bluuebunny/crossref_metadata_2025 huggingface dataset:
Change of the growth hormone–insulin-like growth factor-I axis in patients with gastrointestinal cancer: related to tumour type and nutritional status
Authors: Huang Qi , Nai Yong-Jun , Jiang Zhi-Wei , Li Jie-Shou
Published: July 2005

Changes in the growth hormone (GH)–insulin-like growth factor-I (IGF-I) axis, especially acquired GH resistance, develop in many severe illnesses, including cachexia. To study changes in the GH–IGF-I axis in patients with cancer cachexia, biochemical markers and body composition parameters were measured in eighty-eight gastric cancer patients, thirty colorectal cancer patients (subclassified according to the presence or absence of cachexia) and twenty-four healthy control subjects. Fifty-nine patients were defined as cachectic, based on the percentage of weight loss compared with their previous normal weight. The remaining fifty-nine patients were defined as non-cachectic. Measurements were repeated in twenty-seven patients (sixteen with gastric cancer and eleven with colorectal cancer) 3 months after radical operation. Compared with the controls, the cachectic gastric cancer patients had high GH levels (1·36v. 0·32 ng/ml;P=0·001), a trend towards high IGF-I levels (223·74v. 195·15 ng/ml;P=0·128 compared with non-cachectic patients) and a low log IGF-I/GH ratio (2·55 and 2·66v. 3·00;P=0·002), along with a decreased BMI; the cachectic colorectal cancer patients showed the biochemical characteristics of acquired GH resistance: high GH (0·71v. 0·32 ng/ml;P=0·016), a trend towards decreased IGF-I levels (164·18v. 183·24 ng/ml;P=0·127) and a low log IGF-I/GH ratio (2·54v. 2·99;P=0·005), with increased IGF-I levels following radical surgery (200·49v. 141·91 ng/ml;P=0·046). These findings suggest that normal GH reaction and sensitivity occur in gastric cancer patients, controlled by nutritional status, whereas acquired GH resistance develops in cachectic colorectal cancer patients, which may be caused by tumour itself.
Bioavailability of vitamin D2 from irradiated mushrooms: an in vivo study
Authors: Jasinghe Viraj J. , Perera Conrad O. , Barlow Philip J.
Published: July 2005

Vitamin D2 from irradiated edible mushrooms might present a possible dietary source of this vitamin, subject to its bioavailability. Having previously optimized a method for the conversion of ergosterol in mushrooms to vitamin D2, this paper examines the vitamin D-enriched mushrooms (Lentinula edodes) for their bioavailability of the vitamin, using an animal model. Thirty male Wistar rats were fed for 1 week with a diet deficient in vitamin D. After this 1-week period, six rats were randomly selected and killed for analysis of initial bone mineral density, and serum level of 25-hydroxyvitamin D. A group of twelve rats of the test animals received 1 μg of vitamin D2 from irradiated mushrooms for a period of 4 weeks until being killed. The remaining twelve rats were fed un-irradiated mushrooms at the same level to act as controls. At the end of a 4-week period, the mean serum 25-hydroxyvitamin D level of the experimental group was 129·42 (sd 22·00) nmol/l whereas it was only 6·06 (sd 1·09) nmol/l in the control group. Femur bone mineral density of the experimental group of animals was significantly higher (P<0·01) than the control group. In addition, serum Ca concentrations among groups were shown to be significantly higher (P<0·01). It may be concluded from the results that vitamin D2 from UV-irradiated mushrooms is well absorbed and metabolized in this model animal system. Significant increase in femur bone mineralization (P<0·01) was shown in the presence of vitamin D2 from irradiated mushrooms compared with the controls.
Consistent dietary patterns identified from childhood to adulthood: The Cardiovascular Risk in Young Finns Study
Authors: Mikkilä V. , Räsänen L. , Raitakari O.T. , Pietinen P. , Viikari J.
Published: July 2005

Dietary patterns are useful in nutritional epidemiology, providing a comprehensive alternative to the traditional approach based on single nutrients. The Cardiovascular Risk in Young Finns Study is a prospective cohort study with a 21-year follow-up. At baseline, detailed quantitative information on subjects' food consumption was obtained using a 48 h dietary recall method (n1768, aged 3–18 years). The interviews were repeated after 6 and 21 years (n1200 andn1037, respectively). We conducted a principal component analysis to identify major dietary patterns at each study point. A set of two similar patterns was recognised throughout the study. Pattern 1 was positively correlated with consumption of traditional Finnish foods, such as rye, potatoes, milk, butter, sausages and coffee, and negatively correlated with fruit, berries and dairy products other than milk. Pattern 1 type of diet was more common among male subjects, smokers and those living in rural areas. Pattern 2, predominant among female subjects, non-smokers and in urban areas, was characterised by more health-conscious food choices such as vegetables, legumes and nuts, tea, rye, cheese and other dairy products, and also by consumption of alcoholic beverages. Tracking of the pattern scores was observed, particularly among subjects who were adolescents at baseline. Of those originally belonging to the uppermost quintile of pattern 1 and 2 scores, 41 and 38 % respectively, persisted in the same quintile 21 years later. Our results suggest that food behaviour and concrete food choices are established already in childhood or adolescence and may significantly track into adulthood.
Body composition predicted from skinfolds in African women: a cross-validation study using air-displacement plethysmography and a black-specific equation
Authors: Dioum Aïssatou , Gartner Agnès , Maire Bernard , Delpeuch Francis , Wade Salimata
Published: July 2005

