- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Integration of plasmonic heating and ona??chip temperature sensor for nucleic acid amplification assays
摘要： Nucleic acid tests have been widely used for diagnosis of diseases by detecting the relevant genetic markers that are usually amplified using polymerase chain reaction (PCR). This work reports the use of a plasmonic device as an efficient and low-cost PCR thermocycler to facilitate nucleic acid-based diagnosis. The thermoplasmonic device, consisting of a one-dimensional metal grating, exploited the strong light absorption of plasmonic resonance modes to heat up PCR reagents using a near-infrared laser source. The plasmonic device also integrated a thin-film thermocouple on the metal grating to monitor the sample temperature. The plasmonic thermocycler is capable of performing a PCR amplification cycle in approximately 2.5 minutes. We successfully demonstrated the multiplex and real-time PCR amplifications of the antibiotic resistance genes using the genomic DNAs extracted from Acinetobacter baumannii, Klebsiella pneumonia, Escherichia coli, and Campylobacter.
关键词： polymer chain reaction,thermoplasmonics,thermocycler,nucleic acid-based diagnostics,antibiotic resistance detection,Photothermal effect
更新于2025-09-23 15:19:57
-
iHWG-MOX: A hybrid breath analysis system via the combination of substrate-integrated hollow waveguide infrared spectroscopy with metal oxide gas sensors
摘要： According to its materials and operating parameters, MOX sensors respond to target gases only by a change in sensor resistance with lack in selectivity. By use of IR spectroscopy, highly discriminatory information from samples at a molecular level can be obtained and the selectivity can be enhanced. A low-volume gas-cell was developed for a commercially available semiconducting metal oxide (MOX) methane gas sensor and coupled directly to a mid-infrared gas sensor based on substrate-integrated hollow waveguide (iHWG) technology combined with a Fourier transform infrared spectrometer. This study demonstrates a sensing process with combined orthogonal sensors for fast, time resolved and synergic detection of methane and carbon dioxide in gas samples.
关键词： iHWG,substrate integrated hollow waveguide,eNose,breath diagnostics,breath analysis,metal oxide (MOX) sensor
更新于2025-09-23 15:19:57
-
Immunochromatographic System for Serodiagnostics of Cattle Brucellosis Using Gold Nanoparticles and Signal Amplification with Quantum Dots
摘要： In this article, we describe an immunochromatographic test system developed for rapid serodiagnostics of cattle brucellosis using two markers: Gold nanoparticles (GNPs) and quantum dots (QDs). The test system was compared with immunochromatographic serodiagnostics systems that use only one marker. The approbation of the test system was conducted on samples of cattle sera with low, but diagnostically significant titers of specific antibodies. We show that when two conjugates are used, the intensity of the detectable signal increases by 2–3 times compared with the test system using the QD conjugate and by more than nine times compared with the system using the GNP conjugate.
关键词： signal enhancement,cow diseases,rapid tests,lateral flow tests,functionalized nanoparticles,veterinary diagnostics
更新于2025-09-23 15:19:57
-
Laser Raman scattering by graphene plasmons
摘要： A new scheme of Raman scattering of a laser by THz graphene plasmons in the presence of both space charge and electromagnetic surface plasmons is proposed. Plasmon–laser coupling arises through the two dimensional response of electrons in graphene. For optical frequency laser scattering by THz plasmons, phase matching conditions are satis?ed for near normal incidence and the Raman scattered wave also propagates normal to the graphene surface. The amplitude of the electric ?eld of the Raman scattered wave scales linearly with the plasmon density ?uctuation level and laser amplitude and inversely with the electron effective mass. Raman scattering would provide in situ diagnostics of the amplitude and frequency of the THz wave.
