Sperm Limitation Produces Male Biased Offspring Sex Ratios in the Wasp, Nasonia vitripennis (Hymenoptera: Pteromalidae).

Haplo-diploid sex determination in the parasitoid wasp, Nasonia vitripennis (Walker), allows females to adjust their brood sex ratios. Females influence whether ova are fertilized, producing diploid females, or remain unfertilized, producing haploid males. Females appear to adjust their brood sex ratios to minimize 'local mate competition,' i.e., competition among sons for mates. Because mating occurs between siblings, females may optimize mating opportunities for their offspring by producing only enough sons to inseminate daughters when ovipositing alone, and producing more sons when superparasitism is likely. Although widely accepted, this hypothesis makes no assumptions about gamete limitation in either sex. Because sperm are used to produce daughters, repeated oviposition could reduce sperm supplies, causing females to produce more sons. In contrast, if egg-limited females produce smaller broods, they might use fewer sperm, making sperm limitation less likely. To investigate whether repeated oviposition and female fertility influence gamete limitation within females, we created two treatments of six mated female wasps, which each received a series of six hosts at intervals of 24 or 48 h. All females produced at least one mixed-sex brood (63 total broods; 3,696 offspring). As expected, if females became sperm-limited, in both treatments, brood sex ratios became increasingly male-biased with increasing host number. Interhost interval did not affect brood size, total offspring number, or sex ratio, indicating females did not become egg limited. Our results support earlier studies showing sperm depletion affects sex allocation in N. vitripennis¸ and could limit adaptive sex ratio manipulation in these parasitoid wasps.

Large-area high-quality graphene on Ge(001)/Si(001) substrates.

Various experimental data revealing large-area high-quality graphene films grown by the CVD method on Ge(001)/Si(001) substrates are presented. SEM images have shown that the structure of nano-facets is formed on the entire surface of Ge(001), which is covered by a graphene layer over the whole macroscopic sample surface of 1 cm(2). The hill-and-valley structures are positioned 90° to each other and run along the <100> direction. The hill height in relation to the valley measured by STM is about 10 nm. Raman measurements have shown that a uniform graphene monolayer covers the nano-facet structures on the Ge(001) surface. Raman spectroscopy has also proved that the grown graphene monolayer is characterized by small strain variations and minimal charge fluctuations. Atomically resolved STM images on the hills of the nanostructures on the Ge(001) surface have confirmed the presence of a graphene monolayer. In addition, the STS/CITS maps show that high-quality graphene has been obtained on such terraces. The subsequent coalescence of graphene domains has led to a relatively well-oriented large-area layer. This is confirmed by LEED measurements, which have indicated that two orientations are preferable in the grown large-area graphene monolayer. The presence of large-area coverage by graphene has been also confirmed by low temperature Hall measurements of a macroscopic sample, showing an n-type concentration of 9.3 × 10(12) cm(-2) and a mobility of 2500 cm(2) V(-1) s(-1). These important characteristic features of graphene indicate a high homogeneity of the layer grown on the large area Ge(001)/Si(001) substrates.

SEM and Raman analysis of graphene on SiC(0001).

Graphene grown by a sublimation technique was studied by Scanning Electron Microscopy (SEM) and micro-Raman spectroscopy. The measurement area of a sample was marked and investigated using both systems, as a result of which SEM images were directly compared with Raman maps. In this work we show that a correlative analysis of Energy Selective Backscattered electrons detector (EsB), In-Lens figures and Raman maps of shape and intensity of the 2D band is adequate to determine graphene layer thickness with the precision of SEM and reliability of Raman spectroscopy.

Obesity status transitions across the elementary years: use of Markov chain modelling.

OBJECTIVE: The objective of this study was to assess overweight and obesity status transition probabilities using first-order Markov transition models applied to elementary school children. METHOD: Complete longitudinal data across 11 assessments were available from 1494 elementary school children (from 7599 students in 41 out of 45 schools in a Southeast Texas school district) from kindergarten to the beginning of the fifth grade. Heights and weights were measured by trained school nurses using standard procedures at the beginning and end of each school year for the 11 consecutive assessments. To estimate the transition probabilities, first-order three-state (healthy weight, overweight and obese) Markov transition models were fit to the longitudinal weight status data of all assessment periods. RESULTS: While there was a gradual shift to more children in the overweight or obese category over 5 years, children were most likely to stay in the same weight category as the previous assessment. A consistent seasonal difference in the probability of changing weight status category was seen, with a greater probability of becoming overweight and obese during the summer compared with the school year. The transition probabilities to obesity were higher among boys, Hispanic and non-Hispanic Black, and lower socioeconomic status children. CONCLUSIONS: This study provides the first application of a Markov transition model to child weight status data. The transitions into the overweight and obese categories were small, but persistent, with smaller percentages transitioning out of overweight or obese. Early monitoring and summer intervention strategies are needed to prevent the slow, but relentless, transition into the overweight and obese categories.

