Unveil the origin of voltage oscillation for sodium-ion batteries operating at -40 °C

Voltage oscillation at subzero in sodium-ion batteries (SIBs) has been a common but overlooked scenario, almost yet to be understood. For example, the phenomenon seriously deteriorates the performance of Na3V2(PO4)3 (NVP) cathode in PC (propylene carbonate)/EC (ethylene carbonate)-based electrolyte at -20 °C. Here, the correlation between voltage oscillation, structural evolution, and electrolytes has been revealed based on theoretical calculations, in-/ex-situ techniques, and cross-experiments. It is found that the local phase transition of the Na3V2(PO4)3 (NVP) cathode in PC/EC-based electrolyte at -20 °C should be responsible for the oscillatory phenomenon. Furthermore, the low exchange current density originating from the high desolvation energy barrier in NVP-PC/EC system also aggravates the local phase transformation, resulting in severe voltage oscillation. By introducing the diglyme solvent with lower Na-solvent binding energy, the voltage oscillation of the NVP can be eliminated effectively at subzero. As a result, the high capacity retentions of 98.3% at -20 °C and 75.3% at -40 °C are achieved. The finding provides insight into the abnormal SIBs degradation and brings the voltage oscillation behavior of rechargeable batteries into the limelight.

Small-Molecule Copper Chloride Modulating the Buried Interfaces of Perovskite Solar Cells

In perovskite solar cells (PSCs), tin dioxide (SnO2) is a highly effective electron transport material. On the other hand, the low intrinsic conductivity of SnO2, the high trap-state density on the surface and bulk of SnO2, and inadequate interface contacts between SnO2 and perovskite significantly impact device performance. Herein, small-molecule copper(II) chloride (CuCl2) is introduced into the SnO2 dispersion, which inhibits the agglomeration of SnO2 colloids and improves the quality of the electron transport layer. Furthermore, the introduction of CuCl2 optimizes the energy-level array between the ETL and perovskite layer (PVK) and passivates the anion/cation defects in SnO2, perovskite, and their interface, realizing the systematic modulation of the photoelectronic properties of the ETLs and PVKs as well as the PVK/ETL. As a result, the CuCl2-opmized PSC exhibits an impressive power conversion efficiency of 23.71%, along with improved stability.

Poly(3-hexylthiophene)/perovskite Heterointerface by Spinodal Decomposition Enabling Efficient and Stable Perovskite Solar Cells

The best research-cell efficiency of perovskite solar cells (PSCs) is comparable with that of mature silicon solar cells (SSCs); However, the industrial development of PSCs lags far behind SSCs. PSC is a multiphase and multicomponent system, whose consequent interfacial energy loss and carrier loss seriously affect the performance and stability of devices. Here, by using spinodal decomposition, a spontaneous solid phase segregation process, in situ introduces a poly(3-hexylthiophene)/perovskite (P3HT/PVK) heterointerface with interpenetrating structure in PSCs. The P3HT/PVK heterointerface tunes the energy alignment, thereby reducing the energy loss at the interface; The P3HT/PVK interpenetrating structure bridges a transport channel, thus decreasing the carrier loss at the interface. The simultaneous mitigation of energy and carrier losses by P3HT/PVK heterointerface enables n-i-p geometry device a power conversion efficiency of 24.53% (certified 23.94%) and excellent stability. These findings demonstrate an ingenious strategy to optimize the performance of PSCs by heterointerface via Spinodal decomposition.

Maimendong decoction regulates M2 macrophage polarization to suppress pulmonary fibrosis via PI3K/Akt/FOXO3a signalling pathway-mediated fibroblast activation

ETHNOPHARMACOLOGICAL RELEVANCE

Mai Men Dong decoction (MMDD), a traditional Chinese medicine formula, is relevant to ethnopharmacology due to its constituents and therapeutic properties. The formula contains herbs like Ophiopogon japonicus (Thunb.) Ker Gawl., Pinellia ternata (Thunb.) Makino, Panax ginseng C.A.Mey, Glycyrrhiza uralensis Fisch, and Ziziphus jujuba Mill, Oryza sativa L., which have been used for centuries in Chinese medicine. These herbs provide a comprehensive approach to treating respiratory conditions by addressing dryness, cough, and phlegm. Ethnopharmacological studies have explored the scientific basis of these herbs and identified active compounds that contribute to their medicinal effects. The traditional usage of MMDD by different ethnic groups reflects their knowledge and experiences. Examining this formula contributes to the understanding and development of ethnopharmacology.

AIM OF THE STUDY

In the case of pulmonary fibrosis (PF), treating it can be challenging due to the limited treatment options available. This study aimed to assess the potential of MMDD as a treatment for PF by targeting macrophages and the PI3K/Akt/FOXO3a signaling pathway.

MATERIALS AND METHODS

In a mouse model of PF, we investigated the effects of MMDD on inflammation, fibrosis, and M2 macrophage infiltration in lung tissue. Additionally, we examined the modulation of pro-fibrotic factors and key proteins in the PI3K/Akt/FOXO3a pathway. In vitro experiments involved inducing M2-type macrophages and assessing the impact of MMDD on fibroblast activation and the PI3K/Akt/FOXO3a pathway.

RESULTS

Results demonstrated that MMDD improved weight, reduced inflammation, and inhibited M2 macrophage infiltration in mouse lung tissue. It downregulated pro-fibrotic factors, such as TGF-β1 and PDGF-RB, as well as markers of fibroblast activation. MMDD also exhibited regulatory effects on key proteins in the PI3K/Akt/FOXO3a signaling pathway.

CONCLUSIONS

MMDD inhibited M2 macrophage polarization and released profibrotic factors that inhibited pulmonary fibrosis. As a result, the PI3K/Akt/FOXO3a signaling pathway is suppressed. MMDD is proving to be a successful treatment for PF. However, further research is needed to validate its effectiveness in clinical practice.

