Explore the vast range of titles available.

Cell-cell and cell-matrix mechanical interactions through membrane receptors direct a wide range of cellular functions and orchestrate the development of multicellular organisms. To define the single molecular forces required to activate signaling through a ligand-receptor bond, we developed the tension gauge tether (TGT) approach in which the ligand is immobilized to a surface through a rupturable tether before receptor engagement. TGT serves as an autonomous gauge to restrict the receptor-ligand tension. Using a range of tethers with tunable tension tolerances, we show that cells apply a universal peak tension of about 40 piconewtons (pN) to single integrin-ligand bonds during initial adhesion. We find that less than 12 pN is required to activate Notch receptors. TGT can also provide a defined molecular mechanical cue to regulate cellular functions.

The stable operation of lithium-based batteries at low temperatures is critical for applications in cold climates. However, low-temperature operations are plagued by insufficient dynamics in the bulk of the electrolyte and at electrode|electrolyte interfaces. Here, we report a quasi-solid-state polymer electrolyte with an ionic conductivity of 2.2 × 10 −4 S cm −1 at −20 °C. The electrolyte is prepared via in situ polymerization using a 1,3,5-trioxane-based precursor. The polymer-based electrolyte enables a dual-layered solid electrolyte interphase formation on the Li metal electrode and stabilizes the LiNi 0.8 Co 0.1 Mn 0.1 O 2 -based positive electrode, thus improving interfacial charge-transfer at low temperatures. Consequently, the growth of dendrites at the lithium metal electrode is hindered, thus enabling stable Li||LiNi 0.8 Co 0.1 Mn 0.1 O 2 coin and pouch cell operation even at −30 °C. In particular, we report a Li||LiNi 0.8 Co 0.1 Mn 0.1 O 2 coin cell cycled at −20 °C and 20 mA g −1 capable of retaining more than 75% (i.e., around 151 mAh g −1 ) of its first discharge capacity cycle at 30 °C and same specific current. Low-temperature batteries are detrimentally affected by the sluggish kinetics of the electrolyte. Here, the authors propose a quasi-solid-state polymer electrolyte capable of improving interfacial charge transfer and enabling stable Li metal cell operation even at −30 °C.

Immunoglobulin has been widely used in a variety of diseases, including primary and secondary immunodeficiency diseases, neuromuscular diseases, and Kawasaki disease. Although a large number of clinical trials have demonstrated that immunoglobulin is effective and well tolerated, various adverse effects have been reported. The majority of these events, such as flushing, headache, malaise, fever, chills, fatigue and lethargy, are transient and mild. However, some rare side effects, including renal impairment, thrombosis, arrhythmia, aseptic meningitis, hemolytic anemia, and transfusion-related acute lung injury (TRALI), are serious. These adverse effects are associated with specific immunoglobulin preparations and individual differences. Performing an early assessment of risk factors, infusing at a slow rate, premedicating, and switching from intravenous immunoglobulin (IVIG) to subcutaneous immunoglobulin (SCIG) can minimize these adverse effects. Adverse effects are rarely disabling or fatal, treatment mainly involves supportive measures, and the majority of affected patients have a good prognosis.

High-performance Li-ion/metal batteries working at a low temperature (i.e., <−20 °C) are desired but hindered by the sluggish kinetics associated with Li + transport and charge transfer. Herein, the temperature-dependent Li + behavior during Li plating is profiled by various characterization techniques, suggesting that Li + diffusion through the solid electrolyte interface (SEI) layer is the key rate-determining step. Lowering the temperature not only slows down Li + transport, but also alters the thermodynamic reaction of electrolyte decomposition, resulting in different reaction pathways and forming an SEI layer consisting of intermediate products rich in organic species. Such an SEI layer is metastable and unsuitable for efficient Li + transport. By tuning the solvation structure of the electrolyte with a lower lowest unoccupied molecular orbital (LUMO) energy level and polar groups, such as fluorinated electrolytes like 1 mol L −1 lithium bis(fluorosulfonyl)imide (LiFSI) in methyl trifluoroacetate (MTFA): fluoroethylene carbonate (FEC) (8:2, weight ratio), an inorganic-rich SEI layer more readily forms, which exhibits enhanced tolerance to a change of working temperature (thermodynamics) and improved Li + transport (kinetics). Our findings uncover the kinetic bottleneck for Li + transport at low temperature and provide directions to enhance the reaction kinetics/thermodynamics and low-temperature performance by constructing inorganic-rich interphases. High-performance lithium metal batteries operating below −20 °C are desired but hindered by slow reaction kinetics. Here, the authors uncover the temperature-dependent Li + behavior and interphase formation in liquid electrolytes and provide directions to enhance the low temperature performance.

