Gate-controlled spin-valley-layer locking in bilayer transition-metal dichalcogenides.

The interplay between various internal degrees of freedom of electrons is of fundamental importance for designing high performance electronic devices. A particular instance of this interplay can be observed in bilayer TMDs due to the combined effect of spin-orbit and interlayer couplings. We study the transport of spin, valley and layer pseudospin, generally, through a magnetoelectric barrier in AB-stacked bilayer TMDs and demonstrate an electrically controllable platform for multifunctional and ultra-high-speed logic devices. Perfect spin and valley polarizations as well as good layer localization of electrons occur in a rather large range of Fermi energies for moderate electric and magnetic fields. Any number of these polarizations can be inverted by adjusting the two potential gates on the two layers. Furthermore, the conditions for the excellent polarizations are determined for the spin, valley and layer degrees of freedom, in terms of the adjustable system parameters. We discuss the individual electric and magnetic barriers and show that the single electric barrier acts as a bipolar pseudospin semiconductor with opposite polarizations for the conduction and valence bands. The results of this study pave the way for multifunctional pseudospintronic applications based on 2D materials.

Spin and valley dependent electronic transport in molybdenum disulfide considering up to the second order k-dependent terms: a more exact solution.

Previous studies of electronic transport in molybdenum disulfide (MoS2) are restricted to the first order approximation of the Hamiltonian. In this paper, to obtain more exact results, we firstly present an analytical solution for the Hamiltonian of MoS2 when terms up to the second order (quadratic k-dependent) of the Hamiltonian are taken into account. Our analytical solution is easily applicable to study the transport properties of any single and multi-junctions of MoS2. Then, we propose a device composed of two ferromagnetic barriers with anti-parallel exchange fields and we show that this device has interesting properties such as spin and valley filtering with perfect spin and valley polarizations. Using this device, we can easily switch both spin and valley polarizations to their opposite polarizations only by using electric voltage, which is of fundamental importance in quantum computation and the next generation of logic devices.

Strain engineering of valley polarized currents in topological crystalline insulators.

Although the existence of four valley degrees of freedom in the (0 0 1) surface of IV-VI semiconductor topological crystalline insulators (TCIs) provides the opportunity to multiply the valleytronic functionality, it makes the generation of highly polarized valley currents less plausible. We investigate quantum adiabatic valley pumping in (0 0 1) surface of these TCIs and show that applying shear strains and exchange field gives the possibility of control and manipulation of the valley resolved currents with high polarizations. Interchange of polarizations, simply by turning the tensile strain into compressive mode and vice versa, highlights the potential application for valleytronic switching process. Furthermore, since the surface states are robust against disorders, we can increase the lengths of driving regions and pump significantly larger currents without breaking the coherency of the quantum transport regime.

Generation of large spin and valley currents in a quantum pump based on molybdenum disulfide.

Generation of large currents, versatile functionality, and simple structures are of fundamental importance in the development of adiabatic quantum pump devices with nanoscale dimensions. In the present study, we propose an adiabatic quantum pump with a simple structure based on molybdenum disulfide, MoS2, to generate large spin and valley resolved currents. We show that pure and fully polarized spin and valley currents can be easily generated by employing two potential gates and using an exchange magnetic field. Unlike graphene and silicene, in order to induce a valley resolved current in MoS2, one does not need to induce strain and apply an electric field. The spin and valley resolved currents are completely coupled together, so that the spin up (down) current is exactly equal to the valley K(K') current. Hence, we can detect the valley resolved current by utilizing more straightforward and simple methods used for the detection of spin resolved currents. The other prominent feature of this proposed pump is its large current, which is two and three orders of magnitude larger than the maximum current of similar pump structures based on silicene and graphene, respectively. The results of this study are promising for the fabrication of quantum pumps with large spin and valley resolved currents, which opens up the possibility of further development of spintronics and valleytronics in 2D nanostructures.

