Clinical course of neonatal acute kidney injury: multi-center prospective cohort study.

BACKGROUND: Neonatal acute kidney injury (AKI) has been associated with unfavorable outcomes, including increased mortality. We aimed to describe the clinical course and outcomes during the first 7 days after diagnosis in newborns with AKI in three neonatal intensive care units in Popayán-Colombia. METHODS: Multi-center prospective cohort study conducted between June 2019 and December 2020 in three NICUs after ethical approval. We included newborns between 2 and 28 days of life, first diagnosed with AKI using the KDIGO classification modified for newborns which consider increased serum creatinine values over baseline values as well as urine output over time in hours or both. Patients with chromosomal abnormalities, major kidney malformations, and complex congenital heart disease were excluded. Patients were followed for up to 7 days after diagnosis and the maximum KDIGO stage, recovery of kidney function, need for renal replacement therapy and cumulative incidence of death were evaluated. RESULTS: Over the 18 months of the study, 4132 newborns were admitted to the NICUs, and 93 patients (2.25, 95% CI 1.82-2.75%) developed neonatal AKI. 59.1% of the newborns were premature and there were no differences in severity according to gestational age. During follow-up, the maximum KDIGO was 64.5% for AKI-stage 1, 11.8% for AKI-stage 2, and 23.7% for AKI-stage 3. Kidney function recovery was higher in AKI-stage 1 patients vs. AKI-severe (AKI-stage 2 and 3) (95% vs. 48.5%). Five patients (5.4%) received renal replacement therapy and 15 died (16.1%), four in AKI-stage 1 vs. 11 in AKI-severe (6.7% vs 33.3%). CONCLUSIONS: Newborns admitted to the NICUs can develop AKI regardless of gestational age, and it is more frequent between the second and ninth days of life. More patients whit AKI-stage 1 recover and die less than those in a severe stage.

Evaluation of a commercially available organic acid product on body weight loss, carcass yield, and meat quality during preslaughter feed withdrawal in broiler chickens: a poultry welfare and economic perspective.

The effect of a commercial organic acid (OA) product on BW loss (BWL) during feed withdrawal and transportation, carcass yield, and meat quality was evaluated in broiler chickens. Two experiments were conducted in Brazil. Commercial houses were paired as control groups receiving regular water and treated groups receiving OA in the water. Treated birds had a reduction in BWL of 37 g in experiment 1 and 32.2 g in experiment 2. In experiment 2, no differences were observed in carcass yield between groups. Estimation of the cost benefit suggested a 1:16 ratio by using the OA. In experiment 3, conducted in Mexico, significant differences on water consumption, BWL, and meat quality characteristics were observed in chickens that were treated with the OA (P < 0.05). These data suggest this OA product may improve animal welfare and economic concerns in the poultry industry by reducing BWL and improving meat quality attributes.

Startup and long-term performance of biotrickling filters packed with polyurethane foam and poplar wood chips treating a mixture of ethylmercaptan, H2S, and NH3.

UNLABELLED: Treatment of a mixture of NH3, H2S, and ethylmercaptan (EM) was investigated for more than 15 months in two biotrickling filters packed with poplar wood chips and polyurethane foam. Inlet loads ranging from 5 to 10 g N-NH3 m-3 hr-1, from 5 to 16 g S-H2S m-3 hr-1, and from 0 to 5 g EM m-3 hr-1 were applied. During startup, the biotrickling filter packed with polyurethane foam was re-inoculated due to reduced biomass retention as well as a stronger effect of nitrogen compounds inhibition compared with the biotrickling filter packed with poplar wood. Accurate pH control between 7 and 7.5 favored pollutants abatement. In the long run, complete NH3 removal in the gas phase was achieved in both reactors, while H2S removal efficiencies exceeded 90%. EM abatement was significantly different in both reactors. A systematically lower elimination capacity was found in the polyurethane foam bioreactor. N fractions in the liquid phase proved that high nitrification rates were reached throughout steady-state operation in both bioreactors. CO2 production showed the extent of the organic packing material degradation, which allowed estimating its service lifetime in around 2 years. In the long run, the bioreactor packed with the organic packing material had a lower stability. However, an economic analysis indicated that poplar wood chips are a competitive alternative to inorganic packing materials in biotrickling filters. IMPLICATIONS: We provide new insights in the use of organic packing materials in biotrickling filters for the treatment of H2S, NH3, and mercaptans and compare them with polyurethane foam, a packing commonly used in biotrickling filters. We found interesting features related with the startup of the reactors and parameterized both the performance under steady-state conditions and the influence of the gas contact time. We provide relevant conclusions in the profitability of organic packing materials under a biotrickling filter configuration, which is infrequent but proven reliable from our research results. The report is useful to designers and users of this technology.

