Boosting High-Performance in Lithium-Sulfur Batteries via Dilute Electrolyte.

Polysulfide shuttle effects, active material losses, formation of resistive surface layers, and continuous electrolyte consumption create a major barrier for the lightweight and low-cost lithium-sulfur (Li-S) battery adoption. Tuning electrolyte composition by using additives and most importantly by substantially increasing electrolyte molarity was previously shown to be one of the most effective strategies. Contrarily, little attention has been paid to dilute and super-diluted LiTFSI/DME/DOL/LiNO3 based-electrolytes, which have been thought to aggravate the polysulfide dissolution and shuttle effects. Here we challenge this conventional wisdom and demonstrate outstanding capabilities of a dilute (0.1 mol L-1 of LiTFSI in DME/DOL with 1 wt. % LiNO3) electrolyte to enable better electrode wetting, greatly improved high-rate capability, and stable cycle performance for high sulfur loading cathodes and low electrolyte/sulfur ratio in Li-S cells. Overall, the presented study shines light on the extraordinary ability of such electrolyte systems to suppress short-chain polysulfide dissolution and polysulfide shuttle effects.

Aqueous Dispersions of Graphene from Electrochemically Exfoliated Graphite.

A facile and environmentally friendly synthetic strategy for the production of stable and easily processable dispersions of graphene in water is presented. This strategy represents an alternative to classical chemical exfoliation methods (for example the Hummers method) that are more complex, harmful, and dangerous. The process is based on the electrochemical exfoliation of graphite and includes three simple steps: 1) the anodic exfoliation of graphite in (NH4 )2 SO4 , 2) sonication to separate the oxidized graphene sheets, and 3) reduction of oxidized graphene to graphene. The procedure makes it possible to convert around 30 wt % of the initial graphite into graphene with short processing times and high yields. The graphene sheets are well dispersed in water, have a carbon/oxygen atomic ratio of 11.7, a lateral size of about 0.5-1 µm, and contain only a few graphene layers, most of which are bilayer sheets. The processability of this type of aqueous dispersion has been demonstrated in the fabrication of macroscopic graphene structures, such as graphene aerogels and graphene films, which have been successfully employed as absorbents or as electrodes in supercapacitors, respectively.

Prevalence and correlates of young people's sexual aggression perpetration and victimisation in 10 European countries: a multi-level analysis.

Data are presented on young people's sexual victimisation and perpetration from 10 European countries (Austria, Belgium, Cyprus, Greece, Lithuania, the Netherlands, Poland, Portugal, Slovakia and Spain) using a shared measurement tool (N = 3480 participants, aged between 18 and 27 years). Between 19.7 and 52.2% of female and between 10.1 and 55.8% of male respondents reported having experienced at least one incident of sexual victimisation since the age of consent. In two countries, victimisation rates were significantly higher for men than for women. Between 5.5 and 48.7% of male and 2.6 and 14.8% of female participants reported having engaged in a least one act of sexual aggression perpetration, with higher rates for men than for women in all countries. Victimisation rates correlated negatively with sexual assertiveness and positively with alcohol use in sexual encounters. Perpetration rates correlated positively with attitudes condoning physical dating violence and with alcohol use in men, and negatively with sexual assertiveness in women. At the country level, lower gender equality in economic power and in the work domain was related to higher male perpetration rates. Lower gender equality in political power and higher sexual assertiveness in women relative to men were linked to higher male victimisation rates.

[Microbiological diagnosis of viral hepatitis]. / Diagnóstico microbiológico de las hepatitis virales.

Liver inflammation or hepatitis has many different causes, both infectious and non-infectious. Among the former, viral infection is responsible for at least half of all hepatitis worldwide. Different viruses have been described with primary tropism for liver tissue. These microorganisms have been successively named with letters of the alphabet: A, B, C, D, E and G. The aim of this paper is to review this heterogeneous group of viruses in its most basic aspects, including clinical implications, treatment, main control, and prophylactic measures and, of special interest, diagnostic approaches, both serological and molecular, which are used for their detection, quantification and characterization.

Eco-Friendly Synthesis of 3D Disordered Carbon Materials for High-Performance Dual Carbon Na-Ion Capacitors.