Skinfold thickness (SF) measurements are commonly used for the indirect assessment of body composition. It is necessary to know how large the bias is when using Caucasian SF-based prediction equations Africans, as no specific equations exist. Our first aim was to test the validity of the equation of Durnin & Womersley for predicting body density from SF in Africans. The second aim was to determine the effect of calculating percentage body fat (%BF) from body density using a black-specific formula rather than the Siri equation, thus taking into account the higher fat-free mass (FFM) density in blacks than in whites. A total of 196 African women volunteered. Mean age was 29·5 (sd 8·7) years and mean BMI was 22·5 (sd 4·6) kg/m2. We compared body density values predicted from SF with those measured by air-displacement plethysmography, and %BF values obtained from body density using the Siri equation or the black-specific calculation. The bias (reference minus prediction) was 0·0100 kg/cm3 in body density (P<10−4) and 6·5 % BF (P<10−4), and the error (sd of the bias) 0·0097 kg/l and 4·5 % BF. With the black-specific equation, the bias was reduced by 1·9 % BF, while error remained similar. As the %BF prediction required an SF-based equation followed by a body density-based calculation, the lack of validity we observed in Africans may be due to known differences between blacks and whites in the distribution of subcutaneous adipose tissue and, as demonstrated, in the FFM density. Equations thus need to be established using SF values specific to Africans.
Consumption of red meat, white meat and processed meat in Irish adults in relation to dietary quality
Authors: Cosgrove Meadhbh , Flynn Albert , Kiely Máiréad
Published: July 2005

The aim of the present study was to examine the association of red meat, white meat and processed meat consumption in Irish adults with dietary quality. A cross-sectional study of subjects, randomly selected using the electoral register, estimated habitual food intakes using a 7 d food diary in a nationally representative sample of 662 men and 717 women (not pregnant or lactating) aged 18–64 years. Consumers were classified into thirds, based on the distribution of mean daily intakes for red meat, white meat and processed meat. The mean intakes of red meat, white meat and processed meat were 51, 33 and 26 g/d respectively, and men consumed significantly more (P<0·001) than women for all meat types. In men, red meat consumption was associated with lower (P<0·001) prevalence of inadequacy for Zn, riboflavin and vitamin C intakes. Increasing processed meat intake was associated with a lower (P<0·01) level of compliance with dietary recommendations for fat, carbohydrate and fibre in men. Increasing processed meat consumption was associated with lower (P<0·01) wholemeal bread, vegetables, fruit and fish intakes in men and women. Managerial occupations were associated with lower processed meat intakes. It is important to distinguish between meat groups, as there was a large variation between the dietary quality in consumers of red meat, white meat and processed meat. Processed meat consumption is negatively associated with dietary quality and might therefore be a dietary indicator of poor dietary quality. This has important implications in nutritional epidemiological studies and for the development of food-based dietary guidelines.
Optimizing oral nutritional drink supplementation in patients with chronic obstructive pulmonary disease
Authors: Broekhuizen Roelinka , Creutzberg Eva C. , Weling-Scheepers Clarie A. P. M. , Wouters Emiel F. M. , Schols Annemie M. W. J.
Published: July 2005

Nutritional support is indicated in some patients with chronic obstructive pulmonary disease to restore nutritional status and improve functional capacity. However, the efficacy of nutritional supplements is sometimes disappointing, partly owing to a compensatory drop in habitual food intake. We retrospectively studied the effect of nutritional drink supplements, differing in portion size and energy content, on weight gain and body composition. Thirty-nine patients with stable chronic obstructive pulmonary disease, participating in an 8-week pulmonary rehabilitation programme and eligible for nutritional support, were studied. Group A (n19) received three portions of 125 ml (2380 kJ), whereas group B (n20) received three portions of 200 ml (3350 kJ) daily. The macronutrient composition of the regimens was similar (20 % protein, 60 % carbohydrates and 20 % fat). Lung function, body weight, body composition (by bio-electrical impedance analysis), habitual dietary intake (by dietary history) and resting energy expenditure (by ventilated hood) were determined. Weight gain was compared with expected weight as predicted by a computer simulation model. Although patients in both groups significantly increased in weight, this increase was higher in group A (A, 3·3 (sd 1·9) kg; B, 2·0 (sd 1·2) kg;P=0·019), while receiving less energy. The observed weight gain in group A was similar to that expected, but in group B it was lower than expected (P<0·001). In both groups, fat-free mass and fat mass were gained in a ratio of 2:1, fat-free mass increasing primarily during the first 4 weeks. This study illustrates that there might be an optimum for the portion size of nutritional drink supplements in chronic obstructive pulmonary disease and that more is not always better.
Effects of energy restriction and fish oil supplementation on renal guanidino levels and antioxidant defences in aged lupus-prone B/W mice
Authors: Jung Kim You , Yokozawa Takako , Chung Hae Young
Published: July 2005

