Multiscale analysis of lignocellulose recalcitrance towards OrganoCat pretreatment and fractionation.

BACKGROUND: Biomass recalcitrance towards pretreatment and further processing can be related to the compositional and structural features of the biomass. However, the exact role and relative importance to those structural attributes has still to be further evaluated. Herein, ten different types of biomass currently considered to be important raw materials for biorefineries were chosen to be processed by the recently developed, acid-catalyzed OrganoCat pretreatment to produce cellulose-enriched pulp, sugars, and lignin with different amounts and qualities. Using wet chemistry analysis and NMR spectroscopy, the generic factors of lignocellulose recalcitrance towards OrganoCat were determined. RESULTS: The different materials were processed applying different conditions (e.g., type of acid catalyst and temperature), and fractions with different qualities were obtained. Raw materials and products were characterized in terms of their compositional and structural features. For the first time, generic correlation coefficients were calculated between the measured chemical and structural features and the different OrganoCat product yields and qualities. Especially lignin-related factors displayed a detrimental role for enzymatic pulp hydrolysis, as well as sugar and lignin yield exhibiting inverse correlation coefficients. Hemicellulose appeared to have less impact, not being as detrimental as lignin factors, but xylan-O-acetylation was inversely correlated with product yield and qualities. CONCLUSION: These results illustrate the role of generic features of lignocellulosic recalcitrance towards acidic pretreatments and fractionation, exemplified in the OrganoCat strategy. Discriminating between types of lignocellulosic biomass and highlighting important compositional variables, the improved understanding of how these parameters affect OrganoCat products will ameliorate bioeconomic concepts from agricultural production to chemical products. Herein, a methodological approach is proposed.

OrganoCat Fractionation of Empty Fruit Bunches from Palm Trees into Lignin, Sugars, and Cellulose-Enriched Pulp.

The palm oil industry produces large amounts of empty fruit bunches (EFB) as waste. EFB are very recalcitrant toward further processing, although their valorization could create novel incentives and bio-economic opportunities for the industries involved. Herein, EFB have been successfully subjected to the OrganoCat pretreatment-using 2,5-furandicarboxylic acid as the biogenic catalyst-to fractionate and separate this lignocellulosic material into its main components in a single step. The pretreatment of EFB leads to the deacetylation and depolymerization of noncellulosic polysaccharides and to the partial delignification of the cellulosic fiber. The OrganoCat processing of EFB yielded 45 ± 0.5 wt % cellulose-enriched pulp, 20 ± 0.7 wt % extracted lignin, 3.8 ± 0.2 wt % furfural, and 11 ± 0.6 wt % hydrolyzed sugars. The obtained EFB-pulp showed high accessibility to cellulases, resulting in a glucan conversion of 73 ± 2% after 72 h (15 ± 2% after 1 h) with commercial cellulase cocktail (Accellerase 1500). Overall, the results suggest that the treatment of the EFB material using OrganoCat may create promising paths for the full valorization of EFBs.

Breastfeeding shows a protective trend toward adolescents with higher abdominal adiposity.

OBJECTIVE: The question of whether breastfeeding has a protective effect against the development of overweight or obesity later in life remains controversial, especially during adolescence. The objective was to assess the relationship between breastfeeding and adolescents' body composition. METHODS: The HELENA study is a cross-sectional study involving 3,528 adolescents from 10 European cities. The outcome measures were body weight and height, subscapular skinfolds as well as waist circumferences. Breastfeeding, smoking status, and parental socioeconomic status were assessed by self-administered questionnaires. Dietary intake was recorded using two 24-hour recall surveys. Two adjustment approaches were used: i) covariance analysis adjusted for confounding factors (propensity score adjustment) and ii) multivariate quantile regression. RESULTS: After adjustment, no significant associations were observed between breastfeeding and body composition parameters (BMI Z-score; sum of skinfolds; waist-to-height ratio). An adjusted quantile regression analysis showed a non-significant trend for a protective effect of breastfeeding toward the highest percentiles of adiposity in boys but not in girls. This is of particular interest with respect to the superiority of the waist-to-height ratio over waist circumference and BMI for detecting cardiometabolic risk factors. CONCLUSION: This first European study, including a large set of factors influencing adolescents' body composition, showed a non-significant trend toward a protective effect of breastfeeding on highest percentiles of adolescent's abdominal adiposity.

Impact of mother tongue and gender on overweight, obesity and extreme obesity in 24,989 Viennese children/adolescents (2-16 years).

