Latest insights into the global epidemiological features, screening, early diagnosis and prognosis prediction of esophageal squamous cell carcinoma.

As a highly invasive carcinoma, esophageal cancer (EC) was the eighth most prevalent malignancy and the sixth leading cause of cancer-related death worldwide in 2020. Esophageal squamous cell carcinoma (ESCC) is the major histological subtype of EC, and its incidence and mortality rates are decreasing globally. Due to the lack of specific early symptoms, ESCC patients are usually diagnosed with advanced-stage disease with a poor prognosis, and the incidence and mortality rates are still high in many countries, especially in China. Therefore, enormous challenges still exist in the management of ESCC, and novel strategies are urgently needed to further decrease the incidence and mortality rates of ESCC. Although the key molecular mechanisms underlying ESCC pathogenesis have not been fully elucidated, certain promising biomarkers are being investigated to facilitate clinical decision-making. With the advent and advancement of high-throughput technologies, such as genomics, proteomics and metabolomics, valuable biomarkers with high sensitivity, specificity and stability could be identified for ESCC. Herein, we aimed to determine the epidemiological features of ESCC in different regions of the world, especially in China, and focused on novel molecular biomarkers associated with ESCC screening, early diagnosis and prognosis prediction.

Open-Nanogap-Induced Strong Electromagnetic Enhancement in Au/AgAu Monolayer as a Stable and Uniform SERS Substrate for Ultrasensitive Detection.

Nanogap-based plasmonic metal nanocrystals have been applied in surface-enhanced Raman scattering detection, while the closed and insufficient electromagnetic fields as well as the nonreproducible Raman signal of the substrate greatly restrict the actual application. Herein, a highly uniform Au/AgAu monolayer with abundant nanogaps and huge electromagnetic enhancement is prepared, which shows ultrasensitive and reproducible SERS detection. Au/AgAu with an inner nanogap is first prepared based on Au nanotriangles, and the nanogap is opened from the three tips via a subsequent etching process. The open-gap Au/AgAu displays much higher SERS efficiency than Au and Au/AgAu with an inner nanogap on detecting crystal violet due to the open-gap induced electromagnetic enhancement and improved molecular absorption. Furthermore, the open-gap Au/AgAu monolayer is prepared via interfacial self-assembly, which shows further improved SERS due to the dense and strong hotspots in the nanocavities induced by the electromagnetic coupling between adjacent open gaps. The monolayer possesses excellent signal stability, uniformity, and reproducibility. The analytic enhancement factor and relative standard deviation reach to 2.12 × 108 and 4.65% on detecting crystal violet, respectively. Moreover, the monolayer achieves efficient detection of thiram in apple juice, biphenyl-4-thiol, 4-mercaptobenzoic, melamine, and a mixed solution of four different molecules, showing great promise in practical detection.

BJLD-CMI: a predictive circRNA-miRNA interactions model combining multi-angle feature information.

Increasing research findings suggest that circular RNA (circRNA) exerts a crucial function in the pathogenesis of complex human diseases by binding to miRNA. Identifying their potential interactions is of paramount importance for the diagnosis and treatment of diseases. However, long cycles, small scales, and time-consuming processes characterize previous biological wet experiments. Consequently, the use of an efficient computational model to forecast the interactions between circRNA and miRNA is gradually becoming mainstream. In this study, we present a new prediction model named BJLD-CMI. The model extracts circRNA sequence features and miRNA sequence features by applying Jaccard and Bert's method and organically integrates them to obtain CMI attribute features, and then uses the graph embedding method Line to extract CMI behavioral features based on the known circRNA-miRNA correlation graph information. And then we predict the potential circRNA-miRNA interactions by fusing the multi-angle feature information such as attribute and behavior through Autoencoder in Autoencoder Networks. BJLD-CMI attained 94.95% and 90.69% of the area under the ROC curve on the CMI-9589 and CMI-9905 datasets. When compared with existing models, the results indicate that BJLD-CMI exhibits the best overall competence. During the case study experiment, we conducted a PubMed literature search to confirm that out of the top 10 predicted CMIs, seven pairs did indeed exist. These results suggest that BJLD-CMI is an effective method for predicting interactions between circRNAs and miRNAs. It provides a valuable candidate for biological wet experiments and can reduce the burden of researchers.

