mechanically stable platinum black microelectrodes by adding polydopamine. The polydopamine layer was added between the platinum black structures by electrodeposition method. The initial impedance level of platinum black only microelectrodes and polydopamine added microelectrodes were similar but after applying ultrasonication the impedance value dramatically increased for platinum black only microelectrodes, whereas polydopamine added microelectrodes showed little increase which were nearly retained initial values. Polydopamine added platinum black microelectrodes are expected to extend the availability as neural sensors.

  2. Trastuzumab-mediated selective delivery for platinum drug to HER2-positive breast cancer cells. (United States)

    Huang, Rong; Sun, Yu; Gao, Qihe; Wang, Qiucui; Sun, Baiwang


    Oxaliplatin is used widely as an anticancer drug for clinical treatment. However, its applications are limited because of its poor selectivity. In this work, we described the design, synthesis, and characterization of conjugates combining trastuzumab with a platinum (IV) analog of oxaliplatin, in which the trastuzumab acted as an active targeting agent for HER2-positive cancer cells. Indirect enzyme-linked immunosorbent assay and immunofluorescence study indicated the platinum (IV)-trastuzumab conjugates retained specific binding activity to HER2 overexpressed SK-BR-3 cells. In the presence of ascorbic acid, platinum (IV)-trastuzumab conjugates were reduced to platinum (II) analogs, which could bind to and unwind PUC19 DNA in a manner similar to oxaliplatin. The cytotoxic study was tested on three breast cell lines: SK-BR-3, MCF-7, and MDA-MB-231. Platinum (IV)-trastuzumab conjugates showed promising antiproliferative activity against SK-BR-3 cells, but significantly decreased the inhibition to MDA-MB-231 and MCF-7 cells. The flow cytometric analysis showed that the conjugates arrested the cell cycle mainly at the G2/M phase and killed the cells through an apoptotic pathway.

  3. Microstructural Study on Oxidation Resistance of Nonmodified and Platinum Modified Aluminide Coating (United States)

    Zagula-Yavorska, Maryana; Sieniawski, Jan


    Platinum electroplating layers (3 and 7 μm thick) were deposited on the surface of the Inconel 713 LC, CMSX 4, and Inconel 625 Ni-base superalloys. Diffusion treatment at 1050°C for 2 h under argon atmosphere was performed after electroplating. Diffusion treated samples were aluminized according to the low activity CVD process at 1050°C for 8 h. The nonmodified aluminide coatings consist of NiAl phase. Platinum modification let to obtain the (Ni,Pt)Al phase in coatings. The coated samples were subjected to cyclic oxidation testing at 1100°C. It was discovered that increase of the platinum electroplating thickness from 3 to 7 μm provides the improvement of oxidation resistance of aluminide coatings. Increase of the platinum thickness causes decreases in weight change and decreases in parabolic constant during oxidation. The platinum provides the pure Al2O3 oxide formation, slow growth oxide layer, and delay the oxide spalling during heating-cooling thermal cycles.

  4. Platinum uptake from chloride solutions using biosorbents

    Directory of Open Access Journals (Sweden)

    Mehmet Hakan Morcali


    Full Text Available Present work investigates platinum uptake from synthetically prepared, dilute platinum-bearing solutions using biomass residues, i.e. pistachio nut shell and rice husk, which are abundant in Turkey, and provides a comparison between these two biosorbents. Effects of the different uptake parameters, sorbent dosage, contact time, temperature and pH of solution on platinum uptake (% were studied in detail on a batch sorption. Before the pistachio nut shell was activated, platinum uptake (% was poor compared to the rice husk. However, after the pistachio nut shell was activated at 1000 °C under an argon atmosphere, the platinum uptake (% increased two-fold. The pistachio nut shell (original and activated and rice husk were shown to be better than commercially available activated carbon in terms of adsorption capacity. These two sorbents have also been characterized by FTIR and SEM. Adsorption equilibrium data best complied with the Langmuir isotherm model. Maximum adsorption capacities, Qmax, at 25 °C were found to be 38.31 and 42.02 mg.g- 1for the activated pistachio nut shell and rice husk, respectively. Thermodynamic calculations using the measured ∆H°, ∆S° and ∆G° values indicate that the uptake process was spontaneous and endothermic. The experimental data were shown to be fit the pseudo-second-order kinetic model.

  5. Novel Approaches for Concurrent Irradiation in Locally Advanced Cervical Cancer: Platinum Combinations, Non-Platinum-Containing Regimens, and Molecular Targeted Agents

    Directory of Open Access Journals (Sweden)

    Giannis Mountzios


    Full Text Available Despite the available prevention and early detection strategies, squamous-cell carcinoma of the uterine cervix is still diagnosed as locally advanced disease in a considerable proportion of patients. As a potent sensitizer of cancer cells, cisplatin has been the “traditional partner” of external beam irradiation in this setting for more than two decades. Induction chemotherapy strategies followed by concurrent chemoradiation or surgery and preoperative concurrent chemoradiation have been recently implemented in clinical trials in an effort to optimize local control and to minimize the risk of distant metastases. In this context, cisplatin has been combined with a number of other potential radiosensitizers, including 5-fluorouracil, capecitabine, and gemcitabine. In patients resistant or intolerant to platinum compounds, numerous non-platinum-containing regimens have been developed, implementing various antimetabolites, taxanes, antineoplastic antibiotics, and topoisomerase II inhibitors. More recently, molecular agents targeting critical pathways in cervical malignant transformation are being assessed in early clinical trials in combination with external-beam irradiation. In the current work, we review the evolving role of cisplatin and other platinum compounds, either alone or in combination regimens, in the context of other potent radiosensitizers. The emerging role of molecular targeted agents, as candidate partners of external beam irradiation, is also discussed.

  6. Cytotoxic properties of a new organometallic platinum(II) complex and its gold(I) heterobimetallic derivatives. (United States)

    Serratrice, Maria; Maiore, Laura; Zucca, Antonio; Stoccoro, Sergio; Landini, Ida; Mini, Enrico; Massai, Lara; Ferraro, Giarita; Merlino, Antonello; Messori, Luigi; Cinellu, Maria Agostina


    A novel platinum(ii) organometallic complex, [Pt(pbi)(Me)(DMSO)], bearing the 2-(2'-pyridyl)-benzimidazole (pbiH) ligand, was synthesized and fully characterized. Interestingly, the reaction of this organometallic platinum(ii) complex with two distinct gold(i) phosphane compounds afforded the corresponding heterobimetallic derivatives with the pbi ligand bridging the two metal centers. The antiproliferative properties in vitro of [Pt(pbi)(Me)(DMSO)] and its gold(i) derivatives as well as those of the known coordination platinum(ii) and palladium(ii) complexes with the same ligand, of the general formula [MCl2(pbiH)], were comparatively evaluated against A2780 cancer cells, either sensitive or resistant to cisplatin. A superior biological activity of the organometallic compound clearly emerged compared to the corresponding platinum(ii) complex; the antiproliferative effects are further enhanced upon attaching the gold(i) triphenylphosphine moiety to the organometallic Pt compound. Remarkably, these novel metal species are able to overcome nearly complete resistance to cisplatin. Significant mechanistic insight into the study compounds was gained after investigating their reactions with a few representative biomolecules by electrospray mass spectrometry and X-ray crystallography. The obtained results are comprehensively discussed.

  7. Electrochemical Fabrication and Electrocatalytic Properties of Nanostructured Mesoporous Platinum Microelectrodes

    Institute of Scientific and Technical Information of China (English)

    Mengyan NIE; Joanne M. Elliott


    Electrodeposition from a lyotropic liquid crystal template medium was used to produce nanostructured platinum microelectrodes with high specific surface area and high mass transport efficiency. Compared to polished and conventional platinized microelectrodes, well-ordered nanostructured platinum microelectrodes exhibited enhanced electrocatalytic properties for oxygen and ascorbic acid, whilst well-ordered nanostructured platinum microelectrodes offered improved electrocatalytic properties for oxygen reduction compared to disordered nanostructured platinum microelectrodes.

  8. [Use of phenylglyoxylic ketyl radicals in testing for antioxidative effects of various compounds]. (United States)

    Sersen, F; Vencel, T; Gáplovský, A; Anus, T


    The paper describes spontaneous decomposition of D,L-2,3-diphenyltartaric acid in propane-2-ol, which takes place via radicals at ambient temperature. The primary product of the decomposition is short-living ketyl radicals of phenylglyoxalic acid, which are captured and stabilized by means of the spin trap of N-terc-butyl-alpha-phenylnitrone. The spontaneous decomposition of D,L-2,3-diphenyltartaric acid in propane-2-ol served as the source of radicals for the determination of the antioxidative effect of known antioxidants: C-vitamin, E-vitamin, and selenomethionine. It was found that the above-mentioned antioxidants are effective scavengers of radicals of phenylglyoxalic acid. On the basis of these data, the method can be recommended for testing the antioxidative properties of other substances as potential antioxidants.

  9. Developing strongly luminescent platinum(IV) complexes: facile synthesis of bis-cyclometalated neutral emitters. (United States)

    Juliá, Fabio; Bautista, Delia; González-Herrero, Pablo


    A straightforward, one-pot procedure has been developed for the synthesis of bis-cyclometalated chloro(methyl)platinum(IV) complexes with a wide variety of heteroaromatic ligands of the 2-arylpyridine type. The new compounds exhibit phosphorescent emissions in the blue to orange colour range and represent the most efficient Pt(IV) emitters reported to date, with quantum yields up to 0.81 in fluid solutions at room temperature.

  10. Extensions of Callendar's equations for platinum resistance thermometry

    DEFF Research Database (Denmark)

    Diamond, Joseph M.


    measurements where the platinum thermometer and the measurement means may be less than ideal. To this end. Callendar's definition of platinum temperature is generalized to mean the temperature found by linear interpolation with a platinum thermometer between given fixed points and using a given measurement...

  11. Platinum Publications as of April 30, 2014 | Poster (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  12. Platinum Publications, September 30–October 27, 2016 | Poster (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  13. Platinum Publications as of June 25, 2014 | Poster (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  14. Platinum Publications, July 1–July 28, 2016 | Poster (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  15. Platinum Publications as of March 6, 2014 | Poster (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  16. Platinum Publications, October 1–29, 2015 | Poster (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  17. Platinum Publications, December 1–December 29, 2016 | Poster (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected from among the most recently published Platinum Publications.

  18. Platinum Publications as of May 29, 2014 | Poster (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  19. Platinum Publications as of September 25, 2014 | Poster (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  20. Platinum Publications, January 26–February 28, 2017 | Poster (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected from among the most recently published Platinum Publications.

  1. Platinum Publications as of December 3, 2013 | Poster (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 21 prestigious science journals. This list represents new publications generated from PubMed as of the date shown above. Articles designated as Platinum Highlights are noteworthy articles selected by Dr. Craig Reynolds, associate director, National Cancer Institute, from among the most recently published Platinum Publications.

  2. Deposition of the platinum crystals on the carbon nanotubes

    Institute of Scientific and Technical Information of China (English)


    A new technique and the affecting factors for depositing platinum on the carbon nanotubes were investigated. The results show that the deposited platinum crystals in the atmosphere of hydrogen or nitrogen have a small size and a homogeneous distribution on the surface of the carbon nanotubes. The pretreatment would decrease the platinum particles on the carbon nanotubes significantly.

  3. 76 FR 8627 - Revision of Class E Airspace; Platinum, AK (United States)


    ... Federal Aviation Administration 14 CFR Part 71 Revision of Class E Airspace; Platinum, AK AGENCY: Federal... Platinum, AK, to accommodate the addition of a Standard Instrument Approach Procedure (SIAP), at the Platinum Airport. The FAA is taking this action to enhance safety and management of Instrument Flight...

  4. Surface decorated platinum carbonyl clusters (United States)

    Ciabatti, Iacopo; Femoni, Cristina; Iapalucci, Maria Carmela; Longoni, Giuliano; Zacchini, Stefano; Zarra, Salvatore


    Four molecular Pt-carbonyl clusters decorated by Cd-Br fragments, i.e., [Pt13(CO)12{Cd5(μ-Br)5Br2(dmf)3}2]2- (1), [Pt19(CO)17{Cd5(μ-Br)5Br3(Me2CO)2}{Cd5(μ-Br)5Br(Me2CO)4}]2- (2), [H2Pt26(CO)20(CdBr)12]8- (3) and [H4Pt26(CO)20(CdBr)12(PtBr)x]6- (4) (x = 0-2), have been obtained from the reactions between [Pt3n(CO)6n]2- (n = 2-6) and CdBr2.H2O in dmf at 120 °C. The structures of these molecular clusters with diameters of 1.5-2 nm have been determined by X-ray crystallography. Both 1 and 2 are composed of icosahedral or bis-icosahedral Pt-CO cores decorated on the surface by Cd-Br motifs, whereas 3 and 4 display a cubic close packed Pt26Cd12 metal frame decorated by CO and Br ligands. An oversimplified and unifying approach to interpret the electron count of these surface decorated platinum carbonyl clusters is suggested, and extended to other low-valent organometallic clusters and Au-thiolate nanoclusters.Four molecular Pt-carbonyl clusters decorated by Cd-Br fragments, i.e., [Pt13(CO)12{Cd5(μ-Br)5Br2(dmf)3}2]2- (1), [Pt19(CO)17{Cd5(μ-Br)5Br3(Me2CO)2}{Cd5(μ-Br)5Br(Me2CO)4}]2- (2), [H2Pt26(CO)20(CdBr)12]8- (3) and [H4Pt26(CO)20(CdBr)12(PtBr)x]6- (4) (x = 0-2), have been obtained from the reactions between [Pt3n(CO)6n]2- (n = 2-6) and CdBr2.H2O in dmf at 120 °C. The structures of these molecular clusters with diameters of 1.5-2 nm have been determined by X-ray crystallography. Both 1 and 2 are composed of icosahedral or bis-icosahedral Pt-CO cores decorated on the surface by Cd-Br motifs, whereas 3 and 4 display a cubic close packed Pt26Cd12 metal frame decorated by CO and Br ligands. An oversimplified and unifying approach to interpret the electron count of these surface decorated platinum carbonyl clusters is suggested, and extended to other low-valent organometallic clusters and Au-thiolate nanoclusters. CCDC 867747 and 867748. For crystallographic data in CIF or other electronic format see DOI: 10.1039/c2nr30400g

  5. Autonomous movement of platinum-loaded stomatocytes. (United States)

    Wilson, Daniela A; Nolte, Roeland J M; van Hest, Jan C M


    Polymer stomatocytes are bowl-shaped structures of nanosize dimensions formed by the controlled deformation of polymer vesicles. The stable nanocavity and strict control of the opening are ideal for the physical entrapment of nanoparticles which, when catalytically active, can turn the stomatocyte morphology into a nanoreactor. Herein we report an approach to generate autonomous movement of the polymer stomatocytes by selectively entrapping catalytically active platinum nanoparticles within their nanocavities and subsequently using catalysis as a driving force for movement. Hydrogen peroxide is free to access the inner stomatocyte cavity, where it is decomposed by the active catalyst (the entrapped platinum nanoparticles) into oxygen and water. This generates a rapid discharge, which induces thrust and directional movement. The design of the platinum-loaded stomatocytes resembles a miniature monopropellant rocket engine, in which the controlled opening of the stomatocytes directs the expulsion of the decomposition products away from the reaction chamber (inner stomatocyte cavity).

  6. Establishment of alternative potency test for botulinum toxin type A using compound muscle action potential (CMAP) in rats. (United States)

    Torii, Yasushi; Goto, Yoshitaka; Nakahira, Shinji; Ginnaga, Akihiro


    The biological activity of botulinum toxin type A has been evaluated using the mouse intraperitoneal (ip) LD50 test. This method requires a large number of mice to precisely determine toxin activity, and, as such, poses problems with regard to animal welfare. We previously developed a compound muscle action potential (CMAP) assay using rats as an alternative method to the mouse ip LD50 test. In this study, to evaluate this quantitative method of measuring toxin activity using CMAP, we assessed the parameters necessary for quantitative tests according to ICH Q2 (R1). This assay could be used to evaluate the activity of the toxin, even when inactive toxin was mixed with the sample. To reduce the number of animals needed, this assay was set to measure two samples per animal. Linearity was detected over a range of 0.1-12.8 U/mL, and the measurement range was set at 0.4-6.4 U/mL. The results for accuracy and precision showed low variability. The body weight was selected as a variable factor, but it showed no effect on the CMAP amplitude. In this study, potency tests using the rat CMAP assay of botulinum toxin type A demonstrated that it met the criteria for a quantitative analysis method.

  7. Vapour Treatment Method Against Other Pyro- and Hydrometallurgical Processes Applied to Recover Platinum From Used Auto Catalytic Converters

    Institute of Scientific and Technical Information of China (English)

    Agnieszka FORNALCZYK; Mariola SATERNUS


    Today more and more cars are produced every year.All of them have to be equipped with catalytic converters,the main role of which is to obtain substances harmless to the environment instead of exhausted gases.Catalytic converters contain platinum group metals (PGM) especially platinum,palladium and rhodium.The price of these metals and their increasing demand are the reasons why today it is necessary to recycle used auto catalytic converters.There are many available methods of recovering PGM metals from them,especially platinum.These methods used mainly hydrometallurgical processes; however pyrometallurgical ones become more and more popular.The article presents results of the research mainly concerning pyrometallurgical processes.Two groups of research were carried out.In the first one different metals such as lead,magnesium and copper were used as a metal collector.During the tests,platinum went to those metals forming an alloy.In other research metal vapours were blown through catalytic converter carrier (grinded or whole).In the tests metals such as calcium,magnesium,cadmium and zinc were applied.As a result white or grey powder (metal plus platinum) was obtained.The tables present results of the research.Processing parameters and conclusions are also shown.To compare efficiency of pyrometallurgical and hydrometallurgical methods catalytic converter carrier and samples of copper with platinum obtained from pyrometallurgical method were solved in aqua regia,mixture of aqua regia and fluoric acid.

  8. Evaluation of ozone generation and indoor organic compounds removal by air cleaners based on chamber tests (United States)

    Yu, Kuo-Pin; Lee, Grace Whei-May; Hsieh, Ching-Pei; Lin, Chi-Chi


    Ozone can cause many health problems, including exacerbation of asthma, throat irritation, cough, chest ache, shortness of breath, and respiratory infections. Air cleaners are one of the sources of indoor ozone, and thus the evaluation of ozone generated by air cleaners is desired significant issue. Most evaluation methods proposed are based on chamber tests. However, the adsorption and desorption of ozone on the wall of test chamber and the deposition of ozone resulted from the surface reaction can influence the evaluation results. In this study, we developed a mass balance model that took the adsorption, desorption and deposition of ozone into consideration to evaluate the effective ozone emission rates of six selected air cleaners. The experiments were conducted in a stainless steel chamber with a volume of 11.3 m 3 at 25 °C and 60% relative humidity. The adsorption, desorption and deposition rate constants of ozone obtained by fitting the model to the experimental data were k a = 0.149 ± 0.052 m h -1, k d = 0.013 ± 0.007 h -1, and k r = 0.050 ± 0.020 h -1, respectively. The effective ozone emission rates of Air Cleaners No. 1, 2, and 3 ranged between 13,400-24,500 μg h -1, 7190-10,400 μg h -1, and 4880-6560 μg h -1, respectively, which were more stable than those of No.4, 5, and 6. The effective ozone emission rates of Air Cleaners No. 4, 5, and 6 increased with the time of operation which might be relevant to the decrease of ozone removal by the "aging" filter installed in these cleaners. The removal of toluene and formaldehyde by these six air cleaners were also evaluated and the clean air delivery rates (CADRs) of these two pollutants ranged from non-detectable to 0.42 ± 0.08 m 3 h -1, and from non-detectable to 0.75 ± 0.07 m 3 h -1, respectively. The CADRs showed an insignificant relationship with the effective ozone emission rates. Thus, the removal of toluene and formaldehyde might be resulted from the adsorption on the filters and the

  9. 2-Methoxycycloocta-1,5-dienyl platinum complexes as precursors for platinum nanoparticles

    Indian Academy of Sciences (India)

    Ninad Ghavale; Sandip Dey; Vimal K Jain; R Tewari


    Thermolysis of [Pt2 (-OR)2 (C8H12OMe)2] (R = Me or Ac) in hexadecylamine (HDA) at 210°C under argon atmosphere gave platinum nanoparticles which were characterized by XRD, EDAX and TEM analysis. Both spherical (∼ 10 nm) and rod-like (∼ 19 nm length with aspect ratio of 2.3) face centred cubic (fcc) platinum metal nanoparticles could be isolated. The thermogravimetric analyses of these complexes revealed that they undergo a single step decomposition leading to the formation of platinum metal powder.

  10. Biodegradation of wastewater nitrogen compounds in fractures: Laboratory tests and field observations (United States)

    Masciopinto, Constantino


    Throughout several coastal regions in the Mediterranean where rainfalls rarely exceed 650 mm per year municipal treated wastewater can be conveniently reused for soil irrigation. Where the coastal aquifer supplies large populations with freshwater in such area, an assessment of ground water quality around spreading sites is needed. In this study, the efficacy of natural filtration on nitrogen degradation in wastewater spreads on the soil covering the Salento (Southern Italy) fractured limestone was quantified by using laboratory tests and field measurements. In the laboratory, effluent from municipal wastewater treatment plants was filtered through a package of fractures made by several slabs of limestone. An analysis of wastewater constituent concentrations over time allowed the decay rates and constants for nitrogen transformation during natural filtration to be estimated in both aerated and non-aerated (i.e., saturated) soil fractures. A simulation code, based on biodegradation decay constants defined in the laboratory experiments, was then used to quantify the total inorganic nitrogen removal from wastewater injected in an aquifer in the Salento region (Nardò). Here the water sampled in two monitoring wells at 320 m and 500 m from the wastewater injection site and downgradient with respect to groundwater flow was used to verify the laboratory nitrification and denitrification rates.

  11. 2-Deoxyglucose conjugated platinum (II) complexes for targeted therapy: design, synthesis, and antitumor activity. (United States)

    Mi, Qian; Ma, Yuru; Gao, Xiangqian; Liu, Ran; Liu, Pengxing; Mi, Yi; Fu, Xuegang; Gao, Qingzhi


    Malignant neoplasms exhibit an elevated rate of glycolysis over normal cells. To target the Warburg effect, we designed a new series of 2-deoxyglucose (2-DG) conjugated platinum (II) complexes for glucose transporter 1 (GLUT1)-mediated anticancer drug delivery. The potential GLUT1 transportability of the complexes was investigated through a comparative molecular docking analysis utilizing the latest GLUT1 protein crystal structure. The key binding site for 2-DG as GLUT1's substrate was identified with molecular dynamics simulation, and the docking study demonstrated that the 2-DG conjugated platinum (II) complexes can be recognized by the same binding site as potential GLUT1 substrate. The conjugates were synthesized and evaluated for in vitro cytotoxicity study with seven human cancer cell lines. The results of this study revealed that 2-DG conjugated platinum (II) complexes are GLUT1 transportable substrates and exhibit improved cytotoxicities in cancer cell lines that over express GLUT1 when compared to the clinical drug, Oxaliplatin. The correlation between GLUT1 expression and antitumor effects are also confirmed. The study provides fundamental information supporting the potential of the 2-DG conjugated platinum (II) complexes as lead compounds for further pharmaceutical R&D.

  12. Semiquantitative determination of some nitrogen compounds by the formation of charge-transfer complexes of diphenylamine with p-dimethylaminobenzaldehyde by capillary solid-state spot-tests

    Institute of Scientific and Technical Information of China (English)

    Ishaat; M.Khan


    The interactions of p-dimethylaminobenzaldehyde (p-DAB) and potassium hydrogen sulphate (PHS) in equimolar ratio with various concentration of diphenylamine (solid test material) have been investigated by capillary spot-tests technique in order to investigate the effect of temperature and volume of material in test-tube. The formation of the colored boundary in the capillary is taken for the detection of organic compounds by spot-tests at different temperature and volume of solid test material.

  13. Development and application of long-term sublethal whole sediment tests with Arenicola marina and Corophium volutator using Ivermectin as the test compound. (United States)

    Allen, Yvonne T; Thain, John E; Haworth, Sarah; Barry, Jon


    Short-term whole sediment tests using the amphipod Corophium volutator and the polychaete Arenicola marina are now routinely used in Europe to assess the acute toxicity of marine sediments. However, there is still a need to develop longer-term assays which measure effects on sublethal endpoints that are more relevant to predicting impacts at the population level. The effect of increasing exposure times and measuring additional endpoints such as growth, on the sensitivity of these assays was investigated. The test compound used was the chemotherapeutant Ivermectin (IVM), used in aquaculture to treat sea lice infestations. IVM was found to be acutely toxic to both test organisms. Extending the lugworm test to 100 days increased sensitivity of survival by a factor of three; a significant reduction in casting rate was observed at concentrations an order of magnitude lower. This assay shows potential for detecting the sublethal effects of low concentrations of sediment contaminants. Increasing the exposure time did not seem to affect the sensitivity of the amphipod, but further method development is required.

  14. Photolysis of an arylalkyl-triazenido-platinum-IV complex (United States)

    Lippert, T.; Dauth, J.; Deubzer, B.; Weis, J.; Wokaun, A.


    The photolytic decomposition of tetrakis(1-phenyl-3-hexyl-triazenido)-platinum(IV) is studied in a variety of media, and found to proceed according to simple first order kinetics. Two excimer laser wavelengths, an excimer-laser pumped dye laser, and a broadband mercury lamp are used for excitation. As referred to the incident power, selective irradiation near the complex-specific absorption maximum is found to be most efficient for inducing the photolytic decomposition. A different influence of degassing and oxygen saturation is observed for tetrahydrofurane and for technical siloxane solvents. To elucidate the origins of the observed behaviour, decomposition products of the complex, and products of hydrosilylation reactions catalyzed by this compound, are identified by GC/MS analysis.

  15. Approach to develop a standardized TLC-DPPH• test for assessing free radical scavenging properties of selected phenolic compounds. (United States)

    Cieśla, Łukasz; Kryszeń, Jakub; Stochmal, Anna; Oleszek, Wiesław; Waksmundzka-Hajnos, Monika


    TLC-DPPH(•) test belongs to a group of frequently performed assays aimed at detection of compounds with desired activity (effect directed analysis). Despite its popularity a standard procedure has not been elaborated so far causing difficulties in comparing results obtained in different laboratories. Thus the aim of the presented research was an approach to develop a standardized procedure for assessing free radical scavenging properties of plant polyphenols. It was observed that specifically positive adsorbent (silica gel) strengthened the observed result of radical-antioxidant reaction, while polar bonded stationary phase CN-silica weakened it. Based on the observed results it was concluded that the TLC-DPPH(•) assay should be preferably performed on the surface of non-specific adsorbents (e.g.: RP-18) with the use of n-hexane for DPPH(•) dissolution. It is also proposed to document the results every 5 min after staining, as they change in time.

  16. Optimization of the route of platinum drugs administration to optimize the concomitant treatment with radiotherapy for glioblastoma implanted in the Fischer rat brain (United States)

    Charest, Gabriel; Sanche, Léon; Fortin, David; Mathieu, David; Paquette, Benoit


    Treatment of glioblastoma with platinum compounds modestly improves progression-free survival and may cause toxic effects which prevent use at higher dose that would otherwise improve the antineoplastic effect. To reduce toxicity, we propose to encapsulate the platinum drug in a liposome. We have also tested three methods of drug administration (intra-venous, intra-arterial and intra-arterial combined with blood brain barrier disruption) to determine which one optimizes the tumor cell uptake, limits the toxicity and delivers the best concomitance effect with radiotherapy. Cisplatin, oxaliplatin, their respective liposomal formulations, Lipoplatin™ and Lipoxal™, and carboplatin were assessed in F98 glioma, orthotopically implanted in Fischer rats. We found that the modest accumulation of drugs in tumor cells after intra-venous injection was significantly improved when the intra-arterial route was used and further increased after the transient opening of the blood brain barrier with mannitol. The liposomal formulations have largely reduced the toxicity and have allowed a better exploitation of the anti-cancer activity of platinum agent. Although the liposomes Lipoplatin™ and Lipoxal™ have shown a similar ability to that of carboplatin, to accumulate in brain tumors, the highest additive effect with radiotherapy was obtained with carboplatin. We conclude that the intra-arterial infusion of carboplatin or Lipoxal™ in concomitance with radiation therapy leads to the best tumor control as measured by an increase of mean survival time in Fischer rats implanted with the F98 glioma with a benefit in survival time of 13.4 and 6.5 days respectively compared to intra-venous. PMID:24026531

  17. Electrochemical Analysis of the Electrodeposition of Platinum Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hae-Min; Cho, Sung-Woon; Kim, Jun-Hyun; Kim, Chang-Koo [Ajou University, Suwon (Korea, Republic of)


    A bath for electrodeposition of platinum nanoparticles on low-cost graphite substrates was developed to attach nanoparticles directly onto a substrate, and electrochemical characteristics of the electrodeposition of platinum nanoparticles were investigated. The reaction mechanism was examined by the analysis of polarization behavior. Cyclic voltammetry measurements revealed that the electrodeposition of platinum nanoparticles was limited by mass transfer. The chronoamperometric study showed an instantaneous nucleation mechanism during the electrodeposition of platinum nanoparticles on graphite. Because graphite is much cheaper than other carbon-based substrates, the electrodeposition of platinum nanoparticles on the graphite is expected to have useful applications.

  18. Outpatient desensitization in selected patients with platinum hypersensitivity reactions. (United States)

    O'Malley, David M; Vetter, Monica Hagan; Cohn, David E; Khan, Ambar; Hays, John L


    Platinum-based chemotherapies are a standard treatment for both initial and recurrent gynecologic cancers. Given this widespread use, it is important to be aware of the features of platinum hypersensitivity reactions and the subsequent treatment of these reactions. There is also increasing interest in the development of desensitization protocols to allow patients with a history of platinum hypersensitivity to receive further platinum based therapy. In this review, we describe the management of platinum hypersensitivity reactions and the desensitization protocols utilized at our institution. We also describe the clinical categorizations utilized to triage patients to appropriate desensitization protocols. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Synthesis and characterization of new platinum(II) and platinum(IV) triphyrin complexes. (United States)

    Xue, Zhaoli; Kuzuhara, Daiki; Ikeda, Shinya; Okujima, Tetsuo; Mori, Shigeki; Uno, Hidemitsu; Yamada, Hiroko


    Metalation of 6,13,20,21-tetrakis(4-methylphenyl)-22H-tribenzo[14]triphyrin(2.1.1) with PtCl(2) gave a platinum(II) complex having a square-planar coordination structure with two pyrrolic nitrogen atoms and two chloride ions, with a saddle-shaped macrocycle. This platinum(II) complex was easily oxidized by air to an octahedral platinum(IV) complex coordinated by three pyrrolic nitrogen atoms as a tridentate monoanionic cyclic ligand and three chloride ions. When platinum(II) triphyrin was crystallized in air, an oxygen atom was incorporated between two α-carbon atoms of the pyrroles as an oxygen bridge to intercept the 14π aromatic system.

  20. Anticancer platinum (IV) prodrugs with novel modes of activity. (United States)

    Chin, Chee Fei; Wong, Daniel Yuan Qiang; Jothibasu, Ramasamy; Ang, Wee Han


    Over the past four decades, the search for improved platinum drugs based on the classical platinum (II)-diam(m)ine pharmacophore has yielded only a handful of successful candidates. New methodologies centred on platinum (IV) complexes, with better stability and expanded coordination spheres, offer the possibility of overcoming limitations inherent to platinum (II) drugs. In this review, novel strategies of targeting and killing cancer cells using platinum (IV) constructs are discussed. These approaches exploit the unique electrochemical characteristics and structural attributes of platinum (IV) complexes as a means of developing anticancer prodrugs that can target and selectively destroy cancer cells. Anticancer platinum (IV) prodrugs represent promising new strategies as targeted chemotherapeutic agents in the ongoing battle against cancer.

  1. The Dynamics of Platinum Precipitation in an Ion Exchange Membrane

    CERN Document Server

    Burlatsky, S F; Atrazhev, V V; Dmitriev, D V; Kuzminyh, N Y; Erikhman, N S


    Microscopy of polymer electrolyte membranes that have undergone operation under fuel cell conditions, have revealed a well defined band of platinum in the membrane. Here, we propose a physics based model that captures the mechanism of platinum precipitation in the polymer electrolyte membrane. While platinum is observed throughout the membrane, the preferential growth of platinum at the band of platinum is dependent on the electrochemical potential distribution in the membrane. In this paper, the location of the platinum band is calculated as a function of the gas concentration at the cathode and anode, gas diffusion coefficients and solubility constants of the gases in the membrane, which are functions of relative humidity. Under H2/N2 conditions the platinum band is located near the cathode-membrane interface, as the oxygen concentration in the cathode gas stream increases and/or the hydrogen concentration in the anode gas stream decreases, the band moves towards the anode. The model developed in this paper...

  2. Gastrointestinal permeability in ovarian cancer and breast cancer patients treated with paclitaxel and platinum

    Directory of Open Access Journals (Sweden)

    Tichá Alena


    Full Text Available Abstract Background Combination of platinum derivatives with paclitaxel is currently the standard front line regimen for patients with epithelial ovarian carcinoma, and represents also an active regimen in patients with metastatic breast or unknown primary carcinomas. Measurement of intestinal permeability represents one of the potential methods of noninvasive laboratory assessment of gastrointestinal mucositis induced by chemotherapy, but little is known about intestinal permeability in patients treated with paclitaxel or platinum. Methods Intestinal permeability was assessed in 36 breast and ovarian cancer patients treated with paclitaxel/platinum combination by measuring, using capillary gas chromatography, urinary sucrose, lactulose, xylose and mannitol after oral challenge. The significance of differences during the therapy compared to pre-treatment values was studied by Wilcoxon paired test. The differences between groups of patient were studied by Mann-Whitney U test. Fisher exact test was used to compare the frequency in different subgroups. Results After administration of the first dose, a significant (p Conclusion A transient significant increase in lactulose/monosaccharide and sucrose/monosaccharide ratios was observed in ovarian and breast cancer patients treated with paclitaxel and platinum. Increased lactulose absorption, lactulose/mannitol, sucrose/mannitol and lactulose/xylose ratios were evident in patients with grade 3 or 4 toxicity, and increased baseline lactulose/mannitol ratio predicted serious toxicity.

  3. On the enzymatic formation of platinum nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Govender, Y.; Riddin, T. L. [Rhodes University, Department of Biochemistry, Microbiology and Biotechnology (South Africa); Gericke, M. [MINTEK (South Africa); Whiteley, C. G., E-mail: [Rhodes University, Department of Biochemistry, Microbiology and Biotechnology (South Africa)


    A dimeric hydrogenase enzyme (44.5 and 39.4 kDa sub units) was isolated in a 39.5% yield from the fungus Fusarium oxysporum and purified 4.64-fold by ion exchange chromatography on Sephacryl S-200. Characterisation of the enzyme afforded pH and temperature optima of 7.5 and 38 {sup o}C, respectively, a half-life stability of 36 min and a V{sub max} and K{sub m} of 3.57 nmol min{sup -1} mL{sup -1} and 2.25 mM, respectively. This enzyme was inhibited (non-competitively) by hydrogen hexachloroplatinic acid (H{sub 2}PtCl{sub 6}) at 1 or 2 mM with a K{sub i} value of 118 {mu}M. Incubation of the platinum salt with the pure enzyme under an atmosphere of hydrogen and optimum enzyme conditions (pH 7.5, 38 {sup o}C) afforded <10% bioreduction after 8 h while at conditions suitable for platinum nanoparticle formation (pH 9, 65 {sup o}C) over 90% reduction took place after the same length of time. Cell-free extract from the fungal isolates produced nearly 90% bioreduction of the platinum salt under both pH and temperature conditions. The bioreduction of the platinum salt by a hydrogenase enzyme takes place by a passive process and not an active one as previously understood.

