Enhanced spin accumulation at room temperature in graphene spin valves with amorphous carbon interfacial layers

We demonstrate a large enhancement of the spin accumulation in monolayer graphene following electron-beam induced deposition of an amorphous carbon layer at the ferromagnet-graphene interface. The enhancement is 10^4-fold when graphene is deposited onto poly(methyl metacrylate) (PMMA) and exposed with sufficient electron-beam dose to cross-link the PMMA, and 10^3-fold when graphene is deposited directly onto SiO2 and exposed with identical dose. We attribute the difference to a more efficient carbon deposition in the former case due to an increase in the presence of compounds containing carbon, which are released by the PMMA. The amorphous carbon interface can sustain very large current densities without degrading, which leads to very large spin accumulations exceeding 500 microeVs at room temperature

A Case of Ciliate Protozoa Colpoda Spp. (Ciliata: Colpodidae) Detected In Human Urine

In the urine of a patient with chronic prostatitis, renal microlithiasis and acute cystitis we found the ciliate protozoa Colpoda spp., both in vegetative and cystic form. The entry point was most likely the urinary tract. Keeping in mind that only four more cases of Colpoda spp. existent in human urine have already been described, and that in the case of our patient the ciliate was present at repeated examinations of his urine, we presumed that it is not only a spurious infection of the urogenital tract. It still remains to be analyzed whether this ciliate belongs to a species of Colpoda adapted to parasitism in homeothermae and whether it can be pathogenic for humans

Fingerprints of Inelastic Transport at the Surface of the Topological Insulator Bi2Se3: Role of Electron-Phonon Coupling

We report on electric-field and temperature dependent transport measurements in exfoliated thin crystals of Bi$_{2}$Se$_{3}$ topological insulator. At low temperatures ($< 50$ K) and when the chemical potential lies inside the bulk gap, the crystal resistivity is strongly temperature dependent, reflecting inelastic scattering due to the thermal activation of optical phonons. A linear increase of the current with voltage is obtained up to a threshold value at which current saturation takes place. We show that the activated behavior, the voltage threshold and the saturation current can all be quantitatively explained by considering a single optical phonon mode with energy $\hbar \Omega \approx 8$ meV. This phonon mode strongly interacts with the surface states of the material and represents the dominant source of scattering at the surface at high electric fields.Comment: Supplementary Material at: http://journals.aps.org/prl/supplemental/10.1103/PhysRevLett.112.086601/TIPhonon_SM.pd

Toxoplasmic Infection in Pregnant Women from Cluj County and Neighbouring Area

Toxoplasmosis is an antropozoonosis very frequent in population as a benign usually asymptomatic disease. The problems are raised by the congenital form of this disease that may occur if the women acquire the parasite during pregnancy leading to congenital toxoplasmosis. In order to prevent congenital toxoplasmosis many countries have screening programs design to diagnose the acute infection during fertile age of female population. Our prospective serologic study over a selected group of 510 pregnant women in Cluj county area showed a 39 % prevalence of toxoplasmic infection among women of fertile age, with a predominance of acute toxoplasmic infection during first trimester of pregnancy (66.66%), representing the predominant cause of abortion in our study group. Annual infection risk for female population aged 20-33 years old is K = 0.67% in our geographic area. A 4 % of cases had IgM persistence for more than 1-year period, and another 7% demonstrate positive IgM along with positive IgG raising the possibility of persistency to 11% of cases. We find out that half of women address laboratory by their own initiative and we calculate that medium age of pregnant women with toxoplasmic immunity (positive IgG) was 28 years old

Hot-Carrier Seebeck Effect: Diffusion and Remote Detection of Hot Carriers in Graphene

We investigate hot carrier propagation across graphene using an electrical nonlocal injection/detection method. The device consists of a monolayer graphene flake contacted by multiple metal leads. Using two remote leads for electrical heating, we generate a carrier temperature gradient that results in a measurable thermoelectric voltage VNL across the remaining (detector) leads. Due to the nonlocal character of the measurement, VNL is exclusively due to the Seebeck effect. Remarkably, a departure from the ordinary relationship between Joule power P and VNL, VNL ~ P, becomes readily apparent at low temperatures, representing a fingerprint of hot-carrier dominated thermoelectricity. By studying VNL as a function of bias, we directly determine the carrier temperature and the characteristic cooling length for hot-carrier propagation, which are key parameters for a variety of new applications that rely on hot-carrier transport

Detection and Characterization of Solid Pancreatic Lesions (Contrast-Enhancement, Elastography, EUS-Guided Fine Needle Aspiration)

AbstractFor detection of small pancreatic tumors and characterization of focal pancreatic masses, endoscopic ultrasound (EUS) is the most sensitive of the imaging procedures currently available. Differential diagnosis between benign and malignant focal pancreatic masses based on the EUS appearance is difficult and frequently requires EUS-guided fine needle aspiration (EUS-FNA) for confirmation of malignancy. New techniques improve the sensitivity, specificity, and accuracy of the differential diagnosis, as well as diagnosis of small pancreatic tumors (less than 2 cm diameter) by using real-time elastography or contrast-enhanced EUS. Nevertheless, EUS-FNA is still required for the final diagnosis in most of the cases, which allows an evidence-based management with referral to either curative surgery or palliative chemoradiotherapy. This article is part of an expert video encyclopedia