Residual Background Research Articles

Sensitivity Enhancement of Time-Gated Raman Spectroscopy by Reducing Systematic Noise of Residual Fluorescence Background

Sensitivity Enhancement of Time-Gated Raman Spectroscopy by Reducing Systematic Noise of Residual Fluorescence Background

Online Tree-Structure-Constrained RPCA for Background Subtraction of X-ray Coronary Angiography Images

Background and objectiveBackground subtraction of X-ray coronary angiograms (XCA) can significantly improve the diagnosis and treatment of coronary vessel diseases. The XCA background is complex and dynamic due to structures with different intensities and independent motion patterns, making XCA background subtraction challenging. MethodsThe current work proposes an online tree-structure-constrained robust PCA (OTS-RPCA) method to subtract the XCA background. A morphological closing operation is used as a pre-processing step to remove large-scale structures like the spine, chest and diaphragm. In the following, the XCA sequence is decomposed into three different subspaces: low-rank background, residual dynamic background and vascular foreground. A tree-structured norm is introduced and applied to the vascular submatrix to guarantee the vessel spatial coherency. Moreover, the residual dynamic background is separately extracted to remove noise and motion artifacts from the vascular foreground. The proposed algorithm also employs an adaptive regularization coefficient that tracks the vessel area changes in the XCA frames. ResultsThe proposed method is evaluated on two datasets of real clinical and synthetic low-contrast XCA sequences of 38 patients using the global and local contrast-to-noise ratio (CNR) and structural similarity index (SSIM) criteria. For the real XCA dataset, the average values of global CNR, local CNR and SSIM are 6.27, 3.07 and 0.97, while these values over the synthetic low-contrast dataset are obtained as 5.15, 2.69 and 0.94, respectively. The implemented quantitative and qualitative experiments verify the superiority of the proposed method over seven selected state-of-the-art methods in increasing the coronary vessel contrast and preserving the vessel structure. ConclusionsThe proposed OTS-RPCA background subtraction method accurately subtracts backgrounds from XCA images. Our method might provide the basis for reducing the contrast agent dose and the number of needed injections in coronary interventions.

Accurate two-step random phase retrieval approach without pre-filtering based on hyper ellipse fitting

In this work, we propose a hyper ellipse fitting-based high-precision random two-frame phase shifting algorithm to improve the accuracy of phase retrieval. This method includes a process of Gram-Schmidt orthonormalization, followed by a hyper ellipse fitting procedure. The Gram-Schmidt orthonormalization algorithm constructs a quadrature fringe pattern relative to the original fringe pattern. These two quadrature fringe patterns are then fed into the hyper ellipse fitting procedure, which reconstructs the phase map and refines the background light to produce the final accurate phase of interest. Due to the hyper ellipse fitting procedure, the demodulation results are significantly improved in many cases. This method allows us to design a two-shot phase reconstruction algorithm without the need for least squares iteration or pre-filtering, effectively mitigating residual background to the greatest extent. It combines the advantages of both the Gram-Schmidt orthonormalization method and the Lissajous ellipse fitting method, making our hyper ellipse fitting approach a simple, flexible, and accurate phase retrieval algorithm. Experiments show that by using the weighted least squares method and adjusting the weights, this method can prioritize data points with more significant information or higher reliability, ensuring more accurate estimation of the ellipse parameters.

Correction for partial volume averaging in the quantification of radiopaque nanomaterial-embedded resorbable polymers

