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排序方式: 共有199条查询结果,搜索用时 15 毫秒
121.
Tosic acid on silica gel (TsOH-SiO2) was synthesized and characterized using microscopic and spectroscopic techniques such as powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and FT-IR spectroscopy. Thermal behaviour of the catalyst was investigated by differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. TsOH-SiO2 showed excellent catalytic activity for the Knoevenagel condensation and was recyclable for six cycles. 相似文献
122.
Polyether ether ketone (PEEK) is a semi-crystalline thermoplastic polymer having excellent mechanical and thermal properties. Exposure of this polymer to aliphatic and aromatic solvents can lead to degradation or swelling of the polymeric material. The present work described the plasticization and stability analysis of semi-crystalline PEEK under different aromatic and aliphatic solvent environment. A variety of solvents (acetone, benzene, benzyl alcohol, chloroform, methanol, and toluene), based on their Hildebrand’s Solubility Parameter, were chosen for investigation. The physico-chemical characteristics of virgin and treated polymeric samples were investigated using Gas Chromatography–Mass Spectrometry (GC–MS), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Fourier Transform Infrared Spectroscopy (FTIR) techniques. The results indicated that the solvent exposure did not significantly affect the thermal behavior and chemical structure of the polymer. However, it seems that certain components of the polymer were leached into the solvent phase as revealed by the GC–MS analysis. The present study identified PEEK as a potentially suitable polymer for the applications where high resistance to aliphatic and aromatic solvents is needed. 相似文献
123.
Saima Arshed Anjan Biswas Mahmoud Abdelaty Qin Zhou Seithuti P. Moshokoa Milivoj Belic 《Chinese Journal of Physics (Taipei)》2018,56(6):2879-2886
This paper employs two integration procedures to obtain soliton solutions to the perturbed Gerdjikov–Ivanov equation. They are G′/G2–expansion method and the sine–cosine method. Bright, dark and singular solitons are revealed along with a few of the combo–soliton solutions. The existence criteria of these solitons are also given. 相似文献
124.
Application of capillary immunoelectrophoresis revealed an age‐ and gender‐dependent regulated expression of PrPC in liver 下载免费PDF全文
Amandeep Singh Arora Saima Zafar Otto Kollmar Franc Llorens Waqas Tahir Sven Vanselow Prateek Kumar Mary Jo Schmerr Matthias Schmitz Inga Zerr 《Electrophoresis》2015,36(24):3026-3033
The cellular prion protein (PrPC) is a glycoprotein, anchored to the plasma membrane and abundantly expressed in the central nervous system. The expression of PrPC in the peripheral tissues is low and only little information is available on its functions in the nonneuronal tissues. The antioxidant function of PrPC during the activation of hepatic stellate cells has already been reported. Therefore, the aim of the study was to expand our knowledge on the functions of PrPC by detailed characterization of its expressional profile in the liver. In a combined strategy by using capillary immunoelectrophoresis and standard techniques, we have shown a sexually dimorphic expression of PrPC in mice and human liver tissues. Further, we showed a significant age‐dependent upregulation of PrPC expression in the liver of 14‐ and 9‐month‐old mice as compared to 3 months of age. Therefore, this study may provide new insights into the gender‐specific role of PrPC in the liver, which may further be linked to its protective role against oxidative stress during aging. In addition, the current study also shows an application of immunoelectrophoresis with a low coefficient of variation to analyze the miniscule amount of PrPC in the mouse liver tissue. 相似文献
125.
Choudhary MI Jalil S Todorova M Trendafilova A Mikhova B Duddeck H Atta-ur-Rahman 《Natural product research》2007,21(11):1032-1036
Achillea species are widely used in folk medicine for treatment of inflammatory diseases. The inhibitory effect on the human neutrophils respiratory burst activity of total extracts, their fractions and some main constituents of the flower heads from Achillea asplenifolia, A. collina and A. distans belonging to A. millefolium complex of Bulgarian origin, were tested by the modified method of Tan and Berridge. Seven from the investigated fractions showed activity similar or higher than that of indomethacine and might be evaluated as nonsteroidal anti-inflammatory agents. 相似文献
126.
Mubeen Muhammad Khalid Muhammad Adnan Mukhtar Maria Shahrum Saba Zahra Shanila Shabbir Saima Iqbal Azhar 《Journal of fluorescence》2021,31(4):1055-1063
Journal of Fluorescence - Employing natural or artificial sunscreens is essential to protect the skin from ultraviolet radiations that cause premature aging and develop melanoma and other forms of... 相似文献
127.
