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991.
Martina Palomba Italo Franco Coelho Dias Ornelio Rosati Francesca Marini 《Molecules (Basel, Switzerland)》2021,26(11)
In recent years, vinyl selenones were rediscovered as useful building blocks for new synthetic transformations. This review will highlight these advances in the field of multiple-bond-forming reactions, one-pot synthesis of carbo- and heterocycles, enantioselective construction of densely functionalized molecules, and total synthesis of natural products. 相似文献
992.
Background: Filtration of osmotic solution affects selective penetration during osmotic dehydration (OD), and after drying is finished, this can influence the chemical composition of the material, which is also modified by OD. Methods: Osmotic dehydration was carried out in filtrated and non-filtrated concentrated chokeberry juice with the addition of mint infusion. Then, this underwent convective drying, vacuum-microwave drying and combined convective pre-drying, followed by vacuum-microwave finishing drying. Drying kinetics were presented and mathematical models were selected. The specific energy consumption for each drying method was calculated and the energy efficiency was determined. Results and Discussion: The study revealed that filtration of osmotic solution did not have significant effect on drying kinetics; however, it affected selective penetration during OD. The highest specific energy consumption was obtained for the samples treated by convective drying (CD) (around 170 kJ·g−1 fresh weight (fw)) and the lowest for the samples treated by vacuum-microwave drying (VMD) (around 30 kJ·g−1 fw), which is due to the differences in the time of drying and when these methods are applied. Conclusions: Filtration of the osmotic solution can be used to obtain the desired material after drying and the VMD method is the most appropriate considering both phenolic acid content and the energy aspect of drying. 相似文献
993.
Lukas Martin Müller-Wirtz Daniel Kiefer Sven Ruffing Timo Brausch Tobias Hüppe Daniel I. Sessler Thomas Volk Tobias Fink Sascha Kreuer Felix Maurer 《Molecules (Basel, Switzerland)》2021,26(11)
Exhaled aliphatic aldehydes were proposed as non-invasive biomarkers to detect increased lipid peroxidation in various diseases. As a prelude to clinical application of the multicapillary column–ion mobility spectrometry for the evaluation of aldehyde exhalation, we, therefore: (1) identified the most abundant volatile aliphatic aldehydes originating from in vitro oxidation of various polyunsaturated fatty acids; (2) evaluated emittance of aldehydes from plastic parts of the breathing circuit; (3) conducted a pilot study for in vivo quantification of exhaled aldehydes in mechanically ventilated patients. Pentanal, hexanal, heptanal, and nonanal were quantifiable in the headspace of oxidizing polyunsaturated fatty acids, with pentanal and hexanal predominating. Plastic parts of the breathing circuit emitted hexanal, octanal, nonanal, and decanal, whereby nonanal and decanal were ubiquitous and pentanal or heptanal not being detected. Only pentanal was quantifiable in breath of mechanically ventilated surgical patients with a mean exhaled concentration of 13 ± 5 ppb. An explorative analysis suggested that pentanal exhalation is associated with mechanical power—a measure for the invasiveness of mechanical ventilation. In conclusion, exhaled pentanal is a promising non-invasive biomarker for lipid peroxidation inducing pathologies, and should be evaluated in future clinical studies, particularly for detection of lung injury. 相似文献
994.
Oana-Viorela Nistor Carmen Alina Bolea Doina-Georgeta Andronoiu Mihaela Cotrle Nicoleta Stnciuc 《Molecules (Basel, Switzerland)》2021,26(11)
Sea buckthorn (Hippophaė rhamnoides L.) is recognized as a valuable source of vitamin C and antioxidants, frequently used as nutraceuticals and cosmeceuticals. In the present study, attempts are made to produce and characterize a novel type of marmalade using sea buckthorn berries processed at 102 °C into marmalade in two combinations, with whole cane or stevia sugar. Changes in the phytochemical profile, antioxidant activity, color, shelf-life, texture, microbiological, and sensorial characteristics were determined. The total carotenoids content in the marmalades were significantly different, with values of 0.91 ± 0.03 mg/g dry weight (DW) in the sample with whole sugar cane (Cz) and 2.69 ± 0.14 mg/g DW in the sample with Stevia sugar (Cs). Significant values of polyphenols were found, of 59.41 ± 1.13 mg GAE/g DW in Cz and 72.44 ± 2.31 mg GAE/g DW in Cs, leading to an antioxidant activity of 45.12 ± 0.001 μMol Trolox/g DW and 118.07 ± 0.01 μMol Trolox/g DW, respectively. Accelerated storage study showed a decrease in all the phytochemicals, however no significant changes were found in antioxidant activity. Values of <100 CFU/g for yeasts and molds and <5 CFU/g for Enterobacteriaceae after 21 days of storage at the room temperature of the marmalades were determined. The sensorial and color results were more than acceptable. Overall, the results highlighted the potential of using sea buckthorn as a potential rich source of bioactive compounds to be used in the sugar-based products manufacturing. 相似文献
995.
