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G E Thompson - One of the best experts on this subject based on the ideXlab platform.

  • thermogravimetric differential thermal analysis of the solid state decomposition of Ammonium Tetrathiomolybdate during heating in argon
    Journal of Materials Science, 1998
    Co-Authors: H W Wang, P Skeldon, G E Thompson
    Abstract:

    The formation of MoS2 by thermal decomposition of Ammonium Tetrathiomolybdate (ATT) solids under an argon atmosphere has been studied by simultaneous thermogravimetric and differential thermal analysis. The sequential products for the decomposition upon heating to 700 °C is ATT (hydrated)→(NH4)2MoS4→(NH4)HMoS4→H2MoS4→MoS3→ Mo2S5→MoS2. MoS2 forms between 230 and 260 °C and remains stable up to about 360 °C when it tends to be oxidized by residual oxygen, if present in the atmosphere. These findings suggest that the synthesis of MoS2 from (NH4)2MoS4 via formation of MoS3 is not a direct process, as previously reported, but rather a complex process involving a number of intermediate products (NH4)HMoS4, H2MoS4 and Mo2S5 which have not been reported before. That these products are only specific to the very narrow temperature regimes as revealed suggests that they are very unstable and short lived, that their presence is transient in nature and thus that ex-situ characterization of them is normally difficult. The presence of these intermediate products, as justified experimentally, is further interpreted in terms of their mutual structural similarities which improve understanding as to why MoS2 can usually be prepared from ATT by thermal decomposition, as in this case, or by other techniques, such as anodizing. Laminar morphology of MoS2 is revealed by transmission electron microscopy and its crystal structure examined by selected-area diffraction. Further ex-situ examination by X-ray photoelectron spectroscopy of this end product supports the feasibility of preparing MoS2 from aqueous solutions by anodizing. © 1998 Kluwer Academic Publishers

  • Thermogravimetric–differential thermal analysis of the solid-state decomposition of Ammonium Tetrathiomolybdate during heating in argon
    Journal of Materials Science, 1998
    Co-Authors: H W Wang, P Skeldon, G E Thompson
    Abstract:

    The formation of MoS2 by thermal decomposition of Ammonium Tetrathiomolybdate (ATT) solids under an argon atmosphere has been studied by simultaneous thermogravimetric and differential thermal analysis. The sequential products for the decomposition upon heating to 700 °C is ATT (hydrated)→(NH4)2MoS4→(NH4)HMoS4→H2MoS4→MoS3→ Mo2S5→MoS2. MoS2 forms between 230 and 260 °C and remains stable up to about 360 °C when it tends to be oxidized by residual oxygen, if present in the atmosphere. These findings suggest that the synthesis of MoS2 from (NH4)2MoS4 via formation of MoS3 is not a direct process, as previously reported, but rather a complex process involving a number of intermediate products (NH4)HMoS4, H2MoS4 and Mo2S5 which have not been reported before. That these products are only specific to the very narrow temperature regimes as revealed suggests that they are very unstable and short lived, that their presence is transient in nature and thus that ex-situ characterization of them is normally difficult. The presence of these intermediate products, as justified experimentally, is further interpreted in terms of their mutual structural similarities which improve understanding as to why MoS2 can usually be prepared from ATT by thermal decomposition, as in this case, or by other techniques, such as anodizing. Laminar morphology of MoS2 is revealed by transmission electron microscopy and its crystal structure examined by selected-area diffraction. Further ex-situ examination by X-ray photoelectron spectroscopy of this end product supports the feasibility of preparing MoS2 from aqueous solutions by anodizing. © 1998 Kluwer Academic Publishers

  • xps studies of mos2 formation from Ammonium Tetrathiomolybdate solutions
    Surface & Coatings Technology, 1997
    Co-Authors: H W Wang, P Skeldon, G E Thompson
    Abstract:

    Abstract Preparation of MoS 2 by acidification of Ammonium Tetrathiomolybdate solution has been studied by X-ray photoelectron spectroscopy (XPS). The precipitates formed from the solution are mainly composed of MoS 3 , the Mo 3d chemical shift of which is approximately 4.2eV. Heat treatments of the above product at 450 and 850°C, in a vacuum of 1.33 × 10 −4 Pa, lead largely to formation of MoS 2 , with typical chemical shifts of abouth 1.2eV. The MoS 2 formed consists of nano-sized, crystalline particles of hexagonal (2H-type) structure. The validity of MoS 2 formation by this route is confirmed by comparative study, namely the decomposition of ATT solids under the same respective heat treatment conditions. Apart from these main aspects, origins of minor XPS peaks are also considered.