How to engage children in self-administered dietary assessment programmes.

Effectively assessing children's dietary intake is essential for understanding the complex relationships among dietary behaviours and obesity. Dietary assessment accuracy decreases when children are unable or unmotivated to complete accurate self-reports. Technology-based assessment instruments for children's self-report of diet can be enhanced in light of developments in media psychology and communication science. To motivate children to complete a dietary assessment, researchers could use animated, customisable agents; embed the assessment process into a video game; or add narratives to encourage self-reporting behaviour. To improve accuracy, the intake environment could be recreated virtually; training sessions could be interspersed to improve portion estimation; and implicit attitudinal measures could be incorporated as a control or to increase validity. Research is needed to evaluate possible methods of enhancing children's self-reporting motivation and accuracy. The main challenge remains how to engage children without biasing their reporting.

Food Intake Recording Software System, version 4 (FIRSSt4): a self-completed 24-h dietary recall for children.

The Food Intake Recording Software System, version 4 (firsst4), is a web-based 24-h dietary recall (24 hdr) self-administered by children based on the Automated Self-Administered 24-h recall (ASA24) (a self-administered 24 hdr for adults). The food choices in firsst4 are abbreviated to include only those reported by children in US national surveys; and detailed food probe questions are simplified to exclude those that children could not be expected to answer (e.g. questions regarding food preparation and added fats). ASA24 and firsst4 incorporate 10 000+ food images, with up to eight images per food, to assist in portion size estimation. We review the formative research conducted during the development of firsst4. When completed, firsst4 will be hosted and maintained for investigator use on the National Cancer Institute's ASA24 website.

Graphene epitaxy by chemical vapor deposition on SiC.

We demonstrate the growth of high quality graphene layers by chemical vapor deposition (CVD) on insulating and conductive SiC substrates. This method provides key advantages over the well-developed epitaxial graphene growth by Si sublimation that has been known for decades. (1) CVD growth is much less sensitive to SiC surface defects resulting in high electron mobilities of ∼1800 cm(2)/(V s) and enables the controlled synthesis of a determined number of graphene layers with a defined doping level. The high quality of graphene is evidenced by a unique combination of angle-resolved photoemission spectroscopy, Raman spectroscopy, transport measurements, scanning tunneling microscopy and ellipsometry. Our measurements indicate that CVD grown graphene is under less compressive strain than its epitaxial counterpart and confirms the existence of an electronic energy band gap. These features are essential for future applications of graphene electronics based on wafer scale graphene growth.

In vitro and in vivo characterization of A-940894: a potent histamine H4 receptor antagonist with anti-inflammatory properties.

BACKGROUND AND PURPOSE: The histamine H4 receptor is widely expressed in cells of immune origin and has been shown to play a role in a variety of inflammatory processes mediated by histamine. In this report, we describe the in vitro and in vivo anti-inflammatory properties of a potent histamine H4 receptor antagonist, A-940894 (4-piperazin-1-yl-6,7-dihydro-5H-benzo[6,7]cyclohepta[1,2-d]pyrimidin-2-ylamine). EXPERIMENTAL APPROACH: We have analysed the pharmacological profile of A-940894 at mouse native, rat recombinant and human recombinant and native, histamine H4 receptors by radioligand binding, calcium mobilization, mast cell shape change, eosinophil chemotaxis assays and in the mouse model of zymosan-induced peritonitis. KEY RESULTS: A-940894 potently binds to both human and rat histamine H4 receptors and exhibits considerably lower affinity for the human histamine H1, H2 or H3 receptors. It potently blocked histamine-evoked calcium mobilization in the fluorometric imaging plate reader assays and inhibited histamine-induced shape change of mouse bone marrow-derived mast cells and chemotaxis of human eosinophils in vitro. In a mouse mast cell-dependent model of zymosan-induced peritonitis, A-940894 significantly blocked neutrophil influx and reduced intraperitoneal prostaglandin D2 levels. Finally, A-940894 has good pharmacokinetic properties, including half-life and oral bioavailability in rats and mice. CONCLUSIONS AND IMPLICATIONS: These data suggest that A-940894 is a potent and selective histamine H4 receptor antagonist with pharmacokinetic properties suitable for long-term in vivo testing and could serve as a useful tool for the further characterization of histamine H4 receptor pharmacology.

