Incidence and risk factors of adverse events in pediatric hemato-oncological patients: A cohort study.

BACKGROUND: Pediatric hemato-oncological (HO) patients are highly susceptible to the occurrence of adverse events (AE), nevertheless few research has been done in this field. Our aim was to describe the incidence, type, severity and preventability of AE in these patients, including bone marrow transplant (BMT) patients, and to identify patient's risk factors for having an AE. METHODS: Retrospective cohort study. Children under 18yo hospitalized at the HO or BMT ward in 2016 were eligible for the study. Type of AE, severity and preventability were described as absolute and relative frequencies. Cumulative incidence of patients with at least one AE (CI_AE) and the rate of occurrence of all AE were calculated. Risk factors (sex, recovery probability, comorbidities and being a BMT patient) were analyzed using logistic regression. RESULTS: 114 patients were included, 58% were male, average age was 8.7yo and 25 were BMT patients. 44 had at least one AE, with CI_AE of 38.6% (95%CI 29.7-47.5). Overall rate of occurrence of AE was 2.5 cases per 100 patients-day (95%CI 2.15-2.98). For BMT and non-BMT patients they were 2.8 (95%CI 2.2-3.6) and 2.5 (95%CI 1.98-3.1) respectively. Healthcare related infection was the most frequent AE. Most AE were moderate and with high preventability. Being a BMT patient was the only independent factor associated with the occurrence of at least one AE (OR=11.5, p<0.001). CONCLUSIONS: Our findings suggest that AE tend to be moderate and preventable in HO pediatric patients. BMT patients seem to be at greater risk of having an AE. Strategies focused on patient safety need to account for their specific characteristics.

[Hypothalamotomy in patients with treatment-resistant aggressiveness: functional outcomes]. / Hipotalamotomía en pacientes con agresividad refractaria: resultados funcionales.

INTRODUCTION: Aggressiveness is part of the behavioural manifestations associated with some mental disorders; it is a symptom that is difficult to manage and is often resistant to pharmacological measures. Surgery for behavioural disorders emerges as a therapeutic alternative. This procedure consists in performing interventions on different structures of the limbic system in order to correct the alteration of the circuit involved in producing the symptoms. AIM: To describe the clinical outcomes of a posterior hypothalamotomy with gamma knife to control aggressiveness in 20 patients resistant to treatment, who underwent surgery at the Imbanaco Medical Centre between 2013 and 2018. PATIENTS AND METHODS: The severity of the aggressiveness was quantified using the Overt Aggression Scale (OAS) and the Clinical Global Impression Scale (CGI-SI), and its functional impact is evaluated using the Global Assessment of Functioning scale (GAF). RESULTS: Control over aggressiveness was observed in all patients treated by posterior hypothalamotomy with gamma knife, evidenced by a decrease in the scores on the OAS and CGI-SI and an improvement in the GAF. CONCLUSIONS: Posterior hypothalamotomy gives rise to few complications, is a safe procedure and offers good results, suggesting that it could be a good alternative treatment in cases of treatment-resistant aggressiveness where it seems that all the possible pharmacological and therapeutic measures have failed.

TITLE: Hipotalamotomía en pacientes con agresividad refractaria: resultados funcionales.Introducción. La agresividad forma parte de las manifestaciones comportamentales asociadas a algunos trastornos mentales, es un síntoma de difícil manejo y, con frecuencia, es refractaria a las medidas farmacológicas. La cirugía de los trastornos del comportamiento surge como una alternativa terapéutica. Este procedimiento consiste en realizar intervenciones sobre distintas estructuras del sistema límbico, con el fin de corregir la alteración del circuito que estaría implicado en la producción de los síntomas. Objetivo. Describir los resultados clínicos de la hipotalamotomía posterior con gamma knife en el control de la agresividad en 20 pacientes refractarios al tratamiento, intervenidos en el Centro Médico Imbanaco entre 2013 y 2018. Pacientes y métodos. La gravedad de la agresividad se cuantificó mediante la escala de agresividad manifiesta (OAS) y la escala de impresión clínica global (CGI-SI), y su impacto funcional, a través de la escala de evaluación de la actividad global (EEAG). Resultados. El control de la agresividad se observó en todos los pacientes tratados con hipotalamotomía posterior con gamma knife, evidenciado por la disminución en las puntuaciones de la OAS y la CGI-SI y la mejoría en la EEAG. Conclusiones. La hipotalamotomía posterior muestra bajas complicaciones, seguridad en el procedimiento y buenos resultados, lo cual sugiere que podría ser una buena alternativa de tratamiento en los casos de agresividad refractaria donde las medidas farmacológicas y terapéuticas parecen agotarse.

