bluuebunny/crossref_metadata_2025 huggingface dataset:
Melatonin ameliorates hippocampal nitric oxide production and large conductance calcium‐activated potassium channel activity in chronic intermittent hypoxia
Authors: Tjong Y. W. , Li M. F. , Hung M. W. , Fung M. L.
Published: October 2007

Abstract:  Melatonin protects against hippocampal injury induced by intermittent hypoxia (IH). IH‐induced oxidative stress is associated with decreases in constitutive production of nitric oxide (NO) and in the activity of large conductance calcium‐activated potassium (BK) channels in hippocampal neurons. We tested the hypothesis that administration of melatonin alleviates the NO deficit and impaired BK channel activity in the hippocampus of IH rats. Sprague–Dawley rats were injected with melatonin (10 mg/kg, i.p.) or vehicle before daily IH exposure for 8 hr for 7 days. The NO and intracellular calcium ([Ca2+]i) levels in the CA1 region of hippocampal slices were measured by electrochemical microsenor and spectrofluorometry, respectively. The activity of BK channels was recorded by patch‐clamping electrophysiology in dissociated CA1 neurons. Malondialdehyde levels were increased in the hippocampus of hypoxic rats and were lowered by the melatonin treatment. Levels of NO under resting and hypoxic conditions, and the protein expression of neuronal NO synthase (nNOS) were significantly reduced in the CA1 neurons of hypoxic animals compared with the normoxic controls. These deficits were mitigated in the melatonin‐treated hypoxic rats with an improved [Ca2+]i response to acute hypoxia. The open probability of BK channels was decreased in the hypoxic rats and was partially restored in the melatonin‐treated animals, without alterations in the expression of channel subunits and unitary conductance. Acute treatment of melatonin had no significant effects on the BK channel activity or on the [Ca2+]i response to hypoxia. Collectively, these results suggest that melatonin ameliorates the constitutive NO production and BK channel activity via an antioxidant mechanism against an IH‐induced down‐regulation of nNOS expression in hippocampal neurons.
Health‐related quality of life and intellectual functioning in children in remission from acute lymphoblastic leukaemia
Authors: Reinfjell Trude , Lofstad G Elisabeth , Veenstra Marijke , Vikan Arne , Diseth Trond H
Published: October 2007

Aim: To evaluate the health‐related quality of life (HRQOL) and intellectual functioning of children in remission from acute lymphoblastic leukaemia (ALL).

Methods: Children and adolescents treated for ALL (n = 40; mean age 11.8 years, range 8.5–15.4) and healthy controls (n = 42; mean age 11.8, range 8.11–15.0) were assessed through a cross‐sectional approach using the Pediatric Quality of Life inventory (PedsQL™) 4.0 and the Wechsler Intelligent Scale for children‐III (WISC‐III).

Results: Children and adolescents treated for ALL reported on average significantly lower HRQOL compared to healthy controls: the mother's proxy‐report showed significantly lower HRQOL for their children, as did the father's proxy‐report, measured by the PedsQL™ 4.0 Total Scale and Psychosocial Health Scale. Intellectual functioning as measured by the WISC‐III Full Scale IQ was below that of the control group, but still within the normal range.

Conclusions: Significant differences found between children treated for ALL and their control group for the PedsQL Psychosocial Health Scale may indicate that the complex illness‐treatment experience can make children more vulnerable with regard to psychosocial sequels, in spite of otherwise satisfactory physical and intellectual functioning. Follow‐up programs that target the psychosocial health of children in remission from ALL should be implemented.
Isolated extraordinary daytime urinary frequency of childhood: a case series of 26 children in Switzerland
Authors: Corigliano Teresa , Renella Raffaele , Robbiani Anna , Riavis Mauro , Bianchetti Mario G
Published: October 2007

Background: The term ‘isolated extraordinary daytime urinary frequency’ designates an abnormally increased diurnal frequency of painless urination in a completely toilet‐trained child with normal urinalysis.

Methods: We report the history of 26 children (16 boys and 10 girls; aged between 4.1 and 10 years) who were referred to us between 2002 and 2006 and subsequently diagnosed with this condition.

Results: Possible psychosocial problems, or recent emotional stressors, were disclosed in the majority of the children: recent (36 months or less) asylum seekers (n = 9), school‐related problems (n = 4), parental divorce (n = 2) or death of the mother (n = 1). Possible dietary causes were observed in 9 patients: oxalate‐rich beverages (n = 5) and liberal ingestion of ‘acidic’ juices (n = 4). A diet low in oxalates was recommended when children were consuming large quantities of oxalate‐rich beverages; and a diet low in acidic juice was recommended in those liberally ingesting acidic juices. Reassurance and observation were the approach in the remaining cases. The median duration of the symptoms was 5 months. A longer (p < 0.05) duration was noted in children of asylum seekers.

Conclusions: This functional condition is easily identifiable, but often under‐ or misdiagnosed. Confounding the condition might result in redundant investigation.
Risk factors in childhood obesity—findings from the All Babies In Southeast Sweden (ABIS) cohort
Authors: Huus Karina , Ludvigsson Jonas F , Enskär Karin , Ludvigsson Johnny
Published: October 2007

Aim: Our objective was to investigate whether overweight at a very young age predicts overweight at 5 years and to identify risk factors for overweight/obesity at 5 years, thereby making it easier for Child Health Services to focus their prevention strategies on risk groups.

