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Sample records for nonlinear skin effect

  1. Analysis of Conductor Impedances Accounting for Skin Effect and Nonlinear Permeability

    Energy Technology Data Exchange (ETDEWEB)

    Perkins, M P; Ong, M M; Brown, C G; Speer, R D

    2011-07-20

    It is often necessary to protect sensitive electrical equipment from pulsed electric and magnetic fields. To accomplish this electromagnetic shielding structures similar to Faraday Cages are often implemented. If the equipment is inside a facility that has been reinforced with rebar, the rebar can be used as part of a lighting protection system. Unfortunately, such shields are not perfect and allow electromagnetic fields to be created inside due to discontinuities in the structure, penetrations, and finite conductivity of the shield. In order to perform an analysis of such a structure it is important to first determine the effect of the finite impedance of the conductors used in the shield. In this paper we will discuss the impedances of different cylindrical conductors in the time domain. For a time varying pulse the currents created in the conductor will have different spectral components, which will affect the current density due to skin effects. Many construction materials use iron and different types of steels that have a nonlinear permeability. The nonlinear material can have an effect on the impedance of the conductor depending on the B-H curve. Although closed form solutions exist for the impedances of cylindrical conductors made of linear materials, computational techniques are needed for nonlinear materials. Simulations of such impedances are often technically challenging due to the need for a computational mesh to be able to resolve the skin depths for the different spectral components in the pulse. The results of such simulations in the time domain will be shown and used to determine the impedances of cylindrical conductors for lightning current pulses that have low frequency content.

  2. Nonlinear stochastic system identification of skin using volterra kernels.

    Science.gov (United States)

    Chen, Yi; Hunter, Ian W

    2013-04-01

    Volterra kernel stochastic system identification is a technique that can be used to capture and model nonlinear dynamics in biological systems, including the nonlinear properties of skin during indentation. A high bandwidth and high stroke Lorentz force linear actuator system was developed and used to test the mechanical properties of bulk skin and underlying tissue in vivo using a non-white input force and measuring an output position. These short tests (5 s) were conducted in an indentation configuration normal to the skin surface and in an extension configuration tangent to the skin surface. Volterra kernel solution methods were used including a fast least squares procedure and an orthogonalization solution method. The practical modifications, such as frequency domain filtering, necessary for working with low-pass filtered inputs are also described. A simple linear stochastic system identification technique had a variance accounted for (VAF) of less than 75%. Representations using the first and second Volterra kernels had a much higher VAF (90-97%) as well as a lower Akaike information criteria (AICc) indicating that the Volterra kernel models were more efficient. The experimental second Volterra kernel matches well with results from a dynamic-parameter nonlinearity model with fixed mass as a function of depth as well as stiffness and damping that increase with depth into the skin. A study with 16 subjects showed that the kernel peak values have mean coefficients of variation (CV) that ranged from 3 to 8% and showed that the kernel principal components were correlated with location on the body, subject mass, body mass index (BMI), and gender. These fast and robust methods for Volterra kernel stochastic system identification can be applied to the characterization of biological tissues, diagnosis of skin diseases, and determination of consumer product efficacy.

  3. Nonlinear effects in optical fibers

    CERN Document Server

    Ferreira, Mario F

    2011-01-01

    Cutting-edge coverage of nonlinear phenomena occurring inside optical fibers Nonlinear fiber optics is a specialized part of fiber optics dealing with optical nonlinearities and their applications. As fiber-optic communication systems have become more advanced and complex, the nonlinear effects in optical fibers have increased in importance, as they adversely affect system performance. Paradoxically, the same nonlinear phenomena also offer the promise of addressing the bandwidth bottleneck for signal processing for future ultra-high speed optical networks. Nonlinear Effects in Optical Fiber

  4. In vivo characterization of skin using a Weiner nonlinear stochastic system identification method.

    Science.gov (United States)

    Chen, Yi; Hunter, Ian W

    2009-01-01

    This paper describes an indentometer device used to identify the linear dynamic and nonlinear properties of skin and underlying tissue using an in vivo test. The device uses a Lorentz force actuator to apply a dynamic force to the skin and measures the resulting displacement. It was found that the skin could be modeled as a Wiener system (i.e. a linear dynamic system followed by a static nonlinearity). Using a stochastic nonlinear system identification technique, the method presented in this paper was able to identify the dynamic linear and static nonlinear mechanical parameters of the indentometer-skin system within 2 to 4 seconds. The shape of the nonlinearity was found to vary depending on the area of the skin that was tested. We show that the device can repeatably distinguish between different areas of human tissue for multiple test subjects.

  5. Nonlinear Peltier effect in semiconductors

    Science.gov (United States)

    Zebarjadi, Mona; Esfarjani, Keivan; Shakouri, Ali

    2007-09-01

    Nonlinear Peltier coefficient of a doped InGaAs semiconductor is calculated numerically using the Monte Carlo technique. The Peltier coefficient is also obtained analytically for single parabolic band semiconductors assuming a shifted Fermi-Dirac electronic distribution under an applied bias. Analytical results are in agreement with numerical simulations. Key material parameters affecting the nonlinear behavior are doping concentration, effective mass, and electron-phonon coupling. Current density thresholds at which nonlinear behavior is observable are extracted from numerical data. It is shown that the nonlinear Peltier effect can be used to enhance cooling of thin film microrefrigerator devices especially at low temperatures.

  6. Skin Exposures & Effects in the Workplace

    Science.gov (United States)

    ... Topics Publications and Products Programs Contact NIOSH NIOSH SKIN EXPOSURES & EFFECTS Recommend on Facebook Tweet Share Compartir ... currently lacking for measuring and assessing skin exposures. Skin Notation (SK) Profiles NIOSH has developed a strategy ...

  7. An effective skin integrity program.

    Science.gov (United States)

    Banks, K; Jones, E S; Law, M S; MacAvoy, S

    1993-01-01

    Nursing staff development personnel are responsible for increasing the awareness of nursing staff of the problems caused by pressure ulcers and for supplying them with information needed for prevention and treatment. In answer to one hospital's needs, a hospital-wide, nurse-initiated, nurse-managed skin integrity program was developed and instituted. Protocols for treatment were standardized according to the latest concepts in wound healing. Basic components of the program were included in a comprehensive but succinct reference manual available on each nursing unit. Strategies for implementation were carefully planned to include feedback, approval, and support of selected physicians and nurses. Key for an effective, ongoing skin integrity program are the skin integrity clinicians and educated, confident, and enthusiastic staff nurses. Throughout the process of introducing this program, education of various groups of health-care professionals--physicians, staff nurses, skin integrity clinicians--by the Nursing Staff Development Department was pivotal in achieving a relatively smooth implementation of the program. Outcomes have demonstrated the success of this skin integrity program to both patients and staff. Creative planning, diligent research, skillful organization, and credibility of the specialists in the Nursing Staff Development Department were important elements in the development, implementation, and success of this skin integrity program.

  8. Nonlinear effects in Thomson backscattering

    Science.gov (United States)

    Maroli, C.; Petrillo, V.; Tomassini, P.; Serafini, L.

    2013-03-01

    We analyze the nonlinear classical effects of the X/γ radiation produced by Thomson/Compton sources. We confirm the development of spectral fringes of the radiation on axis, which comports broadening, shift, and deformation of the spectrum. For the nominal parameters of the SPARC-LAB Thomson scattering and of the European Proposal for the gamma source ELI-NP, however, the radiation, when collected in the suitable acceptance angle, does not reveal many differences from that predicted by the linear model and the nonlinear redshift is subdominant with respect to the quantum recoil. An experiment aimed to the study of the nonlinearities is proposed on the SPARC-LAB source.

  9. Nonlinear effects in asymmetric catalysis.

    Science.gov (United States)

    Satyanarayana, Tummanapalli; Abraham, Susan; Kagan, Henri B

    2009-01-01

    There is a need for the preparation of enantiomerically pure compounds for various applications. An efficient approach to achieve this goal is asymmetric catalysis. The chiral catalyst is usually prepared from a chiral auxiliary, which itself is derived from a natural product or by resolution of a racemic precursor. The use of non-enantiopure chiral auxiliaries in asymmetric catalysis seems unattractive to preparative chemists, since the anticipated enantiomeric excess (ee) of the reaction product should be proportional to the ee value of the chiral auxiliary (linearity). In fact, some deviation from linearity may arise. Such nonlinear effects can be rich in mechanistic information and can be synthetically useful (asymmetric amplification). This Review documents the advances made during the last decade in the use of nonlinear effects in the area of organometallic and organic catalysis.

  10. Hall effect accompanying a static skin effect

    Energy Technology Data Exchange (ETDEWEB)

    Volkenshtein, N.V.; Marchenkov, V.V.; Startsev, V.E.; Cherepanov, A.N.; Glin' skii, M.

    1985-05-10

    The Hall effect and the magnetoresistance of tungsten single crystals with rho/sub 293K//rho/sub 4.2K/ = 80 000 have been measured at 4.2 K in magnetic fields up to 150 kOe. The results reveal that a static skin effect gives rise to an anomalously pronounced increase in the Hall coefficient.

  11. Understanding nonlinear effects and losses

    Energy Technology Data Exchange (ETDEWEB)

    Irwin, J.

    1995-10-01

    With the planned construction of a large hadron collider (LHC) and a major upgrade of LEP (LEP-II) at CERN, a {Phi}-factory at Frascatti, and B-factories at SLAC (PEP-II) and KEK (KEK-B), we are now entering new energy and intensity regimes in both electron and proton circular colliders. Understanding and accurately estimating dynamic apertures and particle loss rates under both injection and colliding beam conditions is of primary importance. This paper summarizes discussions on Understanding Nonlinear Effects and Losses that took place in Working Group Three at the September 1994 Conference on Nonlinear Dynamics in Particle Accelerators at Arcidosso, Italy. Questions addressed were: {open_quotes}What do simulations indicate as the underlying causes of particle loss?{close_quotes} and {open_quotes}Do experiments agree with simulations-and if not, why not?{close_quotes} Special attention was given to a discrepancy between dynamic aperture measurements and theoretical predictions at HERA.

  12. Nonlinear Effects in the Cosmic Microwave Background

    CERN Document Server

    Maartens, R

    2000-01-01

    Major advances in the observation and theory of cosmic microwave background anisotropies have opened up a new era in cosmology. This has encouraged the hope that the fundamental parameters of cosmology will be determined to high accuracy in the near future. However, this optimism should not obscure the ongoing need for theoretical developments that go beyond the highly successful but simplified standard model. Such developments include improvements in observational modelling (e.g. foregrounds, non-Gaussian features), extensions and alternatives to the simplest inflationary paradigm (e.g. non-adiabatic effects, defects), and investigation of nonlinear effects. In addition to well known nonlinear effects such as the Rees-Sciama and Ostriker-Vishniac effects, further nonlinear effects have recently been identified. These include a Rees-Sciama-type tensor effect, time-delay effects of scalar and tensor lensing, nonlinear Thomson scattering effects and a nonlinear shear effect. Some of the nonlinear effects and th...

  13. Stochastic system identification of skin properties: linear and wiener static nonlinear methods.

    Science.gov (United States)

    Chen, Yi; Hunter, Ian W

    2012-10-01

    Wiener static nonlinear system identification was used to study the linear dynamics and static nonlinearities in the response of skin and underlying tissue under indentation in vivo. A device capable of measuring the dynamic mechanical properties of bulk skin tissue was developed and it incorporates a custom-built Lorentz force actuator that measures the dynamic compliance between the input force (system identification technique produced a variance accounted for (VAF) of 75-81% and Wiener static nonlinear techniques increased the VAF by 5%. Localized linear techniques increased the VAF to 85-95% with longer tests. Indentation experiments were conducted on 16 test subjects to determine device sensitivity and repeatability. Using the device, the coefficient of variation of test metrics was found to be as low as 2% for a single test location. The measured tissue stiffness was 300 N/m near the surface and 4.5 kN/m for high compression. The damping ranged from 5 to 23 N s/m. The bulk skin properties were also shown to vary significantly with gender and body mass index. The device and techniques used in this research can be applied to consumer product analysis, medical diagnosis and tissue research.

  14. The Effective AC Response of Nonlinear Composites

    Institute of Scientific and Technical Information of China (English)

    WEI En-Bo; GU Guo-Qing

    2001-01-01

    A perturbative approach is used to study the AC response of nonlinear composite media, which obey a current-field relation of the form J = σ E + χ|E|2 E with components having nonlinear response at finite frequencies. For a sinusoidal applied field, we extend the local potential in terms of sinusoidal components at fundamental frequency and high-order harmonic frequencies to treat the nonlinear composites. For nonlinear composite media vith a low concentrations of spherical inclusions, we give the formulae of the nonlinear effective AC susceptibility χ*3ω at the third harmonic frequency.

  15. Gamma Radiation Effects on Peanut Skin Antioxidants

    OpenAIRE

    Adriano Costa de Camargo; Thais Maria Ferreira de Souza Vieira; Marisa Aparecida Bismara Regitano-D’Arce; Maria Antonia Calori-Domingues; Solange Guidolin Canniatti-Brazaca

    2012-01-01

    Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to...

  16. Multidirectional In Vivo Characterization of Skin Using Wiener Nonlinear Stochastic System Identification Techniques.

    Science.gov (United States)

    Parker, Matthew D; Jones, Lynette A; Hunter, Ian W; Taberner, A J; Nash, M P; Nielsen, P M F

    2017-01-01

    A triaxial force-sensitive microrobot was developed to dynamically perturb skin in multiple deformation modes, in vivo. Wiener static nonlinear identification was used to extract the linear dynamics and static nonlinearity of the force-displacement behavior of skin. Stochastic input forces were applied to the volar forearm and thenar eminence of the hand, producing probe tip perturbations in indentation and tangential extension. Wiener static nonlinear approaches reproduced the resulting displacements with variances accounted for (VAF) ranging 94-97%, indicating a good fit to the data. These approaches provided VAF improvements of 0.1-3.4% over linear models. Thenar eminence stiffness measures were approximately twice those measured on the forearm. Damping was shown to be significantly higher on the palm, whereas the perturbed mass typically was lower. Coefficients of variation (CVs) for nonlinear parameters were assessed within and across individuals. Individual CVs ranged from 2% to 11% for indentation and from 2% to 19% for extension. Stochastic perturbations with incrementally increasing mean amplitudes were applied to the same test areas. Differences between full-scale and incremental reduced-scale perturbations were investigated. Different incremental preloading schemes were investigated. However, no significant difference in parameters was found between different incremental preloading schemes. Incremental schemes provided depth-dependent estimates of stiffness and damping, ranging from 300 N/m and 2 Ns/m, respectively, at the surface to 5 kN/m and 50 Ns/m at greater depths. The device and techniques used in this research have potential applications in areas, such as evaluating skincare products, assessing skin hydration, or analyzing wound healing.

  17. Effect of bicellar systems on skin properties.

    Science.gov (United States)

    Barbosa-Barros, L; Barba, C; Cócera, M; Coderch, L; López-Iglesias, C; de la Maza, A; López, O

    2008-03-20

    Bicelles are discoidal aggregates formed by a flat dimyristoyl-glycero-phosphocholine (DMPC) bilayer, stabilized by a rim of dihexanoyl-glycero-phosphocholine (DHPC) in water. Given the structure, composition and the dimensions of these aggregates around 10-50 nm diameter, their use for topical applications is a promising strategy. This work evaluates the effect of DMPC/DHPC bicelles with molar ratio (2/1) on intact skin. Biophysical properties of the skin, such as transepidermal water loss (TEWL), elasticity, skin capacitance and irritation were measured in healthy skin in vivo. To study the effect of the bicellar systems on the microstructure of the stratum corneum (SC) in vitro, pieces of native tissue were treated with the aforementioned bicellar system and evaluated by freeze substitution applied to transmission electron microscopy (FSTEM). Our results show that bicelles increase the TEWL, the skin elastic parameters and, decrease skin hydration without promoting local signs of irritation and without affecting the SC lipid microstructure. Thus, a permeabilizing effect of bicelles on the skin takes place possibly due to the changes in the phase behaviour of the SC lipids by effect of phospholipids from bicelles.

  18. The skin effect: a fresh look

    Science.gov (United States)

    Mathew, Vincent; Arun, P.

    2017-07-01

    Based on network analysis, a simple method has been suggested to explain the skin effect to undergraduate students. The mathematics required is an elementary idea of calculus giving a surprising insight into how nature behaves.

  19. Cosmological effects of nonlinear electrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Novello, M [Instituto de Cosmologia Relatividade Astrofisica (ICRA-Brasil/CBPF), Rua Dr Xavier Sigaud, 150, CEP 22290-180, Rio de Janeiro (Brazil); Goulart, E [Instituto de Cosmologia Relatividade Astrofisica (ICRA-Brasil/CBPF), Rua Dr Xavier Sigaud, 150, CEP 22290-180, Rio de Janeiro (Brazil); Salim, J M [Instituto de Cosmologia Relatividade Astrofisica (ICRA-Brasil/CBPF), Rua Dr Xavier Sigaud, 150, CEP 22290-180, Rio de Janeiro (Brazil); Bergliaffa, S E Perez [Departamento de Fisica Teorica, Universidade do Estado do Rio de Janeiro, R. Sao Francisco Xavier, 524, Maracana, CEP 20559-900, Rio de Janeiro (Brazil)

    2007-06-07

    It will be shown that a given realization of nonlinear electrodynamics, used as a source of Einstein's equations, generates a cosmological model with interesting features, namely a phase of current cosmic acceleration, and the absence of an initial singularity, thus pointing to a way of solving two important problems in cosmology.

  20. Gamma Radiation Effects on Peanut Skin Antioxidants

    Directory of Open Access Journals (Sweden)

    Adriano Costa de Camargo

    2012-03-01

    Full Text Available Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to refined-bleached-deodorized (RBD soybean oil. The oxidative stability of the oil samples was determined using the Oil Stability Index method and compared to a control and synthetic antioxidants (100 mg/kg BHT and 200 mg/kg TBHQ. Gamma radiation changed total phenolic content, total condensed tannins, total flavonoid content, and the antioxidant activity. All extracts, gamma irradiated or not, presented increasing induction period (h, measured by the Oil Stability Index method, when compared with the control. Antioxidant activity of the peanut skins was higher than BHT. The present study confirmed that gamma radiation did not affect the peanut skin extracts’ antioxidative properties when added to soybean oil.

  1. Gamma radiation effects on peanut skin antioxidants.

    Science.gov (United States)

    de Camargo, Adriano Costa; de Souza Vieira, Thais Maria Ferreira; Regitano-D'Arce, Marisa Aparecida Bismara; Calori-Domingues, Maria Antonia; Canniatti-Brazaca, Solange Guidolin

    2012-01-01

    Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to refined-bleached-deodorized (RBD) soybean oil. The oxidative stability of the oil samples was determined using the Oil Stability Index method and compared to a control and synthetic antioxidants (100 mg/kg BHT and 200 mg/kg TBHQ). Gamma radiation changed total phenolic content, total condensed tannins, total flavonoid content, and the antioxidant activity. All extracts, gamma irradiated or not, presented increasing induction period (h), measured by the Oil Stability Index method, when compared with the control. Antioxidant activity of the peanut skins was higher than BHT. The present study confirmed that gamma radiation did not affect the peanut skin extracts' antioxidative properties when added to soybean oil.

  2. Effective ac response in weakly nonlinear composites

    Energy Technology Data Exchange (ETDEWEB)

    Wei Enbo [Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Yang Zidong [College of Power Engineering, University of Shanghai Science and Technology, Shanghai 200093 (China); Gu Guoqing [Information College of Science and Technology, East China Normal University, Shanghai 200062 (China)

    2004-01-07

    The perturbation method is developed to deal with the problem of determining the effective nonlinear conductivity of Kerr-like nonlinear media under an external ac electric field. As an example, we have considered the cylindrical inclusion embedded in a host under the sinusoidal external field E{sub 1} sin (<{omega}t) + E{sub 3} sin (3<{omega}t) with frequencies{omega} and 3{omega}. The potentials of composites at higher harmonics are derived in both local inclusion particle and host regions. The effective responses of bulk nonlinear composites at basic frequency and harmonics are given for cylindrical composites in the dilute limit. Moreover, the relationships between the nonlinear effective responses at the basic frequency and the third harmonics are derived.

  3. Enhanced Nonlinear Effects in Metamaterials and Plasmonics

    Directory of Open Access Journals (Sweden)

    C. Argyropoulos

    2012-07-01

    Full Text Available In this paper we provide an overview of the anomalous and enhanced nonlinear effects available when optical nonlinear materials are combined inside plasmonic waveguide structures. Broad, bistable and all-optical switching responses are exhibited at the cut-off frequency of these waveguides, characterized by reduced Q-factor resonances. These phenomena are due to the large field enhancement obtained inside specific plasmonic gratings, which ensures a significant boosting of the nonlinear operation. Several exciting applications are proposed, which may potentially lead to new optical components and add to the optical nanocircuit paradigm.

  4. Gamma radiation effects on peanut skin antioxidants

    Energy Technology Data Exchange (ETDEWEB)

    Camargo, Adriano Costa de [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Canniatti-Brazaca, Solange Guidolin; Vieira, Thais Maria Ferreira de Souza; Regitano-d' Arce, Marisa Aparecida Bismara; Calori-Domingues, Maria Antonia, E-mail: sgcbraza@usp.b, E-mail: tvieira@esalq.usp.b, E-mail: mabra@esalq.usp.b, E-mail: macdomin@esalq.usp.b [Escola Superior de Agricultura Luiz de Queiroz (ESALQ/USP), Piracicaba, SP (Brazil). Dept. de Agroindustria, Alimentos e Nutricao

    2011-07-01

    Peanut skin, which is removed in the peanut blanching process, is rich in bioactive compounds with antioxidant properties. The viability of using natural sources of antioxidants to replace synthetic antioxidants was assessed. The aims of this study were to measure bioactive compounds in peanut skins and evaluate the effect of gamma radiation on their antioxidant activity. Peanut skin samples were treated with 0.0, 5.0, 7.5, or 10.0 kGy gamma rays at a dose rate of 7.5 kGy/h using a {sup 60}Co source. Total phenolics, condensed tannins, total flavonoids, and antioxidant activity were evaluated. Extracts obtained from the peanut skins were added to refined-bleached deodorized (RBD) soybean oil that was free from synthetic antioxidants. The oxidative stability of the oil samples was determined using the Rancimat method and compared to a control and synthetic antioxidants (100 mg/kg BHT and 200 mg/kg TBHQ). Gamma radiation changed total phenolic content, total condensed tannins, total flavonoid content, and the antioxidant activity. Ethanolic extracts, gamma irradiated or not, presented increasing induction period (h), measured by the Rancimat method, when compared with the control. Antioxidant activity of the peanut skins was higher than BHT but lower than THBQ. The present study confirmed that gamma radiation did not affect the peanut skin extracts' antioxidative level when added to soybean oil. The induction period of the control soybean oil was 5.7 h, while soybean oil with added ethanolic peanut skin extract had an induction period of 7.2 h, on average. (author)

  5. Recent Issues on Nonlinear Effects in Optical Fibers

    Institute of Scientific and Technical Information of China (English)

    Takashi; Inoue; Osamu; Aso; Shu; Namiki

    2003-01-01

    This talk will discuss the types of optical signal degradation due to fiber nonlinearity and review recently invented fibers for suppressing the effects. It also introduces efficiency of highly nonlinear fibers and their applications to nonlinear signal processing.

  6. Role of antioxidants in the skin: anti-aging effects.

    Science.gov (United States)

    Masaki, Hitoshi

    2010-05-01

    Intracellular and extracellular oxidative stress initiated by reactive oxygen species (ROS) advance skin aging, which is characterized by wrinkles and atypical pigmentation. Because UV enhances ROS generation in cells, skin aging is usually discussed in relation to UV exposure. The use of antioxidants is an effective approach to prevent symptoms related to photo-induced aging of the skin. In this review, the mechanisms of ROS generation and ROS elimination in the body are summarized. The effects of ROS generated in the skin and the roles of ROS in altering the skin are also discussed. In addition, the effects of representative antioxidants on the skin are summarized with a focus on skin aging.

  7. Quantum Information Processing using Nonlinear Optical Effects

    DEFF Research Database (Denmark)

    Andersen, Lasse Mejling

    of the converted idler depends on the other pump. This allows for temporal-mode-multiplexing. When the effects of nonlinear phase modulation (NPM) are included, the phases of the natural input and output modes are changed, reducing the separability. These effects are to some degree mediated by pre......This PhD thesis treats applications of nonlinear optical effects for quantum information processing. The two main applications are four-wave mixing in the form of Bragg scattering (BS) for quantum-state-preserving frequency conversion, and sum-frequency generation (SFG) in second-order nonlinear...... to obtain a 100 % conversion efficiency is to use multiple stages of frequency conversion, but this setup suffers from the combined effects of NPM. This problem is circumvented by using asymmetrically pumped BS, where one pump is continuous wave. For this setup, NPM is found to only lead to linear phase...

  8. Shark skin effect in creeping films

    CERN Document Server

    Scholle, M

    2006-01-01

    If a body in a stream is provided with small ridges aligned in the local flow direction, a remarkable drag reduction can be reached under turbulent flow conditions. This surprising phenomenon is called the 'shark skin effect'. We demonstrate, that a reduction of resistance can also be reached in creeping flows if the ridges are aligned perpendicular to the flow direction. We especially consider in gravity-driven film flows the effect of the bottom topography on the mean transport velocity.

  9. Effect of interstitial low level laser stimulation in skin density

    Science.gov (United States)

    Jang, Seulki; Ha, Myungjin; Lee, Sangyeob; Yu, Sungkon; Park, Jihoon; Radfar, Edalat; Hwang, Dong Hyun; Lee, Han A.; Kim, Hansung; Jung, Byungjo

    2016-03-01

    As the interest in skin was increased, number of studies on skin care also have been increased. The reduction of skin density is one of the symptoms of skin aging. It reduces elasticity of skin and becomes the reason of wrinkle formation. Low level laser therapy (LLLT) has been suggested as one of the effective therapeutic methods for skin aging as in hasten to change skin density. This study presents the effect of a minimally invasive laser needle system (MILNS) (wavelength: 660nm, power: 20mW) in skin density. Rabbits were divided into three groups. Group 1 didn't receive any laser stimulation as a control group. Group 2 and 3 as test groups were exposed to MILNS with energy of 8J and 6J on rabbits' dorsal side once a week, respectively. Skin density of rabbits was measured every 12 hours by using an ultrasound skin scanner.

  10. Noninvasive label-free monitoring of cosmetics and pharmaceuticals in human skin using nonlinear optical microscopy (Conference Presentation)

    Science.gov (United States)

    Osseiran, Sam; Wang, Hequn; Evans, Conor L.

    2017-02-01

    Over the past decade, nonlinear optical microscopy has seen a dramatic rise in its use in research settings due to its noninvasiveness, enhanced penetration depth, intrinsic optical sectioning, and the ability to probe chemical compounds with molecular specificity without exogenous contrast agents. Nonlinear optical techniques including two-photon excitation fluorescence (2PEF), fluorescence lifetime imaging microscopy (FLIM), second harmonic generation (SHG), coherent anti-Stokes and stimulated Raman scattering (CARS and SRS, respectively), as well as transient and sum frequency absorption (TA and SFA, respectively), have been widely used to explore the physiology and microanatomy of skin. Recently, these modalities have shed light on dermal processes that could not have otherwise been observed, including the spatiotemporal monitoring of cosmetics and pharmaceuticals. However, a challenge quickly arises when studying such chemicals in a dermatological context: many exogenous compounds have optical signatures that can interfere with the signals that would otherwise be acquired from intact skin. For example, oily solvents exhibit strong signals when probing CH2 vibrations with CARS/SRS; chemical sun filters appear bright in 2PEF microscopy; and darkly colored compounds readily absorb light across a broad spectrum, producing strong TA/SFA signals. Thus, this discussion will first focus on the molecular contrast in skin that can be probed using the aforementioned nonlinear optical techniques. This will be followed by an overview of strategies that take advantage of the exogenous compounds' optical signatures to probe spatiotemporal dynamics while preserving endogenous information from skin.

  11. Nonlinear Dispersion Effect on Wave Transformation

    Institute of Scientific and Technical Information of China (English)

    LI Ruijie; Dong-Young LEE

    2000-01-01

    A new nonlinear dispersion relation is given in this paper, which can overcome the limitation of the intermediate minimum value in the dispersion relation proposed by Kirby and Dalrymple (1986), and which has a better approximation to Hedges' empirical relation than the modilied relations by Hedges (1987). Kirby and Dahymple (1987) for shallow waters. The new dispersion relation is simple in form. thus it can be used easily in practice. Meanwhile. a general explicil approximalion to the new dispersion rela tion and olher nonlinear dispersion relations is given. By use of the explicit approximation to the new dispersion relation along with the mild slope equation taking inlo account weakly nonlinear effect, a mathematical model is obtained, and it is applied to laboratory data. The results show that the model developed vith the new dispersion relation predicts wave translornation over complicated topography quite well.

  12. Rotational Doppler effect in nonlinear optics

    Science.gov (United States)

    Li, Guixin; Zentgraf, Thomas; Zhang, Shuang

    2016-08-01

    The translational Doppler effect of electromagnetic and sound waves has been successfully applied in measurements of the speed and direction of vehicles, astronomical objects and blood flow in human bodies, and for the Global Positioning System. The Doppler effect plays a key role for some important quantum phenomena such as the broadened emission spectra of atoms and has benefited cooling and trapping of atoms with laser light. Despite numerous successful applications of the translational Doppler effect, it fails to measure the rotation frequency of a spinning object when the probing wave propagates along its rotation axis. This constraint was circumvented by deploying the angular momentum of electromagnetic waves--the so-called rotational Doppler effect. Here, we report on the demonstration of rotational Doppler shift in nonlinear optics. The Doppler frequency shift is determined for the second harmonic generation of a circularly polarized beam passing through a spinning nonlinear optical crystal with three-fold rotational symmetry. We find that the second harmonic generation signal with circular polarization opposite to that of the fundamental beam experiences a Doppler shift of three times the rotation frequency of the optical crystal. This demonstration is of fundamental significance in nonlinear optics, as it provides us with insight into the interaction of light with moving media in the nonlinear optical regime.

  13. Nonlinear peltier effect in quantum point contacts

    Science.gov (United States)

    Bogachek, E. N.; Scherbakov, A. G.; Landman, Uzi

    1998-11-01

    A theoretical analysis of the Peltier effect in two-dimensional quantum point contacts, in field-free conditions and under the influence of applied magnetic fields, is presented. It is shown that in the nonlinear regime (finite applied voltage) new peaks in the Peltier coefficient appear leading to violation of Onsager's relation. Oscillations of the Peltier coefficient in a magnetic field are demonstrated.

  14. Topological nature of nonlinear optical effects in solids

    OpenAIRE

    Morimoto, Takahiro; Nagaosa, Naoto

    2015-01-01

    There are a variety of nonlinear optical effects including higher harmonic generations, photovoltaic effects, and nonlinear Kerr rotations. They are realized by the strong light irradiation to materials that results in nonlinear polarizations in the electric field. These are of great importance in studying the physics of excited states of the system as well as for applications to optical devices and solar cells. Nonlinear properties of materials are usually described by the nonlinear suscepti...

  15. New nonlinear polarization effects for frequency selection

    Science.gov (United States)

    Karagodova, Tamara Y.; Karagodov, Alexander I.

    1998-05-01

    The method of computer simulations on nonlinear resonant magnetooptical effects developed for real multi-level atoms in the two laser fields of arbitrary intensity and external magnetic field is applied for the polarization effects of different types calculations and investigations of the dependence of the characteristics of these effects on magnetic field strength, intensities, polarization and detunings of laser fields for alkaline atoms. The essence of the method consists in simulations and analysis of the plots of dependence of quasi energies on parameters, which are obtained with the help of sorting subprogram, and selection of suitable algorithms for calculations of characteristics of nonlinear resonant magnetooptical effects. One photon and two photon resonant effects are investigated for wide range of magnetic field strength from Zeeman to Paschen Back effects. Some new features in the spectra of rotation of plane of polarization and circular dichroism of different types are predicted. The results show the agreement with known experiments. Such calculations of nonlinear resonant magnetooptical effects in the intense laser fields resonant to adjacent transitions and magnetic field show the opportunity of investigation the modifications of electronic structure due to intense radiation fields and strong external magnetic field in atomic gases and also may be used for the treatment of new methods of phase-polarization selection of modes of tunable lasers.

  16. Skin absorption of inorganic lead (PbO) and the effect of skin cleansers.

    Science.gov (United States)

    Filon, Francesca Larese; Boeniger, Mark; Maina, Giovanni; Adami, Gianpiero; Spinelli, Paolo; Damian, Adriano

    2006-07-01

    The aim of this study was to investigate the percutaneous penetration of lead oxide (PbO) powder and the effect of rapid skin decontamination with two different detergents. Franz cells were used to study in vitro PbO skin penetration through human skin during a 24-hour period. The tests were performed without or with decontamination using either Ivory Liquid soap or a new experimental cleanser 30 minutes after the start of exposure. We confirm that PbO can pass through the skin with a median penetration of 2.9 ng/cm (25-75th percentiles 0.35-6). The cleaning procedure using Ivory Liquid soap significantly increased skin penetration with a median value of 23.6 ng/cm (25-75th percentiles 12-47.1; Mann-Whitney U test, P = 0.0002), whereas the new experimental cleanser only marginally increased penetration (7.1 ng/cm). Our results indicate that it is necessary to prevent skin contamination from occurring because a short contact can increase skin content and penetration even if quickly followed by washing. This study demonstrated that PbO powder can pass through the skin and that skin decontamination done after 30 minutes of exposure did not decrease skin absorption occurring over 24 hours and stresses the need to prevent skin contamination when using toxic substances.

  17. Managing Chemotherapy Side Effects: Skin and Nail Changes

    Science.gov (United States)

    N ational C ancer I nstitute Managing Chemotherapy Side Effects Skin and Nail Changes “I was glad to learn that most skin and nail problems go away after treatment. For now, my nurse told me about ...

  18. Effects of thermal water on skin regeneration.

    Science.gov (United States)

    Faga, Angela; Nicoletti, Giovanni; Gregotti, Cesarina; Finotti, Valentina; Nitto, Agnese; Gioglio, Luciana

    2012-05-01

    An experimental study was carried out in an animal (New Zealand white rabbit) wound model to evaluate any effects of a hypotonic, bicarbonate-calcium-magnesium mineral water (Comano thermal water) on skin regeneration, comparing the healing rate of split-thickness skin graft donor sites treated with the thermal water wet dressing versus a standard petrolatum gauze dressing versus a saline solution wet dressing. The study was performed in two steps; an overall of 22 animals were enrolled in the study. The wound healing progress was evaluated both by the surgeons and by the histologists. Sixty-four punch biopsies were examined in all. The histological samples were examined after staining with haematoxylin and eosin, Masson's and orcein staining and under a transmission electron microscope. The data were statistically analysed. The Comano thermal water proved to improve skin regeneration, not only by increasing keratinocyte proliferation and migration but also favourably modulating the regenerated collagen and elastic fibres in the dermis. We propose that the results of the topical treatment with the thermal water could be due to the favourable combination of a local wet environment with an anti-inflammatory action and that the regenerative properties of Comano thermal water observed in rabbits could also be applied for human use.

  19. Controllable spatiotemporal nonlinear effects in multimode fibres

    Science.gov (United States)

    Wright, Logan G.; Christodoulides, Demetrios N.; Wise, Frank W.

    2015-05-01

    Multimode fibres are of interest for next-generation telecommunications systems and the construction of high-energy fibre lasers. However, relatively little work has explored nonlinear pulse propagation in multimode fibres. Here, we consider highly nonlinear ultrashort pulse propagation in the anomalous-dispersion regime of a graded-index multimode fibre. Low modal dispersion and strong nonlinear coupling between the fibre's many spatial modes result in interesting behaviour. We observe spatiotemporal effects reminiscent of nonlinear optics in bulk media—self-focusing and multiple filamentation—at a fraction of the usual power. By adjusting the spatial initial conditions, we generate on-demand, megawatt, ultrashort pulses tunable between 1,550 and 2,200 nm dispersive waves over one octave; intense combs of visible light; and a multi-octave-spanning supercontinuum. Our results indicate that multimode fibres present unique opportunities for observing new spatiotemporal dynamics and phenomena. They also enable the realization of a new type of tunable, broadband fibre source that could be useful for many applications.

  20. Dynamical effects of overparametrization in nonlinear models

    Science.gov (United States)

    Aguirre, Luis Antonio; Billings, S. A.

    1995-01-01

    This paper is concemed with dynamical reconstruction for nonlinear systems. The effects of the driving function and of the complexity of a given representation on the bifurcation patter are investigated. It is shown that the use of different driving functions to excite the system may yield models with different bifurcation patterns. The complexity of the reconstructions considered is quantified by the embedding dimension and the number of estimated parameters. In this respect it appears that models which reproduce the original bifurcation behaviour are of limited complexity and that excessively complex models tend to induce ghost bifurcations and spurious dynamical regimes. Moreover, some results suggest that the effects of overparametrization on the global dynamical behaviour of a nonlinear model may be more deleterious than the presence of moderate noise levels. In order to precisely quantify the complexity of the reconstructions, global polynomials are used although the results are believed to apply to a much wider class of representations including neural networks.

  1. Pharmaceutical effect of contraceptive pills on the skin.

    Science.gov (United States)

    Foldes, E G

    1988-07-01

    Described are the various effects of birth control methods on the skin-mainly those of the contraceptive pill. The equilibrium of healthy skins and mucosa might be affected by these chemicals or pharmaceutical agents, causing different manifestations. The skin and mucosa should be looked upon as integral parts of the human body and its functions even where localized symptoms arise.

  2. Understanding engineered nanomaterial skin interactions and the modulatory effects of ultraviolet radiation skin exposure.

    Science.gov (United States)

    Jatana, Samreen; DeLouise, Lisa A

    2014-01-01

    The study of engineered nanomaterials for the development of technological applications, nanomedicine, and nano-enabled consumer products is an ever-expanding discipline as is the concern over the impact of nanotechnology on human environmental health and safety. In this review, we discuss the current state of understanding of nanomaterial skin interactions with a specific emphasis on the effects of ultraviolet radiation (UVR) skin exposure. Skin is the largest organ of the body and is typically exposed to UVR on a daily basis. This necessitates the need to understand how UVR skin exposure can influence nanomaterial skin penetration, alter nanomaterial systemic trafficking, toxicity, and skin immune function. We explore the unique dichotomy that UVR has on inducing both deleterious and therapeutic effects in skin. The subject matter covered in this review is broadly informative and will raise awareness of potential increased risks from nanomaterial skin exposure associated with specific occupational and life style choices. The UVR-induced immunosuppressive response in skin raises intriguing questions that motivate future research directions in the nanotoxicology and nanomedicine fields. © 2013 Wiley Periodicals, Inc.

  3. Adverse and beneficial effects of plant extracts on skin and skin disorders.

    Science.gov (United States)

    Mantle, D; Gok, M A; Lennard, T W

    2001-06-01

    Plants are of relevance to dermatology for both their adverse and beneficial effects on skin and skin disorders respectively. Virtually all cultures worldwide have relied historically, or continue to rely on medicinal plants for primary health care. Approximately one-third of all traditional medicines are for treatment of wounds or skin disorders, compared to only 1-3% of modern drugs. The use of such medicinal plant extracts for the treatment of skin disorders arguably has been based largely on historical/anecdotal evidence, since there has been relatively little data available in the scientific literature, particularly with regard to the efficacy of plant extracts in controlled clinical trials. In this article therefore, adverse and beneficial aspects of medicinal plants relating to skin and skin disorders have been reviewed, based on recently available information from the peer-reviewed scientific literature. Beneficial aspects of medicinal plants on skin include: healing of wounds and burn injuries (especially Aloe vera); antifungal, antiviral, antibacterial and acaricidal activity against skin infections such as acne, herpes and scabies (especially tea tree (Melaleuca alternifolia) oil); activity against inflammatory/immune disorders affecting skin (e.g. psoriasis); and anti-tumour promoting activity against skin cancer (identified using chemically-induced two-stage carcinogenesis in mice). Adverse effects of plants on skin reviewed include: irritant contact dermatitis caused mechanically (spines, irritant hairs) or by irritant chemicals in plant sap (especially members of the Ranunculaceae, Euphorbiaceae and Compositae plant families); phytophotodermatitis resulting from skin contamination by plants containing furocoumarins, and subsequent exposure to UV light (notably members of the Umbelliferae and Rutaceae plant families); and immediate (type I) or delayed hypersensitivity contact reactions mediated by the immune system in individuals sensitized to plants

  4. The Nonlinear Talbot Effect of Rogue Waves

    CERN Document Server

    Zhang, Yiqi; Zheng, Huaibin; Chen, Haixia; Li, Changbiao; Song, Jianping; Zhang, Yanpeng

    2014-01-01

    Akhmediev and Kuznetsov-Ma breathers are rogue wave solutions of the nonlinear Schr\\"odinger equation (NLSE). Talbot effect (TE) is an image recurrence phenomenon in the diffraction of light waves. We report the nonlinear TE of rogue waves in a cubic medium. It is different from the linear TE, in that the wave propagates in a NL medium and is an eigenmode of NLSE. Periodic rogue waves impinging on a NL medium exhibit recurrent behavior, but only at the TE length and at the half-TE length with a \\pi-phase shift; the fractional TE is absent. The NL TE is the result of the NL interference of the lobes of rogue wave breathers. This interaction is related to the transverse period and intensity of breathers, in that the bigger the period and the higher the intensity, the shorter the TE length.

  5. Skin-lightening cosmetics: frequent, potentially severe adverse effects.

    Science.gov (United States)

    2011-09-01

    Skin-lightening cosmetics are used by many women and men around the world. The products contain a variety of substances, which are often unknown to the users. Most of these products include topical corticosteroids, hydroquinone and mercury salts. Many other substances may be added. Several surveys and cohort studies, including several thousand individuals, have shown that regular application of skin-lightening cosmetics to large surface areas can have irreversible cutaneous adverse effects, such as patchy hyper- or hypopigmentation, skin atrophy, stretch marks and delayed wound healing, and can also mask or, on the contrary, promote or reactivate skin infections. Cases of skin cancer have been attributed to skin-lightening cosmetics. A Senegalese cohort study of 147 women showed a statistically significant increase in the risk of hypertension and diabetes linked to the use of skin-lightening agents. Other systemic adverse effects attributed to skin-lightening cosmetics include Cushing's syndrome, adrenal insufficiency, nephrotic syndrome, neurological disorders, and ocular disorders. Hypersensitivity reactions, including anaphylaxis, have also been attributed to these products. Many skin-lightening cosmetics contain substances that can harm the unborn child. For example, tretinoin is teratogenic while salicylic acid is feto-toxic. In practice, users are often unaware of the risk of severe adverse effects associated with skin-lightening cosmetics. Users should be informed of these adverse effects and encouraged to stop using these products, especially when skin disorders appear.

  6. Nonlinear Radiation Effects on Hydromagnetic Boundary Layer Flow and Heat Transfer over a Shrinking Surface

    Directory of Open Access Journals (Sweden)

    anjali devi

    2015-01-01

    Full Text Available The effects of nonlinear radiation on hydromagnetic boundary layer flow and heat transfer over a shrinking surface is investigated in the present work. Using suitable similarity transformations, the governing nonlinear partial differential equations are transformed into nonlinear ordinary differential equations. The resultant equations which are highly nonlinear are solved numerically using Nachtsheim Swigert shooting iteration scheme together with Fourth Order Runge Kutta method. Numerical solutions for velocity, skin friction coefficient and temperature are obtained for various values of physical parameters involved in the study namely Suction parameter, Magnetic parameter, Prandtl number, Radiation parameter and Temperature ratio parameter. Numerical values for dimensionless rate of heat transfer are also obtained for various physical parameters and are shown through tables. The analytical solution of the energy equation when the radiation term is taken in linear form is obtained using Confluent hypergeometric function.

