Synthesis of Purine-Based Ionic Liquids and Their Applications.

Bio-based ionic liquids (ILs) are being increasingly sought after, as they are more sustainable and eco-friendly. Purines are the most widely distributed, naturally occurring N-heterocycles, but their low water-solubility limits their application. In this work, four purines (theobromine, theophylline, xanthine, and uric acid) were combined with the cation tetrabutylammonium to synthesize bio-based ILs. The physico-chemical properties of the purine-based ILs were characterized, including their melting and decomposition temperatures and water-solubility. The ecotoxicity against the microalgae Raphidocelis subcapitata was also determined. The ILs show good thermal stability (>457 K) and an aqueous solubility enhancement ranging from 53- to 870-fold, in comparison to their respective purine percursors, unlocking new prospects for their application where aqueous solutions are demanded. The ecotoxicity of these ILs seems to be dominated by the cation, and it is similar to chloride-based IL, emphasizing that the use of natural anions does not necessarily translate to more benign ILs. The application of the novel ILs in the formation of aqueous biphasic systems (ABS), and as solubility enhancers, was also evaluated. The ILs were able to form ABS with sodium sulfate and tripotassium citrate salts. The development of thermoresponsive ABS, using sodium sulfate as a salting-out agent, was accomplished, with the ILs having different thermosensitivities. In addition, the purine-based ILs acted as solubility enhancers of ferulic acid in aqueous solution.

Gynaecological cancer in Caribbean women: data from the French population-based cancer registries of Martinique, Guadeloupe and French Guiana (2007-2014).

BACKGROUND: For the first time, we present regional-level cancer incidence and world-standardized mortality rates for cancers for Martinique, Guadeloupe and French Guiana. METHODS: For Martinique, Guadeloupe and French Guiana, incidence data come from population-based cancer registries, and cover the periods 2007-2014, 2008-2014 and 2010-2014 respectively. Standardized incidence and mortality rates were calculated using the world population. RESULTS: In the 3 regions, all cancers combined represent 3567 new cases per year, of which 39.8% occur in women, and 1517 deaths per year (43.4% in women). Guadeloupe and Martinique present similar world-standardized incidence rates. Among gynaecological cancers, breast cancer, the second most common cancer type in the 3 regions, has an incidence rate 35 to 46% lower than in mainland France. On the other hand, cervical cancer has a higher incidence rate, particularly in French Guiana. For both endometrial cancer and ovarian cancer, no significant differences in incidence rates are found compared to mainland France. Regarding mortality, world-standardized mortality rates are similar between Guadeloupe and Martinique, and higher than in French Guiana. This situation compares favourably with mainland France (all cancers). Among gynaecological cancers, the mortality rate is lower for breast cancer in all regions compared to mainland France, and also lower for ovarian cancer in Martinique and Guadeloupe, but higher (albeit non-significantly) in French Guiana. CONCLUSION: The ethno-geographic and socio-demographic characteristics in this population of mainly Afro-Caribbean origin could partially explain these disparities. Major disparities exist for certain cancer sites: excess incidence and excess mortality for cervical cancer; lower, but increasing incidence of breast cancer.

Aggregation of Plate-like Colloids Induced by Charged Polymer Chains: Organization at the Nanometer Scale Tuned by Polymer Charge Density.

We study the aggregation of charged plate-like colloids, Na-montmorillonite clays, in the presence of ionenes, oppositely charged polymer chains. The choice of the charged polymer allows tuning its linear charge density to match/mismatch the average charge separation on the clay surfaces. We assess the nanoscale structure of the aggregates formed by small-angle X-ray and neutron scattering. The nanoscale features of the formed clay aggregates are dominated by the presence of a stacking peak, giving clear evidence for the formation of clay tactoids, that is, a face-to-face aggregation geometry of the clay platelets. The chain charge density of ionenes influences not only the stacking repeat distance within the clay tactoids but also the extent of stacking and abundance of the tactoids. We may distinguish two regimes as a function of clay and ionene polymer charge densities (ρc and ρp, respectively). The first regime applies to ρp > ρc and ρp ≈ ρc, that is, for highly and "matching" charged chains. Under these conditions, the intercalated chains lie in a flat conformation within the tactoids, irrespective of the ionic strength (within the range studied, i.e., up to 0.05 M NaBr). For weakly charged chains, ρp < ρc, undulation of the ionene chains within the tactoid is seen. The degree of undulation increases with ionic strength due to the decreasing persistence length of the ionene chains. The extent of stacking (5-10 platelets per tactoid) is a general feature of all the systems, and its origin remains unknown. The system corresponding to the closest match in charge separations on the clay surface and on the polymer chain (ρp ≈ ρc) features the highest abundance of tactoids. This coincides with the highest macroscopic density as deduced from simple visual inspection of sediment volumes. This leads to the open question regarding the link between the density at the nanoscale and the macroscopic density and sedimentation behavior of the aggregate.

