Defect-Engineered Atomically Thin MoS2 Homogeneous Electronics for Logic Inverters

Ultrathin molybdenum disulfide (MoS₂ ) presents ideal properties for building next-generation atomically thin circuitry. However, it is difficult to construct logic units of MoS₂ monolayer using traditional silicon-based doping schemes, such as atomic substitution and ion implantation, as they cause lattice disruption and doping instability. An accurate and feasible electronic structure modulation strategy from defect engineering is proposed to construct homogeneous electronics for MoS₂ monolayer logic inverters. By utilizing the energy-matched electron induction of the solution process, numerous pure and lattice-stable monosulfur vacancies (V_monos ) are introduced to modulate the electronic structure of monolayer MoS₂ via a shallow trapping effect. The resulting modulation effectively reduces the electronic concentration of MoS₂ and improves the work function by 100 meV. Under modulation of V_monos , an atomically thin homogenous monolayer MoS₂ logic inverter with a voltage gain of 4 is successfully constructed. A brand-new and practical design route of defect modulation for 2D-based circuit development is provided.

A-Site Management for Highly Crystalline Perovskites

An in-depth understanding and effective suppression of nonradiative recombination pathways in perovskites are crucial to their crystallization process, in which supersaturation discrepancies at different time scales between CH₃ NH₃ I (MAI, methylammonium iodide) and PbI₂ remain a key issue. Here, an A-site management strategy via the introduction of an A-site placeholder cation, NH₄ ⁺ , to offset the deficient MA⁺ precipitation by occupying the cavity of Pb-I framework, is proposed. The temporarily remaining NH₄ ⁺ is substituted by subsequently precipitated MA⁺ . The temperature-dependent crystallization process with the generation and consumption of a transient phase is sufficiently demonstrated by the dynamic changes in crystal structure characteristic peaks through in situ grazing-incidence X-ray diffraction and the surface potential difference evolution through temperature-dependent Kelvin probe force microscopy. A highly crystalline perovskite is consequently acquired, indicated by the enlarged grain size, lowered nonradiative defect density, prolonged carrier lifetime, and fluorescence lifetime imaging. Most importantly, it is identified that the A-site I_MA defect is responsible for such crystal quality optimization based on theoretical calculations, transient absorption, and deep-level transient spectroscopy. Furthermore, the universality of the proposed A-site management strategy is demonstrated with other mixed-cation perovskite systems, indicating that this methodology successfully provides guidance for synthesis route design of highly crystalline perovskites.

[Epidemiological analysis of the deaths with antiretroviral treatment among adult HIV/AIDS patients in Liangshan Yi Autonomous Prefecture from 2005 to 2015]

Objective: To analyze the deaths with antiretroviral treatment among adult HIV/AIDS patients in Liangshan Yi Autonomous Prefecture from 2005 to 2015, in order to understand the epidemiological characteristics and to further reduce the mortality rate in Liangshan Prefecture. Methods: The relevant information was collected through the Management Database of Antiretroviral Treatment from the National AIDS Comprehensive Prevention Information System. Results: From 2005 to 2015, a total of 14 219 adult HIV/AIDS patients received antiretroviral treatment and 1 425 death cases were reported during the treatment. The cause of death was mainly AIDS-related diseases (58.9%), and the cumulative mortality rate was 10.02%. Gender, age, the way of infection, duration of antiretroviral therapy, clinical stage when received antiretroviral therapy, and CD(4)(+) T lymphocyte levels were factors for the mortality rate (P<0.001). The mortality increased with older age, higher initiation clinical stage and lower level of CD(4)(+) T lymphocyte. Among the death cases, 82.6% were male, 1 182 (82.9%) were married or cohabited, most aged between 30-39 years old (48.6%). At the initial point of receiving antiretroviral therapy, 49.7% of the cases with CD(4)(+)T lymphocytes levels< 200/μl, 61.2% of the deaths cases were>1 000 copies/ml during the last viral load test, and 16.2% of deaths were ≥500/μl in the last CD(4)(+)T lymphocyte test; 44.5% of deaths were received antiretroviral treatment within one year. Conclusion: Early and timely antiretroviral therapy should be carried out. It is necessary to strengthen the propaganda of antiretroviral therapy and to improve the management quality of follow-up information of antiretroviral therapy case files, and to improve the medication compliance of patients.