  • synthesis and characterization of molybdenum disulphide formed from Ammonium Tetrathiomolybdate
    Journal of Materials Science, 1997
    Co-Authors: H W Wang, P Skeldon, G E Thompson, G C Wood
    Abstract:

    An investigation has been carried out into the possibility of in situ formation of MoS2 within porous anodic films on aluminium, to improve subsequent tribological behaviour, by re-anodizing in thiomolybdate electrolyte. Acidification of thiomolybdate was employed to simulate the conditions for formation of the sulphide at the anodic film/electrolyte interface, followed by appropriate vacuum heat treatments to study possible temperature effects on the sulphide due to either friction or Joule heating during anodizing. The products of both acidification and heat treatment, characterized by X-ray powder diffraction and scanning electron microscopy, were compared with those formed by direct thermal decomposition of Ammonium Tetrathiomolybdate crystals. The precipitate formed by acidification was mainly amorphous molybdenum trisulphide (MoS3), which on heat treatment at 450 and 850°C yielded 3R-MoS2. 3R-MoS2 also formed by the thermal decomposition of thiomolybdate crystals. Thermogravimetric and differential thermal analyses showed that the decomposition of MoS3 to MoS2 occurred in the range 220–370°C and revealed the sequence of reaction steps. The findings suggest that mainly amorphous MoS3 is formed as a consequence of changes in the pH of the film/electrolyte interface during re-anodizing but the product is relatively easily transformed to crystalline MoS2 on moderate heating which may occur during wear processes.

  • Development and tribological assessment of self-lubricating anodic films on aluminium
    Surface and Coatings Technology, 1997
    Co-Authors: H W Wang, Peter Skeldon, G E Thompson
    Abstract:

    Abstract The self-lubricating, porous anodic films formed on aluminium by a re-anodizing treatment in Ammonium Tetrathiomolybdate electrolyte is examined by transmission electron microscopy and X-ray photoelectron spectroscopy. Precipitation of mainly amorphous MoS 3 , or a mixture of MoS 2 and S, is revealed, which leads to a significantly reduced coefficient of friction.

H W Wang - One of the best experts on this subject based on the ideXlab platform.

  • thermogravimetric differential thermal analysis of the solid state decomposition of Ammonium Tetrathiomolybdate during heating in argon
    Journal of Materials Science, 1998
    Co-Authors: H W Wang, P Skeldon, G E Thompson
    Abstract:

    The formation of MoS2 by thermal decomposition of Ammonium Tetrathiomolybdate (ATT) solids under an argon atmosphere has been studied by simultaneous thermogravimetric and differential thermal analysis. The sequential products for the decomposition upon heating to 700 °C is ATT (hydrated)→(NH4)2MoS4→(NH4)HMoS4→H2MoS4→MoS3→ Mo2S5→MoS2. MoS2 forms between 230 and 260 °C and remains stable up to about 360 °C when it tends to be oxidized by residual oxygen, if present in the atmosphere. These findings suggest that the synthesis of MoS2 from (NH4)2MoS4 via formation of MoS3 is not a direct process, as previously reported, but rather a complex process involving a number of intermediate products (NH4)HMoS4, H2MoS4 and Mo2S5 which have not been reported before. That these products are only specific to the very narrow temperature regimes as revealed suggests that they are very unstable and short lived, that their presence is transient in nature and thus that ex-situ characterization of them is normally difficult. The presence of these intermediate products, as justified experimentally, is further interpreted in terms of their mutual structural similarities which improve understanding as to why MoS2 can usually be prepared from ATT by thermal decomposition, as in this case, or by other techniques, such as anodizing. Laminar morphology of MoS2 is revealed by transmission electron microscopy and its crystal structure examined by selected-area diffraction. Further ex-situ examination by X-ray photoelectron spectroscopy of this end product supports the feasibility of preparing MoS2 from aqueous solutions by anodizing. © 1998 Kluwer Academic Publishers

  • Thermogravimetric–differential thermal analysis of the solid-state decomposition of Ammonium Tetrathiomolybdate during heating in argon
    Journal of Materials Science, 1998
    Co-Authors: H W Wang, P Skeldon, G E Thompson
    Abstract:

    The formation of MoS2 by thermal decomposition of Ammonium Tetrathiomolybdate (ATT) solids under an argon atmosphere has been studied by simultaneous thermogravimetric and differential thermal analysis. The sequential products for the decomposition upon heating to 700 °C is ATT (hydrated)→(NH4)2MoS4→(NH4)HMoS4→H2MoS4→MoS3→ Mo2S5→MoS2. MoS2 forms between 230 and 260 °C and remains stable up to about 360 °C when it tends to be oxidized by residual oxygen, if present in the atmosphere. These findings suggest that the synthesis of MoS2 from (NH4)2MoS4 via formation of MoS3 is not a direct process, as previously reported, but rather a complex process involving a number of intermediate products (NH4)HMoS4, H2MoS4 and Mo2S5 which have not been reported before. That these products are only specific to the very narrow temperature regimes as revealed suggests that they are very unstable and short lived, that their presence is transient in nature and thus that ex-situ characterization of them is normally difficult. The presence of these intermediate products, as justified experimentally, is further interpreted in terms of their mutual structural similarities which improve understanding as to why MoS2 can usually be prepared from ATT by thermal decomposition, as in this case, or by other techniques, such as anodizing. Laminar morphology of MoS2 is revealed by transmission electron microscopy and its crystal structure examined by selected-area diffraction. Further ex-situ examination by X-ray photoelectron spectroscopy of this end product supports the feasibility of preparing MoS2 from aqueous solutions by anodizing. © 1998 Kluwer Academic Publishers