Effect of different concentrations of acetic, citric, and propionic acid dipping solutions on bacterial contamination of raw chicken skin.

Bacterial contamination of raw, processed poultry may include spoilage bacteria and foodborne pathogens. We evaluated different combinations of organic acid (OA) wash solutions for their ability to reduce bacterial contamination of raw chicken skin and to inhibit growth of spoilage bacteria and pathogens on skin during refrigerated storage. In experiment 1, raw chicken skin samples were dipped into a suspension of either 10(8) cfu/mL of Salmonella Typhimurium, Escherichia coli O157:H7, or Listeria monocytogenes for 30 s and then immersed in PBS or an OA wash solution mixture of 0.8% citric, 0.8% acetic, and 0.8% propionic acid (at equal wt/vol concentrations) for an additional 30 s. In experiment 2, three different concentrations of the OA wash solution (0.2, 0.4, and 0.6% at equal wt/vol concentrations) were tested against chicken skin samples contaminated with Salmonella Typhimurium. Viable pathogenic bacteria on each skin sample were enumerated after 1 and 24 h of storage at 4°C in both experiments. In experiment 3, skin samples were initially treated on d 1 with PBS or 2 concentrations of the OA mixture (0.4 and 0.8%), and total aerobic bacteria were enumerated during a 2-wk storage period. In all experiments, significant (P < 0.05) differences were observed when skin samples were treated with the OA wash solution and no spoilage organisms were recovered at any given time point, whereas increasing log10 numbers of spoilage organisms were recovered over time in PBS-treated skin samples. These results suggest that 0.2 to 0.8% concentrations of an equal-percentage mixture of this OA combination may reduce pathogens and spoilage organisms and improve food safety properties of raw poultry.

Technical and economic analysis of real anaerobic digester centrate by means of partial nitrification and sustainable heterotrophic denitrification.

The reliability of partial nitrification coupled with heterotrophic denitrification for the treatment of real anaerobic digester centrate produced in a wastewater treatment plant was technically and economically assessed in two sequencing batch reactors. Removal efficiencies above 90% were consistently achieved at N-ammonium loads above 1.2 g N L⁻¹ d⁻¹. Ethanol, affluent from a waste water treatment plant (biological treatment inlet) and a zero-cost liquid residue from a chemical industry containing polyethylene glycol and sorbitol were employed as carbon source for denitrification. In this last case, a total organic carbon (TOC) requirement of 4.5 g TOC g⁻¹ NO2⁻-N was calculated. The denitrification rate was 0.26 g NO2⁻-N g VSS⁻¹ d⁻¹ (VSS: volatile suspended solids). These results show that a carbon-rich waste can serve as a no-cost feed for denitrifying bioreactors. An in-depth economic analysis considering the main investment and operating costs of the process was developed, showing that it can suppose yearly savings above 50% with respect to the most widely used alternative of returning anaerobic digester centrate untreated to the head of the facility.

Economical assessment of the design, construction and operation of open-bed biofilters for waste gas treatment.

A protocol was developed with the purpose of assessing the main costs implied in the set-up, operation and maintenance of a waste gas-treating conventional biofilter. The main operating parameters considered in the protocol were the empty bed residence time and the gas flow rate. A wide variety of investment and operating costs were considered. In order to check its reliability, the protocol was applied to a number of scenarios, with biofilter volumes ranging from 8.3 to 4000 m(3). Results show that total annualized costs were between 20,000 and 220,000 euro/year and directly dependent, among other factors, on the size of the system. Total investment and operating costs for average-size compost biofilters were around 60,000 euro and 20,000 euro/year, respectively, which are concordant with actual costs. Also, a sensitivity analysis was performed in order to assess the relative influence of a series of selected costs. Results prove that operating costs are those that influence the total annual costs to a higher extent. Also, packing material replacement costs contribute significantly to the total yearly costs in biofilters with a volume higher than 800 m(3). Among operating costs, the electricity consumption is the main influencing factor in biofilters with a gas flow rate above 50,000 m(3)/h, while labor costs are critical at lower gas flow rates. In addition, the use of a variety of packing materials commonly employed in biofiltration was assessed. According to the results obtained, special attention should be paid to the packing material selected, as it is the main parameter influencing the medium replacement costs, and one of the main factors affecting investment costs.

