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BackgroundHigh levels of dietary sugar consumption may result in dysregulated glucose metabolism and lead to elevated cardiovascular disease risk via autonomic nervous system and cardiovascular dysfunction. Altered cardiovascular function can be examined using perturbation tasks such as mental challenge. This study examined the effects of controlled glucose intake on cardiovascular measures at rest and in responses to mental challenge in a laboratory setting.MethodUsing a double blind within-subjects design, participants were monitored at baseline, following ingestion of a glucose or taste-control solution, during structured speech (SS), anger recall (AR) and recovery (N = 24, 288 repeated measures; age = 21 ± 2 years). Pre-ejection period (PEP), heart rate (HR), stroke index (SI), cardiac index (CI), blood pressure and total peripheral resistance (TPR) were measured throughout the protocol.ResultsGlucose resulted in sustained decreased PEP levels compared to control condition (Δ = 11.98 ± 9.52 vs. 3.27 ± 7.65 m·s, P < .001) and transient increases in resting HR (P = .011), CI (P = .040) and systolic blood pressure (P = .009). Glucose did not result in increased cardiovascular reactivity to mental challenge tasks, but was associated with a delayed HR recovery following AR (P = .032).ConclusionGlucose intake resulted in a drop in PEP indicating increased sympathetic nervous system activity. No evidence was found for glucose-related exaggerated cardiovascular responses to mental challenge. Dysregulated glucose metabolism may result in elevated cardiovascular disease risk as a result of repeated glucose-induced elevations of sympathetic nervous system activity.Keywords: Glucose, Carbohydrate, Mental challenge, Cardiovascular reactivity, Cardiovascular recovery, Psychological distress

We report the results of an XMM-Newton observation of Sgr A East and its surroundings. The X-ray spectrum of Sgr A East is well represented with a two-temperature plasma model with temperatures of ~1 and ~4 keV. Only the iron abundance shows clear spatial variation; it concentrates in the core of Sgr A East. The derived plasma parameters suggest that Sgr A East originated in a single supernova. Around Sgr A East, there is a broad distribution of hard X-ray emission with a superimposed soft excess component extending away from the location of Sgr A East both above and below the plane. We discuss the nature of these structures as well as the close vicinity of Sgr A*., 7 pages, 3 figures, Accepted for publication in Advances in Space Research, as a proceeding paper for the 34th COSPAR E1.4 "High Energy Studies of Supernova Remnants and Neutron stars" held at Houston, Texas, USA during 10-19 Oct 2002; also found in http://www.star.le.ac.uk/~mas/research/paper/#Sakano2003cosp

Although considerable evidence attests to the hyperphagic effects of high-fat (HF) diets, the attribute(s) of these diets (e.g., palatability, caloric density, and postingestive effects) which promote overeating is still unclear. The present studies investigated the independent effects of diet palatability and macronutrient composition on intake using the self-regulated intragastric infusion paradigm. In Experiment 1, rats were infused with either HF or high-carbohydrate (HC) diet while drinking either saccharin (Sacc) or a more palatable saccharin–glucose (SaccGlu) test solution for 9 days. HF elicited greater daily intake than HC; lick pattern analysis revealed that HF produced larger but not more frequent bouts. Test solution was not related to intake, possibly due to the relatively modest palatability manipulation. Experiment 2 provided a more sensitive test: The palatability manipulation was strengthened and diet infusion made optional by provision of chow. HF again elicited larger bout size and total daily intake (diet+chow) than HC. Rats given the more palatable solution significantly increased intake (via larger bouts) and thus the amount of diet infused, but chow intake decreased such that total kilocalorie intake was not significantly related to solution palatability. The reliable observation that HF promoted larger bout size and greater total kilocalorie intake than HC provides additional evidence that fat sends weaker feedback signals relevant to controls of both satiation (suppression of ongoing eating, behaviorally manifest in meal size) and satiety (suppression of subsequent intake, reflected in total daily intake).

High-fat diets typically elicit greater kcal intake and/or weight gain than low-fat diets. Palatability, caloric density, and the unique postingestive effects of fat have each been shown to contribute to high-fat diet hyperphagia. Because long-term intake reflects the sum of many individual eating episodes (meals), it is important to investigate factors that may modulate fat intake at a meal. The present studies used high-fat (hi-fat) and high-carbohydrate (hi-carb) liquid diets (both 2.3 kcal/mL) to assess the effect of hunger level (0 versus 24-h food deprivation) and fat content of the maintenance diet (12 versus 48%) on fat preference (when a choice among foods is offered in a two-bottle test), and acceptance (only one food offered) in male rats. Preference for hi-fat relative to hi-carb (two-bottle test) was enhanced by 24-h food deprivation, and by a high-fat maintenance diet. In contrast, neither deprivation nor maintenance diet composition influenced relative meal size (one-bottle test) of hi-fat and hi-carb: irrespective of test conditions, meal size of hi-fat was bigger than meal size of hi-carb.