Structural and Morphological Description of Sn/SnOx Core-Shell Nanoparticles Synthesized and Isolated from Ionic Liquid.

The potential application of high capacity Sn-based electrode materials for energy storage, particularly in rechargeable batteries, has led to extensive research activities. In this scope, the development of an innovative synthesis route allowing to downsize particles to the nanoscale is of particular interest owing to the ability of such nanomaterial to better accommodate volume changes upon electrochemical reactions. Here, we report on the use of room temperature ionic liquid (i.e., [EMIm+][TFSI-]) as solvent, template, and stabilizer for Sn-based nanoparticles. In such a media, we observed, using Cryo-TEM, that pure Sn nanoparticles can be stabilized. Further washing steps are, however, mandatory to remove residual ionic liquid. It is shown that the washing steps are accompanied by the partial oxidation of the surface, leading to a core-shell structured Sn/SnOx composite. To understand the structural features of such a complex architecture, HRTEM, Mössbauer spectroscopy, and the pair distribution function were employed to reveal a crystallized ß-Sn core and a SnO and SnO2 amorphous shell. The proportion of oxidized phases increases with the final washing step with water, which appeared necessary to remove not only salts but also the final surface impurities made of the cationic moieties of the ionic liquid. This work highlights the strong oxidation reactivity of Sn-based nanoparticles, which needs to be taken into account when evaluating their electrochemical properties.

The Singular Epidemiology of Plasmacytoma and Multiple Myeloma in French Guiana.

BACKGROUND: The objective was to review a decade of plasmacytoma (PC) and multiple myeloma (MM) data from French Guiana, and to study its spatial and temporal trends. METHODS: This was a retrospective study of MM and PC between January 2005 and December 2014 using cancer registry data, including age-standardized incidence and mortality rates. RESULTS: There were 110 cases of PC and MM (62 women and 48 men), representing the eighth most frequent malignancy in French Guiana. PC and MM were much more common in females. In men, 79% of cases occurred at ≥55 years, and in women, 90% of cases occurred at ≥50 years. The median age at diagnosis was 60 years for men and 66 years for women, while it was 72 years for men and 75 years for women in mainland France. The incidence rate standardized to the world population was 5.9 patients of PC and MM per 100,000 men/year and 7.8 per 100,000 women/year. CONCLUSIONS: In our territory, the incidence of PC and MM was higher and patients were diagnosed at a substantially younger age than in mainland France. Women had a greater incidence than men, and there was an increasing temporal trend of incidence among women. African ancestry and the frequency of obesity, notably among women, could have contributed to this observation.

Efficient method for in situ agitation of liquids directly inside NMR spectrometer.

The objective of the method is to allow agitation and fast homogenization of liquid systems in NMR tubes, directly inside the NMR spectrometer. The setup makes it possible to record spectra of samples that are macroscopically not stable, as dispersions of large particles. It makes also possible to fasten the homogeneization of liquid during a reaction or a phase transition. In the present paper, the method has been evaluated using homogeneous liquid extraction (HLLE). This configuration can also be used to introduce gases in different systems to perform various types of experiments. The set up consists in a Teflon tube inserted in the NMR tube bringing gas that yields agitation by bubbling. The gas flow is tuned using an electronically operated valve connected to gas line and to the NMR console. The method details how to reach proper homogenization without any perturbation, as liquid leaks.•An easy method for agitation of liquids inside NMR spectrometers.•The set up can be used for the insertion of gases in the NMR tube inside the spectrometer.•The method allows the study of the mixing of biphasic systems by NMR techniques.