Resorbable inferior vena cava (IVC) filters require embedded contrast for image-guided placement and integrity monitoring. We calculated correction factors to account for partial volume averaging of thin nanoparticle (NP)-embedded materials, accounting for object and slice thicknesses, background signal, and nanoparticle concentration. We used phantoms containing polycaprolactone disks embedded with bismuth (Bi) or ytterbium (Yb): 0.4- to 1.2-mm-thick disks of 20 mg ml−1 NPs (thickness phantom), 0.4-mm-thick disks of 0–20 mg ml−1 NPs in 2 mg ml−1 iodine (concentration phantom), and 20 mg ml−1 NPs in 0.4-mm-thick disks in 0–10 mg ml−1 iodine (background phantom). Phantoms were scanned on a dual-source CT with 80, 90, 100, and 150 kVp with tin filtration and reconstructed at 1.0- to 1.5-mm slice thickness with a 0.1-mm interval. Following scanning, disks were processed for inductively coupled plasma optical emission spectrometry (ICP-OES) to determine NP concentration. Mean and maximum CT numbers (HU) of all disks were measured over a 0.5-cm2 area for each kVp. HU was converted to concentration using previously measured calibrations. Concentration measurements were corrected for partial volume averaging by subtracting residual slice background and extrapolating disk thickness to both nominal and measured slice sensitivity profiles (SSP, mm). Slice thickness to agreement (STTA, mm) was calculated by replacing the CT-derived concentrations with ICP-OES measurements and solving for thickness. Slice thickness correction factors improved agreement with ICP-OES for all measured data. Yb corrections resulted in lower STTA than Bi corrections in the concentration phantom (1.01 versus 1.31 STTA/SSP, where 1.0 is perfect agreement), phantoms with varying thickness (1.30 versus 1.87 STTA/SSP), and similar ratio in phantoms with varying background iodine concentration (1.34 versus 1.35 STTA/SSP). All measured concentrations correlated strongly with ICP-OES and all corrections for partial volume averaging increased agreement with ICP-OES concentration, demonstrating potential for monitoring the integrity of thin IVC resorbable filters with CT.

Rational Design of Cyanine-Based Fluorogenic Dimers to Reduce Nonspecific Interactions with Albumin and Lipid Bilayers: Application to Highly Sensitive Imaging of GPCRs in Living Cells.

Fluorogenic dimers with polarity-sensitive folding are powerful probes for live-cell bioimaging. They switch on their fluorescence only after interacting with their targets, thus leading to a high signal-to-noise ratio in wash-free bioimaging. We previously reported the first near-infrared fluorogenic dimers derived from cyanine 5.5 dyes for the optical detection of G protein-coupled receptors. Owing to their hydrophobic character, these dimers are prone to form nonspecific interactions with proteins such as albumin and with the lipid bilayer of the cell membrane resulting in a residual background fluorescence in complex biological media. Herein, we report the rational design of new fluorogenic dimers derived from cyanine 5. By modulating the chemical structure of the cyanine units, we discovered that the two asymmetric cyanine 5.25 dyes were able to form intramolecular H-aggregates and self-quenched in aqueous media. Moreover, the resulting original dimeric probes enabled a significant reduction of the nonspecific interactions with bovine serum albumin and lipid bilayers compared with the first generation of cyanine 5.5 dimers. Finally, the optimized asymmetric fluorogenic dimer was grafted to carbetocin for the specific imaging of the oxytocin receptor under no-wash conditions directly in cell culture media, notably improving the signal-to-background ratio compared with the previous generation of cyanine 5.5 dimers.

Impact of spin in compact binary foreground subtraction for estimating the residual stochastic gravitational-wave background in ground-based detectors

Impact of spin in compact binary foreground subtraction for estimating the residual stochastic gravitational-wave background in ground-based detectors

Bare mass effects on the reheating process after inflation

We consider the effects of a bare mass term for the inflaton, when the inflationary potential takes the form V(ϕ)=λϕk about its minimum with k≥4. We concentrate on k=4, but discuss general cases as well. Further, we assume λϕend2≫mϕ2, where ϕend is the inflaton field value when the inflationary expansion ends. We show that the presence of a mass term (which may be present due to radiative corrections or supersymmetry breaking) can significantly alter the reheating process, as the equation of state of the inflaton condensate changes from wϕ=13 to wϕ=0 when λϕ2 drops below mϕ2. We show that, for a mass mϕ≳3λ14TRH, the mass term will dominate at reheating. The value of λ is relatively model independent as it is normalized by the cosmic microwave background perturbation spectrum. For T models of inflation, this leads to mϕ≳TRH/250. We compute the effects on the reheating temperature for cases where reheating is due to inflaton decay (to fermions, scalars, or vectors) or to inflaton scattering (to scalars or vectors). For scattering to scalars and in the absence of a decay, there is always a residual inflaton background that acts as cold dark matter. In this case, we derive a strong upper limit to the inflaton bare mass which for T models is mϕ<350 MeV(TRH/1010 GeV)3/5. We also consider the effect of the bare mass term on the fragmentation of the inflaton condensate. Published by the American Physical Society 2024

A high resolution dilatometer using optical fiber interferometer.

