scholarly journals Effect of Localized Mechanical Indentation on Skin Water Content Evaluated Using OCT

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Abhijit A. Gurjarpadhye ◽  
William C. Vogt ◽  
Yajing Liu ◽  
Christopher G. Rylander
Keyword(s):  
Refractive Index ◽  
Signal Intensity ◽  
Volume Fraction ◽  
Ex Vivo ◽  
Incident Light ◽  
Effective Strain ◽  
Water Volume ◽  
Porcine Skin ◽  
Swept Source

The highly disordered refractive index distribution in skin causes multiple scattering of incident light and limits optical imaging and therapeutic depth. We hypothesize that localized mechanical compression reduces scattering by expulsing unbound water from the dermal collagen matrix, increasing protein concentration and decreasing the number of index mismatch interfaces between tissue constituents. A swept-source optical coherence tomography (OCT) system was used to assess changes in thickness and group refractive index inex vivoporcine skin, as well as changes in signal intensity profile when imagingin vivohuman skin. Compression ofex vivoporcine skin resulted in an effective strain of −58.5%, an increase in refractive index from 1.39 to 1.50, and a decrease in water volume fraction from 0.66 to 0.20.In vivoOCT signal intensity increased by 1.5 dB at a depth of 1 mm, possibly due to transport of water away from the compressed regions. These finding suggest that local compression could be used to enhance light-based diagnostic and therapeutic techniques.

scholarly journals Quantitative Swept-Source Optical Coherence Tomography of Early Enamel Erosion in vivo

2017 ◽  
Vol 51 (4) ◽  
pp. 410-418 ◽  
Author(s):  
Rupert S. Austin ◽  
Maisalamah Haji Taha ◽  
Frederic Festy ◽  
Richard Cook ◽  
Manoharan Andiappan ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Healthy Volunteers ◽  
Orange Juice ◽  
Signal Intensity ◽  
Surface States ◽  
Enamel Surface ◽  
Optical Coherence ◽  
Swept Source ◽  
Water Rinsing

Swept-source optical coherence tomography (SS-OCT) shows potential for the in vivo quantitative evaluation of micro-structural enamel surface phenomena occurring during early erosive demineralization. This randomized controlled single-blind cross-over clinical study aimed to evaluate the use of SS-OCT for detecting optical changes in the enamel of 30 healthy volunteers subjected to orange juice rinsing (erosive challenge) in comparison to mineral water rinsing (control), according to wiped and non-wiped enamel surface states. Participants were randomly allocated to 60 min of orange juice rinsing (pH 3.8) followed by 60 min of water rinsing (pH 6.7) and vice versa, with a 2-week wash-out period. In addition, the labial surfaces of the right or left maxillary incisors were wiped prior to SS-OCT imaging. An automated ImageJ algorithm was designed to analyse the back-scattered OCT signal intensity (D) after orange juice rinsing compared to after water rinsing. D was quantified as the OCT signal scattering from the 33 µm sub-surface enamel, normalised by the total OCT signal intensity entering the enamel. The back-scattered OCT signal intensity increased by 3.1% (95% CI 1.1-5.1%) in the wiped incisors and by 3.5% (95% CI 1.5-5.5%) in the unwiped incisors (p < 0.0001). Wiping reduced the back-scattered OCT signal intensity by 1.7% (95% CI -3.2 to -0.3%; p = 0.02) in comparison to the unwiped enamel surfaces for both rinsing solutions (p = 0.2). SS-OCT detected OCT signal changes in the superficial sub-surface enamel of maxillary central incisor teeth of healthy volunteers after orange juice rinsing.

Fiber-needle Swept-source Optical Coherence Tomography System for the Identification of the Epidural Space in Piglets

2015 ◽  
Vol 122 (3) ◽  
pp. 585-594 ◽  
Author(s):  
Wen-Chuan Kuo ◽  
Meng-Chun Kao ◽  
Kuang-Yi Chang ◽  
Wei-Nung Teng ◽  
Mei-Yung Tsou ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Epidural Space ◽  
Ex Vivo ◽  
Optical Probe ◽  
Epidural Needle ◽  
Optical Coherence ◽  
Fiber Probe ◽  
Swept Source ◽  
Signal Intensities

Abstract Background: Epidural needle insertion is traditionally a blind technique whose success depends on the experience of the operator. The authors describe a novel method using a fiber-needle–based swept-source optical coherence tomography (SSOCT) to identify epidural space. Methods: An optical fiber probe was placed into a hollow 18-gauge Tuohy needle. It was then inserted by an experienced anesthesiologist to continuously construct a series of two-dimensional SSOCT images by mechanically rotating the optical probe. To quantify this observation, both the average SSOCT signal intensities and their diagnostic potentials were assessed. The insertions were performed three times into both the lumbar and thoracic regions of five pigs using a paramedian approach. Results: A side-looking SSOCT is constructed to create a visual image of the underlying structures. The image criteria for the identification of the epidural space from the outside region were generated by the analysis of a training set (n = 100) of ex vivo data. The SSOCT image criteria for in vivo epidural space identification are high sensitivity (0.867 to 0.965) and high specificity (0.838 to 0.935). The mean value of the average signal intensities exhibits statistically significant differences (P &lt; 0.01) and a high discriminatory capacity (area under curve = 0.88) between the epidural space and the outside tissues. Conclusions: This is the first study to introduce a SSOCT fiber probe embedded in a standard epidural needle. The authors anticipate that this technique will reduce the occurrence of failed epidural blocks and other complications such as dural punctures.