Hydrological and hydrochemical behavior of a riparian zone in a high-order flatland stream.

Hydrological and hydrochemical processes occurring within riparian zones in temperate mid-latitudes flatland areas have significant implications for water management by controlling nutrient transfer between the watershed and the stream system. The riparian zone in a high-order flatland stream located within a 7063-km2 agricultural watershed in Argentina was investigated to study its hydrological connectivity to upland zones, interactions with the stream, and their implications for groundwater hydrochemistry. The analysis was based on 9-year-long time series of groundwater/stream water levels collected along a 220-m-long transect comprising six piezometers, a river stage sensor, and hydrochemical information from 37 groundwater/stream water sampling campaigns. Samples were analyzed for electrical conductivity (EC), Cl-, SO4+2, (Ca+2 + Mg+2), pH, and redox potential (ORP). Data were interpreted using descriptive statistics, statistical tests, groundwater flux calculations, and identification of hydrological patterns and associated hydrochemical responses. The system was hydrologically controlled by shallow groundwater. Three representative landscape hydrological patterns were identified: disconnected, incipient-weakly connected, and fully connected. Groundwater hydrochemistry was closely linked to hydrological connectivity, which played an important role in the mobilization and fluxes of solutes. Overall, groundwater EC, Cl-, SO4+2, and (Ca+2 + Mg+2) concentrations decreased from upland to lowland. For full connectivity, Cl- concentrations reduced 33%, while SO4+2 reduced 42%, demonstrating the system's buffering capacity. This investigation constitutes the first attempt to formulate the riparian zone functioning in this agricultural region and has contributed to the understanding on the complex interactions between hydrologic regimes of large flatland-high-order streams and shallow groundwater systems in fine-texture sediments.

Unusual presentations of Comamonas kerstersii infection.

The association of Comamonas kerstersii with peritonitis resulting from the presence of perforated appendix has previously been described by our research team. In the present study, we describe the isolation of this microorganism from two forms of unusual presentations of C. kerstersii infection not previously described in the literature: localized intra-abdominal infection (psoas abscess) and pelvic peritonitis.

Vector competence and innate immune responses to dengue virus infection in selected laboratory and field-collected Stegomyia aegypti (= Aedes aegypti).

Control of dengue virus (DenV) transmission, primarily based on strategies to reduce populations of the principle vector Stegomya aegypti (= Aedes aegypti) (Diptera: Culicidae), is difficult to sustain over time. Other potential strategies aim to manipulate characteristics such as vector competence (VC), the innate capacity of the vector to transmit the virus. Previous studies have identified genetic factors, including differential expression of apoptosis-related genes, associated with the refractory and susceptible phenotypes in selected strains of S. aegypti from Cali, Colombia. The present study was designed to evaluate the variability of VC in selected strains against different DenV serotypes and to determine whether field-collected mosquitoes respond similarly to selected laboratory strains in terms of enhanced or reduced expression of apoptosis-related genes. Vector competence differed between strains, but did not differ in response to different DenV serotypes. Differences in VC were observed among mosquitoes collected from different localities in Cali. The overexpression of the pro-apoptosis genes, caspase 16 and Aedronc, was conserved in field-collected refractory mosquitoes and the selected laboratory refractory strain. The results suggest that the apoptosis response is conserved among all refractory mosquitoes to inhibit the development of all DenV serotypes.

