DIAGNOSTIC PERFORMANCE OF WAIST CIRCUMFERENCE MEASUREMENTS FOR PREDICTING CARDIOMETABOLIC RISK IN MEXICAN CHILDREN.

OBJECTIVE: The accumulation of abdominal fat is associated with cardiometabolic abnormalities. Waist circumference (WC) measurements allow an indirect evaluation of abdominal adiposity. However, controversy exists over which WC reference values are the most suitable for identifying the pediatric population at risk. The aim of the study was to evaluate the ability of various WC indices to identify abdominal obesity as diagnostic tools for predicting cardiometabolic risk in Mexican children and adolescents. METHODS: Anthropometric measurements were performed and biochemical profiles determined in a crosssectional study that included 366 children and adolescents. Four parameters were used to evaluate abdominal obesity in our study group: (1) WC >90th percentile, according to the Fernández reference in a Mexican-American population measured by the National Center for Health Statistics (NCHS) technique; (2) WC >90th percentile, according to the Klünder reference in a Mexican population (measured by the World Health Organization [WHO] technique); (3) waist-to-height ratio (WHtR) >0.5 according to WHO; and (4) WHtR >0.5 according to NCHS. The ability of each of the indices to discriminate cardiometabolic abnormalities (fasting plasma glucose, dyslipidemia, and hypertension) was assessed. RESULTS: WHtR >0.5 according to WHO or NCHS references showed greater sensitivity to detect metabolic abnormalities compared to percentile reference parameters (74.3 to 100% vs. 59.0 to 88.9%; P<.05). However, the percentiles displayed more specificity to identify these alterations (46.2 to 62.2 vs. 21.3 to 46.9; P<.05). Area under the curve analysis showed that WHtR >0.5 can more readily detect hypertriglyceridemia (0.642), hypoalphalipoproteinemia (0.700), and a combination of two or more metabolic abnormalities (0.661), whereas WC >90th percentile, according to Klünder, better detected hyperglycemia (0.555). CONCLUSION: WHtR >0.5 is a sensitive measure to identify pediatric patients with cardiometabolic alterations, despite its low specificity, and is a useful diagnostic tool to detect populations at risk. Based on the results of this study, we recommend preferential use of the Klünder waist circumference references over the Fernández method in Mexican pediatric populations. ABBREVIATIONS: AUC = area under the curve BMI = body mass index HDL = high-density lipoprotein IDF = International Diabetes Federation LDL = low-density lipoprotein MS = metabolic syndrome NCHS = National Center for Health Statistics ROC = receiver operating characteristic WC = waist circumference WHO = World Health Organization WHtR = waist-to-height ratio.

A study of torrefied cardboard characterization and applications: Composition, oxidation kinetics and methane adsorption.

Torrefaction is proposed as a valorization process for non recycled cardboard. Torrefied cardboard was physically and chemically characterized and it was proposed for energy production and methane adsorption. The surface area and pore volume obtained were among 3.0-6.0m2/g and 5.7·10-3-2.3·10-2cm3/g, respectively. The carbon content increased with temperature and residence time of torrefaction. Oxidation kinetics of torrefied cardboard at different temperatures (250-300°C) and at different plateaus (60-120min) were tested. Torrefied cardboard was chemically treated with KOH in order to study the effect of K on thermal oxidation kinetics. It was observed that high torrefaction temperatures and residence times lead to a more stable char. Furthermore, kinetic parameters were obtained by iso-conversional methods and Coats and Redfern method. Attending to iso-conversional method, a decrease of Ea was observed with both, temperature and residence time of torrefaction. Whereas chemically treated presented highest Ea values than torrefied cardboard. In addition, regarding Coats and Redfern method, the oxidation model was not highly modified by torrefaction temperature and residence time. However, for chemically treated samples the oxidation model was modified by K presence. Finally, CH4 adsorption capacity of torrefied cardboard was studied at 30°C and atmospheric pressure. CH4 partial pressures tested were lower than 0.45kPa. It was observed that CH4 adsorption capacity increased with torrefaction time and decreased with chemical treatment. Thus, for the tested samples, the highest adsorption capacity observed was 5.70mgCH4/g of sample.

