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991.
Shimon Ben‐Shabat Elias Abuganima Aliza Raziel Abraham J. Domb 《Journal of polymer science. Part A, Polymer chemistry》2003,41(23):3781-3787
Biodegradable polymers based on a blend of polycaprolactone (PCL) and aliphatic polyanhydrides with various monomer lengths were prepared to obtain desired polymer blends for use as drug carriers. The physicochemical, mechanical, and drug‐release properties of these blends were investigated by various techniques to evaluate the uniformity degree of the polymer blends to establish their potential applications in drug delivery. The results demonstrated that the heat of fusion (ΔH) of the polyanhydride or the blend is increased in relation to the length of the aliphatic chain. However, the blends had different properties than pure polyanhydride, and the crystallization degree of the blends, as expressed by the ΔH, decreased in relation to the ΔH of the pure polyanhydride. Drug‐release studies from blends of PCL and aliphatic polyanhydrides demonstrated first‐order kinetics of the release rate. Polymer degradation was independent at the polyanhydride monomer length. On the basis of theoretical calculation of the interaction factor, a blend of PCL and poly(dodecanedeoic anhydride) was chosen for further elucidation of its thermal, mechanical, and degradation properties. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3781–3787, 2003 相似文献
992.
The distribution of aluminium (Al) species was investigated in the roots of Al-tolerant Chinese cabbage (Brassica rapa L. ssp. pekinensis) by employing fast protein liquid chromatography (FPLC) with inductively coupled plasma optical emission spectrometry (ICP-OES) and electrospray tandem mass spectrometry (ES-MS-MS) detection. The cabbage was exposed to a nutrient solution that contained 10 μg cm−3 of Al3+. The results demonstrated that after 24 h of exposure, Al was quantitatively taken up by the cabbage and was distributed in different parts of the plant. 36 ± 6% of total Al was located in the roots, while the remaining 64 ± 10% was transferred to the leaves. It was found that in the roots Al was partially present in the root sap (15.5%), while the majority (84.5%) was accumulated in its apoplasmic compartments. It was further demonstrated that the proportion of Al that entered the symplasm formed a complex with organic acid. Speciation analysis by FPLC with ICP-OES detection and ES-MS-MS identification of the binding ligand indicated that Al-citrate complex was the prevailing species in the root sap.The results of the present study showed that both immobilization of Al in the apoplasmic compartments of the roots and transformation of Al3+ to Al-citrate are most likely responsible for the tolerance of Chinese cabbage (B. rapa L. ssp. pekinensis) to the toxic effects of Al3+. 相似文献
993.
DSC measurements on full thickness mice skin 总被引:1,自引:0,他引:1
Highly lipophilic basic drugs, the antiestrogens AE1 and AE2 shall be delivered transdermally. DSC as an additional tool in
combination with classic investigation techniques should be used to clarify permeation enhancement. Skin treatment with pure
solvents, polyethyleneglycol (PG) and dimethylisosorbide (DMI), slightly changed the phase transition temperatures. Formulations
containing lauric acid markedly shifted these transitions to lower temperatures, indicating a lipid-fluidising action of lauric
acid. In those cases an additional endothermic peak was observed around 40°C, which is attributed to the melting of crystalline
lauric acid. Since the DSC program started at -20°C, it is very likely that lauric acid in the skin samples crystallized.
A formulation of polyethyleneglycol and lauric acid leads to significantly higher deposition of lauric acid into the skin,
in opposition to dimethylisosorbide/lauric acid formulation. These findings correspond to the results from our in-vitro permeation
studies, where a significantly higher transdermal steady-state flux of lauric acid from polyethyleneglycol-formulation in
comparison to dimethylisosorbide-formulation was observed. By this unique combination of polyethyleneglycol and lauric acid,
the barrier is obviously modified in a way, which allows the highly lipophilic antiestrogens to permeate easily through the
skin. So, from this formulation steady-state fluxes of AE-1 were observed, representing approximately the same value compared
to the unhindered permeation through skin without stratum corneum. The grade of temperature shift on the skin lipids to lower
temperatures can be correlated with softening effects and the enhancement potential of the formulation.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
994.
对来源于紫云英根瘤菌7653R总DNA基因文库的5个互补结瘤菌株所分离到的重组质粒pNR102,pNR103,pNR108,pNR203和pNR213,EcoRⅠ酶切表明它们分别携带有一个4.68,5.01,5.04,5.10或9.38kb的外源DNA片段.选用11种内切酶进行单、双酶切分析,建立了重组质粒外源片段的酶切图谱,5个质粒都具有1.7kb的EcoRⅠ-BglⅡ片段和1.9kb的EcoRⅠ-SacⅠ片段. 相似文献
995.
996.
997.
