118 research outputs found
Patterns of Striped order in the Classical Lattice Coulomb Gas
We obtain via Monte Carlo simulations the low temperature charge
configurations in the lattice Coulomb gas on square lattices for charge filling
ratio in the range . We find a simple regularity in the low
temperature charge configurations which consist of a suitable periodic
combination of a few basic striped patterns characterized by the existence of
partially filled diagonal channels. In general there exist two separate
transitions where the lower temperature transition () corresponds to the
freezing of charges within the partially filled channels. is found to be
sensitively dependent on through the charge number density within the channels.Comment: 4 pages, 8 figure
Chemicals Facilitating Reprogramming: Targeting the SAM Binding Site to Identify Novel Methyltransferase Inhibitors
© 2014 John Wiley & Sons, Ltd. Reprogramming of somatic cells to a pluripotent state has been achieved by viral-mediated transduction of defined transcription factors. In order to achieve the goal of clinical application, it is necessary to overcome a variety of limitations, including poor reprogramming efficiencies and viral integration. One strategy is to identify small-molecule inhibitors that can improve reprogramming efficiency or replace defined transcription factors. Several reports have demonstrated that modulation of chromatin-modifying enzymes can significantly improve reprogramming efficiency. Key enzymes include DNA and histone methyltransferases, which utilize the cofactor S-adenosyl methionine (SAM) to transfer a methyl group. In this chapter, we review our efforts to identify SAM analogues by virtual screening
Prevalence of the Intestinal Flukes Haplorchis taichui and H. yokogawai in a Mountainous Area of Phongsaly Province, Lao PDR
Phongsaly Province, located in the northernmost area of Lao PDR, was previously suggested to be endemic for the liver fluke Opisthorchis viverrini infection. To confirm, or rule out, this suggestion, the Phonxay village in the Khoua District, Phongsaly Province, was selected for a survey. Ten volunteers (8 men and 2 women aged 31-57 years) who consumed raw freshwater fish and had gastrointestinal troubles were treated with a single dose of praziquantel (40 mg/kg) and pyrantel pamoate (10 mg/kg) and purged with magnesium sulfate to recover any worm parasites. Eight of the 10 volunteers expelled 1 or more species of trematodes, nematodes, or cestodes (worm positive rate; 80%). The worms were morphologically identified as H. taichui (861 worms from 8 people), H. yokogawai (59 from 6 people), Phaneropsolus bonnei (1 from 1 person), Trichostrongylus sp. (2 from 2 people), Ascaris lumbricoides (2 from 1 person), Enterobius vermicularis (11 from 3 people), and Taenia saginata (1 strobila with scolex from 1 person). The results indicate that the mountainous area of Phongsaly Province, Lao PDR, is not endemic for the liver fluke but endemic for intestinal flukes, in particular, Haplorchis taichui and H. yokogawai
Morphologic and Genetic Identification of Taenia Tapeworms in Tanzania and DNA Genotyping of Taenia solium
Species identification of Taenia tapeworms was performed using morphologic observations and multiplex PCR and DNA sequencing of the mitochondrial cox1 gene. In 2008 and 2009, a total of 1,057 fecal samples were collected from residents of Kongwa district of Dodoma region, Tanzania, and examined microscopically for helminth eggs and proglottids. Of these, 4 Taenia egg positive cases were identified, and the eggs were subjected to DNA analysis. Several proglottids of Taenia solium were recovered from 1 of the 4 cases. This established that the species were T. solium (n=1) and T. saginata (n=3). One further T. solium specimen was found among 128 fecal samples collected from Mbulu district in Arusha, and this had an intact strobila with the scolex. Phylegenetic analysis of the mtDNA cox1 gene sequences of these 5 isolates showed that T. saginata was basal to the T. solium clade. The mitochondrial cox1 gene sequences of 3 of these Tanzanian isolates showed 99% similarity to T. saginata, and the other 2 isolates showed 100% similarity to T. solium. The present study has shown that Taenia tapeworms are endemic in Kongwa district of Tanzania, as well as in a previously identified Mbulu district. Both T. solium isolates were found to have an "African/Latin American" genotype (cox1)
Structural Relaxation, Self Diffusion and Kinetic Heterogeneity in the Two Dimensional Lattice Coulomb Gas
We present Monte Carlo simulation results on the equilibrium relaxation
dynamics in the two dimensional lattice Coulomb gas, where finite fraction
of the lattice sites are occupied by positive charges. In the case of high
order rational values of close to the irrational number
( is the golden mean), we find that the system
exhibits, for wide range of temperatures above the first-order transition, a
glassy behavior resembling the primary relaxation of supercooled liquids.
