Design and fabrication of far ultraviolet filters based on π-multilayer technology in high-k materials

Wang, Xiaodong; Wang, Haifeng; He, Fei; Zheng, Xin; He, Liwen; Chen, Bin; Liu, Shijie; Cui, Zhong-Xu; Yang, Xiaohu; Liu, Yunpeng

doi:10.1038/srep08503

Cited by 30 publications

(41 citation statements)

References 29 publications

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“…In contrast to the fingerprint region, not many background subtraction algorithms have been developed for the high-wavenumber region of the Raman spectrum. [7,9,[21][22][23][24][25][26][27][28]46] For high-wavenumber region spectra, PBF is the only solution mentioned for background correction, using either a first-order [3,10,[12][13][14][15] or a fifth-order polynomials. [11] However, this method produced unsatisfactory results for our ex vivo high-wavenumber spectra of human oral tissues.…”

Section: Discussionmentioning

confidence: 99%

“…Raman spectroscopy has been broadly explored for medical applications in oncology aiming at early diagnosis, biopsy guidance, and surgery guidance. [1][2][3] The technique can provide qualitative and quantitative molecular information about tissues and enables classification of tissues with high sensitivity and specificity. Raman spectroscopy is directly applicable for in vivo and ex vivo analysis of tissue, without the need for labels and/or reagents.…”

Section: Introductionmentioning

confidence: 99%

“…[5] To overcome this, both hardware-and softwarebased strategies have been developed to reduce the interference from luminescence. [3, An example of a hardware-based strategy is the use of specific excitation wavelengths far from the visible range. For example, the intensity of a fluorophore is dependent on the excitation wavelength.…”

Section: Introductionmentioning

confidence: 99%

“…Polynomial subtractions of first and fifth orders are the few and most common solutions mentioned for background correction in the high-wavenumber region. [3,[10][11][12][13][14][15] First-order polynomial subtraction has been used on high-wavenumber Raman spectra acquired from oral cavity (gingiva, buccal, dorsal tongue, and palate), adenomatous polyps, esophageal squamous cell carcinoma, nasopharyngeal tissues, and breast tissue. [3,10,[12][13][14][15] The spectra in these studies were acquired with fiber-optic Raman probes and a confocal Raman microscope.…”

Section: Introductionmentioning

confidence: 99%

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Characterization and subtraction of luminescence background signals in high‐wavenumber Raman spectra of human tissue

Barroso

Schut

Santos

et al. 2018

J Raman Spectroscopy

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Raman spectroscopy in the high-wavenumber spectral region (HWR) is particularly suited for fiber-optic in vivo medical applications. The most-used fiber-optic materials have negligible Raman signal in the HWR. This enables the use of simple and cheap single-fiber-optic probes that can be fitted in endoscopes and needles. The HWR generally shows less tissue luminescence than the fingerprint region. However, the luminescence can still be stronger than the Raman signal. Hardware-and software-based strategies have been developed to correct for these luminescence signals. Typically, hardwarebased strategies are more complex and expensive than software-based solutions. Effective software strategies have almost exclusively been developed for the fingerprint region. First-order polynomial baseline fitting (PBF) is the most common background/luminescence estimation employed for the HWR. The goal of this study was to characterize the luminescence background signals of HW spectra of human oral tissue and compare the performance of two algorithms for correction of these background signals: PBF and multiple regression fitting (MRF). In the MRF method, we introduce here, prior knowledge of the range of Raman signals that can be obtained from the tissues of interest is explicitly used. MRF is more robust than PBF because it does not require an a priori choice of the polynomial order for fitting the background signal. This is important because, as we show, no single polynomial order can optimally characterize all backgrounds that are encountered in HW tissue spectra. We conclude that MRF should be the preferred method for background subtraction in the HWR.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Characterization and subtraction of luminescence background signals in high‐wavenumber Raman spectra of human tissue

Barroso

Schut

Santos

et al. 2018

J Raman Spectroscopy

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“…Metal–organic frameworks (MOFs) are a new generation of highly porous macromolecular structures composed of metal ions or clusters linked by multidentate organic bridging ligands, which, owing to their attractive properties, have notable potential for applications in different contexts, including gas capture, storage and separation, catalysis, water treatment and drug delivery . MOFs have almost infinite tunability due to the effectively unlimited range of metal ions and ligands available to form their structures .…”

Section: Introductionmentioning

confidence: 99%

Multivariate Modulation of the Zr MOF UiO‐66 for Defect‐Controlled Combination Anticancer Drug Delivery