Removal of formaldehyde, methanol, dimethylether and carbon monoxide from waste gases of synthetic resin-producing industries.

The removal of mixtures of gas-phase pollutants released from formaldehyde- and formaldehyde resin-producing industries was studied in different bioreactor systems. The waste gases contained formaldehyde, methanol, dimethylether and carbon monoxide. The use of a hybrid two-stage bioreactor, composed of a biotrickling filter and a conventional biofilter connected in series, led to very high elimination capacities and removal efficiencies close to 100% for overall pollutant loads exceeding 600g m(-3)h(-1). The presence of low concentrations of dimethylether in the gaseous mixture did not have a significant effect on the removal of formaldehyde or methanol under our operating conditions, although moderate concentrations of these compounds did negatively affect the biodegradation of dimethylether. When a mixture of all four compounds, at concentrations around 100, 100, 50 and 50mg m(-3) for formaldehyde, methanol, carbon monoxide and dimethylether, respectively, was fed to a conventional biofilter, removal efficiencies higher than 80% were obtained for the first three pollutants at empty bed retention time values above 30s. On the other hand, dimethylether was removed to a lower extent, although its reduced environmental impact allows to conclude that these results were satisfactory.

[Recurrent wheezing in three year-olds: facts and opportunities]. / Sibilancias recurrentes en menores de tres años: evidencias y oportunidades.

The 3 year-old group of children has an increased incidence and prevalence of recurrent wheezing episodes. There are different subgroups, who give different inflammatory responses to different triggering agents, and subgroups that differ in aetiopathology and immunopathology. Current diagnostic methods (exhaled nitric oxide in multiple breaths, nitric oxide in exhaled air condensate, induced sputum, broncho-alveolar lavage and endo-bronchial biopsy), enable the inflammatory pattern to be identified and to give the most effective and safe treatment. The various therapeutic options for treatment are reviewed, such as inhaled glucocorticoids when the inflammatory phenotype is eosinophilic, and leukotriene receptor antagonists, when the inflammatory phenotype is predominantly neutrophilic. In accordance with the current recommendations, for the diagnosis as well as for the therapy initiated in children of this age, they must be regularly reviewed, so that if the benefit is not clear, the treatment must be stopped and an alternative diagnosis and treatment considered. The start of treatment should be determined depending on the intensity and frequency of the symptoms, with the aim of decreasing morbidity and increasing the quality of life of the patient.

[Fractional exhaled nitric oxide: validation of a 6 second exhalation time with two different analysers]. / Fracción exhalada de óxido nítrico: validación de la medida con tiempo de espiración de 6 s con dos analizadores diferentes.

OBJECTIVE: To validate the measurement of fractional exhaled nitric oxide concentration (FE(NO)) using a 6-sec exhalation time in patients aged between 5 and 17 years with a stationary chemiluminescence analyser (NIOX, Aerocrine) and a portable electrochemical analyser (NIOX-MINO, Aerocrine). MATERIAL AND METHODS: FE(NO) was assessed in 60 patients randomised into two groups. In Group 1 (n = 30, NIOX analyser), three valid FE(NO) measurements were obtained for two exhalation times (10 sec and 6 sec); the mean of the three measurements was recorded. In Group 2 (n = 30, NIOX-MINO), a single valid measurement of FE(NO) was obtained for each exhalation time. We analysed age, gender, weight, height, diagnosis, treatment, FE(NO) and the number of attempts with both exhalation times in each analyser. Agreement between FE(NO) assessed using 10-sec and 6-sec exhalations was assessed by Bland-Altman analysis and Cohen's kappa. RESULTS: The mean (SD) age in Group 1 was 10.1 (3.07) years. The mean age in Group 2 was 10.43 (2.94) years. Bland-Altman analysis demonstrated good agreement between FE(NO) values obtained with both exhalation times and with both devices. Cohen's kappa, also demonstrated good agreement (NIOX, kappa = 1; NIOX-MINO, kappa = 0.93). CONCLUSIONS: A 6-sec exhalation time is valid for measuring FE(NO) with both analysers in children aged over 5 years.