Energy restriction (ER) and dietary fish oil (FO) are known to reduce the severity of glomerulonephritis and increase the lifespan of lupus-prone (NZB×NZW) F1(B/W) mice. In the present study, mice were fed eitherad libitumor energy-restricted (a 40 % lower energy intake than the dietad libitum), semi-purified diets containing 5 % maize oil or 5 % fish oil supplementation. To estimate the renal damage associated with oxidative stress, the total amounts of reactive oxygen species (ROS), cyclooxygenase-derived ROS and levels of guanidino compounds were measured. Additionally, we assessed the putative action of ER and FO on several key antioxidant enzymes measured in the kidney post-mitochondrial fraction. Results showed that the age-related increase in creatinine level was significantly reduced by ER and FO in old mice. In contrast, arginine and guanidino acetic acid levels showed a decrease with age but were increased by ER and FO. The GSH:GSSG ratio showed a significant decrease with age, whereas ER and FO feeding prevented the decrease. The age-related decrease in antioxidant scavenging superoxide dismutase, catalase and glutathione peroxidase activities were all reversed by ER and FO. The moderately decreased glutathione reductase and glutathione-S-transferase activities with age were significantly increased by ER and FO. Furthermore, the increased total ROS and cyclooxygenase-derived ROS levels were effectively reduced by ER and FO. In conclusion, our data strongly indicate that ER and FO maintain antioxidant status and GSH:GSSG ratio, thereby protecting against renal deterioration from oxidative insults during ageing.
Horizons in Nutritional Science
Authors: Otto Bärbel , Spranger Jochen , Benoit Stephen C. , Clegg Debbie J. , Tschöp Matthias H.
Published: July 2005

The appetite-modulating peptide ghrelin is predominantly produced and secreted by the stomach and shows a strong growth hormone-releasing activity, which is mediated by the activation of the so-called growth hormone secretagogue type 1a receptor. Ghrelin is involved in the regulation of energy balance by increasing food intake and reducing fat utilization. Additionally, it stimulates lactotroph and corticotroph function, influences the pituitary gonadal axis, inhibits pro-inflammatory cytokine expression, controls gastric motility and acid secretion and influences pancreatic exocrine and endocrine function, as well as impacting on glucose metabolism. This review summarizes the known functions of ghrelin and its role in the regulation of the gut–brain axis.
Treatment of obesity: Theory into practice
Authors: Kirk Sara F. L.
Published: July 2005

The purpose of the present paper is to outline the current situation in the management of obesity in adults, and to make some suggestions as to how health professionals involved in obesity treatment can best address this growing problem. Dietitians and nutritionists have long been involved in the treatment of obesity, and have a vital role to play in the battle to reverse the increasing prevalence of this major public health problem. However, the current management of obesity is far from ideal. There is evidence to suggest that in general health care, even when there are clearly effective clinical interventions, health professionals may not practise in the best way. Furthermore, some professionals may also hold negative attitudes towards the obese. These are the subject of a systematic review on improving health professionals' practice and organization of care in obesity treatment, the preliminary findings of which will be discussed in the present paper (Harveyet al.1998a,b). A new approach to obesity is required, encompassing effective treatment and prevention strategies. A greater understanding of the problems faced by the obese individual in attempting to lose weight is also needed, with a range of treatment approaches on offer to acknowledge the heterogeneity of obesity. Those health professionals involved in obesity treatment must consider the impact of dietary advice given in a consultation against the impact of environmental cues that assail the patient as soon as they leave the room. Tackling the obesity epidemic requires action at the individual and population level if we are to see any reduction in prevalence.
Influence of intense physical activity on energy balance and body fatness
Authors: Tremblay Angelo
Published: July 2005

The reduced contribution of physical activity to daily energy expenditure and the accessibility to high-fat foods have put an excessive burden on energy balance, resulting in an increase in the prevalence of obesity throughout the world. In this context, fat gain can be seen as a natural adaptation to deal with a fattening lifestyle, since the hormonal adaptations that accompany fat gain favour the readjustment of energy expenditure to energy intake. Intense physical activity would also seem to facilitate the regulation of energy balance, since it increases the energy cost of exercise, increases post-exercise energy expenditure and the potential of skeletal muscles to utilize lipids, and also favours a decrease in post-exercise intake. Moreover, the effects of intense exercise seem to be mediated by an activation of sympathetic nervous system activity that seems to be specific to skeletal muscle. It is also important to manipulate macronutrient composition in order to reduce fat intake, because unhealthy food habits can favour overfeeding and thus overcome the energy deficit caused by regular physical activity. Under free-living conditions, the combination of vigorous activity and healthy food practices can amount to a substantial weight loss which is comparable with that of other non-surgical approaches to treat obesity.
What processes are involved in the appetite response to moderate increases in exercise-induced energy expenditure?
Authors: King Neil A.
Published: July 2005

It is intuitive that an energy deficit induced by exercise induces an automatic increased drive for food (hunger and energy intake). However, the absence of a compensatory increase in energy intake (EI) in response to an exercise-induced increase in energy expenditure (EE) is now well documented. Thus, there is a weak coupling between exercise-induced increases in EE and EI. One paradox related to the phenomenon of a weak coupling between the exercise-induced EE and EI is the observation of a positive relationship between physical activity and food intake in the long-term free-living situation (i.e. tight coupling between EE and EI). It is possible, therefore, that a period of transition (uncoupling) occurs in the short-term, before a steady-state (coupling) condition is achieved. It is likely that a combination of physiological and behavioural adaptations occur in order to achieve a tight coupling between EE and EI. The precise physiological and behavioural changes that take place to obtain a new equilibrium (i.e. coupling between EE and EI) are still undetermined. The expectation that exercise-induced increases in EE should drive up hunger and food intake tends to be based on the concept of a strong coupling between physiology and behaviour. However, because of the individual's strong volitional control over eating behaviour, the psychological influences on the appetite response to exercise should not be undervalued. The psychological position of the individual (e.g. dietary restraint, food-related cognitions, reasons for exercising) could have a very strong influence on the food intake response to exercise. Misjudgements concerning the energy value of the food (EI) relative to the energy value of the exercise (EE) could be one possibility why exercise fails to be a successful method of weight loss for some individuals.
The effect of inactivity on dietary intake and energy homeostasis
Authors: Ritz P. , Elia M.
Published: July 2005

