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A database of mapped global fishing activity 1950-2017. Sci Data 2024; 11:48. [PMID: 38191576 PMCID: PMC10774419 DOI: 10.1038/s41597-023-02824-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 12/06/2023] [Indexed: 01/10/2024] Open
Abstract
A new database on historical country-level fishing fleet capacity and effort is described, derived from a range of publicly available sources that were harmonized, converted to fishing effort, and mapped to 30-min spatial cells. The resulting data is comparable with widely used but more temporally-limited satellite-sourced Automatic Identification System (AIS) datasets for large vessels, while also documenting important smaller fleets and artisanal segments. It ranges from 1950 to 2017, and includes information on number of vessels, engine power, gross tonnage, and nominal effort, categorized by vessel length, gear type and targeted functional groups. The data can be aggregated to Large Marine Ecosystem, region and/or fishing country scales and provides a temporally and spatially explicit source for fishing effort and fleet capacity for studies aimed at understanding the implications of long-term changes in fishing activity in the global ocean.
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Food security challenged by declining efficiencies of artisanal fishing fleets: A global country-level analysis. GLOBAL FOOD SECURITY 2022. [DOI: 10.1016/j.gfs.2021.100598] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
UNLABELLED Ocean governance is complex and influenced by multiple drivers and actors with different worldviews and goals. While governance encompasses many elements, in this paper we focus on the processes that operate within and between states, civil society and local communities, and the market, including industry. Specifically, in this paper, we address the question of how to move towards more sustainable ocean governance aligning with the sustainable development goals (SDGs) and the UN Ocean Decade. We address three major risks to oceans that arise from governance-related issues: (1) the impacts of the overexploitation of marine resources; (2) inequitable distribution of access to and benefits from marine ecosystem services, and (3) inadequate or inappropriate adaptation to changing ocean conditions. The SDGs have been used as an underlying framework to develop these risks. We identify five drivers that may determine how ocean governance evolves, namely formal rules and institutions, evidence and knowledge-based decision-making, legitimacy of decision-making institutions, stakeholder engagement and participation, and empowering communities. These drivers were used to define two alternative futures by 2030: (a) 'Business as Usual'-a continuation of current trajectories and (b) 'More Sustainable Future'-optimistic, transformational, but technically achievable. We then identify what actions, as structured processes, can reduce the three major governance-related risks and lead to the More Sustainable Future. These actions relate to the process of co-creation and implementation of improved, comprehensive, and integrated management plans, enhancement of decision-making processes, and better anticipation and consideration of ambiguity and uncertainty. SUPPLEMENTARY INFORMATION The online version of this article (10.1007/s11160-020-09631-x) contains supplementary material, which is available to authorized users.
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Ocean resource use: building the coastal blue economy. REVIEWS IN FISH BIOLOGY AND FISHERIES 2022; 32:189-207. [PMID: 33679009 PMCID: PMC7922727 DOI: 10.1007/s11160-021-09636-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 01/08/2021] [Indexed: 05/05/2023]
Abstract
Humans have relied on coastal resources for centuries. However, current growth in population and increased accessibility of coastal resources through technology have resulted in overcrowded and often conflicted spaces. The recent global move towards development of national blue economy strategies further highlights the increased focus on coastal resources to address a broad range of blue growth industries. The need to manage sustainable development and future exploitation of both over-utilised and emergent coastal resources is both a political and environmental complexity. To address this complexity, we draw on the perspectives of a multi-disciplinary team, utilising two in depth exemplary case studies in New Zealand and within the Myanmar Delta Landscape, to showcase barriers, pathways and actions that facilitate a move from Business as Usual (BAU) to a future aligned with the Sustainable Development Goals (SDGs) and the UN International Decade of Ocean Science for Sustainable Development 2021-2030. We provide key recommendations to guide interest groups, and nations globally, towards sustainable utilisation, conservation and preservation of their marine environments in a fair and equitable way, and in collaboration with those who directly rely upon coastal ecosystems. We envision a sustainable future driven by conflict mitigation and resolution, where:(i)Change is motivated and facilitated(ii)Coastal ecosystems are co-managed by multiple reliant groups(iii)Networks that maintain and enhance biodiversity are implemented(iv)Decision-making is equitable and based on ecosystem services(v)Knowledge of the marine realm is strengthened-'mapping the ocean of life'(vi)The interests of diverse user groups are balanced with a fair distribution of benefits.
