The concentration difference of major elements in melanocytic skin with respect to pigmentation level is analysed by laser‐induced breakdown spectroscopy (LIBS) to investigate the applicability of LIBS as an in situ feedback tool for selective and complete laser removal of melanocytic skin tissue like nevus. The skin of black silkie chicken which had a characteristic darkly pigmented perifollicular skin surrounded by lightly pigmented extrafollicular skin was used as the sample. The results showed higher LIBS signal intensities of Ca2+ and Mg2+ but lower intensities of Na+, Cl– and K+ in the perifollicular skin than in the extrafollicular skin, which demonstrated the feasibility to use LIBS as a reliable method to distinguish skin tissues with difference in pigmentation level.
Plasma emission of biochemical elements generated with a laser irradiation on melanocytic skin lesion. 相似文献
Screening of proteins for crystallization under laser irradiation was investigated using six proteins: ribonuclease B, glucose dehydrogenase, lysozyme, sorbitol dehydrogenase, fructose dehydrogenase and myoglobin. Shining 532 nm green circularly polarized laser light with a picosecond pulse and 6 mW power for 30 s on newly set‐up protein drops showed a marked improvement in the number of screen conditions amenable for crystal growth compared with control drops under identical conditions but without laser exposure. For glucose dehydrogenase and sorbitol dehydrogenase, larger and better quality crystals were formed and the resolution of X‐ray diffraction was improved. The speed of crystallization increased in the case of ribonuclease B, lysozyme and sorbitol dehydrogenase. During laser irradiation, the amount of precipitation in the screened drops increased, indicating a transient decrease in protein solubility. At the optimized laser settings, there was no deleterious effect of the laser on crystal growth or on the protein. In the cases of ribonuclease B and lysozyme the crystal packing did not change owing to the laser exposure. 相似文献
Calcific aortic valve disease (CAVD) is a major cardiovascular disorder caused by osteogenic differentiation of valvular interstitial cells (VICs) within aortic valves. Conventional methods like colorimetric assays and histology fail to detect small calcium depositions during in‐vitro VIC cultures. Laser‐induced breakdown spectroscopy (LIBS) is a robust analytical tool used for inorganic materials characterizations, but relatively new to biomedical applications. We employ LIBS, for the first time, for quantitative in‐vitro detection of calcium depositions in VICs at various osteogenic differentiation stages. VICs isolated from porcine aortic valves were cultured in osteogenic media over various days. Colorimetric calcium assays based on arsenazo dye and Von Kossa staining measured the calcium depositions within VICs. Simultaneously, LIBS signatures for Ca I (422.67 nm) atomic emission lines were collected for estimating calcium depositions in lyophilized VIC samples. Our results indicate excellent linear correlation between the calcium assay and our LIBS measurements. Furthermore, unlike the assay results, the LIBS results could resolve calcium signals from cell samples with as early as 2 days of osteogenic culture. Quantitatively, the LIBS measurements establish the limit of detection for calcium content in VICs to be ～0.17±0.04 μg which indicates a 5‐fold improvement over calcium assay. Picture : Quantitative LIBS enables in‐vitro analysis for early stage detection of calcium deposition within aortic valvular interstitial cells (VICs).
Quantitative laser‐induced breakdown spectroscopy (LIBS) is successfully used for in‐vitro analysis of early stage calcification in aortic valvular interstitial cells (VICs). LIBS results indicate 5‐fold improvement in the detection limit of calcium deposition in VICs over cell histology techniques involving staining and colorimetric calcium assays. These results can establish LIBS at the forefront of early detection of calcification in VICs for pathological studies on Calcific Aortic Valve Disease (CAVD). Further details can be found in the article by Seyyed Ali Davari et al. ( e201600288 ).