[Simulation of Pollution Apportionment and Optimization of Control Methods in Watershed Scale: A Case Study of the Shun'an Watershed in Tongling City].

The protection of the Yangtze River is an important national strategy in China, but it faces many problems such as difficult water environment protection, unclear pollution sources, and low integration of measures. Aimed at addressing watershed scale multi-source pollution together with facing the bottleneck method, by combining research data analysis, mechanism model, and intelligent algorithm optimization, this study built the framework for accurate pollution apportionment, measures evaluation, and overall measure optimization. Shun'an watershed in Tongling City of Anhui Province was set as an example for the application. The results showed that the new method could accurately quantify the impacts of planting industry, rural life, livestock and poultry breeding, aquaculture, industrial sewage, and domestic sewage in the watershed and evaluate the overall effects of various measures. The multi-objective optimization algorithm provided a cooperative multi-source pollution control scheme with higher cost performance and better environmental benefit by comparing the cost effectiveness of various schemes systematically. The optimization scheme showed that total nitrogen could be reduced by 1274.24 t·a-1 in wet years, 855.24 t·a-1 in normal years, and 381.96 t·a-1 in dry years. Total phosphorus was reduced by 321.42 t·a-1 in wet years, 159.80 t·a-1 in normal years, and 42.93 t·a-1 in dry years, such that the water quality reached the surface class Ⅲ water quality standard. These research results can be extended to other watersheds and provide a method reference for water environment protection under the background of the high-quality development of watersheds.

Study on the Relationship Between Differentially Expressed Proteins in Breast Cancer and Lymph Node Metastasis.

INTRODUCTION: Lymph node metastasis is a cause of poor prognosis in breast cancer. Mass spectrometry-based proteomics aims to map the protein landscapes of biological samples and profile tumors more comprehensively. Here, proteomics was employed to identify differentially expressed proteins (DEPs) that were associated with lymph node metastasis. METHODS: Tandem mass tag (TMT) quantitative proteomic approaches were applied for extensive profiling of conditioned medium of MDA-MB-231 and MCF7 cell lines and serums of patients who did or did not have lymph node metastasis, and DEPs were analyzed by bioinformatics. Furthermore, potential secreted or membrane proteins MUC5AC, ITGB4, CTGF, EphA2, S100A4, PRDX2, and PRDX6 were selected for verification in 114 tissue microarray samples of breast cancer using the immunohistochemical method. The relevant data was analyzed and processed by independent sample t test, chi-square test, or Fisher's exact test using SPSS 22.0 software. RESULTS: In the conditioned medium of MDA-MB-231 cell lines, 154 proteins were upregulated, while 136 were downregulated compared to those of MCF7. In the serum of patients with breast cancer and lymph node metastasis, 17 proteins were upregulated, and 5 proteins were downregulated compared to those without lymph node metastasis. Furthermore, according to tissue verification, CTGF, EphA2, S100A4, and PRDX2 were associated with breast cancer lymph node metastasis. CONCLUSION: Our study provides a new perspective for the understanding of the role of DEPs (especially CTGF, EphA2, S100A4, and PRDX2) in the development and metastasis of breast cancer. They could become potential diagnostic and prognostic biomarkers and therapeutic targets.

Optimized electromagnetic enhancement and charge transfer in MXene/Au/Cu2O hybrids for achieving efficient SERS.