  4. Platinum catalysed hydrolytic amidation of unactivated nitriles

    NARCIS (Netherlands)

    Cobley, Christopher J.; Heuvel, Marco van den; Abbadi, Abdelilah; Vries, Johannes G. de


    The platinum(II) complex, [(Me2PO··H··OPMe2)PtH(PMe2OH)], efficiently catalyses the direct conversion of unactivated nitriles to N-substituted amides with both primary and secondary amines. Possible mechanisms for this reaction are discussed and evidence for initial amidine formation is reported.

  5. Skin Sensitizing Potency of Halogenated Platinum Salts. (United States)

    The relationship between occupational exposure to halogenated platinum (Pt) salts and Pt-specific allergic sensitization is well-established. Although human case reports and clinical studies demonstrate that Pt salts are potent skin sensitizers, no studies have been published tha...

  6. Platinum catalysed hydrolytic amidation of unactivated nitriles

    NARCIS (Netherlands)

    Cobley, Christopher J.; Heuvel, Marco van den; Abbadi, Abdelilah; Vries, Johannes G. de


    The platinum(II) complex, [(Me2PO··H··OPMe2)PtH(PMe2OH)], efficiently catalyses the direct conversion of unactivated nitriles to N-substituted amides with both primary and secondary amines. Possible mechanisms for this reaction are discussed and evidence for initial amidine formation is reported. Is

  7. Incorporation of a platinum center in the pi-conjugated core of push-pull chromophores for nonlinear optics (NLO). (United States)

    Durand, Raphaël J; Gauthier, Sébastien; Achelle, Sylvain; Kahlal, Samia; Saillard, Jean-Yves; Barsella, Alberto; Wojcik, Laurianne; Le Poul, Nicolas; Robin-Le Guen, Françoise


    In this article, we describe the synthesis, redox characteristics, and linear and nonlinear optical (NLO) properties of seven new unsymmetrical push-pull diacetylide platinum-based complexes. These D-π-Pt-π-A complexes incorporate pyranylidene ligands as pro-aromatic donor groups (D), diazine rings as electron-withdrawing groups (A), and various aromatic fragments (styryl or thienylvinyl) as π-linkers separating the platinum diacetylide unit from the donor and the acceptor groups. This is one of the first examples of push-pull chromophores incorporating a platinum center in the π-conjugated core. The NLO properties of these complexes were compared with those of their purely organic analogues. All compounds (organic and organometallic) exhibited positive μβ values, which dramatically increased upon methylation of the pyrimidine fragment. However, this increase was even more significant in the complexes due to the presence of platinum in the π-conjugated core. The effects of the linker on the redox and spectroscopic properties of the complexes are also discussed. In addition, DFT calculations were performed in order to gain further insight into the intramolecular charge transfer (ICT) occurring through the platinum center.

  8. Synthesis,Antibacterial and DNA-Binding of Platinum(Ⅳ)Complexes with Compounds Containing N Group%含氮杂环铂(Ⅳ)配合物的合成、抑菌性及其与DNA作用研究

    Institute of Scientific and Technical Information of China (English)

    李清萍; 宋玉民; 马新贤; 张玉梅


    New binary complexes of potassium platinum(IV ) chloride with imidazole, 2,2'-biimidazole and phenanthroline were synthesized in ethanol aqueous solution. Their composition was characterized by elemental analysis, IR, UV-Vis and TG-DTA. The composition of complexes were confirmed to be Pt( im)2C14 · H2O( I ) , PtH2biimCl4· H2O ( II) and Pt( Phen) Cl4 · H2O ( III ) , respectively. The antibacterial activity of the complexes against B. Subtitis, E. Coli and Staphyloccocus aureus was also studied, which indicated that the complexes had certain antibacterial activity. In order to further investigate the antibacterial mechanism, the interaction between platinum (IV) complexes and ct-DNA was studied with ethidium bromide (EB) probe by electronic absorption and fluorescence spectroscopy. Stem-Volmer plots showed that the quenching of fluorescence by platinum ( IV) complexes was a combined quenching process. And the binding site number n, apparent binding constant K and the corresponding thermodynamic parameters AG, AH, AS were also obtained. AH>0, AS >0 suggested that hydrophobic force played a major role in the binding of platinum (IV) complexes to DNA. Furthermore, It was also found that ionic strength had little or no effect on the binding of platinum(IV ) complexes and DNA. The values of melting temperature ( Tm ) of DNA-EB and complex-DNA-EB were determined, respectively. The experimental results indicated that platinum (IV) complexes could bind to DNA and the major binding mode was intercalative interactions.%分别以咪唑(imidazole)、2,2'-联咪唑(2,2'-biimidazole)和邻菲咯啉(phenanthroline)为配体与氯铂酸钾作用合成了三种铂(Ⅳ)二元配合物并进行了表征,确定其化学组成分别为Pt(im)2Cl4·H2O(Ⅰ),PtH2biimCl4·H2O(Ⅱ)和PtPhenCl4·H2O(Ⅲ)(im=imidazole,H2biim=2,2'-biimidazole,Phen=phenanthroline).抑菌实验结果表明这3种配合物都具有一定的抑菌作用,并以溴化乙锭为荧光探针,研究了配合物与小

  9. The effect of intermolecular hydrogen bonding on the fluorescence of a bimetallic platinum complex. (United States)

    Zhao, Guang-Jiu; Northrop, Brian H; Han, Ke-Li; Stang, Peter J


    The bimetallic platinum complexes are known as unique building blocks and arewidely utilized in the coordination-driven self-assembly of functionalized supramolecular metallacycles. Hence, photophysical study of the bimetallic platinum complexes will be very helpful for the understanding on the optical properties and further applications of coordination-driven self-assembled supramolecular metallacycles. Herein, we report steady-state and time-resolved spectroscopic experiments as well as quantum chemistry calculations to investigate the significant intermolecular hydrogen bonding effects on the intramolecular charge transfer (ICT) fluorescence of a bimetallic platinum compound 4,4'-bis(trans-Pt(PEt(3))(2)OTf)benzophenone 3 in solution. We demonstrated that the fluorescent state of compound 3 can be assigned as a metal-to-ligand charge transfer (MLCT) state. Moreover, it was observed that the formation of intermolecular hydrogen bonds can effectively lengthen the fluorescence lifetime of 3 in alcoholic solvents compared with that in hexane solvent. At the same time, the electronically excited states of 3 in solution are definitely changed by intermolecular hydrogen bonding interactions. As a consequence, we propose a new fluorescence modulation mechanism by hydrogen bonding to explain different fluorescence emissions of 3 in hydrogen-bonding solvents and nonhydrogen-bonding solvents.

  10. Concurrent chemoradiotherapy comparison of taxanes and platinum versus 5-fluorouracil and platinum in nasopharyngeal carcinoma treatment

    Institute of Scientific and Technical Information of China (English)

    Chen Xichuang; Hong Yuan; Feng Jinhua; Ye Jianlin; Zheng Panpan; Guan Xiyin; You Xiaohong


    Background Nasopharyngeal carcinoma (NPC) is a squamous-cell carcinoma especially prevailing among the natives of southern China.The regimen of concurrent chemoradiotherapy (CCRT) that include platinum and 5-fluorouracil (5-FU)is considered to be the standard treatment for NPC.However,its clinical use is limited by its toxicity.Our purpose was to evaluate the efficacy and safety of the regimen of CCRT with taxanes and platinum versus the regimen of CCRT with 5-FU and platinum in NPC treatment.Methods Medline,the Cochrane library,and the Chinese medical literature database were searched for eligible studies.Meta-analysis was performed using Review Manager (Version 5.2).Results Six random controlled trials (RCTs) including 514 patients met our criteria.Meta-analysis showed that the regimen of CCRT with taxanes and platinum had an improved significant difference in complete remission (CR) and less incidence rate in adverse reactions such as gastrointestinal impairment grades Ⅲll-Ⅳ,liver and kidney impairment grades Ⅰ-Ⅱ,and radiodermatitis grades Ⅲ-Ⅳ versus the conventional regimen of CCRT with 5-FU and platinum,while the long-term effectiveness rate of overall survival,Iocoregional failure-free survival,or distant metastasis failure-free survival between the two groups was therapeutic equivalence.Conclusions The regimen of CCRT with taxanes and platinum in NPC therapy may be more efficient and safe compared to the conventional modality of 5-FU and platinum in CCRT.However,we need more high-quality studies of multi-center and randomized double-blind clinical trials to further compare,analyze,and confirm the findings.

  11. The pilot test of Pt-Pd and Pt-Rh feeds extracted and separated with a new sulfoxide extractant

    Institute of Scientific and Technical Information of China (English)


    Platinum, palladium and rhodium of the raw feeds extracted and separated with a new sulfoxide extractant (MSO)were studied in the paper. The pilot test results showed that the percentage extractions are more than 99% for platinum and palladium in Pt-Pd feed, and the percentage strippings are 100% and 99.2% with HCl and ammonia, respectively. The ratio of palladium to platinum is 0.0016 in stripping platinum solution, and the ratio of platinum to palladium is 0.0020 in stripping palladium solution. The percentage extraction of platinum is 99% in Pt-Rh feed, and the percentage stripping is 100%.The ratio of rhodium to platinum is 0.0002 in stripping platinum solution. Therefore, platinum, palladium, and rhodium feeds are separated effectively with MSO.

  12. Bis-NHC chelate complexes of nickel(0) and platinum(0). (United States)

    Brendel, Matthias; Braun, Carolin; Rominger, Frank; Hofmann, Peter


    For a long time d(10)-ML2 fragments have been known for their potential to activate unreactive bonds by oxidative addition. In the development of more active species, two approaches have proven successful: the use of strong σ-donating ligands leading to electron-rich metal centers and the employment of chelating ligands resulting in a bent coordination geometry. Combining these two strategies, we synthesized bis-NHC chelate complexes of nickel(0) and platinum(0). Bis(1,5-cyclooctadiene)nickel(0) and -platinum(0) react with bisimidazolium salts, deprotonated in situ at room temperature, to yield tetrahedral or trigonal-planar bis-NHC chelate olefin complexes. The synthesis and characterization of these complexes as well as a first example of C-C bond activation with these systems are reported. Due to the enforced cis arrangement of two NHCs, these compounds should open interesting perspectives for bond-activation chemistry and catalysis.

  13. Microwave Assisted Synthesis, Modification With Platinum And Photocatalytical Properties of TiO2 Nanofibers

    Directory of Open Access Journals (Sweden)

    Reinis DRUNKA


    Full Text Available In the present work formation of active TiO2 nanoparticles in microwave synthesis and their modification with platinum were studied. Anatase nanopowder and 10 M KOH solution were used as raw materials. Microwave assisted synthesis method permited to obtain TiO2 nanofibres and nanowires with a diameter of 10 nm and a specific surface area in the range of 70 – 150 m2/g. In order to modify TiO2 nanofibers with platinum it was stirred in H2PtCl6 solution under UV irradiation. Photocatalytic activity was determined by degradation of the methylene blue (MB solution under UV and visible light irradiation. The obtained samples showed higher photocatalytic activity with respect to pure TiO2 nanofibers. The doped TiO2 nanofibers were appropriate for degradation of harmful organic compounds as well as for hydrogen production by water splitting.

  14. New platinum(II complexes with benzothiazole ligands

    Directory of Open Access Journals (Sweden)

    José A. Carmona-Negrón


    Full Text Available Four new platinum(II complexes, namely tetraethylammonium tribromido(2-methyl-1,3-benzothiazole-κNplatinate(II, [NEt4][PtBr3(C8H7NS] (1, tetraethylammonium tribromido(6-methoxy-2-methyl-1,3-benzothiazole-κNplatinate(II, [NEt4][PtBr3(C9H9NOS] (2, tetraethylammonium tribromido(2,5,6-trimethyl-1,3-benzothiazole-κNplatinate(II, [NEt4][PtBr3(C10H11NS] (3, and tetraethylammonium tribromido(2-methyl-5-nitro-1,3-benzothiazole-κNplatinate(II, [NEt4][PtBr3(C8H6N2O2S] (4, have been synthesized and structurally characterized by single-crystal X-ray diffraction techniques. These species are precursors of compounds with potential application in cancer chemotherapy. All four platinum(II complexes adopt the expected square-planar coordination geometry, and the benzothiazole ligand is engaged in bonding to the metal atom through the imine N atom (Pt—N. The Pt—N bond lengths are normal: 2.035 (5, 2.025 (4, 2.027 (5 and 2.041 (4 Å for complexes 1, 2, 3 and 4, respectively. The benzothiazole ligands are positioned out of the square plane, with dihedral angles ranging from 76.4 (4 to 88.1 (4°. The NEt4 cation in 3 is disordered with 0.57/0.43 occupancies.

  15. Formic acid oxidation at platinum-bismuth catalysts

    Directory of Open Access Journals (Sweden)

    Popović Ksenija Đ.


    Full Text Available The field of heterogeneous catalysis, specifically catalysis on bimetallic surfaces, has seen many advances over the past few decades. Bimetallic catalysts, which often show electronic and chemical properties that are distinct from those of their parent metals, offer the opportunity to obtain new catalysts with enhanced selectivity, activity, and stability. The oxidation of formic acid is of permanent interest as a model reaction for the mechanistic understanding of the electrooxidation of small organic molecules and because of its technical relevance for fuel cell applications. Platinum is one of the most commonly used catalysts for this reaction, despite the fact that it shows a few significant disadvantages: high cost and extreme susceptibility to poisoning by CO. To solve this problem, several approaches have been used, but generally, they all consist in the modification of platinum with a second element. Especially, bismuth has received significant attention as Pt modifier. According to the results presented in this survey dealing with the effects influencing the formic acid oxidation it was found that two types of Pt-Bi bimetallic catalysts (bulk and low loading deposits on GC showed superior catalytic activity in terms of the lower onset potential and oxidation current density, as well as exceptional stability compared to Pt. The findings in this report are important for the understanding of mechanism of formic acid electrooxidation on a bulk alloy and decorated surface, for the development of advanced anode catalysts for direct formic acid fuel cells, as well as for the synthesis of novel low-loading bimetallic catalysts. The use of bimetallic compounds as the anode catalysts is an effective solution to overcoming the problems of the formic acid oxidation current stability for long term applications. In the future, the tolerance of both CO poisoning and electrochemical leaching should be considered as the key factors in the development

  16. Ototoxicity monitoring in children treated with platinum chemotherapy. (United States)

    Brooks, Beth; Knight, Kristin


    To review the prevalence, mechanisms, clinical presentation, risk factors and implications of platinum-induced ototoxicity in paediatric cancer patients based on published evidence, discuss options for monitoring hearing in young children during treatment and review long-term follow-up guidelines. Narrative literature review. Children treated with cisplatin are at high risk of hearing loss and early, accurate identification of ototoxicity is important for medical decision making and hearing rehabilitation. Challenges of monitoring hearing in young children during cancer treatment and options for monitoring hearing are discussed. Hearing loss has important consequences for the survivors of childhood cancer including communication, learning, cognition and quality of life. Due to the presentation and configuration of ototoxic hearing loss, the test frequencies that are prioritised and the sequence of testing may differ from standard paediatric hearing evaluations. Hearing should be monitored during treatment and after completion of therapy.

  17. Detecting acute neurotoxicity during platinum chemotherapy by neurophysiological assessment of motor nerve hyperexcitability

    Directory of Open Access Journals (Sweden)

    Hill Andrew


    Full Text Available Abstract Background Platinum-based drugs, such as cisplatin and oxaliplatin, are well-known for inducing chronic sensory neuropathies but their acute and motor neurotoxicities are less well characterised. Use was made of nerve conduction studies and needle electromyography (EMG to assess motor nerve excitability in cancer patients during their first treatment cycle with platinum-based chemotherapy in this study. Methods Twenty-nine adult cancer patients had a neurophysiological assessment either before oxaliplatin plus capecitabine, on days 2 to 4 or 14 to 20 after oxaliplatin plus capecitabine, or on days 2 to 4 after carboplatin plus paclitaxel or cisplatin, undertaken by a neurophysiologist who was blinded to patient and treatment details. Patients completed a symptom questionnaire at the end of the treatment cycle. Results Abnormal spontaneous high frequency motor fibre action potentials were detected in 100% of patients (n = 6 and 72% of muscles (n = 22 on days 2 to 4 post-oxaliplatin, and in 25% of patients (n = 8 and 13% of muscles (n = 32 on days 14 to 20 post-oxaliplatin, but in none of the patients (n = 14 or muscles (n = 56 tested prior to oxaliplatin or on days 2 to 4 after carboplatin plus paclitaxel or cisplatin. Repetitive compound motor action potentials were less sensitive and less specific than spontaneous high frequency motor fibre action potentials for detection of acute oxaliplatin-induced motor nerve hyperexcitability but were present in 71% of patients (n = 7 and 32% of muscles (n = 32 on days 2 to 4 after oxaliplatin treatment. Acute neurotoxicity symptoms, most commonly cold-induced paraesthesiae and jaw or throat tightness, were reported by all patients treated with oxaliplatin (n = 22 and none of those treated with carboplatin plus paclitaxel or cisplatin (n = 6. Conclusions Abnormal spontaneous high frequency motor fibre activity is a sensitive and specific endpoint of acute oxaliplatin-induced motor nerve

  18. Influence of volatile compounds on the development of off-flavours in pig back fat samples classified with boar taint by a test panel. (United States)

    Rius, M Angels; Hortós, M; García-Regueiro, Jose Antonio


    Dynamic Head Space methodology was applied to evaluate the possible contribution of some volatile compounds to the development of boar taint in pig backfat samples with low concentrations of skatole and androstenone, but which had previously been classified as tainted by a trained test panel. Volatile compounds were collected in a trap of graphited charcoal and analysed by GC-MS in Scan mode. Aldehydes and short chain fatty acids, compounds that play a significant role in the development of undesirable aromas in food products, were the main classes of compounds identified in this study, although the possible contribution of other compounds that were detected in a minor proportion - such as alcohols and ketones - was evaluated. Styrene and 1,4-dichlorobenzene, compounds that may have come from an external contamination, showed a high concentration in the samples classified with boar taint, so these compounds could have been responsible for the development of some off-flavours in the fat samples studied in this work. In the same study, skatole and androstenone were also determined by normal phase HPLC and GCMS, respectively.

  19. Genotoxicity testing of 3,4,5-trimethylfuran-2(5H)-one, a compound from plant-derived smoke with germination inhibitory activity. (United States)

    Light, Marnie E; Anthonissen, Roel; Maes, Annemarie; Verschaeve, Luc; Pošta, Martin; Van Staden, Johannes


    Plant-derived smoke and certain smoke compounds improve seed germination and enhance seedling growth of many species. Thus, smoke-infused water and the active smoke-derived compounds have the potential to be used in different agricultural and horticultural applications. However, despite these interesting and potentially practical properties, it should also be ascertained whether such compounds may pose a health risk, particularly if they are to be used in the production of food or fodder crops. Amongst some of the aspects that would be important to understand are any possible genotoxic properties that the compounds may possess due to potential carry-over effects. Here, we report on a genotoxicity study of 3,4,5-trimethylfuran-2(5H)-one, a compound from plant-derived smoke previously shown to have germination inhibitory activity. Using two in vitro tests, namely the bacterial VITOTOX® test (with/without S9 metabolic activation) and the cytome assay on human C3A cells, no genotoxicity or toxicity was found. Furthermore, these results support a previous study where a related smoke-derived compound with germination promoting properties was investigated.

  20. Substrate-dependent modulation of CYP3A4 catalytic activity: analysis of 27 test compounds with four fluorometric substrates. (United States)

    Stresser, D M; Blanchard, A P; Turner, S D; Erve, J C; Dandeneau, A A; Miller, V P; Crespi, C L


    Inhibition of cytochrome P450 catalytic activity is a principal mechanism for pharmacokinetic drug-drug interactions. Rapid, in vitro testing for cytochrome P450 inhibition potential is part of the current paradigm for identifying drug candidates likely to give such interactions. We have explored the extent that qualitative and quantitative inhibition parameters are dependent on the cytochrome P450 (CYP) 3A4 probe substrate. Inhibition potential (e.g., IC(50) values from 8-point inhibition curves) or activation potential for most compounds varied dramatically depending on the fluorometric probe substrates for CYP3A4 [benzyloxyresorufin (BzRes), 7-benzyloxy-4-trifluoromethylcoumarin (BFC), 7-benzyloxyquinoline (BQ), and dibenzylfluorescein (DBF)]. For 21 compounds that were primarily inhibitors, the range of IC(50) values for the four substrates varied from 2.1- to 195-fold with an average of 29-fold. While the rank order of sensitivity among the fluorometric substrates varied among the individual inhibitors, on average, BFC dealkylation was the most sensitive to inhibition, while BQ dealkylation was least sensitive. Partial inhibition was observed with BzRes and BQ but not for BFC and DBF. BzRes was more prone to activation, whereas dramatic changes in IC(50) values were observed when the BQ concentration was below the S(50). Three different correlation analyses indicated that IC(50) values with BFC, BQ, and DBF correlated well with each other, whereas the response with BzRes correlated more weakly with the other substrates. One of these correlation analyses was extended to the percent inhibition of 10 microM inhibitor with the standard CYP3A4 probe substrates testosterone, midazolam, and nifedipine. In this analysis the responses with BQ, BFC and DBF correlated well with testosterone and midazolam but more poorly with nifedipine. In the aggregate, BFC and DBF appear more suitable as an initial screen for CYP3A4 inhibition. However, the substrate-dependent effects

  1. Remarkable NO oxidation on single supported platinum atoms. (United States)

    Narula, Chaitanya K; Allard, Lawrence F; Stocks, G M; Moses-DeBusk, Melanie


    Our first-principles density functional theoretical modeling suggests that NO oxidation is feasible on fully oxidized single θ-Al2O3 supported platinum atoms via a modified Langmuir-Hinshelwood pathway. This is in contrast to the known decrease in NO oxidation activity of supported platinum with decreasing Pt particle size believed to be due to increased platinum oxidation. In order to validate our theoretical study, we evaluated single θ-Al2O3 supported platinum atoms and found them to exhibit remarkable NO oxidation activity. A comparison of turnover frequencies (TOF) of single supported Pt atoms with those of platinum particles for NO oxidation shows that single supported Pt atoms are as active as fully formed platinum particles. Thus, the overall picture of NO oxidation on supported Pt is that NO oxidation activity decreases with decreasing Pt particle size but accelerates when Pt is present only as single atoms.

  2. Synthesis of Bimetallic Platinum Nanoparticles for Biosensors

    Directory of Open Access Journals (Sweden)

    Gerard M. Leteba


    Full Text Available The use of magnetic nanomaterials in biosensing applications is growing as a consequence of their remarkable properties; but controlling the composition and shape of metallic nanoalloys is problematic when more than one precursor is required for wet chemistry synthesis. We have developed a successful simultaneous reduction method for preparation of near-spherical platinum-based nanoalloys containing magnetic solutes. We avoided particular difficulties in preparing platinum nanoalloys containing Ni, Co and Fe by the identification of appropriate synthesis temperatures and chemistry. We used transmission electron microscopy (TEM to show that our particles have a narrow size distribution, uniform size and morphology, and good crystallinity in the as-synthesized condition. Energy dispersive spectroscopy (EDS and X-ray diffraction (XRD confirms the coexistence of Pt with the magnetic solute in a face-centered cubic (FCC solid solution.

  3. Catalytic converters as a source of platinum

    Directory of Open Access Journals (Sweden)

    A. Fornalczyk


    Full Text Available The increase of Platinum Group Metals demand in automotive industry is connected with growing amount of cars equipped with the catalytic converters. The paper presents the review of available technologies during recycling process. The possibility of removing platinum from the used catalytic converters applying pyrometallurgical and hyrdometallurgical methods were also investigated. Metals such as Cu, Pb, Ca, Mg, Cd were used in the pyrometallurgical research (catalytic converter was melted with Cu, Pb and Ca or Mg and Cd vapours were blown through the whole carrier. In hydrometallurgical research catalytic converters was dissolved in aqua regia. Analysis of Pt contents in the carrier before and after the process was performed by means of atomic absorption spectroscopy. Obtained result were discussed.

  4. Examining the surfaces in used platinum catalysts

    Directory of Open Access Journals (Sweden)

    Trumić B.


    Full Text Available For the purpose of finding more advanced platinum catalyst manufacturing technologies and achieving a higher degree of ammonia oxidation, metallographic characterization has been done on the surface of catalyst gauzes and catalyst gripper gauzes made from platinum and palladium alloys. For the examined samples of gauzes as well as the cross section of the wires, a chemical analysis was provided. The purpose of this paper is the metallographic characterization of examined alloys carried out by way of electronic microscopic scanning, X-rays as well as chemical assays which contributed greatly to a better understanding of the surface deactivation, in other words a better consideration of structural changes occurring on the wire surface.

  5. Considerations in Platinum and Gold Drug Design and the Synthesis of Chloro(2,3-Diphenyl-1,3,4-Thiadiazolium-5-Thiolato-Sexo)Gold(I): The First Gold Meso-Ionic Complex of Its Kind (United States)

    Howe, B. P.


    It is evident that the chemistry of platinum is in a more advanced state than that of gold, mainly due to the success of the former in several anti-cancer drugs. With a view to finding possible, new candidates with chemotherapeutic potential, the use of sulphur-donor ligands bonded to platinum and gold is discussed herein in an attempt to promote the need to investigate similar ligands. Chloro(2,3-diphenyl-1,3,4-thiadiazolium-5-thiolato-Sexo)gold(I) has been synthesised using a standard reaction, whereby Au(III) is initially reduced to Au(I) then reacted with the ligand, 2,3-diphenyl-1,3,4-thiadiazolium-5-thiolate.hydrochloride, isolated and finally characterised by elemental analyses and infrared spectroscopy. The compound is the first example of gold attached to a meso-ionic compound. It has also been tested for anti-bacterial and anti-fungal activity and shown to possess moderate activity against Gram-positive bacteria, although is inactive against, Gram-negative bacteria and fungi. PMID:18475799

  6. Do Scarce Precious Metals Equate to Safe Harbor Investments? The Case of Platinum and Palladium

    Directory of Open Access Journals (Sweden)

    John Francis T. Diaz


    Full Text Available This research establishes the predictability and safe harbor properties of two scarce precious metals, namely, platinum and palladium. Utilizing their spot prices, the study concludes intermediate memory in the return structures of both precious metals, which implies the instability of platinum and palladium returns’ persistency in the long run. However, both the ARFIMA-FIGARCH and the ARFIMA-FIAPARCH models confirm long-memory properties in the volatility of the two spot prices. The leverage effects phenomenon is not also present based on the ARFIMA-APARCH and ARFIMA-FIAPARCH models, which may possibly conclude the resilience of both precious metals against increased volatility. However, further tests proved that only platinum has a symmetric volatility response to shocks with the presence of negative gamma parameter, which proves that only platinum can be considered a safe harbor investment, because negative and positive shocks have equal effects on their returns and volatilities. Comparing the four models utilized in this study, the combined ARFIMA-FIAPARCH models are the best fitting model to characterize both precious metals’ spot prices.

  7. The laser welding of iridium-platinum tips to spark plug electrodes (United States)

    Antoszewski, Bogdan; Tofil, Szymon


    The paper presents selected results of model and technological experiments of welding iridium-platinum tips to spark plug electrodes. Variants of welding technology included different ways of preparing materials and the use of different Nd: YAG lasers (Rofin BLS 720 and Rofin Integral). The results of technological tests were verified by the metallographic evaluation of joints. Performance tests when powered by biogas were conducted for selected variants of welding.

  8. Stability of Porous Platinum Nanoparticles: Combined In Situ TEM and Theoretical Study

    DEFF Research Database (Denmark)

    Chang, Shery L. Y.; Barnard, Amanda S.; Dwyer, Christian


    Porous platinum nanoparticles provide a route for the development of catalysts that use less platinum without sacrificing catalytic performance. Here, we examine porous platinum nanoparticles using a combination of in situ transmission electron microscopy and calculations based on a first...

  9. Platinum Acetylide Two-Photon Chromophores (Preprint) (United States)


    the higher energy range that lead to its photodegradation . Secondly, because there is a quadratic dependence of two-photon absorption (2PA) on either an electron donating amino- fluorenyl or electron withdrawing benzothiazolyl-fluorene that are themselves known as two-photon absorbing dyes ...groups in place of phenyl groups have shown a doubling of the intrinsic cr2value at 740 nm.40,41In this paper we describe novel platinum dyes that

  10. Redeposition of electrochemically dissolved platinum as nanoparticles on carbon

    DEFF Research Database (Denmark)

    Norgaard, C. F.; Stamatin, S. N.; Skou, E. M.


    Electrochemical dissolution of platinum has been proposed by several research groups as an environmentally friendly way to recover platinum from catalytic structures such as fuel cell electrodes. For the case of electrochemical dissolution of platinum in hydrochloric acid electrolyte, the present...... on carbon was then identified, quantified, and the particle size evaluated by powder X-ray diffraction, thermogravimetric analysis and cyclic voltammetry. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved....

  11. Platinum germanium ordering in UPtGe (United States)

    Hoffmann, Rolf-Dieter; Pöttgen, Rainer; Lander, Gerry H.; Rebizant, Jean


    The non-centrosymmetric structure of UPtGe was investigated by X-ray diffraction on both powders and single crystals: EuAuGe type, Imm2, a=432.86(5), b=718.81(8), c=751.66(9) pm, wR2=0.0738 for 399 F2 values and 22 variables. The platinum and germanium atoms form two-dimensional layers of puckered Pt 3Ge 3 hexagons with short PtGe intralayer distances of 252 and 253 pm. These condensed two-dimensionally infinite nets are interconnected to each other via weak PtPt contacts with bond distances of 300 pm. The two crystallographically independent uranium atoms are situated above and below the six-membered platinum-germanium rings. The U1 atoms have six closer germanium neighbors while the U2 atoms have six closer platinum neighbors. The group-subgroup relation with the KHg 2 type structure is presented.

  12. Preparation and Electrochemical Properties of Porous Platinum Electrode

    Institute of Scientific and Technical Information of China (English)

    HE Xin; CHEN Boxun; CHEN Qiao


    Porous platinum electrodes were prepared by adding YSZ,as an active material,in platinum paste.Relationship between microstructure and electrochemical performance of O2(g),Pt/YSZ electrode have been characterized by SEM and cyclic voltammetry.Results showed that the microstructure of platinum electrode is a significant impact on the cyclic voltammetry.With the increase of platinum electrode's porosity,the area of three-phase boundary of O2(g)/Pt/YSZ was increased.The electrochemical reactivity was also enhanced.These were presented as the increase of current density and cathode voltage in cyclic voltammetry.

  13. Controlled synthesis of porous platinum nanostructures for catalytic applications. (United States)

    Cao, Yanqin; Zhang, Junwei; Yang, Yong; Huang, Zhengren; Long, Nguyen Viet; Nogami, Masayuki


    Porous platinum, that has outstanding catalytic and electrical properties and superior resistant characteristics to corrosion, has been widely applied in chemical, petrochemical, pharmaceutical, electronic, and automotive industries. As the catalytic activity and selectivity depend on the size, shape and structure of nanomaterials, the strategies for controlling these factors of platinum nanomaterials to get excellent catalytic properties are discussed. Here, recent advances in the design and preparation of various porous platinum nanostructures are reviewed, including wet-chemical synthesis, electro-deposition, galvanic replacement reaction and de-alloying technology. The applications of various platinum nanostructures are also discussed, especially in fuel cells.

  14. Síntese e caracterização de novos complexos de platina (II com ligantes derivados do furano e nitrofurano Synthesis and characterization of new platinum (II complexes containing furan and nitrofuran derived ligands

    Directory of Open Access Journals (Sweden)

    Wendell Guerra


    Full Text Available Platinum (II complexes, for example, cisplatin and carboplatin, have been used as chemotherapeutic agents for the treatment of various types of cancer. Several other complexes of this metallic ion are also under clinical evaluation. This work describes the synthesis of five new platinum (II complexes having furan and 5-nitrofuran derivatives and chloride as ligands. The compounds were characterized by NMR, IR and elemental analysis.

  15. Comparative studies of oxaliplatin-based platinum(iv) complexes in different in vitro and in vivo tumor models. (United States)

    Göschl, Simone; Schreiber-Brynzak, Ekaterina; Pichler, Verena; Cseh, Klaudia; Heffeter, Petra; Jungwirth, Ute; Jakupec, Michael A; Berger, Walter; Keppler, Bernhard K


    Using platinum(iv) prodrugs of clinically established platinum(ii) compounds is a strategy to overcome side effects and acquired resistances. We studied four oxaliplatin-derived platinum(iv) complexes with varying axial ligands in various in vitro and in vivo settings. The ability to interfere with DNA (pUC19) in the presence and absence of a reducing agent (ascorbic acid) was investigated in cell-free experiments. Cytotoxicity was compared under normoxic and hypoxic conditions in monolayer cultures and multicellular spheroids of colon carcinoma cell lines. Effects on the cell cycle were investigated by flow cytometry, and the capacity of inducing apoptosis was confirmed by flow cytometry and Western blotting. The anti-cancer activity of one complex was studied in vivo in immunodeficient and immunocompetent mice, and the platinum levels in various organs and the tumor after treatment were quantified. The results demonstrate that modification of the axial ligands can improve the cytotoxic potency. The complexes are able to interfere with plasmid DNA, which is enhanced by co-incubation with a reducing agent, and cause cell cycle perturbations. At higher concentrations, they induce apoptosis, but generate only low levels of reactive oxygen species. Two of the complexes increase the life span of leukemia (L1210) bearing mice, and one showed effects similar to oxaliplatin in a CT26 solid tumor model, despite the low platinum levels in the tumor. As in the case of oxaliplatin, activity in the latter model depends on an intact immune system. These findings show new perspectives for the development of platinum(iv) prodrugs of the anticancer agent oxaliplatin, combining bioreductive properties and immunogenic aspects.

  16. DNA interactions of new cytotoxic tetrafunctional dinuclear platinum complex trans,trans-[{PtCl2(NH3)}2(piperazine)]. (United States)

    Brabec, Viktor; Christofis, Petros; Slámová, Martina; Kostrhunová, Hana; Nováková, Olga; Najajreh, Yousef; Gibson, Dan; Kaspárková, Jana


    A new tetrafunctional dinuclear platinum complex trans,trans-[{PtCl2(NH3)}2(piperazine)] with sterically rigid linking group was designed, synthesized and characterized. In this novel molecule, the DNA-binding features of two classes of the platinum compounds with proven antitumor activity are combined, namely trans oriented bifunctional mononuclear platinum complexes with a heterocyclic ligand and polynuclear platinum complexes. DNA-binding mode of this new complex was analyzed by various methods of molecular biology and biophysics. The complex coordinates DNA in a unique way and interstrand and intrastrand cross-links are the predominant lesions formed in DNA in cell-free media and in absence of proteins. An intriguing aspect of trans,trans-[{PtCl2(NH3)}2(piperazine)] is that, using a semi-rigid linker, interstrand cross-linking is diminished relative to other dinuclear platinum complexes with flexible linking groups and lesions that span several base pairs, such as tri- and tetrafunctional adducts, become unlikely. In addition, in contrast to the inability of trans,trans-[{PtCl2(NH3)}2(piperazine)] to cross-link two DNA duplexes, the results of the present work convincingly demonstrate that this dinuclear platinum complex forms specific DNA lesions which can efficiently cross-link proteins to DNA. The results substantiate the view that trans,trans-[{PtCl2(NH3)}2(piperazine)] or its analogues could be used as a tool for studies of DNA properties and their interactions or as a potential antitumor agent. The latter view is also corroborated by the observation that trans,trans-[{PtCl2(NH3)}2(piperazine)] is a more effective cytotoxic agent than cisplatin against human tumor ovarian cell lines.

