Top-Seeded Melt-Growth of YBa2Cus3Ox Crystals for Neutron Diffraction Studies

We have grown cubic centimeter-size crystals of YBa₂Cu₃O _x suitable for neutron studies, by a top-seeded melt-growth technique. Growth conditions were optimized with an eye toward maximizing phase purity. It was found that the addition of 2% Y₂BaCuO₅ and 0.5% Pt (by mass) were required to prevent melt loss and to obtain the highest crystallinity. A neutron diffraction study on a mosaic of six such crystals found that the final Y₂BaCuO₅ concentration was 5%, while other impurity phases comprised less than 1% by volume. The oxygen content was set to x = 6.5, the crystals were detwinned, and then carefully annealed to give the well-ordered ortho-II phase. The neutron study determined that 70% of the mosaic's volume was in the majority orthorhomic domain. The neutron (006) and (110) rocking curve widths were ～1° per crystal and ～2.2° for the mosaic, and the oxygen chain correlation lengths were >100 Å in the a- and b-directions and ～50 Å in the c-direction.     

Reproducibility of brachial ultrasonography and flow-mediated dilatation (FMD) for assessing endothelial function

Minimally invasive plastic surgery has expanded beyond the original confines of aesthetic applications to encompass all our endeavors in an attempt to restrict the size of surgical scars, limit postoperative discomfort, and hasten recovery of function. This evolution has already delineated methods to raise our workhorse muscle flaps and has negated the risks of laparotomy for various visceral flaps. It is then only a logical progression to use these endoscopic techniques to harvest fascial flaps so as to avoid the notorious donor site morbidity of the fasciocutaneous flap, which has certainly hindered the rapid acceptance of these otherwise valuable flaps. Endoscopic-facilitated elevation of a local adipofascial flap is described for which little or no additional skin incisions need ever be made.     

Brazing as a means of sealing ceramic membranes for use in advanced coal gasification processes

Coal is potentially a very inexpensive source of clean hydrogen fuel for use in fuel cells, turbines, and various process applications. To realize its potential however, efficient low-cost gas separation systems are needed to provide high purity oxygen that will enhance the coal gasification reaction and to extract hydrogen from the resulting gas product stream. Several types of inorganic membranes are being developed for hydrogen or oxygen separation, including porous alumina, transition metal oxide perovskites, and zirconia. Because they form the heart of the working device, numerous advances have been made in the fabrication and performance of these membrane materials. However, less emphasis has been placed on the materials that will be used in the balance of the device; in particular, the seals that bond the functional ceramic to the metallic structural component. In an effort to begin addressing this issue, we have examined ceramic-to-metal brazing as a method of sealing a model set of gas separation component materials: yttria-stabilized zirconia and stainless steel. In comparative high-temperature exposure testing of joints prepared using commercial brazes and a newly conceived braze alloy, the commercial material proved to be unsuitable due to excessive oxidation. On the other hand, the new material not only displayed superior oxidation resistance, but also excellent hermeticity in prototypic membrane testing.     

Notch in contrast sensitivity function of optical origin: diffraction effects of acrylic filters

It was for the first time that of the fifth year of monitoring of Plantago lanceolata L., reproduced within the thirty-kilometer zone of Chernobyl NPP disaster, the authors discovered high incidence of seedlings with various morphological abnormalities. It is suggested that the damages observed are related to the cumulative effect of radiation.     

Dysregulated cyclin D1 expression early in head and neck tumorigenesis: in vivo evidence for an association with subsequent gene amplification

Cyclin D1 proto-oncogene is a key regulator of the mammalian cell-cycle acting at the restriction point in late G1. Amplification of the cyclin D1 locus, located on chromosome 11q13, as well as cyclin D1 protein overexpression have been reported in several human malignancies. The purpose of this study was to evaluate cyclin D1 gene copy status and protein expression during the multistep process of head and neck tumorigenesis, using a combination of fluorescence in situ hybridization and immunohistochemistry techniques. From 29 selected patients presenting with head and neck squamous carcinoma and whose tumor cytospins had been previously screened for presence (16 cases) or absence (13 cases) of amplification at the 11q13 band, we analysed 46 paraffin-embedded tissue specimens that demonstrated, besides the primary tumor, the presence of contiguous adjacent normal tissue and/or premalignant lesions. Of the 16 amplified cases, nine demonstrated a continuous progression from premalignant to invasive carcinoma and seven (77.7%) of these cases showed cyclin D1 gene amplification in premalignant lesions prior to development of invasive carcinoma. Increased cyclin D1 protein expression was observed in all 16 amplified tumors and five of the 13 (38.4%) non-amplified tumors. Interestingly, dysregulated cyclin D1 expression was also found in the premalignant lesions adjacent to all 16 amplified tumors, and it appeared to precede cyclin D1 gene amplification. In contrast no dysregulated expression was detected in the premalignant lesions of the non-amplified tumors. In conclusion, these findings provide strong evidence for early dysregulation of cyclin D1 expression during the tumorigenesis process and suggest that dysregulated increased expression precedes and possibly enables gene amplification.