Electro-oxidation of cyanide on active and non-active anodes: Designing the electrocatalytic response of cobalt spinels

[EN] The feasibility of the electrochemical technologies for wastewater treatment greatly relies on the design of efficient but inexpensive electrocatalysts. It is generally accepted that the so-called ¿non-active¿ anodes (like the boron-doped diamond (BDD) or SnO2-based anodes), producing highly oxidizing hydroxyl radicals, are the most promising candidates for pollutants abatement. In this work, the electrocatalytic performance of various cobalt oxides, pure and doped with Cu or Au, for CN¿ oxidation has been studied and compared with that of conventional graphite, BDD, SnO2-Sb and SnO2-Sb-Pt. The metal oxide electrodes were prepared by thermal decomposition of the salt precursors onto Ti. For the M-doped Co3O4 electrodes, the nominal M/Co ratios were Cu/ Co=0.07¿1.00; and Au/Co=0.05¿0.20. The electrodes were characterized by different techniques (XRD, SEM, EDX, XPS) and their electrocatalytic response was studied by cyclic voltammetry and galvanostatic electrolysis in a H-type cell in aqueous 0.1M NaOH. The obtained results show that the nature of the dopant plays a key role on the electrocatalytic behavior of cobalt spinels. Thus, while Cu catalyzes the CN¿ electro-oxidation, Au declines it. This is explained by the fact that, unlike Au (which segregates as Au-rich particles), Cu is effectively incorporated into the spinel structure by forming a solid solution (CuxCo3-xO4). In this solid solution, atomic scale Cu(spinel)-CN¿ specific interactions occur to catalyze the reaction, whereas in segregated Au particles the oxidation is hindered probably by a too-strong adsorption of cyanide and/or its inaccessibility to oxide active sites. Electrolysis runs have revealed that ¿active¿ over-saturated Cu-doped spinels (Cu/Co=1.00) exhibit higher current efficiencies than conventional graphite and ¿non-active¿ BDD and SnO2-based anodes. Hence, we hereby demonstrate that an inexpensive ¿active¿ electrocatalyst can show even higher efficiency than the most powerful BDD anode. These results highlight the significance of anode design in the application of the electrochemical technique for wastewater treatment.Financial support from the Spanish Ministerio de Economia y Competitividad and FEDER funds (MAT2016-76595-R, IJCI-2014-20012) is gratefully acknowledgedBerenguer, R.; Quijada, C.; La Rosa-Toro, A.; Morallón, E. (2019). Electro-oxidation of cyanide on active and non-active anodes: Designing the electrocatalytic response of cobalt spinels. Separation and Purification Technology. 208:42-50. https://doi.org/10.1016/j.seppur.2018.05.024S425020

Association of Oliguria With Acute Kidney Injury Diagnosis, Severity Assessment, and Mortality Among Patients With Critical Illness

