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Halide perovskites are revolutionizing the renewable energy sector owing to their high photovoltaic efficiency, low manufacturing cost, and flexibility. Their remarkable mobility and long carrier lifetime are also valuable for information technology, but fundamental challenges like poor stability under an electric field prevent realistic applications of halide perovskites in electronics. Here, it is discovered that valleytronics is a promising route to leverage the advantages of halide perovskites and derivatives for information storage and processing. The synthesized all-inorganic lead-free perovskite derivative, Cs3 Bi2 I9 , exhibits strong light-matter interaction and parity-dependent optically addressable valley degree of freedom. Robust optical helicity in all odd-layer-number crystals with inversion symmetry breaking is observed, indicating excitonic coherence extending well beyond 11 layers. The excellent optical and valley properties of Cs3 Bi2 I9 arise from the unique parallel bands, according to first principles calculations. This discovery points to new materials design principles for scalable valleytronic devices and demonstrates the promise of perovskite derivatives beyond energy applications.

Tremella fuciformis is an edible white jelly mushroom with medicinal qualities. The formation of T. fuciformis fruiting bodies is highly dependent on the presence of Annulohypoxylon stygium under natural conditions and during artificial cultivation. A lack of efficient transformation systems restricts the ability of researchers to functionally characterize the genes in these two interacting fungi. In this study, we tested the utility of the Agrobacterium tumefaciens-mediated transformation of T. fuciformis and A. stygium protoplasts. A. tumefaciens strain EHA105 cells harboring the pTrGEH plasmid, which contains genes for enhanced green fluorescent protein (egfp) and hygromycin B phosphotransferase (hph), was co-cultured with T. fuciformis protoplasts. Meanwhile, EHA105 cells harboring the pAnGRH plasmid, which contains the red fluorescent protein (rfp) and hph genes, was co-cultured with A. stygium protoplasts. The egfp, rfp, and hph genes were under the control of the promoter for gpd, which encodes glyceraldehyde-3-phosphate dehydrogenase. Optimal co-cultivation was achieved with a 1:1 mixture of bacteria (OD600 0.4-0.6) and fungal protoplasts (105/mL) incubated at 25°C in a medium containing 200 μM acetosyringone. The subsequent selection on hygromycin B-containing medium yielded 45 and 187 stable transformants per 105 protoplasts for T. fuciformis and A. stygium, respectively. The integration of the transformed DNA into the two fungal genomes was confirmed by polymerase chain reaction (PCR), Southern blot analysis, fluorescence imaging, and a quantitative real-time PCR. All results confirmed the feasibility of our transformation approach, which may facilitate future functional analyses of T. fuciformis and A. stygium genes.

Background It is believed that there is a certain correlation between the brain and kidneys, but it is poorly understood. Many findings suggested that there were previously unknown signaling pathways involving AβPP and BACE1 in the kidney. Objective Exploring the changes of BACE1 activity in APP23 mouse kidneys, providing evidence for the function of AβPP and BACE1 activity in the kidney. Methods The activity and expression of BACE1 were detected in the kidney of APP23 mice by enzymatic assay and western blotting. The protein expression levels of AβPP, claudin1, occludin, VE-cadherin, and Klotho (membrane-form klotho) were examined by using western blotting. The renal pathological changes of APP23 mice were examined by the routine renal pathological procedures. Results In this study, we found that the AβPP protein level was increased in kidneys of APP23 mice compared with wild-type (WT) mice. Additionally, the activity and expression of BACE1 were increased in kidneys of APP23 mice compared to that of WT. BACE1 was predominantly distributed on the lumen side of renal tubular epithelial cells. The protein levels of Klotho and VE-cadherin were decreased, occludin expression was also decreased, and claudin-1 expression was increased. Renal pathological damage which observed in kidneys of APP23 mice was more serious than that in kidneys of WT mice. Conclusion Our findings suggest that the increase of AβPP protein levels under Thy-1 neuron promoter in the APP23 mice promoted the increase of renal BACE1 expression and enzymatic activity in the kidneys. Moreover, certain pathological damage in the kidneys of APP23 mice were observed. APP23 mice are easily affected by external risk factors compared with WT mice.

We directly transduce valley information into mechanical states in a monolayer M0S2 resonator. The valley-mechanical interaction is achieved under a magnetic gradient and the valley- actuated mechanical motion is detected by laser interferometry.

Energy internet (EI) is the framework foundation for tackling climate change and environmental issues and achieving “carbon peak and carbon neutral”. In this paper, considering the important function of pumped-storage power station (PPS) in promoting the “source-grid-load-storage” synergy and complement in the construction of EI, a novel evaluation index system and evaluation model for the site selection of PPS is proposed to provide decision support for the orderly construction of EI. Firstly, compatible with traditional engineering construction factors and multi-energy complementary needs, a systematic evaluation index system of PPS site selection is established from hydrological conditions, topographical and geological conditions, construction conditions, power grid development planning and economic and environmental benefits. Secondly, considering the inconsistency of conclusions of a single evaluation method, the cycle elimination mechanism based on Kendall’s concordance coefficient (KCC) is introduced into the combination evaluation model of PPS site selection, and the validity measurement method of the model is defined. Finally, a case study on the site selection of PPS in Hebei province of China is carried out to verify the effectiveness of the combination evaluation model, and the sensitivity analysis is carried out. The research shows that it is highly feasible to use the index and model constructed in this paper for the site selection of PPS. The combination evaluation model based on cycle elimination solves the inconsistency of the evaluation conclusions and greatly improves the effectiveness of the combination evaluation model.