Reduced physical activity commonly occurs in patients with disease or chronic disabilities, in the elderly, and in certain patients with obesity. Surprisingly, information on the effect of inactivity on energy homeostasis is scarce and often difficult to interpret. In models of reduced physical activity, such as space flights, bed-rest and confinement, subjects frequently lose weight (<5 %), predominantly in the form of fat-free mass. In some cases this is compensated by an increase in fat mass, which means that changes in weight are poor indicators of energy balance. The extent to which spontaneous reduction in energy intake (in most studies energy intake is fixed) compensates or overcompensates for the reduction in energy expenditure (mainly physical activity and to a small extent in BMR, typically <6 %) is largely underexamined. Preliminary observations suggesting that there is a preferential selection of low-energy-dense foods (low in fat) require confirmation under carefully controlled experimental conditions. It is concluded that a comprehensive and systematic evaluation is needed to address the effects and relevance of various degrees of physical inactivity to energy homeostasis, in relation to disease and space medicine.
Modelling in nutrition: An introduction
Authors: Wilson Peter D. G. , Dainty Jack R.
Published: July 2005

The purpose of the present paper is to provide an introduction to modelling, particularly mathematical modelling, for nutritional researchers with little or no experience of the modelling process. It aims to outline the function of modelling, and to give some guidance on factors to consider when designing protocols to generate data as part of the modelling process. It is not intended in any way to be a comprehensive guide to mathematical modelling. The paper discusses the uses of modelling, and presents a ‘hydrodynamic analogy’ to compartmental modelling, to explain the process to the non-mathematically-minded and to examine some of the pitfalls to be avoided when using stable-isotope tracers. Examples of the use of modelling in nutrition are presented, including methods for determining absorption, as well as a discussion of possible future avenues for nutritional modelling.
The bioavailability of non-nutrient plant factors: dietary flavonoids and phyto-oestrogens
Authors: Wiseman Helen
Published: July 2005

The bioavailability in human subjects of non-nutrient plant factors, including dietary flavonoids and phyto-oestrogens, is of great importance relative to their reported health protective effects. These effects include protection against heart disease, and also in the case of the phyto-oestrogens, hormone-dependent cancers. Epidemiological studies have shown flavonoid intake (mostly quercetin) to be inversely associated with mortality from CHD. Quercetin is a potent antioxidantin vitro, and protection against the oxidative damage to LDL implicated in atherogenesis has been suggested as a possible mechanism. Human subjects can absorb significant amounts of quercetin (particularly in the glucoside form) and it would appear to be sufficiently bioavailable to act as an antioxidantin vivo;however, following our recent study (J O'Reilly, TAB Sanders and H Wiseman, unpublished results), it is currently less clear whether quercetin really can act as an antioxidantin vivo. The isoflavone phyto-oestrogens genistein and daidzein are much less effective antioxidants than quercetinin vitro, however, they are well-absorbed by human subjects and appear to be sufficiently bioavailable to act as antioxidantsin vivo. In our recent study (O'Reillyet al.1998) lower plasma isoprostane concentrations and increased resistance of LDL to oxidation were observed following the high-isoflavone dietary phase compared with the low-isoflavone dietary phase. Considerable inter-individual variation in isoflavone metabolite excretion has been observed, in particular the production of equol (the gut bacterial metabolite of daidzein; a more potent antioxidant and more oestrogenic than daidzein), and this appears to be influenced by habitual diet. Further studies on the bioavailability of these non-nutrient plant factors and related influencing factors are clearly still required.
Lipoprotein atherogenicity: an overview of current mechanisms
Authors: Griffin Bruce A.
Published: July 2005

Raised serum cholesterol does not adequately explain the increased risk of CHD within populations or the relationship between diet and CHD. Nevertheless, the principal transport vehicle of cholesterol in the circulation, LDL, must still be regarded as the most atherogenic lipoprotein species, but not because of its contribution to serum cholesterol. The atherogenic potential of LDL in the majority of individuals arises from an increase in the number of small dense LDL particles and not from its cholesterol contentper se. There is now a wealth of evidence from cross-sectional and prospective studies to show that LDL particle size is significantly associated with CHD and predictive of increased coronary risk. Moreover, there are a number of credible mechanisms to link small dense LDL with the atherogenic process. The rate of influx of serum lipoproteins into the arterial wall is a function of particle size, and will thus be more rapid for small dense LDL. Components of the extracellular tissue matrix in the intima, most notably proteoglycans, selectively bind small dense LDL with high affinity, sequestering this lipoprotein in a pro-oxidative environment. The oxidation of LDL promotes the final deposition of cholesterol in the arterial wall, and numerous studies have shown small dense LDL to be more susceptible to oxidative modification than its larger and lighter counterparts. An increase in the number of small dense LDL particles may originate from a defect in the metabolism of triacylglycerol-rich lipoproteins. One mechanism may involve the overproduction and increased residence time of large triacylglycerol-rich VLDL in the postprandial phase, a situation thought to arise through pathways of insulin resistance.
Strategies for altering population intakes of fats and fatty acids
Authors: Gibney M. J.
Published: July 2005

