Na Substitution Steering RuO6 Unit in Ruthenium Pyrochlores for Enhanced Oxygen Evolution in Acid.

Although Ruthenium-based pyrochlore oxides can function as promising catalysts for acidic water oxidation, their limitations in terms of stability and activity still need to be addressed for further application in practical conditions. In this work, the possibility to enhance both oxygen evolution reaction activity and durability of Gd2Ru2O7- δ through partial replacement with Na+ in Gd3+ sites is first offered, leading to the electronic and geometric regulation of active center RuO6. Na+ triggers the emergence of Ru<4+ and the electron rearrangement of active-centered RuO6. Specifically, Ru ions with a negative d-band center after Na+ doping exhibit weaker adsorption energies of *O and result in the conversion of the rate-limiting step from *O/*OOH to *OH/O*, reducing energy barriers for boosting activities. Therefore, the NaxGd2- xRu2O7- δ requires a low overpotential of 260 mV at 10 mA cm-2 in 0.1 m HClO4 electrolyte. Moreover, the higher formation energy of Ru vacancy and less distorted RuO6 enable the as-prepared NaxGd2- xRu2O7- δ to operate steadily at 10 mA cm-2 for 300 h and multi-current chronopotentiometry with current densities from 20 to 100 mA cm-2 for 60 h in acidic proton exchange membrane electrolyzer, respectively.

Open-cage metallo-azafullerenes as efficient single-atom catalysts toward oxygen reduction reaction.

Very recently, open-cage metallo-azafullerenes PbC100N4H4 and Pb2C100N4H4 containing one Pb-N4-C moiety have been synthesized via the electron beam. Herein, we utilized density functional theory calculations in combination with ab initio molecular dynamics (AIMD) simulations to study the geometric and electronic structures, bonding properties, thermodynamic stability, and catalytic performance of MC100N4H4 and M2C100N4H4 (M = Ge, Sn, Pb). Metal-nitrogen distances and metal-metal distances increase along with the metal radius while the metal atom is positively charged. Energy decomposition analysis revealed that the bonding interactions between M and the C100N4H4 fragment could be described as the donor-acceptor interaction between M(ns0(n-1)d10np4) and C100N4H4 fragment, in which the orbital interactions terms contribute more than the electrostatic interactions. AIMD simulations demonstrate that those metallo-azafullerenes exhibit thermodynamic stability at room temperature. These metallo-azafullerenes, which could serve as typical carbon-supported single-atom catalysts, possess enhanced catalytic performance toward the oxygen reduction reaction (ORR) compared to the planar catalysts, which is attributed to the curvature of metallo-azafullerenes. GeC100N4H4 and SnC100N4H4 exhibit high catalytic performance in the 4e-ORR pathway to H2O, whereas only PbC100N4H4 is suitable for the 2e-ORR reaction pathway because of the difficulty in obtaining electrons. All M2C100N4H4 favors the 4e-reaction pathway due to the presence of the axial metal atom. Our finding of open-cage metallo-azafullerenes as efficient single-atom catalysts holds profound implications for both fundamental research in catalysis and practical applications in fuel cells and other electrochemical devices.

Risk assessment and source identification of soil heavy metals: a case study of farmland soil along a river in the southeast of a mining area in Southwest China.

To investigate the heavy metals (HMs) contamination of surface farmland soil along the river in the southeast of a mining area in southwest China and identify the contamination sources, 54 topsoil samples were collected and the concentrations of seven elements (Zn, Ni, Pb, Cu, Hg, Cr, and Co) were determined by inductively coupled plasma optical emission spectrometry (ICP-OES) and atomic fluorescence spectrometry (AFS). The geo-accumulation index ([Formula: see text]) and comprehensive potential ecological risk index ([Formula: see text]) were used for analysis to determine the pollution degree of HMs and the risk level of the study area. Meanwhile, the Positive Matrix Factorization (PMF) model was combined with a variety of statistical methods to determine the sources of HMs. To explore the influence of the river flowing through the mining area on the concentrations of HMs in the farmland soil, 15 water samples were collected and the concentrations of the above seven elements were determined. The results showed that the concentrations of Pb, Cu, and Zn in soil all exceeded the risk screening value, and Pb in soil of some sampling sites exceeded control value of "Agricultural Land Soil Pollution Risk Control Standard".[Formula: see text] showed that Pb was heavily contaminated, while Cu and Zn were moderately contaminated. RI showed that the study area was at moderate risk. PMF and various statistical methods showed that the main source of HMs was the industrial source. In the short term, the river flowing through the mine has no significant influence on the concentration of HMs in the soil. The results provide a reference for the local government to control contamination and identify the sources of HMs.