  17. Testing an alternative search algorithm for compound identification with the 'Wiley Registry of Tandem Mass Spectral Data, MSforID'. (United States)

    Oberacher, Herbert; Whitley, Graeme; Berger, Bernd; Weinmann, Wolfgang


    A tandem mass spectral database system consists of a library of reference spectra and a search program. State-of-the-art search programs show a high tolerance for variability in compound-specific fragmentation patterns produced by collision-induced decomposition and enable sensitive and specific 'identity search'. In this communication, performance characteristics of two search algorithms combined with the 'Wiley Registry of Tandem Mass Spectral Data, MSforID' (Wiley Registry MSMS, John Wiley and Sons, Hoboken, NJ, USA) were evaluated. The search algorithms tested were the MSMS search algorithm implemented in the NIST MS Search program 2.0g (NIST, Gaithersburg, MD, USA) and the MSforID algorithm (John Wiley and Sons, Hoboken, NJ, USA). Sample spectra were acquired on different instruments and, thus, covered a broad range of possible experimental conditions or were generated in silico. For each algorithm, more than 30,000 matches were performed. Statistical evaluation of the library search results revealed that principally both search algorithms can be combined with the Wiley Registry MSMS to create a reliable identification tool. It appears, however, that a higher degree of spectral similarity is necessary to obtain a correct match with the NIST MS Search program. This characteristic of the NIST MS Search program has a positive effect on specificity as it helps to avoid false positive matches (type I errors), but reduces sensitivity. Thus, particularly with sample spectra acquired on instruments differing in their setup from tandem-in-space type fragmentation, a comparably higher number of false negative matches (type II errors) were observed by searching the Wiley Registry MSMS.

  18. Multipurpose Compound (United States)


    Specially formulated derivatives of an unusual basic compound known as Alcide may be the answer to effective treatment and prevention of the disease bovine mastitis, a bacterial inflammation of a cow's mammary gland that results in loss of milk production and in extreme cases, death. Manufactured by Alcide Corporation the Alcide compound has killed all tested bacteria, virus and fungi, shortly after contact, with minimal toxic effects on humans or animals. Alcide Corporation credits the existence of the mastitis treatment/prevention products to assistance provided the company by NERAC, Inc.

  19. Relative developmental toxicity of glycol ether alkoxy acid metabolites in the embryonic stem cell test as compared with the in vivo potency of their parent compounds

    NARCIS (Netherlands)

    Jong, E. de; Louisse, J.; Verwei, M.; Blaauboer, B.J.; Sandt, J.J.M. van de; Woutersen, R.A.; Rietjens, I.M.C.M.; Piersma, A.H.


    The embryonic stem cell test (EST) has been proposed as an in vitro assay that might reduce animal experimentation in regulatory developmental toxicology. So far, evaluation of the EST was not performed using compounds within distinct chemical classes. Evaluation within a distinct class of chemicall

  20. Multiple testing issues in discriminating compound-related peaks and chromatograms from high frequency noise, spikes and solvent-based nois in LC-MS data sets

    NARCIS (Netherlands)

    Nyangoma, S.O.; Van Kampen, A.A.; Reijmers, T.H.; Govorukhina, N.I; van der Zee, A.G.; Billingham, I.J; Bischoff, Rainer; Jansen, R.C.


    Multiple testing issues in discriminating compound-related peaks and chromatograms from high frequency noise, spikes and solvent-based noise in LC-MS data sets.Nyangoma SO, van Kampen AA, Reijmers TH, Govorukhina NI, van der Zee AG, Billingham LJ, Bischoff R, Jansen RC. University of Birmingham. Liq

  1. How much platinum passes the placental barrier? Analysis of platinum applications in 21 patients with cervical cancer during pregnancy. (United States)

    Köhler, Christhardt; Oppelt, Peter; Favero, Giovanni; Morgenstern, Bernd; Runnebaum, Ingo; Tsunoda, Audrey; Schmittel, Alexander; Schneider, Achim; Mueller, Michael; Marnitz, Simone


    Cervical cancer is the most common solid cancer diagnosed in pregnancy. Platinum is an active drug in the treatment of patients with cervical cancer. In the second and third trimesters, platinum is used to prevent cancer progression until fetal maturity is reached. However, knowledge about the transplacental passage of platinum is very limited. Between May 2008 and June 2014, platinum-based neoadjuvant chemotherapy was applied to 21 consecutive patients with cervical cancer diagnosed in their second trimester. At the time of delivery by cesarean delivery, synchronous samples from maternal blood, umbilical cord blood, and amniotic fluid were taken and analyzed for platinum concentrations. The mean week of gestation at cancer diagnosis was 17 (13-23). On average 3 (range, 2-4) cycles of chemotherapy were applied. Cesarean deliveries were carried out between 30.4 and 36.5 weeks of gestation. Twenty-two healthy babies without renal, hepatic, auditory, or hematopoietic impairment were delivered. Platinum concentrations in umbilical cord blood and amniotic fluid were 23-65% and 11-42% of the maternal blood, respectively. This series on in vivo measurement of platinum concentrations in the fetomaternal compartment observed that because of consistently lower platinum values in the fetoplacental unit, a placental filtration mechanism of platinum may be assumed. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. An in vitro embryotoxicity assay based on the disturbance of the differentiation of murine embryonic stem cells into endothelial cells. II. Testing of compounds. (United States)

    Festag, Matthias; Viertel, Bruno; Steinberg, Pablo; Sehner, Claudia


    The embryonic stem cell test (EST) developed by Spielmann et al. [Spielmann, H., Pohl, I., Doering, B., Liebsch, M., Moldenhauer, F., 1997. The embryonic stem cell test, an in vitro embryotoxicity test using two permanent mouse cell lines: 3T3 fibroblasts and embryonic stem cells. In Vitro. Toxicol. 10, 119-127] is currently the most promising in vitro assay to predict the embryotoxic potential of compounds. In this assay the disturbance of the differentiation of embryonic stem (ES) cells into contracting cardiomyocytes by test compounds as well as the direct cytotoxicity of the test compounds on ES cells and 3T3 fibroblasts is analyzed. On the basis of these results and by applying a biostatistical prediction model (PM) [Genschow, E., Scholz, G., Brown, N., Piersma, A., Brady, M., Clemann, N., Huuskonen, H., Paillard, F., Bremer, S., Becker, K., Spielmann, H., 2000. Development of prediction models for three in vitro embryotoxicity tests in an ECVAM validation study. In Vitr. Mol. Toxicol. 13, 51-66; Genschow, E., Spielmann, H., Scholz, G., Pohl, I., Seiler, A., Clemann, N., Bremer, S., Becker, K., 2004. Validation of the embryonic stem cell test in the international ECVAM validation study on three in vitro embryotoxicity tests. Altern. Lab. Anim. 32, 209-244; Genschow, E., Spielmann, H., Scholz, G., Seiler, A., Brown, N., Piersma, A., Brady, M., Clemann, N., Huuskonen, H., Paillard, F., Bremer, S., Becker, K., 2002. The ECVAM international validation study on in vitro embryotoxicity tests: results of the definitive phase and evaluation of prediction models. European Centre for the Validation of Alternative Methods. Altern. Lab. Anim. 30, 151-176] test compounds can be classified as non-embryotoxic, weakly or strongly embryotoxic. In order to introduce a further endpoint into the EST, the disturbance of vasculogenesis and/or angiogenesis, a protocol to differentiate ES cells into endothelial cells, was established in the accompanying paper. PECAM-1 and VE

  3. Electrocatalytic activity of platinum nanoparticles supported on nanosilicon

    Energy Technology Data Exchange (ETDEWEB)

    Miu, M.; Kleps, I.; Danila, M.; Ignat, T.; Simion, M.; Bragaru, A.; Dinescu, A. [Laboratory of Nanotechnology, National Institute for Research and Development in Microtechnologies, Bucharest (Romania)


    Platinum (Pt) nanocatalysts were deposited on/inside of nanostructured silicon (nanoSi) matrix using physico-chemical methods, i.e. E-beam high vacuum Pt thin film and, respectively, chemically loaded Pt nanoparticles from hexachloroplatinic acid aqueous or alcoholic precursor solutions. High resolution morphological characterisations, completed by microstructural and compositional analyses have been performed to characterise the nanoSi catalyst support and to investigate the Pt thin film nanostructuration as well as the nanoparticle attachment and clustering processes, evidencing the controlling factors and conditions of the size, morphology and distribution. Furthermore, the experimental structures have been subjected to different electrochemical tests and it was revealed that significant improvement of the long term catalyst stability was achieved when the metal-porous Si nanoassemblies is formed, which represents a step closer to the realisation of the monolithic integrated Si-based microfabricated fuel cell. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  4. A Multimethod Approach for Investigating Algal Toxicity of Platinum Nanoparticles

    DEFF Research Database (Denmark)

    Sørensen, Sara Nørgaard; Engelbrekt, Christian; Lützhøft, Hans-Christian Holten


    The ecotoxicity of platinum nanoparticles (PtNPs) widely used in for example automotive catalytic converters, is largely unknown. This study employs various characterization techniques and toxicity end points to investigate PtNP toxicity toward the green microalgae Pseudokirchneriella subcapitata...... and Chlamydomonas reinhardtii. Growth rate inhibition occurred in standard ISO tests (EC50 values of 15–200 mg Pt/L), but also in a double-vial setup, separating cells from PtNPs, thus demonstrating shading as an important artifact for PtNP toxicity. Negligible membrane damage, but substantial oxidative stress...... was detected at 0.1–80 mg Pt/L in both algal species using flow cytometry. PtNPs caused growth rate inhibition and oxidative stress in P. subcapitata, beyond what was accounted for by dissolved Pt, indicating NP-specific toxicity of PtNPs. Overall, P. subcapitata was found to be more sensitive toward Pt...

  5. Tin-Platinum catalysts interactions on titania and silica

    Energy Technology Data Exchange (ETDEWEB)

    Nava, N. [Instituto Mexicano del Petroleo Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)], E-mail:; Del Angel, P. [Instituto Mexicano del Petroleo Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Salmones, J. [Instituto Politecnico Nacional-ESIQIE UPALM, 07738 Mexico, D.F. (Mexico); Baggio-Saitovitch, E. [Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud 150, 22290-180 Rio de Janeiro, Brasil (Brazil); Santiago, P. [Instituto de Fisica, UNAM, Mexico, D. F., 04510 Mexico (Mexico)


    Pt-Sn was supported on titania and silica, and the resulting interactions between the components in prepared samples and the resulting interactions between the components before and after treatment with hydrogen were characterized by Moessbauer spectroscopy, X-ray diffraction, Rietveld refinement, high-resolution transmission electron microscopy (HRTEM) and catalytic tests data. Results show the presence of Pt and SnO{sub 2} after calcinations, and Pt{sub 3}Sn, PtSn and PtSn{sub 3} after reduction. Rietveld analysis shows that some Ti{sup 4+} are replaced by Sn{sup 4+} atoms in the titania structure. Finally, HRTEM and the practically absence of activity observed confirms that metallic platinum is encapsulated.

  6. Streamlined Approach for (SAFER) Plan for Corrective Action Unit 566: E-MAD Compound, Nevada Test Site, Nevada, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Mark Krauss


    This Streamlined Approach for Environmental Restoration (SAFER) Plan addresses the actions needed to achieve closure for Corrective Action Unit (CAU) 566, EMAD Compound, identified in the Federal Facility Agreement and Consent Order (FFACO). Corrective Action Unit 566 comprises the following corrective action site (CAS) located in Area 25 of the Nevada Test Site: • 25-99-20, EMAD Compound This plan provides the methodology for field activities needed to gather the necessary information for closing CAS 25-99-20. There is sufficient information and process knowledge from historical documentation and investigations of similar sites regarding the expected nature and extent of potential contaminants to recommend closure of CAU 566 using the SAFER process. Additional information will be obtained by conducting a field investigation before selecting the appropriate corrective action. It is anticipated that the results of the field investigation and implementation of a corrective action of clean closure will support a defensible recommendation that no further corrective action is necessary. If it is determined that complete clean closure cannot be accomplished during the SAFER, then a hold point will have been reached and the Nevada Division of Environmental Protection (NDEP) will be consulted to determine whether the remaining contamination will be closed under the alternative corrective action of closure in place. This will be presented in a closure report that will be prepared and submitted to NDEP for review and approval. The data quality objective (DQO) strategy for CAU 566 was developed at a meeting on April 30, 2009, by representatives of NDEP and the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office. The DQO process was used to identify and define the type, amount, and quality of data needed to determine and implement appropriate corrective actions for CAU 566. The following text summarizes the SAFER activities that will

  7. Cell membrane penetration and mitochondrial targeting by platinum-decorated ceria nanoparticles (United States)

    Torrano, Adriano A.; Herrmann, Rudolf; Strobel, Claudia; Rennhak, Markus; Engelke, Hanna; Reller, Armin; Hilger, Ingrid; Wixforth, Achim; Bräuchle, Christoph


    In this work we investigate the interaction between endothelial cells and nanoparticles emitted by catalytic converters. Although catalyst-derived particles are recognized as growing burden added to environmental pollution, very little is known about their health impact. We use platinum-decorated ceria nanoparticles as model compounds for the actual emitted particles and focus on their fast uptake and association with mitochondria, the cell's powerhouse. Using live-cell imaging and electron microscopy we clearly show that 46 nm platinum-decorated ceria nanoparticles can rapidly penetrate cell membranes and reach the cytosol. Moreover, if suitably targeted, these particles are able to selectively attach to mitochondria. These results are complemented by cytotoxicity assays, thus providing insights into the biological effects of these particles on cells. Interestingly, no permanent membrane disruption or any other significant adverse effects on cells were observed. The unusual uptake behavior observed for 46 nm nanoparticles was not observed for equivalent but larger 143 nm and 285 nm platinum-decorated particles. Our results demonstrate a remarkable particle size effect in which particles smaller than ~50-100 nm escape the usual endocytic pathway and translocate directly into the cytosol, while particles larger than ~150 nm are internalized by conventional endocytosis. Since the small particles are able to bypass endocytosis they could be explored as drug and gene delivery vehicles. Platinum-decorated nanoparticles are therefore highly interesting in the fields of nanotoxicology and nanomedicine.In this work we investigate the interaction between endothelial cells and nanoparticles emitted by catalytic converters. Although catalyst-derived particles are recognized as growing burden added to environmental pollution, very little is known about their health impact. We use platinum-decorated ceria nanoparticles as model compounds for the actual emitted particles and

  8. Biological evaluation of a novel Herceptin-platinum (II) conjugate for efficient and cancer cell specific delivery. (United States)

    Huang, Rong; Sun, Yu; Zhang, Xiang-yang; Sun, Bai-wang; Wang, Qiu-cui; Zhu, Jin


    Platinum-based drugs have been widely used for the treatment of malignant tumors. However, their applications are limited by severe side effects for their lack of selectivity for cancer cells. The development of antibody drug conjugates (ADCs) have provided a platform to reduce drug toxicity and improve drug efficacy. Here we describe a nover conjugate comprising of Herceptin (an anti-HER2 antibody) and platinum drug via a cathepsin B cleavable dipetide for enhancing drug accumulation and HER2-positive cancer cell specific delivery. This conjugate is believed to be cleaved by cathepsin B, leading to a 1,6-elimination reaction and activation of drug release. Herceptin-Pt(II) is evaluated to have approximately loaded with 6.4 moles platinum drugs per mole of antibody. We demonstrate that Herceptin-Pt(II) retain high and selective binding affinity for HER2 protein and HER2-positive SK-BR-3 cancer cells. The in vitro cytotoxicity tests indicate that Herceptin-Pt(II) exhibits much higher cytotoxicity than oxaliplatin against SK-BR-3 cells. More importantly, Herceptin-Pt(II) shows no obvious inhibition against the growth of both MCF-7 and MDA-MB-231 cells, which express lower levels of HER2. Furthermore, compared with free oxaliplatin, Herceptin significantly improved the cellular uptake of platinum drugs in SK-BR-3 cells. In summary, Herceptin-platinum (II) conjugate is a remarkable and potent platform for efficient and cancer cell specific delivery.

  9. Length of tick repellency depends on formulation of the repellent compound (icaridin = Saltidin®): tests on Ixodes persulcatus and Ixodes ricinus placed on hands and clothes. (United States)

    Abdel-Ghaffar, Fathy; Al-Quraishy, Saleh; Mehlhorn, Heinz


    The present study had the aim to test the repellent potential of the compound icaridin = Saltidin® against the tick species Ixodes ricinus and Ixodes persulcatus using different formulations of the compound. Tests were done on backs of impregnated human hands, on impregnated linen cloth and versus impregnated dog hair. It was found that 1. Ixodes persulcatus-the common Eastern European, Russian Ixodes species is significantly sensitive to icaridin = Saltidin® as I. ricinus protecting for the test period of 5 h. This is an important finding, since I. persulcatus is the vector of agents of the severe Eastern meningoencephalitis; 2. that this repellent compound acts similarly on both I. ricinus and I. persulcatus, when sprayed either on naked skin or on cloths; 3. that there are only slight differences in duration of the repellency when using different formulations containing icaridin = Saltidin®; 4. that icaridin = Saltidin® sprayed on dog hair has identical repellent effects like those seen on human skin and cloths; thus, this compound can also be used to protect animals such as dogs, cats, horses; and 5. that the icaridin = Saltidin® did not induce a bad sensation on skin, nor bad smells; furthermore, it was not sticky and did not leave residuals neither on clothes nor on dog's hair.

  10. Modelling and sensitivity analysis of urinary platinum excretion in anticancer chemotherapy for the recovery of platinum

    DEFF Research Database (Denmark)

    Folens, Karel; Mortier, Séverine Thérèse F C; Baeten, Janis


    Platinum (Pt) based antineoplastics are important in cancer therapy. To date the Pt which is urinary excreted by the patients ends up in wastewater. This is disadvantageous from both an economic as from an ecological point of view because Pt is a valuable material and the excretion products are t...

  11. Exhaust system having a gold-platinum group metal catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Ragle, Christie Susan [Havana, IL; Silver, Ronald G [Peoria, IL; Zemskova, Svetlana Mikhailovna [Edelstein, IL; Eckstein, Colleen J [Metamora, IL


    A method of providing an exhaust treatment device is disclosed. The method includes applying a catalyst including gold and a platinum group metal to a particulate filter. The concentration of the gold and the platinum group metal is sufficient to enable oxidation of carbon monoxide and nitric oxide.

  12. Corrosion Studies of Platinum Nano-Particles for Fuel Cells

    DEFF Research Database (Denmark)

    Shim, Signe Sarah

    The main focus of the present thesis is on corrosion and prevention of corrosion of platinum particles supported on carbon. This is important for instance in connection with start up and shutdown of fuel cells. The degradation mechanism of platinum particles supported on carbon has been...

  13. Antitumor activity of phenylene bridged binuclear bis(imino-quinolyl)palladium(II) and platinum(II) complexes. (United States)

    Motswainyana, William M; Onani, Martin O; Madiehe, Abram M; Saibu, Morounke


    Antitumor effects of a known bis(imino-quinolyl)palladium(II) complex 1 and its newly synthesized platinum(II) analogue 2 were evaluated against human breast (MCF-7) and human colon (HT-29) cancer cell lines. The complexes gave cytotoxicity profiles that were better than the reference drug cisplatin. The highest cytotoxic activities were pronounced in complex 2 across the two examined cancer cell lines. Both compounds represent potential active drugs based on bimetallic complexes.

  14. Noble Metal Catalysts for Mercury Oxidation in Utility Flue Gas: Gold, Palladium and Platinum Formulations

    Energy Technology Data Exchange (ETDEWEB)

    Presto, A.A.; Granite, E.J


    The use of noble metals as catalysts for mercury oxidation in flue gas remains an area of active study. To date, field studies have focused on gold and palladium catalysts installed at pilot scale. In this article, we introduce bench-scale experimental results for gold, palladium and platinum catalysts tested in realistic simulated flue gas. Our initial results reveal some intriguing characteristics of catalytic mercury oxidation and provide insight for future research into this potentially important process.

  15. Platinum contamination issues in ferroelectric memories (United States)

    Boubekeur, H.; Mikolajick, T.; Pamler, W.; Hopfner, J.; Frey, L.; Ryssel, H.


    The contamination risk of processing with platinum electrodes on device performance in ferroelectric memories is assessed in this work. Details of platinum diffusion to the active regions at annealing temperatures of 800 degC are investigated by secondary ion mass spectroscopy, deep level transient spectroscopy, and Rutherford backscattering spectrometry techniques. Cross sectional transmission electron microscopy and local elemental analysis by energy dispersive x-ray spectroscopy were used to examine the precipitation of Pt in defect free silicon as an eventual cause of gate oxide degradation. The impact of platinum contamination on device performance is evaluated under the typical ferroelectric memory processing conditions. Results from leakage current and charge to breakdown measurements of intentionally contaminated diode and metal-oxide-semiconductor (MOS) structures, respectively, are presented. The results show that the degradation depends strongly on device design and configuration. A phosphorus doped polysilicon plug, which has the function of connecting the select transistor to the capacitor module, provides effective gettering regions and prevents the diffusion of Pt atoms to the active regions. Under typical processing conditions, no evident Pt precipitates were observed and up to a concentration level of 4 x1014 atoms/cm2, the leakage current of intentionally contaminated diodes does not increase, if the contamination occurs after front-end phosphorus doped poly-Si processing. Results from constant current charge to breakdown show a small number of breakdown events due to redeposition of Pt at the periphery of the MOS structure. The risk of processing with Pt electrodes in ferroelectric memories requires great care. Precautions like sealing the back surface and incorporating phosphorus doped polysilicon as the plug material are necessary to avoid the detrimental effects of Pt.

  16. Platinum-induced neurotoxicity: A review of possible mechanisms. (United States)

    Kanat, Ozkan; Ertas, Hulya; Caner, Burcu


    Patients treated with platinum-based chemotherapy frequently experience neurotoxic symptoms, which may lead to premature discontinuation of therapy. Despite discontinuation of platinum drugs, these symptoms can persist over a long period of time. Cisplatin and oxaliplatin, among all platinum drugs, have significant neurotoxic potential. A distal dose-dependent symmetrical sensory neuropathy is the most common presentation of platinum neurotoxicity. DNA damage-induced apoptosis of dorsal root ganglion (DRG) neurons seems to be the principal cause of neurological symptoms. However, DRG injury alone cannot explain some unique symptoms such as cold-aggravated burning pain affecting distal extremities that is observed with oxaliplatin administration. In this article, we briefly reviewed potential mechanisms for the development of platinum drugs-associated neurological manifestations.

  17. Preparation, characterization, and antitumor activity of new ethylenediamine platinum(IV) complexes containing mixed carboxylate ligands. (United States)

    Khokhar, A R; Deng, Y; Kido, Y; Siddik, Z H


    A series of ethylenediamine platinum(IV) complexes of the type PtIV(en)XA2 and PtIV(en)X'2A2, where X = 1,1-cyclobutanedicarboxylato or malonato, X' = chloro, cyclobutanecarboxylato, cyclopentanecarboxylato, or cyclohexanecarboxylato, and A = acetato or trifluoroacetato were synthesized and characterized by elemental analysis, infrared, and NMR (13C and 195Pt) spectroscopic techniques. These compounds had good to excellent antitumor activity against murine leukemia L1210 cells. Complexes with axial trifluoroacetate groups were superior to those with acetate ligands. Those possessing both axial trifluoroacetate groups and monodentate bis-carboxylate ligands in the equatorial positions were the most active in the series investigated.

  18. Preparation of Dispersed Platinum Nanoparticles on a Carbon Nanostructured Surface Using Supercritical Fluid Chemical Deposition

    Directory of Open Access Journals (Sweden)

    Mineo Hiramatsu


    Full Text Available We have developed a method of forming platinum (Pt nanoparticles using a metal organic chemical fluid deposition (MOCFD process employing a supercritical fluid (SCF, and have demonstrated the synthesis of dispersed Pt nanoparticles on the surfaces of carbon nanowalls (CNWs, two-dimensional carbon nanostructures, and carbon nanotubes (CNTs. By using SCF-MOCFD with supercritical carbon dioxide as a solvent of metal-organic compounds, highly dispersed Pt nanoparticles of 2 nm diameter were deposited on the entire surface of CNWs and CNTs. The SCF-MOCFD process proved to be effective for the synthesis of Pt nanoparticles on the entire surface of intricate carbon nanostructures with narrow interspaces.

  19. Structure-spectroscopic property relationships in a series of platinum acetylides (United States)

    Cooper, Thomas M.; Haley, Joy E.; Krein, Douglas M.; Burke, Aaron R.; Slagle, Jonathan E.


    In order to understand electronic and conformational effects on structure-spectroscopic property relationships in platinum acetylides, we synthesized a model series of chromophores trans-Pt(PBu3)2(C-CPhenyl-X)2, where X = NH2, OCH3, diphenylamino, t-Bu, methyl, H, F, benzothiazole, trifluoromethyl, CN and nitro. We collected linear spectra, including ground state absorption, phosphorescence and phosphorescence excitation spectra. We also performed DFT and TDDFT calculations on the ground and excited state properties of these compounds. The calculations and experimental data show the excited state properties are a function of the electronic properties of the substituents and the molecular conformation.

  20. Impact of the equatorial coordination sphere on the rate of reduction, lipophilicity and cytotoxic activity of platinum(IV) complexes. (United States)

    Höfer, Doris; Varbanov, Hristo P; Hejl, Michaela; Jakupec, Michael A; Roller, Alexander; Galanski, Markus; Keppler, Bernhard K


    The impact of the equatorial coordination sphere on the reduction behavior (i.e. rate of reduction) of platinum(IV) complexes with axial carboxylato ligands was studied. Moreover, the influence of equatorial ligands on the stability, lipophilicity and cytotoxicity of platinum(IV) compounds was evaluated. For this purpose, a series of platinum(IV) complexes featuring axial carboxylato ligands (succinic acid monoesters) was synthesized; anionic carboxylato (OAc(-), oxalate) and halido (Cl(-), Br(-), I(-)) ligands served as leaving groups and am(m)ine carrier ligands were provided by monodentately (isopropylamine, ammine+cyclohexaneamine) or bidentately (ethane-1,2-diamine) coordinating am(m)ines. All platinum(IV) products were fully characterized based on elemental analysis, high resolution mass spectrometry and multinuclear ((1)H, (13)C, (15)N, (195)Pt) NMR spectroscopy as well as by X-ray diffraction in some cases. The rate of reduction in the presence of ascorbic acid was determined by NMR spectroscopy and the lipophilicity of the complexes was investigated by analytical reversed phase HPLC measurements. Cytotoxic properties were studied by means of a colorimetric microculture assay in three human cancer cell lines derived from cisplatin sensitive ovarian teratocarcinoma (CH1/PA-1) as well as cisplatin insensitive colon carcinoma (SW480) and non-small cell lung cancer (A549). Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Fast cleavage of a diselenide induced by a platinum(II)-methionine complex and its biological implications. (United States)

    Liu, Qin; Wang, Xiaoyong; Yang, Xiaoliang; Liang, Xiao; Guo, Zijian


    Platinum-based anticancer drugs such as cisplatin induce increased oxidative stress and oxidative damage of DNA and other cellular components, while selenium plays an important role in the antioxidant defense system. In this study, the interaction between a platinum(II) methionine (Met) complex [Pt(Met)Cl(2)] and a diselenide compound selenocystine [(Sec)(2)] was studied by electrospray ionization mass spectrometry, high performance liquid chromatography mass spectrometry, and (1)H NMR spectroscopy. The results demonstrate that the diselenide bond in (Sec)(2) can readily and quickly be cleaved by the platinum complex. Formation of the selenocysteine (Sec) bridged dinuclear complex [Pt(2)(Met-S,N)(2)(μ-Sec-Se,Cl)](3+) and Sec chelated species [Pt(Met-S,N)(Sec-Se,N)](2+) was identified at neutral and acidic media, which seems to result from the intermediate [Pt(Met-S,N)(Sec-Se)Cl](+). An accelerated formation of S-Se and S-S bonds was also observed when (Sec)(2) reacted with excessive glutathione in the presence of [Pt(Met)Cl(2)]. These results imply that the mechanism of activity and toxicity of platinum drugs may be related to their fast reaction with seleno-containing biomolecules, and the chemoprotective property of selenium agents against cisplatin-induced toxicity could also be connected with such reactions.

  2. Synthesis, characterization and antimicrobial activity of novel platinum(IV) and palladium(II) complexes with meso-1,2-diphenyl-ethylenediamine-N,N‧-di-3-propanoic acid - Crystal structure of H2-1,2-dpheddp·2HCl·H2O (United States)

    Radić, Gordana P.; Glođović, Verica V.; Ratković, Zoran R.; Novaković, Slađana B.; Garcia-Granda, Santiago; Roces, Laura; Menéndez-Taboada, Laura; Radojević, Ivana D.; Stefanović, Olgica D.; Čomić, Ljiljana R.; Trifunović, Srećko R.


    In the reaction of meso-1,2-diphenyl-ethylenediamine (1,2-dphen) with neutralized 3-chlor-propanoic acid, the new linear tetradentate edda-like ligand (edda = ethylenediamine-N,N'-diacetic ion) meso-1,2-diphenyl-ethylenediamine-N,N'-di-3-propanoic acid dihydrochloride monohydrate (H2-1,2-dpheddp·2HCl·H2O) was prepared. The corresponding platinum(IV) complex, s-cis-dichlorido-(meso-1,2-diphenyl-ethylenediamine-N,N'-di-3-propanoate)-platinum(IV) ([PtCl2(1,2-dpheddp)]) was synthesized by heating potassium-hexachloridoplatinate(IV) and H2-1,2-dpheddp·2HCl·H2O on steam bath for 12 h with neutralization by means of lithium-hydroxide. The palladium(II) complex, cis-dichlorido-(meso-1,2-diphenyl-ethylenediamine-N,N'-di-3-propanoate)-palladium(II) ([PdCl2(1,2-dpheddp)]) was obtained in the similar way using potassium-tetrachloridopalladate(II), H2-1,2-dpheddp·2HCl·H2O and lithium-hydroxide. The compounds were characterized by elemental analysis and infrared spectroscopy. The spectroscopically predicted structure of the synthesized tetradentate ligand was confirmed by X-ray analysis of the H2-1,2-dpheddp·2HCl·H2O. Antimicrobial activity of the ligand and corresponding palladium(II) and platinum(IV) complexes is investigated against 25 species of microorganisms. Testing is preformed by microdilution method and minimum inhibitory concentrations (MIC) and minimum microbicidal concentration (MMC) have been determined. The difference between antimicrobial activity of the ligand and corresponding platinum(IV) and palladium(II) complex is noticed and, in general, palladium(II) complex was the most active.

  3. Using "Saccharomyces cerevisiae" to Test the Mutagenicity of Household Compounds: An Open Ended Hypothesis-Driven Teaching Lab (United States)

    Marshall, Pamela A.


    In our Fundamentals of Genetics lab, students perform a wide variety of labs to reinforce and extend the topics covered in lecture. I developed an active-learning lab to augment the lecture topic of mutagenesis. In this lab exercise, students determine if a compound they bring from home is a mutagen. Students are required to read extensive…

  4. 复方碘化钾滴眼液无菌检查方法的验证%Validation of sterility test of compound potassium iodide eye drops

    Institute of Scientific and Technical Information of China (English)

    余晓霞; 邱凯锋; 廖庆权


    目的:建立复方碘化钾滴眼液无菌检查方法。方法按《中国药典》2010年版二部无菌检查法中薄膜过滤法对复方碘化钾滴眼液的无菌检查方法进行验证。结果该制剂的无菌检查选用薄膜过滤法,以金黄色葡萄球菌为阳性对照菌,冲洗总量100 ml。结论经方法学验证,该法可行,结果可靠。%ObjectiveTo establish the method of sterility test of compound potassium iodide eye drops. MethodsAccording to sterility test in the appendix ofChinese Pharmacopoeia 2010 (section 2), the membrane filteration used in the sterility test of compound potassium iodide eye drops was validated.ResultsThe membrane filteration was used in the sterility test of compound potassium iodide eye drops, and staphylococcus aureus was used as positive control germs and the total amount of irrigation fluid was 100 ml.Conclusion Through the technological validation, the method is applicable and the result is reliable.

  5. Metals and metal compounds in cancer treatment. (United States)

    Desoize, Bernard


    Metals and metal compounds have been used in medicine for several thousands of years. In this review we summarized the anti-cancer activities of the ten most active metals: arsenic, antimony, bismuth, gold, vanadium, iron, rhodium, titanium, gallium and platinum. The first reviewed metal, arsenic, presents the anomaly of displaying anti-cancer and oncogenic properties simultaneously. Some antimony derivatives, such as Sb2O3, salt (tartrate) and organic compounds, show interesting results. Bismuth directly affects Helicobacter pylori and gastric lymphoma; the effects of bismuth complexes of 6-mercaptopurine are promising. Gold(I) and (III) compounds show anti-tumour activities, although toxicity remains high. Research into the potential use of gold derivatives is still ongoing. Several derivatives of vanadium show anti-proliferative activity, but their toxicity must be overcome. Several pieces of evidence indicate that iron deprivation could be an excellent therapeutic approach; furthermore, it is synergistic with classic anti-cancer drugs. Rhodium belongs to the same group as platinum and it also presents interesting activity, but with the same nephrotoxicity. Several rhodium compounds have entered phase I clinical trials. In contrast to the platinum complexes, titanium derivatives showed no evidence of nephrotoxicity or myelotoxicity; titanocene dichloride is undergoing clinical trial. The anti-proliferative effect of gallium could be related to its competition with the iron atom; in addition a derivative appears to reverse the multidrug resistance. The last metal reviewed, platinum, has given some of the very best anti-cancer drugs. Four derivatives are used today in the clinic; their mechanism of action and of resistance are described.

  6. Elaboration, physical and electrochemical characterizations of CO tolerant PEMFC anode materials. Study of platinum-molybdenum and platinum-tungsten alloys and composites; Elaborations et caracterisations electrochimiques et physiques de materiaux d'anode de PEMFC peu sensibles a l'empoisonnement par CO: etude d'alliages et de composites a base de platine-molybdene et de platine-tungstene

    Energy Technology Data Exchange (ETDEWEB)

    Peyrelade, E.