关键词： THz,diagnostics,Raman scattering,graphene plasmons,laser
更新于2025-09-23 15:19:57
-
Time-resolved study of Bremsstrahlung emission and spectra at the early stage in a nanosecond laser ablated tungsten plasma
摘要： Laser-Induced Breakdown Spectroscopy (LIBS) has been considered as a crucial tool In this work, a one- dimensional gas-dynamic numerical model has been optimized to simulate the Bremsstrahlung emission and the spectral lines of W and W+ranging from 180 nm to 450 nm at the early stage of plasma in a nanosecond laser ablation. In the literature, most of the researchers pay more attentions on the spectral lines but the Bremsstrahlung emission (continue background) is neglected. In our study, the relationship between plasma temperature and the continue Bremsstrahlung background is found. The numerical results show that the plasma Bremsstrahlung emission dominated in the early time of laser ablation but exponentially decreases from 10 ns to 160 ns. The intensity of spectral lines of W increase while that of W+ increase ?rstly, then decrease gradually from 10 ns to 160 ns. In addition, a Q-switch Nd:YAG pulsed laser with 8 ns FWHM and 1064 nm wavelength is used to experimentally study the plasma emission processes. The results indicate that the plasma Bremsstrahlung domains during the early stage of laser ablation, which is agreement with numerical prediction. The spatial integrated intensity of Bremsstrahlung, W-atomic line emission and W-ionic line emission were investigated. We hope that the results would provide a good guidance for optimizing LIBS application for PWI diagnosis of fusion devices.
关键词： Plasma generation (laser-produced, RF, x ray-produced),Plasma diagnostics - charged-particle spectroscopy
更新于2025-09-23 15:19:57
-
Diffuse-reflection-based single-ended laser absorption sensor for H2O temperature and concentration in kerosene-fuelled combustor
摘要： The design, optimization and demonstration of a compact, single-ended laser absorption sensor based on diffuse-wall-reflected signal is presented for temperature and H2O concentration measurements in a kerosene-fuelled aero-combustor. Challenges of laser measurements in such harsh, practical combustion environments involve strong beam-steering, low signal-to-noise ratio (SNR), and constrained optical access. We here present detailed characterization and optimization procedure of a single-ended optical configuration using a holed off-axis parabolic mirror as the pitch and catch optics, and the coked wall surface of the combustor as a diffuse reflector. A near-infrared distributed-feedback diode laser near 1.4 μm scanned at 1 kHz for direct absorption detection was used to access two H2O transitions for concentration and temperature measurement. Optical system design and adaptive Savitzky-Golay signal processing algorithm was used for noise suppression and SNR amelioration. The sensor was demonstrated under practical conditions in a kerosene-fuelled swirl combustor. High signal fidelity was achieved and allowed for single-scan H2O concentration detection limit of 122 ppm-m-Hz-1/2 despite a low reflected laser intensity level of ~50 μW. In situ, time-resolved measurements detected temperatures ranging from ~1100 K to 1300 K, and H2O concentration ranging from ~8% to 12% as global equivalence ratio varied between 0.2 and 0.45. The results revealed expected trend while demonstrating much faster response and less delay versus a comparing thermocouple. This successful field manifestation provides direct proof for the robustness and reliability of diffuse-reflection-based single-ended sensor system in engine combustion chamber environments.
关键词： single-ended,turbulent environment,combustion diagnostics,laser absorption sensing,kerosene-fuelled combustor
更新于2025-09-23 15:19:57
-
Debris and shrapnel assessments for National Ignition Facility targets and diagnostics
摘要： High-energy laser experiments at the National Ignition Facility (NIF) can create debris and shrapnel capable of damaging laser optics and diagnostic instruments. The size, composition and location of target components and sacrificial shielding (e.g., disposable debris shields, or diagnostic filters) and the protection they provide is constrained by many factors, including: chamber and diagnostic geometries, experimental goals and material considerations. An assessment of the generation, nature and velocity of shrapnel and debris and their potential threats is necessary prior to fielding targets or diagnostics. These assessments may influence target and shielding design, filter configurations and diagnostic selection. This paper will outline the approach used to manage the debris and shrapnel risk associated with NIF targets and diagnostics and present some aspects of two such cases: the Material Strength Rayleigh-Taylor campaign and the Mono Angle Crystal Spectrometer (MACS).