Methods: We analysed data from the ABIS study (All Babies In Southeast Sweden), a prospective cohort study. Parents answered questionnaires between childbirth (n = 16,058) and 5 years (n = 7356).

Results: High body mass index (BMI; >95th percentile) at 1 year (adjusted odds ratio [AOR]= 6.57; 95% CI = 4.63–9.33; p < 0.001) and age‐adjusted BMI > 25 at 2.5 years (AOR = 14.24; 95% CI = 10.52–19.29; p < 0.001) were associated with increased risk of obesity (age‐adjusted BMI > 30) at 5 years. Heredity for type 2 diabetes (p = 0.022), high parental BMI and the child's own BMI at birth and at 1 year predicted higher BMI of the child at 5 years (p < 0.001). High parental education was inversely associated with child overweight (p = 0.054 respective p < 0.005).

Conclusion: Obesity at age 1 and at 2.5 years predicts obesity at 5 years. Obese parents, especially in families with heredity for type 2 diabetes and low education, should be targeted in early obesity prevention strategies by the Child Health Service.
Oestrogen receptors and linear bone growth
Authors: Chagin Andrei S. , Sävendahl Lars
Published: October 2007

In this review we summarize available data regarding linear growth in oestrogen receptor alpha (ERα)‐ and oestrogen receptor beta (ERβ)‐deficient mice. We discuss these findings in relation to known oestrogenic effects in humans and the possibility of applying this knowledge for the therapeutic modulation of longitudinal bone growth employing selective oestrogen receptor modulators (SERMs). We conclude that SERMs potentially could offer new possibilities to modulate bone growth by specifically targeting different oestrogen receptors within the growth plate.
Association of n‐6 long‐chain polyunsaturated fatty acids to −866 G/A genotypes of the human uncoupling protein 2 gene in obese children
Authors: Bokor Szilvia , Csernus Katalin , Erhardt Éva , Burus István , Molnár Dénes , Decsi Tamás
Published: October 2007

Aim: To investigate the association of plasma fatty acids with the −866 G/A polymorphism of uncoupling protein 2 (UCP2) in obese children.

Methods: Fatty acid composition of plasma phospholipids and sterol esters were investigated in 80 obese children.

Results: Values of dihomo‐γ‐linolenic acid (C20:3n‐6) were significantly lower in children with the −866 A/A (n = 12) than in those with the −866 G/A (n = 34) or −866 G/G (n = 34) genotype in plasma phospholipids (3.01 [0.42] vs. 3.56 [1.02] vs. 3.53 [0.84], % weight/weight, median [interquartile range], p < 0.05), and were significantly lower in children with the −866 A/A genotype than in the other two groups in plasma sterol esters (0.73 [0.22] vs. 0.92 [0.23] vs. 0.94 [0.25], p < 0.05). Phospholipid C20:3n‐6 and arachidonic acid (C20:4n‐6) values showed only in children with the −866 G/G and −866 G/A genotypes significant positive correlations with plasma insulin concentrations.

Conclusions: Significantly lower values of C20:3n‐6 can be detected in obese children with the homozygous (−866 A/A) mutation of UCP2 than in equally obese children with heterozygous mutation or the normal genotype. High glucose‐stimulated insulin response is associated with high plasma C20:3n‐6 and C20:4n‐6 values only in obese children with the G allele of the −866 G/A polymorphism.
Collagenous colitis and eosinophilic gastritis in a 4‐year old girl: a case report and review of the literature
Authors: Benchimol Eric I , Kirsch Richard , Viero Sandra , Griffiths Anne M
Published: October 2007

Collagenous colitis (CC), a form of microscopic colitis, is characterized by a thick subepithelial collagen layer in the colon in the presence of chronic nonbloody watery diarrhoea and macroscopically normal‐appearing colonic mucosa. Typically affecting elderly adults, CC is rare in children with only 12 cases previously reported in the literature. We report the case of a 4‐year‐old girl with CC associated with eosinophilic gastritis, which was clinically responsive to treatment with ketotifen, a benzocycloheptathiophene derivative, and H1 class of antihistamine that stabilizes mast cells and potentially impairs eosinophil migration to target organs. We review the published cases of paediatric‐onset CC and summarize the links between eosinophils and CC in the clinical and basic science literature.

Conclusion: CC is a rare cause of chronic diarrhoea in children and may relate to mast cell and eosinophil activity.
Effect of physical activity intervention on body composition in young children: influence of body mass index status and gender
Authors: Lazaar Nordine , Aucouturier Julien , Ratel Sébastien , Rance Mélanie , Meyer Martine , Duché Pascale
Published: October 2007

Aim: To fight overweight and obesity in childhood, this study proposes an additional physical activity (PA) in young children aged 6–10 years. The objective was to evaluate the effect of school‐based PA on the body composition according to body mass index (BMI) categories (nonobese vs. obese) and gender.

Methods: This 6‐month study examined the effect of this intervention on body composition in 425 children in 14 primary schools (2 weekly PA sessions of 1 h each) compared to 5 control schools. Adiposity indices were evaluated or calculated: BMI, BMI z‐score, waist circumference, sum of skinfolds and fat‐free mass.