[Spanish version of the TNO-AZL preschool children quality of life questionnaire (TAPQOL)]. / Versión española del TAPQOL: calidad de vida relacionada con la salud en niños de 3 meses a 5 años.

OBJECTIVES: To obtain a Spanish version of the TNO-AZL Preschool Children Quality of Life Questionnaire (TAPQOL) that would be both semantically and culturally equivalent to the original. MATERIAL AND METHODS: The TAPQOL questionnaire was designed to measure health-related quality of life in children aged 3 months to 5 years and contains 43 questions distributed in 12 subdimensions. The Spanish version was obtained by using the forward/back-translation method with expert, bilingual translators. Cognitive debriefing interviews were carried out with the parents of healthy children and with those of children with respiratory disease. RESULTS: During the adaptation phase, four items were modified after input from the authors of the original version to retain the meaning of the original. At the end of the adaptation process, 37 of the 43 items were classified as A, i.e. without difficulty in the adaptation. Four mothers and two fathers participated in the cognitive debriefing interviews. Four had secondary level education, and two had university level education. Their children were aged between 16 and 60 months. The average time taken to complete the questionnaire was 13.5 minutes. No comprehension problems regarding the questionnaire's content were found, and no items were modified after this phase of the study. The mothers of children with respiratory disease considered the questions related to their children's symptoms to be appropriate. CONCLUSIONS: The Spanish version of the TAPQOL has proven to be acceptable and culturally equivalent to the original version. Future studies should investigate the psychometric properties of this questionnaire and compare them with those of the original version.

[Agreement between two devices for measuring exhaled nitric oxide]. / Concordancia entre dos dispositivos de medida de óxido nítrico exhalado.

BACKGROUND: Measurement of fractional exhaled nitric oxide (FENO) is a non-invasive marker of eosinophilic airway inflammation that can be useful in asthma diagnosis and control, as well as in treatment monitoring. OBJECTIVE: We studied the correlation between two techniques for measuring FENO: the chemiluminescence-based analyzer (NIOX, Aerocrine, Sweden) and a new portable electrochemical sensor-based analyzer (NIOX-MINO, Aerocrine). MATERIAL AND METHODS: FENO was measured by the single breath on-line method. In all children, three consecutives measurements were obtained with NIOX, with a maximum of six attempts, and the arithmetic mean was calculated. Next, using NIOX-MINO, a single measurement was made successively in each of the children. The variables analyzed were sex, age, height, weight, diagnosis, treatment, NIOX-MINO value, mean of three values obtained with NIOX and the NO elimination rate (nL/min). For the statistical analysis, the Bland-Altman plot was used to compare the means and the differences between measurements of FENO from NIOX and NIOX-MINO. The agreement between the two analyzers was estimated by Cohen's Kappa statistic. RESULTS: Thirty children were included, 14 (46.67%) boys and 16 (53.33%) girls. The mean age was 11.3+/-3.09 years. All of the children successfully performed the measurements with two analyzers. The relationship between the means and the differences in the values obtained with NIOX-MINO and NIOX were statistically significant (p<0.005). In addition, Cohen's Kappa statistic (0.78) suggested a high degree of agreement between the results obtained with the two devices. CONCLUSIONS: The two analyzers, NIOX-MINO and NIOX, were not equivalent. There was good agreement between the FENO values measured with the two devices. Measurement of FENO with the portable electrochemical sensor-based analyzer (NIOX-MINO) is valid and feasible in children older than 5 years.

Effect of key parameters on the removal of formaldehyde and methanol in gas-phase biotrickling filters.

The effect of some important operation parameters, as pH, pollutant load and composition of the nutrient media, on the biodegradation of a mixture of formaldehyde and methanol in a gas-phase biotrickling filter was studied. pH proved to affect the degradation of both compounds at moderately acidic values. Replacing ammonium with nitrate as nitrogen source in the liquid solution led to a slight decrease in performance, though this difference was not really significant. A slight decrease in the elimination rate was also observed when reducing the N-NO(3)(-) concentration to 60% of its original value. No interactions between the two pollutants were found under our working conditions.

[Obstructive sleep apnea-hypopnea syndrome]. / Síndrome de apneas-hipopneas obstructivas del sueño.