Background/Aims: IgA nephropathy is the most prevalent form of primary glomerulonephritis worldwide. Among patients with kidney disease, hypertension is one of the most important risk factors of disease progression. Considering the limited evidence regarding the appropriate blood pressure (BP) goal for patients with IgA nephropathy, our aim was to critically appraise the potential BP goal in IgA nephropathy. Methods: We performed a retrospective analysis of the BP data from 1055 patients with IgA nephropathy, extracted from the database of a nationwide, multi-center, cross-sectional study, including 61 tertiary hospitals in China. Hypertension was defined by a BP ≥140/90 mmHg. Three BP cutoff levels were evaluated as control values: < 140/90 mmHg, < 130/80 mmHg and < 125/75 mmHg. The primary outcome of our study was the prevalence of BP control among patients with a 24-h proteinuria < 1 g/d or ≥ 1 g/d. Multivariate logistic regression analysis was used to identify demographic and clinical factors associated with a decrease in renal function for the different target levels of BP. Results: The overall prevalence of hypertension was 63.3%. BP was controlled under 140/90 mmHg in 49.1% of patients, with 34.3% of patients with proteinuria < 1 g/d reaching the target BP < 130/80 mmHg and only 12.9% of patients with proteinuria > 1 g/d achieving a BP < 125/75 mmHg. Among patients with proteinuria < 1 g/d, the adjusted odds ratios (OR) and 95% confidence interval (95% CI) of a decrease in renal function, for the 3 target BP levels, were as follows (P > 0.05): < 140/90 mmHg, 0.9 (0.5 - 1.6); < 130/80 mmHg, 1.0 (0.5 - 1.8); and < 125/75 mmHg, 1.0 (0.5 - 2.0). With proteinuria ≥1 g/d, the adjusted ORs (95%CI) of attaining the BP targets of < 140/90 mmHg, < 130/80 mmHg and < 125/75 mmHg were 0.4 (0.2 - 0.6), 0.2 (0.1 - 0.4) and 0.3 (0.1 - 0.5), respectively (P < 0.05). Conclusion: Hypertension was common in IgA nephropathy and hypertensive control was suboptimal. Our result supports a benefit of intensive control of BP < 130/80 mmHg for patients with proteinuria ≥1 g/d. However, in patients with proteinuria < 1 g/d, a renoprotective effect of this BP goal was not identified.

Purpose Hazard assessment on drought disaster is of great significance for improving drought risk management. Due to the complexity and uncertainty of the drought disaster, the index values have some grey multi-source heterogeneous characteristics. The purpose of this paper is to construct a grey projection incidence model (GPIM) to evaluate the hazard of the drought disaster characterised by the grey heterogeneity information. Design/methodology/approach First, the index system of the drought hazard risk is established based on the formation mechanism of the drought disaster. Then, the GPIM for the heterogeneous panel data is constructed to assess drought hazard of five cities in Henan Province. Subsequently, based on the assessment results, the grey clustering model is employed for the regional division. Findings The findings demonstrate that five cities in central Henan Province are divided into three categories, which correspond to three different risk grades, respectively. With respect to different drought risk areas, corresponding countermeasures and suggestions are proposed. Practical implications This paper provides a practical and effective new method for the hazard assessment on drought disaster. Meanwhile, these countermeasures and suggestions can help policy makers to improve the efficiency of drought resistance work and reduce the losses caused by drought disasters in Henan Province. Originality/value This paper proposes a new GPIM which resolves the assessment problems of the uncertain systems with grey heterogeneous information, such as real numbers, interval grey numbers and three-parameter interval grey numbers. It not only expands the application scope of the grey incidence model, but also enriches the research of panel data.

The large-scale antenna array is one key technology for the next generation wireless communications. Both spectral-efficiency and energy-efficiency can be improved significantly with appropriate beamforming which focuses signals on the target receivers in a large-scale antenna system (LSAS). However, as the formed beams become narrower, inaccurate channel state information (CSI) can lead to severe system performance degradation. The transmission rate selection is also important to enable full system capacity. Therefore, it is worth investigating the joint rate and beamwidth adaptation for data transmission in the presence of CSI uncertainties. In this paper, the dynamic selection of the transmission rate and the beamwidth is first modeled as a stochastic multi-armed bandit (MAB) problem with constraints. We then propose an iterative algorithm based on the upper confidence bound to adapt the rate and beamwidth jointly to get high throughput while providing long-term QoS guarantees. Numerical results demonstrate the benefits of taking beamwidth adaptation into account and illustrate the superior performance of our proposed algorithm.

Background: Hydrophobins are small proteins secreted by filamentous fungi, which show a highly surface activity. Because of the signally self-assembling abilities and surface activities, hydrophobins were considered as candidates in many aspects, for example, stabilizing foams and emulsions in food products. Lentinus tuber-regium, known as tiger milk mushroom, is both an edible and medicinal sclerotium-producing mushroom. Up to now, the hydrophobins of L. tuber-regium have not been identified. Results: In this paper, a Class I hydrophobin gene, Ltr.hyd, was cloned from L. tuber-regium and expressed in the yeast-like cells of Tremella fuciformis mediated by Agrobacterium tumefaciens. The expression vector pGEH-GH was under the control of T. fuciformis glyceraldehyde-3-phosphate dehydrogenase gene (gpd) promoter. The integration of Ltr.hyd into the genome of T. fuciformis was confirmed by PCR, Southern blot, fluorescence observation and quantitative real-time PCR (qRT-PCR). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that recombinant hydrophobin rLtr.HYD with an expected molecular mass of 13 kDa was extracted. The yield of rLtr.HYD was 0.66 mg/g dry weight. The emulsifying activity of rLtr.HYD was better than the typical food emulsifiers sodium caseinate and Tween 20. Conclusions: We evaluated the emulsifying property of hydrophobin Ltr.HYD, which can be potentially used as a food emulsifier. Keywords: Agrobacterium tumefaciens, Emulsifier, Expression vector, Filamentous fungi, Gel electrophoresis, Glyceraldehyde-3-phosphate dehydrogenase, Heterogenous expression, Hydrophobin, Quantitative real-time PCR, Southern blot, Surface activity

A phonon merry-go-round Chirality is associated with the breaking of symmetry, often described as left- or right-handed behavior. Such asymmetry can be seen, for example, in the electronic responses of particular materials or the reactions between particular chemical species. Zhu et al. observed a chiral phonon mode in a monolayer of the transition metal dichalcogenide WSe 2 , detected spectroscopically as the circular dichroism of the phonon-assisted transition of holes. Phonon chirality could be used to control the electron-phonon coupling and/or the phonon-driven topological states of solids. Science , this issue p. 579

Background: Diabetic nephropathy (DN) is the most common and serious microvascular complication of diabetes. To date, the gold standard for identifying DN and nondiabetic renal disease (NDRD) is a renal biopsy; however, there is currently no reliable diagnostic marker to identify DN and NDRD in a noninvasive manner. This study aimed to investigate the different glycopatterns in urine specimens of DN patients and NDRD patients for a differential diagnosis. Methods: In total, 19 DN patients and 18 NDRD patients who underwent renal biopsies between March 2015 and March 2016 at the Chinese People’s Liberation Army General Hospital were enrolled in this study. A lectin microarray was used to investigate the glycopatterns in the urinary protein of the 37 patients. Ratio analysis and one-way analysis of variance were used to screen altered glycopatterns. Then, the altered glycopatterns between the DN and NDRD groups were verified by a urinary protein microarray among another 32 patients (15 with DN and 17 with NDRD), and receiver operating characteristic (ROC) curve analysis was used to determine the diagnostic value of the altered glycopatterns in differentiating DN and NDRD. Finally, lectin blotting was used to evaluate the altered glycosylation in protein level. Results: The result of lectin microarrays revealed that the relative abundance of the (β-1,4)-linked N-acetyl-D-glucosamine (GlcNAc) recognized by lectin Datura stramonium agglutinin (DSA) was significantly higher in urinary protein in DN patients than that in NDRD patients (fold change >1.50, P < 0.001). Subsequently, the results of urinary protein microarrays were consistent with lectin microarrays (P < 0.05). Furthermore, the ROC curve showed that glycopatterns could effectively distinguish DN from NDRD patients (area under the ROC curve = 0.94, P < 0.001). DSA lectin blotting showed that glycoproteins, with a molecular weight of approximately 50,000, demonstrated a difference in urine samples between DN patients and NDRD patients. Conclusions: The relative abundance of (β-1,4)-linked GlcNAc recognized by lectin DSA and urinary glycoprotein with a molecular weight of approximately 50,000 are significantly different between DN and NDRD patients, indicating that the glycopatterns could be used as potential biomarkers for a differential diagnosis. Key words: Diabetic Nephropathy; Glycopattern; Nondiabetic Renal Disease; Urinary Protein

