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Protein profiling analysis based on matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry and its application in typing Streptomyces isolates
摘要： Marine Streptomyces is a potential source of novel bioactive natural products in medicine and agriculture. The current discrimination and screening method of Streptomyces isolates is not accurate and time-consuming, and a novel method is necessary. In this study, a protein profiling method based on an ultrahigh resolution 15 Tesla Matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance mass spectrometry (MALDI-FTICR MS) was established and applied for differentiation and bioactivity screening of marine Streptomyces isolates. To obtain robust protein profiling, the effects of the protein extraction method, the matrix-solvent, the sample deposition mode, and the culture time of isolates on protein profiling were thoroughly studied, the optimal conditions were obtained. To evaluate the performance of the developed MALDI-FTICR MS method, MALDI-time of flight (TOF) MS and 16S rRNA were applied in parallel to analyze 25 marine Streptomyces isolates. We found that the clustering result of MALDI-FTICR MS was more similar to that of 16S rRNA than MALDI-TOF MS. And MALDI-FTICR MS could effectively indicate the antibacterial activity of Streptomyces isolates against three plant pathogenic bacteria including Xanthomonas campestris, Xanthomonas oryzae and Erwinia carotovora. Furthermore, a differential protein/peptide was defined and successfully applied to predict antibacterial activity of blind samples. This study demonstrated that MALDI-FTICR MS has great potential to discriminate and screen complex microorganisms, especially those closely related strains.
关键词： Protein profiling,Streptomyces isolates,Cluster analysis,Activity screening,Matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry
更新于2025-09-16 10:30:52
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2125. Staphylococcus Species Identification by Fourier Transform Infrared (FTIR) Spectroscopic Techniques: A Cross-Lab Study
摘要： Staphylococcus aureus is well known to be associated with atopic dermatitis. Recent studies also report S. aureus presence in lesional skin of squamous cell carcinoma (SCC) and its precursor lesion, actinic keratosis (AK). Therefore, it is of potential clinical interest to monitor skin S. aureus colonization on AK lesions. Fourier transform infrared (FTIR) spectroscopy is a cost-effective, nondestructive, and reagent-free technique for rapid microbial identification. It is based on the use of spectral databases developed with well-characterized strains in conjunction with the application of multivariate statistical analysis to elaborate classification models. In the present cross-lab study, spectral databases containing FTIR spectra of over 1000 staphylococcal isolates obtained from reference and clinical microbiology laboratories across Canada were employed in the FTIR spectroscopic identification of Staphylococcus spp. isolated from AK, SCC and perilesional skin of patients at the Princess Alexandra Hospital Dermatology Clinic in Brisbane, Australia.
关键词： atopic dermatitis,actinic keratosis,squamous cell carcinoma,microbial identification,Staphylococcus aureus,Fourier transform infrared spectroscopy
更新于2025-09-16 10:30:52
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Sensitivity-Enhanced Fourier Transform Mid-Infrared Spectroscopy Using a Supercontinuum Laser Source
摘要： Fourier transform infrared (FT-IR) spectrometers have been the dominant technology in the field of mid-infrared (mid-IR) spectroscopy for decades. Supercontinuum laser sources operating in the mid-IR spectral region now offer the potential to enrich the field of FT-IR spectroscopy due to their distinctive properties, such as high-brightness, broadband spectral coverage and enhanced stability. In our contribution, we introduce this advanced light source as a replacement for conventional thermal emitters. Furthermore, an approach to efficient coupling of pulsed mid-IR supercontinuum sources to FT-IR spectrometers is proposed and considered in detail. The experimental part is devoted to pulse-to-pulse energy fluctuations of the applied supercontinuum laser, performance of the system, as well as the noise and long-term stability. Comparative measurements performed with a conventional FT-IR instrument equipped with a thermal emitter illustrate that similar noise levels can be achieved with the supercontinuum-based system. The analytical performance of the supercontinuum-based FT-IR spectrometer was tested for a concentration series of aqueous formaldehyde solutions in a liquid flow cell (500 mm path length) and compared with the conventional FT-IR (130 mm path length). The results show a four-times-enhanced detection limit due to the extended path length enabled by the high brightness of the laser. In conclusion, FT-IR spectrometers equipped with novel broadband mid-IR supercontinuum lasers could outperform traditional systems providing superior performance, e.g., interaction path lengths formerly unattainable, while maintaining low noise levels known from highly stable thermal emitters.
