Drop formation and breakup of low viscosity elastic fluids: Effects of molecular weight and concentration

The dynamics of drop formation and pinch-off have been investigated for a series of low viscosity elastic fluids possessing similar shear viscosities, but differing substantially in elastic properties. On initial approach to the pinch region, the viscoelastic fluids all exhibit the same global necking behavior that is observed for a Newtonian fluid of equivalent shear viscosity. For these low viscosity dilute polymer solutions, inertial and capillary forces form the dominant balance in this potential flow regime, with the viscous force being negligible. The approach to the pinch point, which corresponds to the point of rupture for a Newtonian fluid, is extremely rapid in such solutions, with the sudden increase in curvature producing very large extension rates at this location. In this region the polymer molecules are significantly extended, causing a localized increase in the elastic stresses, which grow to balance the capillary pressure. This prevents the necked fluid from breaking off, as would occur in the equivalent Newtonian fluid. Alternatively, a cylindrical filament forms in which elastic stresses and capillary pressure balance, and the radius decreases exponentially with time. A (0+1)-dimensional finitely extensible nonlinear elastic dumbbell theory incorporating inertial, capillary, and elastic stresses is able to capture the basic features of the experimental observations. Before the critical "pinch time" t(p), an inertial-capillary balance leads to the expected 2/3-power scaling of the minimum radius with time: R-min similar to(t(p)-t)(2/3). However, the diverging deformation rate results in large molecular deformations and rapid crossover to an elastocapillary balance for times t>t(p). In this region, the filament radius decreases exponentially with time R-min similar to exp[(t(p)-t)/lambda(1)], where lambda(1) is the characteristic time constant of the polymer molecules. Measurements of the relaxation times of polyethylene oxide solutions of varying concentrations and molecular weights obtained from high speed imaging of the rate of change of filament radius are significantly higher than the relaxation times estimated from Rouse-Zimm theory, even though the solutions are within the dilute concentration region as determined using intrinsic viscosity measurements. The effective relaxation times exhibit the expected scaling with molecular weight but with an additional dependence on the concentration of the polymer in solution. This is consistent with the expectation that the polymer molecules are in fact highly extended during the approach to the pinch region (i.e., prior to the elastocapillary filament thinning regime) and subsequently as the filament is formed they are further extended by filament stretching at a constant rate until full extension of the polymer coil is achieved. In this highly extended state, intermolecular interactions become significant, producing relaxation times far above theoretical predictions for dilute polymer solutions under equilibrium conditions. (C) 2006 American Institute of Physics

Effect of a protein and energy dense n-3 fatty acid enriched oral supplement on loss of weight and lean tissue in cancer cachexia:A randomised double blind trial

Aim: N-3 fatty acids, especially eicosapentaenoic acid (EPA), may possess anticachectic properties. This trial compared a protein and energy dense supplement enriched with n-3 fatty acids and antioxidants (experimental: E) with an isocaloric isonitrogenous control supplement (C) for their effects on weight, lean body mass (LBM), dietary intake, and quality of life in cachectic patients with advanced pancreatic cancer. Methods: A total of 200 patients (95 E; 105 C) were randomised to consume two cans/day of the E or C supplement (480 ml, 620 kcal, 32 g protein ± 2.2 g EPA) for eight weeks in a multicentre, randomised, double blind trial. Results: At enrolment, patients' mean rate of weight loss was 3.3 kg/month. Intake of the supplements (E or C) was below the recommended dose (2 cans/day) and averaged 1.4 cans/day. Over eight weeks, patients in both groups stopped losing weight (Δweight E: -0.25 kg/month versus C: -0.37 kg/month; p=0.74) and LBM (ΔLBM E: +0.27 kg/month versus C: +0.12 kg/month; p=0.88) to an equal degree (change from baseline E and C, p<0.001). In view of evident non-compliance in both E and C groups, correlation analyses were undertaken to examine for potential dose-response relationships. E patients demonstrated significant correlations between their supplement intake and weight gain (r=0.50, p<0.001) and increase in LBM (r=0.33, p=0.036). Such correlations were not statistically significant in C patients. The relationship of supplement intake with change in LBM was significantly different between E and C patients (p=0.043). Increased plasma EPA levels in the E group were associated with weight and LBM gain (r=0.50, p<0.001; r=0.51, p=0.001). Weight gain was associated with improved quality of life (p<0.01) only in the E group. Conclusion: Intention to treat group comparisons indicated that at the mean dose taken, enrichment with n-3 fatty acids did not provide a therapeutic advantage and that both supplements were equally effective in arresting weight loss. Post hoc dose-response analysis suggests that if taken in sufficient quantity, only the n-3 fatty acid enriched energy and protein dense supplement results in net gain of weight, lean tissue, and improved quality of life. Further trials are required to examine the potential role of n-3 enriched supplements in the treatment of cancer cachexia.