The present survey aims at determining the prevalence of extreme obesity (defined as a body mass index (BMI) ≥ 99.5th percentile) for the first time in Austria and at investigating the relationship between weight status and mother tongue in a representative Viennese sample of 24,989 children and adolescents (2-16 years) with a percentage of approximately 46 % of migration background.Directly measured anthropometric data on body weight and height were collected and BMI was calculated. Prevalence of overweight, obesity and extreme obesity was determined for every subgroup according to mother tongue using the German national reference criteria by Kromeyer-Hauschild et al.In this sample, 2.1 % of all children and adolescents had to be classified as being extremely obese. More boys (2.3 %) than girls (1.9 %) suffered from extreme obesity (p = 0.048). Total 1.7 % of children and adolescents with German as their native language, 2.5 % of Turkish native speakers and 2.9 % of children and adolescents with another mother tongue were extremely obese (p ≤ 0.001). The highest prevalence of overweight or obesity was found in Turkish-native-speaking children and adolescents (p ≤ 0.001), whereas the lowest one was found in German-native-speaking children and adolescents (p ≤ 0.001).This large study clearly shows that extreme obesity is a common disease and largely neglected. Apparently, another native language than German, as an indicator for a migration background, may be associated with a substantially higher probability for the development of extreme obesity in Vienna, Austria. Thus, effective preventive measures to overcome obesity are urgently needed.

Main characteristics and participation rate of European adolescents included in the HELENA study.

BACKGROUND: Participation rate and response rate are key issues in a cross sectional large-scale epidemiological study. The objective of this paper is to describe the study population and to evaluate participation and response rate as well as the key nutritional status variables in male and female adolescents involved in the HELENA study. METHODS: A multi-stage random cluster sampling with a target sample of 3000 adolescents aged [12.5 to 17.5] years, stratified for geographical location and age, was carried out. Information for participants and non-participants (NP) was compared, and participation and response rates to specific questionnaires were discussed. RESULTS: 3,865 adolescents aged [12.5 to 17.5] years (1,845 females) participated in the HELENA study, of whom 1,076 (568 females) participated in the blood sampling. 3,528 (1,845 females) adolescents were finally kept for statistical analysis. Participation rates for the schools and classes differed importantly between countries. The participation rate of pupils within the participating classes also differed importantly between countries. Sex ratio, mean age and BMI were similar between NP and participating adolescents within each centre, and in the overall sample. For all the questionnaires included in the database, the response rate of questionnaires was high (more than 80% of questions were completed). CONCLUSION: From this study it could be concluded that participation rate differed importantly between countries, though no bias could be identified when comparing the key study variables between participants and non-participants. Response rate for questionnaires was very high. Future studies investigating lifestyle and health in adolescents can optimize their methods when considering the opportunities and barriers observed in the HELENA study.

Can differences in physical activity by socio-economic status in European adolescents be explained by differences in psychosocial correlates? A mediation analysis within the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study.

OBJECTIVE: Socio-economic status (SES) has been positively associated with physical activity (PA) levels in adolescents. In order to tackle these social inequalities, information is needed about the underlying mechanisms of this association. The present study aimed to investigate the potential mediating role of psychosocial correlates of PA on the relationship between SES and PA in European adolescents. DESIGN: Cross-sectional study testing the mediating role of psychosocial correlates in the SES-PA association using the product-of-coefficients test of MacKinnon. SETTING: Ten European cities in nine different countries, the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study. SUBJECTS: Adolescents (n 2780) aged 12·5-17·49 years self-reported on PA (moderate-to-vigorous intensity PA and total PA), SES indicators (education of the mother and Family Affluence Scale) and psychosocial correlates of PA (stage of change, attitudes, awareness, modelling, social support, self-efficacy, benefits, barriers and environmental correlates). RESULTS: SES (Family Affluence Scale) was significantly associated with moderate-to-vigorous intensity PA. According to single-mediator models, this association was significantly mediated by stage of change (t = 3·6, P ≤ 0·001), awareness (t = 2·7, 0·001 < P ≤ 0·01), modelling (t = 4·8, P ≤ 0·001), self-efficacy (t = 2·5, 0·01

European adolescents' level of perceived stress and its relationship with body adiposity--the HELENA Study.

