Nitrogen flow analysis in Spain: Perspectives to increase sustainability.

Nitrogen (N) is a macronutrient that, together with P and K, is vital for improving agricultural yields, but its excessive use in crop fertilisation and presence in treated wastewater and sludge are generating emissions both into the atmosphere and into natural water bodies, which leads to eutrophication events. The Haber-Bosch process is energy-intensive and it is the main chemical route to produce reactive nitrogen for the production of fertilisers. Furthermore, there is a strong dependence on imports of reactive nitrogen in Spain and Europe. For these reasons, it is necessary to propose sustainable alternatives that allow solving environmental and supply problems, in addition to proposing efficient management schemes that fit into the circular economy approach. In this context, a nitrogen flow analysis (NFA) was carried out for Spain with the year 2016 as reference. To assess some interactions and flows of N, specific sub-models were also considered for the agriculture and waste management systems. For the food and non-food flow systems, country-specific data were considered. The sectors covered were crop production (CP), animal production (AP), food processing (FP), non-food production (NF) and human consumption (HC). The results reveal a total annual import of 2142 kt N/y, of which 43 % accumulated in stocks of soils and water bodies (913 kt N/y). The largest proportion of losses was associated with emissions from agriculture (724 kt N/y to water bodies and 132 kt N/y accumulated in soils), followed by industry emissions to the atmosphere (122 kt N/y). Wastewater treatment plants (WWTPs) received around 67 kt N/y, of which 26 % was removed as biosolids and 20 % of these biosolids were recovered to be used for fertilising applications. The 49 kt N/y discharged in the final treated effluent represented 79 % of the total loss of reactive nitrogen to water bodies. In addition, an analysis of N-use efficiency and the actions required for its improvement in Spain, as well as the impact of the current diet on the N cycle, was carried out.

Metamagnetic fluctuation characteristics near dynamic phase transitions.

We experimentally explore the magnetization dynamics of thin ferromagnetic Co films with uniaxial in-plane anisotropy near the dynamic phase transition (DPT) and, in particular, we study the temporal characteristics of anomalous metamagnetic fluctuations that occur in its vicinity, and for which no thermodynamic equivalent exists. For this purpose, we measure the real-time evolution of magnetization trajectories in the relevant dynamic phase space, conduct a Fourier analysis of these experimental results and compare it to a model, in which the fluctuating metamagnetic behavior occurs in a purely random manner, following individual state probability distributions. We find excellent quantitative agreement in between our experimental results and the random state model, clearly indicating that multiperiod time-correlations of magnetic states are not relevant in our DPT system, not even for the occurrence of the anomalous metamagnetic fluctuations that are nonetheless associated with nonperiodic magnetic state evolutions.

Techno-economic assessment of decentralized polishing schemes for municipal water reclamation and reuse in the industrial sector in costal semiarid regions: The case of Barcelona (Spain).

This study demonstrates the techno-economic reliability of an innovative fit-for-use treatment train to boost municipal reclaimed water reuse fore industrial uses in the Barcelona Metropolitan Area (BMA). The relatively high conductivity (2090 µS/cm) and hardness (454 mg/L) of reclaimed water in the BMA (e.g. Water Reclamation Plant (WRP) of El Baix Llobregat, Barcelona, Spain), together with the restrictive water quality demands in industrial uses, claims for the implementation of advanced reclamation schemes based on desalination technologies such as reverse osmosis (RO). The study assesses the benefits of two potential pre-treatments of the RO stage: (i) ultrafiltration (UF) or (ii) an innovative high-performance nano-structured polymeric adsorbent (CNM); in which a permeability decline of 5% was observed when CNM was used as a pre-treatment, while a stable permeability of RO was found when was fed by the UF effluent. On the other hand, generic cost curves have been calculated for the technologies evaluated and were applied to estimate capital and operational expenditures (CAPEX and OPEX) for the scale-up in three different industrial sites (e.g., chemical, waste management and electro-coating industries). The economic assessment indicates that the use of municipal reclaimed water is economically competitive in front of the use of tap water in the BMA, providing savings between 0.13 and 0.52 €/m3 for the waste management industry and between 0.49 and 0.98 €/m3 for the electrocoating industry. On the other hand, the use of groundwater in one of the industrial sites and its relatively low cost implied that, although it is necessary a RO, the current cost of water is significantly lower.

Recovery of rare earth elements from acidic mine waters: An unknown secondary resource.