The rational optimization of the electromagnetic field enhancement and charge transfer in a Raman substrate is vital for achieving efficient surface-enhanced Raman scattering (SERS). Herein, a ternary plasmonic substrate, whose structure-adjustable Au nanotriangle/Cu2O hybrids are combined with two-dimensional Ti3C2Tx MXene ultrathin nanosheets, is prepared and used for efficient SERS detection of molecules. By controlling the growth of Cu2O on Au nanotriangles, Au/Cu2O hybrids with three tips exposed are prepared, which show much better SERS performance than bare Au and core-shell Au@Cu2O in detecting methylene blue (MB) under excitation at 785 nm due to the optimized electromagnetic field enhancement and charge transfer. Furthermore, the Au/Cu2O hybrids are transferred to the plasmonic Ti3C2Tx nanosheet, generating a further enhanced electromagnetic field around their interfaces. As a result, the MXene/Au/Cu2O hybrids present further improved SERS activity, and their analytical enhancement factor reaches 2.4 × 109 and the detection limit is as low as 10-12 M. The enhancement mechanism can be ascribed to the improved electric field enhancement around the Au tips and the interface between MXene and Au/Cu2O. Meanwhile, the multiple charge-transfer processes between Au, Cu2O, MXene, and MB also play an important role in improving the SERS signal.

Plasmon Coupling and Efficient Charge Transfer in Rough-Surfaced Au Nanotriangles/MXene Hybrids as an Ultrasensitive Surface-Enhanced Raman Scattering Platform.

The rational design of Raman substrate materials with prominent electromagnetic enhancement and charge transfer is quite important for surface-enhanced Raman scattering (SERS). Herein, an efficient SERS substrate based on two-dimensional ultrathin Ti3C2T x MXene and rough-surfaced Au nanotriangles (NTs) was successfully prepared for efficient detection of organic molecules due to the synthetic effect of an optimized electromagnetic field and charge transfer. Uniform Au NTs with tunable surface roughness were controllably prepared by selectively depositing of Au on the smooth Au NTs. Due to the large surface area, tunable plasmon resonance, and abundant hotspots on the planar surface, the modified Au NTs showed much better SERS performance than initial Au NTs. By combination of the rough-surfaced Au NTs with MXene, the Ti3C2T x /Au NT hybrids exhibited much better SERS performance than initial Au NTs and Au NTs with a rough surface. The detection limit is down to 10-12 M, and the analytical enhancement factors reach 3.6 × 109 (at 1174 cm-1) on detecting crystal violet excited at 785 nm. This is because the strong plasmon coupling between the in-plane resonance of Au NTs and transversal plasmon resonance of Ti3C2T x MXene around 785 nm can generate an intense interfacial electromagnetic field for amplifying SERS signals. Additionally, the efficient charge transfer between Au NTs, MXene, and molecules also plays an important role in enhancing the SERS performance. This work presents a new insight to develop high-performance SERS substrates based on plasmon.

Programmed death-ligand 1 expression in the tumour stroma of colorectal liver oligometastases and its association with prognosis after liver resection.

BACKGROUND: The clinical value of programmed death-ligand 1 (PD-L1) expression in colorectal liver oligometastases (CLOs) remains undefined. This study aimed to detect PD-L1 in the microenvironment of CLOs and determine its association with patient prognosis. METHODS: We collected 126 liver-resection specimens from CLO patients who underwent curative liver resection between June 1999 and December 2016. Immunohistochemistry (IHC) was performed to assess PD-L1 expression in paraffin-embedded specimens. Overall survival (OS) and recurrence-free survival (RFS) were analysed using the Kaplan-Meier method and log-rank test. RESULTS: PD-L1 was mainly expressed in the stroma of liver oligometastases. Patients with high PD-L1 expression had a higher proportion of clinical-risk scores (CRSs) of 2-4 (67.7% vs 40.4%; P = 0.004). With a median 58-month follow-up, patients with high PD-L1 expression had a significantly lower 3-year OS rate (65.5% vs 92.7%; P = 0.001) and 3-year RFS rate (34.7% vs 83.8%; P < 0.001) than patients with low PD-L1 expression. Multivariate Cox analysis demonstrated that high PD-L1 expression (hazard ratio [HR] = 3.581; 95% confidence interval [CI] 2.301-9.972; P = 0.015), CRS 2-4 (HR = 6.960; 95% CI 1.135-42.689; P = 0.036) and increased preoperative CA19-9 (HR = 2.843; 95% CI 1.229-6.576; P = 0.015) were independent risk factors for OS. High PD-L1 expression (HR = 4.815; 95% CI 2.139-10.837; P < 0.001) and lymph-node metastasis (HR = 2.115; 95% CI 1.041-4.297; P = 0.038) were independent risk factors for RFS. CONCLUSION: This study found that PD-L1 was commonly expressed in the tumour stroma of CLOs and high PD-L1 expression was associated with poor prognosis.