BACKGROUND: Since stress is hypothesized to be involved in the aetiology of obesity, the present study examined the current perception of stress in European adolescents and the association between adolescent perceived stress and their adiposity. METHODS: Observational data from 1121 adolescents aged 12.5-17.5 years from six European cities involved in the Healthy Lifestyle in Europe by Nutrition in Adolescence cross-sectional study, was investigated. The adolescents completed the adolescent stress questionnaire, comprising 10 different stress dimensions. Anthropometric measurements (weight, height, skinfold thicknesses and circumferences) and bioelectrical impedance analysis were performed, and personal characteristics (age, pubertal stage and parental education) were collected. The measures of perceived stress were described for boys and girls separately and gender differences were investigated. Associations between the adolescents' perceived stress and indicators of general (body mass index z-score, sum of skinfold thicknesses and body fat%) and abdominal (waist and hip circumference, and waist/height ratio) adiposity were examined using hierarchical linear models. RESULTS: While girls reported systematically higher levels of stress compared with boys, their stress profiles were similar, with highest levels for school-related stress followed by future uncertainty. Only in girls, perceived stress was significantly associated with increased measures of general and abdominal adiposity. In boys, no relationship between perceived stress and adiposity measures was observed. CONCLUSIONS: School is reported to be an important source of adolescent stress and should be the focus of stress management campaigns. Only in girls, the hypothesis that stress might be involved in the aetiology of obesity during adolescence was supported.

Reliability and validity of the Adolescent Stress Questionnaire in a sample of European adolescents--the HELENA study.

BACKGROUND: Since stress is hypothesized to play a role in the etiology of obesity during adolescence, research on associations between adolescent stress and obesity-related parameters and behaviours is essential. Due to lack of a well-established recent stress checklist for use in European adolescents, the study investigated the reliability and validity of the Adolescent Stress Questionnaire (ASQ) for assessing perceived stress in European adolescents. METHODS: The ASQ was translated into the languages of the participating cities (Ghent, Stockholm, Vienna, Zaragoza, Pecs and Athens) and was implemented within the HELENA cross-sectional study. A total of 1140 European adolescents provided a valid ASQ, comprising 10 component scales, used for internal reliability (Cronbach α) and construct validity (confirmatory factor analysis or CFA). Contributions of socio-demographic (gender, age, pubertal stage, socio-economic status) characteristics to the ASQ score variances were investigated. Two-hundred adolescents also provided valid saliva samples for cortisol analysis to compare with the ASQ scores (criterion validity). Test-retest reliability was investigated using two ASQ assessments from 37 adolescents. RESULTS: Cronbach α-values of the ASQ scales (0.57 to 0.88) demonstrated a moderate internal reliability of the ASQ, and intraclass correlation coefficients (0.45 to 0.84) established an insufficient test-retest reliability of the ASQ. The adolescents' gender (girls had higher stress scores than boys) and pubertal stage (those in a post-pubertal development had higher stress scores than others) significantly contributed to the variance in ASQ scores, while their age and socio-economic status did not. CFA results showed that the original scale construct fitted moderately with the data in our European adolescent population. Only in boys, four out of 10 ASQ scale scores were a significant positive predictor for baseline wake-up salivary cortisol, suggesting a rather poor criterion validity of the ASQ, especially in girls. CONCLUSIONS: In our European adolescent sample, the ASQ had an acceptable internal reliability and construct validity and the adolescents' gender and pubertal stage systematically contributed to the ASQ variance, but its test-retest reliability and criterion validity were rather poor. Overall, the utility of the ASQ for assessing perceived stress in adolescents across Europe is uncertain and some aspects require further examination.

Bariatric surgery in morbidly obese adolescents: long-term follow-up.

OBJECTIVE: Morbid obesity is an increasingly common disease in the industrialized world and poses a great challenge to the medical community. Many obese adolescents have undergone various conservative treatment methods without adequate success so that a surgical approach became necessary. We report on 18 patients who underwent bariatric surgery as well as a long-term follow-up program. METHODS: Eight patients received a laparoscopic adjustable gastric banding (LAGB). Four of these had to undergo a gastric bypass surgery (GByp) as second procedure due to insufficient weight loss. Nine patients primarily received a gastric bypass. RESULTS: LAGB: Mean weight loss after 24 months was 20 ± 6.3 kg. Four of the patients showed a regain in weight leading to a mean weight loss of 9 kg compared to initial weight after 53.3 months mean in this group. These patients had to undergo an additional gastric bypass procedure and lost 31 ± 18.3 kg after 18 months. GByp: Mean weight loss in nine patients after gastric bypass (primary procedure) was 31 ± 10.2 kg after 12 months and 36 ± 30.1 kg at the end of the observation time. Sleeve: Initial weight in this patient was 232 kg with a weight loss of 38 kg after 24 months. DISCUSSION AND CONCLUSION: It is remarkable that in four of eight patients who underwent LAGB had to undergo a second surgical procedure (GByp). No previous indicator, neither from a psychological nor from a medical point of view, could be detected. More long-term studies including psychological aspects seem to be necessary.