Acidic mine Drainage (AMD) is still considered one of the greatest mining sustainability challenges due to the large volumes of wastes generated and the high associated treatment cost. New regulation initiatives on sustainable development, circular economy and the need for strategic elements as Rare Earth Elements (REE) may overcome the traditional research initiatives directed to developing low cost treatment options and to develop research initiatives to identify the potential benefit of considering such AMD as a potential secondary resource. As an example, this study develops the integration of a three-stage process where REE are selectively separated from base metals (e.g. Fe, Al, Mn, Ca, Mg, Cd, Pb) and then concentrate to produce a rich REE by-product recovered as REE-phosphates. Selective separation of Fe (>99%) was achieved by total oxidation to Fe(III) and subsequent precipitation as schwertmannite at pH 3,6 ± 0.2. REE were then extracted from AMD using a sulfonic ion-exchange resin to produce concentrated REE sulfuric solutions up to 0.25 gREE/L. In a final stage selective separation of REE from Al(III), Ca(II) and Mg(II) and transitions elements (Cu, Zn, Ni) was achieved by precipitation with phosphate solutions under optimized pH control and total phosphate concentration. XRD analysis identified low-crystalline minerals. By using a thermal treatment the presence of PrPO4(s) and Cheralite (CePO4(s)) where Ce is substituted by La and Ca and Xenotime (YPO4(s)) were found as main minerals AlPO4(s) Ca,MgYPO4(s) were also identified.

Integration of membrane distillation as volume reduction technology for in-land desalination brines management: Pre-treatments and scaling limitations.

Management of in-land reverse osmosis (RO) desalination brines generated from surface brackish waters is a current challenge. Among the different near-Zero and Zero Liquid Discharge (ZLD) alternatives, Membrane Distillation (MD), in which the transport of water is thermally driven, appears as an attractive technology if a residual heat source is available. The aim of this study was to identify the limits of Direct Contact MD (DCMD) pre-treatments such as acidification and aeration, or the combination of both to quantify the scaling reduction potential when treating a RO brine from surface brackish water. Experimental data were used to evaluate the effectiveness of DCMD to achieve the highest concentration factors, depending on the chosen pre-treatment. Additionally, an economic analysis of the operational cost, taking as case study a site where the current management of the brine is the discharge to the sea, was also carried out. Results showed that pre-treatments enhanced MD performance by increasing the concentration factor achieved and highest volume reductions (about 3 times) were reached with the combination of acidification and aeration pre-treatments. Both processes reduced the precipitation potential of CaCO3(s) by reducing the total inorganic carbon (>90%); however, CaSO4·2H2O(s) precipitated. Results also indicated that even if a waste heat source is available, brine disposal into the sea is the cheapest option, while ZLD alternatives were not attractive in the current regulatory framework since their cost was higher than the discharge to the sea. Other options related to the Minimal Liquid Discharge may be more economically attractive.

Valorisation options for Zn and Cu recovery from metal influenced acid mine waters through selective precipitation and ion-exchange processes: promotion of on-site/off-site management options.

Acid mine waters (AMWs), generated in the processing of polymetallic sulphides, contain copper and zinc as the main valuable transition metal ions, which are typically removed by liming, due to their great environmental impact. In this context, this work proposes the integration of selective precipitation (SP) and ion-exchange (IX) processes for the separation and recovery of both valuable metals to encourage on-site and off-site management options promoting valorisation routes. Thus, the main objectives of this work were (i) the selective removal of Fe(III) and Al(III), using NaOH under pH control (pH < 5) to avoid the precipitation of Cu(II) and Zn(II) and (ii) the evaluation of a solvent-impregnated resin (Lewatit VP OC 1026, named VP1026) and a cation IX resin (Lewatit TP 207, named TP207) for the sequential extraction of both metal ions from AMW (batch and column experiments). Results indicated that the metallic pollution load was mostly removed during the SP process of Fe(III) (>99%) and Al(III) (>90%) as hydroxylsulphates (e.g., schwertmannite and basaluminite). The metal extraction profiles were determined for both metals from pH 1 to pH 5 by batch experiments, and indicated that the best extraction of Zn(II) was obtained using VP1026, being higher than 96% (pH = 2.6-2.8), whereas TP207 extraction performance was optimal for Cu(II) extraction (>99%) at pH = 3-4. Moreover, in dynamic experiments using a fixed-bed configuration, it was possible to separate and concentrate Zn(II) (concentration factor = 10) and Cu(II) (concentration factor = 40) using VP1026 and TP207, respectively. Overall, the integration of SP and IX processes showed a great potential in the separation and recovery of valuable metals from mine waters to promote a circular economy, based on the management proposal for non-ferrous metallurgical industries. The recovered Zn-rich and Cu-rich sulphuric concentrated streams were theoretically evaluated for further on-site or off-site re-use treatments (e.g., electrowinning, precipitation, crystallization).

Integration of liquid-liquid membrane contactors and electrodialysis for ammonium recovery and concentration as a liquid fertilizer.