Hysteresis of dissolved calcium, silicon, nitrate, nitrite, ammonium and phosphorus fractions, i.e. soluble reactive phosphorus, total dissolved phosphorus and total phosphorus, in river waters during a major storm event in the R. Swale catchment in Yorkshire (U.K.), are quantified using a semi-empirical model. The model separates point and base-flow contributions of the chemical determinants from diffuse inputs. The magnitude of the diffuse inputs is related to river water discharge so that the size and rotation of the hysteresis loop is characterized by a single parameter. The approach is applied to chemical and water discharge data collected at 2 h intervals from three river sites in the catchment over a complete storm hydrograph. The results illustrate hysteresis effects for all the determinants with the majority showing “clockwise” hysteresis, i.e. higher concentrations during the rising limb of the hydrograph compared with those measured during the falling limb. The model parameters, computed by optimizing agreement between the predicted and measured concentration–discharge relationships, are generally consistent with land-use patterns in the catchment. The method has potential for further development to enable comparisons of chemical and nutrient dynamics in river catchments and the assessment of the relative importance of diffuse and point sources during high flow conditions.

Intensive monitoring of NGC 4151 showed strong, correlated variability at X-ray, ultraviolet, and optical wavelengths. The strongest variations were seen in ∼1.5 keV X-rays, with weaker variations at ∼100 keV and no significant variability in the 0.1–1 keV bands. In the ultraviolet/optical regime, the fractional variability amplitude decreased from 9% to 1% as the wavelength increased from 1275 A to 6900 A. The phase differences between variations in different bands were consistent with zero lag, with upper limits of ≲0.15 day between 1275 A and the other ultraviolet bands, ≲0.3 day between 1275 A and 1.5 keV, and ≲1 day between 1275 A and 5125 A, an order of magnitude improvement over limits determined in previous multi-waveband AGN monitoring campaigns. The ultraviolet fluctuation power spectra showed no evidence for periodicity, but were instead well-fitted with a very red power-law. The tight limits on the lags indicate that size of the putative reprocessing region is smaller than ∼0.15 lt-day in size. After correcting for absorption, the X-ray luminosity variations appear adequate to drive the ultraviolet/optical variations, but energy budget and other arguments indicate that only a fraction of the total low-energy flux could be reprocessed high-energy emission. The data are also consistent with the variable emission coming from the hotter inner regions of an accretion disk and non-variable emission from the cooler outer regions.

Warwick, Z. S., K. J. Bowen and S. J. Synowski. Learned suppression of intake based on anticipated calories: Cross-nutrient comparisons. Physiol Behav 62(6) 1319–1324, 1997.—Following training with distinctively flavored solutions which differ in calories and thus in their postingestive effects, rats demonstrate flavor–postingestive consequence learning by preferentially consuming one of the flavors in two-bottle tests (both flavors presented in nutrient-identical solutions). The direction of the preference—for the flavor previously paired with more calories (F-hi) or for the flavor previously paired with fewer calories (F-lo)—depends critically upon the magnitude of postingestive effects experienced during training. The most frequent and more thoroughly investigated observation has been preferential consumption of F-hi (conditioned flavor preference). However, when relatively concentrated solutions (e.g., 5% and 30% sucrose) are used as the training nutrients, F-lo is preferentially consumed in two-bottle tests. This lesser intake of F-hi presumably reflects its previous association with the more potent satiating effect of the highly concentrated nutrient: conditioned satiety. The present series of experiments explored conditioned satiety across nutrient types. In each experiment, rats consumed 30 mL of distinctively flavored nutritive solution per day, alternating between a distinctively flavored high-calorie (1.6 kcal/mL) solution and a lower calorie (0.2 kcal/mL) solution containing a different flavor. Two-bottle testing evaluated whether conditioned satiety was evident. Experiment 1 found that rats trained with sucrose, fructose, glucose, maltodextrin, or saccharin-sweetened medium-chain triglyceride oil emulsion preferentially consumed F-lo in two-bottle tests. In contrast, rats trained with corn oil emulsions tended to preferentially consume F-hi. In Experiment 2, increasing the number of corn oil calories associated with F-hi produced a tendency toward preferential intake of F-lo in two-bottle tests. In Experiment 3, rats consumed a high-fat maintenance diet; sucrose-trained rats again consumed more F-lo than F-hi, whereas rats trained with corn oil emulsions showed a tendency (nonsignificant) to consume more F-lo in two-bottle tests. In Experiment 4, however, adding saccharin to corn oil emulsions did produce conditioned satiety. These findings demonstrate conditioned satiety as a robust phenomenon across various nutrient types; however, corn oil calories entrain conditioned satiety only under certain conditions.