[Clinicopathologic features of secretory breast carcinoma]

Objective: Investigate the clinicopathological features for secretory carcinoma of breast (SCB). Methods: The clinical data of 3 SCB cases were collected, immunohistochemical staining was performed by the streptavidin-peroxidase (SP) method to test the expression of the antibodies: ER, PR, HER-2, Ki-67, S100, CK5/6, p63, SMA, calponin, GCDFP-15, and EGFR. Fluorescence in situ hybridization (FISH) was used to detect the ETV6-NTRK3 gene fusion. Results: ER was focal weakly positive in case 1 and case 2 (about 5%) , and negative in case 3. PR was focal weakly positive in case 1 (about 5%) and completely negative in case 2 and case 3. Three cases showed that HER-2, SMA, calponin, GCDFP-15 were negative, while S100, CK5/6, EGFR were diffuse strongly positive. The proliferation index was nearly 15% in case 1 and case 2, and 10% in case 3. p63 was negative in mostly tumor cells of case 1, and focal positive expression in the nucleus and cytoplasm. In case 2, p63 was completely negative. However, p63 was observed positive in the cytoplasm as well as some secretory material in case 3. ETV6-NTRK3 gene fusion detection by FISH was positive in all cases. Conclusions: SCB is a rare low grade triple-negative breast cancer with the unique pathomorphologic features, while its recurrent t (12; 15) (p13; q25) translocation resulting in ETV6 -NTRK3 gene fusion. It has the indolent clinical behavior and good prognosis.

Graphene-Based Mixed-Dimensional van der Waals Heterostructures for Advanced Optoelectronics

Although the library of 2D atomic crystals has greatly expanded over the past years, research into graphene is still one of the focuses for both academia and business communities. Due to its unique electronic structure, graphene offers a powerful platform for exploration of novel 2D physics, and has significantly impacted a wide range of fields including energy, electronics, and photonics. Moreover, the versatility of combining graphene with other functional components provides a powerful strategy to design artificial van der Waals (vdWs) heterostructures. Aside from the stacked 2D-2D vdWs heterostructure, in a broad sense graphene can hybridize with other non-2D materials through vdWs interactions. Such mixed-dimensional vdWs (MDWs) structures allow considerable freedom in material selection and help to harness the synergistic advantage of different dimensionalities, which may compensate for graphene's intrinsic shortcomings. A succinct overview of representative advances in graphene-based MDWs heterostructures is presented, ranging from assembly strategies to applications in optoelectronics. The scientific merit and application advantages of these hybrid structures are particularly emphasized. Moreover, considering possible breakthroughs in new physics and application potential on an industrial scale, the challenges and future prospects in this active research field are highlighted.

Strain-Engineered van der Waals Interfaces of Mixed-Dimensional Heterostructure Arrays

van der Waals (vdWs) heterostructures have provided a platform for nanoscale material integrations and enabled promise for use in optoelectronic devices. Because of the ultrastrength of two-dimensional materials, strain engineering is considered as an effective way to tune their band structures and further tailor the interface performance of vdWs heterostructures. However, the less-constrained vdWs interfaces make the traditional strain technique via lattice-mismatched growth infeasible. Here, we report a strategy to construct mixed-dimensional heterostructure arrays with periodically strain-engineered vdWs interfaces utilizing one-dimensional semiconductor-induced nanoindentation. Using monolayer MoS₂ (1L-MoS₂)/ZnO heterostructure arrays as a model system, we demonstrate inhomogeneous built-in strain gradient at the heterointerfaces ranging from 0 to 0.6% tensile. Through systematic optical characterization of the hybrid structures, we verify that strain can improve the interfacial charge transfer efficiency. Consequently, we observe that the photoluminescence (PL) emission of 1L-MoS₂ at strained interfaces is dramatically quenched more than 50% with respect to that at unstrained interfaces. Furthermore, we confirm that the strain-optimized interfacial carrier behavior is attributed to the reduction of interfacial barrier height, which originated from the strain-dependent Fermi level of 1L-MoS₂. These results demonstrate that strain provides another degree of freedom in tuning the vdWs interface performance and our method developed here should enable flexibility in achieving more sophisticated vdWs integration via strain engineering.

