Terahertz Atmospheric Windows for High Angular Resolution Terahertz Astronomy from Dome A

Atmospheric transmission from Dome A, Antarctica, presents new possibilities in the field of terahertz astronomy, where space telescopes have been the only observational tools until now. Using atmospheric transmission measurements from Dome A with a Fourier transform spectrometer, transmission spectra and long-term stabilities have been analyzed at 1.461 THz, 3.393 THz, 5.786 THz and 7.1 THz, which show that important atmospheric windows for terahertz astronomy open for a reasonable length of time in the winter season. With large aperture terahertz telescopes and interferometers at Dome A, high angular resolution terahertz observations are foreseen of atomic fine-structure lines from ionized gas and a water ice feature from protoplanetary disks.Comment: 6 pages, 3 figures, to appear in Advances in Polar Scienc

Magnetoelectric Coupling and Electric Control of Magnetization in Ferromagnet-Ferroelectric-Metal Superlattices

Ferromagnet-ferroelectric-metal superlattices are proposed to realize the large room-temperature magnetoelectric effect. Spin dependent electron screening is the fundamental mechanism at the microscopic level. We also predict an electric control of magnetization in this structure. The naturally broken inversion symmetry in our tri-component structure introduces a magnetoelectric coupling energy of $P M^2$. Such a magnetoelectric coupling effect is general in ferromagnet-ferroelectric heterostructures, independent of particular chemical or physical bonding, and will play an important role in the field of multiferroics.Comment: 5 pages including 3 figures and 1 tabl

Comparison of corneal flap thickness using a FS200 femtosecond laser and a moria SBK microkeratome

<b>AIM:</b> To evaluate differences in flap thickness resulting from use of an Alcon Wavelight FS200 femtosecond laser and a MORIA SBK microkeratome when making a 110-μm-thick corneal flap and to identify the potential factors that affect corneal flap thickness.<b>METHODS:</b> A prospective case study was performed on 120 eyes of 60 patients who were divided into two groups for LASIK, each group consisting of 60 eyes (30 patients). The corneal flaps were created using an Alcon Wavelight FS200 femtosecond laser or a MORIA SBK microkeratome. The central corneal flap thickness was calculated by subtraction pachymetry. Age, central corneal thickness (CCT), spherical equivalent refraction, mean keratometry, and corneal diameter were recorded preoperatively for analysis.<b>RESULTS:</b> Cutting of all flaps was easily performed without intraoperative complications. In the Alcon Wavelight FS200 femtosecond lasergroup, the mean right and left corneal flap thicknesses were 114.0±6.6 μm (range:98-126) and 111.4±7.6 μm (range:98-122), respectively. The difference (2.6±9.1 μm) in the corneal flap thickness between the right and left eyes was not significant (<i>t</i>=1.59, <i>P</i>=0.12). Stepwise regression analysis indicated that the resulting corneal flap thickness was unrelated to the patient’s age, preoperative CCT, spherical equivalent refraction, mean keratometry, or corneal diameter. In the MORIA SBK microkeratome group, the mean right and left corneal flap thicknesses were 110.6±7.4 μm (range:97-125 μm) and 108.2±6.1 μm (range:78-123 μm), respectively. The difference in the corneal flap thickness between the right and left eyes (2.4±6.5μm) was not significant (<i>t</i>=2.039, <i>P</i>=0.0506). The corneal flap thickness was positively correlated with the preoperative CCT through stepwise regression analysis (<i>r</i>=0.297,<i> P</i>=0.021). The corneal flap thickness was not related to age, spherical equivalent refraction, mean keratometry, or corneal diameter. The corneal flap thickness was estimated using the following equation:Tflap=67.77+0.076 CCT (<i>F</i>=5.63, <i>P</i>=0.021).<b>CONCLUSION:</b>Both the Alcon Wavelight FS200 femtosecond laser and the MORIA SBK microkeratome produced 110-μm-thick corneal flaps. The central corneal flap thickness was positively correlated with the preoperative CCT in MORIA SBK microkeratome surgery

Effect of β-nerve growth factor on differentiation of endothelial progenitor cells in rats

Purpose: To investigate the effect of recombinant adenovirus-mediated human β-nerve growth factor (Ad-EGFP-hβ-NGF) on the differentiation of endothelial progenitor cells (EPCs) in rats.Methods: The successfully constructed Ad-EGFP-hβ-NGF and its negative control Ad-EGFP were infected into the isolated and purified rat EPCs to observe their morphological changes. Enzyme-linked immunosorbent assay (ELISA) was conducted to detect the levels of vascular endothelial growth factor (VEGF), von Willebrand factor (vWF) and basic fibroblast growth factor (bFGF) in different rat EPC culture solutions. Western blot was performed to determine the expression of tyrosine kinase receptor A (TrKA) protein in different groups of EPCs.Results: Primary fibrous EPCs were converted into epithelium-like cells. After infection with Ad-EGFPhβ- NGF for 1 week, some EPCs became round and exhibited neural stem cell-like changes. The expression levels of VEGF, vWF and bFGF in the Ad-EGFP-hβ-NGF infection group were significantly higher than those in the control group (p &lt; 0.01). TrKA protein in Ad-EGFP-hβ-NGF infection was also significantly up-regulated compared with that in the negative control and blank control groups (p &lt;0.01).Conclusion: β-NGF up-regulates the expression of TrKA receptor protein and secretion of angiogenic growth factors (i.e., VEGF, vWF and bFGF), thereby promoting the differentiation of rat EPCs, which may contribute to angiopoiesis or vascular repair.Keywords: β-Nerve growth factor, Endothelial progenitor cells, Angiogenic growth factors, Tyrosine kinase receptor A, Cell differentiatio

SYNTHESIS OF CYCLOBUTANE ANALOGUES

2-(3-Acetyl-2,2-dimethylcyclobutyl)acetic acid (pinonic acid) was synthesized using &alpha;-pinene as raw material and potassium permanganate as oxidant. This compound reacted with substituted aniline to produce eight kinds of derivatives with cyclobutane moiety. The yields of the cyclobutane analogues ranged from 24.9 to 78.2 %. KEY WORDS: Cyclobutane analogues, Pinonic acid, Oxidation Bull. Chem. Soc. Ethiop. 2009, 23(1), 135-139