COVID-19 Omicron variant infection has minimal impact on maternal and neonatal outcomes: A cross-sectional cohort study

AIM

To explore the impact of the Omicron variant on maternal and neonatal outcomes.

DESIGN

Cross-sectional cohort study of women giving live birth in a single hospital in Shanghai in December 2022.

METHODS

Demographic characteristics, maternal and neonatal outcomes and laboratory testing results were retrieved from medical records. Propensity score matching was used to match COVID-19-positive and -negative women. Differential analysis was used to assess associations between COVID-19 and in-hospital maternal and neonatal outcomes.

RESULTS

A total of 1508 women were included, comprising 729 natural births, 741 caesarean sections and 38 forceps deliveries. After 1:1 matching, 310 clients were included for analysis with each 155 in COVID-19-positive and -negative groups. Higher maternal fever was found in all modes of delivery, and higher preterm birth and lower pH value of blood gas of the umbilical artery in the vaginal delivery subgroup (p < 0.05). Other maternal and neonatal outcomes showed no significant difference between COVID-19-positive and -negative clients.

Potassium-Based Dual-Ion Batteries Operating at -60 °C Enabled By Co-Intercalation Anode Chemistry

Battery performance at subzero is restricted by sluggish interfacial kinetics. To resolve this issue, potassium-based dual-ion batteries (K-DIBs) based on the polytriphenylamine (PTPAn) cathode with anion storage chemistry and the hydrogen titanate (HTO) anode with K+ /solvent co-intercalation mechanism are constructed. Both the PTPAn cathode and the HTO anode do not undergo the desolvation process, which can effectively accelerate the interfacial kinetics at subzero. As revealed by theoretical calculations and experimental analysis, the strong K+ /solvent binding energy in the dilute electrolyte, the charge shielding effect of the crystal water, and the uniform SEI layer with high content of the flexible organic species synergically promote HTO to undergo K+ /solvent co-intercalation behavior. The special co-intercalation mechanism and anion storage chemistry enable HTO||PTPAn K-DIBs with superior rate performance and cycle durability, maintaining a capacity retention of 94.1% after 6000 cycles at -40 °C and 91% after 1000 cycles at -60 °C. These results provide a step forward for achieving high-performance energy storage devices at low temperatures.

Epidemiololgical and etiological analysis of two clusters of severe fever with thrombocytopenia syndrome

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease, caused by severe fever with thrombocytopenia syndrome virus (SFTSV), which is primarily transmitted via tick bites. Clusters of SFTS caused by human-to-human transmission have been reported both at home and abroad, mainly focused on the transmission or exposure modes. However, the correlation between SFTS clusters and viral genotypes has not been investigated. This study mainly reported two clusters of SFTS in Xinyang City, Henan Province, from 2022 to 2023, discussed the possible route of person-to-person transmission of SFTSV infection and analyzed the association between SFTS clusters and virus genotypes. We found that two groups of SFTSV in two clusters were clustered separately into different genotypes through viral sequence analysis of 4 confirmed patients. We also performed phylogenetic analysis, after including SFTSV sequences obtained from SFTS clusters deposited in the GenBank. Three SFTSV genotypes have been reported among cases of human-to-human transmission, suggesting that the occurrence of SFTS clusters may not be related to SFTSV genotypes. This study provided genetic evidence for revealing the chain of human-to-human transmission of SFTS clusters, indicating that contact with patients' blood is an important transmission route of SFTSV. The findings laid the foundation for preventing and controlling human-to-human transmission of SFTS.

Synergistic Effect of 2-(Trifluoromethyl) Benzimidazole on the Stability and Performance of Perovskite Solar Cells

The quality of the perovskite active layer directly impacts the photovoltaic performance of perovskite solar cells (PSCs). Unfortunately, perovskite films produced through solution methods often have a significant number of defects on their surface, which lead to a substantial degradation in the performance of devices. For this reason, a multifunctional additive 2-(trifluoromethyl) benzimidazole (TFMBI) is introduced into perovskite films. Based on the Lewis acid/base coordination principle, the TFMBI double site cooperatively passivates surface defects, inhibiting carrier non-radiative recombination. Simultaneously, the hydrophobic solid group (-CF₃) of TFMBI covers the surface, establishing a moisture-oxygen barrier and improving the environmental stability of the devices. In consequence, the power conversion efficiency (PCE) of TFMBI-modified PSCs reached 23.16%, significantly higher than the pristine one with a PCE of 20.62%. Additionally, the unencapsulated target device retained 90.32% of its initial PCE even after being reserved in the air with a relative humidity of 20-30% for 60 days.

The spatial-temporal pattern of Japanese encephalitis and its influencing factors in Guangxi, China

Japanese encephalitis (JE) is a major global public health threat. Using Japanese encephalitis incidence data from 2004 to 2010 in Guangxi Province, China, this study comprehensively explored the driving forces and the interactive effects between environmental and social factors of Japanese encephalitis using the Geo-detector method. The results indicated that the incidence of Japanese encephalitis showed a fluctuating downward trend from 2004 to 2010. The onset of JE was seasonal, mainly concentrated in June-July, and highly aggregated in northwestern Guangxi. Among the factors associated with Japanese encephalitis, days with temperatures >30 °C, accumulated temperatures >25 °C, slope, the normalized difference vegetation index, the gross domestic product of tertiary industries, the gross domestic product of primary industries and the number of pigs slaughtered showed higher contributions to Japanese encephalitis incidence. An enhanced interactive effect was found between environmental and social factors, and the interaction between days with humidity levels >80% and the gross domestic product of tertiary industries had the greatest combined effect on JE. These findings enhanced the understanding of the combined effect of social and environmental factors on the incidence of Japanese encephalitis and could help improve Japanese encephalitis transmission control and prevention strategies.

