Enhanced Charge Transfer in Quasi-2D Perovskite by Formamidinium Cation Gradient Incorporation for Efficient and Stable Solar Cells.

Quasi-2D perovskites have attracted much attention in perovskite photovoltaics due to their excellent stability. However, their photoelectric conversion efficiency (PCE) still lags 3D counterparts, particularly with high short-circuit current (JSC) loss. The quantum confinement effect is pointed out to be the sole reason, which introduces widened bandgap and poor exciton dissociation, and undermines the light capture and charge transport. Here, the gradient incorporation of formamidinium (FA) cations into quasi-2D perovskite is proposed to address this issue. It is observed that FA prefers to incorporate into the larger n value phases near the film surface compared to the smaller n value phases in the bulk, resulting in a narrow bandgap and gradient structure within the film. Through charge dynamic analysis using in situ light-dark Kelvin probe force microscopy and transient absorption spectroscopy, it is demonstrated that incorporating 10% FA significantly facilitates efficient charge transfer between low n-value phases in the bulk and high n-value nearby film surface, leading to reduced charge accumulation. Ultimately, the device based on (AA)2(MA0.9FA0.1)4Pb5I16, where AA represents n-amylamine renowned for its exceptional environmental stability as a bulky organic ligand, achieves an impressive power conversion efficiency (PCE) of 18.58% and demonstrates enhanced illumination and thermal stability.

3D Conjugated Hole Transporting Materials for Efficient and Stable Perovskite Solar Cells and Modules.

The orthogonal structure of the widely used hole transporting material (HTM) 2,2',7,7'-tetrakis(N, N-di-p-methoxyphenylamino)-9,9'-spirobifluorene (Spiro-OMeTAD) imparts isotropic conductivity and excellent film-forming capability. However, inherently weak intra- and inter-molecular π-π interactions result in low intrinsic hole mobility. Herein, a novel HTM, termed FTPE-ST, with a twist conjugated dibenzo(g,p)chrysene core and coplanar 3,4-ethylenedioxythiophene (EDOT) as extended donor units, is designed to enhance π-π interactions, without compromising on solubility. The three-dimensional (3D) configuration provides the material multi-direction charge transport as well as excellent solubility even in 2-methylanisole, and its large conjugated backbone endows the HTM with a high hole mobility. Moreover, the sulfur donors in EDOT units coordinate with lead ions on the perovskite surface, leading to stronger interfacial interactions and the suppression of defects at the perovskite/HTM interface. As a result, perovskite solar cells (PSCs) employing FTPE-ST achieve a champion power conversion efficiency (PCE) of 25.21% with excellent long-time stability, one of the highest PCEs for non-spiro HTMs in n-i-p PSCs. In addition, the excellent film-forming capacity of the HTM enables the fabrication of FTPE-ST-based large-scale PSCs (1.0 cm2) and modules (29.0 cm2), which achieve PCEs of 24.21% (certificated 24.17%) and 21.27%, respectively.

A Multifunctional Dye Molecule as the Interfacial Layer for Perovskite Solar Cells.

In perovskite solar cells (PSCs), defects in the interface and mismatched energy levels can damage the device performance. Improving the interface quality is an effective way to achieve efficient and stable PSCs. In this work, a multifunctional dye molecule, named ThPCyAc, was designed and synthesized to be introduced in the perovskite/HTM interface. On one hand, various functional groups on the acceptor unit can act as Lewis base to reduce defect density and suppress nonradiative combinations. On the other hand, the stepwise energy-level alignment caused by ThPCyAc decreases the accumulation of interface carriers for facilitating charge extraction and transmission. Therefore, based on the ThPCyAc molecule, the devices exhibit elevated open-circuit voltage and fill factor, resulting in the best power conversion efficiency (PCE) of 23.16%, outperforming the control sample lacking the interface layer (PCE = 21.49%). Excitingly, when attempting to apply it as a self-assembled layer in inverted devices, ThPCyAc still exhibits attractive behavior. It is worth noting that these results indicate that dye molecules have great potential in developing multifunctional interface materials to obtain higher-performance PSCs.

Dopant-Free Pyrene-Based Hole Transporting Material Enables Efficient and Stable Perovskite Solar Cells.