  7. The Geometric Nonlinear Generalized Brazier Effect

    DEFF Research Database (Denmark)

    Nikolajsen, Jan Ánike; Lauridsen, Peter Riddersholm; Damkilde, Lars

    2016-01-01

    denoted the generalized Brazier effect. The original work of Brazier dealt with very large deformations that changed the cross section significantly and hereby also the bending moment of inertia and the bending moment capacity. In this paper the aim is to describe the Brazier effect for smaller...... that the generalized Brazier effect is a local effect not influencing the overall mechanical behavior of the structure significantly. The offset is a nonlinear geometric beam-type Finite Element calculation, which takes into account the large displacements and rotations. The beam-type model defines the stresses which...... deformation not taking into account the change in moment of inertia. However, the generalized Brazier effect gives additional stresses directed perpendicular to the beam axis. In composite structures these extra stresses may influence the fatigue life significantly. The paper demonstrates a linearized method...

  8. Enhanced Kerr electro-optic nonlinearity through cascaded Pockels effects

    CERN Document Server

    Li, Guang-Zhen; Jiang, Hao-Wei; Chen, Xian-Feng

    2015-01-01

    We demonstrated a large enhancement of Kerr electro-optic nonlinearity through cascaded Pockels effects in a domain inversion ferroelectric crystal. We designed a structure that can implement the cascaded Pockels effects and second-harmonic generation simultaneously. The energy coupling between the fundamental lights of different polarizations led to a large nonlinear phase shift, and thus an effective electro-optic nonlinear refractive index. The effective nonlinearity can be either positive or negative, causing the second-harmonic spectra to move towards the coupling center, which in turn, offered us a way to measure the effective electro-optic nonlinear refractive index. The corresponding enhanced Kerr electro-optic nonlinearity is more than three orders of magnitude higher than the intrinsic value. These results open a door to manipulate the nonlinear phase by applying external electric field instead of light intensity in noncentrosymmetric crystals.

  9. Analysis on the effect of nonlinear polarization evolution in nonlinear amplifying loop mirror

    Institute of Scientific and Technical Information of China (English)

    Feng Qu; Xiaoming Liu; Pu Zhang; Xubiao Jiang; Hongming Zhang; Minyu Yao

    2005-01-01

    By considering the cross phase modulation (XPM) between the two orthogonal poparization components,the nonlinear birefringence and nonlinear polarization evolution (NPE) in highly-nonlinear fiber (HNLF),as well as the unequal evolutions of the state of polarization (SOP) between the clockwise (CW) and counter-clockwise (CCW) waves in a nonlinear amplifying loop mirror (NALM) are analyzed. It is pointed out that the traditional cosine expression is no longer valid for the power transmission of NALM due to uncompleted interference under the high power condition. The analytical expression considering NPE effect is derived, and the experimental result is presented.

  10. Development and validation of a tokamak skin effect transformer model

    Science.gov (United States)

    Romero, J. A.; Moret, J.-M.; Coda, S.; Felici, F.; Garrido, I.

    2012-02-01

    A lumped parameter, state space model for a tokamak transformer including the slow flux penetration in the plasma (skin effect transformer model) is presented. The model does not require detailed or explicit information about plasma profiles or geometry. Instead, this information is lumped in system variables, parameters and inputs. The model has an exact mathematical structure built from energy and flux conservation theorems, predicting the evolution and non-linear interaction of plasma current and internal inductance as functions of the primary coil currents, plasma resistance, non-inductive current drive and the loop voltage at a specific location inside the plasma (equilibrium loop voltage). Loop voltage profile in the plasma is substituted by a three-point discretization, and ordinary differential equations are used to predict the equilibrium loop voltage as a function of the boundary and resistive loop voltages. This provides a model for equilibrium loop voltage evolution, which is reminiscent of the skin effect. The order and parameters of this differential equation are determined empirically using system identification techniques. Fast plasma current modulation experiments with random binary signals have been conducted in the TCV tokamak to generate the required data for the analysis. Plasma current was modulated under ohmic conditions between 200 and 300 kA with 30 ms rise time, several times faster than its time constant L/R ≈ 200 ms. A second-order linear differential equation for equilibrium loop voltage is sufficient to describe the plasma current and internal inductance modulation with 70% and 38% fit parameters, respectively. The model explains the most salient features of the plasma current transients, such as the inverse correlation between plasma current ramp rates and internal inductance changes, without requiring detailed or explicit information about resistivity profiles. This proves that a lumped parameter modelling approach can be used to

  11. Ecology: Nonlinearity and the Moran effect

    Science.gov (United States)

    Blasius, Bernd; Stone, Lewi

    2000-08-01

    The study of synchronization phenomena in ecology is important because it helps to explain interactions between population dynamics and extrinsic environmental variation. Grenfell et al. have examined synchronized fluctuations in the sizes of two populations of feral sheep which, although situated on close but isolated islands, were nevertheless strongly correlated (observed value of the population correlation, rp, 0.685). Using a nonlinear threshold model, they argue that this level of population correlation could only be explained if environmental stochasticity was correlated between the islands, with the environmental correlation, re, higher than 0.9 ``on average'' (Fig. 1a). This unusually high environmental correlation is far greater than would be predicted by the Moran effect, which states that the population correlation will equal the environmental correlation in a linear system. Grenfell et al. imply that a simple nonlinearity in population growth can mask or even destroy the Moran effect. Here we show that these surprising results are an artefact of the techniques used to measure noise correlations and synchronization.

  12. Effects of a skin neuropeptide (substance p) on cutaneous microflora.

    Science.gov (United States)

    Mijouin, Lily; Hillion, Mélanie; Ramdani, Yasmina; Jaouen, Thomas; Duclairoir-Poc, Cécile; Follet-Gueye, Marie-Laure; Lati, Elian; Yvergnaux, Florent; Driouich, Azzedine; Lefeuvre, Luc; Farmer, Christine; Misery, Laurent; Feuilloley, Marc G J

    2013-01-01

    Skin is the largest human neuroendocrine organ and hosts the second most numerous microbial population but the interaction of skin neuropeptides with the microflora has never been investigated. We studied the effect of Substance P (SP), a peptide released by nerve endings in the skin on bacterial virulence. Bacillus cereus, a member of the skin transient microflora, was used as a model. Exposure to SP strongly stimulated the cytotoxicity of B. cereus (+553±3% with SP 10(-6) M) and this effect was rapid (microbiote should be another mechanism.

  13. Modal Identification Using OMA Techniques: Nonlinearity Effect

    Directory of Open Access Journals (Sweden)

    E. Zhang

    2015-01-01

    Full Text Available This paper is focused on an assessment of the state of the art of operational modal analysis (OMA methodologies in estimating modal parameters from output responses of nonlinear structures. By means of the Volterra series, the nonlinear structure excited by random excitation is modeled as best linear approximation plus a term representing nonlinear distortions. As the nonlinear distortions are of stochastic nature and thus indistinguishable from the measurement noise, a protocol based on the use of the random phase multisine is proposed to reveal the accuracy and robustness of the linear OMA technique in the presence of the system nonlinearity. Several frequency- and time-domain based OMA techniques are examined for the modal identification of simulated and real nonlinear mechanical systems. Theoretical analyses are also provided to understand how the system nonlinearity degrades the performance of the OMA algorithms.

  14. Nonvolatile Memory Based on Nonlinear Magnetoelectric Effects

    Science.gov (United States)

    Shen, Jianxin; Cong, Junzhuang; Chai, Yisheng; Shang, Dashan; Shen, Shipeng; Zhai, Kun; Tian, Ying; Sun, Young

    2016-08-01

    The magnetoelectric effects in multiferroics have a great potential in creating next-generation memory devices. We use an alternative concept of nonvolatile memory based, on a type of nonlinear magnetoelectric effects showing a butterfly-shaped hysteresis loop. The principle is to utilize the states of the magnetoelectric coefficient, instead of magnetization, electric polarization, or resistance, to store binary information. Our experiments in a device made of the PMN-PT/Terfenol-D multiferroic heterostructure clearly demonstrate that the sign of the magnetoelectric coefficient can be repeatedly switched between positive and negative by applying electric fields, confirming the feasibility of this principle. This kind of nonvolatile memory has outstanding practical virtues such as simple structure, easy operation in writing and reading, low power, fast speed, and diverse materials available.

  15. Linear- and nonlinear-electromyographic analysis of supracutaneous vibration stimuli of the forearm using diverse frequencies and considering skin physiological properties.

    Science.gov (United States)

    Ko, Chang-Yong; Chang, Yunhee; Kim, Sol-Bi; Kim, Shinki; Kim, Gyoosuk; Ryu, Jeicheong; Mun, Musung

    2014-01-01

    Numerous studies have reported the efficacy of vibration in sensory feedback or substitution devices for users of myoelectric hand prostheses. Although most myoelectric hand prostheses are presently manipulated by a surface electromyogram (sEMG), only a few studies have been conducted on the effect of vibration on an sEMG. This study aimed to determine whether vibration stimulation affects the linear and nonlinear properties of surface electromyography (sEMG) considering the skin properties. The vibration stimuli, with frequencies ranging from 37 to 258 Hz, were applied to the proximal part of the arms of the eight female and seven male subjects. The skinfold thickness, hardness, and vibration threshold at the stimuli loci were measured. The root mean square (rms) and fractal dimension (DF) of the sEMG were measured at a distance of 1 cm in the upward direction from the stimuli loci. Above 223 Hz there were no differences between the rms of the genders in between the vibration stimuli (p > 0.05). Moreover, no differences were observed between the DF of the genders for any frequency (p > 0.05). Above 149 Hz, there were correlations between the rms and the skin hardness in the females. Otherwise, no correlations were observed between the rms and DF and the skin properties in both genders for most of the frequencies (all p > 0.05). These results suggest that vibration stimuli affect the linear properties of the sEMG, but not the nonlinear properties.

  16. The framing effect and skin conductance responses

    Directory of Open Access Journals (Sweden)

    Patrick eRing

    2015-08-01

    Full Text Available Individuals often rely on simple heuristics when they face complex choice situations under uncertainty. Traditionally, it has been proposed that cognitive processes are the main driver to evaluate different choice options and finally to reach a decision. Growing evidence, however, highlights a strong interrelation between judgment and decision-making (JDM on the one hand, and emotional processes on the other hand. This also seems to apply to judgmental heuristics, i.e. decision-processes that are typically considered to be fast and intuitive. In this study, participants are exposed to different probabilities of receiving an unpleasant electric shock. Information about electric shock probabilities is either positively or negatively framed. Integrated skin conductance responses (ISCRs while waiting for electric shock realization are used as an indicator for participants' emotional arousal. This measure is compared to objective probabilities. I find evidence for a relation between emotional body reactions measured by ISCRs and the framing effect. Under negative frames, participants show significantly higher ISCRs while waiting for an electric shock to be delivered than under positive frames. This result might contribute to a better understanding of the psychological processes underlying JDM. Further studies are necessary to reveal the causality underlying this finding, i.e. whether emotional processes influence JDM or vice versa.

  17. The framing effect and skin conductance responses.

    Science.gov (United States)

    Ring, Patrick

    2015-01-01

    Individuals often rely on simple heuristics when they face complex choice situations under uncertainty. Traditionally, it has been proposed that cognitive processes are the main driver to evaluate different choice options and to finally reach a decision. Growing evidence, however, highlights a strong interrelation between judgment and decision-making (JDM) on the one hand, and emotional processes on the other hand. This also seems to apply to judgmental heuristics, i.e., decision processes that are typically considered to be fast and intuitive. In this study, participants are exposed to different probabilities of receiving an unpleasant electric shock. Information about electric shock probabilities is either positively or negatively framed. Integrated skin conductance responses (ISCRs) while waiting for electric shock realization are used as an indicator for participants' emotional arousal. This measure is compared to objective probabilities. I find evidence for a relation between emotional body reactions measured by ISCRs and the framing effect. Under negative frames, participants show significantly higher ISCRs while waiting for an electric shock to be delivered than under positive frames. This result might contribute to a better understanding of the psychological processes underlying JDM. Further studies are necessary to reveal the causality underlying this finding, i.e., whether emotional processes influence JDM or vice versa.

  18. Effects of repeated skin exposure to low nickel concentrations

    DEFF Research Database (Denmark)

    Nielsen, N H; Menné, T; Kristiansen, J

    1999-01-01

    and nickel allergy, either on normal or on SLS-treated forearm skin. The present study strongly suggests that the changes observed were specific to nickel exposure. Standardized methods to assess trace to moderate nickel exposure on the hands, and the associated effects in nickel-sensitized subjects...... with a group of patients who immersed a finger into water. The nickel concentrations used also provoked significant inflammatory skin changes on sodium lauryl sulphate (SLS)-treated forearm skin of the patients, whereas inflammatory skin changes were not observed in healthy volunteers without hand eczema...

  19. FALLOUT RADIATION: EFFECTS ON THE SKIN

    Energy Technology Data Exchange (ETDEWEB)

    Conard, R. A.; Cronkite, E. P.; Bond, V. P.

    1963-02-06

    Until recently it has been generally assumed that injury to the skin from ionizing radiation was not a serious hazard associated with the detonation of nuclear dcvices. However, in 1954 the importance of this hazard became apparent when widespread lesions of the skin developed in a large group of people accidentally exposed to fallout radiation in the Marshall Islands following the experimental detonation of a large nuclear device. The accident in the Marshall Islands affords an example of large numbers of lesions of the skin in human beings from the fallout. Studies have been documented and will be referred to frequently in this chapter. The possibility of such accidents must be considered seriously in view of the increasingly widespread use of radioisotopes.

  20. CONVECTIVE DRYING OF CHERRY TOMATO: STUDY OF SKIN EFFECT

    Directory of Open Access Journals (Sweden)

    R. KHAMA

    2016-03-01

    Full Text Available A whole single cherry tomato was dried in a forced convective micro-dryer. The experiments were carried out at constant air velocity and humidity and temperatures of 50, 60, 70 °C. In order to study the effect of the skin, two sets of experiments were performed using a tomato with and without skin (easily removed. Shorter drying times were obtained when increasing drying temperatures as well as when removing sample skin. X-ray microtomography, a non-destructive 3D imaging technique was used to follow shrinkage of the samples. This phenomenon was introduced in the modelling part of this study. Analytical solutions of the Fick’law were used to determine the diffusion coefficient at the three temperatures studied, and then the activation energy was obtained through fitting the Arrhenius equation. The skin effect was clearly evidenced by showing that the mass transfer parameter values of an original tomato with skin were largely smaller than the one without skin. Indeed, the moisture effective diffusivity ranged from 2.56×10-11 to 7.67×10-11 m2·s-1 with activation energy of 50430 J·mol-1 for tomato with skin an ranged from 4.59×10-10 m2·s-1 to 6.73×10-10 m2·s-1 with activation energy of 17640 J.mol-1 for tomato without skin.

  1. Calendula extract: effects on mechanical parameters of human skin.

    Science.gov (United States)

    Akhtar, Naveed; Zaman, Shahiq Uz; Khan, Barkat Ali; Amir, Muhammad Naeem; Ebrahimzadeh, Muhammad Ali

    2011-01-01

    The aim of this study was to evaluate the effects of newly formulated topical cream of Calendula officinalis extract on the mechanical parameters of the skin by using the cutometer. The Cutometer 580 MPA is a device that is designed to measure the mechanical properties of the skin in response to the application of negative pressure. This non-invasive method can be useful for objective and quantitative investigation of age related changes in skin, skin elasticity, skin fatigue, skin hydration, and evaluation of the effects of cosmetic and antiaging topical products. Two creams (base and formulation) were prepared for the study. Both the creams were applied to the cheeks of 21 healthy human volunteers for a period of eight weeks. Every individual was asked to come on week 1, 2, 3, 4, 5, 6, 7, and 8 and measurements were taken by using Cutometer MPA 580 every week. Different mechanical parameters of the skin measured by the cutometer were; R0, R1, R2, R5, R6, R7, and R8. These were then evaluated statistically to measure the effects produced by these creams. Using ANOVA, and t-test it was found that R0, and R6 were significant (p 0.05). The instrumental measurements produced by formulation reflected significant improvements in hydration and firmness of skin.

  2. Vibrational mechanics nonlinear dynamic effects, general approach, applications

    CERN Document Server

    Blekhman, Iliya I

    2000-01-01

    This important book deals with vibrational mechanics - the new, intensively developing section of nonlinear dynamics and the theory of nonlinear oscillations. It offers a general approach to the study of the effect of vibration on nonlinear mechanical systems.The book presents the mathematical apparatus of vibrational mechanics which is used to describe such nonlinear effects as the disappearance and appearance under vibration of stable positions of equilibrium and motions (i.e. attractors), the change of the rheological properties of the media, self-synchronization, self-balancing, the vibrat

  3. Analytical evaluation of nonlinear distortion effects on multicarrier signals

    CERN Document Server

    Araújo, Theresa

    2015-01-01

    Due to their ability to support reliable high quality of service as well as spectral and power efficiency, multicarrier modulation systems have found increasing use in modern communications services. However, one of the main drawbacks of these systems is their vulnerability to nonlinear distortion effects. Analytical Evaluation of Nonlinear Distortion Effects on Multicarrier Signals details a unified approach to well-known analytical results on memoryless nonlinearities that takes advantage of the Gaussian behavior of multicarrier signals.Sharing new insights into the behavior of nonlinearly d

  4. Effect of glove occlusion on the skin barrier

    DEFF Research Database (Denmark)

    Tiedemann, Daniel; Clausen, Maja Lisa; John, Swen Malthe

    2016-01-01

    that the negative effect of occlusion in itself is limited, and that only extensive and long-term occlusion will cause barrier impairment. However, studies investigating combined effect of occlusion and exposure to soaps/detergents indicate that occlusion significantly enhances the skin barrier damage caused...... of this study is to review the literature on the effects of glove occlusion on skin barrier function. The PubMed database was searched up to 1 February 2015 for articles on the association between glove occlusion and skin barrier function, including human studies only and in English. Only experimental studies...... by detergents/soaps in a dose-response fashion....

  5. Effect of neutron skin thickness on projectile fragmentation

    CERN Document Server

    Dai, Z T; Ma, Y G; Cao, X G; Zhang, G Q; Shen, W Q

    2015-01-01

    The fragment production in collisions of $^{48,50}$Ca+$^{12}$C at 50 MeV/nucleon are simulated via the Isospin-Dependent Quantum Molecular Dynamics (IQMD) model followed by the {GEMINI code}. {By changing the diffuseness parameter of neutron density distribution to obtain different neutron skin size, the effects of neutron skin thickness (${\\delta}_{np}$) on projectile-like fragments (PLF) are investigated. The sensitivity of isoscaling behavior to neutron skin size is studied, from which it is found that the isoscaling parameter $\\alpha$ has a linear dependence on ${\\delta}_{np}$. A linear dependence between ${\\delta}_{np}$ and the mean $N/Z$ [N(Z) is neutron(proton) number] of PLF is obtained as well.} The results show that thicker neutron skin will lead to smaller {isoscaling parameter} $\\alpha$ and N/Z. Therefore, it may be probable to extract information of neutron skin thickness from {isoscaling parameter} $\\alpha$ and N/Z.

  6. Effect of Systemic Antioxidant Allopurinol Therapy on Skin Flap Survival

    Science.gov (United States)

    Rasti Ardakani, Mehdi; Al-Dam, Ahmed; Rashad, Ashkan; Shayesteh Moghadam, Ali

    2017-01-01

    BACKGROUND It has been reported that systemic administration of allopurinol improves cell survival. This study was aimed to evaluate effects of allopurinol on skin flaps in dogs. METHODS Twenty dogs underwent one skin flap surgery with a 2-week interval. The first procedure was performed according to the standard protocols. The second phase was started by a 1-week pretreatment with allopurinol. Length of the necrotic zone was measured and recorded daily. At each phase, flaps were removed and sent for histopathological study after 1 week observation. RESULTS Mean length of the necrotic zone in allopurinol treated skin flaps has been significantly less than normal flaps over all 7 days of observation (p<0.0001). Histopathology study showed less inflammation and more normal tissue structure in the allopurinol treated skin flaps. CONCLUSION It was demonstrated that systemic administration of allopurinol significantly improved skin flap survival. PMID:28289614

  7. A Novel Effective Approach for Solving Fractional Nonlinear PDEs.

    Science.gov (United States)

    Aminikhah, Hossein; Malekzadeh, Nasrin; Rezazadeh, Hadi

    2014-01-01

    The present work introduces an effective modification of homotopy perturbation method for the solution of nonlinear time-fractional biological population model and a system of three nonlinear time-fractional partial differential equations. In this approach, the solution is considered a series expansion that converges to the nonlinear problem. The new approximate analytical procedure depends only on two iteratives. The analytical approximations to the solution are reliable and confirm the ability of the new homotopy perturbation method as an easy device for computing the solution of nonlinear equations.

  8. Effects of Essential Oils and Polyunsaturated Fatty Acids on Canine Skin Equivalents: Skin Lipid Assessment and Morphological Evaluation

    OpenAIRE

    Cerrato, S.; Ramió-Lluch, L.; Fondevila, D.; Rodes, D.; P. Brazis; Puigdemont, A.

    2013-01-01

    A canine skin equivalent model has been validated for the assessment of a topical formulation effects. Skin equivalents were developed from freshly isolated cutaneous canine fibroblasts and keratinocytes, after enzymatic digestion of skin samples (n = 8) from different breeds. Fibroblasts were embedded into a collagen type I matrix, and keratinocytes were seeded onto its surface at air-liquid interface. Skin equivalents were supplemented with essential oils and polyunsaturated fatty acid form...

  9. Solid-armature railguns without the velocity-skin effect

    Energy Technology Data Exchange (ETDEWEB)

    Cowan, M.

    1991-12-31

    If the velocity-skin effect could be eliminated, solid-armature railguns might reach high velocity ({ge} 6 km/s) without forcing most of the armature current to pass through an arc. Even then, magnetic diffusion (the ``normal`` skin effect) will limit acceleration. In this paper, the performance limits for railguns which are free from the velocity-skin effect are investigated by deriving the upper limits for a specific kind of power supply. Previous performance estimates made for solid-armature railguns are examined in the light of these results and are found to be relatively very optimistic. A railgun design which limits the velocity-skin effect and which may allow improved performance for solid armatures is described. 6 refs.

  10. Effects of Neutron Skin Thickness in Peripheral Nuclear Reactions

    Institute of Scientific and Technical Information of China (English)

    FANG De-Qing; MA Yu-Gang; CAI Xiang-Zhou; TIAN Wen-Dong; WANG Hong-Wei

    2011-01-01

    Effects of neutron skin thickness in peripheral nuclear collisions are investigated using the statistical abrasion ablation (SAA) model. The reaction cross section, neutron (proton) removal cross section, one-neutron (proton) removal cross section as well as their ratios for nuclei with different neutron skin thickness are studied. It is demonstrated that there are good linear correlations between these observables and the neutron skin thickness for neutron-rich nuclei. The ratio between the (one-)neutron and proton removal cross section is found to be the most sensitive observable of neutron skin thickness. Analysis shows that the relative increase of this ratio could be used to determine the neutron skin size in neutron-rich nuclei.%Effects of neutron skin thickness in peripheral nuclear collisions are investigated using the statistical abrasion ablation (SAA ) model.The reaction cross section,neutron (proton) removal cross section,one-neutron (proton) removal cross section as well as their ratios for nuclei with different neutron skin thickness are studied.It is demonstrated that there are good linear correlations between these observables and the neutron skin thickness for neutron-rich nuclei.The ratio between the (one-)neutron and proton removal cross section is found to be the most sensitive observable of neutron skin thickness.Analysis shows that the relative increase of this ratio could be used to determine the neutron skin size in neutron-rich nuclei.Determining the size and shape of a nucleus is one of the most important subjects since the discovery of atomic nuclei.The rms radii of the neutron (rn) and proton (rp) density distributions are among the most prominent observables for this purpose.Studies for stable nuclei have shown that the nuclear radii are proportional to A1/3,with A being the nuclear mass number.Meanwhile,the density distributions of neutrons and protons in stable nuclei are very similar.

  11. Effects of Particle Shape and Microstructure on Effective Nonlinear Response

    Institute of Scientific and Technical Information of China (English)

    HUANG Ji-Ping; LI Zhen-Ya

    2001-01-01

    We consider a binary granular composite medium, in which two materials have high-order nonlinearities.The effect of particle shape on effective nonlinear response (ENR) is investigated by assuming all the particles to be shaped as uniaxial ellipsoid. We discuss two types of arrangements of particles: 1) parallel axes (Case I); 2) random axes (Case II). During the process of numerical calculation, one component material is assumed to be linear, and two kinds of conductors are assumed to be at high conducting contrast. We find that: 1) the shape effect on ENR is possibly strong; 2) the enhanced ENR can even be obtained by choosing particles of appropriate ellipsoidal shapes; 3) the ENR enhancement predicted by Case I is much stronger than that by Case II.``

  12. Electron scattering and nonlinear trapping by oblique whistler waves: The critical wave intensity for nonlinear effects

    Energy Technology Data Exchange (ETDEWEB)

    Artemyev, A. V., E-mail: ante0226@gmail.com; Vasiliev, A. A. [Space Research Institute, RAS, Moscow (Russian Federation); Mourenas, D.; Krasnoselskikh, V. V. [LPC2E/CNRS—University of Orleans, Orleans (France); Agapitov, O. V. [Space Sciences Laboratory, University of California, Berkeley, California 94720 (United States)

    2014-10-15

    In this paper, we consider high-energy electron scattering and nonlinear trapping by oblique whistler waves via the Landau resonance. We use recent spacecraft observations in the radiation belts to construct the whistler wave model. The main purpose of the paper is to provide an estimate of the critical wave amplitude for which the nonlinear wave-particle resonant interaction becomes more important than particle scattering. To this aim, we derive an analytical expression describing the particle scattering by large amplitude whistler waves and compare the corresponding effect with the nonlinear particle acceleration due to trapping. The latter is much more rare but the corresponding change of energy is substantially larger than energy jumps due to scattering. We show that for reasonable wave amplitudes ∼10–100 mV/m of strong whistlers, the nonlinear effects are more important than the linear and nonlinear scattering for electrons with energies ∼10–50 keV. We test the dependencies of the critical wave amplitude on system parameters (background plasma density, wave frequency, etc.). We discuss the role of obtained results for the theoretical description of the nonlinear wave amplification in radiation belts.

  13. Topological nature of nonlinear optical effects in solids.

    Science.gov (United States)

    Morimoto, Takahiro; Nagaosa, Naoto

    2016-05-01

    There are a variety of nonlinear optical effects including higher harmonic generations, photovoltaic effects, and nonlinear Kerr rotations. They are realized by strong light irradiation to materials that results in nonlinear polarizations in the electric field. These are of great importance in studying the physics of excited states of the system as well as for applications to optical devices and solar cells. Nonlinear properties of materials are usually described by nonlinear susceptibilities, which have complex expressions including many matrix elements and energy denominators. On the other hand, a nonequilibrium steady state under an electric field periodic in time has a concise description in terms of the Floquet bands of electrons dressed by photons. We show theoretically, using the Floquet formalism, that various nonlinear optical effects, such as the shift current in noncentrosymmetric materials, photovoltaic Hall response, and photo-induced change of order parameters under the continuous irradiation of monochromatic light, can be described in a unified fashion by topological quantities involving the Berry connection and Berry curvature. We found that vector fields defined with the Berry connections in the space of momentum and/or parameters govern the nonlinear responses. This topological view offers a route to designing nonlinear optical materials.

  14. Higher-order nonlinear effects in a Josephson parametric amplifier

    Science.gov (United States)

    Kochetov, Bogdan A.; Fedorov, Arkady

    2015-12-01

    Nonlinearity of the current-phase relationship of a Josephson junction is the key resource for a Josephson parametric amplifier (JPA) as well as for a Josephson traveling-wave parametric amplifier, the only devices in which the quantum limit for added noise has so far been approached at microwave frequencies. A standard approach to describe JPA takes into account only the lowest order (cubic) nonlinearity resulting in a Duffing-like oscillator equation of motion or in a Kerr-type nonlinearity term in the Hamiltonian. In this paper we derive the quantum expression for the gain of JPA including all orders of the Josephson junction nonlinearity in the linear response regime. We then analyze gain saturation effect for stronger signals within a semiclassical approach. Our results reveal nonlinear effects of higher orders and their implications for operation of a JPA.

  15. Conservation Laws in Higher-Order Nonlinear Optical Effects

    CERN Document Server

    Kim, J; Shin, H J; Kim, Jongbae

    1999-01-01

    Conservation laws of the nonlinear Schrödinger equation are studied in the presence of higher-order nonlinear optical effects including the third-order dispersion and the self-steepening. In a context of group theory, we derive a general expression for infinitely many conserved currents and charges of the coupled higher-order nonlinear Schrödinger equation. The first few currents and charges are also presented explicitly. Due to the higher-order effects, conservation laws of the nonlinear Schrödinger equation are violated in general. The differences between the types of the conserved currents for the Hirota and the Sasa-Satsuma equations imply that the higher-order terms determine the inherent types of conserved quantities for each integrable cases of the higher-order nonlinear Schrödinger equation.

  16. UV doses and skin effects during psoriasis climate therapy

    Science.gov (United States)

    Randeberg, Lise L.; Hernandez-Palacios, Julio; Lilleeng, Mila; Nilsen, Lill Tove; Krogstad, Anne-Lene

    2011-03-01

    Psoriasis is a common autoimmune disease with inflammatory symptoms affecting skin and joints. One way of dealing with psoriasis is by controlled solar UV exposure treatment. However, this treatment should be optimized to get the best possible treatment effect and to limit negative side effects such as erythema and an increased risk of skin cancer. In this study 24 patients at Valle Marina Treatment Center in Gran Canaria were monitored throughout a treatment period of three weeks starting at the beginning of November. The total UV dose to the location was monitored by UV-meters placed on the roof of the treatment centere, and the patients wore individual film dosimeters throughout the treatment period. Skin parameters were accessed by reflection spectroscopy (400-850nm). This paper presents preliminary findings from the skin measurements in the visible part of the spectrum, such as blood oxygenation, erythema and melanin indexes. Reflection spectroscopy was found to be a good tool for such treatment monitoring.

  17. Nonlinear Mixed-Effects Models for Repairable Systems Reliability

    Institute of Scientific and Technical Information of China (English)

    TAN Fu-rong; JIANG Zhi-bin; KUO Way; Suk Joo BAE

    2007-01-01

    Mixed-effects models, also called random-effects models, are a regression type of analysis which enables the analyst to not only describe the trend over time within each subject, but also to describe the variation among different subjects. Nonlinear mixed-effects models provide a powerful and flexible tool for handling the unbalanced count data. In this paper, nonlinear mixed-effects models are used to analyze the failure data from a repairable system with multiple copies. By using this type of models, statistical inferences about the population and all copies can be made when accounting for copy-to-copy variance. Results of fitting nonlinear mixed-effects models to nine failure-data sets show that the nonlinear mixed-effects models provide a useful tool for analyzing the failure data from multi-copy repairable systems.

  18. Effect of gain nonlinearity in semiconductor lasers

    DEFF Research Database (Denmark)

    Jensen, Niels H.; Christiansen, Peter Leth; Skovgaard, Ove

    1988-01-01

    Semiconductor lasers are modeled by single-mode rate equations with Langevin noise terms and the influence of nonlinear gain is investigated. For cw operation the probability distribution for the carrier number and the photon number in the laser cavity is obtained. The corresponding (2......+1)-dimensional Fokker-Planck equation is derived and integrated on an Amdahl VP1100 vector processor. Above threshold the resulting probability density agrees with the rate-equation predictions. The case of high-speed modulation is also considered. The nonlinear gain is found to stabilize the laser....

  19. Microplasma effect on skin scaffold for melanoma cancer treatment

    Science.gov (United States)

    Abdullah, Zulaika; Zaaba, S. K.; Mustaffa, M. T.; Mohamad, C. W. S. R.; Zakaria, A.

    2017-03-01

    An atmospheric plasma system using Helium gas was developed. The effect of helium plasma treatment on skin scaffold surface was studied by scanning electron microscopy (SEM). The changes of skin scaffold surfaces before and after helium plasma treatment was recorded. The surface of skin scaffold changed with the prolonged of helium plasma treatment time. The depth of helium plasma penetration was studied using methylene blue dye staining method. The methylene blue will detect the presence or absence of an oxygen that was induced from plasma excitation. The presence of the oxygen indicated on the depth of helium plasma penetration. Results showed plasma are able to penetrate 4mm of skin scaffold after 1200 seconds of exposure.

  20. Moisturizing effects of topical nicotinamide on atopic dry skin.

    Science.gov (United States)

    Soma, Yoshinao; Kashima, Masato; Imaizumi, Akiko; Takahama, Hideto; Kawakami, Tamihiro; Mizoguchi, Masako

    2005-03-01

    Certain moisturizers can improve skin barrier function in atopic dermatitis. The effect of topical nicotinamide on atopic dry skin is unknown. We examined the effect of topical nicotinamide on atopic dry skin and compared the results with the effect of white petrolatum in a left-right comparison study. Twenty-eight patients with atopic dermatitis, with symmetrical lesions of dry skin on both forearms, were enrolled, and were instructed to apply nicotinamide cream containing 2% nicotinamide on the left forearm and white petrolatum on the right forearm, twice daily over a 4- or 8-week treatment period. Transepidermal water loss and stratum corneum hydration were measured by instrumental devices. The amount of the stratum corneum exfoliated by tape stripping (desquamation index) was determined by an image analyzer. Nicotinamide significantly decreased transepidermal water loss, but white petrolatum did not show any significant effect. Both nicotinamide and white petrolatum increased stratum corneum hydration, but nicotinamide was significantly more effective than white petrolatum. The desquamation index was positively correlated with stratum corneum hydration at baseline and gradually increased in the nicotinamide group, but not in the white petrolatum group. Nicotinamide cream is a more effective moisturizer than white petrolatum on atopic dry skin, and may be used as a treatment adjunct in atopic dermatitis.

  1. Intra-Channel Nonlinear Effect on Optical PPM Pulse Transmission

    Institute of Scientific and Technical Information of China (English)

    Sun; Linghao; Jarmo; Takala

    2003-01-01

    PPM encoded Gaussian pulse sequence shows more immunity than non-PPM schemes on optical fiber intra-channel nonlinearity and demonstrated by a numerical study of IXPM and IFWM effects deploying on 100Gb/s single channelsystem.

  2. Effects of Nonlinearities on Induced Voltages across Lumped Devices

    Directory of Open Access Journals (Sweden)

    Ziya Mazloom

    2011-01-01

    Full Text Available There have been many studies on induced currents and voltages along overhead conductors due to lightning flashes. In most of these studies lumped loads and components are connected only as line terminations [1]-[4]. In studies where series and shunt connected components are connected along the lines the effects of nonlinear components and effects are disregarded [5]-[8]. This is not always correct as nonlinear effects will introduce high frequencies in the system and affect the current and voltage wave distribution. In this paper the effects of series and shunt components and nonlinear phenomenon on a system representative of the Swedish electrified railway system will be investigated. It is seen how introduction of different linear and nonlinear components affect the propagating voltage wave forms.

  3. Experimental study of the nonlinear diffusion of a magnetic field and skin explosion of cylindrical conductors

    Energy Technology Data Exchange (ETDEWEB)

    Chaikovsky, S. A.; Datsko, I. M.; Labetskaya, N. A.; Rybka, D. V.; Ratakhin, N. A. [Institute of High Current Electronics, SB, RAN, Tomsk (Russian Federation); Oreshkin, V. I. [Institute of High Current Electronics, SB, RAN, Tomsk (Russian Federation); Tomsk Polytechnic University, Tomsk (Russian Federation)

    2015-11-15

    The paper presents the results of an experimental study of the skin explosion of cylindrical conductors of diameter 1–3 mm (copper, aluminum, titanium, steel 3, and stainless steel) at a peak magnetic field of 200–600 T. The experiments were carried out on the MIG pulsed power generator at a current of up to 2.5 MA and a current rise time of 100 ns. The surface explosion of a conductor was identified by the appearance of a flash of extreme ultraviolet radiation. A minimum magnetic induction has been determined below which no plasma is generated at the conductor surface. For copper, aluminum, steel 3, titanium, and stainless steel, the minimum magnetic induction has been estimated to be (to within 10%) 375, 270, 280, 220, and 245 T, respectively.

  4. Dissipation Effects on MHD Nonlinear Flow and Heat Transfer Past a Porous Surface with Prescribed Heat Flux

    Directory of Open Access Journals (Sweden)

    S.P. Anjali Devi

    2010-01-01

    Full Text Available Viscous and Joule dissipation effects are considered on MHD nonlinear flow and heat transfer past a stretching porous surface embedded in a porous medium under a transverse magnetic field. Analytical solutions of highly nonlinear momentum equation and confluent hypergeometric similarity solution of heat transfer equations in the case when the plate stretches with velocity varying linearly with distance are obtained. The effect of various parameters like suction parameter, Prandtl number, Magnetic parameter, and Eckert number entering into the velocity field, temperature distribution and skin friction co-efficient at the wall are discussed with the aid of graphs.

  5. Skin photoprotection by green tea: antioxidant and immunomodulatory effects.

    Science.gov (United States)

    Katiyar, Santosh K

    2003-09-01

    Because of a characteristic aroma and health benefits, green tea is consumed worldwide as a popular beverage. The epicatechin derivatives, commonly called polyphenols, present in green tea possess antioxidant, anti-inflammatory and anti-carcinogenic properties. The major and most highly chemopreventive constituent in green tea responsible for the biochemical or pharmacological effects is (-)-epigallocatechin-3-gallate (EGCG). Epidemiological, clinical and biological studies have implicated that solar ultraviolet (UV) light is a complete carcinogen and repeated exposure can lead to the development of various skin disorders including melanoma and nonmelanoma skin cancers. We and others have shown that topical treatment or oral consumption of green tea polyphenols (GTP) inhibit chemical carcinogen- or UV radiation-induced skin carcinogenesis in different laboratory animal models. Topical treatment of GTP and EGCG or oral consumption of GTP resulted in prevention of UVB-induced inflammatory responses, immunosuppression and oxidative stress, which are the biomarkers of several skin disease states. Topical application of GTP and EGCG prior to exposure of UVB protects against UVB-induced local as well as systemic immune suppression in laboratory animals, which was associated with the inhibition of UVB-induced infiltration of inflammatory leukocytes. Prevention of UVB-induced suppression of immune responses by EGCG was also associated with the reduction in immunosuppressive cytokine interleukin (IL)-10 production at UV irradiated skin and draining lymph nodes, whereas IL-12 production was significantly enhanced in draining lymph nodes. Antioxidant and anti-inflammatory effects of green tea were also observed in human skin. Treatment of EGCG to human skin resulted in the inhibition of UVB-induced erythema, oxidative stress and infiltration of inflammatory leukocytes. We also showed that treatment of GTP to human skin prevents UVB-induced cyclobutane pyrimidine dimers

  6. Effects of TLC-Ag dressings on skin inflammation.

    Science.gov (United States)

    Bisson, Jean-François; Hidalgo-Lucas, Sophie; Bouschbacher, Marielle; Thomassin, Laetitia

    2013-06-01

    The TLC-Ag dressings, a combination of technology lipido-colloid and silver salts, are used to promote healing in wounds with risks or signs of local infection, thanks to the antimicrobial properties of the silver salts. Nanocrystalline silver dressings containing nanocrystalline silver, also used to improve wound healing, present both antimicrobial and anti-inflammatory effects. The aim of this study was to investigate the anti-inflammatory effects of TLC-Ag dressings in a model of chronic skin inflammation induced by repeated application of 12-O-tetradecanoylphorbol-13-acetate to the skin of hairless mice, in comparison with TLC dressing, Silcryst nanocrystalline dressing, desonide cream 0.05%, a corticoid cream used as positive control, and gauze. Daily treatments of the mice began 7 days after the start of induction of chronic skin inflammation and lasted for 7 days. A macroscopic score was performed daily during the treatment period until the mice killing on day 15 and skin samples were taken for histopathological analysis. TLC-Ag reduced significantly the macroscopic score of chronic skin inflammation from day 10 in comparison with gauze and TLC dressing, similarly to Silcryst nanocrystalline dressing and desonide cream, which presented the best anti-inflammatory effects. No significant differences were observed between TLC dressing and gauze. TLC-Ag reduced significantly the microscopic score of chronic skin inflammation in comparison with TLC dressing and gauze, similarly to Silcryst nanocrystalline dressing but significantly less than desonide cream. These results demonstrate that TLC-Ag dressings present significant anti-inflammatory effects on chronic skin inflammation. They can improve wound healing, due to both the antimicrobial and anti-inflammatory properties. © 2013 Japanese Dermatological Association.

  7. Effects of a skin neuropeptide (substance p on cutaneous microflora.

    Directory of Open Access Journals (Sweden)

    Lily Mijouin

    Full Text Available BACKGROUND: Skin is the largest human neuroendocrine organ and hosts the second most numerous microbial population but the interaction of skin neuropeptides with the microflora has never been investigated. We studied the effect of Substance P (SP, a peptide released by nerve endings in the skin on bacterial virulence. METHODOLOGY/PRINCIPAL FINDINGS: Bacillus cereus, a member of the skin transient microflora, was used as a model. Exposure to SP strongly stimulated the cytotoxicity of B. cereus (+553±3% with SP 10(-6 M and this effect was rapid (<5 min. Infection of keratinocytes with SP treated B. cereus led to a rise in caspase1 and morphological alterations of the actin cytoskeleton. Secretome analysis revealed that SP stimulated the release of collagenase and superoxide dismutase. Moreover, we also noted a shift in the surface polarity of the bacteria linked to a peel-off of the S-layer and the release of S-layer proteins. Meanwhile, the biofilm formation activity of B. cereus was increased. The Thermo unstable ribosomal Elongation factor (Ef-Tu was identified as the SP binding site in B. cereus. Other Gram positive skin bacteria, namely Staphylococcus aureus and Staphylococcus epidermidis also reacted to SP by an increase of virulence. Thermal water from Uriage-les-Bains and an artificial polysaccharide (Teflose® were capable to antagonize the effect of SP on bacterial virulence. CONCLUSIONS/SIGNIFICANCE: SP is released in sweat during stress and is known to be involved in the pathogenesis of numerous skin diseases through neurogenic inflammation. Our study suggests that a direct effect of SP on the skin microbiote should be another mechanism.

  8. Radon exposure of the skin: I. Biological effects

    Energy Technology Data Exchange (ETDEWEB)

    Charles, M W [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2007-09-15

    Radon progeny can plate out on skin and give rise to exposure of the superficial epidermis from alpha emitters Po-218 (7.7 MeV, range {approx}66 {mu}m) and Po-214 (6 MeV, range {approx}44 {mu}m). Dose rates from beta/gamma emitters Pb-214 and Bi-214 are low and only predominate at depths in excess of the alpha range. This paper reviews the evidence for a causal link between exposure from radon and its progeny, and deterministic and stochastic biological effects in human skin. Radiation induced skin effects such as ulceration and dermal atrophy, which require irradiation of the dermis, are ruled out for alpha irradiation from radon progeny because the target cells are considerably deeper than the range of alpha particles. They have not been observed in man or animals. Effects such as erythema and acute epidermal necrosis have been observed in a few cases of very high dose alpha particle exposures in man and after acute high dose exposure in animals from low energy beta radiations with similar depth doses to radon progeny. The required skin surface absorbed doses are in excess of 100 Gy. Such effects would require extremely high levels of radon progeny. They would involve quite exceptional circumstances, way outside the normal range of radon exposures in man. There is no definitive identification of the target cells for skin cancer induction in animals or man. The stem cells in the basal layer which maintain the epidermis are the most plausible contenders for target cells. The majority of these cells are near the end of the range of radon progeny alpha particles, even on the thinnest body sites. The nominal depth of these cells, as recommended by the International Commission on Radiological Protection (ICRP), is 70 {mu}m. There is evidence however that some irradiation of the hair follicles and/or the deeper dermis, as well as the inter-follicular epidermis, is also necessary for skin cancer induction. Alpha irradiation of rodent skin that is restricted to the

  9. Effective nonlinear AC response to composite with spherical particles

    Institute of Scientific and Technical Information of China (English)

    Chen Xiao-Gang; Liang Fang-Chu; Wei En-Bo

    2005-01-01

    An effective nonlinear alternative-current (AC) response to granular nonlinear-composite with spherical inclusions embedded in a host medium under the action of an external AC field is investigated by using a perturbation approach.The local potentials of composite at higher harmonics are derived both in a region of local inclusion particles and in a local host region under the action of a sinusoidal field E1 sinωt + E3sin3ωt. An effective nonlinear-response to composite and the relationship between the effective nonlinear-responses at the fundamental frequency and the third harmonics are also studied for the spherical inclusions in a dilute limit.