Cervical cancer incidence in French Guiana: South American.

For the first time, the incidence of cervical cancer was estimated in French Guiana, an overseas French Territory of South America. A certified cancer registry collected exhaustive data on cervical cancer between 2003 and 2005. The age-standardized rate of invasive cervical cancer was 30.3 per 100,000 women. Women from rural areas had lesions with a significantly greater extension than women from urban areas. Compared to South American figures, the standardized incidence of cervical cancer seemed relatively high when viewed in comparison with the gross domestic product per capita. The curative orientation of the health system should move from opportunistic screening for cervical cancer to organized screening, with an emphasis on the rural parts of French Guiana.

Gastric Cancer Incidence and Mortality in French Guiana: South American or French?

PURPOSE: Gastric cancer is a frequent cancer in the tropics. The objective was to review a decade of gastric cancer data, and to study its spatial and temporal trends. METHODS: The cancer registry of French Guiana compiled exhaustive data on gastric cancer throughout French Guiana between 2005 and 2014. Age-standardized incidence and mortality rates were computed. RESULTS: With 187 new cases recorded, gastric cancer ranked 6th (4.3%). It was more frequent in men than in women. The median age at diagnosis was 62 years for men and 65 years for women. The incidence rate standardized to the world population over the period 2005-2014 was 14.3 cases of gastric cancer per 100,000 man-years and 7.3 per 100,000 woman-years. The death rate from gastric cancer, standardized to the world population over the period 2005-2014, was 8.6 deaths from gastric cancer per 100,000 man-years and 3.4 per 100,000 women-years. These measures were lower than what is reported in Latin America, similar to Martinique and Guadeloupe-two tropical French territories-and higher than in France. CONCLUSIONS: Gastric cancer affected more males and the median age was younger than in France. Standardized incidence and mortality rates for gastric cancer in French Guiana were between those of France and those of Latin America, and they were comparable to those of the French West Indies. The downward trend in a context of rapid economic growth suggests further gains that could be achieved by improving electricity, water, and sanitation coverage throughout the territory despite challenging geography, and better access to care and Helicobacter pylori eradication.

Burden of gastric and digestive cancers in the French Caribbean: perspectives from population-based cancer registries of Martinique, Guadeloupe and French Guiana (2007-2014).

OBJECTIVES: Data from population-based cancer registries contribute to improving our knowledge of digestive cancer trends worldwide. In this study, we present cancer incidence and mortality in Guadeloupe, French Guiana and Martinique for the periods 2008-2014, 2010-2014 and 2007-2014, respectively. DESIGN: Data were extracted from population-based cancer registries. World-standardised incidence (WSI) and mortality (WSM) rates were calculated. Main digestive cancers were analysed, including oesophagus, stomach, colorectum, liver and pancreas cancers. SETTING: This study was performed based on data from French Territories in the Caribbean. RESULTS: We observed a lower-incidence compared with mainland France, except for stomach cancer for which the incidence is high, with significant standardised incidence ratios in men and women at 1.90 vs 2.29 for Guadeloupe and French Guiana and 1.58 vs 2.31 for Martinique. We found a lower-mortality, except for stomach cancer for which the mortality remains high, with significant mortality ratios in men and women at 2.10 vs 2.74 for Guadeloupe, 1.64 vs 1.79 for French Guiana and 2.05 vs 2.53 for Martinique. Overall, these three regions have similar WSI and WSM rates which remain lower than those in mainland France. We noticed an overall high incidence and high mortality in men compared with women as in France. CONCLUSIONS: There is a high incidence of stomach cancer in French overseas territories. Publication of these data contributed to expanding knowledge on the epidemiology of world cancers with data from the Caribbean zone.

Urological Cancers in French Overseas Territories: A Population-Based Cancer Registry Pooled Analysis in Martinique, Guadeloupe and French Guiana (2007-2014).

