Vertically Concentrated Quantum Wells Enabling Highly Efficient Deep-Blue Perovskite Light-Emitting Diodes.

Deep-blue perovskite light-emitting diodes (PeLEDs) based on quasi-two-dimensional (quasi-2D) systems exist heightened sensitivity to the domain distribution. The top-down crystallization mode will lead to a vertical gradient distribution of quantum well (QW) structure, which is unfavorable for deep-blue emission. Herein, a thermal gradient annealing treatment is proposed to address the polydispersity issue of vertical QWs in quasi-2D perovskites. The formation of large-n domains at the upper interface of the perovskite film can be effectively inhibited by introducing a low-temperature source in the annealing process. Combined with the utilization of NaBr to inhibit the undesirable n=1 domain, a vertically concentrated QW structure is ultimately attained. As a result, the fabricated device delivers a narrow and stable deep-blue emission at 458 nm with an impressive external quantum efficiency (EQE) of 5.82 %. Green and sky-blue PeLEDs with remarkable EQE of 21.83 % and 17.51 % are also successfully achieved, respectively, by using the same strategy. The findings provide a universal strategy across the entire quasi-2D perovskites, paving the way for future practical application of PeLEDs.

Adult-specific collagen COL-19 is dispensable for contact-mediated mate recognition in Caenorhabditis elegans.

Mate recognition in C. elegans involves the integration of multiple sensory cues to facilitate the identification of suitable mates for reproductive behaviors. The cuticle, serving as the protective outer layer enveloping the entire body, has been implicated in eliciting contact responses essential for contact-mediated mate recognition in males. However, the specific constituents of cuticular cues have yet to be identified. In this study, we investigate the potential modulatory role of adult-specific collagen COL-19 in contact-mediated mate recognition. Our study shows that the expression of COL-19 ::GFP is adult-specific and not sexually dimorphic. Knockdown of col-19 via RNAi does not affect mate attractiveness of hermaphrodites in male retention assay, as corroborated by generating two independent col-19 putative null mutants via CRISPR/Cas9. These findings suggest that col-19 does not contribute to contact-mediated mate recognition, thereby advancing our mechanistic understanding of the intricate social interactions between sexes in C. elegans .

In Situ Hydrolysis of Phosphate Enabling Sky-Blue Perovskite Light-Emitting Diode with EQE Approaching 16.32.

The performance of blue perovskite light-emitting diodes (PeLEDs) lags behind the green and red counterparts owing to high trap density and undesirable red shift of the electroluminescence spectrum under operation conditions. Organic molecular additives were employed as passivators in previous reports. However, most commonly have limited functions, making it challenging to effectively address both efficiency and stability issues simultaneously. Herein, we reported an innovatively dynamic in situ hydrolysis strategy to modulate quasi-2D sky-blue perovskites by the multifunctional passivator phenyl dichlorophosphate that not only passivated the defects but also underwent in situ hydrolysis reaction to stabilize the emission. Moreover, hydrolysis products were beneficial for low-dimensional phase manipulation. Eventually, we obtained high-performance sky-blue PeLEDs with a maximum external quantum efficiency (EQE) of 16.32% and an exceptional luminance of 5740 cd m-2. More importantly, the emission peak of devices located at 485 nm remained stable under different biases. Our work signified the significant advancement toward realizing future applications of PeLEDs.

Photochemical Shield Enabling Highly Efficient Perovskite Photovoltaics.

Oxygen is difficult to be physically removed. Oxygen will be excited by light to form free radicals which further attack the lattice of perovskite. The stabilization of α-FAPbI3 against δ-FAPbI3 is the key to optimize perovskite solar cells. Herein, the simple molecule, benzaldehyde (BAH) is adopted. The photochemical shield will be established in perovskite layer. Moreover, heterogeneous nucleation induced by BAH enhances the crystallization of α-FAPbI3 . Consequently, the stability of device is improved significantly. The target device maintains 95% of original power conversion efficiency after 1500 h under air conditions and light-emitting diode light. The power conversion efficiency increases from 23.21% of pristine device to 24.82% of target device.

Electronically Manipulated Molecular Strategy Enabling Highly Efficient Tin Perovskite Photovoltaics.

