- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Enhancement of optical penetration depth of LED-based NIRS systems by comparing different beam profiles
摘要： Near-Infrared Spectroscopy (NIRS) is a non-invasive brain imaging technique involving the quantification of oxy and deoxy-hemoglobin concentrations resolved from the measurement of Near-Infrared (NIR) light attenuation within the tissue. Previous studies have shown that NIR light is more influenced by the optical properties of the superficial layers than those of the deeper target layers such as cortex. NIR light produced by the Laser source penetrates deeper regions of the tissue rather than the LED source although Laser needs more expensive instrumentation. In this study, we investigate the effect of Uniform and Gaussian beam profiles on the enhancement of LED light penetration depth. The latter beam profiles were generated and compared using Flat and Aspherical lenses applied to the LED sources. In order to increase the signal to noise ratio, the lenses were also applied to the light detector. For performance analysis, two experiments were carried out by scanning the intra space of a liquid phantom by static and dynamic (pulsating) absorbers. Monte Carlo simulations were also carried out to be compared with the experiment. The results showed that Gaussian beam profile and in particular, Bi-Convex lenses applied to both source and detector leads to a greater light penetration depth in the liquid phantom close to that of a Laser source.
关键词： near infrared spectroscopy,optical sensors,biomedical optic,monte carlo simulation,instrumentation
更新于2025-09-23 15:19:57
-
Surface-enhanced Raman scattering from buffer layer under graphene on SiC in a wide energy range from visible to near-infrared
摘要： Raman signals from the buffer layer between graphene and a SiC substrate are enhanced through the formation of nano-structured Au deposited directly on graphene grown on SiC. This simple method makes it possible to deconvolute multiple graphene and buffer layer peaks in a wide energy range from 1.58 to 2.33 eV and find new buffer layer peaks that are not resolved in conventional Raman scattering spectroscopy. Furthermore, we clearly show a small linear excitation energy dependence for one of the buffer layer peak positions and an absence of energy dependence for the peaks at most of the other positions.
关键词： buffer layer,Surface-enhanced Raman scattering,graphene,SiC,near-infrared
更新于2025-09-23 15:19:57
-
Advances and perspectives in neara??infrared fluorescent organic probes for surgical oncology
摘要： Surgical resection of solid tumors is currently the most efficient and preferred therapeutic strategy for treating cancer. Despite significant medical, technical, and scientific advances, the complete treatment of this lethal disease is still a challenging task. New imaging techniques and contrast agents are urgently needed to improve cytoreductive surgery and patient outcomes. Tumor-targeted probes are valuable for guiding a surgical resection of tumor from subjective judgments to visual inspection. Near-infrared (NIR) fluorescent imaging is a promising technology in preclinical and clinical tumor diagnosis and therapy. The rapid development in NIR fluorophores with improved optical properties, targeting strategies, and imaging devices has brought about prospective study of novel NIR nanomaterials for intraoperative tumor detection. In this review, we summarize the recent development in NIR-emitting organic fluorophores and cancer-targeting strategies that specifically target and accumulate in tumors for the molecular imaging of cancerous cells. We believe this technique utilizing new fluorescent probes with an intraoperative optical imaging capacity could provide a more sensitive and accurate method for cancer resection guidance, thereby resulting in better surgical outcomes.
关键词： cancer detection,intraoperative optical imaging,near-infrared fluorescent probes,surgical resection
更新于2025-09-23 15:19:57
-
Analytical Methods of Equivalent Circuit Model and Transmission Matrix for a Plasmonic Switch with Sensing Capability in Near-Infrared Region
摘要： In this paper, the simultaneous switching and sensing capabilities of a compact plasmonic structure based on a conventional rectangular hole in a silver film are proposed and investigated. The proposed structure has ultrahigh sensitivity up to 3000 nm/RIU and high figure of merit of 170 RIU?1. Also, the simulation results show the potential of the presented refractive index sensor to detect malaria infection, cancer cells, bacillus bacteria, and solution of glucose in water. Simultaneously, by changing the incident lightwave polarization, the structure behaves like a plasmonic switch, which has high extinction ratios of 15.81, 31.20, and 25.03 dB at three telecommunication wavelengths of 850, 1310, and 1550 nm, respectively. The ultrafast response time of 20 fs is achieved for the wideband application of the switching capability at the wavelength range of 1056 to 1765 nm. Moreover, the equivalent circuit model and transmission (ABCD) matrix methods are derived to validate the simulated results. Simple design, good agreement between the numerical and analytical results, biomedical applications, ultrahigh sensitivity, and ultrafast performance of the proposed structure help this idea to open up paths for design and implementation of other multi-application plasmonic devices in near-infrared region. To the best of our knowledge, the mentioned analytical methods have not been studied former at near-infrared wavelengths. Therefore, the achievements could pave the way for verifying the simulation results of plasmonic nanostructures in future investigations.