Synthesis of Multifunctional Organic Molecules via Michael Addition Reaction to Manage Perovskite Crystallization and Defect.

Additive engineering plays a pivotal role in achieving high-quality light-absorbing layers for high-performance and stable perovskite solar cells (PSCs). Various functional groups within the additives exert distinct regulatory effects on the perovskite layer. However, few additive molecules can synergistically fulfill the dual functions of regulating crystallization and passivating defects. Here, we custom-synthesized 2-ureido-4-pyrimidone (UPy) organic small molecules with diverse functional groups as additives to modulate crystallization and defects in perovskite films via the Michael addition reaction. Theoretical and experimental investigations demonstrate that the -OH groups in UPy exhibit significant effects in fixing uncoordinated Pb2+ ions, passivation of lead-iodide antisite defects, alleviating hysteresis, and reducing non-radiative recombination. Furthermore, the enhanced C=O and -NH2 motifs interact with the A-site cation via hydrogen bonding, which relieves residual strain and adjusts crystal orientation. This strategy effectively controls perovskite crystallization and passivates defects, ultimately enhancing the quality of perovskite films. Consequently, the open-circuit voltage of the UPy-based p-i-n PSCs reaches 1.20 V, and the fill factor surpasses 84 %. The champion device delivers a power conversion efficiency of 25.75 %. Remarkably, the unencapsulated device maintained 96.9 % and 94.5 % of its initial efficiency following 3,360 hours of dark storage and 1,866 hours of 1-sun illumination, respectively.

DFT-based Machine Learning for Ensemble Effect of Pd@Au Electrocatalysts on CO2 Reduction Reaction.

The ensemble effect due to variation of Pd content in Pd-Au alloys have been widely investigated for several important reactions, including CO2 reduction reaction (CO2 RR), however, identifying the stable Pd arrangements on the alloyed surface and picking out the active sites are still challenging. Here we use a density functional theory (DFT) based machine-learning (ML) approach to efficiently find the low-energy configurations of Pd-Au(111) surface alloys and the potentially active sites for CO2 RR, fully covering the Pd content from 0 to 100 %. The ML model is actively learning process to improve the predicting accuracy for the configuration formation energy and to find the stable Pd-Au(111) alloyed surfaces, respectively. The local surface properties of adsorption sites are classified into two classes by the K-means clustering approach, which are closely related to the Pd content on Au surface. The classification is reflected in the variation of adsorption energy of CO and H: In the low Pd content range (0-60 %) the adsorption energies over the surface alloys can be tuned significantly, and in the medium Pd content (37-68 %), the catalytic activity of surface alloys for CO2 RR can be increased by increase the Pd content and attributed to the meta-stable active site over the surface. Thus, the active site-dependent reaction mechanism is elucidated based on the ensemble effect, which provides new physical insights to understand the surface-related properties of catalysts.

Laying down of gold nanorods monolayers on solid surfaces for surface enhanced Raman spectroscopy applications.