The accumulation of ammonia in water bodies can cause eutrophication and reduce water quality. Furthermore, 80% of the ammonia in the world is consumed as fertilizer, which makes it a resource that can be recovered under the circular economy concept. Then, ammonia from wastewater can be valorised for agricultural applications. Liquid-liquid membrane contactors (LLMCs) have been postulated as a novel and eco-friendly technology for ammonia recovery, because they can convert dissolved ammonia into ammonium salts by an acid stripping solution. The concentration of the ammonium salt produced is limited by the co-transport of water in LLMC. Further concentration by electrodialysis (ED) is presented as a solution to overcome this problem. In this work, ammonia streams with different initial ammonia concentrations (1.7-4.0 g/L) were treated by LLMCs to produce liquid ammonium salt fertilizers (as NH4NO3 and NH4H2PO4). Then, these ammonium solutions were concentrated by ED in order to achieve the nitrogen content required for direct application in agriculture for fertigation. After the LLMC process, the fertilizer obtained was composed of approximately 5.1% or 10.1% (w/w) nitrogen, depending on the initial ammonia concentration. After that, it was possible to concentrate these ammonium salts by a factor of 1.6 ± 0.3 using ED with an optimal energy consumption of 0.21 ± 0.08 kWh/kg ammonium salt and 93.1 ± 4.2% of faradaic yield. This gave a liquid fertilizer composed of 15.6% (w/w) nitrogen as NH4NO3. Overall, it was possible to integrate two innovative membrane technologies for the valorisation and concentration of nutrients from ammonia wastewater streams.

Techno-economic evaluation and comparison of PAC-MBR and ozonation-UV revamping for organic micro-pollutants removal from urban reclaimed wastewater.

The presence of sewage-borne Organic Micro-Pollutants (OMP) in Wastewater Treatment Plants (WWTP) effluents represents an increasing concern when water is reclaimed for irrigation or even indirect potable reuse. During eighteen months, an innovative hybrid water reclamation scheme based on a Membrane Biological Reactor (MBR) enhanced with Powder Activated Carbon (PAC) was operated at pilot-scale (70 m3/d) in order to compare it with state-of-the art Wastewater Reclamation System (WWRS) also revamped with a final step of ozonation-UV. Removal of persistent OMP, water quality and treatment costs were evaluated and compared for the different treatment schemes. OMP removal efficiency results for the different schemes concluded that established technologies, such as physico-chemical and filtration systems as well as MBR, do not remove significantly (>15%) the most recalcitrant compounds. The upgrading of these two systems through the addition of ozonation-UV step and PAC dosing allowed improving average recalcitrant OMP removal to 85 ±â€¯2 and 75 ±â€¯5%, respectively. In term of costs, PAC-MBR represents an increase of 37% of costs regarding conventional systems but presents improvements of 50% reduction in space and water quality. On the other hand, ozonation requires up to a 15% increase of foot-print; nevertheless, represents lower costs and lower carbon footprint. Ozonation-UV seems to be the best option for upgrading existing facilities, while PAC-MBR should be considered when space represents a critical limitation and produced water is reused for high water quality purposes.

El método de clasificación de mortinatos "Condición Obstétrica Relevante de la Muerte Fetal" (CORM) reduce la frecuencia de muerte fetal de causa inexplicable / The stillbirth classification method "Relevant Obstetric Condition of Stillbirth" (CORM) reduces the frequency of unexplained fetal death

RESUMEN Introducción: La muerte fetal (MF) es el principal contribuyente de la mortalidad perinatal. Objetivo: Analizar la eficiencia del método de clasificación de mortinatos, condición obstétrica relevante de la MF (CORM). Métodos: Estudio cohorte retrospectivo, de las MF ocurridas en la Maternidad del Hospital San Borja Arriarán durante 10 años. Los datos provienen de los informes de las auditorías de mortinatos. Se aplicó el método de clasificación CORM, que usa la biopsia placentaria, los datos clínicos y de laboratorio analizados por un obstetra y un patólogo. Resultados: Ocurrieron 56.130 nacimientos y 479 MFs. Tasa de MF, 8.5 por 1000 nacimientos. Se identificaron el 93.5% de las condiciones obstétricas de MF y 6.5% fueron inexplicables. Las más frecuentes fueron: infección bacteriana ascendente (IBA) 24.9%, anomalía congénita 18.0%, y patología placentaria 14.0%. La restricción del crecimiento fetal intrauterino (RCIU) se presentó en el 49.7% de los mortinatos, la mayoría 93.7%, fue secundaria a condición obstétrica primaria. La asfixia durante el parto fue el 0.8% de los mortinatos y se presentó en embarazos de término. El parto prematuro (PP) representó el 80% de los casos de MF. La condición más frecuente asociada con PP fue IBA (38.5% y 38.2% de las MF menores de 30 semanas y menores de 1000 gramos respectivamente). Conclusiones: El método clasificación de mortinatos CORM, es más eficiente que los métodos convencionales en detectar la causa de MF porque identifica la mayoría de las condiciones obstétricas responsables de la MF. Es reproducible, requiere estudio histopatológico de la placenta y no de autopsia fetal. Permite elaborar guías de prevención por causa.

