Tomographic imaging and scanning thermal microscopy: thermal impedance tomography

The application of tomographic imaging techniques developed for medical applications to the data provided by the scanning thermal microscope will give access to true three-dimensional information on the thermal properties of materials on a mm length scale. In principle, the technique involves calculating and inverting a sensitivity matrix for a uniform isotropic material, collecting ordered data at several modulation frequencies, and multiplying the inverse of the matrix with the data vector. In practice, inversion of the matrix in impractical, and a novel iterative technique is used. Examples from both simulated and real data are given

Sub-wavelength surface IR imaging of soft-condensed matter

Outlined here is a technique for sub-wavelength infrared surface imaging performed using a phase matched optical parametric oscillator laser and an atomic force microscope as the detection mechanism. The technique uses a novel surface excitation illumination approach to perform simultaneously chemical mapping and AFM topography imaging with an image resolution of 200 nm. This method was demonstrated by imaging polystyrene micro-structures

A Comparative Study on Spinel Iron-cobalt Oxide Prepared by Co-precipitation and Hydrothermal Routes

Spinel iron-cobalt oxide was synthetized by coprecipitation and hydrothermal process. The nanostruc-tures of the prepared samples were characterized as functions of the calcination temperature and the hy-drothermal synthesis time, using X-ray powder diffractometry (XRD) and nitrogen adsorption–desorption technique ( BET, BJH ). Using chloride salts as start materials and both of sodium hydroxide and ammo-nia as precipitating agents; The results show that the CoFe2O4 obtained has a mesoporous structure with a pore distribution strongly depending on the experimental conditions. The crystallite size and lattice pa-rameter showed a same variation as function of ( i ) the calcination temperature in the coprecipitation method, ( ii ) the synthesis time in the hydrothermal process. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3509

Tailored preconceptional dietary and lifestyle counselling in a tertiary outpatient clinic in the Netherlands

Background Adverse reproductive performance has been linked to unhealthy dietary intake and lifestyles. Our objectives were to investigate the prevalence of unhealthy dietary intake and lifestyles before conception and to evaluate whether tailored preconception counselling modifies these behaviours. Methods Between October 2007 and April 2009, 419 couples received tailored preconception dietary and lifestyle counselling at the outpatient clinic of Obstetrics and Gynaecology of the Erasmus University Medical Center Rotterdam, the Netherlands. A subgroup (n = 110 couples) was counselled twice with a fixed time interval of 3 months. Self-administered questionnaires were used for tailored dietary and lifestyle counselling. A cumulative score based on six Dutch dietary guidelines was displayed in the personal Preconception Dietary Risk score (PDR score). In a similar manner, the Rotterdam Reproduction Risk score (R3 score) was calculated from lifestyle factors (women: 13 items, men: 10 items). Univariate and paired tests were used. Results Most couples (93.8) were subfertile. At the second counselling, the percentage consuming the recommended intake of fruit had increased from 65 to 80 in women and from 49 to 68 in men and the percentage of women getting the recommended intake of fish increased from 39 to 52. As a consequence, the median PDR score was decreased [women: 2.6 (95 CI 2.4-2.9) to 2.4 (95 CI 2.1-2.6), men: 2.5 (95 CI 2.3-2.7) to 2.2 (95 CI 1.9-2.4), both P < 0.05]. The median R3 scores were also lower [women: 4.7 (95 CI 4.3-5.0) to 3.1 (95 CI 2.8-3.4), men: 3.0 (95 CI 2.8-3.3) to 2.0 (95 CI 1.7-2.3), both P < 0.01] due to less alcohol use (-14.6), more physical exercise and folic acid use in women, and less alcohol use in men (-19.4) (all P < 0.01). The R3 scores in women and men were decreased in all ethnicity, educational level, neighbourhood and BMI categories. However, low educated women appeared to show a larger reduction than better educated women and men with a normal BMI to show a larger decrease than overweight men. The reduction in the PDR score of women was similar in both ethnic groups. More than 85 women and men found the counselling useful and around 70 would recommend it to others. Conclusions Tailored preconception counselling about unhealthy dietary and lifestyle behaviours of subfertile couples in an outpatient tertiary clinic is feasible and seems to decrease the prevalence of harmful behaviours in the short term. These Results with subfertile couples are promising and illustrate their opportunities to contribute to reproductive performance and pregnancy outcome

