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[Methods in Molecular Biology] Prenatal Diagnosis Volume 1885 || Rapid Prenatal Aneuploidy Screening by Fluorescence In Situ Hybridization (FISH)
摘要： The most common aneuploidies observed in prenatal diagnostics in the second trimester are trisomies of the chromosomes 13, 18 or 21 and gonosomal abnormalities. Rapid detection of these aneuploidies after amniocentesis is possible by ?uorescence in situ hybridization (FISH) utilizing centromeric or locus-speci?c probes. FISH aneuploidy screening results in uncultured amniocytes are available within 24 h or less. Operators should be aware that there are possible pitfalls in connection with the commercially available probe sets and in result interpretation in general and thus proceed with appropriate caution. Here, we explain how rapid prenatal aneuploidy screening is performed using the Food and Drug Administration (FDA-) approved Aneu Vysion kit (ABBOTT/Vysis) and a review is given of drawbacks and opportunities of the method.
关键词： Molecular cytogenetics,Prenatal diagnosis,Interphase FISH,Fluorescence in situ hybridization (FISH),Pitfalls
更新于2025-09-10 09:29:36
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Molecular Diagnostics in Cytopathology (A Practical Handbook for the Practicing Pathologist) || Fluorescence In Situ Hybridization (FISH) Testing in Urinary Tract Cytology
摘要： Fluorescence in situ hybridization (FISH) allows for visualization of specific DNA sequences and can, therefore, be used for quantitation of chromosomes and genes, including aneusomies, chromosomal deletions, or amplifications. The commercial assay UroVysion? (Vysis, Inc., Downers Grove, IL, USA) has made the FISH technique available for routine use in hospital cytology laboratories, but most UroVysion? tests are performed at large reference laboratories. The UroVysion? assay is composed of four single-stranded fluorescently labeled nucleic acid probes – three chromosome enumeration probes (CEP) for the chromosomes 3, 7, and 17 and the single locus-specific identifier (LSI) probe 9p21. The DNA probes are directly labeled with the four different fluorescent dyes SpectrumRed (CEP3), SpectrumGreen (CEP7), SpectrumAqua (CEP17), and SpectrumGold (LSI 9p21).
关键词： UroVysion?,locus-specific identifier,Fluorescence in situ hybridization,urothelial carcinoma,urinary cytology,FISH,chromosome enumeration probes
更新于2025-09-10 09:29:36
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Real-time observation of the temperature-induced phase transformation in GeTe and its thermal expansion properties
摘要： The GeTe-based system has long been considered as a promising candidate system for various functional applications; many of which are directly related to the polymorphic phase transformation in their crystalline forms. Consequently, the microstructure underlying their intriguing phase transition has been the subject of numerous studies. Here we provide real-time observation of the microstructural changes associated with the reversible pseudo-cubic (or rhombohedral) to cubic GeTe phase transition using high-voltage transmission electron microscopy (HV-TEM) operating at 1,250kV and complementary high-temperature X-ray diffraction (XRD). As a result of the phase transition, the pseudo-cubic GeTe domain’s configuration significantly changes from its original band-like to a spike-like morphology with a different orientation after a heating/cooling cycle. The coefficients of thermal expansion (CTE) properties as a function of temperature are also explored in relation to the GeTe phase transition.
关键词： CTE ellipsoids,in-situ high voltage transmission electron microscopy,GeTe,thermal expansion tensor,ferroelectric domains
更新于2025-09-10 09:29:36
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Redox Dynamics of Pd Supported on CeO <sub/>2</sub> -ZrO <sub/>2</sub> during Oxygen Storage/Release Cycles Analyzed by Time-Resolved <i>In Situ</i> Reflectance Spectroscopy
摘要： In situ time-resolved diffuse reflectance spectroscopy provided the redox dynamics of Pd nanoparticles supported on an oxygen storage material CeO2-ZrO2 (CZ) under lean/rich perturbation conditions. Because the reflectance at 450 nm is sensitive to the Pd oxidation state but is not affected by the redox of Ce3+/Ce4+ species of CZ, the real-time Pd redox can be monitored every second during oxygen storage/release in simulated engine combustion exhaust gas (CO–C3H6–NO–O2) corresponding to gasoline air-to-fuel ratios of 14.1 (rich) and 15.0 (lean). Although a large amount of O2 was stored by CZ upon the rich-to-lean switch, the rate of Pd oxidation during this event was found to be much more moderate compared to that with a reference catalyst, Pd/Al2O3. Because rapid oxygen uptake by CZ reduces the local O2 partial pressure near the surface, the oxidation of Pd should be retarded. This can preserve active metallic Pd and thus contribute to longer retention of high NO reduction efficiency even under the lean condition. However, the reduction of Pd oxide (PdO) upon reverse (lean-to-rich) switching occurred at a similar rate irrespective of the support material. The metallic Pd deposits near the interface with CZ promote the catalytic activation of reducing gases (CO and C3H6), resulting in significant oxygen release from CZ. The temperature dependence of the redox rate demonstrates that oxidation of metallic Pd to PdO is much slower than reduction over Pd/CZ, whereas oxidation is faster than reduction over Pd/Al2O3. The preservation of active metallic Pd under lean/rich perturbation conditions is another key role of the oxygen storage CZ co-catalyst.