Quantitative dietary guidelines for fats were first issued in 1977 in the USA and these guidelines have changed little since then. In the UK only 14 % of the population achieve the dietary goal for fat (33 % energy) and only 3 % achieve the target (10 % energy) from saturated fatty acids. Analysis of the Dietary and Nutritional Survey of British Adults reveals that across quartiles of decreasing total fat intake, the actual fatty acid composition of this fat does not alter; i.e. when total fat is lowered, all fatty acid categories are equally lowered. This arises because 85 % of total fat and of each of the categories of fatty acids are provided by just five foods (milk, meat, cereals, spreads and vegetables). When total fat in the UK is lowered, the intake of polyunsaturated fatty acids is lowered. The problem is that if the intake of polyunsaturated fatty acids falls below a threshold of about 5 % energy, the cholesterol-raising properties of certain saturated fatty acids, e.g. myristic acid, are greatly augmented. In order to alter the balance of dietary fatty acids, more data are needed on food choices of those in the population achieving particular targets. These targets cannot be based on existing dietary goals, since so few people attain them. A new set of‘interim attainable dietary guidelines’, based on prevailing dietary intakes, must be the basis for establishing sensible food-based dietary guidelines.
Dietary carbohydrates and triacylglycerol metabolism
Authors: Roche Helen M.
Published: July 2005

There is a growing body of scientific evidence which demonstrates that plasma triacylglycerol (TAG) concentration, especially in the postprandial state, is an important risk factor in relation to the development of CHD. Postprandial hypertriacylglycerolaemia is associated with a number of adverse metabolic risk factors, including the preponderance of small dense LDL, low HDL-cholesterol concentrations and elevated factor VII activity. Traditionally, a low-fat high-carbohydrate diet was used to prevent CHD because it effectively reduces plasma cholesterol concentrations, but this dietary regimen increases plasma TAG concentrations and reduces HDL-cholesterol concentrations. There is substantial epidemiological evidence which demonstrates that high plasma TAG and low plasma HDL concentrations are associated with an increased risk of CHD. Thus, there is reason for concern that the adverse effects of low-fat high-carbohydrate diets on TAG and HDL may counteract or negate the beneficial effect of reducing LDL-cholesterol concentrations. Although there have been no prospective studies to investigate whether reduced fat intake has an adverse effect on CHD, there is strong epidemiological evidence that reducing total fat intake is not protective against CHD. On the other hand, high-fat diets predispose to obesity, and central obesity adversely affects TAG metabolism. There is substantial evidence that in free-living situations low-fat high-carbohydrate diets lead to weight loss, which in turn will correct insulin resistance and plasma TAG metabolism. Clearly there is a need for prospective studies to resolve the issue as to whether low-fat high-carbohydrate diets play an adverse or beneficial role in relation to the development of CHD.
The Espinet and the perceptual learning effects in flavour aversion conditioning: Do they depend on a common inhibitory mechanism?
Authors: Artigas Antonio A. , Sansa Joan , Prados José
Published: July 2005

In three experiments rats were given short or long preexposure (4 or 10 sessions) to two compound flavours, AX and BX, according to an intermixed or a blocked schedule. Following preexposure, aversion conditioning trials were given with AX as the conditioned stimulus (CS). In Experiments 1 and 2, retardation and summation tests were then carried out to assess the inhibitory properties of B (an Espinet procedure). In Experiment 3, test trials evaluated generalization from AX to BX (the standard perceptual learning procedure). The results showed that B performed as an inhibitor of the unconditioned stimulus (US; an Espinet effect) only after long intermixed preexposure, whereas a reliable perceptual learning effect was observed both after short and after long preeexposure. The observation that B had no detectable inhibitory properties after short preexposure casts doubt on the suggestion that inhibitory learning is responsible for perceptual learning after brief exposure to AX and BX.
Induction when rats lick for 1% liquid-sucrose reinforcement
Authors: Weatherly Jeffrey N. , Lang Kelsey K. , King Brent M. , Beste Ryan , Grove Cathryn
Published: July 2005

Previous research reported that rats responding for 1% liquid-sucrose reinforcement when 32% sucrose reinforcement is upcoming will decrease their response rate (contrast) if licking is the dependent measure and increase their response rate (induction) if pressing a lever is the dependent measure. The present study investigated whether induction could be observed when licking served as the dependent measure and whether induction in lever pressing and contrast in licking behaviour could be concurrently observed. Experiment 1 found induction when rats licked to earn the rewards but consumed them at a location separate from the spout licked to earn them. Experiment 2 also found induction when rats earned (and consumed) rewards by licking the same spout throughout the session. Experiment 3 separately measured instrumental lever pressing for sucrose rewards and licking the sucrose during the reward period. We found that both measures increased for 1% sucrose when 32% sucrose reinforcement was upcoming. The present results indicate that the type of response is not the sole determinant of whether contrast or induction is observed. Rather, they suggest that other procedural details, such as the location of reinforcer delivery, influence which effect is observed. The results also indicate that associative processes underlie the appearance of induction in responding for 1% sucrose.
𝑝-Rider sets are 𝑞-Sidon sets
Authors: Lefèvre P. , Rodríguez-Piazza L.
Published: July 2005

The aim of this paper is to prove that for every

p
>

4
3

p>{\frac 43}

, every

p
p

-Rider set is a

q
q

-Sidon set for all

q
>

p

2
−
p

⋅

q>{\frac p{2-p}}\cdot

This gives some positive answers for the union problem of

p
p

-Sidon sets. We also obtain some results on the behavior of the Fourier coefficient of a measure with spectrum in a

p
p

-Rider set.
A global compactness result for singular elliptic problems involving critical Sobolev exponent
Authors: Cao Daomin , Peng Shuangjie
Published: July 2005

Let

Ω
⊂

R
N

\Omega \subset R^N

be a bounded domain such that
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="0 element-of normal upper Omega comma upper N greater-than-or-equal-to 3 comma 2 Superscript asterisk Baseline equals StartFraction 2 upper N Over upper N minus 2 EndFraction comma lamda element-of upper R comma epsilon element-of upper R">

