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1.
Braz. j. biol ; 84: e252364, 2024. graf
Artículo en Inglés | MEDLINE, LILACS, VETINDEX | ID: biblio-1355885

RESUMEN

Abstract Understanding morphological and physiological changes under different light conditions in native fruit species in juveniles' stage is important, as it indicate the appropriate environment to achieve vigorous saplings. We aimed to verify growth and morphophysiological changes under shade gradient in feijoa (Acca sellowiana (O. Berg) Burret) to achieve good quality saplings adequate to improve cultivation in orchards. The saplings were grown for twenty-one-month under four shading treatments (0%, 30%, 50%, and 80%). Growth, photosynthetic pigments, gas exchanges, chlorophyll fluorescence, and leaf anatomy parameters were evaluated. Saplings under full sun and 30% shade had higher height and diameter growth and dry mass accumulation due to higher photosynthesis rate. As main acclimatization mechanisms in feijoa saplings under 80% shade were developed larger leaf area, reduced leaf blade thickness, and enhanced quantum yield of photosystem II. Even so, the net CO2 assimilation and the electron transport rate was lower and, consequently, there was a restriction on the growth and dry mass in saplings under deep shade. Therefore, to obtain higher quality feijoa saplings, we recommend that it be carried out in full sun or up to 30% shade, to maximize the sapling vigor in nurseries and, later, this light environment can also be used in orchards for favor growth and fruit production.


Resumo A verificação de mudanças morfológicas e fisiológicas sob diferentes condições luminosas em espécies frutíferas nativas em estágio juvenil é importante, uma vez que indicam o ambiente adequado para a formação de mudas com alto vigor. Objetivou-se verificar o crescimento e as alterações morfofisiológicas sob gradiente de sombreamento em mudas de feijoa (Acca sellowiana (O. Berg) Burret) para obter mudas de boa qualidade, adequadas para fomentar os plantios da espécie em pomares. As mudas foram cultivadas por vinte e um meses sob quatro tratamentos de sombreamento (0%, 30%, 50% e 80%). Foram avaliados parâmetros de crescimento, pigmentos fotossintéticos, trocas gasosas, fluorescência da clorofila e anatomia foliar. Mudas a pleno sol e 30% de sombra apresentaram maior crescimento em altura, diâmetro e acúmulo de massa seca, devido à maior taxa de fotossíntese. Como principais mecanismos de aclimatação sob 80% de sombra, as mudas desenvolveram maior área foliar, redução da espessura do limbo foliar e aumento do rendimento quântico do fotossistema II. Mesmo assim, a assimilação líquida de CO2 e a taxa de transporte de elétrons foram menores e, consequentemente, houve restrição ao crescimento e acúmulo de massa seca das mudas no maior nível de sombreamento. Portanto, para a obtenção de mudas de feijoa de maior qualidade, recomendamos que seja realizada a pleno sol ou até 30% de sombra, para maximizar o vigor das mudas em viveiros e, posteriormente, este ambiente de luz também pode ser utilizado em pomares para favorecer o crescimento e a produção de frutos.


Asunto(s)
Myrtaceae , Feijoa , Fotosíntesis , Hojas de la Planta , Aclimatación , Luz
2.
J Integr Plant Biol ; 64(2): 564-591, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34962073

RESUMEN

Photosynthesis started to evolve some 3.5 billion years ago CO2 is the substrate for photosynthesis and in the past 200-250 years, atmospheric levels have approximately doubled due to human industrial activities. However, this time span is not sufficient for adaptation mechanisms of photosynthesis to be evolutionarily manifested. Steep increases in human population, shortage of arable land and food, and climate change call for actions, now. Thanks to substantial research efforts and advances in the last century, basic knowledge of photosynthetic and primary metabolic processes can now be translated into strategies to optimize photosynthesis to its full potential in order to improve crop yields and food supply for the future. Many different approaches have been proposed in recent years, some of which have already proven successful in different crop species. Here, we summarize recent advances on modifications of the complex network of photosynthetic light reactions. These are the starting point of all biomass production and supply the energy equivalents necessary for downstream processes as well as the oxygen we breathe.