Thermal Conductivity of Ordered Mesoporous Nanocrystalline Silicon Thin Films Made from Magnesium Reduction of Polymer-Templated Silica

This paper reports the cross-plane thermal conductivity of ordered mesoporous nanocrystalline silicon thin films between 25 and 315 K. The films were produced by evaporation induced self-assembly of mesoporous silica followed by magnesium reduction. The periodic ordering of pores in mesoporous silicon was characterized by X-ray diffraction and direct SEM imaging. The average crystallite size, porosity, and film thickness were about 13 nm, 25-35%, and 140-340 nm, respectively. The pores were arranged in a face-centered cubic lattice. The cross-plane thermal conductivity of the mesoporous silicon thin films was measured using the 3ω method. It was between 3 and 5 orders of magnitude smaller than that of bulk single crystal silicon in the temperature range considered. The effects of temperature, film thickness, and copolymer template on the thermal conductivity were investigated. A model based on kinetic theory was used to accurately predict the measured thermal conductivity for all temperatures. On the one hand, both the measured thermal conductivity and the model predictions showed a temperature dependence of k proportional to T2 at low temperatures, typical of amorphous and strongly disordered materials. On the other hand, at high temperatures the thermal conductivity of mesoporous silicon films reached a maximum, indicating a crystalline-like behavior. These results will be useful in designing mesoporous silicon with desired thermal conductivity by tuning its morphology for various applications

Parental diet, pregnancy outcomes and offspring health:metabolic determinants in developing oocytes and embryos

The periconceptional period, embracing the terminal stages of oocyte growth and post-fertilisation development up to implantation, is sensitive to parental nutrition. Deficiencies or excesses in a range of macro- and micronutrients during this period can lead to impairments in fertility, fetal development and long-term offspring health. Obesity and genotype-related differences in regional adiposity are associated with impaired liver function and insulin resistance, and contribute to fatty acid-mediated impairments in sperm viability and oocyte and embryo quality, all of which are associated with endoplasmic reticulum stress and compromised fertility. Disturbances to maternal protein metabolism can elevate ammonium concentrations in reproductive tissues and disturb embryo and fetal development. Associated with this are disturbances to one-carbon metabolism, which can lead to epigenetic modifications to DNA and associated proteins in offspring that are both insulin resistant and hypertensive. Many enzymes involved in epigenetic gene regulation use metabolic cosubstrates (e.g. acetyl CoA and S-adenosyl methionine) to modify DNA and associated proteins, and so act as 'metabolic sensors' providing a link between parental nutritional status and gene regulation. Separate to their genomic contribution, spermatozoa can also influence embryo development via direct interactions with the egg and by seminal plasma components that act on oviductal and uterine tissues

Midinfrared photoluminescence of InAsSb quantum dots grown by liquid phase epitaxy. .

Photoluminescence in the 2–5 µm spectral region is reported from InAs1–xSbx quantum dots grown from the liquid phase at 580 °C on an InAs (100) substrate. Atomic force microscopy shows that coalesced quantum dots and then isolated quantum dots are formed with increasing Sb composition (x = 0.2–0.3) and strain. The 4 K photoluminescence of the isolated and coalesced quantum dots was observed to peak in the midinfrared at 289 and 316 meV, (4.29 and 3.92 µm), respectively. These peaks are due to type II transitions and begin to quench at temperatures above 100 K as holes become thermally activated out of the quantum dot confinement potential. ©2000 American Institute of Physics

InAsSbP quantum dots grown by liquid phase epitaxy

We report the growth of the first InAs-based quantum dots from the liquid phase using a novel rapid slider liquid phase epitaxial growth technique. Photoluminescence was observed at 4 K from these InAsSbP quantum dots encapsulated in GaAs and grown on a highly mismatched GaAs substrate