Controllable quantum valley pumping with high current in a silicene junction.

We propose an efficient scheme for the generation and control of both pure and fully polarized valley currents in a silicene-based junction, using adiabatic quantum pumping. The pure and fully polarized valley currents are induced using ferromagnetic proximity and the application of a perpendicular electric field. We show that the valley polarized current can easily be switched from valley K to valley [Formula: see text] and vice versa, simply by reversing the direction of the electric field. Thus, the valley current is controllable electrically. Compared to the methods proposed for generation of valley current by quantum pumping in graphene, which are based on inducing strain on its sheet, our method is very simple and can be easily utilized in practical applications. Also, we show that the magnitude of pumped current in a silicene-based junction is roughly one order of magnitude greater than that of graphene. In addition to valley-related currents, our pump scheme can be used on its own to generate pure and fully polarized spin currents. A comparison between weak and strong adiabatic regimes is given, and the effects of some structural parameters that can significantly affect the pumping currents and polarizations are discussed.

Comparative characteristics of mesenchymal stem cells derived from reamer-irrigator-aspirator, iliac crest bone marrow, and adipose tissue.

Mesenchymal stem cells (MSCs) have been considered promising tools for new clinical concepts in supporting cellular therapy and regenerative medicine. More recently, Ream/Irrigator/Aspirator (RIA) was introduced as a source of MSCs. In this study we compared MSCs derived from three different sources (iliac crest bone marrow (ICBM), adipose tissue (AT), and (RIA)) regarding the morphology, the success rate of isolating MSCs, colony frequency, expansion potential, osteogenic and chondrogenic differentiation capacity. MSCs were isolated from three different sources and flow cytometric analyses were performed for cell characterization. Colony-forming unit-fibroblast (CFU-F) assay and population doubling time (PDT) were evaluated for MSCs derived from three different sources and differentiation potential of RIA, ICBM-, and AT-MSCs were determined by staining. Additionally, gene expression profiles for tissue specific markers corresponding to osteogenesis and chondrogenesis were analyzed using real time polymerase chain reaction (RT-PCR). Cultured with the appropriate condition, osteogenic and chondrogenic differentiation could be confirmed in all MSC preparations. Flow cytometry analysis indicated that RIA- and AT-derived MSCs have more homogenous populations than ICBM-MSCs. A comparison of the colonogenic ability in different tissues by CFU-F assay after 10 days showed that more colonies are formed from RIA-MSCs than from ICBM-MSCs, and AT-MSCs. AT-MSCs, were dispersed with no obvious colonies. The RIA-MSCs underwent osteogenesis and chondrogenesis at a faster rate than ICBM and AT-MSCs. Direct comparisons of RIA- to ICBM- and AT-MSCs have shown the RIA-MSCs have higher differentiation toward osteoblast and chondrocytes compared to other sources of MSCs. Hence, RIA-MSCs may be recommended as a more suitable source for treating orthopedic disorders.

Quality of life of Iranian beta-thalassaemia major patients living on the southern coast of the Caspian Sea.

In the present study, the aim was to explore the quality of life of thalassaemia major (TM) patients according to age, sex, school performance, severity and complications of the disease. A cross-sectional descriptive study was conducted. Quality of life was evaluated by 4 questionnaires; demographic characteristics, the short form 36 health survey (SF-36), Persian version of symptoms checklist-90-revised (SCL-90-R) and life satisfaction index (LSI). 687 (41.08%) of the eligible patients with TM completed the questionnaires. With the SF-36 questionnaire, 329 (47.9%) participants had an excellent level of physical functioning. With the SCL-90-R questionnaire, 446 (64.9%) participants had a global severity index of > 0.7, considered psychiatric patients, 141 (20.5%) patients had GSI between 0.4 and 0.7, considered suspected psychiatric patients and 100 (14.6%) participants had GSI of < 0.4, considered non-psychiatric patients. The mean score of LSI questionnaire was 20.50 (SD 5.95), range 2-37. Beta-TM patients are at risk of psychiatric symptoms and need appropriate psychiatric counselling.