Dopant-free hole transporting materials (HTMs) is significant to the stability of perovskite solar cells (PSCs). Here, we developed a novel star-shape arylamine HTM, termed Py-DB, with a pyrene core and carbon-carbon double bonds as the bridge units. Compared to the reference HTM (termed Py-C), the extension of the planar conjugation backbone endows Py-DB with typical intermolecular π-π stacking interactions and excellent solubility, resulting in improved hole mobility and film morphology. In addition, the lower HOMO energy level of the Py-DB HTM provides efficient hole extraction with reduced energy loss at the perovskite/HTM interface. Consequently, an impressive power conversion efficiency (PCE) of 24.33 % was achieved for dopant-free Py-DB-based PSCs, which is the highest PCE for dopant-free small molecular HTMs in n-i-p configured PSCs. The dopant-free Py-DB-based device also exhibits improved long-term stability, retaining over 90 % of its initial efficiency after 1000 h exposure to 25 % humidity at 60 °C. These findings provide valuable insights and approaches for the further development of dopant-free HTMs for efficient and reliable PSCs.

A "turn-on" fluorescence resonance energy transfer aptasensor based on carbon dots and gold nanoparticles for 17ß-estradiol detection in sea salt.

17ß-estradiol is abused in the food industry. Excess 17ß-estradiol can disturb the endocrine system or cause many diseases including obesity, diabetes, cardiac-cerebral vascular disease, and cancers in the human body. A "turn-on" fluorescence resonance energy transfer (FRET) aptasensor based on carbon dots (CDs) and gold nanoparticles (AuNPs) was developed for the detection of 17ß-estradiol. A thiol-modified oligonucleotide was conjugated to AuNPs and amino modified oligonucleotide was linked to CDs. The 17ß-estradiol aptamer was hybridized with the two oligonucleotides, shortening the distance between CDs and AuNPs. With 360 nm UV light excitation, FRET occurred between CDs and AuNPs. The system was "turn-off". When 17ß-estradiol was detected, the aptamer specifically bound to 17ß-estradiol, and the FRET system was destroyed, leading to the "turn-on" phenomenon. The fluorescence intensity recovery was detected in the concentration range of 400 pM to 5.5 µM. The limit of detection (LOD) was 245 pM. The FRET aptasensor demonstrated good selectivity for 17ß-estradiol detection. Reasonable spiked recoveries were obtained in sea salt samples. It showed the potential for estrogen detection in food safety and environmental applications.

Extending the π-Conjugated System in Spiro-Type Hole Transport Material Enhances the Efficiency and Stability of Perovskite Solar Modules.

Hole transport materials (HTMs) are a key component of perovskite solar cells (PSCs). The small molecular 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl)-amine-9,9'-spirobifluorene (spiro-OMeTAD, termed "Spiro") is the most successful HTM used in PSCs, but its versatility is imperfect. To improve its performance, we developed a novel spiro-type HTM (termed "DP") by substituting four anisole units on Spiro with 4-methoxybiphenyl moieties. By extending the π-conjugation of Spiro in this way, the HOMO level of the HTM matches well with the perovskite valence band, enhancing hole mobility and increasing the glass transition temperature. DP-based PSC achieves high power conversion efficiencies (PCEs) of 25.24 % for small-area (0.06 cm2 ) devices and 21.86 % for modules (designated area of 27.56 cm2 ), along with the certified efficiency of 21.78 % on a designated area of 27.86 cm2 . The encapsulated DP-based devices maintain 95.1 % of the initial performance under ISOS-L-1 conditions after 2560 hours and 87 % at the ISOS-L-3 conditions over 600 hours.

From collapse to the health of the aquatic ecosystem in Dasha River (2006-2021): a case study of Shenzhen city in the Guangdong-Hong Kong-Macao Greater Bay Area, China.

