Dependence of Mixed Aerosol Light Scattering Extinction on Relative Humidity in Beijing and Hong Kong

The hygroscopic properties of mixed aerosol particles are crucial for the application of remote sensing products of aerosol optical parameters in the study of air quality and climate at multiple scales. In this study, the authors investigated aerosol optical properties as a function of relative humidity (RH) for two representative metropolises: Beijing and Hong Kong. In addition to the RH data, mass concentrations of PM 10 (particulate matter up to 10 μm in diameter) and aerosol scattering extinction coefficient (σ ext ) data were used. The relationship between the mass scattering extinction efficiency (MEE, defined as σ ext /PM 10 ) and RH can be expressed by regression functions as f = 1.52x + 0.29 (r2 = 0.77), f = 1.42x + 1.53 (r2 = 0.58), f = 1.19x + 0.65 (r2 = 0.59), and f = 1.58x + 1.30 (r2 = 0.61) for spring, summer, autumn, and winter, respectively, in Beijing. Here, f represents MEE, x represents 1/(1 RH), and the coefficients of determination are pre- sented in parentheses. Conversely, in Hong Kong, the corresponding functions are f = 1.98x 1.40 (r2 = 0.55), f = 1.32x 0.36 (r2 = 0.26), f = 1.87x 0.65 (r2 = 0.64), and f = 2.39x 1.47 (r2 = 0.72), respectively. The MEE values for Hong Kong at high RHs (RH > 70%) are higher than those for Beijing, except in summer; this suggests that aerosols in Hong Kong are more hygroscopic than those in Beijing for the other three seasons, but the aerosol hygroscopicity is similarly high in summer over both cities. This study describes the effects of moisture on aerosol scattering extinction coefficients and provides a potential method of studying atmospheric visibility and groundlevel air quality using some of the optical remote sensing products of satellites.

Multi-scale modeling of hemodynamics in the cardiovascular system

The human cardiovascular system is a closed- loop and complex vascular network with multi-scaled het- erogeneous hemodynamic phenomena. Here, we give a selective review of recent progress in macro-hemodynamic modeling, with a focus on geometrical multi-scale model- ing of the vascular network, micro-hemodynamic modeling of microcirculation, as well as blood cellular, subcellular, endothelial biomechanics, and their interaction with arter- ial vessel mechanics. We describe in detail the methodology of hemodynamic modeling and its potential applications in cardiovascular research and clinical practice. In addition, we present major topics for future study： recent progress of patient-specific hemodynamic modeling in clinical applica- tions, micro-hemodynamic modeling in capillaries and blood cells, and the importance and potential of the multi-scale hemodynarnic modeling.

D-type neuropeptide decorated AIEgen/RENP hybrid nanoprobes with light-driven ROS generation ability for NIR-Ⅱ fluorescence imaging-guided through-skull photodynamic therapy of gliomas

Glioma is one of the most common malignant tumors of the central nervous system,leading high mortality rates in human.Aggregation-induced emission(AIE)photosensitizers-based photodynamic therapy(PDT)has emerged as a promising therapeutic strategy for least-invasive treatment of glioma,which involves local irradiation of the tumor using an external near-infrared(NIR)laser.Unfortunately,most AIE photosensitizers suffered from poorly penetration of the visible light excitation,bad spatiotemporal resolution in deep tissues and low efficient blood-brain barrier(BBB)crossing ability,which greatly limited the clinical practice of AIE photosensitizers for especially deep-seated brain tumor treatment.In this work,we developed a multifunctional NIR-driven theranostic agent through hybrid of AIE photosensitizers TIND with rare-earth doping nanoparticles(RENPs)NaGdF4:Nd/Yb/Tm with up/down dual-mode conversion luminescence.The theranostic agent was further decorated with D-type neuropeptide DNPY for crossing BBB and targeting glioma.Under the 808-nm light irradiation,the down-conversion NIR-II luminescence could indicate the position glioma and the upconversion NIR-I luminescence could trigger the AIE photosensitizers producing reactive oxygen species to inhibit orthotopic glioma tumor growth in situ.These results demonstrate that the integration of Dtype neuropeptide,AIE photosensitizers and RENPs could be promising candidates for in vivo NIR-II fluorescence image-guided through-skull PDT treatments of brain tumors.

