排序方式: 共有13条查询结果,搜索用时 15 毫秒
1.
Planar supported lipid bilayers (PSLBs) have been widely studied as biomembrane models and biosensor scaffolds. For technological applications, a major limitation of PSLBs composed of fluid lipids is that the bilayer structure is readily disrupted when exposed to chemical, mechanical, and thermal stresses. A number of asymmetric supported bilayer structures, such as the hybrid bilayer membrane (HBM) and the tethered bilayer lipid membrane (tBLM), have been created as an alternative to symmetric PSLBs. In both HBMs and tBLMs, the inner monolayer is covalently attached to the substrate while the outer monolayer is typically composed of a fluid lipid. Here we address if cross-linking polymerization of the lipids in the outer monolayer of an asymmetric supported bilayer can achieve the high degree of stability observed previously for symmetric PSLBs in which both monolayers are cross-linked [E.E. Ross, L.J. Rozanski, T. Spratt, S.C. Liu, D.F. O'Brien, S.S. Saavedra, Langmuir 19 (2003) 1752]. To explore this issue, HBMs composed of an outer monolayer of a cross-linkable lipid, bis-sorbylphosphatidylcholine (bis-SorbPC), and an inner SAM were prepared and characterized. Several experimental conditions were varied: vesicle fusion time, polymerization method, and polymerization time and temperature. Under most conditions, bis-SorbPC cross-linking stabilized the HBM such that its bilayer structure was largely preserved after drying; however these films invariably contained sub-micron scale defects that exposed the hydrophobic core of the HBM. The defects appear to be caused by desorption of low molecular weight oligomers when the film is removed from water, rinsed, and dried. In contrast, poly(bis-SorbPC) PSLBs prepared under similar conditions by Ross et al. were nearly defect free. This comparison shows that formation of a cross-linked network in the outer leaflet of an asymmetric supported bilayer is insufficient to prevent lipid desorption; inter-leaflet covalent linking appears to be necessary to create supported poly(lipid) assemblies that are impervious to repeated drying and rehydration. The difference in stability is attributed to inter-leaflet cross-linking between monolayers which can form in symmetric bis-SorbPC PSLBs. 相似文献
2.
本文利用KDV方程所对应的线性方程解所具有的光滑效应及压缩映像原理,得到了Hirota-Satsuma系统初值问题的局部和整体适定性结果. 相似文献
3.
The vibronic vapour phase photoacoustic spectrum of Br2 in the wavelength region 505–541 nm (19796–18480 cm−1) has been recorded using microphone as well as pump-probe method. Discrete vibronic bands superimposed on a monotonically
increasing continuum background towards the dissociation limit results from the overlapping B
3Π
0u
/+
← X
1Σ
g
/+
and 1Π1u
← X
1Σ
g
/+
electronic transitions. Vibronic bands originating from υ″=0 have been used to estimate the relative rate of non-radiative relaxation as a function of the excited state B
3Π0u
vibrational quantum number υ′. A comparison with the optical absorption spectroscopy of Br2 leads to the identification of three broad spectral regions between 505 and 541 nm (19796 and 18480 cm−1) on the basis of different non-radiative relaxation processes. 相似文献
4.
Slides for ultra thin-layer chromatography (UTLC) were made by coating nonporous silica particles, chemically modified with polyacrylamide, as 15 μm films on glass or silicon. Three proteins, myoglobin, cytochrome c and lysozyme, are nearly baseline resolved by the mechanism of hydrophilic interaction chromatography. A plate height as low as 3 μm, with 3900 plates, is observed in 14 mm. Varying silica particle diameter among 900, 700 and 350 nm showed that decreasing particle diameter slightly improves resolution but slows the separation. Matrix-assisted laser desorption/ionization (MALDI)-MS of the proteins after separation is demonstrated by wicking sufficient sinapinic acid into the separation medium. 相似文献
5.
Ki Hwan Bae 《中国化学快报》2009,20(11):1321-1323
Phytochemical study on the BuOH-soluble fraction of the stem bark of Populus davidiana resulted in the isolation of a new salicin derivative(1),named davidianoside.The structure was elucidated on the basis of extensive physicochemical and spectroscopic analyses. 相似文献
6.
From the transport studies in the bilayer manganites LaSr2−x
Ca
x
Mn2O7, we have found the variable-range hopping model proposed by Viret et al to be inadequate to describe the transport of charge in these materials. The polarons appear to hop to their nearest neighbors
with an activation energy, which in part is dependent on the magnetic interactions in the lattice. 相似文献
7.
8.
S Chanda Sarmishtha Bhattacharyya Tumpa Bhattacharjee SS Ghugre Swapan Kumar Basu S Muralithar RP Singh B Mukherjee RK Bhowmik SN Ray 《Pramana》2001,57(1):175-179
The high spin states in N=80 139Pr have been investigated by in-beam γ-spectroscopic techniques following the reaction 130Te (14N, 5n) reaction at E=75 MeV, using a gamma detector array, consisting of seven 23% compton-suppressed high purity germanium detectors and a multiplicity
ball of fourteen bismuth germanate elements. Based on γ-γ coincidence data, the level scheme of 139Pr has been considerably extended up to 7.2 MeV excitation. Tentative spin-parity assignments are done for the newly proposed
levels on the basis of the DCO ratios corresponding to strong gates and the available information from the earlier light ion
experiments. 相似文献
9.
MVN Murthy Urjit A Yajnik KRS Balaji G Bhattacharyya Amol Dighe Shashikant Dugad ND Hari Dass PK Kabir Kamales Kar D Indumathi John G Learned Debasish Majumdar NK Mondal MVN Murthy SN Nayak Sandip Pakvasa Amitava Raychaudhuri RS Raghavan G Rajasekaran R Ramachandran Alak K Ray Asim K Ray Saurabh Rindani HS Sharatchandra Rahul Sinha Nita Sinha S Umasankar Urjit A Yajnik 《Pramana》2000,55(1-2):347-355
We have identified some important and worthwhile physics opportunities with a possible neutrino detector located in India.
Particular emphasis is placed on the geographical advantage with a stress on the complimentary aspects with respect to other
neutrino detectors already in operation. 相似文献
10.
Sodium dialkyl phosphite reacts with non-activated alkyl halide in the presence of crown ether to give dialkyl alkyl phosphonate in moderate yield. Little or no reaction takes place in the absence of crown ether under the same conditions. In all cases, crown ether was present in catalytic amts. indicating that it behaves as a phase transfer catalyst between solid and liquid phases. The influences of structures of crown ethers, alkyl halides, dialkyl phosphites and the nature of solvent on the P-alkylation of sodium dialkyl phosphite have been investigated. 相似文献