  • xps studies of mos2 formation from Ammonium Tetrathiomolybdate solutions
    Surface & Coatings Technology, 1997
    Co-Authors: H W Wang, P Skeldon, G E Thompson
    Abstract:

    Abstract Preparation of MoS 2 by acidification of Ammonium Tetrathiomolybdate solution has been studied by X-ray photoelectron spectroscopy (XPS). The precipitates formed from the solution are mainly composed of MoS 3 , the Mo 3d chemical shift of which is approximately 4.2eV. Heat treatments of the above product at 450 and 850°C, in a vacuum of 1.33 × 10 −4 Pa, lead largely to formation of MoS 2 , with typical chemical shifts of abouth 1.2eV. The MoS 2 formed consists of nano-sized, crystalline particles of hexagonal (2H-type) structure. The validity of MoS 2 formation by this route is confirmed by comparative study, namely the decomposition of ATT solids under the same respective heat treatment conditions. Apart from these main aspects, origins of minor XPS peaks are also considered.

  • synthesis and characterization of molybdenum disulphide formed from Ammonium Tetrathiomolybdate
    Journal of Materials Science, 1997
    Co-Authors: H W Wang, P Skeldon, G E Thompson, G C Wood
    Abstract:

    An investigation has been carried out into the possibility of in situ formation of MoS2 within porous anodic films on aluminium, to improve subsequent tribological behaviour, by re-anodizing in thiomolybdate electrolyte. Acidification of thiomolybdate was employed to simulate the conditions for formation of the sulphide at the anodic film/electrolyte interface, followed by appropriate vacuum heat treatments to study possible temperature effects on the sulphide due to either friction or Joule heating during anodizing. The products of both acidification and heat treatment, characterized by X-ray powder diffraction and scanning electron microscopy, were compared with those formed by direct thermal decomposition of Ammonium Tetrathiomolybdate crystals. The precipitate formed by acidification was mainly amorphous molybdenum trisulphide (MoS3), which on heat treatment at 450 and 850°C yielded 3R-MoS2. 3R-MoS2 also formed by the thermal decomposition of thiomolybdate crystals. Thermogravimetric and differential thermal analyses showed that the decomposition of MoS3 to MoS2 occurred in the range 220–370°C and revealed the sequence of reaction steps. The findings suggest that mainly amorphous MoS3 is formed as a consequence of changes in the pH of the film/electrolyte interface during re-anodizing but the product is relatively easily transformed to crystalline MoS2 on moderate heating which may occur during wear processes.

  • Development and tribological assessment of self-lubricating anodic films on aluminium
    Surface and Coatings Technology, 1997
    Co-Authors: H W Wang, Peter Skeldon, G E Thompson
    Abstract:

    Abstract The self-lubricating, porous anodic films formed on aluminium by a re-anodizing treatment in Ammonium Tetrathiomolybdate electrolyte is examined by transmission electron microscopy and X-ray photoelectron spectroscopy. Precipitation of mainly amorphous MoS 3 , or a mixture of MoS 2 and S, is revealed, which leads to a significantly reduced coefficient of friction.

George J Brewer - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of Tetrathiomolybdate in the R6/2 model of Huntington disease.
    Neuroscience letters, 2009
    Co-Authors: Sara J. Tallaksen-greene, George J Brewer, Anita Janiszewska, Kasha Benton, Guoqing Hou, Robert P. Dick, Roger L. Albin
    Abstract:

    Huntington disease is an uncommon autosomal dominant neurodegenerative disorder caused by expanded polyglutamine repeats in the huntingtin protein. The proximate mechanisms responsible for neurodegeneration are unknown. Copper ions may play a role in Huntington disease by promoting oligomerization of expanded polyglutamine repeat protein fragments. Ammonium Tetrathiomolybdate is a copper complexing agent with demonstrated tolerability and efficacy in another neurodegenerative disorder, Wilson disease. We evaluated Ammonium Tetrathiomolybdate in the R6/2 transgenic mouse model of Huntington disease. Ammonium Tetrathiomolybdate treatment delayed the onset of motor dysfunction in R6/2 mice. There was a trend towards reduced striatal degeneration, suggesting a neuroprotective effect of Ammonium Tetrathiomolybdate in this model. Given its known tolerability in humans with neurodegeneration, Ammonium Tetrathiomolybdate could be considered as a candidate for clinical trials in Huntington disease.