EXOSAT observations of the Seyfert galaxy NGC 4151 over the period July 1983 to April 1984 have revealed a decreasing flux in the 2 – 10 keV band. In accord with previous measurements a power law spectrum attenuated with a simple column of cold gas does not provide a satisfactory spectral fit below ~3 keV, where a lower relative opacity is required. Inclusion of additional low energy data from the EXOSAT telescopes allows the modelling of the absorbing column to be improved and reveals a second, separate, soft X-ray spectral component.

Catalogues of several types of extragalactic objects have been cross-correlated with Ginga measurements of the X-ray background intensity. Some of these catalogues give rise to significant signals, meaning that either sources in them or some other sources clustered around them produce a fraction of the X-ray background. The significance of these results has been established using bootstrap and X-ray background simulations. An expression to infer the local X-ray emissivity from the cross-correlation signal is given and applied to two galaxy catalogues (UGC and IRAS) for which the signal is more significant (>95 per cent). Values of ∼ 1039h ergs−1 Mpc−3 are obtained, implying that ≤ 30 per cent of the X-ray background could be produced by a non-evolving population of galaxies.

The BL Lacertae object OJ 287 was intensively monitored with the IUE satellite from 1993 March 15 to 20 in the 2000-3000 A wavelength region. The very low emission state of the source hampered the detection during part of the 23 performed exposures. The light curve at 2650 A constructed with the 11 best images exhibits a variable trend with a factor is less than or approximately 2 enhancement of the flux in about 3 hours. Simultaneous ground based observations show an optical flux variability of smaller amplitude, but correlated with the UV light curve without any apparent lag. The radio light curve is nearly constant. The UV emission state is the weakest observed in 15 years for this flaring blazard, being a factor of less than orapproximately 20 lower than the maximum recorded one.

Rats acquire a preference for a flavor paired with a caloric solution over a flavor paired with a solution providing fewer or no calories. Because the palatability and the caloric value of the solutions typically covary, it is unclear which property of the high-calorie solution reinforces the flavor preference. Two studies were conducted to assess the independent effects of palatability and calories in flavor preference conditioning. In Experiment 1, rats consumed two distinctively flavored solutions having equal palatability but different caloric value. The flavor paired with ingestion of more calories was subsequently preferred, indicating that a caloric advantage is sufficient to establish a flavor preference (flavor-calorie conditioning). In Experiment 2, rats consumed two distinctively flavored solutions having equal calories but different palatability. The flavor paired with the more palatable solution was subsequently preferred, indicating that a palatability advantage is sufficient to establish a flavor preference (flavor-flavor conditioning). This finding demonstrates flavor-flavor conditioning in the context of postingestive stimulation by calories. Taken together, these results demonstrate both flavor-calorie and flavor-flavor conditioning in the context of normal ingestion (i.e., self-paced oral intake of nutritive solutions).

Repeated exposure to a tastant often leads to a decrease in magnitude of the perceived intensity; this phenomenon is termed adaptation. The purpose of this study was to determine the degree of adaptation of the sweet response for a variety of sweeteners in water and in the presence of two levels of tannic acid. Sweetness intensity ratings were given by a trained panel for 14 sweeteners: three sugars (fructose, glucose, sucrose), two polyhydric alcohols (mannitol, sorbitol), two terpenoid glycosides (rebaudioside-A, stevioside), two dipeptide derivatives (alitame, aspartame), one sulfamate (sodium cyclamate), one protein (thaumatin), two N-sulfonyl amides (acesulfame-K, sodium saccharin), and one dihydrochalcone (neohesperidin dihydrochalcone). Panelists were given four isointense concentrations of each sweetener by itself and in the presence of two concentrations of tannic acid. Each sweetener concentration was tasted and rated four consecutive times with a 30 s interval between each taste and a 2 min interval between each concentration. Within a taste session, a series of concentrations of a given sweetener was presented in ascending order of magnitude. Adaptation was calculated as the decrease in intensity from the first to the fourth sample. The greatest adaptation in water solutions was found for acesulfame-K, Na saccharin, rebaudioside-A, and stevioside. This was followed by the dipeptide sweeteners, alitame and aspartame. The least adaptation occurred with the sugars, polyhydric alcohols, and neohesperidin dihydrochalcone. Adaptation was greater in tannic acid solutions than in water for six sweeteners. Adaptation of sweet taste may result from the desensitization of sweetener receptors analogous to the homologous desensitization found in the beta adrenergic system.