996.
997.
真空紫外光电离源(VUV-PI)是一种普适性的质谱软电离源,真空紫外光电离质谱谱图无碎片、易解析、灵敏度高,适合于在线快速分析。真空紫外光电离质谱根据分析对象不同可以直接采用单光子电离或添加掺杂剂实现化学电离,能实现气、液、固体分析,也可实现成像分析。该文介绍了真空紫外光电离源的电离原理、光源类型,分析了光电离质谱灵敏度的影响因素及其技术改进措施,并阐述了真空紫外光电离质谱技术在环境污染物、化工产物在线分析、国家安全分析以及生物医学分析中的相关应用研究。最后,总结了真空紫外光电离源的优缺点,并对真空紫外光电离技术在性能和应用方面的发展前景进行了展望。 相似文献
998.
Xiao-Qian Xu Dr. Li-Hui Cao Yan Yang Xiang-Tian Bai Fang Zhao Dr. Zhen-Hong He Dr. Zheng Yin Prof. Dr. Yang-Min Ma 《化学:亚洲杂志》2021,16(2):142-146
Over the past two decades, progress in chemistry has generated various types of porous materials for removing iodine (129I or 131I) that can be formed during nuclear energy generation or nuclear waste storage. However, most studies for iodine capture are based on the weak host-guest interactions of the porous materials. Here, we present two cationic nonporous macrocyclic organic compounds, namely, MOC-1 and MOC-2 , in which 6I- and 8I− were as counter anions, for highly efficient iodine capture. MOC-1 and MOC-2 were formed by reacting 1,1′-diamino-4,4′-bipyridylium di-iodide with 1,2-diformylbenzene or 1,3-diformylbenzene, respectively. The presence of a large number of I− anions results in high I2 affinity with uptake capacities up to 2.15 g ⋅ g−1 for MOC-1 and 2.25 g ⋅ g−1 for MOC-2 . 相似文献
999.
Synthesis and characterization of a family of layered trichalcogenides for assisted hydrogen photogeneration 下载免费PDF全文
Three layered trisulfides (TiS3, ZrS3, HfS3) have been synthesized by solid–gas reaction between metal and sulfur in a vacuum sealed ampoule at 550 °C during 60 h. The samples used in this work were prepared from a colloidal suspension of powder of each one of the metal trisulfides (MS3, M = Ti, Zr, Hf) in ethanol and deposited on titanium disks and quartz substrates by ”drop coating” technique. These samples have been characterized by X‐ray diffraction, energy dispersive analysis of X‐ray and scanning electron microscopy. The obtained direct optical band gaps are 1.0 ± 0.1 eV, 2.0 ± 0.1 eV and 2.2 ± 0.1 eV for TiS3, ZrS3 and HfS3, respectively. Photoelectrochemical measurements in 0.5 M Na2SO3 have been carried out to characterize the MS3/electrolyte interface. The flat‐band potentials (Vfb) vs. Ag/AgCl measured by electrochemical impedance spectroscopy (EIS) are –0.84 ± 0.02 V (TiS3), –0.93 ± 0.02 V (ZrS3) and –0.92 ± 0.02 V (HfS3). Hydrogen generation was investigated in a photoelectrochemical cell (PEC) with MS3 as photoanodes under white light illumination of 200 ± 20 mW/cm2 at external bias potentials of 0.3 V vs. Ag/AgCl. Hydrogen evolution flows have been quantified by quadrupole mass spectrometry (QMS) reaching instantaneous values up to 19 ± 2 nmol H2/min cm2 with TiS3 as photoanode. 相似文献
1000.
Laredo E Prutsky N Bello A Grimau M Castillo RV Müller AJ Dubois P 《The European physical journal. E, Soft matter》2007,23(3):295-303
Thermally stimulated depolarization currents, TSDC, wide-angle X-ray scattering, WAXS, differential scanning calorimetry,
DSC, and polarized light optical microscopy, PLOM, have been used to examine poly(L-lactide)-b -poly(
-caprolactone) diblock copolymers in a wide composition range. Both components are crystallizable and the miscibility in
the amorphous phase has been determined from the behavior of the primary relaxations which are the dielectric manifestation
of the glass transition, and also from the superstructural morphology revealed by PLOM and the compositional dependence of
the melting points as determined by DSC. Distinct segmental mobilities in the amorphous phase which can be well resolved by
TSDC are present; the
mode of the slower component shifts to lower temperatures as the PCL content increases while the glass transition of neat
PCL is present for all compositions. A relaxation times bimodal distribution is apparent for PCL-rich copolymers. The composition
dependence of the multiple glass transitions detected in these weakly segregated copolymers are predicted by the self-concentration
model for a miscible blend made of components with a large Tg contrast. 相似文献