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LC-MS Supported Studies on the in Vitro Metabolism of both Enantiomers of Flubatine and the in Vivo Metabolism of (+)-[18F]Flubatine—A Positron Emission Tomography Radioligand for Imaging α4β2 Nicotinic Acetylcholine Receptors
摘要： Both enantiomers of [18F]flubatine are promising radioligands for neuroimaging of α4β2 nicotinic acetylcholine receptors (nAChRs) by positron emission tomography (PET). To support clinical studies in patients with early Alzheimer’s disease, a detailed examination of the metabolism in vitro and in vivo has been performed. (+)- and (?)-flubatine, respectively, were incubated with liver microsomes from mouse and human in the presence of NADPH (β-nicotinamide adenine dinucleotide 2′-phosphate reduced tetrasodium salt). Phase I in vitro metabolites were detected and their structures elucidated by LC-MS/MS (liquid chromatography-tandem mass spectrometry). Selected metabolite candidates were synthesized and investigated for structural confirmation. Besides a high level of in vitro stability, the microsomal incubations revealed some species differences as well as enantiomer discrimination with regard to the formation of monohydroxylated products, which was identified as the main metabolic pathway in this assay. Furthermore, after injection of 250 MBq (+)-[18F]flubatine (specific activity > 350 GBq/μmol) into mouse, samples were prepared from brain, liver, plasma, and urine after 30 min and investigated by radio-HPLC (high performance liquid chromatography with radioactivity detection). For structure elucidation of the radiometabolites of (+)-[18F]flubatine formed in vivo, identical chromatographic conditions were applied to LC-MS/MS and radio-HPLC to compare samples obtained in vitro and in vivo. By this correlation approach, we assigned three of four main in vivo radiometabolites to products that are exclusively C- or N-hydroxylated at the azabicyclic ring system of the parent molecule.
关键词： epibatidine,liquid chromatography-mass spectrometry (LC-MS),flubatine,NCFHEB,liver microsomes,nicotinic acetylcholine receptors (nAChRs),radiometabolites,positron emission tomography (PET)
更新于2025-09-04 15:30:14
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Dynamics of the Geometric Measure of Quantum Discord and Bell Non-Locality in a Ring Cavity Induced by Spontaneous Emission
摘要： By virture of taking into account the two atoms’ spatial motion, we evaluate the dynamics of geometric measure of quantum discord(GMQD) and Bell nonlocality of a two-qubit system in an ideal single-mode ring cavity for two types of extended Werner-like(EWL) internal states. It is shown that both Bell nonlocality and GMQD are closely related to the initial entanglement parameter, the initial state’s purity and the wave packet’s width. We also find that, for the initial state W′ ±, the sudden disappearance and sudden regeneration of GMQD and Bell nonlocality both happen, while for the initial state W±, the phenomena of sudden disappearance and sudden regeneration of Bell nonlocality still exist, but that of GMQD does not occur, that is, GMQD decays to zero asymptotically as time goes on. What’s more, we have proved that the preservation of GMQD is much longer than that of Bell-inequality violation.
关键词： Bell nonlocality,Entanglement,The geometric measure of quantum discord (GMQD),Spontaneous emission
更新于2025-09-04 15:30:14
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Bis[1]benzothieno[1,4]thiazines - Planarity, Enhanced Redox Activity and Luminescence by Thieno-Expansion of Phenothiazine
摘要： Twofold Buchwald-Hartwig aminations selectively furnish all three regioisomers of bis[1]benzothieno[1,4]thiazines and X-ray structure analyses and DFT calculations were corroborated for correlation of their electronic properties. All regioisomers outscore the parent compound phenothiazine with respect to a low lying oxidation potential and reversible redox activity. The anti-anti bis[1]benzothieno[3,2-b:2',3'-e][1,4]thiazines possess lowest oxidation potentials in this series and display pronounced green luminescence in solution (?F ≈ 20%) and in the solid state. Syn-anti regioisomers are only weakly luminescent in solution, but show aggregation induced emission enhancement and solid state luminescence. Most interestingly, found by X-ray structure analyses anti-anti derivatives reveal an amazingly coplanar structure of the pentacyclic anellated 1,4-thiazine system, emphasizing a structural similarity to heteroacenes. The calculated theoretical nucleus-independent chemical shifts additionally suggest that the 8?-electron core systems can be considered as first electronically unbiased anellated 1,4-thiazines with antiaromatic character.