Results: No difference in the prevalence of obesity and anthropometric characteristics was found between the intervention and control groups at baseline. In girls, PA intervention had significant effect on all anthropometric variables (p < 0.05 to p < 0.001), except on BMI. In contrast, in boys only BMI z‐score (p < 0.001) and fat‐free mass (p < 0.001) were affected.

Conclusions: Six months of preventive PA intervention offer an effective means to improve body composition in obese children. The pattern of response related to PA was similar between girls and boys. In contrast, the pattern was different according to BMI category, with a higher response in obese than nonobese children.
Focus on infantile colic
Authors: Savino Francesco
Published: October 2007

Infantile colic is a widespread clinical condition in the first 3 months of life, which is easily recognized, but incompletely understood and difficult to solve. The available evidence suggests that infantile colic might have several independent causes. The medical hypotheses include food hypersensitivity or allergy, immaturity of gut function and dysmotility, and the behavioural hypotheses include inadequate maternal–infant interaction, anxiety in the mother and difficult infant temperament. Other recent hypotheses, such as hormone alterations and maternal smoking, still need confirmation, whereas the new concept of alterations in the gut microflora, have been reported. A number of interventions, including pharmacological agents, are discussed, but it is probable that infants with colic require a graded strategy.

Conclusion: Considering the favourable clinical course and the wide range of manifestations, a safe approach should be adopted, which is proportional to the intensity of the infantile colic. However, further research and guidelines are still needed.
Environmental risk factors for attention‐deficit hyperactivity disorder
Authors: Banerjee Tania Das , Middleton Frank , Faraone Stephen V.
Published: October 2007

Attention‐deficit hyperactivity disorder (ADHD) is the most common cognitive and behavioural disorder diagnosed among school children. It is characterized by deficient attention and problem solving, along with hyperactivity and difficulty withholding incorrect responses. This highly prevalent disorder is estimated to affect 5–10% of children and in many cases, persists into adulthood,leading to 4% prevalence among adults. Converging evidence from epidemiologic, neuropsychology, neuroimaging, genetic and treatment studies shows that ADHD is a valid medical disorder.

The majority of studies performed to assess genetic risk factors in ADHD have supported a strong familial nature of this disorder. Family studies have identified a 2‐ to 8‐fold increase in the risk for ADHD in parents and siblings of children with ADHD. Various twin and adoption studies have also highlighted the highly genetic nature of ADHD. In fact the mean heritability of ADHD was shown to be 0.77, which is comparable to other neuropsychiatric disorders such as schizophrenia or bipolar disorder.

However, several biological and environmental factors have also been proposed as risk factors for ADHD, including food additives/diet, lead contamination, cigarette and alcohol exposure, maternal smoking during pregnancy, and low birth weight. Many recent studies have specifically examined the relationships between ADHD and these extraneous factors. This review describes some of these possible risk factors.

Conclusion: Although a substantial fraction of the aetiology of ADHD is due to genes, the studies reviewed in this article show that many environmental risk factors and potential gene–environment interactions also increase the risk for the disorder.
A different view: there is value in grading intraventricular hemorrhage
Authors: Whitelaw Andrew
Published: October 2007

The traditional 1–4 grading system for intra‐ventricular haemorrhage (IVH) has been criticized on several points. Grade 1 IVH is not really intra‐ventricular at all but all neurosonographers have recognized this for many years. Grade 3 IVH is criticized as it includes ventricular dilatation but grade 3 IVH is a haemorrhage large enough to distend the ventricle with blood not cerebrospinal fluid (CSF). The distinction between small and large IVH is valuable as the prognosis is very different. Grade 4 IVH is criticized as it is not an ‘extension’ but authors have described this as parenchymal haemorrhagic infarction for decades. Grade 4 IVH has different risk factors, prognosis and prophylaxis from periventricular leucomalacia. The shorthand category of ‘severe IVH’, meaning grades 3 and 4, is not adequate for individual patient assessment but is certainly useful for annual statistics, comparisons over time and between hospitals.

Conclusion: Despite limitations, grading IVH has value.
Association of adiposity measures with blood lipids and blood pressure in children aged 8–11 years
Authors: Martínez Vizcaíno Vicente , Salcedo Aguilar Fernando , Solera Martínez Montserrat , Sánchez López Mairena , Franquelo Gutiérrez Ricardo , Rodríguez‐Artalejo Fernando
Published: October 2007

Aim: To examine the association of body mass index (BMI), triceps skinfold thickness (TST) and percentage body fat (%BF) from bioelectrical impedance analysis (BIA) with blood lipids, systolic blood pressure (SBP) and diastolic blood pressure (DBP) in children.

Methods: Cross‐sectional study was conducted on 1280 schoolchildren aged 8–11 years from the Cuenca province (Spain). Data collection was conducted under standardized conditions, taking several measurements of each variable to enhance accuracy. Analyses were performed using age‐adjusted correlation coefficients, and multiple linear regression adjusted for age, BMI, TST and %BF.

Results: Correlations between %BF and apolipoprotein (apo) B, total cholesterol, low‐density lipoprotein cholesterol (LDL‐c), total cholesterol/HDL‐c ratio and DBP were higher than those for BMI and TST. In contrast, the correlations between BMI, and apo A‐I and SBP were higher than those for %BF and TST. The results were similar across the sexes. The correlations between each of the three measures of body fatness, and blood lipids and blood pressure were highest in children with greatest BMI and %BF. When analyses were adjusted for the three body fatness measures, %BF showed stronger associations than did BMI or TST with blood lipids and blood pressure, with the exception of apo A‐I and SBP, which were more closely associated with BMI.

