Alzheimer's disease is a neurodegenerative disorder characterized by the extracellular deposition in the brain of aggregated ␤ -amyloid peptide, presumed to play a pathogenic role, and by preferential loss of neurons that express the 75-kD neurotrophin receptor (p75 NTR ). Using rat cortical neurons and NIH-3T3 cell line engineered to stably express p75 NTR , we find that the ␤ -amyloid peptide specifically binds the p75 NTR . Furthermore, 3T3 cells expressing p75 NTR , but not wild-type control cells lacking the receptor, undergo apoptosis in the presence of aggregated ␤ -amyloid. Normal neural crest-derived melanocytes that express physiologic levels of p75 NTR undergo apoptosis in the presence of aggregated ␤ -amyloid, but not in the presence of control peptide synthesized in reverse. These data imply that neuronal death in Alzheimer's disease is mediated, at least in part, by the interaction of ␤ -amyloid with p75 NTR , and suggest new targets for therapeutic intervention. ( J. Clin. Invest. 1997.

The application of graphene-based membranes is hindered by their poor stability under practical hydrodynamic conditions. Here, nanocarbon architectures are designed by intercalating surface-functionalized, small-diameter, multi-walled carbon nanotubes (MWCNTs) into reduced graphene oxide (rGO) sheets to create highly stable membranes with improved water permeability and enhanced membrane selectivity. With the intercalation of 10 nm diameter MWCNTs, the water permeability reaches 52.7 L m −2 h −1 bar −1 , which is 4.8 times that of pristine rGO membrane and fi ve to ten times higher than most commercial nanofi ltration membranes. The membrane also attains almost 100% rejection for three organic dyes of different charges. More importantly, the membrane can endure a turbulent hydrodynamic fl ow with cross-fl ow rates up to 2000 mL min −1 and a Reynolds number of 4667. Physicochemical characterization reveals that the inner graphitic walls of the MWCNTs can serve as spacers, while nanoscale rGO foliates on the outer walls interconnect with the assimilated rGO sheets to instill superior membrane stability. In contrast, intercalating with single-walled nanotubes fails to reproduce such stability. Overall, this nanoarchitectured design is highly versatile in creating both graphene-rich and CNT-rich all-carbon membranes with engineered nanochannels, and is regarded as a general approach in obtaining stable membranes for realizing practical applications of graphenebased membranes.

Metal oxides of earth-abundant elements are promising electrocatalysts to overcome the sluggish oxygen evolution and oxygen reduction reaction (OER/ORR) in many electrochemical energy-conversion devices. However, it is difficult to control their catalytic activity precisely. Here, a general three-stage synthesis strategy is described to produce a family of hybrid materials comprising amorphous bimetallic oxide nanoparticles anchored on N-doped reduced graphene oxide with simultaneous control of nanoparticle elemental composition, size, and crystallinity. Amorphous Fe Co O is obtained from Prussian blue analog nanocrystals, showing excellent OER activity with a Tafel slope of 30.1 mV dec and an overpotential of 257 mV for 10 mA cm and superior ORR activity with a large limiting current density of -5.25 mA cm at 0.6 V. A fabricated Zn-air battery delivers a specific capacity of 756 mA h g (corresponding to an energy density of 904 W h kg ), a peak power density of 86 mW cm and can be cycled over 120 h at 10 mA cm . Other two amorphous bimetallic, Ni Fe O and Ni Co O , are also produced to demonstrate the general applicability of this method for synthesizing binary metal oxides with controllable structures as electrocatalysts for energy conversion.

p75NTR , a nerve growth factor co-receptor that has been implicated in apoptosis of neurons, is structurally related to Fas and the receptors for tumor necrosis factor-␣ that display ligand independent assembly into trimers. Using embryonic day 17 fetal rat cortical neurons and p75 NTR -expressing NIH-3T3 cells, we now show that p75 NTR exists as a trimer as well as a monomer. Furthermore, we have reported and others have confirmed that amyloid ␤ binds p75 NTR , and that this binding leads to apoptotic cell death. We now report that amyloid ␤ binds to trimers of p75 NTR as well as to p75 NTR monomers but not to the p140 trkA , the nerve growth factor co-receptor that mediates neuronal survival. Furthermore, amyloid ␤ activates p75 NTR , strongly inducing the transcription of c-Jun mRNA and stimulating the stress-activated c-Jun NH 2 -terminal kinase, as measured by phosphorylation of its substrate (glutathione S-transferase-c-Jun-(1-79)). Our data suggest that p75 NTR may be present as a preformed trimer that binds amyloid ␤ to induce receptor activation, and support the hypothesis that p75 NTR activation by amyloid ␤ is causally related to Alzheimer's disease.

