Cell-Penetrating Mitochondrion-Targeting Ligands for the Universal Delivery of Small Molecules,Proteins and Nanomaterials

Mitochondria are key organelles that perform vital cellular functions such as those related to cell survival and death. The targeted delivery of different types of cargos to mitochondria is a well-established strategy to study mitochondrial biology and diseases. Of the various existing mitochondrion-transporting vehicles, most suffer from poor cytosolic entry, low delivery efficiency, limited cargo types, and cumbersome preparation protocols, and none was known to be universally applicable for mitochondrial delivery of different types of cargos (small molecules, proteins, and nanomaterials). Herein, two new cell-penetrating, mitochondrion-targeting ligands (named Mito^Ligand) that are capable of effectively “tagging” small-molecule drugs, native proteins and nanomaterials are disclosed, as well as their corresponding chemoselective conjugation chemistry. Upon successful cellular delivery and rapid endosome escape, the released native cargos were found to be predominantly localized inside mitochondria. Finally, by successfully delivering doxorubicin, a well-known anticancer drug, to the mitochondria of HeLa cells, we showed that the released drug possessed potent cell cytotoxicity, disrupted the mitochondrial membrane potential and finally led to apoptosis. Our strategy thus paves the way for future mitochondrion-targeted therapy with a variety of biologically active agents.     

Ultrafast photo-induced turning of magnetization and its relaxation dynamics in GaMnAs

We report that,by linearly polarized pumping of different wavelengths,Kerr transients appear at zero magnetic field only in the case when GaMnAs samples are initialized at 3 K by first applying a 0.8 Tesla field and then returning to zero field.We find that,instead of magnetization precession,the near-band gap excitation induces a coherent out-of-plane turning of magnetization,which shows very long relaxation dynamics with no precession.When photon energy increases,the peak value of the Kerr transient incre...     

Bipolar copolymers comprised mesogen‐jacketed polymer containing oxadiazole units and PVK as host materials for electroluminescent devices

Nonconjugated bipolar transport polymers have been developed as host materials for electroluminescent devices by incorporating both electron‐transporting and hole‐transporting functionalities into copolymers. The random copolymer PCt‐nvk3‐7 containing mesogen‐jacketed segment of P‐Ct have been synthesized and characterized. The effect of mesogen‐jacketed segment content of these bipolar copolymers on device performance has been investigated. The results of polymer light‐emitting diodes (PLEDs) show that the jacketed content of copolymers has a significant effect on device performance: lowering charge transport and facilitating the hole‐electron recombination leads to much higher current efficiency. Applying these high triplet random copolymers as host, the maximum current efficiency of 0.70 cd/A and the maximum brightness of 1872.8 cd/m² was achieved for PCt‐nvk3‐7 with an orange‐emitting complex dopant. The results suggest that the bipolar copolymers PCt‐nvks can be good host polymers for electrophosphorescent devices. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7861–7867, 2008     

The synthesis and molecular recognization of the polyamine transporter of hydrazine-modified diamine conjugates

A series of four novel hydrazine-modified diamine conjugates （7a-b, 8a-b） were synthesized and evaluated for cytotoxicity against Melanoma B 16, α-difluoromethylornithine （DFMO）-treated B 16, spermidine （SPD）-treated B 16, Mouse leukemia L 1210 and Hela cell lines. Both the DFMO-B 16 and SPD-B 16 experiments indicated that conjugates 7a-b and 8a-b could recognize the polyamine transporter （PAT） and enter the cells in part or in whole via PAT, although they were not as efficient as the reference, 9- anthracenemethyl homospermidine （1）. 2007 Chao Jie Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.     

Study on structures and electron affinities of small potassium–silicon clusters Si n K (n = 2–8) and their anions with Gaussian-3 theory

The neutral Si _n K (n = 2–8) clusters and their anions have been systematically studied by means of the higher level of Gaussian-3 schemes. Equilibrium geometries and electron affinities have been calculated and are discussed for each considered size. For neutral Si _n K clusters, the ground state structure is found to be “attaching structure”, in which the K atom is bound to Si _n clusters. The most stable isomer for their anions, however, is found to be “substitutional structures”, which is derived from Si_(n+1) by replacing the Si atom with a K. The dissociation energies of K atom from the lowest energy structures of Si _n K have also been estimated to examine relative stabilities.     

New synthetic way to prepare 2-aryl-8-(piperidin-4-yl)-5,7-dimethoxy-4H-chromen-4-one as key intermediate for CDK inhibitor

As an important intermediate to study cyclin-dependent kinase(CDK)inhibitors,2-aryl-8-(piperidin-4-yl)-5,7-dimethoxy-4H- chromen-4-one derivatives were prepared usingβ-diketone route with low yield.In our study,chalcone route has been investigated and the result suggested that the benzaldehydes substituted with electron-donating group give much better yield thanβ-diketone route.This new method will be an efficient way to start further research on new anticancer flavonoids.     

On States of Total Weighted Occupation Times of a Class of Infinitely Divisible Superprocesses on a Bounded Domain

In this paper, general conditions of state classification for the total weighted occupation times of a class of infinitely divisible superprocesses on a bounded domain D in ℝ ^d are given. As an application, some sufficient and necessary conditions are found for the total weighted occupation times of some special superprocesses on D to be absolutely continuous or singular with respect to the Lebesgue measure on D. The research of Yan-Xia Ren is supported by NNSF of China (Grant No. 10471003) and Foundation for Authors Awarded Excellent Ph.D. Dissertation.     

VCSEL with reticular electrode and larger emitting aperture and its optoelectronic characteristics

The enlargement of the emitting aperture is usually one of the important methods of increasing vertical- cavity surface-emitting laser （VCSEL） optical output power. However, in a VCSEL with a larger aperture, the inhomogeneity in the injected current often causes inhomogeneous or even no emission. To solve this problem and to increase VCSEL output power, as well as to improve its thermal characteristics, we develop a new type of injected VCSEL with a larger aperture and a reticular electrode, where the conventional circular injection electrode of the P side is turned into a reticular one, and the heat sink is on the N side. The tests of the new VCSEL show an improvement in homogeneity in not only the injected current but also the emission intensity. The optical output power is also considerably increased, and the device optoelectronic performance is improved.     

高温超导中的磁弛豫

本文计算了涡旋玻璃态或集体蠕动模型和考虑反跳的热激活模型的驰豫率，并与实验数据进行了比较，发现前者在较低温度与实践符合较好，而后者在接近Ｔｃ的较高的温度与实验符合较好。本文还对此进行了讨论。