The plant secondary metabolite citral alters water status and prevents seed formation in Arabidopsis thaliana.

Based on previous results, which showed that the secondary metabolite citral causes disturbances to plant water status, the present study is focused on demonstrating and detailing these effects on the water-related parameters of Arabidopsis thaliana adult plants, and their impact on plant fitness. Clear evidence of effects on water status and fitness were observed: plants treated with 1200 and 2400 µm citral showed decreased RWC, reduced Ψs , increased Ψw and reduced stomatal opening, even 7 days after the beginning of the experiment. Plant protection signals, such as leaf rolling or increased anthocyanin content, were also detected in these plants. In contrast, 14 days after beginning the treatment, treated plants showed signs of citral-related damage. Moreover, the reproductive success of treated plants was critically compromised, with prematurely withered flowers and no silique or seed development. This effect of citral on fitness of adult plants suggests a promising application of this natural compound in weed management by reducing the weed seed bank in the soil.

Value-added performance of processed cardboard and farm breeding compost by pyrolysis.

This study aims to underline the huge potential in Canada of adding value to cardboard and compost as a renewable fuel with a low ecological footprint. The slow pyrolysis process of lined cardboard and compost blend was investigated. Thermal behavior was investigated by thermogravimetric analysis coupled with mass spectrometry (TGA-MS). The thermal profiles are presented in the form of TGA/DTG curves. With a constant heating rate of 10 °C/min, two parameters, temperature and time were varied. Cardboard decomposition occurred mostly between 203 °C and 436 °C, where 77% of the sample weight was decomposed. Compost blend decomposition occurred mostly between 209 °C and 373 °C, with 23% of weight. The principal gaseous products that evolved during the pyrolysis were H2O, CO and CO2. As a result, slow pyrolysis led to the formation of biochar. High yield of biochar from cardboard was found at 250 °C for a duration of 60 min (87.5%) while the biochar yield from the compost blend was maintained constant at about 31%. Finally, kinetic parameters and a statistical analysis for the pyrolysis process of the cardboard and compost samples have been investigated. Both materials showed a favorable thermochemical behavior. However, unlike cardboard, compost pyrolysis does not seem a promising process because of the low superior calorific and biochar values.

Life cycle assessment of swine and dairy manure: pyrolysis and combustion processes.

The valorization of three different manure samples via pyrolysis and combustion processes was evaluated. Dairy manure (sample Pre) was biologically pretreated by anaerobic digestion (sample Dig R) whereas swine manure (sample SW) was pretreated by a biodrying process. Thermal behavior of manure samples were studied by means of thermogravimetric analysis coupled with mass spectrometry (TGA-MS). These processes could be divided into four general stages: dehydration, devolatilization, char transformation (oxidation for combustion) and inorganic matter decomposition. The main differences observed among the samples were attributed to their different composition and pretreatment. The economic feasibility, energetic and environmental impacts of pyrolysis and combustion technologies for dairy samples were carried out by means of life cycle assessment (LCA) methodology. Four different scenarios were analyzed. The economic feasibility of the pyrolysis process was demonstrated, being sample Dig R the best environmental option. However, the combustion of sample Pre was the best energetic option.

[Glenohumeral instability in patients over 40 years-old: injuries, treatment and complications]. / Inestabilidad glenohumeral en pacientes mayores de 40 años: lesiones, tratamiento y complicaciones.