关键词： Near-infrared,Switch,Circuit model,Transmission matrix,Sensor,Biomedical,Polarization-multiplexing,Plasmonic
更新于2025-09-23 15:19:57
-
Neara??Infrared Lighta??Induced Sequential Shape Recovery and Separation of Assembled Temperature Memory Polymer Microparticles
摘要： Light-induced, shape-changing polymeric microparticles have many applications. Here, the near-infrared (NIR)-light-triggered sequential recovery and separation of assembled large and small polymer microparticles using cross-linked blends of poly(ethylene-vinyl acetate) and trans-polyisoprene as temperature memory polymers as well as two NaYF4 based up-conversion nanoparticles (UCPs) to provide luminescent and photothermal effects are reported. Under irradiation of NIR light with a low light power density, small particles assembled onto the compressed large one recover first due to the low switching temperature (Tsw) arising from the temperature–memory effect. The small particles can separate from the underlying large particle in flowing aqueous media. The recovery of the large particle occurs at a high power density. Two UCPs of NaYF4: 20Yb, 0.2Tm, 5Gd and NaYF4: 18Yb, 2Er, 5Gd facilitate the detection of small and large microparticles via providing blue and green light emissions, respectively. This work can expand the applications of light-induced shape-changing polymer microparticles in the biomedical field, controlled catalysis, microfluidic devices, and so on.
关键词： up-conversion nanoparticles,temperature-memory effect,polymer microparticles,near-infrared light
更新于2025-09-23 15:19:57
-
Macrostickies measurement by an automated method using laser triangulation and near infrared spectroscopy
摘要： In recycled paper processes, stickies are at the origin of many production disturbances, such as machine breaks, defects in paper and converting problems. Typically, a macrostickies measurement involves separating them from the pulp by screening, then characterising by one of the available inspection and classification methods. The most recognized method in Europe is INGEDE#4. It gives useful information about stickies particles count and size. However the measurement is time-consuming, because of the manual preparation involving numerous steps. In this work, we present an automated macro-contaminant measurement method which allows to (i) determine the 3 dimensional morphology of screened particles (without any deformation) and (ii) classify the particles as stickies among contaminants. This is achieved by a combination of laser triangulation and local near-infrared (NIR) spectroscopy. Starting from the screened contaminants deposited on a filter paper, the stickies measurement is fully automated. The stickies count results from the proposed method are closely correlated with those from the INGEDE#4 method.
关键词： Contaminants,Stickies,Sensor,Recycled pulp,Near infrared spectroscopy,Laser triangulation
更新于2025-09-23 15:19:57
-
Open-Source Python Module for Automated Preprocessing of Near Infrared Spectroscopic Data
摘要： Near infrared spectroscopy (NIRS) is an analytical technique for determining the chemical composition or structure of a given sample. For several decades, NIRS has been a frequently used analysis tool in agriculture, pharmacology, medicine, and petrochemistry. The popularity of NIRS is constantly growing as new application areas are discovered. Contrary to mid infrared spectral region, the absorption bands in near infrared spectral regions are often non-specific, broad, and overlapping. Analysis of NIR spectra requires multivariate methods which are highly subjective to noise arising from instrumentation, scattering effects, and measurement setup. NIRS measurements are also frequently performed outside of a laboratory which further contributes to the presence of noise. Therefore, preprocessing is a critical step in NIRS as it can vastly improve the performance of multivariate models. While extensive research regarding various preprocessing methods exists, selection of the best preprocessing method is often determined through trial-and-error. A more powerful approach for optimizing preprocessing in NIRS models would be to automatically compare a large number of preprocessing techniques (e.g., through grid-search or hyperparameter tuning). To enable this, we present, nippy, an open-source Python module for semi-automatic comparison of NIRS preprocessing methods (available at https://github.com/uef-bbc/nippy). We provide here a brief overview of the capabilities of nippy and demonstrate the typical usage through two examples with public datasets.
