Zeitschriftenartikel: „In vivo absorption spectroscopy“

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Furukawa, Hiromitsu, und Takashi Fukuda. „In vivo absorption spectroscopy for absolute measurement“. Biomedical Optics Express 3, Nr. 10 (18.09.2012): 2587. http://dx.doi.org/10.1364/boe.3.002587.

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Taroni, Paola, Antonio Pifferi, Alessandro Torricelli, Daniela Comelli und Rinaldo Cubeddu. „In vivo absorption and scattering spectroscopy of biological tissues“. Photochemical & Photobiological Sciences 2, Nr. 2 (2003): 124. http://dx.doi.org/10.1039/b209651j.

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Klinteberg, Claes af, Antonio Pifferi, Stefan Andersson-Engels, Rinaldo Cubeddu und Sune Svanberg. „In vivo absorption spectroscopy of tumor sensitizers with femtosecond white light“. Applied Optics 44, Nr. 11 (10.04.2005): 2213. http://dx.doi.org/10.1364/ao.44.002213.

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Park, Soomin, Collin J. Steen, Alexandra L. Fischer und Graham R. Fleming. „Snapshot transient absorption spectroscopy: toward in vivo investigations of nonphotochemical quenching mechanisms“. Photosynthesis Research 141, Nr. 3 (24.04.2019): 367–76. http://dx.doi.org/10.1007/s11120-019-00640-x.

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Colombo, L., M. Pagliazzi, S. Konugolu Venkata Sekar, D. Contini, T. Durduran und A. Pifferi. „In vivo time-domain diffuse correlation spectroscopy above the water absorption peak“. Optics Letters 45, Nr. 13 (17.06.2020): 3377. http://dx.doi.org/10.1364/ol.392355.

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Kezic, S. „Methods for measuring in-vivo percutaneous absorption in humans“. Human & Experimental Toxicology 27, Nr. 4 (April 2008): 289–95. http://dx.doi.org/10.1177/0960327107085825.

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In-vivo human data on percutaneous absorption are scarce, although they are indispensable for health risk assessment of dermal exposure. In addition, they are considered to be the gold standard for the evaluation of in-vitro systems as well as predictive mathematical models. Dermal absorption in vivo can be assessed using different approaches. The most used methods for determination of in-vivo dermal absorption are the measurement of the parent chemical and/or its metabolite level in biological material, the microdialysis technique and stratum corneum tape stripping. Recently, the non-invasive spectrophotometric methods based on infrared and Raman spectroscopy showed themselves as promising tools for studying percutaneous absorption though these approaches are still in their developmental stages and requires further optimization and validation. The aim of this article is to review different methods for determination of percutaneous absorption in vivo in humans. The advantages and limitations are discussed with respect to generating data for comparison with in-vitro or predictive mathematical models or health risk assessment of chemicals. Furthermore, the importance of the volunteer experiments in generating relevant data for human risk assessment as well as for the development and implementation of biological monitoring in occupational settings will be addressed.

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Piantadosi, C. A. „Spectrophotometry of b-type cytochromes in rat brain in vivo and in vitro“. American Journal of Physiology-Cell Physiology 256, Nr. 4 (01.04.1989): C840—C848. http://dx.doi.org/10.1152/ajpcell.1989.256.4.c840.

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Terminal oxidase inhibitors such as cyanide (CN) and carbon monoxide (CO) produce different absorption changes in the intact brain, suggesting different mitochondrial responses to the inhibitors. In the present study, the nature of the cytochromes involved in CO and CN responses in vivo was investigated by low-temperature spectroscopy of rat brain, frozen in situ, and of preparations of brain homogenate and isolated mitochondria. Comparison of the spectra from different preparations at the high resolution afforded by low-temperature spectroscopy indicated that absorption responses to CO in vivo originated from mitochondrial b cytochromes. Further detailed spectral analysis of mitochondrial preparations revealed three CN-insensitive b cytochromes in nonsynaptic brain mitochondria; one cytochrome could be reduced by succinate in the presence of CN, the second could be reduced by succinate plus ATP, and the third could be reduced only by anaerobiosis. The spectral characteristics of the mitochondrial b cytochromes, when compared with spectra from CO-exposed brain tissue frozen in situ, strongly implicated the energy-dependent cytochrome b in the oxidation-reduction (redox) responses caused by CO in vivo.

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Nishidate, Izumi, Tomohiro Ishizuka, Afrina Mustari, Keiichiro Yoshida, Satoko Kawauchi, Shunichi Sato und Manabu Sato. „Evaluation of Cerebral Hemodynamics and Tissue Morphology of In Vivo Rat Brain Using Spectral Diffuse Reflectance Imaging“. Applied Spectroscopy 71, Nr. 5 (05.07.2016): 866–78. http://dx.doi.org/10.1177/0003702816657569.

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We investigated a quantitative imaging of reduced scattering coefficients μs’( λ) and the absorption coefficients μa( λ) of in vivo cortical tissues in the range from visible to near-infrared (NIR) wavelengths based on diffuse reflectance spectral imaging technique. In this method, diffuse reflectance images of in vivo cortical tissue are acquired at nine wavelengths (500, 520, 540, 560, 570, 580, 600, 730, and 760 nm). A multiple regression analysis aided by the Monte Carlo simulation for the absorbance spectra is then utilized to estimate the optical coefficients of cortical tissue. This analysis calculates the concentration of oxygenated hemoglobin and that of deoxygenated hemoglobin, the scattering amplitude a and the scattering power b. The spectrum of absorption coefficient is deduced from the estimated concentrations of oxygenated hemoglobin and deoxygenated hemoglobin. The spectrum of reduced scattering coefficient is determined by the estimated scattering amplitude and scattering power. The particle size distribution of microstructure is calculated from the estimated scattering power b for evaluating the morphological change in brain tissue quantitatively. Animal experiments with in vivo exposed brain of rats demonstrated that the responses of the absorption properties to hyperoxic and anoxic conditions are in agreement with the expected well-known cortical hemodynamics. The average particle size was significantly reduced immediately after the onset of anoxia and then it was changed into an increase, which implied the swelling and shrinkage of the cellular and subcellular structures induced by loss of tissue viability in brain tissue.

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Suzuki, Hiroshi, Masatsugu Niwayama, Toshitaka Yamakawa, Masaki Ohkubo, Ryotaro Kime und Toshihito Katsumura. „Simultaneous Determination of Absorption Coefficients for Skin and Muscle Tissues Using Spatially Resolved Measurements“. Advanced Materials Research 222 (April 2011): 309–12. http://dx.doi.org/10.4028/www.scientific.net/amr.222.309.

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We present a method for simultaneous measurement of optical absorption coefficients for skin (μas) and muscle (μam) tissues using spatially resolved near-infrared spectroscopy (SRS). A novel calculation algorithm was developed to determine the absorption coefficients of superficial and deep layers within a three-layered structure using Monte Carlo simulation. A method for measuring the skin and muscle absorption coefficients was proposed based on this algorithm. In vitro experiments with tissue-like phantom and in vivo tests were performed using the SRS system with four separate detectors. The results show that the absorption coefficients for both skin and muscle tissues were obtained accurately.

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Wu, Zhi Ying, und Nan Nan Gai. „Independent Component Analysis of Multiple-Component Gaseous Photoacoustic Spectroscopy to Determine Feature Absorption“. Advanced Materials Research 518-523 (Mai 2012): 1544–51. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.1544.