Hanyu Zhu,1,* Qiuxia Han,2,* Dong Zhang,1 Yong Wang,1 Jing Gao,3 Xiaoli Yang,1 Wenjia Geng,4 Xiangmei Chen1 1Department of Nephrology, Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center of Kidney Diseases, Beijing Key Laboratory of Kidney Disease, Beijing, China; 2Department of Nephrology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou,China; 3Department of Clinical Biochemistry, Chinese PLA General Hospital, Beijing, China; 4Department of Nephrology, Guangdong Provincial Hospital of Chinese Medicine, Guangzhou, China *These authors contributed equally to this work Background: Membranous nephropathy (MN) represents a distinct glomerular disease which has been considered as a major cause of nephrotic syndrome (NS) in adults. Evidences show that the clinicopathological features of MN are various among MN cases. This study aimed to summarize and analyze the clinicopathological features of patients with MN.Methods: A total of 231 MN patients were recruited in this study. Their clinical and pathological features were collected and analyzed according to their age, gender, pathological stages, and anti-phospholipase A2 receptor (anti-PLA2R) antibodies tests.Results: Among the 231 MN cases, the ratio of male to female was 1.47 and the mean age was 47.43±14.32 years. Altogether, 163 (70.6%) cases were positive for NS. Their serum antiPLA2R, body mass index, total cholesterol, triglyceride, low density lipoprotein cholesterol, D2, IgA, and IgE were increased, but IgG was decreased. The majority of the patients were middle aged and old aged. In addition, the pathological stage was significantly correlated with gender (P=0.038), creatinine, (P=0.021) and IgE (P=0.003). A total of 74.9% MN patients were found to be positive for anti-PLA2R antibodies, and they were more likely to have abnormal serum indices.Conclusion: The major clinicopathological characteristics of MN patients are summarized in this study. Male and elder MN cases are likely to have rapid disease progression. Advanced pathological stages and being positive for anti-PLA2R antibodies may be potential indicators for disease activity of MN. Keywords: pathological features, clinical manifestation, membranous nephropathy

Background: Type 2 diabetes (T2DM) patients are susceptible to Helicobacter pylori (HP), and it has been reported that the occurrence of proteinuria is associated with HP infection in T2DM patients; however, this view remains controversial. This meta-analysis aimed to explore the association between HP infection and the occurrence of proteinuria in T2DM patients. In addition, we hope to provide some recommendations to readers in clinical or related fields. Methods: Our meta-analysis was conducted with the methodology of the Cochrane Collaboration. Search strategies were formulated by relevant professionals. Case–control studies that compared the occurrence of proteinuria in T2DM patients with and without HP infection were involved in our meta-analysis. Relevant English or Chinese studies were searched on online databases before 2018, including PubMed, the Cochrane library, Medline, Google Scholar, the China National Infrastructure, and Wanfang database. The search strategies were "diabetic proteinuria, diabetic microalbuminuria, diabetic albuminuria, diabetic kidney disease, diabetic renal dysfunction, diabetic renal disease, diabetic nephropathy, diabetic complications, and diabetic mellitus, combined with HP." The quality of these involved articles was separately assessed by two investigators using the Newcastle–Ottawa Scale (NOS). Odds ratios (ORs) and associated 95% confidence intervals (CIs) were extracted and pooled using fixed-effects models. Results: Seven studies involving 1029 participants were included. The quality of these seven articles was all above five stars as assessed by NOS, and there was no significant publication bias in our meta-analysis. We found that T2DM patients with HP infection had a 2.00 times higher risk of the occurrence of proteinuria than patients without HP infection (OR: 2.00, 95% CI: 1.48–2.69). Conclusions: Our analysis showed that HP infection was associated with the occurrence of proteinuria in T2DM patients. HP radical surgery might be a therapeutic option for protecting kidney function in patients with T2DM. Key words: Helicobacter pylori; Kidney; Meta-Analysis; Proteinuria; Type 2 Diabetes

With limited current biomass utilization as a renewable resource, it is important to develop a method to convert biomass into materials to replace fossil fuel products. In this article, lignin and carbohydrate derived monomers, including 4-methylcatechol, 5-hydroxymethylfurfural (HMF), and furfural, were used to prepare bisphenol–furan type polyphenols. Epoxy networks were synthesized from different polyphenol monomers via glycidylation and curing steps under identical reaction conditions. The structures of bisphenol–furan trinuclear compounds, epoxide precursors, and cured epoxy polymer networks were characterized by nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FTIR) and high resolution mass spectrometry (MS). Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA) were conducted to test the thermo-mechanical properties of the resulting networks. These polymer materials exhibited an excellent glassy modulus (9.6 GPa), glass transition temperature (Tg) (110 °C), and thermal stability. The density and water absorption of the materials were measured. This work provides synthesis routes to highly bio-based epoxy thermosets, which paves the way towards preparing moldable polymers from wood via biorefinery products.