Laying-down gold nanorods (GNRs) of a monolayer immobilized on a solid substrate was realized with a hybrid method, a combination of three elemental technologies: surface modification, electrophoresis, and solvent evaporation. The self-assembly of CTAB-protected GNRs in the solution was induced by 0.05 mM of EDTA. The assembled GNRs were deposited in a laying-down form on the solid surface during the hybrid method. The final coverage was over 71% on the substrate with an area larger than 0.6 cm2. The spacing between the sides of the GNRs was fixed to be 4.6 ± 0.9 nm by the thermal annealing-promoted crystalline packing of the bilayer of CTAB salt-bridged with EDTA. The obtained laying-down GNRs of a monolayer on the gold substrate show a small shift of the transverse LSPR around 550-570 nm (with a width of around 100 nm) and a large red shift of the longitudinal LSPR to be 900-1050 nm (with a width of 500 nm), because of the strong electromagnetic coupling between the GNRs and gold substrate. Therefore it can be used in a wide range of wavelengths for surface enhanced Raman spectroscopy (SERS) applications. The film has a high enhancement factor with 105 for R6G.

The ENUF method-Ewald summation based on nonuniform fast Fourier transform: Implementation, parallelization, and application.

Computer simulations of model systems are widely used to explore striking phenomena in promising applications spanning from physics, chemistry, biology, to materials science and engineering. The long range electrostatic interactions between charged particles constitute a prominent factor in determining structures and states of model systems. How to efficiently calculate electrostatic interactions in simulation systems subjected to partial or full periodic boundary conditions has been a grand challenging task. In the past decades, a large variety of computational schemes has been proposed, among which the Ewald summation method is the most reliable route to accurately deal with electrostatic interactions between charged particles in simulation systems. In addition, extensive efforts have been done to improve computational efficiencies of the Ewald summation based methods. Representative examples are approaches based on cutoffs, reaction fields, multi-poles, multi-grids, and particle-mesh schemes. We sketched an ENUF method, an abbreviation for the Ewald summation method based on the nonuniform fast Fourier transform technique, and have implemented this method in particle-based simulation packages to calculate electrostatic energies and forces at micro- and mesoscopic levels. Extensive computational studies of conformational properties of polyelectrolytes, dendrimer-membrane complexes, and ionic fluids demonstrated that the ENUF method and its derivatives conserve both energy and momentum to floating point accuracy, and exhibit a computational complexity of O N log N with optimal physical parameters. These ENUF based methods are attractive alternatives in molecular simulations where high accuracy and efficiency of simulation methods are needed to accelerate calculations of electrostatic interactions at extended spatiotemporal scales.

Phosphorus and Yttrium Codoped Co(OH)F Nanoarray as Highly Efficient and Bifunctional Electrocatalysts for Overall Water Splitting.

Rational design and synthesis of bifunctional electrocatalysts with high efficiency and low-cost for overall water splitting is still a challenge. A simple approach is reported to prepare a phosphorus and yttrium codoped cobalt hydroxyfluoride (YP-Co(OH)F) nanoarray on nickel foam, which displays high-performance for both hydrogen evolution reaction (HER) and oxygen evolution reaction in alkaline solution. The codoping of yttrium and phosphorus into Co(OH)F leads to a tuned electronic environment and favorable electron transfer, thus resulting in superior water splitting activity. The YP-Co(OH)F electrode only requires an overpotential of 238 mV to reach a current density of 10 mA cm-2 (η10 ), much smaller than RuO2 (302 mV). Moreover, it displays an overpotential of 55 mV at η10 for HER, similar to that of Pt/C. When YP-Co(OH)F is used as both anode and cathode in a two-electrode configuration, it only demands a cell potential of 1.54 V at η10 , lower than the IrO2 ||Pt/C couple (1.6 V) as well as other recently reported electrocatalysts. It even maintains stable water splitting for 300 h. Such a two-electrode device can be easily driven by a 1.5 V silicon solar cell in sunlight, proving the potential of the promising catalyst for large-scale electrolytic water splitting.

Modification of Carbon Nanotubes via Birch Reaction for Enhanced HER Catalyst by Constructing Pearl Necklace-Like NiCo2 P2 -CNT Composite.