Weight loss strategies, stress, and cognitive function:supervised versus unsupervised dieting

The early stages of dieting to lose weight have been associated with neuro-psychological impairments. Previous work has not elucidated whether these impairments are a function solely of unsupported or supported dieting. Raised cortico-steroid levels have been implicated as a possible causal mechanism. Healthy, overweight, pre-menopausal women were randomised to one of three conditions in which they dieted either as part of a commercially available weight loss group, dieted without any group support or acted as non-dieting controls for 8 weeks. Testing occurred at baseline and at 1, 4 and 8 weeks post baseline. During each session, participants completed measures of simple reaction time, motor speed, vigilance, immediate verbal recall, visuo-spatial processing and (at Week 1 only) executive function. Cortisol levels were gathered at the beginning and 30 min into each test session, via saliva samples. Also, food intake was self-recorded prior to each session and fasting body weight and percentage body fat were measured at each session. Participants in the unsupported diet condition displayed poorer vigilance performance (p=0.001) and impaired executive planning function (p=0.013) (along with a marginally significant trend for poorer visual recall (p=0.089)) after 1 week of dieting. No such impairments were observed in the other two groups. In addition, the unsupported dieters experienced a significant rise in salivary cortisol levels after 1 week of dieting (p<0.001). Both dieting groups lost roughly the same amount of body mass (p=0.011) over the course of the 8 weeks of dieting, although only the unsupported dieters experienced a significant drop in percentage body fat over the course of dieting (p=0.016). The precise causal nature of the relationship between stress, cortisol, unsupported dieting and cognitive function is, however, uncertain and should be the focus of further research. © 2005 Elsevier Ltd. All rights reserved.

The effects of yoked prisms on body posture and egocentric perception in a normal population

The principal theme of this thesis is the effect of yoked prisms on body posture and egocentric perception. Yoked prisms have been clinically used in the management of a variety of visual and neuro-motor dysfunctions. Most studies have been conducted in pathological populations by studying the effects of prismatic adaptation, without distinguishing short and long term effects. In this study, postural and perceptual prismatic effects have been studied by preventing prism adaptation. A healthy population was selected in order to investigate the immediate prismatic effects, when there is no obvious benefit from their use for the individual. Posturography was used to assess changes in weight distribution and shifts in centre of pressure (barycentre). In addition, photographic analyses were used to assess effects on posture on the x and z axis. Experiments with space board and visual midline shift were used for the evaluation of spatial perception and egocentric localisation. One pair of 8 Δ yoked prisms base left (BL) and one pair of 8 Δ yoked prisms base up (BU) were applied randomly and compared to a pair of plano lenses. Results suggest that immediate prismatic effects take place on a perceptual level and are reflected on an altered body posture respectively without significant changes in weight distribution. Yoked prisms BL showed a rightward rotational effect on spatial perception by expanding space on the z axis when viewing through the base of the prism and constricting space through the apex of the prism. Body posture responded respectively to what was visually perceived by altering posture. A rightward shift and tilt of the head was recorded along with the hips shift and shoulders tilt in the dame direction. Additionally, right shoulder shifted backwards and an angular midline shift to the right was recorded. The egocentric localisation was affected by shifting the midline perception to the left. Yoked prisms BU resulted on a head shift forward and a reduction of the head-neck angle by bringing the chin closer to the chest. The egocentric localisation was altered on the vertical axis providing subjects the perception that their eye level was higher during the experiment. In conclusion, yoked prisms seemed to induce changes in body posture, mainly in the upper body and head, without any significant changes in weight distribution. These changes are partially reflected in spatial perception tests and egocentric localisation before any prismatic adaptation takes place.