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A blind source separation model out of statistical information principle is applied to “decode” multi-gas photoacoustic spectroscopy from mixing signal into a couple of single independent component based on samples from a given detection experiment and A FastICA algorithm with used in the mode is introduced to separate the spectroscopy of low molecule mass by a feature extraction or to track that of higher-mass volatile molecule by a pattern recognition, such as acetone or its similar-species molecules. The research has exhibited its glamour by successfully extracting ammonia feature absorption in the real-time detection of breath ammonia in vivo.

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Winter, Patrick M., Viswanathan Seshan, Janice D. Makos, A. Dean Sherry, Craig R. Malloy und Navin Bansal. „Quantitation of intracellular [Na+] in vivo by using TmDOTP5− as an NMR shift reagent and extracellular marker“. Journal of Applied Physiology 85, Nr. 5 (01.11.1998): 1806–12. http://dx.doi.org/10.1152/jappl.1998.85.5.1806.

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A method is presented to measure the absolute concentration of intracellular Na+([Na+]i) in vivo by using interleaved 23Na- and 31P-nuclear magnetic resonance (NMR) spectroscopy and TmDOTP5− as shift reagent and chemical marker of tissue extracellular space (ECS). The technique was used to determine [Na+]iand relative ECS in livers of control rats (21 ± 3 and 0.11 ± 0.02 mM, respectively) and in rats exposed to carbon tetrachloride (103 ± 29 and 0.23 ± 0.03 mM, respectively). The NMR measurements were confirmed independently on excised tissue samples by using atomic absorption spectroscopy. The results confirm that TmDOTP5− can be used as a combined cation shift reagent and ECS marker, thereby allowing quantitation of [Na+]iin vivo by NMR.

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Broding, Horst Christoph, André van der Pol, Johanna de Sterke, Christian Monsé, Manigé Fartasch und Thomas Brüning. „In vivo Monitoring of epidermal absorption of hazardous substances by confocal Raman micro-spectroscopy“. JDDG: Journal der Deutschen Dermatologischen Gesellschaft 9, Nr. 8 (24.03.2011): 618–27. http://dx.doi.org/10.1111/j.1610-0387.2011.07657.x.

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Yu, Bing, Justin Y. Lo, Thomas F. Kuech, Gregory M. Palmer, Janelle E. Bender und Nirmala Ramanujam. „Cost-effective diffuse reflectance spectroscopy device for quantifying tissue absorption and scattering in vivo“. Journal of Biomedical Optics 13, Nr. 6 (2008): 060505. http://dx.doi.org/10.1117/1.3041500.

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Xia, Z. F., J. W. Horton, P. Y. Zhao, E. E. Babcock, A. D. Sherry und C. R. Malloy. „Effects of ischemia on intracellular sodium and phosphates in the in vivo rat liver“. Journal of Applied Physiology 81, Nr. 3 (01.09.1996): 1395–403. http://dx.doi.org/10.1152/jappl.1996.81.3.1395.

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Metabolic factors that influence the transition form reversible to irreversible ischemic injury were studied in the rat liver in vivo with 31P-nuclear magnetic resonance (NMR) spectroscopy. Hepatic ischemia for 15, 35, or 65 min was produced by occlusion of the hepatic artery and portal vein in rats. Ischemia caused a rapid decrease in the ATP concentration ([ATP])-to-P(i) concentration ratio and pH within 5 min, but there was little change in these variables detectable by 31P-NMR with longer periods of ischemia. After reperfusion, the [ATP] and P(i) concentration returned toward normal values in livers exposed to 15 or 35 min of ischemia, but 65 min of ischemia were associated with only modest recovery in [ATP], and the [ATP] later decreased. Because the 31P-NMR spectrum was similar after brief compared with prolonged ischemia, it appears that neither ATP depletion, P(i) accumulation, nor acidosis predicts metabolic recovery. Hepatic intracellular NA+ was also measured in separate groups of animals by 23Na-NMR in the presence of a shift agent, thulium (III) 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis (methylene-phosphonate) (TmDOTP5-), and by atomic absorption spectroscopy. Under baseline conditions, the concentration of intracellular Na+ was 15.2 mM by atomic absorption spectroscopy and 16.5 mM by 23Na-NMR. Although the 31P-NMR spectrum responded very rapidly to the onset of ischemia, intracellular Na+ concentration measured by 23Na-NMR increased gradually but steadily at approximately 1.0 mM/min during early (up to 15 min) ischemia. These observations demonstrate that a rise in intracellular Na+ does occur early ischemia, that TmDOTP5- can be applied in vivo for analysis of intracellular Na+ in the ischemic liver, and that 31P-NMR spectroscopy is very sensitive to early ischemic injury.

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Wang, Ming Bo, Yu Bao Li, Feng Lan Xu, Gang Zhou und Lin Cheng. „Synthesis and Characterization of n-HA/PVA/Gel Composite“. Key Engineering Materials 330-332 (Februar 2007): 471–74. http://dx.doi.org/10.4028/www.scientific.net/kem.330-332.471.

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A unique composite consisted of nano-hydroxyapatite (n-HA), poly (vinyl alcohol) (PVA) and gelatin (Gel), was prepared and characterized by Fourier transform infrared absorption spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and burning test. The homogenicity of the composite was evaluated, and the presence of interior chemical bond was confirmed and discussed. Mechanical strength and water absorption of the prepared composite were investigated, respectively. The results show that n-HA/PVA/Gel composite has good homogeneity, similar mechanical properties to natural cartilage and excellent in vivo biocompatibility.

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Luo, Si Te, Guo Qiang Chen, Ruo Fei Cui, Wei Wei Zhou, Li Qian Lu und Zeng Yong Li. „Noninvasive Alcohol Detection Using Near-Infrared Spectroscopy Based on Partial Least Squares and Monte-Carlo“. Applied Mechanics and Materials 229-231 (November 2012): 1308–11. http://dx.doi.org/10.4028/www.scientific.net/amm.229-231.1308.

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The objective of this study was to assess the feasibility of noninvasive alcohol testing in vivo with near-infrared (NIR) spectroscopy. The suitable distance between light source and detector was determined by Monte-Carlo simulation. The NIR spectra signals of alcohol in vitro and in vivo were measured, and the blood alcohol concentration (BAC) was measured with breath test method. Wavelet de-noising and partial least squares (PLS) method were used to establish the quantitative calibration model of alcohol. The results indicate that alcohol spectra had two absorption peaks at range of 2200nm～2400nm. The optimal principal component number of PLS model is 3, RMSEP=9.29, MREP=3.5%，R=0.9802. The model has good prediction accuracy. NIRS might provide a new method to the measurement of alcohol in vivo.

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Rosenbach, Hannah, Eva Walla, George E. Cutsail, James A. Birrell, Marina Pascual-Ortiz, Serena DeBeer, Ursula Fleig und Ingrid Span. „The Asp1 pyrophosphatase from S. pombe hosts a [2Fe-2S]2+ cluster in vivo“. JBIC Journal of Biological Inorganic Chemistry 26, Nr. 1 (Februar 2021): 93–108. http://dx.doi.org/10.1007/s00775-020-01840-w.

