Biofouling-resistance expanded poly(tetrafluoroethylene) membrane with a hydrogel-like layer of surface-immobilized poly(ethylene glycol) methacrylate for human plasma protein repulsions

In general, it is a challenge to control the highly polar material grafting from the chemically inert Teflon-based membrane surface. This work describes the surface modification and characterization of expanded poly(tetrafluoroethylene) (ePTFE) membranes grafted with poly(ethylene glycol) methacrylate (PEGMA) macromonomer via surface-activated plasma treatment and thermally induced graft copolymerization. The chemical composition and microstructure of the surface-modified ePTFE membranes were characterized by Fourier transform infrared spectroscopy (FT-IR), contact angle, and bio-atomic force microscopy (bio-AFM) measurements. Biofouling property of the modified membranes was evaluated by the measurements of the plasma protein (γ-globulin, fibrinogen, or albumin) adsorption determined using an enzyme-linked immunosorbent assay (ELISA). In general, the hydrophilicity of the surface of ePTFE membranes increases with increasing the grafting degree of the copolymerized PEGMA. The highly hydrated PEGMA chain on the resulting ePTFE membranes was found to form a surface hydrogel-like layer with regulated coverage in aqueous state, which can be controlled by the content of PEGMA macromonomer in the reaction solution. The relative protein adsorption was effectively reduced with increasing capacity of the hydration for the PEGMA chain grafted on the ePTFE membrane surface. From both results of protein adsorption and platelet adhesion test in vitro, it is concluded that the PEGMA-grafted hydrophilic ePTFE membranes could provide good biofouling resistance to substantially reduce plasma protein and blood platelet fouling on the membrane surface in human body temperature.     

Synthesis of 2‐[4‐(Imidazolin‐2‐Ylideneamino)Benzyl]‐Indan‐1‐Ones as Novel Potent Prostacyclin Antagonists

Prostacyclin is involved in many pathological conditions, such as sensitization of inflammation induced pain and isovolumetic distention. Therefore, antagonism of prostacyclin action may be useful in the alleviation of these conditions. In this study, novel potent prostacyclin antagonists, 2‐[4‐(imidazolin‐2‐ylideneamino)benzyl]‐indan‐1‐ones were synthesized from their respective substituted indanones in three steps. The construction of the amino‐imidazole moiety of these derivatives is achieved by using in situ generation of chloro‐imidazole and reaction with their respective anilines. Thus, these N‐substituted 2‐imidazolines can be prepared safely and efficiently. Moreover, these compounds show potent prostacyclin antagonistic activity by inhibition of prostacyclin agonist induced ERK_1/2 phosphorylation in human erythroleukemia cells. Moreover, we observed an increase in activity with the increase in electro‐donating property of the substitution on the indanone aromatic ring. Prostacyclin antagonists with increased potency may be designed based on these findings. These compounds may also be invaluable tools for the study of the physiological functions of prostacyclin.     

Fe_3O_4@SiO_2@TiO_2复合纳米结构的尺寸与磁性调控

采用共沉淀法和溶剂热法制备了不同尺寸的Fe_3O_4纳米粒子,通过Stber法和溶胶-凝胶法在Fe_3O_4磁核上包覆SiO_2和Ti O2壳层获得不同尺寸的Fe_3O_4@SiO_2@Ti O2复合纳米结构.采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和振动样品磁强计(VSM)等对其结构、形貌和磁性进行了研究.结果表明,大尺寸复合纳米粒子包覆均匀,分散性好,饱和磁化强度较大,有利于TiO_2光催化剂的磁回收与再利用.     

Discrimination of Fluoroamphetamine Regioisomers by Raman Spectroscopy

The ability of a portable Raman spectrometer to perform on‐site and real time discrimination of fluoroamphetamine regioisomers demonstrated in this study. It suggests the presence and the position shifts of Star of David ring breathing vibration around 1000 cm^?1 and C? F stretching vibrations are assigned at 1232 cm^?1 (2‐FA), 1241 cm^?1 (3‐FA) and 1217 cm^?1 (4‐FA) are good indicators to differentiate ortho‐, meta‐ and para‐FAs, whereas the C? F vibrational shifts can help to confirm the determination.     

Two-dimensional infrared investigation of N-acetyl tryptophan methyl amide in solution

The linear infrared and two-dimensional infrared (2D IR) spectra in the amide-I region of N-acetyl tryptophan methyl amide (NATMA) in solvents of varying polarity are reported. The two amide-I transitions have been assigned unambiguously by using 13C isotopic substitution of the carbonyl group. The amide unit at the amino end shows a lower transition frequency in CH2Cl2 and methanol, while the acetyl end has a lower transition frequency in D2O. Multiple conformers exist in CH2Cl2 and methanol, but only one conformer is evident in D2O. The 2D IR cross peaks from the intermode coupling yield off-diagonal anharmonicities 2.5 +/- 0.5, 3.25 +/- 0.5, and 3.0 +/- 0.5 cm(-1) in CH2Cl2, methanol, and D2O, respectively, which by simple matrix diagonalization yield the coupling constants 8.0 +/- 0.5, 8.0 +/- 1.0, and 5.5 +/- 1.0 cm(-1). The major conformer in CH2Cl2 corresponds to a C7 structure, in agreement with that found in the gas phase [Dian, B. C.; Longarte, A.; Mercier, S.; Evans, D. A.; Wales, D. J.; Zwier, T. S. J. Chem. Phys. 2002, 117, 10688-10702] with intramolecular hydrogen bonding between the acetyl end C=O and the amino end N-H. The backbone dihedral angles (phi, psi) are determined to be in the ranges of (-55 +/- 5 degrees , 30 +/- 5 degrees ), (120 +/- 10 degrees , -20 +/- 10 degrees ), and (+/-160 +/- 10 degrees , +/-75 +/- 10 degrees ) in CH2Cl2, methanol, and D2O, respectively.     

