Low-Temperature Growing Anatase TiO2/SnO2 Multi-dimensional Heterojunctions at MXene Conductive Network for High-Efficient Perovskite Solar Cells

A multi-dimensional conductive heterojunction structure,composited by TiO2,SnO2,and Ti3C2TX MXene,is facilely designed and applied as electron transport layer in efficient and stable planar perovskite solar cells.Based on an oxygen vacancy scramble effect,the zero-dimensional anatase TiO2 quantum dots,surrounding on two-dimensional conductive Ti3C2TX sheets,are in situ rooted on three-dimensional SnO2 nanoparticles,constructing nanoscale TiO2/SnO2 heterojunctions.The fabrication is implemented in a controlled lowtemperature anneal method in air and then in N2 atmospheres.With the optimal MXene content,the optical property,the crystallinity of perovskite layer,and internal interfaces are all facilitated,contributing more amount of carrier with effective and rapid transferring in device.The champion power conversion efficiency of resultant perovskite solar cells achieves 19.14%,yet that of counterpart is just 16.83%.In addition,it can also maintain almost 85%of its initial performance for more than 45 days in 30–40%humidity air;comparatively,the counterpart declines to just below 75%of its initial performance.

Methyl 3,4-dihydroxybenzoate promotes neurite outgrowth of cortical neurons cultured in vitro

Cerebral cortical neurons from neonatal rats were cultured in the presence of methyl 3,4-dihydroxybenzoate （MDHB; 2, 4, and 8 IJM）. Results showed that MDHB significantly promoted neurite outgrowth and microtubule-associated protein 2 mRNA expression, and increased neuronal survival in a dose-dependent manner. Moreover, MDHB induced brain-derived neurotrophic factor expression. These findings suggest that MDHB has a neurotrophic effect, which may be due to its ability to increase brain-derived neurotrophic factor expression.

Development of LAG-3/FGL1 blocking peptide and combination with radiotherapy for cancer immunotherapy

Aside from antibodies,peptides show great potential as immune checkpoint inhibitors(ICIs)due to several advantages,such as better tumor penetration and lower cost.Lymphocyte-activation gene 3(LAG-3)is an immune checkpoint which can induce T cell dysfunction through interaction with its soluble ligand fibrinogen like protein-1(FGL1).Here,we found that LAG-3 expression was higher than programmed cell death protein 1(PD-1)in multiple human cancers by TCGA databases,and successfully identified a LAG-3 binding peptide LFP-6 by phage display bio-panning,which specifically blocks the interaction of LAG-3/FGL1 but not LAG-3/MHC-II.Subsequently,D-amino acids were introduced to substitute the N-and C-terminus of LFP-6 to obtain the proteolysis-resistant peptide LFP-D1,which restores T cell function in vitro and inhibits tumor growth in vivo.Further,a bispecific peptide LFOP targeting both PD-1/PD-L1 and LAG-3/FGL1 was designed by conjugating LFP-D1 with PD-1/PD-L1blocking peptide OPBP-1(8-12),which activates T cell with enhanced proliferation and IFN-γ production.More importantly,LFOP combined with radiotherapy significantly improve the T cell infiltration in tumor and elevate systemic antitumor immune response.In conclusion,we developed a novel peptide blocking LAG-3/FGL1 which can restore T cell function,and the bispecific peptide synergizes with radiotherapy to further enhance the antitumor immune response.

Hemin blocks TIGIT/PVR interaction and induces ferroptosis to elicit synergistic effects of cancer immunotherapy