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AbstractThe Schizosaccharomyces pombe Asp1 protein is a bifunctional kinase/pyrophosphatase that belongs to the highly conserved eukaryotic diphosphoinositol pentakisphosphate kinase PPIP5K/Vip1 family. The N-terminal Asp1 kinase domain generates specific high-energy inositol pyrophosphate (IPP) molecules, which are hydrolyzed by the C-terminal Asp1 pyrophosphatase domain (Asp1365−920). Thus, Asp1 activities regulate the intracellular level of a specific class of IPP molecules, which control a wide number of biological processes ranging from cell morphogenesis to chromosome transmission. Recently, it was shown that chemical reconstitution of Asp1371−920 leads to the formation of a [2Fe-2S] cluster; however, the biological relevance of the cofactor remained under debate. In this study, we provide evidence for the presence of the Fe–S cluster in Asp1365−920 inside the cell. However, we show that the Fe–S cluster does not influence Asp1 pyrophosphatase activity in vitro or in vivo. Characterization of the as-isolated protein by electronic absorption spectroscopy, mass spectrometry, and X-ray absorption spectroscopy is consistent with the presence of a [2Fe-2S]2+ cluster in the enzyme. Furthermore, we have identified the cysteine ligands of the cluster. Overall, our work reveals that Asp1 contains an Fe–S cluster in vivo that is not involved in its pyrophosphatase activity.

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Adeleye, O. A., O. A. Bamiro, L. G. Bakre, A. O. Badru, O. A. Balogun-Agbaje, A. Olusola und O. E. Adejumo. „In Vivo Anti-Inflammatory Assessment of a Topical Formulation Containing Ehretia Cymosa Extract Mediated-Silver Nanoparticles“. Nigerian Journal of Pharmaceutical Research 17, Nr. 2 (11.02.2022): 179–88. http://dx.doi.org/10.4314/njpr.v17i2.4.

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Background: Silver nanoparticles (SNP) are the most preferred and most often used metallic nanoparticles in biomedical studies. However, there are only few studies on its application in topical drug delivery design. Objectives: This study was carried out to design topical ointments containing n-hexane and methanol Ehretia cymosa leaf extracts mediated-silver nanoparticles for the treatment of inflammation.Methods: Silver nitrate was reacted with n-hexane and methanol extracts of Ehretia cymosa leaf to synthesize SNP used in the formulation of an ointment. The SNP was characterized by visual observation, UV–visible spectroscopy, atomic absorption spectroscopy and FTIR spectroscopy. The physical characteristics of the ointment and spreadability were evaluated. Inflammation was inflicted by carrageenan-induced paw acute edema method in albino rats. The linear paw circumference was measured hourly after application of the ointment.Results: There was colour change as the synthesis progresses. The absorption peak of n-hexane SNP (N-SNP) and methanol SNP (M-SNP) was 450 nm and 430 nm respectively. The ointments were easy to administer with satisfactory spreadability but difficult to wash off. Ointments containing SNP had significantly higher activity (p < 0.05) than the crude extract and ointments containing M-SNP had significantly higher activity (p < 0.05) than ointments containing N-SNP.Conclusion: The anti-inflammatory activity of ointment containing SNP synthesized with methanol extract is significantly higher compared to ointment formulations containing silver nanoparticle synthesized with n-hexane extract and the reference drug (diclofenac).

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Lee, Jangwoen, Naglaa El-Abaddi, Andrew Duke, Albert E. Cerussi, Matthew Brenner und Bruce J. Tromberg. „Noninvasive in vivo monitoring of methemoglobin formation and reduction with broadband diffuse optical spectroscopy“. Journal of Applied Physiology 100, Nr. 2 (Februar 2006): 615–22. http://dx.doi.org/10.1152/japplphysiol.00424.2004.

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We present noninvasive, quantitative in vivo measurements of methemoglobin formation and reduction in a rabbit model using broadband diffuse optical spectroscopy (DOS). Broadband DOS combines multifrequency frequency-domain photon migration (FDPM) with time-independent near infrared (NIR) spectroscopy to quantitatively measure bulk tissue absorption and scattering spectra between 600 nm and 1,000 nm. Tissue concentrations (denoted by brackets) of methemoglobin ([MetHb]), deoxyhemoglobin ([Hb-R]), and oxyhemoglobin ([HbO2]) were determined from absorption spectra acquired in “real time” during nitrite infusions in nine pathogen-free New Zealand White rabbits. As little as 30 nM [MetHb] changes were detected for levels of [MetHb] that ranged from 0.80 to 5.72 μM, representing 2.2 to 14.9% of the total hemoglobin content (%MetHb). These values agreed well with on-site ex vivo cooximetry data ( r2 = 0.902, P < 0.0001, n = 4). The reduction of MetHb to functional hemoglobins was also carried out with intravenous injections of methylene blue (MB). As little as 10 nM changes in [MB] were detectable at levels of up to 150 nM in tissue. Our results demonstrate, for the first time, the ability of broadband DOS to noninvasively quantify real-time changes in [MetHb] and four additional chromophore concentrations ([Hb-R], [HbO2], [H2O], and [MB]) despite significant overlapping spectral features. These techniques are expected to be useful in evaluating dynamics of drug delivery and therapeutic efficacy in blood chemistry, human, and preclinical animal models.

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Huang, Yimei, Zhenguo Wu, Harvey Lui, Jianhua Zhao, Shusen Xie und Haishan Zeng. „Precise closure of single blood vessels via multiphoton absorption–based photothermolysis“. Science Advances 5, Nr. 5 (Mai 2019): eaan9388. http://dx.doi.org/10.1126/sciadv.aan9388.

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We report a novel approach to selectively close single blood vessels within tissue using multiphoton absorption–based photothermolysis (multiphoton photothermolysis) without the need of exogenous agents. The treatment process is monitored by in vivo reflectance confocal microscopy in real time. Closure of single targeted vessels of varying sizes ranging from capillaries to venules was demonstrated. We also demonstrated that deeply situated blood vessels could be closed precisely while preserving adjacent overlying superficial blood vessels. In vivo confocal Raman spectroscopy of the treatment sites confirmed vessel closure as being mediated by local coagulative damage. Partial vessel occlusion could be achieved, and it is accompanied by increased intravascular blood cell speed. Multiphoton photothermolysis under real-time reflectance confocal imaging guidance provides a novel precision medicine approach for noninvasive, precise microsurgery treatment of vascular diseases on a per-vessel/per-lesion basis. The method could also be used for building ischemic stroke models for basic biology study.

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Batista, Eucilene K., Lidiane M. A. de Lima, Dayane A. Gomes, Debbie C. Crans, Wagner E. Silva, Mônica F. Belian und Eduardo C. Lira. „Dexamethasone-Induced Insulin Resistance Attenuation by Oral Sulfur–Oxidovanadium(IV) Complex Treatment in Mice“. Pharmaceuticals 17, Nr. 6 (10.06.2024): 760. http://dx.doi.org/10.3390/ph17060760.

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Vanadium compounds are known to exert insulin-enhancing activity, normalize elevated blood glucose levels in diabetic subjects, and show significant activity in models of insulin resistance (IR). Faced with insulin resistance, the present work investigates the antidiabetic performance of a known oxidovanadium(IV)-based coordination compound—[VIVO(octd)]—and effects associated with glucocorticoid-induced insulin resistance in mice. The effects of [VIVO(octd)] were evaluated in a female Swiss mice model of insulin resistance induced by seven days of dexamethasone treatment in comparison with groups receiving metformin treatment. Biological assays such as hematological, TyG index, hepatic lipids, glycogen, oxidative stress in the liver, and oral glucose tolerance tests were evaluated. [VIVO(octd)] was characterized with 51V NMR, infrared spectroscopy (FTIR), electron paramagnetic resonance (EPR), electronic absorption spectroscopy, and mass spectrometry (ESI–FT–MS). The [VIVO(octd)] oral treatment (50 mg/kg) had an antioxidant effect, reducing 50% of fast blood glucose (p < 0.05) and 25% of the TyG index, which is used to estimate insulin resistance (p < 0.05), compared with the non-treated group. The oxidovanadium–sulfur compound is a promising antihyperglycemic therapeutic, including in cases aggravated by insulin resistance induced by glucocorticoid treatment.