Effects of Glycyrrhizic acid on productive and immune parameters of broilers

Considering that glycyrrhizic acid (GRA) has been shown to have in-vitro and in-vivo antiviral activity against a wide range of viruses as well as immunostimulating activity, a trial to evaluate its effects on the performance and the immune response against Newcastle disease of broiler chickens was carried out. The study was performed with one-day-old Ross x Ross broiler chickens. GRA was added to the drinking water throughout the 49-d production cycle at a dose of 0.03%. Sample size of the trial was established in a pilot assay. Results showed that broiler chickens treated with GRA presented better weight gain, final body weight, feed conversion ratio, and lower mortality rate than the non-treated controls. In addition, GRA-treated birds presented higher antibody titers against Newcastle disease virus and more efficient cellular immune response, as demonstrated by the late-hypersensitivity response test. Blood lymphocyte and thrombocyte counts also increased in this group. The histopathological examination of the bursa, spleen, and thymus revealed that only the thymus of the GRA-treated group had a clearly defined increase in cortex thickness on day 49. The bursa showed a higher number of lymphoid lesions in CG on days 21 and 49 compared with the GRA group. These results suggest that GRA has growth promotion properties, which are possibly linked to immune-based effects.

Effects of Glycyrrhizic acid on productive and immune parameters of broilers

Considering that glycyrrhizic acid (GRA) has been shown to have in-vitro and in-vivo antiviral activity against a wide range of viruses as well as immunostimulating activity, a trial to evaluate its effects on the performance and the immune response against Newcastle disease of broiler chickens was carried out. The study was performed with one-day-old Ross x Ross broiler chickens. GRA was added to the drinking water throughout the 49-d production cycle at a dose of 0.03%. Sample size of the trial was established in a pilot assay. Results showed that broiler chickens treated with GRA presented better weight gain, final body weight, feed conversion ratio, and lower mortality rate than the non-treated controls. In addition, GRA-treated birds presented higher antibody titers against Newcastle disease virus and more efficient cellular immune response, as demonstrated by the late-hypersensitivity response test. Blood lymphocyte and thrombocyte counts also increased in this group. The histopathological examination of the bursa, spleen, and thymus revealed that only the thymus of the GRA-treated group had a clearly defined increase in cortex thickness on day 49. The bursa showed a higher number of lymphoid lesions in CG on days 21 and 49 compared with the GRA group. These results suggest that GRA has growth promotion properties, which are possibly linked to immune-based effects.(AU)

Water and chloride transport in a fine-textured soil in a feedlot pen.

Cattle feeding in feedlot pens produces large amounts of manure and animal urine. Manure solutions resulting from surface runoff are composed of numerous chemical constituents whose leaching causes salinization of the soil profile. There is a relatively large number of studies on preferential flow characterization and modeling in clayed soils. However, research on water flow and solute transport derived from cattle feeding operations in fine-textured soils under naturally occurring precipitation events is less frequent. A field monitoring and modeling investigation was conducted at two plots on a fine-textured soil near a feedlot pen in Argentina to assess the potential of solute leaching into the soil profile. Soil pressure head and chloride concentration of the soil solution were used in combination with HYDRUS-1D numerical model to simulate water flow and chloride transport resorting to the concept of mobile/immobile-MIM water for solute transport. Pressure head sensors located at different depths registered a rapid response to precipitation suggesting the occurrence of preferential flow-paths for infiltrating water. Cracks and small fissures were documented at the field site where the % silt and % clay combined is around 94%. Chloride content increased with depth for various soil pressure head conditions, although a dilution process was observed as precipitation increased. The MIM approach improved numerical results at one of the tested sites where the development of cracks and macropores is likely, obtaining a more dynamic response in comparison with the advection-dispersion equation.