SUMMARY Introduction: Stillbirth is the main contributor to perinatal mortality. Aim: To analyze the efficiency of the method for classification of fetal death (FD), "obstetric condition relevant to the death (OCRD). Methods: Retrospective cohort study of the FD that occurred in the Maternity Hospital of San Borja Arriarán for ten years. The data comes from the reports of the stillborn audits. We applied the classification method OCRD, which uses placental biopsy, clinical and laboratory data analyzed by a single obstetrician and a single pathologist. Results: 56,130 births and 479 FD occurred. FD rate, 8.5 per 1000 births. We identified 93.5% of the obstetric conditions of FD and 6.5% were unexplained. The most frequent were: ascending bacterial infection (ABI) 24.9%, congenital anomaly 18.0%, and placental pathology 14.0%. The intrauterine fetal growth restriction (IUGR) was present in 49.7% of the stillbirths, the majority 93.7%, was secondary to primary obstetric condition. Asphyxia during delivery was 0.8% of the stillbirths and occurred in term pregnancies. Preterm birth (PB) represented 80% of FD cases. The most frequent condition associated with PB was ABI (38.5% and 38.2% of the FD less than 30 weeks and less than 1000 grams respectively). Conclusions: The OCRD stillbirth classification method is more efficient than conventional methods in detecting the cause of MF because it identifies most of the obstetric conditions responsible for FD. It is reproducible, requires histopathological study of the placenta and not fetal autopsy. It allows developing guidelines of prevention for cause.

Simultaneous ammonium and phosphate recovery and stabilization from urban sewage sludge anaerobic digestates using reactive sorbents.

The use of low-cost inorganic sorbents as a new sustainable strategy to enhance the valorization of nutrients (N-P-K), from the urban water cycle (e.g., side streams from sewage sludge anaerobic digestion), in agriculture applications is presented. The simultaneous recovery and stabilization of ammonium and phosphate by using a mixture of two reactive sorbents (Na and K zeolites and magnesium oxide) was evaluated. The nutrients stabilization process, favoured at alkaline pH values, is carried out by a) the precipitation of phosphate ions with magnesium and/or ammonium ions and b) the sorption of ammonium by Na- and K-zeolites. MgO(s) promoted the stabilization of phosphate as bobierrite (Mg3(PO4)2(s)) or struvite (MgNH4PO4(s)) depending on the applied dose. Doses with the stoichiometric molar ratio of Mg/P promote the formation of bobierrite, while molar ratios higher than 3 favour the formation of struvite. Na zeolites (NaP1-NA, NaP1-IQE) demonstrated efficiency on ammonium stabilization between 60±2 (for 15gZ/L) to 90±3% (for 50gZ/L). The ammonium recovery efficiency is limited by the zeolite sorption capacity. If the target of the fertilizing criteria should include K, then the use of a K-zeolite (e.g., 5AH-IQE) provides a good solution. The optimum pH for the precipitation of struvite and bobierrite is 9.5 and the optimum pH for ammonium removal is between 4 and 8.5. N is present in higher concentrations (up 0.7-1gNH4+/L) when pH is ranged between 8.2 and 8.6. The ammonium recovery ratios were better than those previously reported using only magnesium oxide or even a more expensive reagent as newberrite (MgHPO4(s)). The recovery mechanisms described generate low-solubility stabilized nutrients forms that potentially can be applied as slow-release fertilizers in agriculture. Thus, the use in agriculture of blends of digested sludge with low-solubility stabilized nutrients forms will improve soils quality properties in terms of organic matter and nutrients availability.

Recovery of ammonia from domestic wastewater effluents as liquid fertilizers by integration of natural zeolites and hollow fibre membrane contactors.

The integration of up-concentration processes to increase the efficiency of primary sedimentation, as a solution to achieve energy neutral wastewater treatment plants, requires further post-treatment due to the missing ammonium removal stage. This study evaluated the use of zeolites as a post-treatment step, an alternative to the biological removal process. A natural granular clinoptilolite zeolite was evaluated as a sorbent media to remove low levels (up to 100mg-N/L) of ammonium from treated wastewater using batch and fixed bed columns. After being activated to the Na-form (Z-Na), the granular zeolite shown an ammonium exchange capacity of 29±0.8mgN-NH4+/g in single ammonium solutions and 23±0.8mgN-NH4+/g in treated wastewater simulating up-concentration effluent at pH=8. The equilibrium removal data were well described by the Langmuir isotherm. The ammonium adsorption into zeolites is a very fast process when compared with polymeric materials (zeolite particle diffusion coefficient around 3×10-12m2/s). Column experiments with solutions containing 100mgN-NH4+/L provide effective sorption and elution rates with concentration factors between 20 and 30 in consecutive operation cycles. The loaded zeolite was regenerated using 2g NaOH/L solution and the rich ammonium/ammonia concentrates 2-3g/L in NaOH were used in a liquid-liquid membrane contactor system in a closed-loop configuration with nitric and phosphoric acid as stripping solutions. The ammonia recovery ratio exceeded 98%. Ammonia nitrate and di-ammonium phosphate concentrated solutions reached up to 2-5% wt. of N.