Compared with the aquatic ecosystem destruction caused by rapid urban development, substantial ecological restoration usually requires long periods and is a challenging process. Although river ecological restoration has been successful in different regions, the relationship between biodiversity, water quality, and effective measures applicable to developing countries remains poorly understood. This study was conducted in the Dasha River in Shenzhen city, one of the fastest-growing cities in China. The rehabilitation measures were sorted out in four phases to study the impact on water quality and biodiversity. In response, three campaigns were carried out to take phytoplankton, zooplankton, and benthos samples within the last three engineering stages, in 2007, 2012, and 2021. Synchronized investigations of water quality were conducted monthly from 2006 to 2021. Our analysis showed that the biodiversity of benthos has improved in recent years, which marks a turnaround for the aquatic ecological environment. According to the Hilsenhoff family biotic index (FBI), the water quality level in the 2021 campaign was promoted to "Good" in the downstream and "Fair" in the upper and middle streams. By analyzing Pearson's correlations between response ratios of water quality parameters and the Shannon-Wiener index of phytoplankton, zooplankton, and benthos, we concluded that biodiversity is significantly related to water quality. Specifically, the biodiversity of zooplankton is associated with ammonia nitrogen (NH3-N) (R2 = - 0.77, P < 0.05), and benthos diversity is strongly negatively correlated with NH3-N, total nitrogen, chemical oxygen demand, and biochemical oxygen demand (R2 ≥ -0.82, P < 0.01). Despite the temporary negative impact of along-river interception on aquatic organisms in the campaign of 2012, the measures quickly and effectively improved water quality, which is the foundation for biodiversity improvement in 2021. This study provides insights into relationships among biodiversity, water quality, and regulation projects and can offer a reference for selecting aquatic ecosystem restoration measures in developing areas.

Interface modified BTO@PS-co-mah/PS composite dielectrics with enhanced breakdown strength and ultralow dielectric loss.

Dielectrics of the polymer-matrix composite are considered to present combined advantages from both the polymer matrix and inorganic fillers. However, the breakdown strength, as well as energy density, is not effectively enhanced due to the poor compatibility between the organic and inorganic components. Herein, polymer composites derived from polystyrene (PS) and barium titanate (BTO) are proposed and beneficial interface modification by poly(styrene-co-maleic anhydride) (PS-co-mah) is conducted to improve compatibility between the inorganic filler and polymer matrix. The results show that the BTO@PS-co-mah/PS composites, in which the interfacial layer of PS-co-mah would undergo chemical reactions with the aminated BTO and blend PS matrix with excellent physical compatibility, exhibit enhanced breakdown strength and declined dielectric loss compared with both pure PS and BTO/PS without interfacial modulation. Particularly, the BTO@PS-co-mah/PS composite with 5 wt% filler content indicates optimized performance with an E b of 507 MV m-1 and tan δ of 0.085%. It is deduced that the deep energy traps introduced by the PS-co-mah layer would weaken the local electric field and suppress the space charge transporting so as to optimize the performance of composites. Consequently, the interfacial-modified BTO@PS-co-mah/PS would present great potential for applications, such as film capacitors.

Preoperative anxiety as an independent predictor of postoperative delirium in older patients undergoing elective surgery for lumbar disc herniation.

BACKGROUND: Anxiety is common in older patients suffering from lumbar disc herniation. Postoperative delirium is related to poor prognosis. But the relationship between preoperative anxiety and postoperative delirium among older patients undergoing elective surgery for lumbar disc herniation is not clear. AIMS: The study aimed to investigate if preoperative anxiety is an independent risk factor of postoperative delirium among older patients undergoing elective surgery for lumbar disc herniation. METHODS: The medical records of 1290 patients undergoing elective surgery for lumbar disc herniation at a single institution from 2016 through 2021 were reviewed. Of 863 eligible patients, 225 (26.1%) patients had been diagnosed with anxiety by a board-certified psychiatrist and constituted the Anxiety group; the remaining 638 patients constituted the no-anxiety group. The demographics, baseline, operative variable and postoperative complications were collected and compared between the two groups. The primary outcome of this study was the incidence of delirium, according to the Diagnostic and Statistical Manual of Mental Disorders-Fifth Edition, during a hospital stay after surgery for lumbar disc herniation. The relationship between anxiety and postoperative delirium was determined through multivariate logistic regression analysis. RESULTS: The demographics and comorbidity were similar between the two groups, except for age, sex, alcohol use and cerebrovascular disease. The operative variables were different between the two groups. The incidence of postoperative complications other than postoperative delirium was also similar between the two groups. In total, 86 patients (9.97%) had an episode of postoperative delirium, with anxiety group patients experiencing approximately a twofold higher rate (15.6% vs 7.99%). In a multivariate logistic regression analysis, anxiety was an independent predictor of postoperative delirium in older patients undergoing elective surgery for lumbar disc herniation (OR 2.228, 95% CI 1.494-3.416, p = 0.009). CONCLUSION: This study suggests that anxiety is an independent risk factor of postoperative delirium among older patients undergoing elective surgery for lumbar disc herniation. Preoperative anxiety assessment can help to identify older patients at high risk of postoperative delirium and facilitate perioperative management of older patients undergoing elective surgery for lumbar disc herniation.