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Food for all: designing sustainable and secure future seafood systems. REVIEWS IN FISH BIOLOGY AND FISHERIES 2022; 32:101-121. [PMID: 34092936 PMCID: PMC8164055 DOI: 10.1007/s11160-021-09663-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 05/21/2021] [Indexed: 05/19/2023]
Abstract
UNLABELLED Food from the sea can make a larger contribution to healthy and sustainable diets, and to addressing hunger and malnutrition, through improvements in production, distribution and equitable access to wild harvest and mariculture resources and products. The supply and consumption of seafood is influenced by a range of 'drivers' including ecosystem change and ocean regulation, the influence of corporations and evolving consumer demand, as well as the growing focus on the importance of seafood for meeting nutritional needs. These drivers need to be examined in a holistic way to develop an informed understanding of the needs, potential impacts and solutions that align seafood production and consumption with relevant 2030 Sustainable Development Goals (SDGs). This paper uses an evidence-based narrative approach to examine how the anticipated global trends for seafood might be experienced by people in different social, geographical and economic situations over the next ten years. Key drivers influencing seafood within the global food system are identified and used to construct a future scenario based on our current trajectory (Business-as-usual 2030). Descriptive pathways and actions are then presented for a more sustainable future scenario that strives towards achieving the SDGs as far as technically possible (More sustainable 2030). Prioritising actions that not only sustainably produce more seafood, but consider aspects of access and utilisation, particularly for people affected by food insecurity and malnutrition, is an essential part of designing sustainable and secure future seafood systems. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s11160-021-09663-x.
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Abstract
Humans have relied on coastal resources for centuries. However, current growth in population and increased accessibility of coastal resources through technology have resulted in overcrowded and often conflicted spaces. The recent global move towards development of national blue economy strategies further highlights the increased focus on coastal resources to address a broad range of blue growth industries. The need to manage sustainable development and future exploitation of both over-utilised and emergent coastal resources is both a political and environmental complexity. To address this complexity, we draw on the perspectives of a multi-disciplinary team, utilising two in depth exemplary case studies in New Zealand and within the Myanmar Delta Landscape, to showcase barriers, pathways and actions that facilitate a move from Business as Usual (BAU) to a future aligned with the Sustainable Development Goals (SDGs) and the UN International Decade of Ocean Science for Sustainable Development 2021-2030. We provide key recommendations to guide interest groups, and nations globally, towards sustainable utilisation, conservation and preservation of their marine environments in a fair and equitable way, and in collaboration with those who directly rely upon coastal ecosystems. We envision a sustainable future driven by conflict mitigation and resolution, where:(i)Change is motivated and facilitated(ii)Coastal ecosystems are co-managed by multiple reliant groups(iii)Networks that maintain and enhance biodiversity are implemented(iv)Decision-making is equitable and based on ecosystem services(v)Knowledge of the marine realm is strengthened-'mapping the ocean of life'(vi)The interests of diverse user groups are balanced with a fair distribution of benefits.
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The future of ocean governance. REVIEWS IN FISH BIOLOGY AND FISHERIES 2022; 32:253-270. [PMID: 33456210 PMCID: PMC7802408 DOI: 10.1007/s11160-020-09631-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 12/11/2020] [Indexed: 05/06/2023]
Abstract
UNLABELLED Ocean governance is complex and influenced by multiple drivers and actors with different worldviews and goals. While governance encompasses many elements, in this paper we focus on the processes that operate within and between states, civil society and local communities, and the market, including industry. Specifically, in this paper, we address the question of how to move towards more sustainable ocean governance aligning with the sustainable development goals (SDGs) and the UN Ocean Decade. We address three major risks to oceans that arise from governance-related issues: (1) the impacts of the overexploitation of marine resources; (2) inequitable distribution of access to and benefits from marine ecosystem services, and (3) inadequate or inappropriate adaptation to changing ocean conditions. The SDGs have been used as an underlying framework to develop these risks. We identify five drivers that may determine how ocean governance evolves, namely formal rules and institutions, evidence and knowledge-based decision-making, legitimacy of decision-making institutions, stakeholder engagement and participation, and empowering communities. These drivers were used to define two alternative futures by 2030: (a) 'Business as Usual'-a continuation of current trajectories and (b) 'More Sustainable Future'-optimistic, transformational, but technically achievable. We then identify what actions, as structured processes, can reduce the three major governance-related risks and lead to the More Sustainable Future. These actions relate to the process of co-creation and implementation of improved, comprehensive, and integrated management plans, enhancement of decision-making processes, and better anticipation and consideration of ambiguity and uncertainty. SUPPLEMENTARY INFORMATION The online version of this article (10.1007/s11160-020-09631-x) contains supplementary material, which is available to authorized users.