Consumo de alcohol en el adulto mayor chileno que viaja / Alcohol consumption among traveling Chilean older people

Background: Problems associated with alcohol consumption are prevalent in Chile, but little is known about the situation in the elderly. Aim: To perform a screening to detect alcohol-related problems and risks in the Chilean older people who travel. Material and Methods: The Alcohol Use Disorders Identification Test (AUDIT) questionnaire was answered by 1,076 travelers aged 60 to 93 years (66% females), who participated in trips organized by the Chilean National Tourism Service (SERNATUR). Results: Seventy six percent of respondents acknowledged to have ingested an alcoholic drink during the last month. The average AUDIT score was of 2.2 ± 2.6. Only 3.7% of the sample had a score equal or higher than eight, considered as risky use. Within this last group, 60% had symptoms of alcohol dependence. A higher alcohol consumption was associated with male gender (p < 0.01), being younger than 75 years of age (p < 0.01), having a medium-low economic income (p < 0.01) and having a higher education level (p = 0.03). There was no significant association with the respondents´ occupation. Conclusions: In this sample of Chilean traveling older people, there was a high prevalence of alcohol consumption, and nearly 4% of respondents had alcohol related problems.

Infecciones osteoarticulares no vertebrales por Candida spp. en un hospital de alta complejidad en Medellín, Colombia / Non vertebral osteoarticular infections by Candida spp. in a hospital of high complexity in Medellín, Colombia / Infecções osteoarticulares não vertebrais por Cândida spp. num hospital de alta complexidade em Medellín, Colômbia

Objetivo: describir las características clínicas y demográficas de pacientes con osteomielitis por Candida spp. en el Hospital Pablo Tobón Uribe de Medellín. Metodología: observacional descriptiva. Resultados: se encontraron 30 pacientes con osteomielitis por Candida spp. El 70% está conformado por hombres, con una media de edad de 49.9 años. El 46% tenía como antecedente algún tipo de inmunosupresión. El 60% tenía osteomielitis por Candida spp. como único aislamiento y 40%, osteomielitis bacteriana concomitante. Un paciente tuvo candidemia. El 46% tenía previamente una intervención quirúrgica y el 26% algún tipo de material de osteosíntesis. 26 pacientes (86%) recibieron antibióticos previamente, y son los carbapenémicos, piperacilina, tazobactam y vancomicina los más utilizados. El hueso largo fue el segmento óseo más afectado: 33%. Candida no albicans estuvo en el 63% y Candida spp. en un 3.3%. De Candida no albicans la más frecuente fue Candida. parapsilosis en 57%. El 97% de los aislamientos fue sensible a fluconazol y voriconazol. El 46% completó tratamiento. De un 43% no se obtuvo el dato de seguimiento y el 6.6% no completó el tratamiento. Conclusiones: la osteomielitis por Candida es una entidad que está en aumento y crea la necesidad de realizar estudios analíticos para explorar los factores de riesgo relacionados. Además, se confirma el aumento de los aislamientos de Candida no albicans que se describe en la literatura y se encontró sólo un caso con sensibilidad intermedia a fluconazol.

Objective: To describe the clinical and demographical characteristics of patients with osteomyelitis due to Candida spp. in Hospital Pablo Tobón Uribe in Medellín. Methodology: Observational, descriptive study. Results: Thirty patients were found to have osteomyelitis due to Candida spp. Of these, 70% were male, with a mean age of 49.9 years. 46% had a history of some type of immunosuppression; 60% had osteomyelitis due to Candida spp. where it was the only microorganism isolated and 40% had concomitant bacterial osteomyelitis. One patient had candidemia. 46% had previously undergone surgery and 26% had had some type of osteosynthesis material. Twenty-six patients (86%) had previously received antibiotics, where carbapenems, piperacillin, tazobactam, and vancomycin were the most frequently used. The long bones were the most affected osseous segments (33%). Non-albicans Candida was 63% and Candida spp. 3.3%. The most frequent of non-albicans Candida was Candida parapsilosis in 57%. 97% of isolations were sensitive to fluconazole and voriconazole. 46% finished treatment. Follow-up data were not collected from 43%, while 6.6% did not finish treatment. Conclusions: As osteomyelitis due to Candida is increasing, analytic studies are warranted to explore associated risk factors. There was also an increase in non-albicans Candida compared to that which has been described in the literature, and only one case was found to have intermediate sensitivity to fluconazole.