Buried interface modification can effectively improve the compatibility between interfaces. Given the distinct interface selections in perovskite solar cells (PSCs), the applicability of a singular modification material remains limited. Consequently, in response to this challenge, we devised a tailored molecular strategy based on the electronic effects of specific functional groups. Therefore, we prepared three distinct silane coupling agents, and due to the varying inductive effects of these functional groups, the electronic distribution and molecular dipole moments of the coupling agents are correspondingly altered. Among them, trimethoxy (3,3,3-trifluoropropyl)-silane (F3 -TMOS), which possesses electron-withdrawing groups, generates a molecular dipole moment directed toward the hole transport layer (HTL). This approach changes the work function of the HTL, optimizes the energy level alignment, reduces the open-circuit voltage loss, and facilitates carrier transport. Furthermore, through the buffering effect of the coupling agent, the interface strain and lattice distortion caused by annealing the perovskite are reduced, enhancing the stability of the tin-based perovskite. Encouragingly, tin PSCs treated with F3 -TMOS achieved a champion efficiency of 14.67 %. This strategy provides an expedient avenue for the design of buried interface modification materials, enabling precise molecular adjustments in accordance with distinct interfacial contexts to ameliorate mismatched energetics and enhance carrier dynamics.

Magnetic-biased chiral molecules enabling highly oriented photovoltaic perovskites.

The interaction between sites A, B and X with passivation molecules is restricted when the conventional passivation strategy is applied in perovskite (ABX3) photovoltaics. Fortunately, the revolving A-site presents an opportunity to strengthen this interaction by utilizing an external field. Herein, we propose a novel approach to achieving an ordered magnetic dipole moment, which is regulated by a magnetic field via the coupling effect between the chiral passivation molecule and the A-site (formamidine ion) in perovskites. This strategy can increase the molecular interaction energy by approximately four times and ensure a well-ordered molecular arrangement. The quality of the deposited perovskite film is significantly optimized with inhibited nonradiative recombination. It manages to reduce the open-circuit voltage loss of photovoltaic devices to 360 mV and increase the power conversion efficiency to 25.22%. This finding provides a new insight into the exploration of A-sites in perovskites and offers a novel route to improving the device performance of perovskite photovoltaics.

A cGAL-UAS bipartite expression toolkit for Caenorhabditis elegans sensory neurons.

Animals integrate sensory information from the environment and display various behaviors in response to external stimuli. In Caenorhabditis elegans hermaphrodites, 33 types of sensory neurons are responsible for chemosensation, olfaction, and mechanosensation. However, the functional roles of all sensory neurons have not been systematically studied due to the lack of facile genetic accessibility. A bipartite cGAL-UAS system has been previously developed to study tissue- or cell-specific functions in C. elegans. Here, we report a toolkit of new cGAL drivers that can facilitate the analysis of a vast majority of the 60 sensory neurons in C. elegans hermaphrodites. We generated 37 sensory neuronal cGAL drivers that drive cGAL expression by cell-specific regulatory sequences or intersection of two distinct regulatory regions with overlapping expression (split cGAL). Most cGAL-drivers exhibit expression in single types of cells. We also constructed 28 UAS effectors that allow expression of proteins to perturb or interrogate sensory neurons of choice. This cGAL-UAS sensory neuron toolkit provides a genetic platform to systematically study the functions of C. elegans sensory neurons.

An observational study on salivary conductivity for fluid status assessment and clinical relevance in acute ischemic stroke during intravenous fluid hydration.

The body fluid status in acute stroke is a crucial determinant in early stroke recovery but a real-time method to monitor body fluid status is not available. This study aims to evaluate the relationship between salivary conductivity and body fluid status during the period of intravenous fluid hydration. Between June 2020 to August 2022, patients presenting with clinical signs of stroke at the emergency department were enrolled. Salivary conductivities were measured before and 3 h after intravenous hydration. Patients were considered responsive if their salivary conductivities at 3 h decreased by more than 20% compared to their baseline values. Stroke severity was assessed using the National Institutes of Health Stroke Scale, and early neurological improvement was defined as a decrease of ≥ 2 points within 72 h of admission. Among 108 recruited patients, there were 35 of stroke mimics, 6 of transient ischemic attack and 67 of acute ischemic stroke. Salivary conductivity was significantly decreased after hydration in all patients (9008 versus 8118 µs/cm, p = 0.030). Among patients with acute ischemic stroke, the responsive group, showed a higher rate of early neurological improvement within 3 days compared to the non-responsive group (37% versus 10%, p = 0.009). In a multivariate logistic regression model, a decrease in salivary conductivity of 20% or more was found to be an independent factor associated with early neurological improvement (odds ratio 5.42, 95% confidence interval 1.31-22.5, p = 0.020). Real-time salivary conductivity might be a potential indicator of hydration status of the patient with acute ischemic stroke.