Toward the Application of High Frequency Electromagnetic Wave Absorption by Carbon Nanostructures

With the booming development of electronic information technology, the problems caused by electromagnetic (EMs) waves have gradually become serious, and EM wave absorption materials are playing an essential role in daily life. Carbon nanostructures stand out for their unique structures and properties compared with the other absorption materials. Graphene, carbon nanotubes, and other special carbon nanostructures have become especially significant as EM wave absorption materials in the high-frequency range. Moreover, various nanocomposites based on carbon nanostructures and other lossy materials can be modified as high-performance absorption materials. Here, the EM wave absorption theories of carbon nanostructures are introduced and recent advances of carbon nanostructures for high-frequency EM wave absorption are summarized. Meanwhile, the shortcomings, challenges, and prospects of carbon nanostructures for high-frequency EM wave absorption are presented. Carbon nanostructures are typical EM wave absorption materials being lightweight and having broadband properties. Carbon nanostructures and related nanocomposites represent the developing orientation of high-performance EM wave absorption materials.

[Data analysis on HIV/AIDS sentinel surveillance programs targeting community population in Liangshan Yi Autonomous Prefecture, 2010-2015]

Objective: To investigate the epidemiologic and behavioral characteristics of HIV among community population in Liangshan prefecture. Methods: We collected social demographic, behavioral and serological information by means of the monitoring questionnaire and serological tests. Data was analyzed by using the chi-square test and logistic regression. Results: From April to June of 2010 to 2015, 14 092 cases of community population were selected as the study objects, with 267 cases diagnosed as HIV positive patients. The HIV positive rates were 3.24%, 3.07%, 1.17%, 1.38%,1.42% and 1.25%, respectively. We observed that when community population having the following characteristics as: living in Butuo country (OR=3.83), being males (OR=1.77), being Yi nationality (OR=4.40) being widowed (OR=28.57), with history of drug abuse (OR=3.71) or injecting drug use (PWID) (OR=4.92), or history of needle sharing among PWID (OR=8.53), were under higher risks for HIV infection. With histories as: having had secondary or above levels of schooling (OR=0.59), having protected sex with regular partners (OR=0.21) and with non-regular partners (OR=0.46), they seemed to be somehow protected for getting HIV infection. Conclusion: The positive HIV rates of HIV among community population in Dechang, Ningnan and Butuo varied from 0.10% to 8.77% while the HIV transmission among general population remained challenging.

Self-Healing Originated van der Waals Homojunctions with Strong Interlayer Coupling for High-Performance Photodiodes

The dangling-bond-free surfaces of van der Waals (vdW) materials make it possible to build ultrathin junctions. Fundamentally, the interfacial phenomena and related optoelectronic properties of vdW junctions are modulated by the interlayer coupling effect. However, the weak interlayer coupling of vdW heterostructures limits the interlayer charge transfer efficiency, resulting in low photoresponsivity. Here, a bilayer MoS₂ homogeneous junction is constructed by stacking the as-grown onto the self-healed monolayer MoS₂. The homojunction barrier of ∼165 meV is obtained by the electronic structure modulation of defect self-healing. This homojunction reveals the stronger interlayer coupling effect in comparison with vdW heterostructures. This ultrastrong interlayer coupling effect is experimentally verified by Raman spectra and angle-resolved photoemission spectroscopy. The ultrafast interlayer charge transfer takes place within ∼447 fs, which is faster than those of most vdW heterostructures. Furthermore, the homojunction photodiode manifests outstanding rectifying behavior with an ideal factor of ∼1.6, perfect air stability over 12 months, and high responsivity of ∼54.6 mA/W. Moreover, the interlayer exciton peak of ∼1.66 eV is found in vdW homojunctions. This work offers an uncommon vdW junction with strong interlayer coupling and perfects the relevance of interlayer coupling and interlayer charge transfer.