La problemática del endosulfán: aspectos químicos, analíticos y ambientales / The roblem of enndosulfan: chemical, analytical and environmental issues

Introducción. Dado el carácter residual y el alto nivel de toxicidad del endosulfán, se ha incrementado la preocupación a nivel mundial por su impacto ambiental. Por eso la búsqueda de metodologías analíticas que permitan su detección y cuantificación es un tema de investigación vigente. Las propiedades del endosulfán y su patrón de degradación le confieren características que hacen muy compleja la problemática, al tiempo que el pesticida y sus metabolitos se expanden extensivamente por la atmósfera y contaminan tanto matrices lipofílicas como hidrofílicas. Objetivo. Llevar a cabo una revisión sobre las investigaciones más recientes acerca de la problemática del endosulfán, que incluye aspectos químicos, su problemática ambiental y técnicas inmunoquímicas para su análisis, tema en el que ha estado interesado nuestro grupo de investigación en la Universidad de Caldas. Método. El presente artículo de revisión analiza, cualitativamente, la literatura científica disponible en las bases de datos Science Direct, PubMed, Scielo y páginas Web oficiales, empleando como palabras de búsqueda: endosulfán, haptenos, análisis inmunoquímico del endosulfán, problemática ambiental del endosulfán, regulaciones internacionales sobre el endosulfán, normatividad vigente sobre el endosulfán, y métodos instrumentales de análisis. Resultados. Se obtuvo información pertinente relacionada con el objetivo propuesto, la cual se presenta en 3 secciones: aspectos químicos del endosulfán, problemática ambiental y técnicas inmoquímicas para su análisis. Conclusión. El endosulfán ha sido prohibido por los organismos internacionales. Sin embargo, el pesticida se continúa usando en algunos países y éste se difunde fácilmente hacia otras regiones, de tal manera que se ha convertido en un problema global. Hay investigaciones recientes sobre métodos de remediación química o biológica, pero los esfuerzos son modestos frente a la enorme problemática de este pesticida. En lo pertinente a análisis químicos de endosulfán, en los últimos 15 años se han investigado técnicas inmunoquímicas de análisis (basadas en haptenos), como alternativa a los métodos cromatográficos instrumentales.

Introduction. Due to the residual character and high level of toxicity of endosulfan, worldwide concern for its environmental impact has increased. Therefore, the search for analytical methodologies that allow its detection and quantification continues to be a topic of current research. Endosulfan properties and its degradation pattern confer it characteristics that make very complex the problematic while the pesticide and its metabolites are extensively spread throughout the atmosphere and contaminate both lipophilic and hydrophilic matrixes. Objective. To conduct a review on some recent research about the endosulfan problematic including chemical aspects, environmental issues and immunochemical techniques for its analysis, which is an area of current interest in this research group at Universidad de Caldas. Method. This review article analyzes qualitatively scientific literature from Science Direct, PubMed, Scielo databases and official Web pages using key words such as endosulfan, endosulfan immunochemical analysis, endosulfan environmental problematic, endosulfan international regulations, endosulfan current normativity and instrumental methods for the analysis. Results. Relevant information related to the proposed objective was found which is presented in 3 sections: chemical aspects of endosulfan, environmental issues, and immunochemical techniques for its analysis. Conclusions. Endosulfan has been banned by international organizations. However, the pesticide is still being used in some countries and is easily spread to other regions, so that the problem became a global concern. There is some recent research on biological or chemical remediation techniques, but efforts seem insufficient in comparison to the enormous impact of the pesticide. In regard to Endosulfan chemical analyses, during the past 15 years immunochemical hapten-based analysis techniques have been investigated as alternatives to the instrumental chromatographic methods.

First case of Streptococcus lutetiensis bacteremia involving a clindamycin-resistant isolate carrying the lnuB gene.

Here, we describe the first case of a Streptococcus lutetiensis isolate harboring the lnuB gene.

The epidemiology of life-threatening complications associated with reproductive process in public hospitals in Argentina.