Combining transition metal phosphides (TMPs) with carbon nanotubes (CNTs) is a promising and proven approach to enhance their performance in the electrochemical hydrogen evolution reaction (HER), due to the excellent conductivity and stability of CNTs. Generally, the deep oxidation of CNTs to form oxygen-containing groups on their surface is indispensable before combining them with TMPs. However, such approaches inevitably introduce a large number of defects to CNTs and apparently decrease their stability and electrical conductivity. Hence, fabricating TMP-CNT composites which does not come at the expense of CNTs' high electrical conductivity is quite desirable. In this work, alkylated CNTs (named as ACNT) functionalized via the Birch reaction are used to prepare the pearl necklace-like NiCo2 P2 -ACNT composites for electrocatalysts toward HER in acidic and alkaline conditions, respectively. The X-ray photoelectron spectroscopy, transmission electron microscope, and Fourier transform infrared spectroscopy characterizations indicate that the ACNTs are well modified with functional groups and keep their structural integrity, thereby maximizing their excellent conductivity. Compared to bare NiCo2 P2 and the NiCo2 P2 -CNT composites prepared with mildly oxidized CNTs and deeply oxidized CNTs, the NiCo2 P2 -ACNTs show far better HER performance and much faster kinetics.

Accelerating electrostatic interaction calculations with graphical processing units based on new developments of Ewald method using non-uniform fast Fourier transform.

We present new algorithms to improve the performance of ENUF method (F. Hedman, A. Laaksonen, Chem. Phys. Lett. 425, 2006, 142) which is essentially Ewald summation using Non-Uniform FFT (NFFT) technique. A NearDistance algorithm is developed to extensively reduce the neighbor list size in real-space computation. In reciprocal-space computation, a new algorithm is developed for NFFT for the evaluations of electrostatic interaction energies and forces. Both real-space and reciprocal-space computations are further accelerated by using graphical processing units (GPU) with CUDA technology. Especially, the use of CUNFFT (NFFT based on CUDA) very much reduces the reciprocal-space computation. In order to reach the best performance of this method, we propose a procedure for the selection of optimal parameters with controlled accuracies. With the choice of suitable parameters, we show that our method is a good alternative to the standard Ewald method with the same computational precision but a dramatically higher computational efficiency.

Tuning Surface Properties of Low Dimensional Materials via Strain Engineering.

The promising and versatile applications of low dimensional materials are largely due to their surface properties, which along with their underlying electronic structures have been well studied. However, these materials may not be directly useful for applications requiring properties other than their natal ones. In recent years, strain has been shown to be an additionally useful handle to tune the physical and chemical properties of materials by changing their geometric and electronic structures. The strategies for producing strain are summarized. Then, the electronic structure of quasi-two dimensional layered non-metallic materials (e.g., graphene, MX2, BP, Ge nanosheets) under strain are discussed. Later, the strain effects on catalytic properties of metal-catalyst loaded with strain are focused on. Both experimental and computational perspectives for dealing with strained systems are covered. Finally, an outlook on engineering surface properties utilizing strain is provided.

Early- and Middle-Term Surgical Outcomes in Patients with Heterotaxy Syndrome.

OBJECTIVES: Heterotaxy syndrome is a recognized risk factor for surgical cardiac interventions. We evaluated the early- and middle-term results of a surgical intervention for patients with heterotaxy syndrome. METHODS: A total of 42 patients with heterotaxy syndrome were enrolled (September 2008 to March 2015). Left and right atrial isomerism were identified in 26% (11 out of 42) and 74% of patients (31 out of 42), respectively. The median age of the patients at the time of surgery was 6.8 months (range: 5 days to 22.3 years). Biventricular repair was completed in 3 patients with left atrial isomerism. Seventeen out of 39 patients who were scheduled for single ventricular repair completed a modified Fontan procedure. RESULTS: The hospital mortality rate was 4.7% (2 out of 42). Another 5 deaths occurred in the remaining survivors following hospital discharge with a follow-up duration of 45.8 ± 23.6 months (range: 13-111 months). The 1-year and 5-year survival rates were 88.1% (37/42) and 83.3% (35/42), respectively. Univariate analysis and multivariate analysis identified pulmonary venous obstruction and atrioventricular valve replacement as additional risk factors for mortality. CONCLUSIONS: Right ventricular bypass surgery remains the preferred palliative procedure for patients with heterotaxy syndrome. Based on the current results, the early- and middle-term outcomes are satisfactory.