Resting energy expenditure, macronutrient utilization, and body composition in term infants after corrective surgery of major congenital anomalies: a case-study

Introduction - Knowledge on the metabolic changes and nutritional needs during the postsurgical anabolic phase in infants is scarce. This analysis explores the associations of resting energy expenditure (REE) and macronutrient utilization with body composition of full-term infants, during catch-up growth after corrective surgery of major congenital anomalies. Methods - A cohort of full-term appropriate for-gestational-age neonates subjected to corrective surgery of major congenital anomalies were recruited after gaining weight for at least one week. REE and macronutrient utilization, measured by respiratory quotient (RQ), were assessed by indirect calorimetry using the Deltatrac II Metabolic Monitor ®. Body composition, expressed as fat-free mass (FFM), fat mass (FM) and adiposity defined as percentage of FM (% FM), was measured by air displacement plethysmography using the Pea Pod ®. Results - Four infants were included at 3 to 5 postnatal weeks. Recommended energy and macronutrient intakes for healthy term infants were provided. Through the study, the median (min-max) REE (Kcal/Kg FFM/d) was 70.8 (60.6-96.1) and RQ was 0.99 (0.72-1.20). Steady increases in both body weight and FFM were associated with initial decrease in FM and adiposity followed by their increase. Low RQ preceded decrease in adiposity. Conclusion - The marked adiposity depletion, not expected during steady weight gain in the postsurgical period, prompts us to report this finding. The subsequent adiposity catch-up was associated with relatively high REE and RQ, suggesting preferential oxidation of carbohydrates and preservation of lipids for fat storage.

Self-perceived weight status, dieting and unhealthy weight-control behaviors among Spanish male adolescents

Introduction: Self-perceived weight status among adolescents has been associated with weight-control behaviors. However, this relationship varies across weight status. Objectives: The aim of this study was to examine the effect of self-perceived weight status on dieting and unhealthy weight-control behaviors among Spanish male adolescents, across weight status. Method: Participants were 597 Spanish male adolescents (M = 13.94 years old, SD = 0.60). Body weight and height were measured in situ. Self-perceived weight status, dieting, and unhealthy weight-control behaviors were evaluated. Results: The adolescents were inaccurate on estimating their weight status. Those who were overweight or obese, or who perceived themselves to be so, were more likely to report dieting and unhealthy weight-control behaviors. Discussion: There is a need to promote healthier eating behaviors among adolescents, and to take into account the fact that self-perceived weight status may hinder the adoption of such behaviors.

Assessments of body composition and bone parameters of lactating rats treated with diet containing flaxseed meal (Linum usitatissinum) during post-weaning period

Introduction: There are few studies on body composition and the effects of diet on weight postpartum women. The aim was to evaluate the body composition and bone parameters in lactating rats treated with diet containing flaxseed flour during postweaning period. Methods: After weaning, the lactating rat were divided in control (n = 6) and experimental (F, n = 6) group, treated with 25% flaxseed flour diet. After 30 days, body composition by dual-energy X-ray absorptiometry, serum analysis, organs and intra-abdominal fat mass, femur and lumbar vertebra parameters were determined. Results: The groups showed similar food intake, body mass and bone parameters. While F group showed the following: lower body (-5%), gonadal (-17%), mesenteric (-23%) and intra-abdominal (-6%) fat mass. Increase of HDL-cholesterol (+10%) and lower glucose (-15%), triglycerides (P < 0.05, -37%) and cholesterol (P < 0.05, -21%). Conclusions: The findings highlight the effects of flaxseed for control of adiposity and to maintain a healthy biochemical profile during the postnatal period.

ASSOCIATION OF BIRTH WEIGHT AND TIME OF BREASTFEEDING WITH CURRENT NUTRITIONAL STATUS OF CHILDREN

Objetivo: Analisar a relação entre o peso ao nascer (PN) e o tempo de aleitamento materno (AM) com o atual estado nutricional de crianças de dois a seis anos de idade. Métodos: Estudo observacional, quantitativo e do tipo transversal, realizado com crianças, independentemente do sexo, com idades entre dois a seis anos, matriculadas em sete escolas de educação infantil da rede municipal de um município do interior do Rio Grande do Sul (RS), no período de junho a agosto de 2014. Participaram 353 crianças, aferindo-se peso e altura, após os pais terem respondido a um questionário de Peso ao Nascer (PN) e tempo de aleitamento materno. Resultados: A média de aleitamento materno exclusivo foi de 3,47 ± 2,81 meses. A maioria das crianças (50,7%, n=179) encontrou-se em risco de sobrepeso ou sobrepeso para a idade, conforme o Índice de Massa Corporal (IMC). O PN apresentou correlação positiva com a altura atual (r=0,164, p=0,002) e com o peso atual (r=0,180, p=0,001). O PN foi significativamente maior entre os meninos (p=0,003), e o tempo de AM associado à alimentação complementar foi significativamente maior entre as meninas (p=0,024). Conclusão: Os resultados sugerem que o peso ao nascer influencia o ganho de peso nos seis primeiros anos de vida, com maior destaque para os meninos; e o tempo de amamentação associado à alimentação complementar foi maior entre as meninas.

