Ozone as oxidation agent in cyclic activation of biochar

Granular activated carbons were produced from grape seed biochar by cyclic activation with ozone. In each cycle, char was first oxidized by exposure to ozone and then subjected to high temperature in inert atmosphere to desorb oxygen groups formed. The study assessed the influence of operating conditions in the development of porosity, from a starting biochar with narrow microporosity (SBET: 47 m2 g− 1, SDA: 505 m2g− 1) prepared by flash pyrolysis of grape seed at 800 °C. The variables studied were the number of cycles applied and the oxidation and desorption temperatures (250–275 and 850–950 °C, respectively). High oxidation temperatures led to higher burn-off, which was also found to increase with the number of activation cycles. The burn-off needed to achieve a high surface area was lower than in conventional physical activation. After 7–9 activation cycles, activated carbons with SBET higher than 1200 m2 g− 1 and SDA above 1500 m2 g− 1 were obtained. The use of ozone resulted in mainly microporous activated carbons (0.37–0.52 cm3 g− 1) with very low contribution of mesopores (< 0.04–0.07 cm3 g− 1). The mean micropore size increased with the number of activation cycles due to pore widening, while mesopore mean size decreased along the cycles. The activated carbons showed a unique granular morphology with a hollow core and a porous shell, which is maintained even after 10 activation cyclesThe authors greatly appreciatefinancial support from the Spanish Ministerio de Ciencia e Innovación (CTQ2012-32821

Granular mesoporous activated carbons from waste tires by cyclic oxygen chemisorption-desorption

This document is the accepted manuscript version of a published work that appeared in final form in Industrial and Engineering Chemistry Research, © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/ie201499hActivation upon cyclic oxygen chemisorption-desorption has proved to be an efficient way to develop porosity at low burn off from waste tires char. In this work the influence of particle size, desorption temperature, and the number of cycles is studied. Highest values of burnoff and specific surface area (S BET) are obtained for the largest particle diameter (3 mm average) and at intermediate desorption temperature (650 °C). In these conditions S BET values around 500 m 2/g can be achieved at burn-offs of about 30%, and close to 600 m 2/g at around 45% burnoff, with a mean pore size of 10 nm and a micropore volume close to 0.08 cm 3/g. Although the surface area is moderate, the low burnoff and high S BET/burnoff ratio achieved make it possible to maintain initial granular morphology of the particles even after 20 cycles of activationWe greatly appreciate finantial support from the Spanish Ministerio de Educacion y Ciencia through the project CTQ2009-0998

Porous structure and morphology of granular chars from flash and conventional pyrolysis of grape seeds

This work studies the influence of the operating conditions used in the pyrolysis of grape seeds on the morphology and textural properties of the chars resulting. Flash and conventional (283Kmin-1 heating rate) pyrolysis have been used within a wide range of temperature (300-1000°C). The effect of a pretreatment for oil extraction has also been studied. The porous structure of the chars was characterized by adsorption of N2 at 77K, Ar at 77K and 87K, and CO2 at 273K and mercury intrusion porosimetry. The morphology was analyzed by scanning electron microscopy. All the materials prepared revealed an essentially microporous structure, with a poor or even negligible contribution of mesopores. Increasing pyrolysis temperature led to higher specific surface areas and lower pore size. The highest specific surface area values occurred within 700-800°C, reaching up to 500m2g-1 with pore sizes in the 0.4-1.1nm range. No significant morphological changes were observed upon carbonization so that the resulting chars were granular materials of similar size than the starting grape seeds. The hollow core structure of the chars, with most of the material allocated at the periphery of the granules can help to overcome the mass transfer limitations of most common (solid or massive) granular activated carbons. The chars showed a good mechanical strength during attrition tests. These chars can be potential candidates for the preparation of granular carbons molecular sieve or activated carbons raw materialsThe authors greatly appreciate financial support from the Spanish Ministerio de Ciencia e Innovación (CTQ2009-09983

Stability of childhood anxiety disorder diagnoses: a follow-up naturalistic study in psychiatric care