Detection and analysis of laser driven proton beams by calibrated Gafchromic HD-V2 and MD-V3 radiochromic films

The radiochromic film (RCF) is a high-dose, high-dynamic range dosimetry detection medium. A stack of RCFs can be used to detect both spatial and energetic distribution of laser driven ion beams with a large divergence angle and continuous energy spectrum. Two types of RCFs (HD-V2 and MD-V3, from Radiation Products Design, Inc.) have been calibrated using MeV energy protons and carbon ions produced by using a 2 × 6 MV tandem electrostatic accelerator. The proportional relationship is obtained between the optical density and the irradiation dose. For protons, the responses are consistent at all energies with a variation of about 15%. For carbon ions, the responses are energy related, which should be noted for heavy ion detection. Based on the calibration, the broad energy spectrum and charge distribution of laser accelerated proton beam with energy from 3 to 8 MeV and pC charge were detected and reconstructed at the Compact LAser Plasma Accelerator at Peking University.

Graphdiyne Nanowall for Enhanced Photoelectrochemical Performance of Si Heterojunction Photoanode

Graphdiyne (GDY), a new member of 2D carbon material family, was introduced into a Si heterojunction (SiHJ)-based photoelectrochemical water splitting cell. With assistance of magnetron-sputtered NiO_x, the plateau photocurrent density of SiHJ/GDY/NiO _x-10 nm with optimized NiO _x film thickness was twice higher than that of SiHJ/NiO _x-10 nm, demonstrating the catalytic function of GDY itself as well as the synergistic effect between GDY and NiO _x. The results verified that GDY is a promising photoelectrode material candidate to realize highly efficient PEC performance, and pave a novel pathway to further improve Si-based PEC system.

Laser Acceleration of Highly Energetic Carbon Ions Using a Double-Layer Target Composed of Slightly Underdense Plasma and Ultrathin Foil

We report the experimental generation of highly energetic carbon ions up to 48 MeV per nucleon by shooting double-layer targets composed of well-controlled slightly underdense plasma and ultrathin foils with ultraintense femtosecond laser pulses. Particle-in-cell simulations reveal that carbon ions are ejected from the ultrathin foils due to radiation pressure and then accelerated in an enhanced sheath field established by the superponderomotive electron flow. Such a cascaded acceleration is especially suited for heavy ion acceleration with femtosecond laser pulses. The breakthrough of heavy ion energy up to many tens of MeV/u at a high repetition rate would be able to trigger significant advances in nuclear physics, high energy density physics, and medical physics.

All-Inorganic Perovskite Quantum Dot-Monolayer MoS2 Mixed-Dimensional van der Waals Heterostructure for Ultrasensitive Photodetector

2D transition metal dichalcogenide (2D-TMD) materials and their van der Waals heterostructures (vdWHs) have inspired worldwide efforts in the fields of electronics and optoelectronics. However, photodetectors based on 2D/2D vdWHs suffer from performance limitations due to the weak optical absorption of their atomically thin nature. In this work, taking advantage of an excellent light absorption coefficient, low-temperature solution-processability, and long charge carrier diffusion length, all-inorganic halides perovskite CsPbI3- x Br x quantum dots are integrated with monolayer MoS2 for high-performance and low-cost photodetectors. A favorable energy band alignment facilitating interfacial photocarrier separation and efficient carrier injection into the MoS2 layer inside the 0D-2D mixed-dimensional vdWHs are confirmed by a series of optical characterizations. Owing to the synergistic effect of the photogating mechanism and the modulation of Schottky barriers, the corresponding phototransistor exhibits a high photoresponsivity of 7.7 × 104 A W-1, a specific detectivity of ≈5.6 × 1011 Jones, and an external quantum efficiency exceeding 107%. The demonstration of such 0D-2D mixed-dimensional heterostructures proposed here would open up a wide realm of opportunities for designing low-cost, flexible transparent, and high-performance optoelectronics.

