Promoting Ruddlesden-Popper Perovskite Formation by Tailoring Spacer Intramolecular Interaction for Efficient and Stable Solar Cells.

Low-dimensional Ruddlesden-Popper phase (LDRP) perovskites are widely studied in the field of photovoltaics due to their tunable energy-band properties, enhanced photostability, and improved environmental stability compared to the 3D perovskites. However, the insulating spacers with weak intramolecular interaction used in LDRP materials limit the out-of-plane charge transport, leading to poor device performance of LDRP perovskite solar cells (PSCs). Here, a functional ligand, 3-guanidinopropanoic acid (GPA), which is capable of forming strong intramolecular hydrogen bonds through the carboxylic acid group, is employed as an organic spacer for LDRP PSCs. Owing to the strong interaction between GPA molecules, high-quality LDRP (GPA)2(MA)n-1PbnI3n+1 film with promoted formation of n = 5 phase, improved crystallinity, preferential vertical growth orientations, reduced trap-state density, and prolonged carrier lifetime is achieved using GPAI as the dimensionality regulator compared to butylamine hydroiodide (BAI). As a result, GPA-based LDRP PSC exhibits a champion power conversion efficiency of 18.16% that is much superior to the BA-based LDRP PSC (15.43%). Importantly, the optimized GPA-based LDRP PSCs without encapsulation show enhanced illumination, thermal, storage, and humidity stability compared to BA-based ones. This work provides new insights into producing high n value LDRP films and their efficient and stable PSCs.

Influence of Organic-Cation Defects on Optoelectronic Properties of ASnI3 Perovskites A=HC(NH2 )2 , CH3 NH3.

Tin organic-inorganic halide perovskites (tin OIHPs) possess a desirable band gap and their power conversion efficiency (PCE) has reached 14 %. A commonly held view is that the organic cations in tin OIHPs would have little impact on the optoelectronic properties. Herein, we show that the defective organic cations with randomly dynamic characteristics can have marked effect on optoelectronic properties of the tin OIHPs. Hydrogen vacancies originated from the proton dissociation from FA [HC(NH2 )2 ] in FASnI3 can induce deep transition levels in the band gap but yield relatively small nonradiative recombination coefficients of 10-15  cm3 s-1 , whereas those from MA (CH3 NH3 ) in MASnI3 can yield much larger nonradiative recombination coefficients of 10-11  cm3 s-1 . Additional insight into the "defect tolerance" is gained by disentangling the correlations between dynamic rotation of organic cations and charge-carrier dynamics.

Dynamic Stability of Copper Single-Atom Catalysts under Working Conditions.

The long-term stability of single-atom catalysts is a major factor affecting their large-scale commercial application. How to evaluate the dynamic stability of single-atom catalysts under working conditions is still lacking. Here, taking a single copper atom embedded in N-doped graphene as an example, the "constant-potential hybrid-solvation dynamic model" is used to evaluate the reversible transformation between copper single atoms and clusters under realistic reaction conditions. It is revealed that the adsorption of H is a vital driving force for the leaching of the Cu single atom from the catalyst surface. The more negative the electrode potential, the stronger the adsorption of H. As a result, the competitive hydrogen evolution reaction is inhibited, and Cu-N bonds are weakened, resulting in some Cu atoms being tethered on the catalyst surface and some being dissolved in the aqueous solution. The collision of the Cu atoms in the two states forms a transient Cu cluster structure as a true catalytic active site to promote CO2 reduction to ethanol. As the applied potential is released or switched to a positive value, hydroxyl radicals (OH•) play a dominant role in the oxidation process of the Cu cluster, and then Cu returns to the initial atomic dispersion state by redeposition, completing the reconstruction cycle of the copper catalyst. Our work provides a fundamental understanding of the dynamic stability of Cu single-atom catalysts under working conditions at the atomic level and calls for a reassessment of the stability of currently reported single-atom catalysts considering realistic reaction conditions.

N-Heterocyclic Carbene-Promoted [4+2] Annulation of α-Chloro Hydrazones with α-Chloro Aliphatic Aldehydes to Access Enantioenriched Dihydropyridazinones.

An expeditious protocol for the assembly of chiral 4,5-dihydropyridazin-3(2H)-ones from α-chloro hydrazones and α-chloro aliphatic aldehydes via N-heterocyclic carbene (NHC) catalysis is outlined. These in situ-generated 1,2-diaza-1,3-dienes undergo asymmetric [4+2] annulation with NHC-bound enolates to afford the desired products bearing a stereogenic center at the C4 position. The notable features of this approach include good to excellent enantioselectivities, high functional group tolerance, mild reaction conditions, simple operating procedures, and compatibility with gram-scale synthesis.