  10. Non-linear effects in bunch compressor of TARLA

    Science.gov (United States)

    Yildiz, Hüseyin; Aksoy, Avni; Arikan, Pervin

    2016-03-01

    Transport of a beam through an accelerator beamline is affected by high order and non-linear effects such as space charge, coherent synchrotron radiation, wakefield, etc. These effects damage form of the beam, and they lead particle loss, emittance growth, bunch length variation, beam halo formation, etc. One of the known non-linear effects on low energy machine is space charge effect. In this study we focus on space charge effect for Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) machine which is designed to drive InfraRed Free Electron Laser covering the range of 3-250 µm. Moreover, we discuss second order effects on bunch compressor of TARLA.

  11. Fractional Identification of Rotor Skin Effect in Induction Machines

    Directory of Open Access Journals (Sweden)

    Jean-Claude Trigeassou

    2011-07-01

    Full Text Available Fractional identification of rotor skin effect in induction machines is presented in this paper. Park transformation is used to obtain a system of differential equations which allows to include the skin effect in the rotor bars of asynchronous machines. A transfer function with a fractional derivative order has been selected to represent the admittance of the bar by the help of a non integer integrator which is approximated by a J+1 dimensional modal system. The machine parameters are estimated by an output-error technique using a non linear iterative optimization algorithm. Numerical simulations and experimental results show the performance of the modal approach for modeling and identification.

  12. Computation of the effective nonlinear mechanical response of lattice materials considering geometrical nonlinearities

    Science.gov (United States)

    ElNady, Khaled; Goda, Ibrahim; Ganghoffer, Jean-François

    2016-09-01

    The asymptotic homogenization technique is presently developed in the framework of geometrical nonlinearities to derive the large strains effective elastic response of network materials viewed as repetitive beam networks. This works extends the small strains homogenization method developed with special emphasis on textile structures in Goda et al. (J Mech Phys Solids 61(12):2537-2565, 2013). A systematic methodology is established, allowing the prediction of the overall mechanical properties of these structures in the nonlinear regime, reflecting the influence of the geometrical and mechanical micro-parameters of the network structure on the overall response of the chosen equivalent continuum. Internal scale effects of the initially discrete structure are captured by the consideration of a micropolar effective continuum model. Applications to the large strain response of 3D hexagonal lattices and dry textiles exemplify the powerfulness of the proposed method. The effective mechanical responses obtained for different loadings are validated by FE simulations performed over a representative unit cell.

  13. The effect of pregnancy on paternal skin allograft survival

    Institute of Scientific and Technical Information of China (English)

    SHOU ZhangFei; XU YiFang; XIAO HuaYing; ZHOU Qin; CAI JieRu; YANG Yi; JIANG Hong; ZHANG WenJie; CHEN JiangHua

    2009-01-01

    Elucidation of maternal-fetal tolerance mechanisms clarifies the role of regulatory T cells (Treg)in transplant tolerance.This study aim to investigate the effect of pregnancy on paternal skin allograft survival.Flow cytometry techniques,mixed lymphocytes reaction (MLR),PCR,real-time PCR and skin transplantation were key methods.Treg increased significantly from 4.2% before pregnancy to peak at 6.8% day 8 after pregnancy.Both heme oxygenase-1 (HO-1)and indoleamine 2,3-dioxygenase (IDO)mRNA express high in placenta while low in spleen (P<0.05).Although Treg increased during pregnancy,and splenocytes from the pregnant mice showed lower MLR response toward the paternal stimulator,single time pregnancy showed no significant protective effect on paternal skin allograft survival in the tested condition.

  14. The effect of pregnancy on paternal skin allograft survival

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Elucidation of maternal-fetal tolerance mechanisms clarifies the role of regulatory T cells (Treg) in transplant tolerance. This study aim to investigate the effect of pregnancy on paternal skin allograft survival. Flow cytometry techniques, mixed lymphocytes reaction (MLR), PCR, real-time PCR and skin transplantation were key methods. Treg increased significantly from 4.2% before pregnancy to peak at 6.8% day 8 after pregnancy. Both heme oxygenase-1 (HO-1) and indoleamine 2,3-dioxygenase (IDO) mRNA express high in placenta while low in spleen (P<0.05). Although Treg increased during pregnancy, and splenocytes from the pregnant mice showed lower MLR response toward the paternal stimulator, single time pregnancy showed no significant protective effect on paternal skin allograft survival in the tested condition.

  15. The effect of grape-skin extract on oxidative status

    DEFF Research Database (Denmark)

    Young, J. F.; Dragsted, L. O.; Daneshvar, B.

    2000-01-01

    Epidemiological studies indicate that moderate alcohol consumption, particularly wine, reduce the risk of CHD. The present study was designed to investigate the effect of grape-skin extract on markers of oxidative status. The study was designed as a randomised crossover. A diet with a low content...... of flavonoids was served with strict control of intake in two consecutive 1-week intervention periods to fifteen subjects (nine women, six men) divided randomly into two groups. During one of the weeks the subjects from either group consumed 200 ml grape-skin extract in water (1 mg extract/ml) at each of three...... daily meals (31.3 mg total phenolics, including 9.0 mg catechin). An increased activity of glutathione reductase and a borderline increase of glutathione peroxidase activity in erythrocytes were observed after grape-skin intervention, while the intervention had no significant effect on superoxide...

  16. Anomalous skin effects in anisotropic kappa distributed plasmas

    Science.gov (United States)

    Khokhar, Tajammal H.; Bashir, M. F.; Murtaza, G.

    2017-07-01

    Anomalous skin effects (ASEs) are studied for the transverse electromagnetic waves in an unmagnetized collisionless plasma using anisotropic kappa distribution. The effects of the kappa spectral index (κ), temperature anisotropy ( A =T⊥/T||) , and the wave frequency (ω) on the ASEs are highlighted to be applicable for a wide range of plasma parameters. It is shown that the skin depth is reduced in a kappa distributed plasma as compared to the Maxwellian one. The anisotropy may enhance/reduce the skin depth depending upon the wave frequency to plasma frequency ratio ( ω/ωp ) and the regime of the anisotropy (i.e., A > 1 or A < 1). The results for the Maxwellian distribution ( κ→∞ ) are also retrieved. The possible applications to space and laboratory plasmas are also discussed.

  17. The effect of grape-skin extract on oxidative status

    DEFF Research Database (Denmark)

    Young, J. F.; Dragsted, L. O.; Daneshvar, B.

    2000-01-01

    Epidemiological studies indicate that moderate alcohol consumption, particularly wine, reduce the risk of CHD. The present study was designed to investigate the effect of grape-skin extract on markers of oxidative status. The study was designed as a randomised crossover. A diet with a low content...... of flavonoids was served with strict control of intake in two consecutive 1-week intervention periods to fifteen subjects (nine women, six men) divided randomly into two groups. During one of the weeks the subjects from either group consumed 200 ml grape-skin extract in water (1 mg extract/ml) at each of three...... daily meals (31.3 mg total phenolics, including 9.0 mg catechin). An increased activity of glutathione reductase and a borderline increase of glutathione peroxidase activity in erythrocytes were observed after grape-skin intervention, while the intervention had no significant effect on superoxide...

  18. Skin permeation enhancement effects of the gel and whole-leaf materials of Aloe vera, Aloe marlothii and Aloe ferox.

    Science.gov (United States)

    Fox, Lizelle T; Gerber, Minja; du Preez, Jan L; du Plessis, Jeanetta; Hamman, Josias H

    2015-01-01

    The aim of this study was to investigate the in-vitro permeation enhancement effects of the gel and whole-leaf materials of Aloe vera, Aloe marlothii and Aloe ferox using ketoprofen as a marker compound. The permeation studies were conducted across excised female abdominal skin in Franz diffusion cells, and the delivery of ketoprofen into the stratum corneum-epidermis and epidermis-dermis layers of the skin was investigated using a tape-stripping technique. A. vera gel showed the highest permeation-enhancing effect on ketoprofen (enhancement ratio or ER = 2.551) when compared with the control group, followed by A. marlothii gel (ER = 1.590) and A. ferox whole-leaf material (ER = 1.520). Non-linear curve fitting calculations indicated that the drug permeation-enhancing effect of A. vera gel can be attributed to an increased partitioning of the drug into the skin, while A. ferox whole leaf modified the diffusion characteristics of the skin for ketoprofen. The tape stripping results indicated that A. marlothii whole leaf delivered the highest concentration of the ketoprofen into the different skin layers. Of the selected aloe species investigated, A. vera gel material showed the highest potential as transdermal drug penetration enhancer across human skin. © 2014 Royal Pharmaceutical Society.

  19. Generation of Nonlinear Force Driven Blocks from Skin Layer Interaction of Petawatt-Picosecond Laser Pulses for ICF

    Institute of Scientific and Technical Information of China (English)

    Heinrich Hora; K. Jungwirth; B. Kralikova; J. Kraska; L. Laska; Liu Hong; G.H. Miley; P. Parys; Peng Hansheng; M. Pfeifer; K. Rohlena; Cang Yu; J. Skala; Z. Skladanowski; L. Torrisi; J. Ullschmied; J. Wolowski; Zhang Weiyan; He Xiantu; Zhang Jie; F. Osman; J. Badziak; F.P. Boody; S. Gammino; R. H(o)pfl

    2004-01-01

    The discovery of the essential difference of maximum ion energy for TW-ps laser plasma interaction compared with the 100 ns laser pulses [1] led to the theory of a skin layer model [2] where the control of prepulses suppressed the usual relativistic self-focusing. The subsequent generation of two nonlinear force driven blocks has been demonstrated experimentally and in extensive numerical studies where one block moves against the laser light and the other block into the irradiated target. These blocks of nearly solid state density DT plasma correspond to ion beam current densities [3] exceeding 1010 A/cm2 where the ion velocity can be chosen up to highly relativistic values. Using the results of the expected ignition of DT fuel by light ion beams, a selfsustained fusion reaction front may be generated even into uncompressed solid DT fuel similar to the Nuckolls-Wood [4] scheme where 10 kJ laser pulses produce 100 MJ fusion energy. This new and simplified scheme of laser-ICF needs and optimisation of the involved parameters.

  20. Two-dimensional effects in nonlinear Kronig-Penney models

    DEFF Research Database (Denmark)

    Gaididei, Yuri Borisovich; Christiansen, Peter Leth; Rasmussen, Kim

    1997-01-01

    An analysis of two-dimensional (2D) effects in the nonlinear Kronig-Penney model is presented. We establish an effective one-dimensional description of the 2D effects, resulting in a set of pseudodifferential equations. The stationary states of the 2D system and their stability is studied...

  1. Effects of graduated compression stockings on skin temperature after running.

    Science.gov (United States)

    Priego Quesada, J I; Lucas-Cuevas, A G; Gil-Calvo, M; Giménez, J V; Aparicio, I; Cibrián Ortiz de Anda, R M; Salvador Palmer, R; Llana-Belloch, S; Pérez-Soriano, P

    2015-08-01

    High skin temperatures reduce the thermal gradient between the core and the skin and they can lead to a reduction in performance and increased risk of injury. Graduated compression stockings have become popular among runners in the last years and their use may influence the athlete's thermoregulation. The aim of this study was to investigate the effects of graduated compression stockings on skin temperature during running in a moderate indoor environment. Forty-four runners performed two running tests lasting 30min (10min of warm-up and 20min at 75% of their maximal aerobic speed) with and without graduated compressive stockings. Skin temperature was measured in 12 regions of interest on the lower limb by infrared thermography before and after running. Heart rate and perception of fatigue were assessed during the last minute of the running test. Compression stockings resulted in greater increase of temperature (p=0.002 and ES=2.2, 95% CI [0.11-0.45°C]) not only in the body regions in contact (tibialis anterior, ankle anterior and gastrocnemius) but also in the body regions that were not in contact with the garment (vastus lateralis, abductor and semitendinosus). No differences were observed between conditions in heart rate and perception of fatigue (p>0.05 and ESrunning with graduated compression stockings produces a greater increase of skin temperature without modifying the athlete's heart rate and perception of fatigue. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Effects of microneedle system on the skin permeation of drugs

    OpenAIRE

    呉, 学明

    2007-01-01

    Microneedle systems have been paid attention as having many advantages overtransdermal patches and hypodermic needles. The procedure provides adequate skinpermeation rates without pain or severe infection. to obtain information for designing amicroneedle system, the pretreatment effect of microneedle puncture in the skin barrierstratum corneum on the in vitro skin permeatien of fluorescein isothiocyanate(FITC)一dextrans (4.3, 9.6 and 42.0 kDa) (FD-4, FD-10 and FD-40) was evaluated in hairlessr...

  3. MR imaging of skin biopsies for detection of irradiation effects

    Energy Technology Data Exchange (ETDEWEB)

    Chalansonnet, A.; Bonnat, J.L.; Briguet, A. [Centre National de la Recherche Scientifique (CNRS), 69 - Villeurbanne (France). Laboratoire de Resonance Magnetique Nucleaire; Bonnat, J.L.; Lefaix, J.L. [CEA Saclay, 91 - Gif-sur-Yvette (France). Dept. de Radiobiologie et de Radiopathologie

    1997-03-01

    During the last 20 years, several accidents occurred from inadvertent contact with sealed sources of {sup 192}Ir, {sup 60}Co and other radiation sources of industrial radiographers. Such accidents are characterized by a severe initial reaction progressing from erythema to necrosis at the sites of contact and sometimes by spontaneous resolution of the lesion over a few weeks period. The principal role of cutaneous tissue is to assume the barrier protection function against aggressions of the environment. Consequently, skin if directly concerned by irradiation damages. In this work we propose to examine the variations of the structure of irradiated skin using magnetic resonance micro-imaging. NMR micro imaging appears to be a preferment tool to observe irradiation of skin and may be useful for predictive and preventive detection of pathological effects of irradiation. (authors)

  4. Effective Architectural Design Decisions in Double Skin Facades

    Directory of Open Access Journals (Sweden)

    Tuğba İnan

    2013-06-01

    Full Text Available In architectural discourse, it is possible to notice a rising interest in building skin configurations which promise to help minimizing the loss of energy while maximizing its gain. In parallel, it is possible to see that the use of double-skin glass facades globally pervades. All over the world double-skin facade applications multiply day by day. This technology is still quite new in Turkey and it is not possible to find many applications or researches done on this subject. For this reason, architects and engineers should be focused on the designs solutions providing energy savings. The design of DSF depends on various architectural decisions. In this study, effective design decision parameters on energy performance of DSF systems will be discussed in a comprehensive way in architectural perspective by reviewing previous studies.

  5. Nonlinear Peltier effect and thermoconductance in nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Bogachek, E.N.; Scherbakov, A.G.; Landman, U. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430 (United States)

    1999-10-01

    A theoretical analysis of thermal transport in nanowires, in field-free conditions and under influence of applied magnetic fields, is presented. It is shown that in the nonlinear regime (finite applied voltage) new peaks in the Peltier coefficient appear leading to violation of Onsager{close_quote}s relation between the Peltier and thermopower coefficients. Oscillations of the Peltier coefficient in a magnetic field are demonstrated. The thermoconductance has a steplike quantized structure similar to the electroconductance and it exhibits deviations from the Wiedemann-Franz law. The strong dependence of the thermoconductance on the applied magnetic field leads to the possibility of magnetic blockade of thermal transport in wires with a small number of conducting channels. Possible control of thermal transport in nanowires through external parameters, that is applied through finite voltages and magnetic fields, is discussed. {copyright} {ital 1999} {ital The American Physical Society}

  6. Nonlinear Peltier effect and thermoconductance in nanowires

    Science.gov (United States)

    Bogachek, E. N.; Scherbakov, A. G.; Landman, Uzi

    1999-10-01

    A theoretical analysis of thermal transport in nanowires, in field-free conditions and under influence of applied magnetic fields, is presented. It is shown that in the nonlinear regime (finite applied voltage) new peaks in the Peltier coefficient appear leading to violation of Onsager's relation between the Peltier and thermopower coefficients. Oscillations of the Peltier coefficient in a magnetic field are demonstrated. The thermoconductance has a steplike quantized structure similar to the electroconductance and it exhibits deviations from the Wiedemann-Franz law. The strong dependence of the thermoconductance on the applied magnetic field leads to the possibility of magnetic blockade of thermal transport in wires with a small number of conducting channels. Possible control of thermal transport in nanowires through external parameters, that is applied through finite voltages and magnetic fields, is discussed.

  7. Third Order Nonlinear Optical Effects in Conjugated Polymers

    Science.gov (United States)

    Halvorson, Craig Steven

    Third order nonlinear optical effects in conjugated materials were studied using two different spectroscopic methods, third harmonic generation and two photon absorption. The third harmonic generation spectra of cis-polyacetylene, trans-polyacetylene, oriented trans-polyacetylene, three isomers of polyaniline, cis and trans-polyacetylene in polyvinyl butyral, polyheptdadiester, polyheptadiketone, and MEH-PPV/polyethylene blends were measured. The nonlinear optical susceptibility increases with structural order, and is enhanced by the presence of a degenerate ground state. The magnitude of the susceptibility reaches as high as 10^{-7} esu, which is sufficient for the creation of all-optical nonlinear devices. The two photon absorption spectrum of oriented transpolyacetylene was measured using nonlinear photothermal deflection. The spectrum reveals directly the Ag state at 1.1 eV in trans-polyacetylene, and reveals another Ag state at higher energy. The magnitude of the two photon absorption is large enough to rule out using trans-polyacetylene in serial all-optical nonlinear devices; all-optical devices made from conjugated polymers must be parallel, not serial. A new figure of merit for nonlinear devices was proposed.

  8. Research of secondary effects in nonlinear radio-location

    Directory of Open Access Journals (Sweden)

    M. V. Zinchenko

    2012-12-01

    Full Text Available Introduction. The basic setting of nonlinear radio-locator (NR in the field of technical guarding is the searching, identification and localization of radio-electronic mortgage devices − semiconductor nonlinear scatterers (NS. Statement of the problem. The NR efficiency increasing is possible by minimization of such factors influence as: presence of obstacle structures "metal-oxide-metal" (МОМ-structures in the investigated medium and presence of parasitic directional pattern lobe of emitting antenna. The analysis of nonlinear scatterers secondary unmasking features is considered. All possible regularities of the course of the phenomena and processes in the investigated medium, that are the consequence of nonlinear areas of NS semiconductor structures characteristics change (distortion under sounding radiation, are considered. Principal part. Researches showed that theoretically discovered effective radius change effect of nonlinear products dispersion of nonlinear scatterer response signal at the varying of nonlinear radio-locator sounding signal (SS power-level  allows to investigate the phenomenon of semiconductor structures characteristics of NS distortion at the action of relatively powerful ultrahigh frequency field. The effective radius change of nonlinear products dispersion of NS response signal at varying of exposing signal power-level is experimentally confirmed, which proves the possibility and expediency of the secondary unmasked features practice use for the search, identification and localization of NS in the technical guarding field: −     the area of looping appearance effect on functional dependence of response signal multiple harmonic level  from the sounding signal power-level [3]; −     effect of processes inertiality of semiconductor structures volt-ampere characteristics distortion [4]; −     phenomena of cross-correlation dependence of response signal chaotic state degree from the sounding signal

  9. Controlling ultrafast currents by the non-linear photogalvanic effect

    CERN Document Server

    Wachter, Georg; Lemell, Christoph; Tong, Xiao-Min; Yabana, Kazuhiro; Burgdörfer, Joachim

    2015-01-01

    We theoretically investigate the effect of broken inversion symmetry on the generation and control of ultrafast currents in a transparent dielectric (SiO2) by strong femto-second optical laser pulses. Ab-initio simulations based on time-dependent density functional theory predict ultrafast DC currents that can be viewed as a non-linear photogalvanic effect. Most surprisingly, the direction of the current undergoes a sudden reversal above a critical threshold value of laser intensity I_c ~ 3.8*10^13 W/cm2. We trace this switching to the transition from non-linear polarization currents to the tunneling excitation regime. We demonstrate control of the ultrafast currents by the time delay between two laser pulses. We find the ultrafast current control by the non-linear photogalvanic effect to be remarkably robust and insensitive to laser-pulse shape and carrier-envelope phase.

  10. Nonlinear spectral imaging of human normal skin, basal cell carcinoma and squamous cell carcinoma based on two-photon excited fluorescence and second-harmonic generation

    Science.gov (United States)

    Xiong, S. Y.; Yang, J. G.; Zhuang, J.

    2011-10-01

    In this work, we use nonlinear spectral imaging based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) for analyzing the morphology of collagen and elastin and their biochemical variations in basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and normal skin tissue. It was found in this work that there existed apparent differences among BCC, SCC and normal skin in terms of their thickness of the keratin and epithelial layers, their size of elastic fibers, as well as their distribution and spectral characteristics of collagen. These differences can potentially be used to distinguish BCC and SCC from normal skin, and to discriminate between BCC and SCC, as well as to evaluate treatment responses.

  11. Coriolis effects on nonlinear oscillations of rotating cylinders and rings

    Science.gov (United States)

    Padovan, J.

    1976-01-01

    The effects which moderately large deflections have on the frequency spectrum of rotating rings and cylinders are considered. To develop the requisite solution, a variationally constrained version of the Lindstedt-Poincare procedure is employed. Based on the solution developed, in addition to considering the effects of displacement induced nonlinearity, the role of Coriolis forces is also given special consideration.

  12. Zeno effect and switching of solitons in nonlinear couplers

    DEFF Research Database (Denmark)

    Abdullaev, F Kh; Konotop, V V; Ögren, Magnus;

    2011-01-01

    The Zeno effect is investigated for soliton type pulses in a nonlinear directional coupler with dissipation. The effect consists in increase of the coupler transparency with increase of the dissipative losses in one of the arms. It is shown that localized dissipation can lead to switching...

  13. Beer and beer compounds: physiological effects on skin health.

    Science.gov (United States)

    Chen, W; Becker, T; Qian, F; Ring, J

    2014-02-01

    Beer is one of the earliest human inventions and globally the most consumed alcoholic beverage in terms of volume. In addition to water, the 'German Beer Purity Law', based on the Bavarian Beer Purity Law from 1516, allows only barley, hops, yeasts and water for beer brewing. The extracts of these ingredients, especially the hops, contain an abundance of polyphenols such as kaempferol, quercetin, tyrosol, ferulic acid, xanthohumol/isoxanthohumol/8-prenylnaringenin, α-bitter acids like humulone and β-bitter acids like lupulone. 8-prenylnaringenin is the most potent phytoestrogen known to date. These compounds have been shown to possess various anti-bacterial, anti-inflammatory, anti-oxidative, anti-angiogenic, anti-melanogenic, anti-osteoporotic and anti-carcinogenic effects. Epidemiological studies on the association between beer drinking and skin disease are limited while direct evidence of beer compounds in clinical application is lacking. Potential uses of these substances in dermatology may include treatment of atopic eczema, contact dermatitis, pigmentary disorders, skin infections, skin ageing, skin cancers and photoprotections, which require an optimization of the biostability and topical delivery of these compounds. Further studies are needed to determine the bioavailability of these compounds and their possible beneficial health effects when taken by moderate beer consumption. © 2013 European Academy of Dermatology and Venereology.

  14. Nonlinear effects generation in non-adiabatically tapered fibres

    Science.gov (United States)

    Palací, Jesús; Mas, Sara; Monzón-Hernández, David; Martí, Javier

    2015-12-01

    Nonlinear effects are observed in a non-adiabatically tapered optical fibre. The designed structure allows for the introduction of self-phase modulation, which is observed through pulse breaking and spectral broadening, in approximately a centimetre of propagation using a commercial telecom laser. These devices are simple to fabricate and suitable to generate and control a variety of nonlinear effects in practical applications because they do not experience short-term degradation as previously reported approaches. Experimental and theoretical results are obtained, showing a good agreement.

  15. Nonlinear Peltier effect and the nonequilibrium Jonson-Mahan theorem

    OpenAIRE

    Freericks, J. K.; Zlatic, V.

    2006-01-01

    We generalize the many-body formalism for the Peltier effect to the nonlinear/nonequilibrium regime corresponding to large amplitude (spatially uniform but time-dependent) electric fields. We find a relationship between the expectation values for the charge current and for the part of the heat current that reduces to the Jonson-Mahan theorem in the linear-response regime. The nonlinear-response Peltier effect has an extra term in the heat current that is related to Joule heating (we are unabl...

  16. Sensory neuropeptide effects in human skin.

    OpenAIRE

    Fuller, R W; Conradson, T. B.; Dixon, C M; Crossman, D.C.; Barnes, P. J.

    1987-01-01

    1 Neuropeptides released from sensory nerves may account for cutaneous flare and wheal following local trauma. In 28 normal subjects we have studied the effects of four sensory neuropeptides given by intradermal injection on the forearm or back. 2 All peptides caused a flare distant from the site of injection, presumably due to an axon reflex. Substance P (SP) was the most potent (geometric mean dose causing 50% of maximum flare, 4.2 pmol). Neurokinin A (NKA) was the next most potent with neu...

  17. Thermal diffusivity effect in opto-thermal skin measurements

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, P; Imhof, R E [Faculty of ESBE, London South Bank University, 103 Borough Road, London SE1 0AA (United Kingdom); Cui, Y [Sunrise Systems Limited, Flint Bridge Business Centre, Ely Road, Waterbeach, Cambridge CB5 9QZ (United Kingdom); Ciortea, L I; Berg, E P, E-mail: xiaop@lsbu.ac.u [Biox Systems Ltd, 103 Borough Road, London SE1 0AA (United Kingdom)

    2010-03-01

    We present our latest study on the thermal diffusivity effect in opto-thermal skin measurements. We discuss how thermal diffusivity affects the shape of opto-thermal signal, and how to measure thermal diffusivity in opto-thermal measurements of arbitrary sample surfaces. We also present a mathematical model for a thermally gradient material, and its corresponding opto-thermal signal. Finally, we show some of our latest experimental results of this thermal diffusivity effect study.

  18. Effect of Age on Tooth Shade, Skin Color and Skin-Tooth Color Interrelationship in Saudi Arabian Subpopulation

    Science.gov (United States)

    Haralur, Satheesh B

    2015-01-01

    Background: Dental restoration or prosthesis in harmony with adjacent natural teeth color is indispensable part for the successful esthetic outcome. The studies indicate is existence of correlation between teeth and skin color. Teeth and skin color are changed over the aging process. The aim of the study was to explore the role of age on the tooth and skin color parameters, and to investigate the effect of ageing on teeth-skin color correlation. Materials and Methods: Total of 225 Saudi Arabian ethnic subjects was divided into three groups of 75 each. The groups were divided according to participant’s age. The participant’s age for Group I, Group II, and Group III was 18-29 years, 30-50 years, and above 50 years, respectively. The tooth color was identified by spectrophotometer in CIE Lab parameters. The skin color was registered with skin surface photography. The data were statistically analyzed with one-way ANOVA and correlation tests with SPSS 18 software. Results: The Group I had the highest ‘L’ value of 80.26, Group III recorded the least value of 76.66. The Group III had highest yellow value ‘b’ at 22.72, while Group I had 19.19. The skin ‘L’ value was highest in the young population; the elder population had the increased red value ‘a’ in comparison to younger subjects. The ‘L’ tooth color parameter had a strong positive linear correlation with skin color in young and adult subjects. While Group III teeth showed the strong positive correlation with ‘b’ parameter at malar region. Conclusion: The elder subjects had darker and yellow teeth in comparison with younger subjects. The reddening of the skin was observed as age-related skin color change. The age had a strong influence on the teeth-skin color correlation. PMID:26464536

  19. Effect of scalar nonlinearity on zonal flow generation by Rossby waves

    NARCIS (Netherlands)

    Mikhailovskii, A. B.; Lominadze, J. G.; Erokhin, N. N.; Erokhin, N. S.; Smolyakov, A. I.; Tsypin, V. S.

    2007-01-01

    Effects of scalar nonlinearity on the generation of zonal flow by Rossby waves in shallow rotating fluid are considered. Zonal flows are generated via the action of Reynolds stress due to vector nonlinearity together with the effects of scalar nonlinearity. It is shown that the scalar nonlinearity r

  20. Effects of Essential Oils and Polyunsaturated Fatty Acids on Canine Skin Equivalents: Skin Lipid Assessment and Morphological Evaluation

    Directory of Open Access Journals (Sweden)

    S. Cerrato

    2013-01-01

    Full Text Available A canine skin equivalent model has been validated for the assessment of a topical formulation effects. Skin equivalents were developed from freshly isolated cutaneous canine fibroblasts and keratinocytes, after enzymatic digestion of skin samples (n=8 from different breeds. Fibroblasts were embedded into a collagen type I matrix, and keratinocytes were seeded onto its surface at air-liquid interface. Skin equivalents were supplemented with essential oils and polyunsaturated fatty acid formulation or with vehicle. Skin equivalents were histopathologically and ultrastructurally studied, and the three main lipid groups (free fatty acids, cholesterol, and ceramides were analyzed. Results showed that the culture method developed resulted in significant improvements in cell retrieval and confluence. Treated samples presented a thicker epidermis with increased number of viable cell layers, a denser and compact stratum corneum, and a more continuous basal membrane. Regarding lipid profile, treated skin equivalents showed a significant increase in ceramide content (51.7±1.3 when compared to untreated (41.6 ± 1.4 samples. Ultrastructural study evidenced a compact and well-organized stratum corneum in both treated and control skin equivalents. In conclusion, cell viability and ceramides increase, after lipid supplementation, are especially relevant for the treatment of skin barrier disruptions occurring in canine atopic dermatitis.

  1. Nonlinear dispersion effects in elastic plates: numerical modelling and validation

    Science.gov (United States)

    Kijanka, Piotr; Radecki, Rafal; Packo, Pawel; Staszewski, Wieslaw J.; Uhl, Tadeusz; Leamy, Michael J.

    2017-04-01

    Nonlinear features of elastic wave propagation have attracted significant attention recently. The particular interest herein relates to complex wave-structure interactions, which provide potential new opportunities for feature discovery and identification in a variety of applications. Due to significant complexity associated with wave propagation in nonlinear media, numerical modeling and simulations are employed to facilitate design and development of new measurement, monitoring and characterization systems. However, since very high spatio- temporal accuracy of numerical models is required, it is critical to evaluate their spectral properties and tune discretization parameters for compromise between accuracy and calculation time. Moreover, nonlinearities in structures give rise to various effects that are not present in linear systems, e.g. wave-wave interactions, higher harmonics generation, synchronism and | recently reported | shifts to dispersion characteristics. This paper discusses local computational model based on a new HYBRID approach for wave propagation in nonlinear media. The proposed approach combines advantages of the Local Interaction Simulation Approach (LISA) and Cellular Automata for Elastodynamics (CAFE). The methods are investigated in the context of their accuracy for predicting nonlinear wavefields, in particular shifts to dispersion characteristics for finite amplitude waves and secondary wavefields. The results are validated against Finite Element (FE) calculations for guided waves in copper plate. Critical modes i.e., modes determining accuracy of a model at given excitation frequency - are identified and guidelines for numerical model parameters are proposed.

  2. Nonlinear Effects in the Amplitude of Cosmological Density Fluctuations

    CERN Document Server

    Juszkiewicz, Roman; Fry, J N; Jaffe, Andrew H

    2009-01-01

    The amplitude of cosmological density fluctuations, $\\sigma_8$, has been studied and estimated by analysing many cosmological observations. The values of the estimates vary considerably between the various probes. However, different estimators probe the value of $\\sigma_8$ in different cosmological scales and do not take into account the nonlinear evolution of the parameter at late times. We show that estimates of the amplitude of cosmological density fluctuations derived from cosmic flows are systematically higher than those inferred at early epochs because of nonlinear evolution at later times. Here we derive corrections to the value of $\\sigma_8$ and compare amplitudes after accounting for this effect.

  3. Clinical effects of an oral supplement rich in antioxidants on skin radiance in women

    OpenAIRE

    Dumoulin M; Gaudout D; Lemaire B

    2016-01-01

    Marion Dumoulin, David Gaudout, Benoit Lemaire Activ’Inside, Libourne, France Background: Environmental factors impact the skin aging resulting in decrease of skin radiance. Nutrition and particularly antioxidants could help to fight against skin degradation.Objective: The aim of this study was to evaluate the effects of an oral supplement rich in specific antioxidants, SkinAx2TM, on the improvement of the skin radiance in women.Methods: The open-label clinical stu...

  4. Clinical effects of an oral supplement rich in antioxidants on skin radiance in women

    OpenAIRE

    Dumoulin M; Gaudout D; Lemaire B

    2016-01-01

    Marion Dumoulin, David Gaudout, Benoit Lemaire Activ’Inside, Libourne, France Background: Environmental factors impact the skin aging resulting in decrease of skin radiance. Nutrition and particularly antioxidants could help to fight against skin degradation.Objective: The aim of this study was to evaluate the effects of an oral supplement rich in specific antioxidants, SkinAx2TM, on the improvement of the skin radiance in women.Methods: The open-label clinical stu...

  5. Nutritional skin care : health effects of micronutrients and fatty acids

    NARCIS (Netherlands)

    Boelsma, E.; Hendriks, H.F.J.; Roza, L.

    2001-01-01

    Human skin is continuously exposed to internal and external influences that may alter its condition and functioning. As a consequence, the skin may undergo alterations leading to photoaging, inflammation, immune dysfunction, imbalanced epidermal homeostasis, or other skin disorders. Modern

  6. Evaluation of skin viability effect on ethosome and liposome-mediated psoralen delivery via cell uptake.

    Science.gov (United States)

    Zhang, Yong-Tai; Shen, Li-Na; Wu, Zhong-Hua; Zhao, Ji-Hui; Feng, Nian-Ping

    2014-10-01

    This study investigated the effect of skin viability on its permeability to psoralen delivered by ethosomes, as compared with liposomes. With decreasing skin viability, the amount of liposome-delivered psoralen that penetrated through the skin increased, whereas skin deposition of psoralen from both ethosomes and liposomes reduced. Psoralen delivery to human-immortalized epidermal cells was more effective using liposomes, whereas delivery to human embryonic skin fibroblast cells was more effective when ethosomes were used. These findings agreed with those of in vivo studies showing that skin psoralen deposition from ethosomes and liposomes first increased and then plateaued overtime, which may indicate gradual saturation of intracellular drug delivery. It also suggested that the reduced deposition of ethosome- or liposome-delivered psoralen in skin with reduced viability may relate to reduced cellular uptake. This work indicated that the effects of skin viability should be taken into account when evaluating nanocarrier-mediated drug skin permeation.

  7. Study On Nonlinear effect In 2D Plastic Media

    Science.gov (United States)

    Wenjie, D.; Chen, X.

    2011-12-01

    Unlike the perfect elastic, homogeneous and isotropic model, the properties of real earth media are heterogeneous, plastic and anisotropic to a certain extend. To accurately simulate the strong ground motion in a basin, nonlinear or plastic effect should be considered in simulation. In this study, we use DRP/opt MacCormack non-staggered finite difference method to simulate 2D seismic wave propagation in anisotropic and plastic media. Compared with the traditional staggered grid FDM, this scheme is more accurate and more efficient. We focus on the nonlinear character of the sedimentary basin model. The preliminary ground motion results indicate that the energy of seismic wave has obvious nonlinear dissipation and irreversible deformations which is danger to buildings in the sedimentary basin.

  8. The effect of nonlinearity on unstable zones of Mathieu equation

    Indian Academy of Sciences (India)

    M GH SARYAZDI

    2017-03-01

    Mathieu equation is a well-known ordinary differential equation in which the excitation term appears as the non-constant coefficient. The mathematical modelling of many dynamic systems leads to Mathieu equation. The determination of the locus of unstable zone is important for the control of dynamic systems. In this paper, the stable and unstable regions of Mathieu equation are determined for three cases of linear and nonlinear equations using the homotopy perturbation method. The effect of nonlinearity is examined in the unstable zone. The results show that the transition curves of linear Mathieu equation depend on the frequency of the excitation term. However, for nonlinear equations, the curves depend also on initial conditions. In addition, increasing the amplitude of response leads to an increase in the unstable zone.

  9. Effective Dielectric Response of Nonlinear Composites of Coated Metal Inclusions

    Institute of Scientific and Technical Information of China (English)

    CHEN Guo-Qing; WU Ya-Min

    2007-01-01

    The effective dielectric response of the composites in which nondilute coated metal particles are randomly embedded in a linear host is investigated. Two types of coated particles are considered, one is that the core is nonlinear, the other is that the shell is nonlinear. We derive general expressions for the effective linear dielectric function and the effective third-order nonlinear susceptibility, and take one step forward to perform numerical calculations on the coated metal/dielectric composites. Numerical results show that the effective linear and nonlinear dielectric responses can be greatly enhanced near the surface plasmon resonant frequency. Moreover, the resonant peaks are found within a range from 0.46ωp to 0.57ωp for spherical particles and from 0.59ωp to 0.7ωp for cylindrical inclusions. In the frequency region, the resonant peak can achieve the maximum, according to an optimal structural parameter and volume fraction. The resonant frequency exhibits a redshift with the increasing structural parameter k or volume fraction f or dimensionality factor D.

  10. Conditional linear-optical measurement schemes generate effective photon nonlinearities

    CERN Document Server

    Lapaire, G G; Dowling, J P; Sipe, J E; Dowling, Jonathan P.

    2003-01-01

    We provide a general approach for the analysis of optical state evolution under conditional measurement schemes, and identify the necessary and sufficient conditions for such schemes to simulate unitary evolution on the freely propagating modes. If such unitary evolution holds, an effective photon nonlinearity can be identified. Our analysis extends to conditional measurement schemes more general than those based solely on linear optics.

  11. Spontaneous emission and nonlinear effects in photonic bandgap materials

    Science.gov (United States)

    Fogel, Ishella S.; Bendickson, Jon M.; Tocci, Michael D.; Bloemer, Mark J.; Scalora, Michael; Bowden, Charles M.; Dowling, Jonathan P.

    1998-03-01

    We summarize and review our theoretical and experimental work on spontaneous emission and nonlinear effects in one-dimensional, photonic bandgap (PBG) structures. We present a new result: a method for calculating the normal-mode solutions - and hence the spontaneous emission of embedded emitters - in an arbitrary, linear, lossless, one-dimensional, PBG structure.

  12. The effect of various avocado oils on skin collagen metabolism.

    Science.gov (United States)

    Werman, M J; Mokady, S; Nimni, M E; Neeman, I

    1991-01-01

    The effects of various avocado oils on collagen metabolism in skin were studied in growing rats fed diets containing 10% (w/w) of the tested oils. Rats fed the unrefined avocado oil extracted with hexane from the intact fruit, its unsaponifiables or the avocado seed oil, showed significant increases in soluble collagen content in skin, though total collagen content was not affected. The increased soluble collagen content appears to be a consequence of the inhibition of lysyl oxidase activity. The active factor was found to be present in the unrefined avocado oil and probably originated from the avocado seed, since collagen metabolism was affected only by fractions which contained lipids fraction from the seed. In comparison rats fed the refined or unrefined soybean oils showed no effects.

  13. Measuring the Non-Linear Effects of Monetary Policy

    OpenAIRE

    Christian Matthes; Regis Barnichon

    2015-01-01

    This paper proposes a method to identify the non-linear effects of structural shocks by using Gaussian basis functions to parametrize impulse response functions. We apply our approach to monetary policy and find that the effect of a monetary intervention depends strongly on (i) the sign of the intervention, (ii) the size of the intervention, and (iii) the state of the business cycle at the time of the intervention. A contractionary policy has a strong adverse effect on output, much stronger t...

  14. Skin-sparing effects of neutron beam filtering materials.

    Science.gov (United States)

    Otte, V A; Almond, P R; Smathers, J B; Attix, F H

    1987-01-01

    The skin-sparing effects of several filtering materials for fast neutron beams were studied under various conditions. A parallel-plate ionization chamber was used for the measurements. The parameters which were studied included field size, distance from filter to ion chamber, filter material, and filter thickness. On the basis of this work, Teflon (polytetrafluoroethylene) was chosen for fabrication of flattening filters and wedges.

  15. Experimental observations of nonlinear effects of the Lamb waves

    Institute of Scientific and Technical Information of China (English)

    DENG Mingxi; D.C. Price; D.A.Scott

    2004-01-01

    The experimental observations of nonlinear effects of the primary Lamb waves have been reported. Firstly, the brief descriptions have been made for the nonlinear acoustic measurement system developed by Ritec. The detailed considerations for the acoustic experiment system established for observing of the nonlinear effects of the primary Lamb waves have been carried out. Especially, the analysis focuses on the time-domain responses of second harmonics of the primary Lame waves by employing a straightforward model. Based on the existence conditions of strong nonlinearity of the primary Lamb waves, the wedge transducers are designed to generate and detect the primary and secondary waves on the surface of an aluminum sheet. For the different distances between the transmitting and receiving wedge transducers,the amplitudes of the primary waves and the second harmonics on the sheet surface have been measured within a specified frequency range. In the immediate vicinity of the driving frequency,where the primary and the double frequency Lamb waves have the same phase velocities, the quantitative relations of second-harmonic amplitudes with the propagation distance have been analyzed. It is experimentally verified that the second harmonics of the primary Lamb waves do have a cumulative growth effect along with the propagation distance.

  16. Nonlinear dielectric effects in liquids: a guided tour

    Science.gov (United States)

    Richert, Ranko

    2017-09-01

    Dielectric relaxation measurements probe how the polarization of a material responds to the application of an external electric field, providing information on structure and dynamics of the sample. In the limit of small fields and thus linear response, such experiments reveal the properties of the material in the same thermodynamic state it would have in the absence of the external field. At sufficiently high fields, reversible changes in enthalpy and entropy of the system occur even at constant temperature, and these will in turn alter the polarization responses. The resulting nonlinear dielectric effects feature field induced suppressions (saturation) and enhancements (chemical effect) of the amplitudes, as well as time constant shifts towards faster (energy absorption) and slower (entropy reduction) dynamics. This review focuses on the effects of high electric fields that are reversible and observed at constant temperature for single component glass-forming liquids. The experimental challenges involved in nonlinear dielectric experiments, the approaches to separating and identifying the different sources of nonlinear behavior, and the current understanding of how high electric fields affect dielectric materials will be discussed. Covering studies from Debye’s initial approach to the present state-of-the-art, it will be emphasized what insight can be gained from the nonlinear responses that are not available from dielectric relaxation results obtained in the linear regime.

  17. Chimney Effect Assessment of the Double-skin Facade

    Institute of Scientific and Technical Information of China (English)

    QIU Zhong-zhu; LI Peng; CHOW Tin-tai; REN Jian-xing; WANG Wen-huan

    2009-01-01

    The mathematic model of heat transfer through ventihted double glazing was verified with themeasured data,which were from a test chamber equipped with glass face temperature,solar radiation,ambient temperature,and wind speed measurement facility.Mter the model validation,the double-skin facade assess-ment was carried out through simulation with ESP-r software integrating thermal simulation and air low net work module.The air flow situation in the air gap was analyzed on the basis of the hourly air velocity simulation data within typical winter week,summer week,spring week and autumn week.The differences of chimney ef-fect in different seasons were discussed,and the thermal loads resulted from the ventilated and unventihted dou-ble skin facade were presented.