An eco-friendly and sustainable salt-templating approach was proposed for the production of anode materials with a 3D sponge-like structure for sodium-ion capacitors using gluconic acid as carbon precursor and sodium carbonate as water-removable template. The optimized carbon material combined porous thin walls that provided short diffusional paths, a highly disordered microstructure with dilated interlayer spacing, and a large oxygen content, all of which facilitated Na ion transport and provided plenty of active sites for Na adsorption. This material provided a capacity of 314 mAh g-1 at 0.1 A g-1 and 130 mAh g-1 at 10 A g-1 . When combined with a 3D highly porous carbon cathode (SBET ≈2300 m2 g-1 ) synthesized from the same precursor, the Na-ion capacitor showed high specific energy/power, that is 110 Wh kg-1 at low power and still 71 Wh kg-1 at approximately 26 kW kg-1 , and a good capacity retention of 70 % over 10000 cycles.

Co nanoparticles inserted into a porous carbon amorphous matrix: the role of cooling field and temperature on the exchange bias effect.

We report unusual cooling field dependence of the exchange bias in oxide-coated cobalt nanoparticles embedded within the nanopores of a carbon matrix. The size-distribution of the nanoparticles and the exchange bias coupling observed up to about 200 K between the Co-oxide shell (∼3-4 nm) and the ferromagnetic Co-cores (∼4-6 nm) are the key to understand the magnetic properties of this system. The estimated values of the effective anisotropy constant and saturation magnetization obtained from the fit of the zero-field cooling and field cooling magnetization vs. temperature curves agree quite well with those of the bulk fcc-Co.

Mesoporous carbon capsules as electrode materials in electrochemical double layer capacitors.

The performance of mesoporous carbon capsules as electrode materials in electrochemical double layer capacitors (EDLCs) was evaluated in the presence of a variety of electrolytes, including room temperature ionic liquids (ILs).

More Sustainable Chemical Activation Strategies for the Production of Porous Carbons.

The preparation of porous carbons attracts a great deal of attention given the importance of these materials in many emerging applications, such as hydrogen storage, CO2 capture, and energy storage in supercapacitors and batteries. In particular, porous carbons produced by applying chemical activation methods are preferred because of the high pore development achieved. However, given the environmental risks associated with conventional activating agents such as KOH, the development of greener chemical activation methodologies is an important objective. This Review summarizes recent progress in the production of porous carbons by using more sustainable strategies based on chemical activation. The use of less-corrosive chemical agents as an alternative to KOH is thoroughly reviewed. In addition, progress achieved to date by using emerging self-activation methodologies applied to organic salts and biomass products is also discussed.

Adult Attachment, Conflict Resolution Style and Relationship Quality among Spanish Young-adult Couples.

The evidence of the interrelationships between adult attachment, conflict resolution style and relationship quality in couple relationships shows some inconsistencies and it is mostly based on English-speaking adult samples, as well as on individuals' rather than on both couple members' reports. Therefore, the aim was to examine the associations between adult attachment, conflict resolution style and relationship quality from a dyadic approach. A sample of 405 heterosexual young couples completed online the brief version of the Experiences in Close Relationships-Revised Questionnaire, the respondent version of the Conflict Resolution Styles Inventory, and a 4-item measure of relationship quality. Avoidance attachment showed a stronger negative correlation than anxiety with relationship quality. Withdrawal and conflict engagement styles were more highly correlated with avoidance and anxiety, respectively. At a dyadic level, relationship quality was negatively predicted by actor avoidance attachment and positively predicted by partner relationship quality. No actor or partner effects of conflict resolution style on relationship quality were observed. Overall, partners with higher attachment anxiety and avoidance reported more dysfunctional conflict resolution styles and less satisfaction with the relationship.

Development and validation of a population-based prediction scale for osteoporotic fracture in the region of Valencia, Spain: the ESOSVAL-R study.

BACKGROUND: Today, while there are effective drugs that reduce the risk of osteoporotic fracture, yet there are no broadly accepted criteria that can be used to estimate risks and decide who should receive treatment. One of the actual priorities of clinical research is to develop a set of simple and readily-available clinical data that can be used in routine clinical practice to identify patients at high risk of bone fracture, and to establish thresholds for therapeutic interventions. Such a tool would have high impact on healthcare policies. The main objective of the ESOSVAL-R is to develop a risk prediction scale of osteoporotic fracture in adult population using data from the Region of Valencia, Spain. STUDY DESIGN: An observational, longitudinal, prospective cohort study, undertaken in the Region of Valencia, with an initial follow-up period of five years; SUBJECTS: 14,500 men and women over the age of 50, residing in the Region and receiving healthcare from centers where the ABUCASIS electronic clinical records system is implanted; SOURCES OF DATA: The ABUCASIS electronic clinical record system, complemented with hospital morbidity registers, hospital Accidents & Emergency records and the Regional Ministry of Health's mortality register; Measurement of results: Incident osteoporotic fracture (in the hip and/or major osteoporotic fracture) during the study's follow-up period. Independent variables include clinical data and complementary examinations; ANALYSIS: 1) Descriptive analysis of the cohorts' baseline data; 2) Upon completion of the follow-up period, analysis of the strength of association between the risk factors and the incidence of osteoporotic fracture using Cox's proportional hazards model; 3) Development and validation of a model to predict risk of osteoporotic fracture; the validated model will serve to develop a simplified scale that can be used during routine clinical visits. DISCUSSION: The ESOSVAL-R study will establish a prediction scale for osteoporotic fracture in Spanish adult population. This scale not only will constitute a useful prognostic tool, but also it will allow identifying intervention thresholds to support treatment decision-making in the Valencia setting, based mainly on the information registered in the electronic clinical records.