关键词： diagnostics,shrapnel,debris,National Ignition Facility,targets
更新于2025-09-23 15:19:57
-
Simple, Amplified, and Multiplexed Detection of MicroRNAs Using Time-Gated FRET and Hybridization Chain Reaction
摘要： Hybridization chain reaction (HCR) is a simple and sensitive method for quantifying nucleic acids. Current approaches cannot combine a washing-free sensing format with multiplexed target quantification at low concentrations, which would be highly desirable for detection both in solution and in situ. Here, we demonstrate the implementation of time-gated F?rster resonance energy transfer (TG-FRET) between terbium donors and dye acceptors into HCR for multiplexed quantification of microRNAs (miR-20a and miR-21) and their DNA analogues. HCR-TG-FRET provided washing-free nucleic acid quantification with very low limits of detection down to 240 attomoles (1.7 pM) of microRNA and 123 attomoles (0.88 pM) of DNA. Efficient distinction from very homologous microRNAs demonstrated high target specificity. Multiplexing with a single measurement, a single excitation wavelength, and a single FRET pair allowed for a simultaneous quantification of miR-20a and miR-21 at concentrations between 30 pM and 300 pM from the same sample. HCR-TG-FRET showed similar performance for serum-free and serum-containing samples without the use of RNase inhibitors. Our results present a significant improvement of current HCR approaches regarding simplicity, sensitivity, and multiplexing. The versatile diagnostic performance of HCR-TG-FRET even in challenging biological environments presents an important advantage for advanced nucleic acid biosensing.
关键词： miRNA,mRNA,fluorescence,diagnostics,DNA,biosensing
更新于2025-09-19 17:15:36
-
Planar cutoff probe for measuring the electron density of low-pressure plasmas
摘要： The cutoff probe (CP) is a precise diagnostic technique that measures electron density using two cylindrical probe tips and holders inserted in a low-pressure plasma. However, a recent study has reported that the insertion of the probe tips and holders can perturb the plasma condition and act as a source of error in the measurement of electron density. This study proposes a planar cutoff probe (PCP), which does not have invasive probe tips and holders, to minimize the plasma perturbation during plasma measurement. We embed the PCP on the existing substrate chuck of the plasma chamber instead of inserting an additional probe holder into the chamber. The adjusted conditions for the radii of the probe’s antennas and the gap distance between the two probe antennas are obtained via an electromagnetic simulation. The comparative experiment results show that the inferred electron densities of the optimized PCP are in good agreement with those of the previous CP and within reasonable discrepancies stemming from the differences in measurement positions. We believe that the PCP, which can be embedded in the inner surface of the chamber and measure the electron density during the plasma (wafer) process, would be an alternative technical tool to realize advanced process control of plasma based on non-invasive diagnostic methods.
关键词： planar cutoff probe,plasma diagnostics,microwave probe,non-invasive plasma monitoring
更新于2025-09-19 17:15:36
-
Shaping pulses of radiation detectors into a true Gaussian form
摘要： A digital shaper for conversion of detector pulses with a short leading edge and a long exponential tail into a true Gaussian form is proposed and analysed in this paper. The width of Gaussian pulses can be several times smaller than the rise time of the input pulses, i.e. considerably shorter than the undistorted output pulses provided by standard shapers. The algorithm of the true Gaussian shaper is presented in the paper. The output pulses and noises of the true Gaussian shapers are compared with those of standard shapers for different widths of shaped pulses. The analyses has shown that the true Gaussian shaping can be advantageous for detection of strongly overlapped pulses which appear at high particle fluxes in the detector input.
关键词： Digital signal processing (DSP),Electronic detector readout concepts (solid-state),Solid state detectors,Nuclear instruments and methods for hot plasma diagnostics
更新于2025-09-19 17:15:36