Plasmon‐enhanced gold nanorod (AuNR) with high photothermal conversion efficiency is a promising light‐controllable nanodrug delivery system for cancer therapy. Understanding the mechanism for the light‐controllable drug release of AuNR delivery systems is important for the development of nanomedicine. In this study, the rhodamine B (RB) released from AuNR‐RB nanodelivery system was quantitated and visualized by using two‐photon luminescence (TPL) imaging combined with correlation spectroscopy. The photofragmentation of AuNR induced by femtosecond pulsed laser was revealed by TPL correlation spectroscopy when the laser energy was above the thermal damage threshold of AuNR, and the RB released from this nanodrug delivery system was visualized by TPL imaging. Furthermore, the photofragmentation‐induced release of RB from AuNR‐RB nanodelivery system was visualized in living MCF‐7 breast cancer cells by TPL imaging combined with correlation spectroscopy. These results provided a novel optical approach to quantify the release of drugs from gold nanocarriers in complex biological media. 相似文献
Objective: To see whether a fat‐rich (50%) evening meal promoted fat oxidation and a different spontaneous food intake on the following day at breakfast than a meal with a lower fat content (20%) in 10 prepubertal obese girls. Research Methods and Procedures: The postabsorptive and postprandial (10.5 hours) energy expenditure after a low‐fat (LF) (20% fat, 68% carbohydrate, 12% protein) and an isocaloric (2.1 MJ) and isoproteic high‐fat (HF; 50% fat, 38% carbohydrate, 12% protein) meal were measured by in direct calorimetry. Results: Fat oxidation was not significantly different after the two meals [LF, 31 ± 9 vs. HF, 35 ± 9 g/10.5 hours, p = not significant (NS)]. The girls oxidized 1.8 ± 0.9 times more fat than that ingested (11.1 grams) with the LF meal vs. 0.3 ± 0.3 times more fat than that ingested (27.1 grams) with the HF meal (p < 0.001). Carbohydrate oxidation was significantly higher after an LF than an HF meal (39 ± 12 vs. 29 ± 9 g/10.5 hours, p < 0, 05). At breakfast, the girls spontaneously ingested a similar amount of energy (1.5 ± 0.7 vs. 1.5 ± 0.6 MJ, p = NS) and macronutrient proportions (fat, 23% vs. 26%, p = NS; protein, 9% vs. 10%; carbohydrate, 68% vs. 64%,) independently of their having eaten an HF or an LF dinner. Discussion: An HF dinner did not stimulate fat oxidation, and no compensatory effect in spontaneous food intake was observed during breakfast the following morning. Cumulated total fat oxidation after dinner was higher than total fat ingested at dinner, but a much larger negative fat balance was observed after the LF meal. Spontaneous energy and nutrient intakes at breakfast were similar after LF and HF isocaloric, isoproteic dinners. This study points out the lack of sensitivity of short‐term fat balance to subsequently readjust fat intake and emphasizes the importance of an LF meal to avoid transient positive fat imbalance. 相似文献
Cold atmospheric‐pressure plasmas have become of increasing importance in sterilization processes especially with the growing prevalence of multi‐resistant bacteria. Albeit the potential for technological application is obvious, much less is known about the molecular mechanisms underlying bacterial inactivation. X‐jet technology separates plasma‐generated reactive particles and photons, thus allowing the investigation of their individual and joint effects on DNA. Raman spectroscopy shows that particles and photons cause different modifications in DNA single and double strands. The treatment with the combination of particles and photons does not only result in cumulative, but in synergistic effects. Profilometry confirms that etching is a minor contributor to the observed DNA damage in vitro.