Asunto(s)
Luz , Fotosíntesis
3.
Comput Intell Neurosci ; 2022: 9832244, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35498172

RESUMEN

In today's highly urbanized world, indoor space is becoming more extensive and more complex, and under the increasingly urgent needs, indoor positioning has attracted people's attention. With the rapid development of LED lighting technology, indoor positioning technology based on visible light communication has many advantages over traditional indoor positioning technology. Aiming at the influence of environmental factors such as noise and reflected light on the positioning accuracy, the compression perception theory is applied to the localization of visible light. The position of the receiving end in the positioning space is defined as a sparse variable in the discrete space. The power measurement matrix is expressed as the product of the observation matrix, and the sparse matrix and sparse vector in the compression perception theory are expressed. The traditional APIT algorithm is easy to misjudge unknown nodes in the triangle, resulting in low positioning accuracy of the algorithm. In this study, an indoor visible positioning algorithm based on hybrid APIT is proposed, which uses the area relationship of the triangle to determine the initial position of the unknown node, and then uses the tangent circle to further narrow the area where the unknown node may be located, and uses the hybrid centroid localization algorithm to obtain the estimated position of the unknown node.


Asunto(s)
Compresión de Datos , Algoritmos , Humanos , Luz , Iluminación , Tecnología
4.
Yakugaku Zasshi ; 142(5): 503-511, 2022.
Artículo en Japonés | MEDLINE | ID: mdl-35491156

RESUMEN

Technologies for the optical control of biomolecular functions have recently attracted considerable attention because they can be combined with advanced laser and microscopic techniques for diverse applications at the cellular and intravital levels. In this account, I review the summary of optical control technologies for biomolecular functions based on organic chemistry or protein science, and then introduce our recent studies on the development of small molecule-based photoregulation techniques. The first is the development of a photoactivatable protein labeling method based on a caged ligand. This method was applied to the photocontrol of intracellular protein dimerization and localization. The second is the development of a reversibly photoswitchable enzyme inhibitor, which was designed from the conformation of the inhibitor in the crystal structure of the enzyme-inhibitor complex. Based on our research strategies and results, I have also outlined the respective advantages and disadvantages of these two technologies: caged compounds and photoswitchable compounds.


Asunto(s)
Fenómenos Fisiológicos Celulares , Proteínas , Ligandos , Luz
5.
Methods Mol Biol ; 2451: 245-258, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35505022

RESUMEN

Metal-based compounds have been used to treat cancer for decades, with cisplatin being the most common and widely used. Photodynamic therapy (PDT) is another clinical modality used to fight cancer, which uses a photosensitizer (PS) that localizes in cancer tissues. This PS is activated by the illumination of the tumor with visible light. Photoactivated chemotherapy (PACT) is a new concept that brings these two ideas together. Like PDT , PACT aims at sparing healthy tissues while maintaining toxicity against cancerous cells. Unlike PDT , which often stops working when the concentration of dioxygen in illuminated tissues is too low, light activation of PACT compounds remains efficient in hypoxic cancer cells. This chapter addresses the methodology to experimentally measure the phototoxicity of PACT compounds in cancer cell lines, under both normoxic and hypoxic conditions.


Asunto(s)
Neoplasias , Fotoquimioterapia , Cisplatino , Humanos , Luz , Neoplasias/tratamiento farmacológico , Fotoquimioterapia/métodos , Fármacos Fotosensibilizantes/farmacología , Fármacos Fotosensibilizantes/uso terapéutico
6.
Methods Mol Biol ; 2451: 521-531, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35505029

RESUMEN

Photodynamic therapy (PDT) has a great therapeutic potential because it induces local cellular cytotoxicity upon application of a laser light that excites a photosensitizer, leading to toxic reactive oxygen species. Nevertheless, PDT still is underutilized in the clinic, mostly because of damage induced to normal surrounding tissues. Efforts have been made to improve the specificity. Nanobody-targeted PDT is one of such approaches, in which the variable domain of heavy-chain antibodies, i.e., nanobodies, are used to target photosensitizers selectively to cancer cells. In vitro studies are certainly very valuable to evaluate the therapeutic potential of PDT approaches, but many aspects such as bio-distribution of the photosensitizers, penetration through tissues, and clearance are not taken into account. In vivo studies are therefore essential to assess the influence of such factors, in order to gain more insights into the therapeutic potential of a treatment under development. This chapter describes the development of an orthotopic model of head and neck cancer, to which nanobody-targeted PDT is applied, and the therapeutic potential is assessed by immunohistochemistry one day after PDT.


