The complexes formed on the reaction of various metal ions viz., Cu(II) and Cu(I) with phenol derivatives viz. catechol, chlorogenic acid (CGA), hydroquinone and n-propyl gallate (nPG) were established by UV-visible spectroscopy. The metal/ligand complexing ratio and complexation constants have been determined. Further, we showed that nanoparticles of Cu can be prepared from metal-phenol complexes in the presence of a protein (gelatin) by γ-irradiation showing that the reduction is metal ion centered. Formation of Ag nanoparticles was also observed on photo-irradiation with xenon lamp in the presence of dihydroxy benzene. The Ag and Cu nanoparticles were characterized by transmission electron microscopy (TEM) and UV-visible absorption spectroscopy. TEM technique showed the presence of Cu and Ag nanoparticles with average size of 20 and 30 nm, respectively. 相似文献
Emeraldine base (EB) polymer–ZnO nanoparticles composite films has been synthesized by solution casting technique on ITO-coated
glass substrate and characterized by XRD, FTIR and TEM for their structure and morphology. Dielectric behaviour of these composite
films has been investigated in the very low frequency region to medium frequency region (1 kHz–1 MHz). The dielectric constant
of the composite with 30% nanoparticles is almost one-tenth of the pure EB. The dielectric value becomes constant in the frequency
region greater than 400 kHz. The change in dielectric behaviour of the composite is explained on the basis of multilayered
interface formed between the ZnO nanoparticles and emeraldine chains. Nanoparticles have high energy surface which is responsible
for the decrease of free volume for the orientation of polymer chains consequently decrease in dielectric constant of the
composite. TEM images shows about 10 nm ZnO particles embedded in the emeraldine matrix. From the XRD data it has been observed
that the lattice parameters of ZnO have been modified due to the alignment of polymer chains along the basal planes of the
nanoparticles. The shift of N=Q=N and N–B–N vibration bands to higher wave number in IR indicates that interaction between
emeraldine chain and nanoparticles which provides stability to emeraldine matrix. 相似文献
Molecular Diversity - Microbes possess a tremendous potential to interact with their surroundings and have continued to shape the future of all life forms existing on earth. Of all the groups of... 相似文献
Results of the preliminary study on the evaluation of the role of magnetization transfer imaging (MTI) of prostate in men who had raised prostate-specific antigen (PSA) (>4 ng/ml) or abnormal digital rectal examination (DRE) are reported. MT ratio (MTR) was calculated for 20 patients from the hyper- (normal) and hypo-intense regions (area suspicious of malignancy as seen on T2-weighted MRI) of the peripheral zone (PZ) and the central gland (CG) at 1.5 T. In addition, MTR was calculated for three healthy controls. Mean MTR was also calculated for the whole of the PZ (including hyper- and hypo-intense area) in all patients. Out of 20 patients, biopsy revealed malignancy in 12 patients. Mean MTR value (8.29+/-3.49) for the whole of the PZ of patients who were positive for malignancy on biopsy was statically higher than that observed for patients who were negative for malignancy (6.18+/-3.15). The mean MTR for the whole of the PZ of controls was 6.18+/-1.63 and is similar to that of patients who were negative for malignancy. Furthermore, for patients who showed hyper- (normal portion) and hypo-intense (region suspicious of malignancy) regions of the PZ, the MTR was statistically significantly different. These preliminary results reveal the potential role of MT imaging in the evaluation of prostate cancer. 相似文献
The current investigation deciphers aggregation pattern of gold nanoparticles (AuNPs) and lipid-treated AuNPs when subjected to aqueous sodium chloride solution with increasing ionic strengths (100–400 nM). AuNPs were synthesized using 0.29 mM chloroauric acid and by varying the concentrations of trisodium citrate (AuNP1 1.55 mM, AuNP2 3.1 mM) and silver nitrate (AuNP3 5.3 μM, AuNP4 10.6 μM) with characteristic LSPR peaks in the range of 525–533 nm. TEM analysis revealed AuNPs to be predominantly faceted nanocrystals with the average size of AuNP1 to be 35?±?5 nm, AuNP2 15?±?5 nm, AuNP3 30?±?5 nm, and AuNP4 30?±?5 nm and the zeta-average for AuNPs were calculated to be 31.23, 63.80, 26.08, and 28 nm respectively. Induced aggregation was observed within 10 s in all synthesized AuNPs while lipid-treated AuNP2 (AuNP2-L) was found to withstand ionic interferences at all concentration levels. However, lipid-treated AuNPs synthesized using silver nitrate and 1.55 mM trisodium citrate (AuNP3, AuNP4) showed much lower stability. The zeta potential values of lipid-treated AuNPs (AuNP1-L-1x/200, ??17.93?±?1.02 mV; AuNP2-L-1x/200, ??21.63?±?0.70; AuNP3-L-1x/200, ??14.54?±?0.90; AuNP3-L-1x/200 ??13.77?±?0.83) justified these observations. To summarize, AuNP1 and AuNP2 treated with lipid mixture 1 equals or above 1x/200 or 1x/1000 respectively showed strong resistance against ionic interferences (up to 400 mM NaCl). Use of lipid mixture 1 for obtaining highly stable AuNPs also provided functional arms of various lengths which can be used for covalent coupling.
Flavonoids are biologically active natural products of great interest for their potential applications in functional foods and pharmaceuticals. A hesperetin-7-O-glucoside inclusion complex with β-cyclodextrin (HEPT7G/βCD; SunActive® HCD) was formulated via the controlled enzymatic hydrolysis of hesperidin with naringinase enzyme. The conversion rate was nearly 98%, estimated using high-performance liquid chromatography analysis. The objective of this study was to investigate the stability, solubility, and spectroscopic features of the HEPT7G/βCD inclusion complex using Fourier-transform infrared (FTIR), Raman, ultraviolet–visible absorption (UV–vis), 1H- and 13C- nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), liquid chromatography/mass spectroscopy (LC–MS), scanning electron microscopy (SEM), and powdered X-ray diffraction (PXRD) spectroscopic techniques including zeta potential, Job’s plot, and phase solubility measurements. The effects of complexation on the profiles of supramolecular interactions in analytic features, especially the chemical shifts of β-CD protons in the presence of the HEPT7G moiety, were evaluated. The stoichiometric ratio, stability, and solubility constants (binding affinity) describe the extent of complexation of a soluble complex in 1:1 stoichiometry that exhibits a greater affinity and fits better into the β-CD inner cavity. The NMR spectroscopy results identified two different configurations of the HEPT7G moiety and revealed that the HEPT7G/βCD inclusion complex has both –2S and –2R stereoisomers of hesperetin-7-O-glucoside possibly in the –2S/–2R epimeric ratio of 1/1.43 (i.e., –2S: 41.1% and –2R: 58.9%). The study indicated that encapsulation of the HEPT7G moiety in β-CD is complete inclusion, wherein both ends of HEPT7G are included in the β-CD inner hydrophobic cavity. The results showed that the water solubility and thermal stability of HEPT7G were apparently increased in the inclusion complex with β-CD. This could potentially lead to increased bioavailability of HEPT7G and enhanced health benefits of this flavonoid. 相似文献
Journal of Solid State Electrochemistry - In the present investigation, we have synthesized samarium (Sm) nanoparticles (NPs) and anchored them onto the surface of CuO:CoO nanostructure (NS) by... 相似文献