N-Heterocyclic Carbene-Catalyzed Stereoselective [3 + 2] Cycloaddition of N,N'-Cyclic Azomethine Imines with Aryl Acetaldehydes.

A highly stereoselective [3 + 2] cycloaddition reaction of N,N'-cyclic azomethine imines with aryl acetaldehydes enabled by a chiral N-heterocyclic carbene catalyst is accomplished, giving efficient access to a plethora of enantioenriched N,N'-bicyclic pyrazolidinones featuring aromatic substituents at the C2 position. The current strategy can be directly conducted on a gram scale, and the product could be further reduced to bicyclic pyrazolidine without loss of enantiopurity.

Efficient dehydrative alkylation of thiols with alcohols catalyzed by alkyl halides.

Alcohols can be efficiently converted into the useful thioethers by a transition metal- and base-free dehydrative S-alkylation reaction with thiols or disulfides by employing alkyl halides as the effective catalyst. This simple and efficient method is a green and practical way for the preparation of thioethers, as it tolerates a wide range of substrates such as aryl and alkyl thiols, as well as benzylic, allylic, secondary, tertiary, and even the less reactive aliphatic alcohols.

Dynamics of carbon monoxide dissociation on Co(112[combining macron]0).

The dissociative chemisorption dynamics of CO on rigid Co(112[combining macron]0) is investigated using a quasi-classical trajectory method on a new global six-dimensional potential energy surface (PES). The PES is fit using a neural network method to represent 24 630 density functional energies in various configurations. The reaction path features deep chemisorption wells and a late barrier for dissociation, agreeing well with previous calculations. The activation energy for dissociation ranges from 0.1 eV at the hollow site to 2.46 eV on the top site, indicating a highly corrugated PES. Effects of the incidence energy of the impinging molecule, its initial orientation, vibrational and rotational excitations, and site specificity are examined. Despite the presence of a low barrier, the initial dissociation probability is very small, even at high incident energies, as a large percentage of trajectories is either trapped or desorbed back to the gas phase. The low reactivity is attributed to inefficient energy transfer into the dissociation reaction coordinate in the chemisorption well where thermal equilibrium is not reached. This system underscores the importance of dynamics in understanding reactions at gas-surface interfaces and in kinetic modeling of catalytic processes.

Smoking, Hypertension, and Their Combined Effect on Ischemic Stroke Incidence: A Prospective Study among Inner Mongolians in China.

OBJECTIVE: We intended to investigate the combined effect of smoking and hypertension on ischemic stroke incidence based on a 10-year prospective study among Inner Mongolians in China. METHODS: A prospective cohort study from June 2003 to July 2012 was conducted among 2589 participants aged 20 years and older from Inner Mongolia, China. We categorized the participants into 4 subgroups according to the status of smoking and hypertension. The cumulative incidence rates of ischemic stroke among the 4 subgroups were estimated using Kaplan-Meier curves and compared by log-rank test. Cox proportional hazard model was used to compute hazard ratios of ischemic stroke across the 4 subgroups after adjusting for important confounding factors. RESULTS: The cumulative incidence rates of ischemic stroke were .85%, 2.05%, 3.19%, and 8.14% among non-hypertension/non-smokers, non-hypertension/smokers, hypertension/non-smokers, and hypertension/smokers, respectively. The multivariable-adjusted hazard ratios [95% confidence intervals] of ischemic stroke for hypertension and smoking were 1.84 [1.05-3.23] and 1.89 [1.11-3.22], respectively. The hazard ratios [95% confidence intervals] of ischemic stroke for non-hypertension/smokers, hypertension/non-smokers, and hypertension/smokers were 1.37 [.56-3.33], 1.34 [.54-3.29], and 2.93 [1.26-6.83], respectively, compared with the non-hypertension/non-smokers. Significant interaction was detected between smoking and hypertension on the risk of ischemic stroke. CONCLUSIONS: Our study indicated that participants with coexistence of smoking and hypertension were at the highest risk for ischemic stroke. There was a significant interaction between smoking and hypertension on the risk of ischemic stroke.

Probing the reactivity of microhydrated α-nucleophile in the anionic gas-phase S(N)2 reaction.

