Magnetic and Ferroelectric Manipulation of Valley Physics in Janus Piezoelectric Materials.

The realization of multiferroic materials offers the possibility of multifunctional electronic device design. However, the coupling between the multiferroicity and piezoelectricity in Janus materials is rarely reported. In this study, we propose a mechanism for manipulating valley physics by magnetization reversing and ferroelectric switching in multiferroic and piezoelectric material. The ferromagnetic VSiGeP4 monolayer exhibits a large valley polarization up to 100 meV, which can be effectively operated by reversing magnetization. Interestingly, the antiferromagnetic VSiGeP4 bilayers with AB and BA stacking configurations allow the coexistence of valley polarization and ferroelectricity, supporting the proposed strategy for manipulating valley physics via ferroelectric switching and interlayer sliding. In addition, the VSiGeP4 monolayer contains remarkable tunable piezoelectricity regulated by electron correlation U. This study proposes a feasible idea for regulating valley polarization and a general design idea for multifunctional devices with multiferroic and piezoelectric properties, facilitating the miniaturization and integration of nanodevices.

Efficient direct conversion of methane into methanol on CuZn hetero-diatomic catalysts with certain coordination spheres: a DFT study.

The oxidation of methane to a high-value-added chemical, methanol, is a major challenge in catalysis, requiring high energy input to overcome the CH3-H bond activation energy barrier. Based on density functional theory (DFT) calculations, methane oxidation to methanol is catalyzed by hetero-diatomic catalysts (CuZn-NG) with different coordination spheres (CSs). Valence band maximum (VBM), atomic charge and d-band center are selected as analysis methods for the pathway selection and activity of catalysis. The VBM plays a vital role in the catalytic pathway selection, CuZn-NG catalyzes the direct conversion of methane into methanol without side reactions. Alarmingly, the most important reaction step, CH3-H bond activation, is a spontaneously exothermic reaction (releasing 0.06 eV) with CuZn-NPAG as the catalyst, in contrast to most other endothermic reactions in the same activation. By analyzing the atomic charge of the Cu center and O atom, the special electronic phenomenon for this important step is summarized as the "bow-release effect". The CS affects the electronic properties of the active center and further affects the methane oxidation activity. This work provides a useful guide to understand the catalytic selectivity and activity of hetero-diatomic catalysts.

The steps and key points of thyroid surgery with lateral cervical incision.

The thyroid surgery with lateral cervical incision uses the sternocleidomastoid intermuscular approach through the gap between band muscles and carotid sheath to reach the surgical field. The recurrent laryngeal nerve and upper and lower parathyroid glands are first identified, the upper pole vessels are severed; then the Berry ligament is separated; the isthmus is severed, and the thyroid gland is finally removed. This approach can avoid the trauma of the skin and muscle tissue in the anterior neck region, to relieve the pressure on the neck and swallowing stretch feeling for patients after surgery. The surgical modality is effective and less time-consuming. This article gives a detailed introduction to the standardized procedures and some key points of thyroid surgery with lateral cervical incision.

High iodine induces DNA damage in autoimmune thyroiditis partially by inhibiting the DNA repair protein MTH1.

This study aims to investigate the level of DNA damage in high iodine (HI)-induced autoimmune thyroiditis (AIT), and to explore the role of DNA repair protein MutT homolog-1 (MTH1) in this process. The levels of pro-inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8 were measured using qRT-PCR and ELISA. The apoptosis was evaluated using TUNEL staining. The pathological changes of thyroid tissues were evaluated using hematoxylin and eosin (HE) staining. The DNA damage was assessed by determining the expression of 8-hydroxy-2'deoxyguanosine (8-OHdG; an indicator of oxidative DNA damage) and performing the Comet assay. Our results showed that both the HI-treated NOD.H-2h4 mice (experimental AIT mice) and the HI-treated mouse thyroid follicular epithelial cells showed enhanced inflammation, apoptosis, and DNA damage level, accompanied by decreased MTH1 expression. Importantly, overexpression of MTH1 effectively abrogated the HI-induced enhancement of inflammation, apoptosis, and DNA damage in mouse thyroid follicular epithelial cells. In conclusion, HI treatment induces DNA damage in AIT, at least in part, by inhibiting the DNA repair protein MTH1.