BMI from 3-6 y of age is predicted by TV viewing and physical activity, not diet.

OBJECTIVE: To investigate whether, diet, physical activity, sedentary behavior or television (TV) viewing predicted body mass index (BMI) among 3-7-y-old children. DESIGN: A triethnic cohort of 3-4-y-old children was followed for 3 y from 1986 to 1989. MEASUREMENTS: BMI was assessed at the beginning and end of each measurement year. Heart rate monitoring and observation were used to assess physical activity. Diet (calories, % calories from fat and carbohydrate), sedentary behavior and TV viewing were assessed by direct observation in each year. A repeated measures regression analysis with year as a factor and BMI at the end of each year as dependent variables was run. Nonsignificant variables were removed in a stepwise backward deletion process and significant interactions graphed. RESULTS: The interactions between minutes of TV viewing per hour and study year and minutes of physical activity per hour and study year were significant (P<0.05). There were also significant main effects for TV viewing, physical activity and BMI from the beginning of the study. The model accounted for 65% of the variance in BMI across the three study years. Plotting the significant interactions demonstrated that physical activity was positively associated with BMI in year 1, and negatively associated in years 2 and 3 with a stronger negative relationship in year 3 than 2. TV viewing became positively associated with BMI during the third study year. CONCLUSION: Physical activity and TV viewing were the only significant predictors (other than baseline BMI) of BMI among a triethnic cohort of 3-4-y-old children followed for 3 y with both physical activity (negatively associated) and TV viewing (positively associated) becoming stronger predictors as the children aged. It appears that 6 or 7 y is a critical age when TV viewing and physical activity may affect BMI. Therefore, focusing on reducing time spent watching television and increasing time spent in physical activity may be successful means of preventing obesity among this age group.

Fine structure of effective mass acceptors in gallium nitride.

Magnetoluminescence of the exciton bound to a neutral acceptor was measured to investigate the electronic structure of a shallow acceptor center in GaN. The application of magnetic fields along different directions with respect to the crystal c axis allowed us to determine the symmetry of the ground (Gamma(9)) and the first excited state (Gamma(7)) of the acceptor. The observed Zeeman splitting pattern has axial symmetry but can be explained well only by assuming a significant reduction of the spin-orbit interaction for this acceptor state. Because of this reduction, the energy structure of the neutral acceptor is found to be very sensitive to any local, axial perturbation.

Postinfarction ventricular septal defect closure with Amplatzer occluders.

OBJECTIVE: Postinfarction ventricular septal defect (PIVSD) is a rare and life-threatening complication with high risk of both surgical and medical treatment. Another option available now is transcatheter closure. The purpose of this paper is to report the results of such treatment with Amplatzer occluders. METHOD: Seven patients aged from 51 to 71 years were included. The procedure was performed between 2 and 10 weeks after myocardial infarction. One patient had double residual VSD (2 months after previous surgery) and another, coexisting critical stenosis of right coronary artery (RCA). All patients were in III/IV NYHA class, on intropes, one patient on aortic balloon counterpulsation. Venous jugular approach was used to close the VSD in six patients, venous transfemoral in one patient. Implantation of six Ampaltzer atrial septal occluders (ASO) and one muscular Amplatzer VSD occluder (VSO) were performed. RESULTS: All procedures but two were finished successfully. In one patient, the defect could not be entered neither from the venous nor the arterial side due to unusual oblique course (which was confirmed during subsequent operation). In the second patient (2 weeks after MI), the reason was unstable position of 24 mm ASO (probably due to necrotic borders of VSD). Immediate significant clinical improvement was achieved in all patients, in whom PIVSD was closed with Amplatzer occluders. In one postsurgical patient, two ASO were used; in another patient, prior to VSD closure, PTCA and stent implantation to RCA was performed. The stretched diameter of PIVSD ranged from 8 to 22 mm, the size of implanted Amplatzer occluders from 12 to 24 mm. Fluoroscopy time was 60 min (18-120). During the procedure, ventricular fibrillation requiring defibrillation was observed in three patients. One patient died 1 week after the procedure because of multiorgan failure and increasing mitral incompetence (MI). CONCLUSIONS: Despite some technical problems, implantation of Amplatzer occluders, is an attractive option of treatment of patients with subacute PIVSD.

Dosimetry of low energy ions by means of solid state nuclear track detectors.