We introduce a high-performance differential dilatometer based on an all-fiber Michelson interferometer at cryogenic temperature with 10-10 resolution in δL/L. It resolves the linear thermal expansion coefficient by measuring the oscillating changes of sample thickness and sample temperature with the interferometer and in situ thermometer, respectively. By measuring the linear thermal expansion coefficient α near the antiferromagnetic transition region of BaFe2As2 as a demonstration, we show that our dilatometer is able to measure thin samples with sub-pm-level length change resolution and mK-level temperature resolution. Despite the residual background thermal expansion of a few nm/K in the measurement results, our new dilatometer is still a powerful tool for the study of phase transition in condensed matter physics, especially has significant advantages in fragile materials with sub-100 μm thickness and being integrated with multiple synchronous measurements and tuning thanks to its extremely high resolution and contactless nature. The prototype design of this setup can be further improved in many aspects for specific applications.

The WIPI Model Based on Multi-Scale Local Contrast Post-Processing for Infrared Small Target Detection

According to the infrared patch image (IPI) model theory, the infrared image background has a low rank and the target is sparse. The low-rank model can be used to separate the background and identify the target. However, in a noisy environment, the recognition effect will be affected. The higher the noise, the harder it would be to detect a small target. The residual strong fault and background edges could reduce the detection rate and increase false alarms. The traditional IPI model is adaptable to the background with the lower noise. This paper combines weighted nuclear norm minimization (WNNM) optimization with sparse representation based on the local IPI model. The background details are described more prominently by improving the nuclear norm weighting factor. The target is much easier to detect under the specific bright clouds and ground buildings background with high noise. At the same time, post-processing with image local contrast analysis is performed to compare traditional spatial filtering and local infrared patch image model algorithms. Our method has a good suppression effect on complex noise backgrounds and achieves a higher signal to clutter ratio gain (SCRG). It could also improve the target detection rate and reduce false alarms.

From Shadows to Spotlight: Enhancing Bacterial DNA Detection in Blood Samples through Cutting-Edge Molecular Pre-Amplification.

One of the greatest challenges to the use of molecular methods for diagnostic purposes is the detection of target DNA that is present only in low concentrations. One major factor that negatively impacts accuracy, diagnostic sensitivity, and specificity is the sample matrix, which hinders the attainment of the required detection limit due to the presence of residual background DNA. To address this issue, various methods have been developed to enhance sensitivity through targeted pre-amplification of marker sequences. Diagnostic sensitivity to the single molecular level is critical, particularly when identifying bloodstream infections. In cases of clinically manifest sepsis, the concentration of bacteria in the blood may reach as low as one bacterial cell/CFU per mL of blood. Therefore, it is crucial to achieve the highest level of sensitivity for accurate detection. In the present study, we have established a method that fills the analytical gap between low concentrations of molecular markers and the minimum requirements for molecular testing. For this purpose, a sample preparation of whole blood samples with a directly downstream pre-amplification was developed, which amplifies specific species and resistance markers in a multiplex procedure. When applying pre-amplification techniques, the sensitivity of the pathogen detection in whole blood samples was up to 100 times higher than in non-pre-amplified samples. The method was tested with blood samples that were spiked with several Gram-positive and Gram-negative bacterial pathogens. By applying this method to artificial spiked blood samples, it was possible to demonstrate a sensitivity of 1 colony-forming unit (CFU) per millilitre of blood for S. aureus and E. faecium. A detection limit of 28 and 383 CFU per ml of blood was achieved for E. coli and K. pneumoniae, respectively. If the sensitivity is also confirmed for real clinical blood samples from septic patients, the novel technique can be used for pathogen detection without cultivation, which might help to accelerate diagnostics and, thus, to decrease sepsis mortality rates.

Cross-correlation of the thermal Sunyaev-Zel’dovich and CMB lensing signals in Planck PR4 data with robust CIB decontamination

