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Individuals born small have an increased risk for developing type 2 diabetes. Altered food preferences in these subjects seem to play a role; however, limited evidence is available on the association between being born small-for-gestational-age (SGA) at term and food intake in adolescence. Alterations in leptin, ghrelin and dopamine levels are suggested mechanisms linking SGA with later food intake. From a large prospective Danish National Birth Cohort, we compared dietary intake of adolescents being born SGA with normal-for-gestational-age (NGA) adolescents. Intake of foods and nutrients was assessed by a validated food frequency questionnaire in a subsample of 15,607 14-year-old individuals born at term. SGA was defined by birth weight (BW) <10th percentile (n = 1470) and NGA as BW between 10 and 90th percentile (n = 14,137) according to sex and gestational age-specific BW standard curves. Girls born SGA had a 7% (95% CI: 3–12%, P = 0.002) higher intake of added sugar and a 2–8% lower intake of dietary fibre, vegetables, polyunsaturated fatty acids, and total n−6, compared with NGA girls (P < 0.05). Adjusting for parental socio-occupational status, maternal smoking and diet in pregnancy did not substantially change the differences in dietary intake, except from dietary fibre, which were no longer statistically significant. No significant differences in dietary intake between SGA and NGA boys were found. In summary, girls born SGA had an unfavourable dietary intake compared with NGA girls. These differences persisted after controlling for potential confounders, thus supporting a fetal programming effect on dietary intake in girls born SGA at term. However, residual confounding by other factors operating early in childhood cannot be excluded.
Childbirth is a potent trigger for the onset of psychiatric illness in women including postpartum depression (PPD) and postpartum psychosis (PP). Medical complications occurring during pregnancy and/or childbirth have been linked to postpartum psychiatric illness and sociodemographic factors. We evaluated if pregnancy and obstetrical predictors have similar effects on different types of postpartum psychiatric disorders.
A population-based cohort study using Danish registers was conducted in 392 458 primiparous women with a singleton delivery between 1995 and 2012 and no previous psychiatric history. The main outcome was first-onset postpartum psychiatric episodes. Incidence rate ratios (IRRs) were calculated for any psychiatric contact in four quarters for the first year postpartum.
PPD and postpartum acute stress reactions were associated with pregnancy and obstetrical complications. For PPD, hyperemesis gravidarum [IRR 2.69, 95% confidence interval (CI) 1.93–3.73], gestational hypertension (IRR 1.84, 95% CI 1.33–2.55), pre-eclampsia (IRR 1.45, 95% CI 1.14–1.84) and Cesarean section (C-section) (IRR 1.32, 95% CI 1.13–1.53) were associated with increased risk. For postpartum acute stress, hyperemesis gravidarum (IRR 1.93, 95% CI 1.38–2.71), preterm birth (IRR 1.51, 95% CI 1.30–1.75), gestational diabetes (IRR 1.42, 95% CI 1.03–1.97) and C-section (IRR 1.36, 95% CI 1.20–1.55) were associated with increased risk. In contrast, risk of PP was not associated with pregnancy or obstetrical complications.
Pregnancy and obstetrical complications can increase the risk for PPD and acute stress reactions but not PP. Identification of postpartum women requiring secondary care is needed to develop targeted approaches for screening and treatment. Future work should focus on understanding the contributions of psychological stressors and underlying biology on the development of postpartum psychiatric illness.
Dietary long-chain n-3 PUFA (n-3 LCPUFA) in infancy may have long-term effects on lifestyle disease risk. The present follow-up study investigated whether maternal fish oil (FO) supplementation during lactation affected growth and blood pressure in adolescents and whether the effects differed between boys and girls. Mother–infant pairs (n 103) completed a randomised controlled trial with FO (1·5 g/d n-3 LCPUFA) or olive oil (OO) supplements during the first 4 months of lactation; forty-seven mother–infant pairs with high fish intake were followed-up for 4 months as the reference group. We also followed-up 100 children with assessment of growth, blood pressure, diet by FFQ and physical activity by 7-d accelerometry at 13·5 (sd 0·4) years of age. Dried whole-blood fatty acid composition was analysed in a subgroup (n 49). At 13 years of age, whole-blood n-3 LCPUFA, diet, physical activity and body composition did not differ between the three groups. The children from the FO group were 3·4 (95 % CI 0·2, 6·6) cm shorter (P=0·035) than those from the OO group, and tended to have less advanced puberty (P=0·068), which explained the difference in height. There was a sex-specific effect on diastolic blood pressure (Psex×group=0·020), which was driven by a 3·9 (95 % CI 0·2, 7·5) mmHg higher diastolic blood pressure in the FO compared with the OO group among boys only (P=0·041). Our results indicate that early n-3 LCPUFA intake may reduce height in early adolescence due to a delay in pubertal maturation and increase blood pressure specifically in boys, thereby tending to counteract existing sex differences.
