Nouveaux composés ternaires à base de magnésium : structure, propriétés de sorption d'hydrogène et propriétés physiques

A drastic reduction of emissions requires a partial or a full phase-out of fossil fuels and switch to renewable based energy production. Hydrogen appears to be a potential candidate to replace hydrocarbon fuels for producing clean energy. In this context, production and storage of hydrogen is one of the key challenges in developing the hydrogen economy.The objective of this thesis is to produce hydrogen from Mg-based materials using (i) hydrolysis and (ii) microwaves methods.The first aim of this thesis is to elaborate Mg-based materials with good hydrolysis kinetics and high yield of hydrogen generation (i.e. reducing the formation of the passivation layer on magnesium). For this study, we focalize essentially on the effect of various additives (Transition metals, Carbon or Oxides) on the hydrolysis reaction of Mg-based materials. The mixtures were prepared by ball milling. Chloride solution (3.5 wt. % NaCl, i.e. sea water) was used as reaction medium to beneficiate of chloride ions effect. Our strategy, to solve the problems related to the low absorption/desorption kinetics (even at high temperature (i.e. 350°C) of Mg-based materials, is based on microwaves energy application. Our second goal for this thesis is to investigate the dehydriding reaction of magnesium hydride catalyzed by carbon (i.e.MgH2 – C) under microwave irradiations. We have studied the effects of microwaves on the kinetics of hydrogen desorption, the morphology and sorption properties of Mg powder after microwave treatment. On the other hand, we have presented another microwaves application which appears very promising: production of fine titanium powder from titanium hydride.L’hydrogène peut être utilisé (et est utilisé depuis peu) comme un vecteur d’énergie propre. Il permet la transition du monde énergétique actuel, basé sur les énergies fossiles, vers le monde énergétique futur basé sur les énergies renouvelables et l’hydrogène. Cette transition ne sera envisageable que lorsque les problématiques liées à la production en masse de l’hydrogène et à son stockage seront résolues.L’objectif de ce travail de thèse est de produire l’hydrogène à partir de matériaux à base de magnésium en utilisant deux méthodes : (i) l’hydrolyse et (ii) la méthode micro-ondes.Notre premier objectif était d’élaborer des matériaux pour lesquels le phénomène de passivation du magnésium serait limité et présenteraient ainsi des rendements de production d’hydrogène optimaux. Le broyage mécanique à haute énergie est utilisé pour élaborer les différents composites à base de magnésium ou de son hydrure (Mg – 10 % en masse Additifs) afin d’accentuer la corrosion de ces derniers. Nous avons essentiellement focalisé nos efforts sur l’effet des additifs (i.e. Métaux de transition, Carbone et Oxydes) sur la réaction d’hydrolyse. Les tests d’hydrolyse ont été effectués dans une solution contenant 35 g/L NaCl (i.e. eau de mer). Notre stratégie, pour la résolution des problèmes de cinétique d’absorption/désorption (très lentes même à haute température (i.e. 350°C)), est basée essentiellement sur l’application de l’énergie micro-ondes. Notre deuxième objectif est donc l’utilisation des micro-ondes pour déshydrurer plus rapidement l’hydrure de magnésium (MgH2 – C) grâce à une élévation de température très rapide par rapport au procédé conventionnel. On a traité l’effet des irradiations micro-ondes sur la cinétique de désorption de mélange MgH2 – C, la morphologie et les propriétés de la poudre après un traitement micro-ondes. D’autre part, nous avons présenté une perspective possible de l’application des micro-ondes : la production de fines poudres de titane à partir de son hydrure

Potential bioactivity of Phoenix dactylifera fruits, leaves, and seeds against prostate and pancreatic cancer cells