Dual Plasmon Resonances and Tunable Electric Field in Structure-Adjustable Au Nanoflowers for Improved SERS and Photocatalysis.

Flower-like metallic nanocrystals have shown great potential in the fields of nanophononics and energy conversion owing to their unique optical properties and particular structures. Herein, colloid Au nanoflowers with different numbers of petals were prepared by a steerable template process. The structure-adjustable Au nanoflowers possessed double plasmon resonances, tunable electric fields, and greatly enhanced SERS and photocatalytic activity. In the extinction spectra, Au nanoflowers had a strong electric dipole resonance located around 530 to 550 nm. Meanwhile, a longitudinal plasmon resonance (730~760 nm) was obtained when the number of petals of Au nanoflowers increased to two or more. Numerical simulations verified that the strong electric fields of Au nanoflowers were located at the interface between the Au nanosphere and Au nanopetals, caused by the strong plasmon coupling. They could be further tuned by adding more Au nanopetals. Meanwhile, much stronger electric fields of Au nanoflowers with two or more petals were identified under longitudinal plasmon excitation. With these characteristics, Au nanoflowers showed excellent SERS and photocatalytic performances, which were highly dependent on the number of petals. Four-petal Au nanoflowers possessed the highest SERS activity on detecting Rhodamine B (excited both at 532 and 785 nm) and the strongest photocatalytic activity toward photodegrading methylene blue under visible light irradiation, caused by the strong multi-interfacial plasmon coupling and longitudinal plasmon resonance.

Combination of Multiple Hemodialysis Modes: Better Treatment Options for Patients Under Maintenance Hemodialysis.

PURPOSE: Chronic renal failure has become a major public health concern and treatment strategies are urgently needed. We aimed to investigate whether combination of hemodialysis modes was superior to regular hemodialysis for patients under maintenance hemodialysis. PATIENTS AND METHODS: A total of 144 patients with end-stage renal failure (ESRF) were enrolled in this single-center retrospective study. Patients received regular hemodialysis (HD) were included in HD group (n=52), patients received regular HD plus hemodiafiltration (HDF) in HD/HDF group (n=47), patients received the combination of regular HD, HDF and hemoperfusion (HP) in HD/HDF/HP group (n=45). After 1-month and 24-months treatment, therapeutic effects were assessed in terms of nutritional status, control of complications, dialysis adequacy, mean arterial pressure (MAP), infection rate and living quality. RESULTS: When patients received 1-month treatment, there were no statistically significant differences among three groups. After 24-months treatment, patients in HD/HDF and HD/HDF/HP group presented with better dialysis adequacy, lower MAP and infection rate, higher serum albumin, hemoglobin and calcium levels, lower serum phosphorus and intact parathyroid hormone levels, lower incidence of malnutrition and the Hamilton Depression Scale score, higher the Barthel Index score than HD group (P<0.05). The levels of calcium, phosphorus and intact parathyroid hormone in HD/HDF/HP group were lower than those in HD/HDF group (P<0.05). CONCLUSION: Our finding highly indicated that combination of hemodialysis modes was superior to regular HD for patients with ESRF in nutritional status, control of complications, dialysis adequacy, and living quality.

Properties of a Novel Animal Model of LPR.