  18. Silica holey fibres: fabrication and nonlinear effects

    OpenAIRE

    Belardi, W.; Monro, T.M.; Lee, J.H.; Yusoff, Z.; Price, J.H.V.; Malinowski, A.; Piper, A; Richardson, D J

    2002-01-01

    Holey fibres (HFs) [1] have emerged as a novel class of optical fibres which can provide completely new optical properties, such as endlessly single mode operation and novel dispersion properties as anomalous dispersion below 1.3µm, broadband flat dispersion and highly normal dispersion at 1.55µm. Moreover by changing the HF parameters (i.e. hole and core size), it is possible to fabricate HFs with an effective area so high as 800µm2 or so low as approximately 1µm2 [2]. A holey fibre perform ...

  19. Dynamic nonlinear thermal optical effects in coupled ring resonators

    Directory of Open Access Journals (Sweden)

    Chenguang Huang

    2012-09-01

    Full Text Available We investigate the dynamic nonlinear thermal optical effects in a photonic system of two coupled ring resonators. A bus waveguide is used to couple light in and out of one of the coupled resonators. Based on the coupling from the bus to the resonator, the coupling between the resonators and the intrinsic loss of each individual resonator, the system transmission spectrum can be classified by three different categories: coupled-resonator-induced absorption, coupled-resonator-induced transparency and over coupled resonance splitting. Dynamic thermal optical effects due to linear absorption have been analyzed for each category as a function of the input power. The heat power in each resonator determines the thermal dynamics in this coupled resonator system. Multiple “shark fins” and power competition between resonators can be foreseen. Also, the nonlinear absorption induced thermal effects have been discussed.

  20. The severity of Osteogenesis imperfecta and type I collagen pattern in human skin as determined by nonlinear microscopy: proof of principle of a diagnostic method.

    Directory of Open Access Journals (Sweden)

    Javier Adur

    Full Text Available BACKGROUND: The confirmatory diagnosis of Osteogenesis Imperfecta (OI requires invasive, commonly bone biopsy, time consuming and destructive methods. This paper proposes an alternative method using a combination of two-photon excitation fluorescence (TPEF and second-harmonic generation (SHG microscopies from easily obtained human skin biopsies. We show that this method can distinguish subtypes of human OI. METHODOLOGY/PRINCIPAL FINDINGS: Different aspects of collagen microstructure of skin fresh biopsies and standard H&E-stained sections of normal and OI patients (mild and severe forms were distinguished by TPEF and SHG images. Moreover, important differences between subtypes of OI were identified using different methods of quantification such as collagen density, ratio between collagen and elastic tissue, and gray-level co-occurrence matrix (GLCM image-pattern analysis. Collagen density was lower in OI dermis, while the SHG/autofluorescence index of the dermis was significantly higher in OI as compared to that of the normal skin. We also showed that the energy value of GLCM texture analysis is useful to discriminate mild from severe OI and from normal skin. CONCLUSIONS/SIGNIFICANCE: This work demonstrated that nonlinear microscopy techniques in combination with image-analysis approaches represent a powerful tool to investigate the collagen organization in skin dermis in patients with OI and has the potential to distinguish the different types of OI. The procedure outlined in this paper requires a skin biopsy, which is almost painless as compared to the bone biopsy commonly used in conventional methods. The data presented here complement existing clinical diagnostic techniques and can be used as a diagnostic procedure to confirm the disease, evaluate its severity and treatment efficacy.

  1. An effective, cosmetically acceptable, novel hydro-gel emollient for the management of dry skin conditions.

    Science.gov (United States)

    Wynne, A; Whitefield, M; Dixon, A J; Anderson, S

    2002-06-01

    A novel hydro-gel emollient (Doublebase) has been developed with improved moisturizing effects. To test this novel hydro-gel for its moisturizing effect, for its potential to cause skin irritancy/allergy and for its clinical effectiveness and acceptability in dry skin conditions. Skin hydration (corneometry) and trans-epidermal water loss (TEWL) studies with a single application in 18 volunteers confirmed its efficacy (p effectiveness of Doublebase was demonstrated in an open study of 78 patients with dry skin conditions. Doublebase may be considered a suitable preparation that can be used effectively by most patients with dry skin conditions.

  2. Effects of cream containing ficus carica L. fruit extract on skin parameters: In vivo evaluation

    Directory of Open Access Journals (Sweden)

    H Khan

    2014-01-01

    Full Text Available This study was aimed to investigate the effects of cream containing Ficus carica L. fruit ([Figure 1] extract on various skin parameters such as skin melanin, erythema, moisture content, trans-epidermal water loss and sebum. For this purpose, formulation with 4% concentrated extract of F. carica fruit and base without extract were developed. Base served as a control. Both base and formulation were applied to the cheeks of human volunteers for 8 weeks to investigate the effects on different skin parameters using non-invasive bioengineering instruments. Formulation decreased the skin melanin, trans-epidermal water loss and skin sebum significantly. Formulation increased the skin hydration significantly and insignificant effects on skin erythema. We concluded that a stable topical cream (w/o emulsion containing F. carica fruit extract have effects on skin melanin, trans-epidermal loss, hydration values and sebum content and possibly could be used against for hyper pigmentation, acne, freckles and wrinkle.

  3. Effect on Microbial Growth of a New Skin Protectant Formulation

    Science.gov (United States)

    Stoffel, Joseph; Bernatchez, Stéphanie F.

    2017-01-01

    Objective: Evaluate the effect of a new investigational skin protectant formulation on the growth of various microorganisms in vitro. Approach: An in vitro laboratory assay with various species of gram-positive bacteria, gram-negative bacteria, and yeast grown on agar plates was used to verify that a new investigational product used for the management of incontinence-associated dermatitis (IAD) does not support microbial growth. Results: The investigational product did not support the growth of all organisms tested for 48 h in these assays. The results demonstrate the barrier properties of this investigational formulation against bacteria and yeast that are relevant to incontinent patients. Innovation: IAD accompanied by skin damage is difficult to manage with currently available products. A new skin protectant that can be applied as a liquid and polymerizes into a breathable film in situ even in the presence of exudate (as shown previously) has been developed and tested to ensure that it does not support microbial growth. Conclusion: This work verifies that this new product does not support microbial growth in vitro using organisms relevant for the intended application. PMID:28289552

  4. The effect of various dietary fats on skin tumor initiation.

    Science.gov (United States)

    Locniskar, M; Belury, M A; Cumberland, A G; Patrick, K E; Fischer, S M

    1991-01-01

    The type of dietary fat has been shown to modulate the initiation stage of mammary tumorigenesis, with saturated fat fed before and/or during carcinogen treatment resulting in increased tumor incidence. This study was designed to determine whether different types of dietary fat alter the initiation stage of skin carcinogenesis by use of the initiation-promotion mouse skin carcinogenesis model. Sencar mice were divided into three groups and maintained on one of the experimental diets. The AIN-76-based diets consisted of 10% total fat with various types of fat: 8.5% menhaden oil plus 1.5% corn oil, 8.5% coconut oil plus 1.5% corn oil, and 10% corn oil. After three weeks mice were initiated with 10 nmol dimethylbenz[a]anthracene (DMBA). Two weeks later, all mice were switched to a diet containing 5% corn oil. Promotion began four weeks after initiation with twice-weekly application of 1 microgram 12-O-tetradecanoylphorbol-13-acetate and continued for 12 weeks. No statistically significant differences in kilocalories of food consumed or body weights were observed between diet groups during the study. The final papilloma incidence, yield, and size were not significantly different among the diet groups. In a parallel study, [3H]DMBA binding to epidermal DNA showed no dietary differences. Unlike the mammary carcinogenesis model, these data suggest that the type of fat fed during DMBA initiation had minimal effects on this stage of skin carcinogenesis.

  5. Effects of noise on the phase dynamics of nonlinear oscillators

    Science.gov (United States)

    Daffertshofer, A.

    1998-07-01

    Various properties of human rhythmic movements have been successfully modeled using nonlinear oscillators. However, despite some extensions towards stochastical differential equations, these models do not comprise different statistical features that can be explained by nondynamical statistics. For instance, one observes certain lag one serial correlation functions for consecutive periods during periodic motion. This work aims at an extension of dynamical descriptions in terms of stochastically forced nonlinear oscillators such as ξ¨+ω20ξ=n(ξ,ξ˙)+q(ξ,ξ˙)Ψ(t), where the nonlinear function n(ξ,ξ˙) generates a limit cycle and Ψ(t) denotes colored noise that is multiplied via q(ξ,ξ˙). Nonlinear self-excited systems have been frequently investigated, particularly emphasizing stability properties and amplitude evolution. Thus, one can focus on the effects of noise on the frequency or phase dynamics that can be analyzed by use of time-dependent Fokker-Planck equations. It can be shown that noise multiplied via polynoms of arbitrary finite order cannot generate the desired period correlation but predominantly results in phase diffusion. The system is extended in terms of forced oscillators in order to find a minimal model producing the required error correction.

  6. Nonlinear Resonance Islands and Modulational Effects in a Proton Synchrotron

    Energy Technology Data Exchange (ETDEWEB)

    Satogata, Todd Jeffrey [Northwestern Univ., Evanston, IL (United States)

    1993-01-01

    We examine both one-dimensional and two-dimensional nonlinear resonance islands created in the transverse phase space of a proton synchrotron by nonlinear magnets. We also examine application of the theoretical framework constructed to the phenomenon of modulational diffusion in a collider model of the Fermilab Tevatron. For the one-dimensional resonance island system, we examine the effects of two types of modulational perturbations on the stability of these resonance islands: tune modulation and beta function modulation. Hamiltonian models are presented which predict stability boundaries that depend on only three paramders: the strength and frequency of the modulation and the frequency of small oscillations inside the resonance island. These. models are compared to particle tracking with excellent agreement. The tune modulation model is also successfully tested in experiment, where frequency domain analysis coupled with tune modulation is demonstrated to be useful in measuring the strength of a nonlinear resonance. Nonlinear resonance islands are also examined in two transverse dimensions in the presence of coupling and linearly independent crossing resonances. We present a first-order Hamiltonian model which predicts fixed point locations, but does not reproduce small oscillation frequencies seen in tracking; therefore in this circumstance such a model is inadequate. Particle tracking is presented which shows evidence of two-dimensional persistent signals, and we make suggestions on methods for observing such signals in future experiment.

  7. Analytical treatment of the nonlinear electron cloud effect and the combined effects with beam-beam and space charge nonlinear forces in storage rings

    Institute of Scientific and Technical Information of China (English)

    GAO Jie

    2009-01-01

    In this paper we treat first some nonlinear beam dynamics problems in storage rings, such as beam dynamic apertures due to magnetic multipoles, wiggles, beam-beam effects, nonlinear space charge effect, and then nonlinear electron cloud effect combined with beam-beam and space charge effects, analytically. This analytical treatment is applied to BEPC Ⅱ. The corresponding analytical expressions developed in this paper are useful both in understanding the physics behind these problems and also in making practical quick hand estimations.

  8. Effect of oral intake of choline-stabilized orthosilicic acid on skin, nails and hair in women with photodamaged skin.

    Science.gov (United States)

    Barel, A; Calomme, M; Timchenko, A; De Paepe, K; Paepe, K De; Demeester, N; Rogiers, V; Clarys, P; Vanden Berghe, D

    2005-10-01

    Chronic exposure of the skin to sunlight causes damage to the underlying connective tissue with a loss of elasticity and firmness. Silicon (Si) was suggested to have an important function in the formation and maintenance of connective tissue. Choline-stabilized orthosilicic acid ("ch-OSA") is a bioavailable form of silicon which was found to increase the hydroxyproline concentration in the dermis of animals. The effect of ch-OSA on skin, nails and hair was investigated in a randomized, double blind, placebo-controlled study. Fifty women with photodamaged facial skin were administered orally during 20 weeks, 10 mg Si/day in the form of ch-OSA pellets (n=25) or a placebo (n=25). Noninvasive methods were used to evaluate skin microrelief (forearm), hydration (forearm) and mechanical anisotropy (forehead). Volunteers evaluated on a virtual analog scale (VAS, "none=0, severe=3") brittleness of hair and nails. The serum Si concentration was significantly higher after a 20-week supplementation in subjects with ch-OSA compared to the placebo group. Skin roughness parameters increased in the placebo group (Rt:+8%; Rm: +11%; Rz: +6%) but decreased in the ch-OSA group (Rt: -16%; Rm: -19%; Rz: -8%). The change in roughness from baseline was significantly different between ch-OSA and placebo groups for Rt and Rm. The difference in longitudinal and lateral shear propagation time increased after 20 weeks in the placebo group but decreased in the ch-OSA group suggesting improvement in isotropy of the skin. VAS scores for nail and hair brittleness were significantly lower after 20 weeks in the ch-OSA group compared to baseline scores. Oral intake of ch-OSA during the 20 weeks results in a significant positive effect on skin surface and skin mechanical properties, and on brittleness of hair and nails.

  9. Cosmology in nonlinear multidimensional gravity and the Casimir effect

    Science.gov (United States)

    Bolokhov, S. V.; Bronnikov, K. A.

    2017-01-01

    We study the possible cosmological models in Kaluza-Klein-type multidimensional gravity with a curvature-nonlinear Lagrangian and a spherical extra space, taking into account the Casimir energy. First, we find a minimum of the effective potential of extra dimensions, leading to a physically reasonable value of the effective cosmological constant in our 4D space-time. In this model, the huge Casimir energy density is compensated by a fine-tuned contribution of the curvature-nonlinear terms in the original action. Second, we present a viable model with slowly evolving extra dimensions and power-law inflation in our space-time. In both models, the results formulated in Einstein and Jordan frames are compared.

  10. Pred-Skin: A Fast and Reliable Web Application to Assess Skin Sensitization Effect of Chemicals.

    Science.gov (United States)

    Braga, Rodolpho C; Alves, Vinicius M; Muratov, Eugene N; Strickland, Judy; Kleinstreuer, Nicole; Trospsha, Alexander; Andrade, Carolina Horta

    2017-05-22

    Chemically induced skin sensitization is a complex immunological disease with a profound impact on quality of life and working ability. Despite some progress in developing alternative methods for assessing the skin sensitization potential of chemical substances, there is no in vitro test that correlates well with human data. Computational QSAR models provide a rapid screening approach and contribute valuable information for the assessment of chemical toxicity. We describe the development of a freely accessible web-based and mobile application for the identification of potential skin sensitizers. The application is based on previously developed binary QSAR models of skin sensitization potential from human (109 compounds) and murine local lymph node assay (LLNA, 515 compounds) data with good external correct classification rate (0.70-0.81 and 0.72-0.84, respectively). We also included a multiclass skin sensitization potency model based on LLNA data (accuracy ranging between 0.73 and 0.76). When a user evaluates a compound in the web app, the outputs are (i) binary predictions of human and murine skin sensitization potential; (ii) multiclass prediction of murine skin sensitization; and (iii) probability maps illustrating the predicted contribution of chemical fragments. The app is the first tool available that incorporates quantitative structure-activity relationship (QSAR) models based on human data as well as multiclass models for LLNA. The Pred-Skin web app version 1.0 is freely available for the web, iOS, and Android (in development) at the LabMol web portal ( http://labmol.com.br/predskin/ ), in the Apple Store, and on Google Play, respectively. We will continuously update the app as new skin sensitization data and respective models become available.

  11. New approximation for the effective energy of nonlinear conducting composites

    Science.gov (United States)

    Gibiansky, Leonid; Torquato, Salvatore

    1998-07-01

    Approximations for the effective energy and, thus, effective conductivity of nonlinear, isotropic conducting dispersions are developed. This is accomplished by using the Ponte Castaneda variational principles [Philos. Trans. R. Soc. London Ser. A 340, 1321 (1992)] and the Torquato approximation [J. Appl. Phys. 58, 3790 (1985)] of the effective conductivity of corresponding linear composites. The results are obtained for dispersions with superconducting or insulating inclusions, and, more generally, for phases with a power-law energy. It is shown that the new approximations lie within the best available rigorous upper and lower bounds on the effective energy.

  12. Nonlinear effect induced in thermally poled glass waveguides

    Institute of Scientific and Technical Information of China (English)

    REN Yi-tao

    2006-01-01

    Thermally poled germanium-doped channel waveguides are presented. Multilayer waveguides containing a silicon oxynitride layer were used as charge trapper in this investigation on the effect of the internal field inside the waveguide. Compared to waveguides without the trapping layer, experimental results showed that the induced linear electro-optic (EO) coefficient increases about 20% after poling, suggesting strongly that the internal field is relatively enhanced, and showed it is a promising means for improving nonlinearity by poling in waveguides.

  13. INFLUENCE ANALYSIS ON EXPONENTIAL NONLINEAR MODELS WITH RANDOM EFFECTS

    Institute of Scientific and Technical Information of China (English)

    宗序平; 赵俊; 王海斌; 韦博成

    2003-01-01

    This paper presents a unified diagnostic method for exponential nonlinear models with random effects based upon the joint likelihood given by Robinson in 1991.The authors show that the case deletion model is equivalent to mean shift outlier model.From this point of view,several diagnostic measures,such as Cook distance,score statistics are derived.The local influence measure of Cook is also presented.Numerical example illustrates that our method is available.

  14. INFLUENCE ANALYSIS IN NONLINEAR MODELS WITH RANDOM EFFECTS

    Institute of Scientific and Technical Information of China (English)

    WeiBocheng; ZhongXuping

    2001-01-01

    Abstract. In this paper,a unified diagnostic method for the nonlinear models with random ef-fects based upon the joint likelihood given by Robinson in 1991 is presented. It is shown that thecase deletion model is equivalent to the mean shift outlier model. From this point of view ,sever-al diagnostic measures, such as Cook distance, score statistics are derived. The local influencemeasure of Cook is also presented. A numerical example illustrates that the method is avail-able

  15. Analysis of effect of different construction methods of piles on the end effect on skin friction of piles

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hongbo; CHEN Zhuchang

    2007-01-01

    Based on the comparative analysis of end effect on skin friction of displacement-pile (driven pile),the end effect on skin friction of bored pile is studied.The end effect on skin friction between driven pile and bored pile is different and the end effect on skin friction of bored pile is reduce of skin friction in the soil layer adjacent to the pile end.The degradation degree of skin friction is deduced with the increase of the distance from pile end.The concept of additional mud cake formed by the effect of cushion at the bottom of borehole during pouring concrete is introduced to explain the mechanism of end effect on skin friction of the bored pile.The test results of post-grouting piles indicate that the post-grouting technique is an effective way to improve the end effect on skin friction of bored pile.

  16. Effects of disinfectants and detergents on skin irritation.

    Science.gov (United States)

    Slotosch, Caroline M; Kampf, Günter; Löffler, Harald

    2007-10-01

    We investigated the biological response of regular human skin to alcohol-based disinfectants and detergents in a repetitive test design. Using non-invasive diagnostic tools such as transepidermal water loss, laser-Doppler flowmetry and corneometry, we quantified the irritative effects of a propanol-based hand disinfectant (Sterillium), its propanol mixture (2-propanol 45% w/w and 1-propanol 30% w/w), sodium lauryl sulfate (SLS) 0.5% and distilled water. The substances were applied in a 2-D patch test in a repetitive occlusive test design to the back. Additionally, we performed a wash test on the forearms that was supposed to mimic the skin affection in the normal daily routine of health care workers. In this controlled half-side test design, we included the single application of the hand rub, SLS 0.5% and water as well as a tandem application of the same substances. Patch test and wash test showed similar results. The alcohol-based test preparations showed minimal irritation rather comparable to the application of water. However, the detergent SLS produced stronger barrier disruption, erythema and dryness than the alcohol-based preparations. There was no additional irritation at the combined use of SLS and disinfectants. By contrary, there was even a decrease in barrier disruption and erythema induced by the tandem application of SLS followed by alcohol-based disinfection compared with the use of SLS alone. These findings show a less irritant effect of alcohol-based disinfectants on the skin than detergents. Our study shows that there is no summation of irritating effects of a common detergent and propanol and that the combination of washing and disinfection has a rather protective aspect compared with washing alone.

  17. Controlling ultrafast currents by the nonlinear photogalvanic effect

    Science.gov (United States)

    Wachter, Georg; Sato, Shunsuke A.; Floss, Isabella; Lemell, Christoph; Tong, Xiao-Min; Yabana, Kazuhiro; Burgdörfer, Joachim

    2015-12-01

    We investigate the effect of broken inversion symmetry on the generation and control of ultrafast currents in a transparent dielectric (SiO2) by strong femtosecond optical laser pulses. Ab initio simulations based on time-dependent density functional theory predict ultrafast direct currents that can be viewed as a nonlinear photogalvanic effect. Most surprisingly, the direction of the current undergoes a sudden reversal above a critical threshold value of laser intensity of about {I}{{c}}˜ 3× {10}13 W cm-2. We trace this switching to the transition from nonlinear polarisation currents to the tunnelling excitation regime. The latter is found to be sensitive to the relative orientation between laser polarisation and chemical bonds. We demonstrate control of the ultrafast currents by the time delay between two laser pulses. While two temporally separated laser pulses lead to currents along one direction their temporal overlap can reverse the current. We find the ultrafast current control by the nonlinear photogalvanic effect to be remarkably robust and insensitive to the laser-pulse shape and the carrier-envelope phase.

  18. Protective effect of gelatin and gelatin hydrolysate from salmon skin on UV irradiation-induced photoaging of mice skin

    Science.gov (United States)

    Chen, Tiejun; Hou, Hu; Lu, Jiaohan; Zhang, Kai; Li, Bafang

    2016-08-01

    The objective of this study was to investigate the effect of gelatin (SG) isolated from salmon skin and its hydrolysate (SGH) on photoaging skin, and the mechanism responsible for anti-photoaging. The average molecular weights of SG and SGH were 65 kDa and 873 Da, respectively. The amino acid compositions of SG and SGH were similar. Both of them were abundant in hydrophobic amino acids. Twenty-five peptides were identified from SGH. SG and SGH could improve UV irradiation-induced pathological changes of macroscopical tissue texture and skin morphology. Hydroxyproline content is an indicator of matrix collagen content, SG and SGH could inhibit the decrease of hydroxyproline content in photoaging skin in a dose dependent manner. In addition, SG and SGH could alleviate UV irradiation-induced oxidative damages to skin by increasing the activities of total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), increasing the content of glutathione (GSH) and decreasing the content of malonaldehyde (MDA). Moreover, SG and SGH could enhance immune regulation system by increasing the thymus index. Thus, the anti-photoaging mechanisms of SG and SGH were by inhibiting the depletion of antioxidant defense components, involving in the synthesis of collagen and enhancing the function of immune system. Besides, SGH showed a better result in protecting skin from photoaging than SG.

  19. Dynamic hysteresis modeling including skin effect using diffusion equation model

    Science.gov (United States)

    Hamada, Souad; Louai, Fatima Zohra; Nait-Said, Nasreddine; Benabou, Abdelkader

    2016-07-01

    An improved dynamic hysteresis model is proposed for the prediction of hysteresis loop of electrical steel up to mean frequencies, taking into account the skin effect. In previous works, the analytical solution of the diffusion equation for low frequency (DELF) was coupled with the inverse static Jiles-Atherton (JA) model in order to represent the hysteresis behavior for a lamination. In the present paper, this approach is improved to ensure the reproducibility of measured hysteresis loops at mean frequency. The results of simulation are compared with the experimental ones. The selected results for frequencies 50 Hz, 100 Hz, 200 Hz and 400 Hz are presented and discussed.

  20. Dynamic hysteresis modeling including skin effect using diffusion equation model

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Souad, E-mail: souadhamada@yahoo.fr [LSP-IE: Research Laboratory, Electrical Engineering Department, University of Batna, 05000 Batna (Algeria); Louai, Fatima Zohra, E-mail: fz_louai@yahoo.com [LSP-IE: Research Laboratory, Electrical Engineering Department, University of Batna, 05000 Batna (Algeria); Nait-Said, Nasreddine, E-mail: n_naitsaid@yahoo.com [LSP-IE: Research Laboratory, Electrical Engineering Department, University of Batna, 05000 Batna (Algeria); Benabou, Abdelkader, E-mail: Abdelkader.Benabou@univ-lille1.fr [L2EP, Université de Lille1, 59655 Villeneuve d’Ascq (France)

    2016-07-15

    An improved dynamic hysteresis model is proposed for the prediction of hysteresis loop of electrical steel up to mean frequencies, taking into account the skin effect. In previous works, the analytical solution of the diffusion equation for low frequency (DELF) was coupled with the inverse static Jiles-Atherton (JA) model in order to represent the hysteresis behavior for a lamination. In the present paper, this approach is improved to ensure the reproducibility of measured hysteresis loops at mean frequency. The results of simulation are compared with the experimental ones. The selected results for frequencies 50 Hz, 100 Hz, 200 Hz and 400 Hz are presented and discussed.

  1. Investigation on the effect of developed product and new food for radiation-induced skin damage

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Ho; Kim, Jong Chun; Bae, Chun Sik; Kim, Se Ra; Lee, Hae Jun; Bang, Dae Won; Lee, Jin Hee; Kim, Joong Sun; Ki, Sun Ah; Song, Myung Seop [Chonnam National University, Gwangju (Korea, Republic of)

    2007-07-15

    In vivo evaluation of the developed pilot product on the skin protection against UV irradiation and screening of new candidate materials. Project Results are Establishment of experimental methods for 3 morphological indices of UV-induced skin damages -Establishment of experimental methods for whitening effect evaluation -Evaluation of HemoHIM administration on the skin damage indices -Evaluation of HemoHIM skin application on the skin damage indices -Evaluation of HemoTonic administration on the skin damage indices -Evaluation of HemoTonic skin application on the skin damage indices -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 1 -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 2 -Evaluation of HemoHIM on the antiinflamatory effects in the inflammation stage 3 -Evaluation of HemoHIM on the antiinflamatory effects in the TNBS-induced colitis -Evaluation of HemoHIM on the anti-wrinkle effects in the skin -Evaluation of HemoHIM on the protective effects on the skin tissue (epidermal thickening, dermal cellularity, dermal cyst) -Evaluation of HemoHIM on the protective effects on the skin tumor development

  2. Effects of Dermal Multipotent Cell Transplantation on Skin Wound Healing

    Institute of Scientific and Technical Information of China (English)

    ShiChunmeng; ChengTianmin; SuYongping; RanXinze; MaiYue; QuJifu; LouShufen; XuHui; LuoChengji

    2005-01-01

    There is increasing evidence that dermis contains adult multipotent stem cells. To investigate the effects of dermis-derived multipotent cells on wound healing, we transplanted a clonal population of dermis-derived multipotent cells (termed as DMCs) by topical and systemic application into the skin wound of rats with simple wounds and rats with combined wound and radiation injury. Our results suggest that both topical and systemic transplantation of DMCs accelerate the healing process in rats with a simple wound; the promoting effect by topical transplantation occurs earlier than systemic transplantation. However, systemic transplantation of DMCs promotes the healing process in irradiated rats, while topical transplantation of DMCs fails. Further studies on the mechanisms of DMCs to promote wound healing indicate that the supernatant of DMCs could promote the proliferation of fibroblasts and epidermal cells; DMCs expressed transcripts of a serics of cytokincs and cxtraccllular matrix molecules, including VEGF, PDGF, HGF, TGF-β, ICAM-1, VCAM-1, and Fibronectin, which were closely related to the wound healing by DNA microarray analysis. The implanted DMCs can engraft into recipient skin wounded tissues after transplantation by the FISH analysis with Y-chromosome-specific probe. Systemic transplantation of DMCs also promotes the recovery of peripheral white blood cells in irradiated rats. These results demonstrate the different effects of DMCs on wound healing in nonirradiated and irradiated rats and illustrate the importance of optimizing wound healing via the topical or systemic transplantation of stem cells.

  3. Non-linear effects for cylindrical gravitational two-soliton

    CERN Document Server

    Tomizawa, Shinya

    2015-01-01

    Using a cylindrical soliton solution to the four-dimensional vacuum Einstein equation, we study non-linear effects of gravitational waves such as Faraday rotation and time shift phenomenon. In the previous work, we analyzed the single-soliton solution constructed by the Pomeransky's improved inverse scattering method. In this work, we construct a new two-soliton solution with complex conjugate poles, by which we can avoid light-cone singularities unavoidable in a single soliton case. In particular, we compute amplitudes of such non-linear gravitational waves and time-dependence of the polarizations. Furthermore, we consider the time shift phenomenon for soliton waves, which means that a wave packet can propagate at slower velocity than light.

  4. Nonlinear thermokinetic phenomena due to the Seebeck effect.

    Science.gov (United States)

    Sugioka, Hideyuki

    2014-07-22

    We propose a novel mechanism to produce nonlinear thermokinetic vortex flows around a circular cylinder with ideally high thermal conductivity in an electrolyte. That is, the nonlinear thermokinetic slip velocity, which is proportional to the square of the temperature gradient [∇(T)0(2)], is derived based on the electrolyte Seebeck effect, heat conduction equation, and Helmholtz–Smoluchowski formula. Different from conventional linear thermokinetic theory, our theory predicts that the inversion of the temperature gradient does not change the direction of the thermokinetic flows and thus a Janus particle using this phenomenon can move to the both hotter and colder regions in a temperature gradient field by changing the direction of its dielectric end. Our findings bridge the gap between the electro- and thermo-kinetic phenomena and provide an integrated physical viewpoint for the interface science.

  5. Anharmonic effects in simple physical models: introducing undergraduates to nonlinearity

    Science.gov (United States)

    Christian, J. M.

    2017-09-01

    Given the pervasive character of nonlinearity throughout the physical universe, a case is made for introducing undergraduate students to its consequences and signatures earlier rather than later. The dynamics of two well-known systems—a spring and a pendulum—are reviewed when the standard textbook linearising assumptions are relaxed. Some qualitative effects of nonlinearity can be anticipated from symmetry (e.g., inspection of potential energy functions), and further physical insight gained by applying a simple successive-approximation method that might be taught in parallel with courses on classical mechanics, ordinary differential equations, and computational physics. We conclude with a survey of how these ideas have been deployed on programmes at a UK university.

  6. Doppler effect of nonlinear waves and superspirals in oscillatory media.

    Science.gov (United States)

    Brusch, Lutz; Torcini, Alessandro; Bär, Markus

    2003-09-01

    Nonlinear waves emitted from a moving source are studied. A meandering spiral in a reaction-diffusion medium provides an example in which waves originate from a source exhibiting a back-and-forth movement in a radial direction. The periodic motion of the source induces a Doppler effect that causes a modulation in wavelength and amplitude of the waves ("superspiral"). Using direct simulations as well as numerical nonlinear analysis within the complex Ginzburg-Landau equation, we show that waves subject to a convective Eckhaus instability can exhibit monotonic growth or decay as well as saturation of these modulations depending on the perturbation frequency. Our findings elucidate recent experimental observations concerning superspirals and their decay to spatiotemporal chaos.

  7. The positive effect of skin transpiration in peach fruit growth.

    Science.gov (United States)

    Morandi, Brunella; Manfrini, Luigi; Losciale, Pasquale; Zibordi, Marco; Corelli-Grappadelli, Luca

    2010-09-01

    The effect of fruit transpiration on the mechanisms driving peach (Prunus persica (L.) Batsch) daily growth was investigated. In peach, fruit water losses increase during the season and might play a key role in determining fruit growth. Skin transpiration was reduced during the cell expansion stage by enclosing fruit in plastic bags fitted with holes. In the first year, diameter changes of bagged and control fruit were precisely monitored for 15 days, and percentage dry matter and soluble solids content were determined during the experiment and at harvest. In the second year, midday fruit water potential, daily patterns of fruit growth and of vascular and transpiration flows were monitored. Bagging reduced fruit daily growth on some days, and negatively affected both fruit dry matter percentage and soluble solids content. Fruit transpiration rate was reduced during the midday hours, thus increasing midday fruit water potential and lowering xylem inflows. In accordance with the Münch hypothesis on traslocation, these conditions likely decreased the necessary gradient needed for the transport of phloem sap to sink organs, as in the afternoon, bagged fruit showed lower phloem inflows. These data suggest that skin transpiration in peach has a positive effect on fruit growth, as it enhances fruit phloem import.

  8. Effects of Ginsenoside Rb1 on Skin Changes

    Directory of Open Access Journals (Sweden)

    Yoshiyuki Kimura

    2012-01-01

    Full Text Available Ginseng roots (Panax ginseng CA Meyer have been used traditionally for the treatment, especially prevention, of various diseases in China, Korea, and Japan. Both experimental and clinical studies suggest ginseng roots to have pharmacological effects in patients with life-style-related diseases such as non-insulin-dependent diabetic mellitus, atherosclerosis, hyperlipidemia, and hypertension. The topical use of ginseng roots to treat skin complaints including atopic suppurative dermatitis, wounds, and inflammation is also described in ancient Chinese texts; however, there have been relatively few studies in this area. In the present paper, we describe introduce the biological and pharmacological effects of ginsenoside Rb1 isolated from Red ginseng roots on skin damage caused by burn-wounds using male Balb/c mice (in vivo and by ultraviolet B irradiation using male C57BL/6J and albino hairless (HR-1 mice (in vivo. Furthermore, to clarify the mechanisms behind these pharmacological actions, human primary keratinocytes and the human keratinocyte cell line HaCaT were used in experiments in vitro.

  9. Improved treatment of radiation effects on the skin

    Energy Technology Data Exchange (ETDEWEB)

    Wandl, E.O.; Kaercher, K.H.; Wandl-Hainberger, I.

    1985-04-29

    The treatment concept developed by K.H. Kaercher was extended by a therapy using Elasten S cream. In the course of a highvoltage therapy using fast electrons or cobalt-60, interesting aspects in the treatment and progression of the radiation reactions of the skin were established. The dermato-therapeutic principles layed down by K.H. Kaercher with the treatment palette used hitherto, have without doubt invariably proven their value. The exclusive powder treatment, however, may be made more practical by application of the new treatment cream in accordance with the intervals in radiation treatment or as a basic treatment towards the end of therapy. Furthermore it is ideally suited for the care and after-treatment of skin, strained by radiation. It reduces considerably the remaining visible radiation reactions. The treatment with powder and emulsion has for more than 10 years proven effective. After the excellent results of the new cream during radiation treatment, additional positive effects are expected in a long-term trial which will be reported on separately.

  10. The Photoprotective Effect of S-Methylmethionine Sulfonium in Skin

    Directory of Open Access Journals (Sweden)

    Won-Serk Kim

    2015-07-01

    Full Text Available S-Methylmethionine sulfonium (SMMS was reported to have wound-healing effects; we therefore have investigated the photoprotective effect of SMMS in the present study. SMMS increased the viability of keratinocyte progenitor cells (KPCs and human dermal fibroblasts (hDFs following ultraviolet B (UVB irradiation, and reduced the UVB-induced apoptosis in these cells. SMMS increased the phosphorylation of extracellular signal-regulated kinases (ERK, and the inhibitor of the mitogen-activated protein kinase pathway significantly decreased the SMMS-induced viability of KPCs and hDFs. In addition, SMMS attenuated the UVB-induced reactive oxygen species (ROS generation in KPCs and hDFs. SMMS induced the collagen synthesis and reduced the matrix metalloproteinase-1 expression in UVB-irradiated hDFs. In animal studies, application of 5% and 10% SMMS before and after UVB-irradiation significantly decreased the UVB-induced erythema index and depletion of Langerhans cells. In summary, SMMS protects KPCs and hDFs from UVB irradiation, and reduces UVB-induced skin erythema and immune suppression. Therefore, SMMS can be used as a cosmetic raw material, and protect skin from UVB.

  11. Negative and nonlinear magnetoresistance effect in silicon strip

    CERN Document Server

    Wang, Fangcong; Guo, Hui; Fan, Xiaolong; Li, Zhankui

    2016-01-01

    Both negative magnetoresistance and nonlinear magnetoresisitance were observed in silicon strip nuclear radiation detector in room temperature if we applied high magnetic field intensity in different direction. This result is different with former report. We believe this is the result of coaction of high electric field (Gunn effect) and high magnetic field, or because of the variation of number of carriers and the carriers mobility. The weak localization and Landau energy levels also affect the magnetoresistance. Different crystal orientations have different energy band structures. Complex band structures lead complex carriers mobility plus Landau energy levels. So the magnetoresisitance effect is anisotropy.

  12. Power-transfer effects in monomode optical nonlinear waveguiding structures.

    Science.gov (United States)

    Jakubczyk, Z; Jerominek, H; Patela, S; Tremblay, R; Delisle, C

    1987-09-01

    We describe power-transfer effects, over a certain threshold, among constituents of planar waveguiding structures consisting of an optical linear layer deposited onto a nonlinear substrate (CdS(x)Se(1-x)-doped glass). Proper selection of the thickness of the linear waveguiding film and the refractive index of the linear cladding allows one to obtain optical transistor action and to construct all-optical AND, OR, NOT, and XOR logic gates. The effects appear for the TE(0) guided mode.

  13. Modeling and study of nonlinear effects in electrodynamic shakers

    Science.gov (United States)

    Saraswat, Abhishek; Tiwari, Nachiketa

    2017-02-01

    An electrodynamic shaker is inherently a nonlinear electro-mechanical system. In this work, we have developed a lumped parameter model for the entire electromechanical system, developed an approach to non-destructively determine these parameters, and predict the nonlinear response of the shaker. This predicted response has been validated using experimental data. Through such an approach, we have been able to accurately predict the resulting distortions in the response of the shaker and other nonlinear effects like DC offset in the displacement response. Our approach offers a key advantage vis-à-vis other approaches which rely on techniques involving Volterra Series expansions or techniques based on blackbox models like neural networks, which is that in our approach, apart from predicting the response of the shaker, the model parameters obtained have a physical significance and changes in the parameters can be directly mapped to modification in key design parameters of the shaker. The proposed approach is also advantageous in one more way: it requires measurement of only four parameters, voltage, current, displacement and acceleration for estimating shaker model parameters non-destructively. The proposed model can be used for the design of linearization controllers, prototype testing and simulation of new shaker designs as well as for performance prediction of shakers under testing conditions.

  14. Effects of Plasma Shaping on Nonlinear Gyrokinetic Turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Belli, E. A. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Hammett, G. W. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Dorland, W. [Univ. of Maryland, College Park, MD (United States)

    2008-08-01

    The effects of flux surface shape on the gyrokinetic stability and transport of tokamak plasmas are studied using the GS2 code [M. Kotschenreuther, G. Rewoldt, and W.M. Tang, Comput. Phys. Commun. 88, 128 (1995); W. Dorland, F. Jenko, M. Kotschenreuther, and B.N. Rogers, Phys. Rev. Lett. 85, 5579 (2000)]. Studies of the scaling of nonlinear turbulence with shaping parameters are performed using analytic equilibria based on interpolations of representative shapes of the Joint European Torus (JET) [P.H. Rebut and B.E. Keen, Fusion Technol. 11, 13 (1987)]. High shaping is found to be a stabilizing influence on both the linear ion-temperature-gradient (ITG) instability and the nonlinear ITG turbulence. For the parameter regime studied here, a scaling of the heat flux with elongation of χ ~ κ-1.5 or κ-2.0, depending on the triangularity, is observed at fixed average temperature gradient. While this is not as strong as empirical elongation scalings, it is also found that high shaping results in a larger Dimits upshift of the nonlinear critical temperature gradient due to an enhancement of the Rosenbluth-Hinton residual zonal flows.

  15. Wave-packet dynamics in one-dimensional nonlinear Schroedinger lattices: local vs. nonlocal nonlinear effects

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ba Phi [Central University of Construction, Tuy Hoa (Viet Nam); Kim, Ki Hong [Ajou University, Suwon (Korea, Republic of)

    2014-02-15

    We study numerically the dynamics of an initially localized wave packet in one-dimensional nonlinear Schroedinger lattices with both local and nonlocal nonlinearities. Using the discrete nonlinear Schroedinger equation generalized by including a nonlocal nonlinear term, we calculate four different physical quantities as a function of time, which are the return probability to the initial excitation site, the participation number, the root-mean-square displacement from the excitation site and the spatial probability distribution. We investigate the influence of the nonlocal nonlinearity on the delocalization to self-trapping transition induced by the local nonlinearity. In the non-self-trapping region, we find that the nonlocal nonlinearity compresses the soliton width and slows down the spreading of the wave packet. In the vicinity of the delocalization to self-trapping transition point and inside the self-trapping region, we find that a new kind of self-trapping phenomenon, which we call partial self-trapping, takes place when the nonlocal nonlinearity is sufficiently strong.

  16. Modulation of skin pigmentation by the tetrapeptide PKEK: in vitro and in vivo evidence for skin whitening effects.

    Science.gov (United States)

    Marini, Alessandra; Farwick, Mike; Grether-Beck, Susanne; Brenden, Heidi; Felsner, Ingo; Jaenicke, Thomas; Weber, Monika; Schild, Jennifer; Maczkiewitz, Ursula; Köhler, Tim; Bonfigli, Adriana; Pagani, Valerie; Krutmann, Jean

    2012-02-01

    Uneven skin pigmentation is a significant cosmetic concern, and the identification of topically applicable molecules to address this issue is of general interest. We report that the tetrapeptide PKEK (Pro-Lys-Glu-Lys) can exert skin whitening effects based on one in vitro and four double-blinded vehicle-controlled in vivo studies. (i) Treatment of human keratinocytes with PKEK significantly reduced UVB-stimulated mRNA expression of interleukin (IL)-6, IL-8 and TNF-α and, most importantly, proopiomelanocorticotropin (POMC), i.e. a gene encoding the pigmentation-inducing soluble mediator α- (α-MSH). (ii) PKEK treatment significantly inhibited UVB-induced upregulation of genes encoding for IL-1α, IL-6, IL-8, TNF-α as well as POMC and tyrosinase in 10 healthy volunteers pretreated with PKEK for 4 weeks once daily. (iii) In a study enrolling 39 Caucasian women, facial pigment spots significantly faded after 6 weeks when PKEK was combined with the skin whitener sodium ascorbyl phosphate (SAP), whereas PKEK or SAP alone led to less pronounced fading of the pigment spots. (iv) Addition of PKEK enhanced the skin whitening potency of a SAP-containing preparation if applied for 8 weeks to the back of hands of 19 Caucasians. (v) 27 Japanese women were treated on their faces twice daily with an SAP only or a PKEK+SAP-containing formulation for 8 weeks. Application of PKEK+SAP significantly reduced skin pigmentation by 26% and by 18% according to SCINEXA score. We demonstrate that PKEK has the capacity to reduce UVB-induced skin pigmentation and may be suited to serve as a skin tone-modulating agent in cosmetic products.

  17. Effects of erythropoietin in skin wound healing are dose related.

    Science.gov (United States)

    Sorg, Heiko; Krueger, Christian; Schulz, Torsten; Menger, Michael D; Schmitz, Frank; Vollmar, Brigitte

    2009-09-01

    The hematopoietic growth factor erythropoietin (EPO) attracts attention due to its all-tissue-protective pleiotropic properties. We studied the effect of EPO on dermal regeneration using intravital microscopy in a model of full dermal thickness wounds in the skin-fold chamber of hairless mice. Animals received repetitive low doses or high doses of EPO (RLD-EPO or RHD-EPO) or a single high dose of EPO (SHD-EPO). SHD-EPO accelerated wound epithelialization, reduced wound cellularity, and induced maturation of newly formed microvascular networks. In contrast, RHD-EPO impaired the healing process, as indicated by delayed epithelialization, high wound cellularity, and lack of maturation of microvascular networks. Also, RHD-EPO caused an excessive erythrocyte mass and rheological malfunction, further deteriorating vessel and tissue maturation. Moreover, RHD-EPO altered fibroblast and keratinocyte migration in vitro, while both cell types exposed to RLD-EPO, and, in particular, to SHD-EPO showed accelerated wound scratch closure. In summary, our data show that a single application of a high dose of EPO accelerates and improves skin wound healing.