Conclusion: %BF from BIA is more strongly associated than either BMI or TST with most of the blood lipid fractions in schoolchildren aged 8–11 years.
Improved vitamin A supplementation regimen for breastfed very low birth weight infants
Authors: Aurvåg Anne K , Henriksen Christine , Drevon Christian A , Iversen Per O , Nakstad Britt
Published: October 2007

Objective: Preterm infants usually have low retinol status at birth and at discharge from hospital. We have evaluated a new protocol designed to improve plasma retinol in very low birth weight infants (VLBW, birth weight < 1500 g).

Design: An open intervention trial was conducted in which vitamin A was given in a human milk fortifier. The daily dose of vitamin A varied according to bodyweight and was given mixed with human milk instead of as a bolus. Blood samples were collected at inclusion and at discharge from hospital. Plasma was analyzed for retinol using high‐performance liquid chromatography. The daily intake of vitamin A and plasma retinol concentration was compared with the vitamin protocol normally used in Norwegian hospitals.

Results: Sixty VLBW infants were included and 53 completed the study. At discharge from hospital, the reference group had lower median plasma retinol concentrations compared to the modified group (0.30 μM vs. 0.49 μM, p = 0.008). Fewer infants in the modified group had plasma retinol levels below 0.35 μM (indicating reduced hepatic stores) compared to infants in the reference group (44% vs. 69%, p = 0.04).

Conclusion: The modified protocol improved plasma retinol levels at discharge compared to the reference protocol.
Adhesion Modeling on Rough Low Linear Density Polyethylene
Authors: Meiron T.S. , Saguy I.S.
Published: October 2007

ABSTRACT:  Food adhesion is an important attribute that could have both positive and negative ramifications depending on the application. Yet, its quantification remains cumbersome and as a consequence adhesion models are scarce. The effect of surface roughness, free energy, and ozone treatment on adhesion of rough low linear density polyethylene films was investigated. Adhesion was measured by a 180° peel strength test. The plastic films were roughened (surface roughness ratio, r, ranged from 1.00 to 1.15). Exposing the film to ozone treatment (0 to 300 s) modified its surface free energy, γs (32.4 to 37.9 mJ/m2, respectively), and its polar component of the surface free energy, γps (3.0 to 8.3 mJ/m2, respectively). The films were coated with polyurethane capable of forming hydrogen bonds. Adhesion was found to be a function of the apparent contact angle of water, θap[water], surface roughness ratio, and surface free energy. The linear relationship between the apparent contact angle of water, θap[water], and γps was incorporated in building an empirical model that quantifies peel strength as function of r and γps. The model showed good agreement with experimental data, especially for longer ozone exposures and rougher surfaces. The empirical model provides insight into the relationships between surface roughness, surface energy, and adhesion. Quantifying these effects could facilitate reducing biofilm forming on food equipment, antisticking treatments, or easy peel packages, or reducing food residues adhering to the food packages and consequently minimize oxidation, off flavors, and waste.
Electrical Conductivity and Physical Properties of Surimi–Potato Starch under Ohmic Heating
Authors: Pongviratchai P. , Park J.W.
Published: October 2007

ABSTRACT:  Electrical conductivities of Alaska pollock surimi mixed with native and pregelled potato starch at different concentrations (0%, 3%, and 9%) were measured at different moisture contents (75% and 81%) using a multifrequency ohmic heating system. Surimi‐starch paste was tested up to 80 °C at frequencies from 55 Hz to 20 KHz and at alternating currents of 4.3 and 15.5 V/cm voltage gradient. Electrical conductivity increased when moisture content, applied frequency, and applied voltage increased, but decreased when starch concentration increased. Electrical conductivity was correlated linearly with temperature (R2≈ 0.99). Electrical conductivity pattern (magnitude) changed when temperature increased, which was clearly seen after 55 °C in the native potato starch system, especially at high concentration. This confirms that starch gelatinization that occurred during heating affects the electrical conductivity. Whiteness and texture properties decreased with an increase of starch concentration and a decrease of moisture content.
Identification of Poultry Meat‐Derived Fatty Acids Functioning as Quorum Sensing Signal Inhibitors to Autoinducer‐2 (AI‐2)
Authors: Widmer K.W. , Soni K. A. , Hume M.E. , Beier R.C. , Jesudhasan P. , Pillai S.D.
Published: October 2007