We analyzed a cohort of 400 patients referred from the otorhinolaryngology department (40.05 %), primary care (PC) (36.52 %), and the pediatric pulmonary unit (17.63 %). The children were referred for clinical suspicion of apneas in 191 (47.87 %), snoring and apneas in 101 (25 %), and snoring in 87 (21.80 %). Adenotonsillar hypertrophy was found in 211 patients (52.75 %), tonsillar hypertrophy in 87 (21.75 %), and adenoid hypertrophy in 73 (18.25 %). All patients underwent respiratory polygraphy (RP) during sleep. Obstructive sleep apnea-hypopnea syndrome (OSAHS) was diagnosed in 298 patients (74.5 %). OSAHS was mild in 96 patients (24 %), moderate in 148 (37 %), and severe in 54 (13.5 %). The results of RP expressed in means plus standard deviation were as follows: number of apneas 21.38 (24.47), number of hypopneas 19.81 (20.74), apnea-hypopnea index per hour (AHI/h) 5.29 (7.10), mean oxygen saturation 94.60 (11.80), minimal saturation 83.14 (13.45), number of snores 98.27 (254.55), and snoring index per hour 5.68 (6.5). Significant differences were found between oxygen saturation and AHI/h per hour. No differences were found among age, mean oxygen saturation, area of residence, reason for consulting, and AHI/h. Adenotonsillectomy was performed in 289 patients (72.25 %) of the initial cohort. In conclusion, OSAHS in childhood is frequent. RP during sleep aids diagnosis. The main cause of OSAHS in children is adenotonsillar hypertrophy.

[Diagnostic utility of nocturnal in-home respiratory polygraphy]. / Rentabilidad de la poligrafía respiratoria del sueño realizada en el domicilio.

INTRODUCTION: Sleep apnea-hypopnea syndrome (SAHS) is relatively frequent in children. The gold standard for diagnosis is polysomnography. However, because of technical difficulties and the cost of this method, new alternatives have become available, such as respiratory polygraphy (RP) performed at home or in hospital, which have provided satisfactory results in children with clinical suspicion of SAHS. OBJECTIVE: The aim of this study was to analyze the diagnostic utility of in-home RP in the diagnosis of SAHS in a sample of boys and girls referred to the pediatric respiratory care department for suspected sleep apnea, snoring, or both. MATERIAL AND METHODS: In all patients, a history and physical examination were performed; X-ray of the chest and cavum and RP were carried out. The following qualitative variables were analyzed: place where RP was performed, the result, sex, the reason for consulting, place of residence, results of otorhinolaryngological examination, and treatment. The quantitative variables analyzed were age, total number of apneas, total number of hypopneas, apnea index/hour, hypopnea index/hour, mean and minimum SpxO2, number of snores per hour and the snore index/hour. Statistical analysis was performed using Pearson's chi-square test and Student's t-test. RESULTS: A total of 132 patients were studied, 44 (33.3 %) through in-home RP (group 1) and 88 (66.6 %) through in-hospital RP (group 2). In group 1, two recordings (4.5 %) were considered nonvalid. The mean age of the patients was 8.3 years (SD 3.02). The results [means (standard deviation)] of in-home RP were as follows: apnea-hypopnea index (AHI)/h: 3.4 (4.3); mean SpxO2: 97.3 (1.8); minimum SpxO2: 87.7 (10.3). In group 2, four recordings (4.5 %) were nonvalid. The mean age of the patients was 7.4 years (SD 3). The results of in-hospital RP were as follows: AHI/h: 4.45 (5.4); mean SpxO2: 96.8 (1.8); minimum SpxO2: 87 (11). No significant differences were found between the validity of in-home and in-hospital RP. Likewise, no significant differences were found between AHI/h, SpxO2 and in-home and in-hospital RP. CONCLUSION: In conclusion, in our sample, the diagnostic utility of in-home RP was equal to that of in-hospital RP. In-home RP allows the possibility of performing a more physiological sleep study and, by eliminating the cost of hospitalization, is more cost-efficient. Therefore, in-home RP is a valid and reliable technique for the diagnosis of childhood SAHS.

[Current prevalence of asthma in schoolchildren in San Sebastián (Spain)]. / Prevalencia actual de asma en escolares en San Sebastián.