Background: Diabetes mellitus (DM) has become the leading cause of chronic kidney disease (CKD). Nondiabetic renal diseases (NDRDs) have different clinicopathological features and prognosis from those of diabetic nephropathy. Our study sought to analyze the clinical and pathological features of NDRDs, in different age groups through a cross-sectional study. Methods: All patients with type 2 DM at our center who underwent renal biopsy between March 1997 and March 2017 were screened and divided into three groups by age: Group 1 (youth group), 18–44 years old; Group 2 (middle-aged group), 45–59 years old; and Group 3 (elderly group), ≥60 years old. We analyzed the clinicopathological data and risk factors by univariate and multivariate logistic regression for NDRD of the patients to identify the features of NDRD in different age groups. Results: We included 982 patients in the final analysis. Patients with NDRD accounted for 64.4% of all patients. IgA nephropathy (IgAN) was the most common pathological pattern in young patients with NDRD, accounting for 26.3%. In the middle-aged group, the two most common pathological patterns were IgAN and membranous nephropathy. Membranous nephropathy was the most common pathological pattern in elderly patients with NDRD, accounting for 29.3%. Consistent with pathological features, glomerular hematuria is a risk factor for NDRD in Group 1 (odds ratio [OR], 26.514; 95% confidence interval [CI], 2.503–280.910; P = 0.006). On the other hand, rapidly increasing proteinuria or nephrotic syndrome is a risk factor for NDRD in Group 2 (OR, 5.921; 95% CI, 2.061–17.013; P = 0.001) and Group 3 (OR, 90.409; 95% CI, 6.198–1318.826; P = 0.001). Conclusions: This single-center study showed that the proportion and composition of NDRD differ among different age groups. Consistent with pathological features, some clinical indices such as hematuria and proteinuria showed different features among different age groups. Key words: Age; Nondiabetic Renal Disease; Type 2 Diabetic Nephropathy

In the production of potassium sulfate by ammonium sulfate, the purity of potassium sulfate product is relatively low due to the presence of potassium sulfate and ammonium sulfate solid solution. The microstructure of mixed aqueous solution of potassium sulfate and ammonium sulfate have been studied by X-ray diffraction, Raman spectroscopy and molecular dynamics simulation. And the molality of SO42− in the solution remained unchanged, and the molality of K+ and NH4+ were changed respectively. Reduced structure function [F(Q)], reduced pair distribution function [G(r)], excess Raman spectroscopy, radial distribution function (RDF), and structure of hydrogen bond network were obtained. With the decrease of K+ concentration and the increase of NH4+ concentration, a variety of new ion contact pairs were formed in the solution. The original hydrogen bond network is disrupted, and the cations would rebuild the hydrogen bond in the solution. When the NH4+ replaces the K+, the destruction to the hydrogen bond network is reduced. The addition of NH4+ might weaken the interaction between water molecules and anions, and exceed a certain critical concentration of 0.8 mol·L-1, NH4+ could promote the interaction between water molecules and anions. Moreover, the experimental results are in good agreement with the simulation results. This article provides certain theoretical guidance for its separation by studying the microstructure of its mixed solution.

Energy Internet (EI) is an important way to solve the problem of clean utilization and effective management of energy. The features of EI , such as distributed autonomy and fusion of electric power and information, make its underlying subnet – Energy Local Area Network (ELAN) face greater risks and challenges of multiple devices, heterogeneous standards and real-time interaction in operation. Therefore, it is quite worth for the scientific and orderly development of the EI to study the traditional and new risks during the operation of the ELAN and simulate the transmission and evolution of risks between information and electricity. This article selects the risk of cyber attacks and discusses it based on a power supply station area in Beijing by building a cellular automaton model for risk transmission simulation. First, it constructs the cell architecture and conversion rules of the ELAN, set the information cell infection and defense mode and explains the power cell dispatching and shutdown mechanism. Secondly, the case station area is topologically transformed into a ”binary dependent” adjacent cellular network, and the simulation parameters are set. Finally, it simulates the risk transmission situation with different attack and defense strategies (A–D), different node self-healing rates β and different power over-limit thresholds γ . The simulation result shows the capability of ELAN to resist the transmission of risks across space will be significantly improved by protecting high-level nodes, improving the self-healing ability of information nodes and enhancing the callable power redundancy of autonomous units.

Monolayers of transition-metal dichalcogenides (TMDs) exhibit numerous crystal phases with distinct structures, symmetries and physical properties. Exploring the physics of transitions between these different structural phases in two dimensions may provide a means of switching material properties, with implications for potential applications. Structural phase transitions in TMDs have so far been induced by thermal or chemical means; purely electrostatic control over crystal phases through electrostatic doping was recently proposed as a theoretical possibility, but has not yet been realized. Here we report the experimental demonstration of an electrostatic-doping-driven phase transition between the hexagonal and monoclinic phases of monolayer molybdenum ditelluride (MoTe2). We find that the phase transition shows a hysteretic loop in Raman spectra, and can be reversed by increasing or decreasing the gate voltage. We also combine second-harmonic generation spectroscopy with polarization-resolved Raman spectroscopy to show that the induced monoclinic phase preserves the crystal orientation of the original hexagonal phase. Moreover, this structural phase transition occurs simultaneously across the whole sample. This electrostatic-doping control of structural phase transition opens up new possibilities for developing phase-change devices based on atomically thin membranes.

The products of fast pyrolysis that first leave the hot pyrolysis surface were identified for three G-lignin model compounds, a trimer, a tetramer and a synthetic polymer, all containing β-O-4 linkages, by using a very fast heating pyrolysis probe coupled with a linear quadrupole ion trap mass spectrometer or a linear quadrupole ion trap coupled with an orbitrap detector. High-resolution measurements were used to determine the elemental compositions of the deprotonated pyrolysis products. Their structures were examined using collision-activated dissociation experiments and via comparison to the dissociation reactions of ionized authentic compounds. The initial pyrolysis products for all model compounds range from monomers to tetramers. Even for the polymer, no products larger than tetramers were observed. None of the products were radicals. The observed trimers and tetramers were formed directly from the intact model compounds rather than from repolymerization of initially formed monomers. Both the observed product distributions and quantum chemical calculations suggest that the mechanism(s) of the major reactions occurring under the conditions employed here are Maccoll and/or retro-ene eliminations rather than radical reactions. Based on a comparison of the behavior of the smaller β-O-4 model compounds to the synthetic β-O-4 lignin polymer, the smaller model compounds appear to be good surrogates for further studies of the mechanisms of fast pyrolysis of lignin.

Structural symmetry-breaking plays a crucial role in determining the electronic band structures of two-dimensional materials. Tremendous efforts have been devoted to breaking the in-plane symmetry of graphene with electric fields on AB-stacked bilayers or stacked van der Waals heterostructures. In contrast, transition metal dichalcogenide monolayers are semiconductors with intrinsic in-plane asymmetry, leading to direct electronic bandgaps, distinctive optical properties and great potential in optoelectronics. Apart from their in-plane inversion asymmetry, an additional degree of freedom allowing spin manipulation can be induced by breaking the out-of-plane mirror symmetry with external electric fields or, as theoretically proposed, with an asymmetric out-of-plane structural configuration. Here, we report a synthetic strategy to grow Janus monolayers of transition metal dichalcogenides breaking the out-of-plane structural symmetry. In particular, based on a MoS2 monolayer, we fully replace the top-layer S with Se atoms. We confirm the Janus structure of MoSSe directly by means of scanning transmission electron microscopy and energy-dependent X-ray photoelectron spectroscopy, and prove the existence of vertical dipoles by second harmonic generation and piezoresponse force microscopy measurements.