  18. IMMUNOMODULATORY EFFECTS OF VITAMIN D ON SKIN INFLAMMATION.

    Science.gov (United States)

    Toniato, E; Spinas, E; Saggini, A; Kritas, S K; Caraffa, A; Antinolfi, P; Saggini, R; Pandolfi, F; Conti, P

    2015-01-01

    Vitamin D has a major role in calcium absorption and maintenance of healthy bones. Vitamin D is also involved in cancer, cardiovascular system, allergic diseases, immune regulation and immune disor¬ders. Irradiation of food as well as animals produces vitamin D and more than 90% of previtamin D3 synthesis in the skin occurs in the epidermis. Vitamin D receptor has been found in many cells including T and B lymphocytes, macrophages, mast cells, NK cells and Tregs, and it selectively binds with high affinity to its ligand. Vitamin D binds its receptor VDR, resulting in transcription of a number of genes playing a role in inhibition of MAPK. Its effect may be also mediated by the direct activation of PKC. Vitamin D has the ability to suppress inflammatory cytokines such as TNF, IL-1, IFN-gamma and IL-2; while it increases the generation of anti-inflammatory cytokines IL-4 and IL-10. In B cells, vitamin D3 have also been shown to suppress IgE antibody class switch partly through the inhibition of NF-kB. Here we discuss the relationship between vitamin D, immunity and skin disorders.

  19. Evaluating the Effect of Mother – Baby Skin- to- Skin Care on Neonatal Outcomes in Preterm Infants

    Directory of Open Access Journals (Sweden)

    M Kalhor

    2016-08-01

    Full Text Available Introduction: Involving the parents in caring of premature newborns is one of the best and effective manners for preventing the hospitalization of premature newborns. The present study aimed to evaluate the effect of mother – baby skin- to- skin care on neonatal outcomes in preterm infants, in Kosar hospital. Methods: This was a descriptive comparative study conducted on 400 nulliparous women with premature infants admitted to neonatal intensive care unit of Kosar hospital during April 2012 and March 2015. Sampling was performed via convenience sampling. Sample population divided into two groups, one of them 200, the kangaroo care and non- care groups. The data were obtained by a researcher prepared check list, including mother’s demographic characteristics and neonatal outcomes. Both descriptive and statistical analysis methods were applied. For analyzing the data, chi-square test, t-test, and logistic regression tests was applied (P 0.05. In the intervention group, the relationship between maternal variables and neonatal outcome was significant (P <0.05. Conclusion: Mother – baby skin- to- skin care has a positive effect on neonatal outcomes. Thus, supporting and awareness of premature infants’ mothers in order to implement this type of care can reduce the neonatal complications. Moreover, it is effective in decreasing the treatment costs.

  20. Current-induced nonlinear magnetoelectric effects in strontium hexaferrite

    Science.gov (United States)

    Zavislyak, I. V.; Popov, M. A.; Srinivasan, G.

    2016-12-01

    We report on the observation of nonlinear magnetoelectric effects at room temperature due to a dc current in the ferrimagnetic M -type strontium hexaferrite platelets. Utilizing microwave measurement techniques and data on the shift in magnetic mode frequencies, it was found that a dc current along the hexagonal c axis resulted in a significant decrease in the saturation magnetization and an increase in the uniaxial magnetocrystalline anisotropy field. These changes in the magnetic order parameters were directly proportional to the square of applied electric field and were found to be much higher than variations due to Joule heating. A phenomenological theory that takes into account the current-induced magnetobielectric (MBE) effects is proposed. Expressions for coupling coefficients for MBE effects have been obtained and have been calculated from the variations in magnetic order parameters. The electric field E (or current) tuning of the magnetic modes in Sr M reported here is orders of magnitude stronger than strain mediated E tuning of magnetic resonance in hexaferrite-ferroelectric composites. The nonlinear magnetoelectric effects in hexaferrite, therefore, open up an avenue for the realization of E -tunable broadband microwave and millimeter wave ferrite signal processing devices such as resonators and filters.

  1. Effect of olive and sunflower seed oil on the adult skin barrier: implications for neonatal skin care.

    Science.gov (United States)

    Danby, Simon G; AlEnezi, Tareq; Sultan, Amani; Lavender, Tina; Chittock, John; Brown, Kirsty; Cork, Michael J

    2013-01-01

    Natural oils are advocated and used throughout the world as part of neonatal skin care, but there is an absence of evidence to support this practice. The goal of the current study was to ascertain the effect of olive oil and sunflower seed oil on the biophysical properties of the skin. Nineteen adult volunteers with and without a history of atopic dermatitis were recruited into two randomized forearm-controlled mechanistic studies. The first cohort applied six drops of olive oil to one forearm twice daily for 5 weeks. The second cohort applied six drops of olive oil to one forearm and six drops of sunflower seed oil to the other twice daily for 4 weeks. The effect of the treatments was evaluated by determining stratum corneum integrity and cohesion, intercorneocyte cohesion, moisturization, skin-surface pH, and erythema. Topical application of olive oil for 4 weeks caused a significant reduction in stratum corneum integrity and induced mild erythema in volunteers with and without a history of atopic dermatitis. Sunflower seed oil preserved stratum corneum integrity, did not cause erythema, and improved hydration in the same volunteers. In contrast to sunflower seed oil, topical treatment with olive oil significantly damages the skin barrier, and therefore has the potential to promote the development of, and exacerbate existing, atopic dermatitis. The use of olive oil for the treatment of dry skin and infant massage should therefore be discouraged. These findings challenge the unfounded belief that all natural oils are beneficial for the skin and highlight the need for further research.

  2. Effects of Father-Neonate Skin-to-Skin Contact on Attachment: A Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Er-Mei Chen

    2017-01-01

    Full Text Available This study examines how skin-to-skin contact between father and newborn affects the attachment relationship. A randomized controlled trial was conducted at a regional teaching hospital and a maternity clinic in northern Taiwan. The study recruited 83 first-time fathers aged 20 years or older. By block randomization, participants were allocated to an experimental (n=41 or a control (n=42 group. With the exception of skin-to-skin contact (SSC, participants from each group received the same standard care. Both groups also received an Early Childcare for Fathers nursing pamphlet. During the first three days postpartum, the intervention group members were provided a daily SSC intervention with their respective infants. Each intervention session lasted at least 15 minutes in length. The outcome measure was the Father-Child Attachment Scale (FCAS. After adjusting for demographic data, the changes to the mean FCAS were found to be significantly higher in the intervention group than in the control group. We recommend that nurses and midwives use instructional leaflets and demonstrations during postpartum hospitalization, encouraging new fathers to take an active role in caring for their newborn in order to enhance father-neonate interactions and establish parental confidence. This trial is registered with clinical trial registration number NCT02886767.

  3. Effects of Father-Neonate Skin-to-Skin Contact on Attachment: A Randomized Controlled Trial

    Science.gov (United States)

    Chen, Er-Mei; Liu, Chieh-Yu

    2017-01-01

    This study examines how skin-to-skin contact between father and newborn affects the attachment relationship. A randomized controlled trial was conducted at a regional teaching hospital and a maternity clinic in northern Taiwan. The study recruited 83 first-time fathers aged 20 years or older. By block randomization, participants were allocated to an experimental (n = 41) or a control (n = 42) group. With the exception of skin-to-skin contact (SSC), participants from each group received the same standard care. Both groups also received an Early Childcare for Fathers nursing pamphlet. During the first three days postpartum, the intervention group members were provided a daily SSC intervention with their respective infants. Each intervention session lasted at least 15 minutes in length. The outcome measure was the Father-Child Attachment Scale (FCAS). After adjusting for demographic data, the changes to the mean FCAS were found to be significantly higher in the intervention group than in the control group. We recommend that nurses and midwives use instructional leaflets and demonstrations during postpartum hospitalization, encouraging new fathers to take an active role in caring for their newborn in order to enhance father-neonate interactions and establish parental confidence. This trial is registered with clinical trial registration number NCT02886767. PMID:28194281

  4. Nonlinear Magnetoimpedance Effect in FeCoNi Ferromagnetic Tubes

    Institute of Scientific and Technical Information of China (English)

    G. V. Kurlyandskaya; H. Yakabchuk; E. Kisker; N. G. Bebenin; H. García-Miquel; M. Vázquez; V. O. Vas′kovskiy

    2001-01-01

    The very high (up to 820% of the magnetoimpedance ratio) and sensitive nonlinear giant magnetoimpedance effect has been studied in the FeCo1Ni magnetic tubes electroplated onto Cu(3%)Be nonmagnetic wirefor frequencies from 1-10MHz. Special annealing was carried out in order to induce the magnetic anisotropy. The high harmonic generation was observed and the harmonics show larger variations with the external magnetic field than the fundamental frequency. The super high sensitivity of the harmonics is promising as regards the increase of the sensitivity of magnetoimpedance sensors.

  5. Forearm skin tissue dielectric constant measured at 300 MHz: effect of changes in skin vascular volume and blood flow.

    Science.gov (United States)

    Mayrovitz, Harvey N; Guo, Xiaoran; Salmon, Mark; Uhde, Matt

    2013-01-01

    Skin tissue dielectric constant (TDC) values measured via the open-ended coaxial probe method are useful non-invasive indices of local skin tissue water. However, the effect of skin blood flow (SBF) or skin blood volume (SBV) on TDC values is unknown. To determine the magnitude of such effects, we decreased forearm SBV via vertical arm raising for 5 min (test 1) and increased SBV by bicep cuff compression to 50 mmHg for 5 min (test 2) in 20 healthy supine subjects (10 men). TDC values were measured to a depth of 1·5 mm on anterior forearm, and SBF was measured with laser-Doppler system simultaneously on forearm and finger. Results indicate that decreasing vascular volume (test 1) was associated with a small but statistically significant reduction in TDC (3·0 ± 4·3%, P = 0·003) and increasing vascular volume (test 2) was associated with a slight but statistically significant increase in TDC (3·5 ± 3·0%, PTDC values (3·0-3·5%) over the wide range of induced SBV and SBF changes suggest a minor effect on clinically determined TDC values because of SBV or SBF changes or differences when comparing TDC longitudinally over time or among individuals of different groups in a research setting.

  6. Effects of Analog-to-Digital Converter Nonlinearities on Radar Range-Doppler Maps

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Dubbert, Dale F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Tise, Bertice L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-07-01

    Radar operation, particularly Ground Moving Target Indicator (GMTI) radar modes, are very sensitive to anomalous effects of system nonlinearities. These throw off harmonic spurs that are sometimes detected as false alarms. One significant source of nonlinear behavior is the Analog to Digital Converter (ADC). One measure of its undesired nonlinearity is its Integral Nonlinearity (INL) specification. We examine in this report the relationship of INL to GMTI performance.

  7. Transmission of phototherapy through human skin: dosimetry adjustment for effects of skin color, body composition, wavelength, and light coupling to skin

    Science.gov (United States)

    Nussbaum, Ethne L.; Van Zuylen, Jeff

    2006-02-01

    Purpose: To examine factors that affect penetration of phototherapy. Methods: Age, sex, height, and weight were recorded; skin color, skinfold thickness, and light transmission through a skinfold were measured over biceps and triceps muscles, and at the anterior waistline. Light was generated using two 23-diode LED arrays at 840 nm and 660 nm with surface area of 7 cm2. Photon irradiation was measured using an Optical Power Meter consisting of a 1x1-cm2 light detector placed in the centre of the illuminated 7 cm2 spot. Transmission was measured using three skin-diode coupling conditions. Results: Penetration of LED irradiation increased when diodes were coupled to skin with pressure. Red light attenuated more rapidly than infrared light and the attenuation of red light increased as skin color darkened. Penetration of red and infrared light decreased as the amount of subcutaneous fat increased. There were gender effects on penetration of infrared light at normal and low BMI values. Conclusions: When using divergent light sources for phototherapy, radiant exposure should take into account individual physical characteristics, irradiation wavelength and diode configuration of the laser therapy system.

  8. Skin Effect of Reversely Switched Dynistor in Short Pulse Discharge Application

    Institute of Scientific and Technical Information of China (English)

    Lin Liang; Yue-Hui Yu

    2009-01-01

    The skin effect in the reversely switched dynistor (RSD) devices is investigated in this paper. Based on the plasma bipolar drift model of the RSD, the current density distributions on the chip are simulated with considering the skin effect. The results indicate that the current density on the border can be several hundred to a thousand A/cm2 higher than that in the center of the chip. The skin effect becomes more prominent as the voltage increases and the inductance decreases in the main circuit. The phenomenon that most of a certain group of chips break over on the border has proved the existence of the skin effect.

  9. Development and Validation of a Tokamak Skin Effect Transformer model

    CERN Document Server

    Romero, J A; Coda, S; Felici, F; Garrido, I

    2012-01-01

    A control oriented, lumped parameter model for the tokamak transformer including the slow flux penetration in the plasma (skin effect transformer model) is presented. The model does not require detailed or explicit information about plasma profiles or geometry. Instead, this information is lumped in system variables, parameters and inputs. The model has an exact mathematical structure built from energy and flux conservation theorems, predicting the evolution and non linear interaction of the plasma current and internal inductance as functions of the primary coil currents, plasma resistance, non-inductive current drive and the loop voltage at a specific location inside the plasma (equilibrium loop voltage). Loop voltage profile in the plasma is substituted by a three-point discretization, and ordinary differential equations are used to predict the equilibrium loop voltage as function of the boundary and resistive loop voltages. This provides a model for equilibrium loop voltage evolution, which is reminiscent ...

  10. Vascular effects of leukotriene D4 in human skin

    DEFF Research Database (Denmark)

    Bisgaard, H

    1987-01-01

    the increase in blood flow rate, but did not abolish the response to LTD4. Local nerve block inhibited the axon reflex-mediated flare component of the LTD4-induced blood flow rate, leaving a local red reaction. This local red reaction was not affected by H1 and H2 antagonists. These results indicate histamine...... as a mediator of the axon reflex, and show that LTD4 causes a direct vasodilatory effect that is not mediated via histamine or cyclooxygenase products. The laser-Doppler flowmeter was applied for dynamic studies of the vasopressor response in the skin during a Valsalva maneuver, and the relative changes...... in blood flow were confirmed by control estimates of the blood flow rate by a 133xenon washout method. The pressor response to a Valsalva maneuver was reversed by local nerve block, but not affected by LTD4. Therefore LTD4 did not interfere with the sympathetic activity on the cutaneous vessels...

  11. Nonlinear cosmological consistency relations and effective matter stresses

    Energy Technology Data Exchange (ETDEWEB)

    Ballesteros, Guillermo [Museo Storico della Fisica e Centro Studi e Ricerche ' ' Enrico Fermi' ' , Piazza del Viminale 1, I-00184 Rome (Italy); Hollenstein, Lukas; Jain, Rajeev Kumar; Kunz, Martin, E-mail: guillermo.ballesteros@pd.infn.it, E-mail: lukas.hollenstein@unige.ch, E-mail: rajeev.jain@unige.ch, E-mail: martin.kunz@unige.ch [Département de Physique Théorique and Center for Astroparticle Physics, Université de Genève, Quai E. Ansermet 24, CH-1211 Genève 4 (Switzerland)

    2012-05-01

    We propose a fully nonlinear framework to construct consistency relations for testing generic cosmological scenarios using the evolution of large scale structure. It is based on the covariant approach in combination with a frame that is purely given by the metric, the normal frame. As an example, we apply this framework to the ΛCDM model, by extending the usual first order conditions on the metric potentials to second order, where the two potentials start to differ from each other. We argue that working in the normal frame is not only a practical choice but also helps with the physical interpretation of nonlinear dynamics. In this frame, effective pressures and anisotropic stresses appear at second order in perturbation theory, even for ''pressureless'' dust. We quantify their effect and compare them, for illustration, to the pressure of a generic clustering dark energy fluid and the anisotropic stress in the DGP model. Besides, we also discuss the effect of a mismatch of the potentials on the determination of galaxy bias.

  12. The effect of dietary and/or cosmetic argan oil on postmenopausal skin elasticity.

    Science.gov (United States)

    Boucetta, Kenza Qiraouani; Charrouf, Zoubida; Aguenaou, Hassan; Derouiche, Abdelfattah; Bensouda, Yahya

    2015-01-01

    During menopause, the decrease of estrogenic secretion induces the disruption of skin functioning, thus causing the decline in skin elasticity characteristic of skin aging. The purpose of this study was to evaluate in postmenopausal women the effect of daily consumption and/or application of argan oil on skin elasticity. Sixty postmenopausal women consumed butter during the stabilization period and were randomly divided into two groups for the intervention period: the treatment group of 30 participants received dietary argan oil, the control group of 30 participants received olive oil, and both groups applied cosmetic argan oil in the left volar forearm during a 60-day period. Assessments of skin elasticity parameters, ie, the three R-parameters (R2 or gross-elasticity of the skin, R5 or net elasticity of the skin, and R7 or biological elasticity), and the resonance running time (RRT) at both volar forearms of the two groups were performed during three visits: before starting oils consumption and application, after 30 days of oils consumption and application, and after 60 days of oils consumption and application. The consumption of argan oil led to a significant increase of gross-elasticity of the skin (R2) (Pargan oil led to a significant increase of gross-elasticity of the skin (R2) (Pargan oil have an anti-aging effect on the skin demonstrated by the improvement of skin elasticity, characterized by an increase of R-parameters (R2, R5, and R7) and a decrease of RRT.

  13. Finite temperature Casimir effect in the presence of nonlinear dielectrics

    CERN Document Server

    Kheirandish, Fardin; Soltani, Morteza

    2010-01-01

    Starting from a Lagrangian, electromagnetic field in the presence of a nonlinear dielectric medium is quantized using path-integral techniques and correlation functions of different fields are calculated. The susceptibilities of the nonlinear medium are obtained and their relation to coupling functions are determined. Finally, the Casimir energy and force in the presence of a nonlinear medium at finite temperature is calculated.

  14. Thermopiezoelectric and Nonlinear Electromechanical Effects in Quantum Dots and Nanowires

    Science.gov (United States)

    Patil, Sunil; Bahrami-Samani, M.; Melnik, R. V. N.; Toropova, M.; Zu, Jean

    2010-01-01

    We report thermopiezoelectric (TPE) and nonlinear electromechanical (NEM) effects in quantum dots (QD) and nanowires (NW) analyzed with a model based on coupled thermal, electric and mechanical balance equations. Several representative examples of low dimensional semiconductor structures (LDSNs) are studied. We focus mainly on GaN/AlN QDs and CdTe/ZnTe NWs which we analyze for different geometries. GaN/AlN nano systems are observed to be more sensitive to thermopiezoelectric effects than those of CdTe/ZnTe. Furthermore, noticeable qualitative and quantitative variations in electromechanical fields are observed as a consequence of taking into account NEM effects, in particular in GaN/AlN QDs.

  15. Global non-linear effect of temperature on economic production.

    Science.gov (United States)

    Burke, Marshall; Hsiang, Solomon M; Miguel, Edward

    2015-11-12

    Growing evidence demonstrates that climatic conditions can have a profound impact on the functioning of modern human societies, but effects on economic activity appear inconsistent. Fundamental productive elements of modern economies, such as workers and crops, exhibit highly non-linear responses to local temperature even in wealthy countries. In contrast, aggregate macroeconomic productivity of entire wealthy countries is reported not to respond to temperature, while poor countries respond only linearly. Resolving this conflict between micro and macro observations is critical to understanding the role of wealth in coupled human-natural systems and to anticipating the global impact of climate change. Here we unify these seemingly contradictory results by accounting for non-linearity at the macro scale. We show that overall economic productivity is non-linear in temperature for all countries, with productivity peaking at an annual average temperature of 13 °C and declining strongly at higher temperatures. The relationship is globally generalizable, unchanged since 1960, and apparent for agricultural and non-agricultural activity in both rich and poor countries. These results provide the first evidence that economic activity in all regions is coupled to the global climate and establish a new empirical foundation for modelling economic loss in response to climate change, with important implications. If future adaptation mimics past adaptation, unmitigated warming is expected to reshape the global economy by reducing average global incomes roughly 23% by 2100 and widening global income inequality, relative to scenarios without climate change. In contrast to prior estimates, expected global losses are approximately linear in global mean temperature, with median losses many times larger than leading models indicate.

  16. Global non-linear effect of temperature on economic production

    Science.gov (United States)

    Burke, Marshall; Hsiang, Solomon M.; Miguel, Edward

    2015-11-01

    Growing evidence demonstrates that climatic conditions can have a profound impact on the functioning of modern human societies, but effects on economic activity appear inconsistent. Fundamental productive elements of modern economies, such as workers and crops, exhibit highly non-linear responses to local temperature even in wealthy countries. In contrast, aggregate macroeconomic productivity of entire wealthy countries is reported not to respond to temperature, while poor countries respond only linearly. Resolving this conflict between micro and macro observations is critical to understanding the role of wealth in coupled human-natural systems and to anticipating the global impact of climate change. Here we unify these seemingly contradictory results by accounting for non-linearity at the macro scale. We show that overall economic productivity is non-linear in temperature for all countries, with productivity peaking at an annual average temperature of 13 °C and declining strongly at higher temperatures. The relationship is globally generalizable, unchanged since 1960, and apparent for agricultural and non-agricultural activity in both rich and poor countries. These results provide the first evidence that economic activity in all regions is coupled to the global climate and establish a new empirical foundation for modelling economic loss in response to climate change, with important implications. If future adaptation mimics past adaptation, unmitigated warming is expected to reshape the global economy by reducing average global incomes roughly 23% by 2100 and widening global income inequality, relative to scenarios without climate change. In contrast to prior estimates, expected global losses are approximately linear in global mean temperature, with median losses many times larger than leading models indicate.

  17. Research on testing the nonlinear optical performance of nonlinear optical materials based on the effect of second-harmonic generation.

    Science.gov (United States)

    Li, Bing-Xuan; Wei, Yong; Huang, Cheng-Hui; Zhuang, Feng-Jiang; Zhang, Ge; Guo, Guo-Cong

    2014-01-01

    In the present paper the authors report a research on testing the nonlinear optical performance of optical materials in visible and infrared band. Based on the second order nonlinear optic principle and the photoelectric signal detection technology, the authors have proposed a new testing scheme in which a infrared OPO laser and a method for separating the beams arising from frequency matching and the light produced by other optical effects were used. The OPO laser is adopted as light source to avoid the error of measurement caused by absorption because the double frequency signal of the material is in the transmittance band Our research work includes testing system composition, operational principle and experimental method. The experimental results of KTP, KDP, AGS tested by this method were presented. In the experiment several new infrared non-linear materials were found. This method possesses the merits of good stability and reliability, high sensitivity, simple operation and good reproducibility, which can effectively make qualitative and semi-quantitative test for optical material's nonlinear optical properties from visible to infrared. This work provides an important test -method for the research on second order nonlinear optical materials in visible, infrared and ultraviolet bands.

  18. Effect of seasonal and geographical differences on skin and effect of treatment with an osmoprotectant: Sorbitol.

    Science.gov (United States)

    Muizzuddin, Neelam; Ingrassia, Michael; Marenus, Kenneth D; Maes, Daniel H; Mammone, Thomas

    2013-01-01

    Human skin maintains an optimal permeability barrier function in a terrestrial environment that varies considerably in humidity. Cells cultured under hyperosmotic stress accumulate osmolytes including sorbitol. Epidermal keratinocytes experience similar high osmolality under dry environmental conditions because of increased transepidermal water loss (TEWL) and concomitant drying of the skin. This study was designed to determine if epidermal keratinocytes, in vitro, could be protected from high osmotic stress, with the exogenous addition of sorbitol. In addition, we evaluated the effect of a formulation containing topical sorbitol on skin barrier and moisturization of subjects living in arid and humid regions in summer as well as in winter. Results from in vitro experiments showed that 50 mM sorbitol protected epidermal keratinocytes from osmotic toxicity induced by sodium chloride. Clinical studies indicated that skin chronically exposed to hot, dry environment appeared to exhibit stronger skin barrier and a lower baseline TEWL. In addition, skin barrier was stronger in summer than in winter. Sorbitol exhibited significant improvement in both barrier repair and moisturization, especially in individuals subjected to arid environmental conditions.

  19. Imaging the anisotropic nonlinear Meissner effect in unconventional superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Zhuravel, Alexander P. [B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, Kharkov (Ukraine); Ghamsari, Behnood G.; Kurter, Cihan; Abrahams, John [CNAM, Physics Department, University of Maryland, College Park, MD (United States); Jung, Philipp; Lukashenko, Alexander; Ustinov, Alexey V. [Physikalisches Institut and DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology, Karlsruhe (Germany); Remillard, Stephen [Physics Department, Hope College, Holland, MI (United States); Anlage, Steven M. [CNAM, Physics Department, University of Maryland, College Park, MD (United States); Physikalisches Institut and DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2013-07-01

    We present measurements on the anisotropic nonlinear Meissner effect (aNLME). Using a laser scanning microscope we have directly imaged this effect in a self-resonant spiral patterned from a thin film of the d{sub x{sup 2}-y{sup 2}} superconductor YBa{sub 2}Cu{sub 3}O{sub 7-δ}. The spiral is excited at one of its resonant frequencies while a focused laser spot is scanned across its surface. The local illumination by the laser gives rise to a detectable change in the resonant properties. At low temperatures, the aNLME causes a direction dependent contribution to the critical current density. This makes it possible to image the directions of nodes and anti-nodes of the superconducting order parameter and the contribution of Andreev bound states associated with them. These two contributions to the photoresponse can be distinguished by their temperature dependence, which is consistent with theoretical predictions.

  20. New Relativistic Effects in the Dynamics of Nonlinear Hydrodynamical Waves

    CERN Document Server

    Rezzolla, L

    2002-01-01

    In Newtonian and relativistic hydrodynamics the Riemann problem consists of calculating the evolution of a fluid which is initially characterized by two states having different values of uniform rest-mass density, pressure and velocity. When the fluid is allowed to relax, one of three possible wave-patterns is produced, corresponding to the propagation in opposite directions of two nonlinear hydrodynamical waves. New effects emerge in a special relativistic Riemann problem when velocities tangential to the initial discontinuity surface are present. We show that a smooth transition from one wave-pattern to another can be produced by varying the initial tangential velocities while otherwise maintaining the initial states unmodified. These special relativistic effects are produced by the coupling through the relativistic Lorentz factors and do not have a Newtonian counterpart.

  1. Estimation of Nonlinear Dynamic Panel Data Models with Individual Effects

    Directory of Open Access Journals (Sweden)

    Yi Hu

    2014-01-01

    Full Text Available This paper suggests a generalized method of moments (GMM based estimation for dynamic panel data models with individual specific fixed effects and threshold effects simultaneously. We extend Hansen’s (Hansen, 1999 original setup to models including endogenous regressors, specifically, lagged dependent variables. To address the problem of endogeneity of these nonlinear dynamic panel data models, we prove that the orthogonality conditions proposed by Arellano and Bond (1991 are valid. The threshold and slope parameters are estimated by GMM, and asymptotic distribution of the slope parameters is derived. Finite sample performance of the estimation is investigated through Monte Carlo simulations. It shows that the threshold and slope parameter can be estimated accurately and also the finite sample distribution of slope parameters is well approximated by the asymptotic distribution.

  2. The linear and nonlinear optical effects of white light

    Institute of Scientific and Technical Information of China (English)

    QI XinYuan; LIU SiMin; GUO Ru; LU Yi; GAO YuanMei; LIU ZhaoHong; HUANG ChunFu; ZHANG XiaoHua; ZHU Nan; XU JingJun

    2009-01-01

    An overview of our research group's experimental and theoretical developments is provided on the linear and nonlinear optical effects of white light since 2003. Their work includes the experimental researches on the white light one-dimensional photovoltaic dark spatial solitons and the waveguides and directional couplers induced by them, the circular and elliptic white-light dark spatial solitons and the white-light photorefractive phase masks, two-dimensional white-light photonic lattices and the applications of the white-light dark spatial solitons in the digital image transmission field, the interaction between the two-dimensional white-light dark spatial solitons to enhance or to improve the correlateddegree of the white light through the interaction between the white-light beam and coherent dark spatial solitons, the interaction between the one-or two-dimensional white-light dark spatial solitons and the two-dimensional white-light photonic lattices, respectively. We also numerically simulate the interaction between two or more partially incoherent bright spatial solitons and the white bright spatial soliton pairs in the saturated logarithmic nonlinear medium. We have observed experimentally for the first time,the modulation instability of the coherent light and white light, respectively, in self-defocusing medium and so on.

  3. The linear and nonlinear optical effects of white light

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    An overview of our research group’s experimental and theoretical developments is provided on the linear and nonlinear optical effects of white light since 2003. Their work includes the experimental researches on the white light one-dimensional photovoltaic dark spatial solitons and the waveguides and directional couplers induced by them, the circular and elliptic white-light dark spatial solitons and the white-light photorefractive phase masks, two-dimensional white-light photonic lattices and the applications of the white-light dark spatial solitons in the digital image transmission field, the interaction between the two-dimensional white-light dark spatial solitons to enhance or to improve the correlated degree of the white light through the interaction between the white-light beam and coherent dark spatial solitons, the interaction between the one- or two-dimensional white-light dark spatial solitons and the two-dimensional white-light photonic lattices, respectively. We also numerically simulate the interaction between two or more partially incoherent bright spatial solitons and the white bright spatial soliton pairs in the saturated logarithmic nonlinear medium. We have observed experimentally for the first time, the modulation instability of the coherent light and white light, respectively, in self-defocusing medium and so on.

  4. The effects of surfactants on penetration across the skin*.

    Science.gov (United States)

    Walters, K A; Bialik, W; Brain, K R

    1993-12-01

    Synopsis Many of the properties of surfactants can be related to their ability to concentrate at phase interfaces, leading to a reduction in interracial tension. In biological systems the effects of surfactants are complex, particularly their effect on cell and other membranes, and this can lead to alterations in permeability characteristics. This is of particular relevance when considering the stratum corneum which has long been recognized as the major barrier to skin permeation. The magnitude of skin barrier function alteration is dependent on surfactant structure, both the hydrophobic alkyl chain and the hydropnilic ethylene oxide chain demonstrating some structure-activity behaviour. In many biological systems, including skin, surfactants with a similar hydrophilic group will show maximum membrane activity if they possess a decyl or dodecyl alkyl chain. It is difficult to rationalise this phenomenon, given that such solution properties as partition coefficients and CMCs do not show maxima or minima at these chain lengths. It may be that the physical parameters and molecular dimensions of the decyl/dodecyl chain provide the optimal ability to intercalate with the lipid bilayer structure. There is little doubt that once the surfactant has intercalated with the lipid bilayers in the lamellar liquid crystals of the stratum corneum, fluidity in the hydrophobic regions is increased. Effectively, this leads to a looser, more permeable structure. The significance of data obtained using commercially available surfactants, however, can be questioned on the grounds of purity. The purpose of this review is to describe some of the methods used to evaluate the effects of surfactants on the skin barrier and to discuss recent attempts to predict surfactant action on the skin using various biological and physical techniques. Résumé La plupart des propriétés des surfactants dépend de leur facilitéà se concentrer aux interfaces, menant ainsi à la réduction de la tension

  5. Non-linear mixed-effects pharmacokinetic/pharmacodynamic modelling in NLME using differential equations

    DEFF Research Database (Denmark)

    Tornøe, Christoffer Wenzel; Agersø, Henrik; Madsen, Henrik

    2004-01-01

    The standard software for non-linear mixed-effect analysis of pharmacokinetic/phar-macodynamic (PK/PD) data is NONMEM while the non-linear mixed-effects package NLME is an alternative as tong as the models are fairly simple. We present the nlmeODE package which combines the ordinary differential...... equation (ODE) solver package odesolve and the non-Linear mixed effects package NLME thereby enabling the analysis of complicated systems of ODEs by non-linear mixed-effects modelling. The pharmacokinetics of the anti-asthmatic drug theophylline is used to illustrate the applicability of the nlme...

  6. Ultrasound enhanced skin-lightening effect of vitamin C and niacinamide.

    Science.gov (United States)

    Hakozaki, Tomohiro; Takiwaki, Hirotsugu; Miyamoto, Kukizo; Sato, Yasuhiro; Arase, Seiji

    2006-05-01

    Cutaneous hyperpigmentation occurs in multiple conditions. There is a strong need for the improvement of hyperpigmentation especially among Asian women. However, the effect of existing skin-lightening agents is not sufficient. One reason attributes to the limited capability of active agents to be delivered transepidermally. Ultrasound is one promising approach to enhance transepidermal transport. In this work, we investigate the effect of the use of high-frequency ultrasound together with coupling gel containing skin-lightening agents (ascorbyl glucoside and niacinamide) on facial hyperpigmentation in vivo in Japanese women. The effect of ultrasound on the absorption of skin-lightening agents into the stratum corneum was evaluated in a tape-stripping method on human forearms in vivo. The skin efficacy was assessed in a facial clinical trial involving 60 subjects with hyperpigmentation in a paired design. Subjects were assigned to two groups, each group using two treatments (one on each facial cheek): (1) skin-lightening gel with ultrasound vs. no treatment or (2) skin-lightening gel with ultrasound vs. skin-lightening gel treatment. Changes in facial hyperpigmentation were objectively quantified by computer analysis and visual grading of high-resolution digital images of the face in addition to the subjective assessment via questionnaire. Ultrasound radiation enhanced the absorption of skin-lightening agents in the stratum corneum in a radiation-time-dependent manner. In the facial clinical trial, use of ultrasound radiation together with the skin-lightening gel significantly reduced facial hyperpigmented spots compared with both no treatment and skin-lightening gel alone after 4 weeks. The data suggest that use of high-frequency ultrasound radiation together with skin-lightening gel is effective to reduce hyperpigmentation via enhancing transepidermal transport of skin-lightening agents.

  7. In vitro percutaneous absorption of chromium powder and the effect of skin cleanser.

    Science.gov (United States)

    Larese Filon, Francesca; D'Agostin, Flavia; Crosera, Matteo; Adami, Gianpiero; Bovenzi, Massimo; Maina, Giovanni

    2008-09-01

    The present study tried to investigate, using a synthetic sweat at pH 4.5, whether metallic chromium can pass through the skin (in vitro) and the effect of rapid skin decontamination with a common detergent. A suspension of chromium powder in synthetic sweat at pH 4.5 was prepared and shaken with a stirring plate at room temperature for 30 min. Human skin membranes were set up in Franz-diffusion cells and 1 ml of the freshly made suspension was applied to the outer surface of the skin for 24h. The tests were performed without and with decontamination using the cleanser 30 min after the start of exposure. The appearance of metal ions in the aqueous receptor phase was quantified by Electro Thermal Atomic Absorption Spectroscopy (ETAAS) and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). Speciation analysis and measurements of chromium skin content were also performed. Chromium skin permeation was demonstrated in in vitro experiments using the Franz cell system, giving a permeation flux of 0.84+/-0.25 ng cm(-2)h(-1) and a lag time of 1.1+/-0.7h. The cleaning procedure stop Cr permeation but its concentration into the skin significantly increased (Mann-Whitney U test P<0.03). The results revealed that chromium applied as powder can pass through the skin and that decontamination, done after 30 min of exposure, prevent Cr skin permeation but increase Cr content into the skin.

  8. [In vitro percutaneous absorption of chromium powder and the effect of skin cleanser].

    Science.gov (United States)

    D'Agostin, F; Crosera, M; Adami, G; Malvestio, A; Rosani, R; Bovenzi, M; Maina, G; Filon, F Larese

    2007-01-01

    Occupational chromium dermatitis occurs frequently among cement and metal workers, workers dealing with leather tanning and employees in the ceramic industry. The present study, using an in-vitro system, evaluated percutaneous absorption of chromium powder and the effect of rapid skin decontamination with a common detergent. Experiments were performed using the Franz diffusion cell method with human skin. Physiological solution was used as receiving phase and a suspension of chromium powder in synthetic sweat was used as donor phase. The tests were performed without or with decontamination using the cleanser 30 minutes after the start of exposure. The amount of chromium permeated through the skin was analysed by Inductively Coupled Plasma Atomic Emission Spectroscopy and Electro Thermal Atomic Absorption Spectroscopy. Speciation analysis and measurements of chromium skin content were also performed. We calculated a permeation flux of 0.843 +/- 0.25 ng cm(-2) h(-1) and a lag time of 1.1 +/- 0.7 h. The cleaning procedure significantly increased chromium skin content, whereas skin passage was not increased. These results showed that chromium powder can pass through the skin and that skin decontamination did not decrease skin absorption. Therefore, it is necessary to prevent skin contamination when using toxic agents.

  9. Effectiveness Evaluation of Skin Covers against Intravascular Brachytherapy Sources Using VARSKIN3 Code

    Directory of Open Access Journals (Sweden)

    Baghani HR

    2013-12-01

    Full Text Available Background and Objective: The most common intravascular brachytherapy sources include 32P, 188Re, 106Rh and 90Sr/90Y. In this research, skin absorbed dose for different covering materials in dealing with these sources were evaluated and the best covering material for skin protection and reduction of absorbed dose by radiation staff was recognized and recommended. Method: Four materials including polyethylene, cotton and two different kinds of plastic were proposed as skin covers and skin absorbed dose at different depths for each kind of the materials was calculated separately using the VARSKIN3 code. Results: The results suggested that for all sources, skin absorbed dose was minimized when using polyethylene. Considering this material as skin cover, maximum and minimum doses at skin surface were related to 90Sr/90Y and 106Rh, respectively. Conclusion: polyethylene was found the most effective cover in reducing skin dose and protecting the skin. Furthermore, proper agreement between the results of VARSKIN3 and other experimental measurements indicated that VRASKIN3 is a powerful tool for skin dose calculations when working with beta emitter sources. Therefore, it can be utilized in dealing with the issue of radiation protection.

  10. EASApprox® skin-stretching system: A secure and effective method to achieve wound closure

    Science.gov (United States)

    Song, Mingzhi; Zhang, Zhen; Liu, Tao; Liu, Song; Li, Gang; Liu, Zhaochang; Huang, Jingyang; Chen, Song; Li, Linan; Guo, Li; Qiu, Yang; Wan, Jiajia; Liu, Yuejian; Wu, Tao; Wang, Xiaoyong; Lu, Ming; Wang, Shouyu

    2017-01-01

    Large skin defects are commonly observed in the clinic and have attracted much attention recently. Therefore, finding an effective solution for large skin defects is a global problem. The objective of the present study was to assess the effectiveness of the EASApprox® skin-stretching system for closing large skin defects. Skin defects (5×5 cm) were created on the forearms of 9 Bama miniature pigs, which were randomly divided into the following three groups: Direct suture, the new EASApprox® skin-stretching device and Kirschner wires. Microcirculation was assessed before surgery and after wound closure. Following the different treatments, the defects were sutured, and wound healing was assessed based on a clinical score. Furthermore, microscopic and ultramicroscopic structures were evaluated, including collagen, elastic fibers and the microvessel density. Significant differences in the clinical score and microvessel density were observed among the groups. Additionally, the mean length obtained for elastic fibers was larger than that obtained for the other two groups. Finally, the new EASApprox® skin-stretching device resulted in successful wound management and with only minor side effects on skin histology and microcirculation. Therefore, this method has the potential to be used for healing large skin defects. PMID:28672963

  11. Impact of nonlinear effective interactions on GFT quantum gravity condensates

    CERN Document Server

    Pithis, Andreas G A; Tomov, Petar

    2016-01-01

    We present the numerical analysis of effectively interacting Group Field Theory (GFT) models in the context of the GFT quantum gravity condensate analogue of the Gross-Pitaevskii equation for real Bose-Einstein condensates including combinatorially local interaction terms. Thus we go beyond the usually considered construction for free models. More precisely, considering such interactions in a weak regime, we find solutions for which the expectation value of the number operator N is finite, as in the free case. When tuning the interaction to the strongly nonlinear regime, however, we obtain solutions for which N grows and eventually blows up, which is reminiscent of what one observes for real Bose-Einstein condensates, where a strong interaction regime can only be realized at high density. This behaviour suggests the breakdown of the Bogoliubov ansatz for quantum gravity condensates and the need for non-Fock representations to describe the system when the condensate constituents are strongly correlated. Furthe...

  12. The chaotic effects in a nonlinear QCD evolution equation

    Science.gov (United States)

    Zhu, Wei; Shen, Zhenqi; Ruan, Jianhong

    2016-10-01

    The corrections of gluon fusion to the DGLAP and BFKL equations are discussed in a united partonic framework. The resulting nonlinear evolution equations are the well-known GLR-MQ-ZRS equation and a new evolution equation. Using the available saturation models as input, we find that the new evolution equation has the chaos solution with positive Lyapunov exponents in the perturbative range. We predict a new kind of shadowing caused by chaos, which blocks the QCD evolution in a critical small x range. The blocking effect in the evolution equation may explain the Abelian gluon assumption and even influence our expectations to the projected Large Hadron Electron Collider (LHeC), Very Large Hadron Collider (VLHC) and the upgrade (CppC) in a circular e+e- collider (SppC).

  13. Effective action and vacuum expectations in nonlinear $\\sigma$ model

    CERN Document Server

    Fayzullaev, B A

    2015-01-01

    The equations for effective action for nonlinear $\\sigma$ model are derived using DeWitt method in two forms - for generator of vertex parts $\\Gamma$ and for generator of weakly connected parts $W$. Loop-expansion solutions to these equations are found. It is shown that vacuum expectation values for various quantities including divergence of a N\\"{o}ther current, trace of the energy-momentum tensor and so on, can be calculated by this method. Also it is shown that vacuum expectation to the sigma-field is determined by an explicit combination of tree Green function and classical solution. It is shown that the limit when coupling constant tends to zero is singular one.

  14. Crystal growth in fluid flow: Nonlinear response effects

    Science.gov (United States)

    Peng, H. L.; Herlach, D. M.; Voigtmann, Th.

    2017-08-01

    We investigate crystal-growth kinetics in the presence of strong shear flow in the liquid, using molecular-dynamics simulations of a binary-alloy model. Close to the equilibrium melting point, shear flow always suppresses the growth of the crystal-liquid interface. For lower temperatures, we find that the growth velocity of the crystal depends nonmonotonically on the shear rate. Slow enough flow enhances the crystal growth, due to an increased particle mobility in the liquid. Stronger flow causes a growth regime that is nearly temperature-independent, in striking contrast to what one expects from the thermodynamic and equilibrium kinetic properties of the system, which both depend strongly on temperature. We rationalize these effects of flow on crystal growth as resulting from the nonlinear response of the fluid to strong shearing forces.

  15. Allergic Responses Induced by the Immunomodulatory Effects of Nanomaterials upon Skin Exposure

    Science.gov (United States)

    Yoshioka, Yasuo; Kuroda, Etsushi; Hirai, Toshiro; Tsutsumi, Yasuo; Ishii, Ken J.

    2017-01-01

    Over the past decade, a vast array of nanomaterials has been created through the development of nanotechnology. With the increasing application of these nanomaterials in various fields, such as foods, cosmetics, and medicines, there has been concern about their safety, that is, nanotoxicity. Therefore, there is an urgent need to collect information about the biological effects of nanomaterials so that we can exploit their potential benefits and design safer nanomaterials, while avoiding nanotoxicity as a result of inhalation or skin exposure. In particular, the immunomodulating effect of nanomaterials is one of most interesting aspects of nanotoxicity. However, the immunomodulating effects of nanomaterials through skin exposure have not been adequately discussed compared with the effects of inhalation exposure, because skin penetration by nanomaterials is thought to be extremely low under normal conditions. On the other hand, the immunomodulatory effects of nanomaterials via skin may cause severe problems for people with impaired skin barrier function, because some nanomaterials could penetrate the deep layers of their allergic or damaged skin. In addition, some studies, including ours, have shown that nanomaterials could exhibit significant immunomodulating effects even if they do not penetrate the skin. In this review, we summarize our current knowledge of the allergic responses induced by nanomaterials upon skin exposure. First, we discuss nanomaterial penetration of the intact or impaired skin barrier. Next, we describe the immunomodulating effects of nanomaterials, focusing on the sensitization potential of nanomaterials and the effects of co-exposure of nanomaterials with substances such as chemical sensitizers or allergens, on the onset of allergy, following skin exposure. Finally, we discuss the potential mechanisms underlying the immunomodulating effects of nanomaterials by describing the involvement of the protein corona in the interaction of

  16. Dispersion and nonlinear effects in OFDM-RoF system

    Science.gov (United States)

    Alhasson, Bader H.; Bloul, Albe M.; Matin, M.