Universal screening for postpartum depression is recommended in many countries. Knowledge of whether the disclosure of depressive symptoms in the postpartum period differs across cultures could improve detection and provide new insights into the pathogenesis. Moreover, it is a necessary step to evaluate the universal use of screening instruments in research and clinical practice. In the current study we sought to assess whether the Edinburgh Postnatal Depression Scale (EPDS), the most widely used screening tool for postpartum depression, measures the same underlying construct across cultural groups in a large international dataset.
Ordinal regression and measurement invariance were used to explore the association between culture, operationalized as education, ethnicity/race and continent, and endorsement of depressive symptoms using the EPDS on 8209 new mothers from Europe and the USA.
Education, but not ethnicity/race, influenced the reporting of postpartum depression [difference between robust comparative fit indexes (∆*CFI) < 0.01]. The structure of EPDS responses significantly differed between Europe and the USA (∆*CFI > 0.01), but not between European countries (∆*CFI < 0.01).
Investigators and clinicians should be aware of the potential differences in expression of phenotype of postpartum depression that women of different educational backgrounds may manifest. The increasing cultural heterogeneity of societies together with the tendency towards globalization requires a culturally sensitive approach to patients, research and policies, that takes into account, beyond rhetoric, the context of a person's experiences and the context in which the research is conducted.
We described levels of habitual physical activity and physical capacity in HIV patients initiating antiretroviral treatment in Ethiopia and assessed the role of HIV and nutritional indicators on these outcomes. Physical activity energy expenditure (PAEE) and activity levels were measured with combined heart rate and movement sensors. Physical capacity was assessed by grip strength, sleeping heart rate and heart rate economy. Grip strength data was also available from a sex- and age-matched HIV-negative reference group. Median PAEE was 27·9 (interquartile range 17·4–39·8) kJ/kg per day and mean±s.d. grip strength was 23·6 ± 6·7 kg. Advanced HIV disease predicted reduced levels of both physical activity and capacity; e.g. each unit viral load [log(1+copies/ml)] was associated with –15% PAEE (P < 0·001) and –1·0 kg grip strength (P < 0·001). Grip strength was 4·2 kg lower in patients compared to HIV-negative individuals (P < 0·001). Low body mass index (BMI) predicted poor physical activity and capacity independently of HIV status, e.g. BMI <16 was associated with −42% PAEE (P < 0·001) and −6·8 kg grip strength (P < 0·001) compared to BMI ⩾18·5. The study shows that advanced HIV and malnutrition are associated with considerably lower levels of physical activity and capacity in patients at initiation of antiretroviral treatment.
To identify risk factors for Clostridium difficile infection (CDI) in Danish patients consulting general practice with gastrointestinal symptoms, a prospective matched case-control study was performed; cases (N = 259) had positive cultures for toxigenic C. difficile and controls (N = 455) negative cultures. Data were analysed by conditional logistic regression. In patients aged ⩾2 years (138 cases), hospitalization [odds ratio (OR) 8·4, 95% confidence interval (CI) 3·1–23], consumption of beef (OR 5·5, 95% CI 2·0–15), phenoxymethylpenicillin (OR 15, 95% CI 2·7–82), dicloxacillin (OR 27, 95% CI 3·6–211), and extended spectrum penicillins (OR 9·2, 95% CI 1·9–45) were associated with CDI. In patients aged <2 years none of these were associated with CDI, but in a subgroup analysis contact with animals was associated with CDI (OR 8·1, 95% CI 1·0–64). This study emphasizes narrow-spectrum penicillins, and suggests beef consumption, as risk factors for CDI in adults, and indicates a different epidemiology of CDI in infants.
PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed 2.5-m optical/infrared telescope to be located at Dome C on the Antarctic plateau. The atmospheric conditions at Dome C deliver a high sensitivity, high photometric precision, wide-field, high spatial resolution, and high-cadence imaging capability to the PILOT telescope. These capabilities enable a unique scientific potential for PILOT, which is addressed in this series of papers. The current paper presents a series of projects dealing with the nearby Universe that have been identified as key science drivers for the PILOT facility. Several projects are proposed that examine stellar populations in nearby galaxies and stellar clusters in order to gain insight into the formation and evolution processes of galaxies and stars. A series of projects will investigate the molecular phase of the Galaxy and explore the ecology of star formation, and investigate the formation processes of stellar and planetary systems. Three projects in the field of exoplanet science are proposed: a search for free-floating low-mass planets and dwarfs, a program of follow-up observations of gravitational microlensing events, and a study of infrared light-curves for previously discovered exoplanets. Three projects are also proposed in the field of planetary and space science: optical and near-infrared studies aimed at characterising planetary atmospheres, a study of coronal mass ejections from the Sun, and a monitoring program searching for small-scale Low Earth Orbit satellite debris items.
PILOT (the Pathfinder for an International Large Optical Telescope) is a proposed 2.5-m optical/infrared telescope to be located at Dome C on the Antarctic plateau. Conditions at Dome C are known to be exceptional for astronomy. The seeing (above ∼30 m height), coherence time, and isoplanatic angle are all twice as good as at typical mid-latitude sites, while the water-vapour column, and the atmosphere and telescope thermal emission are all an order of magnitude better. These conditions enable a unique scientific capability for PILOT, which is addressed in this series of papers. The current paper presents an overview of the optical and instrumentation suite for PILOT and its expected performance, a summary of the key science goals and observational approach for the facility, a discussion of the synergies between the science goals for PILOT and other telescopes, and a discussion of the future of Antarctic astronomy. Paper II and Paper III present details of the science projects divided, respectively, between the distant Universe (i.e. studies of first light, and the assembly and evolution of structure) and the nearby Universe (i.e. studies of Local Group galaxies, the Milky Way, and the Solar System).
A total of 111 clinical and environmental O1, O139 and non-O1/O139 Vibrio cholerae strains isolated between 1978 and 2008 from different geographical areas were typed using a combination of methods: antibiotic susceptibility, biochemical test, serogroup, serotype, biotype, sequences containing variable numbers of tandem repeats (VNTRs) and virulence genes ctxA and tcpA amplification. As a result of the performed typing work, the strains were organized into four clusters: cluster A1 included clinical O1 Ogawa and O139 serogroup strains (ctxA+ and tcpA+); cluster A2 included clinical non-O1/O139 strains (ctxA− and tcpA−), as well as environmental O1 Inaba and non-O1/O139 strains (ctxA− and tcpA−/tcpA+); cluster B1 contained two clinical O1 strains and environmental non-O1/O139 strains (ctxA− and tcpA+/tcpA−); cluster B2 contained clinical O1 Inaba and Ogawa strains (ctxA+ and tcpA+). The results of this work illustrate the advantage of combining several typing methods to discriminate between clinical and environmental V. cholerae strains.
A contender for future generations of CMOS technology is the strained silicon (S-Si) MOSFET. The mobility enhancement in S-Si can be exploited to maintain the performance enhancements demanded by Moore's law with reduced critical dimensions. S-Si is obtained by growth of a thin Si layer over a thick virtual substrate (VS) of relaxed silicon-germanium (SiGe). The mobility of a surface channel MOSFET is dependent on the quality of the silicon-oxide (Si/SiO2) interface. Ge may out diffuse from the virtual substrate to the oxide interface causing an increase in trapping density. As the Ge content in the virtual substrate increases surface roughness also increases. These phenomena both lead to a reduction in mobility.