High-Efficiency Carbon-based CsPbI2 Br Perovskite Solar Cells from Dual Direction Thermal Diffusion Treatment with Cadmium Halides

In recent years, carbon-based CsPbI₂ Br perovskite solar cells (PSCs) have attracted more attention due to their low cost and good stability. However, the power conversion efficiency (PCE) of carbon-based CsPbI₂ Br PSCs is still no more than 16%, because of the defects in CsPbI₂ Br or at the interface with the electron transport layer (ETL), as well as the energy level mismatch, which lead to the loss of energy, thus limiting PCE values. Herein, a series of cadmium halides are introduced, including CdCl₂ , CdBr₂ and CdI₂ for dual direction thermal diffusion treatment. Some Cd²⁺ ions thermally diffuse downward to passivate the defects inside or on the surface of SnO₂ ETL. Meanwhile, the energy level structure of SnO₂ ETL is adjusted, which is in favor of the transfer of electron carriers and blocking holes. On the other hand, part of Cd²⁺ and Cl^- ions thermally diffuse upward into the CsPbI₂ Br lattice to passivate crystal defects. Through dual direction thermal diffusion treatment by CdCl₂ , CdI₂ and CdBr₂ , the performance of devices has been significantly improved, and their PCE has been increased from 13.01% of the original device to 14.47%, 14.31%, and 13.46%, respectively. According to existing reports, 14.47% is one of the highest PCE of carbon-based CsPbI₂ Br PSCs with SnO₂ ETLs.

Potential distribution of three types of ephemeral plants under climate changes

BACKGROUND

Arid and semi-arid regions account for about 40% of the world's land surface area, and are the most sensitive areas to climate change, leading to a dramatic expansion of arid regions in recent decades. Ephemeral plants are crucial herbs in this area and are very sensitive to climate change, but it is still unclear which factors can determine the distribution of ephemeral plants and how the distribution of ephemeral plants responds to future climate change across the globe.

AIMS

Understanding the impact of climate change on ephemeral plant distribution is crucial for sustainable biodiversity conservation.

METHODS

This study explored the potential distribution of three types of ephemeral plants in arid and semi-arid regions (cold desert, hot desert, and deciduous forest) on a global scale using the MaxEnt software. We used species global occurrence data and 30 environmental factors in scientific collections.

RESULTS

Our results showed that (1) the average value of the area under the receiver operating curve (AUC) of each species was higher than 0.95, indicating that the MaxEnt model's simulation accuracy for each species was good; (2) distributions of cold desert and deciduous forest species were mainly determined by soil pH and annual mean temperature; the key factor that determines the distribution of hot desert species was precipitation of the driest month; and (3) the potential distribution of ephemeral plants in the cold desert was increased under one-third of climate scenarios; in the hot desert, the potential suitable distribution for Anastatica hierochuntica was decreased in more than half of the climate scenarios, but Trigonella arabica was increased in more than half of the climate scenarios. In deciduous forests, the ephemeral plant Crocus alatavicus decreased in nearly nine-tenths of climate scenarios, and Gagea filiformis was increased in 75% of climate scenarios.

CONCLUSIONS

The potential suitable distributions of ephemeral plants in the different ecosystems were closely related to their specific adaptation strategies. These results contribute to a comprehensive understanding of the potential distribution pattern of some ephemeral plants in arid and semi-arid ecosystems.

Holistically Optimizing Charge Carrier Dynamics Enables High-Performance Dye-Sensitized Solar Cells and Photodetectors

Charge carrier events across organic electronics are ubiquitous, and the derived optimization plays a crucial effect on improving the performance of organic electronics. Herein, a two-dimensional material (Ti₃C₂T_x) is incorporated into titanium dioxide (TiO₂) to impart the Ti₃C₂T_x/TiO₂ hybrid film enriched hydroxy group distribution, defect-negligible surface, upshifted work function, and enhanced conductivity yet electron mobility versus the pristine TiO₂ film. Therefore, intensified photon-harvesting ability, reduced charge carrier recombination, and efficient charge carrier collection are realized for dye-sensitized solar cells (DSSCs) based on the Ti₃C₂T_x/TiO₂ hybrid photoanode relative to control ones. Consequently, the modified DSSCs based on Z907 deliver superior efficiencies of 10.39 and 29.68% under 100 mW/cm² illumination and ∼1.9 mW/cm² dim light, respectively, being the highest values of Z907-based DSSCs. However, control devices only obtain lower efficiencies of 8.06 and 23.91% when undergoing the abovementioned illumination. On the other hand, the self-powered homologous photodetectors with the hybrid film as an electron-transporting layer present enhanced detectivity (1.69 × 10¹¹ Jones) and a shortened responsivity of 0.26 s versus that of control ones (1.39 × 10¹¹ Jones and 0.35 s). Our work implies that the Ti₃C₂T_x/TiO₂ hybrid film features high potential for improving the performance of organic electronics for its effect of holistically optimizing charge carrier dynamics.

Predictive capability of material screening by fast neutron activation analysis using laser-driven neutron sources

Bright, short-pulsed neutron beams from laser-driven neutron sources (LANSs) provide a new perspective on material screening via fast neutron activation analysis (FNAA). FNAA is a nondestructive technique for determining material elemental composition based on nuclear excitation by fast neutron bombardment and subsequent spectral analysis of prompt γ-rays emitted by the active nuclei. Our recent experiments and simulations have shown that activation analysis can be used in practice with modest neutron fluences on the order of 10⁵ n/cm², which is available with current laser technology. In addition, time-resolved γ-ray measurements combined with picosecond neutron probes from LANSs are effective in mitigating the issue of spectral interference between elements, enabling highly accurate screening of complex samples containing many elements. This paper describes the predictive capability of LANS-based activation analysis based on experimental demonstrations and spectral calculations with Monte Carlo simulations.

