Nonvolatile logic devices have attracted intensive research attentions recently for energy efficiency computing, where data computing and storage can be realized in the same device structure. Various ...approaches have been adopted to build such devices; however, the functionality and versatility are still very limited. Here, 2D van der Waals heterostructures based on direct bandgap materials black phosphorus and rhenium disulfide for the nonvolatile ternary logic operations is demonstrated for the first time with the ultrathin oxide layer from the black phosphorus serving as the charge trapping as well as band‐to‐band tunneling layer. Furthermore, an artificial electronic synapse based on this heterostructure is demonstrated to mimic trilingual synaptic response by changing the input base voltage. Besides, artificial neural network simulation based on the electronic synaptic arrays using the handwritten digits data sets demonstrates a high recognition accuracy of 91.3%. This work provides a path toward realizing multifunctional nonvolatile logic‐in‐memory applications based on novel 2D heterostructures.
Multifunctional nonvolatile logic‐in‐memory applications based on novel 2D black phosphorus/rhenium disulfide heterostructures are demonstrated. Nonvolatile ternary logic operations are realized for the first time with the ultrathin oxide layer from the BP serving as the charge‐trapping layer with efficient band‐to‐band tunneling. Furthermore, an artificial electronic synapse based on the heterostructures is demonstrated to mimic trilingual synaptic response.
Plasmon is the quantum of the collective oscillation of electrons. How plasmon loses its energy (or damping) plays a pivotal role in plasmonic science and technology. Graphene plasmon is of ...particular interest, partly because of its potentially low damping rate. However, to date, damping pathways have not been clearly unravelled experimentally. Here, we demonstrate mid-infrared (4-15 µm) plasmons in graphene nanostructures with dimensions as small as 50 nm (with a mode area of ∼1 × 10-3 µm2 ). We also reveal damping channels via graphene intrinsic optical phonons and scattering from the edges. Plasmon lifetimes of 20 fs or less are observed when damping via the emission of graphene optical phonons is allowed. Furthermore, surface polar phonons in the SiO2 substrate under graphene nanostructures lead to a significantly modified plasmon dispersion and damping, in contrast to the case of a nonpolar diamond-like-carbon substrate. Our study paves the way for applications of graphene in plasmonic waveguides, modulators and detectors from sub-terahertz to mid-infrared regimes.
A high-quality junction between graphene and metallic contacts is crucial in the creation of high-performance graphene transistors. In an ideal metal-graphene junction, the contact resistance is ...determined solely by the number of conduction modes in graphene. However, as yet, measurements of contact resistance have been inconsistent, and the factors that determine the contact resistance remain unclear. Here, we report that the contact resistance in a palladium-graphene junction exhibits an anomalous temperature dependence, dropping significantly as temperature decreases to a value of just 110 ± 20 Ω µm at 6 K, which is two to three times the minimum achievable resistance. Using a combination of experiment and theory we show that this behaviour results from carrier transport in graphene under the palladium contact. At low temperature, the carrier mean free path exceeds the palladium-graphene coupling length, leading to nearly ballistic transport with a transfer efficiency of ~75%. As the temperature increases, this carrier transport becomes less ballistic, resulting in a considerable reduction in efficiency.
Abstract
Atomically-thin layered molybdenum disulfide (MoS
2
) has attracted tremendous research attention for their potential applications in high performance DC and radio frequency electronics, ...especially for flexible electronics. Bilayer MoS
2
is expected to have higher electron mobility and higher density of states with higher performance compared with single layer MoS
2
. Here, we systematically investigate the synthesis of high quality bilayer MoS
2
by chemical vapor deposition on molten glass with increasing domain sizes up to 200 μm. High performance transistors with optimized high-
κ
dielectrics deliver ON-current of 427 μA μm
−1
at 300 K and a record high ON-current of 1.52 mA μm
−1
at 4.3 K. Moreover, radio frequency transistors are demonstrated with an extrinsic high cut-off frequency of 7.2 GHz and record high extrinsic maximum frequency of oscillation of 23 GHz, together with gigahertz MoS
2
mixers on flexible polyimide substrate, showing the great potential for future high performance DC and high-frequency electronics.