ABSTRACT:  Autoinducer‐2 (AI‐2) is a compound that plays a key role in bacterial cell‐to‐cell communication (quorum sensing). Previous research has shown certain food matrices inhibit this signaling compound. Using the reporter strain, Vibrio harveyi BB170, quorum‐sensing inhibitors contained in poultry meat wash (PMW) samples were characterized by molecular weight and hydrophobic properties using liquid chromatography systems. Most fractions that demonstrated AI‐2 inhibition were 13.7 kDa or less, and had hydrophobic properties. Hexane was used to extract inhibitory compounds from a PMW preparation and the extract was further separated by gas chromatography (GC). Several fatty acids were identified and quantified. Linoleic acid, oleic acid, palmitic acid, and stearic acid were each tested for inhibition at 0.1, 1, and 10 mM concentrations. All samples expressed AI‐2 inhibition (ranging from approximately 25% to 99%). Fatty acids, combined in concentrations equivalent to those determined by GC analysis, expressed inhibition at 59.5%, but higher combined concentrations (10‐ and 100‐fold) had inhibition at 84.4% and 69.5%, respectively. The combined fatty acids (100‐fold) did not demonstrate a substantial decrease in colony plate counts, despite presenting high AI‐2 inhibition. These fatty acids, through modulating quorum sensing by inhibition, may offer a unique means to control foodborne pathogens and reduce microbial spoilage.
Heat Transfer Models for Predicting Salmonella enteritidis in Shell Eggs Through Supply Chain Distribution
Authors: Almonacid S. , Simpson R. , Teixeira A.
Published: October 2007

ABSTRACT:  Egg and egg preparations are important vehicles for Salmonella enteritidis infections. The influence of time–temperature becomes important when the presence of this organism is found in commercial shell eggs. A computer‐aided mathematical model was validated to estimate surface and interior temperature of shell eggs under variable ambient and refrigerated storage temperature. A risk assessment of S. enteritidis based on the use of this model, coupled with S. enteritidis kinetics, has already been reported in a companion paper published earlier in JFS. The model considered the actual geometry and composition of shell eggs and was solved by numerical techniques (finite differences and finite elements). Parameters of interest such as local (h) and global (U) heat transfer coefficient, thermal conductivity, and apparent volumetric specific heat were estimated by an inverse procedure from experimental temperature measurement. In order to assess the error in predicting microbial population growth, theoretical and experimental temperatures were applied to a S. enteritidis growth model taken from the literature. Errors between values of microbial population growth calculated from model predicted compared with experimentally measured temperatures were satisfactorily low: 1.1% and 0.8% for the finite difference and finite element model, respectively.
Lytic Antimicrobial Activity of Hen Egg White Lysozyme Immobilized to Polystyrene Beads
Authors: Wu Y. , Daeschel M.A.
Published: October 2007

ABSTRACT:  Lysozyme [EC 3.2.1.17] was covalently attached to polystyrene resin beads by the sole histidine residue (His‐15) through peptide spacers of various lengths. The spacers were amino acid chains composed of 6‐aminocaproic acid synthesized with the solid phase peptide synthesis method. Immobilized lysozyme with a spacer length of three 6‐aminocaproic acid units (2736 U/g resin with a protein load of 2.21 mg/g resin) displayed the greatest degree of hydrolytic activity against lyophilized Micrococcus lysodeikticus cell wall preparations. Enzymatic activity of immobilized lysozyme was 14.2% of that of the free enzyme. Preparations with longer spacers yielded higher total activity yet the retained activity was constant at about 14% level. A control that consisted of randomly coupled lysozyme to polystyrene beads without an amino acid spacer gave an enzyme activity of 158 U/g with a protein load of 1.24 mg/g resin which equated to 1.4% retained activity. Properties of the immobilized lysozyme system were studied, including stability and activity against soluble compared with insoluble substrates. A kinetics study of the immobilized lysozyme using Eadie–Hofstee plot parameters suggested significant external diffusion effects indicative of deviation from classic Michaelis–Menten kinetic behavior.
Improvement of Stability of Oil‐in‐Water Emulsions Containing Caseinate‐Coated Droplets by Addition of Sodium Alginate
Authors: Pallandre S. , Decker E.A. , McClements D.J.
Published: October 2007

ABSTRACT:  The potential of sodium alginate for improving the stability of emulsions containing caseinate‐coated droplets was investigated. One wt% corn oil‐in‐water emulsions containing anionic caseinate‐coated droplets (0.15 wt% sodium caseinate) and anionic sodium alginate (0 to 1 wt%) were prepared at pH 7. The pH of these emulsions was then adjusted to 3.5, so that the anionic alginate molecules adsorbed to the cationic caseinate‐coated droplets. Extensive droplet aggregation occurred when there was insufficient alginate to completely saturate the droplet surfaces due to bridging flocculation, and when the nonadsorbed alginate concentration was high enough to induce depletion flocculation. Emulsions with relatively small particle sizes could be formed over a range of alginate concentrations (0.1 to 0.4 wt%). The influence of pHs (3 to 7) and sodium chloride (0 to 500 mM) on the properties of primary (0 wt% alginate) and secondary (0.15 wt% alginate) emulsions was studied. Alginate adsorbed to the droplet surfaces at pHs 3, 4, and 5, but not at pHs 6 and 7, due to electrostatic attraction between anionic groups on the alginate and cationic groups on the adsorbed caseinate. Secondary emulsions had better stability than primary emulsions at pH values near caseinate's isoelectric point (pHs 4 and 5). In addition, secondary emulsions were stable up to higher ionic strengths (< 300 mM) than primary emulsions (<50 mM). The controlled electrostatic deposition method utilized in this study could be used to extend the range of application of dairy protein emulsifiers in the food industry.
Yerba Mate Tea (Ilex paraguariensis): A Comprehensive Review on Chemistry, Health Implications, and Technological Considerations
Authors: Heck C.I. , De Mejia E.G.
Published: October 2007