Electrochemical synthesis of β-hydroxy-, β-alkoxy-, and β-carbonyloxy sulfones by vicinal difunctionalization of olefins

An electrochemical vicinal heterodifunctionalization of olefins for the synthesis ofβ-oxysulfones is described.With suitable choice of the conditions,including current,electrodes,and electrolyte,this oxidation reaction proceeded efficiently in an undivided cell without the use of a stoichiometric chemical oxidant.In addition to the previously established synthesis ofβ-hydroxysulfones in the presence of water,minor modification of this protocol by using either external alcohol nucleophiles or internal carboxylic acid nucleophile also led to the synthesis ofβ-alkoxysulfones,andβ-sulfonyl lactones.

Promoting polysulfide conversions via cobalt single-atom catalyst for fast and durable lithium-sulfur batteries

Although promising strategies have been developed to resolve the critical drawbacks of lithium-sulfur(Li-S)batteries,the intractable issues including undesirable shuttling of polysulfides and sluggish redox reaction kinetics have still been unresolved thoroughly.Herein,a cobalt single-atom(CoSA)catalyst comprising of atomic Co distributed homogeneously within nitrogen(N)-doped porous carbon(Co-NPC)nanosphere is constructed and utilized as a separator coating in Li-S batteries.The Co-NPC exposes abundant active sites participating in sulfur redox reactions,and remarkable catalytic activity boosting the rapid polysulfide conversions.As a result,Li-S batteries with Co-NPC coating layer realize significantly enhanced specific capacity(1295 mAh·g^(-1)at 0.2 C),rate capability(753 mAh·g^(-1)at 3.0 C),and long-life cyclic stability(601 mAh·g^(-1)after 500 cycles at 1.0 C).Increasing the areal sulfur loading to 6.2 mg·cm^(-2),an extremely high areal capacity of 7.92 mAh·cm^(-2)is achieved.Further in situ X-ray diffraction,density functional theory calculations,and secondary ion mass spectrometry confirm the high catalytic capability of CoSA towards reversible polysulfide conversion.This study supplies new insights for adopting single-atom catalyst to upgrade the electrochemical performance of Li-S batteries.

Organocatalytic Enantioselective Synthesis of Chiral Diarylmethylamines from Racemic Alcohols

An organocatalytic approach for direct conversion of racemic diarylmethanols to valuable chiral diarylmethyiamines is described. Ditterent from the previously reported elegant ＂borrowing hydrogen＂ approach, the present process employs a distinct complementary formal SN 1 strategy. This approach enjoys excellent enantioselectivity, mild conditions, broad scope, and easy product derivatization. Mechanistically, control experiments also provided important insights into some notable features, such as substrate kinetic resolution and reversibility as well as the critical role of the ortho- hydroxy group in the substrate.

Review Article Electrocatalysts in lithium-sulfur batteries

Lithium-sulfur(Li-S)batteries with the merits of high theoretical capacity and high energy density have gained significant attention as the next-generation energy storage devices.Unfortunately,the main pressing issues of sluggish reaction kinetics and severe shuttling of polysulfides hampered their practical application.To overcome these obstacles,various strategies adopting high-efficient electrocatalysts have been explored to enable the rapid polysulfide conversions and thereby suppressing the polysulfide shuttling.This review first summarizes the recent progress on electrocatalysts involved in hosts,interlayers,and protective layers.Then,these electrocatalysts in Li-S batteries are analyzed by listing representative works,from the viewpoints of design concepts,engineering strategies,working principles,and electrochemical performance.Finally,the remaining issues/challenges and future perspectives facing electrocatalysts are given and discussed.This review may provide new guidance for the future construction of electrocatalysts and their further utilizations in high-performance Li-S batteries.