PURPOSE: Prostate cancer is the most common cancer in the Caribbean. We present world-standardized incidence (WSI) and mortality (WSM) rates for urological cancers for French overseas territories. MATERIALS AND METHODS: Standardized incidence ratio (SIR) and standardized mortality ratio (SMR) were calculated for 2008-2014, 2007-2014 and 2010-2014 in Guadeloupe, Martinique and French Guiana. RESULTS: For prostate cancer, in Guadeloupe and Martinique, the WSI rates are among the highest in the world (173.0 and 164.5 per 100,000 person-years) and 94.4 in French Guiana. Mortality remains more than twice that observed in mainland France, at 23.0 in Guadeloupe and Martinique, and 16.9 in French Guiana. For bladder cancer, WSI rates were 5.9, 4.9 and 4.1 in men, and 1.9, 1.4 and 1.3 in women, in French Guiana, Guadeloupe and Martinique. WSM rates from bladder varied from 1.5 in French Guiana to 1.8 in Guadeloupe and 2.0 in Martinique in men. In women, it ranges from 0.2 in French Guiana to 0.5 in Guadeloupe and 1.1 in Martinique. Regarding kidney, WSI rates in men are 4.3 in Martinique, 5.2 in Guadeloupe and 6.1 in French Guiana, and 2.3, 2.5 and 3.4, respectively, in women. Mortality rates in men were 1.7 in Guadeloupe, 1.4 in Martinique, and 1.5 in French Guiana, while in women, rates were 0.8 in Guadeloupe and Martinique and 0.6 in French Guiana. All these rates are lower than in mainland France. CONCLUSIONS: Identifying the profile of patients with urological cancers is key to understanding the needs of patients in these regions.

Incidence and mortality of cervical cancer in French Guiana: Temporal and spatial trends.

Objectives: Cervical cancer is the second most frequent cancer among women in French Guiana. The objective was to review a decade of cervical cancer data, and to study spatial and temporal trends. Study design: The design was retrospective and descriptive. Methods: The cancer registry of French Guiana compiled exhaustive data on cervical cancer throughout French Guiana between 2005 and 2015. Age-standardized incidence and mortality were computed and mapped to identify priority areas. Results: With 232 new cases recorded in French Guiana between 2005 and 2014 (23 annual cases), cervical cancer ranked 5th among all incident cancers (11%) and was the 2nd most frequent cancer in women (12% of cancers among women). The standardized incidence rate over the period 2005-2014 was 23.8 cases of cervical cancer per 100 000 woman-years. Between 2005-2009 and 2010-2014 the incidence of cervical cancer decreased from 26.26 cases per 100 000 to 22.66 cases per 100 000 and the mortality rate from cervical cancer decreased from 6 deaths per 100 000 to 3.2 deaths per 100 000.Within French Guiana, the standardized incidence rates were very heterogenous with the highest rates in remote areas. The standardized death rate from cervical cancer over the 2005-2014 decade was 4.4 cases per 100 000 woman-years. Conclusions: The present results suggest there has been progress in French Guiana, but there are still areas where screening is challenging and should be expanded. The recent authorization of HPV testing is an opportunity that could help health professionals achieve this goal. HPV vaccination -with a nonavalent vaccine-is also an important public health endeavor that could alleviate the burden of cervical cancer among the cohorts of women benefitting from it.

Organisation of clay nanoplatelets in a polyelectrolyte-based hydrogel.

We investigate the organisation of clay nanoplatelets within a hydrogel based on modified ionenes, cationic polyelectrolytes forming physically crosslinked hydrogels induced by hydrogen bonding and π-π stacking. Combination of small angle X-ray and neutron scattering (SAXS, SANS) reveals the structure of the polyelectrolyte network as well as the organisation of the clay additives. The clay-free hydrogel network features a characteristic mesh-size between 20 and 30 nm, depending on the polyelectrolyte concentration. Clay nanoplatelets inside the hydrogel organise in a regular face-to-face stacking manner, with a large repeat distance, following rather closely the hydrogel mesh-size. The presence of the nanoplatelets does not modify the hydrogel mesh size. Further, the clay-compensating counterions (Na+, Ca2+ or La3+) and the clay type (montmorillonite, beidellite) both have a significant influence on nanoplatelet organisation. The degree of nanoplatelet ordering in the hydrogel is very sensitive to the negative charge location on the clay platelet (different for each clay type). Increased nanoplatelet ordering leads to an improvement of the elastic properties of the hydrogel. On the contrary, the presence of dense clay aggregates (tactoids), induced by multi-valent clay counterions, destroys the hydrogel network as seen by the reduction of the elastic modulus of the hydrogel.

