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排序方式: 共有98条查询结果,搜索用时 718 毫秒
71.
Alisa Vasilenko 《Powder Technology》2011,208(3):628-636
A method comparison study was undertaken to characterize the effects of the formulation composition on the flow and shear properties of pharmaceutically relevant powders. Fourteen blends with various concentrations of an active ingredient, magnesium stearate as a lubricant and silica as a glidant were prepared. These blends were characterized with two very different techniques: the gravitational displacement rheometer (GDR), and a rotational shear cell. The values of GDR flow index were compared to the values of principal stresses and cohesion obtained with the shear cell. These measurements are different in that the GDR operates in the gravity-driven flow regime while the shear cell utilizes an imposed normal force, which leads to a much more pronounced powder consolidation. In spite of these differences, the study demonstrated a significant correlation between the two methods, although some discrepancies were observed due to differences in the consolidation state for each technique. This observation was confirmed by measuring compressibility of these formulations with the FT4 Powder Rheometer; the presence of a cohesive component influenced the values of the shear cell principal stresses (and therefore, the shear cell flow factor) in a non-linear manner, contributing to the discrepancies in the correlation between the flow factor and the GDR flow index. Conversely, the correlation between the shear cell cohesion parameter and the GDR flow index was significantly better, as both indices test the materials at similar degree of consolidation. The study examined the limits and the ranges of applicability of each technique, offered recommendations on applications, where the use of each method was more reliable, as well as provided reasons for the methods' failure. 相似文献
72.
73.
Zoran S. Petrović Xianmei Wan Olivera Bilić Alisa Zlatanić Jian Hong Ivan Javni Mihail Ionescu Jelena Milić Darin Degruson 《Journal of the American Oil Chemists' Society》2013,90(7):1073-1078
The composition of crude algal oil was analyzed and determined by several methods. Oil was converted to polyols by ozonolysis, epoxidation, and hydroformylation. Ozonolysis gave a polyol with lighter color but a low OH number and was unsuitable for polyurethane applications. Epoxidation also improved the color and gave a polyol with an OH number around 150 mg KOH/g, which with diphenylmethane diisocyanate gave a homogeneous, rubbery, transparent sheet. Desirable rigid foams were prepared with the addition of water to the formulation. Hydroformylation was carried out successfully giving an OH number of about 150 mg KOH/g, but the polyol was black. Casting the polyurethane sheet was difficult due to the very high reactivity of the polyol. Polyurethane foam of lower quality than from epoxidation polyol was obtained. More work on optimization of the foaming system would improve the foam. Crude algal oil is a viable starting material for the production of polyols. Better results would be obtained from refined algal oils. 相似文献
74.
Dr. Rosa Purgatorio Dr. Modesto de Candia Dr. Marco Catto Dr. Mariagrazia Rullo Dr. Leonardo Pisani Prof. Nunzio Denora Prof. Antonio Carrieri Alisa A. Nevskaya Prof. Leonid G. Voskressensky Prof. Cosimo D. Altomare 《ChemMedChem》2021,16(3):589-598
Different Mannich base derivatives have been studied with the aim of addressing the poor aqueous solubility of the recently disclosed 6-phenethyl-2,3,4,5-tetrahydroazepino[4,3-b]indol-1(6H)-one ( 1 ), a human butyrylcholinesterase inhibitor (hBChE, IC5013 nM) and protective agent in NMDA-induced neurotoxicity, in in vivo assays. The N-(4-methylpiperazin-1-yl)methyl derivative 2 c showed a 50-fold increase in solubility in pH 7.4-buffered solution, high stability in serum and (half-life >24 h) and rapid (<3 min) conversion to 1 at acidic pH. Although less active than 1 , 2 c retained moderate hBChE inhibition (IC50=3.35 μM) and a significant protective effect against NMDA-induced neurotoxicity at 0.1 μM. Moreover, 2 c resulted a weaker serum albumin binder than 1 , could pass the blood–brain barrier, and exerted negligible cytotoxicity on HepG2 cells. These findings suggest that 2 c could be a water-soluble prodrug candidate of 1 for oral administration or a slow-release injectable derivative in in vivoAlzheimer's disease models. 相似文献
75.