关键词： Mid-infrared spectroscopy,mid-IR,supercontinuum laser source,Fourier transform infrared spectroscopy,FT-IR
更新于2025-09-16 10:30:52
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Direct Observation of Intracavity Pulse Dynamics in All-Normal Dispersion All-Fiber Oscillator
摘要： Ultrafast science and technology depend strongly on the development of novel ultrafast sources, thus good understanding of nonlinear phenomena in such systems is of essence. In this paper, we present the experimental observation and theoretical analysis of various pulse dynamics in all-normal dispersion cavity producing dissipative soliton pulses. We report the results of an extensive study regarding the Stimulated Raman Scattering (SRS) process, which creates a main upper limitation for the pulse energy achievable from all-normal dispersion fiber oscillators. We report the measurements of real-time, single shot spectra registered using Dispersive Fourier Transform (DFT) technique together with measured averaged spectral phase of the pulses generated from an all-PM-fiber oscillator mode-locked with Nonlinear Optical Loop Mirror (NOLM). It is found that NOLM parameters directly influenced the pulse stability and dynamics. The Yb-doped fiber was used as an active medium and Dissipative Soliton (DS) pulses centered at 1030 nm were generated together with Stokes radiation shifted by 440 cm-1 (centered approximately at 1078 nm) produced in SRS process. The light generated in SRS process was suppressed from round-trip to round-trip by a narrow pass-band spectral filter centered at 1030 nm placed inside the laser cavity. We present the broad experimental study of ultrashort pulse dynamics with strong presence of SRS process. Spectral intensity correlation maps were calculated to describe how the SRS process disturbs the ultrashort pulse during propagation in the cavity (Fig. 1). The intensities of longer wavelengths (1040 – 1050 nm) in the pulse spectrum were destabilized due to the SRS process. In normal dispersion fiber Stokes SRS components have higher group velocity than the pulse spectral components. For positively chirped pulse SRS affects only the leading edge of the pulse which is manifested as negative correlation (Fig. 1(c)). The phenomena of repetitive partial dissipative soliton explosions and bistability of the pulse operation in an all-PM-fiber all-normal dispersion oscillator cavity were investigated as well. The clear signature of bistable operation was the hysteresis of the laser pulse power versus input pump power. Furthermore, we registered significant differences between the measured pulses spectral phases for each case. Another set of measurements was performed to analyze the pulse self-starting dynamics. We present the experimental study and numerical simulations of DS pulse dynamics in an all-normal dispersion all-fiber cavity. The numerical simulations were performed using the standard split-step Fourier-transform method employing the multi-vibrational model of SRS. DS lasers are important pulse sources and an effective platform to investigate the pulse dynamics and nonlinear processes inside the all-fiber cavities.