A facile activation strategy can transform pristine carbon fiber tows into high-performance fiber electrodes with a specific capacitance of 14.2 F cm(-3) . The knottable fiber supercapacitor shows an energy density of 0.35 mW h cm(-3) , an ultrahigh power density of 3000 mW cm(-3) , and a remarkable capacitance retention of 68%, when the scan rate increases from 10 to 1000 mV s(-1) .

Customized hybrid carbon fiber supercapacitors with energy across two orders and power across four orders of magnitude.

We have recently shown that (a) human melanocytes express the p75 nerve growth factor (NGF) receptor in vitro; (b) that melanocyte dendricity and migration, among other behaviors, are regulated at least in part by NGF; and (c) that cultured human epidermal keratinocytes produce NGF. We now report that melanocyte stimulation with phorbol 12-tetra decanoate 13-acetate (TPA), previously reported to induce p75 NGF receptor, also induces trk in melanocytes, and TPA effect is further potentiated by the presence of keratinocytes in culture. Moreover, trk in melanocytes becomes phosphorylated within minutes after NGF stimulation. As well, cultures of dermal fibroblasts express neurotrophin-3 (NT-3) mRNA; NT-3 mRNA levels in cultured fibroblasts are modulated by mitogenic stimulation, UV irradiation, and exposure to melanocyte-conditioned medium. Moreover, melanocytes constitutively express low levels of trk-C, and its expression is downregulated after TPA stimulation. NT-3 supplementation to cultured melanocytes maintained in Medium 199 alone prevents cell death. These combined data suggest that melanocyte behavior in human skin may be influenced by neurotrophic factors, possibly of keratinocyte and fibroblast origin, which act through high affinity receptors. (J. Clin. Invest. 1994. 94:1550-1562

considering their potential for performing even more complex functions. In particular, the recent booming of the "internet of things" and "artificial intelligence" further encourages the development of a new generation of wearable devices. [4] Accordingly, we need reliable and compact yet high-performance energy storage systems to power emerging electronics. Plus, the mechanical characteristics of the systems should support a pleasant user experience in terms of wearability. Recently, the 1D energy storage devices, especially 1D supercapacitors (SCs), have emerged as a promising candidate. [5][6][7][8][9][10][11] 1D SCs are elongated (fiber/yarn/wire/ cable-like) structures with dimensions typically ranging from tens to hundreds of micrometers in diameter, and several millimeters to meters in length. Their 1D structures offer various advantages over their conventionally rigid and bulky counterparts: 1) they show a higher degree of mechanical flexibility (which helps withstand long-term and repetitive deformations); 2) allow easy scaling up by self-integration (which is useful for meeting a wide range of power requirements); 3) are easily packed into small spaces with diverse shapes (which brings design versatility); and 4) have shape advantage for integrating with other 1D devices (which is preferable for the fabrication of multifunctional wearable systems). [5,9,10,12] Further, 1D SCs also have several potential advantages over other emerging 1D energy storage devices, especially, 1D batteries. 1) 1D SCs have unique energy storage characteristics. They can provide superior power density and faster charging/discharging rates than 1D batteries. Also, their energy density is gradually catching up that of 1D batteries with the uses of intercalative and extrinsic pseudocapacitive materials in electrodes. [13] 2) 1D SCs are often superior in their safety and environmental friendliness. Batteries, e.g., Li-ion batteries, typically comprise of hazardous, organic electrolytes, which is harmful to the human body if they leak. Organic electrolytes are also prone to fire or even explosion. In contrast, 1D SCs based on aqueous polymer gel electrolytes are much safer and more environmentally friendly. 3) 1D SCs may work in a wider operating temperature window when suitable electrolytes are used, which extends their potential usages in emerging electronics at different environmental conditions. In contrast, redox reactions in batteries often can only work in a narrow temperature window. 4) 1D SCs may offer longer lifespan to avoid frequent battery replacement in practical application. [14,15] 1D supercapacitors (SCs) have emerged as promising candidates to power emerging electronics in recent years because of their unique advantages in energy storage and mechanical flexibility. There are four main research fronts in the development of 1D SCs: 1) enhancing mechanical characteristics, 2) achieving superior electrochemical performance, 3) enabling multiple device integration, and 4) demonstrating multifunctionality. Here, a brief...