BACKGROUND: Few satisfactory animal models of laryngopharyngeal reflux (LPR) is available. Interleukin-8 (IL-8) and vascular endothelial growth factor (VEGF) may be associated with the pathogenesis of LPR injuries and laryngeal carcinomas. OBJECTIVES: To establish an animal model of LPR and to explore the related pathological changes and cytokine expression in the vocal cord tissue. METHODS: Twenty rabbits were divided into experimental and control groups. Dilatation of the upper and lower esophageal sphincter were carried out in the experimental group. The pH of the pharynx, pathological, and ultrastructural changes of the laryngeal tissue, and expression of IL-8 and VEGF were compared between the experimental group and controls. RESULTS: pH monitoring results and the dilated intercellular space of the vocal cord mucosa showed that the experimental group developed laryngopharyngeal reflux. There were significant differences in the immunohistochemical staining scores of both IL-8 (P = 0.015) and VEGF (P = 0.007) between the experimental and control groups in the vocal cord tissue. CONCLUSIONS: We successfully established a model of LPR, showing histopathological and ultrastructural changes consistent with the disease. The expression of IL-8 and VEGF may increase during the pathogenesis of LPR.

The Relationship Between White Adipose Tissue Inflammation and Overweight/Obesity in Chinese Female Breast Cancer: A Retrospective Study.

INTRODUCTION: This study aims to investigate the relationship between breast white adipose tissue (WAT) inflammation and being overweight or obese, menopausal status, and metabolic syndrome-related indicators in breast cancer patients as well as the association between adipocyte size and the severity of WAT inflammation and body mass index (BMI). METHODS: The crown-like structures (CLS-B) formed by macrophages surrounding dying or dead adipocytes can be used to identify breast WAT inflammation. In this study, breast WAT and fasting blood from 136 Chinese women with breast cancer were collected for analysis. Cluster of differentiation 68 (CD68) immunohistochemical staining was performed to identify CLS-B, and the adipocyte size was measured by hematoxylin and eosin staining. RESULTS: The results showed that breast WAT inflammation usually occurs in overweight/obese breast cancer patients, and the severity of inflammation is positively correlated with adipocyte hypertrophy. We did not observe a direct association between WAT inflammation and menopausal status. In addition, the presence of WAT inflammation is associated with abnormalities in circulating factors associated with metabolic syndrome such as higher serum lipid, glucose, and C-reactive protein levels. CONCLUSION: Overweight/obese breast cancer patients may be more prone to breast WAT inflammation and may be associated with abnormalities in circulatory markers associated with metabolic syndrome.

Effect of Rhizobium Symbiosis on Low-Temperature Tolerance and Antioxidant Response in Alfalfa (Medicago sativa L.).

Low temperature-induced stress is a major environmental factor limiting the growth and development of plants. Alfalfa (Medicago sativa L.) is a legume well known for its tolerance of extreme environments. In this study, we sought to experimentally investigate the role of rhizobium symbiosis in alfalfa's performance under a low-temperature stress condition. To do this, alfalfa "Ladak+" plants carrying active nodules (AN), inactive nodules (IN), or no nodules (NN) were exposed to an imposed low temperature stress and their survivorship calculated. The antioxidant defense responses, the accumulation of osmotic regulation substances, the cell membrane damage, and the expression of low temperature stress-related genes were determined in both the roots and the shoots of alfalfa plants. We found that more plants with AN survived than those with IN or NN under the same low temperature-stress condition. Greater activity of oxidation protective enzymes was observed in the AN and IN groups, conferring higher tolerance to low temperature in these plants. In addition, rhizobia nodulation also enhanced alfalfa's ability to tolerate low temperature by altering the expression of regulatory and metabolism-associated genes, which resulted in the accumulation of soluble proteins and sugars in the nodulated plants. Taken together, the findings of this study indicate that rhizobium inoculation offers a practical way to promote the persistence and growth potential of alfalfa "Ladak+" in cold areas.

Tubular morphology preservation and doping engineering of Sn/P-codoped hematite for photoelectrochemical water oxidation.

