Saponin adjuvants have been extensively studied for their use in veterinary and human vaccines. Among them, QS-21 stands out owing to its unique profile of immunostimulating activity, inducing a ...balanced Th1/Th2 immunity, which is valuable to a broad scope of applications in combating various microbial pathogens, cancers, and other diseases. It has recently been approved for use in human vaccines as a key component of combination adjuvants, e.g., AS01b in Shingrix
for herpes zoster. Despite its usefulness in research and clinic, the cellular and molecular mechanisms of QS-21 and other saponin adjuvants are poorly understood. Extensive efforts have been devoted to studies for understanding the mechanisms of QS-21 in different formulations and in different combinations with other adjuvants, and to medicinal chemistry studies for gaining mechanistic insights and development of practical alternatives to QS-21 that can circumvent its inherent drawbacks. In this review, we briefly summarize the current understandings of the mechanism underlying QS-21's adjuvanticity and the encouraging results from recent structure-activity-relationship (SAR) studies.
Asset Bubbles and Credit Constraints Miao, Jianjun; Wang, Pengfei
The American economic review,
09/2018, Letnik:
108, Številka:
9
Journal Article
Recenzirano
Odprti dostop
We provide a theory of rational stock price bubbles in production economies with infinitely-lived agents. Firms meet stochastic investment opportunities and face endogenous credit constraints. They ...are not fully committed to repaying debt. Credit constraints are derived from incentive constraints in optimal contracts which ensure default never occurs in equilibrium. Stock price bubbles can emerge through a positive feedback loop mechanism and cannot be ruled out by transversality conditions. These bubbles command a liquidity premium and raise investment by raising the debt limit. Their collapse leads to a recession and a stock market crash.
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•Structurally simple and practically useful PPGs are developed.•The PPGs release various functional groups efficiently.•Photo deprotection can occur in organic, aqueous, and solid ...phase.•The PPGs are easy to prepare and install, with remarkable dark stability.
We have recently developed a number of photolabile protecting groups (PPGs) for efficient release of carbonyl, hydroxyl, diol, carboxyl, and amino functionalities. These new PPGs are designed on the basis of the excited state meta effect. They share common features including structural simplicity, easy preparation, flexible structural modification, diverse protection methods, high protection and deprotection efficiency, tolerance of ambient conditions during irradiation, and remarkable stability toward chemical treatments. They can be potentially useful in a wide range of applications including organic synthesis, caging, and materials science.
Direct solar steam generation (DSSG) offers a promising, sustainable, and environmentally friendly solution to the energy and water crisis. In the past decades, DSSG has gained tremendous attention ...due to its potential applications for clean water production, desalination, wastewater treatment, and electric energy harvesting. Even though the solar–thermal conversion efficiency has approached 100% under 1 sun illumination (1 kW m−2) using various photothermal materials and systems, the optimization of the materials and system structure remains unclear because of the lack of evaluation methods in unity for the output efficiency. In this review, a few key concerns about different dimensional materials and systems that determine the characteristics of DSSG are explored. Quantitative analysis, including calculations and methods for the solar–thermal conversion efficiency, evaporation rate, and energy loss, is employed to evaluate the materials and systems from the point of view of ultimate utilization. This article focuses on the relationship between the system dimension and energy efficiency and notes opportunities for future system design and commercialization of DSSG.
Direct solar steam generation requires multifunctional materials for powerful light absorption, well‐performing heat management, and sufficient water transport ability. The development and evolution of materials and system structures from 0D to 3D are summarized. Performance evaluations including efficiency, evaporation rate, and heat loss calculations, along with multifunctional utilizations, are highlighted.
This Review focuses on the structure‐reactivity relationship of three main classes of photolabile protecting groups (PPGs), that is, the 2‐nitrobenzyl (NB) series of PPGs, carbonyl‐based PPGs, and ...benzyl‐based PPGs. Recent efforts in developing new PPGs for protection of carbonyl and hydroxy groups are also discussed.
A snapshot: The structure‐reactivity relationship of three classes of widely used photolabile protecting groups (PPGs), the 2‐nitrobenzyl series of PPGs, carbonyl‐based PPGs, and benzyl‐based PPGs, is summarized. Recent efforts in developing new salicyl‐based carbonyl PPGs and trityl‐based PPGs for direct release of alcohols from PPG‐protected hydroxy groups are also discussed.