    2010-08-01

    The radio-over-fiber (RoF) network has been a proven technology to be the best candidate for the wireless-access technology, and the orthogonal frequency division multiplexing (OFDM) technique has been established as the core technology in the physical layer of next generation wireless communication system, as a result OFDM-RoF has drawn attentions worldwide and raised many new research topics recently. At the present time, the trend of information industry is towards mobile, wireless, digital and broadband. The next generation network (NGN) has motivated researchers to study higher-speed wider-band multimedia communication to transmit (voice, data, and all sorts of media such as video) at a higher speed. The NGN would offer services that would necessitate broadband networks with bandwidth higher than 2Mbit/s per radio channel. Many new services emerged, such as Internet Protocol TV (IPTV), High Definition TV (HDTV), mobile multimedia and video stream media. Both speed and capacity have been the key objectives in transmission. In the meantime, the demand for transmission bandwidth increased at a very quick pace. The coming of 4G and 5G era will provide faster data transmission and higher bit rate and bandwidth. Taking advantages of both optical communication and wireless communication, OFDM Radio over Fiber (OFDM-RoF) system is characterized by its high speed, large capacity and high spectral efficiency. However, up to the present there are some problems to be solved, such as dispersion and nonlinearity effects. In this paper we will study the dispersion and nonlinearity effects and their elimination in OFDM-radio-over-fiber system.

  17. Clinical effects of an oral supplement rich in antioxidants on skin radiance in women

    Science.gov (United States)

    Dumoulin, Marion; Gaudout, David; Lemaire, Benoit

    2016-01-01

    Background Environmental factors impact the skin aging resulting in decrease of skin radiance. Nutrition and particularly antioxidants could help to fight against skin degradation. Objective The aim of this study was to evaluate the effects of an oral supplement rich in specific antioxidants, SkinAx2TM, on the improvement of the skin radiance in women. Methods The open-label clinical study enrolled 35 women, aged 40–70, with facial dull complexion. Subjects were supplemented orally with a daily dosage of 150 mg of an antioxidant-rich formulation containing superoxide dismutase-rich melon concentrate, grape seed extract rich in monomers of flavanols, vitamin C, and zinc for 8 weeks. Each subject served as her own control. The C.L.B.T.™ test has been used to evaluate facial skin coloring (C), luminosity (L), brightness (B), and transparency (T) involved in skin radiance. Facial skin imperfections have been assessed by clinical assessment. Firmness has been evaluated by clinical assessment and cutometer measurement. Finally, an auto-questionnaire has been carried out in order to evaluate the satisfaction of the subjects concerning different parameters involved in skin radiance and the global efficacy of the supplement. Results Skin “red pink” and “olive” colors were significantly improved after supplementation (Pskin imperfections were significantly reduced after the antioxidant-rich formulation intake (global reduction: −18.0%; Pskin. Furthermore, 64.7% reported to look better at the end of the supplementation. Conclusion The oral supplement containing the antioxidant-rich formulation was found to improve skin radiance by reducing skin coloring, increasing face luminosity, reducing imperfections, and improving skin firmness in women with dull complexion. PMID:27799805

  18. The Effect of an Emollient Containing Urea, Ceramide NP, and Lactate on Skin Barrier Structure and Function in Older People with Dry Skin.

    Science.gov (United States)

    Danby, Simon G; Brown, Kirsty; Higgs-Bayliss, Tim; Chittock, John; Albenali, Lujain; Cork, Michael J

    2016-01-01

    Xerosis affects up to 75% of older people and develops as a result of a skin barrier defect. Emollients are widely used to treat xerosis; however, there is limited understanding of the differences between them and their effects on the skin barrier in older people. This study aimed to compare the effect of a commercially available emollient containing 5% urea, ceramide NP and lactate (test emollient) to an alternative emollient without these additives (control emollient) on the properties of the skin barrier in older people. Two cohorts of 21 volunteers aged >60 years with dry skin were recruited. The first applied the test emollient to one forearm and no treatment to the other for 28 days. The second compared the test emollient to the control emollient observing the same parameters. Effects on the skin barrier were determined by measuring skin barrier function, hydration, skin surface pH and by analysing Fourier transform infrared spectra before and after treatment. A third cohort of 6 young adults was recruited to investigate the effect of a single treatment with the test emollient on the molecular structure of the skin barrier at greater depths by employing the tape-stripping technique. The test emollient hydrated the skin to a significantly greater extent and for a longer period of time compared to the control emollient, an effect associated with a significant elevation of carboxylate groups (a marker of natural moisturizing factor content) within the stratum corneum. Furthermore, the test emollient imparted additional benefits to the structure and function of the skin barrier not exhibited by the control emollient. In conclusion, the test emollient addressed the pathological features of xerotic aged skin, supporting its use as first-line therapy for xerotic skin conditions in this population. © 2016 The Author(s) Published by S. Karger AG, Basel.

  19. Proinflammatory Effects of Diesel Exhaust Nanoparticles on Scleroderma Skin Cells

    Directory of Open Access Journals (Sweden)

    A. Mastrofrancesco

    2014-01-01

    Full Text Available Autoimmune diseases are complex disorders of unknown etiology thought to result from interactions between genetic and environmental factors. We aimed to verify whether environmental pollution from diesel engine exhaust nanoparticulate (DEP of actually operating vehicles could play a role in the development of a rare immune-mediated disease, systemic sclerosis (SSc, in which the pathogenetic role of environment has been highlighted. The effects of carbon-based nanoparticulate collected at the exhaust of newer (Euro 5 and older (Euro 4 diesel engines on SSc skin keratinocytes and fibroblasts were evaluated in vitro by assessing the mRNA expression of inflammatory cytokines (IL-1α, IL-6, IL-8, and TNF-α and fibroblast chemical mediators (metalloproteases 2, 3, 7, 9, and 12; collagen types I and III; VEGF. DEP was shown to stimulate cytokine gene expression at a higher extent in SSc keratinocytes versus normal cells. Moreover, the mRNA gene expression of all MMPs, collagen types, and VEGF genes was significantly higher in untreated SSc fibroblasts versus controls. Euro 5 particle exposure increased the mRNA expression of MMP-2, -7, and -9 in SSc fibroblasts in a dose dependent manner and only at the highest concentration in normal cells. We suggest that environmental DEP could trigger the development of SSc acting on genetically hyperreactive cell systems.

  20. The Effects of Dietary Macronutrient Balance on Skin Structure in Aging Male and Female Mice

    Science.gov (United States)

    McMahon, Aisling C.; Ruohonen, Kari; Raubenheimer, David; Ballard, J. William O.; Le Couteur, David G.; Nicholls, Caroline; Li, Zhe; Maitz, Peter K. M.; Wang, Yiwei; Simpson, Stephen J.

    2016-01-01

    Nutrition influences skin structure; however, a systematic investigation into how energy and macronutrients (protein, carbohydrate and fat) affects the skin has yet to be conducted. We evaluated the associations between macronutrients, energy intake and skin structure in mice fed 25 experimental diets and a control diet for 15 months using the Geometric Framework, a novel method of nutritional analysis. Skin structure was associated with the ratio of dietary macronutrients eaten, not energy intake, and the nature of the effect differed between the sexes. In males, skin structure was primarily associated with protein intake, whereas in females carbohydrate intake was the primary correlate. In both sexes, the dermis and subcutaneous fat thicknesses were inversely proportional. Subcutaneous fat thickness varied positively with fat intake, due to enlarged adipocytes rather than increased adipocyte number. We therefore demonstrated clear interactions between skin structure and macronutrient intakes, with the associations being sex-specific and dependent on dietary macronutrient balance. PMID:27832138

  1. Effect of chicken skin on the quality characteristics of semi-dried restructured jerky.

    Science.gov (United States)

    Choi, Yun-Sang; Han, Doo-Jeong; Choi, Ji-Hun; Hwang, Ko-Eun; Song, Dong-Heon; Kim, Hyun-Wook; Kim, Young-Boong; Kim, Cheon-Jei

    2016-05-01

    The objective of this study was to evaluate the effect of skin on the textural properties of semi-dried jerky produced with different acid treatments. Jerky was prepared with no skin (control) or with 1, 3, or 5% chicken skin. After hand mixing (for 3 min) and tumbling (for 30 min) to distribute the curing ingredients, the cured meats were dried for 180 min at 55°C, for 180 min at 65°C, and finally for 60 min at 75°C. The presence of skin was shown to result in a higher fat content, TBA value, and metmyoglobin due to the high fat content of the skin. In contrast, acid treatment decreased the TBA value and metmyoglobin in jerky relative to samples that were not subjected to acid treatment. The presence of skin also improved the moisture contents, processing yields, and mechanical tenderness.

  2. Characterization of nonlinear ultrasonic effects using the dynamic wavelet fingerprint technique

    Science.gov (United States)

    Lv, Hongtao; Jiao, Jingpin; Meng, Xiangji; He, Cunfu; Wu, Bin

    2017-02-01

    An improved dynamic wavelet fingerprint (DWFP) technique was developed to characterize nonlinear ultrasonic effects. The white area in the fingerprint was used as the nonlinear feature to quantify the degree of damage. The performance of different wavelet functions, the effect of scale factor and white subslice ratio on the nonlinear feature extraction were investigated, and the optimal wavelet function, scale factor and white subslice ratio for maximum damage sensitivity were determined. The proposed DWFP method was applied to the analysis of experimental signals obtained from nonlinear ultrasonic harmonic and wave-mixing experiments. It was demonstrated that the proposed DWFP method can be used to effectively extract nonlinear features from the experimental signals. Moreover, the proposed nonlinear fingerprint coefficient was sensitive to micro cracks and correlated well with the degree of damage.

  3. The role of the skin barrier in modulating the effects of common skin microbial species on the inflammation, differentiation and proliferation status of epidermal keratinocytes

    OpenAIRE

    Duckney, Patrick; Wong, Heng Kuan; Serrano, José; Yaradou, Diaraf; Oddos, Thierry; Georgios N. Stamatas

    2013-01-01

    Background Skin resident microbial species are often thought of either as pathogenic or commensal. However, little is known about the role of the skin barrier in modulating their potential for causing disease. To investigate this question we measured the effects of three microbial species commonly found on the skin (Staphylococcus epidermidis, Staphylococcus aureus, and Propionibacterium acnes) on a reconstructed human epidermal model by either applying the bacteria on the model surface (inta...

  4. Axial Compression Properties Nonlinear Analysis on Square Double Skin Steel Stub Short Columns Filled with Recycled Concrete

    Directory of Open Access Journals (Sweden)

    Song Bing

    2016-01-01

    Full Text Available Taking the mixing amount of diatomite calcined and vitrified micro bubbles(VMB as the main changing parameters, experiment studies the properties of the vitrified micro bubbles recycled concrete blocks; then this paper adopts the finite element software ANSYS to analyze the square double skin steel stub short columns filled with recycled concrete under axial compression. According to the vertical stress distribution, strain and bearing capacity of the steel tube and core concrete, we make a contrastive axial compression properties analysis on the different hollow ratio χ(0,0.35and the VMB content(0%,100%,130% of square double skin steel stub short columns filled with recycled concrete. The result shows that: Compressive strength of VMB recycled concrete increases with the increase of diatomite calcined content, when mixing amount of diatomite calcined is 3%,the compressive strength of 130% VMB content test specimen can reach 32.45 MPa;Because of the inner circular steel tube is setted which strengthening component buckling capacity and improving the ductility of the component, stress distribution of hollow components is more balance than solid components, and their axial displacements decrease by 5.6% compared with the solid components when they reach ultimate bearing capacity; When the hollow ratio is same, ultimate bearing capacity of 130% VMB content test specimen compared with the content is 0% only reduces by about 3.5%; When the VMB content is same, ultimate bearing capacity of hollow components compared with solid components increases by about 2.5%, which reducing weight as well as improving the anti-seismic performance.

  5. Temperature effects in a nonlinear model of monolayer Scheibe aggregates

    DEFF Research Database (Denmark)

    Bang, Ole; Christiansen, Peter Leth; If, F.

    1994-01-01

    A nonlinear dynamical model of molecular monolayers arranged in Scheibe aggregates is derived from a proper Hamiltonian. Thermal fluctuations of the phonons are included. The resulting equation for the excitons is the two dimensional nonlinear Schrodinger equation with noise. Two limits...

  6. The effect of skin temperature on performance during a 7.5-km cycling time trial

    NARCIS (Netherlands)

    Levels, K.; Koning, J.J. de; Foster, C.; Daanen, H.A.M.

    2012-01-01

    Aerobic exercise performance is seriously compromised in the heat. Possibly, a high skin temperature causes a rating of perceived exertion (RPE)-mediated decrease in exercise intensity. The purpose of this study was to determine the effect of skin temperature on power output during a 7.5-km cycling

  7. Using a Cell Phone to Investigate the Skin Depth Effect in Salt Water

    Science.gov (United States)

    Rayner, John

    2017-01-01

    This paper describes an experimental investigation of the skin depth effect for electromagnetic waves in salt water using a cell phone that is immersed to a critical depth where it no longer responds when called. We show that this critical depth is directly proportional to the theoretical skin depth for a range of salt concentrations.

  8. Using a Cell Phone to Investigate the Skin Depth Effect in Salt Water

    Science.gov (United States)

    Rayner, John

    2017-02-01

    This paper describes an experimental investigation of the skin depth effect for electromagnetic waves in salt water using a cell phone that is immersed to a critical depth where it no longer responds when called. We show that this critical depth is directly proportional to the theoretical skin depth for a range of salt concentrations.

  9. Effect of age on leather and skin traits of slaughter ostriches

    African Journals Online (AJOL)

    Schalk Cloete

    Little is known about the factors affecting leather and skin traits in ostriches. The effect of age on ... of the skin. It was contended that this measure was adopted to control an ..... Ph.D. dissertation, University of New England, Armidale, Australia.

  10. The hygienic effectiveness of 2 different skin cleansing procedures.

    Science.gov (United States)

    Rönner, Anna-Clara; Berland, Carolyn R; Runeman, Bo; Kaijser, Bertil

    2010-01-01

    This study was designed to assess the ability of 2 skin cleaning procedures to remove transient microbial flora from the skin. The study is a direct comparison of 2 washing procedures: soap and water washing versus cleansing with a no-rinse cleanser. The trial was performed at the research facilities of the Department of Clinical Bacteriology at the University of Göteborg. Forty-five healthy adult volunteers were recruited to participate in the study. A solution of test bacteria, either Escherichia coli or Staphylococcus aureus, was applied to both forearms of the test subject. After a 15-minute incubation period, one arm was cleaned using soap and water and the other arm was cleaned with no-rinse cleanser. Both the arms were dried with a disposable cloth. The amount of residual bacteria on the skin was assessed using contact agar plates. Both methods of cleaning resulted in 4-to 5-fold log reductions in bacterial count. The number of residual bacteria after both procedures ranged from 1 to 4 colony-forming units/cm after washing. The amount of residual bacteria was comparable for both washing procedures. Both washing procedures resulted in a low level of residual bacteria on the skin. No-rinse cleansers can be safely used as an alternative to soap and water washing of fragile skin.

  11. dermaOXY skin assay: effect and evidence

    DEFF Research Database (Denmark)

    Menov, Lasse; Klösgen-Buchkremer, Beate Maria

    2015-01-01

    This text is a videnkupon report supported by the Danish Innovation Fonds and conducted by L.M. and B.K. for dermaOXY (by MedicTinedic ApS, Varde, Denmark). It involves two dermaOXY products: dermaOXY HYALURON SERUM and dermaOXY SYN SERUM. These are applied to the facial skin in combination...... with a 90 percent pure oxygen gas stream. Occasionally, the treatment is supported by low-level light exposure, prepared by mechanical microporation of skin or both. The dermaOXY skin improvement approach is used in treatments by clinics spread across 23 countries [1]. This text also includes an assessment...... of the instrument set DermaLab®Combo, which is used for the physical characterization of skin status after treatment. The report consists of four main parts, dedicated to 1. the properties of human skin 2. the anti-aging methods applied by the dermaOXY treatment 3. the analytical methods applied by derma...

  12. Assessing the impacts of lifetime sun exposure on skin damage and skin aging using a non-invasive method.

    Science.gov (United States)

    Kimlin, Michael G; Guo, Yuming

    2012-05-15

    Ultraviolet radiation exposure during an individuals' lifetime is a known risk factor for the development of skin cancer. However, less evidence is available on assessing the relationship between lifetime sun exposure and skin damage and skin aging. This study aims to assess the relationship between lifetime sun exposure and skin damage and skin aging using a non-invasive measure of exposure. We recruited 180 participants (73 males, 107 females) aged 18-83 years. Digital imaging of skin hyperpigmentation (skin damage) and skin wrinkling (skin aging) on the facial region was measured. Lifetime sun exposure (presented as hours) was calculated from the participants' age multiplied by the estimated annual time outdoors for each year of life. We analyzed the effects of lifetime sun exposure on skin damage and skin aging. We adjust for the influence of age, sex, occupation, history of skin cancer, eye color, hair color, and skin color. There were non-linear relationships between lifetime sun exposure and skin damage and skin aging. Younger participant's skin is much more sensitive to sun exposure than those who were over 50 years of age. As such, there were negative interactions between lifetime sun exposure and age. Age had linear effects on skin damage and skin aging. The data presented showed that self reported lifetime sun exposure was positively associated with skin damage and skin aging, in particular, the younger people. Future health promotion for sun exposure needs to pay attention to this group for skin cancer prevention messaging. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Nonlinear vibration and stability of rotating, pretwisted, preconed blades including Coriolis effects

    Science.gov (United States)

    Subrahmanyam, K. B.; Kaza, K. R. V.; Brown, G. V.; Lawrence, C.

    1987-01-01

    The coupled bending-bending-torsional equations of dynamic motion of rotating, linearly pretwisted blades are derived including large precone, second degree geometric nonlinearities and Coriolis effects. The equations are solved by the Galerkin method and a linear perturbation technique. Accuracy of the present method is verified by conparisons of predicted frequencies and steady state deflections with those from MSC/NASTRAN and from experiments. Parametric results are generated to establish where inclusion of only the second degree geometric nonlinearities is adequate. The nonlinear terms causing torsional divergence in thin blades are identified. The effects of Coriolis terms and several other structurally nonlinear terms are studied, and their relative importance is examined.

  14. Nonlinear bending-torsional vibration and stability of rotating, pretwisted, preconed blades including Coriolis effects

    Science.gov (United States)

    Subrahmanyam, K. B.; Kaza, K. R. V.; Brown, G. V.; Lawrence, C.

    1986-01-01

    The coupled bending-bending-torsional equations of dynamic motion of rotating, linearly pretwisted blades are derived including large precone, second degree geometric nonlinearities and Coriolis effects. The equations are solved by the Galerkin method and a linear perturbation technique. Accuracy of the present method is verified by comparisons of predicted frequencies and steady state deflections with those from MSC/NASTRAN and from experiments. Parametric results are generated to establish where inclusion of only the second degree geometric nonlinearities is adequate. The nonlinear terms causing torsional divergence in thin blades are identified. The effects of Coriolis terms and several other structurally nonlinear terms are studied, and their relative importance is examined.

  15. Effectiveness of hand washing on the removal of iron oxide nanoparticles from human skin ex vivo.

    Science.gov (United States)

    Lewinski, Nastassja A; Berthet, Aurélie; Maurizi, Lionel; Eisenbeis, Antoine; Hopf, Nancy B

    2017-08-01

    In this study, the effectiveness of washing with soap and water in removing nanoparticles from exposed skin was investigated. Dry, nanoscale hematite (α-Fe2O3) or maghemite (γ-Fe2O3) powder, with primary particle diameters between 20-30 nm, were applied to two samples each of fresh and frozen ex vivo human skin in two independent experiments. The permeation of nanoparticles through skin, and the removal of nanoparticles after washing with soap and water were investigated. Bare iron oxide nanoparticles remained primarily on the surface of the skin, without penetrating beyond the stratum corneum. Skin exposed to iron oxide nanoparticles for 1 and 20 hr resulted in removal of 85% and 90%, respectively, of the original dose after washing. In the event of dermal exposure to chemicals, removal is essential to avoid potential local irritation or permeation across skin. Although manufactured at an industrial scale and used extensively in laboratory experiments, limited data are available on the removal of engineered nanoparticles after skin contact. Our finding raises questions about the potential consequences of nanoparticles remaining on the skin and whether alternative washing methods should be proposed. Further studies on skin decontamination beyond use of soap and water are needed to improve the understanding of the potential health consequences of dermal exposure to nanoparticles.

  16. Theoretical Investigation on Skin Effect Factor of Conductor in Power Cables

    Science.gov (United States)

    Suzuki, Hiroshi; Kanaoka, Mamoru

    This paper describes a newly-derived theoretical equation on the skin effect factor of power cables, and its application to large-size OF and XLPE cables with segmental conductors, including insulated wires. The skin effect factors calculated with the new equation were fit very well to measurements in wide range conductor sizes. In the new equation, the important factor which characterizes the skin effect of segmental conductors is the `equivalent conductivity ratio' ν defined by the ratio of longitudinal conductivity in axial direction of conductor to conductivity of conductor wires. Since the obtained ratio ν in XLPE cable was three times greater than that in OF cable, the larger longitudinal eddy current passing from a wire to another increased the eddy current loss in conductor, which increased the conductor loss of XLPE cable. The new equation enables us to investigate quantitatively the dominant loss component affecting the skin effect factor. Then, the skin effect factors and coefficients for OF and XLPE cables were investigated with the new equation. It was revealed that the best number of separation, in which the skin effect became minimum, existed in OF and XLPE cables with segmental conductors. In addition, it was confirmed that the skin effect coefficients ks1 calculated with the new equation were consistent well with those used in JCS.

  17. Reduction of nonlinear patterning effects in SOA-based All-optical Switches using Optical filtering

    DEFF Research Database (Denmark)

    Nielsen, Mads Lønstrup; Mørk, Jesper; Skaguchi, J.

    2005-01-01

    We explain theoretically, and demonstrate and quantify experimentally, how appropriate filtering can reduce the dominant nonlinear patterning effect, which limits the performance of differential-mode SOA-based switches.......We explain theoretically, and demonstrate and quantify experimentally, how appropriate filtering can reduce the dominant nonlinear patterning effect, which limits the performance of differential-mode SOA-based switches....

  18. Explanation of the inverse Doppler effect observed in nonlinear transmission lines.

    Science.gov (United States)

    Kozyrev, Alexander B; van der Weide, Daniel W

    2005-05-27

    The theory of the inverse Doppler effect recently observed in magnetic nonlinear transmission lines is developed. We explain the crucial role of the backward spatial harmonic in the occurrence of an inverse Doppler effect and draw analogies of the magnetic nonlinear transmission line to the backward wave oscillator.

  19. Localized Effects in the Nonlinear Behavior of Sandwich Panels with a Transversely Flexible Core

    DEFF Research Database (Denmark)

    Frostig, Y.; Thomsen, Ole Thybo

    2005-01-01

    nonlinear analysis approach incorporates the effects of the vertical flexibility of the core, and it is based on the approach of the High-order Sandwich Panel Theory (HSAPT). The results demonstrate that the effects of localized loads, when taken into the geometrically nonlinear domain, change the response...

  20. Novel Inhibitory Effect of N-(2-Hydroxycyclohexylvaliolamine on Melanin Production in a Human Skin Model

    Directory of Open Access Journals (Sweden)

    Bum-Ho Bin

    2014-07-01

    Full Text Available Hyper-pigmentation causes skin darkness and medical disorders, such as post-inflammatory melanoderma and melasma. Therefore, the development of anti-melanogenic agents is important for treating these conditions and for cosmetic production. In our previous paper, we demonstrated that the anti-diabetic drug voglibose, a valiolamine derivative, is a potent anti-melanogenic agent. In addition, we proposed an alternative screening strategy to identify valiolamine derivatives with high skin permeability that act as anti-melanogenic agents when applied topically. In this study, we synthesized several valiolamine derivatives with enhanced lipophilicity and examined their inhibitory effects in a human skin model. N-(2-hydroxycyclohexylvaliolamine (HV possesses a stronger inhibitory effect on melanin production than voglibose in a human skin model, suggesting that HV is a more potent anti-melanogenic agent for the skin.

  1. Effects of glycerol on human skin damaged by acute sodium lauryl sulphate treatment.

    Science.gov (United States)

    Atrux-Tallau, Nicolas; Romagny, Céline; Padois, Karine; Denis, Alain; Haftek, Marek; Falson, Françoise; Pirot, Fabrice; Maibach, Howard I

    2010-08-01

    Glycerol, widely used as humectant, is known to protect against irritants and to accelerate recovery of irritated skin. However, most studies were done with topical formulations (i.e. emulsions) containing glycerol in relatively high amounts, preventing drawing conclusions from direct effects. In this study, acute chemical irritations were performed on the forearm with application of a 10% sodium lauryl sulphate (SLS) aqueous solution under occlusion for 3 h. Then, glycerol aqueous solutions from 1 to 10% were applied under occlusion for 3 h. After elimination of moist excess consecutive to occlusive condition, in ambient air for 15 and 30 min, skin barrier function was investigated by dual measurement of skin hydration and transepidermal water loss (TEWL). Treatments with SLS solution under occlusion significantly increased TEWL and decreased skin hydration as assessed by capacitance measurements. The SLS irritant property was raised by the occlusion and the water barrier function as well as water content appeared impaired. Recovery with glycerol at low doses was remarkable through a mechanism that implies its hygroscopic properties and which is saturable. This precocious effect acts through skin rehydration by enhancing water-holding capacity of stratum corneum that would facilitate the late physiological repair of impaired skin barrier. Thus, glycerol appears to substitute for natural moisturizing factors that have been washed out by the detergent action of SLS, enhancing skin hydration but without restoring skin barrier function as depicted by TEWL values that remained high. Thus, irritant contact dermatitis treated with glycerol application compensate for skin dehydration, favouring physiological process to restore water barrier function of the impaired skin. Empirical use of glycerol added topical formulations onto detergent altered skin was substantiated in the present physicochemical approach.

  2. Clinical effects of an oral supplement rich in antioxidants on skin radiance in women

    Directory of Open Access Journals (Sweden)

    Dumoulin M

    2016-10-01

    Full Text Available Marion Dumoulin, David Gaudout, Benoit Lemaire Activ’Inside, Libourne, France Background: Environmental factors impact the skin aging resulting in decrease of skin radiance. Nutrition and particularly antioxidants could help to fight against skin degradation.Objective: The aim of this study was to evaluate the effects of an oral supplement rich in specific antioxidants, SkinAx2TM, on the improvement of the skin radiance in women.Methods: The open-label clinical study enrolled 35 women, aged 40–70, with facial dull complexion. Subjects were supplemented orally with a daily dosage of 150 mg of an antioxidant-rich formulation containing superoxide dismutase-rich melon concentrate, grape seed extract rich in monomers of flavanols, vitamin C, and zinc for 8 weeks. Each subject served as her own control. The C.L.B.T.™ test has been used to evaluate facial skin coloring (C, luminosity (L, brightness (B, and transparency (T involved in skin radiance. Facial skin imperfections have been assessed by clinical assessment. Firmness has been evaluated by clinical assessment and cutometer measurement. Finally, an auto-questionnaire has been carried out in order to evaluate the satisfaction of the subjects concerning different parameters involved in skin radiance and the global efficacy of the supplement.Results: Skin “red pink” and “olive” colors were significantly improved after supplementation (P<0.0001. Luminosity was increased by 25.9% (P<0.0001 whereas brightness and transparency were not affected by the supplementation. Facial skin imperfections were significantly reduced after the antioxidant-rich formulation intake (global reduction: –18.0%; P<0.0001. Indeed, dark circles, redness, and spots significantly diminished after oral treatment. Firmness and elasticity have been shown to be improved. Subjects were globally satisfied by the product (82.4% and have found improvements on their facial skin. Furthermore, 64.7% reported to look

  3. Sagging Skin

    Science.gov (United States)

    ... Skin Scars Skin Growths Skin Lesions Spider Veins Stretch Marks Sun-damaged Skin Unwanted Hair Unwanted Tattoos Varicose ... Skin Scars Skin Growths Skin Lesions Spider Veins Stretch Marks Sun-damaged Skin Unwanted Hair Unwanted Tattoos Varicose ...

  4. The moisturizing effects of glycolipid biosurfactants, mannosylerythritol lipids, on human skin.

    Science.gov (United States)

    Yamamoto, Shuhei; Morita, Tomotake; Fukuoka, Tokuma; Imura, Tomohiro; Yanagidani, Shusaku; Sogabe, Atsushi; Kitamoto, Dai; Kitagawa, Masaru

    2012-01-01

    Glycolipid biosurfactants, such as mannosylerythritol lipids (MELs), are produced by different yeasts belonging to the genus Pseudozyma and have been attracting much attention as new cosmetic ingredients owing to their unique liquid-crystal-forming and moisturizing properties. In this study, the effects of different MEL derivatives on the skin were evaluated in detail using a three-dimensional cultured human skin model and an in vivo human study. The skin cells were cultured and treated with sodium dodecyl sulfate (SDS), and the effects of different lipids on the SDS-damaged cells were evaluated on the basis of cell viability. Most MEL derivatives efficiently recovered the viability of the cells and showed high recovery rates (over 80%) comparable with that of natural ceramide. It is interesting that the recovery rate with MEL-A prepared from olive oil was significantly higher than that of MEL-A prepared from soybean oil. The water retention properties of MEL-B were further investigated on human forearm skin in a preliminary study. Compared with the control, the aqueous solution of MEL-B (5 wt%) was estimated to considerably increase the stratum corneum water content in the skin. Moreover, perspiration on the skin surface was clearly suppressed by treatment with the MEL-B solution. These results suggest that MELs are likely to exhibit a high moisturizing action, by assisting the barrier function of the skin. Accordingly, the yeast glycolipids have a strong potential as a new ingredient for skin care products.

  5. Experimental investigation of system effects in stressed-skin elements

    DEFF Research Database (Denmark)

    Dela Stang, B.; Isaksson, T.; Hansson, M.

    What kind of behaviour can be expected from stressed-skin elements at failure? To answer this question was a primary objective of the experimental investigation presented in this report. Systems of 3 roof units, each made of 5 parallel beams, have been tested for load-carrying capacity...

  6. Skin Cancer, Irradiation, and Sunspots: The Solar Cycle Effect

    Directory of Open Access Journals (Sweden)

    Edward Valachovic

    2014-01-01

    Full Text Available Skin cancer is diagnosed in more than 2 million individuals annually in the United States. It is strongly associated with ultraviolet exposure, with melanoma risk doubling after five or more sunburns. Solar activity, characterized by features such as irradiance and sunspots, undergoes an 11-year solar cycle. This fingerprint frequency accounts for relatively small variation on Earth when compared to other uncorrelated time scales such as daily and seasonal cycles. Kolmogorov-Zurbenko filters, applied to the solar cycle and skin cancer data, separate the components of different time scales to detect weaker long term signals and investigate the relationships between long term trends. Analyses of crosscorrelations reveal epidemiologically consistent latencies between variables which can then be used for regression analysis to calculate a coefficient of influence. This method reveals that strong numerical associations, with correlations >0.5, exist between these small but distinct long term trends in the solar cycle and skin cancer. This improves modeling skin cancer trends on long time scales despite the stronger variation in other time scales and the destructive presence of noise.

  7. RANDOM MICROSTRUCTURE FINITE ELEMENT METHOD FOR EFFECTIVE NONLINEAR PROPERTIES OF COMPOSITE MATERIALS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Some theoretical methods have been reported to deal with nonlinear problems of composite materials but the accuracy is not so good. In the meantime, a lot of nonlinear problems are difficult to be managed by the theoretical methods. The present study aims to use the developed method, the random microstructure finite element method, to deal with these nonlinear problems. In this paper, the random microstructure finite element method is used to deal with all three kinds of nonlinear property problems of composite materials. The analyzed results suggest that the influences of the nonlinear phenomena on the effective properties of composite materials are significant and the random microstructure finite element method is an efficient tool to investigate the nonlinear problems.

  8. An effective analytic approach for solving nonlinear fractional partial differential equations

    Science.gov (United States)

    Ma, Junchi; Zhang, Xiaolong; Liang, Songxin

    2016-08-01

    Nonlinear fractional differential equations are widely used for modelling problems in applied mathematics. A new analytic approach with two parameters c1 and c2 is first proposed for solving nonlinear fractional partial differential equations. These parameters are used to improve the accuracy of the resulting series approximations. It turns out that much more accurate series approximations are obtained by choosing proper values of c1 and c2. To demonstrate the applicability and effectiveness of the new method, two typical fractional partial differential equations, the nonlinear gas dynamics equation and the nonlinear KdV-Burgers equation, are solved.

  9. Effect of the counter cation on the third order nonlinearity in anionic Au dithiolene complexes

    Science.gov (United States)

    Iliopoulos, K.; El-Ghayoury, A.; Derkowska, B.; Ranganathan, A.; Batail, P.; Gindre, D.; Sahraoui, B.

    2012-12-01

    In this work, we present the third order nonlinear optical investigation of two gold complexes, which differ by the nature of the counter cations. The impact of the different design in the architecture through a set of hydrogen bonds in the case of Au-Mel of the systems on the nonlinearity has been studied by means of the Z-scan setup under 532 nm, 30 ps laser excitation, allowing for the determination of the nonlinear absorption and refraction of the samples. Significant modification of the nonlinear optical response between the two metal complexes has been found suggesting a clear effect of the counter cation.

  10. Limiting effects of geometrical and optical nonlinearities on the squeezing in optomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Djorwé, P. [Laboratory of Modelling and Simulation in Engineering, Biomimetics and Prototypes, Faculty of Science, University of Yaoundé I (Cameroon); Nana Engo, S.G., E-mail: nanaengo@gmail.com [Laboratory of Photonics, Faculty of Science, University of Ngaoundéré (Cameroon); Talla Mbé, J.H.; Woafo, P. [Laboratory of Modelling and Simulation in Engineering, Biomimetics and Prototypes, Faculty of Science, University of Yaoundé I (Cameroon)

    2013-08-01

    In recent experiments, the re-thermalization time of the mechanical resonator is stated as the limiting factor for quantum applications of optomechanical systems. To explain the origin of this limitation, an analytical nonlinear investigation supported by the recent successful experimental laser cooling parameters is carried out in this work. To this end, the effects of geometrical and the optical nonlinearities on the squeezing are studied and are in a good agreement with the experimental results. It appears that highly squeezed state are generated where these nonlinearities are minimized and that high nonlinearities are limiting factors to reach the quantum ground state.

  11. Synergistic effect of low-frequency ultrasound and surfactants on skin permeability.

    Science.gov (United States)

    Tezel, Ahmet; Sens, Ashley; Tuchscherer, Joe; Mitragotri, Samir

    2002-01-01

    Low-frequency ultrasound (20 kHz) and surfactants have been individually shown to enhance transdermal drug transport. In this study, we investigated the synergistic effect of ultrasound and surfactants on transdermal drug delivery. Surfactants with different head group chemistries including anionic, cationic, and nonionic with varying tail lengths (8-16-carbon atoms) were studied. We found that surfactants possessing anionic and cationic head groups were more potent than those possessing nonionic head groups in increasing skin conductivity in the presence of ultrasound. Furthermore, for surfactants possessing the same head group, those with a 14-carbon tail length were found to be most effective in enhancing skin permeability. The data presented in this report show that ultrasound and surfactants synergistically enhance skin permeability. Two mechanisms are shown to play a role in this synergistic effect. First, ultrasound enhances surfactant delivery (enhanced delivery) into the skin and, second, ultrasound disperses surfactant (enhanced dispersion) within the skin. In general, surfactants that are potent enhancers by themselves are potent enhancers in the presence of ultrasound as well. We performed imaging experiments to assess the effect of ultrasound on delivery of a model permeant, sulforhodamine B, into the skin. These experiments show that ultrasound enhances surfactant delivery and dispersion in the skin.

  12. Nonlinear dynamics of wind waves: multifractal phase/time effects

    Directory of Open Access Journals (Sweden)

    R. H. Mellen

    1994-01-01

    Full Text Available In addition to the bispectral coherence method, phase/time analysis of analytic signals is another promising avenue for the investigation of phase effects in wind waves. Frequency spectra of phase fluctuations obtained from both sea and laboratory experiments follow an F-β power law over several decades, suggesting that a fractal description is appropriate. However, many similar natural phenomena have been shown to be multifractal. Universal multifractals are quantified by two additional parameters: the Lévy index 0 α 2 for the type of multifractal and the co-dimension 0 C1 1 for intermittence. The three parameters are a full statistical measure the nonlinear dynamics. Analysis of laboratory flume data is reported here and the results indicate that the phase fluctuations are 'hard multifractal' (α > 1. The actual estimate is close to the limiting value α = 2,  which is consistent with Kolmogorov's lognormal model for turbulent fluctuations. Implications for radar and sonar backscattering from the sea surface are briefly considered.

  13. Nonlinear turbulence models for predicting strong curvature effects

    Institute of Scientific and Technical Information of China (English)

    XU Jing-lei; MA Hui-yang; HUANG Yu-ning

    2008-01-01

    Prediction of the characteristics of turbulent flows with strong streamline curvature, such as flows in turbomachines, curved channel flows, flows around airfoils and buildings, is of great importance in engineering applicatious and poses a very practical challenge for turbulence modeling. In this paper, we analyze qualitatively the curvature effects on the structure of turbulence and conduct numerical simulations of a turbulent U- duct flow with a number of turbulence models in order to assess their overall performance. The models evaluated in this work are some typical linear eddy viscosity turbulence models, nonlinear eddy viscosity turbulence models (NLEVM) (quadratic and cubic), a quadratic explicit algebraic stress model (EASM) and a Reynolds stress model (RSM) developed based on the second-moment closure. Our numerical results show that a cubic NLEVM that performs considerably well in other benchmark turbulent flows, such as the Craft, Launder and Suga model and the Huang and Ma model, is able to capture the major features of the highly curved turbulent U-duct flow, including the damping of turbulence near the convex wall, the enhancement of turbulence near the concave wall, and the subsequent turbulent flow separation. The predictions of the cubic models are quite close to that of the RSM, in relatively good agreement with the experimental data, which suggests that these inodels may be employed to simulate the turbulent curved flows in engineering applications.

  14. Stochastic nonlinear mixed effects: a metformin case study.

    Science.gov (United States)

    Matzuka, Brett; Chittenden, Jason; Monteleone, Jonathan; Tran, Hien

    2016-02-01

    In nonlinear mixed effect (NLME) modeling, the intra-individual variability is a collection of errors due to assay sensitivity, dosing, sampling, as well as model misspecification. Utilizing stochastic differential equations (SDE) within the NLME framework allows the decoupling of the measurement errors from the model misspecification. This leads the SDE approach to be a novel tool for model refinement. Using Metformin clinical pharmacokinetic (PK) data, the process of model development through the use of SDEs in population PK modeling was done to study the dynamics of absorption rate. A base model was constructed and then refined by using the system noise terms of the SDEs to track model parameters and model misspecification. This provides the unique advantage of making no underlying assumptions about the structural model for the absorption process while quantifying insufficiencies in the current model. This article focuses on implementing the extended Kalman filter and unscented Kalman filter in an NLME framework for parameter estimation and model development, comparing the methodologies, and illustrating their challenges and utility. The Kalman filter algorithms were successfully implemented in NLME models using MATLAB with run time differences between the ODE and SDE methods comparable to the differences found by Kakhi for their stochastic deconvolution.

  15. Nonlinear effects in a conceptual multilayer cloud model

    Directory of Open Access Journals (Sweden)

    U. Wacker

    2006-01-01

    Full Text Available As conceptual model for a cloud a system is considered which is open for condensate mass transport and subject to internal processes such as cloud microphysical transformation and vertical condensate transport. The effects of microphysical processes are represented in parameterized form and the system is divided into two layers to account for the vertical structure. The evolution is mathematically described in terms of four coupled nonlinear ODEs; the prognostic variables are the mass concentrations of cloud water as well as precipitation condensate in each of the layers. In the absence of vertical velocity the evolution in the lower layer is triggered by the evolution in the upper layer. In the presence of an upwind, the dynamics in both layers is mutually coupled. Depending on the chosen parameter values up to four steady states are found. When varying the parameter upwind velocity, three regimes are distinguished: For week upwind the long-term evolution is steered by the external sources; for stronger upwind the cloud condensate is blown out of the cloud in the final state and does not contribute to formation of precipitation; for intermediate upwind multiple steady state solution branches arise which characterize the transition between those two regimes.

  16. Weak nonlinear surface-charging effects in electrolytic films.

    Science.gov (United States)

    Dean, D S; Horgan, R R

    2003-11-01

    A simple model of soap films with nonionic surfactants stabilized by added electrolyte is studied. The model exhibits charge regularization due to the incorporation of a physical mechanism responsible for the formation of a surface charge. We use a Gaussian field theory in the film but the full nonlinear surface terms which are then treated at a one-loop level by calculating the mean-field Poisson-Boltzmann solution and then the fluctuations about this solution. We carefully analyze the renormalization of the theory and apply it to a triple-layer model for a thin film with Stern layer of thickness h. For this model we give expressions for the surface charge sigma(L) and the disjoining pressure P(d)(L) and show their dependence on the parameters. The influence of image charges naturally arises in the formalism, and we show that predictions depend strongly on h because of their effects. In particular, we show that the surface charge vanishes as the film thickness L-->0. The fluctuation terms in this class of theories contribute a Casimir-like attraction across the film. Although this attraction is well known to be negligible compared with the mean-field component for model electrolytic films with no surface-charge regulation, in the model studied here these fluctuations also affect the surface-charge regulation leading to a fluctuation component in the disjoining pressure which has the same behavior as the mean-field component even for large film thickness.

  17. Assessing the impacts of lifetime sun exposure on skin damage and skin aging using a non-invasive method

    Energy Technology Data Exchange (ETDEWEB)

    Kimlin, Michael G., E-mail: m.kimlin@qut.edu.au; Guo, Yuming, E-mail: guoyuming@yahoo.cn

    2012-05-15

    Background: Ultraviolet radiation exposure during an individuals' lifetime is a known risk factor for the development of skin cancer. However, less evidence is available on assessing the relationship between lifetime sun exposure and skin damage and skin aging. Objectives: This study aims to assess the relationship between lifetime sun exposure and skin damage and skin aging using a non-invasive measure of exposure. Methods: We recruited 180 participants (73 males, 107 females) aged 18-83 years. Digital imaging of skin hyperpigmentation (skin damage) and skin wrinkling (skin aging) on the facial region was measured. Lifetime sun exposure (presented as hours) was calculated from the participants' age multiplied by the estimated annual time outdoors for each year of life. We analyzed the effects of lifetime sun exposure on skin damage and skin aging. We adjust for the influence of age, sex, occupation, history of skin cancer, eye color, hair color, and skin color. Results: There were non-linear relationships between lifetime sun exposure and skin damage and skin aging. Younger participant's skin is much more sensitive to sun exposure than those who were over 50 years of age. As such, there were negative interactions between lifetime sun exposure and age. Age had linear effects on skin damage and skin aging. Conclusion: The data presented showed that self reported lifetime sun exposure was positively associated with skin damage and skin aging, in particular, the younger people. Future health promotion for sun exposure needs to pay attention to this group for skin cancer prevention messaging. - Highlights: Black-Right-Pointing-Pointer This is the first study finding the non-linear relationship between lifetime sun exposure and skin damage and skin aging. Black-Right-Pointing-Pointer This study finds there is negative interaction between lifetime sun exposure and age for skin damage and aging. Black-Right-Pointing-Pointer This study suggests that future

  18. Hairy skin exposure to VX in vitro: effectiveness of delayed decontamination.

    Science.gov (United States)

    Rolland, P; Bolzinger, M-A; Cruz, C; Josse, D; Briançon, S

    2013-02-01

    The chemical warfare agents such as VX represent a threat for both military and civilians, which involves an immediate need of effective decontamination systems. Since human scalp is usually unprotected compared to other body regions covered with clothes, it could be a preferential site of exposure in case of terrorist acts. The purpose of this study was to determine if skin decontamination could be efficient when performed more than 1h after exposure. In addition, the impact of hairs in skin contamination was investigated. By using in vitro skin models, we demonstrated that about 75% of the applied quantity of VX was recovered on the skin surface 2h after skin exposition, which means that it is worth decontaminating even if contamination occurred 2h before. The stratum corneum reservoir for VX was quickly established and persistent. In addition, the presence of hairs modified the percutaneous penetration of the nerve agent by binding of VX to hairs. Hair shaft has thus to be taken into account in the decontamination process. Reactive Skin Decontamination Lotion (RSDL) and Fuller's Earth (FE) were active in the skin decontamination 45min post-exposure, but RSDL was more efficient in reducing the amount of VX either in the skin or in the hair.

