Contextual control over conditioned responding in an extinction paradigm.

Four experiments studied contextual control over rats' freezing to conditioned stimuli (CSs) that had been paired with shock and were then extinguished. In Experiment 1, rats were exposed to a CS A–shock and a CS B–shock pairing in Context C. CS A was then extinguished in Context A, and CS B in Context B. Freezing was renewed when each CS was presented in the context where the other CS had been extinguished. In Experiments 2–4, rats were exposed to a CS A–shock pairing in A and a CS B–shock pairing in B. They were then exposed to Context C where one, both, or neither of the CSs were extinguished, or where both CSs continued to be reinforced. On test, the rats froze more to CS A than to CS B in Context A, and more to CS B than to CS A in Context B, but only if the CSs had been extinguished. Thus, after extinction, rats use contexts to regulate retrieval not only of their memory for extinction, but also of their memory for the original conditioning episode. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multilayer film preparation of poly(4-vinylphenol) from aqueous media

The use of weak polyelectrolytes in multilayer polymer systems provides a means of altering the physico-chemical properties of these thin films. This paper examines the limits of the polyanions by incorporating the extremely weak polyelectrolyte, poly(4-vinylphenol) (PVPh), into a multilayer system with poly(allylamine hydrochloride) (PAH) from a dilute aqueous media. Film growth was monitored using absorption spectroscopy and revealed a clear linear trend in film thickness. The surface morphology, thickness, and swelling of the multilayer films systems were examined using atomic force microscopy (AFM). Film thickness greatly depended upon the pH of the polymer precursor solutions; 50-layer systems created at pH 12.5 and 11.0 were 8.2 and 246.6 nm thick, respectively, a difference of over 2900%. This is the first report on the incorporation of PVPh into a multilayer system from an aqueous media.     

3-Deoxyschweinfurthin B Lowers Cholesterol Levels by Decreasing Synthesis and Increasing Export in Cultured Cancer Cell Lines

The schweinfurthins have potent antiproliferative activity in multiple glioblastoma multiforme (GBM) cell lines; however, the mechanism by which growth is impeded is not fully understood. Previously, we demonstrated that the schweinfurthins reduce the level of key isoprenoid intermediates in the cholesterol biosynthetic pathway. Herein, we describe the effects of the schweinfurthins on cholesterol homeostasis. Intracellular cholesterol levels are greatly reduced in cells incubated with 3‐deoxyschweinfurthin B (3dSB), an analog of the natural product schweinfurthin B. Decreased cholesterol levels are due to decreased cholesterol synthesis and increased cholesterol efflux; both of these cellular actions can be influenced by liver X‐receptor (LXR) activation. The effects of 3dSB on ATP‐binding cassette transporter 1 levels and other LXR targets are similar to that of 25‐hydroxycholesterol, an LXR agonist. Unlike 25‐hydroxycholesterol, 3dSB does not act as a direct agonist for LXR α or β. These data suggest that cholesterol homeostasis plays a significant role in the growth inhibitory activity of the schweinfurthins and may elucidate a mechanism that can be targeted in human cancers such as GBM.     

Effect of Ambrotose AO<Superscript>®</Superscript> on resting and exercise-induced antioxidant capacity and oxidative stress in healthy adults

Background

The purpose of this investigation was to determine the effects of a dietary supplement (Ambrotose AO^®) on resting and exercise-induced blood antioxidant capacity and oxidative stress in exercise-trained and untrained men and women.

Methods

25 individuals (7 trained and 5 untrained men; 7 trained and 6 untrained women) received Ambrotose AO^® (4 capsules per day = 2 grams per day) or a placebo for 3 weeks in a random order, double blind cross-over design (with a 3 week washout period). Blood samples were collected at rest, and at 0 and 30 minutes following a graded exercise treadmill test (GXT) performed to exhaustion, both before and after each 3 week supplementation period. Samples were analyzed for Trolox Equivalent Antioxidant Capacity (TEAC), Oxygen Radical Absorbance Capacity (ORAC), malondialdehyde (MDA), hydrogen peroxide (H₂O₂), and nitrate/nitrite (NOx). Quality of life was assessed using the SF-12 form and exercise time to exhaustion was recorded. Resting blood samples were analyzed for complete blood count (CBC), metabolic panel, and lipid panel before and after each 3 week supplementation period. Dietary intake during the week before each exercise test was recorded.

Results

No condition effects were noted for SF-12 data, for GXT time to exhaustion, or for any variable within the CBC, metabolic panel, or lipid panel (p > 0.05). Treatment with Ambrotose AO^® resulted in an increase in resting levels of TEAC (p = 0.02) and ORAC (p < 0.0001). No significant change was noted in resting levels of MDA, H₂O₂, or NOx (p > 0.05). Exercise resulted in an acute increase in TEAC, MDA, and H₂O₂ (p < 0.05), all which were higher at 0 minutes post exercise compared to pre exercise (p < 0.05). No condition effects were noted for exercise related data (p > 0.05), with the exception of ORAC (p = 0.0005) which was greater at 30 minutes post exercise for Ambrotose AO^® compared to placebo.

Conclusion

Ambrotose AO^® at a daily dosage of 4 capsules per day increases resting blood antioxidant capacity and may enhance post exercise antioxidant capacity. However, no statistically detected difference is observed in resting or exercise-induced oxidative stress biomarkers, in quality of life, or in GXT time to exhaustion.