The use of functional foods’ phytochemicals in the chemoprevention of different cancer diseases has become one of the hot scientific areas in the clinical nutrition field. For instance, the Khalas palm cultivar (KPC; Phoenix dactylifera) is one of the natural sustainable resources that have high bioactivity and functionality. This study aimed to investigate the antiproliferative activity and mode of action of KPC’s different parts on prostate (Pc3) and pancreatic (panc1) cancer cells at a molecular level. In the methods, KPC’s leaves, seeds, and fruits’ chemical composition and phytochemical analysis were analyzed. Also, the cytotoxic effects of each extract were assessed against pc3 and panc1 cell lines. Besides, induction of apoptosis, cell cycle analysis, and gene expression of both Cap3 and Cap9 were studied. The obtained results indicated that KPC leaves extract exhibited the highest significant (P < 0.01) anti-proliferation activity against the utilized cancer cell lines compared to fruits and seeds extracts. Also, there were significant (P < 0.05) differences in the phenolic contents, flavonoid of compounds, and antioxidant power of the leaves when compared to the seeds and fruits. Additionally, the highest cytotoxic effect (lowest IC50) was recorded with leave extract than seeds and fruits. Meanwhile, the seeds extract induced (P < 0.05) the apoptosis and arrested cells in the G2/M phase as well as up-regulated the gene expression of the apoptotic-related genes (Casp3 and Casp9) compared to the control group. In conclusion, this study showed that the presence of bioactive components in the KPC different parts extracts have the significant ability to induce the apoptotic pathway that could down-regulate the proliferation of prostate (pc3) and pancreatic (panc1) cancer cells. The pathway mechanism of action was induced by the phytol molecule presented in its leaves extract

Global economic burden of unmet surgical need for appendicitis

Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially

Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89.6 per cent) compared with that in countries with a middle (753 of 1242, 60.6 per cent; odds ratio (OR) 0.17, 95 per cent c.i. 0.14 to 0.21, P <0001) or low (363 of 860, 422 per cent; OR 008, 007 to 010, P <0.001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -94 (95 per cent c.i. -11.9 to -6.9) per cent; P <0001), but the relationship was reversed in low-HDI countries (+121 (+7.0 to +173) per cent; P <0001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0.60, 0.50 to 073; P <0.001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries.Peer reviewe

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Global variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone

Hydrogen production from metals hydrides : hydrolysis and microwaves methods

L’hydrogène peut être utilisé (et est utilisé depuis peu) comme un vecteur d’énergie propre. Il permet la transition du monde énergétique actuel, basé sur les énergies fossiles, vers le monde énergétique futur basé sur les énergies renouvelables et l’hydrogène. Cette transition ne sera envisageable que lorsque les problématiques liées à la production en masse de l’hydrogène et à son stockage seront résolues.L’objectif de ce travail de thèse est de produire l’hydrogène à partir de matériaux à base de magnésium en utilisant deux méthodes : (i) l’hydrolyse et (ii) la méthode micro-ondes.Notre premier objectif était d’élaborer des matériaux pour lesquels le phénomène de passivation du magnésium serait limité et présenteraient ainsi des rendements de production d’hydrogène optimaux. Le broyage mécanique à haute énergie est utilisé pour élaborer les différents composites à base de magnésium ou de son hydrure (Mg – 10 % en masse Additifs) afin d’accentuer la corrosion de ces derniers. Nous avons essentiellement focalisé nos efforts sur l’effet des additifs (i.e. Métaux de transition, Carbone et Oxydes) sur la réaction d’hydrolyse. Les tests d’hydrolyse ont été effectués dans une solution contenant 35 g/L NaCl (i.e. eau de mer). Notre stratégie, pour la résolution des problèmes de cinétique d’absorption/désorption (très lentes même à haute température (i.e. 350°C)), est basée essentiellement sur l’application de l’énergie micro-ondes. Notre deuxième objectif est donc l’utilisation des micro-ondes pour déshydrurer plus rapidement l’hydrure de magnésium (MgH2 – C) grâce à une élévation de température très rapide par rapport au procédé conventionnel. On a traité l’effet des irradiations micro-ondes sur la cinétique de désorption de mélange MgH2 – C, la morphologie et les propriétés de la poudre après un traitement micro-ondes. D’autre part, nous avons présenté une perspective possible de l’application des micro-ondes : la production de fines poudres de titane à partir de son hydrure.A drastic reduction of emissions requires a partial or a full phase-out of fossil fuels and switch to renewable based energy production. Hydrogen appears to be a potential candidate to replace hydrocarbon fuels for producing clean energy. In this context, production and storage of hydrogen is one of the key challenges in developing the hydrogen economy.The objective of this thesis is to produce hydrogen from Mg-based materials using (i) hydrolysis and (ii) microwaves methods.The first aim of this thesis is to elaborate Mg-based materials with good hydrolysis kinetics and high yield of hydrogen generation (i.e. reducing the formation of the passivation layer on magnesium). For this study, we focalize essentially on the effect of various additives (Transition metals, Carbon or Oxides) on the hydrolysis reaction of Mg-based materials. The mixtures were prepared by ball milling. Chloride solution (3.5 wt. % NaCl, i.e. sea water) was used as reaction medium to beneficiate of chloride ions effect. Our strategy, to solve the problems related to the low absorption/desorption kinetics (even at high temperature (i.e. 350°C) of Mg-based materials, is based on microwaves energy application. Our second goal for this thesis is to investigate the dehydriding reaction of magnesium hydride catalyzed by carbon (i.e.MgH2 – C) under microwave irradiations. We have studied the effects of microwaves on the kinetics of hydrogen desorption, the morphology and sorption properties of Mg powder after microwave treatment. On the other hand, we have presented another microwaves application which appears very promising: production of fine titanium powder from titanium hydride