  • Treatment of Wilson disease with Ammonium Tetrathiomolybdate: III. Initial therapy in a total of 55 neurologically affected patients and follow-up with zinc therapy.
    Archives of neurology, 2003
    Co-Authors: George J Brewer, Julia Sitterly, Robert B Dick, Peter Hedera, Karen J Kluin, Martha Carlson, Fred Askari, John K. Fink
    Abstract:

    It is unclear what anticopper drug to use for patients with Wilson disease who present with neurologic manifestations because penicillamine often makes them neurologically worse and zinc is slow acting. To evaluate the frequency of neurologic worsening and drug adverse effects with Ammonium Tetrathiomolybdate. Open-label study of 55 untreated patients (22 of them new) presenting with neurologic Wilson disease treated with Tetrathiomolybdate varying from 120 to 410 mg/d for 8 weeks and then followed up for 3 years. Neurologic function was assessed with scored neurologic and speech tests. A university hospital referral setting. All untreated, newly diagnosed patients with neurologic Wilson disease. Treatment with Tetrathiomolybdate. Neurologic function was evaluated by neurologic and speech examinations. Drug adverse effects were evaluated by complete blood cell counts and biochemical measures. Only 2 (4%) of 55 patients treated with Tetrathiomolybdate showed neurologic deterioration, compared with an estimated 50% of penicillamine-treated patients. Five of the 22 new patients exhibited bone marrow suppression and 3 had aminotransferase elevations. These numbers are higher than in the original 33 patients and appear to be due primarily to a more rapid dose escalation. Tetrathiomolybdate shows excellent efficacy in patients with Wilson disease who present with neurologic manifestations. With rapid escalation of dose, adverse effects from bone marrow suppression or aminotransferase elevations can occur.

  • treatment of wilson disease with Ammonium Tetrathiomolybdate iii initial therapy in a total of 55 neurologically affected patients and follow up with zinc therapy
    JAMA Neurology, 1996
    Co-Authors: George J Brewer, Frederick K Askari, Julia Sitterly, Martha D Carlson, Robert B Dick, Peter Hedera, Karen J Kluin, John K. Fink
    Abstract:

    Objective: To test the efficacy and toxic effects of Ammonium Tetrathiomolybdate in the initial treatment of a relatively large series of patients with neurologic symptoms and signs caused by Wilson disease. Two key aspects of efficacy are to preserve the neurologic function present at the onset of therapy and to maximize the opportunity for long-term recovery. Design: An open study of 33 patients treated for 8 weeks each, including further follow-up data on the original 17 patients. Neurologic function was evaluated by frequent quantitative neurologic and speech pathology examinations. Several copper-related variables were studied to evaluate the effect of the drug on copper, and several biochemical and clinical variables were studied to evaluate potential toxic effects. Patients were then followed up at yearly intervals, with follow-up periods of 1 to 8 years reported. Setting: A university hospital referral setting. Intervention: Patients were generally treated for 8 weeks with Tetrathiomolybdate, followed by zinc maintenance therapy. Main Outcome Measures: Neurologic function was evaluated by quantitative neurologic and motor speech examinations and magnetic resonance imaging scans of the brain. Results: During the 8 weeks of Tetrathiomolybdate administration, only 1 of the 33 patients showed deterioration in neurologic function. Copper status and potential further toxic effects were generally well controlled quickly. Evaluation of data from individual patients revealed evidence of a toxic side effect in only 1 patient, who exhibited reversible anemia. During the ensuing period of follow-up of 1 to 6 years, neurologic recovery in most patients was good to excellent. Conclusions: Tetrathiomolybdate appears to be an excellent form of initial treatment in patients with Wilson disease who present with neurologic symptoms and signs. In contrast to penicillamine therapy, initial treatment with Tetrathiomolybdate rarely allows further, often irreversible, neurologic deterioration.

