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排序方式: 共有366条查询结果,搜索用时 15 毫秒
311.
Arie Wibowo Gusti U. N. Tajalla Maradhana A. Marsudi Glen Cooper Lia A.T.W. Asri Fengyuan Liu Husaini Ardy Paulo J.D.S. Bartolo 《Molecules (Basel, Switzerland)》2021,26(7)
Electroactive biomaterials are fascinating for tissue engineering applications because of their ability to deliver electrical stimulation directly to cells, tissue, and organs. One particularly attractive conductive filler for electroactive biomaterials is silver nanoparticles (AgNPs) because of their high conductivity, antibacterial activity, and ability to promote bone healing. However, production of AgNPs involves a toxic reducing agent which would inhibit biological scaffold performance. This work explores facile and green synthesis of AgNPs using extract of Cilembu sweet potato and studies the effect of baking and precursor concentrations (1, 10 and 100 mM) on AgNPs’ properties. Transmission electron microscope (TEM) results revealed that the smallest particle size of AgNPs (9.95 ± 3.69 nm) with nodular morphology was obtained by utilization of baked extract and ten mM AgNO3. Polycaprolactone (PCL)/AgNPs scaffolds exhibited several enhancements compared to PCL scaffolds. Compressive strength was six times greater (3.88 ± 0.42 MPa), more hydrophilic (contact angle of 76.8 ± 1.7°), conductive (2.3 ± 0.5 × 10−3 S/cm) and exhibited anti-bacterial properties against Staphylococcus aureus ATCC3658 (99.5% reduction of surviving bacteria). Despite the promising results, further investigation on biological assessment is required to obtain comprehensive study of this scaffold. This green synthesis approach together with the use of 3D printing opens a new route to manufacture AgNPs-based electroactive with improved anti-bacterial properties without utilization of any toxic organic solvents. 相似文献
312.
Sagiv Weintraub Tali Yarnitzky Shirin Kahremany Iliana Barrera Olga Viskind Kobi Rosenblum Masha Y. Niv Arie Gruzman 《Molecular diversity》2016,20(4):805-819
Protein kinase RNA-activated (PKR) plays an important role in a broad range of intracellular regulatory mechanisms and in the pathophysiology of many human diseases, including microbial and viral infections, cancer, diabetes and neurodegenerative disorders. Recently, several potent PKR inhibitors have been synthesized. However, the enzyme’s multifunctional character and a multitude of PKR downstream targets have prevented the successful transformation of such inhibitors into effective drugs. Thus, the need for additional PKR inhibitors remains. With the help of computer-aided drug-discovery tools, we designed and synthesized potential PKR inhibitors. Indeed, two compounds were found to inhibit recombinant PKR in pharmacologically relevant concentrations. One compound, 6-amino-3-methyl-2-oxo-N-phenyl-2,3-dihydro-1H-benzo[d]imidazole-1-carboxamide, also showed anti-apoptotic properties. The novel molecules diversify the existing pool of PKR inhibitors and provide a basis for the future development of compounds based on PKR signal transduction mechanism. 相似文献
313.
Arenst Andreas Arie Hans Kristianto Martin Halim Joong Kee Lee 《Journal of Solid State Electrochemistry》2017,21(5):1331-1342
Lithium ion capacitor (LIC) is a novel hybrid capacitor technology that possesses a better performance than the conventional supercapacitor, such as EDLC and lithium ion battery. However, the overall performance of LIC is limited by activated carbon’s capacity as its cathode. This work is focused on synthesize of activated carbon from Indonesian local orange peel waste for LIC cathode and its modification to perform a good electrochemical performances. Activated carbon was synthesized by ZnCl2 as impregnant with mass ratio of orange peel to ZnCl2 1:2 for 1 h at 500 °C. The obtained activated carbon possessed large surface area (1200 m2 g ?1), higher than commercial activated carbon (Merck-p.a.) with surface area of 775.6 m2 g?1. Modification was done using wet oxidation method by utilizing HNO3 65 %, H2SO4 98 %, and H2O2 30 %, with ratio 1:1 (w/w). Electrochemical properties were studied by using half cell test pouch with Li metal as reference electrode and 1 M LiPF6 (EC:EMC:DMC = 1:1:1) as electrolyte. Modification had successfully increased oxygen atoms in activated carbon samples. Surface-modified cells demonstrated a higher capacitance (almost twice in the galvanostatic test) than that of the unmodifed one due to the pseudocapacitance effect of oxygen functional groups. However, its electrochemical performance was unstable. The unmodified cell showed a stable performance with 56.3 F g?1 at current density of 0.3 mA g?1 and voltage window 2.5–4 V. 相似文献
314.