A class of small molecules that inhibit TNFalpha-induced survival and death pathways via prevention of interactions between TNFalphaRI, TRADD, and RIP1

Small-molecule library screening to find compounds that inhibit TNFalpha-induced, but not interleukin 1beta (IL-1beta)-induced, intercellular adhesion molecule 1 (ICAM-1) expression in lung epithelial cells identified a class of triazoloquinoxalines. These compounds not only inhibited the TNFalpha-induced nuclear factor kappaB (NFkappaB) survival pathway but also blocked death-pathway activation. Such dual activity makes them unique against other known NFkappaB-pathway inhibitors that inhibit only a subset of TNFalpha signals leading to increased TNFalpha-induced cytotoxicity. Interestingly, these compounds inhibited association of TNFalpha receptor (TNFalphaR) I with TNFalphaR-associated death domain protein (TRADD) and receptor interacting protein 1 (RIP1), the initial intracellular signaling event following TNFalpha stimulation. Further study showed that they blocked ligand-dependent internalization of the TNFalpha-TNFalphaR complex, thereby inhibiting most of the TNFalpha-induced cellular responses. Thus, compounds with a triazoloquinoxaline scaffold could be a valuable tool to investigate small molecule-based anti-TNFalpha therapies.     

Analysis of Millimeter Wave Scattering by an Electrically Large Metallic Grating Using Wavelet-Based Algebraic Multigrid Preconditioned CG Method

An effective wavelet based multigrid preconditioned conjugate gradient method is developed to solve electromagnetic large matrix problem for millimeter wave scattering application. By using wavelet transformation we restrict the large matrix equation to a relative smaller matrix and which can be solved rapidly. The solution is prolonged as the new improvement for the conjugate gradient (CG) method. Numerical results show that our developed wavelet based multigrid preconditioned CG method can reach large improvement of computational complexity. Due to the automaticity of wavelet transformation, this method is potential to be a block box solver without physical background.     

Scattering Properties of Cylindrical Ferrite Posts and Their Applications

The scattering field of a ferrite post and a cylindrical ferrite post containing conducting post illuminated by a plane wave is analyzed. The special interest is the scattering property of the ferrite posts, which is resonating at certain modes such as TM₁₁ mode. We hope to know the speciality it shows and find its applications. It is found that the scattering field pattern of a resonating ferrite post is similar to the rotation of the scattering field pattern of a dielectric cylindrical post, which has the same dimension as ferrite. The scattering properties of the ferrite may give us some inspirations to explore its applications in microwave components. This property is utilized to explain the mechanism of the operation of the circulators. It also may be used in microstrip patch antenna, coupler and filter to control their properties. Other applications may be possible too. Some calculation results are presented.     

Investigation of Waveguide Y-Junction Circulator with a Triangular Ferrite Post

An H-plane waveguide Y-junction circulator with a triangular ferrite post is investigated by a modified analysis of jointly resonance theory and simple field theory. Good agreement between the theoretical obtained performances and experimental results is observed. The circulator exhibits a very low insertion loss and a wide bandwidth.     

Nanoscale C‐Rich SixC1−x Bus/Ring Waveguide Based Cross‐Wavelength Data Converter

The carbon‐rich silicon carbide (C‐rich Si_xC_1?x) micro‐ring channel waveguide with asymmetric core aspect is demonstrated for all‐optical cross‐wavelength pulsed return‐to‐zero on‐off keying (PRZ‐OOK) data conversion. Enhanced nonlinear optical Kerr switching enables 12‐Gbit per second data processing with optimized modulation depth. The inverse tapered waveguide at end‐face further enlarges the edge‐coupling efficiency, and the asymmetric channel waveguide distinguishes the polarization modes. To prevent data shape distortion, the bus/ring gap spacing is adjusted to control the quality factor (Q‐factor) of the micro‐ring. Designing the waveguide cross section at 500 × 350 nm² provides the C‐rich Si_xC_1?x channel waveguide to induce strong transverse electric mode (TE‐mode) confinement with a large Kerr nonlinearity of 2.44 × 10^?12 cm² W^?1. Owing to the trade‐off between the Q‐factor and the on/off extinction ratio, the optimized bus/ring gap spacing of 1400 nm is selected to provide a coupling ratio at 5–6% for compromising the modulation depth and the switching throughput. Such a C‐rich Si_xC_1?x micro‐ring with asymmetric channel waveguide greatly enhances the cross‐wavelength data conversion efficiency to favor its on‐chip all‐optical data processing applications for future optoelectronic interconnect circuits.