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排序方式: 共有1313条查询结果,搜索用时 15 毫秒
41.
Wei Cheng Nirala Singh Juan Antonio Maciá-Agulló Galen D. Stucky Eric W. McFarland Jonas Baltrusaitis 《International Journal of Hydrogen Energy》2012
The dependence of electrooxidation on experimental conditions of organic molecules was investigated to optimize the production of hydrogen from potential wastewater sources using low voltage sources (∼1 V dc). Electrooxidation on platinum, gold, and stainless steel anodes with hydrogen production on the cathode was investigated using several different organic reductants, including: methanol, ethanol, glycerol, isopropanol, propanal, glycerol, glucose, sucrose, citric acid, and propionic acid. The electrolyte pH was varied from 2 to 12 in a 1 M Na2SO4 supporting solution. At 1 V, glycerol, citric acid, ethanol and methanol were found to yield the highest currents at low pH values (pH 2 and 7) on platinum electrode, glucose on gold electrode at pH 12 in 1 M Na2SO4 solution produced the highest total current density at 1 V with measured Faradaic efficiency for 1 M glucose of 70%. The hydrogen energy production efficiency was 86%. Practical limitations of glucose oxidation at optimum experimental conditions are discussed. 相似文献
42.
Aurita Butkevičiūtė Darius Kviklys Kristina Zymonė Raimondas Raudonis Jonas Viškelis 《International Journal of Food Properties》2018,21(1):1716-1727
A new technique for the rapid detection and analysis of triterpenic compounds in apple extracts using HPLC was developed and validated. The main advantage of this technique is the short duration of the analysis – this makes this technique superior to others currently applied for the routine HPLC analysis of triterpenic compounds. The developed, optimized, and validated technique was used for the evaluation of triterpenic compounds in samples of different cultivars of apples, their peels, and flesh. In total, four triterpenic compounds were isolated and identified. Ursolic acid was the dominant compound in all the tested apple samples. The highest amounts of triterpenic compounds were detected in the peels of the ‘Lodel’ apple cultivar, and thus apples of this cultivar may be potentially useful for the isolation of individual compounds and the production of functional food and dietary supplements. 相似文献
43.
Safety requirements and the need of low-migration UV inks have received increasing attention in the packaging industry. Crucial for the development and design of low-migration UV inkjet inks for migration-sensitive applications is the polymerization degree. In this study, curing-behavior of a black, high purity packaging ink (HPP-ink) was monitored using ATR-FTIR spectroscopy. UV irradiation of HPP-ink led to changes in specific absorption bands of the FTIR spectra due to crosslinking reaction of double bonds. Changes in absorptions bands at 1,408 and 1,321 cm−1 permitted the determination of CC conversion of acrylic and vinyl double bond, independently of one another. In addition, a method was developed which allows the investigation of surface-cure and deep-cure behavior, separately. 相似文献
44.
Jonas Maximilian Müller Nicolas Rozo Lopez Enzo Alexander Klein Christian Hopmann 《Polymer Engineering and Science》2020,60(6):1324-1332
For fiber-reinforced plastics, the strain-rate dependent response is governed by the matrix behavior. In this work, the Goldberg model is considered for the epoxy matrix constitutive material model. Moreover, the strain-rate dependency is achieved by direct influence on the elastic modulus, the inelastic strain, and the material strain to failure. In addition, an anisotropic damage response is implemented and extended through a strain-rate dependent definition. Since the constitutive model relies on nonphysical parameters, a parameter study is further performed. Additional numerical investigations using a micro-mechanical model are performed. Tension and shear loading conditions are evaluated and the influence of different strain rates is explored. Furthermore, the implemented anisotropic damage model is compared and discussed against an isotropic damage model. 相似文献
45.
Jonas Ort Benedikt Kremer Linda Grüßer Romy Blaumeiser-Debarry Hans Clusmann Mark Coburn Anke Hllig Ute Lindauer 《International journal of molecular sciences》2020,21(23)
Effective pharmacological neuroprotection is one of the most desired aims in modern medicine. We postulated that a combination of two clinically used drugs—nimodipine (L-Type voltage-gated calcium channel blocker) and amiloride (acid-sensing ion channel inhibitor)—might act synergistically in an experimental model of ischaemia, targeting the intracellular rise in calcium as a pathway in neuronal cell death. We used organotypic hippocampal slices of mice pups and a well-established regimen of oxygen-glucose deprivation (OGD) to assess a possible neuroprotective effect. Neither nimodipine (at 10 or 20 µM) alone or in combination with amiloride (at 100 µM) showed any amelioration. Dissolved at 2.0 Vol.% dimethyl-sulfoxide (DMSO), the combination of both components even increased cell damage (p = 0.0001), an effect not observed with amiloride alone. We conclude that neither amiloride nor nimodipine do offer neuroprotection in an in vitro ischaemia model. On a technical note, the use of DMSO should be carefully evaluated in neuroprotective experiments, since it possibly alters cell damage. 相似文献
46.