Straightforward synthesis of Sulfur/N,S-codoped carbon cathodes for Lithium-Sulfur batteries.

An upgrade of the scalable fabrication of high-performance sulfur-carbon cathodes is essential for the widespread commercialization of this technology. Herein we present a simple, cost-effective and scalable approach for the fabrication of cathodes comprising sulfur and high-surface area, N,S-codoped carbons. The method involves the use of a sulfur salt, i.e. sodium thiosulfate, as activating agent, sulfur precursor and S-dopant, and polypyrrole as carbon precursor and N-dopant. In this way, the production of the porous host and the incorporation of sulfur are combined in the same procedure. The porous hosts thus produced have BET surface areas in excess of 2000 m2 g-1, a micro-mesoporous structure, as well as sulfur and nitrogen contents of 5-6 wt% and ~2 wt%, respectively. The elemental sulfur content in the composites can be precisely modulated in the range of 24 to ca. 90 wt% by controlling the amount of sodium thiosulfate used. Remarkably, these porous carbons are able to accommodate up to 80 wt% sulfur exclusively within their porosity. When analyzed in lithium-sulfur batteries, these sulfur-carbon composites show high specific capacities of 1100 mAh g-1 at a low C-rate of 0.1 C and above 500 mAh g-1 at a high rate of 2 C for sulfur contents in the range of 50-80 wt%. Remarkably, the composites with 51-65 wt% S can still provide above 400 mAh g-1 at an ultra-fast rate of 4 C (where a charge and discharge cycle takes only ten minutes). The good rate capability and sulfur utilization was additionally assessed for cathodes with a high sulfur content (65-74%) and a high sulfur loading (>5 mg cm-2). In addition, cathodes of 4 mg cm-2 successfully cycled for 260 cycles at 0.2 C showed only a low loss of 0.12%/cycle.

Chemical and structural properties of carbonaceous products obtained by hydrothermal carbonization of saccharides.

Carbon-rich-quick scheme: A carbon-rich solid product made up of uniform micrometer-sized spheres of tunable diameter has been synthesized by the hydrothermal carbonization of saccharides. These microspheres possess a core-shell chemical structure based on the different nature of the oxygen functionalities between the core and the outer layer (see figure).A carbon-rich solid product, here denoted as hydrochar, has been synthesized by the hydrothermal carbonization of three different saccharides (glucose, sucrose, and starch) at temperatures ranging from 170 to 240 degrees C. This material is made up of uniform spherical micrometer-sized particles that have a diameter in the 0.4-6 mum range, which can be modulated by modifying the synthesis conditions (i.e., the concentration of the aqueous saccharide solution, the temperature of the hydrothermal treatment, the reaction time, and type of saccharide). The formation of the carbon-rich solid through the hydrothermal carbonization of saccharides is the consequence of dehydration, condensation, or polymerization and aromatization reactions. The microspheres thus obtained possess, from a chemical point of view, a core-shell structure consisting of a highly aromatic nucleus (hydrophobic) and a hydrophilic shell containing a high concentration of reactive oxygen functional groups (i.e., hydroxyl/phenolic, carbonyl, or carboxylic).

Pore Characteristics for Efficient CO2 Storage in Hydrated Carbons.