OBJECTIVE: To determine the current prevalence of asthma in children aged 6-12 years old in San Sebastian (Guipuzcoa, Spain). PATIENTS AND METHODS: An observational, cross sectional study was performed in 6-12-year-old children in schools. The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was employed. Bronchial hyperresponsiveness was investigated using the free running test, with peak expiratory flow (PEF) measured with a peak flow meter as the main measurement. The ISAAC questionnaire (n = 919) was distributed to 460 boys (50.1%) and 459 girls (49.9%) with a mean age of 8 years (SD 1.87). The response rate to the questionnaire was 93 % (n = 855). Participation in the free running test was 90.8% (n = 835). A total of 89.88% of the children (n = 826) completed both tests. RESULTS: The questionnaire of symptoms and signs compatible with asthma revealed a current prevalence of asthma of 25.56% (n = 216) and a cumulative prevalence of 25.44% (n = 85). Nocturnal asthma was found in 29.37% (n = 47) and severe asthma in 9.27% (n = 14). Bronchial hyperresponsiveness was found in 23% of the participants. An epidemiological diagnosis of asthma (asthma-related symptoms plus bronchial hyperresponsiveness) was made in 6.54%. CONCLUSIONS: The current prevalence of asthma in 6-12-year-old schoolchildren in San Sebastian, determined through symptoms and signs compatible with asthma in the previous year and a positive free running test, is similar to that reported in other national studies.

[Measurement of CO diffusion capacity (II): Standardization and quality criteria]. / Medición de la difusión de CO (II): estandarización y criterios de calidad.

The diffusion capacity is the technique that measures the ability of the respiratory system for gas exchange, thus allowing a diagnosis of the malfunction of the alveolar-capillary unit. The most important parameter to assess is the CO diffusion capacity (DLCO). New methods are currently being used to measure the diffusion using nitric oxide (NO). There are other methods for measuring diffusion, although in this article the single breath technique is mainly referred to, as it is the most widely used and best standardized. Its complexity, its reference equations, differences in equipment, inter-patient variability and conditions in which the DLCO is performed, lead to a wide inter-laboratory variability, although its standardization makes this a more reliable and reproductive method. The practical aspects of the technique are analyzed, by specifying the recommendations to carry out a suitable procedure, the calibration routine, calculations and adjustments. Clinical applications are also discussed. An increase in the transfer of CO occurs in diseases in which there is an increased volume of blood in the pulmonary capillaries, such as in the polycythemia and pulmonary hemorrhage. There is a decrease in DLCO in patients with alveolar volume reduction or diffusion defects, either by altered alveolar-capillary membrane (interstitial diseases) or decreased volume of blood in the pulmonary capillaries (pulmonary embolism or primary pulmonary hypertension). Other causes of decreased or increased DLCO are also highlighted.

[Body plethysmography (I): Standardisation and quality criteria]. / Pletismografía corporal (I): estandarización y criterios de calidad.

Whole body plethysmography is used to measure lung volumes, capacities and resistances. It is a well standardised technique, and although it is widely used in paediatric chest diseases units, it requires specific equipment, specialist staff, and some cooperation by the patient. Plethysmography uses Boyle's law in order to measure the intrathoracic gas volume or functional residual capacity, and once this is determined, the residual volume and total lung capacity is extrapolated. The measurement of total lung capacity is necessary for the diagnosis of restrictive diseases. Airway resistance is a measurement of obstruction, with the total resistance being able to be measured, which includes chest wall, lung tissue and airway resistance, as well as the specific airway resistance, which is a more stable parameter that is determined by multiplying the measured values of airway resistance and functional residual capacity. The complexity of this technique, the reference equations, the differences in the equipment and their variability, and the conditions in which it is performed, has led to the need for its standardisation. Throughout this article, the practical aspects of plethysmography are analysed, specifying recommendations for performing it, its systematic calibration and the calculations that must be made, as well as the interpretation of the results obtained. The aim of this article is to provide a better understanding of the principles of whole body plethysmography with the aim of optimising the interpretation of the results, leading to improved management of the patient, as well as a consensus among the speciality.

Hydrodynamic behaviour and comparison of technologies for the removal of excess biomass in gas-phase biofilters.