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Di Sieno, Laura, Alberto Dalla Mora, Alessandro Torricelli, Lorenzo Spinelli, Rebecca Re, Antonio Pifferi und Davide Contini. „A Versatile Setup for Time-Resolved Functional Near Infrared Spectroscopy Based on Fast-Gated Single-Photon Avalanche Diode and on Four-Wave Mixing Laser“. Applied Sciences 9, Nr. 11 (10.06.2019): 2366. http://dx.doi.org/10.3390/app9112366.

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In this paper, a time-domain fast gated near-infrared spectroscopy system is presented. The system is composed of a fiber-based laser providing two pulsed sources and two fast gated detectors. The system is characterized on phantoms and was tested in vivo, showing how the gating approach can improve the contrast and contrast-to-noise-ratio for detection of absorption perturbation inside a diffusive medium, regardless of source-detector separation.

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Fabiano, Angela, Elisa Brilli, Letizia Mattii, Lara Testai, Stefania Moscato, Valentina Citi, Germano Tarantino und Ylenia Zambito. „Ex Vivo and in Vivo Study of Sucrosomial® Iron Intestinal Absorption and Bioavailability“. International Journal of Molecular Sciences 19, Nr. 9 (12.09.2018): 2722. http://dx.doi.org/10.3390/ijms19092722.

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The present study aimed to demonstrate that Sideral® RM (SRM, Sucrosomial® Raw Material Iron) is transported across the excised intestine via a biological mechanism, and to investigate the effect that this transport route may produce on oral iron absorption, which is expected to reduce the gastrointestinal (GI) side effects caused by the bioavailability of non-absorbed iron. Excised rat intestine was exposed to fluorescein isothiocyanate (FITC)-labeled SRM in Ussing chambers followed by confocal laser scanning microscopy to look for the presence of fluorescein-tagged vesicles of the FITC-labeled SRM. To identify FITC-labeled SRM internalizing cells, an immunofluorescence analysis for macrophages and M cells was performed using specific antibodies. Microscopy analysis revealed the presence of fluorescein positive particulate structures in tissues treated with FITC-labeled SRM. These structures do not disintegrate during transit, and concentrate in macrophage cells. Iron bioavailability was assessed by determining the time-course of Fe3+ plasma levels. As references, iron contents in liver, spleen, and bone marrow were determined in healthy rats treated by gavage with SRM or ferric pyrophosphate salt (FP). SRM significantly increased both area under the curve (AUC) and clearance maxima (Cmax) compared to FP, thus increasing iron bioavailability (AUCrel = 1.8). This led to increased iron availability in the bone marrow at 5 h after single dose gavage.

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Rao, Y. Madhusudan, Chopparapu K S C, P. Chinna Reddy und Narender Doodipala. „Development of Promethazine Hydrochloride Mucoadhesive Patches for Buccal Delivery: In vitro, Ex vivo and In vivo Characterization“. International Journal of Pharmaceutical Sciences and Nanotechnology 5, Nr. 2 (31.08.2012): 1697–705. http://dx.doi.org/10.37285/ijpsn.2012.5.2.5.

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Promethazine hydrochloride (PMZ HCl), an antiemetic, undergoes extensive first-pass metabolism (bioavailability 25%). The purpose of the present investigation was to develop mucoadhesive patches for transbuccal delivery of PMZ HCl using solvent casting technique with Hydroxy ethyl cellulose (Natrosol 250 E) and hydroxylpropyl methyl cellulose as mucoadhesive polymers and propylene glycol as the plasticizer and evaluate their physicochemical characteristics, in vitro drug release, moisture absorption, surface pH, mechanical properties, in vitro bioadhesion, in vivo residence time, and ex vivo drug permeation through porcine buccal membranes from optimized buccal patch and stability studies. The physicochemical interaction between PMZ HCl and polymers was investigated by Fourier Transform Infrared Spectroscopy. Ex vivo drug permeation through porcine buccal membrane was performed and 83.7% of the drug permeated in 6 hours with flux 0.19 mg h–1cm–2. The optimized formulation AA4 showed maximum drug release (98%) in 6 hours in the Higuchi model release profile. Moisture absorption, surface pH, tensile strength, elongation at break, peak detachment force and work of adhesion values of the optimized formulation were found to be 68.1%, pH 6.7, 12.3 kg/mm2, 69.2 % mm2, 7.5 N and 2.73 mJ respectively. Formulation AA4 showed 77.6% of the drug permeated through porcine buccal membrane in 6 hours and flux calculated to be 0.45 mg h–1cm–2. FTIR studies showed no evidence of interaction between the drug and polymers. In vivo mucoadhesive behaviour of the optimized formulation was studied in healthy human volunteers and subjective parameters were evaluated. The stability of the optimized formulation was studied and no significant changes were detected in drug content, in vitro release and ex vivo permeation after 6 months.

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Park, Soomin, Collin J. Steen, Dagmar Lyska, Alexandra L. Fischer, Benjamin Endelman, Masakazu Iwai, Krishna K. Niyogi und Graham R. Fleming. „Chlorophyll–carotenoid excitation energy transfer and charge transfer in Nannochloropsis oceanica for the regulation of photosynthesis“. Proceedings of the National Academy of Sciences 116, Nr. 9 (11.02.2019): 3385–90. http://dx.doi.org/10.1073/pnas.1819011116.

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Nonphotochemical quenching (NPQ) is a proxy for photoprotective thermal dissipation processes that regulate photosynthetic light harvesting. The identification of NPQ mechanisms and their molecular or physiological triggering factors under in vivo conditions is a matter of controversy. Here, to investigate chlorophyll (Chl)–zeaxanthin (Zea) excitation energy transfer (EET) and charge transfer (CT) as possible NPQ mechanisms, we performed transient absorption (TA) spectroscopy on live cells of the microalga Nannochloropsis oceanica. We obtained evidence for the operation of both EET and CT quenching by observing spectral features associated with the Zea S1 and Zea●+ excited-state absorption (ESA) signals, respectively, after Chl excitation. Knockout mutants for genes encoding either violaxanthin de-epoxidase or LHCX1 proteins exhibited strongly inhibited NPQ capabilities and lacked detectable Zea S1 and Zea●+ ESA signals in vivo, which strongly suggests that the accumulation of Zea and active LHCX1 is essential for both EET and CT quenching in N. oceanica.

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Wagner, W. D., und W. Waidelich. „Selective Observation of Chlorophyll c in Whole Cells of Diatoms by Resonant Raman Spectroscopy“. Applied Spectroscopy 40, Nr. 2 (Februar 1986): 191–96. http://dx.doi.org/10.1366/0003702864509574.

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A surface scanning technique was used to obtain resonant Raman spectra from chlorophylls in solution and in whole cells of diatoms at 80 K. When in vivo samples are excited at 457.9 nm, chlorophyll c becomes observable in the recorded Raman spectra, as shown by comparison with in vitro measurements. In the field of photosynthetic research this becomes Interesting, as chlorophyll c can hardly be detected in electronic absorption spectra from whole cells, even at low temperatures, because of its weak Q bands compared with other plant chlorophylls. Chl a spectra were obtained with the use of 441.6-nm excitation. Working with two-channel recording, we eliminated the solvent contribution from the Raman spectra of pigments in vitro. Moreover, the technique facilitates detection of Raman excitation profiles from pigment lines in vivo at low temperatures by use of a nonresonating reference in the second sample chamber.