Significantly Improved Dielectric Performance of All-Organic Parylene/Polyimide/Parylene Composite Films with Sandwich Structure.

The development of novel polymer dielectrics with enhanced dielectric performance is a great challenge for application of film capacitors in modern electronics and electrical systems. Herein, an innovative approach of chemical vapor deposition polymerization technology is proposed to prepare the all-organic sandwich structured parylene/polyimide/parylene (Py/PI/Py) composite films by employing poly(chloro-para-xylylene) (parylene C) as the outer layers and polyimide (PI) as the inner layer. The Py/PI/Py composites exhibit superior thermal resistance and outstanding mechanical properties. Moreover, thanks to the interfacial effect which contributes to reinforcing the dielectric response and the thickness effect which facilitates improving the breakdown strength, the dielectric performance of Py/PI/Py composites has been enhanced significantly. Accordingly, dielectric constant of 4.52-5.09, dissipation factor of 0.21-1.01%, and breakdown strength of 307-460 MV m-1 are achieved. Besides, notable energy storage performance is also obtained in Py/PI/Py composite dielectrics. Consequently, this novel application of chemical vapor deposition polymerization method in preparing all-organic multilayered polymer composite films with sandwich structure shows promising potential in film capacitor applications in harsh conditions.

Entrepreneurial mindfulness and organizational resilience of Chinese SMEs during the COVID-19 pandemic: The role of entrepreneurial resilience.

Organizational resilience is vital to the survival and thriving of enterprises, especially during the COVID-19 pandemic. Although there has been an increasing interest in organizational resilience, the effects from the entrepreneur perspective receive scant attention. Based on upper echelons theory (UET) and personality psychology, we propose a model in which entrepreneurial mindfulness and entrepreneurial resilience could influence organizational resilience of SMEs. We empirically analyzed a sample of 180 entrepreneurs managing small- and medium-sized enterprises (SMEs) in China during the COVID-19 pandemic, using SmartPLS software. The research findings indicated that entrepreneurial mindfulness is positively associated with organizational resilience and such relationship is partially mediated by entrepreneurial resilience. These findings convey important theoretical implications in this field of research as well as practical implications for SMEs in China or other countries with similar nature.

The trade impact of the COVID-19 pandemic.

Using a gravity-like approach, we study how COVID-19 deaths and lockdown policies affected countries' imports from China during 2020. We find that a country's own COVID-19 deaths and lockdowns significantly reduced its imports from China, suggesting that the negative demand effects prevailed over the negative supply effects of the pandemic. On the contrary, COVID-19 deaths in the main trading partners of a country (excluding China) induce more imports from China, partially offsetting countries' own effects. The net effect of moving from the pre-pandemic situation to another where the main variables are evaluated at their 2020 mean is, on average, a reduction of nearly 10% in imports from China. There is also significant heterogeneity. For example, the negative own effects of the pandemic vanish when we restrict the sample to medical goods and are significantly mitigated for products with a high 'work-from-home' share or a high contract intensity for products exported under processing trade and for capital goods. We also find that deaths and lockdowns in previous months tend to increase current imports from China, partially offsetting the contemporaneous trade loss, suggesting that trade is not simply 'destroyed,' but partially 'postponed'.

A N-Ethylcarbazole-Terminated Spiro-Type Hole-Transporting Material for Efficient and Stable Perovskite Solar Cells.