Biometry and body chemical eomfosition of some Japanese and Eufopean fish gpecles in culture

Dissertação de mest. em Aquacultura, Unidade de Ciências e Tecnologias dos Recursos Aquáticos, Univ. do Algarve, 1997

Reproductive performance as affected by lactation status and body fat in beef cows.

Seventy-one mature Brangus cows, 38 nonlactating (NL) and 33 in late stage of lactation (L) were fed for 192 days (Phase I) a low energy diet (L). During Phase II (65 days) 19 NL and 17 L cows were fed a high energy diet (H). The other nonlactating (19) and lactating (16) cows remained on the low energy diet. Energy restriction during Phase I did not affect (P> 0.05) cyclic ovarian activity although losses in body weight and condition were substantial. Rapid changes in body weight, condition, and percent empty body lipe (EBLP) during Phase II did not substantially influencefertility, although a five-fold difference in EBLP was observed (NL0H vs. L-L). Treatment groups did not differ (P> 0.05) in conception rate, days from the beginning of the breeding season to breeding and to conception, conception at first service, and number of services per conception. Values observed for these parameters for NL-H, L-H, NL-L, and L-L groups were respectively: 68,4%, `3,.2, 23.3, 36.8% and 1.68; 82,4% 12.7, 19.5, 58.8% and 1.29; 68.4%, 10.2, 17.4, 47.4%, and 1.41; 68.8%, 12.4, 19.5, 43.7%, and 1.50.

Growth and body nutrient deposition of two broiler commercial genetic lines

The objective of this work was to study growth and body nutrient deposition profiles of male and female Cobb and Ross broilers using Gompertz equations. A total number of 1,920 one- to 56-day-old broilers were used. A randomized experimental design in a factorial arrangement (2 strains x 2 sex), with 4 replicates of 120 birds each, was applied. Diets were formulated to supply the nutrient requirements recommended by the genetic companies. A sample of birds was weekly weighed and sacrificed after 24 hours fasting. Carcasses were de-feathered and weighed again. The parameters of the Gompertz equation for body weight and its components (water, ashes, protein, and fat) were estimated. An interaction (p<0.05) between sex and breed was observed for mature weight (Wm) (kg), growth rate (b) (daily) and time at maximum growth rate (t*) (day) of body weight, and body water and ash. Cobb was presented earlier growth and body protein and ash deposition. Ross strain was superior in body water deposition.

Short-term secular change in height, body mass and Tanner-Whitehouse 3 skeletal maturity of Madeira youth, Portugal

Secular trends in height and weight are reasonably well documented in Europe. Corresponding observations for skeletal maturation are lacking. Aim: To assess secular trends in height, body mass and skeletal maturity of Portuguese children and adolescents and to provide updated reference values for skeletal maturity scores (SMSs). Subjects and methods: Data for 2856 children and adolescents of 4–17 years, 1412 boys and 1444 girls, from The ‘Madeira Growth Study’ (MGS; 1996–1998) and from the‘Healthy Growth of Madeira Children Study’ (CRES; 2006) were used. Height and body mass were measured. Skeletal maturity was assessed with the Tanner-Whitehouse 2 and 3 methods. Results: Children from CRES were taller and heavier than peers from MGS. Differences in height reached 5.8cm in boys and 5.5cm in girls. RUS SMSs did not differ consistently between surveys boys, while higher RUS scores were observed in CRES girls. Adult RUS SMSs for MGS and CRES combined were attained at 15.8 years in boys and 14.8 years in girls. Corresponding ages for adult Carpal SMSs were 14.4 and 14.0, respectively. Conclusion: The short-term trends for height and mass were not entirely consistent with the trends in RUS and Carpal SMSs and SAs.