Contexte & Objectifs : A l’heure actuelle, l’insuffisance rénale aiguë (IRA) est définie et classifiée selon la variation de deux paramètres biologiques : la créatinine sérique (sCr) et le débit urinaire (UO). Cependant, la pertinence des critères basés sur l’oligurie est encore contestée. Notre but est de déterminer la contribution de cette oligurie, définie selon les critères KDIGO, dans le diagnostic d’IRA, dans l’évaluation de sa sévérité et dans la prédiction de la mortalité associée. Matériel & Méthodes : Nous avons réalisé une étude de cohorte incluant tous les patients adultes admis dans une unité de soins intensifs multidisciplinaire entre le 1e janvier 2010 et le 15 juin 2020. Ont été exclus les patients qui (1) avaient exprimé oralement ou par écrit une absence de consentement, (2) présentaient une insuffisance rénale terminale (ESKD) sous traitement rénal substitutif (RRT), ou (3) affichaient des données incomplètes empêchant de les classifier (i.e., moins de 6h d’UO ou absence de valeurs de sCr). Nous avons extrait la sCr journalière, le UO horaire ainsi les caractéristiques sociodémographiques et les scores de sévérité de l’ensemble des dossiers médicaux électroniques. La mortalité à long terme a été examinée en recoupant notre base de données avec le registre national suisse des décès. Nous avons déterminé la survenue et la sévérité de chaque IRA, en appliquant de manière stricte et séparée les critères de la classification KDIGO basés sur la sCr et l’UO, puis avons analysé leur concordance statistique. L’influence relative des critères UO sur la mortalité à 90 jours a été évaluée en utilisant un model multivarié prenant en compte les caractéristiques individuelles, les scores de sévérité et les stades KDIGO basés sur la sCr. Des analyses de sensibilité ont été effectuées pour apprécier l’impact des valeurs manquantes en termes de poids, d’UO et de sCr ainsi que l’impact des changements de définition de la créatinine de base. Résultats : Parmi les 15 620 patients inclus dans l’étude [10 330 (66.1%) hommes, âge médian de 65.0 ans (IQR, 53.0 - 75.0), score SAPS médian de 40.0 (IQR, 30.0 - 53.0), suivi médian de 67.0 mois (IQR, 34.0 - 100.0)], 12 143 (77.7%) ont remplis les critères d’IRA. Les critères sCr et UO ont montré une concordance médiocre en termes de diagnostic et de classification de l’IRA (coefficient kappa de Cohen pondéré = 0.36, 95% CI 0.34 - 0.37, p < 0.001). Comparé à l’usage isolé des critères sCr, la considération des critères UO ont permis d’identifier une IRA chez 5630 (36.0%) patients supplémentaires. Ces patients ont rencontré une mortalité à 90 jours plus élevée que les patients sans IRA (respectivement 12.9% et 8.3%, p < 0.001). Avec les analyses multivariées prenant en compte le stade sCr, les comorbidités et la sévérité de la pathologie, les stades urinaires 2 et 3 ont fortement été associés à une mortalité à 90 jours plus élevée [OR 2.4 (1.6 - 3.8), p< 0.001, et 6.2 (3.7 - 10.5), p < 0.001, respectivement]. Ces résultats sont restés significatifs dans toutes les analyses de sensibilité. Conclusions : L’oligurie d’une durée de plus de 12 heures (stade urinaire KDIGO 2 et 3) a été associée à des implications diagnostiques et pronostiques majeures, indépendamment des altérations concomitantes sCr. Les épisodes de plus courte durée (moins de 12h) n’ont pas montré la même significativité pronostique. -- IMPORTANCE The current definition and staging of acute kidney injury (AKI) considers alterations in serum creatinine (sCr) level and urinary output (UO). However, the relevance of oliguria-based criteria is disputed. OBJECTIVE To determine the contribution of oliguria, as defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria, to AKI diagnosis, severity assessment, and short- and long- term outcomes. DESIGN, SETTING, AND PARTICIPANTS This cohort study included adult patients admitted to a multidisciplinary intensive care unit from January 1, 2010, to June 15, 2020. Patients receiving long- term dialysis and those who declined consent were excluded. Daily sCr level and hourly UO measurements along with sociodemographic characteristics and severity scores were extracted from electronic medical records. Long-term mortality was assessed by cross-referencing the database with the Swiss national death registry. The onset and severity of AKI according to the KDIGO classification was determined using UO and sCr criteria separately, and their agreement was assessed. MAIN OUTCOMES AND MEASURES Using a multivariable model accounting for baseline characteristics, severity scores, and sCr stages, the association of UO criteria with 90-day mortality was evaluated. Sensitivity analyses were conducted to assess how missing sCr, body weight, and UO values, as well as different sCr baseline definitions and imputations methods, would affect the main results. RESULTS Among the 15 620 patients included in the study (10 330 men [66.1%] with a median age of 65 [IQR, 53-75] years, a median Simplified Acute Physiology Score II score of 40.0 [IQR, 30.0- 53.0], and a median follow-up of 67.0 [IQR, 34.0-100.0] months), 12 143 (77.7%) fulfilled AKI criteria. Serum creatinine and UO criteria had poor agreement on AKI diagnosis and staging (Cohen weighted κ, 0.36; 95% CI, 0.35-0.37; P < .001). Compared with the isolated use of sCr criteria, consideration of UO criteria enabled identification of AKI in 5630 patients (36.0%). Those patients had a higher 90-day mortality than patients without AKI (724 of 5608 [12.9%] vs 288 of 3462 [8.3%]; P < .001). On multivariable analysis accounting for sCr stage, comorbidities, and illness severity, UO stages 2 and 3 were associated with a higher 90-day mortality (odds ratios, 2.4 [95% CI, 1.6-3.8; P < .001] and 6.2 [95% CI, 3.7-10.5; P < .001], respectively). These results remained significant in all sensitivity analyses. CONCLUSIONS AND RELEVANCE The findings of this cohort study suggest that oliguria lasting more than 12 hours (KDIGO stage 2 or 3) has major AKI diagnostic implications and is associated with outcomes irrespective of sCr elevations

