Improving mobility of silicon metal-oxide-semiconductor devices for quantum dots by high vacuum activation annealing

To improve mobility of fabricated silicon metal-oxide-semiconductor (MOS) quantum devices, forming gas annealing is a common method used to mitigate the effects of disorder at the Si/SiO2 interface. However, the importance of activation annealing is usually ignored. Here, we show that a high vacuum environment for implantation activation is beneficial for improving mobility compared to nitrogen atmosphere. Low-temperature transport measurements of Hall bars show that peak mobility can be improved by a factor of two, reaching 1.5 m^2/(Vs) using high vacuum annealing during implantation activation. Moreover, the charge stability diagram of a single quantum dot is mapped, with no visible disturbance caused by disorder, suggesting possibility of fabricating high-quality quantum dots on commercial wafers. Our results may provide valuable insights into device optimization in silicon-based quantum computing.Comment: 13 pages, 4 figure

tert-Butyl 6-amino-3,4-dihydro-2H-1,4-benzoxazine-4-carboxyl­ate

The title mol­ecule, C13H18N2O3, contains a benzene ring fused to an oxazine ring and one tert-but­oxy­carbonyl group bound to the N atom of the oxazine ring. A weak intra­molecular C—H⋯O inter­action occurs. In the crystal, inter­molecular N—H⋯O and C—H⋯O hydrogen bonds stack the mol­ecules down the b axis. Weak C—H⋯N contacts connect the stacks, generating a three-dimensional network

Comparative genomics suggests that an ancestral polyploidy event leads to enhanced root nodule symbiosis in the Papilionoideae

Root nodule symbiosis (RNS) is one of the most efficient biological systems for nitrogen fixation and it occurs in 90% of genera in the Papilionoideae, the largest subfamily of legumes. Most papilionoid species show evidence of a polyploidy event occurred approximately 58 million years ago. Although polyploidy is considered to be an important evolutionary force in plants, the role of this papilionoid polyploidy event, especially its association with RNS, is not understood. In this study, we explored this role using an integrated comparative genomic approach and conducted gene expression comparisons and gene ontology enrichment analyses. The results show the following: (1) approximately a quarter of the papilionoid-polyploidy-derived duplicate genes are retained; (2) there is a striking divergence in the level of expression of gene duplicate pairs derived from the polyploidy event; and (3) the retained duplicates are frequently involved in the processes crucial for RNS establishment, such as symbiotic signalling, nodule organogenesis, rhizobial infection and nutrient exchange and transport. Thus, we conclude that the papilionoid polyploidy event might have further refined RNS and induced a more robust and enhanced symbiotic system. This conclusion partly explains the widespread occurrence of the Papilionoideae

Homage to Professor Shinko Ogiwara

<p><b><i>Primula undulifolia</i> sp. nov.</b> (A) Habit in Flowering; (B) Type Locality; (C) Calyx; (D) Pin and Thrum Flowers; (E) Leaf. Photographed by Yuan XU.</p

Optimization of a continuous flow electrocoagulation as pretreatment for membrane distillation of the waste stream in vinyl ester resin production

Vinyl ester resin production wastewater (VERW) contains high concentrations of organics particularly, methacrylic acid and bisphenol A, which are hazardous chemicals and harmful to the aquatic environment. Therefore, there is an urgent need to properly treat the effluent before discharge into the aquatic system. In this work, direct contact membrane distillation (DCMD) was explored as an advanced treatment of the VERW pre-treated by a continuous flow electrocoagulation (EC) and peroxi-electrocoagulation (PEC) processes. Optimization of EC and PEC processes were investigated and the DCMD performance was evaluated. Results showed that the optimal value of current density and polyacrylamide (PAM) dosage was 15 mA/cm2 and 1 mg/L, respectively in the EC process. For the PEC process, the optimal addition of hydrogen peroxide (H2O2) dosage was four times of the chemical oxygen demand (COD) concentration of EC effluent. The COD of VERW was effectively removed via EC followed by PEC (EC-PEC), resulting in the significant alleviation of membrane fouling during DCMD filtration of VERW. The initial flux of DCMD filtration of VERW pre-treated via EC-PEC improved by 35%, compared that only pre-treated by EC. Moreover, the concentration factor (CF) of the DCMD system reached up to 8.1 and the conductivity of distillate was less than 33.2 μS/cm. Hence, the EC and membrane distillation hybrid process paves a new way for the effective treatment of waste steam from resin production.</p