Alisa Gufan Yoav Lehahn Erick Fredj Colin Price Rachel Kurchin 《International journal of remote sensing》2016,37(5):1055-1068
Marine stratocumulus (MSC) are shallow marine boundary layer clouds that have a significant cooling contribution to the Earth’s radiative balance. The amplitude of this cooling effect strongly depends on the properties of closed and open cells comprising MSC cloud fields. Systematic study of the underlying processes associated with cloud cell properties requires accurate and reliable cell characterization. Here we propose a method for cell segmentation of MSC clouds as observed from geostationary satellite images. The method, which is based on watershed transformation, is found to be highly efficient in segmentation of both open and closed MSC scenes. Application of the suggested methodology over a Lagrangian framework that track the clouds as they are advected by the wind and comparison of the results between pairs of consecutive images indicate that the resulted segmentation is robust and consistent. The methodology developed in this work opens the way to systematic investigation of spatiotemporal changes in MSC cloud field properties, which will improve our understanding of MSC clouds and their role in regulating Earth’s radiative budget. 相似文献
76.
Alisa G. Woods Kelly L. Wormwood Armand G. Ngounou Wetie Roshanak Aslebagh Bernard S. Crimmins Thomas M. Holsen Costel C. Darie 《Proteomics. Clinical applications》2015,9(1-2):159-168
Current directions in autism spectrum disorder (ASD) research may require moving beyond genetic analysis alone, based on the complexity of the disorder, heterogeneity and convergence of genetic alterations at the cellular/functional level. Mass spectrometry (MS) has been increasingly used to study CNS disorders, including ASDs. Proteomic research using MS is directed at understanding endogenous protein changes that occur in ASD. This review focuses on how MS has been used to study ASDs, with particular focus on proteomic analysis. Other neurodevelopmental disorders have been investigated using MS, including fragile X syndrome (FXS) and Smith-Lemli-Opitz Syndrome (SLOS), genetic syndromes highly associated with ASD comorbidity. 相似文献
77.
Charles?E.?CarraherJr.Email author Paul?P.?Slawek Michael?R.?Roner Alisa?Moric-Johnson Lindsey?C.?Miller Jeffrey?D.?Einkauf Floyd?Russell 《Journal of Inorganic and Organometallic Polymers and Materials》2016,26(6):1338-1350
The interfacial polymerization is employed to produce high polymer poly(ester ethers) from the reaction of the salt of dipicolinic acid and various organotin dihalides. They are rapidly synthesized with yield increasing as the length of the organotin alkyl chain increases. Infrared spectroscopy shows the formation of new bands derived from the Sn–O and Sn–O(CO) linkages. IR also shows that the products exist as a combination of molecular geometries about the tin atom. MALDI MS shows formation of ion fragment clusters to five and six units in length. The products show good inhibition of a variety of cancer cell lines including two pancreatic cancer cell lines. 相似文献
78.
Kameel Zuniga Alisa Isaac Sean Christy Nicole Wrice Lauren Mangum Shanmugasundaram Natesan Luke Burnett Robert Christy Christine Kowalczewski 《International journal of molecular sciences》2022,23(8)
One of the promising approaches to facilitate healing and regenerative capacity includes the application of growth-factor-loaded biomaterials. Human platelet lysate (hPL) derived from platelet-rich plasma through a freeze-thaw process has been used as a growth factor rich therapeutic in many regenerative applications. To provide sustained local delivery of the hPL-derived growth factors such as epidermal growth factor (EGF), the hPL can be loaded into biomaterials that do not degrade rapidly in vivo. Keratin (KSO), a strong filamentous protein found in human hair, when formulated as a hydrogel, is shown to sustain the release of drugs and promote wound healing. In the current study, we created a KSO biomaterial that spontaneously forms a hydrogel when rehydrated with hPL that is capable of controlled and sustained release of pro-regenerative molecules. Our study demonstrates that the release of hPL is controlled by changing the KSO hydrogel and hPL-loading concentrations, with hPL loading concentrations having a greater effect in changing release profiles. In addition, the 15% KSO concentration proved to form a stable hydrogel, and supported cell proliferation over 3 days without cytotoxic effects in vitro. The hPL-loaded keratin hydrogels show promise in potential applications for wound healing with the sustained release of pro-regenerative growth factors with easy tailoring of hydrogel properties. 相似文献
79.