Few studies have examined the stability of major psychiatric disorders in pediatric psychiatric clinical populations. The objective of this study was to examine the long-term stability of anxiety diagnoses starting with pre-school age children through adolescence evaluated at multiple time points. Prospective cohort study was conducted of all children and adolescents receiving psychiatric care at all pediatric psychiatric clinics belonging to two catchment areas in Madrid, Spain, between 1 January, 1992 and 30 April, 2006. Patients were selected from among 24,163 children and adolescents who received psychiatric care. Patients had to have a diagnosis of an ICD-10 anxiety disorder during at least one of the consultations and had to have received psychiatric care for the anxiety disorder. We grouped anxiety disorder diagnoses according to the following categories: phobic disorders, social anxiety disorders, obsessive–compulsive disorder (OCD), stress-related disorders, and "other" anxiety disorders which, among others, included generalized anxiety disorder, and panic disorder. Complementary indices of diagnostic stability were calculated. As much as 1,869 subjects were included and had 27,945 psychiatric/ psychological consultations. The stability of all ICD-10 anxiety disorder categories studied was high regardless of the measure of diagnostic stability used. Phobic and social anxiety disorders showed the highest diagnostic stability, whereas OCD and "other" anxiety disorders showed the lowest diagnostic stability. No significant sex differences were observed on the diagnostic stability of the anxiety disorder categories studied. Diagnostic stability measures for phobic, social anxiety, and "other" anxiety disorder diagnoses varied depending on the age at first evaluation. In this clinical pediatric outpatient sample it appears that phobic, social anxiety, and stress-related disorder diagnoses in children and adolescents treated in community outpatient services may have high diagnostic stability

TiO2:Cex onto Al Clays for Photocatalytic Solar Water Disinfection

A novel methodology was employed to prepare new nanocomposites with photocatalytic properties based on Ce-doped TiO2 nanoparticles arranged over a layered silicate. The catalysts were porous materials formed by exfoliated silicate layers surrounded by anatase nanoparticles. In this way, the anatase was doped by different amounts of Ce, yielding to catalysts with light absorption properties on the visible region. The photocatalytic behavior was tested for different reactions: adsorption and photocatalysis, showing outstanding and promising results for the removal of bacteria by using solar light as an energy source. The influence of the physicochemical properties of the catalyst and the reaction parameters will be studied in detail to manage new catalysts for the disinfection of drinking water

Tranexamic acid attenuates inflammatory response in cardiopulmonary bypass surgery through blockade of fibrinolysis: a case control study followed by a randomized double-blind controlled trial

INTRODUCTION: Extracorporeal circulation induces hemostatic alterations that lead to inflammatory response (IR) and postoperative bleeding. Tranexamic acid (TA) reduces fibrinolysis and blood loss after cardiopulmonary bypass (CPB). However, its effects on IR and vasoplegic shock (VS) are not well known and elucidating these effects was the main objective of this study. METHODS: A case control study was carried out to determine factors associated with IR after CPB. Patients undergoing elective CPB surgery were randomly assigned to receive 2 g of TA or placebo (0.9% saline) before and after intervention. We performed an intention-to-treat analysis, comparing the incidence of IR and VS. We also analyzed several biological parameters related to inflammation, coagulation, and fibrinolysis systems. We used SPSS version 12.2 for statistical purposes. RESULTS: In the case control study, 165 patients were studied, 20.6% fulfilled IR criteria, and the use of TA proved to be an independent protective variable (odds ratio 0.38, 95% confidence interval 0.18 to 0.81; P < 0.01). The clinical trial was interrupted. Fifty patients were randomly assigned to receive TA (24) or placebo (26). Incidence of IR was 17% in the TA group versus 42% in the placebo group (P = 0.047). In the TA group, we observed a significant reduction in the incidence of VS (P = 0.003), the use of norepinephrine (P = 0.029), and time on mechanical ventilation (P = 0.018). These patients showed significantly lower D-dimer, plasminogen activator inhibitor 1, and creatine-kinase levels and a trend toward lower levels of soluble tumor necrosis factor receptor and interleukin-6 within the first 24 hours after CPB. CONCLUSION: The use of TA attenuates the development of IR and VS after CPB. TRIAL REGISTRATION NUMBER: ISRCTN05718824

Biomass-Derived Microporous Carbon Materials with an Open Structure of Cross-Linked Sub-microfibers with Enhanced Adsorption Characteristics