Single particle diffusion and structural relaxation show that there exists a
breakdown of proportionality between the time scale of diffusion and that of
structural relaxation analogous to the violation of the Stokes-Einstein
relation in supercooled liquids. Suitably defined dynamic cooperativity is
calculated to exhibit the characteristic nature of dynamic heterogeneity
present in the system.Comment: 12 pages, 20 figure
Role of spinon and spinon singlet pair excitations on phase transitions in superconductors
We examine the roles of massless Dirac spinon and spin singlet pair
excitations on the phase transition in superconductors. Although the
massless spinon excitations in the presence of the spin singlet pair
excitations do not alter the nature of the phase transition at , that
is, the XY universality class, they are seen to induce an additional attractive
interaction potential between vortices, further stabilizing vortex-antivortex
pairs at low temperature for lightly doped high samples.Comment: 5 pages, 1 figur
Effect of Control Strategies on Prevalence, Incidence and Re-infection of Clonorchiasis in Endemic Areas of China
Clonorchiasis is a liver fluke disease prevalent in East Asia, which is transmitted to humans mainly by eating raw freshwater fish. It induces various complications in the liver or bile duct including cholelithiasis, cholecystitis, cholangitis, and cirrhosis. Clonorchis sinensis has been known to cause cholangiocarcinoma, and is still a major health problem in endemic areas. People in endemic areas are repeatedly infected with C. sinensis, as they continue to consume raw freshwater fish in spite of control activities and availability of a highly effective drug, praziquantel. Reservoir hosts such as cats, dogs, and pigs supply eggs continuously to the environment and act as a source of infection. The present study analyzed the data produced by the Korea-China collaborative project for helminthiasis control in China during 2001–2004 to find out effective chemotherapeutic control strategies with praziquantel in endemic areas and to evaluate their effects on the transmission of C. sinensis infection by repeated mass or selective treatment. The four-year control trial found that repeated treatment is essential to the effective reduction of prevalence and infection intensity in heavily endemic areas. Mass chemotherapy is more effective than selective treatment, and more repeated treatments produce better outcomes in clonorchiasis control. Health education to change the habit of consuming raw or undercooked fish is an important and practical measure to prevent and reduce human infections in endemic areas. Together with chemotherapy, health education could be highly effective and produce sustainable effects in clonorchiasis control. Treatment of reservoirs, if applicable, will contribute to reduce the source of infection
Driven Diffusion in the Two-Dimensional Lattice Coulomb Gas; A Model for Flux Flow in Superconducting Networks
We carry out driven diffusion Monte Carlo simulations of the two dimensional
classical lattice Coulomb gas in an applied uniform electric field, as a model
for vortex motion due to an applied d.c. current, in a periodic superconducting
network. A finite-size version of dynamic scaling is used to extract the
dynamic critical exponent z, and infer the non-linear response at the
transition temperature. We consider the f=0 and f=1/2 cases, corresponding to
no applied magnetic field, and to one half flux quantum per unit cell of the
network respectively.Comment: 25 pages, 7 figures (available from [email protected]),
RevTex3.0, URST12
Critical Exponents of the Fully Frustrated 2-D Xy Model
We present a detailed study of the critical properties of the 2-D XY model
with maximal frustration in a square lattice. We use extensive Monte Carlo
simulations to study the thermodynamics of the spin and chiral degrees of
freedom, concentrating on their correlation functions. The gauge invariant
spin-spin correlation functions are calculated close to the critical point for
lattice sizes up to ; the chiral correlation functions are
studied on lattices up to . We find that the critical exponents of
the spin phase transition are , and , which are to be
compared with the unfrustrated XY model exponents and . We
also find that the critical exponents of the chiral transition are
, , , and
, which are different from the expected 2-D Ising
critical exponents. The spin-phase transition occurs at which
is about 7\% above the estimated chiral critical temperature . However, because of the size of the statistical errors, it is
difficult to decide with certainty whether the transitions occur at the same or
at slightly different temperatures. Finally, the jump in the helicity modulus
in the fully frustrated system is found to be about 23\% below the unfrustrated
universal value. The most important consequence of these results is that the
fully frustrated XY model appears to be in a novel universality class. Recent
successful comparisons of some of these results with experimental data are also
briefly discussed. (TO APPEAR IN PRB)Comment: 47 pages (PHYZZX
Developmental Transcriptomic Features of the Carcinogenic Liver Fluke, Clonorchis sinensis
Clonorchis sinensis is the causative agent of the life-threatening disease endemic to China, Korea, and Vietnam. It is estimated that about 15 million people are infected with this fluke. C. sinensis provokes inflammation, epithelial hyperplasia, and periductal fibrosis in bile ducts, and may cause cholangiocarcinoma in chronically infected individuals. Accumulation of a large amount of biological information about the adult stage of this liver fluke in recent years has advanced our understanding of the pathological interplay between this parasite and its hosts. However, no developmental gene expression profiles of C. sinensis have been published. In this study, we generated gene expression profiles of three developmental stages of C. sinensis by analyzing expressed sequence tags (ESTs). Complementary DNA libraries were constructed from the adult, metacercaria, and egg developmental stages of C. sinensis. A total of 52,745 ESTs were generated and assembled into 12,830 C. sinensis assembled EST sequences, and then these assemblies were further categorized into groups according to biological functions and developmental stages. Most of the genes that were differentially expressed in the different stages were consistent with the biological and physical features of the particular developmental stage; high energy metabolism, motility and reproduction genes were differentially expressed in adults, minimal metabolism and final host adaptation genes were differentially expressed in metacercariae, and embryonic genes were differentially expressed in eggs. The higher expression of glucose transporters, proteases, and antioxidant enzymes in the adults accounts for active uptake of nutrients and defense against host immune attacks. The types of ion channels present in C. sinensis are consistent with its parasitic nature and phylogenetic placement in the tree of life. We anticipate that the transcriptomic information on essential regulators of development, bile chemotaxis, and physico-metabolic pathways in C. sinensis that presented in this study will guide further studies to identify novel drug targets and diagnostic antigens
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