Heterobimetallic iron-group 9 carbonyl cations, FeM(CO) (M = Rh, Ir; = 9-11), were generated in the gas phase via pulsed laser vaporization within a supersonic expansion and characterized by infrared photodissociation spectroscopy in the carbonyl stretching region. By combining experimental spectra with density functional theory simulations, the geometric and electronic structures of these clusters were unambiguously assigned. Mass spectrometry and photodissociation results identified FeM(CO) as the saturated species for M = Rh and Ir, in contrast to the lighter cobalt analog FeCo(CO) . The FeM(CO) cations adopt a C -symmetric singlet ground-state structure with all carbonyl ligands terminally bound, corresponding to a (OC) Fe-M(CO) configuration. These complexes can be formally described as combination products of the stable neutral Fe(CO) and cationic M(CO) fragments. Analyses based on canonical molecular orbitals, Mayer bond orders, and fragment-based correlation diagrams reveal the presence of a dative Fe→M interaction in FeM(CO) , which formally enables the heavier Rh/Ir metal center to attain an 18-electron configuration. However, this bond is weaker than a typical covalent single bond, as the key molecular orbitals involved possess antibonding character. This study provides important insights into the structure and bonding of heteronuclear transition metal carbonyl clusters, highlighting distinctive coordination behavior between late 3 and heavier 4 /5 congeners.

Magnetic topological insulators (MTIs) offer a combination of topologically nontrivial characteristics and magnetic order and show promise in terms of potentially interesting physical phenomena such as the quantum anomalous Hall (QAH) effect and topological axion insulating states. However, the understanding of their properties and potential applications have been limited due to a lack of suitable candidates for MTIs. Here, we grow two-dimensional single crystals of Mn(Sb x Bi (1- x ) ) 2 Te 4 bulk and exfoliate them into thin flakes in order to search for intrinsic MTIs. We perform angle-resolved photoemission spectroscopy, low-temperature transport measurements, and first-principles calculations to investigate the band structure, transport properties, and magnetism of this family of materials, as well as the evolution of their topological properties. We find that there exists an optimized MTI zone in the Mn(Sb x Bi (1- x ) ) 2 Te 4 phase diagram, which could possibly host a high-temperature QAH phase, offering a promising avenue for new device applications. Available intrinsic magnetic topological insulators are rare. Here, the authors study the electronic and magnetic properties of Mn(Sb x Bi (1- x ) ) 2 Te 4 bulks and thin flakes, revealing intrinsic magnetic topological insulator phase in the phase diagram.

Reasonable cultivation is an important part of the protection work of endangered species. The timely and nondestructive monitoring of chlorophyll can provide a basis for the accurate management and intelligent development of cultivation. The image analysis method has been applied in the nutrient estimation of many economic crops, but information on endangered tree species is seldom reported. Moreover, shade control, as the common seedling management measure, has a significant impact on chlorophyll, but shade levels are rarely discussed in chlorophyll estimation and are used as variables to improve model accuracy. In this study, 2-year-old seedlings of tropical and endangered Hopea hainanensis were taken as the research object, and the SPAD value was used to represent the relative chlorophyll content. Based on the performance comparison of RGB and multispectral (MS) images using different algorithms, a low-cost SPAD estimation method combined with a machine learning algorithm that is adaptable to different shade conditions was proposed. The SPAD values changed significantly at different shade levels ( p  < 0.01), and 50% shade in the orthographic direction was conducive to chlorophyll accumulation in seedling leaves. The coefficient of determination ( R 2 ), root mean square error (RMSE), and average absolute percent error (MAPE) were used as indicators, and the models with dummy variables or random effects of shade greatly improved the goodness of fit, allowing better adaption to monitoring under different shade conditions. Most of the RGB and MS vegetation indices (VIs) were significantly correlated with the SPAD values, but some VIs exhibited multicollinearity (variance inflation factor (VIF) > 10). Among RGB VIs, RGRI had the strongest correlation, but multiple VIs filtered by the Lasso algorithm had a stronger ability to interpret the SPAD data, and there was no multicollinearity (VIF < 10). A comparison of the use of multiple VIs to estimate SPAD indicated that Random forest (RF) had the highest fitting ability, followed by Support vector regression (SVR), linear mixed effect model (LMM), and ordinary least squares regression (OLR). In addition, the performance of MS VIs was superior to that of RGB VIs. The R 2 of the optimal model reached 0.9389 for the modeling samples and 0.8013 for the test samples. These findings reinforce the effectiveness of using VIs to estimate the SPAD value of H. hainanensis under different shade conditions based on machine learning and provide a reference for the selection of image data sources.