ABSTRACT:  Yerba Mate tea, an infusion made from the leaves of the tree Ilex paraguariensis, is a widely consumed nonalcoholic beverage in South America which is gaining rapid introduction into the world market, either as tea itself or as ingredient in formulated foods or dietary supplements. The indigenous people have used it for centuries as a social and medicinal beverage. Yerba Mate has been shown to be hypocholesterolemic, hepatoprotective, central nervous system stimulant, diuretic, and to benefit the cardiovascular system. It has also been suggested for obesity management. Yerba Mate protects DNA from oxidation and in vitro low‐density lipoprotein lipoperoxidation and has a high antioxidant capacity. It has also been reported that Yerba Mate tea is associated to both the prevention and the cause of some types of cancers. Yerba Mate has gained public attention outside of South America, namely the United States and Europe, and research on this tea has been expanding. This review presents the usage, chemistry, biological activities, health effects, and some technological considerations for processing of Yerba Mate tea. Furthermore, it assesses in a concise and comprehensive way the potential of Ilex paraguariensis as a source of biological compounds for the nutraceutical industry.
Microstructure-Level Model for the Prediction of Tool Failure in Coated WC-Co Cutting Tool Materials During Intermittent Cutting
Authors: Park Sunghyuk , Kapoor Shiv G. , DeVor Richard E.
Published: October 2007

A model to predict failure of coated WC-Co grades due to chipping in intermittent cutting via microstructure-level finite element machining process simulation is presented and applied to various coated WC-Co tools. Coated tools were examined for the characterization and simulation of their microstructures. Model predictions of failure due to chipping for coated WC-Co systems were validated by continuous machining tests. In order to simulate cyclic loading conditions during intermittent cutting, mechanical and thermal boundary conditions were applied during cutting phases and removed during noncutting phases. Interrupted turning experiments were conducted to validate the model, and the results showed that the predictions agreed well with the observations from the experiments. The paper includes the application of this model to a problem of WC-Co grade design.
Kinematic Precision Scaling With Physical Errors in Miniaturization of Four-Bar Polymer Compliant Machines
Authors: Chang R. J. , Wang Y. L.
Published: October 2007

A precision-scaling kinematic model with the effects of physical error is investigated in the miniaturization of four-bar polymer machines with compliant joints. A pseudolinkages model (PLM) for the multiple-links compliant machine is formulated. A scaling formulation of the multiple-links compliant machine and its associated PLM is developed. A method for scaled-up test and scaled-down analysis of the compliant mechanism with the considerations of physical errors of fabrication processes, material properties, and experimental tests is proposed. By defining an index of signal-to-noise ratio, the performance of the miniature realization under physical errors is evaluated. The applications of the scaling PLM for the miniature realization of a compliant machine are illustrated by performing both numerical analysis and experimental testing on four-bar compliant polyethylene machines.
Modeling and Control of a New Robotic Deburring System
Authors: Kim Changhoon , Chung Jae H.
Published: October 2007

This paper discusses the modeling and control of a robotic manipulator with a new deburring tool, which integrates two pneumatic actuators to take advantage of a double cutting action. A coordination control method was developed by decomposing the robotic deburring system into two subsystems: the arm and the deburring tool. A decentralized control approach was pursued in which suitable controllers were designed for the two subsystems in the coordination scheme. Robust feedback linearization was utilized to minimize the undesirable effect of external disturbances, such as static and Coulomb friction and nonlinear compliance of the pneumatic cylinder stemming from the compressibility of air. The developed coordination control method demonstrated its efficacy in terms of deburring accuracy and speed. Simulation results show that the developed robotic deburring system significantly improves the accuracy of the deburring operation.
Toward Magnetorheological Finishing of Magnetic Materials
Authors: Shafrir Shai N. , Lambropoulos John C. , Jacobs Stephen D.
Published: October 2007

Magnetorheological finishing (MRF) is a precision optical finishing process traditionally limited to processing only nonmagnetic materials, e.g., optical glasses, ceramics, polymers, and metals. Here we demonstrate that MRF can be used for material removal from magnetic material surfaces. Our approach is to place an MRF spot on machined surfaces of magnetic WC-Co materials. The resulting surface roughness is comparable to that produced on nonmagnetic materials. This spotting technique may be used to evaluate the depth of subsurface damage, or deformed layer, induced by earlier manufacturing steps, such as grinding and lapping.
On-Line Seam Detection in Rolling Processes Using Snake Projection and Discrete Wavelet Transform
Authors: Li Jing , Shi Jianjun , Chang Tzyy-Shuh
Published: October 2007

This paper describes the development of an on-line quality inspection algorithm for detecting the surface defect “seam” generated in rolling processes. A feature-preserving “snake-projection” method is proposed for dimension reduction by converting the suspicious seam-containing images to one-dimensional sequences. Discrete wavelet transform is then performed on the sequences for feature extraction. Finally, a T2 control chart is established based on the extracted features to distinguish real seams from false positives. The snake-projection method has two parameters that impact the effectiveness of the algorithm. Thus, selection of the parameters is discussed. Implementation of the proposed algorithm shows that it satisfies the speed and accuracy requirements for on-line seam detection.
A Computer-Aided Design Module to Analyze Manufacturing Configurations of Bent and Hydroformed Tubes
Authors: Amici Elisabetta , Campana Francesca , Mancini Edoardo
Published: October 2007