This paper reviews the literature on the role of dietary fat in calorie intake and body weight gain in humans and laboratory animals. An overview of 40 animal studies which compared growth on high-fat (HF) and high-carbohydrate (HC) solid/powdered diets indicated that the HF diet elicited greater weight gain in 33 out of 40 studies. Enhanced growth on the HF diet was often, but not exclusively, attributable to greater caloric intake. Additional evidence for the growth-enhancing effect of HF diets emerges from "diet option" and "supermarket" feeding studies in rats, and experimental and epidemiological studies in humans. Three principal factors that contribute to the different responses to HF and HC diets are (a) caloric density, (b) sensory properties and palatability, and (c) postabsorptive processing. It is concluded that both calorie intake and metabolic energy expenditure are biased towards weight gain when a HF diet is consumed, and that the high caloric density of high-fat diets plays a primary role in weight gain. Humans may be biologically predisposed to gain weight when a HF diet is consumed.

A diverse array of chemicals has been proposed as control agents for the destructive, biofouling bivalve, Dreissena polymorpha , commonly known as the zebra mussel. The zebra mussel has caused great economic hardship in industries situated on Lake Erie due to its proclivity for fouling the inside of water intake pipes and blocking the flow of water. The mussel also has had a significant ecological impact by consuming huge amounts of phytoplankton. Because the water in which zebra mussels reside may ultimately be consumed by humans and because protection of commercial fish is as important as controlling the zebra mussels, control methods must distinguish between desirable species and the zebra mussels. Most of the currently available molluscicides do not. However, we report that environmentally innocuous derivatives of potassium (e.g. KH 2 PO 4 and KCl) can kill zebra mussels at relatively low concentrations without affecting most nontarget organisms. Potassium phosphate is efficacious in killing the zebra mussels across a range of environmental conditions. Potassium chloride or other potassium salts may be used as a substitute when ambient calcium levels in the water result in the formation of a water insoluble precipitate upon combining with dissociated phosphate. Potassium appears to kill the mussels by destroying the integrity of the mussels' gill epithelium, which leads to asphyxiation.

The fate of pentachlorophenol in aquatic microcosms, consisting of three trophic levels and held under varying conditions of pH and sediment type, was assessed. The pH was set at 4, 6, or 8, with an organic sediment (3% organic carbon) or an inorganic sediment (0% organic carbon) as a substrate. The distribution of PCP in the microcosm media and organisms varied significantly as environmental conditions changed. There was significantly more PCP (or phenate ion) in the water at pH 8 than pH 6 or 4 in both the organic and inorganic systems. However, accumulation of PCP in most of the microcosm organisms was significantly greater at pH 4, followed by 6 and then 8. Partitioning of PCP into organic sediment followed the same trend with the highest amounts of PCP appearing in sediment at pH 4. The organic carbon content of sediment was important in determining partitioning into sediment; the 3% organic carbon sediment sorbed significantly more PCP than the 0% organic carbon sediment. In addition, the organisms in the 3% organic carbon sediment microcosms accumulated significantly less PCP then did those in the 0% organic carbon systems. The 3% organic carbon sediment also appeared to facilitate the breakdown of PCP in sediment and water. Among others these data indicate that hazard assessments should not be based on aqueous levels of PCP unless pH is considered.

Weanling rats were fed either a high-fat (30% of calories) or a low-fat (10% of calories) diet four weeks, after which fat preference was assessed using a choice paradigm. Fat preference was measured during 2-hour intake tests in which three peanut butter/peanut oil mixtures containing 0.50, 0.61, and 0.71 grams fat/gram were offered to each animal. Rats fed the high-fat (HF) diet preferred the highest-fat mixture and consumed more total fat during intake tests than animals fed the low-fat (LF) diet. Intake of NaCl and sucrose solutions was measured during separate intake tests. LF-fed rats drank more NaCl solution than HF-fed rats. Following these tests a subgroup of the LF-fed animals was fed the HF diet, and a subgroup of the HF-fed group was fed the LF diet for a further four weeks. Upon repetition of the intake tests, rats that had been fed the HF diet during the intitial four weeks still preferred the highest-fat mixture.