    PEMFC development is hindered by the CO poisoning ability of the anode platinum catalyst. It has been previously shown that the oxidation potential of carbon monoxide adsorbed on the platinum atoms can be lowered using specific Pt based catalysts, either metallic alloys or composites. The objective is then to realize a catalyst for which the CO oxidation is compatible with the working potential of a PEMFC anode. In our approach, to enhance the CO tolerance of platinum based catalyst supported on carbon, we studied platinum-tungsten and platinum-molybdenum alloys and platinum-metal oxide materials (Pt-WO{sub x} and Pt-MoO{sub x}). The platinum based alloys demonstrate a small effect of the second metal towards the oxidation of carbon monoxide. The platinum composites show a better tolerance to carbon monoxide. Electrochemical studies on both Pt-MoO{sub x} and Pt-WO{sub x} demonstrate the ability of the metal-oxides to promote the ability of Pt to oxidize CO at low potentials. However, chrono-amperometric tests reveal a bigger influence of the tungsten oxide. Complex chemistry reactions on the molybdenum oxide surface make it more difficult to observe. (author)

  7. Synthesis, characterization and electrochemical studies of novel platinum-based nanomaterials (United States)

    Wang, Jingpeng


    Platinum (Pt) as well as its alloys represent some of the most efficient catalyst materials among intermetallic compounds and alloys. An important clue throughout this work is the development of a desired synthetic approach of Pt-based nanomaterials---a one-step hydrothermal co-reduction of inorganic metal precursors. Slight modifications in experimental conditions have led to the production of Pt-based nanostructured materials with two distinct morphologies: (i) three-dimensional (3D) nanoporous Pt-M networks (M= Ru, Ir, Pb, Pd) when formaldehyde is used as a reducing agent; and (ii) 3D intermetallic Pt-M nanodendrites (M= Au, Pb, Bi or Pd) when formate ligands are present as multi-functional reagents in the hydrothermal process. Those as-synthesized Pt-based nanoporous catalysts not only possess significantly high surface areas, but also exhibit superb electrocatalytic activities towards the electrochemical oxidation of methanol and formic acid. Among them, the nanoporous PtPb networks were further tested towards the electro-oxidation of glucose. Voltammetric and amperometric results demonstrate that the PtPb electrodes have strong and sensitive current responses to the incremental glucose concentrations, and are capable of sensing glucose with excellent selectivity in neutral media. In the case of synthesizing Pt-based nanodendritic materials, ammonium formate and formic acid were used as multi-functional reagents in the hydrothermal-assisted fabrication of alloyed PtAu and PtPb nanodendrites, respectively. Electrochemical studies reveal that both PtAu and PtPb nanodendrites exhibit exceptionally high electrocatalytic activities in formic acid oxidation owing to their unique alloyed intermetallic crystal structures. The proposed coordination and co-reduction alloying mechanism together with the foreign particle-induced dendritic growth mechanism have been further proved to be universal for fabricating a wide range of intermetallic nanodendrites, including

  8. Electrochemical characterization of platinum nanoparticles stabilized by amines

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez-Meneses, E., E-mail: [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, CICATA-IPN Unidad Altamira, Km 14.5 Carretera Tampico-Puerto Industrial, C.P. 89600 Altamira, Tamaulipas (Mexico); Dominguez-Crespo, M.A. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, CICATA-IPN Unidad Altamira, Km 14.5 Carretera Tampico-Puerto Industrial, C.P. 89600 Altamira, Tamaulipas (Mexico); Montiel-Palma, V. [Centro de Investigaciones Quimicas, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001, Colonia Chamilpa, C.P. 62201 Cuernavaca, Morelos (Mexico); Chavez-Herrera, V.H. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, CICATA-IPN Unidad Altamira, Km 14.5 Carretera Tampico-Puerto Industrial, C.P. 89600 Altamira, Tamaulipas (Mexico); Gomez, E. [Instituto de Quimica-Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, C.P. 04510 Mexico, D.F. (Mexico); Hernandez-Tapia, G. [Gerencia de Catalizadores y Proceso, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas norte 152, 07730 Mexico, D.F. (Mexico)


    In this work we present the synthesis by Chaudret approach of Pt nanoparticles stabilized by primary amine (-NH{sub 2}) compounds. Their electrochemical performance as cathodes in low temperature polymer electrolite fuel cells on the oxygen reduction reaction (ORR) is also presented. Transmission electron microscopy (TEM) images of the samples show Pt nanostructures with particle size varying from 10 to 100 nm depending on the kind of the stabilizer used during the catalyst preparation. In some cases well-dispersed isolated platinum nanoparticles were observed. The activity of the dispersed catalysts (Pt/C) with respect to the ORR was investigated using steady state polarization measurements. The kinetic parameters showed that although no significant differences between the Tafel slopes of the Pt catalysts exist, transfer coefficients and exchange current densities show higher activities when the Pt nanoparticles were stabilized by tert-butylamine (TBA). The performance with respect to the ORR of the Pt/C catalyst on vulcan carbon substrate is active and comparable to that reported in the literature for state-of-art electrocatalysts.

  9. Modification of the sulphur resistance of platinum by addition of metals for aromatics hydrogenation; Modification de la thioresistance du platine par ajouts d'elements metalliques pour l'hydrogenation d'aromatiques

    Energy Technology Data Exchange (ETDEWEB)

    Guillon, E.


    The aim of this study is based on the understanding of sulphur resistance of platinum catalytic systems. In this work, bimetallic systems (Pt-Ge, Pt-Au and Pt-Pd) supported on {gamma}-alumina have been studied. Preparation methods have been chosen to give the best control of the physicochemical properties of final system. Electronic and geometrical properties of the metallic phase were characterised by various techniques (TPR, infrared spectroscopy of adsorbed CO (IR(CO)), EXAFS, LEIS). Ortho-xylene hydrogenation in presence of 100 ppm of sulphur was used as model catalytic test in order to study the sulphur resistance of the catalysts. It has been shown that germanium and palladium act as electro-acceptors toward platinum. The ranking of catalytic activity in presence of sulphur is as followed: Pt-Pd > Pt-Au {approx_equal} Pt >> Pt-Ge {approx_equal} 0. The best sulphur resistance for Pt-Pd was obtained for the composition Pt{sub 20}Pd{sub 80} (Pd/Pt=4). An eggshell PdS structure with Pt (sulfur free) core is proposed. These works show that the sulphur resistance of platinum is not only linked with its electronic properties. They allow us to propose an original concept of sulphur resistant catalyst taking into account each catalytic parameters such as chemical bonding of S and aromatic compounds on the metallic site, physico-chemical characteristics of the bimetallic aggregates (particle size, structure, surface composition) and electronic modification of surface atoms in bimetallic catalysts. (author)

  10. Processes influencing migration of bioavailable organic compounds from polymers - investigated during biotic and abiotic testing under static and non-static conditions with varying S/V-ratios

    DEFF Research Database (Denmark)

    Corfitzen, Charlotte B.; Arvin, Erik; Albrechtsen, Hans-Jørgen

    The migration of bioavailable organic compounds (‘bioavailable migration’) from polymeric materials used for drinking water distribution was investigated by an abiotic test: Extracting materials under sterile conditions, and a biotic test: Extracting materials in presence of bacteria. Both tests...... showed elevated bioavailable migration during the first two weeks of incubation followed by a lower constant level, which was maintained during the test period of 16 weeks. Problems with aftergrowth due to bioavailable migration from polymeric materials are therefore not solved by initial flushing....../V-ratios had any effect on the bioavailable migration in the biotic tests. Not to underestimate growth potential of polymers, investigations should thus be performed in the presence of a diverse microbial population with paired measurements of biomass in the water phase and on the material surfaces....

  11. Correlation of rs1799793 polymorphism in ERCC2 and the clinical response to platinum-based chemotherapy in patients with triple negative breast cancer. (United States)

    Lu, Jun; Zhao, Haitao; Li, Sha; Tian, Zhongze; Zhu, Xianghui; Wang, Hongyi; Fu, Hua


    Polymorphisms of DNA repair genes may affect the repair capacity of DNA damages and cause different responses towards chemotherapy. Excision repair cross-complementing group 2 (ERCC2) plays an important role in the nucleotide excision repair. The aim of this study was to investigate the association between ERCC2 single nucleotide polymorphisms (SNPs) and the response to platinum-based chemotherapy among patients with triple negative breast cancer. In total, 60 triple negative breast cancer patients treated with platinum-based chemotherapy were studied. The clinical, pathological and treatment data of them were collected. Sequenom's MassARRAY system was used in the detection of the SNPs of ERCC2. Finally, the association between genotypes and different clinical responses among patients was analyzed. All of the patients received a platinum-based chemotherapy for 4 cycles in median and achieved an overall response rate of 66.7%, showing a comparative good response towards platinum-based chemotherapy among triple negative breast cancer. Fifty-three of the 60 patients had got the results of ERCC2 rs1799793 polymorphisms after MassARRAY detection. The proportion of GG genotype and GA genotype was 81.1% and 18.9% respectively. The response rate of the rs1799793 GG genotype group was 69.8%, while the GA genotype group only had a response rate of 30.0%. It turned out that the GG genotype was associated with better response towards platinum-based chemotherapy (P=0.030). ERCC2 rs1799793 polymorphism may be associated with the clinical sensitivity of platinum-based chemotherapy and could be a potential predictive biomarker for triple negative breast cancer patients treated with platinum compounds.

  12. From the Test Tube to the Treatment Room: Fundamentals of Boron-containing Compounds and their Relevance to Dermatology


    Del Rosso, James Q.; Jacob J Plattner


    The development of new drug classes and novel molecules that are brought to the marketplace has been a formidable challenge, especially for dermatologic drugs. The relative absence of new classes of antimicrobial agents is also readily apparent. Several barriers account for slow drug development, including regulatory changes, added study requirements, commercial pressures to bring drugs to market quickly by developing new generations of established compounds, and the greater potential for fai...

  13. Quasi-homogeneous hydrogenation with platinum and palladium nanoparticles stabilized by dendritic core-multishell architectures. (United States)

    Schwarze, Michael; Keilitz, Juliane; Nowag, Sabrina; Parapat, Riny Y; Haag, Rainer; Schomäcker, Reinhard


    Platinum and palladium nanoparticles, supported and stabilized by polymeric core-shell architectures, proved to be active catalysts for hydrogenation reactions. Here, two different reactions were used as probes to investigate the influence of the polymeric support: the hydrogenation of α-methyl styrene (AMS) to cumene and the partial hydrogenation of 1,5-cyclooctadiene (COD). We found that the stability of the nanoparticles and the rate of reaction are higher in the presence of a hydrophobic octadecyl shell within a three-shell polymer system. The kinetic study of AMS hydrogenation showed much higher activities for palladium nanoparticles than for platinum nanoparticles, and the obtained results (e.g., 35 kJ/mol for the activation energy) are of the same order of magnitude as reported earlier for palladium supported on alumina. A methanol/n-heptane biphasic mixture was tested for catalyst recycling and allowed for highly efficient catalyst separation with very low metal leaching.

  14. Chlorine sensing properties of zinc oxide resistive gas sensor doped with platinum (United States)

    Fiedot, M.; Suchorska-Woźniak, P.; Rac, O.; Nawrot, W.; Teterycz, H.


    In presented studies resistive chlorine gas sensor with gas sensitive layer in the form of zinc oxide microrods doped with platinum was developed. The growth of active layer was carried out in water solution containing zinc nitrate (V), hexamethylenetetramine and chloroplatinic acid using the chemical bath deposition method. The structure and morphology of obtained sensors was characterized by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX). To determine the chlorine gas sensing properties Temperature-Stimulated Conductance method (TSC) was used. During the measurements sensor was tested in a reference atmosphere and an atmosphere with 2, 5 or 8 ppm of chlorine. Obtained results have shown that zinc oxide microrods doped with platinum were obtained. TSC measurements showed that developed sensor allows to detect chlorine with very good sensitivity.

  15. Surface features and catalytic performance of platinum/alumina catalysts in slurry-phase hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez-Ortiz, M.A.; Gonzalez-Marcos, M.P.; Arnaiz-Aguilar, S.; Gonzalez-Marcos, J.A.; Gonzalez-Velasco, J.R. (Univ. del Pais Vasco/Euskal Hirrika Unibertsitatea, Bilbao (Spain). Dept. de Ingenierlla Quimica)


    Several platinum catalysts supported on three commercial [gamma]-aluminas were prepared by impregnation and anionic exchange using aqueous solutions of H[sub 2]PtCl[sub 6]. A number of methods were used to characterize the precursors as well as the final catalysts, including TGA, TPR, and hydrogen chemisorption at 298 K. TPR measurements showed two reduction peaks for the catalysts: the first one corresponding to reduction of the metal precursor to platinum and the second one associated to formation of a surface complex, Pt-Al[sub 2]O[sub 3[minus]x], With partial reduction of the support. The activity of the different catalysts was tested in the slurry-phase hydrogenation of benzene. The results obtained in the activity measurements have been correlated to the characteristics of the catalysts.

  16. DNA compaction by mononuclear platinum cancer drug cisplatin and the trisplatinum anticancer agent BBR3464: Differences and similarities. (United States)

    Banerjee, T; Dubey, P; Mukhopadhyay, R


    Cisplatin, a mononuclear platinum compound, which is known as a cancer drug for long time, can exhibit considerable side effects and is also not effective in many types of cancer. Therefore, the alternative platinum anticancer agents that can act at a much lower dose limit compared to the dose relevant for cisplatin treatment have been searched for. BBR3464, a trinuclear platinum compound, is found to exhibit cytotoxic effects at 10 to 1000 times lower dose limit, even in cisplatin-resistant cancer cells. The primary cellular target for cisplatin and BBR3464 is thought to be DNA. Herein, we report the nature of DNA structural changes that are induced by cisplatin and BBR3464, considering the same DNA sequence and similar sample deposition methods for comparison purpose. We have applied high-resolution atomic force microscopy (AFM) in order to obtain an idea about the molecular basis of BBR3464's effectiveness at the lower dose limit. We show from the molecularly resolved AFM images that both the compounds can compact the whole dsDNA molecules, though the degree of compaction in case of BBR3464 treatment is significantly higher. Furthermore, local compaction in terms of loop structure formation could be induced by both BBR3464 and cisplatin, though BBR3464 generated microloops and macroloops both, whereas cisplatin could generate primarily the microloops. It is a significant observation that BBR3464 could induce relatively drastic DNA structural changes in terms of loop formation as well as overall DNA compaction at a molar ratio, which is 50 times less than that applied for cisplatin treatment. Implications of such structural changes in cytotoxic effects of the platinum anticancer agents will be mentioned.

  17. Environmental and biological monitoring of platinum-containing drugs in two hospital pharmacies using positive air pressure isolators. (United States)

    Kopp, Bettina; Crauste-Manciet, Sylvie; Guibert, Agnès; Mourier, Wilhelmine; Guerrault-Moro, Marie-Noelle; Ferrari, Sylvie; Jomier, Jean-Yves; Brossard, Denis; Schierl, Rudolf


    Environmental and biological monitoring of platinum containing drugs was implemented in two French hospital pharmacies using positive air pressure isolators and having similar working procedures when preparing antineoplastic drugs. Wipe sampling of surfaces, gloves, and vials was performed in the preparation room and in storage areas. All employees involved in the preparation of antineoplastic drugs were tested for urinary platinum on Monday before work and Friday after shift. Only traces of platinum were detected on surfaces in the preparation room outside the isolators (less than 1.61 pg cm(-2)). However, in one center, significant contamination was found in the storage area of the drug vials, which can most likely be linked to the rupture of a platinum vial and due to inefficient cleaning procedures. Surfaces inside the isolators were found to be contaminated (maximum: 198.4 pg cm(-2)). A higher level of contamination was detected in one pharmacy and could be explained by the lack of overgloving with regular changes during the preparation process. Nitrile gloves used during drug handling outside the isolator showed the highest platinum concentration (maximum: 5.86 ng per pair). With regards to platinum urine concentration, no significant difference was found between exposed and unexposed pharmacy personnel. Isolator technology combined with individual protective measures seems to be efficient to protect workers from occupational exposure to antineoplastic drugs, whereas specific individual protective procedures implemented were focussing on the risk of handling vials outside the isolator (e.g. high frequency of glove changing). Moreover, overgloving inside the isolator would contribute to substantially decrease inner surface contamination and should be recommended in order to limit the transfer of chemical contamination to the end products.

  18. Surface Analysis of 4-Aminothiophenol Adsorption at Polycrystalline Platinum Electrodes (United States)

    Rosario-Castro, Belinda I.; Fachini, Estevao R.; Contes, Enid J.; Perez-Davis, Marla E.; Cabrera, Carlos R.


    Formation of self-assembled monolayer (SAM) of 4-aminothiophenol (4-ATP) on polycrystalline platinum electrodes has been studied by surface analysis and electrochemistry techniques. The 4-ATP monolayer was characterized by cyclic voltammetry (CV), Raman spectroscopy, reflection absorption infrared (RAIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV) experiments give an idea about the packing quality of the monolayer. RAIR and Raman spectra for 4-ATP modified platinum electrodes showed the characteristic adsorption bands for neat 4-ATP indicating the adsorption of 4-ATP molecules on platinum surface. The adsorption on platinum was also evidenced by the presence of sulfur and nitrogen peaks by XPS survey spectra of the modified platinum electrodes. High resolution XPS studies and RAIR spectrum for platinum electrodes modified with 4-ATP indicate that molecules are sulfur-bonded to the platinum surface. The formation of S-Pt bond suggests that ATP adsorption gives up an amino terminated SAM. Thickness of the monolayer was evaluated via angle-resolved XPS (AR-XPS) analyses. Derivatization of 4-ATP SAM was performed using 16-Br hexadecanoic acid.

  19. Compound-specific effects of diverse neurodevelopmental toxicants on global gene expression in the neural embryonic stem cell test (ESTn)

    NARCIS (Netherlands)

    Theunissen, P.T.; Robinson, J.F.; Pennings, J.L.A.; van Herwijnen, M.; Kleinjans, J.C.S.; Piersma, A.H.


    Alternative assays for developmental toxicity testing are needed to reduce animal use in regulatory toxicology. The in vitro murine neural embryonic stem cell test (ESTn) was designed as an alternative for neurodevelopmental toxicity testing. The integration of toxicogenomic-based approaches may fur

  20. A 155-plex High-Throughput In Vitro Coregulator Binding Assay for (Anti-) Estrogenicity Testing Evaluated with 23 Reference Compounds

    NARCIS (Netherlands)

    Wang, S.; Houtman, R.; Melchers, D.; Aarts, J.; Peijnenburg, A.A.C.M.; Beuningen, van R.; Rietjens, I.M.C.M.; Bovee, T.F.H.


    To further develop an integrated in vitro testing strategy for replacement of in vivo tests for (anti-)estrogenicity testing, the ligand-modulated interaction of coregulators with estrogen receptor a was assessed using a PamChip® plate. The relative estrogenic potencies determined, based on ERa bind

  1. Conjugated platinum(IV)-peptide complexes for targeting angiogenic tumor vasculature. (United States)

    Mukhopadhyay, Sumitra; Barnés, Carmen M; Haskel, Ariel; Short, Sarah M; Barnes, Katie R; Lippard, Stephen J


    The integrins alpha vbeta3 and alpha vbeta5 and the membrane-spanning surface protein aminopeptidase N (APN) are highly expressed in tumor-induced angiogenesis, making them attractive targets for therapeutic intervention. Both integrins and APN recognize a broad range of peptides containing RGD (Arg-Gly-Asp) and NGR (Asn-Gly-Arg) motifs, respectively. Here, we describe the design, synthesis, and characterization of a series of mono- and difunctionalized platinum(IV) complexes in which a conjugated peptide motif, containing RGD, (CRGDC)c, (RGDfK)c, or NGR, is appended as a "tumor-homing device" to target tumor endothelial cells selectively over healthy cells. Platinum(IV)-peptide complexes with nonspecific amino acids or peptide moieties were prepared as controls. Concentration-response curves of these compounds were evaluated against primary proliferating endothelial cells and tumor cell lines and compared to those of cisplatin, a well-described platinum-based chemotherapeutic agent. The Pt(IV)-RGD conjugates were highly and specifically cytotoxic to cell lines containing alpha vbeta3 and alpha vbeta5, approaching the activity of cisplatin. The Pt(IV)-NGR complexes were less active than Pt(IV)-RGD-containing compounds but more active than nonspecific Pt-peptide controls. Integrin alpha vbeta3 mediated, at least in part, the anti-proliferative effect of a Pt(IV)-RGD conjugate, as demonstrated by a decreased inhibitory response when endothelial cells were either (1) incubated with an excess of alpha vbeta3/alpha vbeta5-specific RGD pentapeptides or (2) transfected with RNAi for beta 3, but not beta 1, integrins. These results suggest a rational approach to improved chemotherapy with Pt(IV)-peptide conjugates by selective drug delivery to the tumor compartment.

  2. The role of the equatorial ligands for the redox behavior, mode of cellular accumulation and cytotoxicity of platinum(IV) prodrugs. (United States)

    Göschl, Simone; Varbanov, Hristo P; Theiner, Sarah; Jakupec, Michael A; Galanski, Markus; Keppler, Bernhard K


    The current study aims to elucidate the possible reasons for the significantly different pharmacological behavior of platinum(IV) complexes with cisplatin-, carboplatin- or nedaplatin-like cores and how this difference can be related to their main physicochemical properties. Chlorido-containing complexes are reduced fast (within hours) by ascorbate and are able to unwind plasmid DNA in the presence of ascorbate, while their tri- and tetracarboxylato analogs are generally inert under the same conditions. Comparison of the lipophilicity, cellular accumulation and cytotoxicity of the investigated platinum compounds revealed the necessity to define new structure-property/activity relationships (SPRs and SARs). The higher activity and improved accumulation of platinum(IV) complexes bearing Cl(-) in equatorial position cannot only be attributed to passive diffusion facilitated by their lipophilicity. Therefore, further platinum accumulation experiments under conditions where active/facilitated transport mechanisms are suppressed were performed. Under hypothermic conditions (4°C), accumulation of dichloridoplatinum(IV) complexes is reduced down to 10% of the amount determined at 37°C. These findings suggest the involvement of active and/or facilitated transport in cellular uptake of platinum(IV) complexes with a cisplatin-like core. Studies with ATP depletion mediated by oligomycin and low glucose partially confirmed these observations, but their feasibility was severely limited in the adherent cell culture setting. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Bio-inspired routes for synthesizing efficient nanoscale platinum electrocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Cha, Jennifer N. [Univ. of California, San Diego, CA (United States); Wang, Joseph [Univ. of California, San Diego, CA (United States)


    The overall objective of the proposed research is to use fundamental advances in bionanotechnology to design powerful platinum nanocrystal electrocatalysts for fuel cell applications. The new economically-viable, environmentally-friendly, bottom-up biochemical synthetic strategy will produce platinum nanocrystals with tailored size, shape and crystal orientation, hence leading to a maximum electrochemical reactivity. There are five specific aims to the proposed bio-inspired strategy for synthesizing efficient electrocatalytic platinum nanocrystals: (1) isolate peptides that both selectively bind particular crystal faces of platinum and promote the nucleation and growth of particular nanocrystal morphologies, (2) pattern nanoscale 2-dimensional arrays of platinum nucleating peptides from DNA scaffolds, (3) investigate the combined use of substrate patterned peptides and soluble peptides on nanocrystal morphology and growth (4) synthesize platinum crystals on planar and large-area carbon electrode supports, and (5) perform detailed characterization of the electrocatalytic behavior as a function of catalyst size, shape and morphology. Project Description and Impact: This bio-inspired collaborative research effort will address key challenges in designing powerful electrocatalysts for fuel cell applications by employing nucleic acid scaffolds in combination with peptides to perform specific, environmentally-friendly, simultaneous bottom-up biochemical synthesis and patterned assembly of highly uniform and efficient platinum nanocrystal catalysts. Bulk synthesis of nanoparticles usually produces a range of sizes, accessible catalytic sites, crystal morphologies, and orientations, all of which lead to inconsistent catalytic activities. In contrast, biological systems routinely demonstrate exquisite control over inorganic syntheses at neutral pH and ambient temperature and pressures. Because the orientation and arrangement of the templating biomolecules can be precisely

  4. The RSC Faraday prize lecture of 1989 on platinum. (United States)

    Thomas, John Meurig


    In 1861, Michael Faraday gave one of his last Friday Evening Discourses at the Royal Institution of Great Britain, London, on platinum, which he described as "this beautiful, magnificent and valuable metal". More than a hundred and twenty years later (in 1989), the author re-enacted, at the Royal Institution, many of the demonstrations that Faraday carried out in his memorable Discourse. This article outlines many of Faraday's views on, and experiments with, platinum. It also describes the continuing importance and utilization of platinum, both as perceived in 1989 and from present perspectives.

  5. Study of supported platinum catalysts by anomalous scattering

    Energy Technology Data Exchange (ETDEWEB)

    Georgopoulos, P.; Cohen, J.B.


    Platinum metal catalysts supported on silica gel and alumina were examined by wide-angle anomalous x-ray scattering at the Cornell High Energy Synchrotron Source. Complete removal of the support background features is achieved by this method, eliminating errors due to inaccurate background estimation. Platinum diffraction patterns from very-high-percentage metal-exposed catalysts were obtained for the first time, as well as from platinum supported on alumina. This technique is suitable for examining catalysts under working conditions and is superior to EXAFS for determinations of particle morphology and size distribution. 10 references, 8 figures.

  6. Interaction of novel bis(platinum) complexes with DNA.


    Roberts, J D; Van Houten, B; Qu, Y; Farrell, N P


    Bis(platinum) complexes [[cis-PtCl2(NH3)]2H2N(CH2)nNH2] are a novel series of potential anticancer agents in which two cis-diamine(platinum) groups are linked by an alkyldiamine of variable length. These complexes are potentially tetrafunctional, a unique feature in comparison with known anticancer agents. Studies of DNA interactions of bis(platinum) complexes in comparison with cisplatin demonstrate significant differences. Investigations of interstrand crosslink formation in which crosslink...

  7. Platinum(II) and platinum(IV) complexes stabilized by abnormal/mesoionic C4-bound dicarbenes. (United States)

    Khlebnikov, Vsevolod; Heckenroth, Marion; Müller-Bunz, Helge; Albrecht, Martin


    Platinum(II) complexes comprising abnormal diimidazolylidene ligands were synthesized from cis-PtMe(2)(DMSO)(2) using microwave-assisted double C-H bond activation. NMR analysis revealed an unusual solvolysis process, induced by coordinating solvents such as DMSO and MeCN, which has not been observed in related normal dicarbene complexes. NMR and IR spectroscopy and crystallographic analysis of the mono-substituted DMSO complex indicate a sulfur-bonding of the DMSO ligand to the platinum(II) center. Analysis of the DMSO exchange kinetics provided for the first time a quantitative measure of the trans effect of abnormal carbene ligands. The kinetic exchange rate in these bidentate abnormal dicarbene complexes is 0.050(±2) s(-1) and thus similar to analogous platinum(II) complexes containing phenylpyridine, yet significantly slower than that induced by pyridylidene pyridine. Reaction of the dicarbene platinum(II) complexes with PhICl(2), Br(2) and I(2) afforded the corresponding platinum(IV) complexes. Linkage isomerism of the Pt(IV)-bound DMSO was observed when the bromination reaction was performed in DMSO solution. Moreover, solvolysis was less pronounced in the platinum(IV) complexes than in the corresponding platinum(II) analogues.

  8. The electrooxidation mechanism of formic acid on platinum and on lead ad-atoms modified platinum studied with the kinetic isotope effect (United States)

    Bełtowska-Brzezinska, M.; Łuczak, T.; Stelmach, J.; Holze, R.


    Kinetics and mechanism of formic acid (FA) oxidation on platinum and upd-lead ad-atoms modified platinum electrodes have been studied using unlabelled and deuterated compounds. Poisoning of the electrode surface by CO-like species was prevented by suppression of dissociative chemisorption of FA due to a fast competitive underpotential deposition of lead ad-atoms on the Pt surface from an acidic solution containing Pb2+ cations. Modification of the Pt electrode with upd lead induced a catalytic effect in the direct electrooxidation of physisorbed FA to CO2. With increasing degree of H/D substitution, the rate of this reaction decreased in the order: HCOOH > DCOOH ≥ HCOOD > DCOOD. HCOOH was oxidized 8.5-times faster on a Pt/Pb electrode than DCOOD. This primary kinetic isotope effect proves that the C-H- and O-H-bonds are simultaneously cleaved in the rate determining step. A secondary kinetic isotope effect was found in the dissociative chemisorption of FA in the hydrogen adsorption-desorption range on a bare Pt electrode after H/D exchange in the C-H bond, wherein the influence of deuterium substitution in the O-H group was negligibly small. Thus the C-H bond cleavage is accompanied by the C-OH and not the O-H bond split in the FA decomposition, producing CO-like species on the Pt surface sites.

  9. Reference compounds for alternative test methods to indicate developmental neurotoxicity (DNT) potential of chemicals: example lists and criteria for their selection and use. (United States)

    Aschner, Michael; Ceccatelli, Sandra; Daneshian, Mardas; Fritsche, Ellen; Hasiwa, Nina; Hartung, Thomas; Hogberg, Helena T; Leist, Marcel; Li, Abby; Mundi, William R; Padilla, Stephanie; Piersma, Aldert H; Bal-Price, Anna; Seiler, Andrea; Westerink, Remco H; Zimmer, Bastian; Lein, Pamela J


    There is a paucity of information concerning the developmental neurotoxicity (DNT) hazard posed by industrial and environmental chemicals. New testing approaches will most likely be based on batteries of alternative and complementary (non-animal) tests. As DNT is assumed to result from the modulation of fundamental neurodevelopmental processes (such as neuronal differentiation, precursor cell migration or neuronal network formation) by chemicals, the first generation of alternative DNT tests target these processes. The advantage of such types of assays is that they capture toxicants with multiple targets and modes-of-action. Moreover, the processes modelled by the assays can be linked to toxicity endophenotypes, i.e., alterations in neural connectivity that form the basis for neurofunctional deficits in man. The authors of this review convened in a workshop to define criteria for the selection of positive/negative controls, to prepare recommendations on their use, and to initiate the setup of a directory of reference chemicals. For initial technical optimization of tests, a set of > 50 endpoint-specific control compounds was identified. For further test development, an additional "test" set of 33 chemicals considered to act directly as bona fide DNT toxicants is proposed, and each chemical is annotated to the extent it fulfills these criteria. A tabular compilation of the original literature used to select the test set chemicals provides information on statistical procedures, and toxic/non-toxic doses (both for pups and dams). Suggestions are provided on how to use the > 100 compounds (including negative controls) compiled here to address specificity, adversity and use of alternative test systems.

  10. The design, construction and testing of a microcombustion calorimeter suitable for organic compounds containing C, H and O

    Energy Technology Data Exchange (ETDEWEB)

    Davalos, Juan Z.; Roux, M. Victoria [CSIC, Lab. de Termoquimica, Madrid (Spain)


    To obtain reliable standard energies of combustion with small amounts of C, H, O compounds, a new microcombustion calorimetry system has been set up. The design, construction, calibration and measurement experiments are described. The system includes a commercial combustion bomb with an internal volume of 22 cm{sup 3}. Samples of around 80 mg are suitable if one wants to retain the same levels of accuracy and reproducibility as those in macrocombustion experiments. Calibration of the calorimeter was performed using benzoic acid. {delta} (Calorimeter) = 2083.74{+-}0.48JK{sup -1} was obtained. Combustion measurements using m-methoxybenzoic acid were made in order to verify the chemistry of the combustion process involved in the corresponding analysis of results and the accuracy of the measurement of combustion energy. The uncertainty of the results shows that the instrument described and the experimental procedure used for the determination of enthalpies of formation of compounds containing C, H and O provide a high reliability. (Author)

  11. Novel approaches to polynuclear platinum pro-drugs. Selective release of cytotoxic platinum-spermidine species through hydrolytic cleavage of carbamates. (United States)

    Hegmans, A; Qu, Y; Kelland, L R; Roberts, J D; Farrell, N


    BBR3464 is a novel trinuclear platinum drug currently in Phase II clinical trials. Polyamine-bridged dinuclear platinum compounds as represented by [[trans-Pt(NH(3))(2)Cl](2)-mu-spermidine-N(1),N(8)]Cl(3) (1) are highly interesting second-generation analogues of BBR3464 because the hydrogen-bonding and electrostatic contributions of the central platinum-amine group in BBR3464 are replicated by the free, noncoordinated "central" quaternary nitrogens of the linear polyamine linker while the presence of two separate Pt-Cl bonds maintains the bifunctional binding mode on the DNA adducts. Preclinical investigations confirm the potency of these species with cytotoxicity in the nanomolar range. This remarkable potency results in a relatively narrow therapeutic index. To enhance the therapeutic index of these drugs, we investigated the potential for "pro-drug" delivery of less toxic and better tolerated derivatives such as the compounds [[trans-Pt(NH(3))(2)Cl](2)-mu-N(4)-R-spermidine-N(1),N(8)]Cl(2) where N(4)-R represents BOC (tert-butyl), CBz (benzyl), and Fmoc (fluorenylmethyl) carbamate blocking groups, 2-4, respectively. The bulky Fmoc derivative showed evidence for conformational isomers by (1)H NMR spectroscopy due to the inequivalence of the two n-propyl and n-butyl side chains of the spermidine moiety. The rate constants for hydrolysis and release of 1 were calculated. Release of cytotoxic 1 at physiologically relevant pH followed the order 4 > 2 > 3. The calculated values for 4 (pH 5, 6.0(+/-3.9) x 10(-10) s(-1); pH 6, 6.5(+/-0.2) x 10(-9) s(-1); pH 7, 6.0(+/-0.2) x 10(-8) s(-1); pH 8, 1.6(+/-0.1) x 10(-7) s(-1)) show a more pronounced pH dependence compared to 2 (pH 5, 4.6(+/-0.1) x 10(-8) s(-1); pH 6, 4.2(+/-0.1) x 10(-8) s(-1); pH 7, 3.2(+/-0.1) x 10(-8) s(-1)). Preliminary biological assays of cellular uptake and cytotoxicity confirm the utility of the pro-drug concept. While blocked-polyamine compounds such as 2-4 are, in general, 2-3 orders of magnitude

  12. (Pt{sub 1–x}Cu{sub x}){sub 3}Cu{sub 2}B and Pt{sub 9}Cu{sub 3}B{sub 5}, the first examples of copper platinum borides. Observation of superconductivity in a novel boron filled β-Mn-type compound

    Energy Technology Data Exchange (ETDEWEB)

    Salamakha, Leonid P. [Institute of Solid State Physics, TU Wien, A-1040 Wien (Austria); Sologub, Oksana, E-mail: [Institute of Solid State Physics, TU Wien, A-1040 Wien (Austria); Stöger, Berthold [Institute of Chemical Technologies and Analytics, TU Wien, A-1040 Wien (Austria); Michor, Herwig; Bauer, Ernst [Institute of Solid State Physics, TU Wien, A-1040 Wien (Austria); Rogl, Peter F. [Institute of Physical Chemistry, University of Vienna, A-1090 Wien (Austria)


    New ternary copper platinum borides have been synthesized by arc melting of pure elements followed by annealing at 600 °C. The structures have been studied by X-ray single crystal and powder diffraction. (Pt{sub 1−x}Cu{sub x}){sub 3}Cu{sub 2}B (x=0.33) forms a B-filled β-Mn-type structure (space group P4{sub 1}32; a=0.6671(1) nm). Cu atoms are distributed preferentially on the 8c atom sites, whereas the 12d site is randomly occupied by Pt and Cu atoms (0.670(4) Pt±0.330(4) Cu). Boron is located in octahedral voids of the parent β-Mn-type structure. Pt{sub 9}Cu{sub 3}B{sub 5} (space group P-62m; a=0.9048(3) nm, c=0.2908(1) nm) adopts the Pt{sub 9}Zn{sub 3}B{sub 5–δ}-type structure. It has a columnar architecture along the short translation vector exhibiting three kinds of [Pt{sub 6}] trigonal prism columns (boron filled, boron semi-filled and empty) and Pt channels with a pentagonal cross section filled with Cu atoms. The striking structural feature is a [Pt{sub 6}] cluster in form of an empty trigonal prism at the origin of the unit cell, which is surrounded by coupled [BPt{sub 6}] and [Pt{sub 6}] trigonal prisms, rotated perpendicularly to the central one. There is no B–B contact as well as Cu–B contact in the structure. The relationships of Pt{sub 9}Cu{sub 3}B{sub 5} structure with the structure of Ti{sub 1+x}Os{sub 2−x}RuB{sub 2} as well as with the structure families of metal sulfides and aluminides have been elucidated. (Pt{sub 1–x}Cu{sub x}){sub 3}Cu{sub 2}B (x=0.3) (B-filled β-Mn-type structure) is a bulk superconductor with a transition temperature of about 2.06 K and an upper critical field μ{sub 0}H{sub C2}(0){sup WHH} of 1.2 T, whereas no superconducting transition has been observed up to 0.3 K in Pt{sub 9}Cu{sub 3}B{sub 5} (Pt{sub 9}Zn{sub 3}B{sub 5–δ}-type structure) from electrical resistivity measurements. - Highlights: • First two copper platinum borides, (Pt{sub 0.67}Cu{sub 0.33}){sub 3}Cu{sub 2}B and Pt{sub 9}Cu{sub 3}B

  13. Tetracarboxylatoplatinum(IV) complexes featuring monodentate leaving groups - A rational approach toward exploiting the platinum(IV) prodrug strategy. (United States)

    Höfer, Doris; Varbanov, Hristo P; Legin, Anton; Jakupec, Michael A; Roller, Alexander; Galanski, Markus; Keppler, Bernhard K


    A series of novel symmetrically and unsymmetrically coordinated platinum(IV) complexes with monodentate carboxylato ligands was synthesized. The compounds exhibit a general coordination sphere of [Pt(en)(OCOR)2(OCOR')(OCOR″)], where the carboxylato ligands are represented by acetato and succinic acid monoester ligands. Dicarboxylatoplatinum(II) complexes were synthesized and oxidized symmetrically or unsymmetrically to obtain platinum(IV) complexes, which were subsequently carboxylated with noncyclic anhydrides. The compounds were investigated in detail by elemental analysis, mass spectrometry, infrared and multinuclear ((1)H, (13)C, (15)N, (195)Pt) NMR spectroscopy as well as by X-ray diffraction in some cases. The reduction behavior was followed by NMR spectroscopy, while stability and lipophilicity were examined by analytical reversed phase HPLC measurements. Cytotoxic properties were studied in three human cancer cell lines derived from cisplatin sensitive ovarian teratocarcinoma (CH1/PA-1), cisplatin insensitive colon carcinoma (SW480) and non-small cell lung cancer (A549). Thereby, the most lipophilic (yet water soluble) platinum(IV) complexes showed promising IC50 values in the low micromolar and even nanomolar range, demonstrating the significant advantage of using equatorially coordinated monodentate carboxylato ligands. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Electrooxidation of saccharides at platinum electrode (United States)

    Han, Ji-Hyung; Chung, Taek Dong


    Saccharides have been emerging as promising fuels for future energy industry because they possess high energy density and tremendous amount of them can be obtained from abundant biomass. Direct electrochemical oxidation of saccharides to generate electricity is a potentially competitive approach in terms of the demand for small, handy, and cost-effective electric power sources. To develop efficient sugar fuel cell, it is necessary to understand mechanism of electrooxidation of saccharide at electrode surface. Although glucose oxidation at platinum surface has been well known, fundamental mechanism study on electrooxidation of other sugars is still in its infancy. Based on research of glucose oxidation, we will predict the electrooxidation of other saccharides such as fructose.