关键词： CeO2-ZrO2,in situ diffuse reflectance spectroscopy,oxygen storage/release,redox dynamics,Pd nanoparticles
更新于2025-09-10 09:29:36
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Synthesis and characterization of Al-Fe-Cu tri-doped TiO <sub/>2</sub> by in-situ hydrothermal for degradation of methylene blue dyes
摘要： Pure TiO2 and a series of Al-Fe-Cu tri-doped TiO2 were synthesized by using in-situ hydrothermal method. The synthesized materials were characterized using X-ray diffraction (XRD), Fourier Transform Infrared (FTIR) and Scanning Electron Microscope (SEM). The photocatalytic activity of the samples was evaluated for degradation of methylene blue (5mgL-1) in aqueous solution under uv-visible light (λ= <420 nm). The XRD pattern showed that all samples exhibited anatase phase after calcined at temperature 500°C with crystallite size in the range of 10.00-13.23 nm. The FTIR spectra showed three important vibrational modes for vOH, δOH and vTiO that were assigned at range 3411.75-3399.27 cm-1, 1626.91-1630.53 cm-1 and 503.30- 530.93 cm-1, respectively. The degradation rate of Al(1mmol)-Fe-Cu tri-doped TiO2 showed the highest photocatalytic degradation with 93% compared to pure TiO2, Al(2 mmol)-Fe-Cu tri-doped TiO2 and Al(3mmol)-Fe-Cu tri-doped TiO2 were calculated as 76%, 85% and 80%, respectively. Hence, it can be seen that, the amount of Al ion-doping have influence on the photocatalytic degradation.
关键词： Al-Fe-Cu tri-doped TiO2,methylene blue,photocatalytic degradation,in-situ hydrothermal
更新于2025-09-10 09:29:36
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An Optical Microreactor Enabling In Situ Spectroscopy Combined with Fast Gas-Liquid Mass Transfer
摘要： A liquid core waveguide membrane microreactor combining intense light matter interaction for in situ sensing and/or photo activation and excellent gas-liquid mass transfer is presented. Basis is a liquid-filled Teflon AF tube, which provides light transmission within the liquid core and gas permeation through the wall. The study shows that a wide spectral range (UV-vis) with relatively low optical losses is accessible. A working regime preventing gas bubble formation was deduced for semi-batch and in flow operation for gas pressures up to 8 bar. Residence time distribution experiments revealed Bodenstein numbers from 21 to 60 in the studied flow range. As example, the methylene blue catalyzed oxidation of D-glucose by O2 was studied at different pressures, while methylene blue was monitored in situ.
关键词： Teflon amorphous fluoropolymers,Optical microreactors,In situ spectroscopy,Gas-liquid reactions,Tube-in-tube contactor
更新于2025-09-10 09:29:36
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Temperature Dependent Micro-Structure of KAlF4 from Solid to Molten States
摘要： In situ high temperature X-ray diffraction and Raman spectroscopy were used to investigate the temperature dependent micro-structure of KAlF4. Density functional theory was applied to simulate the structure of crystalline KAlF4 while a quantum chemistry ab initio simulation was performed to explore the structure of molten KAlF4. Two crystal polymorphs demonstrated to be present in solid KAlF4. At the temperature below 673 K, it belongs to the tetragonal crystal system within the P4/mbm space group, while the high temperature phase is attributed to the monoclinic crystal system within the P21/m space group. Both polymorph KAlF4 phases are characterized by a layered structure consisting of K+ and [AlF6]3? octahedra, each of the [AlF6]3? octahedra equivalently shares four corners with other four [AlF6]3? octahedra along the layer. The layered structure became unstable at higher temperatures and crashed when the temperature exceeded the melting point. It demonstrated that the molten KAlF4 consisted of predominant [AlF4]? and a small amount of [AlF6]3?. The Raman spectrum of molten KAlF4 simulated by using a quantum chemistry ab initio method agreed well with the experimental Raman spectrum.