Unusual cis-oxidative addition of methyltrioxorhenium (MTO) to [PtMe2(bpy)], (bpy = 2,2′-bipyridine) (1) is described. Addition of MTO to 1 first gives the Lewis acid–base adduct [(bpy)Me2Pt–Re(Me)(O)3] (2) and subsequently affords the oxidative addition product [(bpy)Me3PtReO3] (3). All complexes 1, MTO, 2, and 3 are in equilibrium in solution. The structure of 2 was confirmed by X-ray crystallography, and its dissociation constant in solution is 0.87 M. The structure of 3 was confirmed by extended X-ray absorption fine structure and X-ray absorption near-edge structure in tandem with one- and two-dimensional NMR spectroscopy augmented by deuterium and 13C isotope-labeling studies. Kinetics of formation of compound 3 revealed saturation kinetics dependence on [MTO] and first-order in [Pt], complying with prior equilibrium formation of 2 with oxidative addition of Me–Re being the rate-determining step. Exposure of 3 to molecular oxygen or air resulted in the insertion of an oxygen atom into the platinum–r...

This study investigated the diagnostic value of 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC) contents of human leucocyte antigen (HLA)-B and HLA-DQB1 in anti-tuberculosis drug-induced liver injury (ADLI). In total, 110 ADLI patients and 120 patients without ADLI controls were enrolled. Enzyme-linked immunosorbent assay (ELISA) was used to detect the 5-mC and 5-hmC content in DNA from peripheral blood leucocytes. The univariate analysis showed that smoking, drinking, and 5-mC and 5-hmC content of HLA-B and HLA-DQB1 were significantly associated with ADLI. After adjusting for drinking and smoking, we found that 5-mC content of HLA-B and HLA-DQB1 were associated with ADLI (odds ratio [OR] = 0.251 and 0.347, respectively) and 5-hmC contents of HLA-B and HLA-DQB1 were also associated with ADLI (OR = 1.848 and 4.705, respectively). Receiver operating characteristic (ROC) analysis indicated that the 5-hmC contents of both HLA-B and HLA-DQB1 were more clinically significant than the 5-mC contents were. The combined 5-hmC level of HLA-B and HLA-DQB1 was the best diagnostic biomarker for ADLI, with the highest areas under the curve (AUC) for 0.953, sensitivity for 0.900 and specificity for 0.875. Therefore, combined 5-hmC levels of HLA-B and HLA-DQB1 could be significant evidence for diagnosis of ADLI.

Background No studies have examined the practicality of the Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiological Collaboration (CKD-EPI) and Berlin Initiative Study 1 (BIS1) equations for the estimated glomerular filtration rate (eGFR) in a large sample of centenarians. We aim to investigate the differences among the equations and suggest the most suitable equation for centenarians and near-centenarians. Methods A total of 966 centenarians and 787 near-centenarians were enrolled, and the eGFR was calculated using the three equations mentioned above. Agreement among the equations was investigated with the κ statistic and Bland–Altman plots. Sources of discrepancy were investigated using a partial correlation analysis. Results The three equations for assessing eGFR are not considered interchangeable in centenarians and near-centenarians. Δ(MDRD, CKD-EPI) and Δ(MDRD, BIS1) increased with age, but Δ(CKD-EPI, BIS1) was relatively stable with age. Δ(MDRD, CKD-EPI) and Δ(MDRD, BIS1) were considerable in subjects with Scr levels less than 0.7 mg/dL and decreased with the Scr level. A considerable difference between CKD-EPI and BIS1 was observed for participants with Scr levels ranging from 0.5 to 1.5 mg/dL. This difference increased with Scr levels ranging from 0.5 to 0.7 mg/dL, was relatively stable for Scr levels ranging from 0.7 to 0.9 mg/dL, and decreased with Scr levels ranging from 0.9 to 1.5 mg/dL. The differences in the three comparisons were all greater in women than in men (p Conclusions We tend to suggest the MDRD equation to calculate the glomerular filtration rate (GFR) in elderly individuals >95 years old who have no risk factors for cardiovascular disease; the BIS1 equation to calculate the eGFR for elderly individuals younger than 94 years old who have risk factors for cardiovascular disease; the CKD-EPI equation to calculate the eGFR of elderly individuals with Scr levels greater than 1.5 mg/dL; and the BIS1 equation to calculate the eGFR of older women with Scr levels less than 0.7 mg/dL.

Chirality characterizes an object that is not identical to its mirror image. In condensed matter physics, Fermions have been demonstrated to obtain chirality through structural and time-reversal symmetry breaking. These systems display unconventional electronic transport phenomena such as the quantum Hall effect and Weyl semimetals. However, for bosonic collective excitations in atomic lattices, chirality was only theoretically predicted and has never been observed. We experimentally show that phonons can exhibit intrinsic chirality in monolayer tungsten diselenide, whose lattice breaks the inversion symmetry and enables inequivalent electronic K and -K valley states. The time-reversal symmetry is also broken when we selectively excite the valley polarized holes by circularly polarized light. Brillouin-zone-boundary phonons are then optically created by the indirect infrared absorption through the hole-phonon interactions. The unidirectional intervalley transfer of holes ensures that only the phonon modes in one valley are excited. We found that such photons are chiral through the transient infrared circular dichroism, which proves the valley phonons responsible to the indirect absorption has non-zero pseudo-angular momentum. From the spectrum we further deduce the energy transferred to the phonons that agrees with both the first principle calculation and the double-resonance Raman spectroscopy. The chiral phonons have significant implications for electron-phonon coupling in solids, lattice-driven topological states, and energy efficient information processing.

Background. Mesangial cells play a prominent role in the development of inflammatory diseases and autoimmune disorders of the kidney. Mesangial cells perform the essential functions of helping to ensure that the glomerular structure is stable and regulating capillary flow, and activated mesangial cells acquire proinflammatory activities. We investigated whether activated mesangial cells display immune properties and control the development of T cell immunity. Methods. Flow cytometry analysis was used to study the expression of antigen-presenting cell surface markers and costimulatory molecules in mesangial cells. CD4+ T cell activation induced by mesangial cells was detected in terms of T cell proliferation and cytokine production. Results. IFN-γ-treated mesangial cells express membrane proteins involved in antigen presentation and T cell activation, including MHC-II, ICAM-1, CD40, and CD80. This finding suggests that activated mesangial cells can take up and present antigenic peptides to initiate CD4+ T cell responses and thus act as nonprofessional antigen-presenting cells. Polarization of naïve CD4+ T cells (Th0 cells) towards the Th1 phenotype was induced by coculture with activated mesangial cells, and the resulting Th1 cells showed increased mRNA and protein expression of inflammation-associated genes. Conclusion. Mesangial cells can present antigen and modulate CD4+ T lymphocyte proliferation and differentiation. Interactions between mesangial cells and T cells are essential for sustaining the inflammatory response in a variety of glomerulonephritides. Therefore, mesangial cells might participate in immune function in the kidney.