Tubular hematite with high-concentration, uniform doping is regarded as a promising material for photoelectrochemical water oxidation. However, the high-temperature annealing commonly used for activating doped hematite inevitably causes deformation of the tubular structure and an increase in the trap states. In the present work, Sn-doped tubular hematite on fluorine-doped tin oxide (FTO) is successfully obtained at 750 °C from a Sn-coated FeOOH tube precursor. Sn/P codoping, which is rarely considered for hematite, is also achieved via a gas phase reaction in phosphide atmosphere. The tubular morphology allows the dopant to diffuse from both the inner and outer surfaces, thus decreasing the doping profile in the radial direction. The even distribution of Sn and P synergetically increases the carrier density of hematite by one order of magnitude, which shortens the width of the depletion layer to ca. 2.3 nm (compared with 19.3 nm for the pristine sample) and leads to prolonged carrier lifetime and efficient charge separation. In addition, this codoping protocol does not introduce additional surface trap states, as evidenced by the increased charge injection efficiency and surface kinetic analysis using intensity modulated photocurrent spectroscopy (IMPS). As a result, the morphology- and doping-engineered hematite exhibits photocurrents of 0.9 mA cm-2 at 1.23 V and 3.8 mA cm-2 at 2.0 V vs. RHE under AM 1.5 G illumination (100 mW cm-2) in 1.0 M NaOH, representing 4.5-fold and 4.8-fold enhancements, respectively, compared with the photocurrents of undoped hematite. The present method is shown to be effective for preparing multi-element-doped hematite nanotubes and may find broad application in the development of other nanotubular photoelectrodes with or without doping for efficient and robust water oxidation.

Cancer-Associated Fibroblasts Correlate with Tumor-Associated Macrophages Infiltration and Lymphatic Metastasis in Triple Negative Breast Cancer Patients.

Background: Cancer-associated fibroblasts (CAFs) have been shown to be among the most prominent cells in tumor microenvironment and play a significant role in accelerating tumor metastasis by interacting with other type of cells. Tumor-associated macrophages (TAMs), the predominant tumor-infiltrating immune cells, also play important roles in cancer progression. Here, we aimed to evaluate the effects of CAFs on infiltration of TAMs and lymphatic metastasis in triple-negative breast cancer (TNBC). Material and methods: The study included 278 patients with histologically confirmed TNBC. Immunohistochemical staining of α-smooth muscle actin and fibroblast activation protein were used to identify CAFs. Polarized functional status of infiltrated TAMs was detected by expression of CD163. The clinicopathological features were assessed from all the patients' medical records. Results: The CAFs-related markers were found to be expressed more frequently in TNBC patents with aggressive behaviors, including recurrence and poor histological differentiation. High activation of CAFs was positively correlated with elevated infiltration of polarized CD163-positive TAMs and lymph node metastasis in TNBC patients. Multivariate Cox analysis revealed that the activation of CAFs, TAMs infiltration, and lymph node metastasis were independent prognostic factors for disease-free survival in TNBC patients. Conclusion: Cancer-associated fibroblasts were associated with infiltration of CD163-positive macrophages and lymphatic metastasis, and may be potential prognostic predictors of TNBC.

Brand new 1D branched CuO nanowire arrays for efficient photoelectrochemical water reduction.

Developing high surface area nanostructured electrodes with fast charge separation is one of the main challenges for exploring cupric oxide (CuO)-based photocathodes in solar-driven hydrogen production applications. Herein, brand new 1D branched CuO nanowire arrays have been achieved on fluorine-doped tin oxide-coated glass (FTO) through a two-step wet chemical redox reaction. X-ray diffraction patterns, Raman spectra and X-ray photoelectron spectroscopy confirm the pure phase characteristic of the resulting branched CuO. In addition to the enlarged surface area of this advanced functional structure as compared with that of the 1D wire trunk, the charge injection and separation have been improved by rationally controlling the density of defects and size of branches. As a result, the optimized branched CuO exhibits photocurrent as high as 3.6 mA·cm-2 under AM 1.5G (100 mW·cm-2) illumination and 3.0 mA·cm-2 under visible light (λ > 420 nm) at 0.2 V vs. RHE in 0.5 M Na2SO4, which are 2.8- and 3.0-fold greater than those of 1D wire samples, respectively. In addition, the solution-processed approach established herein seems quite favourable for large-scale and low-cost manufacturing.

Organic-inorganic interactions of single crystalline organolead halide perovskites studied by Raman spectroscopy.