Body stiffness is a mechanical property that facilitates contact-mediated mate recognition in Caenorhabditis elegans.

Physical contact is prevalent in the animal kingdom to recognize suitable mates by decoding information about sex, species, and maturity. Although chemical cues for mate recognition have been extensively studied, the role of mechanical cues remains elusive. Here, we show that C. elegans males recognize conspecific and reproductive mates through short-range cues, and that the attractiveness of potential mates depends on the sex and developmental stages of the hypodermis. We find that a particular group of cuticular collagens is required for mate attractiveness. These collagens maintain body stiffness to sustain mate attractiveness but do not affect the surface properties that evoke the initial step of mate recognition, suggesting that males utilize multiple sensory mechanisms to recognize suitable mates. Manipulations of body stiffness via physical interventions, chemical treatments, and 3D-printed bionic worms indicate that body stiffness is a mechanical property for mate recognition and increases mating efficiency. Our study thus extends the repertoire of sensory cues of mate recognition in C. elegans and provides a paradigm to study the important roles of mechanosensory cues in social behaviors.

Ion-Dipole Interaction Enabling Highly Efficient CsPbI3 Perovskite Indoor Photovoltaics.

Metal halide perovskites are ideal candidates for indoor photovoltaics (IPVs) because of their easy-to-adjust bandgaps, which can be designed to cover the spectrum of any artificial light source. However, the serious non-radiative carrier recombination under low light illumination restrains the application of perovskite-based IPVs (PIPVs). Herein, polar molecules of amino naphthalene sulfonates are employed to functionalize the TiO2 substrate, anchoring the CsPbI3 perovskite crystal grains with a strong ion-dipole interaction between the molecule-level polar interlayer and the ionic perovskite film. The resulting high-quality CsPbI3 films with the merit of defect-immunity and large shunt resistance under low light conditions enable the corresponding PIPVs with an indoor power conversion efficiency of up to 41.2% (Pin : 334.11 µW cm-2 , Pout : 137.66 µW cm-2 ) under illumination from a commonly used indoor light-emitting diode light source (2956 K, 1062 lux). Furthermore, the device also achieves efficiencies of 29.45% (Pout : 9.80 µW cm-2 ) and 32.54% (Pout : 54.34 µW cm-2 ) at 106 (Pin : 33.84 µW cm-2 ) and 522 lux (Pin : 168.21 µW cm-2 ), respectively.

Association between Antihyperlipidemic Agent Use and Age-Related Macular Degeneration in Patients with Hyperlipidemia: A Population-Based Retrospective Cohort Study.

Several studies have indicated that lipoproteins might contribute to the pathogenesis of age-related macular degeneration (AMD). In this population-based retrospective cohort study, patients with hyperlipidemia were divided into two groups (study groups I and II) based on whether or not they were receiving antihyperlipidemic agents. The comparison group included patients without hyperlipidemia who were randomly selected and matched with study group II patients. A Cox proportional hazard model was used to evaluate the risk of AMD among the groups. Patients with hyperlipidemia receiving antihyperlipidemic agents (study group I, n = 15,482) had a significantly increased AMD risk (adjusted hazard ratio (HR) = 1.23, 95% confidence interval (CI) = 1.04-1.45) compared to those not receiving antihyperlipidemic agents (study group II, n = 15,482). However, with an increase in cumulative exposure, a reduced risk of AMD was observed in patients using a defined daily dose of more than 721, with an adjusted HR of 0.34 (95% CI = 0.22-0.53, p < 0.001). Additionally, the adjusted HR of AMD for study group II was 1.40 (95% CI = 1.20-1.63, p < 0.001) relative to the comparison group (n = 61,928). In conclusion, the study results indicated that patients with hyperlipidemia have a higher AMD risk than patients without hyperlipidemia. Furthermore, patients with hyperlipidemia who received antihyperlipidemic agents had a significantly increased AMD risk. However, a dose-dependent reduction in the risk of AMD was observed in patients with hyperlipidemia using statins or/and fibrates.

Rapid cancer cell perineural invasion utilizes amoeboid migration.