Massive multiple-input multiple-output (MIMO) can increase the spectral efficiency. Besides, it can provide accurate localization. In some applications, e.g. autonomous driving, user behavior such as velocity and moving direction needs to be detected in addition to the position. In this paper, we propose Massive MIMO based Detection and Ranging (MIDAR) to offer a solution for joint localization and behavior recognition based on the power spectrum in multiple domains. An angle-delay-Doppler power spectrum (ADD-PS) is extracted from a mass of channel state information (CSI) as the fingerprint of a particular position with a certain behavior. By matching this fingerprint to a big data set of pre-collected reference points, we can obtain improved localization performance and detect the user behavior at the same time. In order to take full advantage of the geometrical structure of the multi-dimensional ADD-PS, algorithms in tensor analysis are considered and a chordal distance based kernel (CDBK) method is exploited for the large-scale fingerprint matching. Numerical results corroborate the feasibility of MIDAR for joint localization and behavior recognition and demonstrate that the CDBK approach outperforms conventional matching schemes for massive MIMO based localization.

Pilot contamination mitigation in the uplink (UL) is an important problem to tackle in massive multiple-input multiple-output (MIMO). Existing researches only relied on the angle of arrival knowledge at the base station (BS). In this paper, we propose an enhanced pilot decontamination strategy using the angle of departure information at the user side. Since this information is contained in the Doppler power spectrum density (PSD), we first analyze the directional Doppler PSD (D-PSD) at a particular angle impinging on the BS. A closed-form expression of the D-PSD for an arbitrary angle distribution at the user side is provided and the spatial-wideband effect caused by the large number of antennas is also considered. We then present a method to mitigate the pilot contamination by exploiting the D-PSD. We further verify its effectiveness in offering more orthogonal pilots and reducing channel estimation errors compared with our previous works. Simulations show the proposed scheme can serve as one additional decontamination mechanism for the UL pilots in massive MIMO.

A water deficit during the grain-filling stage increases the frequency of yield loss in maize (Zea mays L.). Abscisic acid (ABA) plays a regulatory role in many stages of plant growth, however, its effects on sucrose-metabolizing enzyme activities under stress are poorly understood. The activities of cell-wall-bound acid invertase, vacuolar invertase, cytoplasmic invertase, and sucrose synthase decreased continuously under drought stress, whereas ABA treatment partially restored these activities. In addition, the increase and development of sucrose content under drought stress were related to invertase activity. Up-regulation of the activities and gene expression of cell-wall-bound acid invertase and vacuolar invertase with ABA treatment contributed to the increase in the number of rows and number of grains per row. Furthermore, ABA inhibited the increase in the length of the bald tip. Compared with the control group, water stress significantly reduced the yield index, with the lowest yield index on the 10th day of stress. These results suggest that the increase in ABA-induced sucrose-metabolizing enzyme activity might be an effective mechanism to improve maize drought resistance at the grain-filling stage.

Next-generation electronics calls for new materials beyond silicon, aiming at increased functionality, performance and scaling in integrated circuits. In this respect, two-dimensional gapless graphene and semiconducting transition-metal dichalcogenides have emerged as promising candidates due to their atomic thickness and chemical stability. However, difficulties with precise spatial control during their assembly currently impede actual integration into devices. Here, we report on the large-scale, spatially controlled synthesis of heterostructures made of single-layer semiconducting molybdenum disulfide contacting conductive graphene. Transmission electron microscopy studies reveal that the single-layer molybdenum disulfide nucleates at the graphene edges. We demonstrate that such chemically assembled atomic transistors exhibit high transconductance (10 µS), on–off ratio (∼106) and mobility (∼17 cm2 V−1 s−1). The precise site selectivity from atomically thin conducting and semiconducting crystals enables us to exploit these heterostructures to assemble two-dimensional logic circuits, such as an NMOS inverter with high voltage gain (up to 70). Large-scale electronic circuits can be assembled via the spatially controlled synthesis of heterostructures made of single-layer molybdenum disulfide contacting graphene.

Rationale The oxidation of sulfur atoms is an important biotransformation pathway for many sulfur-containing drugs. In order to rapidly identify the sulfone functionality in drug metabolites, a tandem mass spectrometric method based on ion–molecule reactions was developed. Methods A phosphorus-containing reagent, trimethyl phosphite (TMP), was allowed to react with protonated analytes with various functionalities in a linear quadrupole ion trap mass spectrometer. The reaction products and reaction efficiencies were measured. Results Only protonated sulfone model compounds were found to react with TMP to form a characteristic [TMP adduct–MeOH] product ion. All other protonated compounds investigated, with functionalities such as sulfoxide, N-oxide, hydroxylamino, keto, carboxylic acid, and aliphatic and aromatic amino, only react with TMP via proton transfer and/or addition. The specificity of the reaction was further demonstrated by using a sulfoxide-containing anti-inflammatory drug, sulindac, as well as its metabolite sulindac sulfone. Conclusions A method based on functional group-selective ion–molecule reactions in a linear quadrupole ion trap mass spectrometer has been demonstrated for the identification of the sulfone functionality in protonated analytes. A characteristic [TMP adduct–MeOH] product ion was only formed for the protonated sulfone analytes. The applicability of the TMP reagent in identifying sulfone functionalities in drug metabolites was also demonstrated. Copyright © 2016 John Wiley & Sons, Ltd.

To gain insights into dimorphism, cell wall polysaccharides from Tremella fuciformis strains were obtained from alkali-extracted water-soluble fractions PTF-M38 (from the mycelial form), PTF-Y3 and PTF-Y8 (from the yeast form) of T. fuciformis strains were used to gain some insights into dimorphism study. Their chemical properties and structural features were investigated using gel permeation chromatography, gas chromatography, UV and IR spectrophotometry and Congo red binding reactions. The results indicated that the backbones of PTF-M38, PTF-Y3 and PTF-Y8 were configured with α-linkages with average molecular weights of 1.24, 1.08, and 1.19 kDa, respectively. PTF-M38 was mainly composed of xylose, mannose, glucose, and galactose in a ratio of 1:1.47:0.48:0.34, while PTF-Y3 and PTF-Y8 were mainly composed of xylose, mannose and glucose in a ratio of 1:1.65:4.06 and 1:1.21:0.44, respectively. The sugar profiles of PTF-M38, PTF-Y3 and PTF-Y8 were also established for further comparison. These profiles showed that all three polysaccharides contained the same sugars but in different ratios, and the carbon sources (xylose, mannose, glucose, and galactose) affected the sugar ratios within the polysaccharides.