This paper concerns applications of solid state nuclear track detectors (SSNTDs) of the CR-39 type for measurements of ion streams emitted from the rod plasma injector (RPI). The main diagnostic tool was a Thomson-type mass spectrometer, To detect low energy ions use was made of an additional ion-acceleration system, which enabled the registration threshold to be lowered to about 25 keV. Simultaneously with the time-integrated measurements, time-resolved studies were performed of ion streams by means of Faraday-type collectors. It was shown that the investigated plasma-ion source generates also high energy ions, e.g. protons of energy of 2.6-3.7 MeV. For the analysis of the irradiated and etched CR-39 detectors use was made of a computerised system, which enabled determination of the dimensions of the registered tracks produced by low energy protons, deuterons and nitrogen ions. It has extended the known characteristics of the CR-39 detector.

Family and child-care provider influences on preschool children's fruit, juice, and vegetable consumption.

Children's intakes of fruit, juice, and vegetables (FJV) do not meet the recommended minimum of five daily servings, placing them at increased risk for development of cancer and other diseases. Because children's food preferences and practices are initiated early in life (e.g., 2-5 years of age), early dietary intervention programs may have immediate nutritional benefit, as well as reduce chronic disease risk when learned healthful habits and preferences are carried into adulthood. Families and child-care settings are important social environments within which food-related behaviors among young children are developed. FJV preferences, the primary predictor of FJV consumption in children, are influenced by availability, variety, and repeated exposure. Caregivers (parents and child-care providers) can influence children's eating practices by controlling availability and accessibility of foods, meal structure, food modeling, food socialization practices, and food-related parenting style. Much remains to be learned about how these influences and practices affect the development of FJV preferences and consumption early in life.

Ecological and socioeconomic correlates of fruit, juice, and vegetable consumption among African-American boys.

BACKGROUND: Investigators have reported that the availability of foods in local grocery stores correlated with consumption when using large geopolitical units of analysis, e.g., zip codes. Associations across smaller geopolitical units, e.g., census tracts, have not been tested, nor has this work focused on restaurant availability, child consumption, or specific ethnic groups. METHODS: This study examined whether median family income and fruit, juice, and vegetable (FJV) availability in grocery stores, restaurants, and homes in 11 census tracts correlated with FJV consumption among 11- to 14-year-old African-American Boy Scouts. FJV consumption was measured in 90 scouts using two 24-h food recalls. Instruments were developed to measure the availability of FJV at area grocery stores, restaurants, and homes where troop members resided. RESULTS: Median household income (from 1990 census) was significantly correlated with restaurant fruit availability. Significant correlations were found between restaurant juice and vegetable availability and Boy Scout reported consumption of juice and vegetables. CONCLUSION: Census tract may be a useful unit when studying restaurant, but not grocery store, FJV availability. Within a census tract, restaurant FJV availability may be a significant target for community intervention and process evaluation.

Dose-related effects of controlled release dihydrocodeine on oro-cecal transit and pupillary light reflex. A study in human volunteers.

It is well accepted that long-term administration of opioids results in a dose-related constipation. No data so far have demonstrated conclusively whether such constipation is also seen after intake of a controlled release formulation. It was therefore of interest to evaluate whether increasing doses of a controlled release formulation of dihydrocodeine (DHC, CAS 125-28-0) after oral administration also induces a dose-related increase in constipation. Additionally, it was of interest to study whether such a peripheral opioid-related side effect is also seen in another, central receptor-mediated effect, the constriction of the pupil, at clinically relevant doses. Twelve volunteers were given controlled release DHC (60 and 120 mg, respectively) or placebo orally within a randomized, double-blind cross-over study. In order to determine the degree of constipation, oro-cecal transit time was measured using the H2-exhalation test. Additionally, in order to evaluate a centrally mediated effect, the response of the pupil to light was quantified using the pupillary light reflex technique. Both, peripherally and centrally mediated effects were compared to placebo. DHC at both dosages induced a significant (p < 0.01) prolongation of oro-cecal transit time when compared to placebo. However, prolongation of oro-cecal transit was not significantly longer when comparing the lower (60 mg) with the higher dose (120 mg). DHC also induced a significant (p < 0.005) depression of the pupillary light reflex from 53.9 mm (control) to 8.3 and 7.4 mm, respectively. Similar to intestinal transit, the pupillary light reflex was not significantly different among the two doses of DHC. Also, both dosages induced a similar amount of side effects. Tiredness and dry mouth were reported in 80% after both doses while vertigo was reported in 5% and 1% complained of headache. None of the volunteers reported nausea or emesis. It is concluded that opioid receptor sites, which are located in the plexus myentericus of the intestinal wall, are responsible for the delay in propulsion. Because of the controlled release of a fixed amount of DHC over time there is constant binding of the ligand followed by a constant conformational change of peripheral and central receptor sites. Thus constant release induces no dose-related increase in oro-cecal transit and inhibition of the pupillary light reflex.