The development of stable and efficient hole-transporting materials (HTMs) is critical for the commercialization of perovskite solar cells (PSCs). Herein, a novel spiro-type HTM was designed and synthesized where N-ethylcarbazole-terminated groups fully substituted the methoxy group of spiro-OMeTAD, named spiro-carbazole. The developed molecule exhibited a lower highest occupied molecular orbital level, higher hole mobility, and extremely high glass transition temperature (Tg =196 °C) compared with spiro-OMeTAD. PSCs with the developed molecule exhibited a champion power conversion efficiency (PCE) of 22.01 %, which surpassed traditional spiro-OMeTAD (21.12 %). Importantly, the spiro-carbazole-based device had dramatically better thermal, humid, and long-term stability than spiro-OMeTAD.

Forsythoside B attenuates neuro-inflammation and neuronal apoptosis by inhibition of NF-κB and p38-MAPK signaling pathways through activating Nrf2 post spinal cord injury.

BACKGROUND: Spinal cord injury (SCI) is a ruinous neurological pathology that results in locomotor and sensory impairment. Neuro-inflammation and secondary neuronal apoptosis contribute to SCI, with anti-inflammatory therapies the focus of many SCI studies. Forsythoside B (FTS•B), a phenylethanoid glycoside extracted from the leaves of Lamiophlomis rotata Kudo, has been shown previously to have anti-inflammatory properties. Nevertheless, the therapeutic effect of FTS•B on neuro-inflammation after SCI is unknown. METHODS: Neuro-inflammation was assessed by western blotting (WB), immunofluorescence (IF) staining, and enzyme-linked immunosorbent assay (ELISA) both in vitro and in vivo. Secondary neuronal apoptosis was simulated in a microglia-neuron co-culture model with the degree of apoptosis measured by WB, IF, and TUNEL staining. In vivo, FTS•B (10 mg/kg, 40 mg/kg) were intraperitoneally injected into SCI mice. Morphological changes following SCI were evaluated by Nissl, Hematoxylin-eosin, and Luxol Fast Blue staining. Basso Mouse Scale scores were used to evaluate locomotor function recovery. RESULTS: FTS•B markedly decreased the levels of iNOS, COX-2 and signature mediators of inflammation. Phosphorylated p38 and nuclear factor-kappa B (NF-κB) were markedly decreased by FTS•B. Additionally, FTS•B-induced inhibition of NF-κB and p38-MAPK signaling pathways was reversed by Nrf2 downregulation. Administration of FTS•B also significantly reduced apoptosis-related protein levels indicating that FTS•B ameliorated secondary neuronal apoptosis. FTS•B administration inhibited glial scar formation, decreased neuronal death, tissue deficiency, alleviated demyelination, and promoted locomotor recovery. CONCLUSION: FTS•B effectively attenuates neuro-inflammation and secondary neuronal apoptosis by inhibition of NF-κB and p38-MAPK signaling pathways through activating Nrf2 after SCI. This study demonstrates FTS•B to be a potential therapeutic for SCI.

Population Pharmacokinetics and Dosing Regimen of Lithium in Chinese Patients With Bipolar Disorder.

Background: Lithium is an effective medication approved for the treatment of bipolar disorder (BD). It has a narrow therapeutic index (TI) and requires therapeutic drug monitoring. This study aimed to conduct a population pharmacokinetics (PPK) analysis of lithium and investigate the appropriateness of the dosing regimen according to different patient characteristics. Methods: A total of 476 lithium concentrations from 268 patients with bipolar disorder were analyzed using nonlinear mixed-effects modeling. Monte Carlo simulations were employed to investigate the influence of covariates, such as weight, creatinine clearance, and daily doses of lithium concentrations, and to determine the individualized dosing regimens for patients. Results: Lithium PK was described by a one-compartment model with first-order absorption and elimination processes. The typical estimated apparent clearance was 0.909 L/h-1 with 16.4% between-subject variability in the 62 kg patients with 116 ml/min creatinine clearance and 600 mg daily doses. To achieve a target trough concentration (0.4-0.8 mmol/L) in the maintenance phase, the regimen of 500 mg than 750 mg daily dose was recommended for patients with renal insufficiency and weighing 100 kg. Conclusion: A PPK model for lithium was developed to determine the influence of patient characteristics on lithium pharmacokinetics. Weight, creatinine clearance, and total daily dose of lithium can affect the drug's clearance. These results demonstrate the nonlinear renal excretion of lithium; hence, dosage adjustments are recommended for patients with renal insufficiency.