  19. Anti sense and sensibility : renal and skin effects of (antisense) oligonucleotides

    NARCIS (Netherlands)

    Meer, van L.

    2017-01-01

    This thesis describes the clinical investigation of a novel treatment strategy for type 2 diabetes mellitus (t2dm) using an antisense oligonucleotide(aon)to inhibit the sglt2 receptor. Furthermore it describes skin effects of oligonucleotides

  20. The effect of dietary and/or cosmetic argan oil on postmenopausal skin elasticity

    Directory of Open Access Journals (Sweden)

    Qiraouani Boucetta K

    2015-01-01

    Full Text Available Kenza Qiraouani Boucetta,1 Zoubida Charrouf,2 Hassan Aguenaou,3 Abdelfattah Derouiche,4 Yahya Bensouda1 1Research Team on Formulation and Biopharmacy, Research Center for Drug, Faculty of Medicine and Pharmacy, Mohammed V University, Rabat, Morocco; 2Faculty of Sciences, Mohammed V University, Rabat, Morocco; 3Mixed Unit of Research in Nutrition, ITU / CNESTEN, Ibn Tofail University, Kenitra, Morocco; 4Faculty of Sciences, Hassan II University, Casablanca, Morocco Background: During menopause, the decrease of estrogenic secretion induces the disruption of skin functioning, thus causing the decline in skin elasticity characteristic of skin aging. The purpose of this study was to evaluate in postmenopausal women the effect of daily consumption and/or application of argan oil on skin elasticity.Materials and methods: Sixty postmenopausal women consumed butter during the stabilization period and were randomly divided into two groups for the intervention period: the treatment group of 30 participants received dietary argan oil, the control group of 30 participants received olive oil, and both groups applied cosmetic argan oil in the left volar forearm during a 60-day period. Assessments of skin elasticity parameters, ie, the three R-parameters (R2 or gross-elasticity of the skin, R5 or net elasticity of the skin, and R7 or biological elasticity, and the resonance running time (RRT at both volar forearms of the two groups were performed during three visits: before starting oils consumption and application, after 30 days of oils consumption and application, and after 60 days of oils consumption and application.Results: The consumption of argan oil led to a significant increase of gross-elasticity of the skin (R2 (P<0.001, net elasticity of the skin (R5 (P<0.001, biological elasticity (R7 (P<0.001, and a significant decrease of RRT (P=0.002. The application of argan oil led to a significant increase of gross-elasticity of the skin (R2 (P<0.001, net

  1. Effects of water nanodroplets on skin moisture and viscoelasticity during air-conditioning.

    Science.gov (United States)

    Ohno, Hideo; Nishimura, Naoki; Yamada, Kuniyuki; Shimizu, Yuuki; Iwase, Satoshi; Sugenoya, Junichi; Sato, Motohiko

    2013-11-01

    In air-conditioned rooms, dry air exacerbates some skin diseases, for example, senile xerosis, atopic dermatitis, and surface roughness. Humidifiers are used to improve air dryness, which often induces excess humidity and thermal discomfort. To address this issue, we investigated the effects of water nanodroplets (mist) on skin hydration, which may increase skin hydration by penetrating into the interstitial spaces between corneocytes of the stratum corneum (SC) without increasing air humidity. We examined biophysical parameters, including skin conductance and transepidermal water loss (TEWL), and biomechanical parameters of skin distension/retraction before and after suction at the forehead, lateral canthus, and cheek, with or without mist, in a testing environment (24°C, 35% relative humidity) for 120 min. In the group without mist, TEWL values significantly decreased at all the sites after 1 h compared with the initial values. However, in the presence of mist, TEWL values were maintained at the initial values through the test, yielding significant differences vs. the group without mist. There were no significant differences between mist and mist-free groups in terms of skin conductance. Skin distension was significantly increased in the group with mist compared with that in the group without mist at the forehead and cheek, suggesting a softening effect of mist. Skin deformation of the face was improved by mist, suggesting hydration of the SC by mist. The change in TEWL was influenced by mist, suggesting supply of water to the skin, particularly the SC, by mist. These data indicated that a mist of water nanodroplets played an important role in softening skin in an air-conditioned room without increasing excess humidity. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Effects of a cellulose mask synthesized by a bacterium on facial skin characteristics and user satisfaction

    Directory of Open Access Journals (Sweden)

    Amnuaikit T

    2011-06-01

    Full Text Available Thanaporn Amnuaikit, Toon Chusuit, Panithi Raknam, Prapaporn BoonmeDepartment of Pharmaceutical Technology, Faculty of Pharmaceutical Sciences, Prince of Songkla University, Songkhla, ThailandBackground: Cellulose masks obtained from natural sources such as bacteria are of interest as cosmetic devices for the treatment of dry skin because they not only improve hydration of the skin, but have low toxicity and are biodegradable. The aims of this study were to determine the in vivo effects of a cellulose mask obtained from Acetobacter xylinum on skin characteristics and to evaluate user satisfaction with the product.Methods: Thirty healthy Thai volunteers aged 21–40 years participated in the study. The volunteers were randomly separated into a control group and an experimental group. For the control group, volunteers were assigned to apply moist towels to the face for 25 minutes. For the experimental group, the volunteers were assigned to apply the masks, ie, translucent patches which could be fitted onto the face for the same period. The following week, the groups were changed over to the alternative treatment. Skin moisture, sebum, elasticity, texture, dullness, and desquamation levels were assessed using a system used for routine skin counseling before applying the trial product and five minutes after its removal. Degree of satisfaction with use of the cellulose mask was investigated using a five-point rating scale.Results: The cellulose mask increased moisture levels in the skin significantly more than moist towels (P < 0.05 after a single application. No obvious effects on other skin characteristics were found. The cellulose mask product rated around 4/5 on the satisfaction rating scale.Conclusions: A single application of the trial cellulose mask enhanced moisture uptake by facial skin. Users also reported being satisfied with the trial product.Keywords: bacterial cellulose, facial mask, skin characteristics, skin hydration, user

  3. Effects of introducing nonlinear components for a random excited hybrid energy harvester

    Science.gov (United States)

    Zhou, Xiaoya; Gao, Shiqiao; Liu, Haipeng; Guan, Yanwei

    2017-01-01

    This work is mainly devoted to discussing the effects of introducing nonlinear components for a hybrid energy harvester under random excitation. For two different types of nonlinear hybrid energy harvesters subjected to random excitation, the analytical solutions of the mean output power, voltage and current are derived from Fokker-Planck (FP) equations. Monte Carlo simulation exhibits qualitative agreement with FP theory, showing that load values and excitation’s spectral density have an effect on the total mean output power, piezoelectric (PE) power and electromagnetic power. Nonlinear components affect output characteristics only when the PE capacitance of the hybrid energy harvester is non-negligible. Besides, it is also demonstrated that for this type of nonlinear hybrid energy harvesters under random excitation, introducing nonlinear components can improve output performances effectively.

  4. Effective Response of Nonlinear Composite under External AC and DC Electric Field

    Institute of Scientific and Technical Information of China (English)

    LIU Ye; LIANG Fang-Chu; SHEN Hong-Liang

    2005-01-01

    A perturbation method is used to study effective response of nonlinear Kerr composites, which are subject to the constitutive relation of electric displacement and electric field, Dα = εαE + xα|E|2E. Under the external AC and DC electric field Eapp = Eα(1 + sinwt), the effective nonlinear responses and local potentials are induced by the cubic nonlinearity of Kerr materials at all harmonics. As an example in three dimensions, we have investigated this kind of nonlinear composites with spherical inclusions embedded in a host. At all harmonic frequencies, the potentials in inclusion and host regions are derived. Furthermore, the formulae of the effective linear and nonlinear responses are given in the dilute limit.

  5. A nonlinear mixed-effects model for simultaneous smoothing and registration of functional data

    DEFF Research Database (Denmark)

    Raket, Lars Lau; Sommer, Stefan Horst; Markussen, Bo

    2014-01-01

    We consider misaligned functional data, where data registration is necessary for proper statistical analysis. This paper proposes to treat misalignment as a nonlinear random effect, which makes simultaneous likelihood inference for horizontal and vertical effects possible. By simultaneously fitting...

  6. Estimation of the Nonlinear Random Coefficient Model when Some Random Effects Are Separable

    Science.gov (United States)

    du Toit, Stephen H. C.; Cudeck, Robert

    2009-01-01

    A method is presented for marginal maximum likelihood estimation of the nonlinear random coefficient model when the response function has some linear parameters. This is done by writing the marginal distribution of the repeated measures as a conditional distribution of the response given the nonlinear random effects. The resulting distribution…

  7. Nonlinear effects in propagation of long-range surface plasmon polaritons in gold strip waveguides

    DEFF Research Database (Denmark)

    Lysenko, Oleg; Bache, Morten; Malureanu, Radu

    2016-01-01

    thickness. The theoretical model of these effects is based on the third-order susceptibility of the constituent materials. The linear and nonlinear parameters of the LRSPP mode are obtained, and the nonlinear Schrodinger equation is solved. The dispersion length is much larger than the waveguides length...

  8. Effective nonlinearities and multi-wavelength second-harmonic generation in modulated quasi-phase-matching gratings

    DEFF Research Database (Denmark)

    Bang, Ole; Graversen, T. W.; Clausen, Carl A. Balslev

    2000-01-01

    Quasi-phase-matching gratings induces Kerr effects in quadratic nonlinear materials. We show analytically and confirm numerically how modulating the grating changes the effective quadratic and cubic nonlinearities and allows for multi-wavelength second-harmonic generation....

  9. Parabens inhibit human skin estrogen sulfotransferase activity: possible link to paraben estrogenic effects.

    Science.gov (United States)

    Prusakiewicz, Jeffery J; Harville, Heather M; Zhang, Yanhua; Ackermann, Chrisita; Voorman, Richard L

    2007-04-11

    Parabens (p-hydroxybenzoate esters) are a group of widely used preservatives in topically applied cosmetic and pharmaceutical products. Parabens display weak associations with the estrogen receptors in vitro or in cell based models, but do exhibit estrogenic effects in animal models. It is our hypothesis that parabens exert their estrogenic effects, in part, by elevating levels of estrogens through inhibition of estrogen sulfotransferases (SULTs) in skin. We report here the results of a structure-activity-relationship of parabens as inhibitors of estrogen sulfation in human skin cytosolic fractions and normal human epidermal keratinocytes. Similar to reports of paraben estrogenicity and estrogen receptor affinity, the potency of SULT inhibition increased as the paraben ester chain length increased. Butylparaben was found to be the most potent of the parabens in skin cytosol, yielding an IC(50) value of 37+/-5 microM. Butylparaben blocked the skin cytosol sulfation of estradiol and estrone, but not the androgen dehydroepiandrosterone. The parabens were also tested as inhibitors of SULT activity in a cellular system, with normal human epidermal keratinocytes. The potency of butylparaben increased three-fold in these cells relative to the IC(50) value from skin cytosol. Overall, these results suggest chronic topical application of parabens may lead to prolonged estrogenic effects in skin as a result of inhibition of estrogen sulfotransferase activity. Accordingly, the skin anti-aging benefits of many topical cosmetics and pharmaceuticals could be derived, in part, from the estrogenicity of parabens.

  10. A novel administration route for edaravone: I. Effects of metabolic inhibitors on skin permeability of edaravone.

    Science.gov (United States)

    Sato, Toshiaki; Mizuno, Keizo; Ishii, Fumiyoshi

    2009-05-08

    We examined the effects of metabolic inhibitors on skin permeation of edaravone. SKF-525A, diclofenac sodium (DIC) and indomethacin (IND) were added to supernatant fluid (SF) of hairless rat (HR) skin homogenate. L-Cysteine (L-Cys) and benzotriazole (BTA), as pharmaceutical additives, were added to HR skin homogenate SF, and incubated at 37 degrees C for 30 min. K(m) and V(max) values were calculated. For determination of edaravone skin permeation from edaravone/hydroxypropyl-beta-cyclodextrin (HPbetaCD) complex solution, HR skin was placed in a Franz diffusion cell, and kept at 37 degrees C. Edaravone/HPbetaCD solution that contained L-Cys was put into the donor side. The relative activity in skin homogenate SF after co-treatment with IND and SKF-525A decreased to 40.8% of the control. However, DIC and IND had a weak inhibitory effect. For inhibition of edaravone metabolism, L-Cys and BTA had no effect on K(m) value, but V(max) was significantly decreased compared with controls (*P<0.05, Tukey-Kramer test). The edaravone skin permeation rate and permeability coefficient from edaravone/HPbetaCD complex solution with inhibitor were significantly increased compared with those without inhibitor. We suggest that the metabolism inhibitor was useful for the transdermal delivery of edaravone.

  11. DeoxyArbutin: a novel reversible tyrosinase inhibitor with effective in vivo skin lightening potency.

    Science.gov (United States)

    Boissy, Raymond E; Visscher, Marty; DeLong, Mitchell A

    2005-08-01

    Modulation of melanogenesis in the melanocytes can be achieved using chemicals that share structural homologies with the substrate tyrosine and as thus competitively inhibit the catalytic function of tyrosinase. We have developed a new tyrosinase inhibitor, deoxyArbutin (dA), based on this premise. DeoxyArbutin demonstrates effective inhibition of mushroom tyrosinase in vitro with a Ki that is 10-fold lower that hydroquinone (HQ) and 350-fold lower than arbutin. In a hairless, pigmented guinea pig model, dA demonstrated rapid and sustained skin lightening that was completely reversible within 8 weeks after halt in topical application. In contrast, HQ induced a short but unsustained skin lightening effect whereas kojic acid and arbutin exhibit no skin lightening effect. Results from a panel of safety tests supported the overall establishment of dA as an actionable molecule. In a human clinical trial, topical treatment of dA for 12 weeks resulted in a significant or slight reduction in overall skin lightness and improvement of solar lentigines in a population of light skin or dark skin individuals, respectively. These data demonstrate that dA has potential tyrosinase inhibitory activity that can result in skin lightening and may be used to ameliorate hyperpigmentary lesions.

  12. Influence of External Magnetic Field on Anomalous Skin Effects in Inductively Coupled Plasmas

    Institute of Scientific and Technical Information of China (English)

    MAO Ming; WANG You-Nian

    2004-01-01

    @@ Using a one-dimensional slab model, we study the influence of the external static magnetic field on the anomalous skin effects in the inductively coupled plasma. The rf electromagnetic field in the plasma is determined by solving the linearized Boltzmann equation incorporating with the Maxwell equations. The numerical results show that,due to the existence of the external magnetic field, the anomalous skin effects are greatly enhanced and the number of regions with negative absorption is decreased.

  13. The effect of Kinesiotaping to the skin temperature – Pilot study

    OpenAIRE

    Holma, Teemu

    2014-01-01

    Aim of this study was to research whether kinesiotape has effect to skin temperature. Subjects of this study were 32 asymptomatic students of Satakunta University of Applied Sciences, 20 females and 15 males. The exclusion criteria were: recent back pain or musculoskeletal diseases on back area skin irritations and diseases on taping site. To assess the effect of kinesiotape all the subjects were taped with 30 cm taped from Superios Posterios Iliac Spine(SPIS) upwards to the ribcage. Befo...

  14. Influence of thermal effects induced by nonlinear absorption on four-wave mixing in silicon waveguides

    DEFF Research Database (Denmark)

    Pu, Minhao; Chen, Yaohui; Yvind, Kresten

    2014-01-01

    Influence of thermal effects induced by nonlinear absorption on four-wave mixing in silicon waveguides is investigated. A conversion bandwidth reduction up to 63% is observed in simulation due to the thermal effects.......Influence of thermal effects induced by nonlinear absorption on four-wave mixing in silicon waveguides is investigated. A conversion bandwidth reduction up to 63% is observed in simulation due to the thermal effects....

  15. The biodisposition and hypertrichotic effects of bimatoprost in mouse skin.

    Science.gov (United States)

    Woodward, David F; Tang, Elaine S-H; Attar, Mayssa; Wang, Jenny W

    2013-02-01

    Studies on bimatoprost were performed with two objectives: (i) to determine whether bimatoprost possesses hair growth-stimulating properties beyond eyelash hypertrichosis and (ii) to investigate the biodisposition of bimatoprost in skin for the first time. Bimatoprost, at the dose used clinically for eyelash growth (0.03%) and given once daily for 14 days, increased pelage hair growth in C57/black 6 mice. This occurred as a much earlier onset of new hair growth in shaved mice and the time taken to achieve complete hair regrowth, according to photographic documentation and visual assessment. Bimatoprost biodisposition in the skin was determined at three concentrations: 0.01%, 0.03% and 0.06%. Dose-dependent C(max) values were obtained (3.41, 6.74, 12.3 μg/g tissue), and cutaneous bimatoprost was well maintained for 24 h following a single dose. Bimatoprost was recovered from the skin only as the intact molecule, with no detectable levels of metabolites. Thus, bimatoprost produces hypertrichosis as the intact molecule.

  16. Nonlinear effects in acoustic metamaterial based on a cylindrical pipe with ordered Helmholtz resonators

    Science.gov (United States)

    Lan, Jun; Li, Yifeng; Yu, Huiyang; Li, Baoshun; Liu, Xiaozhou

    2017-04-01

    We theoretically investigate the nonlinear effects of acoustic wave propagation and dispersion in a cylindrical pipe with periodically arranged Helmholtz resonators. By using the classical perturbation method in nonlinear acoustics and considering a nonlinear response up to the third-order at the fundamental frequency, the expressions of the nonlinear impedance ZNHR of the Helmholtz resonator and effective nonlinear bulk modulus Bneff of the composite structure are derived. In order to confirm the nonlinear properties of the acoustic metamaterial, the transmission spectra have been studied by means of the acoustic transmission line method. Moreover, we calculate the effective acoustic impedance and dispersion relation of the system using the acoustic impedance theory and Bloch theory, respectively. It is found that with the increment of the incident acoustic pressure level, owing to the nonlinearity of the Helmholtz resonators, the resonant frequency ω0 shifts toward the lower frequency side and the forbidden bandgap of the transmission spectrum is shown to be broadened. The perturbation method employed in this paper extends the general analytical framework for a nonlinear acoustic metamaterial.

  17. Extended Elliptic Mild Slope Equation Incorporating the Nonlinear Shoaling Effect

    Directory of Open Access Journals (Sweden)

    Xiao Qian-lu

    2016-10-01

    Full Text Available The transformation during wave propagation is significantly important for the calculations of hydraulic and coastal engineering, as well as the sediment transport. The exact wave height deformation calculation on the coasts is essential to near-shore hydrodynamics research and the structure design of coastal engineering. According to the wave shoaling results gained from the elliptical cosine wave theory, the nonlinear wave dispersion relation is adopted to develop the expression of the corresponding nonlinear wave shoaling coefficient. Based on the extended elliptic mild slope equation, an efficient wave numerical model is presented in this paper for predicting wave deformation across the complex topography and the surf zone, incorporating the nonlinear wave dispersion relation, the nonlinear wave shoaling coefficient and other energy dissipation factors. Especially, the phenomenon of wave recovery and second breaking could be shown by the present model. The classical Berkhoff single elliptic topography wave tests, the sinusoidal varying topography experiment, and complex composite slopes wave flume experiments are applied to verify the accuracy of the calculation of wave heights. Compared with experimental data, good agreements are found upon single elliptical topography and one-dimensional beach profiles, including uniform slope and step-type profiles. The results indicate that the newly-developed nonlinear wave shoaling coefficient improves the calculated accuracy of wave transformation in the surf zone efficiently, and the wave breaking is the key factor affecting the wave characteristics and need to be considered in the nearshore wave simulations.

  18. Reduced Noise Effect in Nonlinear Model Estimation Using Multiscale Representation

    Directory of Open Access Journals (Sweden)

    Mohamed N. Nounou

    2010-01-01

    Full Text Available Nonlinear process models are widely used in various applications. In the absence of fundamental models, it is usually relied on empirical models, which are estimated from measurements of the process variables. Unfortunately, measured data are usually corrupted with measurement noise that degrades the accuracy of the estimated models. Multiscale wavelet-based representation of data has been shown to be a powerful data analysis and feature extraction tool. In this paper, these characteristics of multiscale representation are utilized to improve the estimation accuracy of the linear-in-the-parameters nonlinear model by developing a multiscale nonlinear (MSNL modeling algorithm. The main idea in this MSNL modeling algorithm is to decompose the data at multiple scales, construct multiple nonlinear models at multiple scales, and then select among all scales the model which best describes the process. The main advantage of the developed algorithm is that it integrates modeling and feature extraction to improve the robustness of the estimated model to the presence of measurement noise in the data. This advantage of MSNL modeling is demonstrated using a nonlinear reactor model.

  19. Effects of quadratic and cubic nonlinearities on a perfectly tuned parametric amplifier

    Science.gov (United States)

    Neumeyer, S.; Sorokin, V. S.; Thomsen, J. J.

    2017-01-01

    We consider the performance of a parametric amplifier with perfect tuning (two-to-one ratio between the parametric and direct excitation frequencies) and quadratic and cubic nonlinearities. A forced Duffing-Mathieu equation with appended quadratic nonlinearity is considered as the model system, and approximate analytical steady-state solutions and corresponding stabilities are obtained by the method of varying amplitudes. Some general effects of pure quadratic, and mixed quadratic and cubic nonlinearities on parametric amplification are shown. In particular, the effects of mixed quadratic and cubic nonlinearities may generate additional amplitude-frequency solutions. In this case an increased response and a more phase sensitive amplitude (phase between excitation frequencies) is obtained, as compared to the case with either pure quadratic or cubic nonlinearity. Furthermore, jumps and bi-stability in the amplitude-phase characteristics are predicted, supporting previously reported experimental observations.

  20. Discriminating thermal effect in nonlinear-ellipse-rotation-modified Z-scan measurements.

    Science.gov (United States)

    Liu, Zhi-Bo; Shi, Shuo; Yan, Xiao-Qing; Zhou, Wen-Yuan; Tian, Jian-Guo

    2011-06-01

    We report that a modified Z-scan method by nonlinear ellipse rotation (NER) can be used to discriminate true nonlinear refraction from thermal effect in the transient regime and steady state. The combination of Z-scan and NER allows us to measure the third-order nonlinear susceptibility component without the influence of thermal-optical nonlinearity. The experimental results of pure CS(2) and CS(2) solutions of nigrosine verify that the transient thermal effect can be successfully eliminated from the NER-modified Z-scan measurements. This method is also extended to the case in which thermal-optical nonlinearities depend on a high repetition rate of femtosecond laser pulses for the N,N-dimethylmethanamide solutions of graphene oxide. © 2011 Optical Society of America

  1. Soliton Properties of Light Pulses on the Surface of Ionic Crystals Generated by Strong Nonlinear Effects

    Institute of Scientific and Technical Information of China (English)

    NIU Jia-Sheng; MA Ben-Kun

    2003-01-01

    In this paper, we theoretically discuss the soliton properties of light pulse transportation on the surface of an ionic crystal having strong nonlinear interactions between ions of unit cells. We analyze in detail the dark solitons when the nonlinear coefficient g is positive and negative, respectively. It is found that whether the nonlinear coefficient g is positive or negative, the dark solitons can be formed over the whole dispersion relation area of surface polaritons considering nonlinear effects. Attention should be paid to the fact that around ωTO, the light pulse can form advanced dark solitons, and there is a switching area from advanced dark soliton to retarded dark soliton near ωTO. We also discuss the effects of higher nonlinear dispersion on the solitons.

  2. Nonlinear optical and magneto-optical effects in non-spherical magnetic granular composite

    Institute of Scientific and Technical Information of China (English)

    Ping Xu(须萍); Zhenya Li(李振亚)

    2004-01-01

    The magnetization-induced nonlinear optical and nonlinear magneto-optical properties in a magnetic metal-insulator composite are studied based on a tensor effective medium approximation with shape factor and Taylcr-expansion method. There is a weakly nonlinear relation between electric displacement D and elcctric field E in the composite. The results of our studies on the effective dielectric tensor and the nonlinear susceptibility tensor in a magnetic nanocomposite are surveyed. It is shown that such a metal-insulator composite exhibits the enhancements of optical and magneto-optical nonlinearity. The frequencies at which the enhancements occur, and the amplitude of the enhancement factors depend on the concentration and shape of the magnetic grains.

  3. Nonlinear effects of the finite amplitude ultrasound wave in biological tissues

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Nonlinear effects will occur during the transmission of the finite amplitude wave in biological tissues.The theoretical prediction and experimental demonstration of the nonlinear effects on the propagation of the finite amplitude wave at the range of biomedical ultrasound frequency and intensity are studied.Results show that the efficiency factor and effective propagation distance will decrease while the attenuation coefficient increases due to the existence of nonlinear effects.The experimental results coincided quite well with the theory.This shows that the effective propagation distance and efficiency factor can be used to describe quantitatively the influence of nonlinear effects on the propagation of the finite amplitude sound wave in biological tissues.

  4. Using strong nonlinearity and high-frequency vibrations to control effective properties of discrete elastic waveguides

    DEFF Research Database (Denmark)

    Lazarov, Boyan Stefanov; Thomsen, Jon Juel; Snaeland, Sveinn Orri

    2008-01-01

    The aim of this article is to investigate how highfrequency (HF) excitation, combined with strong nonlinear elastic material behavior, influences the effective material or structural properties for low-frequency excitation and wave propagation. The HF effects are demonstrated on discrete linear s...... spring-mass chains with non-linear inclusions. The presented analytical and numerical results suggest that the effective material properties can easily be altered by establishing finite amplitude HF standing waves in the non-linear regions of the chain....

  5. Cutaneous effects of topical indomethacin, an inhibitor of prostaglandin synthesis, on uv-damaged skin

    Energy Technology Data Exchange (ETDEWEB)

    Snyder, D.S.

    1975-05-01

    Topical application of a 2.5 percent indomethacin (IM) solution to the sunburned skin of humans and guinea pigs resulted in a marked decrease in ultraviolet light (UVL)-induced erythema. In humans, a decrease in skin temperature and hyperalgesia to near normal levels was also observed. Epidermal responses to UVL injury such as keratinocyte cell death and altered DNA synthesis proceeded unmodified by IM. Repeated applications of IM in the 48-hr period following UVL exposure did not improve upon the results obtained following a single treatment. Guinea-pig skin provides a relevant model system for evaluating the effects of topical nonsteroidal anti-inflammatory agents on sunburn. (auth)

  6. Design evaluation and optimisation in crossover pharmacokinetic studies analysed by nonlinear mixed effects models

    OpenAIRE

    Nguyen, Thu Thuy; Bazzoli, Caroline; Mentré, France

    2012-01-01

    International audience; Bioequivalence or interaction trials are commonly studied in crossover design and can be analysed by nonlinear mixed effects models as an alternative to noncompartmental approach. We propose an extension of the population Fisher information matrix in nonlinear mixed effects models to design crossover pharmacokinetic trials, using a linearisation of the model around the random effect expectation, including within-subject variability and discrete covariates fixed or chan...

  7. Flavanone silibinin treatment attenuates nitrogen mustard-induced toxic effects in mouse skin

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Anil K.; Tewari-Singh, Neera; Inturi, Swetha; Kumar, Dileep [Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 (United States); Orlicky, David J. [Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 (United States); Agarwal, Chapla [Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 (United States); White, Carl W. [Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO 80045USA (United States); Agarwal, Rajesh, E-mail: Rajesh.Agarwal@UCDenver.edu [Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO 80045 (United States)

    2015-05-15

    Currently, there is no effective antidote to prevent skin injuries by sulfur mustard (SM) and nitrogen mustard (NM), which are vesicating agents with potential relevance to chemical warfare, terrorist attacks, or industrial/laboratory accidents. Our earlier report has demonstrated the therapeutic efficacy of silibinin, a natural flavanone, in reversing monofunctional alkylating SM analog 2-chloroethyl ethyl sulfide-induced toxic effects in mouse skin. To translate this effect to a bifunctional alkylating vesicant, herein, efficacy studies were carried out with NM. Topical application of silibinin (1 or 2 mg) 30 min after NM exposure on the dorsal skin of male SKH-1 hairless mice significantly decreased NM-induced toxic lesions at 24, 72 or 120 h post-exposure. Specifically, silibinin treatment resulted in dose-dependent reduction of NM-induced increase in epidermal thickness, dead and denuded epidermis, parakeratosis and microvesication. Higher silibinin dose also caused a 79% and 51%reversal in NM-induced increases in myeloperoxidase activity and COX-2 levels, respectively. Furthermore, silibinin completely prevented NM-induced H2A.X phosphorylation, indicating reversal of DNA damage which could be an oxidative DNA damage as evidenced by high levels of 8-oxodG in NM-exposed mouse skin that was significantly reversed by silibinin. Together, these findings suggest that attenuation of NM-induced skin injury by silibinin is due to its effects on the pathways associated with DNA damage, inflammation, vesication and oxidative stress. In conclusion, results presented here support the optimization of silibinin as an effective treatment of skin injury by vesicants. - Highlights: • Silibinin treatment attenuated nitrogen mustard (NM)-induced skin injury. • Silibinin affects pathways associated with DNA damage, inflammation and vesication. • The efficacy of silibinin could also be associated with oxidative stress. • These results support testing and optimization of

  8. Skin moisturization and frictional effects of an emollient-treated menstrual pad with a foam core.

    Science.gov (United States)

    Farage, Miranda A; Berardesca, Enzo; Maibach, Howard

    2009-01-01

    The emollient-transfer and frictional effects of a new, emollient-treated menstrual pad were studied to examine potential skin moisturization. When pads were applied for 6 hours to the popliteal fossa (behind-the knee [BTK] test), 79 microg of emollient per cm(2) was transferred from the pad surface. When swiped across forearm skin in a controlled fashion, the emollient-treated pads, but not the conventional pads, caused a rise in the coefficient of skin friction, indirect evidence of skin moisturization. When irritant and sensory effects were assessed in the BTK protocol, the test pad was comparable with the commercial product currently considered to be "best-in-class" for softness.

  9. Prebiotic effects of almonds and almond skins on intestinal microbiota in healthy adult humans.

    Science.gov (United States)

    Liu, Zhibin; Lin, Xiuchun; Huang, Guangwei; Zhang, Wen; Rao, Pingfan; Ni, Li

    2014-04-01

    Almonds and almond skins are rich in fiber and other components that have potential prebiotic properties. In this study we investigated the prebiotic effects of almond and almond skin intake in healthy humans. A total of 48 healthy adult volunteers consumed a daily dose of roasted almonds (56 g), almond skins (10 g), or commercial fructooligosaccharides (8 g) (as positive control) for 6 weeks. Fecal samples were collected at defined time points and analyzed for microbiota composition and selected indicators of microbial activity. Different strains of intestinal bacteria had varying degrees of growth sensitivity to almonds or almond skins. Significant increases in the populations of Bifidobacterium spp. and Lactobacillus spp. were observed in fecal samples as a consequence of almond or almond skin supplementation. However, the populations of Escherichia coli did not change significantly, while the growth of the pathogen Clostridum perfringens was significantly repressed. Modification of the intestinal microbiota composition induced changes in bacterial enzyme activities, specifically a significant increase in fecal β-galactosidase activity and decreases in fecal β-glucuronidase, nitroreductase and azoreductase activities. Our observations suggest that almond and almond skin ingestion may lead to an improvement in the intestinal microbiota profile and a modification of the intestinal bacterial activities, which would induce the promotion of health beneficial factors and the inhibition of harmful factors. Thus we believe that almonds and almond skins possess potential prebiotic properties.

  10. Effect of skin hydration on the dynamics of fingertip gripping contact

    Science.gov (United States)

    André, T.; Lévesque, V.; Hayward, V.; Lefèvre, P.; Thonnard, J.-L.

    2011-01-01

    The dynamics of fingertip contact manifest themselves in the complex skin movements observed during the transition from a stuck state to a fully developed slip. While investigating this transition, we found that it depended on skin hydration. To quantify this dependency, we asked subjects to slide their index fingertip on a glass surface while keeping the normal component of the interaction force constant with the help of visual feedback. Skin deformation inside the contact region was imaged with an optical apparatus that allowed us to quantify the relative sizes of the slipping and sticking regions. The ratio of the stuck skin area to the total contact area decreased linearly from 1 to 0 when the tangential force component increased from 0 to a maximum. The slope of this relationship was inversely correlated to the normal force component. The skin hydration level dramatically affected the dynamics of the contact encapsulated in the course of evolution from sticking to slipping. The specific effect was to reduce the tendency of a contact to slip, regardless of the variations of the coefficient of friction. Since grips were more unstable under dry skin conditions, our results suggest that the nervous system responds to dry skin by exaggerated grip forces that cannot be simply explained by a change in the coefficient of friction. PMID:21490002

  11. Effect of Physical Nonlinearity on Local Buckling in Sandwich Beams

    NARCIS (Netherlands)

    Koissin, Vitaly; Shipsha, Andrey; Skvortsov, Vitaly

    2010-01-01

    This article deals with experimental, theoretical, and FE characterization of the local buckling in foam-core sandwich beams. In the theoretical approach, this phenomena is considered in a periodic formulation (unbounded wrinkle wave); a nonlinear stress—strain response of the face material is accou

  12. Nonlinear effective-medium theory of disordered spring networks.

    Science.gov (United States)

    Sheinman, M; Broedersz, C P; MacKintosh, F C

    2012-02-01

    Disordered soft materials, such as fibrous networks in biological contexts, exhibit a nonlinear elastic response. We study such nonlinear behavior with a minimal model for networks on lattice geometries with simple Hookian elements with disordered spring constant. By developing a mean-field approach to calculate the differential elastic bulk modulus for the macroscopic network response of such networks under large isotropic deformations, we provide insight into the origins of the strain stiffening and softening behavior of these systems. We find that the nonlinear mechanics depends only weakly on the lattice geometry and is governed by the average network connectivity. In particular, the nonlinear response is controlled by the isostatic connectivity, which depends strongly on the applied strain. Our predictions for the strain dependence of the isostatic point as well as the strain-dependent differential bulk modulus agree well with numerical results in both two and three dimensions. In addition, by using a mapping between the disordered network and a regular network with random forces, we calculate the nonaffine fluctuations of the deformation field and compare them to the numerical results. Finally, we discuss the limitations and implications of the developed theory.

  13. Effect of Physical Nonlinearity on Local Buckling in Sandwich Beams

    NARCIS (Netherlands)

    Koysin, V.; Shipsha, Andrey; Skvortsov, Vitaly

    2010-01-01

    This article deals with experimental, theoretical, and FE characterization of the local buckling in foam-core sandwich beams. In the theoretical approach, this phenomena is considered in a periodic formulation (unbounded wrinkle wave); a nonlinear stress—strain response of the face material is accou

  14. Neutron Skin Thickness of Nuclei and Effective Nucleon-Nucleon Interactions

    Institute of Scientific and Technical Information of China (English)

    LIU Min; WANG Ning; LI Zhu-Xia; WU Xi-Zhen

    2006-01-01

    @@ The Skyrme energy density functional is applied to study the ground state properties of a series of finite nuclei.The charge rms radii, neutron rms radii, and the neutron skin thickness for some nuclei are calculated and compared with the experimental data. The constraint on the effective interactions, especially, the density dependence of the isospin-dependent part of Skyrme interactions is extracted by the data of neutron skin thicknesses of 208 pb and isotopes of Sn.

  15. Effect of microscopic modeling of skin in electrical and thermal analysis of transcranial direct current stimulation

    Science.gov (United States)

    Gomez-Tames, Jose; Sugiyama, Yukiya; Laakso, Ilkka; Tanaka, Satoshi; Koyama, Soichiro; Sadato, Norihiro; Hirata, Akimasa

    2016-12-01

    Transcranial direct current stimulation (tDCS) is a neuromodulation scheme where a small current is delivered to the brain via two electrodes attached to the scalp. The electrode design is an important topic, not only as regards efficacy, but also from a safety perspective, as tDCS may be related to skin lesions that are sometimes observed after stimulation. Previous computational models of tDCS have omitted the effects of microscopic structures in the skin, and the different soak conditions of the electrodes, and model validation has been limited. In this study, multiphysics and multiscale analysis are proposed to demonstrate the importance of microscopic modeling of the skin, in order to clarify the effects of the internal electric field, and to examine temperature elevation around the electrodes. This novel microscopic model of the skin layer took into consideration the effect of saline/water penetration in hair follicles and sweat ducts on the field distribution around the electrodes. The temperature elevation in the skin was then computed by solving the bioheat equation. Also, a multiscale model was introduced to account for macroscopic and microscopic tissues of the head and skin, which was validated by measurement of the head resistance during tDCS. As a result, the electric field in the microscopic model of the skin was less localized when the follicles/ducts were filled with saline instead of hair or tap water. Temperature elevation was also lessened with saline, in comparison with other substances. Saline, which may penetrate the hair follicles and sweat ducts, suppressed the field concentration around the electrodes. For conventional magnitudes of current injection, and a head resistance of less than 10 kΩ, the temperature elevation in the skin when using saline-soaked electrodes was low, less than 0.1 °C, and unlikely to cause adverse thermal effects.

  16. Effective Third-Order Nonlinearities in Metallic Refractory Titanium Nitride Thin Films

    CERN Document Server

    Kinsey, Nathaniel; Courtwright, Devon; DeVault, Clayton; Bonner, Carl E; Gavrilenko, Vladimir I; Shalaev, Vladimir M; Hagan, David J; Van Stryland, Eric W; Boltasseva, Alexandra

    2015-01-01

    Nanophotonic devices offer an unprecedented ability to concentrate light into small volumes which can greatly increase nonlinear effects. However, traditional plasmonic materials suffer from low damage thresholds and are not compatible with standard semiconductor technology. Here we study the nonlinear optical properties in the novel refractory plasmonic material titanium nitride using the Z scan method at 1550 nm and 780 nm. We compare the extracted nonlinear parameters for TiN with previous works on noble metals and note a similarly large nonlinear optical response. However, TiN films have been shown to exhibit a damage threshold up to an order of magnitude higher than gold films of a similar thickness, while also being robust, cost-efficient, bio- and CMOS compatible. Together, these properties make TiN a promising material for metal-based nonlinear optics.

  17. Theoretical investigation on Raman induced Kerr effect spectroscopy in nonlinear confocal microscopy

    Institute of Scientific and Technical Information of China (English)

    Gun LiNa; TANG ZhiLie; XING Da

    2008-01-01

    The imaging theory of Raman induced Kerr effect spectroscopy (RIKES) in nonlinear confocal microscopy is presented in this paper. Three-dimensional point spread function (3D-PSF) of RIKES nonlinear confocal microscopy in isotropic media is derived with Fourier imaging theory and RIKES theory. The impact of nonlinear property of RIKES on the spatial resolution and imaging properties of confocal microscopy have been analyzed in detail. It is proved that RIKES nonlinear confocal microscopy can simultaneously provide more information than twophoton confocal microscopy concerning molecular vibration mode, vibration orientation and optically induced molecular reorientation, etc. It is shown that RIKES nonlinear confocal microscopy significantly enhances the spatial resolution and imaging quality of confocal microscopy and achieves much higher resolution than that of two-photon confocal microscopy.

  18. Theoretical investigation on Raman induced Kerr effect spectroscopy in nonlinear confocal microscopy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The imaging theory of Raman induced Kerr effect spectroscopy (RIKES) in nonlinear confocal microscopy is presented in this paper. Three-dimensional point spread function (3D-PSF) of RIKES nonlinear confocal microscopy in isotropic media is derived with Fourier imaging theory and RIKES theory. The impact of nonlinear property of RIKES on the spatial resolution and imaging properties of confocal microscopy have been analyzed in detail. It is proved that RIKES nonlinear confocal microscopy can simultaneously provide more information than two-photon confocal microscopy concerning molecular vibration mode, vibration orientation and optically induced molecular reorientation, etc. It is shown that RIKES nonlinear confocal microscopy significantly enhances the spatial resolution and imaging quality of confocal microscopy and achieves much higher resolution than that of two-photon confocal microscopy.

  19. Vibrations and spatial patterns in biomimetic surfaces: using the shark-skin effect to control blood clotting.

    Science.gov (United States)

    Ramachandran, Rahul; Maani, Nazanin; Rayz, Vitaliy L; Nosonovsky, Michael

    2016-08-01

    We study the effect of small-amplitude fast vibrations and small-amplitude spatial patterns on various systems involving wetting and liquid flow, such as superhydrophobic surfaces, membranes and flow pipes. First, we introduce a mathematical method of averaging the effect of small spatial and temporal patterns and substituting them with an effective force. Such an effective force can change the equilibrium state of a system as well as a phase state, leading to surface texture-induced and vibration-induced phase control. Vibration and patterns can effectively jam holes in vessels with liquid, separate multi-phase flow, change membrane properties, result in propulsion and locomotion and lead to many other multi-scale, nonlinear effects including the shark-skin effect. We discuss the application of such effects to blood flow for novel biomedical 'haemophobic' applications which can prevent blood clotting and thrombosis by controlling the surface pattern at a wall of a vessel (e.g. a catheter or stent).This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'.

  20. Calcipotriol delivery into the skin as emulgel for effective permeation.

    Science.gov (United States)

    Naga Sravan Kumar Varma, V; Maheshwari, P V; Navya, M; Reddy, Sharath Chandra; Shivakumar, H G; Gowda, D V

    2014-12-01

    The objective of this work is to formulate and evaluate an emulgel containing calcipotriol for treatment of psoriasis. Emulgels have emerged as a promising drug delivery system for the delivery of hydrophobic drugs. Isopropyl alcohol and polyethylene glycol have been employed as permeation enhancers. Formulation chart is made with seven formulations, evaluated for physical parameters, drug content, viscosity, thixotropy, spreadability, extrudability, mucoadhesion, diffusion studies, skin irritation test along with short term stability studies. Carbopolis is reported to have a direct influence on appearance and viscosity of final formulation. The photomicroscopic evaluations showed the presence of spherical globules in size range of 10-15 μm. Rheograms revealed that all the formulations exhibited pseudoplastic flow. Optimized formulation (F6) had shown 86.42 ± 2.0% drug release at the end of 8 h study. The release rate through dialysis membrane and rat skin is higher when compared to commercial calcipotriol ointment. Hence it is concluded that calcipotriol can be delivered topically with enhanced penetration properties when formulated as emulgel.