Organolead halide perovskites exhibit superior photoelectric properties, which have given rise to the perovskite-based solar cells whose power conversion efficiency has rapidly reached above 20% in the past few years. However, perovskite-based solar cells have also encountered problems such as current-voltage hysteresis and degradation under practical working conditions. Yet investigations into the intrinsic chemical nature of the perovskite material and its role on the performance of the solar cells are relatively rare. In this work, Raman spectroscopy is employed together with CASTEP calculations to investigate the organic-inorganic interactions in CH3NH3PbI3 and CH3NH3PbBr3-xClx perovskite single crystals with comparison to those having ammonic acid as the cations. For Raman measurements of CH3NH3PbI3, a low energy line of 1030 nm is used to avoid excitation of strong photoluminescence of CH3NH3PbI3. Raman spectra covering a wide range of wavenumbers are obtained, and the restricted rotation modes of CH3-NH3(+) embedded in CH3NH3PbBr3 (325 cm(-1)) are overwhelmingly stronger over the other vibrational bands of the cations. However, the band intensity diminishes dramatically in CH3NH3PbBr3-xClx and most of the bands shift towards high frequency, indicating the interaction with the halides. The details of such an interaction are further revealed by inspecting the band shift of the restricted rotation mode as well as the C-N, NH3(+) and CH3 stretching of the CH3NH3(+) as a function of Cl composition and length of the cationic ammonic acids. The results show that the CH3NH3(+) interacts with the PbX3(-) octahedral framework via the NH3(+) end through N(+)-HX hydrogen bonding whose strength can be tuned by the composition of halides but is insensitive to the size of the organic cations. Moreover, an increase of the Cl content strengthens the hydrogen bonding and thus blueshifts the C-N stretching bands. This is due to the fact that Cl is more electronegative than Br and an increase of the Cl content decreases the lattice constant of the perovskite. The findings of the present work are valuable in understanding the role of cations and halides in the performance of MAPbX3-based perovskite solar cells.

[Effects of elevated O3 concentration and UV-B radiation on the chlorophyll content and active oxygen metabolism of soybean leaves].

Taking the soybean (Glycine max) cultivar Tiefeng 29 as test material, and by using open-top chamber, this paper studied the effects of elevated O3 concentration and UV-B radiation on the leaf chlorophyll content, lipid peroxidation, reactive oxygen species (ROS) production rate, anti-oxidation enzymes activities, and the grain yield. During the growth period of soybean, as compared with the control, the leaf Chl a, Chl b and Chl (a+b) contents under the stresses of O3 and UV-B had a decreasing trend, the relative electrical conductivity, malondialdehyde content, superoxide anion (O2) production rate, and hydrogen peroxide (H2O2) content increased, and the activities of superoxide dismutase, peroxidase and catalase as well as the grain yield decreased. O3+ UV stress aggravated the leaf membrane lipid peroxidation, promoted the ROS production, and decreased the plant antioxidant capacity and leaf chlorophyll content. The negative effects of O3 stress on soybean leaves were more close to the impacts of O3+UV stress, suggesting that O3 might play an important role in the combined stress.

Relativistic DFT study on the reaction mechanism of second-row transition metal Ru with CO2.

To estimate the importance of relativistic effects on the reaction mechanisms between Ru and CO2, the potential energy surfaces have been performed in the triplet and quintet electronic states using quasi-relativistic (Pauli), zero-order regularly approximated (ZORA), and nonrelativistic (NR) density functional theory (DFT) at the PW91/TZP level. The results demonstrate that there are two rival reaction mechanisms: one is an addition mechanism and the other is an insertion mechanism in the triplet state. The only mechanism in the quintet state is the insertion mechanism. The most favored reaction mechanism in Ru + CO2 is that the Ru atom in its ground state first attacks the CO bond of CO2, forming q-Ru(CO)O (5A'') with the insertion mechanism, and then undergoes an intersystem crossing to t-Ru(CO)O (3A''). Then it crosses t-TS3 to produce t-ORuCO molecule. The relativistic effects are important for reactivity of the second-row transition metal to CO2. In the key step of t-Ru(CO)O via t-TS3 to t-ORuCO, relativistic effects reduce the barrier energy by 10.3 kcal/mol, which is nearly half the nonrelativistic barrier energy.