Estimation of phase signal change in neuronal current MRI for evoke response of tactile detection with realistic somatosensory laminar network model

Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm³. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation.     

Floating Index Metacarpal Associated with Multiple Carpometacarpal Fracture-Dislocations: a Case Report

The floating metacarpal bone is a result of simultaneous fracture-dislocation of both carpometacarpal and metacarpophalangeal joints. This rare entity may be associated with other hand injuries. Here we present a floating index metacarpal with concomitant 3rd–5th carpometacarpal fracture-dislocations. Excellent functional short-term result was achieved after open metacarpopha langeal reduction and closed carpometacarpal reduction and percutaneous pinning.     

Prevalence of human papillomavirus in esophageal carcinoma in Tangshan,China

AIM:to study the prevalence of human papillomavirus(HPV) in esophageal carcinoma in tangshan,China,a high-incidence area.METHODS:Formalin-fixed,paraffin-embedded tissue specimens from 198 patients who were pathologically diagnosed with esophageal squamous cell carcinoma from 2011 to 2013 were obtained from a pathology department in Tangshan.DNA was extracted from all198 specimens to detect HPV by polymerase chain reaction(PCR).β-globin PCR was performed to check the quality of the DNA extraction procedure.PCR was performed to detect a wide range of HPV types,and type-specific PCR was performed to detect HPV types16 and 18.Negative and positive controls were used for HPV 16 and 18 detection.RESULTS:the DNA extraction method in this study appeared to be more effective than other previously reported methods.After DNA extraction,more than98%of the tissue specimens had an acceptable result in the DNA qualification test(β-globin PCR).the overall prevalence of HPV in tumor tissues by GP6+/GP5+PCR was 79.79%,and the prevalence of HPV types16 and 18 was 40.40%and 47.47%,respectively.PCR demonstrated the presence of HPV,and direct sequencing confirmed the HPV genotypes.All HPVpositive PCR products were checked by DNA sequence analysis using DNAman and compared with the known HPV sequences listed in the basic Local Alignment Search tool database to evaluate the HPV types.this analysis confirmed the presence of HPV types 16 and18.CONCLUSION:DNA of high-risk HPV types 16 and 18is present in esophageal tumors,implicating HPV as a possible etiologic factor for esophageal squamous cell carcinoma.     

Electrocatalytic oxidation of hydrazine on a carbon paste electrode modified by hybrid hexacyanoferrates of copper and cobalt films

A stable electroactive thin film of hybrid copper-cobalt hexacyanoferrate (CuCoHCF) was electrodeposited on a carbon paste electrode by cyclic voltammetry. The modified electrode exhibits good catalytic activity for the oxidation of hydrazine at a reduced overpotential with good sensitivity in the wide concentration range 0.1–12 mM hydrazine. A Tafel plot, derived from voltammograms, indicated a one-electron charge transfer process to be the rate-limiting step and the overall number of electrons involved in the catalytic oxidation of hydrazine was found to be 4. The CuCoHCF modified-electrode exhibited stable electrochemical responses in a wide pH range 2–10 and showed excellent electrocatalytic activity toward the oxidation of hydrazine in 0.1 M phosphate buffer, pH 7. The diffusion coefficient of hydrazine and rate constant for the catalytic reaction were also evaluated. Finally the proposed modified electrode exhibited several attractive features, such as simple preparation, fast response, good stability and repeatability and could be applied as an amperometric sensor for hydrazine.     

Sera of Peruvians with fever of unknown origins include viral nucleic acids from non-vertebrate hosts

Serum samples collected from 88 Peruvians with unexplained fever were analyzed for viral sequences using metagenomics. Nucleic acids of anelloviruses, pegivirus A (GBV-C), HIV, Dengue virus, and Oropouche virus were detected. We also characterized from two sera the RNA genomes of new species of partitivirus and dicistrovirus belonging to viral families known to infect fungi or arthropod, respectively. Genomic DNA of a putative fungal cellular host could be PCR amplified from the partitivirus-containing serum sample. The detection in human serum of nucleic acids from viral families not known to infect vertebrates may indicate contamination during sample collection and aliquoting or human infection by their presumed cellular host, here a fungus. The role, if any, of the non-vertebrate infecting viruses detected in serum in inducing fever is unknown.