This paper presents a computer-aided design (CAD) module able to analyze different manufacturing configurations of tubes used in mechanical assemblies, such as exhaust system manifolds. It can be included in the knowledge-based expert system category and has been implemented into a CAD platform as a dedicated module able to take into account manufacturing requirements related to tube bending, hydroforming, and cutting. The expert’s knowledge, in terms of set of rules and criteria, has been implemented by means of the automation tools of CATIAV5R10 according to the so-called methodological formal approach. The resulting module is able to join different tubes starting from their geometrical models, obtaining a set of manufacturing alternatives. Each of them is verified with respect to collisions with a bending machine and also in terms of hydroforming process feasibility. Only those solutions that satisfy these checks are accepted as feasible and ranked according to three evaluation criteria related to manufacturing cost and easiness. The system is completely automatic and able to analyze more than 100 different configurations in <10min. The feasible solutions are saved as CAD model to allow FEA of hydroforming and other possible CAE activities. Unfeasible solutions are deleted but reported and documented in a log file. The feasible solution rank is given in a table and has been developed according to a multicriteria approach to make optimal solution detection easier. The proposed test case aims to show and discuss these capabilities. By this module, two or more components of the exhaust system manifold can be manufactured in one stroke as a single component, starting from the same pipe and next trimmed to obtain the desired final parts. This capability can be used to reduce scraps and improve cycle time of the manufacturing process.
The Influence of Gear Hobbing on Worm Gear Characteristics
Authors: Simon Vilmos
Published: October 2007

In this paper, a method is presented for the determination of the differences between the worm gear tooth surface processed by an oversized hob of finite number of teeth or by a flying tool, and the theoretically required gear tooth surface. The influence of hob oversize and machine tool settings on tooth contact pressure and transmission errors is determined. The full geometry and kinematics of gear tooth processing by an oversized hob or by a flying tool is included. The theoretical background is implemented by a computer program. By using this program, the influence of relevant design parameters of the worm gear set and the hob and of machine tool settings on processed gear tooth errors and on loaded tooth contact of the worm gear pair is investigated and discussed.
An Isothermal Finite Difference Model for Droplet Spread in the Spraying of Hot Die Surfaces With Water-Based Graphite Lubricants
Authors: Yang L. , Shivpuri R.
Published: October 2007

Dilute sprays are used in hot die processing to lubricate and cool the die surface prior to forming of the part. These sprays are often stochastic in nature with fine droplets that are randomly deposited at high velocities. Consequently, the spraying mechanism is difficult to measure and to model. This paper presents a simple isothermal deterministic model for the spreading of droplets on hot die surfaces. This model is based on the volume of fluid (VOF) finite difference approach. The lubricant properties for this model are inverse calculated from simple experiments using various lubricant dilution ratios. Using similarity principles, the model is validated by comparing it with results from single droplet experiments with different droplet diameters and deposition speeds. It is found that for dilute suspensions the isothermal assumption is valid for surface temperatures where no-steam forms and that a simple linear relationship exists in the logarithmic scale between the spread factor and the droplet Weber number.
Variation Propagation Analysis on Compliant Assemblies Considering Contact Interaction
Authors: Xie Kang , Wells Lee , Camelio Jaime A. , Youn Byeng D.
Published: October 2007

Dimensional variation is inherent to any manufacturing process. In order to minimize its impact on assembly products it is important to understand how the variation propagates through the assembly process. Unfortunately, manufacturing processes are complex and in many cases highly nonlinear. Traditionally, assembly process modeling has been approached as a linear process. However, many assemblies undergo highly complex nonlinear physical processes, such as compliant deformation, contact interaction, and welding thermal deformation. This paper presents a new variation propagation methodology considering the compliant contact effect, which will be analyzed through nonlinear frictional contact analysis. Its variation prediction will be accurately and efficiently conducted using an enhanced dimension reduction method. A case study is presented to show the applicability of the proposed methodology.
Prediction of Erosion Due to Solid Particle Impact in Single-Phase and Multiphase Flows
Authors: Mazumder Quamrul H.
Published: October 2007

Solid particle erosion of metal surfaces is a major problem in several fluid handling industries due to unpredicted equipment failure and production loss. The prediction of erosion is difficult even in a single-phase flow. The complexity of the problem increases significantly in a multiphase flow due to the existence of different flow patterns where the spatial distribution of the phases changes with the change of phase flow rates. Earlier predictive means of erosion in single and multiphase flows were primarily based on empirical data and were limited to the flow conditions of the experiments. A mechanistic model has been developed for predicting erosion in single-phase and multiphase flows considering the effects of solid particle impact velocities that cause erosion. Local fluid velocities and simplified equations are used to calculate erosion rates assuming a uniform distribution of solid particles in the liquid phase in the multiphase flow. Another assumption was that the solid particle velocities are similar to the velocity of the fluids surrounding the particles. As the model is based on the physics of multiphase flow and erosion phenomenon, it is more general than the previous models. The predicted erosion rates obtained by the mechanistic model are compared to experimental data available in the literature showing a reasonably good agreement.
Evaluation of Turbulence Models for Thermal Striping in a Triple Jet
Authors: Choi Seok-Ki , Kim Seong-O
Published: October 2007

