Ultra-Low Temperature Magnetic Properties of Liquid 3He Films

We report measurements of the nuclear magnetization of submonolayer liquid ³ He films adsorbed on a graphite substrate (Papyex) preplated by a monolayer of ⁴ He. In the submilliKelvin temperature range we observe a substantial enhancement of the nuclear magnetization with respect to the degenerate Fermi Liquid value. The unusual temperature dependence of this new contribution to the liquid ³ He film magnetization agrees well with that expected from the theory of weak disorder in two-dimensional (2D) correlated Fermion systems. The effects of disorder and reduced dimensionality suppress the superfluid transition at least to below 180 K.     

Ultra-Low Temperature Susceptibility of a Highly Frustrated Two-Dimensional Solid 3He Magnet

We report the first measurement of the ultra-low temperature (200 ,K) susceptibility of a two-dimensional antiferromagnetic solid ³ He system, the 4/7 commensurate phase of ³ He/ ⁴ He/graphite. In the high temperature range the data has been analyzed using the series expansions of the Multiple-Spin-Exchange model. At ultra-low temperatures the susceptibility displays a very unusual temperature dependence, characteristic of a highly frustrated two-dimensional system.     

Leukocytes, cell adhesion molecules and ischemic acute renal failure

Ischemic acute renal failure (ARF) is a common clinical syndrome, associated with high morbidity and mortality, for which there is no specific therapy. Polymorphonuclear neutrophils (PMN) recruited during reperfusion have been implicated as mediators of renal parenchymal injury in ischemic ARF. Leukocyte adhesion molecules appear to facilitate PMN recruitment in this setting. Complementary studies using monoclonal antibodies, antisense oligonucleotides and gene "knock-out" indicate that blockade of CD11/CD18 integrins and intercellular adhesion molecule-1 (ICAM-1) attenuates ARF in some experimental models of renal ischemia. These exciting observations may herald the development of novel anti-adhesion strategies for use in human disease.     

Folic acid-enhanced synergy for the combination of trimetrexate plus the glycinamide ribonucleotide formyltransferase inhibitor 4-[2-(2-amino-4-oxo-4,6,7,8-tetrahydro-3H-pyrimidino[5,4,6][1,4]thiazin -6-yl)-(S)-ethyl]-2,5-thienoylamino-L-glutamic acid (AG2034): comparison across sensitive and resistant human tumor cell lines

Folic acid (PteGlu)-enhanced intense synergy has been observed between nonpolyglutamylatable dihydrofolate reductase (DHFR) inhibitors and polyglutamylatable inhibitors of other folate-requiring enzymes, such as glycinamide ribonucleotide formyltransferase (GARFT) and thymidylate synthase. Since this phenomenon is potentially therapeutically useful, we explored its universality by examining the combined action of a DHFR inhibitor, trimetrexate (TMQ), with a GARFT inhibitor, 4-[2-(2-amino-4-oxo-4,6,7,8-tetrahydro-3H-pyrimidino[5,4,6][1,4]++ +thiazin-6-yl)-(S)-ethyl]-2,5-thienoylamino-L-glutamic acid (AG2034), in eight human cultured cell lines. Using a 96-well plate cell growth inhibition assay, four ileocecal adenocarcinoma cell lines [HCT-8, HCT-8/DW2 (Tomudex-resistant), HCT-8/DF2 (Tomudex-/FdUrd-resistant), and HCT-8/50 (adapted to 50 nM PteGlu)], three head and neck carcinoma cell lines [A253, FaDu, and Hep-2/500 (FdUrd-resistant)], and a non-small cell lung carcinoma cell line [H460] were treated for 96 hr with TMQ + AG2034 in the presence of 23 or 40 microM PteGlu. Cell growth was measured with the sulforhodamine B assay at the end of this period. Drug interactions were assessed by fitting a 7-parameter model including a synergism parameter, alpha, to data with weighted nonlinear regression. Isobologram analysis was also applied. At 23 microM PteGlu, cells exhibited similar intensities of Loewe synergy for the combination of TMQ + AG2034. Loewe synergy was abolished in HCT-8/50 cells cultured and studied in 50 nM PteGlu. At 40 microM PteGlu, the intensity of the combined action in all cell lines was increased However, the most intense Loewe synergy was seen with HCT-8, HCT-8/DF2, H460, FaDu, A253, and Hep-2/500 cells, whereas the HCT-8/50 subculture showed less of the phenomenon, and PteGlu enhancement was the least with HCT-8/DW2, a subline deficient in folylpolyglutamate synthetase (FPGS). The universality of the PteGlu-enhanced intense synergy phenomenon is suggested. Impaired FPGS activity and low-folate adaptation prior to treatment significantly lessen the degree of PteGlu enhancement.     