关键词： Near infrared spectroscopy,Chemometrics,Preprocessing
更新于2025-09-23 15:19:57
-
Transcranial Photobiomodulation (tPBM) With 1,064a??nm Laser to Improve Cerebral Metabolism of the Human Brain In Vivo
摘要： Background and Objectives: In our previous proof‐of‐principle study, transcranial photobiomodulation (tPBM) with 1,064‐nm laser was reported to significantly increase concentration changes of oxygenated hemoglobin (Δ[HbO]) and oxidized‐state cytochrome c oxidase (Δ[oxi‐CCO]) in the human brain. This paper further investigated (i) its validity in two different subsets of young human subjects at two study sites over a period of 3 years and (ii) age‐related effects of tPBM by comparing sham‐controlled increases of Δ[HbO] and Δ[oxi‐CCO] between young and older adults. Study Design/Materials and Methods: We measured sham‐controlled Δ[HbO] and Δ[oxi‐CCO] using broadband near‐infrared spectroscopy (bb‐NIRS) in 15 young (26.7 ± 2.7 years of age) and 5 older (68.2 ± 4.8 years of age) healthy normal subjects before, during, and after right‐forehead tPBM/sham stimulation with 1,064‐nm laser. Student t tests were used to test statistical differences in tPBM‐induced Δ[HbO] and Δ[oxi‐CCO] (i) between the 15 young subjects and those of 11 reported previously and (ii) between the two age groups measured in this study. Results: Statistical analysis showed that no significant difference existed in Δ[HbO] and Δ[oxi‐CCO] during and post tPBM between the two subsets of young subjects at two study sites over a period of 3 years. Furthermore, the two age groups showed statistically identical net increases in sham‐controlled Δ[HbO] and Δ[oxi‐CCO]. Conclusions: This study provided strong evidence to validate/confirm our previous findings that tPBM with 1,064‐nm laser enables to increase cerebral Δ[HbO] and Δ[oxi‐CCO] in the human brain, as measured by bb‐NIRS. Overall, it demonstrated the robust reproducibility of tPBM being able to improve cerebral hemodynamics and metabolism of the human brain in vivo in both young and older adults.
关键词： transcranial photobiomodulation,cytochrome c oxidase,reproducibility,broadband near‐infrared spectroscopy,tPBM
更新于2025-09-23 15:19:57
-
Mineralogy of Changa??e-4 landing site: preliminary results of visible and near-infrared imaging spectrometer
摘要： The exploration of ma?c anomaly in South Pole-Aitken (SPA, the largest con?rmed) basin on the Moon provides important insights into lunar interior. The landing of Chang’e-4 (CE-4) and deployment of Yutu-2 rover on the discontinuous ejecta from Finsen crater enabled in-situ measurements of the unusual mineralogy in the central portion of SPA basin with visible and near-infrared imaging spectrometer (VNIS). Here we present detailed processing procedures based on the level 2B data of CE-4 VNIS and preliminary mineralogical results at the exploration area of Yutu-2 rover. A systematic processing pipeline is developed to derive credible re?ectance spectra, based on which several spectral and mineral indices are calculated to constrain the ma?c mineralogy. The ma?c components in the soils and boulder around CE-4 landing site are concluded as clinopyroxene-bearing with intermediate composition and probably dominated by pigeonite although the possibility of mixing orthopyroxen (OPX) and calcic clinopyroxene (CPX) also exists. These mineralogical results are more consistent with a petrogenesis that the CE-4 regolith and rock fragment are derived from rapid-cooling magmatic systems and we interpret that the materials at the CE-4 landing site ejected from Finsen crater are probably recrystallized from impact melt settings.
关键词： Chang’e-4,the Moon,visible and near-infrared spectroscopy,mineralogy,impact melt
更新于2025-09-23 15:19:57
-
Near-Infrared Electron Acceptors with Unfused Architecture for Efficient Organic Solar Cells
摘要： Nonfullerene acceptor (NFA) with near-infrared (NIR) region absorption is crucial for obtaining high current densities in organic solar cells (OSCs). Herein, two narrow bandgap NFAs with unfused backbones possessing broad (600-900 nm) and strong absorption are developed by the conjugation of a benzothiadiazole (BT) core to halogenated end-groups through cyclopentadithiophene (CPDT) bridge. Compared with the fluorinated counterpart BCDT-4F, the chlorinated NFA BCDT-4Cl appears stronger J-aggregation and closer molecular packing, leading to the optimized blend morphology when paired with polymer donor, PBDB-T. Thus, an obvious improvement of external quantum efficiency response was obtained for BCDT-4Cl based OSCs, presenting a higher efficiency of 12.10% than that (9.65%) based on BCDT-4F. This work provides a design strategy for NIR acceptors in the combination of electron deficient core and halogenated terminal in unfused backbone, which results in not only fine-tuning of optoelectronic properties, but also the simplified synthetic complexities of molecule.
关键词： electron-deficient core,organic solar cell,halogenated end-group,unfused architecture,near-infrared electron acceptor
更新于2025-09-23 15:19:57