Quality of life of Iranian beta-thalassaemia major patients living on the southern coast of the Caspian Sea

In the present study, the aim was to explore the quality of life of thalassaemia major [TM] patients according to age, sex, school performance, severity and complications of the disease. A cross-sectional descriptive study was conducted. Quality of life was evaluated by 4 questionnaires; demographic characteristics, the short form 36 health survey [SF-36], Persian version of symptoms checklist-90-revised [SCL-90-R] and life satisfaction index [LSI]. 687 [41.08%] of the eligible patients with TM completed the questionnaires. With the SF-36 questionnaire, 329 [47.9%] participants had an excellent level of physical functioning. With the SCL-90-R questionnaire, 446 [64.9%] participants had a global severity index of > 0.7, considered psychiatric patients, 141 [20.5%] patients had GSI between 0.4 and 0.7, considered suspected psychiatric patients and 100 [14.6%] participants had GSI of < 0.4, considered non-psychiatric patients. The mean score of LSI questionnaire was 20.50 [SD 5.95], range 2-37. Beta-TM patients are at risk of psychiatric symptoms and need appropriate psychiatric counseling

Knowledge, attitudes and practices towards HIV/AIDS among Iranian prisoners in Mazandaran province in the south-coast area of the Caspian Sea.

HIV infection in the Islamic Republic of Iran is concentrated primarily among intravenous drug users. This study investigated the knowledge, attitudes and practices towards HIV/AIDS prevention of a random sample of prisoners in 5 prisons in Mazandaran province. Of 1760 individuals aged 18-65 years old completing the questionnaire, the mean age was 30.1 (SD 8.1) years (range 18 to 59 years); 95.8% were male. Respondents had an average to fairly good knowledge about HIV/AIDS, with the percentages answering correctly ranging from 11.9% to 85.9%. However many had the misconception that "HIV/AIDS does not influence Iran" and "I will not be infected with HIV/AIDS under any conditions" and 63.6% agreed that lack of religious and moral commitment could spread AIDS infection. HIV/AIDS prevention efforts are needed for prisoners in Mazandaran province.

Electrochemical Analysis of Some Toxic Metals by Ion-Selective Electrodes.

An overview of potentiometric sensors that are capable of detecting toxic heavy metal ions in environmental samples is presented and discussed. Notwithstanding the tremendous work performed so far, it is obvious that still several limitations do exist in terms of selectivity, limits of detection, dynamic ranges, applicability to specific problems, and reversibility. A survey on important advances in potentiometric sensors with regard to high selectivity, lower detection limit, fast response time, and on-line environmental analysis is presented in this review article. [Supplemental materials are available for this article. Go to the publisher's online edition of Critical Reviews in Analytical Chemistry to view the free supplemental file.].

Knowledge, attitudes and practices towards HIV/ AIDS among Iranian prisoners in Mazandaran province in the south-coast area of the Caspian Sea

HIV infection in the Islamic Republic of Iran is concentrated primarily among intravenous drug users. This study investigated the knowledge, attitudes and practices towards HIV/AIDS prevention of a random sample of prisoners in 5 prisons in Mazandaran province. Of 1760 individuals aged 18-65 years old completing the questionnaire, the mean age was 30.1 [SD 8.1] years [range 18 to 59 years]; 95.8% were male. Respondents had an average to fairly good knowledge about HIV/AIDS, with the percentages answering correctly ranging from 11.9%to 85.9%. However many had the misconception that [HIV/AIDS does not influence Iran] and [I will not be infected with HIV/AIDS under any conditions] and 63.6% agreed that lack of religious and moral commitment could spread AIDS infection. HIV/AIDS prevention efforts are needed for prisoners in Mazandaran province