Surface Reconstruction and In Situ Formation of 2D Layer for Efficient and Stable 2D/3D Perovskite Solar Cells

The 2D/3D composite structure possesses both the excellent stability of 2D perovskite and the excellent performance of 3D perovskite, which recently have attracted special attention. Different from the popular isopropanol, a novel additive solvent-polypropylene glycol bis (2-aminopropyl ether) (A-PPG) is introduced here to dissolve excess PbI₂ and perovskite, and then reconstruct and in situ form the quasi-2D perovskite layer on 3D perovskite bulk. The lone electron pairs of the ether-oxygen and amino in A-PPG can form coordination bonds with Pb²⁺ . The introduction of A-PPG tunes the energy array of functional layers, passivates defects, and mitigates carrier nonradiative recombination. Consequently, the 2D/3D perovskite device exhibits a championship efficiency of 22.24% with a distinguished open-circuit voltage of 1.21 V (the thermodynamic limit of 1.30 V). Moreover, the 2D/3D device still maintains 90% of the original efficiency in the ambient atmosphere with a relative humidity of 30 ± 10% after 50 days.

Alkali Metal Fluoride-Modified Tin Oxide for n-i-p Planar Perovskite Solar Cells

The practical applications of perovskite solar cells (PSCs) are limited by further improvement of their stability and performance. Additive engineering and interface engineering are promising medicine to cure this stubborn disease. Herein, an alkali metal fluoride as an additive is introduced into the tin oxide (SnO₂) electron transport layer (ETL). The formation of coordination bonds of F^- ions with the oxygen vacancy of Sn⁴⁺ ions decreases the trap-state density and improves the electron mobility; the hydrogen bond interaction between the F ion and amine group (FA⁺) of perovskite inhibits the diffusion of organic cations and promotes perovskite (PVK) stability. Meanwhile, the alkali metal ions (K⁺, Rb⁺, and Cs⁺) permeated into PVK fill the organic cation vacancies and ameliorate the crystal quality of PVK films. Consequently, a SnO₂-based planar PSC exhibits a power conversion efficiency (PCE) of 20.24%, while the PSC modified by CsF achieves a PCE of 22.51%, accompanied by effective enhancement of stability and negligible hysteresis. The research results provide a typical example for low-cost and multifunctional additives in high-performance PSCs.

Enhancing efficiency of perovskite solar cells from surface passivation of Co2+ doped CuGaO2 nanocrystals

Before completely applying inorganic materials as hole transport materials (HTM) for perovskite solar cells (PSCs), modifying devices with inorganic oxides that have the potential as inorganic hole transporters is an effective way to improve device performance and stability. Co²⁺ doped CuGaO₂ nanocrystals (Co-CuGaO₂ NCs) with sizes about 20 nm are synthesized by hydrothermal method and used for surface passivation at the interface of perovskite (PVK)/2,2',7,7'-Tetrakis[N,N-di (4-methoxyphenyl) amino]-9,9'-spirobifluorene (spiroOMeTAD). Co-CuGaO₂ NCs have a larger bandgap with lower valance band compared with spiroOMeTAD, which is more beneficial to the conduction of holes and the blocking of electrons. Furthermore, the Co-CuGaO₂ has a lower valance band energy compared with the original CuGaO₂, which reduces the energy gap between Co-CuGaO₂ and PVK. Co-CuGaO₂ NCs fully cover the upper surface of PVK, which helps prevent direct contact between PVK and oxygen and moisture. The Co-CuGaO₂ NCs surface passivation also gives better hole transport as revealed by the ultraviolet photoelectron spectroscopy (UPS), steady-state photoluminescence (PL), and time-resolved photoluminescence (TRPL) data. When the concentration of Co-CuGaO₂ NCs solution is set to 7.5 mg mL^-1, the device exhibits a best PCE of 20.39% and maintains 84.34% of the initial power conversion efficiency (PCE) after stored 30 days under air atmosphere with 15 ± 5% humidity.

n-type absorber by Cd2+ doping achieves high-performance carbon-based CsPbIBr2 perovskite solar cells

High efficiency and stability have long been the key issues faced by perovskite solar cells (PSCs). It is found that the CsPbIBr₂ all-inorganic perovskite has a suitable band gap and satisfactory stability, so it has attracted much attention. However, the many defects in the CsPbIBr₂ film are one of the main problems hindering the improvement of power conversion efficiency (PCE) of the CsPbIBr₂ PSCs. The substitution of trace impurities is undoubtedly a simple, cost-effective and efficient strategy. In this work, an appropriate amount of Cd²⁺ (1.0% mol of Pb²⁺) is added into the CsPbIBr₂ precursor solution to fabricate high quality CsPbIBr₂ film with improved crystallinity, reduced trap density, suppressed photo-generated carrier recombination, displayed n-type doping and optimized energy level alignment. The corresponding carbon-based all-inorganic Cd²⁺-doped CsPbIBr₂ PSCs achieve a maximum PCE of 10.63% with a high open circuit voltage (V_OC) of 1.324 V, which are much higher than those of the control one with a PCE of 8.48% and an V_OC of 1.235 V. The unencapsulated device can still retain more than 92% of the initial PCE when stored at ambient atmosphere (25 °C, relative humidity about 30%) for 40 days.

Marked Passivation Effect of Naphthalene-1,8-Dicarboximides in High-Performance Perovskite Solar Cells

As game-changers in the photovoltaic community, perovskite solar cells are making unprecedented progress while still facing grand challenges such as improving lifetime without impairing efficiency. Herein, two structurally alike polyaromatic molecules based on naphthalene-1,8-dicarboximide (NMI) and perylene-3,4-dicarboximide (PMI) with different molecular dipoles are applied to tackle this issue. Contrasting the electronically pull-pull cyanide-substituted PMI (9CN-PMI) with only Lewis-base groups, the push-pull 4-hydroxybiphenyl-substituted NMI (4OH-NMI) with both protonic and Lewis-base groups can provide better chemical passivation for both shallow- and deep-level defects. Moreover, combined theoretical and experimental studies show that the 4OH-NMI can bind more firmly with perovskite and the polyaromatic backbones create benign midgap states in the excited perovskite to suppress the damage by superoxide anions (energetic passivation). The polar and protonic nature of 4OH-NMI facilitates band alignment and regulates the viscosity of the precursor solution for thicker perovskite films with better morphology. Consequently, the 4OH-NMI-passivated perovskite films exhibit reduced grain boundaries and nearly three-times lower defect density, boosting the device efficiency to 23.7%. A more effective design of the passivator for perovskites with multi-passivation mechanisms is provided in this study.