Enhanced continent mechanism of tapered ileum by extramural support from pouch-abdominal wall: an experimental study in dogs

PURPOSE: To construct a reliable continent tube, which is easy to catheterize, we created and evaluated a new continent cutaneous diversion using a tapered ileum combined with extramural support from the pouch-abdominal wall. MATERIALS AND METHODS: Six dogs underwent a procedure in which two ileal segments were tapered and anastomosed to the ileal pouch. One of the segments (continent) was placed between the back surface of the rectus muscle and the wall of the ileal pouch creating a continent tube. The other segment (control) was brought out into the abdominal skin directly without any support from the pouch-abdominal wall. Urodynamic and radiological studies were carried out postoperatively in all dogs. RESULTS: In the continent tubes, the maximum closure pressure with a full pouch was significantly higher than those with an empty pouch (p<0.01). The maximum closure pressures of the continent tubes were significantly higher than those of the control tubes when the pouch was empty (p<0.01). The leak point pressures of the continent tubes were significantly higher than those of the control tubes (p<0.001). In all dogs, the retrograde radiogram of the continent tubes showed perfect canalization without stenosis. CONCLUSION: This study suggests that the continent mechanism of tapered ileum can be greatly enhanced by fixing it between the abdominal and pouch walls, also allowing easy catheterization in contrast to the submucosal tunnel technique.     

INTERLAYER COUPLING AND FERROMAGNETIC RESONANCE IN Fe-Si/Cr MULTILAYERS

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Discrete Calabi Flow: A Unified Conformal Parameterization Method

Conformal parameterization for surfaces into various parameter domains is a fundamental task in computer graphics. Prior research on discrete Ricci flow provided us with promising inspirations from methods derived via Riemannian geometry, which is rigorous in theory and effective inpractice. In this paper, we propose a unified conformal parameterization approachfor turning triangle meshes into planar and spherical domains using discrete Calabi flow onpiecewise linear metric. We incorporate edge‐flipping surgery to guarantee convergence as well as other significant improvements including approximate Newton's method, optimal step‐lengths, priority embedding and boundary customizing, which achieve better performance and functionality with robustness and accuracy.     

Dependence of the efficiency of Raman scattering in silicon nanowire arrays on the excitation wavelength

The features of Raman scattering in layers of silicon nanowires from 50 to 350 nm in diameter, obtained by the chemical etching of crystalline silicon (c-Si) wafers with preliminarily deposited silver nanoparticles in fluoric acid solutions are studied. c-Si wafers with various crystallographic orientations and doping levels are used, which is conditioned by the different sizes and degrees of ordering of the formed nanostructures. It is found that the radiation of the Raman scattering of samples is depolarized, and its efficiency depends strongly on the excitation wavelength. Upon excitation by light with a wavelength of 1064 nm, the ratio of Raman-scattering intensities of silicon nanowire samples and c-Si is 2 to 5; as the wavelength decreases, this ratio increases for structures with larger silicon-nanowire diameters and higher degrees of ordering and decreases for less ordered structures. The results obtained are explained by the effect of partial light localization in silicon nanowire arrays.     