[Surgical treatment of total anomalous pulmonary venous connection under 6 months of age].

OBJECTIVE: To discuss the experience of surgical treatment of total anomalous pulmonary venous connection (TAPVC) in infants. METHODS: The clinic data of 84 cases with TAPVC under 6 months of age underwent surgical treatment at Department of Cardiac Surgery, Guangzhou Women and Children's Medical Center from January 2012 to October 2015 were analyzed retrospectively. There were 58 male and 26 female patients. The patients were aged 1 days to 6 months with a mean of (2.4±2.2) months at surgery, including 22 newborns. Body weight was 1.8 to 6.8 kg with a mean of (4.3±1.2) kg. There were 24 cases of intracardiac type, 46 cases of supracardiac type, 10 cases of infracardiac type and 4 cases of mixed type. There were 26 cases received emergent operation. There were 14 cases used Sutureless technique in operations and 46 cases used conventional methods in the no-intracardiac type cases, and 2 cases enlarged the anastomsis with autologous pericardium. According to the condition, corrective surgeries of other anomalies were performed in the meantime, including 3 Warden operations (right side), 3 bilateral bidirectional Gleen operation, 2 correction of unroofed coronary sinus syndrome, 1 coarctation of aorta correction with deep hypothermic circulation arrest, and 1 repair of ventricular septal defect. RESULTS: The ratio of newborn was higher in Sutureless technique group than in conventional methods group (7/14 vs. 32.6%, χ(2)=4.927, P=0.043), and mean age was less ((1.8±0.4) months vs. (2.4±2.2) months, F=4.257, P=0.042), but there were no difference in body weight, cardiopulmonary bypass time and aorta clamped time between the two groups. Followed up for 1 to 46 months, 10 cases (11.9%) died overall and the mortality of intracardiac (3/10) and mixed (2/4) type were much higher than in intracardiac (4.2%) and supracardiac (13.0%) type. The mortality were no difference between newborn and infants, or whether emergent operation, or Sutureless technique and conventional methods. The maximal pulmonary venous flow velocity was abnormal speed-up >1.8 m/s at 1 week and 1 to 3 months post-operation mostly. CONCLUSIONS: The mortality of TAPVC was differed by different types. Intrinsic pulmonary vein stenosis maybe the main cause of mortality. The high quality of anastomsis could reduce the operative mortality.

Molten salt medium synthesis of wormlike platinum silver nanotubes without any organic surfactant or solvent for methanol and formic acid oxidation.

In the current research, the PtxAgy (x/y = 86/14, 79/21, 52/48, 21/79, 11/89) nanoparticles (NPs) are synthesized in the KNO3-LiNO3 molten salts without using any organic surfactant or solvent. The SEM results suggest that when the content of Ag is higher than 48%, the wormlike PtxAgy nanotubes (NTs) can be synthesized. The diameter of the PtxAgyNTs shows a slow decrease with the increase of Ag content. The TEM and HRTEM results indicate that the growth of hollow PtxAgy NTs undergoes an oriented attachment process and a Kirkendall effect approach. The results of cyclic voltammetry (CV) measurement indicate that the Pt52Ag48 catalyst presents a remarkable enhancement for methanol electrooxidation, while the Pt86Ag14 catalyst prefers electrochemically oxidizing formic acid compared with that of the commercially available Pt black.

Early and mid-term results of the arterial switch operation in patients with intramural coronary artery.