R. Alan Howie Abdul Jabbar John R. Lewis Shaikh S. Nizami Craig F. Ritchie 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(9):o516-o519
The title compounds, C15H13NO4, (I), and C13H9NO, (II), are produced, along with the corresponding anilines, by the reduction of the appropriate o‐nitrobenzophenones. In (I), the planar benzisoxazole and phenol fragments are tilted relative to one another by a rotation of 53.02 (14)° about the bond joining them, and the molecules are linked into chains by phenol O—H...N and phenyl C—H...Ooxazole hydrogen bonds. The cell of (II) (space group I2/c) contains eight molecules in general positions, four more in the 2b sites, with twofold axial symmetry that induces a degree of disorder, and a further four as centrosymmetric pairs of complete molecules, each with an occupancy of one‐half. The relative tilt of the planar fragments varies slightly from one molecule to another but is much less than that in (I), ranging from 8.8 (8) to 12.58 (15)°. 相似文献
128.
Faiq Amin Mahmoud A. A. Ibrahim Syed Rizwan-ul-Hasan Saima Khaliq Gamal A. Gabr Muhammad Asra Khan Peter A. Sidhom Prashant Tikmani Ahmed M. Shawky Saara Ahmad Syed Hani Abidi 《Molecules (Basel, Switzerland)》2022,27(24)
Background: The current study utilizes in silico molecular docking/molecular dynamics to evaluate the binding affinity of apigenin and safranal with 5HT1AR/5HT2AR, followed by assessment of in vivo effects of these compounds on depressive and anxious behavior. Methods: The docking between apigenin and safranal and the 5HT1A and 5HT2A receptors was performed utilizing AutoDock Vina software, while MD and protein-lipid molecular dynamics simulations were executed by AMBER16 software. For in vivo analysis, healthy control (HC), disease control (DC), fluoxetine-, and apigenin-safranal-treated rats were tested for changes in depression and anxiety using the forced swim test (FST) and the elevated plus-maze test (EPMT), respectively. Results: The binding affinity estimations identified the superior interacting capacity of apigenin over safranal for 5HT1A/5HT2A receptors over 200 ns MD simulations. Both compounds exhibit oral bioavailability and absorbance. In the rodent model, there was a significant increase in the overall mobility time in the FST, while in the EPMT, there was a decrease in latency and an increase in the number of entries for the treated and HC rats compared with the DC rats, suggesting a reduction in depressive/anxiety symptoms after treatment. Conclusions: Our analyses suggest apigenin and safranal as prospective medication options to treat depression and anxiety. 相似文献
129.
Jabbar A Khoon AT Hui TX Schaeffner BC Jex AR Nolan MJ Lopata A Gasser RB Beveridge I 《Electrophoresis》2012,33(3):499-505
Anisakidosis is an important fish-borne disease caused by the larvae of anisakid nematodes, which affects humans and a range of other animals. The accurate identification of members of this nematode group is central to investigating the epidemiology of the parasites and in the surveillance and control of anisakidosis. It is now well known that morphological identification alone does not allow specific identification, particularly of larval stages. To better understand the epidemiology of anisakid nematodes in southern Australian fishes and the potential risks posed to human health, a survey of 50 specimens of the commercially important fish, Sillago flindersi, from Bass Strait, Australia was conducted. We characterised anisakid larvae by PCR-coupled mutation scanning, sequencing and phylogenetic analyses of the first and second internal transcribed spacers (ITS-1 and ITS-2) of nuclear ribosomal DNA. This study revealed that 92% of the S. flindersi examined were infected with anisakids (n=194), which were represented by seven genotypes. Phylogenetic analyses of the genotypes defined herein, together with reference sequence for Anisakis pegreffii and Hysterothylacium sp. from public databases (i.e. GenBank), revealed the presence of A. pegreffii (n=24), Hysterothylacium larval type IV (n=90) and Hysterothylacium larval type VIII (n=80) in S. flindersi. Thus, the PCR-coupled mutation scanning approach employed herein is an effective tool for the genetic characterisation of anisakid nematodes for diagnostic and analytical purposes (nucleotide sequences reported in this paper are available in the GenBank database under accession nos. JN631796-809). 相似文献
130.
Sharma N Sharma A Shard A Kumar R Saima Sinha AK 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(37):10350-10356
Tandem reactions that involve chemoselective Knoevenagel/Perkin condensation-decarboxylation-Heck/Suzuki coupling or Heck-aldol sequences have been achieved. This enabled the first concise and efficient synthesis of several important hydroxy-functionalized compound classes, such as stilbene-cinnamoyl hybrids (potent protein tyrosine phosphatase1B inhibitors), cinnamoyl-cinnamic acid hybrids, asymmetric distyrylbenzenes, and biarylstyrenes. Previously reported synthesis require multiple steps and protection/deprotection manipulations. 相似文献