0
∈
Ω
,
N
≥
3
,

2
∗

=

2
N

N
−
2

,
λ
∈
R
,
ϵ
∈
R

0 \in \Omega , N \geq 3,2^*=\frac {2N}{N-2},\lambda \in R, \epsilon \in R

. Let

{

u
n

}
⊂

H
0
1

(
Ω
)

\{u_n\}\subset H_0^1(\Omega )

be a (P.S.) sequence of the functional
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper E Subscript lamda comma epsilon Baseline left-parenthesis u right-parenthesis equals one half integral Underscript normal upper Omega Endscripts left-parenthesis StartAbsoluteValue nabla u EndAbsoluteValue squared minus StartFraction lamda u squared Over StartAbsoluteValue x EndAbsoluteValue squared EndFraction minus epsilon u squared right-parenthesis minus StartFraction 1 Over 2 Superscript asterisk Baseline EndFraction integral Underscript normal upper Omega Endscripts StartAbsoluteValue u EndAbsoluteValue Superscript 2 Super Superscript asterisk Baseline">

E

λ
,
ϵ

(
u
)
=

1
2

∫

Ω

(

|

∇
u

|

2

−

λ

u
2

|

x

|

2

−
ϵ

u
2

)
−

1

2
∗

∫

Ω

|

u

|

2
∗

E_{\lambda ,\epsilon }(u)=\frac {1}{2}\int _{\Omega }(|\nabla u|^{2}-\frac {\lambda u^2}{|x|^2}-\epsilon u^2)-\frac {1}{2^*}\int _{\Omega } |u|^{2^*}

. We study the limit behaviour of

u
n

u_n

and obtain a global compactness result.
Some remarks on Liouville type results for quasilinear elliptic equations
Authors: Dancer E. , Du Yihong
Published: July 2005

For a wide class of nonlinearities

f
(
u
)

f(u)

satisfying
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="f left-parenthesis 0 right-parenthesis equals f left-parenthesis a right-parenthesis equals 0 comma f left-parenthesis u right-parenthesis greater-than 0 in left-parenthesis 0 comma a right-parenthesis and f left-parenthesis u right-parenthesis greater-than 0 in left-parenthesis a comma normal infinity right-parenthesis comma">

 

f
(
0
)
=
f
(
a
)
=
0

, 

f
(
u
)
>
0

 in 

(
0
,
a
)

 and 

f
(
u
)
>
0

 in 

(
a
,
∞
)

,

\mbox { $f(0)=f(a)=0$, $f(u)>0$ in $(0,a)$ and $f(u)>0$ in $(a,\infty )$,}

\]
we show that any nonnegative solution of the quasilinear equation

−

Δ
p

u
=
f
(
u
)

-\Delta _p u= f(u)

over the entire

R

N

\mathbb {R}^N

must be a constant. Our results improve or complement some recently obtained Liouville type theorems. In particular, we completely answer a question left open by Du and Guo.
Rescalings of free products of II₁–factors
Authors: Dykema Ken , Rădulescu Florin
Published: July 2005

We introduce the notation

Q

(
1
)
∗
⋯
∗

Q

(
n
)
∗
L
(

F

r

)

\mathcal {Q}(1)*\cdots *\mathcal {Q}(n)*L(\mathbf F_r)

for von Neumann algebra II

1

_1

–factors where

r
r

is allowed to be negative. This notation is defined by rescalings of free products of II

1

_1

–factors, and is proved to be consistent with known results and natural operations. We also give two statements which we prove are equivalent to isomorphism of free group factors.
Nonvanishing of Fourier coefficients of modular forms
Authors: Alkan Emre
Published: July 2005

Let

f
=

∑

n
=
1

∞

a
f

(
n
)

q
n

f=\sum _{n=1}^\infty a_f(n)q^n

be a cusp form with integer weight

k
≥
2

k\ge 2

that is not a linear combination of forms with complex multiplication. For

n
≥
1

n\ge 1

, let
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="i Subscript f Baseline left-parenthesis n right-parenthesis colon equals max left-brace right-brace colon i colon equals equals times times af left-parenthesis right-parenthesis plus plus nj times times 0 separator for all less-than-or-equal-to less-than-or-equal-to less-than-or-equal-to 0 ji period">

i
f

(
n
)
:=
max
{
i
:

a
f

(
n
+
j
)
=
0

for all 

0
≤
j
≤
i

}
.

i_f(n):=\max \{i:a_f(n+j)=0\quad \text {for all $0\le j\le i$}\}.

\]
Improving on work of Balog, Ono, and Serre we show that

i
f

(
n
)

≪

f
,
ϕ

ϕ
(
n
)

i_f(n)\ll _{f,\phi }\phi (n)

for almost all

n
n

, where

ϕ
(
x
)

\phi (x)

is any good function (e.g. such as

log
⁡
log
⁡
(
x
)

\log \log (x)

) monotonically tending to infinity with

x
x

. Using a result of Fouvry and Iwaniec, if

f
f

is a weight 2 cusp form for an elliptic curve without complex multiplication, then we show for all

n
n

that

i
f

(
n
)

≪

f
,
ε

n

69
169

+
ε

i_f(n)\ll _{f,\varepsilon } n^{\frac {69}{169}+\varepsilon }

. We also obtain conditional results depending on the Generalized Riemann Hypothesis and the Lang-Trotter Conjecture.
Similarity to an isometry of a composition operator
Authors: Bayart Frédéric
Published: July 2005

We study the composition operators which are similar to an isometry on the classical Hardy space

H
2

(

D

)