The immune checkpoint TIGIT/PVR blockade exhibits significant antitumor effects through activation of NK and CD8^(+)T cell-mediated cytotoxicity.Immune checkpoint blockade(ICB)could induce tumor ferroptosis through IFN-γreleased by immune cells,indicating the synergetic effects of ICB with ferroptosis in inhibiting tumor growth.However,the development of TIGIT/PVR inhibitors with ferroptosis-inducing effects has not been explored yet.In this study,the small molecule Hemin that could bind withTIGIT to block TIGIT/PVR interaction was screened by virtual molecular docking and cell-based blocking assay.Hemin could effectively restore the IL-2 secretion from Jurkat-hTIGIT cells.Hemin reinvigorated the function of CD8^(+)T cells to secrete IFN-γand the elevated IFN-γcould synergize with Hemin to induce ferroptosis in tumor cells.Hemin inhibited tumor growth by boosting CD8^(+)T cell immune response and inducing ferroptosis in CT26 tumor model.More importantly,Hemin in combination with PD-1/PD-L1 blockade exhibited more effective antitumor efficacy in anti-PD-1 resistant B16 tumor model.In summary,our finding indicated that Hemin blocked TIGIT/PVR interaction and induced tumor cell ferroptosis,which provided a new therapeutic strategy to combine immunotherapy and ferroptosis for cancer treatment.

Identification and optimization of peptide inhibitors to block VISTA/PSGL-1 interaction for cancer immunotherapy

Developing new therapeutic agents for cancer immunotherapy is highly demanding due to the low response ratio of PD-1/PD-L1 blockade in cancer patients.Here,we discovered that the novel immune checkpoint VISTA is highly expressed on a variety of tumor-infiltrating immune cells,especially myeloid derived suppressor cells(MDSCs)and CD8^(+)T cells.Then,peptide C1 with binding affinity to VISTA was developed by phage displayed bio-panning technique,and its mutant peptide VS3 was obtained by molecular docking based mutation.Peptide VS3 could bind VISTA with high affinity and block its interaction with ligand PSGL-1 under acidic condition,and elicit anti-tumor activity in vivo.The peptide DVS3-Pal was further designed by D-amino acid substitution and fatty acid modification,which exhibited strong proteolytic stability and significant anti-tumor activity through enhancing CD8^(+)T cell function and decreasing MDSCs infiltration.This is the first study to develop peptides to block VISTA/PSGL-1 interaction,which could act as promising candidates for cancer immunotherapy.

Rare earth recovery from fluoride molten-salt electrolytic slag by sodium carbonate roasting-hydrochloric acid leaching

Fluorinated rare earth molten-salt electrolytic slag contains a considerable amount of rare earth elements,as well as a variety of heavy metals and fluorides that cause environmental pollution.Therefore,it is of great importance to fully utilise this resource.In this study,the transformation mechanism of fluorinated rare earth molten-salt electrolytic slag roasted with sodium carbonate,and the regulation mechanism of rare earth leaching under different roasting conditions were investigated with the help of thermodynamic calculation of the reactions and kinetic analysis.The thermodynamic and differential thermal thermogravimetric(DTA-TG)analysis shows that the transformation of rare earth fluoride to rare earth oxide is promoted at elevated temperature.Furthermore,the leaching experimental results show that increasing the temperature,time,hydrochloric acid concentration,and liquid-solid ratio can effectively promote the recovery of rare earths.The optimum experimental conditions are a roasting temperature of 700℃,roasting time of 2 h,and sodium carbonate to molten salt electrolytic slag mass ratio of 0.6,followed by leaching at 80℃with a liquid-solid ratio of 10:1 by adding 3 moI/L hydrochlo ric acid with stirring for 2 h.Under these conditions,the rare earths in the molten salt electrolytic slag are biologically transformed at a lower temperature and the leaching efficiency of rare earths exceeds 98%.

利用AlGaN耦合作用调控WS_(2)层内和层间谷激子

二维材料中的激子跃迁和能谷极化过程具有丰富的能谷物理特性,因此具有极大的研究价值.本文发现,单层和双层WS_(2)中激子和能谷特性可以通过耦合不同掺杂浓度的AlGaN进行有效调控.当WS_(2)和n型AlGaN耦合时,会出现显著的激子能量红移.值得一提的是,来自AlGaN的层间电荷转移作用会促使双层WS_(2)形成II型能带,进而产生层间激子跃迁.层内激子峰和层间激子峰的能量和强度还可以通过双层WS_(2)中的转角进行调控.在13 K条件下,通过耦合n型AlGaN,单层WS_(2)的谷极化率高达82.2%.这是由于AlGaN的电子-声子相互作用会带来更高的激子衰减速率,且掺杂导致的载流子屏蔽效应会减少层间谷散射.层间激子的谷极化率明显高于层内激子,这是由于在层间激子中电子-空穴相互作用较弱,导致层间谷散射受到抑制.本文提出了一种简便有效的方法来调控二维材料的激子特性,在单层WS_(2)中实现了极高的谷极化,并在双层WS_(2)中诱导出层间激子.这些发现将激发谷激子物理学的创新探索,并推动新兴的谷电子器件的应用研究.