We use the full-mission PR4 data to measure the CMB lensing convergence (κ)–thermal Sunyaev-Zel’dovich (tSZ, y) cross-correlation signal, Cℓyκ. This is only the second measurement to date of this signal, following Hill and Spergel []. We perform the measurement using foreground-cleaned tSZ maps built from the PR4 frequency maps via a tailored needlet internal linear combination (NILC) code in our companion paper [F. McCarthy and J. C. Hill, companion paper, .], in combination with the PR4 κ maps and various systematic-mitigated PR3 κ maps. A serious systematic is the residual cosmic infrared background (CIB) signal in the tSZ map, as the high CIB—κ cross-correlation can significantly bias the inferred tSZ—κ cross-correlation. We mitigate this contamination by deprojecting the CIB in our NILC algorithm, using a moment deprojection approach to avoid leakage due to incorrect modeling of the CIB frequency dependence. We validate this method on mm-wave sky simulations. We fit a theoretical halo model to our measurement, finding a best-fit amplitude of A=0.82±0.21 (for the highest signal-to-noise PR4 κ map) or A=0.56±0.24 (for a PR3 κ map built from a tSZ-deprojected CMB map), indicating that the data are consistent with our fiducial model within ≈1−2σ. Although our error bars are similar to those of the previous measurement [J. C. Hill and D. N. Spergel, ], our method is significantly more robust to CIB contamination. Our moment-deprojection approach lays the foundation for future measurements of this signal with higher signal-to-noise κ and y maps from ground-based telescopes, which will precisely probe the astrophysics of the intracluster medium of galaxy groups and clusters in the intermediate-mass (M∼1013–1014h−1M⊙), high-z (z≲1.5, c.f. z≲0.8 for the tSZ auto-power signal) regime, as well as CIB-decontaminated measurements of tSZ cross-correlations with other large-scale structure probes. Published by the American Physical Society 2024

Maximum spherical mean value filtering for whole-brain QSM.

To develop a tissue field-filtering algorithm, called maximum spherical mean value (mSMV), for reducing shadow artifacts in QSM of the brain without requiring brain-tissue erosion. Residual background field is a major source of shadow artifacts in QSM. The mSMV algorithm filters large field-magnitude values near the border, where the maximum value of the harmonic background field is located. The effectiveness of mSMV for artifact removal was evaluated by comparing existing QSM algorithms in numerical brain simulation as well as using in vivo human data acquired from 11 healthy volunteers and 93 patients. Numerical simulation showed that mSMV reduces shadow artifacts and improves QSM accuracy. Better shadow reduction, as demonstrated by lower QSM variation in the gray matter and higher QSM image quality score, was also observed in healthy subjects and in patients with hemorrhages, stroke, and multiple sclerosis. The mSMV algorithm allows QSM maps that are substantially equivalent to those obtained using SMV-filtered dipole inversion without eroding the volume of interest.

The Cryogenic Anticoincidence Detector for the NewAthena X-IFU Instrument: A Program Overview

Athena (advanced telescope for high-energy astrophysics) is an ESA large-class mission, at present under a re-definition “design-to-cost” phase, planned for a prospective launch at L1 orbit in the second half of the 2030s. It will be an observatory alternatively focusing on two complementary instruments: the X-IFU (X-ray Integral Field Unit), a TES (TransitionEdge Sensor)-based kilo-pixel array which is able to perform simultaneous high-grade energy spectroscopy (~3 eV@7 keV) and imaging over 4′ FoV (field of view), and the WFI (Wide Field Imager), which has good energy spectral resolution (~170 eV@7 keV) and imaging on wide 40′ × 40′ FoV. Athena will be a truly transformational observatory, operating in conjunction with other large observatories across the electromagnetic spectrum available in the 2030s like ALMA, ELT, JWST, SKA, CTA, etc., and in multi-messenger synergies with facilities like LIGO A+, Advanced Virgo+, LISA, IceCube and KM3NeT. The Italian team is involved in both instruments. It has the co-PIship of the cryogenic instrument for which it has to deliver the TES-based Cryogenic AntiCoincidence detector (CryoAC) necessary to guarantee the X-IFU sensitivity, degraded by a primary particle background of both solar and galactic cosmic ray (GCR) origins, and by secondary electrons produced by primaries interacting with the materials surrounding the main detector. The outcome of Geant4 studies shows the necessity for adopting both active and passive techniques to guarantee the residual particle background at 5 × 10−3 cts cm−2 s−1 keV−1 level in 2–10 keV scientific bandwidth. The CryoAC is a four-pixel detector made of Si-suspended absorbers sensed by Ir/Au TESes placed at <1 mm below the main detector. After a brief overview of the Athena mission, we will report on the particle background reduction techniques highlighting the impact of the Geant4 simulation on the X-IFU focal plane assembly design, then hold a broader discussion on the CryoAC program in terms of detection chain system requirements, test, design concept against trade-off studies and programmatic.