Development of new approaches for carbon dioxide (CO2) capture is important in both scientific and technological aspects. One of the emerging methods in CO2 capture research is based on the use of gas-hydrate crystallization in confined porous media. Pore dimensions and surface functionality of the pores play important roles in the efficiency of CO2 capture. In this report, we summarize work on several porous carbons (PCs) that differ in pore dimensions that range from supermicropores to mesopores, as well as surfaces ranging from hydrophilic to hydrophobic. Water was imbibed into the PCs, and the CO2 uptake performance, in dry and hydrated forms, was determined at pressures of up to 54 bar to reveal the influence of pore characteristics on the efficiency of CO2 capture and storage. The final hydrated carbon materials had H2O-to-carbon weight ratios of 1.5:1. Upon CO2 capture, the H2O/CO2 molar ratio was found to be as low as 1.8, which indicates a far greater CO2 capture capacity in hydrated PCs than ordinarily seen in CO2-hydrate formations, wherein the H2O/CO2 ratio is 5.72. Our mechanistic proposal for attainment of such a low H2O/CO2 ratio within the PCs is based on the finding that most of the CO2 is captured in gaseous form within micropores of diameter <2 nm, wherein it is blocked by external CO2-hydrate formations generated in the larger mesopores. Therefore, to have efficient high-pressure CO2 capture by this mechanism, it is necessary to have PCs with a wide pore size distribution consisting of both micropores and mesopores. Furthermore, we found that hydrated microporous or supermicroporous PCs do not show any hysteretic CO2 uptake behavior, which indicates that CO2 hydrates cannot be formed within micropores of diameter 1-2 nm. Alternatively, mesoporous and macroporous carbons can accommodate higher yields of CO2 hydrates, which potentially limits the CO2 uptake capacity in those larger pores to a H2O/CO2 ratio of 5.72. We found that high nitrogen content prevents the formation of CO2 hydrates presumably due to their destabilization and associated increase in system entropy via stronger noncovalent interactions between the nitrogen functional groups and H2O or CO2.

Boosting the Oxygen Reduction Electrocatalytic Performance of Nonprecious Metal Nanocarbons via Triple Boundary Engineering Using Protic Ionic Liquids.

The oxygen reduction reaction (ORR) in aqueous media plays a critical role in sustainable and clean energy technologies such as polymer electrolyte membrane and alkaline fuel cells. In this work, we present a new concept to improve the ORR performance by engineering the interface reaction at the electrocatalyst/electrolyte/oxygen triple-phase boundary using a protic and hydrophobic ionic liquid and demonstrate the wide and general applicability of this concept to several Pt-free catalysts. Two catalysts, Fe-N codoped and metal-free N-doped carbon electrocatalysts, are used as a proof of concept. The ionic liquid layer grafted at the nanocarbon surface creates a water-equilibrated secondary reaction medium with a higher O2 affinity toward oxygen adsorption, promoting the diffusion toward the catalytic active site, while its protic character provides sufficient H+/H3O+ conductivity, and the hydrophobic nature prevents the resulting reaction product water from accumulating and blocking the interface. Our strategy brings obvious improvements in the ORR performance in both acid and alkaline electrolytes, while the catalytic activity of FeNC-nanocarbon outperforms commercial Pt-C in alkaline electrolytes. We believe that this research will pave new routes toward the development of high-performance ORR catalysts free of noble metals via careful interface engineering at the triple point.

Signatures of clustering in superparamagnetic colloidal nanocomposites of an inorganic and hybrid nature.

The individual and co-operative properties of inorganic and hybrid superparamagnetic colloidal nanocomposites that satisfy all the requirements of magnetic carriers in the biosciences and/or catalysis fields are been studied. Essential to the success of this study is the selection of suitable synthetic routes (aerosol and nanocasting) that allow the preparation of materials with different matrix characteristics (carbon, silica, and polymers with controlled porosity). These materials present magnetic properties that depend on the average particle size and the degree of polydispersity. Finally, the analysis of the co-operative behavior of samples allows for the detection of signatures of clustering, which are closely related to the textural characteristics of samples and the methodology used to produce the magnetic carriers.

Optimization of the Pore Structure of Biomass-Based Carbons in Relation to Their Use for CO2 Capture under Low- and High-Pressure Regimes.

A versatile chemical activation approach for the fabrication of sustainable porous carbons with a pore network tunable from micro- to hierarchical micro-/mesoporous is hereby presented. It is based on the use of a less corrosive and less toxic chemical, i.e., potassium oxalate, rather than the widely used KOH. The fabrication procedure is exemplified for glucose as precursor, although it can be extended to other biomass derivatives (saccharides) with similar results. When potassium oxalate alone is used as activating agent, highly microporous carbons are obtained (SBET ≈ 1300-1700 m2 g-1). When a melamine-mediated activation process is used, hierarchical micro-/mesoporous carbons with surface areas as large as 3500 m2 g-1 are obtained. The microporous carbons are excellent adsorbents for CO2 capture at low pressure and room temperature, able to adsorb 4.2-4.5 mmol CO2 g-1 at 1 bar and 1.1-1.4 mmol CO2 g-1 at 0.15 bar. However, the micro-/mesoporous carbons provide record-high room temperature CO2 uptakes at 30 bar of 32-33 mmol g-1 CO2 and 44-49 mmol g-1 CO2 at 50 bar. The findings demonstrate the key relevance of pore size in CO2 capture, with narrow micropores having the leading role at pressures <1 bar and supermicropores/small mesopores at high pressures. In this regard, the fabrication strategy presented here allows fine-tuning of the pore network to maximize both the overall CO2 uptake and the working capacity at any target pressure.