High-Efficiency, Low-Hysteresis Planar Perovskite Solar Cells by Inserting the NaBr Interlayer

With great research potential, the perovskite solar cells (PSCs) have been well developed in recent years, but there are still some urgent issues like efficiency and hysteresis defects that severely limit their commercialization. Interface modification is a significant measure to reduce defects and promote performance. In the article, an easy and effective strategy of modifying the electron transport layer (ETL) with NaBr is proposed to improve efficiency and reduce hysteresis. The charge carrier dynamics can be greatly optimized by diffusing NaBr on the ETL. The efficiency of the NaBr coated device can achieve 21.16%, which is extremely higher than the control one and shows low hysteresis behavior with a hysteresis index reduced from 0.135 to 0.025. The results indicate that the NaBr modification provides a novel strategy for preparing PSCs with high efficiency and low hysteresis.

A dye-sensitized solar cell based on magnetic CoP@FeP4@Carbon composite counter electrode generated an efficiency of 9.88%

We present a facile systematic hydrothermal-phosphorization processing procedure for in situ growth of CoP@FeP4 on carbon paper, which could be used efficient counter electrodes in DSSCs with enhanced efficiency of 9.88%, much higher than that of the Pt (7.49%) CE.

Additive Engineering by Bifunctional Guanidine Sulfamate for Highly Efficient and Stable Perovskites Solar Cells

High efficiency and good stability are the challenges for perovskite solar cells (PSCs) toward commercialization. However, the intrinsic high defect density and internal nonradiative recombination of perovskite (PVK) limit its development. In this work, a facile additive strategy is devised by introducing bifunctional guanidine sulfamate (GuaSM; CH₆ N₃ ⁺ , Gua⁺ ; H₂ N-SO₃ ^- , SM^- ) into PVK. The size of Gua⁺ ion is suitable with Pb(BrI)₂ cavity relatively, so it can participate in the formation of low-dimensional PVK when mixed with Pb(BrI)₂ . The O and N atoms of SM^- can coordinate with Pb²⁺ . The synergistic effect of the anions and cations effectively reduces the trap density and the recombination in PVK, so that it can improve the efficiency and stability of PSCs. At an optimal concentration of GuaSM (2 mol%), the PSC presents a champion power conversion efficiency of 21.66% and a remarkably improved stability and hysteresis. The results provide a novel strategy for highly efficient and stable PSCs by bifunctional additive.

Strong electron acceptor additive based spiro-OMeTAD for high-performance and hysteresis-less planar perovskite solar cells

As the most popular hole-transporting material (HTM), spiro-OMeTAD has been extensively applied in perovskite solar cells (PSCs). Unluckily, the pristine spiro-OMeTAD film has inferior conductivity and hole mobility, thus limiting its potential for application in high-performance PSCs. To ameliorate the electrical characteristics of spiro-OMeTAD, we employ 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as a strong electron acceptor into spiro-OMeTAD in PSCs. The incorporation of DDQ with spiro-OMeTAD not only improves the conductivity and the Fermi energy level, but also reduces the trap states and nonradiative recombination, which accounts for the remarkable enhancement in both the fill factor (FF) and open-circuit voltage (V_OC) of PSCs. Consequently, the champion PSC with DDQ doped hole transport layer (HTL) generates a boosted power conversion efficiency (PCE) of 21.16% with an FF of 0.796 and a V_OC of 1.16 V. Remarkably, DDQ modified devices exhibit superb device stability, as well as mitigated hysteresis. This study provides a facile and viable strategy for dopant engineering of HTL to realize highly efficient PSCs.

A perovskite solar cell with DDQ doped spiro-OMeTAD HTL delivers a champion power conversion efficiency of 21.16%.

Defect Control Strategy by Bifunctional Thioacetamide at Low Temperature for Highly Efficient Planar Perovskite Solar Cells

Titania (TiO₂) has wide applications in the realm of perovskite solar cells (PSCs). Because high-temperature processing severely limits the application of flexible and tandem devices, it is significant to develop a high-quality electron-transport layer (ETL) by low-temperature processing. Here, we design a new strategy by introducing a bifunctional molecule (thioacetamide, TAA) in the TiO₂ ETL. During the low-temperature annealing, the N and S atoms in TAA can bond with the Ti atom in the ETL and the Pb atom in the perovskite (PVK) layer, respectively. The formation of coordinate bonds is beneficial to increase the crystallinity and reduce the roughness of TiO₂ ETLs and PVK layers, which effectively passivate the defects. Meanwhile, the energy level matching between the ETL and PVK is optimized. The structure characterization and electrochemical measurement demonstrate the design. Compared with precursor doping, surface spin-coating is a more effective method for introducing TAA into TiO₂. Significantly, the PSC based on the surface spin-coated TAA TiO₂ ETL achieves the best power conversion efficiency (PCE) of 21.17%. Nevertheless, the PSC fabricated with the pristine TiO₂ ETL offers a PCE of 19.52% under the same conditions. The results demonstrate a novel method for optimizing the properties of PSCs.

Highly Efficient CsPbBr3 Planar Perovskite Solar Cells via Additive Engineering with NH4SCN

Improving stability is a major aspect for commercial application of perovskite solar cells (PSCs). The all-inorganic CsPbBr₃ perovskite material has been proven to have excellent stability. However, the CsPbBr₃ film has a small range of light absorption and serious charge recombination at the interface or inside the device, so the power conversion efficiency is still lower than that of the organic-inorganic hybrid one. Here, we successfully fabricate high-quality CsPbBr₃ films via additive engineering with NH₄SCN. By incorporating NH₄⁺ and pseudo-halide ion SCN^- into the precursor solution, a smooth and dense CsPbBr₃ film with good crystallinity and low trap state density can be obtained. At the same time, the results of a series of photoluminescence and electrochemical analyses including electrical impedance spectroscopy, space-charge limited current method, Mott-Schottky data, and so on reveal that the NH₄SCN additive can greatly reduce the trap state density of the CsPbBr₃ film and also effectively inhibit interface recombination and promote charge transport in the CsPbBr₃ planar PSC. Finally, the CsPbBr₃ planar PSC prepared with a molar ratio of 1.5% NH₄SCN achieves a champion efficiency of 8.47%, higher than that of the pure one (7.12%).