Electrically controlling the flow of charge carriers is the foundation of modern electronics. By accessing the extra spin degree of freedom (DOF) in electronics, spintronics allows for information processes such as magnetoresistive random-access memory. Recently, atomic membranes of transition metal dichalcogenides (TMDCs) were found to support unequal and distinguishable carrier distribution in different crystal momentum valleys. This valley polarization of carriers enables a new DOF for information processing. A variety of valleytronic devices such as valley filters and valves have been proposed, and optical valley excitation has been observed. However, to realize its potential in electronics it is necessary to electrically control the valley DOF, which has so far remained a significant challenge. Here, we experimentally demonstrate the electrical generation and control of valley polarization. This is achieved through spin injection via a diluted ferromagnetic semiconductor and measured through the helicity of the electroluminescence due to the spin-valley locking in TMDC monolayers. We also report a new scheme of electronic devices that combine both the spin and valley DOFs. Such direct electrical generation and control of valley carriers opens up new dimensions in utilizing both the spin and valley DOFs for next-generation electronics and computing.

Lignin as a polymer of monomeric aromatic compounds retains great potential to be a source for liquid fuels and valuable chemicals. However, lignin from biomass has been traditionally treated as a waste byproduct and in most applications burned for its heat value. In this work, we report the catalytic conversion of lignin in Miscanthus into aromatic products by using earth-abundant Ni catalyst supported on activated carbon, under relatively mild conditions. The special ferulate linkage in grasses gives methyl ferulate ester and its derivatives, which were not observed for wood biomass substrates. By modification of the reaction conditions, saturated or unsaturated branched products can be obtained selectively. Optimal conditions give over 68% yield of select aromatic products from lignin. Furthermore, after lignin depolymerization and upgrading, the carbohydrates of miscanthus were recovered as a solid residue, which upon treatment with iron chloride produced useful platform chemicals (furfurals and levulinic acid). On the basis of our study, all three major components of biomass (lignin, cellulose and hemicellulose) are effectively utilized, with an overall 55% conversion of total accessible biomass into high value chemicals with 98% mass balance.

Background Persistent proteinuria is an important factor contributing to the progression of diabetic nephropathy. The present randomized double-blind placebo-controlled multicenter clinical study evaluated the efficacy and safety of telmisartan combined with the antioxidant probucol in reducing urinary protein levels in patients with type 2 diabetes (T2D). Methods Patients with T2D and 24-h proteinuria 0.5–3 g were enrolled in the study and randomly assigned to one of two groups: a telmisartan or a probucol + telmisartan group. Both groups were given telmisartan 80 mg q.d. for 48 weeks. The probucol + telmisartan group was given probucol 500 mg b.i.d. for the first 24 weeks, with the dosage then reduced to 250 mg b.i.d. for the remaining 24 weeks. The telmisartan group was given probucol placebo. Results In all, 160 patients were enrolled in the present study. The 24-h proteinuria levels were significantly reduced in the probucol + telmisartan compared with telmisartan group. For patients with baseline 24-h proteinuria levels

Lentinus tuber-regium is a sclerotium-forming basidiomycetous mushroom. It has increasingly aroused people's attention for its medicinal effects. In this study, we investigated the applicability of the Agrobacterium tume-faciens-mediated transformation (ATMT) method in L. tuber-regium. A. tumefaciens strain GV 3101 harboring the vector pPEH was used to transform the mycelium of L. tuber-regium strain ACCC50657. The genes for hygromycin B phosphotransferase (hph) and enhanced green fluorescent protein (egfp) under the control of the glyceraldehyde-3-phosphate dehydrogenase (gpd) gene promoter of Pleurotus ostreatus were employed as the selection marker and reporter gene, respectively. The optimal cocultivation temperature and time for transformation were 3 days and 4 days at 25°C and 20°C, respectively. Southern blot analysis showed the variation in the copy number and position of hph, which indicated random integration of hph. Polymerase chain reaction and fluorescence microscopy indicated that the P. ostreatus gpd promoter can drive the fused hph-egfp gene expression in L. tuber-regium. This is the first report that the ATMT method was successfully applied to L. tuber-regium. This reliable and efficient transformation method could be a powerful tool for strain genetic improvement and gene function study in L. tuber-regium.

Diabetic nephropathy (DN) and nondiabetic renal disease (NDRD) are two major categories of renal diseases in diabetes mellitus patients. The clinical differentiation among them is usually not so clear and effective. In this study, sera from DN and NDRD patients were collected, and glycan profiles of serum proteins from DN and NDRD patients were investigated and compared by using lectin microarray and lectin blot. Then, altered glycoproteins were enriched by lectin coupled magnetic particle conjugate and characterized by LC-MS/MS. We found significant change in glycan patterns between DN and NDRD patients. In particular, the relative abundance of the glycopattern of Galβ1-3GalNAc which was identified by BPL (Bauhinia purpurea lectin) was significantly decreased in DN patients compared to four types of NDRD patients (p < 0.05). Moreover, BPL blotting indicated that the proteins with a molecular weight of about 53 kDa exhibited low staining signal in DN compared to all NDRD groups, which was consistent with results of lectin microarrays. After enriching by BPL and identification by LC-MS/MS, a total of 235 and 258 proteins were characterized from NDRD and DN respectively. Among these, the relative abundance of 12 isolated serum proteins exhibited significantly alteration between DN and NDRD (p < 0.05). Our findings indicated not only the relative abundance of Galβ1-3GalNAc on serum proteins but also certain glycoproteins modified with this glycopattern showed a difference between DN and NDRD patients. This suggested that the analysis of this alteration by using urine specimens may constitute an additional valuable diagnostic tool for differentiating DN and NDRD with a non-invasive method.