The significance of soluble interleukin-2 receptor in monitoring disease relapse in patients with nasopharyngeal cancer

BACKGROUND: Soluble interleukin-2 receptor alpha (sIL-2R alpha) is a well-known indicator of T-cell activation noted to be increasing in nasopharyngeal cancer. However, the significance of sIL-2R alpha in monitoring disease relapse is unclear. This study was initiated to address this issue. METHODS: Serum of 56 patients with NPC, which underwent either primary, salvage, or palliative treatments, from 1992 to 1993 at the Cancer Center, Veterans General Hospital-Taipei, were collected from our serum bank. According to their disease status at the time of study, at least two years after last treatments, the 56 patients were divided into four groups. The remission group represented those in remission at the time of study (n = 24). The metastasis group represented those with distant metastasis present at the time of study (n = 17). The recurrence group represented those with locoregional recurrence present at the time of study (n = 11). The combined group represented those with locoregional recurrence as well as distant metastasis (n = 4). The seral sIL-2R alpha concentrations of the 56 NPC patients were determined with enzyme-linked immunoabsorbent assay. The combined group was excluded in our statistical analysis. We performed statistical analysis on the differences of paired serum sIL-2R alpha concentrations between different periods of the diseases. The first analysis was on the differences of sIL-2R alpha concentrations between diagnosis and post-radiotherapy periods for 13 out of 24 patients in the remission group and 7 out of 11 patients in the recurrence group. The second analysis was on the differences of sIL-2R alpha concentration between follow-up before detection-of-relapse and after detection-of-relapse for 5 out of 17 patients in the metastasis group and six out of 11 patients in the recurrence group. RESULTS: The first statistical analysis revealed no significant differences of sIL-2R alpha concentrations for the remission group (P = 0.946) and the recurrence group (P = 0.156) between diagnosis and post-radiotherapy periods. The second statistical analysis revealed no significant differences of sIL-2R alpha concentrations between before and after detection-of-relapse for the recurrence group, neither (P = 0.438). The results for the metastasis group were different. The sIL-2R alpha concentrations were shown to increase after the detection of metastasis for the 5 paired samples from the metastasis group, although the Wilcoxon signed ranks test on the differences only showed borderline significance (P = 0.063). CONCLUSIONS: Our findings show that sIL-2R alpha would be of no value in monitoring the development of locoregional recurrence but might be useful in monitoring distant metastasis. Although our current limited data did not provide strong support for the role of sIL-2R alpha in monitoring metastasis, it might be delineated in the future by collecting more data.     

Susceptibility to esophageal cancer and genetic polymorphisms in glutathione S-transferases T1, P1, and M1 and cytochrome P450 2E1

Genetic polymorphisms in enzymes involved in carcinogen metabolism have been shown to influence susceptibility to cancer. Cytochrome P450 2E1 (CYP2E1) is primarily responsible for the bioactivation of many low molecular weight carcinogens, including certain nitrosamines, whereas glutathione S-transferases (GSTs) are involved in detoxifying many other carcinogenic electrophiles. Esophageal cancer, which is prevalent in China, is hypothesized to be related to environmental nitrosamine exposure. Thus, we conducted a pilot case-control study to examine the association between CYP2E1, GSTM1, GSTT1, and GSTP1 genetic polymorphisms and esophageal cancer susceptibility. DNA samples were isolated from surgically removed esophageal tissues or scraped esophageal epithelium from cases with cancer (n = 45), cases with severe epithelial hyperplasia (n = 45), and normal controls (n = 46) from a high-risk area, Linxian County, China. RFLPs in the CYP2E1 and the GSTP1 genes were determined by PCR amplification followed by digestion with RsaI or DraI and Alw26I, respectively. Deletion of the GSTM1 and GSTT1 genes was examined by a multiplex PCR. The CYP2E1 polymorphism detected by RsaI was significantly different between controls (56%) and cases with cancer (20%) or severe epithelial hyperplasia (17%; P < 0.001). Persons without the RsaI variant alleles had more than a 4-6-fold risk of developing severe epithelial hyperplasia (adjusted odds ratio, 6.0; 95% confidence interval, 2.3-16.0) and cancer (adjusted odds ratio, 4.8; 95% confidence interval, 1.8-12.4). Polymorphisms in the GSTs were not associated with increased esophageal cancer risk. These results indicate that CYP2E1 may be a genetic susceptibility factor involved in the early events leading to the development of esophageal cancer.