Objetivo: descrever as características clínicas e demográficas de pacientes com osteomelite por Cândida spp. no Hospital Pablo Tobón Uribe de Medellín. Metodologia: observacional descritiva. Resultados: se encontraram 30 pacientes com osteomelite por Cândida spp. 70% está conformado por homens, com uma idade meia de 49.9 anos. 46% tinha como antecedente algum tipo de imunossupressão. 60% tinha osteomelite por Cândida spp. como único isolamento e 40%, osteomelite bacteriana concomitante. Um paciente teve candidemia. 46% tinha previamente uma intervenção cirúrgica e 26% algum tipo de material de osteosíntese. 26 pacientes (86%) receberam antibióticos previamente, e são os carbapenémicos, piperacilina, tazobactam e vancomicina os mais utilizados. O osso longo foi o segmento ósseo mais afetado: 33%. Cândida não albicans esteve em 63% e Cândida spp. em 3.3%. De Cândida não albicans a más frequente foi Cândida parapsilosis em 57%. 97% dos isolamentos foi sensível a fluconazol e voriconazol. 46% completou tratamento. De um 43% não se obteve dato de seguimento e 6.6% não completou o tratamento. Conclusões: a osteomielitis por Cândida é uma entidade que está em aumento e cria a necessidade de realizar estudos analíticos para explorar os fatores de risco relacionados. Ademais, se confirma o aumento dos isolamentos de Cândida não albicans que se descreve na literatura e se encontrou só um caso com sensibilidade intermedia a fluconazol.

Simultaneous and automated monitoring of the multimetal biosorption processes by potentiometric sensor array and artificial neural network.

In this communication, a new methodology for the simultaneous and automated monitoring of biosorption processes of multimetal mixtures of polluting heavy metals on vegetable wastes based on flow-injection potentiometry (FIP) and electronic tongue detection (ET) is presented. A fixed-bed column filled with grape stalks from wine industry wastes is used as the biosorption setup to remove the metal mixtures from the influent solution. The monitoring system consists in a computer controlled-FIP prototype with the ET based on an array of 9 flow-through ion-selective electrodes and electrodes with generic response to divalent ions placed in series, plus an artificial neural network response model. The cross-response to Cu(2+), Cd(2+), Zn(2+), Pb(2+) and Ca(2+) (as target ions) is used, and only when dynamic treatment of the kinetic components of the transient signal is incorporated, a correct operation of the system is achieved. For this purpose, the FIA peaks are transformed via use of Fourier treatment, and selected coefficients are used to feed an artificial neural network response model. Real-time monitoring of different binary (Cu(2+)/ Pb(2+)), (Cu(2+)/ Zn(2+)) and ternary mixtures (Cu(2+)/ Pb(2+)/ Zn(2+)), (Cu(2+)/ Zn(2+)/ Cd(2+)), simultaneous to the release of Ca(2+) in the effluent solution, are achieved satisfactorily using the reported system, obtaining the corresponding breakthrough curves, and showing the ion-exchange mechanism among the different metals. Analytical performance is verified against conventional spectroscopic techniques, with good concordance of the obtained breakthrough curves and modeled adsorption parameters.

Potentiometric electronic tongue-flow injection analysis system for the monitoring of heavy metal biosorption processes.

An automated flow injection potentiometric (FIP) system with electronic tongue detection (ET) is used for the monitoring of biosorption processes of heavy metals on vegetable wastes. Grape stalk wastes are used as biosorbent to remove Cu(2+) ions in a fixed-bed column configuration. The ET is formed by a 5-sensor array with Cu(2+) and Ca(2+)-selective electrodes and electrodes with generic response to heavy-metals, plus an artificial neural network response model of the sensor's cross-response. The real-time monitoring of both the Cu(2+) and the cation exchanged and released (Ca(2+)) in the effluent solution is performed by using flow-injection potentiometric electronic tongue system. The coupling of the electronic tongue with automation features of the flow-injection system allows us to accurately characterize the Cu(2+) ion-biosorption process, through obtaining its breakthrough curves, and the profile of the Ca(2+) ion release. In parallel, fractions of the extract solution are analysed by spectroscopic techniques in order to validate the results obtained with the reported methodology. The sorption performance of grape stalks is also evaluated by means of well-established sorption models.

