Manipulation of Magnetization Switching by Ultrafast Spin-Polarized Hot-Electron Transport in Synthetic Antiferromagnet

Uncovering the physical mechanisms that govern ultrafast charge and spin dynamics is becoming indispensable both at the fundamental level and to develop future spin-based electronics. Recently it has been shown that femtosecond pulsed-laser excitation of magnetic thin films produces intense and ultrafast spin-polarized hot electrons, thus attracting a lot of attention. While spin-polarized hot electrons are known to play a pivotal role in the ultrafast laser-induced demagnetization, their effect on magnetization switching remains an open issue. This study uncovers the effect of spin-polarized hot electrons generated by laser excitation on magnetization switching in a Co/Pt based perpendicular magnetic anisotropy-based synthetic antiferromagnet (p-SAF) using the time-resolved magneto-optical Kerr effect. It has been found that, at low pump fluence, the equivalent magnetic field generated by the hot-electron spin current plays a dominant role in assisting the magnetization switching of the lower layer in the antiferromagnetic configuration, while the strong thermal stability of the Ruderman Kittel Kasuya Yosida exchange interaction inhibits the further weakening of the switching field at high pump fluence. This study provides a viable way to control the magnetization switching of the antiferromagnetically exchange-coupled systems for spintronic applications with ultrafast control of the information operation

Changes in sexual behaviors among HIV-infected individuals after their HIV diagnosis in a rural prefecture of Eastern China.

OBJECTIVE: To describe changes in sexual behaviors among HIV-infected individuals after their HIV diagnosis. METHODS: All HIV-infected individuals diagnosed by the end of 2009 in Taizhou Prefecture were invited to participate in this 12-month prospective study. Assessments including the total number and types of sexual contacts, and condom use details for up to their most familiar eight sexual contacts were collected both at enrollment and 12-month follow-up. RESULTS: 262 HIV-infected individuals were eligible for analysis. The total number of sexual contacts reported by participants was 4,017, 1,496 and 356 during the 12- month period prior to HIV diagnosis (T1), the 12-month period prior to the baseline survey (T2), and the 12-month follow-up period (T3), respectively. The difference in the number of sexual contacts between T2 and T1 was -5 in median (IQR -1, -14), and the difference between T3 and T2 was 0 in median (IQR: 0, -6). A larger proportion of spousal or long-term heterosexual contact was reported from T1(27.7%) to T2(42.5%) to T3(76.1%), whereas a smaller proportion of commercial heterosexual contacts was reported from T1 (48.6%) to T2 (33.2%) to T3 (7.0%) as well as a smaller proportion of non-commercial casual homosexual contacts was reported from T2 (8.4%) to T3 (3.8%).The proportion of consistent condom use increased significantly from T1 (9.3%) to T2 (35.3%) to T3 (91.5%). CONCLUSION: Sexual behaviors did not change in a uniform manner for the participants in our study. Sexual behaviors and sexual networks vis-à-vis HIV diagnosis and follow-up were associated with the participant's characteristics and HIV infection and treatment status. The overall lesson is that individuals who are unaware of their HIV infection are the main drivers of secondary transmission. Early identification of HIV infection and access to antiretroviral therapy (ART) are both key strategies to the control and prevention

Promising optoelectronic properties and potential infrared photodetection applications of two-dimensional monolayer PdTeI2

Searching for novel two-dimensional (2D) materials with excellent properties is of great importance for the design of next generation nano-devices. Based on first-principles calculations, we propose an unexplored 2D monolayer PdTeI2 material, which can be prepared from its bulk crystal by exfoliation method. Our calculations show that monolayer PdTeI2 has excellent dynamical and thermal stability. The appropriate bandgap of 0.82 eV endows monolayer PdTeI2 with superior optical absorption capacity in the infrared and visible regions. Remarkably, the in-plane electron mobility of monolayer PdTeI2 is as high as 104cm2v-1s-1, which is much larger than those of most previously reported 2D materials. Based on the combination of density functional theory and non-equilibrium Green’s function formalism, a large photocurrent of 40 a02/photon for photon energy of 1.0 eV is obtained under a small bias voltage in PdTeI2-based two-electrode optoelectronic devices, indicating the outstanding photoresponse characteristic of monolayer PdTeI2 in the infrared region. The large photocurrent, along with the high electron mobility and strong optical absorption make monolayer PdTeI2 a candidate material for future applications in novel optoelectronics and microelectronic devices, such as infrared photodetectors

Dual-modified cationic liposomes loaded with paclitaxel and survivin siRNA for targeted imaging and therapy of cancer stem cells in brain glioma

Development of safe, efficient nanocomplex for targeted imaging and therapy of cancer stem cells in brain glioma has become a great challenge. Herein, a low-density lipoprotein receptor-related protein and a RNA aptamer bound CD133 were used as dual-targeting ligands to prepare dual-modified cationic liposomes (DP-CLPs) loaded with survivin siRNA and paclitaxel (DP-CLPs–PTX–siRNA) for actively targeting imaging and treating CD133+ glioma stem cells after passing through the blood–brain barrier. After being administrated with DP-CLPs–PTX–siRNA nanocomplex, DP-CLPs showed a persistent target ability to bind glioma cells and brain microvascular endothelial cells (BCECs) and to deliver drugs (PTX/siRNA) to CD133+ glioma stem cells. Prepared DP-CLPs–PTX–siRNA nanocomplex showed very low cytotoxicity to BCECs, but induced selectively apoptosis of CD133+ glioma stem cells, and improved CD133+ glioma stem cells' differentiation into non-stem-cell lineages, also markedly inhibited tumorigenesis, induced CD133+ glioma cell apoptosis in intracranial glioma tumor-bearing nude mice and improved survival rates. In conclusion, prepared DP-CLPs–PTX–siRNA nanocomplex selectively induced CD133+ glioma stem cell apoptosis in vitro and in vivo exhibits great potential for targeted imaging and therapy of brain glioma stem cells

A schematic flow chart of the study sample.

<p>A schematic flow chart of the study sample.</p

Sexual relationship and condom use of HIV individuals with their most familiar sexual contacts in the 12 months period prior to HIV diagnosis (T1), the baseline survey (T2) and the one-year follow-up survey (T3), respectively, in Taizhou prefecture, 2009–2010.

<p><b>Note:</b> n refers to the total number of sexual contacts reported;</p>†<p>Chi-square test or Fisher’s exact test compare the proportion of types of sexual contacts or condom use of HIV individuals between T2 and T1;</p>‡<p>Chi-square test or Fisher’s exact test compare the proportion of types of sexual contacts or condom use of HIV individuals between T3 and T2.</p