Ising transition in a one-dimensional quarter-filled electron system with dimerization

We examine critical properties of the quarter-filled one-dimensional Hubbard model with dimerization and with the onsite and nearest-neighbor Coulomb repulsion U and V. By utilizing the bosonization method, it is shown that the system exhibits an Ising quantum phase transition from the Mott insulating state to the charge-ordered insulating state. It is also shown that the dielectric permittivity exhibits a strong enhancement as decreasing temperature with power-law dependence at the Ising critical point.Comment: 8 pages, 1 figure, uses elsart.cls, Proc. Int. Symp. ISSP-Kashiwa 2001, submitted to J. Phys. Chem. Solid

Crossover from Quarter-Filling to Half-Filling in a One-Dimensional Electron System with a Dimerized and Quarter-Filled Band

The interplay between quarter-filled and half-filled umklapp scattering has been examined by applying the renormalization group method to a one-dimensional quarter-filled electron system with dimerization, on-site (U) and nearest-neighbor (V) repulsive interactions. The phase diagram on the U-V plane is obtained at absolute zero temperature where the Mott insulator (the charge ordered insulator) is found for smaller (larger) V. By choosing the moderate parameter in the region of Mott insulator, it is shown that the resistivity exhibits a crossover from behavior of quarter-filling to that of half-filling with decreasing temperature.Comment: 4 pages, 4 figures, submitted to J. Phys. Soc. Jp

Acral-type Malignant Acanthosis Nigricans Associated with Gastric Adenocarcinoma

Acanthosis nigricans is a symmetric eruption characterized by the presence of a hyperpigmented, velvety cutaneous thickening, that can develop on any part of the body, but characteristically affects the flexural areas of the body. The velvety hyperkeratotic lesions can be located on the dorsum of the hands and feet in dark-skinned people in the form of a variant of acanthosis nigricans called as acral acanthotic anomaly or acral type acanthosis nigricans. Although acanthosis nigricans is associated with malignant tumors, particularly gastric carcinoma, acral type acanthosis nigricans has never been reported to be associated with gastric adenocarcinoma. In our present study, we describe a case of 58-year-old man with acral type acanthosis nigricans and its association with carcinoma of the stomach; a marked improvement was seen in the skin condition of the patient with chemotherapy

Treatment of Disseminated Classic Type of Kaposi's Sarcoma with Paclitaxel

Classic Kaposi sarcoma (KS) is a rare human herpes virus 8-associated angioproliferative disease, and the disseminated classic type of KS in Korea is even rarer. The treatment options for classic KS vary and range from surgical excision to ionizing irradiation or chemotherapy. Recently, there have been a few reports of treating classic KS with paclitaxel, which has been used to treat AIDS-associated KS and post-transplant KS. We herein report a case of disseminated classic type KS in a 78-year-old Korean male patient who showed dramatic response after only two cycles of paclitaxel treatment

Aldosterone-Producing Adrenocortical Carcinoma without Hypertension

Although adrenocortical tumors are common, adrenocortical carcinomas are rare. Moreover, aldosterone-producing adrenocortical carcinomas without hypertension are exceedingly rare, with only two previously reported cases

Spin-Density-Wave Phase Transitions in Quasi-One-Dimensional Dimerized Quarter-Filled Organic Conductors

We have studied spin density wave (SDW) phase transitions in dimerized quarter-filled Hubbard chains weakly coupled via interchain one-particle hopping, $t_{b0}$. It is shown that there exists a critical value of $t_{b0}$, $t_{b}^\ast$, between the incoherent metal regime ($t_{b0}<t_{b}^\ast$) and the Fermi liquid regime ($t_{b0}>t_{b}^\ast$) in the metallic phase above the SDW transition temperature. By using the 2-loop perturbative renormalization-group approach together with the random-phase-approximation, we propose a SDW phase diagram covering both of the regimes. The SDW phase transition from the incoherent metal phase for $t_{b0}<t_{b}^\ast$ is caused by growth of the intrachain electron-electron umklapp scattering toward low temperatures, which is regarded as preformation of the Mott gap. We discuss relevance of the present result to the SDW phase transitions in the quasi-one-dimensional dimerized quarter-filled organic conductors, (TMTTF)$_2$X and (TMTSF)$_2$X.Comment: 19 pages, 13 eps figures, uses jpsj.sty, corrected typo in the text and figures, no changes to the paper, to appear in J. Phys. Soc. Jpn. 68, No.8 (1999

Metastatic Gastric Adenocarcinoma Presenting as a Solitary Plaque on the Palm

Cutaneous metastases from gastric adenocarcinoma are extremely rare. When present, metastasis typically signifies disseminated disease with a poor prognosis. We report a case of an 80-year-old male with gastric cancer who presented with a single, erythematous plaque on the left palm, a very rare site for skin metastasis. Results of a skin biopsy demonstrated that the cutaneous metastasis originated from the stomach. This report emphasized the need for appropriate investigation into newly appearing, unusual, or persistent skin lesions

Overexpression of the AtLOS5 gene increased abscisic acid level and drought tolerance in transgenic cotton

Drought is the major environmental stress that limits cotton (Gossypium hirsutum L.) production worldwide. LOS5/ABA3 (LOS5) encodes a molybdenum co-factor and is essential for activating aldehyde oxidase, which is involved in abscisic acid (ABA) biosynthesis. In this study, a LOS5 cDNA of Arabidopsis thaliana was overexpressed in cotton cultivar Zhongmiansuo35 (Z35) by Agrobacterium tumefaciens-mediated transformation. The transformation and overexpression of AtLOS5 were assessed by PCR and RT-PCR analysis. Detached shoots of transgenic cotton showed slower transpirational water loss than those of Z35. When pot-grown 6-week-old seedlings were withheld from watering for 3 d, transgenic cotton accumulated 25% more endogenous ABA and about 20% more proline than Z35 plants. The transgenic plants also showed increased expression of some drought-responding genes such as P5CS and RD22, and enhanced activity of antioxidant enzymes such as superoxide dismutase, peroxidase, and ascorbate peroxidase. Their membrane integrity was considerably improved under water stress, as indicated by reduced malondialdehyde content and electrolyte leakage relative to control plants. When the pot-grown plants were subjected to deficit irrigation for 8 weeks (watering to 50% of field capacity), transgenic plants showed a 13% increase in fresh weight than the wild type under the same drought condition. These results suggest that the AtLOS5 transgenic cotton plants acquired a better drought tolerance through enhanced ABA production and ABA-induced physiological regulations

Acrodermatitis Enteropathica-like Eruption Associated with Combined Nutritional Deficiency

We present here a case of acrodermatitis enteropathica-like eruption associated with essential free fatty acid and protein deficiencies as well as borderline zinc deficiency that occurred after Whipple's operation in a 31-yr-old woman. Her eruptions were improved not by zinc supplements alone, but her condition was improved by total parenteral nutrition including amino acids, albumin, lipid and zinc. Although we could not exactly decide which of the nutrients contributed the most to her manifestations, we inferred that all three elements in concert caused her dermatoses. This case shows that even though the patient's skin manifestations and laboratory results are suggestive of acrodermatitis enteropathica, the physicians should keep in mind the possibility that this disease can be associated with other nutritional deficiencies such as free fatty acid or protein deficiency