Charged aerodynamics: Ionospheric plasma drag on objects in low-Earth orbit

Objects in Low-Earth Orbit (LEO) experience a range of environmental conditions that influence their trajectories. Aside from gravitational effects and solar radiation pressure, drag due to the residual background atmosphere is conventionally viewed as the primary perturbing factor. The ionosphere is an additional background environment composed of charged particles that is well-known to result in spacecraft charging, and in the worst case, cause arcing or unwanted electrostatic discharges. While the ionospheric plasma density is typically an order of magnitude (or more) lower than the atmospheric neutral gas density, electrostatic charging can lead to the formation of plasma sheath and wake structures around an object that artificially increase its effective collecting area. Direct charged particle collection and indirect charged particle deflection gives rise to a drag force that can exceed that due to atmospheric neutral gas alone at some altitudes and charging potentials. Here, we present a model accounting for charged particle flow effects (i.e. charged aerodynamics) around objects in LEO, and validate this model with previous particle-in-cell simulations and experiments. Using atmospheric properties from the Mass Spectrometer and Incoherent Scatter radar (MSIS) model and ionospheric properties from the International Reference Ionosphere (IRI), we show that plasma-induced drag in LEO can be significant and may have important orbit prediction implications for space domain awareness and space traffic management. Through differential spacecraft biasing, ionospheric plasma drag can also be used as a propellantless and “solid-state” mechanism to achieve in-orbit mobility for precision maneuvers, formation flying, deorbiting, and even partial attitude control.

Quantitative susceptibility mapping identifies hippocampal and other subcortical grey matter tissue composition changes in temporal lobe epilepsy.

Temporal lobe epilepsy (TLE) is associated with widespread brain alterations. Using quantitative susceptibility mapping (QSM) alongside transverse relaxation rate ( ), we investigated regional brain susceptibility changes in 36 patients with left-sided (LTLE) or right-sided TLE (RTLE) secondary to hippocampal sclerosis, and 27 healthy controls (HC). We compared three susceptibility calculation methods to ensure image quality. Correlations of susceptibility and with age of epilepsy onset, frequency of focal-to-bilateral tonic-clonic seizures (FBTCS), and neuropsychological test scores were examined. Weak-harmonic QSM (WH-QSM) successfully reduced noise and removed residual background field artefacts. Significant susceptibility increases were identified in the left putamen in the RTLE group compared to the LTLE group, the right putamenand right thalamus in the RTLE group compared to HC, and a significant susceptibility decrease in the left hippocampus in LTLE versus HC. LTLE patients who underwent epilepsy surgery showed significantly lower left-versus-right hippocampal susceptibility. Significant changes were found between TLE and HC groups in the amygdala, putamen, thalamus, and in the hippocampus. Specifically, decreased R2 * was found in the left and right hippocampus in LTLE and RTLE, respectively, compared to HC. Susceptibility and were significantly correlated with cognitive test scores in the hippocampus, globus pallidus, and thalamus. FBTCS frequency correlated positively with ipsilateral thalamic and contralateral putamen susceptibility and with in bilateral globi pallidi. Age of onset was correlated with susceptibility in the hippocampus and putamen, and with in the caudate. Susceptibility and changes observed in TLE groups suggest selective loss of low-myelinated neurons alongside iron redistribution in the hippocampi, predominantly ipsilaterally, indicating QSM's sensitivity to local pathology. Increased susceptibility and in the thalamus and putamen suggest increased iron content and reflect disease severity.

High resistive buffer layers by Fermi level engineering

An efficient carrier compensation mechanism in semiconductor layers by Fermi-level engineering is demonstrated using the modulation-doping of a deep acceptor and a shallow donor. The punch-through of the depletion region across the whole stack of modulation-doped layers shifts the Fermi level closer toward the midgap position, resulting in the compensation of residual background free carriers. The method represents an alternative to achieve semi-insulating properties in semiconductor materials where a suitable deep acceptor or donor state at the midgap position is not available. We demonstrate the applicability of the concept with a commercially important GaN case study using carbon (deep acceptor) and Si (shallow donor) doping. A strong enhancement of breakdown field strength and reduced charge pileup effects are observed due to the efficient pinning of the Fermi level.