关键词： Heterocycles,1,4-Thiazines,Fluorescence,Buchwald-Hartwig coupling,Cyclic voltammetry,Absorption,Antiaromaticity,Aggregation induced emission enhancement,Polymorphism,DFT calculations
更新于2025-09-04 15:30:14
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A new High-Resolution Imaging System (HiRIS2) detector for preclinical SPECT imaging
摘要： The aim of the work is to describe a new high-performance scintigraphic detector, derived from our previous work based on a Position Sensitive Photomultiplier Tube (PSPMT) with 256 output anodes. This detector is suitable for direct integration into multi-modality imaging systems. Indeed, the detector has been developed in order to be integrated into a pre-clinical system. The detector is based on an H9500 Hamamatsu PSPMT coupled to an LYSO pixelated scintillator and a low-energy tungsten collimator with parallel square holes. In order to limit the overall size of the device, a dedicated compact electronics has been developed. The device design was performed using Monte Carlo transport calculations to aid the development. Our results show a detector performance suitable for application on small animals. The intrinsic spatial resolution was experimentally determined to be about 1.6 mm. The measured energy resolution was ～16% at 140 keV and the maximum recorded sensitivity was ～76 cps/MBq. In addition, the results agree quite well with those of Monte Carlo simulations. We have successfully improved the performance of our previous detector design in order to integrate the new device into a complex system focused on pre-clinical imaging.
关键词： Position sensitive photomultiplier tube,GATE,Scintigraphic small animal imaging,Single photon emission,SPECT
更新于2025-09-04 15:30:14
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Terahertz Superconducting Radiometric Spectrometer in Tibet for Atmospheric Science
摘要： Terahertz superconducting radiometric spectrometer (TSRS), as one of seven instruments of the atmospheric profiling synthetic observation system (APSOS) project, was completed in the middle of 2017 after 5 years of development. It is a dual-band heterodyne receiver system based on high sensitive superconductor-insulator-superconductor (SIS) mixers which cover the frequency range of 180 to 380 GHz. With fast Fourier transform spectrometer (FFTS) of each band, real-time observation of 2 GHz bandwidth of high spectral resolution atmospheric molecular emission lines has been demonstrated. TSRS has been deployed at Yangbajing site, which stands on the Qinghai-Tibet Plateau at an altitude of 4300 m in southwestern China, since October 2017. It has been worked in a preliminary observation phase along with other active observation equipment of APSOS. Since then, ozone emission lines around 236 GHz and 358 GHz have been monitored simultaneously. Achieved data will be used to retrieve the in situ vertical distribution of ozone and its movement among different layers of the atmosphere.
关键词： Heterodyne receiver,Terahertz,Molecular emission lines,Superconducting
更新于2025-09-04 15:30:14
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AIEgen Nanoparticles of Arylamino Fumaronitrile Derivative with High Near-infrared emission for Two-photon Imaging and in vivo Cell Tracking
摘要： Developing of two-photon materials for live-cell imaging and in vivo analysis in-deep have been received great attention, and it is still urgent so that such microscopy technique could be promoted and advanced into new progress using the powerful probs. Herein, a new arylamino fumaronitrile derivative NPAPF was synthesized and transferred as aggregation-induced emission luminogen (AIEgen) fluorescent nanoparticles (AF-NPs) via assembly technique. This AF-NPs exhibited two-photon absorption cross-section at 2.6×106 GM with 19.5% of fluorescence quantum yield. Moreover, utilizing the great potential of AF-NPs, two-photon imaging of live cells with good cytocompatibility is realized upon two-photon microscopy. By in vivo long-term tracing studies of mesenchymal stem cells, we demonstrated the tremendous advantage of AF-NPs tracer in monitoring the stem cells transplant. Therefore, our unique AF-NPs provided an efficient two-photon-absorbing probe for investigating biological mechanism and behavior, and also opened a new avenue for spatiotemporal visualization of transplanted stem cells.