  • Treatment of Wilson disease with Ammonium Tetrathiomolybdate. II. Initial therapy in 33 neurologically affected patients and follow-up with zinc therapy.
    Archives of neurology, 1996
    Co-Authors: George J Brewer, Karen J Kluin, John K. Fink, Robert D Dick, Virginia Johnson, J A Brunberg
    Abstract:

    To test the efficacy and toxic effects of Ammonium Tetrathiomolybdate in the initial treatment of a relatively large series of patients with neurologic symptoms and signs caused by Wilson disease. Two key aspects of efficacy are to preserve the neurologic function present at the onset of therapy and to maximize the opportunity for long-term recovery. An open study of 33 patients treated for 8 weeks each, including further follow-up data on the original 17 patients. Neurologic function was evaluated by frequent quantitative neurologic and speech pathology examinations. Several copper-related variables were studied to evaluate the effect of the drug on copper, and several biochemical and clinical variables were studied to evaluate potential toxic effects. Patients were then followed up at yearly intervals, with follow-up periods of 1 to 8 years reported. A university hospital referral setting. Patients were generally treated for 8 weeks with Tetrathiomolybdate, followed by zinc maintenance therapy. Neurologic function was evaluated by quantitative neurologic and motor speech examinations and magnetic resonance imaging scans of the brain. During the 8 weeks of Tetrathiomolybdate administration, only 1 of the 33 patients showed deterioration in neurologic function. Copper status and potential further toxic effects were generally well controlled quickly. Evaluation of data from individual patients revealed evidence of a toxic side effect in only 1 patient, who exhibited reversible anemia. During the ensuing period of follow-up of 1 to 6 years, neurologic recovery in most patients was good to excellent. Tetrathiomolybdate appears to be an excellent form of initial treatment in patients with Wilson disease who present with neurologic symptoms and signs. In contrast to penicillamine therapy, initial treatment with Tetrathiomolybdate rarely allows further, often irreversible, neurologic deterioration.

  • treatment of wilson s disease with Ammonium Tetrathiomolybdate i initial therapy in 17 neurologically affected patients
    JAMA Neurology, 1994
    Co-Authors: George J Brewer, Karen J Kluin, John K. Fink, Robert D Dick, Virginia Johnson, Yuxun Wang, Vilma Yuzbasiyangurkan, Alex M Aisen
    Abstract:

    Objective: To test the efficacy and toxicity of a new drug, Ammonium Tetrathiomolybdate, in the initial treatment of a relatively large series of patients presenting with neurologic signs and symptoms caused by Wilson's disease. The key aspect of efficacy was to preserve the neurologic function present at the onset of therapy. Design: An open study of 17 patients treated for 8 weeks each. Neurologic function was evaluated by frequent quantitative neurologic and speech examinations. Several copper-related variables were studied to evaluate the effect of the drug on copper, and a large number of biochemical and clinical variables were studied to evaluate potential toxicity. Patients were then followed up at yearly intervals, with follow-up periods of 1 to 5 years reported. Setting: A university hospital referral setting. Intervention: Patients were generally treated for 8 weeks with Tetrathiomolybdate, followed by zinc maintenance therapy. Main Outcome Measures: Neurologic function was evaluated by quantitative neurologic and speech examinations. Results: None of the patients suffered a loss of neurologic function. Copper status and potential further toxic effects were generally well controlled quickly. No toxic effects resulted from administration of Tetrathiomolybdate. During the ensuing period of follow-up of 1 to 5 years, neurologic recovery in most patients was good to excellent. Conclusions: Tetrathiomolybdate appears to be an excellent form of initial treatment in patients with Wilson's disease presenting with neurologic signs and symptoms. In contrast to penicillamine therapy, initial treatment with Tetrathiomolybdate does not result in further, often irreversible neurologic deterioration.

John K. Fink - One of the best experts on this subject based on the ideXlab platform.

  • Treatment of Wilson disease with Ammonium Tetrathiomolybdate: III. Initial therapy in a total of 55 neurologically affected patients and follow-up with zinc therapy.
    Archives of neurology, 2003
    Co-Authors: George J Brewer, Julia Sitterly, Robert B Dick, Peter Hedera, Karen J Kluin, Martha Carlson, Fred Askari, John K. Fink
    Abstract:

    It is unclear what anticopper drug to use for patients with Wilson disease who present with neurologic manifestations because penicillamine often makes them neurologically worse and zinc is slow acting. To evaluate the frequency of neurologic worsening and drug adverse effects with Ammonium Tetrathiomolybdate. Open-label study of 55 untreated patients (22 of them new) presenting with neurologic Wilson disease treated with Tetrathiomolybdate varying from 120 to 410 mg/d for 8 weeks and then followed up for 3 years. Neurologic function was assessed with scored neurologic and speech tests. A university hospital referral setting. All untreated, newly diagnosed patients with neurologic Wilson disease. Treatment with Tetrathiomolybdate. Neurologic function was evaluated by neurologic and speech examinations. Drug adverse effects were evaluated by complete blood cell counts and biochemical measures. Only 2 (4%) of 55 patients treated with Tetrathiomolybdate showed neurologic deterioration, compared with an estimated 50% of penicillamine-treated patients. Five of the 22 new patients exhibited bone marrow suppression and 3 had aminotransferase elevations. These numbers are higher than in the original 33 patients and appear to be due primarily to a more rapid dose escalation. Tetrathiomolybdate shows excellent efficacy in patients with Wilson disease who present with neurologic manifestations. With rapid escalation of dose, adverse effects from bone marrow suppression or aminotransferase elevations can occur.