Young (mean age 22.4 years) and elderly (mean age 82.3 years) subjects tasted and rated a range of liquids containing between 0.5% and 36% dairy fat by weight. The liquids also contained either sucrose (0-20%) or NaCl (0-0.584%). Within each age group both normal weight and overweight subjects participated. The fat content in the mixtures was unrelated to pleasantness ratings for elderly subjects. The concentrations of both fat and sucrose in the mixtures determined the hedonic responses of young normal weight subjects. Overweight young subjects' hedonic responses were predominantly influenced by sucrose concentration. Fat content in dairy-salt mixtures was significantly related to pleasantness ratings by young subjects, but did not influence ratings by elderly subjects. These findings suggest that the elderly can significantly reduce dietary fat intake without sacrificing perceived pleasantness.

Significant losses in the ability to detect the taste of glutamic acid and to recognize odorants were found in demented patients when compared with age-matched controls. These losses were not specific to patients with Alzheimer's disease (AD) but were also found in demented patients without AD. Detection thresholds for bitter-tasting quinine HCl were not higher in demented patients than in age-matched controls but were higher than thresholds in young subjects. These data suggest that losses in taste in demented patients may vary with the chemical structure of the tastant. The degree of loss in the ability to recognize odorants was greater in patients with a family history of senile dementia.

The simultaneous effects of pH and temperature upon the aquatic toxicity of carbaryl were determined in acute toxicity tests, uptake studies, and residue studies. Toxicity tests were conducted with fourth instar midge larvae, Chironomus riparius , in water held at pH values 4, 6 and 8 and at temperatures of 10°C, 20°C and 30°C. The toxicity of carbaryl varied significantly with changing pH and temperature. An increase in temperature from 10°C to 30°C at pH 4 resulted in a 2-fold increase in toxicity and a corresponding decrease in EC 50 values (133 μg/l to 61 μg/l). The same increase in temperature at pH 6 resulted in a similar increase in toxicity (133 μg/l to 71 μg/l). Increasing temperature at pH 8 caused first a decrease (96 μg/l to 128 μg/l), then an increase (128 μg/l to 107 μg/l) in toxicity. Toxicity was highest at pH 4, 30° C and lowest at pH values 4 and 6, 10°C. There was no significant difference in toxicity at pH 4 and 6 at any tested temperature. Uptake of 14 C-carbaryl by midge larvae was generally correlated with toxicity although exceptions were noted. Significantly more total radioactivity was absorbed by the midge larvae at pH 8 than at pH 6 or 4 at both 20°C and 30°C. The stability of carbaryl in water was enhanced by low pH and low temperature with 94% remaining after 24 h at pH 4, 10°C. Only 23% remained after 24 h at pH 8, 30°C. As water chemistry parameters changed, so too did the biological manifestations of carbaryl bioavailability such as acute toxicity and uptake by aquatic organisms. These manifestations are different than results based upon the individual influences of water chemistry parameters.

We present a physical interpretation of the the dramatic spectral variability observed in the XUV band of the X-ray bright BL Lac type object Markarian 421 (Mrk421). We show that a conical relativistic jet model can adequately explain the data if the upper cut-off in the synchrotron emitting electron population has a variable radial dependence. The physical parameters in the region of the jet responsible for the bulk of the X-ray emission in Mrk421 are derived in the context of such a model.

The environmental fate of [14C]fenitrothion was evaluated in aquatic microcosms held at pH 8.3 or 6.7. No general effect attributable to pH was observed; however, several significant interactions were identified. Of these, the findings that statistically higher amounts of radioactivity were present in water held at pH 6.7 and that significantly less metabolism of the parent compound occurred in the organisms at pH 8.3 were preeminent. These differences seen in metabolism and environmental fate between pH values are relatively minor and do not compromise the safety of the compound.

Superposed epoch analysis of geomagnetic index around day of occurrence of large central flares shows a significant increase in geomagnetic activity following flares selected according to: 1. (a) area of the flare 2. (b) “importance” of the flare. The association does not extend to flares of lesser importance, 2. During the period 1950–1954, near sunspot minimum and roughly the same period studied by Watson, there was no tendency for geomagnetic disturbance to follow within 2–3 days after the fourteen reported class 3 and 3+ flares.

Impairment of the senses of taste and smell is one of the major factors contributing to anorexia in the elderly. Anorexia often remits when foods are amplified by additional odor to compensate for diminished chemosensory functioning.