The invasion of nerves by cancer cells, or perineural invasion (PNI), is potentiated by the nerve microenvironment and is associated with adverse clinical outcomes. However, the cancer cell characteristics that enable PNI are poorly defined. Here, we generated cell lines enriched for a rapid neuroinvasive phenotype by serially passaging pancreatic cancer cells in a murine sciatic nerve model of PNI. Cancer cells isolated from the leading edge of nerve invasion showed a progressively increasing nerve invasion velocity with higher passage number. Transcriptome analysis revealed an upregulation of proteins involving the plasma membrane, cell leading edge, and cell movement in the leading neuroinvasive cells. Leading cells progressively became round and blebbed, lost focal adhesions and filipodia, and transitioned from a mesenchymal to amoeboid phenotype. Leading cells acquired an increased ability to migrate through microchannel constrictions and associated more with dorsal root ganglia than nonleading cells. ROCK inhibition reverted leading cells from an amoeboid to mesenchymal phenotype, reduced migration through microchannel constrictions, reduced neurite association, and reduced PNI in a murine sciatic nerve model. Cancer cells with rapid PNI exhibit an amoeboid phenotype, highlighting the plasticity of cancer migration mode in enabling rapid nerve invasion.

Low-Dimensional Phase Regulation to Restrain Non-Radiative Recombination for Sky-Blue Perovskite LEDs with EQE Exceeding 15 .

Achieving efficient blue electroluminescence (EL) remains the fundamental challenge that impedes perovskite light-emitting diodes (PeLEDs) towards commercial applications. The bottleneck accounting for the inefficient blue PeLEDs is broadly attributed to the poor-emissive blue perovskite emitters based on either mixed halide engineering or reduced-dimensional strategy. Herein, we report the high-performing sky-blue PeLEDs (490 nm) with the maximum EQE exceeding 15 % by incorporating a molecular modifier, namely 4,4'-Difluorophenone, for significantly suppressing the non-radiative recombination and tuning of the low-dimensional phase distribution of quasi-2D blue perovskites, which represents a remarkable paradigm for developing the new generation of blue lighting sources.

Efficient Near-Infrared Electroluminescence from Lanthanide-Doped Perovskite Quantum Cutters.

Perovskite nanocrystals (PeNCs) deliver size- and composition-tunable luminescence of high efficiency and color purity in the visible range. However, attaining efficient electroluminescence (EL) in the near-infrared (NIR) region from PeNCs is challenging, limiting their potential applications. Here we demonstrate a highly efficient NIR light-emitting diode (LED) by doping ytterbium ions into a PeNCs host (Yb3+ : PeNCs), extending the EL wavelengths toward 1000 nm, which is achieved through a direct sensitization of Yb3+ ions by the PeNC host. Efficient quantum-cutting processes enable high photoluminescence quantum yields (PLQYs) of up to 126 % from the Yb3+ : PeNCs. Through halide-composition engineering and surface passivation to improve both PLQY and charge-transport balance, we demonstrate an efficient NIR LED with a peak external quantum efficiency of 7.7 % at a central wavelength of 990 nm, representing the most efficient perovskite-based LEDs with emission wavelengths beyond 850 nm.

Surgical Technique for Superior Cervical Ganglionectomy in a Murine Model.

Growing evidence suggests that the sympathetic nervous system plays an important role in cancer progression. Adrenergic innervation regulates salivary gland secretion, circadian rhythm, macular degeneration, immune function, and cardiac physiology. Murine surgical sympathectomy is a method for studying the effects of adrenergic innervation by allowing for complete, unilateral adrenergic ablation while avoiding the need for repeated pharmacologic intervention and the associated side effects. However, surgical sympathectomy in mice is technically challenging because of the small size of the superior cervical ganglion. This study describes a surgical technique for reliably identifying and resecting the superior cervical ganglion to ablate the sympathetic nervous system. The successful identification and removal of the ganglion are validated by imaging the fluorescent sympathetic ganglia using a transgenic mouse, identifying post-resection Horner's syndrome, staining for adrenergic markers in the resected ganglia, and observing diminished adrenergic immunofluorescence in the target organs following sympathectomy. This model enables future studies of cancer progression as well as other physiological processes regulated by the sympathetic nervous system.

The Effect of Oxalic Acid as the Pre-Activator for the Electropolishing of Additive Manufactured Titanium-Based Materials and Its Characterization.