The CDH1 -160C/A polymorphism is associated with breast cancer: evidence from a meta-analysis.

BACKGROUND: Numerous epidemiological studies have evaluated the association between the CDH1 -160C/A polymorphism and the risk of breast cancers. However, these studies have yielded conflicting results. To derive a more precise estimation of this association, this meta-analysis was conducted. METHODS: A comprehensive search using the keywords "CDH1," "E-Cadherin," "polymorphism," "SNP," and "variant" combined with "breast," "cancer," "tumor," or "carcinomas" was conducted. Pooled odds ratios (ORs) with 95 % confidence intervals (CIs) were appropriately calculated using a fixed effect or random effect model. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2009 checklist was used for this meta-analysis. RESULTS: Four publications including five studies were identified. It was found that the CDH1 -160C/A polymorphism was significantly associated with breast cancer risk in the dominant model (CA + AA vs. CC: OR = 1.207, 95 % CI = 1.031-1.412, P = 0.019). CONCLUSIONS: Our meta-analysis demonstrated that the -160C/A polymorphism in the CDH1 gene might contribute to breast cancer susceptibility. Further investigations using a much larger sample including different ethnicities are still needed to verify this association.

Switch effect on controlled water splitting by biaxial strain regulating the promising two-dimensional Janus X2PAs (X = Si, Ge and Sn) photocatalyst.

Two-dimensional photocatalytic materials with unique properties have been well-reported in recent decades. However, strategies for controlling the photocatalytic process are still ongoing. Herein, Janus X2PAs (X = Si, Ge and Sn) monolayers have been explored by first-principles calculations to meet this challenge. All strain-free X2PAs monolayers exhibit excellent photocatalytic properties with high carrier mobility (2.39 × 102-1.34 × 104 cm2 V-1 s-1), suitable band edge positions straddling the standard redox potential of water and large visible light absorption coefficients (up to 105 cm-1). Most importantly, a reaction switch effect is proposed for the first time towards controlling the microscopic photocatalytic process of water splitting on X2PAs monolayers through macroscopic mechanical strain. This effect renders the Janus X2PAs photocatalytic switches among the states of only oxygen evolution reaction, only hydrogen evolution reaction and the full redox reaction for controlled water splitting. This work not only provides a new avenue for designing highly tunable photocatalysts but also offers new physical insights into controlling the photocatalytic water-splitting reaction.

Sternomastoid intermuscular approach has better postoperative cosmesis and less neck discomfort than linea alba cervicalis approach in hemithyroidectomy: a randomized clinical trial.

BACKGROUND: Surgery is still the most important treatment method for thyroid cancer. The classic linea alba cervicalis approach caused obvious neck scarring. This study explored an alternative open operative approach with concealed incision for hemithyroidectomy, and demonstrated whether it was non-inferior to traditional approach in postoperative complications and operation efficiency. METHODS: Patients ( n =220) from November 2019 to November 2020 willing to undergo hemithyroidectomy because of differentiated thyroid cancer were randomly divided into the sternocleidomastoid intermuscular approach (SMIA) group ( n =110), and the linea alba cervicalis approach (LACA) group ( n =110). The incidence of postoperative complications within 3 months and operation efficiency indicator R0 resection rate were recorded as primary endpoint, while scar apperance was assessed as secondary endpoint. The data were statistically analyzed. RESULTS: The baseline data of these two groups were comparable, with no significant difference ( P >0.05). As primary endpoint, R0 resection rate was 100% in both groups. In the 1-month follow-up period, the SMIA group had a lower score for neck discomfort compared with that of the LACA group (1.01±0.1648 vs. 0.5657±0.0976, P =0.0217). The SMIA group's scar had better results from the observer scar assessment compared to that of the LACA group as secondary endpoint. Within the 3-month follow-up, the total complications were calculated, and it was demonstrated that SMIA was non-inferior to traditional LACA operation ( P of non-inferiority=0.0048). CONCLUSIONS: Compared with LACA group, surgery through the SMIA is safe, effective, and has non-inferior postoperative complications. SMIA can be considered an alternative approach to classic LACA in hemithyroidectomy.

Active Asymmetric Electron-Transfer Effect on the Enhanced Piezoelectricity in MoTO (T = S, Se, or Te) Monolayers and Bilayers.

