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.
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.
Two-dimensional (2D) transition-metal dichalcogenides hold enormous potential for applications in electronic and optoelectronic devices. Their distinctive electronic and chemical properties are ...closely related to the structure and intercalation chemistry. Herein, the controversial phase transition from semiconductive 2H to metallic 1T phase and occupancy of the intercalated sodium (Na) upon electrochemical Na intercalation into MoS2 are clarified at the atomic scale by aberration-corrected scanning transmission electron microscope. In addition, a series of other complicated phase transitions along with lattice distortion, structural modulation, and even irreversible structural decomposition are recognized in MoS2 depending on the content of Na ion intercalation. It is shown that x = 1.5 in Na x MoS2 is a critical point for the reversibility of the structural evolution. Our findings enrich the understanding of the phase transitions and intercalation chemistry of the MoS2 and shed light on future material design and applications.
MXenes represent a large family of functionalized two-dimensional (2D) transition-metal carbides and carbonitrides. However, most of the understanding on their unique structures and applications ...stops at the theoretical suggestion and lack of experimental support. Herein, the surface structure and intercalation chemistry of Ti3C2X are clarified at the atomic scale by aberration-corrected scanning transmission electron microscope (STEM) and density functional theory (DFT) calculations. The STEM studies show that the functional groups (e.g., OH–, F–, O–) and the intercalated sodium (Na) ions prefer to stay on the top sites of the centro-Ti atoms and the C atoms of the Ti3C2 monolayer, respectively. Double Na-atomic layers are found within the Ti3C2X interlayer upon extensive Na intercalation via two-phase transition and solid-solution reactions. In addition, aluminum (Al)-ion intercalation leads to horizontal sliding of the Ti3C2X monolayer. On the basis of these observations, the previous monolayer surface model of Ti3C2X is modified. DFT calculations using the new modeling help to understand more about their physical and chemical properties. These findings enrich the understanding of the MXenes and shed light on future material design and applications. Moreover, the Ti3C2X exhibits prominent rate performance and long-term cycling stability as an anode material for Na-ion batteries.
A reduced graphene oxide (rGO) based film is sandwiched between a sulfur cathode and the separator, acting as a shuttle inhibitor to the sulfur and polysulfides. The lithium–sulfur cell with such a ...configuration shows an initial discharge capacity of 1260 mAh g−1 and the capacity remains at 895 mAh g−1 after 100 cycles. The excellent electrochemical performance of the cell is attributed to both the functional groups on the rGO sheets that anchor the sulfur and polysulfides and the carbon additive that helps to produce channels for the electrolyte and polysulfide to enter.
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•A reduced graphene oxide (rGO) based interlayer is used as a shuttle inhibitor.•The rGO interlayer improves the cycling performance of the Li–S cell significantly.•Functional groups on the rGO help to anchor the sulfur and polysulfides.•Compromise is required between anchoring sulfides and building electrolyte channels.
Highlights • Ketamine plays an anticonvulsant role via antagonism of NMDA receptors. • Ketamine appears to be effective on refractory SE but based on low level of evidence. • Ketamine is often ...selected after 5–6 anticonvulsants have failed. • Ketamine administration involves intravenous and oral routes. • Ketamine is rapid onset and relatively safe for refractory status epilepticus.
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
S cm
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
Co
Mn
O
-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
Co
Mn
O
coin and pouch cell operation even at -30 °C. In particular, we report a Li||LiNi
Co
Mn
O
coin cell cycled at -20 °C and 20 mA g
capable of retaining more than 75% (i.e., around 151 mAh g
) of its first discharge capacity cycle at 30 °C and same specific current.
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.
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