The study of a matrix of devices having variable Ge composition and S-Si thickness is crucial in deconvolving the contributions of Ge diffusion and wafer cross-hatching roughness on electrical parameters. Increasing VS Ge composition increases the Ge concentration at the SSi/SiO2 interface and cross-hatching amplitude whereas reducing S-Si channel thickness only increases Ge concentration at the S-Si/SiO2 interface and does not increase cross-hatch amplitude. Interface state density, drive current, gate leakage current, transconductance and carrier mobility data are presented for this two-dimensional space of VS composition and S-Si thickness. The relative importance of Ge diffusion and cross-hatching roughness can be seen in this data. The results of this study indicate a lower limit of 7 nm for the S-Si thickness and an upper limit of approximately 20 % Ge in the virtual substrate for the current processing technology. Understanding the performance-limiting mechanisms in S-Si is crucial in the optimisation of VS Ge composition and S-Si thickness for current and future generations of S-Si CMOS.
Four Cu-Zr alloys, Cu56Zr44, Cu50Zr50, Cu47Zr53, and Cu33Zr67, were surface melted with electron and pulsed laser beams to compare their kinetics of nucleation, growth and glass formation. It was observed that the ease of glass formation increased in the order: Cu33Zr67, Cu47Zr53, Cu56Zr44, and Cu50Zr50. The nucleation and regrowth produced different metastable phases. At the equiatomic composition, the preferred phase is a CsCl-type (B2) BCC structure. As the composition deviates from this, the preferred phase is either orthorhombic or tetragonal with a much larger unit cell not previously reported in the literature. The maximum growth velocity of these metastable phases was found to be about 0.025 m/s. The slow kinetics are responsible for the ease of glass formation in these systems.
Si nanocrystallites have been prepared by ultrasonicating thin sections of porous silicon. The materials produced from 20 and 49 wt % HF are characterized and compared. Samples were characterized by optical absorption and photoluminescence spectroscopy, and HRTEM.
Two complementary techniques are used to study the electrical transport properties related to the use of diamonds as materials for ionizing radiation detectors. Transient photoconductivity using soft x-rays is used to probe the first few microns of the material, while ionizing particle-excited conductivity is used to probe the entire bulk of the material (1 millimeter). Both techniques measure the mean drift distance of free carriers, or the collection distance d. In addition, transient photoconductivity is able to extract the lifetimes and mobilities of the excited carriers. The collection distance measured by the two methods are in agreement, suggesting the material is homogeneous. At an applied field of 10 kV/cm, d is 25 to 30 microns, and, up to a field of 25 kV/cm, d has not saturated. The lifetime varies between 100 and 600 ps, and the mobility varies between 1000 and 4000 cm2/V-s, the range due to natural variations from sample to sample. The primary defects limiting the lifetime are believed to be nitrogen impurities and dislocations.
Muon diffusion can be studied in metals without nuclear moments by the addition of paramagnetic impurities. We describe the theory and report measurements of muon depolarization in gold and silver doped with gadolinium and erbium. As well as diffusion rates, strength of the magnetic interaction and spin lattice relaxation rate of the paramagnetic ion are inferred from the data.
We have begun a systematic investigation the electrical transport properties of the AlPdMn quasicrystalline system. Resistivity and thermopower measurements have been performed over a temperature range between 5K and 320K. In the pure, single phase Al70Pd20Mn10 we have observed thermopowers as high as +80 μV/K around room temperature with resistivities of 1.5 mΩ-cm. Thermal conductivity measurements have been performed yielding values less than 2 W/m-K for all the samples investigated to date. We will discuss how the thermopower and resistivity vary as a result of differing sample composition as well as different processing and annealing conditions. Several different preparation techniques have been employed to further understand how various factors affect the thermal and electrical properties of this quasicrystalline system and how these may be adjusted to optimize these materials for possible thermoelectric applications.