Development of piezoelectric materials is limited partly due to the incompleteness of internal mechanism and the lack of vertical piezoelectricity. Herein, we theoretically identify the stable MoTO (T = S, Se, or Te) monolayers and bilayers. When two elements are given but another element can be changed, the larger the electronegativity difference ratio Rratio is, the stronger the piezoelectricity will be. Vertical piezoelectric coefficient d33 of the MoTeO bilayer reaches 38.907 pm/V, which is 12 times larger than that of the bulk GaN. The "active asymmetric electron-transfer" strategy mainly contributes to the spontaneous remarkable piezoelectricity of MoTO. Importantly, we proposed the new method for calculating the piezoelectric coefficients of two-dimensional (2D) materials, which corresponds to the fact that 2D materials have a certain thickness. This study not only provides novel extraordinary candidates for energy conversion and touch-sensor nanodevices but also promotes a deeper understanding of piezoelectricity of 2D materials.

Structure and property of propellant based on nitroglycerine/glycerol triacetate mixed plasticizers: molecular dynamics simulation and experimental study.

Molecular dynamics simulation has been used to investigate the influence of nitroglycerine (NG)/glycerol triacetate (GTA) mixed plasticizers on the plasticizing ability of nitrocellulose (NC) binder in solid propellant. The radial distribution function and binding energy indicated that NC/plasticizers blends showed stronger intermolecular interaction of van der Waals and hydrogen bonds. The mean-squared displacements of plasticizers and volume distribution revealed that the mobility of plasticizer GTA in the NC polymer binder was higher than that of NG. Then, the mechanical properties of the propellant based on NG/GTA mixed plasticizers were investigated systematically using experimental and simulation calculation method. The results suggested that the ductility of propellant based on NG/GTA mixed plasticizers was improved, implying that NG/GTA mixed plasticizers have a higher plasticizing efficiency for NC. Furthermore, we conducted experimental studies on the effects of NG/GTA mixed plasticizers on the energy and combustion properties of propellants. It was shown that NG/GTA mixed plasticizers could enhance the combustion efficiency of propellants effectively at low pressures. These computational and experimental studies provided guidance for the application of NG/GTA mixed plasticizers in high-performance propellants.

A turn-on fluorescent sensor for detecting nickel in living cells.

We present the synthesis and properties of Nickelsensor-1 (NS1), a new water-soluble, turn-on fluorescent sensor that is capable of selectively responding to Ni(2+) in aqueous solution and in living cells. NS1 combines a BODIPY chromophore and a mixed N/O/S receptor to provide good selectivity for Ni(2+) over a range of biologically abundant metal ions in aqueous solution. In addition to these characteristics, confocal microscopy experiments further show that NS1 can be delivered into living cells and report changes in intracellular Ni(2+) levels in a respiratory cell model.

Experimental and theoretical study of tunable 1,3-lithium shift of propargylic/allenylic species, transmetallation, and Pd-catalyzed cross-coupling reactions.

The highly selective tuning of the isomerization from 1-arylalka-1,2-dien-1-yllithium to 1-arylalka-1,2-dien-3-yllithium has been realized in the deprotonation of 1-arylalk-1-yne (conditions A and B) and carbolithiation of 1-arylbut-3-en-1-yne with alkyllithium (conditions C and D). Subsequent transmetallation and Pd-catalyzed Negishi coupling reactions afforded 1,1-diaryl or 1,3-diaryl allenes with high selectivity. Deuterium-labeling cross experiments indicated that an intermolecular lithiation process occurred in both 1,3-lithium shift conditions (conditions B and D). 1-Arylalka-1,2-diene was confirmed experimentally to be the intermediate. A computational study at the B3LYP level for the isomerization indicated that the acidity of H at the 3-position is higher than that of the H at the 1-position of 1-phenyl-1,2-butadiene. Under conditions B, iPr(2)NH acts as a proton carrier to finish the 1,3-lithium shift. The overall activation barrier for the rate-determining step in the solvated models is approximately 21.0 kcal mol(-1), indicating that the isomerization is reasonable at room temperature. For the isomerization under conditions D, DFT calculations indicated that the addition of TMEDA (tetramethylethylenediamine) and HMPA (hexamethylphosphoramide) changes the global minimum of the system; among the possible mechanisms (P1-P5) considered, the mechanism catalyzed by dilithiated species (P5) is the most probable one. The overall activation barriers for isomerization in THF and TMEDA solvated models are 22.6 and 19.7 kcal mol(-1), respectively, proving that the isomerization may proceed at RT in THF or at -78 degrees C with TMEDA, due to the fact that the solvation of the additives may increase the concentration of 1-phenyl-1,2-butadienyllithium monomer by a deaggregation effect.