Predictive Factors of the Survival of Women With Invasive Breast Cancer in French Guiana: The Burden of Health Inequalities.

BACKGROUND: The prognosis of patients with breast cancer in French Guiana is worse than in France, with 23 deaths per 100 incident cases versus 17 per 100 in metropolitan France. This study aimed to compare the relative survival of patients with invasive breast cancer (IBC) between women from French Guiana and metropolitan France and to determine risk factors influencing breast cancer survival in French Guiana. MATERIALS AND METHODS: Data were collected from the Cancer Registry of French Guiana. We compared the relative survival of women with IBC between French Guiana and metropolitan France. We used the Cox proportional hazard regression to evaluate the effect of prognostic factors on cancer-specific mortality in French Guiana. RESULTS: We included all 269 cases of IBC in women diagnosed in French Guiana between 2003 and 2009. The overall 5-year relative survival rate of patients with IBC was 79% in French Guiana and 86% in metropolitan France. The place of birth (foreign country vs. French territory), the tumor stage at the time of diagnosis, the mode of diagnosis (symptoms vs. screening), the presence of hormone receptors in the tumor, and the histologic type were the variables associated with survival differences. None of the other study variables were significantly associated with prognosis. CONCLUSION: Access to care for migrants is challenging, which leads to health inequalities. Early detection through prevention programs is crucial to increase IBC survival, notably for foreign-born patients.

Ion transfer processes at ionic liquid based redox active drop deposited on an electrode surface.

Ion transfer across the boundary formed at an ionic liquid drop deposited on an electrode immersed in aqueous solution, generated by electrochemical redox reaction at the electrode-ionic liquid interface, is studied to obtain information about the ability of anions to be transferred into a room temperature ionic liquid.

Concentrated assemblies of magnetic nanoparticles in ionic liquids.

Maghemite (γ-Fe2O3) nanoparticles (NPs) can be successfully dispersed in a protic ionic liquid, ethylammonium nitrate (EAN), by transfer from aqueous dispersions into EAN. As the aqueous systems are well controlled, several parameters can be tuned. Their crucial role towards the interparticle potential and the structure of the dispersions is evidenced: (i) the size of the NPs tunes the interparticle attraction monitoring dispersions to be either monophasic or gas-liquid-like phase separated; (ii) the nature of the initial counterion in water (here sodium, lithium or ethylammonium) and the amount of added water (<20 vol%) modulate the interparticle repulsion. Very concentrated dispersions with a volume fraction of around 25% are obtained thanks to the gas-liquid-like phase separations. Such conclusions are derived from a fine structural and dynamical study of the dispersions on a large range of spatial scales by coupling several techniques: chemical analyses, optical microscopy, dynamic light scattering, magneto-optic birefringence and small angle scattering.

Synthesis of tin nanocrystals in room temperature ionic liquids.

The aim of this work was to investigate the synthesis of tin nanoparticles (NPs) or tin/carbon composites, in room temperature ionic liquids (RTILs), that could be used as structured anode materials for Li-ion batteries. An innovative route for the synthesis of Sn nanoparticles in such media is successfully developed. Compositions, structures, sizes and morphologies of NPs were characterized by high-energy X-ray diffraction (HEXRD), X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM). Our findings indicated that (i) metallic tetragonal ß-Sn was obtained and (ii) the particle size could be tailored by tuning the nature of the RTILs, leading to nano-sized spherical particles with a diameter ranging from 3 to 10 nm depending on synthesis conditions. In order to investigate carbon composite materials for Li-ion batteries, Sn nanoparticles were successfully deposited on the surface of multi-wall carbon nanotubes (MWCNT). Moreover, electrochemical properties have been studied in relation to a structural study of the nanocomposites. The poor electrochemical performances as a negative electrode in Li-ion batteries is due to a significant amount of RTIL trapped within the pores of the nanotubes as revealed by XPS investigations. This dramatically affected the gravimetric capacity of the composites and limited the diffusion of lithium. The findings of this work however offer valuable insights into the exciting possibilities for synthesis of novel nano-sized particles and/or alloys (e.g. Sn-Cu, Sn-Co, Sn-Ni, etc.) and the importance of carbon morphology in metal pulverization during the alloying/dealloying process as well as prevention of ionic liquid trapping.