Hydrogen production from metals hydrides : hydrolysis and microwaves methods

L’hydrogène peut être utilisé (et est utilisé depuis peu) comme un vecteur d’énergie propre. Il permet la transition du monde énergétique actuel, basé sur les énergies fossiles, vers le monde énergétique futur basé sur les énergies renouvelables et l’hydrogène. Cette transition ne sera envisageable que lorsque les problématiques liées à la production en masse de l’hydrogène et à son stockage seront résolues.L’objectif de ce travail de thèse est de produire l’hydrogène à partir de matériaux à base de magnésium en utilisant deux méthodes : (i) l’hydrolyse et (ii) la méthode micro-ondes.Notre premier objectif était d’élaborer des matériaux pour lesquels le phénomène de passivation du magnésium serait limité et présenteraient ainsi des rendements de production d’hydrogène optimaux. Le broyage mécanique à haute énergie est utilisé pour élaborer les différents composites à base de magnésium ou de son hydrure (Mg – 10 % en masse Additifs) afin d’accentuer la corrosion de ces derniers. Nous avons essentiellement focalisé nos efforts sur l’effet des additifs (i.e. Métaux de transition, Carbone et Oxydes) sur la réaction d’hydrolyse. Les tests d’hydrolyse ont été effectués dans une solution contenant 35 g/L NaCl (i.e. eau de mer). Notre stratégie, pour la résolution des problèmes de cinétique d’absorption/désorption (très lentes même à haute température (i.e. 350°C)), est basée essentiellement sur l’application de l’énergie micro-ondes. Notre deuxième objectif est donc l’utilisation des micro-ondes pour déshydrurer plus rapidement l’hydrure de magnésium (MgH2 – C) grâce à une élévation de température très rapide par rapport au procédé conventionnel. On a traité l’effet des irradiations micro-ondes sur la cinétique de désorption de mélange MgH2 – C, la morphologie et les propriétés de la poudre après un traitement micro-ondes. D’autre part, nous avons présenté une perspective possible de l’application des micro-ondes : la production de fines poudres de titane à partir de son hydrure.A drastic reduction of emissions requires a partial or a full phase-out of fossil fuels and switch to renewable based energy production. Hydrogen appears to be a potential candidate to replace hydrocarbon fuels for producing clean energy. In this context, production and storage of hydrogen is one of the key challenges in developing the hydrogen economy.The objective of this thesis is to produce hydrogen from Mg-based materials using (i) hydrolysis and (ii) microwaves methods.The first aim of this thesis is to elaborate Mg-based materials with good hydrolysis kinetics and high yield of hydrogen generation (i.e. reducing the formation of the passivation layer on magnesium). For this study, we focalize essentially on the effect of various additives (Transition metals, Carbon or Oxides) on the hydrolysis reaction of Mg-based materials. The mixtures were prepared by ball milling. Chloride solution (3.5 wt. % NaCl, i.e. sea water) was used as reaction medium to beneficiate of chloride ions effect. Our strategy, to solve the problems related to the low absorption/desorption kinetics (even at high temperature (i.e. 350°C) of Mg-based materials, is based on microwaves energy application. Our second goal for this thesis is to investigate the dehydriding reaction of magnesium hydride catalyzed by carbon (i.e.MgH2 – C) under microwave irradiations. We have studied the effects of microwaves on the kinetics of hydrogen desorption, the morphology and sorption properties of Mg powder after microwave treatment. On the other hand, we have presented another microwaves application which appears very promising: production of fine titanium powder from titanium hydride