This document is the accepted manuscript version of a published work that appeared in final form in Energy and Fuels, © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.6b02112Moringa oleifera seed shells exhibit a unique structure of cross-linked sub-microfibers (0.5-1.5 μm diameter) with a well-connected macroporous network. Controlled pyrolysis (500-800 °C) and cyclic activation of the precursor provided a porous carbon material with a structure that minimizes mass-transfer constraints. Under both slow (10 °C/min-1) and flash pyrolysis, the structure was preserved, while a significant microporosity was developed. By flash pyrolysis (700-800 °C), a material with enhanced characteristics for potential application as a molecular sieve (SDA = 450-470 m2 g-1, and SBET = 5 m2 g-1) was obtained. Cyclic activation of carbonized shells, consisting of an oxygen chemisorption stage (180 °C) followed by a desorption stage in an inert atmosphere (450-900 °C), resulted in a controlled development of microporosity upon successive activation cycles. After 10 activation cycles, respective SDA and SBET values of 1172 and 761 m2 g-1 were obtained. Higher development of the surface area and a wider distribution of micropores was observed when the desorption stage was carried out at 900 °C. The development of the surface area was achieved at low burnoff (22-33%), thus preserving the structure of the material. Thanks to its unique structure, the material obtained exhibited enhanced characteristics for gas sorption as a result of diminished mass-transfer limitations, assessed through the kinetics of carbon dioxide adsorption runs at ambient conditionsThe authors greatly appreciate financial support from the Spanish Ministerio de Economía y Competitividad (CTQ2012-32821

Fine‐tuning modulation of oxidation-mediated posttranslational control of Bradyrhizobium diazoefficiens FixK2 transcription factor

FixK2 is a CRP/FNR‐type transcription factor that plays a central role in a sophisticated regulatory network for the anoxic, microoxic and symbiotic lifestyles of the soybean endosymbiont Bradyrhizobium diazoefficiens. Apart of the balanced expression of the fixK2 gene under microoxic conditions (induced by the two‐component regulatory system FixLJ and negatively auto‐repressed), FixK2 activity is posttranslationally controlled by proteolysis, and by oxidation of a singular cysteine residue (C183) near its DNA‐binding domain. To simulate permanent oxidation of FixK2, we replaced C183 for aspartic acid. Purified C183D FixK2 protein showed both low DNA binding and in vitro transcriptional activation from the promoter of the fixNOQP operon, required for respiration under symbiosis. However, in a B. diazoefficiens strain coding for C183D FixK2, expression of a fixNOQP’‐‘lacZ fusion was similar to that in the wild type, when both strains were grown microoxically. The C183D FixK2 encoding strain also showed a wild‐type phenotype in symbiosis with soybeans, and increased fixK2 gene expression levels and FixK2 protein abundance in cells. These two latter observations together with a global transcriptional profile of the microoxically cultured C183D FixK2 encoding strain suggest the existence of a finely tuned regulatory strategy to counterbalance the oxidation‐mediated inactivation of FixK2 in vivo

High serum levels of tissue inhibitor of matrix metalloproteinase-1 during the first week of a malignant middle cerebral artery infarction in non-surviving patients

Background: Higher circulating levels of tissue inhibitor of matrix metalloproteinases (TIMP)-1 early after ischemic stroke have been associated with lower survival. The objectives of this study were to determine serum TIMP-1 levels during the first week of a severe cerebral infarction in surviving and non-surviving patients, and whether those levels during the first week could be used as a mortality biomarker for these patients. Methods: We included patients with severe malignant middle cerebral artery infarction (MMCAI) defined as computer tomography showing ischaemic changes in more than 50% of the middle cerebral artery territory and Glasgow Coma Scale (GCS) ≤ 8. We measured serum levels of matrix metalloproteinases (MMP)-9 and TIMP-1. End-point study was 30-day mortality. Results: We found higher TIMP-1 concentrations at days 1 (p < 0.001), 4 (p = 0.001), and 8 (p = 0.03) of MMCAI in nonurviving (n = 34) than in surviving (n = 34) patients. We found lower serum MMP-9 concentrations at day 1 (p = 0.03) of MMCAI and no significant differences at days 4 and 8. ROC curve analysis of TIMP-1 concentrations performed at days 1, 4, and 8 of MMCAI showed an area under curve to predict 30-day mortality of 81% (p < 0.001), 80% (p < 0.001) and 72% (p = 0.07) respectively. Conclusions: The new findings of our study were that non-surviving MMCAI patients showed higher serum TIMP-1 levels during the first week of MMCAI that surviving patients, and those levels during the first week of MMCAI could be used as mortality biomarkers