Nutritional knowledge in European adolescents: results from the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study.

OBJECTIVE: To build up sufficient knowledge of a 'healthy diet'. Here, we report on the assessment of nutritional knowledge using a uniform method in a large sample of adolescents across Europe. DESIGN: A cross-sectional study. SETTING: The European multicentre HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study conducted in 2006-2007 in ten cities in Austria, Belgium, France, Germany, Greece (one inland and one island city), Hungary, Italy, Spain and Sweden. SUBJECTS: A total of 3546 adolescents (aged 12·5-17·5 years) completed a validated nutritional knowledge test (NKT). Socio-economic variables and anthropometric data were considered as potential confounders. RESULTS: NKT scores increased with age and girls had higher scores compared with boys (62% v. 59%; P < 0·0001). Scores were approximately 10% lower in 'immigrant' adolescents or in adolescents with 'immigrant' mothers. Misconceptions with respect to the sugar content in food or in beverages were found. Overall, there was no correlation between BMI values and NKT scores. After categorization according to BMI, scores increased significantly with BMI group only in boys. These differences disappeared after controlling for socio-economic status (SES). Smoking status and educational level of the mother influenced the NKT scores significantly in boys, as well as the educational levels of both parents in girls. CONCLUSIONS: Nutritional knowledge was modest in our sample. Interventions should be focused on the lower SES segments of the population. They should be initiated at a younger age and should be combined with environmental prevention (e.g. healthy meals in school canteens).

Pilot evaluation of the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Food-O-Meter, a computer-tailored nutrition advice for adolescents: a study in six European cities.

OBJECTIVE: To investigate the feasibility and impact of the Food-O-Meter, an Internet-based computer-tailored nutrition intervention in adolescents. DESIGN: Participants in the intervention condition received the computer-tailored advice at baseline and at 1 month, those in the control condition received standardised advice. Effects were evaluated at 1 month (n 621) and at 3 months (n 558) using multi-level modelling. SETTING: Secondary schools in six European cities. Adolescents accessed the intervention in the school computer room under the supervision of teachers. SUBJECTS: Classes with students aged 12-17 years in the schools participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) cross-sectional study were randomised into intervention and control schools. RESULTS: In most participating centres the intervention was feasible and generally well appreciated, especially by girls. Technical problems and lack of motivation of the teachers hindered implementation in some centres. Overweight adolescents had higher scores for reading and using the advice than normal weight adolescents. After 1 month adolescents receiving the standardised advice reported an increase in fat intake, while fat intake in the intervention condition was stable (F = 4·82, P < 0·05). After 3 months, there was a trend in the total group for an intervention effect of the tailored advice on fat intake (F = 2·80, P < 0·10). In the overweight group there was a clear positive effect (F = 5·76, P < 0·05). CONCLUSIONS: The Food-O-Meter should be developed further. The results were modest but clear for percentage energy from fat, specifically in the overweight group. Adaptations based on new research are needed to enhance the reliability and effectiveness of the intervention.

Self-reported physical activity in European adolescents: results from the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) study.

OBJECTIVE: To describe self-reported physical activity (PA) patterns in the various domains (school, home, transport, leisure time) and intensity categories (walking, moderate PA, vigorous PA) in European adolescents. Furthermore, self-reported PA patterns were evaluated in relation to gender, age category, weight status category and socio-economic status (SES). DESIGN: Cross-sectional study. SETTING: Ten European cities. SUBJECTS: In total, 3051 adolescents (47·6 % boys, mean age 14·8 (sd 1·2) years) completed an adolescent-adapted version of the validated International Physical Activity Questionnaire. RESULTS: The total sample reported most PA during leisure time (485 min/week) and least PA at home (140 min/week). Boys reported significantly more school-based PA (P < 0·001), leisure-time PA (P = 0·003), vigorous PA (P < 0·001) and total PA (P = 0·002) than girls, while girls reported more home-based PA (P < 0·001) and walking (P = 0·002) than boys. Self-reported PA at school (P < 0·001), moderate PA (P < 0·001), vigorous PA (P < 0·001) and total PA (P < 0·001) were significantly higher in younger age groups than in older groups. Groups based on weight status differed significantly only in leisure-time PA (P = 0·004) and total PA (P = 0·003), while groups based on SES differed in all PA domains and intensities except transport-related PA and total PA. CONCLUSIONS: The total sample of adolescents reported different scores for the different PA domains and intensity categories. Furthermore, patterns were different according the adolescents' gender, age, weight status and SES.