  • treatment of wilson disease with Ammonium Tetrathiomolybdate iii initial therapy in a total of 55 neurologically affected patients and follow up with zinc therapy
    JAMA Neurology, 1996
    Co-Authors: George J Brewer, Frederick K Askari, Julia Sitterly, Martha D Carlson, Robert B Dick, Peter Hedera, Karen J Kluin, John K. Fink
    Abstract:

    Objective: To test the efficacy and toxic effects of Ammonium Tetrathiomolybdate in the initial treatment of a relatively large series of patients with neurologic symptoms and signs caused by Wilson disease. Two key aspects of efficacy are to preserve the neurologic function present at the onset of therapy and to maximize the opportunity for long-term recovery. Design: An open study of 33 patients treated for 8 weeks each, including further follow-up data on the original 17 patients. Neurologic function was evaluated by frequent quantitative neurologic and speech pathology examinations. Several copper-related variables were studied to evaluate the effect of the drug on copper, and several biochemical and clinical variables were studied to evaluate potential toxic effects. Patients were then followed up at yearly intervals, with follow-up periods of 1 to 8 years reported. Setting: A university hospital referral setting. Intervention: Patients were generally treated for 8 weeks with Tetrathiomolybdate, followed by zinc maintenance therapy. Main Outcome Measures: Neurologic function was evaluated by quantitative neurologic and motor speech examinations and magnetic resonance imaging scans of the brain. Results: During the 8 weeks of Tetrathiomolybdate administration, only 1 of the 33 patients showed deterioration in neurologic function. Copper status and potential further toxic effects were generally well controlled quickly. Evaluation of data from individual patients revealed evidence of a toxic side effect in only 1 patient, who exhibited reversible anemia. During the ensuing period of follow-up of 1 to 6 years, neurologic recovery in most patients was good to excellent. Conclusions: Tetrathiomolybdate appears to be an excellent form of initial treatment in patients with Wilson disease who present with neurologic symptoms and signs. In contrast to penicillamine therapy, initial treatment with Tetrathiomolybdate rarely allows further, often irreversible, neurologic deterioration.

  • Treatment of Wilson disease with Ammonium Tetrathiomolybdate. II. Initial therapy in 33 neurologically affected patients and follow-up with zinc therapy.
    Archives of neurology, 1996
    Co-Authors: George J Brewer, Karen J Kluin, John K. Fink, Robert D Dick, Virginia Johnson, J A Brunberg
    Abstract:

    To test the efficacy and toxic effects of Ammonium Tetrathiomolybdate in the initial treatment of a relatively large series of patients with neurologic symptoms and signs caused by Wilson disease. Two key aspects of efficacy are to preserve the neurologic function present at the onset of therapy and to maximize the opportunity for long-term recovery. An open study of 33 patients treated for 8 weeks each, including further follow-up data on the original 17 patients. Neurologic function was evaluated by frequent quantitative neurologic and speech pathology examinations. Several copper-related variables were studied to evaluate the effect of the drug on copper, and several biochemical and clinical variables were studied to evaluate potential toxic effects. Patients were then followed up at yearly intervals, with follow-up periods of 1 to 8 years reported. A university hospital referral setting. Patients were generally treated for 8 weeks with Tetrathiomolybdate, followed by zinc maintenance therapy. Neurologic function was evaluated by quantitative neurologic and motor speech examinations and magnetic resonance imaging scans of the brain. During the 8 weeks of Tetrathiomolybdate administration, only 1 of the 33 patients showed deterioration in neurologic function. Copper status and potential further toxic effects were generally well controlled quickly. Evaluation of data from individual patients revealed evidence of a toxic side effect in only 1 patient, who exhibited reversible anemia. During the ensuing period of follow-up of 1 to 6 years, neurologic recovery in most patients was good to excellent. Tetrathiomolybdate appears to be an excellent form of initial treatment in patients with Wilson disease who present with neurologic symptoms and signs. In contrast to penicillamine therapy, initial treatment with Tetrathiomolybdate rarely allows further, often irreversible, neurologic deterioration.