  15. Structure-based design, synthesis and biological testing of etoposide analog epipodophyllotoxin-N-mustard hybrid compounds designed to covalently bind to topoisomerase II and DNA. (United States)

    Yadav, Arun A; Wu, Xing; Patel, Daywin; Yalowich, Jack C; Hasinoff, Brian B


    Drugs that target DNA topoisomerase II isoforms and alkylate DNA represent two mechanistically distinct and clinically important classes of anticancer drugs. Guided by molecular modeling and docking a series of etoposide analog epipodophyllotoxin-N-mustard hybrid compounds were designed, synthesized and biologically characterized. These hybrids were designed to alkylate nucleophilic protein residues on topoisomerase II and thus produce inactive covalent adducts and to also alkylate DNA. The most potent hybrid had a mean GI(50) in the NCI-60 cell screen 17-fold lower than etoposide. Using a variety of in vitro and cell-based assays all of the hybrids tested were shown to target topoisomerase II. A COMPARE analysis indicated that the hybrids had NCI 60-cell growth inhibition profiles matching both etoposide and the N-mustard compounds from which they were derived. These results supported the conclusion that the hybrids displayed characteristics that were consistent with having targeted both topoisomerase II and DNA.

  16. Fabrication of iron-platinum ferromagnetic nanoparticles (United States)

    Elkins, Kevin Eugene

    Fabrication of chemically disordered FePt particles ranging from 2--9 nm with a precision of 1 nm has been achieved through modification of key process variables including surfactant concentration, heating rates and the type of iron precursor. In addition, the shape evolution of the FePt nanoparticles during particle growth can be manipulated to give cubic or rod geometries through changes to the surfactant injection sequence and solvent system. The primary method for synthesis of the disordered FePt nanoparticles is the polyol reduction reported by Fievet et al., which has been modified and used extensively for synthesis of differing nanoparticle systems. Our procedures use platinum acetylacetonate, iron pentacarbonyl or ferric acetylacetonate as precursors for the FePt alloy, oleic acid and oleyl amine for the surfactants, 1,2-hexadecanediol to assist with the reduction of the precursors and either dioctyl ether or phenyl ether for the solvent system. For iron pentacarbonyl based reactions, adjustment of heating rates to reflux temperatures from 1--15°C per minute allows control of FePt particle diameters from 3--8 nm. Substitution of iron pentacarbonyl with ferric acetylacetonate as the iron source results in 2 nm particles. A high platinum to surfactant ratio of 10 to 1 will yield 9 nm FePt particles when iron pentacarbonyl is used as the precursor. For use of these particles in advanced applications, the synthesized particles must be transformed to the L1o phase through annealing at temperatures above 500°C. Inhibition of particle sintering can be avoided through dispersion in a NaCl matrix at a weight ratio of 400 to 1 salt to fcc FePt particles. Production of L1o FePt nanoparticles with high magnetic anisotropy with this process has been successful, allowing the original size and size distribution of the particles.

  17. In vitro cytogenetic testing of an organoselenium compound and its sulfur analogue in cultured rat bone marrow cells

    Directory of Open Access Journals (Sweden)

    Jacob Jacob H


    Full Text Available Abstract Background Selenium (Se is a non-metal element, occurring in varying degrees in the environment and it has been found to be a component of several enzymes. Different selenium compounds have been associated with carcinogenicity, toxicity, modification of metal toxicity and prevention of cancer. Organoselenium compounds had substantially greater bioavailability and less toxicity than that of inorganic selenium. From a chemical point of view, Se resembles sulfur (S in many of its properties, thus, Se and S may be considered to be isosteric. The ability of a synthetic organoselenium compound; cyclopenta-dienyldicarbonyl ironselenoterephthalic acid (CSe and its sulfur analogue (CS in the range of 10-8 to 10-5 M, to induce sister-chormatid exchanges (SCE and alter cell division expressed as mitotic index (MI as well as cell survival has been investigated. Methods Rat bone marrow cells were cultured in the presence of CSe and CS in the range of 10-8 to 10-5 M with a total exposure time of 4, 16 or 28 h at 37°C. Fluorescence-plus-Giemsa (FPG technique was used to visualize chromosomes for SCE analysis and MI determination. Trypan blue exclusion technique was used to determine cell viability. Results At the three exposure times, cell survival progressively decreased with increasing concentration, but the effect of either chemical was not significant (ANOVA; P -5 M when either chemical was applied for 16 or 28 h. Furthermore, the mean SCE increased with longer exposure times and, in general, CSe had slightly greater effect on cell survival and caused higher frequencies of SCE than CS. The exception was the 10-8 M treatment. However, both CSe and CS failed to induce 2-fold SCE as that of the negative control and therefore they are not considered as mutagens. Conclusion Both CSe and CS in the range of 10-8 to 10-5 M could not double the SCE rate of the negative control and therefore not considered as mutagens at these experimental conditions.

  18. Examination of the platinum effect on the oxidation behavior ofnickel-aluminide coatings

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Peggy Y.; Tolpygo, V.K.


    Oxidation resistant nickel-aluminide coatings are designed to develop a protective alumina scale during high temperature exposure. It is well established that platinum additions, typically about 6-8 at%, provide substantial improvements in oxidation resistance of such coatings, yet the nature of the platinum effect is still not fully understood. In this work, the oxidation behavior of two commercial NiAl and NiPtAl coatings deposited on the same Ni-base single crystal alloy CMSX-4 was analyzed. Cyclic and isothermal oxidation tests were conducted at 1150 C in air. Microstructure development and alumina/coating interface chemistry were studied as a function of oxidation time. Numerous voids developed at the Al{sub 2}O{sub 3}/NiAl interface, and sulfur was found to segregate at the void surfaces and at the contact interface, leading to spallation of the scale over the convex areas along ridges on the coating surface. The presence of platinum prevented sulfur segregation and void formation at the Al{sub 2}O{sub 3}/NiPtAl interface. As a result, the Al{sub 2}O{sub 3} scale on the NiPtAl coating remained adherent and virtually no spallation was observed even after prolonged cyclic oxidation.

  19. Oxidation of H2 and CO in a fuel cell with a Platinum-tin Anode

    Directory of Open Access Journals (Sweden)

    Javier González


    Full Text Available This report describes the construction and evolution of a fuel cell with a bi-metallic anode of Pt-Sn supported on carbon, as catalysts for oxidation of pure hydrogen, pure CO and a 2% CO in H2 mixture. Both, cathode and anode were made with a structure composed by a diffusive layer and a catalytic layer. The diffusive layer was made with a carbon cloth while the catalytic layer contained the platinum and tin supported on carbon. To test the performance of the catalytic mixture, a proton exchange membrane fuel cell (PEMFC was developed with an original design for the gas distributation plates. The reactants were feed to ambient temperature and 3 psig in the anode side, while 5 psig pure oxygen was used in the cathode. The anode catalytic load was 0.57 mg/cm2 of platinum and 0.08 mg/cm2 of tin. The catalytic load in cathode was 0.85 mg/cm2 of pure platinum. It was found that this caralytic mixture is tolerant to CO presence.

  20. Sequential Electrodeposition of Platinum-Ruthenium at Boron-Doped Diamond Electrodes for Methanol Oxidation

    Directory of Open Access Journals (Sweden)

    Ileana González-González


    Full Text Available Sequential electrodeposition of Pt and Ru on boron-doped diamond (BDD films, in 0.5 M H2SO4 by cyclic voltammetry, has been prepared. The potential cycling, in the aqueous solutions of the respective metals, was between 0.00 and 1.00 V versus Ag/AgCl. The catalyst composites, Pt and PtRu, deposited on BDD film substrates, were tested for methanol oxidation. The modified diamond surfaces were also characterized by scanning electron microscopy-X-ray fluorescence-energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The scanning Auger electron spectroscopy mapping showed the ruthenium signal only in areas where platinum was electrodeposited. Ruthenium does not deposit on the oxidized diamond surface of the boron-doped diamond. Particles with 5–10% of ruthenium with respect to platinum exhibited better performance for methanol oxidation in terms of methanol oxidation peak current and chronoamperometric current stability. The electrogenerated •OH radicals on BDD may interact with Pt surface, participating in the methanol oxidation as shown in oxidation current and the shift in the peak position. The conductive diamond surface is a good candidate as the support for the platinum electrocatalyst, because it ensures catalytic activity, which compares with the used carbon, and higher stability under severe anodic and cathodic conditions.

  1. Platinum-Catalyzed Selective Tin-Carbon Bond Formation

    NARCIS (Netherlands)

    Thoonen, Sander Hendrikus Lambertus


    In conclusion, two improved methods for the selective synthesis of monoorganotin trihalides were developed. The platinum-catalyzed Kocheshkov redistribution reaction of dialkyltin dichlorides with tin tetrachloride is the most interesting. Contrary to the other two methods described (the direct

  2. Wireless gas sensing in South African underground platinum mines

    CSIR Research Space (South Africa)

    Abu-Mahfouz, Adnan M


    Full Text Available Approximately 70% of South African mines are classified as fiery, where methane gas potentially could cause explosions. The number of flammable gas reports and accidents are increasing steadily for both gold and platinum mines. However...

  3. Safety profile of Colgate Platinum Professional Toothwhitening System. (United States)

    Adam-Rodwell, G; Kong, B M; Bagley, D M; Tonucci, D; Christina, L M


    Colgate Platinum, a professional tooth-whitening paste containing 10% urea peroxide as the active ingredient, was evaluated for potential acute oral toxicity, genotoxicity, and irritation to oral mucosa. Oral administration to rats of a single dose of 5 g/kg of Colgate Platinum did not induce any adverse effects. Colgate Platinum was not mutagenic in Ames/Salmonella Plate Incorporation assay and did not induce primary DNA damage in the bone marrow hematopoietic cells of rats that were given oral doses of up to 1 g/kg for 5 consecutive days. Results of the oral mucosa irritation study in rats indicated that Colgate Platinum did not induce damage to soft and hard tissues of oral cavity after repeated applications for 28 days. Collectively, the data from these studies document the safety of the product for the intended use.

  4. Resolving the Structure of Active Sites on Platinum Catalytic Nanoparticles

    DEFF Research Database (Denmark)

    Chang, Lan Yun; Barnard, Amanda S.; Gontard, Lionel Cervera


    Accurate understanding of the structure of active sites is fundamentally important in predicting catalytic properties of heterogeneous nanocatalysts. We present an accurate determination of both experimental and theoretical atomic structures of surface monatomic steps on industrial platinum nanop...

  5. Defining Therapy for Recurrent Platinum-sensitive Ovarian Cancer (United States)

    In this phase III clinical trial, women with platinum-sensitive, recurrent ovarian epithelial, fallopian tube, or primary peritoneal cancer will be randomly assigned to undergo secondary cytoreductive surgery, if they are candidates for such surgery, and

  6. Platinum single crystal electrodes for the electrocatalysis of methane oxidation

    Directory of Open Access Journals (Sweden)

    Mayara Munaretto


    Full Text Available The main objective of this paper is to characterize the voltammetric profiles of platinum single crystals of low Miller indexes Pt(100 and Pt(110 and study their catalytic activities on the oxidation of methane. In this way, it was developed a metallic surface modified by presence of other metal oxide, which presents catalytic activity for this reaction. It is well known that the electrooxidation of methane (CH4 leads mainly to the formation of CO2 and H2O, however, the oxidation can also lead to the formation of CO, a reaction intermediate that has strong interaction with metal surfaces, such as platinum. This molecule tends to accumulate on the platinum surface and to passive it, due to the self-poisoning, decreasing its catalytic activity. Therefore, the main aim of this work was the development of a platinum electrode modified by deposition of titanium oxide, which presented electrocatalytic properties for the oxidation of methane.

  7. Platinum blue staining of cells grown in electrospun scaffolds. (United States)

    Yusuf, Mohammed; Millas, Ana Luiza G; Estandarte, Ana Katrina C; Bhella, Gurdeep K; McKean, Robert; Bittencourt, Edison; Robinson, Ian K


    Fibroblast cells grown in electrospun polymer scaffolds were stained with platinum blue, a heavy metal stain, and imaged using scanning electron microscopy. Good contrast on the cells was achieved compared with samples that were gold sputter coated. The cell morphology could be clearly observed, and the cells could be distinguished from the scaffold fibers. Here we optimized the required concentration of platinum blue for imaging cells grown in scaffolds and show that a higher concentration causes platinum aggregation. Overall, platinum blue is a useful stain for imaging cells because of its enhanced contrast using scanning electron microscopy (SEM). In the future it would be useful to investigate cell growth and morphology using three-dimensional imaging methods.

  8. Platinum electrodeposition from a dinitrosulfatoplatinate(II) electrolyte (United States)

    Weiser, Mathias; Schulze, Claudia; Schneider, Michael; Michaelis, Alexander


    In this work a halogen-free electrolyte to deposit platinum nanoparticle is studied. The investigated [Pt(NO2)2SO4]2--complex is suitable for electrochemical deposition on halogen sensitive substrates. The mechanism and kinetic of particle deposition is investigated using a glassy carbon rotating disk electrode. Nano sized platinum particles are deposited by using pulse plating technique. The size of the smallest platinum nanoparticle is 5 nm. The shape of the particle distribution strictly depends on the plating time. The platinum deposition is usually superimposed with hydrogen evolution. A diffusion coefficient of the [Pt(NO2)2SO4]2--complex is determined to 5.4 × 10-6 cm2s-1. The current efficiency depends on the deposition parameters and amounts to 37% under the chosen pulse plating conditions.

  9. Structural, mechanical and magneto-electronic properties of the ternary sodium palladium and platinum oxides

    Energy Technology Data Exchange (ETDEWEB)

    Sadiq, Saima [Malakand Univ., Chakdara Dir (Pakistan). Center for Computational Materials Science; Malakand Univ., Chakdara Dir (Pakistan). Dept. of Chemistry; Ali, Zahid; Ahmad, Iftikhar; Khan, Imad; Rehman, Gul [Malakand Univ., Chakdara Dir (Pakistan). Center for Computational Materials Science; Malakand Univ., Chakdara Dir (Pakistan). Dept. of Physics; Sadiq, Muhammad; Rehman, Najeeb Ur [Malakand Univ., Chakdara Dir (Pakistan). Dept. of Chemistry


    Ternary palladium and platinum oxides NaPd{sub 3}O{sub 4} and NaPt{sub 3}O{sub 4} are studied theoretically using DFT. The calculated structural parameters and geometry are found consistent with the experiments. The mechanical properties analysis show that both compounds are elastically stable; anisotropic and reveal the ductile nature. Electronic cloud explain that the chemical bond between Na and Pd/Pt is ionic, whereas between O and Pd/Pt is covalent. The electronic band structures and densities of states demonstrate that these compounds are metals. The d-state splitting explains the origin of the electronic behaviour of these oxides. The optimised magnetic phase energies and magnetic susceptibility confirm that these oxides are paramagnetic metals.

  10. Synthesis, characterization and biological activity of trans-platinum(II) complexes with chloroquine (United States)

    Navarro, Maribel; Castro, William; Higuera-Padilla, Angel R; Sierraalta, Anibal; Abad, María Jesús; Taylor, Peter; Sánchez-Delgado, Roberto A.


    Three platinum-chloroquine complexes, trans-Pt(CQDP)2(I)2 [1], trans-Pt(CQDP)2(Cl)2 [2] and trans-Pt(CQ)2(Cl)2 [3], were prepared and their most probable structure was established through a combination of spectroscopic analysis and density functional theory (DFT) calculations. Their interaction with DNA was studied and their activity against 6 tumor cell lines was evaluated. Compounds 1 and 2 interact with DNA primarily through electrostatic contacts and hydrogen bonding, with a minor contribution of a covalent interaction, while compound 3 binds to DNA predominantly in a covalent fashion, with weaker secondary electrostatic interactions and possibly hydrogen bonding, this complex also exerted greater cytotoxic activity against the tumor cell lines. PMID:22001497

  11. Problems and Characteristics of Russian Platinum Metals Exporters

    Institute of Scientific and Technical Information of China (English)



    The paper revealed the place and role of Russia in the global market of platinum metals,highlighted features of pricing in the export of Russian platinum group metals,the main problems of pricing in the export contracts related to the instability of markets and imperfect currency and customs legislation of the Russian Federation,proposed innovative ways to solutions to existing problems in the preparation and conclusion of export contracts.


    Institute of Scientific and Technical Information of China (English)

    CHEN Yuanyin; LU Xueran; GONG Shuling; ZHANG Baolian


    A modified method of preparing crown functionalized linear polysiloxane has been described.4'-allylbenzo-15-crown-5 was subjected to hydrosilylation with methyldichlorosilane,followed by polycondensation with silanol-terminated polydimethylsiloxane to give the title crown functionalized linear polysiloxane. It was found that the polysiloxane could be coordinated with platinum salt to form platinum complex, which could catalyze the hydrosilylation of olefins with triethoxysilane efficiently.

  13. Mineral resource of the month: platinum group metals (United States)

    Loferski, Patricia J.


    The article focuses on platinum group metals (PGMs) and their properties. According to the author, PGMs, which include iridium, osmium, palladium, platinum, rhodium, and ruthenium, are among the rarest mineral commodities in the Earth's crust. PGMs are primarily used as catalytic converters that clean harmful exhaust from vehicle engines. They are also used in the chemical industry as catalysts in the production of nitric acid and in the petroleum refining industry.

  14. In vitro evaluation of Malassezia pachydermatis susceptibility to azole compounds using E-test and CLSI microdilution methods. (United States)

    Cafarchia, Claudia; Figueredo, Luciana A; Iatta, Roberta; Colao, Valeriana; Montagna, Maria T; Otranto, Domenico


    Dermatitis caused by Malassezia spp., one of most common skin disease in dogs, requires prolonged therapy and/or high doses of antifungal agents. In the present study, the antifungal susceptibility of M. pachydermatis to ketoconazole (KTZ), fluconazole (FLZ), itraconazole (ITZ), posaconazole (POS) and voriconazole (VOR) was evaluated in vitro using both CLSI reference broth microdilution (CLSI BMD) and E-test. A total of 62 M. pachydermatis strains from dogs with and without skin lesions were tested. M. pachydermatis strains were susceptible to ITZ, KTZ and POS using both test methods, with the highest MIC found in tests of FLZ. Essential agreement between the two methods ranged from 87.1% (VOR) to 91.9% (ITZ), and categorical agreement from 74.2% (FLZ) to 96.8% (ITZ). Minor error discrepancies were observed between the two methods, with major discrepancies observed for KTZ. A higher MIC(50) value for FLZ was noted with M. pachydermatis genotype B. The MICs(50) of M. pachydermatis genotype B for KTZ, VOR and POS were higher in isolates from dogs with skin lesions than those in isolates from animals without skin lesions. The results suggest a link between genotypes of M. pachydermatis and in vitro drug susceptibility. The categorical agreement for both E-test and CLSI BMD methods found in this investigation confirms the E-test as a reliable diagnostic method for routine use in clinical mycology laboratories.

  15. Synthesis of nanosized platinum based catalyst using sol-gel process (United States)

    Ingale, S. V.; Wagh, P. B.; Bandyopadhyay, D.; Singh, I. K.; Tewari, R.; Gupta, S. C.


    The nano-sized platinum based catalysts using high surface area silica support have been prepared by sol-gel method. Tetramethoxysilane (TMOS) diluted in methanol was hydrolyzed to form a porous silica gel. Platinum (2%) was loaded at sol state using platinum chloride solution. After gelation, the solvent from the gel pores was extracted at ambient temperature which resulted in porous silica matrix incorporated with nanosized platinum. X-ray diffraction studies indicated the presence of elemental platinum in the silica-platinum composites. Transmission electron microscopy of the platinum -silica composites revealed that nanosized platinum particles of about 5-10 nm are homogeneously dispersed in silica matrix. Chemisorptions studies showed high dispersion (more than 50%) of platinum on silica support with specific surface area of 400 m2/g which puts them as promising candidates as catalyst in heterogeneous reactions.

  16. Project, fabrication, assembly and tests of different prototypes for CPS compound parabolic solar collectors; Projeto, fabricacao, montagem e testes de diferentes prototipos de coletores solares parabolicos compostos CPCs

    Energy Technology Data Exchange (ETDEWEB)

    Neto, Jose H.M. [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET), Belo Horizonte, MG (Brazil). Dept. de Engenharia Mecanica]. E-mail:


    This work presents the results of the experiment involving the design, fabrication, assembly and tests of composite parabolic solar collectors prototypes with acceptance half-angles of 3 deg C, 6.5 deg C, 11 deg C, 14 deg C and 19.5 deg C of the tube type absorber and 14 deg C rectangular absorber. Field test were performed on all the prototypes for determination of thermal efficiency, time constants and optical efficiencies represented by the modified incidence angles. Tests were performed for the determination of the heat transfer global coefficients on each prototype. (author)

  17. Calibration and field test of the Polar Organic Chemical Integrative Samplers for the determination of 15 endocrine disrupting compounds in wastewater and river water with special focus on performance reference compounds (PRC). (United States)

    Vallejo, A; Prieto, A; Moeder, M; Usobiaga, A; Zuloaga, O; Etxebarria, N; Paschke, A


    In this work, home-made Polar Organic Chemical Integrative Samplers (POCIS) were studied for passive sampling of 15 endocrine disrupting compounds (4 alkylphenols and steroid hormones) in influent and effluent samples of wastewater treatment plants (WWTPs) as well as up- and downstream of the receiving river water. POCIS calibration at laboratory conditions was carried out using a continuous-flow calibration system. The influence of the exposure position of the POCIS within the calibration device, horizontal or vertical, to the water flow direction was evaluated. While the sampling rates of most of the target substances were not affected by the sampler position, for cis-ADT, E1, E2 and E3, the vertical position provided the highest analyte accumulation. Hence, the POCIS samplers were preferably exposed vertical to the water flow in overall experiments. Using the continuous-flow calibration device, lab-based sampling rates were determined for all the target compounds (RSBPA = 0.0326 L/d; RScisADT = 0.0800 L/d, RSE1 = 0.0398 L/d, RSEQ = 0.0516 L/d, RSTT = 0.0745 L/d, RSE2 = 0.0585 L/d, RSEE2 = 0.0406 L/d, RSNT = 0.0846 L/d, RSPG = 0.0478 L/d and RSE3 = 0.1468 L/d), except for DES, MeEE2, 4tOP, 4OP, 4NPs, where the uptake after 14 days POCIS exposure was found to be insignificant or indicated a no linear behaviour. Recoveries from POCIS extractions were in the range between 71 and 152% for most of the target analytes except for DES and E3 with around 59%. Good precision of the sampling procedure up till 20% was observed and limits of detection were at ng/L level. Two deuterated compounds ([(2)H3]-E2 and [(2)H4]-EQ) were successfully tested as performance reference compounds (PRC, [Formula: see text] = 0.0507 L/d and [Formula: see text] = 0.0543 L/d)). Finally, the POCIS samplers were tested for monitoring EDCs at two wastewater treatment plants, in Halle and Leipzig (Germany). BPA, E1, EQ, E2, MeEE2, NT, EE2, PG and E3 were quantified and their time-weighted average

  18. Platinum(IV) complexes with some derivatives of 5-methyl-5-(4-pyridyl) hydantoin. Synthesis, study and comparative pharmacological investigation. (United States)

    Bakalova, A; Buyukliev, R; Ivanova, Z; Momekov, G; Ivanov, D


    3 Pt(IV) complexes with 3-ethyl-5-methyl-5-(4-pyridyl)hydantoin (4), 3-propyl-5-methyl-5-(4-pyridyl)hydantoin (5) and 3-benzyl-5-methyl-5-(4-pyridyl)hydantoin (6) with general formulae cis-[Pt(L)2Cl4] were synthesized. The novel compounds were characterized by elemental analysis, IR, 1H, 13C, NMR spectra in solid state and in solution. The studies showed that the ligands coordinate to the platinum ions in a monodentate manner through the nitrogen atom from the pyridine ring. The cytotoxic activity in vitro of newly synthesized complexes as well as their previously prepared analogous of Pt(IV) with other derivatives like 3-amino-5-methyl-5-(4-pyridyl)hydantoin (1), 5-methyl-5-(4-pyridyl)hydantoin (2), 3,5-dimethyl-5-(4-pyridyl)hydantoin (3) was screened against a panel of human tumor cell lines. The tested compounds displayed cytotoxic activity which was invariably superior with the Pt(IV) complex with 3-benzyl-5-methyl-5-(4-pyridyl)hydantoin (6) causing 50% inhibition of cellular viability at micromolar concentration, though the activity of the other studied Pt(IV) complexes proved to greatly decrease in the order 5-4-3-2-1. © Georg Thieme Verlag KG Stuttgart · New York.

  19. Platinum drugs and DNA repair mechanisms in lung cancer. (United States)

    Bonanno, Laura; Favaretto, Adolfo; Rosell, Rafael


    The standard first-line treatment for around 80% of newly-diagnosed advanced non-small cell lung cancer (NSCLC) is chemotherapy. Currently, patients are allocated to chemotherapy on the basis of clinical conditions, comorbidities and histology. If feasible, platinum-based chemotherapy is considered as the most efficacious option. Due to the heterogeneity in terms of platinum-sensitivity among patients with NSCLC, great efforts have been made in order to identify molecular predictive markers of platinum resistance. Based on the mechanism of action of platinum, several components of DNA repair pathways have been investigated as potential predictive markers. The main DNA repair pathways involved in the repair of platinum-induced DNA damage are nucleotide excision repair and homologous recombination. The most studied potential predictive markers of platinum-sensitivity are Excision Repair Cross Complementing-1 (ERCC1) and Brest Cancer Type-I Susceptibility protein (BRCA1); however, increasing biological knowledge about DNA repair pathways suggests the potential clinical usefulness of integrated analysis of multiple DNA repair components.

  20. Liposomes, a promising strategy for clinical application of platinum derivatives. (United States)

    Zalba, Sara; Garrido, María J


    Liposomes represent a versatile system for drug delivery in various pathologies. Platinum derivatives have been demonstrated to have therapeutic efficacy against several solid tumors. But their use is limited due to their side effects. Since liposomal formulations are known to reduce the toxicity of some conventional chemotherapeutic drugs, the encapsulation of platinum derivatives in these systems may be useful in reducing toxicity and maintaining an adequate therapeutic response. This review describes the strategies applied to platinum derivatives in order to improve their therapeutic activity, while reducing the incidence of side effects. It also reviews the results found in the literature for the different platinum-drugs liposomal formulations and their current status. The design of liposomes to achieve effectiveness in antitumor treatment is a goal for platinum derivatives. Liposomes can change the pharmacokinetic parameters of these encapsulated drugs, reducing their side effects. However, few liposomal formulations have demonstrated a significant advantage in therapeutic terms. Lipoplatin, a cisplatin formulation in Phase III, combines a reduction in the toxicity associated with an antitumor activity similar to the free drug. Thermosensitive or targeted liposomes for tumor therapy are also included in this review. Few articles about this strategy applied to platinum drugs can be found in the literature.

  1. In vitro permeation of platinum and rhodium through Caucasian skin. (United States)

    Franken, A; Eloff, F C; Du Plessis, J; Badenhorst, C J; Jordaan, A; Du Plessis, J L


    During platinum group metals (PGMs) refining the possibility exists for dermal exposure to PGM salts. The dermal route has been questioned as an alternative route of exposure that could contribute to employee sensitisation, even though literature has been focused on respiratory exposure. This study aimed to investigate the in vitro permeation of platinum and rhodium through intact Caucasian skin. A donor solution of 0.3mg/ml of metal, K2PtCl4 and RhCl3 respectively, was applied to the vertical Franz diffusion cells with full thickness abdominal skin. The receptor solution was removed at various intervals during the 24h experiment, and analysed with high resolution ICP-MS. Skin was digested and analysed by ICP-OES. Results indicated cumulative permeation with prolonged exposure, with a significantly higher mass of platinum permeating after 24h when compared to rhodium. The mass of platinum retained inside the skin and the flux of platinum across the skin was significantly higher than that of rhodium. Permeated and skin retained platinum and rhodium may therefore contribute to sensitisation and indicates a health risk associated with dermal exposure in the workplace.

  2. Review of different methods for developing nanoelectrocatalysts for the oxidation of organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Coutanceau, C.; Brimaud, S.; Lamy, C.; Leger, J.-M.; Dubau, L.; Rousseau, S.; Vigier, F. [Laboratoire de Catalyse en Chimie Organique, Equipe Electrocatalyse, UMR 6503 CNRS, 40 avenue du recteur Pineau, F-86022 Poitiers Cedex (France)


    Most of the electrochemical reactions involved in fuel cell are structure sensitive. Moreover, for the electrooxidation of small organic molecules catalysts have to be multifunctional. For these reasons, the development of various synthesis methods of multimetallic electrocatalysts allowing to control the atomic composition and the microstructure is needed in order to improve the electrocatalytic activity. For this purpose, several methods for the preparation of nanostructured catalysts have been developed in our laboratory (impregnation-reduction method, colloidal route, carbonyl route, microemulsion and electrochemical methods), which allow to prepare multimetallic particles. These catalysts were characterized using physical and physico-chemical methods (XRD, TEM, EDX, electrochemical methods, etc.) in order to check their composition, structure, dispersion, active surface area, etc. Amongst the developed methods, some of them can lead to the formation of alloyed or non-alloyed multimetallic compounds depending on the synthesis procedure. XRD analysis allows us to discriminate the catalyst structures. The influence of the atomic composition and of the nature of foreign metals added to platinum is discussed in terms of electrochemical activity towards oxidation of small organic molecules of interest in energy storage and production. In particular, it appears that non-alloyed Pt-Ru catalysts display higher electroactivity towards methanol oxidation. Electrochemical and DEMS measurements were used to study and to evaluate the influence of the electrocatalyst structure on its electroactivity. The effect of the composition in terms of foreign metal atoms and atomic content of platinum based and platinum-tin based catalysts towards the electrooxidation of ethanol is also discussed from electrochemical experiments and fuel cell test results. (author)

  3. Simultaneous Removal of H2S and Organosulfur Compounds from Liqueifed Petroleum Gas Using Formulated Solvents:Solubility Parameter Investigation and Industrial Test

    Institute of Scientific and Technical Information of China (English)

    Zhang Feng; Shen Benxian; Sun Hui; Liu Jichang; Shang Jianfeng


    The performance of four formulated solvents (labeled as UDS-I, UDS-II, UDS-III, and UDS-IV) for removing methyl mercaptan from liqueifed petroleum gas was predicted based on a two-dimensional solubility parameter theory. The calculation results show that UDS-IV has the closest solubility parameter to that of methyl mercaptan as compared with other tested solvents, indicating the strongest afifnity and the highest solubility for methyl mercaptan. The industrial tests at a plant for desulfurization of LPG produced from the delayed coker have shown that the UDS solvents have the excellent performance for removal of organosulfur compounds (mainly methyl mercaptan). Although the sulfur loading dramatically increases, the total sulfur content of LPG treated with UDS-IV can be reduced by about 50% in comparison withN-methyl diethanolamine. In addition, UDS-IV has superior regeneration performance and selectivity for sulfur compounds over hy-drocarbons. The industrial test and the solubility parameter calculation results are in good agreement with each other.