Electrolyte engineering advances Li metal batteries (LMBs) with high Coulombic efficiency (CE) by constructing LiF-rich solid electrolyte interphase (SEI). However, the low conductivity of LiF disturbs Li + diffusion across SEI, thus inducing Li + transfer-driven dendritic deposition. In this work, we establish a mechanistic model to decipher how the SEI affects Li plating in high-fluorine electrolytes. The presented theory depicts a linear correlation between the capacity loss and current density to identify the slope k (determined by Li + mobility of SEI components) as an indicator for describing the homogeneity of Li + flux across SEI, while the intercept dictates the maximum CE that electrolytes can achieve. This model inspires the design of an efficient electrolyte that generates dual-halide SEI to homogenize Li + distribution and Li deposition. The model-driven protocol offers a promising energetic analysis to evaluate the compatibility of electrolytes to Li anode, thus guiding the design of promising electrolytes for LMBs. The low conductivity of LiF disturbs Li + diffusion across solid electrolyte interphase (SEI) and induces Li + transfer-driven dendritic growth. Herein, the authors establish a mechanistic model to decipher how the SEI affects realistic Li plating in high-fluorine electrolytes.

Elevating the charging cut-off voltage is one of the efficient approaches to boost the energy density of Li-ion batteries (LIBs). However, this method is limited by the occurrence of severe parasitic reactions at the electrolyte/electrode interfaces. Herein, to address this issue, we design a non-flammable fluorinated sulfonate electrolyte by multifunctional solvent molecule design, which enables the formation of an inorganic-rich cathode electrolyte interphase (CEI) on high-voltage cathodes and a hybrid organic/inorganic solid electrolyte interphase (SEI) on the graphite anode. The electrolyte, consisting of 1.9 M LiFSI in a 1:2  v / v mixture of 2,2,2-trifluoroethyl trifluoromethanesulfonate and 2,2,2-trifluoroethyl methanesulfonate, endows 4.55 V-charged graphite||LiCoO 2 and 4.6 V-charged graphite||NCM811 batteries with capacity retentions of 89% over 5329 cycles and 85% over 2002 cycles, respectively, thus resulting in energy density increases of 33% and 16% compared to those charged to 4.3 V. This work demonstrates a practical strategy for upgrading the commercial LIBs. The parasitic reactions at the electrolyte/electrode interfaces inhibit the increase of the charging cut-off voltage and the improvement of energy density. Herein, the authors design multifunctional solvent molecules and propose a practical design principle to stabilize the electrolyte/electrode interfaces for high-voltage Li ion batteries.

The geometric structure and bonding features of dinuclear vanadium-group transition metal carbonyl cation complexes in the form of VM(CO)n+ (n = 9–11, M = V, Nb, and Ta) are studied by infrared photodissociation spectroscopy in conjunction with density functional calculations. The homodinuclear V2(CO)9+ is characterized as a quartet structure with CS symmetry, featuring two side-on bridging carbonyls and an end-on semi-bridging carbonyl. In contrast, for the heterodinuclear VNb(CO)9+ and VTa(CO)9+, a C2V sextet isomer with a linear bridging carbonyl is determined to coexist with the lower-lying CS structure analogous to V2(CO)9+. Bonding analyses manifest that the detected VM(CO)9+ complexes featuring an (OC)6M–V(CO)3 pattern can be regarded as the reaction products of two stable metal carbonyl fragments, and indicate the presence of the M–V d-d covalent interaction in the CS structure of VM(CO)9+. In addition, it is demonstrated that the significant activation of the bridging carbonyls in the VM(CO)9+ complexes is due in large part to the diatomic cooperation of M–V, where the strong oxophilicity of vanadium is crucial to facilitate its binding to the oxygen end of the carbonyl groups. The results offer important insight into the structure and bonding of dinuclear vanadium-containing transition metal carbonyl cluster cations and provide inspiration for the design of active vanadium-based diatomic catalysts.