  • treatment of wilson s disease with Ammonium Tetrathiomolybdate i initial therapy in 17 neurologically affected patients
    JAMA Neurology, 1994
    Co-Authors: George J Brewer, Karen J Kluin, John K. Fink, Robert D Dick, Virginia Johnson, Yuxun Wang, Vilma Yuzbasiyangurkan, Alex M Aisen
    Abstract:

    Objective: To test the efficacy and toxicity of a new drug, Ammonium Tetrathiomolybdate, in the initial treatment of a relatively large series of patients presenting with neurologic signs and symptoms caused by Wilson's disease. The key aspect of efficacy was to preserve the neurologic function present at the onset of therapy. Design: An open study of 17 patients treated for 8 weeks each. Neurologic function was evaluated by frequent quantitative neurologic and speech examinations. Several copper-related variables were studied to evaluate the effect of the drug on copper, and a large number of biochemical and clinical variables were studied to evaluate potential toxicity. Patients were then followed up at yearly intervals, with follow-up periods of 1 to 5 years reported. Setting: A university hospital referral setting. Intervention: Patients were generally treated for 8 weeks with Tetrathiomolybdate, followed by zinc maintenance therapy. Main Outcome Measures: Neurologic function was evaluated by quantitative neurologic and speech examinations. Results: None of the patients suffered a loss of neurologic function. Copper status and potential further toxic effects were generally well controlled quickly. No toxic effects resulted from administration of Tetrathiomolybdate. During the ensuing period of follow-up of 1 to 5 years, neurologic recovery in most patients was good to excellent. Conclusions: Tetrathiomolybdate appears to be an excellent form of initial treatment in patients with Wilson's disease presenting with neurologic signs and symptoms. In contrast to penicillamine therapy, initial treatment with Tetrathiomolybdate does not result in further, often irreversible neurologic deterioration.

P Skeldon - One of the best experts on this subject based on the ideXlab platform.

  • thermogravimetric differential thermal analysis of the solid state decomposition of Ammonium Tetrathiomolybdate during heating in argon
    Journal of Materials Science, 1998
    Co-Authors: H W Wang, P Skeldon, G E Thompson
    Abstract:

    The formation of MoS2 by thermal decomposition of Ammonium Tetrathiomolybdate (ATT) solids under an argon atmosphere has been studied by simultaneous thermogravimetric and differential thermal analysis. The sequential products for the decomposition upon heating to 700 °C is ATT (hydrated)→(NH4)2MoS4→(NH4)HMoS4→H2MoS4→MoS3→ Mo2S5→MoS2. MoS2 forms between 230 and 260 °C and remains stable up to about 360 °C when it tends to be oxidized by residual oxygen, if present in the atmosphere. These findings suggest that the synthesis of MoS2 from (NH4)2MoS4 via formation of MoS3 is not a direct process, as previously reported, but rather a complex process involving a number of intermediate products (NH4)HMoS4, H2MoS4 and Mo2S5 which have not been reported before. That these products are only specific to the very narrow temperature regimes as revealed suggests that they are very unstable and short lived, that their presence is transient in nature and thus that ex-situ characterization of them is normally difficult. The presence of these intermediate products, as justified experimentally, is further interpreted in terms of their mutual structural similarities which improve understanding as to why MoS2 can usually be prepared from ATT by thermal decomposition, as in this case, or by other techniques, such as anodizing. Laminar morphology of MoS2 is revealed by transmission electron microscopy and its crystal structure examined by selected-area diffraction. Further ex-situ examination by X-ray photoelectron spectroscopy of this end product supports the feasibility of preparing MoS2 from aqueous solutions by anodizing. © 1998 Kluwer Academic Publishers

  • Thermogravimetric–differential thermal analysis of the solid-state decomposition of Ammonium Tetrathiomolybdate during heating in argon
    Journal of Materials Science, 1998
    Co-Authors: H W Wang, P Skeldon, G E Thompson
    Abstract:

    The formation of MoS2 by thermal decomposition of Ammonium Tetrathiomolybdate (ATT) solids under an argon atmosphere has been studied by simultaneous thermogravimetric and differential thermal analysis. The sequential products for the decomposition upon heating to 700 °C is ATT (hydrated)→(NH4)2MoS4→(NH4)HMoS4→H2MoS4→MoS3→ Mo2S5→MoS2. MoS2 forms between 230 and 260 °C and remains stable up to about 360 °C when it tends to be oxidized by residual oxygen, if present in the atmosphere. These findings suggest that the synthesis of MoS2 from (NH4)2MoS4 via formation of MoS3 is not a direct process, as previously reported, but rather a complex process involving a number of intermediate products (NH4)HMoS4, H2MoS4 and Mo2S5 which have not been reported before. That these products are only specific to the very narrow temperature regimes as revealed suggests that they are very unstable and short lived, that their presence is transient in nature and thus that ex-situ characterization of them is normally difficult. The presence of these intermediate products, as justified experimentally, is further interpreted in terms of their mutual structural similarities which improve understanding as to why MoS2 can usually be prepared from ATT by thermal decomposition, as in this case, or by other techniques, such as anodizing. Laminar morphology of MoS2 is revealed by transmission electron microscopy and its crystal structure examined by selected-area diffraction. Further ex-situ examination by X-ray photoelectron spectroscopy of this end product supports the feasibility of preparing MoS2 from aqueous solutions by anodizing. © 1998 Kluwer Academic Publishers