Solid and macroporous Fe3C/N-C nanofibers with enhanced electromagnetic wave absorbability

A series of solid and macroporous N-doped carbon nanofibers composed of Fe₃C nanoparticles (named as solid Fe₃C/N-C NFs, solid Fe₃C/N-C NFs-1, solid Fe₃C/N-C NFs-2, macroporous Fe₃C/N-C NFs, macroporous Fe₃C/N-C NFs-1 and macroporous Fe₃C/N-C NFs-2, respectively) were prepared through carbonization of as-electrospun nanofiber precursors. The results show that the magnetic Fe₃C nanoparticles (NPs) dispersed homogeneously on the N-doped carbon fibers; as-prepared six materials exhibit excellent microwave absorption with a lower filler content in comparison with other magnetic carbon hybrid nanocomposites in related literatures. Particularly, the solid Fe₃C/N-C NFs have an optimal reflection loss value (RL) of −33.4 dB at 7.6 GHz. For solid Fe₃C/N-C NFs-2, the effective absorption bandwidth (EAB) at RL value below −10 dB can be up to 6.2 GHz at 2 mm. The macroporous Fe₃C/N-C NFs have a broadband absorption area of 4.8 GHz at 3 mm. The EAB can be obtained in the 3.6–18.0 GHz frequency for the thickness of absorber layer between 2 and 6 mm. These Fe₃C–based nanocomposites can be promising as lightweight, effective and low-metal content microwave absorption materials in 1–18 GHz.

Incidence of hepatitis B virus infection in young Chinese blood donors born after mandatory implementation of neonatal hepatitis B vaccination nationwide

This study was carried out to determine the incidence of hepatitis B virus (HBV) infection in the young generation born after mandatory implementation of hepatitis B vaccination since 1992. Repeat blood donors born between 1992 and 1997 were enrolled, who gave blood at least twice during the past 3 years. Donors were tested for HBV infection markers of HBsAg, anti-HBc, anti-HBs and viral DNA by immunoassays (EIAs) and nucleic acid tests (NAT). A total of 14 937 pre-donation screening qualified young repeat donors aged 18-23 years were tested with 9 (0.06%) being HBsAg by EIA and 10 (1:1494) HBV DNA positive by Ultrio NAT (10.4 IU/mL), respectively. HBV DNA was further detected in 1:192 (9/1732) anti-HBc+ repeat donors with Ultrio Plus NAT (3.4 IU/mL). Most cases were identified as occult HBV infection (OBI). Of 14 937 repeat donors, 20.9% were anti-HBc+ positive, while approximately 50% of 12 024 repeat donors were anti-HBs negative or had levels <100 IU/L. HBsAg+ or OBI strains were classified as wild type of genotype B or genotype C. Incident HBV infection in repeat donors was approximately 1:18.5 person-years (1.1%/year) but significantly less frequent in donors with confirmed HBV vaccination (2.4%-3.3%) than those unsure of vaccination status (10.5%; P = .0023). Hepatitis B virus vaccination appears largely protective of HBV infection, but incidence of infections increases in young adults with mostly undetectable or low anti-HBs or occasionally high anti-HBs. A boost of hepatitis B vaccine for adolescents prior to age 18 years may reduce HBV infection, and implementation of more sensitive NAT in blood donation screening may improve HBV safety in blood transfusion.

In Situ Preparation of Cobalt Nanoparticles Decorated in N-Doped Carbon Nanofibers as Excellent Electromagnetic Wave Absorbers

Electrospinning and annealing methods are applied to prepare cobalt nanoparticles decorated in N-doped carbon nanofibers (Co/N-C NFs) with solid and macroporous structures. In detail, the nanocomposites are synthesized by carbonization of as-electrospun polyacrylonitrile/cobalt acetylacetonate nanofibers in an argon atmosphere. The solid Co/N-C NFs have lengths up to dozens of microns with an average diameter of ca. 500 nm and possess abundant cobalt nanoparticles on both the surface and within the fibers, and the cobalt nanoparticle size is about 20 nm. The macroporous Co/N-C NFs possess a hierarchical pore structure, and there are macropores (500 nm) and mesopores (2-50 nm) existing in this material. The saturation magnetization ( M_s) and coercivity ( H_c) of the solid Co/N-C NFs are 28.4 emu g^-1 and 661 Oe, respectively, and those of the macroporous Co/N-C NFs are 23.3 emu g^-1 and 580 Oe, respectively. The solid Co/N-C NFs exhibit excellent electromagnetic wave absorbability, and a minimum reflection loss (RL) value of -25.7 dB is achieved with a matching thickness of 2 mm for solid Co/N-C NFs when the filler loading is 5 wt %, and the effective bandwidth (RL ≤ -10 dB) is 4.3 GHz. Moreover, the effective microwave absorption can be achieved in the whole range of 1-18 GHz by adjusting the thickness of the sample layer and content of the dopant sample.