Short-term secular change in height, body mass and Tanner-Whitehouse 3 skeletal maturity of Madeira youth, Portugal

Secular trends in height and weight are reasonably well documented in Europe. Corresponding observations for skeletal maturation are lacking. Aim: To assess secular trends in height, body mass and skeletal maturity of Portuguese children and adolescents and to provide updated reference values for skeletal maturity scores (SMSs). Subjects and methods: Data for 2856 children and adolescents of 4–17 years, 1412 boys and 1444 girls, from The ‘Madeira Growth Study’ (MGS; 1996–1998) and from the‘Healthy Growth of Madeira Children Study’ (CRES; 2006) were used. Height and body mass were measured. Skeletal maturity was assessed with the Tanner-Whitehouse 2 and 3 methods. Results: Children from CRES were taller and heavier than peers from MGS. Differences in height reached 5.8cm in boys and 5.5cm in girls. RUS SMSs did not differ consistently between surveys boys, while higher RUS scores were observed in CRES girls. Adult RUS SMSs for MGS and CRES combined were attained at 15.8 years in boys and 14.8 years in girls. Corresponding ages for adult Carpal SMSs were 14.4 and 14.0, respectively. Conclusion: The short-term trends for height and mass were not entirely consistent with the trends in RUS and Carpal SMSs and SAs.

Phytate-phosphorus and phytase contents on the relative weight of organs, intestinal morphometry and performance of broilers.

ABSTRACT: In order to evaluate the efficiency of phytase in diets with low and high phytate phosphorus (PP) content, as a consequence of wheat bran inclusion, on the relative weight of organs, intestinal morphometry and performance, three hundred and eighty-four male Cobb500 broilers were housed in metabolic cages. Animals were assigned into four treatments in a 2x2 factorial scheme in a randomized block design with eight replicates of 12 birds each. From 11 days of age birds received experimental diets, which consisted of: Diet low in PP; Diet low in PP with phytase (500FTU kg-1); Diet with a high PP and Diet with a high PP with phytase (500FTU kg-1). At 22 and 32 days of age two birds were slaughtered in order to collect gizzard, heart, liver, cecum, cloacal bursa, and at 32 days, a portion of the duodenum, jejunum and ileum was collected for morphometric evaluation. From 22 to 32 days of age average feed intake, average weight gain, average body weight and feed conversion ratio were also evaluated. Data were subjected to analysis of variance, fixed effects of diet and phytase and interaction between factors as well as the random block effects were tested. There was no significant interaction for the variables studied, concluding that phytase in diets with low or high phytate phosphorus content did not change the relative weight of organs, intestinal morphometrics and performance; only isolated effects were observed. RESUMO: Para avaliar a eficiência da fitase em dietas com baixo e alto teor de fósforo fítico (PP), em função da inclusão ou não do farelo de trigo, sobre o peso relativo de órgãos, morfometria intestinal e desempenho, foram alojados 384 frangos de corte, machos da linhagem Cobb500, em gaiolas metabólicas. Os animais foram distribuídos em quatro tratamentos em um arranjo fatorial 2x2 em delineamento de blocos casualizados com oito repetições e 12 aves por unidade experimental (UE). A partir de 11 dias de idade as aves receberam as dietas experimentais, que consistiram em: Dieta com baixo teor de PP; Dieta com baixo teor de PP com fitase (500FTU kg-1); Dieta com alto teor de PP e Dieta com alto teor de PP com fitase (500FTU kg-1). Aos 22 e 32 dias de idade foram abatidas duas aves por UE para coletar a moela, coração, fígado, ceco, bolsa cloacal, e aos 32 dias foi coletada uma porção do duodeno, jejuno e íleo para avaliação da morfometria. No período de 22 a 32 dias de idade foram avaliados o consumo médio de ração, ganho de peso médio, peso médio corporal e a conversão alimentar. Os dados foram submetidos à análise de variância, onde foram testados os efeitos fixos de dieta e fitase e a interação entre os fatores, bem como o efeito aleatório de bloco. Não foi observada interação significativa para nenhuma das variáveis estudadas, concluindo-se que a fitase em dietas com baixo ou alto de PP não altera o peso relativo dos órgãos, a morfometria intestinal e o desempenho, apenas efeitos isolados foram observados.