关键词： [AlF6]3? octahedra,in situ,KAlF4,layered structure,[AlF4]? tetrahedra
更新于2025-09-10 09:29:36
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In-Situ imaging detection of cell membrane and intracellular cholesterol via cascade reactions
摘要： Herein, an e?ective membrane-to-intracellular cholesterol detection strategy was designed based on cascade reactions. A biochip array was ?rstly fabricated by consecutively immobilizing luminol modi?ed gold nanoparticles (Au@luminol), soybean peroxidase (SBP) and cholesterol oxidase (ChoX) on the cellulose acetate (CA) membrane functionalized home-made micropore array. When cholesterol existed, it was oxidized by ChoX generating H2O2, which further triggered the CL reaction under the SBP catalysis, the CL signals were collected by a charge-coupled device (CCD). The proposed strategy exhibited a wide linear range from 0.12 μM to 1000 μM and relatively low detection limit (LOD) of 0.08 μM. Furthermore，it could be used to in-situ detect membrane cholesterol and intracelluar esteri?ed cholesterol in HepG2 cells. After activated HepG2 cells were added to the modi?ed biochip, membrane cholesterol was detected directly. Intracelluar esteri?ed cholesterol was detected through the introduction of triton X-100 and cholesteryl esterase (ChoE). Additionally, the cholesterol content in cells was changed after stimulated by drugs, such as apolipoprotein A-I (ApoA-I), pitavastatin or probucol. The correlation of the CL signal with the amount of cholesterol con?rmed that our strategy was feasible to simultaneously detect membrane and intracellular cholesterol at di?erent cellular states. The proposed strategy exhibited excellent sensitivity, selectivity, stability, and reproducibility in a simple, cheap way, which opened a new door for studying clinic treatment of the cholesterol-related diseases.
关键词： CL image,In-situ,Intracelluar cholesterol,Membrane cholesterol
更新于2025-09-10 09:29:36
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In situ Raman spectroscopic evidence for oxygen reduction reaction intermediates at platinum single-crystal surfaces
摘要： Developing an understanding of structure–activity relationships and reaction mechanisms of catalytic processes is critical to the successful design of highly efficient catalysts. As a fundamental reaction in fuel cells, elucidation of the oxygen reduction reaction (ORR) mechanism at Pt(hkl) surfaces has remained a significant challenge for researchers. Here, we employ in situ electrochemical surface-enhanced Raman spectroscopy (SERS) and density functional theory (DFT) calculation techniques to examine the ORR process at Pt(hkl) surfaces. Direct spectroscopic evidence for ORR intermediates indicates that, under acidic conditions, the pathway of ORR at Pt(111) occurs through the formation of HO2*, whereas at Pt(110) and Pt(100) it occurs via the generation of OH*. However, we propose that the pathway of the ORR under alkaline conditions at Pt(hkl) surfaces mainly occurs through the formation of O2?. Notably, these results demonstrate that the SERS technique offers an effective and reliable way for real-time investigation of catalytic processes at atomically flat surfaces not normally amenable to study with Raman spectroscopy.
关键词： density functional theory,in situ Raman spectroscopy,electrochemical surface-enhanced Raman spectroscopy,oxygen reduction reaction,platinum single-crystal surfaces
更新于2025-09-10 09:29:36
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Evolution of the Ligand Shell around Small ZnO Nanoparticles during the Exchange of Acetate by Catechol: A Small Angle Scattering Study
摘要： The core-shell structure of colloids surrounded by ligands is of great importance for their later application as it can significantly alter the chemical and physical properties of the nanoparticles (NPs). A combination of small angle X-ray and neutron scattering (SAXS/SANS) the native solution with additional ex situ measurements (titration-UV) was applied to study the NP/ligand interface of ZnO NPs after functionalization with catechol derivatives. Based on SAXS data, it was found that within the multimodal particle size distribution the fraction of agglomerates is shifted to smaller sizes and nearly disappeared upon the binding of ethyl 3,4-dihydroxybenzoate (CAT) molecules. This is ascribed to improved stabilization at the primary particle level by CAT molecules. By combining the neutron scattering contrast with the input of bound CAT molecules from a previously developed titration-UV method, the heterogeneous composition of the ligand shell became accessible for the first time.
关键词： small angle scattering,quantum dots,in situ analysis,ligand exchange,core-shell
更新于2025-09-10 09:29:36