关键词： organic nanoparticles,aggregation-induced emission,two-photon,in vivo imaging,mesenchymal stem cell
更新于2025-09-04 15:30:14
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Synthesis and evaluation of 4-(2-fluoro-4-[11C]methoxyphenyl)-5-((2-methylpyridin-4-yl)methoxy)picolinamide for PET imaging of the metabotropic glutamate receptor 2 in the rat brain
摘要： Metabotropic glutamate receptor 2 (mGluR2) has been suggested as a therapeutic target for treating schizophrenia-like symptoms arising from increased glutamate transmission in the human forebrain. However, no reliable positron emission tomography (PET) radiotracer allowing for in vivo visualization of mGluR2 in the human brain is currently available. In this study, we synthesized 4-(2-fluoro-4-[11C]methoxyphenyl)-5-((2-methylpyridin-4-yl)methoxy)picolinamide ([11C]1) and evaluated its potential as a PET tracer for imaging mGluR2 in the rodent brain. Compound 1, a negative allosteric modulator (NAM) of mGluR2, showed high in vitro binding affinity (IC50: 26 nM) for mGluR2 overexpressed in human cells. [11C]1 was synthesized by O-[11C]methylation of the phenol precursor 2 with [11C]methyl iodide. After the reaction, HPLC purification and formulation, [11C]1 of 7.4 ± 2.8 GBq (n = 8) was obtained from [11C]carbon dioxide of 22.5 ± 4.8 GBq (n = 8) with >99% radiochemical purity and 70 ± 32 GBq/μmol (n = 8) molar activity at the end of synthesis. In vitro autoradiography for rat brains showed that [11C]1 binding was heterogeneously distributed in the cerebral cortex, striatum, hippocampus, and cerebellum. This pattern is consistent with the regional distribution pattern of mGluR2 in the rodent brain. The radioactivity was significantly reduced by self- or MNI-137 (a mGluR2 NAM) blocking. Small-animal PET studies indicated a low in vivo specific binding of [11C]1 in the rat brain. The brain uptake was increased in a P-glycoprotein and breast cancer resistant protein double knockout mouse, when compared to a wild-type mouse. While [11C]1 presented limited potential as an in vivo PET tracer for mGluR2, we suggested that it can be used as a lead compound for developing new radiotracers with improved in vivo brain properties.
关键词： positron emission tomography,radiotracer,schizophrenia,metabotropic glutamate receptor 2,in vitro autoradiography
更新于2025-09-04 15:30:14
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Luminescence properties of Tb <sup>3+</sup> doped Gd <sub/>2</sub> (WO <sub/>4</sub> ) <sub/>3</sub> phosphor prepared by hydrothermal method
摘要： The Gd2(WO4)3:Tb3+ phosphors have been successfully prepared using the hydrothermal method calcined at 900℃ in this work. The crystal structure, PLE/PL and fluorescence decay behavior of samples were investigated in detail. Under the 270 nm excitation (4f8→4f75d1 transition of Tb3+), the (Gd2-xTbx)(WO4)3 (x=0.01-0.15) phosphors emit the strong green emission at 547 nm (5D4→7F5 transition of Tb3+). The quenching concentration was found to be ~10% owing to the exchange reaction between Tb3+. The Tb3+ addition did not influence the CIE chromaticity coordinates (~0.33±0.02, ~0.60±0.02) and color temperatures (~5542 K) of the (Gd2-xTbx)(WO4)3 phosphors. However, due to the energy transfer between Tb3+, the fluorescence lifetime for 547 nm emission decreased with the Tb3+ content increasing. The Gd2(WO4)3:Tb3+ phosphors with strong green emission are expected to be widely used in white light LED and display areas.