INTRODUCTION: Recurrent shoulder dislocation is infrequent after forty years and presents different injuries than younger patients. OBJECTIVE: To compare injuries and complications after surgery between one group older than forty years of age and another younger group. MATERIAL AND METHODS: A review was made o all patients who had undergone arthroscopic surgery due to glenohumeral instability from 1999 until 2011. The mean follow-up was 64 months. The case group consisted of all patients older than 40 years at the time of the surgery (n=21), which was compared with a similar sized control group of randomly selected younger patients (n=27). RESULTS: The mean age in the older group was 54 years (SD 11.86), while it was 26 years (SD 5.80) in the younger group. No differences were founded between both groups in labrum injury, Hill-Sachs injury, and bone Bankart lesion (P>.05). Rotator cuff tears were 7.3 times (95% CI; 2.5-21.6) more frequent in the older group (81%) compared to the younger group (P<.05). However, neurological injuries after dislocation were not more frequent in this group. There was no significant difference between the complications after surgery and the age according to the design (P>.05). CONCLUSIONS: Anterior recurrent dislocation after forty years of age is usually associated with rotator cuff tears. Arthroscopic treatment of instability was effective with no more postoperative complications.

Thermogravimetric-mass spectrometric analysis on combustion of lignocellulosic biomass.

Combustion characteristics of biomass main components and three lignocellulosic biomass (fir wood, eucalyptus wood and pine bark) were investigated by thermogravimetric analysis coupled with mass spectrometry. The combustion of biomass was divided into two main steps, devolatilization and char oxidation stage. Heating rate effect was also studied. Generally, the higher the heating rate, the higher the decomposition temperature. Furthermore, the weight loss rate decreased due to particle temperature gradients. Combustion kinetics were studied. Models based on reaction order (Oi), nucleation (Ni) and diffusion (Di) achieved the best fitting to the experimental data. Cellulose oxidation presented the highest activation energies. CO, CO2 and H2O were the main components evolved from combustion. Additionally, light hydrocarbons (CH4 and C2H5) were also present. Finally, nitrogen compounds were in a higher proportion than sulfur compounds being released as primary amines and NOx.

Pyrolysis, combustion and gasification characteristics of Nannochloropsis gaditana microalgae.

Pyrolysis, combustion and gasification characteristics of Nannochloropsis gaditana microalgae (NG microalgae) were investigated by thermogravimetric analysis (TGA). NG microalgae pyrolysis and combustion could be divided into three main stages: dehydration, proteins and polysaccharides degradation and char decomposition. The effects of the initial sample mass, particle size and gas flow on the pyrolysis and combustion processes were studied. In addition, gasification operation conditions such as temperature, initial sample mass, particle size, sweep gas flow and steam concentration, were experimentally evaluated. The evolved gases were analyzed online using mass spectroscopy (MS). In pyrolysis and combustion processes, most of the gas products were generated at the second degradation step. N-compounds evolution was associated with the degradation of proteins. Furthermore, SO(2) release from combustion could be related to sulphated polysaccharides decomposition. The main products detected during gasification were CO(2), CO, H(2), indicating that oxidation reactions, water gas and water gas shift reactions, were predominant.

Thermogravimetric-mass spectrometric analysis of lignocellulosic and marine biomass pyrolysis.

The pyrolysis characteristics of three lignocellulosic biomasses (fir wood, eucalyptus and pine bark) and a marine biomass (Nannochloropsis gaditana microalgae) were investigated by thermogravimetric analysis coupled with mass spectrometry (TGA-MS). Thermal degradation of lignocellulosic biomass was divided into four zones, corresponding to the decomposition of their main components (cellulose, hemicellulose and lignin) and a first step associated to water removal. Differences in volatile matter and cellulose content of lignocellulosic species resulted in different degradation rates. Microalgae pyrolysis occurred in three stages due to the main components of them (proteins), which are greatly different from lignocellulosic biomass. Heating rate effect was also studied. The main gaseous products formed were CO(2), light hydrocarbons and H(2)O. H(2) was detected at high temperatures, being associated to secondary reactions (char self-gasification). Pyrolysis kinetics were studied using a multiple-step model. The proposed model successfully predicted the pyrolytic behaviour of these samples resulting to be statistically meaningful.