Elastic Properties of Vanadium Pentoxide Aggregates and Topological Defects

We study the aqueous solution of vanadium pentoxide by using topology methods. The experiments by Zocher, Kaznacheev, and Dogic exhibited that in the sol phases of V₂O₅–H₂O, the tactoid droplets of V₂O₅ can coalesce. In the magnetic field, this effect is associated with a gauge field action, viz. we consider coalescence (“junction,” in the topologically more convenient term) of droplets as annihilation of topological defects, concerning with the tactoid geometry. We have shown, that in the magnetic field, the tactoid junction is mainly caused by non-Abelian monopoles (vortons), whereas the Abelian defects almost do not annihilate. Taking into account this annihilation mechanism, the estimations of time-aging of the V₂O₅–H₂O sols may be specified.     

Stage IA1 cervical adenocarcinoma: definition and treatment

OBJECTIVE: To propose a definition for stage IA1 cervical adenocarcinoma, based on the International Federation of Gynecology and Obstetrics (FIGO) staging system, and to determine if patients meeting criteria might be candidates for conservative surgery. METHODS: Two hundred women were diagnosed with early-stage cervical adenocarcinoma from 1982 to 1996. Histopathologic sections were reviewed by a gynecologic pathologist. Medical records were reviewed, and patients included in this study had microscopically identifiable lesions, up to 3 mm invasive depth, up to 7 mm tumor width, and negative margins if cone biopsy was performed. RESULTS: Twenty-one patients with microinvasive adenocarcinoma met criteria for FIGO stage IA1 carcinoma of the cervix. The median (range) follow-up was 76 (30-172) months and median (range) patient age was 38 (24-75) years. Definitive treatment included type II or III radical hysterectomy in 16 cases, simple abdominal or vaginal hysterectomy in four cases, and loop electrosurgical excision procedure in one case; one patient received adjuvant pelvic radiation. The histologic subtypes were endocervical adenocarcinoma in 18 cases, adenosquamous carcinoma in two cases, and clear-cell adenocarcinoma in one case. There was no evidence of parametrial invasion or lymph node metastases in any patient who had radical surgery, and there were no disease recurrences. CONCLUSION: Patients with microinvasive adenocarcinoma who met criteria for FIGO stage IA1 cervical carcinoma had disease limited to the cervix, and conservative surgery, such as cone biopsy or simple hysterectomy, might offer them definitive treatment.     

Clinical utility of human polymerized hemoglobin as a blood substitute after acute trauma and urgent surgery

We have previously documented the safety of 1 unit (50 gram) of human polymerized hemoglobin (Poly SFH-P) in healthy volunteers. This report describes the first patient trial to assess the therapeutic benefit of Poly SFH-P in acute blood loss. Thirty-nine patients received 1 (n = 14), 2 (n = 2), 3 (n = 15), or 6 (n = 8) units of Poly SFH-P instead of red cells as part of their blood replacement after trauma and urgent surgery. There were no safety issues related to the infusion of Poly SFH-P. The plasma hemoglobin concentration ([Hb]) after the infusion of 6 units (300 gram) of Poly SFH-P was 4.8 +/- 0.8 g/dL (mean +/- SD). Although the red cell [Hb] fell to 2.9 +/- 1.2 g/dL, the total [Hb] was maintained at 7.5 +/- 1.2 g/dL. Poly SFH-P maintained total [Hb], despite the marked fall in red cell [Hb] due to blood loss. The utilization of O2 (extraction ratio) was 27 +/- 16% from the red cells and 37 +/- 13% from the Poly SFH-P. Twenty-three patients (59%) avoided allogeneic transfusions during the first 24 hours after blood loss. Poly SFH-P effectively loads and unloads O2 and maintains total hemoglobin in lieu of red cells after acute blood loss, thereby reducing allogeneic transfusions. Poly SFH-P seems to be a clinically useful blood substitute.     

Oxygen permeability of Sr1-x Ce x Co0.2Fe0.8O3-δ ceramic membranes

Sr_1-x Ce _x Fe_0.8Co_0.2O_3-δ (x = 0, 0.05, 0.10, 0.15) ceramics were prepared by solid-state reactions, and their oxygen permeability was measured as a function of cerium content and membrane thickness at temperatures from 400 to 1000‡C and oxygen partial pressures from 10² to 10⁵ Pa. The oxygen permeability of the ceramics was found to decrease systematically with increasing Ce content. The oxygen transport was shown to be limited by volume diffusion. Doping of the ceramics with 20 wt % Ag notably improves their cracking resistance during thermal cycling.     

Using gas ducts made of glass-reinforced plastic for drawing off sulfur dioxide

A gas duct for sulfur dioxide in a unit for preparing sulfuric acid is studied under production conditions. A multilayer construction for the gas duct wall is considered and results are provided for examination of the gas duct inner and outer surfaces. Favorable experience is noted for the first year of controlled operation, i.e., the glass-reinforced plastic gas duct retains safety and reliability, and this guarantees a life (up to 19 years) predicted from the results of laboratory tests. __________ Translated from Khimicheskoe i Neftegazovoe Mashinostroenie, No. 6, pp. 48–49, June, 2007.     

A facility for studying the spatial and temporal characteristics of a plume produced by interaction of high-power CO<Subscript>2</Subscript> laser pulses with a solid-state target in various gas environments

An experimental facility for studying the kinetics of molecular association formation from atoms produced by evaporation of the target material by powerful CO₂ laser pulses is described. First experimental results are presented for the spectral and spatial-temporal characteristics of the spread of Al atoms produced in interactions of laser radiation with aluminum oxide Al₂O₃, followed by AlO formation in various low-pressure (0.1–0.3 Torr) atmospheres. Images of structurally similar forms condensed on a glass surface have been observed with an atomic-force microscope.     

Measurements of phantom scatter factors for small field sizes in high energy x rays

An alternate method to measure the phantom scatter factor in small fields is provided for high energy photon beams. The measurement technique is based on the density scaling theorem described by O'Connor [Phys. Med. Biol. 1, 352-369 (1957)]. The phantom scatter factor (Sp) is measured in balsa and cedar wood to give effective field sizes in 3 x 3 to 0.5 x 0.5 cm2 water. The extrapolated zero area phantom scatter factor from the average data of balsa and cedar is 0.45. This indicates that the variation of output is largely due to a sharp decrease in the phantom scatter factor for small field sizes.     

MR of the heart under pharmacologic stress

Magnetic resonance imaging is one method for assessing cardiac function and perfusion at rest and under stress conditions. In this article, the potential of stress magnetic resonance imaging for evaluating ischemic heart disease is reviewed, and technical aspects of some developments that may contribute to comprehensive magnetic resonance imaging assessment of heart disease under rest and stress are discussed.