H^2(\mathbb {D})

.
Bicyclic units of ℤ𝕊_{𝕟}
Authors: Olivieri Aurora , del Río Ángel
Published: July 2005

We prove that the group generated by the bicyclic units of

Z

S
n

\mathbb {Z} S_n

has torsion for

n
≥
4

n\ge 4

. This answers a question of Sehgal (1993).
Stability and convergence of discrete kinetic approximations to an initial-boundary value problem for conservation laws
Authors: Milišić Vuk
Published: July 2005

We present some new convergence results for a discrete velocities BGK approximation to an initial boundary value problem for a single hyperbolic conservation law. In this paper we show stability and convergence toward a unique entropy solution in the general

B
V

BV

framework without any restriction either on the data of the limit problem or on the set of velocity of the BGK model.
Functional equations and their related operads
Authors: Minasian Vahagn
Published: July 2005

Using functional equations, we define functors that generalize standard examples from calculus of one variable. Examples of such functors are discussed, and their Taylor towers are computed. We also show that these functors factor through objects enriched over the homology of little

n
n

-cubes operads and discuss the relationship between functors defined via functional equations and operads. In addition, we compute the differentials of the forgetful functor from the category of

n
n

-Poisson algebras in terms of the homology of configuration spaces.
Aleksandrov surfaces and hyperbolicity
Authors: Oh Byung-Geun
Published: July 2005

Aleksandrov surfaces are a generalization of two-dimensional Riemannian manifolds, and it is known that every open simply-connected Aleksandrov surface is conformally equivalent either to the unit disc (hyperbolic case) or to the plane (parabolic case). We prove a criterion for hyperbolicity of Aleksandrov surfaces which have nice tilings and where negative curvature dominates. We then apply this to generalize a result of Nevanlinna and give a partial answer for his conjecture about line complexes.
On the mod 𝑝 cohomology of 𝐵𝑃𝑈(𝑝)
Authors: Vavpetič Aleš , Viruel Antonio
Published: July 2005

We study the mod 

p
p

cohomology of the classifying space of the projective unitary group

P
U
(
p
)

PU(p)

. We first prove that conjectures due to J.F. Adams and Kono and Yagita (1993) about the structure of the mod 

p
p

cohomology of the classifying space of connected compact Lie groups hold in the case of

P
U
(
p
)

PU(p)

. Finally, we prove that the classifying space of the projective unitary group

P
U
(
p
)

PU(p)

is determined by its mod 

p
p

cohomology as an unstable algebra over the Steenrod algebra for

p
>
3

p>3

, completing previous work by Dwyer, Miller and Wilkerson (1992) and Broto and Viruel (1998) for the cases

p
=
2
,
3

p=2,3

.
Hausdorff measures, dimensions and mutual singularity
Authors: Das Manav
Published: July 2005

Let

(
X
,
d
)

(X,d)

be a metric space. For a probability measure

μ
\mu

on a subset

E
E

of

X
X

and a Vitali cover

V
V

of

E
E

, we introduce the notion of a

b

μ

b_{\mu }

-Vitali subcover

V

μ

V_{\mu }

, and compare the Hausdorff measures of

E
E

with respect to these two collections. As an application, we consider graph directed self-similar measures

μ
\mu

and

ν
\nu

in

R

d

\mathbb {R}^{d}

satisfying the open set condition. Using the notion of pointwise local dimension of

μ
\mu

with respect to

ν
\nu

, we show how the Hausdorff dimension of some general multifractal sets may be computed using an appropriate stochastic process. As another application, we show that Olsen’s multifractal Hausdorff measures are mutually singular.
Isoform-selective Effects of the Depletion of ADP-Ribosylation Factors 1–5 on Membrane Traffic
Authors: Volpicelli-Daley Laura A. , Li Yawei , Zhang Chun-Jiang , Kahn Richard A.
Published: July 2005

The ADP-ribosylation factors (Arfs) are six proteins within the larger Arf family and Ras superfamily that regulate membrane traffic. Arfs all share numerous biochemical activities and have very similar specific activities. The use of dominant mutants and brefeldin A has been important to the discovery of the cellular functions of Arfs but lack specificity between Arf isoforms. We developed small interference RNA constructs capable of specific depletion of each of the cytoplasmic human Arfs to examine the specificity of Arfs in live cells. No single Arf was required for any step of membrane traffic examined in HeLa cells. However, every combination of the double knockdowns of Arf1, Arf3, Arf4, and Arf5 yielded a distinct pattern of defects in secretory and endocytic traffic, demonstrating clear specificity for Arfs at multiple steps. These results suggest that the cooperation of two Arfs at the same site may be a general feature of Arf signaling and provide candidates at several cellular locations that when paired with data on the localization of the many different Arf guanine nucleotide exchange factors, Arf GTPase activating proteins, and effectors will aid in the description of the mechanisms of specificity in this highly conserved and primordial family of regulatory GTPases.
Cell Polarity Protein Spa2P Associates With Proteins Involved In Actin Function InSaccharomyces Cerevisiae
Authors: Shih Judy L. , Reck-Peterson Samara L. , Newitt Rick , Mooseker Mark S. , Aebersold Ruedi , Herskowitz Ira
Published: July 2005