This paper presents a study on the thermal properties of a range of geopolymers in order to assess their suitability for high temperature applications such as thermal barriers, refractories and fire resistant structural members. Geopolymers were synthesised from five different fly ashes using sodium silicate and sodium aluminate solutions to achieve a set range of Si:Al compositional ratios. The thermo-physical, mechanical and microstructural properties of the geopolymers are presented and the effect of the source fly ash characteristics on the hardened product is discussed, as well as implications for high temperature applications. The amount and composition of the amorphous component (glass) of each of the fly ashes was determined by combining XRD and XRF results. It was found that the Si:Al ratio in the glass of the fly ashes strongly influenced the thermal performance of the geopolymers. Geopolymers synthesised from fly ashes with a high Si:Al (≥ 5) in the glass exhibited compressive strength gains and greater dimensional stability upon exposure to 1000 °C, whereas geopolymers synthesised from fly ashes with low Si:Al (< 2) in the glass exhibited strength losses and reduced dimensional stability upon high temperature exposure. 相似文献
315.
2 (2003←0000) R(6), C2H2 (2100011←0000000) R(12), and C2H2 (1200031←0000000) P(6) near 1064 nm using CW cavity ring-down spectroscopy and CW cavity transmission. An effective interaction length of
more than 30 km was achieved (cavity finesse ≈86000) and the sensitivity was ≈10-8 cm-1. Higher sensitivity of 3.3×10-11 cm-1/ was obtained by cavity-enhanced wavelength modulation spectroscopy. The absorption coefficients, pressure broadening coefficients,
lineshapes, line strengths, and absolute wavelengths of those lines were determined, some of them for the first time. The
measurements were carried out over a wide range of pressures from the strongly inhomogeneous to the strongly homogeneous region.
Received: 25 May 1998/Revised version: 28 July 1998 相似文献
316.
Immanuel M. Bomze Mirjam Dür Etienne de Klerk Cornelis Roos Arie J. Quist Tamás Terlaky 《Journal of Global Optimization》2000,18(4):301-320
A standard quadratic problem consists of finding global maximizers of a quadratic form over the standard simplex. In this paper, the usual semidefinite programming relaxation is strengthened by replacing the cone of positive semidefinite matrices by the cone of completely positive matrices (the positive semidefinite matrices which allow a factorization FF
T where F is some non-negative matrix). The dual of this cone is the cone of copositive matrices (i.e., those matrices which yield a non-negative quadratic form on the positive orthant). This conic formulation allows us to employ primal-dual affine-scaling directions. Furthermore, these approaches are combined with an evolutionary dynamics algorithm which generates primal-feasible paths along which the objective is monotonically improved until a local solution is reached. In particular, the primal-dual affine scaling directions are used to escape from local maxima encountered during the evolutionary dynamics phase. 相似文献
317.
Sub-micrometer polarimetry of chiral surfaces using near-field scanning optical microscopy 总被引:1,自引:0,他引:1
Dressler DH Landau A Zaban A Mastai Y 《Chemical communications (Cambridge, England)》2007,(9):945-947
In this work we have studied the optical activity of chiral crystal surfaces with polarized near-field scanning optical microscopy (NSOM); our studies clearly demonstrated that polarized NSOM can be utilized to determine chirality at crystal surfaces. 相似文献
318.
Odd-even effects in the thermotropic and optical properties of three series of chiral twin liquid crystals 总被引:1,自引:0,他引:1
Three series of novel chiral twin liquid crystals consisting of a cholesteryl and a 4'-cyanobiphenyl-4-yloxy group (III) or a 4-cyanophenoxy group (IV) and of a dihydro-cholesteryl and a 4'-cyanobiphenyl-4-yloxy group (V) connected by an alkanoate spacer with a varying number (1-7 and 10) of methylene units were synthesized and their mesogenic properties investigated. Strong odd-even effects were observed as a function of spacer length for the phase transition temperatures, the corresponding entropy changes and the selective reflection wavelengths associated with the chiral nematic phase. The compounds with an even number of methylene units have a smaller pitch than the compounds with an odd number of methylene units. Replacement of the cholesteryl group by a dihydrocholesteryl group results in an larger pitch, whereas replacement of the 4'-cyanobiphenyl-4-yloxy group by a 4-cyanophenoxy group gives a smaller pitch. 相似文献
319.
Mark A. Hink Nina V. Visser Jan Willem Borst Arie van Hoek Antonie J. W. G. Visser 《Journal of fluorescence》2003,13(2):185-188
Corrected fluorescence excitation and emission spectra have been obtained from several enhanced variants of the green fluorescent protein (EGFP) isolated from the jellyfish Aequorea victoria, blue fluorescence protein (EBFP), cyan fluorescent protein (ECFP), EGFP and yellow fluorescent protein (EYFP–citrine) and from the red fluorescent protein (DsRed) isolated from the coral species Discosoma. The spectra are stored in a database. This report describes how the spectra can be used as templates to derive the critical transfer distance for any pair of fluorescent proteins. 相似文献
320.
Arie Bialostocki 《Israel Journal of Mathematics》1982,41(3):261-273
AnN-Injector in an arbitrary finite groupG is defined as a maximal nilpotent subgroup ofG, containing a subgroupA ofG of maximal order satisfying class(A)>=2. Among other results theN-Injectors of Sym(n) are determined and shown to consist of a unique conjugacy class of subgroups of Sym(n). 相似文献