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MORGAN, S. P., I. M. STOCKFORD, J. A. CROWE und B. R. HAYES-GILL. „OPTICAL IMAGING AND SPECTROSCOPY OF SUPERFICIAL TISSUE“. Journal of Innovative Optical Health Sciences 01, Nr. 01 (Juni 2008): 85–93. http://dx.doi.org/10.1142/s1793545808000091.

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An overview of three techniques developed by our group for imaging superficial tissue is presented. Firstly, a novel polarized light capillaroscope has been developed for imaging the microcirculation. The capillaroscope has been used to make in vivo measurements of sickle cell disorder sufferers with aim of monitoring the polymerization of sickled red blood cells. Secondly, hyperspectral imaging for measuring oxygen saturation is described. The accuracy of such measurements is affected by the non-linear relationship between scattering and absorption and it is demonstrated that polarization techniques can be used to make the relationship more linear, thus improving accuracy. Finally, the use of smart CMOS optical sensors for laser Doppler blood flowmetry is described. A 32 × 32 pixel imaging array with on-chip processing is described and the potential for full field laser Doppler blood flow imaging is demonstrated through measurement on blood flow of tissue before and after occlusion.

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Borycki, Dawid, Oybek Kholiqov und Vivek J. Srinivasan. „Reflectance-mode interferometric near-infrared spectroscopy quantifies brain absorption, scattering, and blood flow index in vivo“. Optics Letters 42, Nr. 3 (30.01.2017): 591. http://dx.doi.org/10.1364/ol.42.000591.

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Lee, David J., C. Tyler Burt und Ronald L. Koch. „Percutaneous Absorption of Flurbiprofen in the Hairless Rat Measured In Vivo Using 19F Magnetic Resonance Spectroscopy“. Journal of Investigative Dermatology 99, Nr. 4 (Oktober 1992): 431–34. http://dx.doi.org/10.1111/1523-1747.ep12616137.

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Kim, Ki-Hong, Sanghoon Jheon und Jong-Ki Kim. „In vivo skin absorption dynamics of topically applied pharmaceuticals monitored by fiber-optic diffuse reflectance spectroscopy“. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 66, Nr. 3 (März 2007): 768–72. http://dx.doi.org/10.1016/j.saa.2006.04.029.

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Finch, Anthony J., Jamie M. Benson, Patrick E. Donnelly und Peter A. Torzilli. „Light Absorptive Properties of Articular Cartilage, ECM Molecules, Synovial Fluid, and Photoinitiators as Potential Barriers to Light-Initiated Polymer Scaffolding Procedures“. CARTILAGE 10, Nr. 1 (18.06.2017): 82–93. http://dx.doi.org/10.1177/1947603517713815.

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Objective Many in vivo procedures to repair chondral defects use ultraviolet (UV)-photoinitiated in situ polymerization within the cartilage matrix. Chemical species that absorb UV light might reduce the effectiveness of these procedures by acting as light absorption barriers. This study evaluated whether any of the individual native biochemical components in cartilage and synovial fluid interfered with the absorption of light by common scaffolding photosensitizers. Materials UV-visible spectroscopy was performed on each major component of cartilage in solution, on bovine synovial fluid, and on four photosensitizers, riboflavin, Irgacure 2959, quinine, and riboflavin-5′-phosphate. Molar extinction and absorption coefficients were calculated at wavelengths of maximum absorbance and 365 nm. Intact articular cartilage was also examined. Results The individual major biochemical components of cartilage, Irgacure 2959, and quinine did not exhibit a significant absorption at 365 nm. Riboflavin and riboflavin-5′-phosphate were more effectual light absorbers at 365 nm, compared with the individual native species. Intact cartilage absorbed a significantly greater amount of UV light in comparison with the native species. Conclusion Our results indicate that none of the individual native species in cartilage will interfere with the absorption of UV light at 365 nm by these commonly used photoinitiators. Intact cartilage slices exhibited significant light absorption at 365 nm, while also having distinct absorbance peaks at wavelengths less than 300 nm. Determining the UV absorptive properties of the biomolecules native to articular cartilage and synovial fluid will aid in optimizing scaffolding procedures to ensure sufficient scaffold polymerization at a minimum UV intensity.

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Zalesskaya, G. A., L. G. Astaf’eva und L. E. Batai. „Thermal changes in the absorption spectra of blood with supravascular infrared laser irradiation in vivo“. Journal of Applied Spectroscopy 78, Nr. 4 (September 2011): 579–85. http://dx.doi.org/10.1007/s10812-011-9501-2.

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Rompel, A., R. M. Cinco, M. J. Latimer, A. E. McDermott, R. D. Guiles, A. Quintanilha, R. M. Krauss, K. Sauer, V. K. Yachandra und M. P. Klein. „Sulfur K-edge x-ray absorption spectroscopy: A spectroscopic tool to examine the redox state of S-containing metabolites in vivo“. Proceedings of the National Academy of Sciences 95, Nr. 11 (26.05.1998): 6122–27. http://dx.doi.org/10.1073/pnas.95.11.6122.

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Cabello-Alvarado, C., M. Andrade-Guel, M. Pérez-Alvarez, G. Cadenas-Pliego, Dora A. Cortés-Hernández, P. Bartolo-Pérez, C. A. Ávila-Orta, V. J. Cruz-Delgado und A. Zepeda-Pedreguera. „Graphene Nanoplatelets Modified with Amino-Groups by Ultrasonic Radiation of Variable Frequency for Potential Adsorption of Uremic Toxins“. Nanomaterials 9, Nr. 9 (05.09.2019): 1261. http://dx.doi.org/10.3390/nano9091261.

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Chronic kidney disease (CKD) is a worldwide public health problem. In stages III and IV of CKD, uremic toxins must be removed from the patient by absorption, through a treatment commonly called hemodialysis. Aiming to improve the absorption of uremic toxins, we have studied its absorption in chemically modified graphene nanoplatelets (GNPs). This study involved the reaction between GNPs and diamines with reaction times of 30, 45 and 60 min using ultrasound waves of different amplitudes and frequencies. Functionalized GNPs were analyzed by Fourier Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy and energy dispersitive spectroscopy (SEM-EDS), and Thermogravimetric analysis (TGA). The analysis of the functional groups confirmed the presence of amide and hydroxyl groups on the surface of the GNPs by reactions of diamines with carboxylic acids and epoxides. Adsorption of uremic toxins was determined using equilibrium isotherms, where the maximum percentage of removal of uremic toxins was 97%. Dispersion of modified graphene nanoplatelets was evaluated in water, ethanol and hexane, as a result of this treatment was achieved a good and effective dispersion of diamines-modified graphene nanoplatelets in ethanol and hexane. Finally, the results of hemolysis assays of the modified graphene with amine demonstrated that it was not cytotoxic when using 500 mg/mL. The samples of modified graphene demonstrated low degree of hemolysis (<2%), so this material can be used for in vivo applications such as hemodialysis.

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McCully, K. K., S. Iotti, K. Kendrick, Z. Wang, J. D. Posner, J. Leigh und B. Chance. „Simultaneous in vivo measurements of HbO2 saturation and PCr kinetics after exercise in normal humans“. Journal of Applied Physiology 77, Nr. 1 (01.07.1994): 5–10. http://dx.doi.org/10.1152/jappl.1994.77.1.5.

