scholarly journals A cocktail of 165Er(iii) and Gd(iii) complexes for quantitative detection of zinc using SPECT and MRI

2018 ◽  
Vol 54 (55) ◽  
pp. 7597-7600 ◽  
Author(s):  
Kyangwi P. Malikidogo ◽  
Isidro Da Silva ◽  
Jean-François Morfin ◽  
Sara Lacerda ◽  
Laurent Barantin ◽  
...  
Keyword(s):  
Mr Imaging ◽  
Metal Ion ◽  
Quantitative Detection ◽  
Zinc Determination

Quantitative zinc determination by nuclear and MR imaging using two Ln3+ complexes, including purified 165Er3+, indispensable for metal ion quantification.

scholarly journals Diffusion Tensor Imaging in Rat Models of Preclinical Diabetic Nephropathy: A Preliminary Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaoyan Hu ◽  
Min Kuang ◽  
Bo Peng ◽  
Yang Yang ◽  
Wei Lin ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Diffusion Tensor Imaging ◽  
Mr Imaging ◽  
Serum Creatinine ◽  
Fractional Anisotropy ◽  
Diffusion Coefficients ◽  
Diffusion Tensor ◽  
Quantitative Detection ◽  
Apparent Diffusion Coefficients ◽  
Apparent Diffusion

PurposeThis study aimed to investigate the value of diffusion tensor imaging to assess renal injury in a rat model of preclinical diabetic nephropathy.MethodsTwenty-eight male Sprague Dawley rats were divided into two groups: the normal control (NC) group of 10 rats and the diabetic nephropathy (DN) group of 18 rats. Eight weeks after diabetes induction by streptozotocin, 3.0-T magnetic resonance (MR) imaging (b = 0 and 600 s/mm2, 15 diffusion directions) using a 32-channel knee coil was performed. After MR imaging, we measured serum creatinine, and collected double kidney tissues for pathology. The apparent diffusion coefficients(ADC) and fractional anisotropy(FA) values of the renal cortex and medulla were calculated for all kidneys. Physiological parameters, laboratory parameters, and imaging results were compared between the two groups.ResultsAll DN group animals developed hyperglycemia, polyuria, and emaciation. Serum creatinine was not significantly different between the groups (P > 0.05). Urinary albumin at 2, 4, and 8 weeks was higher in the DN group than in the NC group but <20 µg/min (P < 0.05). Pathologically, renal damage in the DN rats was observed. The ADC value was significantly increased in DN animals in the cortex (1.75×10-3mm2/s),medulla(1.53×10-3mm2/s)compared with NC group(cortex, 1.52×10-3mm2/s; medulla,1.35×10-3mm2/s). The FA value was significantly reduced in DN animals in the cortex (0.21),medulla(0.25)compared with NC group(cortex,0.26;medulla,0.3).ConclusionsIncreased apparent diffusion coefficients and decreased fractional anisotropy values on diffusion tensor imaging were associated with preclinical DN. Diffusion tensor imaging may be useful in early, non-invasive, quantitative detection, and therapy monitoring of DN.

scholarly journals Copper Ion Detection Method Based on a Quantum Dot Fluorescent Probe

2021 ◽  
Author(s):  
Pu YANG ◽  
Feng DONG ◽  
Yaguang YU ◽  
Jiahui SHI ◽  
Ming SUN
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Fluorescence Quenching ◽  
Linear Relationship ◽  
Fluorescent Probe ◽  
Metal Ion ◽  
Copper Ion ◽  
Quantitative Detection ◽  
Correction Coefficient ◽  
Modeling And Analysis

The heavy metal ion Cu2+ was used as the research object in this study. Cu2+ was detected using a cysteine- and glutathione-modified cadmium telluride quantum dot solution. Compounds of Cu2+ and modified quantum dots on the surface caused the fluorescence quenching of quantum dots. A linear relationship existed between the concentration and the intensity of the change in fluorescence quenching. Using this linear relationship, the quantitative detection of the Cu2+ content in the solution by quantum dots was achieved; the detection band was 476-800 nm. Under optimized conditions, the detection limit of the method was 3.58×10-5 mol/L (S/N=3, n=11), and the linear range was 3×10-7 to 8×10-4 mol/L. In a certain experimental environment, standard normal variate preprocessing of the characteristic band and partial least squares modeling and analysis yielded good self-prediction and actual prediction abilities. The correction coefficient was 0.9006. The RMSEC was 8.83084 µmol/L, the determination coefficient of the validation set was 0.8686, and the RMSEP was 5.4320 µmol/L. The results showed that the modeling effect was good in the experiment, the operation was simple and convenient, and the experiment was fast, reliable, and nonpolluting, indicating that the method of detecting Cu2+ using a quantum dot fluorescent probe was feasible.

Aspects of high-resolution imaging with a scanning ion microprobe

1986 ◽  
Vol 44 ◽  
pp. 750-751
Author(s):  
R. Levi-Setti ◽  
J. M. Chabala ◽  
Y. L. Wang
Keyword(s):  
Metal Ion ◽  
Secondary Ion Mass Spectrometry ◽  
Chromatic Aberration ◽  
Ion Source ◽  
Ion Microprobe ◽  
Emission Pattern ◽  
Intrinsic Resolution ◽  
Resolution Imaging ◽  
20 Nm ◽  
Secondary Ion

We have shown the feasibility of 20 nm lateral resolution in both topographic and elemental imaging using probes of this size from a liquid metal ion source (LMIS) scanning ion microprobe (SIM). This performance, which approaches the intrinsic resolution limits of secondary ion mass spectrometry (SIMS), was attained by limiting the size of the beam defining aperture (5μm) to subtend a semiangle at the source of 0.16 mr. The ensuing probe current, in our chromatic-aberration limited optical system, was 1.6 pA with Ga+ or In+ sources. Although unique applications of such low current probes have been demonstrated,) the stringent alignment requirements which they imposed made their routine use impractical. For instance, the occasional tendency of the LMIS to shift its emission pattern caused severe misalignment problems.