Asunto(s)
Neoplasias de Cabeza y Cuello , Fotoquimioterapia , Anticuerpos de Dominio Único , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Humanos , Luz , Fármacos Fotosensibilizantes/química , Fármacos Fotosensibilizantes/farmacología , Fármacos Fotosensibilizantes/uso terapéutico , Anticuerpos de Dominio Único/farmacología , Anticuerpos de Dominio Único/uso terapéutico
7.
Methods Mol Biol ; 2451: 547-556, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35505031

RESUMEN

Photodynamic therapy (PDT) is characterized by the local application of laser light, which activates a photosensitizer to lead to the formation of singlet oxygen and other toxic reactive oxygen species, to finally kill cells. Recently, photosensitizers have been conjugated to nanobodies to render PDT more selective to cancer cells. Nanobodies are the smallest naturally derived antibody fragments from heavy-chain antibodies that exist in animals of the Camelidae family. Indeed, we have shown that nanobody-targeted PDT can lead to extensive and selective tumor damage, and thus the subsequent step is to assess whether this damage can delay or even inhibit tumor growth in vivo. To evaluate the therapeutic efficacy of PDT, mouse models are mostly employed in which human tumors are grown subcutaneously in the flank of the animals. Although very useful, it has been suggested that these tumors are further away from their natural environment and that tumors developed in the organ or tissue of origin would be closer to the natural situation. Thus, this chapter describes the development of an orthotopic model of breast cancer and the application of nanobody-targeted PDT, for the assessment of the therapeutic efficacy.


Asunto(s)
Neoplasias de la Mama , Fotoquimioterapia , Anticuerpos de Dominio Único , Animales , Neoplasias de la Mama/tratamiento farmacológico , Femenino , Humanos , Luz , Ratones , Fármacos Fotosensibilizantes/farmacología , Fármacos Fotosensibilizantes/uso terapéutico , Anticuerpos de Dominio Único/farmacología , Anticuerpos de Dominio Único/uso terapéutico
8.
PLoS One ; 17(5): e0267989, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35511959

RESUMEN

The addition of supplemental light (SL) is an effective way to offset insufficient lighting. Although it is commonly believed that SL increases leaf photosynthesis and therefore improves yield and fruit flavor, the mechanism underlying the effects of SL on the photosystem II (PSII) apparatus remains unclear, and SL leads to high energy consumption. In order to save energy, we investigated the physiological status of the PSII apparatus, plant growth parameters and fruit parameters under two types of overhead SL with a low daily energy consumption of 0.0918 kWh m-2. The results showed that SL significantly increased the leaf chlorophyll content from full unfolding to yellowing. However, a remarkable increase in the absorption flux per cross-section (ABS/CS), the quantum yield of electron transport (φEo) and the performance index (PIabs) was observed only in a relatively short period of the leaf life cycle. SL also enhanced the fruit yield and quality. The obviously increased ΔVK and ΔVJ components of the chlorophyll fluorescence induction kinetic (OJIP) curve, along with the significantly decreased PIabs from days 40-60 after unfolding in the SL-treated groups, resulted in more rapid leaf aging and earlier fruit ripening compared with the control plants (CK). Therefore, an energy-friendly SL strategy can alter the physiological status of the PSII apparatus, affecting yield and fruit quality and maturity.