  4. Leachability of volatile fuel compounds from contaminated soils and the effect of plant exudates: A comparison of column and batch leaching tests. (United States)

    Balseiro-Romero, María; Kidd, Petra S; Monterroso, Carmen


    Volatile fuel compounds such as fuel oxygenates (FO) (MTBE and ETBE) and BTEX (benzene, toluene, ethylbenzene and xylene) are some of the most soluble components of fuel. Characterizing the leaching potential of these compounds is essential for predicting their mobility through the soil profile and assessing the risk of groundwater contamination. Plant root exudates can play an important role in the modification of contaminant mobility in soil-plant systems, and such effects should also be considered in leaching studies. Artificially spiked samples of A and B horizons from an alumi-umbric Cambisol were leached in packed-columns and batch experiments using Milli-Q water and plant root exudates as leaching agents. The leaching potential and rate were strongly influenced by soil-contaminant interactions and by the presence of root exudates. Organic matter in A horizon preferably sorbed the most non-polar contaminants, lowering their leaching potential, and this effect was enhanced by the presence of root exudates. On the other hand, the inorganic components of the B horizon, showed a greater affinity for polar molecules, and the presence of root exudates enhanced the desorption of the contaminants. Column experiments resulted in a more realistic protocol than batch tests for predicting the leaching potential of volatile organic compounds in dissimilar soils.

  5. Testing and linearity calibration of films of phenol compounds exposed to thermal neutron field for EPR dosimetry. (United States)

    Gallo, S; Panzeca, S; Longo, A; Altieri, S; Bentivoglio, A; Dondi, D; Marconi, R P; Protti, N; Zeffiro, A; Marrale, M


    This paper reports the preliminary results obtained by Electron Paramagnetic Resonance (EPR) measurements on films of IRGANOX® 1076 phenols with and without low content (5% by weight) of gadolinium oxide (Gd2O3) exposed in the thermal column of the Triga Mark II reactor of LENA (Laboratorio Energia Nucleare Applicata) of Pavia (Italy). Thanks to their size, the phenolic films here presented are good devices for the dosimetry of beams with high dose gradient and which require accurate knowledge of the precise dose delivered. The dependence of EPR signal as function of neutron dose was investigated in the fluence range between 10(11) cm(-2) and 10(14) cm(-2). Linearity of EPR response was found and the signal was compared with that of commercial alanine films. Our analysis showed that gadolinium oxide (5% by weight) can enhance the thermal neutron sensitivity more than 18 times. Irradiated dosimetric films of phenolic compound exhibited EPR signal fading of about 4% after 10 days from irradiation.

  6. Toxicology and metabolism of nickel compounds. Progress report, December 1, 1975--November 30, 1976. [Tests made with rats and hamsters

    Energy Technology Data Exchange (ETDEWEB)

    Sunderman, F.W. Jr.


    The toxicology and metabolism of nickel compounds (NiCl/sub 2/, Ni/sub 3/S/sub 2/, NiS, Ni powder, and Ni(CO)/sub 4/) were investigated in rats and hamsters. Triethylenetetramine (TETA) and d-penicillamine are more effective than other chelating agents (Na-diethyldithiocarbamate, CaNa/sub 2/-versenate, diglycylhistidine-N-methylamide and ..cap alpha..-lipoic acid) as antidotes for acute Ni(II)-toxicity in rats. The antidotal efficacy of triethylenetetramine (TETA) in acute Ni(II)-toxicity is mediated by rapid reduction of the plasma concentration of Ni(II), consistent with renal clearance of the TETA-Ni complex at a rate more than twenty times greater than the renal clearance of non-chelated Ni(II). Fischer rats are more susceptible than other rat strains (Wistar-Lewis, Long-Evans and NIH-Black) to induction of erythrocytosis after an intrarenal injection of Ni/sub 3/S/sub 2/, and elucidation of the serial pathologic changes that occur in rats after an intrarenal injection of Ni/sub 3/S/sub 2/. When amorphous nickel monosulfide (NiS) and nickel subsulfide (Ni/sub 3/S/sub 2/) were administered by im injection to randomly selected Fischer rats in equivalent amounts under identical conditions, NiS did not induce any tumors whereas Ni/sub 3/S/sub 2/ induced sarcomas in almost all of the rats.

  7. HET-CAM bioassay as in vitro alternative to the croton oil test for investigating steroidal and non-steroidal compounds. (United States)

    Brantner, Adelheid H; Quehenberger, Franz; Chakraborty, Asima; Polligger, Jutta; Sosa, Silvio; Della Loggia, Roberto


    In this study the irritation phenomena at the chorioallantoic membrane of incubated hen's eggs as an in vitro model (HET-CAM assay) were investigated in comparison to the in vivo croton oil test by including hydrocortisone, indomethacin, phenylbutazone, acetylsalicylic acid, rutin, quercetin, apigenin, and p-coumaric acid as steroidal and non-steroidal test substances. For the first time the two methods were compared in a valid way with the perspective of a realistic reduction of animal experiments. It should be investigated whether an in vitro-in vivo correlation exists and, if there is any possibility, to replace the in vivo model by an in vitro test system. Both bioassays were able to demonstrate the anti-inflammatory potency of the constituents tested. The determination of the anti-inflammatory activity of all compounds in the two test systems showed individual trends of inhibitory effects. However, the in vitro HET-CAM test was much more sensitive in comparison to the in vivo croton oil test. The croton oil test gave dose-effect correlations in the anti-inflammatory substances investigated. The modified HET-CAM assay did not provide clear dose-effect ratios. The HET-CAM assay is an inexpensive test being easy to manage after a short practical training. Because of its sensitivity the HET-CAM assay could be considered a suitable tool for qualitative testing of the anti-inflammatory activity of substances if no appropriate dose-effect curves are required. From these results it can be concluded that the different courses of the dose-effect curves may be primarily due to different mechanisms of action.

  8. Measuring the effects of platinum from catalytic converter equipped vehicles by means of plant indicators (food and fodder plants); Wirkungsmessungen von Platin aus katalysatorbetriebenen Kraftfahrzeugen mit pflanzlichen Bioindikatoren (Nahrungs- und Futterpflanzen)

    Energy Technology Data Exchange (ETDEWEB)

    Maier-Reiter, W.; Sommer, B. [TUEV Energie und Umwelt GmbH, Filderstadt (Germany). Niederlassung Stuttgart


    The essential aim of the present R and D project, titled ``Measuring the effects of platinum from catalytic converter equipped vehicles by means of plant indicators - food and fodder plants (VPT 02)``, was to obtain first orienting results on the potential effects of platinum pollution on plants by means of short-time, high-dose exposure experiments. The most important effect criterion in assessing potential hazards to humans and animals via the food chain, beside any outwardly visible changes (reaction), was the analytical detection of platinum accumulation in the plants. The project was also intended as a first contribution to the ecotoxicology of platinum, in particular the behaviour of metallic platinum and water-soluble platinum compounds in the soil-plant system. [Deutsch] Die wesentliche Zielsetzung des F and E-Vorhabens `Wirkungsmessungen von Platin und Platinverbindungen mit pflanzlichen Bioindikatoren - Nahrungs- und Futterpflanzen (VPT 02)` war es, im Rahmen von Kurzzeit-Belastungsexperimenten im hohen Dosisbereich erste orientierende Ergebnisse zu den moeglichen Auswirkungen von Platin-Belastungen auf Pflanzen abzuleiten. Neben aeusserlich sichtbaren Veraenderungen der Pflanzen (Reaktion) wurde als Wirkungskriterium insbesondere die chemisch-analytisch erfassbare Platin-Anreicherung in den Pflanzen (Akkumulation) betrachtet, die eine Abschaetzung moeglicher Gefaehrdungen von Mensch und Tier ueber die Nahrungskette ermoeglicht. Zudem sollte ein erster Beitrag zur Oekotoxikologie des Platins, insbesondere zum Verhalten von metallischem Platin und wasserloeslichen Platinverbindungen im System Boden-Pflanzen, erarbeitet werden. (orig.)

  9. The sensitizing potential of metalworking fluid biocides (phenolic and thiazole compounds) in the guinea-pig maximization test in relation to patch-test reactivity in eczema patients

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, K.E.; Hamann, K.


    The sensitizing potential of seven industrial antimicrobial agents was evaluated using the guinea-pig maximization test. Preventol O extra (o-phenylphenol) did not produce a sensitization reaction. Preventol ON extra (sodium salt of o-phenylphenol), Preventol GD (dichlorophene) and Proxel XL and HL containing 1,2-benzisothiazolin-3-one were weak sensitizers, while Preventol CMK and Preventol L, both containing chlorocresol, were classified as extreme potential sensitizers. Both the weak and the extreme experimental sensitizers are occasional human sensitizers. The interpretation of the test results is discussed.

  10. The sensitizing potential of metalworking fluid biocides (phenolic and thiazole compounds) in the guinea-pig maximization test in relation to patch-test reactivity in eczema patients

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Hamann, K


    containing 1,2-benzisothiazolin-3-one were weak sensitizers, while Preventol CMK and Preventol L, both containing chlorocresol, were classified as extreme potential sensitizers. Both the weak and the extreme experimental sensitizers are occasional human sensitizers. The interpretation of the test results......The sensitizing potential of seven industrial antimicrobial agents was evaluated using the guinea-pig maximization test. Preventol O extra (o-phenylphenol) did not produce a sensitization reaction. Preventol ON extra (sodium salt of o-phenylphenol), Preventol GD (dichlorophene) and Proxel XL and HL...

  11. Binding of kinetically inert metal ions to RNA: the case of platinum(II). (United States)

    Chapman, Erich G; Hostetter, Alethia A; Osborn, Maire F; Miller, Amanda L; DeRose, Victoria J


    In this chapter several aspects of Pt(II) are highlighted that focus on the properties of Pt(II)-RNA adducts and the possibility that they influence RNA-based processes in cells. Cellular distribution of Pt(II) complexes results in significant platination of RNA, and localization studies find Pt(II) in the nucleus, nucleolus, and a distribution of other sites in cells. Treatment with Pt(II) compounds disrupts RNA-based processes including enzymatic processing, splicing, and translation, and this disruption may be indicative of structural changes to RNA or RNA-protein complexes. Several RNA-Pt(II) adducts have been characterized in vitro by biochemical and other methods. Evidence for Pt(II) binding in non-helical regions and for Pt(II) cross-linking of internal loops has been found. Although platinated sites have been identified, there currently exists very little in the way of detailed structural characterization of RNA-Pt(II) adducts. Some insight into the details of Pt(II) coordination to RNA, especially RNA helices, can be gained from DNA model systems. Many RNA structures, however, contain complex tertiary folds and common, purine-rich structural elements that present suitable Pt(II) nucleophiles in unique arrangements which may hold the potential for novel types of platinum-RNA adducts. Future research aimed at structural characterization of platinum-RNA adducts may provide further insights into platinum-nucleic acid binding motifs, and perhaps provide a rationale for the observed inhibition by Pt(II) complexes of splicing, translation, and enzymatic processing.

  12. Permeation of platinum and rhodium nanoparticles through intact and damaged human skin

    Energy Technology Data Exchange (ETDEWEB)

    Mauro, Marcella [University of Trieste, Clinical Unit of Occupational Medicine, Department of Medical Sciences (Italy); Crosera, Matteo; Bianco, Carlotta; Adami, Gianpiero; Montini, Tiziano; Fornasiero, Paolo [University of Trieste, Department of Chemical and Pharmaceutical Sciences (Italy); Jaganjac, Morana [Rudjer Boskovic Institute, Laboratory for Oxidative Stress, Department of Molecular Medicine (Croatia); Bovenzi, Massimo; Filon, Francesca Larese, E-mail: [University of Trieste, Clinical Unit of Occupational Medicine, Department of Medical Sciences (Italy)


    The aim of the study was to evaluate percutaneous penetration of platinum and rhodium nanoparticles (PtNPs: 5.8 ± 0.9 nm, RhNPs: 5.3 ± 1.9 nm) through human skin. Salts compounds of these metals are sensitizers and some also carcinogenic agents. In vitro permeation experiments were performed using Franz diffusion cells with intact and damaged skin. PtNPs and RhNPs, stabilized with polyvinylpyrrolidone, were synthesized by reduction of Na{sub 2}PtC{sub l6} and RhCl{sub 3}·3H{sub 2}O respectively. Suspensions with a concentration of 2.0 g/L of PtNPs and RhNPs were dispersed separately in synthetic sweat at pH 4.5 and applied as donor phases to the outer surface of the skin for 24 h. Measurements of the content of the metals in the receiving solution and in the skin were performed subsequently. Rhodium skin permeation was demonstrated through damaged skin, with a permeation flux of 0.04 ± 0.04 μg cm{sup −2} h{sup −1} and a lag time of 7.9 ± 1.1 h, while no traces of platinum were found in receiving solutions. Platinum and rhodium skin-analysis showed significantly higher concentrations of the metals in damaged skin. Rh and Pt applied as NPs can penetrate the skin barrier and Rh can be found in receiving solutions. These experiments pointed out the need for skin contamination prevention, since even a minor injury to the skin barrier can significantly increase penetration.

  13. Exploring the possibilities of capacitively coupled contactless conductivity detection in combination with liquid chromatography for the analysis of polar compounds using aminoglycosides as test case. (United States)

    Jankovics, Péter; Chopra, Shruti; El-Attug, Mohamed N; Cabooter, Deirdre; Wolfs, Kris; Noszál, Béla; Van Schepdael, Ann; Adams, Erwin


    The analysis of highly polar (often charged) compounds which lack a strong UV absorbing chromophore is really challenging. Despite the numerous analytical methods published, the demand for a simple, robust and cheap technique for their analysis still persists. Here, reversed phase (RP) liquid chromatography (LC) with capacitively coupled contactless conductivity detection (C(4)D) was explored for the first time as a possible method for separation and detection of various aminoglycoside (AMG) antibiotics which were taken as typical test compounds: tobramycin (TOB), spectinomycin, streptomycin, amikacin, kanamycin A and kanamycin B. C(4)D was performed using a commercially available as well as a laboratory made cell. As ion-pairing reagents (IPR) four perfluorinated carboxylic acids were used: pentafluoropropionic acid, heptafluorobutyric acid, nonafluoropentanoic acid (NFPA) and pentadecafluorooctanoic acid (PDFOA). 0.125 mM NFPA-acetonitrile (ACN) (90:10) or 0.125 mM PDFOA-ACN (70:30) as mobile phases were suitable to detect TOB with reasonable retention times. However, NFPA was preferred for practical reasons. Its applicable concentration range in the mobile phase was strongly restricted by loss of chromatographic performance at lower levels and excessive background conductivity at higher levels. Overall repeatability and robustness of the method were rather poor which was explained by the relatively low IPR levels. Selectivity between the tested AMGs was mainly influenced by the number of protonated amino groups per molecule making it impossible to separate compounds of equal net charges. Problems encountered with gradient elution, hydrophilic interaction liquid chromatography (HILIC) and separation at high pH without IPRs are also discussed.

  14. Platinum- and platinum alloy-coated palladium and palladium alloy particles and uses thereof (United States)

    Adzic, Radoslav; Zhang, Junliang; Mo, Yibo; Vukmirovic, Miomir Branko


    The present invention relates to particle and nanoparticle composites useful as oxygen-reduction electrocatalysts. The particle composites are composed of a palladium or palladium-alloy particle or nanoparticle substrate coated with an atomic submonolayer, monolayer, bilayer, or trilayer of zerovalent platinum atoms. The invention also relates to a catalyst and a fuel cell containing the particle or nanoparticle composites of the invention. The invention additionally includes methods for oxygen reduction and production of electrical energy by using the particle and nanoparticle composites of the invention.

  15. Single crystal studies of platinum alloys for oxygen reduction electrodes

    DEFF Research Database (Denmark)

    Ulrikkeholm, Elisabeth Therese

    In this thesis the discovery, characterization and testing of new catalysts for the oxygen reduction reaction (ORR) is investigated. Experiments on sputter cleaned, polycrystalline Pt5Y and Pt5Gd crystals have shown that these alloys are excelent candidates for catalysts for the ORR. To mimic...... was performed on the samples as prepared, and after electrochemical cycling between 0.05 V and 1.0 V VS. RHE. and between 0.05 V and 1.2 V VS. RHE. Diffraction experiments carried out after the cycling to 1.0 V showed that an overlayer with crystalline order had been formed on the Y/Pt(111) sample and the Gd....../Pt(111) samples. These overlayers were slightly compressed compared to pure platinum and had a 6-fold symmetry. After cycling to 1.2 V VS. RHE. the correlation length of the overlayer on the Gd/Pt(111) sample had decreased significantly, and the overlayer on the Y/Pt(111) had disappeared completely...

  16. Characterization of Platinum Nanoparticles Deposited on Functionalized Graphene Sheets

    Directory of Open Access Journals (Sweden)

    Yu-Chun Chiang


    Full Text Available Due to its special electronic and ballistic transport properties, graphene has attracted much interest from researchers. In this study, platinum (Pt nanoparticles were deposited on oxidized graphene sheets (cG. The graphene sheets were applied to overcome the corrosion problems of carbon black at operating conditions of proton exchange membrane fuel cells. To enhance the interfacial interactions between the graphene sheets and the Pt nanoparticles, the oxygen-containing functional groups were introduced onto the surface of graphene sheets. The results showed the Pt nanoparticles were uniformly dispersed on the surface of graphene sheets with a mean Pt particle size of 2.08 nm. The Pt nanoparticles deposited on graphene sheets exhibited better crystallinity and higher oxygen resistance. The metal Pt was the predominant Pt chemical state on Pt/cG (60.4%. The results from the cyclic voltammetry analysis showed the value of the electrochemical surface area (ECSA was 88 m2/g (Pt/cG, much higher than that of Pt/C (46 m2/g. The long-term test illustrated the degradation in ECSA exhibited the order of Pt/C (33% > Pt/cG (7%. The values of the utilization efficiency were calculated to be 64% for Pt/cG and 32% for Pt/C.

  17. Characterization of the Key Aroma Compounds in Chinese Vidal Icewine by Gas Chromatography-Olfactometry, Quantitative Measurements, Aroma Recombination, and Omission Tests. (United States)

    Ma, Yue; Tang, Ke; Xu, Yan; Li, Ji-Ming


    The key aroma compounds of Chinese Vidal icewine were characterized by means of gas chromatography-olfactometry (GC-O) coupled with mass spectrometry (MS) on polar and nonpolar columns, and their flavor dilution (FD) factors were determined by aroma extract dilution analysis (AEDA). A total of 59 odor-active aroma compounds in three ranks of Vidal icewines were identified, and 28 odorants (FD ≥ 9) were further quantitated for aroma reconstitution and omission tests. β-Damascenone showed the highest FD value of 2187 in all icewines. Methional and furaneol were first observed as important odorants in Vidal icewine. Aroma recombination experiments revealed a good similarity containing the 28 important aromas. Omission tests corroborated the significant contribution of β-damascenone and the entire group of esters. Besides, 4-hydroxy-2,5-dimethyl-3(2H)-furanone (furaneol) and 3-(methylthio)-1-propanal (methional) also had significant effects on icewine character, especially on apricot, caramel, and tropical fruit characteristics.

  18. A 155-plex high-throughput in vitro coregulator binding assay for (anti-)estrogenicity testing evaluated with 23 reference compounds. (United States)

    Wang, Si; Houtman, René; Melchers, Diana; Aarts, Jac; Peijnenburg, Ad; van Beuningen, Rinie; Rietjens, Ivonne; Bovee, Toine F


    To further develop an integrated in vitro testing strategy for replacement of in vivo tests for (anti-)estrogenicity testing, the ligand-modulated interaction of coregulators with estrogen receptor α was assessed using a PamChip® plate. The relative estrogenic potencies determined, based on ERα binding to coregulator peptides in the presence of ligands on the PamChip® plate, were compared to the relative estrogenic potencies as determined in the in vivo uterotrophic assay. The results show that the estrogenic potencies predicted by the 57 coactivators on the peptide microarray for 18 compounds that display a clear E2 dose-dependent response (goodness of fit of a logistic dose-response model of 0.90 or higher) correlated very well with their in vivo potencies in the uterotrophic assay, i.e., coefficient of determination values for 30 coactivators higher than or equal to 0.85. Moreover, this coregulator binding assay is able to distinguish ER agonists from ER antagonists: profiles of selective estrogen receptor modulators, such as tamoxifen, were distinct from those of pure ER agonists, such as dienestrol. Combination of this coregulator binding assay with other types of in vitro assays, e.g., reporter gene assays and the H295R steroidogenesis assay, will frame an in vitro test panel for screening and prioritization of chemicals, thereby contributing to the reduction and ultimately the replacement of animal testing for (anti-)estrogenic effects.

  19. Clinical pharmacology and pharmacokinetics of cis-platinum and analogs. (United States)

    Ribaud, P; Gouveia, J; Bonnay, M; Mathe, G


    cis-Platinum (DDP), the first metal coordination complex introduced into clinical trials, is remarkable for its therapeutic index. A short review of the numerator of this index, ie, the clinical activities of DDP given as a single agent or in combination therapy is presented. Toxicity of DDP, the denominator of the index, is given more attention, particularly nephrotoxicity, whose cumulative character and molecular mechanism are still in question and which can most often be prevented by following certain safety rules that are detailed in this paper. Pharmacokinetics data of free and filterable platinum are reviewed and discussed according to the different modalities of administration of DDP, and to what is known about its toxicity and its mechanism of cell kill. The rationale for using DDP in combination treatment is presented and the question of possible long-term toxicities is raised. cis-platinum analogs are sought for the purpose of enlarging the spectrum of activity, increasing selectivity and diminishing toxicity. Malonato-platinum has been shown not to be cross-resistant with DDP and to be clinically effective in adult acute leukemia. In a phase I study, malonato-platinum, which is poorly soluble, was administered in 6-24-hour infusions to 49 patients in doses ranging from 3 to 32 mg/kg. GI toxicity was universal. Hematological toxicity appeared to be mild and not clearly dose-related (the 3-32 mg/kg patients were not yet evaluable). Platinum pharmacokinetics in urine and plasma were performed using flameless absorption spectrophotometry. Preliminary results have suggested that malonato-platinum presented several pharmacokinetic features in common with DDP. Minor responses were seen in four solid tumor patients, three of whom were refractory to DDP. Other analogs soon to be introduced into clinical trials are listed.

  20. Platinum metals in magmatic sulfide ores (United States)

    Naldrett, A.J.; Duke, J.M.


    Platinum-group elements (PGE) are mined predominantly from deposits that have formed by the segregation of molten iron-nickel-copper sulfides from silicate magmas. The absolute concentrations of PGE in sulfides from different deposits vary over a range of five orders of magnitude, whereas those of other chalcophile elements vary by factors of only 2 to 100. However, the relative proportions of the different PGE in a given deposit are systematically related to the nature of the parent magma. The absolute and relative concentrations of PGE in magmatic sulfides are explained in terms of the degree of partial melting of mantle peridotite required to produce the parent magma and the processes of batch equilibration and fractional segregation of sulfides. The Republic of South Africa and the U.S.S.R. together possess more than 97 percent of the world PGE reserves, but significant undeveloped resources occur in North America. The Stillwater complex in Montana is perhaps the most important example. Copyright ?? 1980 AAAS.

  1. Platinum states in citrate sols by EXAFS. (United States)

    Lin, Chia-Shiang; Khan, Maksudur R; Lin, Shawn D


    Platinum sols have been prepared by citrate reduction in the temperature range of 343-363 K. The Pt state in the solution was examined by EXAFS (extended X-ray absorption fine-structure spectroscopy). It did not show any PtPt bonding, a characteristic for reduced Pt sols. EXAFS model fitting further proved the presence of PtO with 4 oxygen neighbors, which suggests a tetraplanar coordination configuration. The possibility of neighboring Pt sharing oxygen ligand or the formation of PtO(x) is rejected by EXAFS model fitting. Citrate was found to be the most likely ligand to orient its oxygen end toward a charged Pt center. Thus we have revealed that the citrate treatment at this temperature range was clearly insufficient to reduce H2PtCl(6(aq)). Neither an extended period of reaction time nor an excess citrate reduced the Pt precursor. It is therefore highly recommended that the citrate sols should be carefully prepared and used.

  2. Development of radioactive platinum group metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.S.; Kim, Y.S.; Kim, Y.E. [and others


    The fission product nuclides generated during the irradiation of reactor fuel include many useful elements, among them platinum group metals such as ruthenium, rhodium and palladium which are of great industrial importance, occur rarely in nature and are highly valuable. In this research, the authors reviewed various PGM recovery methods. Recovery of palladium from seven-component simulated waste solutions was conducted by selective precipitation method. The recovery yield was more than 99.5% and the purity of the product was more than 99%. Wet-proof catalyst was prepared with the recovered palladium. The specific surface area of the catalyst support was more than 400m{sup 2}/g.The content of palladium impregnated on the support was 1 to 10 wt. %. Hydrogen isotope exchange efficiency of more than 93% to equilibrium with small amount of the catalyst was obtained. It was turned out possible to consider using such palladium or other very low active PGM materials in applications where its activity is unimportant as in nuclear industries. (author). 86 refs., 44 tabs., 88 figs.

  3. Development of radioactive platinum group metal catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H.S.; Kim, Y.S.; Kim, Y.E. [and others


    The fission product nuclides generated during the irradiation of reactor fuel include many useful elements, among them platinum group metals such as ruthenium, rhodium and palladium which are of great industrial importance, occur rarely in nature and are highly valuable. In this research, the authors reviewed various PGM recovery methods. Recovery of palladium from seven-component simulated waste solutions was conducted by selective precipitation method. The recovery yield was more than 99.5% and the purity of the product was more than 99%. Wet-proof catalyst was prepared with the recovered palladium. The specific surface area of the catalyst support was more than 400m{sup 2}/g.The content of palladium impregnated on the support was 1 to 10 wt. %. Hydrogen isotope exchange efficiency of more than 93% to equilibrium with small amount of the catalyst was obtained. It was turned out possible to consider using such palladium or other very low active PGM materials in applications where its activity is unimportant as in nuclear industries. (author). 86 refs., 44 tabs., 88 figs.

  4. Coatings of Different Carbon Nanotubes on Platinum Electrodes for Neuronal Devices: Preparation, Cytocompatibility and Interaction with Spiral Ganglion Cells.

    Directory of Open Access Journals (Sweden)

    Niklas Burblies

    Full Text Available Cochlear and deep brain implants are prominent examples for neuronal prostheses with clinical relevance. Current research focuses on the improvement of the long-term functionality and the size reduction of neural interface electrodes. A promising approach is the application of carbon nanotubes (CNTs, either as pure electrodes but especially as coating material for electrodes. The interaction of CNTs with neuronal cells has shown promising results in various studies, but these appear to depend on the specific type of neurons as well as on the kind of nanotubes. To evaluate a potential application of carbon nanotube coatings for cochlear electrodes, it is necessary to investigate the cytocompatibility of carbon nanotube coatings on platinum for the specific type of neuron in the inner ear, namely spiral ganglion neurons. In this study we have combined the chemical processing of as-delivered CNTs, the fabrication of coatings on platinum, and the characterization of the electrical properties of the coatings as well as a general cytocompatibility testing and the first cell culture investigations of CNTs with spiral ganglion neurons. By applying a modification process to three different as-received CNTs via a reflux treatment with nitric acid, long-term stable aqueous CNT dispersions free of dispersing agents were obtained. These were used to coat platinum substrates by an automated spray-coating process. These coatings enhance the electrical properties of platinum electrodes, decreasing the impedance values and raising the capacitances. Cell culture investigations of the different CNT coatings on platinum with NIH3T3 fibroblasts attest an overall good cytocompatibility of these coatings. For spiral ganglion neurons, this can also be observed but a desired positive effect of the CNTs on the neurons is absent. Furthermore, we found that the well-established DAPI staining assay does not function on the coatings prepared from single-wall nanotubes.

  5. 仿生复眼结构的制作与测试研究%Fabrication and Test Study of Bionic Compound Eye

    Institute of Scientific and Technical Information of China (English)

    陈德沅; 石云波; 邹坤; 贺婷


    为了更好地利用生物复眼的光学性能,介绍了一种新型仿生复眼结构。通过使用传统光刻胶热熔法和NOA73紫外曝光固化技术,得到了NOA73和PDMS材料的微透镜阵列,比较了它们的聚焦效果和光强分布,得到NOA73材料具有更好的光学性能;然后利用PDMS的柔韧性进行了两次倒模,再通过紫外曝光把NOA73固化,得到了背靠背形式的仿生复眼结构;最后对结构进行了成像测试、光强分布测试,并对结果进行了仿真和理论分析,可知该结构具有良好的形貌,光损耗小,光学性能优异并且具有很好的重复性,制作简单,成本低,能够模仿生物复眼的部分光学特性。%This paper presents a novel biomimetic compound eye structure in order to make better use of biological compound eyes’optical properties. We have made NOA73 and PDMS micro-lens array by using conventional photo⁃resist melting method and NOA73 UV curing technology,and certificated NOA73 has better optical performance by comparing their focusing effect and the light intensity distribution. Then using the PDMS flexible characteristics and NOA73 UV curing properties to make the back-to-back bionic compound eye structure. Finally making imaging tests,intensity distribution tests,simulation and theoretical analysis,the result shows that the structure has a good morphology,small optical loss,excellent optical performance and good reproducibility. It is simply made,low cost, and capable of imitating the part of optical properties of biological compound eyes structure.

  6. Structural and functional evaluation of interaction between mammalian ribosomal RNA with platinum-containing antineoplastic drugs. (United States)

    Theile, Dirk; Kos, Martin


    Cisplatin, oxaliplatin, and carboplatin primarily target DNA, but also alter RNA functionality, albeit to different extent. This study determined the in vitro cytotoxicity (IC50 values) of platinum drugs in LS180 cells and compared the rRNA platination patterns following IC50 exposure. Relevance of particular secondary RNA structures for platination susceptibility was evaluated by primer extension methodology using 18S rRNA as a model RNA. Consequences of rRNA platination for translation efficiency were evaluated by monitoring fluorescence of a destabilised green fluorescent protein variant through flow cytometry. Oxaliplatin and cisplatin were most cytotoxic with IC50 values of 1.7 μM±0.8 and 4.1 μM±0.1, respectively. Carboplatin was significantly less efficient (IC50 147.1 μM±19.4). When exposed to equitoxic concentrations (respective IC50), all three compounds caused similar stop signal incidence or intensity. Moreover, the same rRNA sites were targeted without selectivity for particular secondary structures but with a slight preference for guanine-rich regions. Compared to cycloheximide, none of the drugs diminished translation efficiency at typical in vivo concentrations. In conclusion, equitoxic concentrations of platinum drugs target the same sites in cellular rRNA and cause similar platination intensities. At pharmacokinetically relevant concentrations, cisplatin, oxaliplatin or carboplatin do not inhibit translation efficiency. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Stereochemical control of nucleosome targeting by platinum-intercalator antitumor agents. (United States)

    Chua, Eugene Y D; Davey, Gabriela E; Chin, Chee Fei; Dröge, Peter; Ang, Wee Han; Davey, Curt A


    Platinum-based anticancer drugs act therapeutically by forming DNA adducts, but suffer from severe toxicity and resistance problems, which have not been overcome in spite of decades of research. And yet defined chromatin targets have generally not been considered in the drug development process. Here we designed novel platinum-intercalator species to target a highly deformed DNA site near the nucleosome center. Between two seemingly similar structural isomers, we find a striking difference in DNA site selectivity in vitro, which comes about from stereochemical constraints that limit the reactivity of the trans isomer to special DNA sequence elements while still allowing the cis isomer to efficiently form adducts at internal sites in the nucleosome core. This gives the potential for controlling nucleosome site targeting in vivo, which would engender sensitivity to epigenetic distinctions and in particular cell type/status-dependent differences in nucleosome positioning. Moreover, while both compounds yield very similar DNA-adduct structures and display antitumor cell activity rivalling that of cisplatin, the cis isomer, relative to the trans, has a much more rapid cytotoxic effect and distinct impact on cell function. The novel stereochemical principles for controlling DNA site selectivity we discovered could aid in the design of improved site discriminating agents. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  8. Nanoparticulate platinum films on gold using dendrimer-based wet chemical method

    Indian Academy of Sciences (India)

    S Raghu; Sheela Berchmans; K L N Phani; V Yegnaraman


    There is a growing interest in devising wet chemical alternatives for physical deposition methods for applications involving thin films, e.g., catalysis. Deposition of platinum on thin gold films is often a problem leading to incomplete coverage and improper adhesion to solid surfaces. Gold substrates often need pre-activation for achieving complete coverage. We demonstrate here that dendrimers with proper functionalities and size work as well-defined nucleating agents and adhesion promoters. This feature is demonstrated using an amine-terminated dendrimer of generation 4.0. This approach allows one to obtain adherent nanoparticulate films of platinum on gold. Unlike other nucleating agents and adhesion promoting compounds, dendrimers have a well-defined ordered structure in terms of their space filling ability. The stability of the films obtained with adsorbed dendrimers is emonstrated using the electrocatalytic reactions of fuels like methanol. The films formed without dendrimers cannot sustain the electro-oxidation currents due to the instability of the films while the films formed with dendrimers can sustain currents for longer duration and for several cycles. The dendrimer-derived Pt films exhibit higher catalytic activity compared to other methods.

  9. Microwave-assisted synthesis and photocatalytic properties of sulphur and platinum modified TiO2 nanofibers (United States)

    Drunka, R.; Grabis, J.; Jankovica, Dz; Krumina, A.; Rasmane, Dz


    In the present work formation of active TiO2 nanofibers in microwave synthesis and their modification with platinum were studied. Mixture of anatase and rutile nanopowder and 10M KOH solution were used as raw materials. Microwave assisted synthesis method permitted to obtain TiO2 nanofibres with a diameter of 10nm and a specific surface area up to 40.2 m2/g. In order to modify TiO2 nanofibers with platinum it was stirred in H2PtCl6 solution and illuminated with UV irradiation or reduced with sodium boronhydride. To modify titania with sulphur and prepare co-doped nanofibers platinum doped samples were extra treated in hydrogen sulphide atmosphere. Photocatalytic activity was determined by degradation of the methylene blue (MB) solution under UV and visible light irradiation. The obtained samples showed higher photocatalytic activity with respect to pure TiO2 nanofibers. The doped TiO2 nanofibers were appropriate for degradation of harmful organic compounds.

  10. Synthesis and characterization of potential iron–platinum drugs and supplements by laser liquid photolysis

    CSIR Research Space (South Africa)

    Nkosi, SS


    Full Text Available , and structure was systematically investigated. Different nanostructures of iron–platinum alloy and chemically disordered iron–platinum L10 phase were obtained without annealing. The prepared precursor solution underwent deep photolysis to polycrystalline iron...

  11. A dual-emissive ionic liquid based on an anionic platinum(II) complex


    Ogawa, Tomohiro; Yoshida, Masaki; Ohara, Hiroki; Kobayashia, Atsushi; Kato, Masako


    An ionic liquid fabricated froman anionic cyclometalated platinum(II) complex and an imidazolium cation exhibits dual emission from the monomeric and aggregated forms of the platinum complex anions, leading to temperature-dependent color changes of luminescence.

  12. A dual-emissive ionic liquid based on an anionic platinum(ii) complex. (United States)

    Ogawa, Tomohiro; Yoshida, Masaki; Ohara, Hiroki; Kobayashi, Atsushi; Kato, Masako


    An ionic liquid fabricated from an anionic cyclometalated platinum(ii) complex and an imidazolium cation exhibits dual emission from the monomeric and aggregated forms of the platinum complex anions, leading to temperature-dependent color changes of luminescence.