2020

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Metal–organic frameworks (MOFs) are emerging as leading candidates for nanoscale drug delivery, as a consequence of their high drug capacities, ease of functionality, and the ability to carefully engineer key physical properties. Despite many anticancer treatment regimens consisting of a cocktail of different drugs, examples of delivery of multiple drugs from one MOF are rare, potentially hampered by difficulties in postsynthetic loading of more than one cargo molecule. Herein, we report a new strategy, multivariate modulation, which allows incorporation of up to three drugs in the Zr MOF UiO‐66 by defect‐loading. The drugs are added to one‐pot solvothermal synthesis and are distributed throughout the MOF at defect sites by coordination to the metal clusters. This tight binding comes with retention of crystallinity and porosity, allowing a fourth drug to be postsynthetically loaded into the MOFs to yield nanoparticles loaded with cocktails of drugs that show enhancements in selective anticancer cytotoxicity against MCF‐7 breast cancer cells in vitro. We believe that multivariate modulation is a significant advance in the application of MOFs in biomedicine, and anticipate the protocol will also be adopted in other areas of MOF chemistry, to easily produce defective MOFs with arrays of highly functionalised pores for potential application in gas separations and catalysis.

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One‐Structure‐Based Barrier Film for Simultaneous Exclusion of Water and Ultraviolet Light

Lee

Gim

Park

et al. 2016

Advanced Optical Materials

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CommuniCation(1 of 5) 1600888 UV barrier films on the flexible substrate.Furthermore, multilayer barrier films exhibit high Fresnel reflection loss at visible wavelengths (≈400 ≤ λ ≤ ≈700 nm) as a result of differences in the refractive indices of barrier layers. [27] By using an optical design to create a film that is impermeable to both water and UV, these problems will be overcome.In this letter, we propose a new type of multifunctional barrier film that prevents penetration by both water and UV light (Figure 1). To enable a low-cost and simple process, we developed a fabrication approach that uses UV-distributed Bragg reflector (UV-DBR) structures to combines thin-film passivation and a UV reflector. Layers of passivation materials (Si x N y , SiO 2 ) were alternated ("SN/SO pairs") in the UV-DBR structure, so water transmission was reduced. Simulation was conducted to optimize the thickness of SiO 2 and Si x N y to block UV light (λ < 400 nm) while maintaining visible transparency. According to finite difference time domain (FDTD) simulations, UV light can be remarkably reflected by the UV-DBR because of the welldesigned Bragg reflector structure. The UV-DBR structure with 10 SN/SO pairs reduced UV transmittance UT (wavelengths 200 ≤ λ ≤ 400 nm) to ≈1.6% while maintaining visible transmittance VT ≈ 78.9%.To design the UV-DBR structure, optical simulation was performed using Macleod (Thin Film Center, Inc.), which is based on the characteristics matrix method for optical analysis involving a multilayer structure. The optical constants of Si x N y and SiO 2 were measured using spectroscopic ellipsometry. Si x N y has an energy bandgap >4 eV, so it can protect against high-energy UV radiation (λ < 300 nm). [28] Therefore, optical simulation was conducted to optimize the thicknesses of SiO 2 and Si x N y to block UV (300 < λ < 400 nm). To determine the optimum thickness, five kinds of UV-DBR structure were considered (Figure 2a). In the design of the UV-DBR samples, a DBR structure with 10 SN/SO pairs (10-pair UV-DBR) was used, and center wavelengths were 310 ≤ λ c ≤ 390 nm. At 350 ≤ λ c ≤ 390 nm, UT was minimized to ≈3.0%. However, at λ c = 310 and 330 nm, 5.3 ≤ UT ≤ 7.9%. The average visible transmittance VT avg gradually decreased from 83.7% to 75.4% as λ c increased (Figure 2b). λ c = 350 nm was chosen as the best compromise between blocking of UV and maintenance of VT (81.8%). To obtain these values, the thicknesses of Si x N y and SiO 2 layers were calculated as t = λ/4n, where n is the refractive index of Si x N y (n = 2.3) and SiO 2 (n = 1.6) layers. For Si x N y , t = 41 nm; for SiO 2 , t = 54 nm. To study the angular dependency of UV-DBR, its UT and VT (Figure 2c) were calculated for incident angles 0°-80° to the normal. Three structures Si x N y (41 nm, Figure S2, Supporting Information), SiO 2 (54 nm, Figure S2, Supporting Information), and 10-pair UV-DBR (Figure 2c) on glass were simulated. Both Si x N y and SiO 2 samples had high angular UT (Si x N y = 49.6%, SiO 2 = 84.7% at 0°),

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Design and fabrication of far ultraviolet filters based on π-multilayer technology in high-k materials

Cited by 30 publications

References 29 publications

Characterization and subtraction of luminescence background signals in high‐wavenumber Raman spectra of human tissue

Characterization and subtraction of luminescence background signals in high‐wavenumber Raman spectra of human tissue

Multivariate Modulation of the Zr MOF UiO‐66 for Defect‐Controlled Combination Anticancer Drug Delivery

One‐Structure‐Based Barrier Film for Simultaneous Exclusion of Water and Ultraviolet Light

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