In time-division duplexing (TDD) systems, massive multiple-input multiple-output (MIMO) relies on the channel reciprocity to obtain the downlink (DL) channel state information (CSI) with the acquired uplink (UL) CSI at the base station (BS). However, the mismatches in the radio frequency (RF) analog circuits among different antennas at the BS break the end-to-end UL and DL channel reciprocity. To avoid the severe performance degradation with massive MIMO, it is necessary to calibrate all the ℳ antennas at the BS to restore the end-to-end UL/DL channel reciprocity. In this paper, we examine the internal self-calibration scheme where different BS antennas are interconnected via hardware transmission lines. First, we study the resulting calibration performance for an arbitrary interconnection strategy. Next, we obtain closed-form Cramer-Rao lower bound (CRLB) expressions for each interconnection strategy at the BS with only $(M-1)$ transmission lines. Basing on the derived results, we further prove that the star interconnection strategy is optimal for internal self-calibration due to its lowest CRLB. Numerical simulation results corroborate our theoretical analyses and results.

Out-of-plane ferroelectricity with a high transition temperature in ultrathin films is important for the exploration of new domain physics and scaling down of memory devices. However, depolarizing electrostatic fields and interfacial chemical bonds can destroy this long-range polar order at two-dimensional (2D) limit. Here we report the experimental discovery of the locking between out-of-plane dipoles and in-plane lattice asymmetry in atomically thin In_{2}Se_{3} crystals, a new stabilization mechanism leading to our observation of intrinsic 2D out-of-plane ferroelectricity. Through second harmonic generation spectroscopy and piezoresponse force microscopy, we found switching of out-of-plane electric polarization requires a flip of nonlinear optical polarization that corresponds to the inversion of in-plane lattice orientation. The polar order shows a very high transition temperature (∼700 K) without the assistance of extrinsic screening. This finding of intrinsic 2D ferroelectricity resulting from dipole locking opens up possibilities to explore 2D multiferroic physics and develop ultrahigh density memory devices.

In time-division duplexing (TDD) systems, massive multiple-input multiple-output (MIMO) relies on the channel reciprocity to obtain the downlink (DL) channel state information (CSI) with the acquired uplink (UL) CSI at the base station (BS). However, the mismatches in the radio frequency (RF) analog circuits at different antennas at the BS break the end-to-end UL and DL channel reciprocity. To restore the channel reciprocity, it is necessary to calibrate all the antennas at the BS. This paper addresses the interconnection strategy for the internal self-calibration at the BS where different antennas are interconnected via hardware transmission lines. Specifically, the paper reveals the optimality of the star interconnection and the daisy chain interconnection respectively. From the results, we see the star interconnection is the optimal interconnection strategy when the BS are given the same number of measurements. On the other hand, the daisy chain interconnection outperforms the star interconnection when the same amount of time resources are consumed. Numerical results corroborate our theoretical analyses., 5 pages, 5 figures, conference

The chiral phonons at the corners of the Brillouin zone in inversion asymmetric 2D atomic lattices were revealed by the circular-polarization selection rules and the spectrum of the indirect intervalence band transition.

A laser is made from the two-dimensional material WS2 by embedding it into a microdisk resonator.

Mimivirus was initially identified as a bacterium because its dense, 125-nm-long fibers stained Gram-positively. These fibers probably play a role during the infection of some host cells. The normal hosts of Mimivirus are unknown, but in the laboratory Mimivirus is usually propagated in amoeba. The structure of R135, a major component of the fibrous outer layer of Mimivirus, has been determined to 2-Å resolution. The protein's structure is similar to that of members of the glucose-methanol-choline oxidoreductase family, which have an N-terminal FAD binding domain and a C-terminal substrate recognition domain. The closest homolog to R135 is an aryl-alcohol oxidase that participates in lignin biodegradation of plant cell walls. Thus R135 might participate in the degradation of their normal hosts, including some lignin-containing algae.

Free-standing monolayers of MoS2 exhibit piezoelectric behaviour due to inversion symmetry breaking. Piezoelectricity allows precise and robust conversion between electricity and mechanical force, and arises from the broken inversion symmetry in the atomic structure1,2,3. Reducing the dimensionality of bulk materials has been suggested to enhance piezoelectricity4. However, when the thickness of a material approaches a single molecular layer, the large surface energy can cause piezoelectric structures to be thermodynamically unstable5. Transition-metal dichalcogenides can retain their atomic structures down to the single-layer limit without lattice reconstruction, even under ambient conditions6. Recent calculations have predicted the existence of piezoelectricity in these two-dimensional crystals due to their broken inversion symmetry7. Here, we report experimental evidence of piezoelectricity in a free-standing single layer of molybdenum disulphide (MoS2) and a measured piezoelectric coefficient of e11 = 2.9 × 10–10 C m−1. The measurement of the intrinsic piezoelectricity in such free-standing crystals is free from substrate effects such as doping and parasitic charges. We observed a finite and zero piezoelectric response in MoS2 in odd and even number of layers, respectively, in sharp contrast to bulk piezoelectric materials. This oscillation is due to the breaking and recovery of the inversion symmetry of the two-dimensional crystal. Through the angular dependence of electromechanical coupling, we determined the two-dimensional crystal orientation. The piezoelectricity discovered in this single molecular membrane promises new applications in low-power logic switches for computing and ultrasensitive biological sensors scaled down to a single atomic unit cell8,9.

In a time-division duplexing (TDD) system, the uplink (UL) and downlink (DL) channel reciprocity gets impaired due to the mismatches of the antenna radio frequency (RF) electronics. Meanwhile, in massive multiple-input multiple-output (MIMO), as the antenna elements are placed close to each other, the mutual coupling effects among the adjacent antennas also become pronounced. Different coupling matrices for transmission and reception also hurt the end-to-end UL/DL channel reciprocity. Aiming to restore the end-to-end channel reciprocity with a small amount of over-the-air (OTA) resources, we propose to estimate the gain mismatches of the RF electronics and the mutual coupling mismatches separately. Specifically, we rely on the pilot exchanges among the BS antennas and the symmetry of the antenna array to recover the transmit and receive gains of all the RF components. Unlike prior calibration works, our schemes can recover the off-diagonal elements in the calibration matrix as well. Our designs are also corroborated with numerical simulations.

We demonstrate non-volatile, n-type, back-gated, MoS$_{2}$ transistors, placed directly on an epitaxial grown, single crystalline, PbZr$_{0.2}$Ti$_{0.8}$O$_{3}$ (PZT) ferroelectric. The transistors show decent ON current (19 ${\mu}A/{\mu}$m), high on-off ratio (10$^{7}$), and a subthreshold swing of (SS ~ 92 mV/dec) with a 100 nm thick PZT layer as the back gate oxide. Importantly, the ferroelectric polarization can directly control the channel charge, showing a clear anti-clockwise hysteresis. We have selfconsistently confirmed the switching of the ferroelectric and corresponding change in channel current from a direct time-dependent measurement. Our results demonstrate that it is possible to obtain transistor operation directly on polar surfaces and therefore it should be possible to integrate 2D electronics with single crystalline functional oxides.