Electrooxidation of cyanide on cobalt oxide anodes

Oxidation of cyanide ions at a Ti/Co3O4 electrode in aqueous base solution has been investigated. The cyclic voltammetric curve for the oxidation of cyanide at Ti/Co3O4 shows a well formed wave prior to oxygen evolution at a potential where the spinel surface itself undergoes oxidation. Using a flow cell it is confirmed that the conversion of cyanide (CN-) to cyanate (CNO-) can be achieved galvanostatically with a reasonable current efficiency. As an example, at a current density of 100 A m(-2), CN- concentration can be lowered from 10 to 0.2 mM with an electric energy consumption of about 18 kWh kg(-1) of CN- oxidized and a global current efficiency of 28.5%. The oxide coating appears to be quite stable during repeated electrolyses

Validation en consultation spécialisée d’un autotest identifiant les patients allergiques aux acariens de la poussière de maison

L’augmentation de la prévalence des allergies durant les dernières décennies et les nombreuses répercussions négatives d’une prise en charge tardive, nous poussent à trouver des moyens diagnostiques plus efficients. L’allergie aux acariens de la poussière de maison représente plus de 75 % des allergies respiratoires pédiatriques. L’objectif de cette étude est de valider en consultation spécialisée le nouvel autotest de la marque ExAller afin d’identifier les sujets allergiques aux acariens de la poussière de maison et de mettre en place une prise en charge adéquate. Une étude prospective non interventionnelle a été réalisée en 2020 sur une population belge de 40 patients âgés de 3 ans et 2 mois à 18 ans et 10 mois. En amont, nous avons expliqué le principe de l’autotest et obtenu le consentement éclairé des parents. Chaque patient a bénéficié d’une anamnèse pour évaluer la probabilité d’allergie aux acariens. Les patients ont également bénéficié de tests allergiques cutanés selon la méthode de prick test, d’une biologie avec immunoglobulines E spécifiques aux acariens de la poussière de maison et l’autotest. La comparaison a été faite entre les résultats de l’autotest, les tests allergiques cutanés et les dosages des immunoglobulines E spécifiques de Dermatophagoides pteronyssinus et farinae. Les résultats donnent une sensibilité de 93,3 % et une spécificité de 100 %. Ils permettent de valider in vivo le nouvel autotest ExAller et de le mettre à disposition des sujets potentiellement allergiques aux acariens de la poussière de maison

Ureaplasma urealyticum, Ureaplasma parvum et Mycoplasma hominis: commensaux ou pathogènes? [Ureaplasma urealyticum, Ureaplasma parvum, and Mycoplasma hominis: commensals or pathogens?]