Abstract
Cyclin D1 is one of the most important oncoproteins that drives cancer cell proliferation and associates with tamoxifen resistance in breast cancer. Here, we identify a lncRNA, DILA1, ...which interacts with Cyclin D1 and is overexpressed in tamoxifen-resistant breast cancer cells. Mechanistically, DILA1 inhibits the phosphorylation of Cyclin D1 at Thr286 by directly interacting with Thr286 and blocking its subsequent degradation, leading to overexpressed Cyclin D1 protein in breast cancer. Knocking down DILA1 decreases Cyclin D1 protein expression, inhibits cancer cell growth and restores tamoxifen sensitivity both in vitro and in vivo. High expression of DILA1 is associated with overexpressed Cyclin D1 protein and poor prognosis in breast cancer patients who received tamoxifen treatment. This study shows the previously unappreciated importance of post-translational dysregulation of Cyclin D1 contributing to tamoxifen resistance in breast cancer. Moreover, it reveals the novel mechanism of DILA1 in regulating Cyclin D1 protein stability and suggests DILA1 is a specific therapeutic target to downregulate Cyclin D1 protein and reverse tamoxifen resistance in treating breast cancer.
This study aimed to describe the prevalence and risk factors of prehypertension and hypertension in Jiangxi Province, China. Individuals with prehypertension frequently progress into hypertension and ...are at high risk of developing cardiovascular disease and stroke.
A cross-sectional survey of 15,296 participants (15 years or older) was conducted in Jiangxi Province, China, in 2013, using questionnaire forms and physical measurements.
The prevalence of prehypertension and hypertension was 32.3% (39.2% in men and 27.6% in women) and 29.0% (30.1% in men and 28.2% in women), respectively. The awareness, treatment, and control rates among all hypertensive participants were 64.8%, 27.1%, and 12.6%, respectively. The prevalence of prehypertension in males declined with age, but the prevalence of hypertension increased in different genders. The prevalence of prehypertension and hypertension increased with increasing body mass index (BMI). The prevalence of prehypertension decreased, in parallel to an increase in the prevalence of hypertension, with increasing waist circumference (WC). A combination of WC and BMI was superior to individual indices in identifying hypertension. A multivariate logistic regression analysis indicated that increasing age, high BMI, high visceral adipose index, and high heart rate were risk factors for prehypertension and hypertension. The high body fat percentage was significantly associated with prehypertension. Living in an urban area, male sex, abdominal obesity, and menopause were correlated with hypertension.
Prehypertension and hypertension are epidemic in southern China. Further studies are needed to explore an indicator that can represent the visceral fat accurately and has a close relationship with cardiovascular disease.
Permeable reactive bio-barriers (Bio-PRBs) are a new and developing technique for in situ remediation of groundwater contamination. Some remediation technologies have often been impeded by ...insufficient understanding of contaminant transport and transformation in the subsurface environment. Therefore, advanced knowledge in contaminant transport and reactions in Bio-PRBs will be crucial to the successful practical application of this technique. A two-dimensional reaction model C1 was developed for predicting the multi-path chain kinetic reaction of 1,1,1-trichloroethane (1,1,1-TCA) in Bio-PRBs. This study demonstrates that model C1 is able to predict the 1,1,1-TCA breakthrough time and rapidly evaluate the Bio-PRBs retardation performance. The results show that microbial growth and immobilization are the key factors that affect the retardation and remediation performance of Bio-PRBs. The free growth of microorganisms had significant negative effects on hydraulic conductivity (K) in the zero-valent iron (ZVI) region of free microorganism Bio-PRBs (FM-PRBs). The total head loss in the FM-PRB was 9.0 cm, which was significantly greater than the head loss (6.5 cm) of immobilized microorganism Bio-PRBs (IM-PRBs). Compared to ZVI-PRBs and FM-PRBs, the numerical simulation results reveal that microbial immobilization significantly improves the remediation performance of IM-PRBs by 550.9% and 32.7%, respectively. The dual effect of microorganisms leads to significant differences in the 1,1,1-TCA and daughter products (1,1-dichloroethane, 1,1-dichloroethene, chloroethane and vinyl chloride) contaminant-plume evolution between FM-PRBs and IM-PRBs. In addition, model C1 can be utilized to design standard Bio-PRBs for real site of 1,1,1-TCA contanminated groundwater. To meet the safety standard of groundwater as potable water, the width of IM-PRBs needs to be increased by 24 cm. However, in FM-PRBs, the width needs to be increased by 42 cm. Therefore, IM-PRBs save costs significantly. This work has successfully used a model to optimize Bio-PRBs and to predict 1,1,1-TCA and daughter products contaminant-plume evolution in different Bio-PRBs.