To probe the kinetic performance of microsolvated α-nucleophile, the G2(+)M calculations were carried out for the gas-phase S(N)2 reactions of monohydrated and dihydrated α-oxy-nucleophiles XO(-)(H2O)(n = 1,2) (X = HO, CH3O, F, Cl, Br), and α-sulfur-nucleophile, HSS(-)(H2O)(n = 1,2), toward CH3Cl. We compared the reactivities of hydrated α-nucleophiles to those of hydrated normal nucleophiles. Our calculations show that the α-effect of monohydrated and dihydrated α-oxy-nucleophiles will become weaker than those of unhydrated ones if we apply a plot of activation barrier as a function of anion basicity. Whereas the enhanced reactivity of monohydrated and dihydrated ROO(-) (R = H, Me) could be observed if compared them with the specific normal nucleophiles, RO(-) (R = H, Me). This phenomena can not be seen in the comparisons of XO(-)(H2O)(n = 1,2) (X = F, Cl, Br) with ClC2H4O(-)(H2O)(n = 1,2), a normal nucleophile with similar gas basicity to XO(-)(H2O)(n = 1,2). These results have been carefully analyzed by natural bond orbital theory and activation strain model. Meanwhile, the relationships between activation barriers with reaction energies and the ionization energies of α-nucleophile are also discussed.

A dual fusion recognition model for sleep posture based on air mattress pressure detection.

In order to solve the difficult portability problem of traditional non-invasive sleeping posture recognition algorithms arising from the production cost and computational cost, this paper proposes a sleeping posture recognition model focusing on human body structural feature extraction and integration of feature space and algorithms based on a specific air-spring mattress structure, called SPR-DE (SPR-DE is the Sleep Posture Recognition-Data Ensemble acronym form). The model combines SMR (SMR stands for Principle of Spearman Maximal Relevance) with horizontal and vertical division based on the barometric pressure signals in the human body's backbone region to reconstruct the raw pressure data into strongly correlated non-image features of the sleep postures in different parts and directions and construct the feature set. Finally, the recognit-ion of the two sleep postures is accomplished using the AdaBoost-SVM integrated classifier. SPR-DE is compared with the base and integrated classifiers to verify its performance. The experimental results show that the amount of significant features helps the algorithm to classify different sleeping patterns more accurately, and the f1 score of the SPR-DE model determined by the comparison experiments is 0.998, and the accuracy can reach 99.9%. Compared with other models, the accuracy is improved by 2.9% ~ 7.7%, and the f1-score is improved by 0.029 ~ 0.076. Therefore, it is concluded that the SMR feature extraction strategy in the SPR-DE model and the AdaBoost-SVM can achieve high accuracy and strong robustness in the task of sleep posture recognition in a small area, low-density air-pressure mattress, taking into account the comfort of the mattress structural design and the sleep posture recognition, integrated with the mattress adaptive adjustment system.

Mediating role of social support in dysphoria, despondency, and quality of life in patients undergoing maintenance hemodialysis.

BACKGROUND: Dysphoria and despondency are prevalent psychological issues in patients undergoing Maintenance Hemodialysis (MHD) that significantly affect their quality of life (QOL). High levels of social support can significantly improve the physical and mental well-being of patients undergoing MHD. Currently, there is limited research on how social support mediates the relationship between dysphoria, despondency, and overall QOL in patients undergoing MHD. It is imperative to investigate this mediating effect to mitigate dysphoria and despondency in patients undergoing MHD, ultimately enhancing their overall QOL. AIM: To investigate the mediating role of social support in relationships between dysphoria, despondency, and QOL among patients undergoing MHD. METHODS: Participants comprised 289 patients undergoing MHD, who were selected using a random sampling approach. The Social Support Rating Scale, Self-Rating Anxiety Scale, Self-Rating Depression Scale, and QOL Scale were administered. Correlation analysis was performed to examine the associations between social support, dysphoria, despondency, and QOL in patients undergoing MHD. To assess the mediating impact of social support on dysphoria, despondency, and QOL in patients undergoing MHD, a bootstrap method was applied. RESULTS: Significant correlations among social support, dysphoria, despondency, and quality in patients undergoing MHD were observed (all P < 0.01). Dysphoria and despondency negatively correlated with social support and QOL (P < 0.01). Dysphoria and despondency had negative predictive impacts on the QOL of patients undergoing MHD (P < 0.05). The direct effect of dysphoria on QOL was statistically significant (P < 0.05). Social support mediated the relationship between dysphoria and QOL, and this mediating effect was significant (P < 0.05). Similarly, the direct effect of despondency on QOL was significant (P < 0.05). Moreover, social support played a mediating role between despondency and QOL, with a significant mediating effect (P < 0.05). CONCLUSION: These findings suggest that social support plays a significant mediating role in the relationship between dysphoria, despondency, and QOL in patients undergoing MHD.

Molecule Anchoring Strategy Promotes Vertically Homogeneous Crystallization and Aligned Interfaces for Efficient Pb-Sn Perovskite Solar Cells and Tandem Device.

