Exosome-Coated Zeolitic Imidazolate Framework Nanoparticles for Intracellular Detection of ATP

The intracellular delivery of metal-organic frameworks(MOFs)encapsulated with functional biomolecules represents a promising av-enue in the field of biomedicine...     

Investigations of the optical and EPR spectra for VO2+ in LiKSO4 crystals

The optical spectra and EPR spectra (characterized by the spin-Hamiltonian parameters g(//), g(perpendicular), A(//) and A(perpendicular)) for the molecular ion VO2+ in LiKSO4 crystals are calculated from two microscopic theory methods, one of which is the complete diagonalization (of energy matrix) method (CDM) and the other is the perturbation theory method (PTM). The calculated three optical absorption bands and four spin-Hamiltonian parameters from the two methods are not only close to each other, but also in reasonable agreement with the experimental values. It appears that both theoretical methods are effective in the explanation of optical and EPR spectra for 3d1 ions in crystals. The negative signs of hyperfine structure constants A(//) and A(perpendicular) for VO2+ in LiKSO4 crystals are also suggested from the calculations.     

Shape-specific detection based on fluorescence resonance energy transfer using a flexible water-soluble conjugated polymer

We present the detection of the shape-specific conformation of DNA based on the fluorescence resonance energy transfer (FRET) by using a novel flexible water-soluble cationic conjugated polymer (CCP). The flexible backbone of CCP has more conformational freedom with the potential to be responsive to analyte shape by electrostatic interaction between flexible CCP and negatively charged DNA. The analyte shape dependent recognition is accomplished by structural changes that compressed or extended the flexible CCP. The morphology-dependent spectral properties of the novel flexible polymer related to the analyte shapes are investigated in detail, where two types of chromophores, referred to as "isolated" segment and "packed" segment aggregates, within the flexible polymer are identified by means of ensemble and single molecule measurements upon binding with different geometric DNA. The change in fluorescence intensity upon binding with shape-specific DNA without obvious color shifts makes this novel flexible polymer a suitable CCP donor for FRET measurements. The results provide insights for understanding the spectral properties of flexible water-soluble CCP and CCP/DNA interaction related to the geometry of target analyte.     

一种Q波段多孔耦合型定向耦合器

论述了一种宽带多孔耦合型定向耦合器,工作频段中心频率为40 GHz,相对带宽50%,拟用于射电望远镜Q波段接收机系统。该定向耦合器为一款结构紧凑的器件,采用对称的等间距多孔耦合形式,将主通道圆波导TE11模式信号耦合到耦合通道的矩形波导中,实现了小于-20 dB 耦合特性。为了对设计进行验证,对该定向耦合器进行了加工和测试。测试结果表明,在30~50 GHz 工作频段内,主通道反射系数小于-24.2 dB,且全频段内的端口耦合度保持在-20~-21 dB 之间。仿真与测试结果具有较高的吻合度,进一步证实了该设计可用于射电天文望远镜的Q波段接收机系统。     

A beta-keto ester as a novel, efficient, and versatile ligand for copper(I)-catalyzed C-N, C-O, and C-S coupling reactions

Employing ethyl 2-oxocyclohexanecarboxylate as a novel, efficient, and versatile ligand, the copper-catalyzed coupling reactions of various N/O/S nucleophilic reagents with aryl halides could be successfully carried out under mild conditions. A variety of products including N-arylamides, N-arylimidazoles, aryl ethers, and aryl thioethers were synthesized in good to excellent yields.     

Enhanced luminescence of Eu(3+) by Y(3+) in ternary complexes Eu(X)Y(1-X)(TTA)3Dipy

Rare-earth ternary complexes Eu(X)Y(1-X)(TTA)3Dipy {X=0, 0.1, 0.25, 0.5, 0.75, 0.9, 1.0, using thenoyltrifluoroacetone (TTA) as ligand and 2,2'-dipyridyl (Dipy) as synergic agent} were synthesized. Characterization with X-ray diffraction (XRD), IR and elemental analysis had also been carried out. The photophysical properties of these complexes were studied in detail with ultraviolet absorption spectra and fluorescent spectra. It is found that the enhanced luminescence of Eu(3+) ions by Y(3+) ions occurs in ternary complexes. And we monitored the spectra of Eu(X)Y(1-X)(TTA)3Dipy (PVK:Eu/BCP/AlQ/Al) at the different rate (rpm). The results showed that the Y(3+) ion acts as an energy transfer bridge that helps energy transfer from PVK to Eu(3+).     

PREPARATION AND CHARACTERIZATION OF AFFINITY POLYMER BASIC MICROSPHERES BY SOAP-FREE EMULSION POLYMERIZATION

Poly(styrene-co-glycidyl methacrylate) latex microspheres with uniform size and high-density epoxy groups on the surface were prepared by soap-free emulsion polymerization with batch wise operation mode in the presence of 2.2′- azobis(2-methylpropionamidine) dihydrochloride as an initiator.The kinetics of soap-free emulsion polymerization and the effects of polymerization factors were examined.In addition,the optimum polymerization conditions of poly(styrene-co- glycidyl methacrylate) latex microspheres ...     

Coptidis rhizoma extract protects against cytokine-induced death of pancreatic beta-cells through suppression of NF-kappaB activation

We demonstrated previously that Coptidis rhizoma extract (CRE) prevented S-nitroso-N-acetylpenicillamine-induced apoptotic cell death via the inhibition of mitochondrial membrane potential disruption and cytochrome c release in RINm5F (RIN) rat insulinoma cells. In this study, the preventive effects of CRE against cytokine-induced beta-cell death was assessed. Cytokines generated by immune cells infiltrating pancreatic islets are crucial mediators of beta-cell destruction in insulin-dependent diabetes mellitus. The treatment of RIN cells with IL-1beta and IFN-gamma resulted in a reduction of cell viability. CRE completely protected IL-1beta and IFN-gamma-mediated cell death in a concentration-dependent manner. Incubation with CRE induced a significant suppression of IL-1beta and IFN-gamma-induced nitric oxide (NO) production, a finding which correlated well with reduced levels of the iNOS mRNA and protein. The molecular mechanism by which CRE inhibited iNOS gene expression appeared to involve the inhibition of NF-kappaB activation. The IL-1beta and IFN-gamma-stimulated RIN cells showed increases in NF-kappaB binding activity and p65 subunit levels in nucleus, and IkappaB alpha degradation in cytosol compared to unstimulated cells. Furthermore, the protective effects of CRE were verified via the observation of reduced NO generation and iNOS expression, and normal insulin-secretion responses to glucose in IL-1beta and IFN-gamma-treated islets.