The epidemiology of breast cancer in French Guiana 2003-2006.

For the first time the incidence and mortality of breast cancer were estimated in French Guiana, an overseas French Territory of South America. A certified cancer registry collected exhaustive data on breast cancer between 2003 and 2005. The age-standardized rate of breast cancer was 47.1 per 100 000 women. The age-standardized death rate was 11.0 per 100 000 women. Although the standardized incidence and death rates were lower than in metropolitan France and South America, the ratio between incidence and mortality showed that the prognosis of breast cancer in French Guiana was worse than in metropolitan France (23 deaths per 100 incident cases versus 17 deaths per 100 incident cases, respectively). The demographics of French Guiana, suggests that mass organized screening may benefit from lowering the age of its target population.

Potential of long chain ionic liquids for on-line sample concentration techniques: application to micelle to solvent stacking.

The performance of micelle to solvent stacking (MSS) in capillary zone electrophoresis (CZE) was improved for anionic analytes using the long chain ionic liquid type cationic surfactant 1-dodecyl-3-methylimidazolium tetrafluoroborate (C12-MIM-BF4). The peak heights and corrected peak areas of the test profens and herbicides were enhanced up to 59 and 110-fold, respectively when compared to typical injection. These were up to 10 times better compared to the surfactant cetyltrimethyl ammonium bromide as MSS carrier. This performance was attributed to the properties of C12-MIM-BF4. MSS requires micelles in the sample for transport of bound analytes to a stacking boundary that contains an organic solvent for effective electrophoretic mobility reversal. The ionic liquid micelles provided better analyte transport properties that resulted from its hydrophobic and pi-pi interaction capabilities. The good solubility of the ionic liquid in high percentages of organic solvent also facilitated a more effective reversal of mobility. The LODs obtained for the test analytes were from 0.06 to 0.12 µg/mL. The linearity R² values in terms of peak height and corrected area were ≥ 0.99. The interday repeatabilities (%RSD, n=10,) were 0.5-2.2% for retention time, 1.9-4.7% for corrected areas and 4.1-6.4% for peak heights.

Redox-switched amphiphilic ionic liquid behavior in aqueous solution.

A new redox amphiphilic ionic liquid (AIL) containing ferrocene as a redox-active group was synthesized, 1-(11-ferrocenylundecyl)-3-methylimidazolium bromide (Fc11MIm+). Adsorption and aggregation of both reduced and oxidized forms of this ferrocenated AIL in aqueous solution were studied by surface tension measurements. The micellization was favored for the reduced ferrocenated AIL (Fc11MIm+) as compared with the oxidized ferrocenated AIL (Fc+11MIm+). Minimum areas at the air/aqueous solution interface were identical whereas limiting surface tensions were slightly different. This corroborated the formation of an expanded monolayer of redox active AIL at the interface. The electrochemical behavior of redox active AIL was investigated. The electrochemical responses of Fc11MIm+ aqueous solution interestingly differed, depending on its concentration. Below the cmc, the electrochemical reaction was dominated by ferrocenated AIL adsorbed onto the electrode surface; then above the cmc, it was controlled by the Fc11MIm+ diffusing to the electrode. For the latter, the electrochemical mechanism was suggested to couple with the disruption reaction of the reduced form micelles.

Determination of aqueous inclusion complexation constants and stoichiometry of alkyl(methyl)-methylimidazolium-based ionic liquid cations and neutral cyclodextrins by affinity capillary electrophoresis.

Affinity CE (ACE) method was developed to characterize the complex formation between seven alkyl(methyl)methylimidazolium-based ionic liquid (IL) cations and eight neutral cyclodextrins (CD). The effective mobility data of the IL cations were processed according to classical nonlinear and linear treatments to obtain the complex stoichiometry and formation constant K. The majority of systems followed a 1:1 complexation stoichiometry model but in four cases a 1:2 stoichiometry was better satisfied. The K values obtained for each IL were compared to elucidate the main influences of IL and CD nature. The availability of these data should lend support to various application areas, including the screening and tailoring of new interactions in the solution for CE.