Asunto(s)
Lycopersicon esculentum , Complejo de Proteína del Fotosistema II , Clorofila/farmacología , Luz , Lycopersicon esculentum/metabolismo , Fotosíntesis/fisiología , Complejo de Proteína del Fotosistema II/metabolismo , Hojas de la Planta/metabolismo
9.
Nat Chem ; 14(5): 487-488, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35513567

Asunto(s)
Luz , Catálisis
10.
J Biomed Opt ; 27(8)2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35534924

RESUMEN

SIGNIFICANCE: Monte Carlo (MC) methods have been applied for studying interactions between polarized light and biological tissues, but most existing MC codes supporting polarization modeling can only simulate homogeneous or multi-layered domains, resulting in approximations when handling realistic tissue structures. AIM: Over the past decade, the speed of MC simulations has seen dramatic improvement with massively parallel computing techniques. Developing hardware-accelerated MC simulation algorithms that can accurately model polarized light inside three-dimensional (3D) heterogeneous tissues can greatly expand the utility of polarization in biophotonics applications. APPROACH: Here, we report a highly efficient polarized MC algorithm capable of modeling arbitrarily complex media defined over a voxelated domain. Each voxel of the domain can be associated with spherical scatters of various radii and densities. The Stokes vector of each simulated photon packet is updated through photon propagation, creating spatially resolved polarization measurements over the detectors or domain surface. RESULTS: We have implemented this algorithm in our widely disseminated MC simulator, Monte Carlo eXtreme (MCX). It is validated by comparing with a reference central-processing-unit-based simulator in both homogeneous and layered domains, showing excellent agreement and a 931-fold speedup. CONCLUSION: The polarization-enabled MCX offers biophotonics community an efficient tool to explore polarized light in bio-tissues, and is freely available at http://mcx.space/.


Asunto(s)
Fotones , Programas Informáticos , Algoritmos , Simulación por Computador , Luz , Método de Montecarlo
11.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 39(2): 370-379, 2022 Apr 25.
Artículo en Chino | MEDLINE | ID: mdl-35523559

RESUMEN

There is a shared problem in current optical imaging technologies of how to obtain the optical parameters of biological tissues with complex profiles. In this work, an imaging system for obtaining the optical parameters of biological tissues with complex profile was presented. Firstly, Fourier transformation profilometry was used for obtaining the profile information of biological tissues, and then the difference of incident light intensity at different positions on biological tissue surface was corrected with the laws of illumination, and lastly the optical parameters of biological tissues were achieved with the spatial frequency domain imaging technique. Experimental results indicated the proposed imaging system could obtain the profile information and the optical parameters of biological tissues accurately and quickly. For the slab phantoms with height variation less than 30 mm and angle variation less than 40º, the maximum relative errors of the profile uncorrected optical parameters were 46.27% and 72.18%, while the maximum relative errors of the profile corrected optical parameters were 6.89% and 10.26%. Imaging experiments of a face-like phantom and a human's prefrontal lobe were performed respectively, which demonstrated the proposed imaging system possesses clinical application value for the achievement of the optical parameters of biological tissues with complex profiles. Besides, the proposed profile corrected method can be used to combine with the current optical imaging technologies to reduce the influence of the profile information of biological tissues on imaging quality.


Asunto(s)
Diagnóstico por Imagen , Luz , Humanos , Imagen Óptica , Fantasmas de Imagen
12.
Anal Methods ; 14(16): 1571-1578, 2022 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-35403643

RESUMEN

Chemically and biologically modified substrates for single-cell patterning have been studied extensively, but physically modified structures for single-cell patterning still need further study. In this paper, physically modified silicon nanostructures were introduced to study their effect on SHSY5Y cells. Double-beam double exposure laser interference lithography combined with metal-assisted etching (MACE) was used to fabricate the physically modified silicon nanostructures. It was found that the cells on the gratings stretched and grew orderly along the grating with a small cell area and almost the same cell length compared with those on the Si wafer (control group). While on the grids, the cells were round with limited spreading, grew independently and had the smallest cell area and cell length. Moreover, the localization ratio of cells adhered onto the areas of nanopillars in the grid structures with different periods has been investigated. The results suggest that the physically modified grid silicon nanostructures can regulate the single-cell localization growth and the rational design of substrate structures can maximize the single-cell localization ratio. The findings provide guidance for the design of physically modified nanostructures and regulating single cell patterning, and a better understanding of single-cell localized growth.