In an attempt to correlate the incorporation of fatty acids (FA) of different chain length into liver and biliary lipids’
isolated rat livers were perfused for 2 h with Krebs-Ringer bicarbonate containing 1% albumin and 10 μmol of [1-14C]-labeled FA: C2’ C8’ C10’ C12’ C16’ and C18∶1. One to 1.36 μmol of medium-chain fatty acids (MCFA’ C8’ C10’ and C12) and 6.6 μmol of long-chain FA (LCFA) were incorporated into liver lipids’ 40% of the latter into phosphatidylcholine (PC).
14C-acetate (13 nmol) was incorporated into biliary cholesterol; 14C-MCFA contributed only 3.2–5 nmol; LCFA did not lead to newly synthesized cholesterol. Newly synthesized liver PC (2.75 to
3.25%) and newly synthesized liver cholesterol (6.5 to 10%) were secreted into bile. The specific radioactivity of biliary
PC after infusion of all-saturated FA was 3.8–6.8 times higher than that of liver PC; for C18∶1 it was only 1.7-fold. The specific radioactivity of biliary cholesterol’ as compared to liver cholesterol’ was 12 times higher
for C2 and five times higher for MCFA. This indicates that a considerable proportion of the newly synthesized lipids was secreted
into bile prior to significant mixing with preexisting liver PC and cholesterol pools. liver PC contained 8% of unchanged
14C−C12; while 14C−C10 was not detected. Biliary PC’ in contrast’ contained 18% of unchanged 14C−C12 and 3% 14C−C10. These results suggest that after prolonged infusion of medium-chain triacylglycerols/longchain triacylglycerols to patients’
biliary PC may become enriched with MCFA. In addition’ the oxidation of these FA may provide C-2 units which increase cholesterol
synthesis. 相似文献
80.
Sergejs Beluns Oskars Platnieks Sergejs Gaidukovs Olesja Starkova Alisa Sabalina Liga Grase Vijay Kumar Thakur Gerda Gaidukova 《International journal of molecular sciences》2021,22(23)
Cellulose materials and products are frequently affected by environmental factors such as light, temperature, and humidity. Simulated UV irradiation, heat, and moisture exposure were comprehensively used to characterize changes in cellulose nanopaper (NP) tensile properties. For the preparation of NP, high-purity cellulose from old, unused filter paper waste was used. Lignin and xylan were used as sustainable green interface engineering modifiers for NP due to their structural compatibility, low price, nontoxic nature, and abundance as a by-product of biomass processing, as well as their ability to protect cellulose fibers from UV irradiation. Nanofibrillated cellulose (NFC) suspension was obtained by microfluidizing cellulose suspension, and NP was produced by casting films from water suspensions. The use of filler from 1 to 30 wt% significantly altered NP properties. All nanopapers were tested for their sensitivity to water humidity, which reduced mechanical properties from 10 to 40% depending on the saturation level. Xylan addition showed a significant increase in the specific elastic modulus and specific strength by 1.4- and 2.8-fold, respectively. Xylan-containing NPs had remarkable resistance to UV irradiation, retaining 50 to 90% of their initial properties. Lignin-modified NPs resulted in a decreased mechanical performance due to the particle structure of the filler and the agglomeration process, but it was compensated by good property retention and enhanced elongation. The UV oxidation process of the NP interface was studied with UV-Vis and FTIR spectroscopy, which showed that the degradation of lignin and xylan preserves a cellulose fiber structure. Scanning electron microscopy images revealed the structural formation of the interface and supplemented understanding of UV aging impact on the surface and penetration depth in the cross-section. The ability to overcome premature aging in environmental factors can significantly benefit the wide adaption of NP in food packaging and functional applications. 相似文献