Hydrogen production from metals hydrides : hydrolysis and microwaves methods

L’hydrogène peut être utilisé (et est utilisé depuis peu) comme un vecteur d’énergie propre. Il permet la transition du monde énergétique actuel, basé sur les énergies fossiles, vers le monde énergétique futur basé sur les énergies renouvelables et l’hydrogène. Cette transition ne sera envisageable que lorsque les problématiques liées à la production en masse de l’hydrogène et à son stockage seront résolues.L’objectif de ce travail de thèse est de produire l’hydrogène à partir de matériaux à base de magnésium en utilisant deux méthodes : (i) l’hydrolyse et (ii) la méthode micro-ondes.Notre premier objectif était d’élaborer des matériaux pour lesquels le phénomène de passivation du magnésium serait limité et présenteraient ainsi des rendements de production d’hydrogène optimaux. Le broyage mécanique à haute énergie est utilisé pour élaborer les différents composites à base de magnésium ou de son hydrure (Mg – 10 % en masse Additifs) afin d’accentuer la corrosion de ces derniers. Nous avons essentiellement focalisé nos efforts sur l’effet des additifs (i.e. Métaux de transition, Carbone et Oxydes) sur la réaction d’hydrolyse. Les tests d’hydrolyse ont été effectués dans une solution contenant 35 g/L NaCl (i.e. eau de mer). Notre stratégie, pour la résolution des problèmes de cinétique d’absorption/désorption (très lentes même à haute température (i.e. 350°C)), est basée essentiellement sur l’application de l’énergie micro-ondes. Notre deuxième objectif est donc l’utilisation des micro-ondes pour déshydrurer plus rapidement l’hydrure de magnésium (MgH2 – C) grâce à une élévation de température très rapide par rapport au procédé conventionnel. On a traité l’effet des irradiations micro-ondes sur la cinétique de désorption de mélange MgH2 – C, la morphologie et les propriétés de la poudre après un traitement micro-ondes. D’autre part, nous avons présenté une perspective possible de l’application des micro-ondes : la production de fines poudres de titane à partir de son hydrure.A drastic reduction of emissions requires a partial or a full phase-out of fossil fuels and switch to renewable based energy production. Hydrogen appears to be a potential candidate to replace hydrocarbon fuels for producing clean energy. In this context, production and storage of hydrogen is one of the key challenges in developing the hydrogen economy.The objective of this thesis is to produce hydrogen from Mg-based materials using (i) hydrolysis and (ii) microwaves methods.The first aim of this thesis is to elaborate Mg-based materials with good hydrolysis kinetics and high yield of hydrogen generation (i.e. reducing the formation of the passivation layer on magnesium). For this study, we focalize essentially on the effect of various additives (Transition metals, Carbon or Oxides) on the hydrolysis reaction of Mg-based materials. The mixtures were prepared by ball milling. Chloride solution (3.5 wt. % NaCl, i.e. sea water) was used as reaction medium to beneficiate of chloride ions effect. Our strategy, to solve the problems related to the low absorption/desorption kinetics (even at high temperature (i.e. 350°C) of Mg-based materials, is based on microwaves energy application. Our second goal for this thesis is to investigate the dehydriding reaction of magnesium hydride catalyzed by carbon (i.e.MgH2 – C) under microwave irradiations. We have studied the effects of microwaves on the kinetics of hydrogen desorption, the morphology and sorption properties of Mg powder after microwave treatment. On the other hand, we have presented another microwaves application which appears very promising: production of fine titanium powder from titanium hydride