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Simultaneous measurements of phosphocreatine (PCr) and oxyhemoglobin (HbO2) saturation were made during recovery from exercise in calf muscles of five male subjects. PCr was measured using magnetic resonance spectroscopy in a 2.0-T 78-cm-bore magnet with a 9-cm-diam surface coil. Relative HbO2 saturation was measured as the difference in absorption of 750- and 850-nm light with use of near-infrared spectroscopy. The light source and detectors were 3 cm apart. Exercise consisted of isokinetic plantar flexion in a supine position. Two 5-min submaximal protocols were performed with PCr depletion to 60% of resting values and with pH values of > 7.0. Then two 1-min protocols of rapid plantar flexion were performed to deplete PCr values to 5–20% of resting values with pH values of < 6.8. Areas of PCr peaks (every 8 s) and HbO2 saturation (every 1 s) were fit to a monoexponential function, and a time constant was calculated. The PCr time constant was larger after maximal exercise (68.3 +/- 10.5 s) than after submaximal exercise (36.0 +/- 6.5 s), which is consistent with the effects of low pH on PCr recovery. HbO2 resaturation approximated submaximal PCr recovery and was not different between maximal (29.4 +/- 5.5 s) and submaximal (27.6 +/- 6.0 s) exercise. We conclude that magnetic resonance spectroscopy measurements of PCr recovery and near-infrared spectroscopy measurements of recovery of HbO2 saturation provide similar information as long as muscle pH remains near 7.0.

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Wang, Chiao-Yi, Tzu-Chia Kao, Yin-Fu Chen, Wen-Wei Su, Hsin-Jou Shen und Kung-Bin Sung. „Validation of an Inverse Fitting Method of Diffuse Reflectance Spectroscopy to Quantify Multi-Layered Skin Optical Properties“. Photonics 6, Nr. 2 (30.05.2019): 61. http://dx.doi.org/10.3390/photonics6020061.

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Skin consists of epidermis and dermis layers that have distinct optical properties. The quantification of skin optical properties is commonly achieved by modeling photon propagation in tissue using Monte Carlo (MC) simulations and iteratively fitting experimentally measured diffuse reflectance spectra. In order to speed up the inverse fitting process, time-consuming MC simulations have been replaced by artificial neural networks to quickly calculate reflectance spectra given tissue geometric and optical parameters. In this study the skin was modeled to consist of three layers and different scattering properties of the layers were considered. A new inverse fitting procedure was proposed to improve the extraction of chromophore-related information in the skin, including the hemoglobin concentration, oxygen saturation and melanin absorption. The performance of the new inverse fitting procedure was evaluated on 40 sets of simulated spectra. The results showed that the fitting procedure without knowing the epidermis thickness extracted chromophore information with accuracy similar to or better than fitting with known epidermis thickness, which is advantageous for practical applications due to simpler and more cost-effective instruments. In addition, the melanin volume fraction multiplied by the thickness of the melanin-containing epidermis layer was estimated more accurately than the melanin volume fraction itself. This product has the potential to provide a quantitative indicator of melanin absorption in the skin. In-vivo cuff occlusion experiments were conducted and skin optical properties extracted from the experiments were comparable to the results of previously reported in vivo studies. The results of the current study demonstrated the applicability of the proposed method to quantify the optical properties related to major chromophores in the skin, as well as scattering coefficients of the dermis. Therefore, it has the potential to be a useful tool for quantifying skin optical properties in vivo.

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West, D. P., N. Alperin, M. D. Yang, G. Micali, B. Cook und R. L. Koch. „In vivo flurbiprofen skin absorption assessed by magnetic resonance spectroscopy and measurement of plasma concentration via HPLC.“ Clinical Pharmacology & Therapeutics 59, Nr. 2 (Februar 1996): 167. http://dx.doi.org/10.1038/sj.clpt.1996.169.

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Cogdell, Richard J., Andrew Gall und Jürgen Köhler. „The architecture and function of the light-harvesting apparatus of purple bacteria: from single molecules to in vivo membranes“. Quarterly Reviews of Biophysics 39, Nr. 3 (August 2006): 227–324. http://dx.doi.org/10.1017/s0033583506004434.

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1. Introduction 2292. Structures 2342.1 The structure of LH2 2342.2 Natural variants of peripheral antenna complexes 2422.3 RC–LH1 complexes 2423. Spectroscopy 2493.1 Steady-state spectroscopy 2493.2 Factors which affect the position of the Qy absorption band of Bchla 2494. Regulation of biosynthesis and assembly 2574.1 Regulation 2574.1.1 Oxygen 2574.1.2 Light 2584.1.2.1 AppA: blue-light-mediated regulation 2594.1.2.2 Bacteriophytochromes 2594.1.3 From the RC to the mature PSU 2614.2 Assembly 2614.2.1 LH1 2624.2.2 LH2 2635. Frenkel excitons 2655.1 General 2655.2 B800 2675.3 B850 2675.4 B850 delocalization 2736. Energy-transfer pathways: experimental results 2746.1 Theoretical background 2746.2 ‘Follow the excitation energy’ 2766.2.1 Bchla→Bchla energy transfer 2776.2.1.1 B800→B800 2776.2.1.2 B800→B850 2786.2.1.3 B850→B850 2796.2.1.4 B850→B875 2806.2.1.5 B875→RC 2806.2.2 Car[harr ]Bchla energy transfer 2817. Single-molecule spectroscopy 2847.1 Introduction to single-molecule spectroscopy 2847.2 Single-molecule spectroscopy on LH2 2857.2.1 Overview 2857.2.2 B800 2867.2.2.1 General 2867.2.2.2 Intra- and intercomplex disorder of site energies 2877.2.2.3 Electron-phonon coupling 2897.2.2.4 B800→B800 energy transfer revisited 2907.2.3 B850 2938. Quantum mechanics and the purple bacteria LH system 2989. Appendix 2999.1 A crash course on quantum mechanics 2999.2 Interacting dimers 30510. Acknowledgements 30611. References 307This review describes the structures of the two major integral membrane pigment complexes, the RC–LH1 ‘core’ and LH2 complexes, which together make up the light-harvesting system present in typical purple photosynthetic bacteria. The antenna complexes serve to absorb incident solar radiation and to transfer it to the reaction centres, where it is used to ‘power’ the photosynthetic redox reaction and ultimately leads to the synthesis of ATP. Our current understanding of the biosynthesis and assembly of the LH and RC complexes is described, with special emphasis on the roles of the newly described bacteriophytochromes. Using both the structural information and that obtained from a wide variety of biophysical techniques, the details of each of the different energy-transfer reactions that occur, between the absorption of a photon and the charge separation in the RC, are described. Special emphasis is given to show how the use of single-molecule spectroscopy has provided a more detailed understanding of the molecular mechanisms involved in the energy-transfer processes. We have tried, with the help of an Appendix, to make the details of the quantum mechanics that are required to appreciate these molecular mechanisms, accessible to mathematically illiterate biologists. The elegance of the purple bacterial light-harvesting system lies in the way in which it has cleverly exploited quantum mechanics.

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Samuel, P., B. Pavithra, R. Priyadarshini, V. Maheswari, J. Vijayakumar und T. Selvarathinam. „TOXICITY STUDIES ON SILVER AND COPPER NANOPARTICLES“. INDIAN DRUGS 55, Nr. 09 (28.09.2018): 58–60. http://dx.doi.org/10.53879/id.55.09.11399.