Cerclaje profiláctico en mujeres con nacimientos prematuros espontáneos previos, asociados con infección bacteriana ascendente / Prophylactic cerclage in women with spontaneous premature deliveries associated to ascending bacterial infection

Objetivo: Determinar la eficacia del cerclaje cervical profiláctico en pacientes con embarazos únicos, cérvix >25 mm e historia de nacimientos prematuros espontáneos, asociados con infección bacteriana ascendente (IBA). Métodos: Estudio clínico en pacientes con embarazos únicos y partos prematuros y/o abortos de 2° trimestre espontáneos previos, sin partos de término, asociados con IBA. Se incluyeron los casos con longitud cervical de >25 mm al ingreso. Se comparó el cerclaje cervical hecho en pacientes derivadas antes de las 20 semanas, con el manejo expectante en mujeres enviadas después de esta edad gestacional y que mantuvieron longitud cervical >25 mm durante los controles. Se excluyeron embarazadas con cérvix <25 mm al ingreso del estudio, con acortamiento cervical <25 mm durante el manejo con conducta expectante y mujeres con nacimientos prematuros previos sin histología placentaria. Resultados: Se incluyeron 51 pacientes, 23 con cerclaje y 28 sin cerclaje. El cerclaje cervical profiláctico, redujo significativamente la frecuencia del nacimiento prematuro <37semanas (4,3 por ciento vs 35,7 por ciento), <34 semanas (4,3 por ciento vs 28,6 por ciento) y la corioamnionitis histológica (4,3 por ciento vs 32,1 por ciento), OR (IC95 por ciento) 0,08 (0,09-0,70), 0,11(0,01-0,99) y 0,01 (0,010,83), respectivamente. Conclusiones: En pacientes con nacimientos prematuros previos asociados con IBA, embarazo único y longitud cervical >25 mm, el cerclaje profiláctico, reduce la frecuencia del nacimiento prematuro <37 y <34 semanas y de la corioamnionitis histológica.

Aims: Determine the effectiveness of prophylactic cerclage in women with singleton pregnancies, cervix >25 mm and a history of spontaneous premature deliveries associated to ascending bacterial infection (ABI). Methods: Women with singleton pregnancies and history of preterm births, with no full term deliveries, associated to ABI. Cases with >25 mm cervical length at admission were included. Cervical cerclage performed on patients derived before 20 weeks of pregnancy was compared to the expectant management of women submitted at a later gestational stage with sustained cervical length of >25 mm. Pregnant women with <25 mm cervix at referral, with cervical shortening <25 mm at expectant management, and women with previous preterm birth without placental histology were excluded. Results: 51 patients were included, 23 with cerclage and 28 without cerclage. Prophylactic cerclage significantly reduced the frequency of premature birth <37 weeks, 4.3 percent vs 35.7 percent and <34 weeks, 4.3 percent vs 28.6 percent and histologic chorioamnionitis 4.3 percent vs 32.1percent (9/28), OR (95 percent CI) 0.08 (0.09-0.70), 0.11(0.01-0.99) and 0.01 (0.01-0.83), respectively. Conclusions: In patients with preterm births associated to ABI, singleton pregnancy and cervical length >25 mm, prophylactic cerclage reduces the frequency of premature delivery <37 and <34 weeks as well as histologic chorioamnionitis.

Computer controlled-flow injection potentiometric system based on virtual instrumentation for the monitoring of metal-biosorption processes.

A completely automated flow-injection system was developed for the monitoring of biosorption studies of Cu(II) ion on vegetable waste by-products. The system employed flow-through Cu(II)-selective electrodes, of epoxy-resin-CuS/Ag(2)S heterogeneous crystalline type, and computer controlled pumps and valves for the flow operation. Computer automation was done through a specially devised virtual instrument, which commanded and periodically calibrated the system, allowing for the monitoring of Cu(II) ions between 0.6 and 6530 mg L(-1) at a typical frequency of 15 h(-1). Grape stalk wastes were used as biosorbent to remove Cu(II) ions in a fixed-bed column with a sorption capacity of 5.46 mg g(-1), obtained by the developed flow system, while the reference determination performed by FAAS technique supplied a comparable value of 5.41 mg g(-1).

Oxidation by Fenton's reagent combined with biological treatment applied to a creosote-comtaminated soil.

In this study, we investigated the feasibility of using Fenton oxidation to remove sorbed polycyclic aromatic hydrocarbons (PAHs) in aged soil samples with creosote oil from a wood preserving site. The optimal dosage of reagents was determined by a statistical method, the central composite rotatable experimental design. The maximum PAH removal was 80% with a molar ratio of oxidant/catalyst equal to 90:1. In general low molecular weight PAHs (3 rings) were degraded more efficiently than higher molecular weight PAHs (4 and 5 rings). The hydrogen peroxide decomposition kinetic was studied in the presence of KH(2)PO(4) as stabilizer. The kinetic data were fitted to a simple model, the pseudo-first-order which describes the hydrogen peroxide decomposition. The PAH kinetic degradation was also studied, and demonstrated that non-stabilized hydrogen peroxide was consumed in less than 30 min, whilst PAH removal continued for up to 24h. In a second part of the work, a combined chemical and biological treatment of the soil was carried out and shown to be dependent on the pre-oxidation step. Different reagent doses (H(2)O(2):Fe) were used (10, 20, 40, 60:1) in the pre-treatment step. An excess of hydrogen peroxide resulted in a poor biological removal, thus the optimal molar ratio of H(2)O(2):Fe for the combined process was 20:1. The combined treatment resulted in a maximum total PAH removal of 75% with a 30% increase in removal due to the biodegradation step. The sample with highest PAH removal in the pre-oxidation step led to no further increase in removal by biological treatment. This suggests that the more aggressive chemical pre-oxidation does not favour biological treatment. The physico-chemical properties of the pollutants were an important factor in the PAH removal as they influenced chemical, biological and combined treatments.