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Food for all: designing sustainable and secure future seafood systems. REVIEWS IN FISH BIOLOGY AND FISHERIES 2022; 32:101-121. [PMID: 34092936 DOI: 10.22541/au.160322471.16891119/v1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 05/21/2021] [Indexed: 05/23/2023]
Abstract
UNLABELLED Food from the sea can make a larger contribution to healthy and sustainable diets, and to addressing hunger and malnutrition, through improvements in production, distribution and equitable access to wild harvest and mariculture resources and products. The supply and consumption of seafood is influenced by a range of 'drivers' including ecosystem change and ocean regulation, the influence of corporations and evolving consumer demand, as well as the growing focus on the importance of seafood for meeting nutritional needs. These drivers need to be examined in a holistic way to develop an informed understanding of the needs, potential impacts and solutions that align seafood production and consumption with relevant 2030 Sustainable Development Goals (SDGs). This paper uses an evidence-based narrative approach to examine how the anticipated global trends for seafood might be experienced by people in different social, geographical and economic situations over the next ten years. Key drivers influencing seafood within the global food system are identified and used to construct a future scenario based on our current trajectory (Business-as-usual 2030). Descriptive pathways and actions are then presented for a more sustainable future scenario that strives towards achieving the SDGs as far as technically possible (More sustainable 2030). Prioritising actions that not only sustainably produce more seafood, but consider aspects of access and utilisation, particularly for people affected by food insecurity and malnutrition, is an essential part of designing sustainable and secure future seafood systems. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s11160-021-09663-x.
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Suivi écologique des récifs coralliens des stations IFRECOR de 2001 à 2006 en Martinique. REVUE D'ÉCOLOGIE (LA TERRE ET LA VIE) 2008. [DOI: 10.3406/revec.2008.1399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Measurements of the proton elastic-form-factor ratio mu pG p E/G p M at low momentum transfer. PHYSICAL REVIEW LETTERS 2007; 99:202002. [PMID: 18233135 DOI: 10.1103/physrevlett.99.202002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Indexed: 05/25/2023]
Abstract
High-precision measurements of the proton elastic form-factor ratio, mu pG p E/G p M, have been made at four-momentum transfer, Q2, values between 0.2 and 0.5 GeV2. The new data, while consistent with previous results, clearly show a ratio less than unity and significant differences from the central values of several recent phenomenological fits. By combining the new form-factor ratio data with an existing cross-section measurement, one finds that in this Q2 range the deviation from unity is primarily due to G p E being smaller than expected.