Intramural coronary artery is known to be a risk factor for early death after an arterial switch operation (ASO). We evaluated the early and mid-term results of ASO for patients with intramural coronary artery. From September 2008 to March 2012, seven patients with an intramural coronary artery underwent ASO at our hospital. The mean age at operation was 2.4 months (2 days-1 year), and the mean body weight was 4.3 ± 2.2 kg. The mean follow-up was 35.3 ± 16.5 months (22-63 months). The individual coronary button technique was used in seven patients. The intramural segment was unroofed in one patient; in one patient with myocardial ischemia, the intramural segment was unroofed and enlarged using a patch of autologous pericardium. There was one operative death because of low cardiac output syndrome (14.2% mortality). In the same time period at our hospital, three deaths were reported in 68 ASO patients (4.4% mortality) without an intramural coronary artery. There was no statistical difference between the two groups (P > 0.05). There were no late deaths, and no patients required a coronary intervention. Intramural coronary artery is a well-known risk factor for early death after ASO. To optimize results, the coronary transfer technique should be tailored to each patient's particular anatomy. Intraoperative or postoperative myocardial ischemia should be addressed aggressively by immediately reimplanting the coronary artery. Unroofing the intramural segment, even the distal portion, should restore normal coronary blood flow.

Synthesis of colloidal metal and metal alloy nanoparticles for electrochemical energy applications.

This Review is focused on the recent progresses in the synthetic approaches to the precise control of structure, size, shape, composition and multi-functionality of metal and metal alloy nanoparticles. Many of these strategies have been developed based on colloidal methods, and to limited extent, the galvanic and other methods. The shape, size and composition often govern the chemical and catalytic properties that are important for electrochemical energy applications. The structure-property relationship and the design in controllable structures and morphologies for specific reactions such as oxygen reduction reaction (ORR) are emphasized.

[Surgical treatment of congenital vascular ring].

OBJECTIVE: To discuss the diagnosis and surgical treatment of congenital vascular ring and prognostic factors. METHODS: The clinic data of 42 cases of congenital vascular from January 2010 to December 2013 was analyzed retrospectively (accounting for 1.04% congenital heart operations over the same period ). There were 26 male and 16 female patients, aged at surgery 24 days to 6 years (average 10.7 months). The diagnosis including pulmonary artery sling in 26 cases, double aortic arch in 10 cases, right aortic arch with aberrant left subclavian artery in 3 cases, pulmonary artery sling and right aortic arch with vagus left subclavian artery in 2 cases, pulmonary artery sling and left aortic arch with vagus right subclavian artery in 1 case. In addition to 4 cases the remaining 38 patients were still combined with other cardiovascular malformations. Thirty-six cases of children underwent spiral CT airway remodeling, 23 children underwent fiber- bronchoscopy. In addition to 2 cases of airway abnormalities not seen, the rest of the children were present in varying degrees in different parts of tracheal stenosis or tracheomalacia. All patients underwent surgical correction of congenital vascular ring, concomitant heart deformity correction surgery according to the situation (7 cases of atrial septal defect repair, 3 of ventricular septal defect repair, 1 of mitral valvuloplasty, 1 of bi-Glenn, 1 of coarctation of the aorta correction with ventricular septal defect repair, 1 of trilogy of Fallot correction). One case suffered resection of tracheal stenosis and Slide tracheoplasty simultaneously, another case was implanted tracheal stenting postoperatively after pulmonary artery sling correction. RESULTS: Three patients died in hospital (7.1%), the cause of death were recurrent granuloma formation postoperatively. Remaining 39 patients were successfully discharged. The median time of overall survival of children with mechanical ventilation was 14 h (22 h) (M (Q(R))), median ICU residence time was 5 d (8 d), and the median in-hospital time was 19 d (9 d). Tracheal intubation time and postoperative ICU duration time in children with pulmonary artery sling children were much more than in children with double aortic arch (23 h (123 h) vs. 9 h(9 h), 7 d (13 d) vs. 4 d (2 d)), but the difference were not statistically significant. There was significant difference in the duration of hospitalization between the patient with the pulmonary artery sling and double aortic arch (23 d (9 d) vs. 16 d(6 d)) (χ(2) = 10.157, P = 0.006). CONCLUSIONS: The recent results of surgical treatment of congenital vascular ring is safe and effective. The extent and scope of tracheal stenosis and tracheomalacia is a critical influence prognosis.

A novel deep eutectic solvent modified magnetic covalent organic framework for the selective separation and determination of trace copper ion in medicinal plants and environmental samples.