OBJECTIVE: To analyse life-threatening obstetric complications that occurred in public hospitals in Argentina. DESIGN: Multicentre collaborative cross-sectional study. SETTING: Twenty-five hospitals included in the Perinatal Network of Buenos Aires Metropolitan Area. POPULATION: Women giving birth in participating hospitals during a 1-year period. METHODS: All cases of severe maternal morbidity (SMM) and maternal mortality (MM) during pregnancy (including miscarriage and induced abortion), labour and puerperium were included. Data were collected prospectively. MAIN OUTCOME MEASURES: Identification criteria, main causes and incidence of SMM; case-fatality rates, morbidity-mortality index and effective intervention's use rate. RESULTS: A total of 552 women with life-threatening conditions were identified: 518 with SMM, 34 with MM. Identification criteria for SMM were case-management (48.9%), organ dysfunction (15.2%) and mixed criteria (35.9%). Incidence of SMM was 0.8% (95% confidence interval [95% CI] 0.73-0.87%) and hospital maternal death ratio was 52.3 per 100 000 live births (95% CI 35.5-69.1). Main causes of MM were abortion complications and puerperal sepsis; main causes of SMM were postpartum haemorrhage and hypertension. Overall case-fatality rate was 6.2% (95% CI 4.4-8.6): the highest due to sepsis (14.8%) and abortion complications (13.3%). Morbidity-mortality index was 15:1 (95% CI 7.5-30.8). Use rate of known effective interventions to prevent or treat main causes of MM and SMM was 52.3% (95% CI 46.9-57.7). CONCLUSIONS: This study describes the importance of life-threatening obstetric complications that took place in public hospitals with comprehensive obstetric care and the low utilisation of known effective interventions that may decrease rates of SMM and MM. It also provides arguments that justify the need to develop a surveillance system for SMM.

Bases para establecer un sistema de vigilancia activa y respuesta rápida para el manejo de la morbilidad materna severa / Basis for establishing an active surveillance and rapid response system for the management of severe maternal morbidity

INTRODUCCIÓN La razón de mortalidad materna (RMM) se ha utilizado como indicador de salud sin considerar los eventos precedentes. La morbilidad materna severa (MMS) incluye a mujeres con morbilidad asociada a un embarazo, que amenaza sus vidas pero que finalmente permite la sobrevida. OBJETIVOS Investigar la situación de la mortalidad materna (MM) y la MMS en Misiones, Jujuy y La Rioja. Establecer bases para un sistema de vigilancia y manejo de casos. MÉTODOS Se realizó un estudio multicéntrico de prevalencia con un componente de implementación. Mujeres embarazadas, tratadas en el subsector público entre el 1 de octubre de 2013 y el 31 de marzo de 2014, fueron tamizadas para detectar condiciones potencialmente fatales (CPF) y notificar MMS y MM. RESULTADOS Se analizaron 9 921 nacimientos. Ingresaron 294 mujeres, y hubo 219 (74,5%) casos de CPF, 67 (22,8%) de MMS y 8 (2,7%) de MM. Criterios de identificación por tamizaje: clínicos 78,1% de CPF, basados en enfermedad 94% de MMS, y 100% de MM presentó algún criterio clínico. Las principales causas de MMS fueron hipertensión (35,8%), hemorragias (29,9%) y complicaciones de abortos (13,4%). La incidencia global de CPF fue 2,21%, la de MMS 0,68% y la de MM 0,08%. El índice de morbimortalidad global fue de 8,4 (4,0-7,4), la tasa de letalidad global fue del 10,7%, y el uso global de intervenciones beneficiosas para el manejo de MMS fue del 54,8%. DISCUSIÓN El estudio permitió conocer la MM y la MMS en las tres provincias y sentar las bases para implementar un sistema de vigilancia activa y respuesta rápida para el manejo de la MMS, consistente con el Plan Operativo Nacional.

Host preference of the arbovirus vector Culex erraticus (Diptera: Culicidae) at Sonso Lake, Cauca Valley Department, Colombia.