Spa2p is a nonessential protein that regulates yeast cell polarity. It localizes early to the presumptive bud site and remains at sites of growth throughout the cell cycle. To understand how Spa2p localization is regulated and to gain insight into its molecular function in cell polarity, we used a coimmunoprecipitation strategy followed by tandem mass spectrometry analysis to identify proteins that associate with Spa2p in vivo. We identified Myo1p, Myo2p, Pan1p, and the protein encoded by YFR016c as proteins that interact with Spa2p. Strikingly, all of these proteins are involved in cell polarity and/or actin function. Here we focus on the functional significance of the interactions of Spa2p with Myo2p and Myo1p. We find that localization of Spa2GFP to sites of polarized growth depends on functional Myo2p but not on Myo1p. We also find that Spa2p, like Myo2p, cosediments with F-actin in an ATP-sensitive manner. We hypothesize that Spa2p associates with actin via a direct or indirect interaction with Myo2p and that Spa2p may be involved in mediating polarized localization of polarity proteins via Myo2p. In addition, we observe an enhanced cell-separation defect in a myo1spa2 strain at 37°C. This provides further evidence that Spa2p is involved in cytokinesis and cell wall morphogenesis.
Myosin-Va Regulates Exocytosis through the Submicromolar Ca2+-dependent Binding of Syntaxin-1A
Authors: Watanabe Michitoshi , Nomura Kazushige , Ohyama Akihiro , Ishikawa Ryoki , Komiya Yoshiaki , Hosaka Kohei , Yamauchi Emiko , Taniguchi Hisaaki , Sasakawa Nobuyuki , Kumakura Konosuke , Ushiki Tatsuo , Sato Osamu , Ikebe Mitsuo , Igarashi Michihiro
Published: July 2005

Myosin-Va is an actin-based processive motor that conveys intracellular cargoes. Synaptic vesicles are one of the most important cargoes for myosin-Va, but the role of mammalian myosin-Va in secretion is less clear than for its yeast homologue, Myo2p. In the current studies, we show that myosin-Va on synaptic vesicles interacts with syntaxin-1A, a t-SNARE involved in exocytosis, at or above 0.3 μM Ca2+. Interference with formation of the syntaxin-1A–myosin–Va complex reduces the exocytotic frequency in chromaffin cells. Surprisingly, the syntaxin-1A-binding site was not in the tail of myosin-Va but rather in the neck, a region that contains calmodulin-binding IQ-motifs. Furthermore, we found that syntaxin-1A binding by myosin-Va in the presence of Ca2+depends on the release of calmodulin from the myosin-Va neck, allowing syntaxin-1A to occupy the vacant IQ-motif. Using an anti-myosin-Va neck antibody, which blocks this binding, we demonstrated that the step most important for the antibody's inhibitory activity is the late sustained phase, which is involved in supplying readily releasable vesicles. Our results demonstrate that the interaction between myosin-Va and syntaxin-1A is involved in exocytosis and suggest that the myosin-Va neck contributes not only to the large step size but also to the regulation of exocytosis by Ca2+.
Cross-Talk between Snurportin1 Subdomains
Authors: Ospina Jason K. , Gonsalvez Graydon B. , Bednenko Janna , Darzynkiewicz Edward , Gerace Larry , Matera A. Gregory
Published: July 2005

The initial steps of spliceosomal small nuclear ribonucleoprotein (snRNP) maturation take place in the cytoplasm. After formation of an Sm-core and a trimethylguanosine (TMG) cap, the RNPs are transported into the nucleus via the import adaptor snurportin1 (SPN) and the import receptor importin-β. To better understand this process, we identified SPN residues that are required to mediate interactions with TMG caps, importin-β, and the export receptor, exportin1 (Xpo1/Crm1). Mutation of a single arginine residue within the importin-β binding domain (IBB) disrupted the interaction with importin-β, but preserved the ability of SPN to bind Xpo1 or TMG caps. Nuclear transport assays showed that this IBB mutant is deficient for snRNP import but that import can be rescued by addition of purified survival of motor neurons (SMN) protein complexes. Conserved tryptophan residues outside of the IBB are required for TMG binding. However, SPN can be imported into the nucleus without cargo. Interestingly, SPN targets to Cajal bodies when U2 but not U1 snRNPs are imported as cargo. SPN also relocalizes to Cajal bodies upon treatment with leptomycin B. Finally, we uncovered an interaction between the N- and C-terminal domains of SPN, suggesting an autoregulatory function similar to that of importin-α.
Gα Subunit Gpa2 Recruits Kelch Repeat Subunits That Inhibit Receptor-G Protein Coupling during cAMP-induced Dimorphic Transitions inSaccharomyces cerevisiae
Authors: Harashima Toshiaki , Heitman Joseph
Published: July 2005

All eukaryotic cells sense extracellular stimuli and activate intracellular signaling cascades via G protein-coupled receptors (GPCR) and associated heterotrimeric G proteins. The Saccharomyces cerevisiae GPCR Gpr1 and associated Gα subunit Gpa2 sense extracellular carbon sources (including glucose) to govern filamentous growth. In contrast to conventional Gα subunits, Gpa2 forms an atypical G protein complex with the kelch repeat Gβ mimic proteins Gpb1 and Gpb2. Gpb1/2 negatively regulate cAMP signaling by inhibiting Gpa2 and an as yet unidentified target. Here we show that Gpa2 requires lipid modifications of its N-terminus for membrane localization but association with the Gpr1 receptor or Gpb1/2 subunits is dispensable for membrane targeting. Instead, Gpa2 promotes membrane localization of its associated Gβ mimic subunit Gpb2. We also show that the Gpa2 N-terminus binds both to Gpb2 and to the C-terminal tail of the Gpr1 receptor and that Gpb1/2 binding interferes with Gpr1 receptor coupling to Gpa2. Our studies invoke novel mechanisms involving GPCR-G protein modules that may be conserved in multicellular eukaryotes.