关键词： spectral intensity correlation maps,Yb-doped fiber,dissipative soliton pulses,Dispersive Fourier Transform,split-step Fourier-transform method,Nonlinear Optical Loop Mirror,Stimulated Raman Scattering,ultrafast science
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - A Hyperspectral Microscope Based on a Birefringent Ultrastable Common-Path Interferometer
摘要： Spectral microscopy is a method to acquire the spectrum for each point in the image of a sample. The most straightforward technique uses spectral filters to collect a sequence of images at a discrete number of spectral bands. A more complete spectral characterization is hyperspectral microscopy, which acquires the whole continuous spectrum of each point of the image. A powerful approach to this aim is Fourier-transform (FT) spectrometry [1, 2], in which an optical waveform is split by an interferometer in two delayed replicas, whose interference pattern is measured by a detector as a function of their delay. The FT of the resulting interferogram yields the continuous intensity spectrum of the waveform. The FT approach is able to retrieve in parallel the spectra for all pixels in a scene and is hence suited for wide-field microscopy, but it requires controlling the delay with sub-cycle precision, which is very difficult to achieve with Michelson and Mach-Zehnder interferometers. Here we introduce a hyperspectral microscope based on the FT approach and using a compact, highly stable common-path birefringent interferometer, a version of the Translating-Wedge-based Identical pulses eNcoding System (TWINS) [3, 4]. Figure 1(a) shows the schematic setup of the microscope. Light is collected by an infinity-corrected objective, it propagates in the interferometer and it is imaged on the 2D detector (14-bits, silicon monochrome CMOS camera) by a tube lens. The component P1 polarizes the input light at 45°. A and B are (cid:302)BBO-birefringent blocks with crossed optical axes; block A is shaped in the form of two wedges, so that its total thickness can be changed by translating one of the wedges with a motorized stage. During propagation, the ordinary and extraordinary light projections accumulate a relative delay ranging from positive to negative values according to the relative thickness of A and B. P2 projects the replicas to the same polarization (45°), enabling interference. The spectral resolution of the interferometer is inversely proportional to the adjustable total phase delay. The largest position scan of our interferometer setup introduces a delay of ±250 fs at (cid:540) = 600 nm and corresponds to spectral resolution of 3 THz (~4 nm).
关键词： Fourier-transform spectrometry,TWINS,hyperspectral microscopy,birefringent interferometer
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Dispersive Fourier Transform Based Single-Shot CEP Drift Measurement at Arbitrary Repetition Rate
摘要： In recent years attosecond science motivated the development of laser systems, which provide millijoule energy level few-cycle pulses. These experiments rely on a field with stable amplitude and carrier envelope phase (CEP) to provide reproducible results [1]. As a consequence, diagnostic devices, which are capable of single-shot CEP measurement and pulse tagging, became a must-have equipment in today’s laser systems. The self-referenced interferometry such as f-to-2f [2] are one of the most typical way to characterize the shift of the CEP in a single-shot manner. The highest achievable recording rate is mostly limited by the measurement times of the optical spectroscopes, which can only reach 10 kHz even with fast detector array. Dispersive Fourier Transform (DFT) [3,4] can be used to bypass this limitation, so single-shot recordings of the output signal of an f-to-2f interferometer becomes possible even at high repetition rates. The method depends on an optical element with enough dispersion to stretch to pulse duration up to the nanosecond range. Therefore, the spectral modulation pattern containing the encoded CEP appears in the temporal domain, which allows for tracking with a relatively slow photodetector. To demonstrate the validity and performance of this concept, a CEP drift measurement was performed on the state-of-the-art mid-infrared (MIR) laser system at ELI-ALPS [5], which provides mid-IR laser pulses at 100 kHz. As a comparison, an alternative measurement was performed in parallel with a grating spectrometer (Fringeezz, Fastlite) [6] at 10 kHz sampling rate. The two recorded signals were synchronized and a decimated 10 kHz subset was extracted, where correlation between measurements is the highest. One of the main limitation of the DFT method originates from the time jitter between the output of the laser and the TTL signal used for triggering. This time jitter changes the time delay of the modulation pattern, creating an additional noise source for the measured relative CEP value. In order to perform truly time jitter-free single-shot CEP drift measurement, an additional CEP independent spectral modulation was introduced, which can be used to determine the noise originating from the jitter. The jitter-free decimated dataset against the grating spectrometer measurement is displayed on Fig. 1. The calculated CEP noises are summarized in Table 1. These values agree within the limit of the uncertainty of these measurements, validating that this new CEP drift measurement method is easily scalable to arbitrary repetition rates.