Scanning ion microscopy images

1987 ◽  
Vol 45 ◽  
pp. 180-181
Author(s):  
R. Levi-Setti ◽  
J.M. Chabala ◽  
Y.L. Wang
Keyword(s):  
Metal Ion ◽  
Secondary Emission ◽  
Scanning Method ◽  
Ion Channeling ◽  
Secondary Ions ◽  
High Resolution Images ◽  
Ion Microscopy ◽  
Z Contrast ◽  
Focused Beams ◽  
Microscopy Images

Finely focused beams extracted from liquid metal ion sources (LMIS) provide a wealth of secondary signals which can be exploited to create high resolution images by the scanning method. The images of scanning ion microscopy (SIM) encompass a variety of contrast mechanisms which we classify into two broad categories: a) Emission contrast and b) Analytical contrast.Emission contrast refers to those mechanisms inherent to the emission of secondaries by solids under ion bombardment. The contrast-carrying signals consist of ion-induced secondary electrons (ISE) and secondary ions (ISI). Both signals exhibit i) topographic emission contrast due to the existence of differential geometric emission and collection effects, ii) crystallographic emission contrast, due to primary ion channeling phenomena and differential oxidation of crystalline surfaces, iii) chemical emission or Z-contrast, related to the dependence of the secondary emission yields on the Z and surface chemical state of the target.

Freeze-etch TEM of aqueous polymer gel network morphology

1986 ◽  
Vol 44 ◽  
pp. 796-797
Author(s):  
J. A. N. Zasadzinski ◽  
R. K. Prud'homme
Keyword(s):  
Metal Ion ◽  
Polymer Network ◽  
Polymer Gels ◽  
Polymer Gel ◽  
Deformation History ◽  
Crosslinked Polymer ◽  
Aqueous Polymer ◽  
History Of ◽  
Gel Network ◽  
Network Morphology

The rheological and mechanical properties of crosslinked polymer gels arise from the structure of the gel network. In turn, the structure of the gel network results from: thermodynamically determined interactions between the polymer chain segments, the interactions of the crosslinking metal ion with the polymer, and the deformation history of the network. Interpretations of mechanical and rheological measurements on polymer gels invariably begin with a conceptual model of,the microstructure of the gel network derived from polymer kinetic theory. In the present work, we use freeze-etch replication TEM to image the polymer network morphology of titanium crosslinked hydroxypropyl guars in an attempt to directly relate macroscopic phenomena with network structure.

Structures of c-di-GMP/cGAMP degrading phosphodiesterase VcEAL: identification of a novel conformational switch and its implication

2019 ◽  
Vol 476 (21) ◽  
pp. 3333-3353 ◽  
Author(s):  
Malti Yadav ◽  
Kamalendu Pal ◽  
Udayaditya Sen
Keyword(s):  
Active Site ◽  
Metal Binding ◽  
Metal Ion ◽  
Triosephosphate Isomerase ◽  
Catalytic Mechanism ◽  
Degradation Mechanism ◽  
Structural Basis ◽  
Conserved Residues ◽  
Phosphodiester Bond ◽  
Cyclic Dinucleotides

Cyclic dinucleotides (CDNs) have emerged as the central molecules that aid bacteria to adapt and thrive in changing environmental conditions. Therefore, tight regulation of intracellular CDN concentration by counteracting the action of dinucleotide cyclases and phosphodiesterases (PDEs) is critical. Here, we demonstrate that a putative stand-alone EAL domain PDE from Vibrio cholerae (VcEAL) is capable to degrade both the second messenger c-di-GMP and hybrid 3′3′-cyclic GMP–AMP (cGAMP). To unveil their degradation mechanism, we have determined high-resolution crystal structures of VcEAL with Ca2+, c-di-GMP-Ca2+, 5′-pGpG-Ca2+ and cGAMP-Ca2+, the latter provides the first structural basis of cGAMP hydrolysis. Structural studies reveal a typical triosephosphate isomerase barrel-fold with substrate c-di-GMP/cGAMP bound in an extended conformation. Highly conserved residues specifically bind the guanine base of c-di-GMP/cGAMP in the G2 site while the semi-conserved nature of residues at the G1 site could act as a specificity determinant. Two metal ions, co-ordinated with six stubbornly conserved residues and two non-bridging scissile phosphate oxygens of c-di-GMP/cGAMP, activate a water molecule for an in-line attack on the phosphodiester bond, supporting two-metal ion-based catalytic mechanism. PDE activity and biofilm assays of several prudently designed mutants collectively demonstrate that VcEAL active site is charge and size optimized. Intriguingly, in VcEAL-5′-pGpG-Ca2+ structure, β5–α5 loop adopts a novel conformation that along with conserved E131 creates a new metal-binding site. This novel conformation along with several subtle changes in the active site designate VcEAL-5′-pGpG-Ca2+ structure quite different from other 5′-pGpG bound structures reported earlier.

Contribution of MR imaging and CEA cystic fluid level to the differential diagnosis of cystic lesions of the pancreas

2001 ◽  
Vol 120 (5) ◽  
pp. A764-A764
Author(s):  
M DELHAYE ◽  
C WINANT ◽  
D DEGRE ◽  
B GULBIS ◽  
C GERVY ◽  
...  
Keyword(s):  
Differential Diagnosis ◽  
Mr Imaging ◽  
Cystic Lesions ◽  
Fluid Level ◽  
Cystic Fluid
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