scholarly journals Estimation of aerosol water and chemical composition from AERONET at Cabauw, the Netherlands

2013 ◽  
Vol 13 (6) ◽  
pp. 15191-15232 ◽  
Author(s):  
A. J. van Beelen ◽  
G. J. H. Roelofs ◽  
O. P. Hasekamp ◽  
J. S. Henzing ◽  
T. Röckmann
Keyword(s):  
Refractive Index ◽  
Chemical Composition ◽  
Relative Humidity ◽  
The Netherlands ◽  
Size Distribution ◽  
Volume Fraction ◽  
Dry Mass ◽  
Water Volume ◽  
Aerosol Composition ◽  
Water Volume Fraction

Abstract. Remote sensing of aerosols provides important information on the atmospheric aerosol abundance. However, due to the hygroscopic nature of aerosol particles observed aerosol optical properties are influenced by atmospheric humidity, and the measurements do not unambiguously characterize the aerosol dry mass and composition which complicates the comparison with aerosol models. In this study we derive aerosol water and chemical composition by a modeling approach that combines individual measurements of remotely sensed aerosol properties (e.g. optical thickness, single scattering albedo, refractive index and size distribution) from an AERONET (Aerosol Robotic Network) sun-photometer with radiosonde measurements of relative humidity. The model simulates water uptake by aerosols based on the chemical composition and size distribution. A minimization method is used to calculate aerosol composition and concentration, which are then compared to in situ measurements from the Intensive Measurement Campaign At the Cabauw Tower (IMPACT, May 2008, the Netherlands). Computed concentrations show reasonable agreement with surface observations and follow the day-to-day variability in observations. Total dry mass (33 ± 12 μg m−3) and black carbon concentrations (0.7 ± 0.3 μg m−3) are generally accurately computed. The uncertainty in the AERONET (real) refractive index (0.025–0.05) introduces larger uncertainty in the modeled aerosol composition (e.g. sulfates, ammonium nitrate or organic matter) and leads to an uncertainty of 0.1–0.25 in aerosol water volume fraction. Water volume fraction is highly variable depending on composition, up to >0.5 at 70–80% and <0.1 at 40% relative humidity.

scholarly journals Estimation of aerosol water and chemical composition from AERONET Sun–sky radiometer measurements at Cabauw, the Netherlands

2014 ◽  
Vol 14 (12) ◽  
pp. 5969-5987 ◽  
Author(s):  
A. J. van Beelen ◽  
G. J. H. Roelofs ◽  
O. P. Hasekamp ◽  
J. S. Henzing ◽  
T. Röckmann
Keyword(s):  
Refractive Index ◽  
Organic Matter ◽  
Chemical Composition ◽  
Relative Humidity ◽  
Volume Fraction ◽  
Inorganic Salts ◽  
Water Volume ◽  
Aerosol Composition ◽  
Water Volume Fraction ◽  
The Individual

Abstract. Remote sensing of aerosols provides important information on atmospheric aerosol abundance. However, due to the hygroscopic nature of aerosol particles observed aerosol optical properties are influenced by atmospheric humidity, and the measurements do not unambiguously characterize the aerosol dry mass and composition, which complicates the comparison with aerosol models. In this study we derive aerosol water and chemical composition by a modeling approach that combines individual measurements of remotely sensed aerosol properties (e.g., optical thickness, single-scattering albedo, refractive index and size distribution) from an AERONET (Aerosol Robotic Network) Sun–sky radiometer with radiosonde measurements of relative humidity. The model simulates water uptake by aerosols based on the chemical composition (e.g., sulfates, ammonium, nitrate, organic matter and black carbon) and size distribution. A minimization method is used to calculate aerosol composition and concentration, which are then compared to in situ measurements from the Intensive Measurement Campaign At the Cabauw Tower (IMPACT, May 2008, the Netherlands). Computed concentrations show good agreement with campaign-average (i.e., 1–14 May) surface observations (mean bias is 3% for PM10 and 4–25% for the individual compounds). They follow the day-to-day (synoptic) variability in the observations and are in reasonable agreement for daily average concentrations (i.e., mean bias is 5% for PM10 and black carbon, 10% for the inorganic salts and 18% for organic matter; root-mean-squared deviations are 26% for PM10 and 35–45% for the individual compounds). The modeled water volume fraction is highly variable and strongly dependent on composition. During this campaign we find that it is >0.5 at approximately 80% relative humidity (RH) when the aerosol composition is dominated by hygroscopic inorganic salts, and <0.1 when RH is below 40%, especially when the composition is dominated by less hygroscopic compounds such as organic matter. The scattering enhancement factor (f(RH), the ratio of the scattering coefficient at 85% RH and its dry value at 676 nm) during 1–14 May is 2.6 ± 0.5. The uncertainty in AERONET (real) refractive index (0.025–0.05) is the largest source of uncertainty in the modeled aerosol composition and leads to an uncertainty of 0.1–0.25 (50–100%) in aerosol water volume fraction. Our methodology performs relatively well at Cabauw, but a better performance may be expected for regions with higher aerosol loading where the uncertainties in the AERONET inversions are smaller.