关键词： high repetition rate,mid-infrared laser system,Dispersive Fourier Transform,CEP drift measurement,single-shot
更新于2025-09-12 10:27:22
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Analysis of laser radiation using the Nonlinear Fourier transform
摘要： Modern high-power lasers exhibit a rich diversity of nonlinear dynamics, often featuring nontrivial co-existence of linear dispersive waves and coherent structures. While the classical Fourier method adequately describes extended dispersive waves, the analysis of time-localised and/or non-stationary signals call for more nuanced approaches. Yet, mathematical methods that can be used for simultaneous characterisation of localized and extended fields are not yet well developed. Here, we demonstrate how the Nonlinear Fourier transform (NFT) based on the Zakharov-Shabat spectral problem can be applied as a signal processing tool for representation and analysis of coherent structures embedded into dispersive radiation. We use full-field, real-time experimental measurements of mode-locked pulses to compute the nonlinear pulse spectra. For the classification of lasing regimes, we present the concept of eigenvalue probability distributions. We present two field normalisation approaches, and show the NFT can yield an effective model of the laser radiation under appropriate signal normalisation conditions.
关键词： eigenvalue probability distributions,signal normalisation,Zakharov-Shabat spectral problem,mode-locked pulses,Nonlinear Fourier transform
更新于2025-09-12 10:27:22
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Fourier transforms for fast and quantitative Laser Speckle Imaging
摘要： Laser speckle imaging is a powerful imaging technique that visualizes microscopic motion within turbid materials. At current two methods are widely used to analyze speckle data: one is fast but qualitative, the other quantitative but computationally expensive. We have developed a new processing algorithm based on the fast fourier transform, which converts raw speckle patterns into maps of microscopic motion and is both fast and quantitative, providing a dynamnic spectrum of the material over a frequency range spanning several decades. in this article we show how to apply this algorithm and how to measure a diffusion coefficient with it. We show that this method is quantitative and several orders of magnitude faster than the existing quantitative method. finally we harness the potential of this new approach by constructing a portable laser speckle imaging setup that performs quantitative data processing in real-time on a tablet.
关键词： Fast Fourier Transform,Real-time Analysis,Quantitative Imaging,Laser Speckle Imaging,Microscopic Motion
更新于2025-09-12 10:27:22
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Real-time dynamics of soliton collision in a bound-state soliton fiber laser
摘要： We experimentally investigated the soliton collisions between soliton molecules and deuterogenic solitons spontaneously generated on the continuous wave (cw) noise background in an ultrafast erbium-doped fiber laser mode locked with MoS2 saturable absorber (SA). The dynamics of the soliton collisions were observed using the time-stretch dispersion Fourier transform technique. The noise-induced deuterogenic solitons first undergo spectral broadening and wavelength shifting, then collide successively with a soliton molecule and eventually vanish. Within the simple collision framework, the spectral-temporal dynamics of soliton collision would help to unveil the self-stabilization mechanism of the soliton molecules in consideration of dispersive wave shedding. This nonlinear dynamics is similar to the soliton rain, except that complex condensed soliton phase is substituted with a soliton molecule.
关键词： time-stretch dispersive Fourier transform.,soliton molecule,molybdenum disulfide,soliton collision
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Monolithic and In-Line Method for the Measurement of Time-Dependent Polarization of Ultrashort Pulses
摘要： Many recent applications of vector pulses require the characterization of time-dependent polarization of ultrashort laser pulses. For a precise measurement, the relative phase between the vector components is crucial. We propose a monolithic, in-line, single-channel interferometer setup, which allows the full determination of the time-evolving polarization state of the pulse, retrieving with precision the relative phase thanks to its great stability (~10-3). This is possible due to the use of a birefringent material (3-mm calcite) to delay the x- and y-components of the pulse. A linear polarizer (LP) is used to measure three projections with a spectrometer: 0o and 90o for the spectral amplitude of the x- and y-components, respectively, and 45o for the spectral interferences of the delayed components. By analysing the latter using Fourier-transform filtering, it is possible to retrieve the full relative phase (including constant term). The spectral phase of one component is measured with a standard temporal measurement device. Also, the system needs to be calibrated in amplitude and phase by measuring the same three spectral projections for a pulse linearly polarized at 45o. The polarization state of the vector pulses is characterized both in the spectral and the temporal domains: intensity, ellipticity, azimuth and phase difference.
关键词： Fourier-transform filtering,birefringent material,interferometer,ultrashort pulses,time-dependent polarization
更新于2025-09-12 10:27:22