Sexual Coercion Perpetration and Victimization: Gender Similarities and Differences in Adolescence.

Sexual coercion is a worldwide health problem that endangers the well-being of those involved. In the same line of the most recent and comprehensive studies, this study sought to investigate the extent of sexual coercion, both perpetration and victimization, among male and female adolescents. Moreover, it jointly analyzed the predictive power of different variables that have been considered as useful to design preventive programs. For this purpose, a cross-sectional study, using proportional stratified cluster sampling, was performed and 1,242 Spanish adolescents (15-19 years old) were surveyed. Results show that both genders had reported committing and suffering sexual coercion. However, perpetration was reported more often by males: no significant gender difference was found in victimization. It was also concluded that need for control and power, normative beliefs about sexual coercion, hostile sexism, negative alcohol expectancies, and sociosexual orientation were significant predictors of perpetration for both genders. Concerning victimization, need for control and power and normative beliefs were found to be significant predictors for males and females, as were negative alcohol expectancies and sexual esteem, though only for males. According to these results, both genders can be both perpetrators and victims of sexual coercion in adolescence, but not to the same extent. Moreover, preventive programs should include activities related to perpetration and victimization, taking into account the effectiveness of their components to intervene with male and female adolescents.

[Prevalence of vulnerability and protective factors of sexual victimization]. / Prevalencia y factores de vulnerabilidad y protección de la victimización sexual en la relaciones con los iguales en las mujeres Universitarias Españolas.

English language abstract not available at time of publication.

A Green Approach to High-Performance Supercapacitor Electrodes: The Chemical Activation of Hydrochar with Potassium Bicarbonate.

Sustainable synthesis schemes for the production of porous carbons with appropriate textural properties for use as supercapacitor electrodes are in high demand. In this work a greener option to the widely used but corrosive KOH is proposed for the production of highly porous carbons. Hydrochar products are used as carbon precursors. It is demonstrated that a mild alkaline potassium salt such as potassium bicarbonate is very effective to generate porosity in hydrochar to lead to materials with large surface areas (> 2000 m(2) g(-1) ) and a tunable pore size distribution. Furthermore, the use of KHCO3 instead of KOH gives rise to a significant 10 % increase in the yield of activated carbon, and the spherical morphology of hydrochar is retained, which translates into better packing properties and reduced ion diffusion distances. These features lead to a supercapacitor performance that can compete with, and even surpass, that of KOH-activated hydrochar in a variety of electrolytes.

Fe-N-Doped Carbon Capsules with Outstanding Electrochemical Performance and Stability for the Oxygen Reduction Reaction in Both Acid and Alkaline Conditions.

High surface area N-doped mesoporous carbon capsules with iron traces exhibit outstanding electrocatalytic activity for the oxygen reduction reaction in both alkaline and acidic media. In alkaline conditions, they exhibit more positive onset (0.94 V vs RHE) and half-wave potentials (0.83 V vs RHE) than commercial Pt/C, while in acidic media the onset potential is comparable to that of commercial Pt/C with a peroxide yield lower than 10%. The Fe-N-doped carbon catalyst combines high catalytic activity with remarkable performance stability (3500 cycles between 0.6 and 1.0 V vs RHE), which stems from the fact that iron is coordinated to nitrogen. Additionally, the newly developed electrocatalyst is unaffected by the methanol crossover effect in both acid and basic media, contrary to commercial Pt/C. The excellent catalytic behavior of the Fe-N-doped carbon, even in the more relevant acid medium, is attributable to the combination of chemical functions (N-pyridinic, N-quaternary, and Fe-N coordination sites) and structural properties (large surface area, open mesoporous structure, and short diffusion paths), which guarantees a large number of highly active and fully accessible catalytic sites and rapid mass-transfer kinetics. Thus, this catalyst represents an important step forward toward replacing Pt catalysts with cheaper alternatives. In this regard, an alkaline anion exchange membrane fuel cell was assembled with Fe-N-doped mesoporous carbon capsules as the cathode catalyst to provide current and power densities matching those of a commercial Pt/C, which indicates the practical applicability of the Fe-N-carbon catalyst.