Suppressing Vacancy Defects and Grain Boundaries via Ostwald Ripening for High-Performance and Stable Perovskite Solar Cells

As one kind of promising next-generation photovoltaic devices, perovskite solar cells (PVSCs) have experienced unprecedented rapid growth in device performance over the past few years. However, the practical applications of PVSCs require much improved device long-term stability and performance, and internal defects and external humidity sensitivity are two key limitation need to be overcome. Here, gadolinium fluoride (GdF₃ ) is added into perovskite precursor as a redox shuttle and growth-assist; meanwhile, aminobutanol vapor is used for Ostwald ripening in the formation of the perovskite layer. Consequently, a high-quality perovskite film with large grain size and few grain boundaries is obtained, resulting in the reduction of trap state density and carrier recombination. As a result, a power conversion efficiency of 21.21% is achieved with superior stability and negligible hysteresis.

High-Performance and Hysteresis-Free Perovskite Solar Cells Based on Rare-Earth-Doped SnO2 Mesoporous Scaffold

Tin oxide (SnO₂), as electron transport material to substitute titanium oxide (TiO₂) in perovskite solar cells (PSCs), has aroused wide interests. However, the performance of the PSCs based on SnO₂ is still hard to compete with the TiO₂-based devices. Herein, a novel strategy is designed to enhance the photovoltaic performance and long-term stability of PSCs by integrating rare-earth ions Ln³⁺ (Sc³⁺, Y³⁺, La³⁺) with SnO₂ nanospheres as mesoporous scaffold. The doping of Ln promotes the formation of dense and large-sized perovskite crystals, which facilitate interfacial contact of electron transport layer/perovskite layer and improve charge transport dynamics. Ln dopant optimizes the energy level of perovskite layer, reduces the charge transport resistance, and mitigates the trap state density. As a result, the optimized mesoporous PSC achieves a champion power conversion efficiency (PCE) of 20.63% without hysteresis, while the undoped PSC obtains an efficiency of 19.01%. The investigation demonstrates that the rare-earth doping is low-cost and effective method to improve the photovoltaic performance of SnO₂-based PSCs.

Assessment of the Hemodynamics of Autogenous Arteriovenous Fistulas With 4D Phase Contrast-Based Flow Quantification MRI in Dialysis Patients

BACKGROUND

Regular monitoring of autogenous arteriovenous fistulas (AVFs) for hemodialysis patients has importance. Hence, 4D flow MRI may be an alternative for assessing the hemodynamics of AVFs.

PURPOSE

To compare the hemodynamics of AVFs using Doppler ultrasound (DUS) and 4D-MRI in renal dialysis patients.

STUDY TYPE

Case-control study from October 2017 to April 2018.

POPULATION

Fifty patients (age [range] = 59.52 [39-71] years) with AVFs were included.

FIELD STRENGTH/SEQUENCE

Black-blood MRI and 4D flow MRI at 3.0T and AVF ultrasonography were also performed.

ASSESSMENT

The hemodynamics acquired from 4D flow MRI and ultrasonography by two radiologists were compared. The AVF anatomy was described through an examination of the black-blood MRI.

STATISTICAL TESTS

The consistency of AVF anatomy and hemodynamics and the consistency of the hemodynamics of AVFs from 4D flow MRI and ultrasound were analyzed by paired t-tests. The morphological parameters of AVFs acquired from black-blood MRI were used for a Pearson correlation analysis with the hemodynamic parameters obtained from 4D flow MRI data.

RESULTS

The consistency of the morphological and hemodynamic parameters measured from MRI by the two radiologists was good (all P < 0.01). The velocities and flow volumes from the 4D flow MRI and vascular ultrasound of AVFs were in moderate agreement (all P < 0.05, r = 0.292-0.569), except for the peak flow velocity at the anastomosis (P = 0.366, r = -0.078). The flow volume and WSS near the anastomotic site were closely related to the morphology of the AVFs (all P < 0.05). The hemodynamics of the complications group were significantly different from those of patients without any complications (normal patients group) (all P < 0.01).

DATA CONCLUSION

Compared with ultrasonography, 4D flow MRI is a promising technique to noninvasively estimate the AVF hemodynamics of renal dialysis patients.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:1272-1280.

Breviscapine Induces Breast Cancer Cell Cycle Arrest and Apoptosis by Modulating the Jak-Stat Pathway

The aim of this study was to investigate the effects and possible mechanisms of breviscapine arrest in the development of breast cancer cells. Cell viability, cycle arrest, and apoptosis were measured using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazoliumbromide assay and flow cytometry in MCF-7 cells treated with increasing concentrations of breviscapine. In addition, the expression level of cyclin D1, p21, cleaved caspase-3, and poly ADP-ribose polymerase, p-Janus kinase 2 and p-signal transducers and activators of transcription 3 was analyzed using western blot assay. The results showed that breviscapine suppressed cell viability and induced apoptosis in MCF-7 cells in a dose-dependent fashion. Breviscapine also increased MCF-7 cell number in the G1 phase and decreased that in the S phase. Moreover, cyclin D1, p-JAK2/JAK2, and p-STAT3/STAT3 expression levels were down-regulated, while p21, cleaved caspase-3, and poly ADP-ribose polymerase expression levels were up-regulated in breviscapine-treated MCF-7 cells. In conclusion, breviscapine regulates breast cancer viability, cell cycle arrest, and apoptosis in a concentration-dependent manner by modulating the JAK-STAT pathway.