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•The different Bio-PRBs performance could be fast evaluated by the reaction model.•Microorganism had dual effect on 1,1,1-TCA and daughter products contaminant-plume evolution.•Microorganism immobilization was the critical step to improve Bio-PRBs performance.•Multi-path reaction model could be as a tool to develop more cost-effective and competitive Bio-PRBs.
The purpose of this study is to assess the prevalence of overweight/obesity, abdominal obesity and obesity-related risk factors in southern China.
A cross-sectional survey of 15,364 participants aged ...15 years and older was conducted from November 2013 to August 2014 in Jiangxi Province, China, using questionnaire forms and physical measurements. The physical measurements included body height, weight, waist circumference (WC), body fat percentage (BFP) and visceral adipose index (VAI). Multivariate logistic regression analysis was performed to evaluate the risk factors for overweight/obesity and abdominal obesity.
The prevalence of overweight was 25.8% (25.9% in males and 25.7% in females), while that of obesity was 7.9% (8.4% in males and 7.6% in females). The prevalence of abdominal obesity was 10.2% (8.6% in males and 11.3% in females). The prevalence of overweight/obesity was 37.1% in urban residents and 30.2% in rural residents, and this difference was significant (P < 0.001). Urban residents had a significantly higher prevalence of abdominal obesity than rural residents (11.6% vs 8.7%, P < 0.001). Among the participants with an underweight/normal body mass index (BMI), 1.3% still had abdominal obesity, 16.1% had a high BFP and 1.0% had a high VAI. Moreover, among obese participants, 9.7% had a low /normal WC, 0.8% had a normal BFP and 15.9% had a normal VAI. Meanwhile, the partial correlation analysis indicated that the correlation coefficients between VAI and BMI, VAI and WC, and BMI and WC were 0.700, 0.666, and 0.721, respectively. A multivariate logistic regression analysis indicated that being female and having a high BFP and a high VAI were significantly associated with an increased risk of overweight/obesity and abdominal obesity. In addition, living in an urban area and older age correlated with overweight/obesity.
This study revealed that obesity and abdominal obesity, which differed by gender and age, are epidemic in southern China. Moreover, there was a very high, significant, positive correlation between WC, BMI and VAI. However, further studies are needed to explore which indicator of body fat could be used as the best marker to indirectly reflect cardiometabolic risk.
Grain size effects on the physical properties of polycrystalline ferroelectrics have been extensively studied for decades; however there are still major controversies regarding the dependence of the ...piezoelectric and ferroelectric properties on the grain size. Dense BaTiO3 ceramics with different grain sizes were fabricated by either conventional sintering or spark plasma sintering using micro- and nano-sized powders. The results show that the grain size effect on the dielectric permittivity is nearly independent of the sintering method and starting powder used. A peak in the permittivity is observed in all the ceramics with a grain size near 1 μm and can be attributed to a maximum domain wall density and mobility. The piezoelectric coefficient d33 and remnant polarization Pr show diverse grain size effects depending on the particle size of the starting powder and sintering temperature. This suggests that besides domain wall density, other factors such as back fields and point defects, which influence the domain wall mobility, could be responsible for the different grain size dependence observed in the dielectric and piezoelectric/ferroelectric properties. In cases where point defects are not the dominant contributor, the piezoelectric constant d33 and the remnant polarization Pr increase with increasing grain size.
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