     

Evaluating the impacts of membrane type, coating, fouling, chemical properties and water chemistry on reverse osmosis rejection of seven nitrosoalklyamines, including NDMA

Reverse osmosis (RO) treatment has been found to be effective for a wide range of organics but generally small, polar, uncharged molecules such as N-nitrosodimethylamine (NDMA) can be poorly rejected. The rejection of seven N-nitrosoalkylamines with molecular masses in the range of 78-158Da, including NDMA, N-nitrosodiethylamine (NDEA), N-nitrosomethylethylamine (NMEA), N-nitrosodipropylamine (NDPA), N-nitrosodibutylamine (NDBA), N-nitrosopyrrolidine (NPyr), N-nitrosopiperidine (NPip) by three commercial brackish-water reverse osmosis membranes was studied in flat-sheet cells under cross-flow conditions. The membranes used were ESPA3 (Hydranautics), LFC3 (Hydranautics) and BW-30 (Dow/Filmtec), commonly used in water reuse applications. The effects of varying ionic strength and pH, dip-coating membranes with PEBAX 1657, a hydrophilic polymer, and artificial fouling with alginate on nitrosamine rejection were quantified. Rejection in deionized (DI) water increased with molecular mass from 56 to 70% for NDMA, to 80-91% for NMEA, 89-97% for NPyr, 92-98% for NDEA, and to beyond the detection limits for NPip, NDPA and NDBA. For the nitrosamines with quantifiable transmission, linear correlations (r(2)>0.97) were found between the number of methyl groups and the log(transmission), with factor 0.35 to 0.55 decreases in transmission per added methyl group. A PEBAX coating lowered the ESPA3 rejection of NDMA by 11% but increased the LFC3 and BW30 rejection by 6% and 15%, respectively. Artificially fouling ESPA3 membrane coupons with 170g/m(2) alginate decreased the rejection of NDMA by 18%. A feed concentration of 100mM NaCl decreased rejection of NDMA by 15% and acidifying the DI water feed to pH=3 decreased the rejection by 5%, whereas increasing the pH to 10 did not have a significant (p<0.05) effect.     

Coke yield and heat transfer in reaction of liquid–solid agglomerates of Athabasca vacuum residue

The ultimate coke yield was determined for agglomerates of Athabasca vacuum residue and coke particles by heating on Curie‐point alloy strips in an induction furnace at 503 and 530°C until all toluene‐soluble material was converted. Coke yield results from agglomerates were compared to the coke yield results from reacting thin films of vacuum residue. The average coke yield from the agglomerates was 23%, while the coke yield from thin films of 20 µm thickness was 11%, which supports the role of mass transfer in coke formation reactions. The ultimate coke yield was insensitive to vacuum residue concentration, agglomerate size, and reaction temperature. The temperature profile within agglomerates was measured by implanting a thermocouple, and a simple heat transfer model was used to describe the temperature variation with time. The effective thermal diffusivity of the agglomerates was 0.20 × 10^?6 m²/s. Control experiments on reaction in thin liquid films confirmed that heating rates in the range of 14.8–148 K/s had no effect on the ultimate yield of coke yield.     

Fluorescent THF‐Based Fructose Analogue Exhibits Fructose‐Dependent Uptake

Recent publications suggest that high dietary fructose might play a significant role in cancer metabolism and can exacerbate a number of aspects of metabolic syndrome. Addressing the role that fructose plays in human health is a controversial question and requires a detailed understanding of many factors including the mechanism of fructose transport into healthy and diseased cells. Fructose transport into cells is thought to be largely mediated by the passive hexose transporters Glut2 and Glut5. To date, no probes that can be selectively transported by one of these enzymes but not by the other have been identified. The data presented here indicate that, in MCF‐7 cells, a 1‐amino‐2,5‐anhydro‐D ‐mannitol‐based fluorescent NBDM probe is transported twice as efficiently as fructose and that this takes place with the aid of Glut5. Its Glut5 specificity and differential uptake in cancer cells and in normal cells suggest this NBDM probe as a potentially useful tool for cross‐cell‐line correlation of Glut5 transport activity.     

A Multiple Motives Approach to Tobacco Dependence: The Wisconsin Inventory of Smoking Dependence Motives (WISDM-68).

The dependence construct fills an important explanatory role in motivational accounts of smoking and relapse. Frequently used measures of dependence are either atheoretical or grounded in a unidimensional model of physical dependence. This research creates a multidimensional measure of dependence that is based on theoretically grounded motives for drug use and is intended to reflect mechanisms underlying dependence. Data collected from a large sample of smokers (N = 775) indicated that all 13 subscales of the Wisconsin Inventory of Smoking Dependence Motives (WISDM-68) have acceptable internal consistency, are differentially present across levels of smoking heaviness, and have a multidimensional structure. Validity analyses indicated the WISDM-68 subscales are significantly related to dependence criteria such as smoking heaviness and to 4th edition Diagnostic and Statistical Manual of Mental Disorders symptoms of dependence and relapse. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Longitudinal prediction of child outcomes from differing measures of parenting in a low-income sample.

This study examined predictions from preschool parenting measures to middle childhood cognitive and socioemotional child outcomes to explore whether parenting assessment methodologies that require more time, training, and expense yield better predictions of child outcomes than less intensive methodologies. Mother-child dyads (N=278) in low-income African American families were assessed when the child was in preschool, using maternal report, the Home Observation for Measurement of the Environment-Short Form (P. Baker & F. Mott, 1989; R. Bradley & B. Caldwell, 1984), and structured observational measures of parenting. Child outcomes reported by children, mothers, teachers, and direct assessment were collected 4 years later. All parenting methodologies showed some predictive value; however, observational parenting measures showed the strongest and most consistent predictions of child outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)