The hydrodynamic behaviour of a biofilter fed toluene and packed with an inert carrier was evaluated on start-up and after long-term operation, using both methane and styrene as tracers in Residence Time Distribution experiments. Results indicated some deviation from ideal plug flow behaviour after 2-year operation. It was also observed that the retention time of VOCs gradually increased with time and was significantly longer than the average residence time of the bulk gas phase. Non-ideal hydrodynamic behaviour in packed beds may be due to excess biomass accumulation and affects both reactor modeling and performance. Therefore, several methods were studied for the removal of biomass after long-term biofilter operation: filling with water and draining, backwashing, and air sparging. Several flow rates and temperatures (20-60 degrees C) were applied using either water or different chemicals (NaOH, NaOCl, HTAB) in aqueous solution. Usually, higher flow rates and higher temperatures allowed the removal of more biomass, but the efficiency of biomass removal was highly dependent on the pressure drop reached before the treatment. The filling/draining method was the least efficient for biomass removal, although the treatment did basically not generate any biological inhibition. The efficiency of backwashing and air sparging was relatively similar and was more effective when adding chemicals. However, treatments with chemicals resulted in a significant decrease of the biofilter's performance immediately after applying the treatment, needing periods of several days to recover the original performance. The effect of manually mixing the packing material was also evaluated in duplicate experiments. Quite large amounts of biomass were removed but disruption of the filter bed was observed. Batch assays were performed simultaneously in order to support and quantify the observed inhibitory effects of the different chemicals and temperatures used during the treatments.

[Respiratory treatments in neuromuscular disease]. / Tratamientos respiratorios en la enfermedad neuromuscular.

In a previous article, a review was presented of the respiratory pathophysiology of the patient with neuromuscular disease, as well as their clinical evaluation and the major complications causing pulmonary deterioration. This article presents the respiratory treatments required to preserve lung function in neuromuscular disease as long as possible, as well as in special situations (respiratory infections, spinal curvature surgery, etc.). Special emphasis is made on the use of non-invasive ventilation, which is changing the natural history of many of these diseases. The increase in survival and life expectancy of these children means that they can continue their clinical care in adult units. The transition from pediatric care must be an active, timely and progressive process. It may be slightly stressful for the patient before the adaptation to this new environment, with multidisciplinary care always being maintained.

Electronic bolus design impacts on administration.

Electronic identification of animals has become increasingly important worldwide to improve and ensure traceability. In warm and hot climates, such as Brazil, boluses can have advantages over ear tags as the internal devices reduce the risks of ear tag losses, tissue damage, and lesions on the ear. Electronic boluses, however, are often perceived as having negative characteristics, including reported difficulties of administration in small ruminants. This paper describes the factors associated with bolus design that affect the swallowing of a bolus in sheep. Other factors that might influence bolus swallowing time have also been considered. In addition, the effect of bolus design on its performance was evaluated. A total of 56 Suffolk ewes were used to assess the ease of administration and retention of 3 types of electronic ruminal boluses (mini, 11.5 × 58.0 mm and 21.7 g; small, 14.8 × 48.5 mm and 29.5 g; standard, 19.3 × 69.8 mm and 74.4 g) during a whole productive year, including pregnancy and lamb suckling. Ewe age (5.6 ± 2.3 yr) and weight (85.07 ± 8.2 kg BW) were recorded, as well as time for bolus swallowing. The deglutition of the bolus and any resulting blockages in the esophagus were monitored by visual observations. Retention and readability of the boluses were regularly monitored for d 1, wk 1, mo 1, and every mo until 1 yr. Time for bolus swallowing differed substantially with bolus type and was greater (P < 0.05) for the standard bolus (32.8 ± 6.9 s) when compared to small and mini boluses, which did not differ (8.5 ± 2.0 vs. 9.2 ± 2.7 s; P > 0.05). The bolus o.d. and length were positively correlated with swallowing time (P < 0.01). The ewe weight was negatively correlated with swallowing time (P < 0.05). At 6 mo all electronic boluses showed 100% retention rate, and at 12 mo, bolus retention was 100%, 94.5%, and 100% for mini, small, and standard boluses, respectively (P > 0.05). At 12 mo, all boluses showed 100% readability, except for small boluses, which had a readability of 94.5%. In conclusion, bolus design affected swallowing time and bolus readability. A reduction in boluses length and o.d. needs to be carried out to provide ease of administration and for boluses to be used as an effective means of electronic identification. Therefore, this study shows that adequately designed boluses are safe and suitable for identifying adult sheep and can therefore be used in hot climates.