Toward Highly Reproducible, Efficient, and Stable Perovskite Solar Cells via Interface Engineering with CoO Nanoplates

It is well-known that solution-processed polycrystalline perovskite films show a high density of parasitic traps and the defects mainly exist at grain boundaries and surfaces of polycrystal perovskite films, which would limit potential device performance by triggering the undesired recombination and impair device long-term stability by accelerating the degradation of perovskite films. In this regard, defect passivation is highly desirable for achieving efficient and stable perovskite solar cells (PSCs). Here, we report the fabrication of highly reproducible, efficient, and stable PSCs via interface engineering with CoO nanoplates. When a suitable concentration of CoO nanoplates solution is spin-coated on perovskite film, a discontinuous CoO nanoplates modified layer is obtained, which is advantageous to achieving highly photovoltaic performance of the device because the uncovered perovskite crystalline grains can guarantee the unobstructed transport of holes from perovskite layers to hole transport layers. Furthermore, the hydrophobic oleylamine ligands capped CoO nanoplates are well filled in the boundaries of perovskite crystalline grains to effectively passivate the trap states, suppress dark recombination, and enhance moisture-resistance. These benefits are propitious to achieving a 20.72% champion efficiency and a 20.20% steady-state efficiency of the devices with good reproducibility and stability.

[Comparisons of prevalence and clinical and environmental characteristics between Tibetan and Han Women with polycystic ovarian syndrome in Tibetan Plateau]

Objective: By the preliminary comparison study on the constituent ratio and clinical characteristics of polycystic ovary syndrome (PCOS) in Tibetan and Han women in Tibetan Plateau, we aimed to find the relevance of its pathogenic factors, and to guide the treatment of PCOS in the plateau region and improve the prognosis. Methods: The general situation and clinical data of 165 patients who were diagnosed with PCOS from December 1, 2015 to November 30, 2016 in the Department of Obstetrics and Gynecology of the People's Hospital of Tibet Autonomous Region were analyzed retrospectively. The prevalence of PCOS among Tibetan and Han women in Tibetan Plateau were compared. Results: (1) A total of 1 520 patients were treated in the Tibet Autonomous Region People's Hospital gynecological endocrinology clinics in one year (Tibetan 865 cases, Han 617 cases, other ethnic groups 38 cases), of which patients with PCOS accounted for 10.9% (165/1520). (2) The incidence of Tibetan PCOS patients with oligomenorrhea, infertility, amenorrhea, acne, hairy, LH/FSH inverted, overweight (BMI≥24), and waist circumference >80 cm were 21.2% (35/165), 20.6% (34/165), 16.4% (27/165), 28.5% (47/165), 17% (28/165), 38.2% (63/165), 23.6% (39/165), and 36.4% (60/165), respectively. The incidence of Han PCOS patients with oligomenorrhea, infertility, amenorrhea, acne, hairy, LH/FSH inverted, overweight (BMI≥24), and waist circumference >80 cm were 7.9% (13/165), 10.3% (17/165), 9.1% (15/165), 15.2% (25/165), 9.7% (16/165), 14.5% (24/165), 10.9% (18/165) and 19.4% (32/165), respectively. The proportion of high testosterone in Tibetan PCOS patients was higher than that in Han PCOS patients with statistically significant. (3) The chief complaint of Tibetan PCOS patients were oligomenorrhea and infertility, and the chief complaint of Han PCOS patients were infertility and amenorrhea. (4) The constituent ratio of outpatient clinics in Nyingchi who were with PCOS at an average elevation of about 3 000 meters in the Tibetan Plateau was 7.9% (13/165), and the average constituent ratio in Lhasa, Xigatse and Nagqu over 3 500 meters above sea level was 35.8% (59/165), 16.9% (28/165) and 15.8% (26/165), respectively. Conclusion: The prevalence of PCOS in Tibetan areas is slightly higher than that in the international community. The clinical manifestations of Tibetan patients with PCOS are significantly different from those of Han patients with PCOS. The higher the altitude, the higher the incidence of PCOS.

Characterization of urinary biomarkers and their relevant mechanisms of zoledronate-induced nephrotoxicity using rats and HK-2 cells

The aim of this study was to identify biomarkers of zoledronate-induced nephrotoxicity and to further characterize the mechanisms underlying this process by analyzing urinary metabolites. Twenty-four rats were randomly divided into four groups containing four (two control groups) or eight rats (two zoledronate groups) per group. The rats were injected intravenously with saline or zoledronate (3 mg/kg) singly (single, 3 weeks) or repeatedly eight times (3 weeks/time, 24 weeks). Serum blood urea nitrogen, serum creatinine, creatinine clearance, and kidney injury observed by hematoxylin and eosin and immunohistochemical staining were changed only in the repeated zoledronate group (3 mg/kg, 3 weeks/time, 24 weeks). Urinary levels of S-adenosylmethionine, S-adenosylhomocysteine, l-cystathionine, l-γ-glutamylcysteine, and glutathione related to glutathione metabolism and fumaric acid and succinic acid related to the tricarboxylic acid cycle in the zoledronate-treated group (3 mg/kg, 3 weeks/time, 24 weeks) were significantly lower than those in the control group, suggesting that zoledronate may cause cellular oxidative stress. Besides, urinary levels of uracil and uridine related to pyrimidine metabolism also decreased after zoledronate treatment (3 mg/kg, 3 weeks/time, 24 weeks), while the levels of hypoxanthine related to purine metabolism, histamine related to histamine metabolism, and several amino acids were significantly increased. Moreover, zoledronate-induced enhanced oxidative stress and histamine overproduction were confirmed by reactive oxygen species (ROS) and histamine measurement in a human proximal tubular cell line. Taken together, zoledronate-induced nephrotoxicity may be attributed to it inducing perturbations in glutathione biosynthesis and the tricarboxylic acid cycle, further causing ROS overproduction, oxidative stress, and cellular inflammation, thereby leading to nephrotoxicity.

