Prevalence and genetic characterization of Cryptosporidium spp. In diarrheic children from Gonbad Kavoos city, Iran

Background: Cryptosporidium is an intestinal protozean parasite causing water-borne and foodborne outbreaks of diarrheal diseases. The present study was per-formed in order to find prevalence and subtypes of Cryptosporidium among children with diarrhea in Gonbad Kavoos City, Northern Iran. Methods: Diarrheic samples were collected from 547 children. The initial parasi-tological diagnosis was made based on detection of oocysts using the modified Ziehl-Neelsen acid-fast staining method. The positive microscopically samples were selected for sequence analysis of partial 60 kDa glycoprotein (gp60) gene. Results: Out of 547 collected samples, 27 (4.94) were positive for Cryptosporid-ium oocysts. Fifteen from 27 positive samples successfully amplified in PCR. Se-quences analysis of gp60 gene in 15 Cryptosporidium isolates revealed that all of them (100) were C. parvum. The results showed three subtypes of IIa subtype family (7 cases) including IIaA16G2R1, IIaA17G1R1, IIaA22G3R1 and one subtype of IId subtype family (8 cases). The most common allele was IId A17G1d (53.3). Conclusion: The predominance of zoonotic subtype families of C. parvum species (IIa, IId) in the present study is in concordance with previous studies in Iran and emphasizes the significance of zoonotic transmission of cryptosporidiosis in the country. © 2015, Tehran University of Medical Sciences (TUMS). All rights Reserved

Effect of subchronic administration of aqueous Artemisia annua extract on α1-adrenoceptor agonist-induced contraction of isolated aorta in rat

Artemisia species, growing in almost all the northern hemisphere, is used in folk medicine of some countries as a remedy for hypertension. Since some cardiovascular disorders including hypertension are accompanied with altered responsiveness of vascular alpha-adrenergic receptors, the effect of aqueous Artemisia annua extract (100 and 200 mg kg-1) on α1- adrenoceptor agonist-induced contraction of rat aorta was investigsted. After 4 weeks, the contraction and endothelium-dependent and -independent relaxation response of extract-treated rats were recorded. The results showed that the contractile response of aortic rings with endothelium to phenylephrine in extract-treated rats decreases (P<0.1-0001) and their endothelium-dependent relaxation response to acetylcholine increases (P<0.01-0.001) significantly in comparison with controls. Endothelium-denuded aortic rings from extract-treated rats also showed a significant decrease (P<0.05) in contractile response, but there was no considerable difference in their endothelium-independent relaxation response to isosorbide dinitrate. These data suggest that the aqueous extract of Artemisia annua could attenuate contractile response and enhance the endothelium-dependent relaxation response of aortic rings from normal rats

Perfect Reflection of Light by an Oscillating Dipole

We show theoretically that a directional dipole wave can be perfectly reflected by a single point-like oscillating dipole. Furthermore, we find that in the case of a strongly focused plane wave up to 85 % of the incident light can be reflected by the dipole. Our results hold for the full spectrum of the electromagnetic interactions and have immediate implications for achieving strong coupling between a single propagating photon and a single quantum emitter.Comment: 3 figure

Molecular Epidemiology of Cryptosporidiosis in Iranian Children, Tehran, Iran

Background: Cryptosporidium is a worldwide protozoan parasite and one of the most common causes of infection and diarrhea in humans and cattle. The aim of the present study was determina­tion of subtypes of Cryptosporidium among children with diarrhea in Tehran by se­quence analysis of the highly polymorphic 60-kDa glycoprotein (GP60) gene.Methods: Fecal samples were collected from 794 diarrheic children. Initial identification of Crypto­spo­ridium was carried out on stool samples by Ziehl-Neelsen acid-fast staining method. DNA was extracted from positive microscopically samples and Cryptosporidium genotypes and subtypes were determined, accordingly."nResults: Out of 794 collected samples, 19 (2.40 %) were positive for Cryptosporidium oocysts. Sequences analysis of GP60 gene showed that 17 (89.47 %) of the positive isolates were Crypto­spori­dium parvum and 2 (10.52 %) were C. hominis. All subtypes of C. parvum isolates belonged to allele families IIa (6/17) and IId (11/17). The most common allele in all 17 isolates belonged to IId A20G1a (41.18%). A22G1 (IF) subtype was detected in two C. hominis isolates of the chil­dren."nConclusion: The predominancy of C. parvum species (specially, IId A20G1a sub­type) in current study underlines the importance of zoonotic Cryptosporidium transmission in Iran

Oncogenic role of connective tissue growth factor is associated with canonical TGF-β cascade in colorectal cancer