Asunto(s)
Nanoestructuras , Silicio , Luz , Nanoestructuras/química , Nanotecnología/métodos , Impresión , Silicio/química
13.
Anal Methods ; 14(16): 1638-1645, 2022 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-35416194

RESUMEN

A modified mesh button sample holder is characterized by examining the effects of multiple absorption path lengths on infrared spectra. Unlike transmission cells, which are designed to provide a single radiation penetrating distance, reflections by the button stainless-steel mesh result in a wide distribution of absorption path lengths. Consequently, detector signals represent radiation traversing different distances through the sample. Higher absorptivity bands are measured with shorter effective path lengths than lower absorptivity bands. Therefore, band intensity ratios in measured infrared spectra differ from their relative absorptivities. In addition, overlapping band shapes are retained in spectral regions that would be opaque in transmission cell measurements. Wavenumber dependent effective path lengths can be systematically and reproducibly varied by changing the volume of liquid added to the button reservoir. Although Beer's law is not applicable, absorbance is proportional to concentration when sample volumes are constant, facilitating quantitative analyses.


Asunto(s)
Luz
14.
Carbohydr Polym ; 287: 119328, 2022 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-35422276

RESUMEN

Although chitosan is the second most abundant natural polymer on earth, with a wide range of biomaterial applications, its poor water solubility limits general printing process. We selected water-soluble methacrylated glycol chitosan (MeGC) as an alternative and prepared a MeGC-based MG-63 cell-laden bioink for 3D printing using a visible light curing system. Optimal cell-laden 3D printing of MeGC was completed at 3% using 12 µM of riboflavin as a photoinitiator under an irradiation for 70 s, a 26-gauge nozzle, a pneumatic pressure of 120 kPa, and a printing speed of 6 mm/s, as confirmed by printability, protein adsorption, cell viability, cell proliferation, and osteogenic capability. In addition, in vitro tests showed that MeGC-70 has a viability above 92%, a proliferation above 96%, and a hemolysis level below 2%. The results demonstrate the potential for MeGC-70 bioinks and 3D printed scaffolds to be used as patient-specific scaffolds for bone regeneration purposes.


Asunto(s)
Quitosano , Humanos , Luz , Impresión Tridimensional , Ingeniería de Tejidos/métodos , Andamios del Tejido , Agua
16.
Nat Commun ; 13(1): 1850, 2022 Apr 06.
Artículo en Inglés | MEDLINE | ID: mdl-35387971

RESUMEN

Genetically-encoded biosensors based on a single fluorescent protein are widely used to visualize analyte levels or enzymatic activities in cells, though usually to monitor relative changes rather than absolute values. We report photochromism-enabled absolute quantification (PEAQ) biosensing, a method that leverages the photochromic properties of biosensors to provide an absolute measure of the analyte concentration or activity. We develop proof-of-concept photochromic variants of the popular GCaMP family of Ca2+ biosensors, and show that these can be used to resolve dynamic changes in the absolute Ca2+ concentration in live cells. We also develop intermittent quantification, a technique that combines absolute aquisitions with fast fluorescence acquisitions to deliver fast but fully quantitative measurements. We also show how the photochromism-based measurements can be expanded to situations where the absolute illumination intensities are unknown. In principle, PEAQ biosensing can be applied to other biosensors with photochromic properties, thereby expanding the possibilities for fully quantitative measurements in complex and dynamic systems.


Asunto(s)
Técnicas Biosensibles , Técnicas Biosensibles/métodos , Transferencia Resonante de Energía de Fluorescencia , Colorantes Fluorescentes , Ionóforos , Luz , Proteínas
18.
Molecules ; 27(7)2022 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-35408697