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In a pilot scale study, silver and copper nanoparticles were synthesized from two different plant sources viz Flacourtia indica and Prosopsis juliflora. The in vivo toxicity of silver and copper nanoparticles was tested on Danio rerio (Zebra fish) under different concentrations (1 ppm, 10 ppm and 100 ppm). Through the investigation, the nanoparticles treated fishes developed with hyper pigmentation in the ventral region. The minimum lethal concentration required to bring lethality caused by silver nanoparticle was 10 ppm whereas for copper nanoparticles it was 1 ppm. Further, the concentration of silver and copper nanoparticles accumulated inside the fish was evaluated by Atomic Absorption Spectroscopy. The in vivo concentration of silver and copper nanoparticles steadily increases with increase in dosage of nanoparticles being tested.

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Navolokin, Nikita, Sergei German, Alla Bucharskaya, Olga Godage, Viktor Zuev, Galina Maslyakova, Nikolaiy Pyataev et al. „Systemic Administration of Polyelectrolyte Microcapsules: Where Do They Accumulate and When? In Vivo and Ex Vivo Study“. Nanomaterials 8, Nr. 10 (10.10.2018): 812. http://dx.doi.org/10.3390/nano8100812.

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Multilayer capsules of 4 microns in size made of biodegradable polymers and iron oxide magnetite nanoparticles have been injected intravenously into rats. The time-dependent microcapsule distribution in organs was investigated in vivo by magnetic resonance imaging (MRI) and ex vivo by histological examination (HE), atomic absorption spectroscopy (AAS) and electron spin resonance (ESR), as these methods provide information at different stages of microcapsule degradation. The following organs were collected: Kidney, liver, lung, and spleen through 15 min, 1 h, 4 h, 24 h, 14 days, and 30 days after intravenous injections (IVIs) of microcapsules in a saline buffer at a dosage of 2.5 × 109 capsule per kg. The IVI of microcapsules resulted in reversible morphological changes in most of the examined inner organs (kidney, heart, liver, and spleen). The capsules lost their integrity due to degradation over 24 h, and some traces of iron oxide nanoparticles were seen at 7 days in spleen and liver structure. The morphological structure of the tissues was completely restored one month after IVI of microcapsules. Comprehensive analysis of the biodistribution and degradation of entire capsules and magnetite nanoparticles as their components gave us grounds to recommend these composite microcapsules as useful and safe tools for drug delivery applications.

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Xu, Chunying, Gang Li, Liju Gan und Baiqing Yuan. „In Situ Electrochemical Formation of Oxo-Functionalized Graphene on Glassy Carbon Electrode with Chemical Fouling Recovery and Antibiofouling Properties for Electrochemical Sensing of Reduced Glutathione“. Antioxidants 12, Nr. 1 (21.12.2022): 8. http://dx.doi.org/10.3390/antiox12010008.

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Electrochemical detection can be used to achieve intracellular or in vivo analysis of reduced glutathione (GSH) in tissues such as brain by using a microelectrode, which can help to better understand the complex biochemical processes of this molecule in the human body. The main challenges associated with electrochemical GSH detection are the chemical fouling of electrodes, caused by the oxidation product of GSSG, and biofouling due to the non-specific absorption of biological macromolecules. Oxo-functionalized graphene was generated in situ on the surface of a glassy carbon electrode using a green electrochemical method without using any other modifiers or materials in a mild water solution. The fabricated oxo-functionalized graphene interface was characterized by Raman spectroscopy, X-ray photoelectron spectroscopy, electrochemistry, electrochemical impedance spectroscopy, and contact angle measurements. The interface showed high electrocatalytic activity towards the oxidation of GSH, and a simple and efficient GSH sensor was developed. Interestingly, the electrode is reusable and could be recovered from the chemical fouling via electrochemical oxidation and reduction treatment. The electrode also exhibited good antibiofouling properties. The presented method could be a promising method used to treat carbon materials, especially carbon-based microelectrodes for electrochemical monitoring of intracellular glutathione or in vivo analysis.

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Solouma, Nahed, und Omnia Hamdy. „Ex Vivo Optical Properties Estimation for Reliable Tissue Characterization“. Photonics 10, Nr. 8 (01.08.2023): 891. http://dx.doi.org/10.3390/photonics10080891.

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: Lasers are demonstrating high impact in many medical and biological applications. They have different interaction mechanisms within tissues depending on operational parameters, particularly the wavelength. In addition, the optical properties of the examined tissue (i.e., absorption and scattering properties) influence the efficacy of the applied laser. The development of optical biomedical techniques relies on the examination of tissues’ optical properties, which describe the viability of tissue optical evaluation and the effect of light on the tissue. Understanding the optical properties of tissues is necessary for the interpretation and evaluation of diagnostic data, as well as the prediction of light and energy absorption for therapeutic and surgical applications. Moreover, the accuracy of many applications, including tissue removal and coagulation, depends on the tissues' spectroscopic characteristics. In the current paper, a set of ex vivo absorption and scattering coefficients of different types of biological samples (skin, skull, liver and muscle) at 650 nm laser irradiation were retrieved using an integrating phere system paired with the Kubelka–Munk model. The obtained optical parameters were utilized to acquire the local fluence rate within the irradiated tissues based on the Monte Carlo simulation method and the diffusion approximation of the radiative transfer equation. The obtained results reveal that the optical absorption and scattering coefficients control the light propagation and distribution within biological tissues. Such an understanding refers to system design optimization, light delivery accuracy and the minimization of undesirable physiological effects such as phototoxicity or photobleaching.

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LI, ZHIQIU, SHUDONG JIANG, VENKATARAMANAN KRISHNASWAMY, SCOTT C. DAVIS, SUBHADRA SRINIVASAN, KEITH D. PAULSEN und BRIAN W. POGUE. „MR-GUIDED PULSE OXIMETRY IMAGING OF BREAST IN VIVO“. Journal of Innovative Optical Health Sciences 04, Nr. 02 (April 2011): 199–208. http://dx.doi.org/10.1142/s1793545811001459.

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A near-infrared (NIR) tomography system with spectrally-encoded sources in two wavelength bands was built to quantify the temporal oxyhemoglobin and deoxyhemoglobin contrast in breast tissue at a 20 Hz bandwidth. The system was integrated into a 3 T magnetic resonance (MR) imaging system through a customized breast coil interface for simultaneous optical and MRI acquisition. In this configuration, the MR images provide breast tissue structural information for NIR spectroscopy of adipose and fibro-glandular tissue in breast. Spectral characterization performance of the NIR system was verified through dynamic phantom experiments. Normal human subjects were imaged with finger pulse oximeter (PO) plethysmogram synchronized to the NIR system to provide a frequency-locked reference. Both the raw data from the NIR system and the recovered absorption coefficients of the breast at two wavelengths showed the same frequency of about 1.3 Hz as the PO output. The frequency lock-in approach provided a practical platform for MR-localized recovery of small pulsatile variations of oxyhemoglobin and deoxyhemoglobin in the breast, which are related to the heartbeat and vascular resistance of the tissue.

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Casiano-Muñiz, Ileska M., Melissa I. Ortiz-Román, Génesis Lorenzana-Vázquez und Félix R. Román-Velázquez. „Synthesis, Characterization, and Ecotoxicology Assessment of Zinc Oxide Nanoparticles by In Vivo Models“. Nanomaterials 14, Nr. 3 (24.01.2024): 255. http://dx.doi.org/10.3390/nano14030255.