We have identified quasicrystals and quasicrystalline approximants as potential candidates for small scale thermoelectric power generation and refrigeration applications. A number of quasicrystalline systems have been investigated, however, the focus in this paper will be on the ALPdMn (typically Al70Pd20Mn10) system. Currently, we are systematically investigating the electrical and thermal transport properties of the AlPdMn quasicrystalline system in relation to differing sample composition, systematic addition of impurities, and different annealing conditions. Several different preparation techniques have been employed in order to determine optimal techniques for maximizing the thermal and electrical properties of this quasicrystalline system for possible thermoelectric applications. Resistivity and thermopower have been performed over a temperature range between 5K and 320K. Thermal conductivity measurements have been performed over a temperature range between 20K and 300K. In the pure, single phase nominally Al70Pd20Mn10 we have observed thermopower values as high as +85 μV/K around room temperature with resistivity values of 1.5 mΩ-cm. Thermal conductivity measurements yield values less than 3 W/m-K. We will discuss how these properties are affected by the parameters we have varied and the trends we have observed so far. We will discuss the future investigations of the electrical and thermal transport properties of quasicrystals in relation to potential thermoelectric applications.
Partially due to their lack of periodic structure, quasicrystals have inherently low thermal conductivity on the order of 1 - 3 W/m-K. AlPdMn quasicrystals exhibit favorable room temperature values of electrical conductivity, 500–800 (Ω-cm)-1, and thermopower, 80 μV/K, with respect to thermoelectric applications. In an effort to further increase the thermopower and hopefully minimize the thermal conductivity via phonon scattering, quartenary Al71Pd21Mn8-XReX quasicrystals were grown. X-ray data confirms that the addition of a fourth element does not alter the quasiperiodicity of the sample. Al71Pd21Mn8-XReX quasicrystals of varying Re concentration were synthesized where x had values of 0, 0.08, 0.25, 0.4, 0.8, 2, 5, 6, and 8. Both thermal and electrical transport property measurements have been performed and are reported.
Although pneumonia is a leading cause of death from infectious disease worldwide, comprehensive information about its causes and incidence in low- and middle-income countries is lacking. Active surveillance of hospitalized patients with pneumonia is ongoing in Thailand. Consenting patients are tested for seven bacterial and 14 viral respiratory pathogens by PCR and viral culture on nasopharyngeal swab specimens, serology on acute/convalescent sera, sputum smears and antigen detection tests on urine. Between September 2003 and December 2005, there were 1730 episodes of radiographically confirmed pneumonia (34·6% in children aged <5 years); 66 patients (3·8%) died. A recognized pathogen was identified in 42·5% of episodes. Respiratory syncytial virus (RSV) infection was associated with 16·7% of all pneumonias, 41·2% in children. The viral pathogen with the highest incidence in children aged <5 years was RSV (417·1/100 000 per year) and in persons aged ⩾50 years, influenza virus A (38·8/100 000 per year). These data can help guide health policy towards effective prevention strategies.
To compare incidence of hospital-onset Clostridium difficile infection (CDI) measured by the use of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) discharge diagnosis codes with rates measured by the use of electronically available C. difficile toxin assay results.
Cases of hospital-onset CDI were identified at 5 US hospitals during the period from July 2000 through June 2006 with the use of 2 surveillance definitions: positive toxin assay results (gold standard) and secondary ICD-9-CM discharge diagnosis codes for CDI. The x2 test was used to compare incidence, linear regression models were used to analyze trends, and the test of equality was used to compare slopes.
Of 8,670 cases of hospital-onset CDI, 38% were identified by the use of both toxin assay results and the ICD-9-CM code, 16% by the use of toxin assay results alone, and 45% by the use of the ICD-9-CM code alone. Nearly half (47%) of cases of CDI identified by the use of a secondary diagnosis code alone were community-onset CDI according to the results of the toxin assay. The rate of hospital-onset CDI found by use of ICD-9-CM codes was significantly higher than the rate found by use of toxin assay results overall (P<.001), as well as individually at 3 of the 5 hospitals (P<.001 for all). The agreement between toxin assay results and the presence of a secondary ICD-9-CM diagnosis code for CDI was moderate, with an overall k value of 0.509 and hospital-specific k values of 0.489–0.570. Overall, the annual increase in CDI incidence was significantly greater for rates determined by the use of ICD-9-CM codes than for rates determined by the use of toxin assay results (P = .006).
Although the ICD-9-CM code for CDI seems to be adequate for measuring the overall CDI burden, use of the ICD-9-CM discharge diagnosis code for CDI, without present-on-admission code assignment, is not an acceptable surrogate for surveillance for hospital-onset CDI.