RESUMEN

Preclassification of raw infrared spectra has often been neglected in scientific literature. Separating spectra of low spectral quality, due to low signal-to-noise ratio, presence of artifacts, and low analyte presence, is crucial for accurate model development. Furthermore, it is very important for sparse data, where it becomes challenging to visually inspect spectra of different natures. Hence, a preclassification approach to separate infrared spectra for sparse data is needed. In this study, we propose a preclassification approach based on Multiplicative Signal Correction (MSC). The MSC approach was applied on human and the bovine knee cartilage broadband Fourier Transform Infrared (FTIR) spectra and on a sparse data subset comprising of only seven wavelengths. The goal of the preclassification was to separate spectra with analyte-rich signals (i.e., cartilage) from spectra with analyte-poor (and high-matrix) signals (i.e., water). The human datasets 1 and 2 contained 814 and 815 spectra, while the bovine dataset contained 396 spectra. A pure water spectrum was used as a reference spectrum in the MSC approach. A threshold for the root mean square error (RMSE) was used to separate cartilage from water spectra for broadband and the sparse spectral data. Additionally, standard noise-to-ratio and principle component analysis were applied on broadband spectra. The fully automated MSC preclassification approach, using water as reference spectrum, performed as well as the manual visual inspection. Moreover, it enabled not only separation of cartilage from water spectra in broadband spectral datasets, but also in sparse datasets where manual visual inspection cannot be applied.


Asunto(s)
Luz , Agua , Animales , Bovinos , Humanos , Análisis de Componente Principal , Espectroscopía Infrarroja por Transformada de Fourier/métodos
19.
Molecules ; 27(7)2022 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-35408707

RESUMEN

In the current study, Bismuth molybdate was synthesized using simple co-precipitation procedure, and their characterization was carried out by various methods such as FT-IR, SEM, and P-XRD. Furthermore, the photocatalytic degradation of Orange G (ORG) dye using synthesized catalyst under visible light irradiation was studied. Response surface Method was used for the optimization of process variables and degradation kinetics evaluated by modeling of experimental data. Based on the experimental design outcomes, the first-order model was proven as a practical correlation between selected factors and response. Further ANOVA analysis has revealed that only two out of six factors have a significant effect on ORG degradation, however ORG concentration and irradiation time indicated the significant effects sequentially. Maximum ORG degradation of approximately 96% was achieved by keeping process parameters in range, such as 1 g L-1 loading of catalyst, 50 mg L-1 concentration of ORG, 1.4 mol L-1 concentration of H2O2 at pH 7 and a temperature of 30 °C. Kinetics of ORG degradation followed the pseudo first order, and almost complete degradation was achieved within 8 h. The effectiveness of the Bi2MoO6/H2O2 photo-Fenton system in degradation reactions is due to the higher number of photo-generated e- available on the catalyst surface as a result of their ability to inhibit recombination of e- and h+ pair.


Asunto(s)
Bismuto , Peróxido de Hidrógeno , Compuestos Azo , Bismuto/química , Catálisis , Luz , Molibdeno , Espectroscopía Infrarroja por Transformada de Fourier
20.
Sci Rep ; 12(1): 6580, 2022 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-35449377

RESUMEN

The development of effective pathogen reduction strategies is required due to the rise in antibiotic-resistant bacteria and zoonotic viral pandemics. Photodynamic inactivation (PDI) of bacteria and viruses is a potent reduction strategy that bypasses typical resistance mechanisms. Naturally occurring riboflavin has been widely used in PDI applications due to efficient light-induced reactive oxygen species (ROS) release. By rational design of its core structure to alter (photo)physical properties, we obtained derivatives capable of outperforming riboflavin's visible light-induced PDI against E. coli and a SARS-CoV-2 surrogate, revealing functional group dependency for each pathogen. Bacterial PDI was influenced mainly by guanidino substitution, whereas viral PDI increased through bromination of the flavin. These observations were related to enhanced uptake and ROS-specific nucleic acid cleavage mechanisms. Trends in the derivatives' toxicity towards human fibroblast cells were also investigated to assess viable therapeutic derivatives and help guide further design of PDI agents to combat pathogenic organisms.


Asunto(s)
COVID-19 , Fotoquimioterapia , Bacterias , Escherichia coli , Humanos , Luz , Fármacos Fotosensibilizantes/química , Especies Reactivas de Oxígeno/farmacología , Riboflavina/farmacología , SARS-CoV-2
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