Cyclosporin A-loaded poly(d,l-lactide) nanoparticles: a promising tool for treating alopecia

Nanomedicine ◽  
2020 ◽  
Vol 15 (15) ◽  
pp. 1459-1469
Author(s):  
Bruno Fernandes ◽  
Teresa Matamá ◽  
Andreia C. Gomes ◽  
Artur Cavaco-Paulo
Keyword(s):  
Cyclosporin A ◽  
Ex Vivo ◽  
Skin Permeation ◽  
Hair Follicles ◽  
Porcine Skin ◽  
Skin Cell ◽  
Promising Tool ◽  
Physicochemical Stability ◽  
New Strategy

Background: Alopecia treatments are scarce and lack efficacy. Cyclosporin A (CsA) has hair growth-inducing properties but its poor cutaneous absorption undermines its use in topical treatments. Aim: Development of a new potential topical treatment of alopecia with CsA. Materials & methods: CsA-loaded poly(d,l-lactide) (PLA) nanoparticles were obtained and characterized. Skin permeation was evaluated in ex vivo porcine skin. Results: Nanoparticles with good physicochemical stability increased CsA skin permeation/hair follicles accumulation, compared with a noncolloidal formulation. CsA biocompatibility in NCTC2455 keratinocytes (reference skin cell line) was clearly improved when encapsulated in PLA nanoparticles. Conclusion: This work fosters further in vivo investigation of CsA-loaded PLA nanoparticles as a promising new strategy to treat alopecia, a very traumatic, possibly autoimmune, disease.

Universally Applicable Fabrication Technique for Biomimetic Nanocone Arrays on Flexible Polymer Substrates for Anti-Reflection Functionality

2019 ◽  
Vol 7 (4) ◽  
Author(s):  
Yupeng Li ◽  
Xia Liu ◽  
Xiaoyu Li ◽  
Bao Zhu ◽  
Mingkai Lei ◽  
...  
Keyword(s):  
Refractive Index ◽  
Volume Fraction ◽  
Incidence Angle ◽  
Incident Light ◽  
Oxygen Plasma Treatment ◽  
Chemical Compositions ◽  
Refractive Index Gradient ◽  
Polymer Substrates ◽  
Flexible Polymer ◽  
Fluorocarbon Polymer

Abstract Inspired by the anti-reflection functionality of cicada wings decorated with nanocone arrays, a facile technique to endow flexible polymer substrates of diverse chemical compositions with the same functionalities has been devised. In this universally applicable two-step technique based on a capacitatively coupled radiofrequency plasma (CCRP), first oxygen-plasma treatment (OPT) is implemented to grow arrays of vertical elongated nanostructures with almost uniform cross-sectional diameter of the polymer substrate, and then fluorocarbon polymer deposition (FPD) is carried out so that the nanostructures evolve into nanocones with small apex angle. The dependence of ion-bombardment-induced sputtering on the local impingement angle of ions taper the vertical nanostructures into the nanocones during the FPD under CCRP. The nanocone arrays exhibit low specular reflectance in a broad wavelength range and a wide incidence angle range that is quite insensitive to the polarization state of the incident light. The effective refractive index gradient of irregularly arranged nanocone arrays is characterized from the refractive index of the fluorocarbon polymer and the volume fraction considering the nanocone probability with the Gaussian distribution. The excellent broadband and omnidirectional anti-reflection properties are in consequence of a graded refractive index.

The Role of Polyphenols in the Modulation of Plasma Non-Enzymatic Antioxidant Capacity (NEAC)

2012 ◽  
Vol 82 (3) ◽  
pp. 228-232 ◽  
Author(s):  
Mauro Serafini ◽  
Giuseppa Morabito
Keyword(s):  
Antioxidant Capacity ◽  
Dietary Intervention ◽  
Ex Vivo ◽  
The Body ◽  
Dietary Polyphenols ◽  
Enzymatic Antioxidant ◽  
Endogenous Antioxidant

Dietary polyphenols have been shown to scavenge free radicals, modulating cellular redox transcription factors in different in vitro and ex vivo models. Dietary intervention studies have shown that consumption of plant foods modulates plasma Non-Enzymatic Antioxidant Capacity (NEAC), a biomarker of the endogenous antioxidant network, in human subjects. However, the identification of the molecules responsible for this effect are yet to be obtained and evidences of an antioxidant in vivo action of polyphenols are conflicting. There is a clear discrepancy between polyphenols (PP) concentration in body fluids and the extent of increase of plasma NEAC. The low degree of absorption and the extensive metabolism of PP within the body have raised questions about their contribution to the endogenous antioxidant network. This work will discuss the role of polyphenols from galenic preparation, food extracts, and selected dietary sources as modulators of plasma NEAC in humans.

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