Narrow-bandgap (NBG) Pb-Sn perovskites are ideal candidates as rear subcell in all-perovskite tandem solar cells. Because Pb-Sn perovskites contain multiple components, the rational regulation of vertical structure and both interfaces of the film is primarily crucial to achieve high-performing NBG perovskite solar cells (PSCs). Herein, a molecule anchoring strategy is developed to in situ construct Cs0.1MA0.3FA0.6Pb0.5Sn0.5I3 perovskite film with vertically aligned crystals and optimized interfaces. Specifically, l-alanine methyl ester is developed as an anchoring additive to induce the vertical crystal growth, while PEA2PbI3SCN film is introduced to promote the homogeneous crystallization at the buried interface via SCN- anchoring with cations. Further ethylenediamine dihalides (EDA(I/Cl)2) post-treatment leads to the gradient energy level alignment on the film surface. Pb-Sn PSCs based on such film show efficient charge transport and extraction, producing a champion power conversion efficiency (PCE) of 22.3% with an impressive fill factor of 82.14%. Notably, combining with semitransparent 1.78 eV wide-bandgap PSCs, the four-terminal all-perovskite tandem device achieves a PCE of 27.1%. This work opens up a new pathway to boost the performance of Pb-Sn PSCs and their tandem devices.

Neutrophil-Driven M2-Like Macrophages Are Critical for Skin Fibrosis in a Systemic Sclerosis Model.

Systemic sclerosis (SSc) is a challenging autoimmune disease characterized by progressive fibrosis affecting the skin and internal organs. Despite the known infiltration of macrophages and neutrophils, their precise contributions to SSc pathogenesis remain elusive. In this study, we elucidated that CD206hiMHCIIlo M2-like macrophages constitute the predominant pathogenic immune cell population in the fibrotic skin of a bleomycin-induced SSc mouse model. These cells emerged as pivotal contributors to the profibrotic response by orchestrating the production of TGF-ß1 through a MerTK signaling-dependent manner. Notably, we observed that neutrophil infiltration was a prerequisite for accumulation of M2-like macrophages. Strategies such as neutrophil depletion or inhibition of CXCR1/2 were proven effective in reducing M2-like macrophages, subsequently mitigating SSc progression. Detailed investigations revealed that in fibrotic skin, neutrophil-released neutrophil extracellular traps were responsible for the differentiation of M2-like macrophages. Our findings illuminate the significant involvement of the neutrophil-macrophage-fibrosis axis in SSc pathogenesis, offering critical information for the development of potential therapeutic strategies.

Machine Learning Assisted Simulations of Electrochemical Interfaces: Recent Progress and Challenges.

The electrochemical interface, where the adsorption of reactants and electrocatalytic reactions take place, has long been a focus of attention. Some of the important processes on it tend to possess relatively slow kinetic characteristics, which are usually beyond the scope of ab initio molecular dynamics. The newly emerging technique, machine learning methods, provides an alternative approach to achieve thousands of atoms and nanosecond time scale while ensuring precision and efficiency. In this Perspective, we summarize in detail the recent progress and achievements made by the introduction of machine learning to simulate electrochemical interfaces, and focus on the limitations of current machine learning models, such as accurate descriptions of long-range electrostatic interactions and the kinetics of the electrochemical reactions occurring at the interface. Finally, we further point out the future directions for machine learning to expand in the field of electrochemical interfaces.

Recent advances of bioresponsive polymeric nanomedicine for cancer therapy.

A bioresponsive polymeric nanocarrier for drug delivery is able to alter its physical and physicochemical properties in response to a variety of biological signals and pathological changes, and can exert its therapeutic efficacy within a confined space. These nanosystems can optimize the biodistribution and subcellular location of therapeutics by exploiting the differences in biochemical properties between tumors and normal tissues. Moreover, bioresponsive polymer-based nanosystems could be rationally designed as precision therapeutic platforms by optimizing the combination of responsive elements and therapeutic components according to the patient-specific disease type and stage. In this review, recent advances in smart bioresponsive polymeric nanosystems for cancer chemotherapy and immunotherapy will be summarized. We mainly discuss three categories, including acidity-sensitive, redox-responsive, and enzyme-triggered polymeric nanosystems. The important issues regarding clinical translation such as reproducibility, manufacture, and probable toxicity, are also commented.

Toward Low-Symmetry Systems: An Adaptive Differential Evolution Algorithm for Global Structure Searching.