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Quantitative investigation of the ozonolysis reaction. X. On the kinetics of the reaction of ozone with ring-substituted styrenes in carbon tetrachloride solution. J Am Chem Soc 2002. [DOI: 10.1021/ja01053a039] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Oral vinorelbine pharmacokinetics and absolute bioavailability study in patients with solid tumors. Ann Oncol 2001; 12:1643-9. [PMID: 11822766 DOI: 10.1023/a:1013180903805] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Vinorelbine is a vinca alkaloid obtained by hemisynthesis, which makes the molecule more lipophilic than the other vincas. An injectable formulation is already marketed for the treatment of non small cell lung cancer (NSCLC) and advanced breast cancer (ABC). A new oral form has been developed and its file registration is being submitted. As part of its development, a clinical study was conducted to determine the absolute bioavailability and pharmacokinetics of oral vinorelbine administered as softgel capsules, and to evaluate its safety profile compared with intravenous administration. PATIENTS AND METHODS Thirty-two patients with solid tumours were included in the study. Patients fasted and were randomised to receive vinorelbine on day 1, either as a 20 minute intravenous (i.v.) infusion of 25 mg/m2 or as softgel capsules at a dose of 80 mg/m2. Patients were treated with the alternate route after a one week wash-out period. Blood and urine samples for pharmacokinetic analysis were collected during each vinorelbine administration. Safety was assessed after each administration using the CALGB/expanded CTC classification. RESULTS Twenty-four patients were eligible for pharmacokinetic evaluation. Oral vinorelbine was rapidly absorbed at 80 mg/m2 (Tmax 1.4 +/- 0.7 h) and showed a bioavailability of 43 +/- 14, and close to 40% based on AUC(last) and AUC(inf), respectively. A bioequivalence analysis was conducted on dosage-normalised blood exposures. Equivalence was demonstrated between 80 mg/m2 oral and 30 mg/m2 i.v., and between 60 mg/m2 oral and 25 mg/m2 i.v. The inter-individual variability was equivalent for both routes (CV: 38% and 39% for oral and i.v., respectively). A correlation was found in both methods between AUClast and % nadir variation in white blood cells (WBC) and polymorphonuclears (PMN). More cases of neutropenia (all grades pooled), leucopenia (grades 3-4 only) and nausea (grades 2-3) were induced by 80 mg/m2 oral vinorelbine than by 25 mg/m2 i.v. The greatest intensity of these effects, following oral administration, probably reflects the higher, observed drug exposure. CONCLUSION At therapeutic dosage levels, pharmacokinetic behaviour and safety profiles were similar for both routes. The absolute bioavailability of the oral vinorelbine (new, soft gelatine capsule) was close to 40%. Inter-individual variability in drug exposure was equivalent in both routes. The pharmacokinetic/pharmacodynamic (PK/PD) relationship in haematological toxicity was independent of the routes of administration. Reliable, corresponding doses between oral and i.v. vinorelbine were established, which will result in bioequivalent AUC.
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Abstract
Several chronic inflammatory changes undergone during chronic haemodialysis are associated with increased pro-inflammatory cytokine production. Although generation of anaphylatoxins has been incriminated in the untoward effects of haemodialysis, it is still debated whether anaphylatoxins stimulate monocyte secretion of TNF-alpha and IL-1. We demonstrate that peripheral mononuclear cells isolated from healthy controls and cultured with complement-activated autologous serum or recombinant C5a induced high levels of IL-1, IL-1ra, IL-8 and MCP-1, low levels of TNFalpha and sTNFRII but no IL-10 and MIP-1alpha. Cytokine production by leukocytes was investigated by FACS analysis in six patients dialysed consecutively with three equivalent low permeability membranes known to activate the complement to different degrees: polysulfone (F6HPS), cellulose acetate (CA) and cuprophane (CP). Percentage of leukocytes expressing IL-1, IL-1ra, TNF-alpha and IL-8 is increased in patients dialysed with CP. Moreover, we show for the first time that haemodialysis is associated with the production of cytokines by circulating neutrophils. Predialysis plasma levels of MCP-1 and TNFRII did not increase during the dialysis session at the time when anaphylatoxin generation was highest. Dialysis with membranes that activate the complement to a high extent induce activation of leukocytes which may explain chronic complications associated with dialysing with CP.
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Abstract
Complement activation, neutrophil stimulation, increased cellular adhesiveness, transient leukocyte margination and pulmonary leukostasis take place during hemodialysis with cellulosic dialysis membranes. Several investigators have hypothesized that complement activation is primarily responsible for the acute neutropenia occurring during the early phase of bio-incompatible hemodialysis. We have investigated the relationship between complement activation, levels of expression of CD11b and CD61 integrins on neutrophils and platelets, neutrophil counts and blood gas measurements in patients dialyzed with three types of membranes, known to activate the complement system to a different extent. Polysulfone, cellulose acetate and cuprophane membranes were used subsequently in six patients in a prospective cross-over trial design to reduce inter-individual variability. Increased levels of CD61 and CD11b, as well as neutropenia, were detected regardless of the type of membrane used. We observed a high inter-individual variation with regard to complement activation suggesting varying susceptibility to dialysis membranes. We also report that the kinetics of anaphylatoxin generation were dissociated from those of the upregulation of adhesion molecules, early neutrophil margination and decrease in PaO2 during the first 30 min of hemodialysis. Similar results were obtained with all three types of dialysis membranes. The data strengthen the hypothesis that factors other than complement are involved in the induction of dialysis-related neutropenia and hypoxemia.