Natural resource depletion, negative environmental effects and the challenge to secure global food security led to the establishment of the Sustainable Development Goals (SDGs). In need to explore underutilized sustainable protein sources, this study aims at isolating protein from cowpea by ultrasound-assisted extraction (UAE), where the techno-functional characteristics of the protein isolates were studied at different sonication conditions i.e., 100 W and 200 W at processing times ranging from 5 to 20 min. The US at 200 W-10 min produced the optimal results for all properties. In this process combination, there was an increase in protein yield, solubility, water-holding capacity, foaming capacity and stability, emulsion activity and stability, zeta-potential, and in-vitro protein digestibility from 31.78% to 58.96%, 57.26% to 68.85%, 3.06 g/g to 3.68 g/g 70.64% to 83.74%, 30.76% to 60.01%, 47.48% to 64.26%, 56.59% to 87.71%, –32.9 mV to −44.2 mV and 88.27% to 89.99%, respectively and particle size dropped from 763 nm to 559 nm in comparison to control. The microstructure and secondary-structure alterations of proteins caused by sonication were validated by SEM images, SDS-PAGE, and FTIR analyses. Sonication leads to acoustic cavitation and penetrate the cell walls, improving extraction from the solid to liquid phase. After sonication, the hydrophobic protein groups were exposed and proteins were partially denatured which increased its functionality. The findings demonstrated that UAE of cowpea protein improved yield, modify characteristics to fit the needs of the food industry, and contribute to achieving SDGs 2, 3, 7, 12, and 13. 相似文献
998.
A sonochemical based green synthesis method playa powerful role in nanomaterials and composite development. In this work, we developed a perovskite type of strontium titanate via sonochemical process. SrTiO3 particles were incorporated with nitrogen doped graphene oxide through simple ultrasonic irradiation method. The SrTiO3/NGO was characterized by various analytical methods. The nanocomposite of SrTiO3/NGO was modified with laser-induced graphene electrode (LIGE). The SrTiO3/NGO/LIGE was applied for electrochemical sensor towards chemotherapeutic drug detection (nilutamide). Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques have been used to examine the electrochemical performance of nilutamide (anti-cancer drug). DPV was found to be more sensitive and found to exhibit a sensitivity 8.627 µA µM−1 cm−2 for SrTiO3/NGO/LIGE with a wide linear range (0.02–892 µM) and low Limit of detection (LOD: 1.16 µM). SrTiO3/NGO/LIGE has been examined for the detection of nilutamide in blood serum and urine samples and obtained a good recovery in the range of 97.2–99.72 %. The enhanced stability and selectivity and practical application results indicates the suitability of SrTiO3/NGO/LIGE towards the detection of nilutamide drug in pharmaceutical industries. 相似文献
999.
J. Lefebvre 《Rheologica Acta》1982,21(4-5):620-625
The viscosity of solutions of four proteins (Bovine Serum Albumin, Ovalbumin,
s-1
Casein, Lysozyme), brought to the random coil conformation, has been measured over a large concentration range extending into the entanglement region. A master curve is obtained in the dilute and semi-dilute regions with the reduced variables
and
of Simha and Utracki.By using Graessley's expression for the polymer coil expansion at a given concentration in the semi-dilute region (c
* c c
**), a simple equation is established giving the relative viscosity
r
as a function of concentrationc: forc
* c c
**, ln
r
= 2a[]c
*(c/c
*)1/2a
– (2a - 1)[]c
*; wherec
* is the incipient overlap concentration, [] the intrinsic viscosity, anda the Mark-Houwink exponent for the polymer-solvent considered.This equation fits well the experimental results. The adjustment yields for the parametera values which are comprised between 0.6 and 0.7, as expected, for Bovine Serum Albumin and Ovalbumin, but very close to 0.5 for
s-1 Casein and Lysozyme. This can be explained by the fact that the molecular weights of the two latter proteins are lower than, or very close, the critical molecular weight; the critical molecular weight is estimated to be about 20000. 相似文献
1000.
Polymersomes Prepared from Thermoresponsive Fluorescent Protein–Polymer Bioconjugates: Capture of and Report on Drug and Protein Payloads 下载免费PDF全文
Chin Ken Wong Alistair J. Laos Dr. Alexander H. Soeriyadi Prof. Jörg Wiedenmann Prof. Paul M. G. Curmi Prof. J. Justin Gooding Dr. Christopher P. Marquis Prof. Martina H. Stenzel Assoc. Prof. Pall Thordarson 《Angewandte Chemie (International ed. in English)》2015,54(18):5317-5322
Polymersomes provide a good platform for targeted drug delivery and the creation of complex (bio)catalytically active systems for research in synthetic biology. To realize these applications requires both spatial control over the encapsulation components in these polymersomes and a means to report where the components are in the polymersomes. To address these twin challenges, we synthesized the protein–polymer bioconjugate PNIPAM‐b‐amilFP497 composed of thermoresponsive poly(N‐isopropylacrylamide) (PNIPAM) and a green‐fluorescent protein variant (amilFP497). Above 37 °C, this bioconjugate forms polymersomes that can (co‐)encapsulate the fluorescent drug doxorubicin and the fluorescent light‐harvesting protein phycoerythrin 545 (PE545). Using fluorescence lifetime imaging microscopy and Förster resonance energy transfer (FLIM‐FRET), we can distinguish the co‐encapsulated PE545 protein inside the polymersome membrane while doxorubicin is found both in the polymersome core and membrane. 相似文献