关键词： Tb3+ doped,Gd2(WO4)3 phosphor,hydrothermal method,Luminescence,green emission
更新于2025-09-04 15:30:14
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Near-ultraviolet excited Tm3+ and Dy3+ ions co-doped barium lanthanum silica oxide phosphors for white-light applications
摘要： Nowadays, trivalent rare-earth ions activated inorganic luminescent materials have been widely investigated owing to their important applications in solid-state lighting field. Tm3+ and Dy3+ ions single- or co-doped Ba3La6(SiO4)6 (BLSO) phosphor materials for white light application were synthesized by a citrate-based sol-gel method. The prepared samples were examined by X-ray diffraction (XRD), scanning electron microscopy and Fourier-transform infrared spectroscopy to analyze the phase purity, surface morphology and existence of functional groups, respectively. The XRD pattern confirmed that the BLSO host lattice exhibited a hexagonal crystal structure with P63/m (176) space group, which is well indexed with standard JCPDS data. From photoluminescence results, the BLSO:Tm3+ phosphors exhibited purplish blue emission at 453 nm (1D2/3F4) and the BLSO:Dy3+ phosphors showed predominant yellow emission at 575 nm (4F9/2 / 6H13/2) compared to their shoulder blue emission at 479 nm (4F9/2 / 6H15/2), indicating that the Dy3+ ions occupied lattice sites with low inversion symmetry. The determined Commission Internationale de I’Eclairage (CIE) (0.3391, 0.3302) values for the Tm3+ and Dy3+ co-doped BLSO phosphors were near to the standard sun light CIE values (0.33, 0.33) under near-ultraviolet (364 nm) excitation. The energy transfer process from Dy3+ to Tm3+ ions was discussed and it was proved by their corresponding decay curves. Additionally, thermal study was carried out for the optimized phosphor and it maintained superior thermal PL properties.
关键词： Citrate-based sol-gel technique,Ba3La6(SiO4)6 phosphors,Pure white emission,Thermal stability
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA) - Singapore (2018.7.16-2018.7.19)] 2018 IEEE International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA) - Characterization of Bandgap Engineering on Operative Transistor Devices by Spectral Photon Emission
摘要： In modern IC technologies, it is very common to use germanium enriched silicon in order to increase field effect transistor (FET) channel carrier mobility for high performance. The germanium content modifies the effective semiconductor band gap EG. Thus, the bandgap energy EG is an important technology performance parameter. EG can be obtained in an LED-like operation of electronic devices, requiring forward biased p-n junctions. P-n junctions in FETs are source or drain to body diodes, usually grounded or reversely biased. This investigation applies a bias to the body that can trigger parasitic forward operation of the source/drain to body p-n junction in any FET. Spectral photon emission (SPE) is taken here as non-destructive in operative method to characterize engineered bandgaps transistor devices, while the device remains fully functional. Proving this technique with the nominal silicon bandgap on an (unstrained) 120nm technology FET, the characterization capability for bandgap engineering is successfully demonstrated using SiGe:C HBT. In IC technology, Ge enriched silicon is recently often used to increase channel carrier mobility. As a next step, 14/16nm p-type FinFET devices have been investigated by applying a bias voltage to the body and thereby activating one of the body/diffusion p-n junctions in forward bias. By measuring the spectral distribution of emission intensity through the backside of the operating device with an InGaAs detector, EG of the engineered bandgap can be determined in the FinFETs as well, in case of the investigated p-type FinFETs to 0.84 eV. This opens a new path for contactless fault isolation by quantitative local determination of bandgap engineering.
关键词： Bandgap engineering,body diode,heterojunction bipolar transistor,body bias voltage,contactless fault isolation,parasitic operation,FinFET,germanium,MOSFET,p-n junction,bandgap characterization,spectral photon emission,SiGe,HBT
更新于2025-09-04 15:30:14