Atomistic simulations of mechanical response of a heterogeneous fcc/bcc nanolayered composite.

Molecular dynamics simulations are performed to study the mechanical properties and deformation mechanisms of a heterogeneous face-centered cubic/ body-centered cubic Cu/Ta nanolayered composite under uniaxial tension and compression. The results show that the stress-strain curves exhibit two main yield points in tension while only one yield point during compression, and the deformation primarily experiences three stages. The first stage is linearly elastic at small strains, followed by the nucleation and propagation of dislocations and stacking faults in the Cu layers, and eventually the Ta layers yield to plastic deformation. The yield of the specimen is mainly determined by the dislocation evolution in the hard phase (i.e. Ta layers), which leads to a sharp drop in the stress-strain curve. We show that the heterogeneous nanolayered composite exhibits a good deformation compatibility during compression but an obvious deformation incompatibility between Cu and Ta layers in tension. The temperature effect is also systematically investigated. It is revealed that the yield of the specimen at higher temperature depends only on the dislocation evolution in the thick Ta layers, and the yield strengths in tension and compression both decrease with the increasing temperature. In particular, our computations show that high temperature can significantly suppress the dislocation activities in the Cu layers during deformation, which results in a lower dislocation density of the Cu layers compared with that of the Ta layers and thus causing an incompatible fashion among the constituent layers.

Insight into the Potential of Meehania fargesii var. Radicans against Hp-Induced Gastric Carcinoma Based on Phytochemical and Molecular Docking Studies.

We used UV-guided method to isolate and identify 12 secondary metabolites from Meehania fargesii var. Radicans for the first time, including eight triterpenoids (1-8), two phenylpropanoid derivatives (9-10) and two flavone glycosides (11-12). Their structures were identified by NMR spectroscopic methods, as well as literature comparison. The identified compounds and positive drugs (amoxicillin, omeprazole and clarithromycin) were further analyzed for their in silico docking interactions with HtrA using igemdock. Docking studies revealed the high binding affinity of phytochemicals at significant sites with HtrA, compounds 11 and 12 exhibiting stronger binding ability than standard drug, 1 and 3-10 demonstrating comparable docking capacity to standard drugs. The chemotaxonomic relationships were carried out to exploring the possibilities of other medicinal plants against Hp-induced gastric carcinoma. The results demonstrated there are closely chemotaxonomic similarity among several genera of the Lamiaceae family as well as among Lamiaceae, Actinidiaceae and Rosaceae families, indicating a similar chemical compositions and anti-Hp-induces gastric carcinoma activity among them.

Tetraphenylethylene-Arylamine Derivatives as Hole Transporting Materials for Perovskite Solar Cells.

A series of hole transporting materials (HTMs) with fused tetraphenylethylene cores (9,9'-bifluorenylidene and dibenzo[g,p]chrysene) as well as different substitution positions of arylamine side arms has been designed and synthesized. A reference HTM with a non-fused tetraphenylethylene core is also prepared for a comparative study. It is noted that fused tetraphenylethylene molecules show a bathochromic spectral shift, electronegative character, and lower reorganization energies than the non-fused ones. Furthermore, the molecules with side arms located on the meta-position on the tetraphenylethylene core in terms of a double bond exhibit a deeper highest occupied molecular orbital level than those of the para-position-based ones whether tetraphenylethylene is fused or not. Moreover, the reorganization energies of fused meta-position-based HTMs are lower than those of para-position-based HTMs. Fused tetraphenylethylene HTMs own a better hole-extraction capability than the non-fused ones. When used in perovskite solar cells, all devices with fused tetraphenylethylene HTMs display better performance than those of the non-fused ones. The HTMs based on dibenzo[g,p]chrysene exhibit better performance than those of bifluorenylidene. Moreover, the devices with HTMs with side arms located on the meta-position on the tetraphenylethylene core display higher power conversion efficiency than those of the para-position-based ones. The results give some new insight and reference to develop ideal HTMs for perovskite solar cells.

Introducing ammonium salt into hole transporting materials for perovskite solar cells.

The developed ammonium salt-containing hole transporting material could passivate perovskite defects and transport holes, and exhibits better performance compared with the non-ammonium salt counterpart.