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Dissociation between beta-2 microglobulin and IL-1 production in hemodialyzed patients. Nephrol Dial Transplant 1997; 12:2365-74. [PMID: 9394324 DOI: 10.1093/ndt/12.11.2365] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND beta-2 microglobulin is predominant in amyloid deposits in patients undergoing long term hemodialysis. Amyloid accumulation has been ascribed to dialysis membranes, endotoxin contamination of the dialysate, uremia and chronic systemic inflammation associated with enhanced monocytic cytokine production in hemodialyzed patients. Interleukin-1 has been proposed to play a critical role in the induction of beta-2 microglobulin synthesis and release. METHODS We examined if monocytes contribute to beta-2 microglobulin production upon stimulation with inflammatory mediators that are generated during hemodialysis and investigated the production of beta-2 microglobulin by cells from patients, with and without clinical signs of amyloidosis, at the time when patients' monocytes contained maximal intracellular accumulation of IL-1. RESULTS We demonstrated that only monocytes are able to release increased levels of beta-2 microglobulin upon stimulation by IL-1, TNF alpha, C5a and LPS. Increased levels of beta-2 microglobulin were associated with increased levels of beta-2 microglobulin mRNA. Before dialysis session, 20-60% of circulating CD14+ monocytes from patients contained IL-1. At the time when maximal IL-1 production was detected, we showed by RT-PCR increased transcription of IL-1 gene in patients' monocytes. We observed that monocytes from patients with amyloidosis contained higher amounts of IL-1 as compared to monocytes from patients without clinical signs of amyloidosis, but could not secrete increased amounts of beta-2 microglobulin upon LPS-stimulation. CONCLUSIONS Our data indicated that chronic inflammation, as demonstrated by increased intracellular IL-1 expression, is not associated with increased production of beta-2 microglobulin by monocytes from patients on hemodialysis.
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Flow-cytometric assessment of in vivo cytokine-producing monocytes in HIV-infected patients. CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 1997; 83:60-7. [PMID: 9073537 DOI: 10.1006/clin.1996.4323] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We have used two-color flow cytometry to study in vivo monocytic cytokine production at the single-cell level in HIV-infected patients. We demonstrated the presence of intracellular IL-1 alpha, IL-1 beta, IL-1ra, and TNF alpha in circulating CD14+ monocytes from HIV-infected patients. The specificity of intracellular staining with anti-cytokine antibodies was demonstrated by the suppression of the fluorescent signal when staining was performed in the presence of recombinant cytokines. We did not detect any specific intracellular staining when anti-IL-4 antibodies were used since monocytes do not produce IL-4. In vivo intracellular cytokine production of IL-1 alpha, IL-1 beta, IL-1ra, and TNF alpha was higher in monocytes from HIV-infected individuals compared to monocytes from healthy controls; however, only the data concerning IL-1 alpha reached statistical significance. Monocytic cytokines are involved in the regulation of HIV gene expression and may participate in the modulation of the Th1/Th2 balance. The ability to follow the production of a wide range of cytokines by circulating monocytes of HIV-infected patients should allow one to better analyze the role of monocytic cytokines in the pathogenesis of HIV disease.