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The widespread use of zinc oxide nanoparticles (ZnO NPs) in multiple applications has increased the importance of safety considerations. ZnO NPs were synthesized, characterized, and evaluated for toxicity in Artemia salina and zebrafish (Danio rerio). NPs were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and ultraviolet-visible (UV-Vis) spectroscopy. The hydrodynamic size and stability of the ZnO NP surface were examined using a Zetasizer. Characterization techniques confirmed the ZnO wurtzite structure with a particle size of 32.2 ± 5.2 nm. Synthesized ZnO NPs were evaluated for acute toxicity in Artemia salina using the Probit and Reed and Muench methods to assess for lethal concentration at 50% (LC50). The LC50 was 86.95 ± 0.21 μg/mL in Artemia salina. Physical malformations were observed after 96 h at 50 μg/mL of exposure. The total protein and cytochrome P450 contents were determined. Further analysis was performed to assess the bioaccumulation capacity of zebrafish (Danio rerio) using ICP-OES. ZnO NP content in adult zebrafish was greater in the gastrointestinal tract than in the other tissues under study. The present analysis of ZnO NPs supports the use of Artemia salina and adult zebrafish as relevant models for assessing toxicity and bioaccumulation while considering absorption quantities.

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Eloy, Josimar Oliveira, Juliana Saraiva, Sérgio de Albuquerque und Juliana Maldonado Marchetti. „Preparation, characterization and evaluation of the in vivo trypanocidal activity of ursolic acid-loaded solid dispersion with poloxamer 407 and sodium caprate“. Brazilian Journal of Pharmaceutical Sciences 51, Nr. 1 (März 2015): 101–9. http://dx.doi.org/10.1590/s1984-82502015000100011.

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Ursolic acid is a promising candidate for treatment of Chagas disease; however it has low aqueous solubility and intestinal absorption, which are both limiting factors for bioavailability. Among the strategies to enhance the solubility and dissolution of lipophilic drugs, solid dispersions are growing in popularity. In this study, we employed a mixture of the surfactants poloxamer 407 with sodium caprate to produce a solid dispersion containing ursolic acid aimed at enhancing both drug dissolution and in vivo trypanocidal activity. Compared to the physical mixture, the solid dispersion presented higher bulk density and smaller particle size. Fourier Transform Infrared Spectroscopy results showed hydrogen bonding intermolecular interactions between drug and poloxamer 407. X-ray diffractometry experiments revealed the conversion of the drug from its crystalline form to a more soluble amorphous structure. Consequently, the solubility of ursolic acid in the solid dispersion was increased and the drug dissolved in a fast and complete manner. Taken together with the oral absorption-enhancing property of sodium caprate, these results explained the increase of the in vivo trypanocidal activity of ursolic acid in solid dispersion, which also proved to be safe by cytotoxicity evaluation using the LLC-MK2 cell line.

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Xi, Ziyue, Wei Zhang, Yali Fei, Mingshu Cui, Luyao Xie, Lu Chen und Lu Xu. „Evaluation of the Solid Dispersion System Engineered from Mesoporous Silica and Polymers for the Poorly Water Soluble Drug Indomethacin: In Vitro and In Vivo“. Pharmaceutics 12, Nr. 2 (10.02.2020): 144. http://dx.doi.org/10.3390/pharmaceutics12020144.

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This work explored absorption efficacy via an in vivo imaging system and parallel artificial membrane penetration in indomethacin (IMC) solid dispersion (SD) systems. Two different polymer excipients—hydroxypropyl methylcellulose (HPMC) and Kollicoat IR as precipitation inhibitors (PIs)—combined with mesoporous silica nanoparticles (MSNs) as carriers were investigated. The IMC–SDs were prepared using the solvent evaporation method and characterized by solubility analysis, infrared (IR) spectroscopy, powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FESEM), and differential scanning calorimetry (DSC). It was confirmed that IMC successfully changed into an amorphous state after loading into the designed carriers. The in vitro release and stability experiments were conducted to examine the in vitro dissolution rates of IMC–SDs combined with HPMC and Kollicoat IR as PIs which both improved approximately three-fold to that of the pure drug. Finally, in vivo studies and in vitro parallel artificial membrane penetration (PAMPA) experiments ensured the greater ability of enhancing the dissolution rates of pure IMC in the gastrointestinal tract by oral delivery. In brief, this study highlights the prominent role of HPMC and Kollicoat IR as PIs in MSN SD systems in improving the bioavailability and gastrointestinal oral absorption efficiency of indomethacin.

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Haidl, H., K. Knödlmayr, W. Rüdiger, H. Scheer, S. Schoch und J. Ullrich. „Degradation of Bacteriochlorophyll a in Rhodopseudomonas sphaeroides R26“. Zeitschrift für Naturforschung C 40, Nr. 9-10 (01.08.1985): 685–92. http://dx.doi.org/10.1515/znc-1985-9-1018.

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Abstract A series of pigments of the bacteriopheophytin a spectral type have been isolated from ageing cultures of Rhodopseudomonas sphaeroides strain R26. These pigments are formed in varying amounts, and can be most readily analyzed in vivo by their absorption in the 530 nm spectral range. They are enriched in sedimenting cells, but their formation is not affected by light. By chromatographic comparison with authentic pigments and chemical correlation, the following pigments have been identified: bacteriopheophytin a, bacteriopheophorbide a (which is the predominant product), pyrobacteriopheophorbide a and a fourth, very polar bacteriopheophytin a-type product of unknown structure. The major portion of these newly formed pigments is present in the cells in a state, in which the near-infrared absorption band is shifted to longer wavelengths. As shown by low temperature fluorescence spectroscopy, these forms are very similar to bacteriopheophorbide a aggregates.

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Cerussi, Albert, Natasha Shah, David Hsiang, Amanda Durkin, John Butler und Bruce J. Tromberg. „In vivo absorption, scattering, and physiologic properties of 58 malignant breast tumors determined by broadband diffuse optical spectroscopy“. Journal of Biomedical Optics 11, Nr. 4 (2006): 044005. http://dx.doi.org/10.1117/1.2337546.

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Gomes, Marcos H. F., Bianca A. Machado, Eduardo S. Rodrigues, Gabriel Sgarbiero Montanha, Mônica Lanzoni Rossi, Rafael Otto, Francisco S. Linhares und Hudson W. P. Carvalho. „In Vivo Evaluation of Zn Foliar Uptake and Transport in Soybean Using X-ray Absorption and Fluorescence Spectroscopy“. Journal of Agricultural and Food Chemistry 67, Nr. 44 (14.10.2019): 12172–81. http://dx.doi.org/10.1021/acs.jafc.9b04977.

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Jackowski, Grzegorz, und Stefan Jansson. „Characterization of Photosystem II Antenna Complexes Separated by Non-Denaturing Isoelectric Focusing“. Zeitschrift für Naturforschung C 53, Nr. 9-10 (01.10.1998): 841–48. http://dx.doi.org/10.1515/znc-1998-9-1010.

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CP26, CP29 and three different LHC II subcomplexes have been purified from a carnation photosystem II (PSII) preparation using non-denaturing isoelectric focusing in a vertical polyacrylamide slab gel. The identity of the fractions was established by absorption spectroscopy, SDS-PAGE and immunoblotting. CP26 comprised a single apoprotein of 26.6 kDa and CP29 contained two apoproteins of 28.8 and 28.5 kDa. LHC II subcomplex A consisted of Lhcb1 homotrimers, and subcomplexes B and C consisted of Lhcb1/Lhcb2 and Lhcb1/Lhcb3 heterotrimers, respectively. We discuss the data in relation to the organization of the PS II antenna in vivo.

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