Schematics of DNA oligomer treatment with cold atmospheric‐pressure plasma. 相似文献
Ultrashort pulse lasers offer great promise for tissue resection with exceptional precision and minimal thermal damage. Surgery in the bowel requires high precision and minimal necrotic tissue to avoid severe complications such as perforation. The deployment of ultrashort lasers in minimally invasive or endoscopic procedures has been hindered by the lack of suitable optical fibres for high peak powers. However, recent developments of hollow core microstructured fibres provide potential for delivery of such pulses throughout the body. In this study, analysis of laser ablation via a scanning galvanometer on a porcine colon tissue model is presented. A thermally damaged region (<85 μm) and fine depth control of ablation using the pulse energies 46 and 33 μJ are demonstrated. It is further demonstrated that such pulses suitable for precision porcine colon resection can be flexibly delivered via a hollow core negative curvature fibre (HC‐NCF) and again ablation depth can be controlled with a thermally damaged region <85 μm. Ablation volumes are comparable to that of early stage lesions in the inner lining of the colon. This study concludes that the combination of ultrashort pulses and flexible fibre delivery via HC‐NCF present a viable route to new minimally invasive surgical procedures. 相似文献
Plants are one of the most important parts of the ecological system and demand a reliable method for accurate classification. In this study, the first‐derivative fluorescence spectral curves (FDFSCs) based on laser‐induced fluorescence technology were proposed for the characterization of plant species. The measurement system is mainly composed of a spectrometer, an excitation light source (the two excitation wavelengths are 460 and 556 nm, respectively), and an intensified charge‐coupled device camera. FDFSCs were calculated from the deviation between the fluorescence values at each wavelength, plus and minus one band, divided by the wavelength range. Principal component analysis was utilized to analyze the FDFSCs by extracting the main attributes and reducing the dimensionality of variables. A support vector machine was used to evaluate FDFSC performance for the identification of plant species. Plant species that are difficult to distinguished by the naked eye, can be identified effectively using the proposed FDFSCs. For the 556 nm and 460 nm excitation wavelengths, the overall identification rates of the six plant species evaluated were 93.3% and 91.7%, respectively. Experimental results demonstrated that the combination of the FDFSCs with multivariate analysis could provide a simple and reliable method for the characterization of plant species. 相似文献
Fasting promotes triglyceride (TG) accumulation in lean tissues of some animals, but the effect in humans is unknown. Additionally, fasting lipolysis is sexually dimorphic in humans, suggesting that lean tissue TG accumulation and metabolism may differ between women and men. This study investigated lean tissue TG content and metabolism in women and men during extended fasting. Liver and muscle TG content were measured by magnetic resonance spectroscopy during a 48-h fast in healthy men and women. Whole-body and hepatic carbohydrate, lipid, and energy metabolism were also evaluated using biochemical, calorimetric, and stable isotope tracer techniques. As expected, postabsorptive plasma fatty acids (FAs) were higher in women than in men but increased more rapidly in men with the onset of early starvation. Concurrently, sexual dimorphism was apparent in lean tissue TG accumulation during the fast, occurring in livers of men but in muscles of women. Despite differences in lean tissue TG distribution, men and women had identical fasting responses in whole-body and hepatic glucose and oxidative metabolism. In conclusion, TG accumulated in livers of men but in muscles of women during extended fasting. This sexual dimorphism was related to differential fasting plasma FA concentrations but not to whole body or hepatic utilization of this substrate. 相似文献
Small animal deep‐tissue fluorescence imaging in the second Biological Window (II‐BW, 1000–1350 nm) is limited by the presence of undesirable infrared‐excited, infrared‐emitted (900–1700 nm) autofluorescence whose origin, spectral properties and dependence on strains is still unknown. In this work, the infrared autofluorescence and laser‐induced whole body heating of five different mouse strains with distinct coat colors (black, grey, agouti, white and nude) has been systematically investigated. While neither the spectral properties nor the magnitude of organ autofluorescence vary significantly between mouse strains, the coat color has been found to strongly determine both the autofluorescence intensity as well as the laser‐induced whole body heating. Results included in this work reveal mouse strain as a critical parameter that has to be seriously considered in the design and performance of small animal imaging experiments based on infrared‐emitting fluorescent markers.