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[Cell adhesion molecules and the immune system]. ALLERGIE ET IMMUNOLOGIE 1995; 27:106-10. [PMID: 7772244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Cellular interactions are controlled by complex mechanisms which come into play at the receptors on the cell surface (adhesion molecules: selectins, integrins, superfamily of immunoglobulins), the soluble cell mediators (cytokines) and the components of the tissue matrix (fibronectin, collagen, etc.). Disturbance of one of these systems may induce a pathological condition. The physiological state of the individual therefore depends on the balance of all these components. In the development of inflammation, adhesion molecules play an essential role in the localisation of the inflammatory response. At this level, the vascular endothelium, a governing barrier for the exchanges between blood and the tissues, plays an active part in regulation of the transcapillary permeability, control of proliferation of haematopoietic cells and the phases of the inflammatory response. After they have marginated, the active cells migrate by diapedesis towards the site of inflammation by creation of chemotactic signals as the adhesion between the cells is insufficient to induce their migration. The adherence phenomena depend on a process that is strictly controlled by the cytokines and enable intervention of cell-cell reactions and cell-protein recognition of the extra-cellular matrix. Cytokines play a key role in control of the expression and/or avidity of membrane receptors for ligand(s). An appropriate and rapid response of the circulating cells depends on coordination of the train of events that regulate the functional expression of the adhesion molecules. Use of specific antibodies that prevent cell adherence opens very important therapeutic possibilities because a single blockage of cell adhesion can have an immediate direct impact on development of the inflammatory response.
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Mécanisme de la décomposition photosensibilisée au mercure du méthylvinyléther à 2537 Å. CAN J CHEM 1971. [DOI: 10.1139/v71-344] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The study of the mercury Hg6(3P1) photosensitized decomposition of methyl vinyl ether has been studied in a static system at substrate pressures from 10 to 800 Torr. The excited precursor proposed has a calculated lifetime of 1.18 × 10−10 s and its decomposition proceeds almost exclusively through the rupture of the O—CH3 bond. A second primary process is the intramolecular formation of ethylene but it accounts only for 2% of the total ether decomposition. The major products are shown to be formed by free radical reactions and the overall reactivity appears to be very similar to that of the olefins. The results obtained with CH3SH added to the system indicate that the primary radicals are formed with a quantum yield close to unity.
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Spectrométrie de masse des peroxydes organiques. III. Ozonides des styrènes substitués dans le noyau. CAN J CHEM 1970. [DOI: 10.1139/v70-392] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The mass spectrometry of the ozonides of ring substituted styrenes has been studied, with R = p-CH3O, p-CH3, H, p-Cl, m-Cl, and p-NO2. Electron withdrawing substituents favor, in general, the appearance of molecular ions. The intensities of the carbonyl fragments [Formula: see text] from the fragmentation of the molecular ions follow the Hammett relationship (ρ = −0.44), as does the formation of [RC6H4CH2]+ from [M-32]+ (ρ = −1.36) The relative abundance of [M-32]+ to that of the molecular ion is independent of R (ρ ≈ 0). The possible participation of electronically excited states in the primary fragmentation process of the m-chlorostyrene ozonide has been invoked to explain its particular behaviour.
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[Psychosocial readjustment of aged persons]. MAROC MEDICAL 1970; 50:15-7. [PMID: 5511445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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[Psycho-social rehabilitation of the aged]. LES CAHIERS DU COLLEGE DE MEDECINE DES HOPITAUX DE PARIS 1969; 10:1483-5. [PMID: 5378400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Abstract
The mass spectra of some ozonides are reported, and the modes of formation of the major fragment ions tentatively described. The use of 18O-labelled compounds has proven to be useful in establishing fragmentation patterns. It is concluded that these follow a characteristic path, which is common to all the ozonides studied and permits mass spectrometric identification.
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Primary process(es) in the mercury-photosensitized decomposition of dimethyl ether at 2537 Å. CAN J CHEM 1968. [DOI: 10.1139/v68-443] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The mercury-photosensitized decomposition of dimethyl ether has been studied at room temperature and at pressures ranging from 10 to 200 Torr.The formation of an excited dimethyl ether (DME) molecule has been verified by following the rates of formation of methane, ethane, and carbon monoxide with various ether pressures.The study of the variation of the quantum yield of molecular hydrogen formation with absorbed light intensity at high ether pressures has shown that the primary process involves the dissociation of ether molecules into hydrogen atoms and methoxy methyl radicals:[Formula: see text]The results presented in this paper indicate that the excited DME molecule can originate in a radical recombination between hydrogen atoms and methoxy methyl radicals.
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