Culex erraticus (Dyar & Knab) is a competent vector of Eastern equine encephalitis virus and subtype IC Venezuelan equine encephalitis virus, and both St. Louis encephalitis virus and West Nile virus have been isolated from field-collected specimens. Previous bloodmeal analysis studies have shown this species to be a generalist, feeding on a variety of mammals, birds, reptiles, and amphibians. This behavior can bridge arboviral transmission across different vertebrate groups. Our study examined the host preference of Cx. erraticus at Sonso Lake in Colombia. From July to August 2008, blood-engorged mosquitoes were collected from resting boxes, while vertebrate abundance was determined to calculate host preference. Based on mitochondrial DNA analysis of bloodmeals, birds were the predominant hosts (57.6%), followed by mammals (30.8%), and reptiles (6.7%); 9.5% of the bloodmeals were mixed. The most commonly fed upon species were: limpkin, black-crowned night-heron, striated heron, human, and capybara. Forage ratios showed the least bittern, limpkin, Cocoi heron, striated heron, capybara, and black-crowned night heron were preferred hosts across all vertebrates. Of the available avifauna, the least bittern, limpkin, striated heron, Cocoi heron, and black-crowned night heron were preferred, whereas the bare faced ibis, great egret, snowy egret, and cattle egret were under-used. This study shows that while Cx. erraticus is an opportunistic feeder, using diverse vertebrate hosts in the environment, certain avian species are targeted preferentially for bloodmeals.

Environmental factors associated with American cutaneous leishmaniasis in a new Andean focus in Colombia.

OBJECTIVE: To evaluate the environmental and ecological factors associated with Leishmania transmission and vector abundance in Chaparral, Tolima-Colombia. METHODS: First, we compared the ecological characteristics, abundance of phlebotomies and potential reservoir hosts in the peridomestic environment (100 m radius) of randomly selected houses, between two townships with high and low cutaneous leishmaniasis incidence. Second, we examined peridomestic correlates of phlebotomine abundance in all 43 houses in the higher risk township. RESULTS: The high transmission township had higher coverage of forest (23%vs. 8.4%) and shade coffee (30.7%vs. 11%), and less coffee monoculture (16.8%vs. 26.2%) and pasture (6.3%vs. 12.3%), compared to the low transmission township. Lutzomyia were more abundant in the high transmission township 2.5 vs. 0.2/trap/night. Lutzomyia longiflocosa was the most common species in both townships: 1021/1450 (70%) and 39/80 (49%). Numbers of potential wild mammal reservoirs were small, although four species were found to be infected with Leishmania (Viannia) spp. In the high transmission township, the overall peridomiciliary capture rate of L. longiflocosa was 1.5/trap/night, and the abundance was higher in houses located nearer to forest (ρ = -0.30, P = 0.05). CONCLUSION: The findings are consistent with a domestic transmission cycle with the phlebotomies dependent on dense vegetation near the house.

Clinical description and evolution of renal transplant pediatric patients treated with alemtuzumab.

BACKGROUND: Renal transplantation is the most effective treatment for children with end-stage renal disease. Recent work suggests that induction with alemtuzumab in the pediatric population permits the use of lower doses of maintenance immunosuppressive therapy. In addition, it has a low cost compared with other induction therapies. OBJECTIVE: To conduct a clinical description of pediatric renal transplant patients comparing induction protocols to evaluate graft and patient survival, infections complications, and lymphoproliferative diseases. MATERIALS AND METHODS: This descriptive and retrospective study, of evaluated pediatric renal transplant patients between 2006 and 2010. RESULTS: The agents for induction therapy were: alemtuzumab (61.5%), daclizumab (19.25%), and thymoglobulin (19.25%). Graft survival was better among the alemtuzumab group (87.5%) compared with the other two induction therapies (80%). The frequency of acute rejection episodes during the first year posttransplantation as well as chronic rejection was lower among the alemtuzumab group. Cytomegalovirus infection was noted in 30% of patients with greater frequency among those induced with alemtuzumab. CONCLUSION: Induction therapy with alemtuzumab was safe in a pediatric population not predisposing to a greater risk of acute or chronic rejection. Except for a greater incidence of Cytomegalovirus, there was no difference in other complications.