Anna Sib Tobias M. Milzarek Alexander Herrmann Dr. Lila Oubraham Jonas I. Müller Prof. Dr. Andreas Pichlmair Prof. Dr. Ruth Brack-Werner Prof. Dr. Tobias A. M. Gulder 《Chembiochem : a European journal of chemical biology》2020,21(4):492-495
Sorbicillinoids are fungal polyketides characterized by highly complex and diverse molecular structures, with considerable stereochemical intricacy combined with a high degree of oxygenation. Many sorbicillinoids possess promising biological activities. An interesting member of this natural product family is sorbicatechol A, which is reported to have antiviral activity, particularly against influenza A virus (H1N1). Through a straightforward, one-pot chemoenzymatic approach with recently developed oxidoreductase SorbC, the characteristic bicyclo[2.2.2]octane core of sorbicatechol is structurally diversified by variation of its natural 2-methoxyphenol substituent. This facilitates the preparation of a focused library of structural analogues bearing substituted aromatic systems, alkanes, heterocycles, and ethers. Fast access to this structural diversity provides an opportunity to explore the antiviral potential of the sorbicatechol family. 相似文献
47.
Iben Sandal Stjerne Jonas Söderlund Dana Minbaeva 《International Journal of Project Management》2019,37(2):347-365
This paper introduces the notion of “temporal boundary spanning” and highlights the key role of project management in resolving temporal tensions among partners participating in interorganizational projects (IOPs). The present study, which is based on data from 93 IOPs undertaken within a major change program, relies on in-depth, semi-structured interviews, observations, and detailed analyses of written documents and procedures from those IOPs. Based on the data, we inductively develop a practice-based theory that identifies three main practices (framing, synchronizing, hyping) used to resolve the central temporal tensions observed in the studied IOPs. In that respect, the paper offers novel insights into the role and practice of project management in IOPs. 相似文献
48.
Biodegradable Ethylene‐Bis(Propyl)Disulfide‐Based Periodic Mesoporous Organosilica Nanorods and Nanospheres for Efficient In‐Vitro Drug Delivery 下载免费PDF全文
49.
Different bacterial models for in vitro induction of non‐cavitated enamel caries‐like lesions: Microhardness and polarized light miscroscopy analyses 下载免费PDF全文
Priscila Hernández De Campos Mariane Emi Sanabe Jonas Almeida Rodrigues Danilo Antonio Duarte Maria Teresa Botti Rodrigues Santos Renata Oliveira Guaré cristiane Duque Adrian Lussi Michele Baffi Diniz 《Microscopy research and technique》2015,78(6):444-451
The aim of this study was to compare different bacterial models for in vitro induction of non‐cavitated enamel caries‐like lesions by microhardness and polarized light microscopy analyses. One hundred blocks of bovine enamel were randomly divided into four groups (n = 25) according to the bacterial model for caries induction: (A) Streptococcus mutans, (B) S. mutans and Lactobacillus acidophilus, (C) S. mutans and L. casei, and (D) S. mutans, L. acidophilus, and L. casei. Within each group, the blocks were randomly divided into five subgroups according to the duration of the period of caries induction (4–20 days). The enamel blocks were immersed in cariogenic solution containing the microorganisms, which was changed every 48 h. Groups C and D presented lower surface hardness values (SMH) and higher area of hardness loss (ΔS) after the cariogenic challenge than groups A and B (P < 0.05). As regards lesion depth, under polarized light microscopy, group A presented significantly lower values, and groups C and D the highest values. Group B showed a higher value than group A (P < 0.05). Groups A and B exhibited subsurface caries lesions after all treatment durations, while groups C and D presented erosion‐type lesions with surface softening. The model using S. mutans, whether or not it was associated with L. acidophilus, was less aggressive and may be used for the induction of non‐cavitated enamel caries‐like lesions. The optimal period for inducing caries‐like lesions was 8 days. Microsc. Res. Tech. 78:444–451, 2015. © 2015 Wiley Periodicals, Inc. 相似文献
50.
G Rosenblat N Perelman E Katzir S Gal-Or A Jonas ME Nimni N Sorgente I Neeman 《Canadian Metallurgical Quarterly》1998,37(3-4):303-311
Acylated derivatives of ascorbic acid were found to be active in a number of biochemical and physiological processes. In the present study we investigated the effects of 6-O-palmitoyl ascorbate on collagen synthesis by cultured foreskin human fibroblasts. Our observations indicate a marked stimulatory effect on collagen synthesis by 6-O-palmitoyl ascorbate in the concentration range of 5-20 microM, while the synthesis stimulated by ascorbic acid was maximal at concentrations of 20-100 microM. Cells treated with 10 microM palmitoyl ascorbate for 36 h exhibited a production of collagen threefold greater than those in the presence of 10 microM ascorbic acid, and it was about the same as in cells treated with 100 microM ascorbic acid. By 48 h differences were not significant. Acylated ascorbate impaired vitality of the treated fibroblasts at concentrations exceeding 20 microM in media supplemented with 0.5% FCS. However, most of the cytotoxic effect was neutralized by FCS at a concentration of 10%. The resistance of acylated ascorbate against oxidative degradation as well as the role of free radicals in the modulation of collagen synthesis by ascorbic acid and by its derivatives is discussed. 相似文献