Sorption kinetics of polycyclic aromatic hydrocarbons removal using granular activated carbon: intraparticle diffusion coefficients.

Granular activated carbon (GAC) was evaluated as a suitable sorbent for polycyclic aromatic hydrocarbons (PAHs) removal from aqueous solutions. For this purpose, kinetic measurements on the extraction of a family of six PAHs were taken. A morphology study was performed by means of a scanning electron microscopy (SEM) analysis of GAC samples. Analyses of the batch rate data for each PAH were carried out using two kinetic models: the homogenous particle diffusion model (HPDM) and the shell progressive model (SPM). The process was controlled by diffusion rate the solutes (PAHs) that penetrated the reacted layer at PAH concentrations in the range of 0.2-10 mg L(-1). The effective particle diffusion coefficients (D(eff)) derived from the two models were determined from the batch rate data. The Weber and Morris intraparticle diffusion model made a double contribution to the surface and pore diffusivities in the sorption process. The D(eff) values derived from both the HPMD and SPM equations varied from 1.1 x 10(-13) to 6.0 x 10(-14) m(2) s(-1). The simplest model, the pore diffusion model, was applied first for data analysis. The model of the next level of complexity, the surface diffusion model, was applied in order to gain a deeper understanding of the diffusion process. This model is able to explain the data, and the apparent surface diffusivities are in the same order of magnitude as the values for the sorption of functionalized aromatic hydrocarbons (phenols and sulphonates) that are described in the literature.

Factores asociados a lesiones cervicales o presencia del virus del papiloma humano en dos poblaciones de estudiantes de Lima / Factors associated to cervical lesions or presence of human papilloma virus in two populations of students from Lima

Objetivos: Determinar la prevalencia y factores asociados a lesiones cervicales o presencia del virus del papiloma humano (VPH) en mujeres estudiantes en educación superior de 18 a 26 años de Lima. Materiales y métodos: Se realizó un estudio de corte transversal, en dos universidades y un instituto superior tecnológico de Lima, durante los meses de agosto a diciembre del 2001. Se aplicó un cuestionario y se colectaron muestras para Papanicolaou (PAP) y detección del ADN de los VPH 6, 11, 16, 18 por el método de PCR (reacción en cadena de la polimerasa). Se incluyeron en el análisis 321 estudiantes que reportaron actividad sexual a quienes se tomó muestras para PAP y VPH. Resultados: La prevalencia de VPH (6, 11, 16, 18) fue de 8,4 por ciento, y para las lesiones cervicales fue 2,5 por ciento (diagnóstico a través del PAP). Las lesiones cervicales o presencia del VPH fueron más frecuentes en el grupo de 21 a 23 años (p= 0,024). La diferencia de edades (tres a más años) entre la pareja sexual de mayor edad y la participante se asoció significantemente con lesiones cervicales o presencia del VPH (OR:8,8; IC95:1,9-39,6). La edad de la primera relación sexual, número de parejas sexuales y uso de condón, no mostraron significancia estadística. Conclusiones: Las lesiones cervicales o presencia del VPH son frecuentes en esta población de mujeres jóvenes. La edad y la diferencia de edades con la pareja sexual de mayor edad se asociaron a las lesiones cervicales o presencia del VPH.

Objectives: To determine the prevalence and factors associated with cervical lesions or presence of human papilloma virus (HPV) in women students with higher education from 18 to 26 years. Materials and methods: A cross-sectional study in students from two universities and a technical institute in Lima were carried out from August through December 2001. We surveyed women and collected cervical samples for Pap smear and HPV DNA detection for the 6, 11, 16 and 18 strains using polymerase chain reaction (PCR). The analysis was limited to HPV DNA and Pap smear samples of the 321 sexuallyûactive students. Results: The prevalence of HPV (6, 11, 16, 18) was 8,4 per cent, and for cervical lesions were 2,5 per cent (by PAP smear). The cervical lesions or presence of HPV were more frequent in the group of 21 to 23 years (p= 0,024). The difference in age (three or more years) between the oldest sexual partner and the participant was associated significantly to cervical lesions or presence of HPV (OR:8,8; CI95:1,9-39,6). Age of first sexual intercourse, number of sexual partners and condom use, showed no statistical significance. Conclusions: Cervical lesions or presence of HPV are common in this population of young women. Age and the age difference with the oldest sexual partner were associated with cervical lesions or presence of HPV.