Structural study of degraded ZnMgSSe blue light emitters

Using electroluminescence (EL) topography and transmission electron microscopy (TEM), we investigated the nonluminescent regions which form while current is being injected into ZnMgSSe/ZnSSe/ZnCdSe-based blue light emitters. Small dark spots were observed just after turn-on and spread out forming rough nonluminescent triangles in the <100> directions in the EL image of the active region. TEM studies showed that the small dark spots are pre-existing stacking faults originating at the substrate/epitaxial layer interface. The nonluminescent triangles were found to be a dense region of dislocation dipoles and dislocation loops. Each dipole was aligned along two <110> directions in the {111} planes. The Burgers vectors were of the type a/2<011> inclined at 45° to the (001) junction plane.     

Reconstruction of a signal using the spectrum-reversal technique

Our procedure of real-zero conversion uses a spectrum-reversal technique to convert the information of a bandlimited signal to real zeros. We conducted a simple reconstruction experiment and showed that our proposed method is essentially equivalent to the conventional technique of sine-wave crossings     

Swelling of hydrophilic polymers. III

The total volume change included gel and surrounded water with the swelling of five types of speherical cross-linked dextran (Sephadex) that are either nonionic (G) or possess one of four different ionic groups in the same molecular skeleton: CM: sodium carboxymethyl, SP: sodium sulphopropyl, DEAE: diethylaminoethyl chloride, and QAE: diethyl-(2-hydroxypropyl) aminoethyl chloride. All have been studied by dilatometry. The total volume decreased with the swelling of all Sephadexes. The maximum changes of total volume with the swelling in water were all negatives of CM, G, SP, (DEAE, QAE), which decrease in that order. These values did not depend on the concentration of sodium chloride and were closely related to the maximum heats of swelling. Total volume changes occurred by the dissociation of the ionic group of dextran derivatives that subtracted the total volume change due to hydration of Sephadex skeleton from the total volume change: ?21.6 ± 3.1 μL mmol^?1 for CM, ?2.8 ± 8.0 μL mmol^?1 for SP, +13.2 ± 4.4 μL mmol^?1 for DEAE, and +15.4 ± 4.6 μL mmol^?1 for QAE. These values are assumed to be reflected in the quantities of ions-water interaction of Sephadexes. © 1994 John Wiley & Sons, Inc.     

Peptide separation in normal phase liquid chromatography

A new method is established for separating peptides in normal phase liquid chromatography using TSK gel Amide-80, carbamoyl groups bonded to a silica gel matrix, and an acetonitrile-water solution containing 0.1% trifluoroacetic acid. Peptide retention time increased with acetonitrile concentration in the initial eluent. Hydrophilic peptides with no retention in a reversed phase column were retained and separated in the present method. Separation selectivities in the present and reversed phase methods differed significantly. Two-dimensional separation of protein digest using reversed and normal phases was conducted, taking advantage of the differences in selectivities. All peptides obtained from the digest could be separated completely. The present method is useful for separating peptide mixtures in conjunction with reversed phase liquid chromatography. Peptide recovery from the Amide-80 column exceeded 80%, as with the reversed phase column, and repeatability and reproducibility were satisfactory.     

Differential regulation by hematopoietic growth factors of apoptosis and mitosis in acute myeloblastic leukemia cells

We evaluated the effects of various hematopoietic growth factors (HGFs) on the prevention of apoptosis in blasts from 19 patients with acute myeloblastic leukemia (AML) by assessing DNA ladder formation. After incubation without HGF, apoptosis was noted in all but two patients. HGFs prevented, did not affect, or enhanced apoptosis in 39 (60%), 14 (22%), or 12 (18%) of 65 suspension cultures, respectively. HGFs that prevented apoptosis also stimulated and/or synergized blast colony formation in 35 of 39 corresponding methylcellulose cultures. HGFs that alone stimulated colony formation also prevented apoptosis in all but two of 28 corresponding suspension cultures. In contrast, HGFs that did not prevent apoptosis also failed to stimulate growth in 17 of 26 corresponding methylcellulose cultures. HGFs that enhanced apoptosis alone never stimulated colony formation. After incubation, we noted enhanced c-fos and cjun genes as well as induction of p21 protein. An appropriate dose of HGF elevated c-fos, reduced c-jun and p21, induced G1/S transition, and inhibited apoptosis. In two patients, apoptosis was not induced after incubation. Cells not treated with HGF expressed no c-fos, c-jun, or c-myc, and remained in G0/G1. Taken together, our results support the conclusion that not only c-fos, cjun, and c-myc, but also p53 and p21 are required for blast apoptosis. HGF differentially prevents apoptosis and induces mitosis, and both events seem to be integral to the self-renewal of AML clonogenic cells.     

Late complications in traumatic coronary artery fistula: report of a case requiring surgical repair after 8 years

A full-length cDNA clone for a progesterone membrane binding protein from porcine vascular smooth muscle cells was isolated and the complete nucleotide sequence determined. The cDNA encodes a protein of 194 amino acids with a transmembrane segment. This protein is likely to represent the first steroid membrane receptor or a part of it for which sequence information is available.     

Identification of K1/K10 and K5/K14 keratin pairs in human melanoma cell lines

Keratin expression in cultured malignant melanoma cells has been studied only rarely. Moreover, no studies have reported of universality of keratin expression in human malignant melanoma cells. In this study, therefore, we analyzed keratin expression in eight cell lines. Using a low-salt aqueous solution without high salt and Triton X-100, as a washing buffer for keratin extraction, followed by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and immunological analysis, we demonstrated keratin expression in all eight human malignant melanoma cell lines. The keratin polypeptide expressions common to all melanoma cells were K1, K5, K10 and K14. In addition, K8, K13, K17 and K18, respectively, were detected in individual cells. A measure of keratin expression universality in malignant melanoma cells may have implications regarding their invasive and metastatic behaviors, co-expressed with vimentin.     

Marmaray project: Tunnels and stations in BC contract

Istanbul is one of the most famous historical cities in the world. However, the project alignment selected as the best of a range of alignments cannot avoid passing beneath the historical and cultural heritages of Istanbul as well as under ancient and densely inhabited areas of the city. This paper will explain some of the challenges related to the bored tunnels.

Historical buildings are vulnerable. Yet many existing residential and office buildings are old and constructed on minimal foundations. As a consequence, it is vital that any drawdown of groundwater and any ground settlements have to be minimized.

In addition, the connection between the immersed and bored tunnels will be made directly and totally underground, without the usual intermediate shafts and beneath the deep waters of the Bosphorus Strait. This operation needs the utmost control of the tunnel excavation face to ensure its stability and to minimize water ingress. Based on such considerations, tunnel excavation by tunnel boring machine (TBM) using a slurry shield and having the ability to operate under high pore pressures was recommended as the method of excavation for the main running tunnels.

The paper will explain how the design team from Avrasyaconsult – the Employer’s Representative – arrived at the final minimum, specific and functional requirements of the bored tunneling works which are to be carried out using the ‘FIDIC EPC/Turnkey Project’ conditions.