TGF-β signaling pathways promote tumour development and control several downstream genes such as CTGF and MMPs. This study aimed to investigate the association between CTGF and MMP-1 mRNA expressions with clinicopathological status and survival rate in colorectal cancer patients. We investigated expression levels of CTGF and MMP-1 genes in paraffin-embedded tumours and adjacent normal tissue blocks (ADJ) by Real Time-PCR. Then, the expression of Smad2 and Smad4 proteins in the TGF-β canonical pathway was evaluated by immunohistochemistry. Finally, the correlation between CTGF, MMP-1, and the canonical TGF-β-signalling pathway with the clinicopathological features was investigated. Expression levels of MMP-1and CTGF were higher in tumours compared with adjacent normal tissues. Overexpression levels of MMP-1 and CTGF were associated with lymph node metastasis, distant metastasis, tumour histopathological grading, advanced stage, and poor survival (p 0.05). Additionally, a significant association between the upregulation of MMP-1 and tumour location was noted. Upregulation of Smad2 and Smad4 proteins were also significantly correlated with lymph node metastasis, distant metastasis, advanced stage, and poor survival (p 0.0001). This study showed that canonical TGF-β signalling regulates both CTGF and MMP-1 expression and CRC progression. Moreover, TGF-β signalling and its downstream genes could be used as novel biomarkers and novel approaches for targeted therapy in CRC

Kinetic investigation on extrinsic spin Hall effect induced by skew scattering

The kinetics of the extrinsic spin Hall conductivity induced by the skew scattering is performed from the fully microscopic kinetic spin Bloch equation approach in $(001)$ GaAs symmetric quantum well. In the steady state, the extrinsic spin Hall current/conductivity vanishes for the linear-$\mathbf k$ dependent spin-orbit coupling and is very small for the cubic-$\mathbf k$ dependent spin-orbit coupling. The spin precession induced by the Dresselhaus/Rashba spin-orbit coupling plays a very important role in the vanishment of the extrinsic spin Hall conductivity in the steady state. An in-plane spin polarization is induced by the skew scattering, with the help of the spin-orbit coupling. This spin polarization is very different from the current-induced spin polarization.Comment: 5 pages, 2 figures, to be published in JPC

Nanoscale temperature measurements using non-equilibrium Brownian dynamics of a levitated nanosphere

Einstein realised that the fluctuations of a Brownian particle can be used to ascertain properties of its environment. A large number of experiments have since exploited the Brownian motion of colloidal particles for studies of dissipative processes, providing insight into soft matter physics, and leading to applications from energy harvesting to medical imaging. Here we use optically levitated nanospheres that are heated to investigate the non-equilibrium properties of the gas surrounding them. Analysing the sphere's Brownian motion allows us to determine the temperature of the centre-of-mass motion of the sphere, its surface temperature and the heated gas temperature in two spatial dimensions. We observe asymmetric heating of the sphere and gas, with temperatures reaching the melting point of the material. This method offers new opportunities for accurate temperature measurements with spatial resolution on the nanoscale, and a new means for testing non-equilibrium thermodynamicsComment: 5 pages, 4 figures, supplementary material available upon reques

How close can one approach the Dirac point in graphene experimentally?

The above question is frequently asked by theorists who are interested in graphene as a model system, especially in context of relativistic quantum physics. We offer an experimental answer by describing electron transport in suspended devices with carrier mobilities of several 10^6 cm^2V^-1s^-1 and with the onset of Landau quantization occurring in fields below 5 mT. The observed charge inhomogeneity is as low as \approx10^8 cm^-2, allowing a neutral state with a few charge carriers per entire micron-scale device. Above liquid helium temperatures, the electronic properties of such devices are intrinsic, being governed by thermal excitations only. This yields that the Dirac point can be approached within 1 meV, a limit currently set by the remaining charge inhomogeneity. No sign of an insulating state is observed down to 1 K, which establishes the upper limit on a possible bandgap

Interplay between edge states and simple bulk defects in graphene nanoribbons

We study the interplay between the edge states and a single impurity in a zigzag graphene nanoribbon. We use tight-binding exact diagonalization techniques, as well as density functional theory calculations to obtain the eigenvalue spectrum, the eigenfunctions, as well the dependence of the local density of states (LDOS) on energy and position. We note that roughly half of the unperturbed eigenstates in the spectrum of the finite-size ribbon hybridize with the impurity state, and the corresponding eigenvalues are shifted with respect to their unperturbed values. The maximum shift and hybridization occur for a state whose energy is inverse proportional to the impurity potential; this energy is that of the impurity peak in the DOS spectrum. We find that the interference between the impurity and the edge gives rise to peculiar modifications of the LDOS of the nanoribbon, in particular to oscillations of the edge LDOS. These effects depend on the size of the system, and decay with the distance between the edge and the impurity.Comment: 10 pages, 15 figures, revtex