Annealing-Free Cr2 O3 Electron-Selective Layer for Efficient Hybrid Perovskite Solar Cells

The electron-selective layer (ESL) plays a pivotal role in the performance of perovskite solar cells (PSCs). In this study, amorphous dispersible chromium oxide (Cr₂ O₃ ) nanosheets are synthesized by a facile solvothermal reaction, and a Cr₂ O₃ ESL is prepared by spin-coating Cr₂ O₃ ink on fluorine-doped tin oxide substrates without need for further annealing. By using Cr₂ O₃ as the electron-selective layer and Cs_0.05 (MA_0.17 FA_0.83 )_0.95 Pb(I_0.83 Br_0.17 )₃ as the light-absorption layer, a planar hybrid perovskite solar cell is fabricated. The spin-coating speed is optimized, the structure and morphology of samples are observed, the photoelectrical properties of ESLs are characterized, and the photovoltaic behaviors of devices are measured. Results show that the as-prepared Cr₂ O₃ layer has high optical transmittance and superb electron extraction and carrier transport property. The planar hybrid PSC based on the optimized Cr₂ O₃ ESL achieves a power conversion efficiency of 16.23 %, which is comparable to devices based on a conventional high-temperature-calcined TiO₂ ESL. These results demonstrate a low-cost and facile route to highly effective perovskite solar cells.

Cadmium sulfide as an efficient electron transport material for inverted planar perovskite solar cells

Dispersible cadmium sulfide (CdS) nanoparticles are synthesized by a facile solvothermal reaction and are used for the first time as an electron transport layer (ETL) in inverted planar perovskite solar cells.

[Intentional replantation for the treatment of palatal radicular groove with endo-periodontal lesion in the maxillary lateral incisor: a case report]

Palatal radicular groove leads to severe endo-periodontal lesion in lateral incisors. The groove occurs on the labial and lingual root surfaces, while the localized periodontal pocket develops along the lingual groove length. The complicated root canal system, extensively destroyed bone lamella, and persistent fistula pose a challenge for root canal therapy, tooth retention, and thorough infection control inside and outside of the root canal. Combining microscopic root canal therapy with intentional replantation and nano-biomaterial application facilitates infection control, tooth retention, and formation of newly periodontal attachment.

An alternative laser driven photodissociation mechanism of pyrrole via πσ*1∕S0 conical intersection

A first principles quantum dynamics study of N-H photodissociation of pyrrole on the S₀-¹πσ^*(A21) coupled electronic states is carried out with the aid of an optimally designed UV-laser pulse. A new photodissociation path, as compared to the conventional barrier crossing on the πσ*1 state, opens up upon electronic transitions under the influence of pump-dump laser pulses, which efficiently populate both the dissociation channels. The interplay of electronic transitions due both to vibronic coupling and the laser pulse is observed in the control mechanism and discussed in detail. The proposed control mechanism seems to be robust, and not discussed in the literature so far, and is expected to trigger future experiments on the πσ*1 photochemistry of molecules of chemical and biological importance. The design of the optimal pulses and their application to enhance the overall dissociation probability is carried out within the framework of optimal control theory. The quantum dynamics of the system in the presence of pulse is treated by solving the time-dependent Schrödinger equation in the semi-classical dipole approximation.

Modulated CH3NH3PbI3-xBrx film for efficient perovskite solar cells exceeding 18

The organic-inorganic lead halide perovskite layer is a crucial factor for the high performance perovskite solar cell (PSC). We introduce CH₃NH₃Br in the precursor solution to prepare CH₃NH₃PbI_3−xBr_x hybrid perovskite, and an uniform perovskite layer with improved crystallinity and apparent grain contour is obtained, resulting in the significant improvement of photovoltaic performance of PSCs. The effects of CH₃NH₃Br on the perovskite morphology, crystallinity, absorption property, charge carrier dynamics and device characteristics are discussed, and the improvement of open circuit voltage of the device depended on Br doping is confirmed. Based on above, the device based on CH₃NH₃PbI_2.86Br_0.14 exhibits a champion power conversion efficiency (PCE) of 18.02%. This study represents an efficient method for high-performance perovskite solar cell by modulating CH₃NH₃PbI_3−xBr_x film.

Counter electrodes in dye-sensitized solar cells

This article panoramically reviews the counter electrodes in dye-sensitized solar cells, which is of great significance for the development of photovoltaic and photoelectric devices.

An in situ polymerized PEDOT/Fe3O4 composite as a Pt-free counter electrode for highly efficient dye sensitized solar cells

PEDOT/Fe₃O₄ hybrid is in situ polymerized and used as Pt-free counter electrode in dye-sensitized solar cell. Owing to large active area and low charge transfer resistance for the hybrid, the cell achieves a high power conversion efficiency of 8.69%.

Effect of nano structures on the nucleus wetting modes during water vapour condensation: from individual groove to nano-array surface

The geometrical structures of surfaces are important to the formation and growth of nuclei during water vapour condensation. Nucleus wetting modes on grooved surfaces are determined by the intrinsic contact angle and the cross sectional angle.

TiO2 quantum dots as superb compact block layers for high-performance CH3NH3PbI3 perovskite solar cells with an efficiency of 16.97

A compact TiO(2) layer is crucial to achieve high-efficiency perovskite solar cells. In this study, we developed a facile, low-cost and efficient method to fabricate a pinhole-free and ultrathin blocking layer based on highly crystallized TiO(2) quantum dots (QDs) with an average diameter of 3.6 nm. The surface morphology of the blocking layer and the photoelectric performance of the perovskite solar cells were investigated by spin-coating with three different materials: colloidal TiO(2) QDs, titanium precursor solution, and aqueous TiCl(4). Among these three treatments, the perovskite solar cell based on the TiO(2) QD compact layer offered the highest power conversion efficiency (PCE) of 16.97% with a photocurrent density of 22.48 mA cm(-2), a photovoltage of 1.063 V and a fill factor of 0.71. The enhancement of PCE mainly stems from the small series resistance and the large shunt resistance of the TiO(2) QD layer.