Objective: Childhood obesity is an emerging health problem. This study assesses the effects of three levels of dietary fat (10%, 32%, and 45% measured by kilocalories) on weight gain, body composition, energy metabolism, and comorbidity factors in rats from weaning through maturation. Research Methods and Procedures: The role of dietary fat on the susceptibility to obesity was assessed by feeding diets containing three levels of dietary fat to rats from weaning through 7 months of age. Body composition was analyzed by DXA after 6 and 12 weeks of dietary treatment. Energy metabolism was measured by indirect calorimetry. Results: Energy intake, weight gain, fat mass, and plasma glucose, cholesterol, triglyceride, free fatty acid, leptin, and insulin levels increased dose‐dependently with increased dietary fat. No difference in absolute lean mass among the three groups was observed. Therefore, the differences in weight gain are accounted for primarily by increased fat accretion. Compared with rats that were relatively resistant to obesity when on a 45% fat diet, diet‐induced obesity‐prone rats were in positive energy balance and had an elevated respiratory quotient, indicating a switch in energy substrate use from fat to carbohydrate, which promotes body‐fat accretion. Discussion: Our data support the hypothesis that administration of increasing amount of dietary fat to very young rats enhances susceptibility to diet‐induced obesity and its comorbidities. 相似文献
The tensile strength of the intervertebral disc (IVD) is mainly maintained by collagen cross‐links. Loss of collagen cross‐linking combined with other age‐related degenerative processes contributes to tissue weakening, biomechanical failure, disc herniation and pain. Exogenous collagen cross‐linking has been identified as an effective therapeutic approach for restoring IVD tensile strength. The current state‐of‐the‐art method to assess the extent of collagen cross‐linking in tissues requires destructive procedures and high‐performance liquid chromatography. In this study, we investigated the utility of infrared attenuated total reflection (IR‐ATR) spectroscopy as a nondestructive analytical strategy to rapidly evaluate the extent of UV‐light‐activated riboflavin (B2)‐induced collagen cross‐linking in bovine IVD samples. Thirty‐five fresh bovine‐tail IVD samples were equally divided into five treatment groups: (a) untreated, (b) cell culture medium Dulbecco's Modified Eagle's Medium only, (c) B2 only, (d) UV‐light only and (e) UV‐light‐B2. A total of 674 measurements have been acquired, and were analyzed via partial least squares discriminant analysis. This classification scheme unambiguously identified individual classes with a sensitivity >91% and specificity >92%. The obtained results demonstrate that IR‐ATR spectroscopy reliably differentiates between different treatment categories, and promises an excellent tool for potential in vivo, nondestructive and real‐time assessment of exogenous IVD cross‐linking. 相似文献
Objective: To investigate whether there is a difference in sensitivity to a serotonin agonist, meta‐chlorophenylpiperazine (mCPP), or cholecystokinin (CCK‐8), an intestinal hormone that inhibits food intake, between the Osborne‐Mendel (OM) rat, which becomes obese eating a high‐fat diet, and the S5B/Pl (S5B) rat, which is resistant to dietary‐induced obesity. Research Methods and Procedures: OM and S5B rats were adapted to either a high‐saturated‐fat diet (56% energy as fat) or a low‐fat diet (10% energy as fat) or to both for 14 days and then treated with several doses of mCPP or CCK‐8. Results: Treatment with mCPP reduced food intake in both strains of rats. The dose‐response curve showed that the OM rats had an increased sensitivity to the serotonergic agonist. Animals eating the high‐fat diet had less response to mCPP; and in the S5B rats, the response was significantly reduced. After treatment with CCK‐8, there was a similar dose‐related suppression of food intake in both the OM and S5B rats. Discussion: These data are consistent with the hypothesis that the serotonin system in the S5B rat has a greater activity that could act to inhibit fat intake. The response to CCK was not significantly affected by strain or diet. 相似文献
Nowadays, multiphase flows occur in many different applications in everyday life or industrial context. Consequently, the understanding of transport phenomenolgy between the participating phases is a crucial task of recent and prospective research. When it comes to the optimization of absorption and chemical reaction tasks in process industry, in‐depth knowledge concerning mass transfer is required. The laser‐induced fluorescence (LIF) imaging is therefore a promising optical measurement technique to characterize concentration fields with high spatial and temporal resolution. This review gives an overview of the different fields of research within which LIF measurements are carried out, with focus on gas‐liquid systems. Chances and obstacles of recently publicated results as well as experiences of LIF methods regarding multiphase flows are presented and discussed. 相似文献