[Expression of NEK-6 in gastric cancer and its clinical significance].

OBJECTIVE: To explore the NEK-6 expression in gastric cancer tissue and its relationship with clinicopathological features. METHODS: Fluorescent quantification PCR and Western blotting were used to examine the NEK-6 expression in 36 samples of fresh gastric cancer tissues and para-cancer gastric mucosal tissues, human gastric cancer cell lines(BGC-823, MKN-28, SGC-7901, MGC-803, HGC-27, AGS), and human normal gastric epithelial cell line (GES-1). Gastric cancer cell lines with the highest expression level were selected to perform the invasion and migration tests, and the effect of down-regulated NEK-6 expression by siRNA transfection on above invasion and migration tests were observed. Meanwhile NEK-6 expression in 94 paraffin samples of gastric cancer tissues was examined by immunohistochemistry and its positivity was compared among different clinicopathologic features. RESULTS: Fluorescent quantification PCR revealed gastric cancer tissues had significantly higher NEK-6 expression than para-cancer tissues(0.002 80±0.001 36 vs. 0.001 91±0.001 48, P<0.05), NEK-6 expression was up-regulated in 31 gastric cancer tissues (86.1%), and human gastric cancer cell lines had significantly higher NEK-6 expression than GES-1 cells, among whom BGC-823 and AGS cell lines were the highest. Invasion and migration tests showed that as compared to negative siRNA control group, ability of invasion and migration in BGC-823 and AGS cells after siRNA transfection was obviously decreased. In 94 paraffin samples, positive expression rate of NEK-6 was 60.6%(57/94), and NEK-6 expression was significantly associated with gastric cancer distant metastasis, lymph nodes metastasis and TNM staging(all P<0.05). CONCLUSIONS: NEK-6 expression is up-regulated in gastric cancer tissues, which is significantly associated with distant metastasis, lymph nodes metastasis and TNM staging. Down-regulation of NEK-6 expression can inhibit the ability of invasion and migration in gastric cancer cells.

Preparation and use of Leadfluor-1, a synthetic fluorophore for live-cell lead imaging.

Leadfluor-1 (LF1) is a small-molecule fluorescent sensor for detecting lead in biological and environmental samples, including live cells. This dye uses a xanthenone fluorescent scaffold coupled to a dicarboxylate pseudocrown ether receptor to achieve selective detection of Pb(2+) in the presence of biologically relevant metal ions, including divalent calcium, magnesium and zinc. LF1 fluorescence increases by up to 18-fold on binding Pb(2+). In this protocol, we describe the synthesis and application of LF1 to imaging lead accumulation within live cells. The preparation of LF1 is anticipated to take 14-21 d, and the imaging assays can be performed in 1-2 d with cultured cells.

A selective fluorescent sensor for detecting lead in living cells.

We present the synthesis, properties, and biological applications of Leadfluor-1 (LF1), a new water-soluble, turn-on fluorescent sensor that is capable of selectively imaging Pb2+ in aqueous solution and in living cells. LF1 combines a fluorescein chromophore and a pseudocrown receptor to provide good selectivity for Pb2+ over a range of biologically and environmentally relevant metal ions in aqueous solution, with sensitivity to parts per billion EPA limits for allowable lead in drinking water. In addition to these attributes, imaging experiments further show that LF1 is the first small-molecule reagent that can be delivered into living cells and report changes in intracellular Pb2+ levels.

Pd(0)-catalyzed highly selective synthesis of 1,1-diarylpropadienes and 1,3-diarylpropynes from 1-aryl-1-propynes and aryl halides.

Under different reaction conditions, 1,1-diarylpropadienes and 1,3-diarylpropynes can be prepared respectively by the sequential lithiation of 1-aryl-1-propynes, transmetalation, and the corresponding Pd(0)-catalyzed cross-coupling with aryl halides. A rationale for the formation of 1,3-diarylpropynes is proposed.