Regulatory network analysis of LINC00472, a long noncoding RNA downregulated by DNA hypermethylation in colorectal cancer

Colorectal cancer (CRC), one of the common malignant cancers in the world, is caused by accumulated alterations of genetic and epigenetic factors over a long period of time. Along with that protein-coding genes being identified as oncogenes or tumor suppressors in CRC, a number of lncRNAs have also been found to be associated with CRC. Considering the important regulatory role of lncRNAs, the first goal of this study was to identify CRC-associated lncRNAs from a public database. One such lncRNA, LINC00472, was verified to be downregulated in CRC cell lines and cancer tissues compared with adjacent tissues. In addition, the down-regulation of LINC00472 seemed to be caused by DNA hypermethylation at its promoter region. Furthermore, the expression of LINC00472 and DNA methylation of promoter were significantly correlated with clinicopathological features. And DNA hypermethylation of LINC00472 may serve as a better diagnostic biomarker than its expression for CRC. Finally, we predicted the functions of LINC00472 and constructed a regulatory network and found LINC00472 may be involved in cell cycle and cell proliferation processes. Our results may provide a clue to further research into the function and regulatory mechanism of LINC00472 in CRC.

Enhanced field emission properties of graphene-based cathodes fabricated by ultrasonic atomization spray

Ultrasonic atomization spray endowed graphene cathodes with roughened 3-D array-like surface geometry which greatly enhanced electron emission.

Ferroelectric polarization-enhanced charge separation in a vanadium-doped ZnO photoelectrochemical system

A ferroelectric polarization protocol was demonstrated to be favorable for photoinduced charge separation in the V-doped ZnO based photoelectrochemical system.

Investigation of significant microRNA-mRNA pairs associated with nonspecific digestive disorder in rabbits

Nonspecific digestive disorders (NSDD) are one of the major intestinal problems in rabbit, with considerable economic losses in industrial rabbit farms. MicroRNAs (miRNAs), as small non-coding RNAs, have significant biological involvement in intestinal disorders. In this study, we investigated the expression levels of 25 genes and 25 miRNAs in ileum, rabbit sacculus rotundus (RSR) and colon tissues from 9 rabbits with different severity of NSDD. These molecules have been found to be related to NSDD or inflammatory bowel disease, which will help recognise the miRNA-mRNA pairs. Finally, 108 possible pairs of miRNA-mRNA pairs with an anti-correlation were identified by Pearson’s correlation analysis between differentially expressed 25 miRNAs and 23 mRNAs. Ninety-five of these miRNA-mRNA pairs were hitherto unexplored, and their roles in NSDD biology require further elucidation. Our results give a clue to the potential miRNA-mRNA pairs for the NSDD that can further improve the understanding of the pathogenesis of NSDD in rabbit.

Bioinspired Tribotronic Resistive Switching Memory for Self-Powered Memorizing Mechanical Stimuli

Haptic memory, from the interaction of skin and brain, can not only perceive external stimuli but also memorize it after removing the external stimuli. For the mimicry of human sensory memory, a self-powered artificial tactile memorizing system was developed by coupling bionic electronic skin and nonvolatile resistive random access memory (RRAM). The tribotronic nanogenerator is utilized as electronic skin to transform the touching signal into electric pulse, which will be programmed into the artificial brain: RRAM. Because of the advanced structural designs and accurate parameter matching, including the output voltages and the resistances in different resistive states, the artificial brain can be operated in self-powered mode to memorize the touch stimuli with the responsivity up to 20 times. For demonstrating the application potential of this system, it was fabricated as an independently addressed matrix to realize the memorizing of motion trace in two-dimensional space. The newly designed self-powered nonvolatile system has broad applications in next-generation high-performance sensors, artificial intelligence, and bionics.