Single and combined toxicity of pharmaceuticals at environmentally relevant concentrations in Daphnia magna--a multigenerational study.

Pharmaceuticals are continuously discharged into the environment, resulting in the chronic exposure of aquatic organisms to these compounds. In this multigenerational study, we examined the influence of four pharmaceuticals (carbamazepine (CBZ), diclofenac (DIC), 17alpha-ethinylestradiol (EE2) and metoprolol (MET)) as single substances and as a drug mixture at environmentally relevant concentrations on life-history and morphological parameters over six generations of the cladoceran Daphnia magna. Detectable effects of the used pharmaceuticals occured in the first observed generation, followed by an acclimation period and a recurrence of drug effects in later generations: daphnids exposed to MET were affected by the pharmaceutical, resulting in a decreased body length at first reproduction in the generations F0, F3 and F4 and in a reduced number of offspring in the generations F0 and F4. Similar effects were observed in daphnids exposed to EE2. DIC delayed age at first reproduction in the F0 and F2 generations and increased the body length of neonates in the generations F1 and F5. Daphnids exposed to CBZ showed a delay in the age at first reproduction for the F0 generation only. The drug mixture reduced the age at first reproduction of daphnids in the F0 and F2 generation and increased the body length at first reproduction in the generations F0 and F3. Neither the single drugs nor the pharmaceutical mixture influenced the successive generations of D. magna in a steady way. Thus, multigenerational studies are necessary to prevent insufficient assessments on the impact of pharmaceuticals in aquatic ecosystems.

Bariatric surgery in morbidly obese adolescents: a 4-year follow-up of ten patients.

INTRODUCTION: In cases that do not respond to non-surgical multidisciplinary treatment regimes, it seems the only possibility to offer bariatric surgical procedures. METHODS: All ten patients (17.3+/-3 years old; body mass index (BMI): 49.1+/-6.8 kg/m(2)), who underwent bariatric surgery because of their morbid obesity at the Medical University of Vienna were included in the study and underwent medical care, psychological and nutritional treatment from a physician, a psychologist, and a nutrition expert before and after surgery (follow-up for a mean of 41+/-15.6 months) at regular intervals. RESULTS: In total, all patients had a BMI loss of -10.33 kg/m(2), standard deviation, SD+/-6.6 (range from -3.3 to -25.07) at follow-up after 41 months, SD+/-15 months (range from 3 to 57), two patients dropped out because of lack of compliance. From a psychological perspective, the actual psychological condition was measured by five different psychological tests, e.g., 80% had a high score for depression, and 40% had negative self-acceptance. DISCUSSION: The laparascopic gastric banding operation was not as effective in weight reduction as expected. We have to turn our attention to compliance, postoperative treatment and the psychological component.

Influence of fish on habitat choice of water birds: a whole system experiment.

It is notoriously difficult to study population interactions among highly mobile animals that cannot be meaningfully confined to experimental plots of limited size. For example, migratory water birds are believed to suffer from competition with resident fish populations for shared food resources. While observational evidence in support of this hypothesis is accumulating, replicated experiments addressing this issue at the proper spatial scale are lacking. Here, we report from a replicated whole-system experiment in which we stocked large (0.07 km2), shallow (< or =2.5 m deep), highly eutrophic ponds in the bird protection area "Ismaninger Speichersee mit Fischteichen" with different densities of carp and assessed the responses of water birds and their food resources during summer over several years. In all years, the biomasses of benthic macroinvertebrates, macroalgae, and macrophytes as well as the densities of herbivorous, carnivorous, and omnivorous water birds were reduced in carp ponds compared to fishless ponds. The negative effects of carp on food resources and on the numbers of water birds feeding in carp ponds increased over the season (May-September) and were stronger at high than at low stocking densities of carp. Consequently, differences in resource densities between ponds with and without carp increased, and the ranking of ponds with respect to resource densities became more predictable over the season. These factors may have contributed to a seasonal improvement of the birds' abilities to track resource densities across ponds, as suggested by tight correlations of bird numbers on ponds with resource densities late, but not early, in the season.

PRESTO--Prevention Study of Obesity: a project to prevent obesity during childhood and adolescence.

The PRESTO project has been launched as a school-oriented pilot project. The aims were to influence nutrition, physical activity and health. The intervention was performed by a multiprofessional team and covered 11 nutrition and health-related sessions with 1 h per week in each class. The initial poor knowledge was improved significantly to the control group with better results in grammar schools compared to comprehensive schools. BMI was not improved in overweight children. However, this project could serve as a successful model in Austria.