Diffusion occupation time before exiting

Using the approach of D. Landriault et al. and B. Li and X. Zhou, for a one-dimensional time-homogeneous diffusion process X and constants c 〈 a 〈 b 〈 d, we find expressions of double Laplace transforms of the form Ex[e--θTd--λ∫o Td1a 〈Xs〈b ds; Td 〈 Tc], where Tx denotes the first passage time of level x. As applications, we find explicit Laplace transforms of the corresponding occupation time and occupation density for the Brownian motion with two-valued drift and that of occupation time for the skew Ornstein- Uhlenbeck process, respectively. Some known results are also recovered.

Random packing of tetrahedral particles using the polyhedral discrete element method

The random packing of tetrahedral particles is studied by applying the discrete element method （DEM）, which simulates the effects of friction, height ratio, and eccentricity. The model predictions are ana- lyzed in terms of packing density and coordination number （CN）. It is demonstrated that friction has the maximal effect on packing density and mean CN among the three parameters. The packing den- sity of the regular tetrahedron is 0.71 when extrapolated to a zero friction effect. The shape effects of height ratio and eccentricity show that the regular tetrahedron has the highest packing density in the family of tetrahedra, which is consistent with what has been reported in the literature. Compared with geometry-based packing algorithms, the DEM packing density is much lower. This demonstrates that the inter-particle mechanical forces have a considerable effect on packing. The DEM results agree with the published experimental results, indicating that the polyhedral DEM model is suitable for simulating the random packing of tetrahedral particles.

DEM investigation of angle of repose for super-ellipsoidal particles

We explore the effect of particle shape on the angle of repose (AoR) in granular packing using a three-dimensional discrete element method.Non-spherical particles were modeled using super-ellipsoids characterized by aspect ratio and blockiness.The relationship between AoR and particle shape was examined,followed by a series of analyses on the origin of AoR from a microscopic perspective.Results show that,with blockiness deviating from unity,AoR has an approximate "M" shape that exhibits a strong to weak trend with aspect ratio,matching results of previous reports.Another finding suggests a parabolic relationship between normalized AoR and normalized coordination number,AoR increases with anisotropy related more with the anisotropy of particle orientation than with the anisotropy of contact normal.Particle shape is more likely to affect AoR by affecting the tangential force than the normal contact force.An analysis based on traction indicates that dips in stress associated with the tangential force (compared with the normal force) and non-spherical particles (compared with spheres) are more significant.For various particle shapes,AoR is positively correlated with friction mobilization but is negatively correlated with friction mobilization for various coefficient of friction.

An occupation time related potential measure for diffusion processes

In this paper, for homogeneous diffusion processes, the approach of Y. Li and X. Zhou [Statist. Probab. Lett., 2014, 94： 48-55] is adopted to find expressions of potential measures that are discounted by their joint occupation times over semi-infinite intervals （-∞, a） and （a, ∞）. The results are expressed in terms of solutions to the differential equations associated with the diffusions generator. Applying these results, we obtain more explicit expressions for Brownian motion with drift, skew Brownian motion, and Brownian motion with two-valued drift, respectively.