A computational study for an evaluation of the current turbulence models for the prediction of a thermal striping in a triple jet is performed. The tested turbulence models are the two-layer model, the shear stress transport model, and the elliptic relaxation model. These three turbulence models are applied to the prediction of a thermal striping in a triple jet in which detailed experimental data are available. The predicted time-averaged and root-mean-square values of the temperature are compared with the experimental data, and the capability of predicting the oscillatory behavior of the ensemble-averaged temperature is investigated. From these works, it is shown that only the elliptic relaxation model is capable of predicting the oscillatory behavior of the ensemble-averaged temperature. It is also shown that the elliptic relaxation model predicts best the time-averaged temperature and the root mean square of the temperature fluctuation. However, this model predicts a slower mixing at the far downstream of the jet.
A Comparative Numerical Study of Particle Mixing on Different Grate Designs Through the Discrete Element Method
Authors: Kruggel-Emden Harald , Simsek Erdem , Wirtz Siegmar , Scherer Viktor
Published: October 2007

Based on LEAT’s discrete element codes, granular flow and mixing on conveying equipment are studied in two and three dimensions. Discrete element simulations, which are briefly introduced, provide detailed information on particle positions and velocities over time. This information is used to derive quantities characterizing the dynamic process of mixing. The main focus of the study presented is the mixing process of inhomogeneous particle ensembles on different grate types. For this purpose, the introduced mixing parameters are used to compare the mixing in a 3D situation with the corresponding 2D approximation on identical grates and to compare different grate designs in two dimensions.
Lateral Loading of Internally Pressurized Steel Pipes
Authors: Gresnigt Arnold M. , Karamanos Spyros A. , Andreadakis Kyros P.
Published: October 2007

This paper examines the denting response of pipes subjected to lateral (transverse) quasistatic wedge loading, in the presence of internal pressure. Pipes are modeled with nonlinear shell finite elements and a simplified analytical model. The analysis focuses on the significant influence of internal pressure on the denting resistance. Furthermore, the effects of wedge denting device orientation on the denting resistance are briefly discussed. Motivated by the experimental and numerical results, a two-dimensional heuristic model is proposed, which yields closed-form expressions for the denting force in terms of the corresponding displacement. The finite element results and the model equations are in good agreement with the experimental results and illustrate pipe denting response in an elegant manner.
Prediction of Fracture Stresses of High Pressure Gas Cylinders
Containing Cracklike Flaws
Authors: Rana Mahendra D. , Rawls George B.
Published: October 2007

Full scale tests were conducted on high pressure gas cylinders containing cracklike flaws. The cylinders were then pressurized to destruction, and the membrane hoop stress at failure in the cylinder wall was calculated from the failure pressure. Mechanical properties, including tensile and fracture data, were obtained on specimens representing the heats of the tested cylinders. Analyses were performed to predict the failure stresses using several methods available in the open literature. This paper presents the results of the predicted and measured fracture stresses.
Novel Formulation of the Tightening and Breakaway Torque Components in Threaded Fasteners
Authors: Nassar Sayed A. , Yang Xianjie
Published: October 2007

New formulas are developed for the torque-tension relationship, various torque components, and breakaway torque values in threaded fastener applications. The three-dimensional aspects of the lead helix and thread profile angles and the kinetic and static friction coefficients are all taken into account. Two scenarios of the contact pressure between threads and under the turning fastener head are considered, namely, uniformly distributed and linearly distributed contact pressure scenarios. The effect of thread pitch, lead helix and thread profile angles, friction coefficients, and fastener geometry is discussed. Results from the new formulas are compared with the approximate torque-tension relationship provided in the literature. A percentage difference analysis indicates that the new formulas provide a significant improvement that would enhance the reliability and safety of bolted connections, especially in critical applications.
Stress Classification Using the r-Node Method
Authors: Fanous Ihab F. Z. , Seshadri R.
Published: October 2007

The ASME Code Secs. III and VIII (Division 2) provide stress-classification guidelines to interpret the results of a linear elastic finite element analysis. These guidelines enable the splitting of the generated stresses into primary, secondary, and peak. The code gives some examples to explain the suggested procedures. Although these examples may reflect a wide range of applications in the field of pressure vessel and piping, the guidelines are difficult to use with complex geometries. In this paper, the r-node method is used to investigate the primary stresses and their locations in both simple and complex geometries. The method is verified using the plane beam and axisymmetric torispherical head. Also, the method is applied to analyze 3D straight and oblique nozzles modeled using both solid and shell elements. The results of the analysis of the oblique nozzle are compared with recently published experimental data.
Optimum Replacement Interval for Mechanical Components Based on Fatigue Reliability
Authors: Park Young H. , Tang Jun
Published: October 2007

This paper introduces a maintenance decision-making strategy in the general area of replacement and reliability of mechanical components. The decision-making strategy involves the optimization of replacement interval calculated from fatigue failure of mechanical components. The proposed approach is based on the cumulative damage distribution function for evaluating mean fatigue life. Using this approach, the analytical expressions for mean and variance of the cumulative damage distribution under both stationary narrow-band and stationary wide-band random process are provided. The mean value and variance of fatigue life distribution are then evaluated to determine the optimal replacement intervals under fatigue failure. A practical example is presented to demonstrate the application of the present method.