Two-dimensional frustrated spin systems in high magnetic fields

We discuss our numerical results on the properties of the S = 1/2 frustrated J1-J2 Heisenberg model on a square lattice as a function of temperature and frustration angle phi = atan(J2/J1) in an applied magnetic field. We cover the full phase diagram of the model in the range -pi <= phi <= pi. The discussion includes the parameter dependence of the saturation field itself, and addresses the instabilities associated with it. We also discuss the magnetocaloric effect of the model and show how it can be used to uniquely determine the effective interaction constants of the compounds which were investigated experimentally.Comment: 4 pages, 5 figures, proceedings of RHMF 200

Giant nonlinear conduction and thyristor-like negative derivative resistance in BaIrO3 single crystals

We synthesized single-crystalline samples of monoclinic BaIrO3 using a molten flux method, and measured their magnetization, resistivity, Seebeck coefficient and nonlinear voltage-current characteristics. The magnetization rapidly increases below a ferromagnetic transition temperature TC of 180 K, where the resistivity concomitantly shows a hump-type anomaly, followed by a sharp increase below 30 K. The Seebeck coefficient suddenly increases below TC, and shows linear temperature dependence below 50 K. A most striking feature of this compound is that the anomalously giant nonlinear conduction is observed below 30 K, where a small current density of 20 A/cm2 dramatically suppresses the sharp increase in resistivity to induce a metallic conduction down to 4 K.Comment: 10 pages, 4 figures Submitted to Physical Review Letter

In vitro binding of single-stranded RNA by human Dicer

AbstractWhile Dicer alone has been shown to form stable complexes with double-stranded RNAs and short interfering RNAs, its interactions with single-stranded RNAs (ssRNAs) have not been characterized. Here, we show that recombinant human Dicer alone can bind 21-nt ssRNAs in vitro, independent of their sequence and structure. We also demonstrate that Dicer binds ssRNAs having a 5′-phosphate with greater affinity versus those with a 5′-hydroxyl. In addition, 3′-biotinylated ssRNAs are bound by Dicer with lower affinity than 3′-hydroxyl ssRNAs. The stability of ssRNA–Dicer complexes was found to depend on divalent cations. Together, our results suggest a role for the PAZ domain of Dicer in binding ssRNAs and may indicate roles for Dicer in cellular function beyond those currently known

Acute Burkitt\u27s Leukemia: Case Report and Literature Review

The occurrence of leukemia in Burkitt\u27s lymphoma, with or without visceral or nodal tumefaction is uncommon, and its initial presentation as leukemia is even more unusual. Because it has a poor chemotherapeutic response and a grave prognosis, it is important to recognize this unusual leukemia correctly. Our report describes the clinical and pathologic findings of Burkitt\u27s lymphoma cell leukemia in a five-year-old white boy who presented with abdominal distension, hepatosplenomegaly, and lymphadenopathy. Blood examination revealed normocytic normochromic anemia, erythroblastosis, slight leukocytosis, and the presence of numerous (24%) blasts. A diagnosis of Burkitt\u27s lymphoma was established on the basis of morphologic, cytochemical, and immunologic studies performed on the blasts. When the chemotherapy protocol for the lymphoma was administered, the patient responded well initially but suffered uric acid nephropathy, which was successfully treated. However, within two weeks he had a rapid relapse of leukemia and died four months after admission

Expression pattern of three-finger toxin and phospholipase A2 genes in the venom glands of two sea snakes, Lapemis curtus and Acalyptophis peronii: Comparison of evolution of these toxins in land snakes, sea kraits and sea snakes

10.1186/1471-2148-7-175BMC Evolutionary Biology7

Genetic diversity and population structure among isolates of the brown spot fungus, Bipolaris oryzae, as revealed by inter-simple sequence repeats (ISSR)

Bipolaris oryzae, the rice brown spot fungus is one of the pathological threats to rice crop worldwide. The genetic diversity among the Indian isolates of brown spot pathogen was studied using inter-simple sequence repeats (ISSR). Considerable intraspecific variability among the isolates of B. oryzae was revealed. Eighty-seven (87) highly reproducible fragments were amplified in all 69 isolates with an average of 13.8 markers per primer. Polymorphism range shown by ISSR primers was 83.33 to 95.45%, while the range of total loci scored was from 6 to 22. The molecular weight of scorable loci ranged from 150 to 2600 bp. The results obtained confirmed the genetic diversity of rice brown spot fungus among samples under study. The present study suggests that ISSR markers can be used as robust molecular markers for the population genetics, epidemiological and ecological studies of B. oryzae that will aid in designing improved methods for management of the rice brown spot disease.Keywords: Bipolaris oryzae, rice brown spot, inter-simple sequence repeats (ISSR), dendrogram, polymorphismAfrican Journal of Biotechnology, Vol. 13(2), pp. 238-244, 8 January, 201

Appearance of a double bubble in achalasia cardia: a case report

<p>Abstract</p> <p>Introduction</p> <p>Achalasia cardia is characterized by failure of the lower esophageal sphincter to relax in response to swallowing and by an absence of peristalsis in the esophageal body. Absence of a gastric air bubble is a well known radiological finding. Pneumatic balloon dilatation results in reappearance of the gastric bubble.</p> <p>Case presentation</p> <p>We report the case of a 43-year-old Indian man with achalasia cardia whose chest X-ray at the time of presentation showed an air bubble in the gastric region causing a diagnostic quandary. Successful dilatation of the lower esophageal sphincter resulted in the appearance of another air bubble in the gastric region. Proper analysis showed that the first bubble was actually a colonic air bubble of the splenic flexure and the appearance of the second bubble was the anticipated gastric air bubble.</p> <p>Conclusion</p> <p>In patients presenting with achalasia cardia, a colonic air bubble may be seen in the gastric region causing diagnostic difficulty. In these patients, a gastric air bubble may appear after pneumatic dilatation. At the end of the procedure, there will be two air bubbles ("double bubble"): a colonic and a gastric air bubble. To our knowledge, this finding has not been reported in the literature thus far.</p