Using the forward period analysis (FPA), we obtain the period of a Morse oscillator and mathematical pendulum system, with the accuracy of 100 significant digits. From these results, the long-term 0, ...1060 (time unit) solutions, ranging from the Planck time to the age of the universe, are computed reliably and quickly with a parallel multiple-precision Taylor series (PMT) scheme. The application of FPA to periodic systems can greatly reduce the computation time of long-term reliable simulations. This scheme provides an efficient way to generate reference solutions, against which long-term simulations using other schemes can be tested.
All‐solid‐state Li metal batteries have attracted extensive attention due to their high safety and high energy density. However, Li dendrite growth in solid‐state electrolytes (SSEs) still hinders ...their application. Current efforts mainly aim to reduce the interfacial resistance, neglecting the intrinsic dendrite‐suppression capability of SSEs. Herein, the mechanism for the formation of Li dendrites is investigated, and Li‐dendrite‐free SSE criteria are reported. To achieve a high dendrite‐suppression capability, SSEs should be thermodynamically stable with a high interface energy against Li, and they should have a low electronic conductivity and a high ionic conductivity. A cold‐pressed Li3N–LiF composite is used to validate the Li‐dendrite‐free design criteria, where the highly ionic conductive Li3N reduces the Li plating/stripping overpotential, and LiF with high interface energy suppresses dendrites by enhancing the nucleation energy and suppressing the Li penetration into the SSEs. The Li3N–LiF layer coating on Li3PS4 SSE achieves a record‐high critical current of >6 mA cm−2 even at a high capacity of 6.0 mAh cm−2. The Coulombic efficiency also reaches a record 99% in 150 cycles. The Li3N–LiF/Li3PS4 SSE enables LiCoO2 cathodes to achieve 101.6 mAh g−1 for 50 cycles. The design principle opens a new opportunity to develop high‐energy all‐solid‐state Li metal batteries.
According to the proposed principles for the suppression of dendrite formation, a Li3N–LiF composite that is thermodynamically stable and has high interface energy against Li metal is designed as an interlayer for dendrite‐free all‐solid‐state batteries. A Li3N–LiF layer coating on a Li3PS4 solid‐state electrolyte achieves a record‐high critical current of >6 mA cm−2 even at a high capacity of 6.0 mAh cm−2.
We have investigated the influence of multimode fiber core (MMFC) diameters and lengths on the sensitivity of an SMS fiber based refractometer. We show that the MMFC diameter has significant ...influence on the refractive index (RI) sensitivity but the length does not. A refractometer with a lower MMFC diameter has a higher sensitivity. Experimental investigations achieved a maximum sensitivity of 1815 nm/ RIU (refractive index unit) for a refractive index range from 1.342 to 1.437 for a refractometer with a core diameter of 80 μm. The experimental results fit well with the numerical simulation results.
With the increasing demand for energy, layered lithium-rich manganese-based (Li-rich Mn-based) materials have attracted extensive attention because of their high capacity and high voltage. However, ...the Li-rich Mn-based materials suffer from a series of problems of oxygen release, transition metal (TM) migration, and structural transformation, which results in serious voltage and capacity decay. In this review, the lithium storage mechanism of the materials is systematically and critically summarized, in terms of the electrochemical performance problems such as large initial irreversible capacity, voltage decay, voltage hysteresis, inferior cycling performance, and electrolyte corrosion. We also summarize in detail the various modifications conducted in recent years, including component improvement, coating, doping, and surface treatment. Lastly, challenges and perspectives on future research directions for the development of high performance Li-rich Mn-based materials are also presented and discussed.
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•Analyzes the lithium storage mechanism at high and low voltage.•Summarizes the causes of damped electrochemical performance.•Presents the modification strategies to improve electrochemical performance.
Taking data of tourism attractions in international cultural tourism demonstration region in South Anhui in China, this study summarized the distribution characteristics of tourism attractions in ...region by applying GIS spatial analysis method such as nearest neighbor distance index and kernel density estimation method, and explored how natural conditions, urban infrastructure, social and economic development affect the distribution in order to better understand the distribution of regional tourism resources and serve the direction of tourism development. The study found that the tourist attractions in the demonstration area have a significant agglomeration on the whole, with Huangshan City as the main center and other districts and counties as the sub centers, presenting the trend of hierarchical development. In different kinds of tourism attractions, the distribution of natural tourism attractions and rural pastoral tourism attractions highly related to the topography. And the distribution of modern recreational tourism attractions and humanistic tourism attractions is closely related to hydrology. In terms of urban infrastructure, modern recreational tourism attractions hold the best accessibility with transportation. The core area of the demonstration region include Huangshan City, Chizhou city and Xuancheng city has better tourist industry development. Tourist attractions in other areas are relatively scarce, but the hold great potential for development in the future.
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