  13. The influence of reduction methods and conditions on the activity of alumina-supported platinum catalysts for the liquid phase hydrogenation of benzaldehyde in ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Arai, M.; Obata, A.; Nishiyama, Y. [Tohoku Univ., Sendai (Japan)


    The activities of supported metal catalysts depend on various preparation variables, including the method of reduction. A variety of reduction procedures can be applied to the preparation of supported metal catalysts. Previously, the authors used a solid-liquid reduction by sodium tetrahydroborate solution for preparing supported platinum catalysts. In this reduction, platinum precursors adsorbed on supports were brought into contact with the reducing solution. The alumina-supported platinum catalysts prepared in this way were found to display interesting activities in the liquid-phase hydrogenation of {alpha},{beta}-unsaturated aldehydes; they were highly selective to the formation of unsaturated alcohols. The selective hydrogenation of C=O bonds of {alpha},{beta}-unsaturated aldehydes is difficult to achieve with platinum catalysts without using some additives like tin and iron. The maximum temperature that the supported platinum catalysts went through was 110{degrees}C, required for the removal of water. This thermal history is a possible reason for the catalytic activity observed. Following those observations, in the present work, the authors have further examined the influence of reduction procedures by using hydrazine as well as sodium tetrahydroborate and different temperatures common during gas-phase reduction with hydrogen. The catalytic activity has been tested by the liquid-phase hydrogenation of benzaldehyde (BAL) in ethanol under mild conditions. 12 refs., 3 figs.

  14. Pharmacokinetics of Malonato (1,2 diaminocyclohexane) platinum. (United States)

    Kelsen, D P; Ribaud, P; Alcock, N; Burchenal, J H; Young, C W; Mathe, G


    Malonato-(1,2 diaminocyclohexane) platinum (MP) is a new platinum analog currently undergoing phase I clinical trials. Using flameless atomic absorption spectrophotometry, the pharmacokinetics of MP were studied at five dosage levels. The drug was given as a prolonged intravenous infusion, lasting from 6 to 24 hours. Peak plasma platinum concentrations (Pt) were seen at the end of the infusion, and ranged from 1.1 microgram/ml when 3 mg/kg was given to 14-20.5 micrograms/ml at the 24-mg/kg level. Following completion of the infusion, a prolonged T1/2 beta (mean 63.5 hours) was noted. The percentage of free:total platinum was high (90-95%) at the beginning of the infusion but fell rapidly, to only 15-21% at the end of the 24-hour infusions. Urinary excretion accounted for 16-37.5% of the total administered dose. MP appears to have several pharmacokinetic features in common with cisplatin: rapid binding to protein, a prolonged terminal phase half-life involving primarily bound platinum, and incomplete excretion by the kidney.

  15. Structures of 38-atom gold-platinum nanoalloy clusters

    Energy Technology Data Exchange (ETDEWEB)

    Ong, Yee Pin; Yoon, Tiem Leong [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lim, Thong Leng [Faculty of Engineering and Technology, Multimedia University, Melaka Campus, 75450 Melaka (Malaysia)


    Bimetallic nanoclusters, such as gold-platinum nanoclusters, are nanomaterials promising wide range of applications. We perform a numerical study of 38-atom gold-platinum nanoalloy clusters, Au{sub n}Pt{sub 38−n} (0 ≤ n ≤ 38), to elucidate the geometrical structures of these clusters. The lowest-energy structures of these bimetallic nanoclusters at the semi-empirical level are obtained via a global-minimum search algorithm known as parallel tempering multi-canonical basin hopping plus genetic algorithm (PTMBHGA), in which empirical Gupta many-body potential is used to describe the inter-atomic interactions among the constituent atoms. The structures of gold-platinum nanoalloy clusters are predicted to be core-shell segregated nanoclusters. Gold atoms are observed to preferentially occupy the surface of the clusters, while platinum atoms tend to occupy the core due to the slightly smaller atomic radius of platinum as compared to gold’s. The evolution of the geometrical structure of 38-atom Au-Pt clusters displays striking similarity with that of 38-atom Au-Cu nanoalloy clusters as reported in the literature.

  16. Dual-drug delivery of curcumin and platinum drugs in polymeric micelles enhances the synergistic effects: a double act for the treatment of multidrug-resistant cancer. (United States)

    Scarano, Wei; de Souza, Paul; Stenzel, Martina H


    Combinational chemotherapy is often used to prevent drug induced resistance in cancer. The aim of this work is to test whether the co-delivery of drugs within one nanoparticle can result in increased synergistic effects of both drugs. Therefore, a micelle system with two different compartments, one for the drug curcumin and one for the conjugation of platinum drugs was designed. A triblock copolymer, based on the biodegradable polycaprolactone PCL, a PEG based shell and an amine bearing polymer as the interphase for the conjugation of platinum drugs was prepared by combination of ring-opening polymerization and RAFT polymerization. Curcumin was incorporated into the self-assembled onion-type micelle by physical encapsulation into the PCL core with an entrapment capacity of 6 wt%. The platinum(iv) drug oxoplatin was reacted with succinic anhydride to yield Pt(NH3)2Cl2[(COOH)2], which acted as the drug and as a crosslinker for the stabilisation of micelles. The size of the dual drug micelles was measured to be 38 nm by DLS, which was confirmed by TEM. The toxicity of the dual drug delivery system was tested against the A2780 human ovarian cancer cell line and compared with the IC50 value of micelles that deliver either curcumin or the platinum drug alone. The results were analysed using the CalcuSyn software. While curcumin and the platinum drug together without a carrier already showed synergy with a combination index ranging from 0.4 to 0.8, the combined delivery in one nanoparticle did enhance the synergistic effects resulting in a combination index of approximately 0.2-0.35. For comparison, a mixture of two nanoparticles, one with curcumin and the other with the platinum drug, was tested revealing a less noticeable synergistic effect compared to the co-delivery of both drugs in one drug carrier.

  17. Chemical stabilization of metals in mine wastes by transformed red mud and other iron compounds: laboratory tests. (United States)

    Ardau, C; Lattanzi, P; Peretti, R; Zucca, A


    A series of static and kinetic laboratory-scale tests were designed in order to evaluate the efficacy of transformed red mud (TRM) from bauxite refining residues, commercial zero-valent iron, and synthetic iron (III) hydroxides as sorbents/reagents to minimize the generation of acid drainage and the release of toxic elements from multi-contaminant-laden mine wastes. In particular, in some column experiments the percolation of meteoric water through a waste pile, alternated with periods of dryness, was simulated. Wastes were placed in columns together with sorbents/reagents in three different set-ups: as blended amendment (mixing method), as a bed at the bottom of the column (filtration method), or as a combination of the two previous methods. The filtration methods, which simulate the creation of a permeable reactive barrier downstream of a waste pile, are the most effective, while the use of sorbents/reagents as amendments leads to unsatisfactory results, because of the selective removal of only some contaminants. The efficacy of the filtration method is not significantly affected by the periods of dryness, except for a temporary rise of metal contents in the leachates due to dissolution of soluble salts formed upon evaporation in the dry periods. These results offer original information on advantages/limits in the use of TRM for the treatment of multi-contaminant-laden mine wastes, and represent the starting point for experimentation at larger scale.

  18. Antifungal testing and high-throughput screening of compound library against Geomyces destructans, the etiologic agent of geomycosis (WNS in bats.

    Directory of Open Access Journals (Sweden)

    Sudha Chaturvedi

    Full Text Available Bats in the northeastern U.S. are affected by geomycosis caused by the fungus Geomyces destructans (Gd. This infection is commonly referred to as White Nose Syndrome (WNS. Over a million hibernating bats have died since the fungus was first discovered in 2006 in a cave near Albany, New York. A population viability analysis conducted on little brown bats (Myotis lucifugus, one of six bat species infected with Gd, suggests regional extinction of this species within 20 years. The fungus Gd is a psychrophile ("cold loving", but nothing is known about how it thrives at low temperatures and what pathogenic attributes allow it to infect bats. This study aimed to determine if currently available antifungal drugs and biocides are effective against Gd. We tested five Gd strains for their susceptibility to antifungal drugs and high-throughput screened (HTS one representative strain with SpectrumPlus compound library containing 1,920 compounds. The results indicated that Gd is susceptible to a number of antifungal drugs at concentrations similar to the susceptibility range of human pathogenic fungi. Strains of Gd were susceptible to amphotericin B, fluconazole, itraconazole, ketoconazole and voriconazole. In contrast, very high MICs (minimum inhibitory concentrations of flucytosine and echinocandins were needed for growth inhibition, which were suggestive of fungal resistance to these drugs. Of the 1,920 compounds in the library, a few caused 50%--to greater than 90% inhibition of Gd growth. A number of azole antifungals, a fungicide, and some biocides caused prominent growth inhibition. Our results could provide a theoretical basis for future strategies aimed at the rehabilitation of most affected bat species and for decontamination of Gd in the cave environment.

  19. Electrochemical Tailoring of Fibrous Polyaniline and Electroless Decoration with Gold and Platinum Nanoparticles. (United States)

    Abdelhamid, Muhammad E; Snook, Graeme A; O'Mullane, Anthony P


    Presented in this work is a facile and quick electrochemical method for controlling the morphology of thick polyaniline (PANi) films, without the use of templates. By stepping the polymerization potential from high voltages to a lower (or series of lower) voltage(s), we successfully controlled the morphology of the polymer, and fibrous structures, unique to each potential step, were achieved. In addition, the resultant film was tested electrochemically for its viability as an electrode material for flexible batteries and supercapacitors. Furthermore, the PANi film was decorated with gold and platinum nanoparticles via an electroless deposition process for possible electrocatalytic applications, whereby the oxidation of hydrazine at the composite was investigated.

  20. Active and stable platinum/ionic liquid/carbon nanotube electrocatalysts for oxidation of methanol


    Guan-Lin Lin; Arun Prakash Periasamy; Zih-Yu Shih; Huan-Tsung Chang


    Platinum (Pt) nanoparticles (NPs) on carbon nanotubes (CNTs) from PtCl62− ions through a facile ionic liquid (IL)-assisted method has been developed and used for methanol oxidation. 1-Butyl-3-methylimidazolium (BMIM) with four different counter ions (PF6−, Cl–, Br–, and I–) have been tested for the preparation of Pt/IL/CNT nanohybrids, showing the counterions of ILs play an important role in the formation of small sizes of Pt NPs. Only [BMIM][PF6] and [BMIM][Cl] allow reproducible preparation...

  1. The Researches on Performance and Technology of Strengthened Pure Platinum Wire

    Institute of Scientific and Technical Information of China (English)

    ZHAI Buying; WU Baoan; PAN Xiong; YANG Hao; WANG Yunchun; CHEN Xiaojun; WANG Jianshen; LI Guogang; XUE Liqian


    This paper discusses about the purity of strengthened pure platinum wire and the development method of platinum micro wire,in order to solve the difficulties of low tensile strength,easy to break,and low rate of micro wire.And it contrasts some performance of strengthened pure platinum wire and sponge Pt wire.The researches draw a conclusion that the thermoelectric properties of strengthened pure platinum micro wire was in accordance with national standards and satisfied users' requirements.

  2. Oxidative-addition reactions of cyclometallated platinum(II) compounds with mercury(II) carboxylates. X-ray, crystal and molecular structure of rac-[a-(m-MeCO2)-cf,de-(2-Me2NCH2C6H4)2PtHg(O2CMe)

    NARCIS (Netherlands)

    Koten, G. van; Ploeg, A.F.M.J. van der; Vrieze, K.; Spek, A.L.


    The reactions of C~~-[(~-M~~NCo~btHain~edC fHrom~ )[P~tCP12~(S~Et2])2,a] n d [(2-MeJW6H4CH2)Li(TMEDA)] (TMEDA = tetramethylethylenediamine), and of cis-[( 2-Me2NCH2C6H4)2Pt1w1]i th Hg11(02CR)2( R = Me, i-Pr) yielded a novel type of cyclometalated Pt-Hg compound [(N-C)2(RCOJPtHg(02CR)] (N-C = 2-Me@C6

  3. Inhibition of nucleic acid synthesis in P388 lymphocytic leukemia cells in culture by cis-platinum derivatives. (United States)

    Oswald, C B; Chaney, S G; Hall, I H


    Cis-diaminedichloroplatinum(II) [cDDP] and three related derivatives Pt(mal)(NH3)2, PtCl2(dach) and Pt(mal) (dach) have been observed to possess cytotoxicity against the growth of P388 lymphocytic leukemia cells. DNA synthesis in P388 cells was inhibited by the agents in a manner which was consistent with their ED50 values for cytotoxicity. When P388 cells were treated with these platinum complexes in vitro at doses which caused more than 80% inhibition of DNA synthesis, no significant inhibition was observed for thymidine, kinase, thymidine monophosphate kinase, carbamoyl phosphate synthetase, or aspartate transcarbamoylase activities. Thus, there was no evidence that these agents inhibited de novo purine, pyrmidine, or deoxynucleotide synthesis. All of the agents did inhibit the nuclear DNA polymerase activity, but the extent of inhibition was 20% or less at doses which caused greater than 70% inhibition of DNA synthesis. Thus, the inhibition of DNA synthesis appeared to be due to cisplatinum(II) drug binding to the DNA bases. This was estimated to be 1 atom of platinum per 1500-3000 DNA base pairs which is consistent with other studies. The platinum complexes with chloro leaving ligands caused considerable DNA strand scission by 24 h at 10 times the ED50 dose, most likely a measure of impending cell death. In contrast, the platinum complexes with malonato leaving ligands did not cause significant strand scission by 24 h at similar doses. They also exhibited a significant delay in the inhibition of DNA synthesis. These data were interpreted as resulting from slower monoadduct to diadduct conversion, but it is not possible to eliminate the possibility of a different mode of interaction with DNA or a different mechanism of cytotoxicity for the malonato compounds.

  4. Large-scale evaluation of log P predictors: local corrections may compensate insufficient accuracy and need of experimentally testing every other compound. (United States)

    Tetko, Igor V; Poda, Gennadiy I; Ostermann, Claude; Mannhold, Raimund


    A large variety of log P calculation methods failed to produce sufficient accuracy in log P prediction for two in-house datasets of more than 96000 compounds contrary to their significantly better performances on public datasets. The minimum Root Mean Squared Error (RMSE) of 1.02 and 0.65 were calculated for the Pfizer and Nycomed datasets, respectively, in the 'out-of-box' implementation. Importantly, the use of local corrections (LC) implemented in the ALOGPS program based on experimental in-house log P data significantly reduced the RMSE to 0.59 and 0.48 for the Pfizer and Nycomed datasets, respectively, instantly without retraining the model. Moreover, more than 60% of molecules predicted with the highest confidence in each set had a mean absolute error (MAE) less than 0.33 log units that is only ca. 10% higher than the estimated variation in experimental log P measurements for the Pfizer dataset. Therefore, following this retrospective analysis, we suggest that the use of the predicted log P values with high confidence may eliminate the need of experimentally testing every other compound. This strategy could reduce the cost of measurements for pharmaceutical companies by a factor of 2, increase the confidence in prediction at the analog design stage of drug discovery programs, and could be extended to other ADMET properties.

  5. Preparation and Characterization of Atactic Poly(vinyl alcohol)/Platinum Nanocomposites by Electrospinning (United States)

    Seok Lyoo, Won; Jae Lee, Young; Wook Cha, Jin; Jae Kim, Min; Woo Joo, Sang; Soon Gal, Yeong; Hwan Oh, Tae; Soo Han, Sung


    Poly(vinyl alcohol) (PVA)/platinum composite nanofibers were successfully prepared by the electrospinning method. Water-based colloidal platinum in a PVA solution was directly mixed without any chemical or structural modifications into PVA polymer fibers to form organic-inorganic composite nanofibers. The PVA/platinum composite nanofibers were characterized by field emission scanning electron microscopy (SEM).

  6. Platinum Publications, December 30, 2016–January 25, 2017 | Poster (United States)

    Platinum Publications are selected from articles by NCI at Frederick scientists published in 42 prestigious science journals. This list represents articles published during the time period shown above, as generated from PubMed. Articles designated as Platinum Highlights are noteworthy articles selected from among the most recently published Platinum Publications.


    Institute of Scientific and Technical Information of China (English)

    HUANG Meiyu; HUANG Li; ZHENG Qingyao; WANG Dianxun; JIANG Yingyan


    Two kinds of polymer-platinum complexes: silica-supported poly-γ-diphenylphosphinopropyl-siloxane-platinum complex and silica-supported polyphenylsilazane-platinum complex, have been found very active and selective in catalyzation of oxidation of methanol to formaldehyde at room temperature and under an atmospheric oxygen pressure. Their catalytic activities are greatly affected by P or N/Pt gram atomic ratio.

  8. 75 FR 77572 - Proposed Revision of Class E Airspace; Platinum AK (United States)


    ... Federal Aviation Administration 14 CFR Part 71 Proposed Revision of Class E Airspace; Platinum AK AGENCY... action proposes to revise Class E airspace at Platinum AK. The creation of a new Standard Instrument Approach Procedure (SIAP) at the Platinum Airport has made this action necessary to enhance safety...

  9. 76 FR 67793 - Notification of Expanded Pricing Grid for Precious Metals Products Containing Platinum and Gold... (United States)


    ... United States Mint Notification of Expanded Pricing Grid for Precious Metals Products Containing Platinum..., 2009, outlining the new pricing methodology for numismatic products containing platinum and gold. Since that time, the price of platinum and gold has increased considerably, and is approaching the...

  10. 40 CFR 440.110 - Applicability; description of the platinum ore subcategory. (United States)


    ... platinum ore subcategory. 440.110 Section 440.110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Platinum Ores Subcategory § 440.110 Applicability; description of the platinum ore subcategory. The provisions of...

  11. Flow Injection Analysis with Electrochemical Detection for Rapid Identification of Platinum-Based Cytostatics and Platinum Chlorides in Water

    Directory of Open Access Journals (Sweden)

    Marketa Kominkova


    Full Text Available Platinum-based cytostatics, such as cisplatin, carboplatin or oxaliplatin are widely used agents in the treatment of various types of tumors. Large amounts of these drugs are excreted through the urine of patients into wastewaters in unmetabolised forms. This phenomenon leads to increased amounts of platinum ions in the water environment. The impacts of these pollutants on the water ecosystem are not sufficiently investigated as well as their content in water sources. In order to facilitate the detection of various types of platinum, we have developed a new, rapid, screening flow injection analysis method with electrochemical detection (FIA-ED. Our method, based on monitoring of the changes in electrochemical behavior of analytes, maintained by various pH buffers (Britton-Robinson and phosphate buffer and potential changes (1,000, 1,100 and 1,200 mV offers rapid and cheap selective determination of platinum-based cytostatics and platinum chlorides, which can also be present as contaminants in water environments.

  12. Flow injection analysis with electrochemical detection for rapid identification of platinum-based cytostatics and platinum chlorides in water. (United States)

    Kominkova, Marketa; Heger, Zbynek; Zitka, Ondrej; Kynicky, Jindrich; Pohanka, Miroslav; Beklova, Miroslava; Adam, Vojtech; Kizek, Rene


    Platinum-based cytostatics, such as cisplatin, carboplatin or oxaliplatin are widely used agents in the treatment of various types of tumors. Large amounts of these drugs are excreted through the urine of patients into wastewaters in unmetabolised forms. This phenomenon leads to increased amounts of platinum ions in the water environment. The impacts of these pollutants on the water ecosystem are not sufficiently investigated as well as their content in water sources. In order to facilitate the detection of various types of platinum, we have developed a new, rapid, screening flow injection analysis method with electrochemical detection (FIA-ED). Our method, based on monitoring of the changes in electrochemical behavior of analytes, maintained by various pH buffers (Britton-Robinson and phosphate buffer) and potential changes (1,000, 1,100 and 1,200 mV) offers rapid and cheap selective determination of platinum-based cytostatics and platinum chlorides, which can also be present as contaminants in water environments.

  13. Oscillatory instabilities in the electrooxidation of borohydride on platinum

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Eduardo G.; Varela, Hamilton, E-mail: [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Instituto de Quimica


    The borohydride ion has been pointed as a promising alternative fuel. Most of the investigation on its electrochemistry is devoted to the electrocatalytic aspects of its electrooxidation on platinum and gold surfaces. Besides the known kinetic limitations and intricate mechanism, our Group has recently found the occurrence of two regions of bi-stability and autocatalysis in the electrode potential during the open circuit interaction of borohydride and oxidized platinum surfaces. Following this previous contribution, the occurrence of more complicated phenomena is here presented: namely the presence of electrochemical oscillations during the electrooxidation of borohydride on platinum in alkaline media. Current oscillations were found to be associated to two distinct instability windows and characterized in the resistance-potential parameter plane. The dynamic features of such oscillations suggest the existence of distinct mechanisms according to the potential region. Previously published results obtained under non-oscillatory regime were used to give some hints on the surface chemistry behind the observed dynamics. (author)

  14. Current View in Platinum Drug Mechanisms of Peripheral Neurotoxicity

    Directory of Open Access Journals (Sweden)

    Alessia Chiorazzi


    Full Text Available Peripheral neurotoxicity is the dose-limiting factor for clinical use of platinum derivatives, a class of anticancer drugs which includes cisplatin, carboplatin, and oxaliplatin. In particular cisplatin and oxaliplatin induce a severe peripheral neurotoxicity while carboplatin is less neurotoxic. The mechanisms proposed to explain these drugs’ neurotoxicity are dorsal root ganglia alteration, oxidative stress involvement, and mitochondrial dysfunction. Oxaliplatin also causes an acute and reversible neuropathy, supposed to be due by transient dysfunction of the voltage-gated sodium channels of sensory neurons. Recent studies suggest that individual genetic variation may play a role in the pathogenesis of platinum drug neurotoxicity. Even though all these mechanisms have been investigated, the pathogenesis is far from clearly defined. In this review we will summarize the current knowledge and the most up-to-date hypotheses on the mechanisms of platinum drug-induced peripheral neurotoxicity.

  15. Preparation of platinum/iridium scanning probe microscopy tips

    DEFF Research Database (Denmark)

    Sørensen, Alexis Hammer; Hvid, U.; Mortensen, M.W.


    for the production of sharp tips. After being etched the tips are ready for use in scanning tunneling microscopes, or they may be bent to form integrated tip/cantilever systems in ordinary commercial atomic force microscopes, being applicable as tapping mode tips and as electrostatic force microscopy tips. ©1999......We report on the development of an etching setup for use in the preparation of platinum/iridium tips for atomic force microscopy and scanning electrostatic force microscopy as well as scanning tunneling microscopy. The etching process is based on a two step electrochemical procedure. The first step....... This mechanism is based on the formation of oxygen and hydrogen at the platinum/iridium electrode when the potential is above the dissociation potential of water (~ 1.23 V) and storage of these products interstitially in the outer layers of the platinum wire. This leads to "microexplosions" that detach fragments...

  16. Platinum-Iridium Alloy Films Prepared by MOCVD

    Institute of Scientific and Technical Information of China (English)

    WEI Yan; CHEN Li; CAI Hongzhong; ZHENG Xu; YANG Xiya; HU Changyi


    Platinum-Iridium alloy films were prepared by MOCVD on Mo substrate using metal-acetylacetonate precursors.Effects of deposition conditions on composition,microstructure and mechanical properties were determined.In these experimental conditions,the purities of films are high and more than 99.0%.The films are homogeneous and monophase solid solution of Pt and Ir.Weight percentage of platinum are much higher than iridium in the alloy.Lattice constant of the alloy changes with the platinum composition.Iridium composition showing an up-down-up trend at the precursor temperature of 190~230℃ and the deposition temperature at 400~550℃.The hardness of Pt-Ir alloys prepared by MOCVD is three times more than the alloys prepared by casting.

  17. Interaction of DNA with Bis(diiminosuccinonitrilo)platinum(Ⅱ)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-Gang; SUN Yuan-Yuan; JIANG Xiao-Ming


    Interaction of DNA with bis(diiminosuccinonitrilo)platinum(Ⅱ) has been studied by UV-visible absorbance spectra, fluorescence spectra and viscosity measurements. The UV-visible absorption spectra of the metal complex exhibit hypochromism with a small blue shift on interaction with DNA. Scatchard plot analyses indicate that the binding sites of the metal complex on DNA are different from those of ethidium bromide. Viscosity experiments reveal that the binding of the metal complex decreases the relative viscosity of DNA. These results suggest that the platinum diimine complex interact with DNA by surface binding. These studies are helpful for us to understand the action mechanism of bis(diiminosuccinonitrilo)platinum(Ⅱ) as a potential photodynamic therapeutic agent, and further to develop it.

  18. Synthesis and Electrocatalytic Performance of BDD-Supported Platinum Nanoparticles (United States)

    Lyu, Xiao; Hu, Jingping; Foord, John S.; Lou, Changsheng; Zhang, Weiqiang


    Platinum nanoparticles were deposited on boron-doped diamond substrate by electroless method without pre-activation. The mechanism of this deposition is a galvanic process along with a chemical process. Platinum particles are in nanoscale with diameter around 30-50 nm and height of around 3 nm observed from AFM and SEM images. The electrochemical activity of Pt nanoparticles was evaluated by cyclic voltammograms of hydrogen desorption process in 0.5 M H2SO4. The deposited platinum shows great stability in subsequent cycling in sulfuric acid and exhibits a high selectivity toward H2O2 detection in the range of 1 to 400 μM compared with those produced by electrochemical deposition.

  19. Decitabine reactivated pathways in platinum resistant ovarian cancer. (United States)

    Fang, Fang; Zuo, Qingyao; Pilrose, Jay; Wang, Yinu; Shen, Changyu; Li, Meng; Wulfridge, Phillip; Matei, Daniela; Nephew, Kenneth P


    Combination therapy with decitabine, a DNMTi and carboplatin resensitized chemoresistant ovarian cancer (OC) to platinum inducing promising clinical activity. We investigated gene-expression profiles in tumor biopsies to identify decitabine-reactivated pathways associated with clinical response. Gene-expression profiling was performed using RNA from paired tumor biopsies before and 8 days after decitabine from 17 patients with platinum resistant OC. Bioinformatic analysis included unsupervised hierarchical-clustering, pathway and GSEA distinguishing profiles of "responders" (progression-free survival, PFS>6 months) and "non-responders" (PFSdecitabine (TGF-β and Hh). Gene-expression profiling identified specific pathways altered by decitabine and associated with platinum-resensitization and clinical benefit in OC. Our data could influence patient stratification for future studies using epigenetic therapies.

  20. Water quality - Evaluation of the aerobic biodegradability of organic compounds at low concentrations. Part 1: Shake-flask batch test with surface water or suface water/sediment suspensions. ISO 14592-1

    DEFF Research Database (Denmark)

    Nyholm, Niels; Pagga, U.

    environment (pelagic test) or to surface water with suspended solids or sediments added to obtain a level of 0,1 g/l to 1 g/l dry mass (suspended sediment test) to simulate a water-to-sediment interface or a water body with resuspended sediment material. ISO 14592-1:2002 is applicable to organic test...... compounds present in lower concentrations (normally below 100 micrograms per litre) than those of natural carbon substrates also present in the system. Under these conditions, the test compounds serve as a secondary substrate and the kinetics for biodegradation would be expected to be first order (non...

  1. Investigation of mechanical and structural characteristics of platinum and palladium at high temperatures

    Directory of Open Access Journals (Sweden)

    Trumic, Biserka T.


    Full Text Available In order to broaden future application of products based on platinum and palladium a comparative analysis of their high-temperature mechanical properties was performed. Platinum and palladium are of great importance and are widely used in chemical industry, electronics, for making laboratory dishes, to name a few. Mechanical properties of pure metals, such as: tensile strength, creep rate and rupture time were investigated using universal testing machine for tensile testing of materials. Microstructure of samples was investigated by optical microscopy. Based on obtained results it can be concluded that the platinum, compared to palladium, is superior for high-temperature applications.Se realiza un estudio comparativo de las propiedades mecánicas a alta temperatura del platino y paladio, con el fin de ampliar las aplicaciones de los productos basados en estos metales. El platino y el paladio son de gran importancia y se utilizan ampliamente en la industria química, electrónica y para la fabricación de placas de laboratorio, entre otras aplicaciones. Se estudiaron las siguientes propiedades mecánicas de los metales puros: resistencia a la tracción, velocidad de fluencia y tiempo de rotura bajo condiciones de fluencia. Para esas investigaciones se utilizó una máquina universal de ensayos para realizar los ensayos de tracción. La micro- estructura fue investigada por microscopía óptica. Basándose en los resultados obtenidos, se puede concluir que el platino, en comparación con el paladio, presenta mejores prestaciones para aplicaciones a alta temperatura.

  2. A germline predictive signature of response to platinum chemotherapy in esophageal cancer. (United States)

    Rumiato, Enrica; Boldrin, Elisa; Malacrida, Sandro; Battaglia, Giorgio; Bocus, Paolo; Castoro, Carlo; Cagol, Matteo; Chiarion-Sileni, Vanna; Ruol, Alberto; Amadori, Alberto; Saggioro, Daniela


    Platinum-based neoadjuvant therapy is the standard treatment for esophageal cancer (EC). At present, no reliable response markers exist, and patient therapeutic outcome is variable and very often unpredictable. The aim of this study was to understand the contribution of host constitutive DNA polymorphisms in discriminating between responder and nonresponder patients. DNA collected from 120 EC patients treated with platinum-based neoadjuvant chemotherapy was analyzed using drug metabolism enzymes and transporters (DMET) array platform that interrogates polymorphisms in 225 genes of drug metabolism and disposition. Four gene variants of DNA repair machinery, 2 in ERCC1 (rs11615; rs3212986), and 2 in XPD (rs1799793; rs13181) were also studied. Association analysis was performed with pTest software and corrected by permutation test. Predictive models of response were created using the receiver-operating characteristics curve approach and adjusted by the bootstrap procedure. Sixteen single nucleotide polymorphisms (SNPs) of the DMET array resulted significantly associated with either good or poor response; no association was found for the 4 variants mapping in DNA repair genes. The predictive power of 5 DMET SNPs mapping in ABCC2, ABCC3, CYP2A6, PPARG, and SLC7A8 genes was greater than that of clinical factors alone (area under the curve [AUC] = 0.74 vs 0.62). Interestingly, their combination with the clinical variables significantly increased the predictivity of the model (AUC = 0.78 vs 0.62, P = 0.0016). In conclusion, we identified a genetic signature of response to platinum-based neoadjuvant chemotherapy in EC patients. Our results also disclose the potential benefit of combining genetic and clinical variables for personalized EC management.

  3. Efficient Dye-Sensitized Solar Cells Made from High Catalytic Ability of Polypyrrole@Platinum Counter Electrode


    Ma, Xingping; Yue, Gentian; Wu, Jihuai; Lan, Zhang


    Polypyrrole@platinum (PPy@Pt) composite film was successfully synthesized by using a one-step electrochemical method and served as counter electrode (CE) for efficient dye-sensitized solar cells (DSSCs). The PPy@Pt CE with one-dimensional structure exhibited excellent electrocatalytic activity and superior charge transfer resistance for I−/I3 − electrolyte after being the cyclic voltammetry and electrochemical impedance spectroscopy tested. The photocurrent-photovoltage curves were further us...

  4. Assessment of the time-dependent inhibition (TDI) potential of test compounds with human liver microsomes by IC50 shift method using a nondilution approach. (United States)

    de Ron, Lian; Rajaraman, Ganesh


    Time-dependent inhibition (TDI) of hepatic cytochrome P450 (CYP) enzymes is increasingly implicated in the majority of clinically relevant drug-drug interactions (DDIs). A time-dependent inhibitor or its reactive metabolite irreversibly inactivates CYP enzymes, thereby inhibiting the metabolism of other drugs. As the majority of marketed drugs are metabolized by CYP enzymes, their inhibition has important clinical consequences, such as in decreasing the metabolic clearance of a co-administered drug (victim drug). This could be life threatening, as such an effect narrows the therapeutic index for drugs such as warfarin and other potentially toxic agents. Therefore, it is essential to examine new chemical entities for their potential to cause TDI to minimize adverse drug reactions during human studies and use. This unit presents an in vitro procedure utilizing a nondilution method in human liver microsomes for determining the TDI potential of test compounds.

  5. Characterization of High-Temperature Platinum Resistance Thermometers at Silver Point (United States)

    Widiatmo, J. V.; Harada, K.; Yamazawa, K.


    Thermal cycling tests have been conducted on various types of high-temperature standard platinum resistance thermometers (HTSPRTs) that are commercially available at present. The investigated HTSPRTs have nominal resistance values at the triple point of water (TPW) of 0.25 Ω , 0.6 Ω , 2.5 Ω , and 3 Ω . They vary in terms of the platinum wiring on their sensor supports (frames) and the support materials, their protective sheaths and their sealing materials. Ten HTSPRTs were evaluated with regard to their stability during use at silver-point temperature or above. This evaluation included a thermal cycling test following various setup patterns, which indicated that each HTSPRT has its own preferred pattern. The stability test results for eight of ten HTSPRTs during four silver-point realizations, based on this pattern, yielded a maximum discrepancy in the resistance ratio of within ± 6 mK. The maximum resistance discrepancy at TPW was ± 2.7 mK.

  6. Engineering Customized TALENs Using the Platinum Gate TALEN Kit. (United States)

    Sakuma, Tetsushi; Yamamoto, Takashi


    Among various strategies for constructing customized transcription activator-like effector nucleases (TALENs), the Golden Gate assembly is the most widely used and most characterized method. The principle of Golden Gate assembly involves cycling reactions of digestion and ligation of multiple plasmids in a single tube, resulting in PCR-, fragmentation-, and purification-free concatemerization of DNA-binding repeats. Here, we describe the protocols for Golden Gate assembly-based TALEN construction using the Platinum Gate TALEN Kit, which allows generation of highly active Platinum TALENs.

  7. Distribution of platinum and cobalt atoms in a bimetallic nanoparticle (United States)

    Chui, Yu Hang; Chan, Kwong-Yu


    Molecular dynamics simulations are performed to investigate the atomic distribution and the structure of platinum-cobalt nanoparticles. Heating and cooling techniques are applied before getting equilibrated structures at 298 K. Both crystalline (fcc) and amorphous structures are partly observed depending on cooling rates. The atomic distributions in different regions of a bimetallic nanoparticle are analyzed. Although platinum tends to occupy surface and near-surface sites of the bimetallic nanoparticle, a complete segregation to form a core-shell structure is not observed.

  8. Addition of platinum and silver nanoparticles to toughen dental porcelain. (United States)

    Fujieda, Tokushi; Uno, Mitsunori; Ishigami, Hajime; Kurachi, Masakazu; Wakamatsu, Nobukazu; Doi, Yutaka


    Several studies have investigated toughening porcelain that is layered over a frame or a core. The introduction of residual compressive stress to the surface of porcelain has been shown to be effective to strengthen it. In the present study, nanoparticles of precious metals of silver and platinum (rather than non-precious metals) were used to evaluate if they could increase the fracture resistance of porcelain. The addition of silver and platinum nanoparticles was found to improve the mechanical properties of porcelain since it increased both the Young's modulus and the fracture toughness of commercial porcelain.