Neurotrophic effects of 7,8-dihydroxycoumarin in primary cultured rat cortical neurons

Objective Neuronal loss in the central nervous system is central to the occurrence of neurodegenerative diseases. Pharmaceutical companies have devoted much effort to developing new drugs against such diseases, since there are currently no effective drugs for neurodegenerative disease treatment. Promoting the capacity for nerve regeneration is an ideal treatment target. The present study aimed to investigate the neurotrophic effects of 7,8-dihydroxycoumarin （DHC） or daphnetin in primary cultured rat cortical neurons. Methods Cortical neurons were identified by microtubule-associated protein 2 （MAP2） immunostaining. Morphological observation was used to measure the average length of neurite outgrowth. MTT and lactate dehydrogenase assays were used to assess neuronal survival. The mRNA expression of MAP2 and brain-derived neurotrophic factor （BDNF） was measured by RT-PCR. Results MAP2 immunostaining showed that most of the cultured cells were neurons. Compared with the vehicle control group, DHC promoted neurite outgrowth and prolonged neuronal survival time at concentrations ranging from 2 to 8 μmol/L. Expression of both BDNF mRNA and MAP2 mRNAwas increased in the groups treated with 2, 4 and 8 μmol/L DHC. Conclusion DHC significantly increases neurite outgrowth and promotes neuronal survival in primary cultured rat cortical neurons. The neurotrophic effects of DHC are probably associated with increased BDNF expression.

一类连续状态非线性分枝过程的离散逼近

本文考虑一类连续状态非线性分枝过程.直观上,这是一类带竞争且分枝速率与状态相依的连续状态分枝过程.我们可以用由Brown运动和Poisson随机测度驱动的随机微分方程的解来构造该类过程.本文的主要结果是构造一列离散状态Markov链,并在较弱的条件下,通过胎紧性结论以及构造无穷维乘积空间上的收敛序列的方法证明其在轨道空间上弱收敛于上述连续状态的非线性分枝过程.

A Wiener-Hopf factorization related potential measure for spectrally negative Lévy process

For spectrally negative Lévy process (SNLP), we find an expression, in terms of scale functions, for a potential measure involving the maximum and the last time of reaching the maximum up to a draw-down time. As applications, we obtain a potential measure for the reflected SNLP and recover a joint Laplace transform for the Wiener-Hopf factorization for SNLP.

Direct synthesis of moirésuperlattice through chemical vapor deposition growth of monolayer WS_(2)on plasma-treated HOPG

Vertical van der Waals(vdW)heterostructures composed of two-dimensional(2D)layered materials have recently attracted substantial interests due to their unique properties.However,the direct synthesis of moirésuperlattice remains a great challenge due to the difficulties in heterogeneous nucleation on smooth vdW surfaces.Here,we report a controllable chemical vapor deposition growth of complete monolayer WS_(2)on highly ordered pyrolytic graphite(HOPG)substrates through the plasma pretreatment.The results show that the morphologies of the grown WS_(2)have a strong dependence on the plasma parameters,including gas composition,source power,and treatment time.It is found that the surface C–C bonds are broken in the plasma pretreated HOPG,and the formed small clusters can act as the nucleation sites for the subsequent growth of WS_(2).Moreover,the height of clusters dominates the growth mode of WS_(2)islands.A transition from a 2D mode to three-dimensional(3D)growth mode occurs when the height is higher than the interlayer spacing of the heterostructure.Besides,diverse moirésuperlattices with different twist angles for WS_(2)/HOPG heterostructures are observed,and the formation mechanism is further analyzed by firstprinciples calculations.

Branching particle systems in spectrally one-sided Levy processes

We investigate the branching structure coded by the excursion above zero of a spectrally positive Levy process. The main idea is to identify the level of the Levy excursion as the time and count the number of jumps upcrossing the level. By regarding the size of a jump as the birth site of a particle, we construct a branching particle system in which the particles undergo nonlocal branchings and deterministic spatial motions to the left on the positive half line. A particle is removed from the system as soon as it reaches the origin. Then a measure-valued Borel right Markov process can be defined as the counting measures of the particle system. Its total mass evolves according to a Crump- Mode-Jagers （CMJ） branching process and its support represents the residual life times of those existing particles. A similar result for spectrally negative Levy process is established by a time reversal approach. Properties of the measure- valued processes can be studied via the excursions for the corresponding Levy processes.