BACKGROUND: Pretreatment techniques should be introduced before metal ion determination because there is very low content of heavy metals in Chinese medicinal plants and environmental samples. Magnetic dispersive micro solid phase extraction (MDMSPE) has been widely used for the separation and adsorption of heavy metal pollutants in medicinal plants and environmental samples. However, the majority of MDMSPE adsorbents have certain drawbacks, including low selectivity, poor anti-interference ability, and small adsorption capacity. Therefore, modifying currently available adsorption materials has gained attention in research. RESULTS: In this study, a novel adsorbent MCOF-DES based on a magnetic covalent organic framework (MCOF) modified by a new deep eutectic solvent (DES) was synthesized for the first time and used as an adsorbent of MDMSPE. The MDMSPE was combined with inductively coupled plasma optical emission spectrometry (ICP-OES) for selective separation, enrichment, and accurate determination of trace copper ion (Cu2+) in medicinal plants and environmental samples. Various characterization results show the successful preparation of new MCOF-DES. Under the optimal conditions, the enrichment factor (EF) of Cu2+ was 30, the limit of detection (LOD) was 0.16 µg L-1, and the limit of quantitation (LOQ) was 0.54 µg L-1. The results for the determination of Cu2+ were highly consistent with those of inductively coupled plasma mass spectrometry (ICP-MS), which verified the accuracy and reliability of the method. SIGNIFICANCE: The established method based on a new adsorption material MCOF-DES has achieved the selective separation and determination of trace Cu2+ in medicinal and edible homologous medicinal materials (Phyllanthus emblica Linn.) and environmental samples (soil and water), which provides a promising, selective, and sensitive approach for the determination of trace Cu2+ in other real samples.

Investigation of natural deep eutectic solvent for the extraction of crude polysaccharide from Polygonatum kingianum and influence of metal elements on its immunomodulatory effects.

In this study, natural deep eutectic solvent (NADES) was used to extract Polygonatum kingianum crude polysaccharide (PKCP) and response surface methodology (RSM) was designed to optimize the extraction procedure. The immunomodulatory effect of PKCP and the influence of metal elements on its immunomodulatory effect were further discussed. The optimum conditions for PKCP extraction were obtained by RSM optimization: NADES were synthesized with a 1:2 choline chloride-glycerol molar ratio, then extracted at a liquid-solid ratio of 16.6 mL g-1 and water content of 31.2 % for 60 min at 60 °C. This method was used for the extraction of PKCP, and the extraction efficiency was 29.69 %, which was 2.5 times greater than the conventional method of water extraction. In the concentration range of 200-800 µg mL-1, PKCP could activate macrophages, promoting NO secretion and mRNA expression of interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS) in a dose-dependent way. NO secretion and cytokine expression were not affected when the metal elements were spiked to the equivalent of the metal elements contained in Polygonatum kingianum. When the content of metal elements was higher, the secretion of NO and the gene expression of iNOS were both decreased, which may affect the immunomodulatory effect of Polygonatum kingianum.

Transparent Recombination Layers Design and Rational Characterizations for Efficient Two-Terminal Perovskite-Based Tandem Solar Cells.

Two-terminal (2T) perovskite-based tandem solar cells (TSCs) arouse burgeoning interest in breaking the Shockley-Queisser (S-Q) limit of single-junction solar cells by combining two subcells with different bandgaps. However, the highest certified efficiency of 2T perovskite-based TSCs (33.9%) lags behind the theoretical limit (42-43%). A vital challenge limiting the development of 2T perovskite-based TSCs is the transparent recombination layers/interconnecting layers (RLs) design between two subcells. To improve the performance of 2T perovskite-based TSCs, RLs simultaneously fulfill the optical loss, contact resistance, carrier mobility, stress management, and conformal coverage requirements. In this review, the definition, functions, and requirements of RLs in 2T perovskite-based TSCs are presented. The insightful characterization methods applicable to RLs, which are inspiring for further research on the RLs both in 2T perovskite-based two-junction and multi-junction TSCs, are also highlighted. Finally, the key factors that currently limit the performance enhancement of RLs and the future directions that should be continuously focused on are summarized.