Deep learning phase error correction for cerebrovascular 4D flow MRI

Background phase errors in 4D Flow MRI may negatively impact blood flow quantification. In this study, we assessed their impact on cerebrovascular flow volume measurements, evaluated the benefit of manual image-based correction, and assessed the potential of a convolutional neural network (CNN), a form of deep learning, to directly infer the correction vector field. With IRB waiver of informed consent, we retrospectively identified 96 MRI exams from 48 patients who underwent cerebrovascular 4D Flow MRI from October 2015 to 2020. Flow measurements of the anterior, posterior, and venous circulation were performed to assess inflow-outflow error and the benefit of manual image-based phase error correction. A CNN was then trained to directly infer the phase-error correction field, without segmentation, from 4D Flow volumes to automate correction, reserving from 23 exams for testing. Statistical analyses included Spearman correlation, Bland–Altman, Wilcoxon-signed rank (WSR) and F-tests. Prior to correction, there was strong correlation between inflow and outflow (ρ = 0.833–0.947) measurements with the largest discrepancy in the venous circulation. Manual phase error correction improved inflow-outflow correlation (ρ = 0.945–0.981) and decreased variance (p < 0.001, F-test). Fully automated CNN correction was non-inferior to manual correction with no significant differences in correlation (ρ = 0.971 vs ρ = 0.982) or bias (p = 0.82, Wilcoxon-Signed Rank test) of inflow and outflow measurements. Residual background phase error can impair inflow-outflow consistency of cerebrovascular flow volume measurements. A CNN can be used to directly infer the phase-error vector field to fully automate phase error correction.

Partial degeneration of finite gap solutions to the Korteweg–de Vries equation: soliton gas and scattering on elliptic backgrounds

We obtain Fredholm type formulas for partial degenerations of theta functions on (irreducible) nodal curves of arbitrary genus, with emphasis on nodal curves of genus one. An application is the study of ‘many-soliton’ solutions on an elliptic (cnoidal) background standing wave for the Korteweg–de Vries (KdV) equation starting from a formula that is reminiscent of the classical Kay–Moses formula for N-solitons. In particular, we represent such a solution as a sum of the following two terms: a ‘shifted’ elliptic (cnoidal) background wave and a Kay–Moses type determinant containing Jacobi theta functions for the solitonic content, which can be viewed as a collection of solitary disturbances on the cnoidal background. The expressions for the travelling (group) speed of these solitary disturbances, as well as for the interaction kernel describing the scattering of pairs of such solitary disturbances, are obtained explicitly in terms of Jacobi theta functions. We also show that genus N + 1 finite gap solutions with random initial phases converge in probability to the deterministic cnoidal wave solution as N bands degenerate to a nodal curve of genus one. Finally, we derive the nonlinear dispersion relations and the equation of states for the KdV soliton gas on the residual elliptic background.

Two-frame Phase-shifting Interferometry by Minimizing the Residual-background

Demodulation of two random phase shift fringe patterns is an ill-posed problem. Existing methods often need to remove the fringe background by pre filtering in the frequency, which takes more time, and have a great influence on the phase reconstruction because of the frequency aliasing, these limits the application of two frame phase-shift interferometry in actual production. In this case, this paper based on the idea of Statistical Average, proposes a Statistical Average technology for phase extraction of two frame randomly phase-shifted interferograms from rough to precision without pre filtering. The proposed methods based on minimizing the residual background, firstly estimates the average background by calculating the average for all pixels, and then adding and subtracting the two frames with the background removed. The phase shift and phase are solved by using the properties of trigonometric functions. Then the amplitude is solved using the obtained phase and phase shift. Finally, the background is solved and the original light intensity is updated. Compared with existing methods, our method has the advantages such as rapid convergence and quick calculation by offering the right initial value. The accuracy of my proposed method is approximately double that of existing methods. Simulation and experimental results show that our method is a practical method of two frame phase shift interferences, both simple and reliable.

High-resolution Cs-Rb two-photon spectrometer for directly stabilizing a Ti:sapphire comb laser.

In this paper, we present a simple scheme for efficiently removing the residual Doppler background of a comb laser based two-photon spectrometer to be better than 10-3 background-to-signal ratio. We applied this scheme to stabilize the frequencies of a mode-locked Ti:sapphire laser directly referring to the cesium 6S-8S transition and rubidium 5S-5D transition. We suggest a standard operation procedure (SOP) for the fully direct comb laser stabilization and evaluate the frequency of two spectral lines at a certain temperature, by which we demonstrate an all-atomic-transition-based Ti:sapphire comb laser merely via a 6-cm glass cell.