Optimization of a continuous flow electrocoagulation as pretreatment for membrane distillation of the waste stream in vinyl ester resin production

Vinyl ester resin production wastewater (VERW) contains high concentrations of organics particularly, methacrylic acid and bisphenol A, which are hazardous chemicals and harmful to the aquatic environment. Therefore, there is an urgent need to properly treat the effluent before discharge into the aquatic system. In this work, direct contact membrane distillation (DCMD) was explored as an advanced treatment of the VERW pre-treated by a continuous flow electrocoagulation (EC) and peroxi-electrocoagulation (PEC) processes. Optimization of EC and PEC processes were investigated and the DCMD performance was evaluated. Results showed that the optimal value of current density and polyacrylamide (PAM) dosage was 15 mA/cm2 and 1 mg/L, respectively in the EC process. For the PEC process, the optimal addition of hydrogen peroxide (H2O2) dosage was four times of the chemical oxygen demand (COD) concentration of EC effluent. The COD of VERW was effectively removed via EC followed by PEC (EC-PEC), resulting in the significant alleviation of membrane fouling during DCMD filtration of VERW. The initial flux of DCMD filtration of VERW pre-treated via EC-PEC improved by 35%, compared that only pre-treated by EC. Moreover, the concentration factor (CF) of the DCMD system reached up to 8.1 and the conductivity of distillate was less than 33.2 μS/cm. Hence, the EC and membrane distillation hybrid process paves a new way for the effective treatment of waste steam from resin production.</p

Downregulation of NGAL is Required for the Inhibition of Proliferation and the Promotion of Apoptosis of Human Gastric Cancer MGC-803 Cells

Background/Aims: Gastric cancer is considered as a common malignancy with a poor prognosis as well as unsatisfactory treatment. Neutrophil gelatinase-associated lipocalin (NGAL) has been reported to affect multiple aspects of human tumor, including gastric cancer. This study aims to explore the effects of NGAL gene silencing on the proliferation as well as apoptosis of human gastric cancer MGC-803 cells. Methods: This study included 87 patients with gastric cancer. MGC-803 cells were collected and mainly treated with siRNA against NGAL and recombinant NGAL plasmid. The expression of NGAL mRNA and the expressions of NGAL protein and apoptosis-related proteins were determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis, respectively. Cell cycle and apoptosis were tested by flow cytometry, and cell proliferation was detected by water soluble tetrazolium-1 (WST-1) assay. The effect of NGAL gene silencing on tumorigenicity of MGC-803 cells in vivo was detected through establishment of xenograft in nude mice. Results: NGAL was highly expressed in gastric cancer tissues. The protein and mRNA expressions of NGAL gene in MGC-803 cells treated with NGAL-siRNA were obviously reduced, and the amount of cells in G0/G1 phase was increased. Moreover, MGC-803 cells treated with NGAL-siRNA exhibited inhibited proliferation, enhanced apoptosis, decreased expressions of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) as well as B-cell lymphoma-2 (Bcl-2) and increased expressions of cysteine-aspartic acid specific protease-9 (caspase-9) and Bcl2-associated X (Bax), as well as repressed tumorigenicity in vivo. Conclusion: NGAL gene silencing inhibits proliferation and promotes apoptosis of MGC-803 cells, which can provide a novel theory for treatment of gastric cancer