Mycoplasma hominis, Ureaplasma urealyticum, and Ureaplasma parvum are bacteria commonly found in the urogenital tract. However, their pathogenicity in sexually active or obstetrical patients remains controversial. Therefore, determining the significance of screening and treatment for these organisms is challenging, unlike Mycoplasma genitalium which now has well-defined management guidelines. We conducted a review of the literature to clarify the clinical significance of detecting these micro-organisms. It is crucial to carefully select the few cases that warrant further investigations, in order to mitigate the risks of overdiagnosis and overtreatment

Potential use of carbon felt in gold hydrometallurgy

The use of carbon felt as a three-dimensional electrode appears to be very promising for the recovery of heavy metals, and toxic compounds removal from dilute solutions, considering its favourable physico-chemical properties : high specific surface area, good fluid permeability and compressibility, chemical inertness and good electrical conductivity. This work presents the contribution of the carbon felt electrode in two different steps of the gold cyanidation recovery process : firstly as a cathode for the electrowinning of gold solution obtained after the elution of loaded carbon; secondly as an anode for the electro-oxidation of cyanide ions present at low concentration (200-300mg/l) in waste streams. In the first case, more than 10 kg of gold per m(2) of felt (2000 kg of gold per m(3) of felt) can be loaded at 400 A/m(2) from dilute gold solutions (30 mg/l Au) with classic Faradic yields (6-12 %) and high overall extraction efficiency (> 90 %). The felt homogeneously loaded with adhesive gold deposit can be smelted in an electric furnace without addition of fluxes since the carbon felt decomposes in gaseous products without formation of ashes. In the second case, the cyanide ion concentration can be lowered to as low as 10 mg/l by electro-oxidation to cyanate form (CNO-) at 400 A/m2 in the anodic compartment of a divided cell. The presence of copper ion significantly improves the current efficiency of this electro-oxidation and sharply reduces the oxidation of the carbon felt. Copper ions accelerate the oxidation rate of free cyanide ions through the formation of easily oxidizable complexes owing to a mechanism in which the Cu-I/Cu-II redox couple acts as an electron transfer mediator. (C) 1999 Elsevier Science Ltd. All rights reserved

Pregnancy after kidney transplantation: an observational study on maternal, graft and offspring outcomes in view of current literature.

Pregnancy after kidney transplantation (KTx) is considered to have a high risk of non-negligible complications for the mother, the allograft, and the offspring. With an increased incidence of these pregnancies over the past decades, transplant nephrologists and specialized obstetricians face increasing challenges, with scarce literature regarding long-term outcomes. We retrospectively collected data from all women with at least one live birth pregnancy after KTx who were followed at our tertiary hospital between 2000 and 2021 to study maternal, graft and fetal outcomes. Ten patients underwent 14 live birth pregnancies after KTx. Preponderant maternal complications were stage 1 acute kidney injury (43%), urinary tract infections (UTI, 43%), progression of proteinuria without diagnostic criteria for preeclampsia (29%), and preeclampsia (14%). Median baseline serum creatinine at conception was 126.5 µmol/L [median estimated glomerular filtration rate (eGFR) 49 mL/min/1.73m <sup>2</sup> ], and eGFR tended to be lower than baseline at follow-ups. Overall, there was no increase in preexisting or occurrence of de novo donor-specific antibodies. No graft loss was documented within the 2-year follow-up. There were nine premature births (64%), with a median gestational age of 35.7 weeks. The median birth weight, height, and head circumference were 2,560 g, 45.5 cm, and 32.1 cm, respectively. These measurements tended to improve over time, reaching a higher percentile than at birth, especially in terms of height, but on average remained under the 50th percentile curve. Overall, pregnancies after KTx came with a range of risks for the mother, with a high prevalence of cesarean sections, emergency deliveries, UTI, and preeclampsia, and for the child, with a high proportion of prematurity, lower measurements at birth, and a tendency to stay under the 50th percentile in growth charts. The short- and long-term impact on the allograft seemed reassuring; however, there was a trend toward lower eGFR after pregnancy. With these data, we emphasize the need for a careful examination of individual risks via specialized pre-conception consultations and regular monitoring by a transplant nephrologist and a specialist in maternal-fetal medicine during pregnancy. More data about the long-term development of children are required to fully apprehend the impact of KTx on offspring