Evaluation of metal nanoparticle- and plastic resin-based x-ray contrast agents for kidney capillary imaging

Introduction: An essential quality of non-ionic contrast agents is that of containing in their chemical composition, elements with high atomic weight, which determine an increasing absorption of the X-ray beam and this will cause intense radiopacity. The possibilities for radiological exploration with non-ionic contrast agents are very wide. Currently the radiological examination with contrast agent no longer constitutes a risky step in medical diagnosis. Aims: To highlight the importance of using the non-ionic contrast agents Optiray 350 and Ultravist 370 in dog’s myelography and to compare the changes induced in cerebrospinal fluid and blood biochemical constituents by the administration of those non-ionic contrast substances. Materials and Methods: To determine the influence of non-ionic preparations Optiray 350 and Ultravist 370 on cerebrospinal fluid and on some haematological parameters were included in the study a total of 10 dogs. Results: Myelographies with Optiray 350 and Ultravist 370 in dogs with severe spinal condition negatively influence biochemical and haematological blood status, being necessary to take preventive measures. Optiray 350 and Ultravist 370 administration cause a slight sensitization of liver with blood biochemical parameters return to normal within 24-48 hours. Conclusion: Non-ionic contrast agents Optiray 350 and Ultravist 370 offer a very good opacification of the subarachnoidian space, but because it causes liver sensitization, we recommend using them with caution and only after a prior check of liver function.

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Volcano-Type Correlation between Particle Size and Catalytic Activity on Hydrodechlorination catalyzed by AuPd Nanoalloy

10.26434/chemrxiv.12818783 ◽

2020 ◽

Author(s):

Yuta Uetake ◽

Sachi Mouri ◽

Setsiri Haesuwannakij ◽

Kazu Okumura ◽

Hidehiro Sakurai

Keyword(s):

Catalytic Activity ◽

Metal Ion ◽

Mixing Time ◽

Metal Nanoparticle ◽

Edge Structure ◽

X Ray ◽

Rate Determining Step ◽

Transmission Electron ◽

Random Alloy ◽

X Ray Absorption

<div>Although changing the size of metal nanoparticle (NP) is a reasonable way to tune and/or enhance their catalytic activity, size-selective preparation of NP possessing random-alloy morphology has been challenging because of the differences in the ionization potential of each metal ion. This study demonstrates a time-controlled aggregation–stabilization method for a size-selective preparation of random alloy NPs composed of Au and Pd, which are stabilized by poly(<i>N</i>-vinyl-2-pyrrolidone) (PVP). By adjusting the mixing time in the presence of a small amount of PVP, the aggregation was induced to produce AuPd:PVP with sizes ranging between 1.2 and 8.2 nm at approximately 1 nm intervals. Transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and extended x-ray absorption fine structure (EXAFS) analyses clearly indicated the formation of various sizes of AuPd nanoalloys with almost the same morphology, and size-dependent catalytic activity was observed when hydrodechlorination of 4-choroanisole was performed using 2-propanol as a reducing agent. AuPd:PVP with a size of 3.1 nm exhibited the highest catalytic activity. A comparison of the absorption edges on x-ray absorption near edge structure (XANES) spectra suggested that the electronic state of the Au and Pd species correlated with their catalytic activity, presumably affecting the rate-determining step.</div><div> </div>

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