The reduction in the symmetry of nanomaterials can produce unexpected properties, while the determination of atomic structures is a sizable challenge in related fields, including low-dimensional materials, surface science, defects, etc. Herein, we develop an adaptive algorithm based on the differential evolution algorithm, which provides benefits for structure searching on low-symmetry systems. The dynamic strategy pool and the island concept are proposed to accelerate the efficiency in the full search space. With several test examples, the designed program not only locates reported structures but also affords new stable configurations that were not located by previous structure search algorithms. Moreover, we provide frameworks and interfaces for stable structure searching on complex systems like grain boundaries, supported clusters, surfaces, and edges. The success in repeatable structure searching with high efficiency demonstrates the reliability and practicability of our algorithm and ensures its potential applications as an advanced technology in many newly arising fields.

N, P, O co-doped carbon filling into carbon nitride microtubes to promote photocatalytic hydrogen production.

Carbon nitride (CN) as the photocatalytic hydrogen production catalyst has attracted great attentions but suffering from a poor performance due to the unsatisfied energy band gap and the low separation efficiency of photogenerated carriers. Herein, we create a simple method to construct a novel CN-based photocatalyst, i.e., the N, P, O co-doped carbon filled CN microtube, which presents a narrow band gap, a high separation efficiency of photogenerated carriers, and a good stability. In this novel structure, the tubular morphology of CN ensures a narrow band gap, and the N, P, O co-doped carbon facilitates the transfer of photogenerated electrons. Coupling these two further reduces the energy band gap and improves the separation efficiency. For the photocatalytic hydrogen evolution under the visible light, the optimal sample presents an ultrahigh hydrogen evolution rate of 1149.71 µmol g-1 h-1 ranking at the top level, which is 112.60 times that of traditional bulk CN. In addition, it also has a high reusability and good stability after four cycle experiments. This study has provided a new viewpoint to design or develop the high-efficient photocatalysts for hydrogen production.

Enhanced photocatalytic CO2-reduction activity to form CO and CH4 on S-scheme heterostructured ZnFe2O4/Bi2MoO6 photocatalyst.

A novel ZnFe2O4/Bi2MoO6 heterojunction photocatalyst was synthesized by a facile solvothermal route. The incorporation of a narrow bandgap ZnFe2O4 photocatalyst can efficiently improve the range of light response and light absorption capacity of the Bi2MoO6 via the formation of a hybrid structure at the interface. The formed hybrid interface facilitates the separation efficiency of photo-generated carriers at ZnFe2O4/Bi2MoO6 heterojunction significantly. The experimental results confirm that ZnFe2O4/Bi2MoO6-20% heterojunction showed the highest photocatalytic efficiency for CO2 reduction. Specifically, the total product yield of 47.1 µmol g-1 under 5 h simulated sunlight irradiation is measured in the counterparts of pure ZnFe2O4 (14.79 µmol g-1) and pure Bi2MoO6 (19.01 µmol g-1). Indeed, the formation of ZnFe2O4/Bi2MoO6 heterojunction improved the photocatalytic efficiency for CO2 reduction.

The secretion profile of mesenchymal stem cells and potential applications in treating human diseases.

Mesenchymal stromal/stem cells (MSCs) possess multi-lineage differentiation and self-renewal potentials. MSCs-based therapies have been widely utilized for the treatment of diverse inflammatory diseases, due to the potent immunoregulatory functions of MSCs. An increasing body of evidence indicates that MSCs exert their therapeutic effects largely through their paracrine actions. Growth factors, cytokines, chemokines, extracellular matrix components, and metabolic products were all found to be functional molecules of MSCs in various therapeutic paradigms. These secretory factors contribute to immune modulation, tissue remodeling, and cellular homeostasis during regeneration. In this review, we summarize and discuss recent advances in our understanding of the secretory behavior of MSCs and the intracellular communication that accounts for their potential in treating human diseases.

Mesenchymal stem cells alleviate systemic sclerosis by inhibiting the recruitment of pathogenic macrophages.

Systemic sclerosis (SSc) is a recalcitrant autoimmune disease for which there is no cure. Mesenchymal stem cell (MSC)-based treatment has emerged as a promising therapeutic option for several autoimmune diseases. Previously, we found that the immunoregulatory potential of MSCs can be greatly enhanced by IFN-γ and TNF-α. Here, we found that IFN-γ- and TNF-α-pretreated MSCs significantly alleviated skin fibrosis in a bleomycin (BLM)-induced SSc model. Macrophages were found to be the predominant profibrotic immune cell population in the pathogenesis of SSc. The accumulation of macrophages was significantly decreased by MSC treatment. Importantly, MSCs primarily reduced the population of maturing macrophages with high CCR2 expression by inhibiting the generation of CCL2 from fibroblasts and macrophages. This finding may help to improve MSC-based clinical treatments for SSc patients.