The use of additive manufactured (AM) titanium-based materials has increased substantially for medical implants and aerospace components. However, the inferior surface roughness of additive manufactured products affects the outward appearance and reduces performance. This study determines whether activation treatment prior to electropolishing produces a better surface. Oxalic acid (OA) is used as a pre-activator using different experimental conditions and the surface roughness is reduced by electropolishing with an electrolyte of perchloric acid and glacial acetic acid. The SEM surface morphology, mechanical properties, phase transformation and electrochemical properties are measured to determine the effect of different degrees of roughness on the surface. The results show that the surface roughness of AM titanium-based samples decreases from 8.47 µm to 1.09 µm after activation using OA as a pre-treatment for electropolishing. After electropolishing using optimal parameters, the hardness and resistance to corrosion resistance are increased.

Light-Triggered Sustainable Defect-Passivation for Stable Perovskite Photovoltaics.

The generation of photoinduced defects and freely moving halogen ions is dynamically updated in real time. Accordingly, most reported strategies are static and short-term, which make their improvements in photostability very limited. Therefore, seeking new passivation strategies to match the dynamic characteristics of defect generation is very urgent. Without newly generated defects, a passivation molecule should exist in the configuration that would not become the initiation sites for defect generation. With newly generated defects, the passivation molecule should transfer into the other configuration that possesses the passivation sites. Herein, a classical photoisomeric molecule, spiropyran, is adopted, whose pre- and post-isomeric forms meet the requirements for two different configurations, to realize the state transition once the photoinduced defects appear during subsequent operation and dynamic capture for continuous renewal of defects. Consequently, spiropyrans work as light-triggered and self-healing sustainable passivation sites to realize continuous defect repair. The target devices retain 93% and 99% of their initial power conversion efficiencies after 456 h aging under ultraviolet illumination and 1200 h aging under full-spectrum illumination, respectively. This work provides a novel concept of sustainable passivation strategy to realize continuous defect-passivation and film-healing in perovskite photovoltaics.

Reprogrammed Schwann Cells Organize into Dynamic Tracks that Promote Pancreatic Cancer Invasion.

Nerves are a component of the tumor microenvironment contributing to cancer progression, but the role of cells from nerves in facilitating cancer invasion remains poorly understood. Here we show that Schwann cells (SC) activated by cancer cells collectively function as tumor-activated Schwann cell tracks (TAST) that promote cancer cell migration and invasion. Nonmyelinating SCs form TASTs and have cell gene expression signatures that correlate with diminished survival in patients with pancreatic ductal adenocarcinoma. In TASTs, dynamic SCs form tracks that serve as cancer pathways and apply forces on cancer cells to enhance cancer motility. These SCs are activated by c-Jun, analogous to their reprogramming during nerve repair. This study reveals a mechanism of cancer cell invasion that co-opts a wound repair process and exploits the ability of SCs to collectively organize into tracks. These findings establish a novel paradigm of how cancer cells spread and reveal therapeutic opportunities. SIGNIFICANCE: How the tumor microenvironment participates in pancreatic cancer progression is not fully understood. Here, we show that SCs are activated by cancer cells and collectively organize into tracks that dynamically enable cancer invasion in a c-Jun-dependent manner. See related commentary by Amit and Maitra, p. 2240. This article is highlighted in the In This Issue feature, p. 2221.

Visualizing the Surface Photocurrent Distribution in Perovskite Photovoltaics.

Defect states play an important role in the photovoltaic performance of metal halide perovskites. Particularly, the passivation of surface defects has made great contributions to high-performance perovskite photovoltaics. This highlights the importance of understanding the surface defects from a fundamental level by developing more accurate and operando characterization techniques. Herein, a strategy to enable the surface carriers and photocurrent distributions on perovskite films to be visualized in the horizontal direction is put forward. The visual image of photocurrent distribution is realized by combining the static local distribution of carriers provided by scanning near-field optical microscopy with the dynamic transporting of carriers achieved via a scanning photocurrent measurement system. Taking a surface passivated molecule as an example, a comprehensive defect scene including static and dynamic as well as local and entire conditions is obtained using this strategy. The comprehensive analysis of the trap states in perovskite films is pioneered vertically and horizontally, which will powerfully promote the deep understanding of defect mechanisms and carrier behavior for the goal of fabricating high-performance perovskite optoelectronic devices.