  9. Synthesis of platinum nanoparticle electrocatalysts by atomic layer deposition (United States)

    Lubers, Alia Marie

    Demand for energy continues to increase, and without alternatives to fossil fuel combustion the effects on our environment will become increasingly severe. Fuel cells offer a promising improvement on current methods of energy generation; they are able to convert hydrogen fuel into electricity with a theoretical efficiency of up to 83% and interface smoothly with renewable hydrogen production. Fuel cells can replace internal combustion engines in vehicles and are used in stationary applications to power homes and businesses. The efficiency of a fuel cell is maximized by its catalyst, which is often composed of platinum nanoparticles supported on carbon. Economical production of fuel cell catalysts will promote adoption of this technology. Atomic layer deposition (ALD) is a possible method for producing catalysts at a large scale when employed in a fluidized bed. ALD relies on sequential dosing of gas-phase precursors to grow a material layer by layer. We have synthesized platinum nanoparticles on a carbon particle support (Pt/C) by ALD for use in proton exchange membrane fuel cells (PEMFCs) and electrochemical hydrogen pumps. Platinum nanoparticles with different characteristics were deposited by changing two chemistries: the carbon substrate through functionalization; and the deposition process by use of either oxygen or hydrogen as ligand removing reactants. The metal depositing reactant was trimethyl(methylcyclopentadienyl)platinum(IV). Functionalizing the carbon substrate increased nucleation during deposition resulting in smaller and more dispersed nanoparticles. Use of hydrogen produced smaller nanoparticles than oxygen, due to a gentler hydrogenation reaction compared to using oxygen's destructive combustion reaction. Synthesized Pt/C materials were used as catalysts in an electrochemical hydrogen pump, a device used to separate hydrogen fuel from contaminants. Catalysts deposited by ALD on functionalized carbon using a hydrogen chemistry were the most

  10. Chemotherapy-induced peripheral neuropathy in patients treated with taxanes and platinum derivatives

    DEFF Research Database (Denmark)

    Ewertz, Marianne; Qvortrup, Camilla; Eckhoff, Lise


    BACKGROUND: Chemotherapy with taxanes and platinum compounds has resulted in substantial survival benefits both in adjuvant and metastatic settings. However, as a side effect, such chemotherapy may cause peripheral neuropathy (CIPN) which may result in discontinuation of treatment......, and if it persists after treatment completion, has a negative impact on quality of life (QoL). RESULTS: Symptoms of CIPN are sensory, like pain, numbness, and tingling, typically located in the hands and feet. For oxaliplatin, there is an acute form of CIPN, resulting in paraesthesias in the mouth and throat during......-induced neuropathy is irreversible, CIPN induced by taxanes may persist for several years in about 30% of patients. Evidence from the literature is suggestive that CIPN is likely to be negatively associated with QoL. No agents have been identified to be recommended for the prevention of CIPN. For treatment of CIPN...

  11. Role of copper transporters in the uptake and efflux of platinum containing drugs. (United States)

    Safaei, Roohangiz


    Cellular mechanisms for the uptake, intracellular distribution and efflux of the platinum (Pt) containing compounds cisplatin (DDP), carboplatin (CBDCA) and oxaliplatin (LOHP) are unknown. Current data suggest that specialized transporters/carriers mediate the transport of Pt drugs across the cellular membranes. Specific roles for the copper (Cu) transporters CTR1, ATP7A and ATP7B have been demonstrated during recent years. The finding that in cultured cells and tumor samples a correlation can be found between the expression of Cu transporters and the degree of the acquired resistance to Pt drug suggests that the Cu transporters are important constituents of the program that regulates sensitivity to Pt drugs. A model is presented that describes the function of Cu transporters in the regulation of Pt drug uptake and efflux.

  12. MEA 86 Compound data (United States)

    U.S. Environmental Protection Agency — This data file contains the full raw parameter data for the 86 compounds tested in the developmental MEA assay, as well as Area Under the Curve (AUC) calculations...

  13. Effects of Cluster Size on Platinum-Oxygen Bonds Formation in Small Platinum Clusters (United States)

    Oemry, Ferensa; Padama, Allan Abraham B.; Kishi, Hirofumi; Kunikata, Shinichi; Nakanishi, Hiroshi; Kasai, Hideaki; Maekawa, Hiroyoshi; Osumi, Kazuo; Sato, Kaoru


    We present the results of density functional theory calculation in oxygen dissociative adsorption process on two types of isolated platinum (Pt) clusters: Pt4 and Pt10, by taking into account the effect of cluster reconstruction. The strength of Pt-Pt bonds in the clusters is mainly defined by d-d hybridization and interstitial bonding orbitals (IBO). Oxygen that adsorbed on the clusters is weakening the IBO and thus inducing geometry reconstruction as occurred in Pt10 cluster. However, cluster that could undergo structural deformation is found to promote oxygen dissociation with no energy barrier. The details show that maintaining well-balanced of attractive and repulsive (Hellmann-Feynman) forces between atoms is considered to be the main key to avoid any considerable rise of energy barrier. Furthermore, a modest energy barrier that gained in Pt4 cluster is presumed to be originate from inequality of intramolecular forces between atoms.

  14. Preparation of MgO supported platinum nanoparticle catalyst using toluene dispersed platinum sol (United States)

    Seth, Jhumur; Nepak, Devadutta; Chaudhari, Vijay R.; Prasad, Bhagavatula L. V.


    An effective way of anchoring Pt nanoparticles on MgO using toluene dispersed platinum nanoparticles (Pt-NPs) as one of the ingredient is demonstrated. The usage of particles dispersed in toluene allows the retention of size and size distribution of preformed Pt-NPs even after deposition on MgO support with high active surface area, which is crucial for heterogeneous catalysis. The catalyst thus prepared, displayed selective hydrogenation of cinnamaldehyde to cinnamyl alcohol with high turn on frequency (TOF - 105 h-1) with respect to the total Pt content. We attribute this efficient catalytic performance to the uniform distribution and deposition of Pt on the active MgO support and its better accessible surface as evidenced by the cyclic-voltammetry results.

  15. Linker design for the modular assembly of multifunctional and targeted platinum(ii)-containing anticancer agents. (United States)

    Ding, S; Bierbach, U


    A versatile and efficient modular synthetic platform was developed for assembling multifunctional conjugates and targeted forms of platinum-(benz)acridines, a class of highly cytotoxic DNA-targeted hybrid agents. The synthetic strategy involved amide coupling between succinyl ester-modified platinum compounds (P1, P2) and a set of 11 biologically relevant primary and secondary amines (N1-N11). To demonstrate the feasibility and versatility of the approach, a structurally and functionally diverse range of amines was introduced. These include biologically active molecules, such as rucaparib (a PARP inhibitor), E/Z-endoxifen (an estrogen receptor antagonist), and a quinazoline-based tyrosine kinase inhibitor. Micro-scale reactions in Eppendorf tubes or on 96-well plates were used to screen for optimal coupling conditions in DMF solution with carbodiimide-, uronium-, and phosphonium-based compounds, as well as other common coupling reagents. Reactions with the phosphonium-based coupling reagent PyBOP produced the highest yields and gave the cleanest conversions. Furthermore, it was demonstrated that the chemistry can also be performed in aqueous media and is amenable to parallel synthesis based on multiple consecutive reactions in DMF in a "one-tube" format. In-line LC-MS was used to assess the stability of the conjugates in physiologically relevant buffers. Hydrolysis of the conjugates occurs at the ester moiety and is facilitated by the aquated metal moiety under low-chloride ion conditions. The rate of ester cleavage greatly depends on the nature of the amine component. Potential applications of the linker technology are discussed.

  16. Effect of Rotation Rate on the Formation of Platinum-modified Polyaniline Film and Electrocatalytic Oxidation of Methanol

    Institute of Scientific and Technical Information of China (English)

    Qiu Hong LI; Lin NIU; Chang Qiao ZHANG; Feng Hua WEI; Hu ZHANG


    The oxidation of methanol was investigated on platinum-modified polyaniline electrode. Changes in the electrode rotation rates (Ω) during platinum electrodeposition remarkably affect the formation and distribution of platinum in the polymer matrix and consequently lead to different currents of methanol oxidation. The results show that platinum loading is proportional to rotation ratesΩ1/2.

  17. Physical and electrochemical study of platinum thin films deposited by sputtering and electrochemical methods

    Energy Technology Data Exchange (ETDEWEB)

    Quinones, C. [Universidad de Cartagena, Cartagena de Indias (Colombia); Departamento de Quimica, Universidad Nacional de Colombia, Cra. 30 No 45-03, Bogota (Colombia); Vallejo, W., E-mail: [Departamento de Quimica, Universidad Nacional de Colombia, Cra. 30 No 45-03, Bogota (Colombia); Mesa, F. [Departamento de Ciencias Basicas, Universidad Libre, Carrera 70 No 53-40, Bogota (Colombia)


    In this work platinum thin films deposited by sputtering and electrochemical methods were characterized through physical and electrochemical analysis. The as-grown platinum thin films were characterized through X-ray diffraction (XRD), atomic force microscopy (AFM); scanning electronic microscopy (SEM) and through electrochemical impedance spectroscopy (EIS) measurements. Structural studies indicated that platinum thin films were polycrystalline. Morphological characteristics were significantly affected by the substrate type and synthesis method. Finally the EIS analysis indicated that platinum films were electrochemically stable and present both low resistance of charge transfer and low series resistance; the equivalent circuit of platinum interface has been proposed.

  18. In vitro and in vivo anti-tumor effects of selected platinum(IV) and dinuclear platinum(II) complexes against lung cancer cells. (United States)

    Arsenijevic, Milos; Milovanovic, Marija; Jovanovic, Snezana; Arsenijevic, Natalija; Markovic, Bojana Simovic; Gazdic, Marina; Volarevic, Vladislav


    In the present study, cytotoxic effects of cisplatin, the most usually used chemotherapeutic agent, were compared with new designed platinum(IV) ([PtCl4(en)] (en = ethylenediamine) and [PtCl4(dach)]) (dach = (±)-trans-1,2-diaminocyclohexane) and platinum(II) complexes ([{trans-Pt(NH3)2Cl}2(μ-pyrazine)](ClO4)2 (Pt1), [{trans-Pt(NH3)2Cl}2(μ-4,4'-bipyridyl)](ClO4)2DMF(Pt2),[{trans-Pt(NH3)2Cl}2(μ-1,2-bis(4pyridyl)ethane)](ClO4)2 (Pt3)), in vitro and in vivo against human and murine lung cancer cells, to determine anti-tumor potential of newly synthesized platinum-based drugs in the therapy of lung cancer. Results obtained by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide], Lactate dehydrogenase and Annexin V/Propidium Iodide assays showed that, among all tested complexes, [PtCl4(en)] had the highest cytotoxicity against human and murine lung carcinoma cells in vitro. [PtCl4(en)] showed significantly higher cytotoxicity then cisplatin in all tested concentrations, mainly by inducing apoptosis in lung cancer cells. [PtCl4(en)] was well tolerated in vivo. Clinical signs of [PtCl4(en)]-induced toxicity, such as changes in food, water consumption or body weight, nephrotoxicity or hepatotoxicity was not observed in [PtCl4(en)]-treated mice. [PtCl4(en)] managed to increase presence of CD45+ leukocytes, including F4/80+ macrophages, CD11c+ dendritic cells, CD4+ helper and CD8+ cytotoxic T cells (CTLs) in the lungs, cytotoxic NK, NKT and CTLs in the spleens of tumor bearing mice, resulting with reduction of metastatic lesions in the lungs, indicating its potential to stimulate anti-tumor immune response in vivo. Due to its anti-tumor cytotoxicity, biocompatibility, and potential for stimulation of anti-tumor immune response, [PtCl4(en)] may be a good candidate for further testing in the field of medicinal chemistry.

  19. Recent strikes in South Africa’s platinum-group metal mines: effects upon world platinum-group metal supplies (United States)

    Yager, Thomas R.; Soto-Viruet, Yadira; Barry, James J.


    The recent labor disputes over wages and working conditions that have affected South Africa’s three leading platinum-group metal (PGM) producers have affected an industry already plagued by market pressures and labor unrest and raised the specter of constraints in the world’s supply of these metals. Although low demand for these metals in 2011 and 2012 helped to offset production losses of recent years, and particularly those losses caused by the strikes in 2012, a prolonged resumption of strikes could cause severe shortages of iridium, platinum, rhodium, ruthenium, and, to a lesser extent, palladium.

  20. [Comparison of the effectiveness of platinum-based chemotherapy versus non-platinum-based chemotherapy for triple-negative breast cancer with metastases confined to the lungs]. (United States)

    Hong, Ruoxi; Ma, Fei; Shi, Xiuqing; Li, Qing; Zhang, Pin; Yuan, Peng; Wang, Jiayu; Fan, Ying; Cai, Ruigang; Li, Qiao; Xu, Binghe


    To compare the effect of first-line treatment with platinum-based chemotherapy and non-platinum-based chemotherapy in patients with lung metastases from triple negative breast cancer (TNBC). Sixty-five eligible patients were divided into platinum-treated group and non-platinum-treated group according to the first-line therapy. Factors predicting the chemotherapeutic efficacy included overall survival (OS), progression-free survival (PFS) and objective response (OR). In the platinum-treated group of 32 patients, 2 cases (6.3%) achieved CR, 16 cases (50.0%) achieved PR, 11 (34.4%) cases achieved SD, and 3 patients (9.4%) achieved PD. In the non-platinum-treated group of 33 patients, 2 cases (6.1%) achieved CR, 6 cases (18.2%) achieved PR, 16 cases (48.5%) achieved SD, and 9 cases (27.3%) achieved PD. Median PFS was significantly longer in the platinum-treated group than in the non-platinum-treated group (10 months vs. 6.0 months, P = 0.012), and OS was also improved (32 months vs. 22 months, P = 0.006). Multivariate analysis of several factors including local-regional lymph node involvement, lung metastasis-related symptoms, first-line platinum-based chemotherapy, disease-free interval, size and number of lung lesions, showed that first-line platinum-based chemotherapy was an independent prognostic factor for TNBC patients with lung metastases. Compared with non-platinum-based chemotherapy, the first-line platinum-based chemotherapy can improve PFS and OS in TNBC patients with metastases confined to the lungs.


    Keil, H; Wasserman, D; Dawson, C R


    1. Additional evidence is presented in support of the view which postulates a close chemical and biologic relation between the active ingredients in poison ivy and Japan lac. 2. Biologic evidence, based on the use of the patch test in man, is presented in support of the view that the active ingredient in poison ivy is a catechol derivative with a long, unsaturated side-chain in the 3-position. 3. Of the catechol compounds and derivatives studied, group reactions in patients sensitive to poison ivy leaves or extract were exhibited by the following compounds: 3-pentadecyl catechol (100 per cent of 21 cases), 4-pentadecyl catechol (38 per cent of 21 cases), "urushiol" dimethyl ether (33 per cent of 33 cases), 3-pentadecenyl-1'-veratrole (21 per cent of 14 cases), 3-methyl catechol (14 per cent of 21 cases), and hydrourushiol dimethyl ether (10 per cent of 20 cases). It has been found that 3-geranyl catechol shows a practically constant group reactivity in persons sensitive to poison ivy. 4. The uniformly positive group reaction to 3-pentadecyl catechol is notable since this substance possesses a saturated side-chain, whereas the active ingredient in poison ivy is known to have an unsaturated side-chain. 5. The group reactivity was not restricted to the 3-position, for in some instances 4-pentadecyl catechol also gave group reactions which, however, were less intense and less frequent than those shown by 3-pentadecyl catechol. This indicates that in some cases a long side-chain in the 4 position may be effective in producing group specific reactions. 6. Only an occasional person showed sensitiveness to 3-methyl catechol (short side-chain), and in one instance the group reactivity appeared to be specific for the 3-position. 7. The position of the side-chain in the catechol configuration has some bearing on the degree and incidence of group reactions in persons hypersensitive to poison ivy. 8. Evidence is presented to indicate that the introduction of double bonds in the

  2. Conjugation of platinum(IV) complexes with chlorambucil to overcome cisplatin resistance via a "joint action" mode toward DNA. (United States)

    Qin, Xiaodong; Fang, Lei; Chen, Feihong; Gou, Shaohua


    Two platinum(IV) complexes were designed and prepared by conjugation of cisplatin and oxaliplatin units with a DNA-damaging agent, chlorambucil, respectively. By taking a joint action to enhance the damage of DNA, the conjugates displayed potent antitumor activity against all the tested cancer cell lines comparable to cisplatin and oxaliplatin, and notably could overcome cisplatin resistance at certain degree. Complex 4, a hybrid of cisplatin and chlorambucil, arrested the cell cycle at the S and G2 phases, distinctive from those of cisplatin and oxaliplatin. Apoptosis studies revealed that complex 4 could induce cell apoptosis significantly in both SGC7901 and SGC7901/CDDP cells. Moreover, further investigation indicated that complex 4 suppressed the drug resistance by the improvement of the platinum uptake and the inhibition of PRAP-1 protein. These results show that the "joint action" on DNA is an effective strategy to overcome cisplatin resistance. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  3. Characterization of the properties of stationary phases for liquid chromatography in aqueous mobile phases using aromatic sulphonic acids as the test compounds. (United States)

    Jandera, P; Bocian, S; Molíková, M; Buszewski, B


    We investigated the effects of the concentration of naphthalene sulphonic acids (NSAs) as anionic test compounds in the injected sample and of the salt additives to the mobile phase on ion-exclusion. The retention behaviour of NSAs sensitively reflects even minor changes in the ionic and hydrophobic interactions and can be useful for predicting the effects of the stationary phases in reversed-phase chromatography of polar and ionic compounds, both small ones and biopolymers, e.g., oligonucleotides. We studied chromatographic properties of several stationary phases intended for separations in aqueous mobile phases: a C18 column end-capped with polar hydrophilic groups, a densely bonded C8 column doubly end-capped with short alkyl groups, a short alkyl stationary phase designed to keep full pore accessibility in highly-aqueous mobile phases and a Bidentate column with "bridged" C18 groups attached to the silica hydride support. The chemistry and pore structure of various types of column packing materials and of the salt additives to the mobile phase affect the proportion of the pore volume non-accessible to anions due to ion-exclusion and consequently the peak asymmetry and hydrophobic selectivity in reversed-phase chromatography of organic acids. We also addressed the problems connected with the determination of column hold-up volume in aqueous mobile phases. The accessibility of the stationary phase for anionic compounds in contact with the sample zone is affected by ion-exclusion due to repulsive interactions with the negatively charged surface in the pores of the stationary phase. The accessible part of the stationary phase increases and consequently the migration velocity along the column decreases with increasing concentration of the sample in the zone moving along the column. Because of a limited access to the stationary phase, its capacity can be easily overloaded. The combination of the column overload and ion-exclusion effects may result in fronting or

  4. How displaced migratory birds could use volatile atmospheric compounds to find their migratory corridor? A test using a particle dispersion model.

    Directory of Open Access Journals (Sweden)

    Kamran Safi


    Full Text Available Olfaction represents an important sensory modality for navigation of both homing pigeons and wild birds. Experimental evidence in homing pigeons showed that airborne volatile compounds carried by the winds at the home area are learned in association with wind directions. When displaced, pigeons obtain information on the direction of their displacement using local odours at the release site. Recently, the role of olfactory cues in navigation has been reported also for wild birds during migration. However, the question whether wild birds develop an olfactory navigational map similar to that described in homing pigeons or, alternatively, exploit the distribution of volatile compounds in different manners for reaching the goal is still an open question. Using an interdisciplinary approach, we evaluate the possibilities of reconstructing spatio-temporally explicit aerosol dispersion at large spatial scales using the particle dispersion model FLEXPART. By combining atmospheric information with particle dispersion models, atmospheric scientists predict the dispersion of pollutants for example, after nuclear fallouts or volcanic eruptions or wildfires, or in retrospect reconstruct the origin of emissions such as aerosols. Using simple assumptions, we reconstructed the putative origin of aerosols traveling to the location of migrating birds. We use the model to test whether the putative odour plume could have originated from an important stopover site. If the migrating birds knew this site and the associated plume from previous journeys, the odour could contribut to the reorientation towards the migratory corridor, as suggested for the model scenario in displaced Lesser black-backed gulls migrating from Northern Europe into Africa.

  5. Single-Atom Catalyst of Platinum Supported on Titanium Nitride for Selective Electrochemical Reactions. (United States)

    Yang, Sungeun; Kim, Jiwhan; Tak, Young Joo; Soon, Aloysius; Lee, Hyunjoo


    As a catalyst, single-atom platinum may provide an ideal structure for platinum minimization. Herein, a single-atom catalyst of platinum supported on titanium nitride nanoparticles were successfully prepared with the aid of chlorine ligands. Unlike platinum nanoparticles, the single-atom active sites predominantly produced hydrogen peroxide in the electrochemical oxygen reduction with the highest mass activity reported so far. The electrocatalytic oxidation of small organic molecules, such as formic acid and methanol, also exhibited unique selectivity on the single-atom platinum catalyst. A lack of platinum ensemble sites changed the reaction pathway for the oxygen-reduction reaction toward a two-electron pathway and formic acid oxidation toward direct dehydrogenation, and also induced no activity for the methanol oxidation. This work demonstrates that single-atom platinum can be an efficient electrocatalyst with high mass activity and unique selectivity.

  6. Convection-enhancement delivery of platinum-based drugs and Lipoplatin™ to optimize the concomitant effect with radiotherapy in F98 glioma rat model (United States)

    Shi, Minghan; Fortin, David; Sanche, Léon; Paquette, Benoit


    The prognosis for patients with glioblastoma remains poor with current treatments. Although platinum based drugs are sometimes offered at relapse, their efficacy in this setting is still disputed. In this study, we use convection-enhanced delivery (CED) to deliver the platinum-based drugs (cisplatin, carboplatin, and Lipoplatin™-liposomal formulation of cisplatin) directly into the tumor of F98 glioma-bearing rats that were subsequently treated with γ radiation (15 Gy). CED increased by factors varying between 17 and 111, the concentration of these platinum-based drugs in the brain tumor compared to intra-venous (i.v.) administration, and by 9- to 34-fold, when compared to intra-arterial (i.a.) administration. Furthermore, CED resulted in a better systemic tolerance to platinum drugs compared to their i.a. injection. Among the drugs tested, carboplatin showed the highest maximum tolerated dose (MTD). Treatment with carboplatin resulted in the best median survival time (MeST) (38.5 days), which was further increased by the addition of radiotherapy (54.0 days). Although the DNA-bound platinum adduct were higher at 4 h after CED than 24 h for carboplatin group, combination with radiotherapy led to similar improvement of median survival time. However, less toxicity was observed in animals irradiated 24 h after CED-based chemotherapy. In conclusion, CED increased the accumulation of platinum drugs in tumor, reduced the toxicity, and resulted in a higher median survival time. The best treatment was obtained in animals treated with carboplatin and irradiated 24 h later. PMID:25784204

  7. Convection-enhancement delivery of platinum-based drugs and Lipoplatin(TM) to optimize the concomitant effect with radiotherapy in F98 glioma rat model. (United States)

    Shi, Minghan; Fortin, David; Sanche, Léon; Paquette, Benoit


    The prognosis for patients with glioblastoma remains poor with current treatments. Although platinum-based drugs are sometimes offered at relapse, their efficacy in this setting is still disputed. In this study, we use convection-enhanced delivery (CED) to deliver the platinum-based drugs (cisplatin, carboplatin, and Lipoplatin(TM) - liposomal formulation of cisplatin) directly into the tumor of F98 glioma-bearing rats that were subsequently treated with γ radiation (15 Gy). CED increased by factors varying between 17 and 111, the concentration of these platinum-based drugs in the brain tumor compared to intra-venous (i.v.) administration, and by 9- to 34-fold, when compared to intra-arterial (i.a.) administration. Furthermore, CED resulted in a better systemic tolerance to platinum drugs compared to their i.a. injection. Among the drugs tested, carboplatin showed the highest maximum tolerated dose (MTD). Treatment with carboplatin resulted in the best median survival time (MeST) (38.5 days), which was further increased by the addition of radiotherapy (54.0 days). Although the DNA-bound platinum adduct were higher at 4 h after CED than 24 h for carboplatin group, combination with radiotherapy led to similar improvement of median survival time. However, less toxicity was observed in animals irradiated 24 h after CED-based chemotherapy. In conclusion, CED increased the accumulation of platinum drugs in tumor, reduced the toxicity, and resulted in a higher median survival time. The best treatment was obtained in animals treated with carboplatin and irradiated 24 h later.

  8. Efficacy analysis of two drugs consisting platinum combined with first-line chemotherapeutics regimens on 117 elderly patients with advanced non-small cell lung carcinoma

    Directory of Open Access Journals (Sweden)

    Li-li ZHANG


    Full Text Available Objective To investigate the therapeutic effects of Gemcitabine(GEM, Vinorelbine(NVB,Paclitaxel(TAX and other first-line chemotherapeutics plus platinum containing drugs on the elderly patients with advanced non-small cell lung cancer(NSCLC who had undergone surgery, and analyze the clinicopathological factors influencing the prognosis. Methods One hundred and seventeen advanced NSCLC patients aged 60 or over were treated with GP(GEM+platinum, or NP(NVB+platinum, or TP(TAX+platinum, or other first-line chemotherapeutics plus platinum(OCP after surgery, and their clinical data were then retrospectively studied to look for the relationship of patients' prognosis to clinicopathological factors(gender, operation methods, pathologicaltypes, differentiation, clinical stages.The survival curve was plotted with Kaplan-Meier method, hypothesis test was performed by log-rank, and the independent prognostic factors were screened with Cox proportional hazards regression model. Results Theone-, three- and five-year survival rates of the 117 patients were 47.23%,17.52% and 8.05%, respectively. The progression free survival(PFS of GP, NP, TP and OCP groups were 6.0, 5.2, 6.1 and5.5 months(P>0.05, respectively. The median progression free survival was 5.7 months. Univariate and multivariate analysis showed that the differentiated degrees and clinical stages of elderly NSCLC patients were the independent prognostic factors. Conclusions Clinicopathological factors(differentiated degree andclinical stages are closely related to one-, three- and five-year survival rates of advanced NSCLC in elderly patients who received treatment of first-line chemotherapeutics plus platinum. However, the efficacy ofGP, NP, TP or OCP shows no significant difference.

  9. A Density Functional Study of Bare and Hydrogenated Platinum Clusters

    CERN Document Server

    Sebetci, A


    We perform density functional theory calculations using Gaussian atomic-orbital methods within the generalized gradient approximation for the exchange and correlation to study the interactions in the bare and hydrogenated platinum clusters. The minimum-energy structures, binding energies, relative stabilities, vibrational frequencies and the highest occupied and lowest unoccupied molecular-orbital gaps of Pt_nH_m (n=1-5, m=0-2) clusters are calculated and compared with previously studied pure platinum and hydrogenated platinum clusters. We investigate any magic behavior in hydrogenated platinum clusters and find that Pt_4H_2 is more stable than its neighboring sizes. Our results do not agree with a previous conclusion that 3D geometries of Pt tetramer and pentamer are unfavored. On the contrary, the lowest energy structure of Pt_4 is found to be a distorted tetrahedron and that of Pt_5 is found to be a bridge site capped tetrahedron which is a new global minimum for Pt_5 cluster. The successive addition of H ...

  10. In situ measurements of Merensky pillar behaviour at Impala Platinum

    CSIR Research Space (South Africa)

    Watson, BP


    Full Text Available to stabilize the stoping excavations. This paper describes the in situ measurement, of stress within a Merensky pillar from Impala Platinum. These measurements were used to derive a stress-strain curve that includes pre and post failure behaviour. 2D FLAC...

  11. Electroreduction of cefetamet on mercury platinum and gold electrodes

    Directory of Open Access Journals (Sweden)

    P. ZUMAN


    Full Text Available The electroreduction of cefetamet (CEF using gold and platinum electrodes has been investigated in slightly alkaline medium (pH 8.40 where adsorption, previously observed at mercury electrode, was pronounced. This investigation was performed in order to determine whether the adsorption interfers with the reduction process even at solid electrodes and to compare with a mercury electrode.

  12. Platinum on Carbon Nanofibers as Catalyst for Cinnamaldehyde Hydrogenation

    NARCIS (Netherlands)

    Plomp, A.J.


    The aim of the work described in this thesis was to investigate the role and nature of nanostructured carbon materials, oxygen surface groups and promoters on platinum-based catalysts for the selective hydrogenation of cinnamaldehyde. The selective hydrogenation of cinnamaldehyde to cinnamyl alcohol

  13. Platinum redispersion on metal oxides in low temperature fuel cells

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir; Cerri, Isotta; Nagami, Tetsuo


    in detail; however, due to different operating conditions it is not straightforward to link the chemical and the electrochemical environment. The largest differences reflect in (1) the oxidation state of the surface (the oxygen species coverage), (2) temperature and (3) the possibility of platinum...

  14. Preparation of low-platinum-content platinum-nickel, platinum-cobalt binary alloy and platinum-nickel-cobalt ternary alloy catalysts for oxygen reduction reaction in polymer electrolyte fuel cells (United States)

    Li, Mu; Lei, Yanhua; Sheng, Nan; Ohtsuka, Toshiaki


    A series of low-platinum-content platinum-nickel (Pt-Ni), platinum-cobalt (Pt-Co) binary alloys and platinum-nickel-cobalt (Pt-Ni-Co) ternary alloys electrocatalysts were successfully prepared by a three-step process based on electrodeposition technique and studied as electrocatalysts for oxygen reduction reaction (ORR) in polymer-electrolyte fuel cells. Kinetics of ORR was studied in 0.5 M H2SO4 solution on the Pt-Ni, Pt-Co and Pt-Ni-Co alloys catalysts using rotating disk electrode technique. Both the series of Pt-Ni, Pt-Co binary alloys and the Pt-Ni-Co ternary alloys catalysts exhibited an obvious enhancement of ORR activity in comparison with pure Pt. The significant promotion of ORR activities of Pt-Ni and Pt-Co binary alloys was attributed to the enhancement of the first electron-transfer step, whereas, Pt-Ni-Co ternary alloys presented a more complicated mechanism during the electrocatalysis process but a much more efficient ORR activities than the binary alloys.

  15. Polyamide platinum anticancer complexes designed to target specific DNA sequences. (United States)

    Jaramillo, David; Wheate, Nial J; Ralph, Stephen F; Howard, Warren A; Tor, Yitzhak; Aldrich-Wright, Janice R


    Two new platinum complexes, trans-chlorodiammine[N-(2-aminoethyl)-4-[4-(N-methylimidazole-2-carboxamido)-N-methylpyrrole-2-carboxamido]-N-methylpyrrole-2-carboxamide]platinum(II) chloride (DJ1953-2) and trans-chlorodiammine[N-(6-aminohexyl)-4-[4-(N-methylimidazole-2-carboxamido)-N-methylpyrrole-2-carboxamido]-N-methylpyrrole-2-carboxamide]platinum(II) chloride (DJ1953-6) have been synthesized as proof-of-concept molecules in the design of agents that can specifically target genes in DNA. Coordinate covalent binding to DNA was demonstrated with electrospray ionization mass spectrometry. Using circular dichroism, these complexes were found to show greater DNA binding affinity to the target sequence: d(CATTGTCAGAC)(2), than toward either d(GTCTGTCAATG)(2,) which contains different flanking sequences, or d(CATTGAGAGAC)(2), which contains a double base pair mismatch sequence. DJ1953-2 unwinds the DNA helix by around 13 degrees , but neither metal complex significantly affects the DNA melting temperature. Unlike simple DNA minor groove binders, DJ1953-2 is able to inhibit, in vitro, RNA synthesis. The cytotoxicity of both metal complexes in the L1210 murine leukaemia cell line was also determined, with DJ1953-6 (34 microM) more active than DJ1953-2 (>50 microM). These results demonstrate the potential of polyamide platinum complexes and provide the structural basis for designer agents that are able to recognize biologically relevant sequences and prevent DNA transcription and replication.

  16. Molecular pathways: the immunogenic effects of platinum-based chemotherapeutics

    NARCIS (Netherlands)

    Hato, S.V.; Khong, A.; Vries, I.J.M. de; Lesterhuis, W.J.


    The platinum-based drugs cisplatin, carboplatin, and oxaliplatin belong to the most widely used chemotherapeutics in oncology, showing clinical efficacy against many solid tumors. Their main mechanism of action is believed to be the induction of cancer cell apoptosis as a response to their covalent

  17. Effect of heat leaks in platinum resistance thermometry. (United States)

    Goldratt, E; Yeshurun, Y; Greenfield, A J


    The effect of heat leaks in platinum resistance thermometry is analyzed. An experimental method is proposed for estimating the magnitude of this effect. Results are reported for the measurement of the temperature of a hot, solid body under different heat-leak configurations. Design criteria for thermometers are presented which minimize the effect of such heat leaks.

  18. Production of platinum radioisotopes at Brookhaven Linac Isotope Producer (BLIP

    Directory of Open Access Journals (Sweden)

    Smith Suzanne V.


    Full Text Available The accelerator production of platinum isotopes was investigated at the Brookhaven Linac Isotope Producer (BLIP. In this study high purity natural platinum foils were irradiated at 53.2, 65.7, 105.2, 151.9, 162.9 and 173.3.MeV. The irradiated foils were digested in aqua regia and then converted to their hydrochloride salt with concentrated hydrochloric acid before analyzing by gamma spectrometry periodically for at least 10 days post end of bombardment. A wide range of platinum (Pt, gold (Au and iridium (Ir isotopes were identified. Effective cross sections at BLIP for Pt-188, Pt-189, Pt-191 and Pt-195m were compared to literature and theoretical cross sections determined using Empire-3.2. The majority of the effective cross sections (<70 MeV confirm those reported in the literature. While the absolute values of the theoretical cross sections were up to a factor of 3 lower, Empire 3.2 modeled thresholds and maxima correlated well with experimental values. Preliminary evaluation into a rapid separation of Pt isotopes from high levels of Ir and Au isotopes proved to be a promising approach for large scale production. In conclusion, this study demonstrated that with the use of isotopically enriched target material accelerator production of selected platinum isotopes is feasible over a wide proton energy range.

  19. A Multimethod Approach for Investigating Algal Toxicity of Platinum Nanoparticles

    DEFF Research Database (Denmark)

    Sørensen, Sara Nørgaard; Engelbrekt, Christian; Lützhøft, Hans-Christian Holten


    The ecotoxicity of platinum nanoparticles (PtNPs) widely used in for example automotive catalytic converters, is largely unknown. This study employs various characterization techniques and toxicity end points to investigate PtNP toxicity toward the green microalgae Pseudokirchneriella subcapitata...

  20. Responses of fibroblasts and glial cells to nanostructured platinum surfaces (United States)

    Pennisi, C. P.; Sevcencu, C.; Dolatshahi-Pirouz, A.; Foss, M.; Lundsgaard Hansen, J.; Nylandsted Larsen, A.; Zachar, V.; Besenbacher, F.; Yoshida, K.


    The chronic performance of implantable neural prostheses is affected by the growth of encapsulation tissue onto the stimulation electrodes. Encapsulation is associated with activation of connective tissue cells at the electrode's metallic contacts, usually made of platinum. Since surface nanotopography can modulate the cellular responses to materials, the aim of the present work was to evaluate the 'in vitro' responses of connective tissue cells to platinum strictly by modulating its surface nanoroughness. Using molecular beam epitaxy combined with sputtering, we produced platinum nanostructured substrates consisting of irregularly distributed nanopyramids and investigated their effect on the proliferation, cytoskeletal organization and cellular morphology of primary fibroblasts and transformed glial cells. Cells were cultured on these substrates and their responses to surface roughness were studied. After one day in culture, the fibroblasts were more elongated and their cytoskeleton less mature when cultured on rough substrates. This effect increased as the roughness of the surface increased and was associated with reduced cell proliferation throughout the observation period (4 days). Morphological changes also occurred in glial cells, but they were triggered by a different roughness scale and did not affect cellular proliferation. In conclusion, surface nanotopography modulates the responses of fibroblasts and glial cells to platinum, which may be an important factor in optimizing the tissue response to implanted neural electrodes.