  • xps studies of mos2 formation from Ammonium Tetrathiomolybdate solutions
    Surface & Coatings Technology, 1997
    Co-Authors: H W Wang, P Skeldon, G E Thompson
    Abstract:

    Abstract Preparation of MoS 2 by acidification of Ammonium Tetrathiomolybdate solution has been studied by X-ray photoelectron spectroscopy (XPS). The precipitates formed from the solution are mainly composed of MoS 3 , the Mo 3d chemical shift of which is approximately 4.2eV. Heat treatments of the above product at 450 and 850°C, in a vacuum of 1.33 × 10 −4 Pa, lead largely to formation of MoS 2 , with typical chemical shifts of abouth 1.2eV. The MoS 2 formed consists of nano-sized, crystalline particles of hexagonal (2H-type) structure. The validity of MoS 2 formation by this route is confirmed by comparative study, namely the decomposition of ATT solids under the same respective heat treatment conditions. Apart from these main aspects, origins of minor XPS peaks are also considered.

  • synthesis and characterization of molybdenum disulphide formed from Ammonium Tetrathiomolybdate
    Journal of Materials Science, 1997
    Co-Authors: H W Wang, P Skeldon, G E Thompson, G C Wood
    Abstract:

    An investigation has been carried out into the possibility of in situ formation of MoS2 within porous anodic films on aluminium, to improve subsequent tribological behaviour, by re-anodizing in thiomolybdate electrolyte. Acidification of thiomolybdate was employed to simulate the conditions for formation of the sulphide at the anodic film/electrolyte interface, followed by appropriate vacuum heat treatments to study possible temperature effects on the sulphide due to either friction or Joule heating during anodizing. The products of both acidification and heat treatment, characterized by X-ray powder diffraction and scanning electron microscopy, were compared with those formed by direct thermal decomposition of Ammonium Tetrathiomolybdate crystals. The precipitate formed by acidification was mainly amorphous molybdenum trisulphide (MoS3), which on heat treatment at 450 and 850°C yielded 3R-MoS2. 3R-MoS2 also formed by the thermal decomposition of thiomolybdate crystals. Thermogravimetric and differential thermal analyses showed that the decomposition of MoS3 to MoS2 occurred in the range 220–370°C and revealed the sequence of reaction steps. The findings suggest that mainly amorphous MoS3 is formed as a consequence of changes in the pH of the film/electrolyte interface during re-anodizing but the product is relatively easily transformed to crystalline MoS2 on moderate heating which may occur during wear processes.

  • synthesis of molybdenum disulphide by acidification of Ammonium Tetrathiomolybdate solutions
    Journal of Materials Science Letters, 1996
    Co-Authors: H W Wang, P Skeldon, G E Thompson, G C Wood
    Abstract:

    Generally categorized in a large family of transition metal dichalcogenide layer crystals, molybdenum disulfide (MoS2) has been the subject of significant research interest for applications in non-aqueous lithium batteries [1], catalytic hydrodesulphurization of petroleum [2], and antiwear achievement by reduction in friction [3-5]. The successful application of this semiconductor compound originates largely from the sandwich interlayer structure, loosely bound by Van der Waals forces, evidenced by easy cleavage in the [0 0 1] direction along which the (S-Me-S) layers are stacked to form the crystal [6]. Apart from its natural state, known as molybdenite, crystalline MoS2 can also be synthesized by hightemperature solid state reaction between stoichiometrically mixed molybdenum and sulphur powders in vacuum [7-9], thermal decomposition of Ammonium Tetrathiomolybdate ((NH4)2MoS4) [10, 11] or amorphous molybdenum trisulfide (MoS3) [9, 12], and by thermally assisted transformation of amorphous MoS2 powders [13]. Synthetic MoS2 can also be prepared by sputtering [14], electrodeposition [15] and chemical deposition techniques [16]. The present letter reports formation of MoS2, by appropriate thermal treatment of precipitates resulting from acidification of Ammonium Tetrathiomolybdate solution. As mentioned previously, although MoS2 can be prepared from Tetrathiomolybdate by thermal decomposition, the current work is of practical interest in that it produces evidence for in situ formation of MoS2 during anodizing of aluminium and its alloys in thiomolybdate electrolyte. Compared with the extensive research on the formation of alumina by anodizing, the formation of MoS2 during anodization has been rarely reported. Skeldon and Thompson [17] recently proposed to overcome the general poor surface retention of MoS2 by incorporating it, by anodizing, into a pre-anodized, hard porous alumina film on aluminium for tribological applications. The main anodic reaction during anodizing of aluminium results in proton generation at the pore base/electrolyte interface as follows