Induction therapies in kidney transplantation: the experience of Hospital Pablo Tobon Uribe, Medellín, Colombia 2005-2010.

BACKGROUND: Induction therapies in kidney transplantation have led to prescriptions of lower doses of maintenance immunosuppression and fewer acute rejection episodes. We sought to assess the use of an affordable monoclonal antibody in terms of the incidences of rejection episodes as well as graft and patient survivals and cytomegalovirus (CMV) and opportunistic infections among our kidney transplant recipients between August 2005 and December 2010. Data were obtained for patients who had more than 20 months' follow-up. MATERIALS AND METHODS: We retrospectively analyzed data from kidney recipients between August 2005 and December 2010, using descriptive statistics and Kaplan-Meier survival analysis. We performed a multivariate analysis with logistic regression for the dependent variables of rejection episodes and death. RESULTS: Among 425 transplant patients graft survival was 89.2% and patient survival was 94.1% after 76.2% of patients received alemtuzumab, 10.7% daclizumab, 3.6% basiliximab, 2.4% thymoglobulin, and 7%, no induction therapy. Rejection incidence in general in the first year was 10.8% and CMV incidence 10%. There was an increased risk of rejection among subjects without any us with alemtuzumab induction therapy. CONCLUSION: Induction therapies show an important reduction in kidney transplant rejection incidence during the first year, allowing low doses of maintenance immunosuppressants, thereby diminishing long-term adverse effects. Alemtuzumab seemed to be a safe alternative with similar results to those obtained with standard immunosuppression.

An empirical model for treatment of arsenic contaminated underground water by electrocoagulation process employing a bipolar cell configuration with continuous flow.

Arsenic (As) was removed electrochemically from underground water (GW) by electrocoagulation (EC) process employing a bipolar cell configuration with continuous flow using iron electrodes. A kinetic model derived from the Lagergren equation was applied to specify the kinetics of the arsenic removal reaction. Elucidation of the effect of the liquid flow rate on the treatment time and on the simulation results of the model was achieved. The results showed that treatment times decreased from 10.50 min to 0.75 min as the flow rate decreased from 3.500 to 0.875 L min(-1) and the current density varied from 15 to 45 A m(-2) respectively. The used sorption kinetic model successfully describes the arsenic removal by this process. The coefficients of determination were found to be very high in all cases (R(2)>0.99) indicating a good fit of the experimental data to Lagergren model.

Energy and electrode consumption analysis of electrocoagulation for the removal of arsenic from underground water.

A systematic study of the effect of design and operation conditions of an electrochemical reactor on the treatment time for arsenic (As) electro-removal from underground water (GW) was carried out to analyse the energy and electrode consumption. The effects of four factors--current density, interelectrode distance, electrode area-volume ratio, and liquid motion driving mode--were evaluated. The response variables were the energy and the electrode consumption and the treatment time to reduce the GW residual As concentration to 10 microg L(-1), which is the maximum contaminant level (MCL) established by the World Health Organization (WHO) in drinking water. The results obtained in this study showed that the factor that had the greatest effect on most of the response variables was the liquid motion driving mode. The best residence time was 20s, which favoured low energy consumption (58.78 Wh m(-3)) and low electrode material loss (9.59 g m(-3)).

Nanoscale Visualization of Elastic Inhomogeneities at TiN Coatings Using Ultrasonic Force Microscopy.

Ultrasonic force microscopy has been applied to the characterization of titanium nitride coatings deposited by physical vapor deposition dc magnetron sputtering on stainless steel substrates. The titanium nitride layers exhibit a rich variety of elastic contrast in the ultrasonic force microscopy images. Nanoscale inhomogeneities in stiffness on the titanium nitride films have been attributed to softer substoichiometric titanium nitride species and/or trapped subsurface gas. The results show that increasing the sputtering power at the Ti cathode increases the elastic homogeneity of the titanium nitride layers on the nanometer scale. Ultrasonic force microscopy elastic mapping on titanium nitride layers demonstrates the capability of the technique to provide information of high value for the engineering of improved coatings.