  1. Weakly nonlinear dispersion and stop-band effects for periodic structures

    DEFF Research Database (Denmark)

    Sorokin, Vladislav; Thomsen, Jon Juel

    Continua and structures composed of periodically repeated elements (cells) are used in many fields of science and technology. Examples of continua are composite materials, consisting of alternating volumes of substances with different properties, mechanical filters and wave guides. Examples of en...... suggested. The work is carried out with financial support from the Danish Council for Independent Research and COFUND: DFF – 1337-00026...... of these methods for studying nonlinear problems isimpossible or cumbersome, since Floquet theory is applicable only for linear systems. Thus the nonlinear effects for periodic structures are not yet fully uncovered, while at the same time applications may demand effects of nonlinearity on structural response...

  2. Using nonlinearity and spatiotemporal property modulation to control effective structural properties: dynamic rods

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel; Blekhman, Iliya I.

    2007-01-01

    , and to call these dynamic materials or spatiotemporal composites. Also, according to theoretical predictions, structural nonlinearity enhances the possibilities of achieving specific effective properties. For example, with an elastic rod having cubical elastic nonlinearities, it seems possible to control......, and exemplified. Then simple approximate analytical expressions are derived for the effective wave speed and natural frequencies for one-dimensional wave propagation in a nonlinear elastic rod, where the spatiotemporal modulation is imposed as a high-frequency standing wave, supposed to be given. Finally the more...

  3. Beneficial effects of pro-/antioxidant-based nutraceuticals in the skin rejuvenation techniques.

    Science.gov (United States)

    de Luca, C; Deeva, I; Mikhal'Chik, E; Korkina, L

    2007-04-15

    Modern technologies of skin rejuvenation include many physical and chemical intervention tools--laser irradiation, oxygen and ozone therapy, chemical peels, plastic surgery operations--affecting by different mechanisms the sensitive physiological free radical/antioxidant balance in the skin. All these interventions induce from mild to severe tissue damage, providing beneficial biochemical stimuli for skin re-epithelization and rejuvenation. Paradoxically, free radical production in the course of tissue inflammation helps to combat free radical damage consequent to the ageing process. We have studied two animal models (experimental burn and trichloracetic peeling), reproducing on the Wistar rat the effects generated by the commonly practiced aesthetic medicine procedures of laser resurfacing and chemical peels, demonstrating that the severe oxidative stress induced both systemically and on skin can be modulated by the oral pre- and post treatment administration of specific nutraceutical formulations. Potent antioxidants (RRR-alpha-tocopherol, coenzyme Q10), enhancing antioxidant defences, coupled with mild pro-oxidants, enhancers of a specific immune defense (soy phospholipids, L-methionine), at the blood and the skin levels, proved in fact to be beneficial in vivo, on the rat, for skin healing, trophism and accelerated re-epithelization. Data obtained allow us to predict the possibility of innovative protocols for dermocosmetology, enabling successful lowering of the risk of permanent adverse effects, and prolonging the duration of the beneficial effects of dermocosmetologic procedures.

  4. Molecular mechanisms of green tea polyphenols with protective effects against skin photoaging.

    Science.gov (United States)

    Roh, Eunmiri; Kim, Jong-Eun; Kwon, Jung Yeon; Park, Jun Seong; Bode, Ann M; Dong, Zigang; Lee, Ki Won

    2017-05-24

    Whereas green tea has historically been consumed in high quantities in Northeast Asia, its popularity is also increasing in many Western countries. Green tea is an abundant source of plant polyphenols exhibiting numerous effects that are potentially beneficial for human health. Accumulating evidence suggests that green tea polyphenols confer protective effects on the skin against ultraviolet (UV) irradiation-induced acceleration of skin aging, involving antimelanogenic, antiwrinkle, antioxidant, and anti-inflammatory effects as well as prevention of immunosuppression. Melanin pigmentation in the skin is a major defense mechanism against UV irradiation, but pigmentation abnormalities such as melasma, freckles, senile lentigines, and other forms of melanin hyperpigmentation can also cause serious health and aesthetic issues. Furthermore, UV irradiation initiates the degradation of fibrillar collagen and elastic fibers, promoting the process of skin aging through deep wrinkle formation and loss of tissue elasticity. UV irradiation-induced formation of free radicals also contributes to accelerated photoaging. Additionally, immunosuppression caused by UV irradiation plays an important role in photoaging and skin carcinogenesis. In this review, we summarize the current literature regarding the antimelanogenic, antiwrinkle, antioxidant, and immunosuppression preventive mechanisms of green tea polyphenols that have been demonstrated to protect against UV irradiation-stimulated skin photoaging, and gauge the quality of evidence supporting the need for clinical studies using green tea polyphenols as anti-photoaging agents in novel cosmeceuticals.

  5. Nonlinear optical properties and optical power limiting effect of Giemsa dye

    Science.gov (United States)

    Al-Saidi, Imad Al-Deen Hussein A.; Abdulkareem, Saif Al-Deen

    2016-08-01

    The nonlinear optical properties of Giemsa dye in chloroform solution for different concentrations and dye mixed with poly(methylmethacrylate) (PMMA) as a dye-doped polymer film were investigated using continuous wave (CW) low power solid-state laser (SSL) operating at wavelength of 532 nm as an excitation source. Using the single beam z-scan technique, the nonlinear refractive index (n2), the nonlinear absorption coefficient (β), and the third-order nonlinear optical susceptibility (χ(3)) of Giemsa dye were measured. The measurements reveal that both n2 and β are dependent on the dye concentration. The obtained results indicate that the Giemsa dye exhibits positive nonlinear saturable absorption (SA) and negative refraction nonlinearity, manifestation of self-defocusing effect. Optical power limiting characteristics of the Giemsa dye at different concentrations in solution and polymer film were studied. The observed large third-order optical nonlinearity of Giemsa dye confirms that Giemsa dye is a promising nonlinear material for the optical power limiting and photonic devices applications.

  6. Effects of Prisma® Skin dermal regeneration device containing glycosaminoglycans on human keratinocytes and fibroblasts.

    Science.gov (United States)

    Belvedere, Raffaella; Bizzarro, Valentina; Parente, Luca; Petrella, Francesco; Petrella, Antonello

    2017-08-10

    Prisma® Skin is a new pharmaceutical device developed by Mediolanum Farmaceutici S.p.a. It includes alginates, hyaluronic acid and mainly mesoglycan. The latter is a natural glycosaminoglycan preparation containing chondroitin sulfate, dermatan sulfate, heparan sulfate and heparin and it is used in the treatment of vascular disease. Glycosaminoglycans may contribute to the re-epithelialization in the skin wound healing, as components of the extracellular matrix. Here we describe, for the first time, the effects of Prisma® Skin in in vitro cultures of adult epidermal keratinocytes and dermal fibroblasts. Once confirmed the lack of cytotoxicity by mesoglycan and Prisma® Skin, we have shown the increase of S and G2 phases of fibroblasts cell cycle distribution. We further report the strong induction of cell migration rate and invasion capability on both cell lines, two key processes of wound repair. In support of these results, we found significant cytoskeletal reorganization, following the treatments with mesoglycan and Prisma® Skin, as confirmed by the formation of F-actin stress fibers. Additionally, together with a significant reduction of E-cadherin, keratinocytes showed an increase of CD44 expression and the translocation of ezrin to the plasma membrane, suggesting the involvement of CD44/ERM (ezrin-radixin-moesin) pathway in the induction of the analyzed processes. Furthermore, as showed by immunofluorescence assay, fibroblasts treated with mesoglycan and Prisma® Skin exhibited the increase of Fibroblast Activated Protein α and a remarkable change in shape and orientation, two common features of reactive stromal fibroblasts. In all experiments Prisma® Skin was slightly more potent than mesoglycan. In conclusion, based on these findings we suggest that Prisma® Skin may be able to accelerate the healing process in venous skin ulcers, principally enhancing re-epithelialization and granulation processes.

  7. Properties of Differential Scattering Section Based on Multi-photon Nonlinear Compton Effect

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Properties of damping electrons in collision with photons based on multi-photon nonlinear Compton effect are investigated. The expressions of the differential scattering section are derived. Several useful conclusions are drawn.

  8. Systematic treatment of non-linear effects in Baryon Acoustic Oscillations

    CERN Document Server

    Ivanov, Mikhail M

    2016-01-01

    In this contribution we will discuss the non-linear effects in the baryon acoustic oscillations and present a systematic and controllable way to account for them within time-sliced perturbation theory.

  9. Diffraction corrections for second harmonic beam fields and effects on the nonlinearity parameter evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hyun Jo; Cho, Sung Jong; Nam, Ki Woong; Lee, Jang Hyun [Division of Mechanical and Automotive Engineering, Wonkwang University, Iksan (Korea, Republic of)

    2016-04-15

    The nonlinearity parameter is frequently measured as a sensitive indicator in damaged material characterization or tissue harmonic imaging. Several previous studies have employed the plane wave solution, and ignored the effects of beam diffraction when measuring the non-linearity parameter β. This paper presents a multi-Gaussian beam approach to explicitly derive diffraction corrections for fundamental and second harmonics under quasilinear and paraxial approximation. Their effects on the nonlinearity parameter estimation demonstrate complicated dependence of β on the transmitter-receiver geometries, frequency, and propagation distance. The diffraction effects on the non-linearity parameter estimation are important even in the nearfield region. Experiments are performed to show that improved β values can be obtained by considering the diffraction effects.

  10. Preconditioning of Nonlinear Mixed Effects Models for Stabilisation of Variance-Covariance Matrix Computations

    National Research Council Canada - National Science Library

    Aoki, Yasunori; Nordgren, Rikard; Hooker, Andrew C

    2016-01-01

    ... a bottleneck in the analysis. We propose a preconditioning method for non-linear mixed effects models used in pharmacometric analyses to stabilise the computation of the variance-covariance matrix...

  11. EFFECT OF DAMAGE ON NONLINEAR DYNAMIC PROPERTIES OF VISCOELASTIC RECTANGULAR PLATES

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yu-fang; FU Yi-ming

    2005-01-01

    The nonlinear dynamic behaviors of viscoelastic rectangular plates including the damage effects under the action of a transverse periodic load were studied. Using the von Karman equations, Boltzmann superposition principle and continuum damage mechanics, the nonlinear dynamic equations in terms of the mid-plane displacements for the viscoelastic thin plates with damage effect were derived. By adopting the finite difference method and Newmark method, these equations were solved. The results were compared with the available data. In the numerical calculations, the effects of the external loading parameters and geometric dimensions of the plate on the nonlinear dynamic responses of the plate were discussed. Research results show that the nonlinear dynamic response of the structure will change remarkably when the damage effect is considered.

  12. The effects of cyclic tensile and stress-relaxation tests on porcine skin.

    Science.gov (United States)

    Remache, D; Caliez, M; Gratton, M; Dos Santos, S

    2017-09-11

    When a living tissue is subjected to cyclic stretching, the stress-strain curves show a shift down with the increase in the number of cycles until stabilization. This phenomenon is referred to in the literature as a preconditioning and is performed to obtain repeatable and predictable measurements. Preconditioning has been routinely performed in skin tissue tests; however, its effects on the mechanical properties of the material such as viscoelastic response, tangent modulus, sensitivity to strain rate, the stress relaxation rate, etc….remain unclear. In addition, various physical interpretations of this phenomenon have been proposed and there is no general agreement on its origin at the microscopic or mesoscopic scales. The purpose of this study was to investigate the effect of the cyclical stretching and the stress-relaxation tests on the mechanical properties of the porcine skin. Cyclic uniaxial tensile tests at large and constant strain were performed on different skin samples. The change in the reaction force, and skin's tangent modulus as a function of the number of cycles, as well as the strain rate effect on the mechanical behavior of skin samples after cycling were investigated. Stress-relaxation tests were also performed on skin samples. The change in the reaction force as a function of relaxation time and the strain rate effect on the mechanical behavior of skin samples after the stress-relaxation were investigated. The mechanical behavior of a skin sample under stress-relaxation test was modeled using a combination of hyperelasticity and viscoelasticity. Overall, the results showed that the mechanical behavior of the skin was strongly influenced by cycling and stress relaxation tests. Indeed, it was observed that the skin's resistance decreased by about half for two hours of cycling; the tangent modulus degraded by nearly 30% and skin samples became insensitive to the strain rates and accumulated progressively an inelastic deformation over time during

  13. Examining the Error of Mis-Specifying Nonlinear Confounding Effect with Application on Accelerometer-Measured Physical Activity

    Science.gov (United States)

    Lee, Paul H.

    2017-01-01

    Purpose: Some confounders are nonlinearly associated with dependent variables, but they are often adjusted using a linear term. The purpose of this study was to examine the error of mis-specifying the nonlinear confounding effect. Methods: We carried out a simulation study to investigate the effect of adjusting for a nonlinear confounder in the…

  14. Effect of compositions in nanostructured lipid carriers (NLC) on skin hydration and occlusion

    Science.gov (United States)

    Loo, CH; Basri, M; Ismail, R; Lau, HLN; Tejo, BA; Kanthimathi, MS; Hassan, HA; Choo, YM

    2013-01-01

    Purpose To study the effects of varying lipid concentrations, lipid and oil ratio, and the addition of propylene glycol and lecithin on the long-term physical stability of nanostructured lipid nanocarriers (NLC), skin hydration, and transepidermal water loss. Methods The various NLC formulations (A1–A5) were prepared and their particle size, zeta potential, viscosity, and stability were analyzed. The formulations were applied on the forearms of the 20 female volunteers (one forearm of each volunteer was left untreated as a control). The subjects stayed for 30 minutes in a conditioned room with their forearms uncovered to let the skin adapt to the temperature (22°C ± 2°C) and humidity (50% ± 2%) of the room. Skin hydration and skin occlusion were recorded at day one (before treatment) and day seven (after treatment). Three measurements for skin hydration and skin occlusion were performed in each testing area. Results NLC formulations with the highest lipid concentration, highest solid lipid concentration, and additional propylene glycol (formulations A1, A2, and A5) showed higher physical stability than other formulations. The addition of propylene glycol into an NLC system helped to reduce the particle size of the NLC and enhanced its long-term physical stability. All the NLC formulations were found to significantly increase skin hydration compared to the untreated controls within 7 days. All NLC formulations exhibited occlusive properties as they reduced the transepidermal water loss within 7 days. This effect was more pronounced with the addition of propylene glycol or lecithin into an NLC formulation, whereby at least 60% reduction in transepidermal water loss was observed. Conclusion NLCs with high lipid content, solid lipid content, phospholipid, and lecithin are a highly effective cosmetic delivery system for cosmetic topical applications that are designed to boost skin hydration. PMID:23293516

  15. Comparison of skin effects of immediate treatment modalities in experimentally induced hydrofluoric acid skin burns.

    Science.gov (United States)

    Songur, Meltem K; Akdemir, Ovunc; Lineaweaver, William C; Cavusoglu, Turker; Ozsarac, Murat; Aktug, Huseyin; Songur, Ecmel; Tiftikcioglu, Yigit O

    2015-12-01

    Hydrofluoric acid (HF) burns cause immediate damage and painful long-term sequellae. Traditionally, chelating agents have been used as the initial treatment for such burns. We have introduced epidermal growth factor (EGF) into an HF model to compare EGF with Ca(2+) and Mg(2+) treatments; 40 Sprague Dawley rats were divided into five groups. Each rat suffered a 6 × 4 cm(2) burn induced by 40% HF. Group 1 had no treatment, group 2 had saline injected beneath the burn, group 3 received magnesium sulphate injections, group 4 received calcium gluconate and group 5 received EGF. Specimens were evaluated via planimetry and biopsy at intervals of 4, 8, 24 and 72 hours. Fluid losses were significantly less in the Mg(2+) and EGF groups. The EGF group had the smallest burn area, least oedema, least polymorphonuclear granulocyte (PMN) infiltration, most angiogenesis and highest fibroblast proliferation of any group (P < 0·005). EGF limited HF damage morphologically and histologically more effectively than Ca(2+) or Mg(2+). This finding indicates that HF treatment via growth factors may be an improvement over chelation therapy.

  16. Asymmetrically pumped Bragg scattering with the effects of nonlinear phase modulation

    DEFF Research Database (Denmark)

    Andersen, Lasse Mejling; Friis, Søren Michael Mørk; Reddy, Dileep V.

    2014-01-01

    We derive exact solutions to asymmetrically pumped Bragg scattering with nonlinear phase-modulation (NPM) and show that this setup allows for the frequency conversion of many temporal modes, while reducing the effects due to NPM.......We derive exact solutions to asymmetrically pumped Bragg scattering with nonlinear phase-modulation (NPM) and show that this setup allows for the frequency conversion of many temporal modes, while reducing the effects due to NPM....

  17. Nonlinear Effects in Quantum Dynamics of Atom Laser: Mean-Field Approach

    Institute of Scientific and Technical Information of China (English)

    JING Hui

    2002-01-01

    Quantum dynamics and statistics of an atom laser with nonlinear binary interactions are investigated inthe framework of mean-field approximation. The linearized effective Hamiltonian of the system is accurately solvable.It is shown that, although the input radio frequency field is in an ordinary Glauber coherent state, the output matterwave will periodically exhibit quadrature squeezing effects purely originated from the nonlinear atom-atom collisions.

  18. French Maritime Pine Bark Extract (Pycnogenol®) Effects on Human Skin: Clinical and Molecular Evidence.

    Science.gov (United States)

    Grether-Beck, Susanne; Marini, Alessandra; Jaenicke, Thomas; Krutmann, Jean

    2016-01-01

    Nutritional strategies to benefit skin health are of growing importance. Current approaches mainly involve nutritional supplements containing antioxidants which were initially designed to protect human skin against ultraviolet radiation-induced damage. Within recent years, however, a growing number of studies suggests that the beneficial effects of these products clearly extend beyond photoprotection. In this review we take the nutritional supplement Pycnogenol®, which is based on an extract prepared from French marine pine bark extract, as an example to illustrate this development. Accordingly, the existing data provide compelling evidence that Pycnogenol® intake does not only provide photoprotection, but may be used to (i) reduce hyperpigmentation of human skin and (ii) improve skin barrier function and extracellular matrix homeostasis.

  19. Effect of local application of superoxide dismutase on dielectric parameters of cooled skin in rats.

    Science.gov (United States)

    Paramonov, B A; Turkovski, I I; Doroshkevich, O S; Taranova, V N; Pomorski, K P

    2008-11-01

    The effect of on Changes in dielectric parameters of the skin (modulus of complex dielectric permittivity |e| and dielectric loss tangent tgd) were studied on rats with local surface contact cooling followed by treatment with various cream formulations. Addition of antioxidant superoxide dismutase (SOD) to the cream significantly prevented the shifts in these parameters, which attested to less pronounced changes in the water balance in SOD-treated skin. Application of SOD during the early terms after cooling accelerated wound healing. Histological examination performed on posttraumatic day 60 revealed better integrity of the skin structures (hair follicle, sweat and sebaceous gland), which indicates ability of SOD to prevent and ameliorate the degree of cold-induced damage in the skin.

  20. Antioxidant effects of an ozonized theobroma oil formulation on damaged-inflammatory rat skin

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Y.; Diaz, M.F.; Hernandez, F.; Gila, D.; Ga, G.

    2011-07-01

    The aim of this study was to determine whether a cosmetic formulation elaborated with ozonized theobroma oil may exert beneficial effects in the restoring of the antioxidant activity on the skin of rats previously irradiated with ultraviolet light. 0.5 g of the formulation was applied on the skin of rats for five days. Superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) activity were determined in a homogenate of rat skin. Malondialdehyde (MDA), conjugated dienes (CD) and total hydroperoxide (THP) content were determined as biomarkers of oxidative stress. Using these parameters, antioxidant and oxidant activity, redox index and oxidative stress grade were determined. The total antioxidant activity was significantly increased while the redox index, total oxidant activity and oxidative stress grade decreased significantly in damaged rats treated with the formulation. These results show the antioxidant properties of the cosmetic formulation due to the stimulation of antioxidant enzymes such as SOD and GPx, preventing skin injury induced by ultraviolet irradiation. (Author).

  1. Wound tension in rhytidectomy. Effects of skin-flap undermining and superficial musculoaponeurotic system suspension.

    Science.gov (United States)

    Burgess, L P; Casler, J D; Kryzer, T C

    1993-02-01

    This study was conducted to determine the effects of skin-flap undermining and superficial musculoaponeurotic system (SMAS) suspension on wound-closing tension. Nine sides from five fresh-frozen cadavers were used, with closing tension measured at the two main anchor points, anteriorly (A) and posteriorly (P), with and without SMAS plication for minimal (MIN), intermediate (INT), and maximal (MAX) skin-flap undermining. Results indicated that closing tension was significantly decreased with SMAS plication, both A and P, for all three levels of skin undermining. The average decrease in closing tension with SMAS plication was: A-MIN 191 g, A-INT 95 g, A-MAX 83 g, P-MIN 235 g, P-INT 68 g, and P-MAX 70 g (P tension decreased with wider skin-flap undermining, both with and without SMAS plication. The tension-reducing effect of SMAS plication was decreased with wider skin-flap undermining. Regression analysis determined a second-order exponential curve relating closing tension to skin excision.

  2. Effect of topical clay application on the synthesis of collagen in skin: an experimental study.

    Science.gov (United States)

    Valenti, D M Z; Silva, J; Teodoro, W R; Velosa, A P; Mello, S B V

    2012-03-01

    Clay is often used in cosmetic treatments, although little is known about its action. To evaluate the effect of topical clay application on the histoarchitecture of collagen fibres in rat skin. Animals received a daily application of clay and retinoic acid (RA) 0.025% to the dorsal skin over 7 and 14 days, under vaporization at 37 °C for 40 min. Control skin was not vaporized. Samples from each region were excised, and stained with picrosirius red for collagen evaluation. Seven days after clay treatment, an increase in the number of collagen fibres was observed in treated skin compared with control skin (51.74 ± 1.28 vs. 43.39 ± 1.79%, respectively, P Clay application over 14 days did not induce a further increase in skin collagen, whereas treatment with RA did (58.07 ± 1.59%; P = 0.001 vs. control). Clay application promotes an increase in the number of collagen fibres, which may account for its beneficial effects. © The Author(s). CED © 2012 British Association of Dermatologists.

  3. Nonlinear effects in propagation of long-range surface plasmon polaritons in gold strip waveguides

    Science.gov (United States)

    Lysenko, Oleg; Bache, Morten; Malureanu, Radu; Lavrinenko, Andrei

    2016-04-01

    This paper is devoted to experimental and theoretical studies of nonlinear propagation of a long-range surface plasmon polariton (LRSPP) in gold strip waveguides. The plasmonic waveguides are fabricated in house, and contain a gold layer, tantalum pentoxide adhesion layers, and silicon dioxide cladding. The optical characterization was performed using a high power picosecond laser at 1064 nm. The experiments reveal two nonlinear optical effects: nonlinear power transmission and spectral broadening of the LRSPP mode in the waveguides. Both nonlinear optical effects depend on the gold layer thickness. The theoretical model of these effects is based on the third-order susceptibility of the constituent materials. The linear and nonlinear parameters of the LRSPP mode are obtained, and the nonlinear Schrödinger equation is solved. The dispersion length is much larger than the waveguides length, and the chromatic dispersion does not affect the propagation of the plasmonic mode. We find that the third-order susceptibility of the gold layer has a dominant contribution to the effective third-order susceptibility of the LRSPP mode. The real part of the effective third-order susceptibility leads to the observed spectral broadening through the self-phase modulation effect, and its imaginary part determines the nonlinear absorption parameter and leads to the observed nonlinear power transmission. The experimental values of the third-order susceptibility of the gold layers are obtained. They indicate an effective enhancement of the third-order susceptibility for the gold layers, comparing to the bulk gold values. This enhancement is explained in terms of the change of the electrons motion.

  4. Effects of radioactive hot particles on pig skin

    Energy Technology Data Exchange (ETDEWEB)

    Kaurin, D.G.; Baum, J.W.; Schaefer, C.W. [and others

    1997-06-01

    The purpose of these studies was to determine the incidence and severity of lesions resulting from very localized deposition of dose to skin from small (< 0.5 mm) discrete radioactive particles as produced in the work environments of nuclear reactors. Hanford mini-pigs were exposed, both on a slightly off the skin, to localized replicate doses from 0.31 to 64 Gy (averaged over 1 cm{sup 2} at 70 {mu}m depth unless noted otherwise) using Sc-46, Yb-175, Tm-170, and fissioned UC{sub 2} isotopes having maximum beta-particle energies from about 0.3 to 3 MeV. Erythema and scabs (indicating ulceration) were scored for up to 71 days post-irradiation. The responses followed normal cumulative probability distributions, and therefore, no true threshold could be defined. Hence, 10 and 50% scab incidence rates were deduced using probit analyses. The lowest dose which produced 10% incidence was about 1 Gy for Yb-175 (0.5 MeV maximum energy) beta particle exposures, and about 3 to 9 Gy for other isotopes. The histopathology of lesions was determined at several doses. Single exposures to doses as large as 1,790 Gy were also given, and results were observed for up to 144 days post-exposure. Severity of detriment was estimated by analyzing the results in terms of lesion diameter, persistence, and infection. Over 1,100 sites were exposed. Only two exposed sites became infected after doses near 5000 Gy; the lesions healed quickly on treatment. 105 refs., 145 figs., 47 tabs.

  5. Nonlinear effects at the Fermilab Recycler e-cloud instability

    CERN Document Server

    Balbekov, V

    2016-01-01

    Theoretical analysis of e-cloud instability in the Fermilab Recycler is represented in the paper. The e-cloud in strong magnetic field is treated as a set of immovable snakes each being initiated by some proton bunch. It is shown that the instability arises because of injection errors of the bunches which increase in time and from the batch to its bunch being amplified by the e-cloud electric field. The particular attention is given to nonlinear additions to the cloud field. It is shown that the nonlinearity is the main factor which restricts growth of the bunch amplitude. Possible role of the field free parts of the Recycler id discussed as well. Results of calculations are compared with experimental data demonstrating good correlation.

  6. Collisional Effects on Nonlinear Ion Drag Force for Small Grains

    CERN Document Server

    Hutchinson, I H

    2013-01-01

    The ion drag force arising from plasma flow past an embedded spherical grain is calculated self-consistently and non-linearly using particle in cell codes, accounting for ion-neutral collisions. Using ion velocity distribution appropriate for ion drift driven by a force field gives wake potential and force greatly different from a shifted Maxwellian distribution, regardless of collisionality. The low-collisionality forces are shown to be consistent with estimates based upon cross-sections for scattering in a Yukawa (shielded) grain field, but only if non-linear shielding length is used. Finite collisionality initially enhances the drag force, but only by up to a factor of 2. Larger collisionality eventually reduces the drag force. In the collisional regime, the drift distribution gives larger drag than the shift distribution even at velocities where their collisionless drags are equal. Comprehensive practical analytic formulas for force that fit the calculations are provided.

  7. Chromatic and Dispersive Effects in Nonlinear Integrable Optics

    CERN Document Server

    Webb, Stephen D; Valishev, Alexander; Nagaitsev, Sergei N; Danilov, Viatcheslav V

    2015-01-01

    Proton accumulator rings and other circular hadron accelerators are susceptible to intensity-driven parametric instabilities because the zero-current charged particle dynamics are characterized by a single tune. Landau damping can suppress these instabilities, which requires energy spread in the beam or introducing nonlinear magnets such as octupoles. However, this approach reduces dynamic aperture. Nonlinear integrable optics can suppress parametric instabilities independent of energy spread in the distribution, while preserving the dynamic aperture. This novel approach promises to reduce particle losses and enable order-of-magnitude increases in beam intensity. In this paper we present results, obtained using the Lie operator formalism, on how chromaticity and dispersion affect particle orbits in integrable optics. We conclude that chromaticity in general breaks the integrability, unless the vertical and horizontal chromaticities are equal. Because of this, the chromaticity correcting magnets can be weaker ...

  8. Nonlinear Effects at the Fermilab Recycler e-Cloud Instability

    Energy Technology Data Exchange (ETDEWEB)

    Balbekov, V. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2016-06-10

    Theoretical analysis of e-cloud instability in the Fermilab Recycler is represented in the paper. The e-cloud in strong magnetic field is treated as a set of immovable snakes each being initiated by some proton bunch. It is shown that the instability arises because of injection errors of the bunches which increase in time and from bunch to bunch along the batch being amplified by the e-cloud electric field. The particular attention is given to nonlinear additions to the cloud field. It is shown that the nonlinearity is the main factor which restricts growth of the bunch amplitude. Possible role of the field free parts of the Recycler id discussed as well. Results of calculations are compared with experimental data demonstrating good correlation.

  9. Nonlinear effects of energetic particle driven instabilities in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Bruedgam, Michael

    2010-03-25

    In a tokamak plasma, a population of superthermal particles generated by heating methods can lead to a destabilization of various MHD modes. Due to nonlinear wave-particle interactions, a consequential fast particle redistribution reduces the plasma heating and can cause severe damages to the wall of the fusion device. In order to describe the wave-particle interaction, the drift-kinetic perturbative HAGIS code is applied which evolves the particle trajectories and the waves nonlinearly. For a simulation speed-up, the 6-d particle phase-space is reduced by the guiding centre approach to a 5-d description. The eigenfunction of the wave is assumed to be invariant, but its amplitude and phase is altered in time. A sophisticated {delta}/f-method is employed to model the change in the fast particle distribution so that numerical noise and the excessive number of simulated Monte-Carlo points are reduced significantly. The original code can only calculate the particle redistribution inside the plasma region. Therefore, a code extension has been developed during this thesis which enlarges the simulation region up to the vessel wall. By means of numerical simulations, this thesis addresses the problem of nonlinear waveparticle interactions in the presence of multiple MHD modes with significantly different eigenfrequencies and the corresponding fast particle transport inside the plasma. In this context, a new coupling mechanism between resonant particles and waves has been identified that leads to enhanced mode amplitudes and fast particle losses. The extension of the code provides for the first time the possibility of a quantitative and qualitative comparison between simulation results and recent measurements in the experiment. The findings of the comparison serve as a validation of both the theoretical model and the interpretation of the experimental results. Thus, a powerful interface tool has been developed for a deeper insight of nonlinear wave-particle interaction

  10. Nonlinear optical effects in pure and N-doped semiconductors

    CERN Document Server

    Donlagic, N S

    2000-01-01

    the optical response of a one-dimensional n-doped two-band semiconductor whose conduction band has been linearized with respect to the two Fermi points. Due to the linearization it is possible to calculate the linear and nonlinear response functions of the interacting electron system exactly. These response functions are then used in order to determine the linear absorption spectrum and the time-integrated signal of a degenerated four-wave-mixing experiment. It is shown that the well-known features of the linear response can directly be related to features of the nonlinear experiments. For example, the exponent which describes the algebraic decay of the time-integrated four-wave-mixing signal is functionally dependent on the exponent of the algebraic singularity in the linear absorption spectrum reflecting the common origin of the different phenomena. Over the last decades, the nonlinear optical properties of condensed matter systems have been an attractive and fruitful field of research. While the linear res...

  11. Nonlinear acoustic landmine detection: comparison of off-target soil background and on-target soil-mine nonlinear effects

    Science.gov (United States)

    Korman, Murray S.; Sabatier, James M.; Pauls, Kathleen E.; Genis, Sean A.

    2006-05-01

    When airborne sound at two primary tones, f I, f II (closely spaced near a resonance) excites the soil surface over a buried landmine, soil wave motion interacts with the landmine generating a scattered surface profile which can be measured over the "target." Profiles at the primaries f I, f II, and nonlinearly generated combination frequencies f I-(f II-f I) and f II+(f II-f I) , 2f I-(f II-f I), f I+f II and 2f II+(f II-f I) (among others) have been measured for a VS 2.2 plastic, inert, anti-tank landmine, buried at 3.6 cm in sifted loess soil and in a gravel road bed. [M.S. Korman and J.M. Sabatier, J. Acoust. Soc. Am. 116, 3354-3369 (2004)]. It is observed that the "on target" to "off target" contrast ratio for the sum frequency component can be ~20 dB higher than for either primary. The vibration interaction between the top-plate interface of a buried plastic landmine and the soil above it appears to exhibit many characteristics of the mesoscopic/nanoscale nonlinear effects that are observed in geomaterials like sandstone. Near resonance, the bending (softening) of a family of increasing amplitude tuning curves, involving the vibration over the landmine, exhibits a linear relationship between the peak particle velocity and corresponding frequency. Tuning curve experiments are performed both on and off the mine in an effort to understand the nonlinearities in each case.

  12. Electrically actuated MEMS resonators: Effects of fringing field and nonlinear viscoelasticity

    Science.gov (United States)

    Farokhi, Hamed; Ghayesh, Mergen H.

    2017-10-01

    This paper studies the nonlinear electromechanical response of a MEMS resonator numerically. A nonlinear continuous multi-physics model of the MEMS resonator is developed taking into account the effects of fringing field, size, residual axial load, and viscoelasticity. Moreover, both longitudinal and transverse motions are accounted for in the system modelling and simulations. The equations of motion of the MEMS resonator are obtained employing Hamilton's principle together with the modified version of the couple stress based theory (to account for size effects) and the Kelvin-Voigt model (to account for nonlinear energy dissipation). The Meijs-Fokkema electrostatic load formula is used to reliably model the fringing field effects. The continuous multi-physics model, consisting of geometrical, electrical, and viscos nonlinearities is discretised via a weighted-residual method, yielding a set of nonlinearly coupled ordinary differential equations (ODEs). The resultant set of ODEs is solved numerically when the microresonator is actuated by a biased DC voltage and an AC voltage. The results of the numerical simulations are presented in the form of DC voltage-deflection, DC voltage-natural frequency, and AC frequency-displacement diagrams. The effects of fringing field, residual axial load, small-scale, and nonlinear energy dissipation are highlighted. It is shown that fringing field effects are significant on both static and dynamic electromechanical responses of the MEMS resonator.

  13. Nonlinear flap-lag-extensional vibrations of rotating, pretwisted, preconed beams including Coriolis effects

    Science.gov (United States)

    Subrahmanyam, K. B.; Kaza, K. R. V.

    1985-01-01

    The effects of pretwist, precone, setting angle, Coriolis forces and second degree geometric nonlinearities on the natural frequencies, steady state deflections and mode shapes of rotating, torsionally rigid, cantilevered beams were studied. The governing coupled equations of flap lag extensional motion are derived including the effects of large precone and retaining geometric nonlinearities up to second degree. The Galerkin method, with nonrotating normal modes, is used for the solution of both steady state nonlinear equations and linear perturbation equations. Parametric indicating the individual and collective effects of pretwist, precone, Coriolis forces and second degree geometric nonlinearities on the steady state deflection, natural frequencies and mode shapes of rotating blades are presented. It is indicated that the second degree geometric nonlinear terms, which vanish for zero precone, can produce frequency changes of engineering significance. Further confirmation of the validity of including those generated by MSC NASTRAN. It is indicated that the linear and nonlinear Coriolis effects must be included in analyzing thick blades. The Coriolis effects are significant on the first flatwise and the first edgewise modes.

  14. A multilevel nonlinear mixed-effects approach to model growth in pigs

    DEFF Research Database (Denmark)

    Strathe, Anders Bjerring; Danfær, Allan Christian; Sørensen, H

    2009-01-01

    Growth functions have been used to predict market weight of pigs and maximize return over feed costs. This study was undertaken to compare 4 growth functions and methods of analyzing data, particularly one that considers nonlinear repeated measures. Data were collected from an experiment with 40...... pigs maintained from birth to maturity and their BW measured weekly or every 2 wk up to 1,007 d. Gompertz, logistic, Bridges, and Lopez functions were fitted to the data and compared using information criteria. For each function, a multilevel nonlinear mixed effects model was employed because....... Furthermore, studies should consider adding continuous autoregressive process when analyzing nonlinear mixed models with repeated measures....

  15. Nonlinear Absolute Nodal Coordinate Formulation of a Flexible Beam Considering Shear Effect

    Institute of Scientific and Technical Information of China (English)

    LIU Jin-yang; SHEN Ling-jie; HONG Jia-zhen

    2005-01-01

    Nonlinear modeling of a flexible beam with large deformation was investigated. Absolute nodal cooridnate formulation is employed to describe the motion, and Lagrange equations of motion of a flexible beam are derived based on the geometric nonlinear theory. Different from the previous nonlinear formulation with EulerBernoulli assumption, the shear strain and transverse normal strain are taken into account. Computational example of a flexible pendulum with a tip mass is given to show the effects of the shear strain and transverse normal strain. The constant total energy verifies the correctness of the present formulation.

  16. Nonlinear heat transport in mesoscopic conductors: Rectification, Peltier effect, and Wiedemann-Franz law

    Science.gov (United States)

    López, Rosa; Sánchez, David

    2013-07-01

    We investigate nonlinear heat properties in mesoscopic conductors using a scattering theory of transport. Our approach is based on a leading-order expansion in both the electrical and thermal driving forces. Beyond linear response, the transport coefficients are functions of the nonequilibrium screening potential that builds up in the system due to interactions. Within a mean-field approximation, we self-consistently calculate the heat rectification properties of a quantum dot attached to two terminals. We discuss nonlinear contributions to the Peltier effect and find departures from the Wiedemann-Franz law in the nonlinear regime of transport.

  17. SKIN PERMEATION ENHANCEMENT EFFECTS OF ASCORBIC ACID AND TRIETHYL CITRATE ON ROFECOXIB

    Directory of Open Access Journals (Sweden)

    MALAY K. DAS

    2008-01-01

    Full Text Available The enhancing effect of ascorbic acid and triethyl citrate (TEC on the in vitro skin permeation of rofecoxib across rat epidermis was investigated. Skin pre-treatment with ascorbic acid and TEC at different concentrations, followed by application of rofecoxib gel, showed higher permeation flux than the control condition. The mechanism underlying this permeation enhancement was probed with fourier transform infrared spectroscopy (FTIR. The FTIR spectra of rat epidermis treated with ascorbic acid revealed that ascorbic acid at low concentration appears to interact with dermal keratin, whereas at higher concentration it appears to interact with both dermal proteins and lipids. The FTIR spectra of rat epidermis treated with TEC showed a decrease in peak heights for both asymmetric and symmetric C-H stretching absorbance, indicating a change in the fluidity of alkyl chains in the intercellular lipids in the stratum corneum (SC. The protein disruption effect of TEC was probably due to the solvation of keratin by the formation of hydrogen bonds between TEC hydroxyl groups and keratin chain C=O groups. Skin pre-treatment with different concentrations of permeation enhancers did not show any significant change in lag time in comparison to control. The amount of rofecoxib retained in the skin after skin pre-treatment with enhancers was found to be higher than in the experiment without skin pre-treatment. Scanning electron microscopy (SEM confirmed the maintenance of skin integrity throughout the permeation experiment. The observed permeation enhancing effects of ascorbic acid and TEC in the present study indicate that a rapid percutaneous absorption of rofecoxib at effective therapeutic levels may facilitate faster anti-inflammatory activity.

  18. Non-linear elasticity of core/shell spun PGS/PLLA fibres and their effect on cell proliferation.

    Science.gov (United States)

    Xu, Bing; Rollo, Ben; Stamp, Lincon A; Zhang, Dongcheng; Fang, Xiya; Newgreen, Donald F; Chen, Qizhi

    2013-09-01

    An efficient delivery system is critical for the success of cell therapy. To deliver cells to a dynamic organ, the biomaterial vehicle should mechanically match with the non-linearly elastic host tissue. In this study, non-linearly elastic biomaterials have been fabricated from a chemically crosslinked elastomeric poly(glycerol sebacate) (PGS) and thermoplastic poly(l-lactic acid) (PLLA) using the core/shell electrospinning technique. The spun fibrous materials containing a PGS core and PLLA shell demonstrate J-shaped stress-strain curves, having ultimate tensile strength (UTS), rupture elongation and stiffness constants of 1 ± 0.2 MPa, 25 ± 3% and 12 ± 2, respectively, which are comparable to skin tissue properties reported previously. Our ex vivo and in vivo trials have shown that the elastomeric mesh supports and fosters the growth of enteric neural crest (ENC) progenitor cells, and that the cell-seeded elastomeric fibrous sheet physically remains in intimate contact with guts after grafting, providing the effective delivery of the progenitor cells to an embryonic and post-natal gut environment.

  19. Skin health promotion effects of natural beta-glucan derived from cereals and microorganisms: a review.

    Science.gov (United States)

    Du, Bin; Bian, Zhaoxiang; Xu, Baojun

    2014-02-01

    β-Glucans are natural cell wall polysaccharides found in yeast, fungi (including mushrooms), some bacteria, seaweeds and cereals. Natural β-glucans possess many health promotion effects on human health, such as anti-tumor, anti-diabetes, anti-infection, lowering blood cholesterol and immune-modulating properties. These effects have been reviewed previously. However, skin health promotion of β-glucan derived from cereals and microorganisms has received little attention. This review focuses on antioxidant activity, anti-wrinkle activity, anti-ultraviolet light, wound healing, and moisturizing effect and skin permeation absorption of β-glucan. Furthermore, applications of β-glucan in cosmetics are also discussed.

  20. Ductile and Compacted Graphite Iron Casting Skin -- Evaluation, Effect on Fatigue Strength and Elimination

    Science.gov (United States)

    Boonmee, Sarum

    Compacted graphite (CG) iron features a good combination of tensile strength, impact resistance, thermal conductivity and damping capacity. This combination makes CG iron a material of choice for various applications, especially for the automobile industry. The mechanical properties of CG iron listed in the standards (i.e. ASTM) are for machined specimens. However, since most iron castings retain the original casting surface (a.k.a. casting skin), the actual performance of the part could be significantly different from that of the machined specimens. Recent studies have shown the negative effect of the casting skin, but little quantification of its effect on mechanical properties is available. Further, the understanding of its mechanism of formation is at best incomplete. In this research, the effect of the casting skin on mechanical properties in CG and ductile irons (DI) is explored. The differences in tensile and fatigue properties between as-cast and machined samples were quantified and correlated to the casting skin features. It was found that the presence of the casting skin was accountable for 9% reduction of tensile strength and up to 32% reduction of fatigue strength (for CG iron with 40% nodularity). Several mechanisms of the casting skin formation are proposed in this research. The formation of ferritic and pearlitic rims is explained by decarburizing/carburizing reactions at the mold/metal interface. Mg depletion and solidification kinetics effect were identified as the formation mechanisms of the graphite degradation. A 2-D thermal diffusion model was formulated based on Mg depletion theory. The model can be used to predict the casting skin thickness when Mg depletion is the dominant mechanism. Furthermore, using the asymmetric Fe-Gr phase diagram, some instances of casting skin formation were explained based on solidification kinetics theory. The experimental microstructural evidence and the theoretical progress were conducive to the development of

  1. Noise-induced transitions and resonant effects in nonlinear systems

    Science.gov (United States)

    Zaikin, Alexei

    2003-02-01

    Our every-day experience is connected with different acoustical noise or music. Usually noise plays the role of nuisance in any communication and destroys any order in a system. Similar optical effects are known: strong snowing or raining decreases quality of a vision. In contrast to these situations noisy stimuli can also play a positive constructive role, e.g. a driver can be more concentrated in a presence of quiet music. Transmission processes in neural systems are of especial interest from this point of view: excitation or information will be transmitted only in the case if a signal overcomes a threshold. Dr. Alexei Zaikin from the Potsdam University studies noise-induced phenomena in nonlinear systems from a theoretical point of view. Especially he is interested in the processes, in which noise influences the behaviour of a system twice: if the intensity of noise is over a threshold, it induces some regular structure that will be synchronized with the behaviour of neighbour elements. To obtain such a system with a threshold one needs one more noise source. Dr. Zaikin has analyzed further examples of such doubly stochastic effects and developed a concept of these new phenomena. These theoretical findings are important, because such processes can play a crucial role in neurophysics, technical communication devices and living sciences. Unsere alltägliche Erfahrung ist mit verschiedenen akustischen Einfluessen wie Lärm, aber auch Musik verbunden. Jeder weiss, wie Lärm stören kann und Kommunikation behindert oder gar unterbindet. Ähnliche optische Effekte sind bekannt: starkes Schneetreiben oder Regengüsse verschlechtern die Sicht und lassen uns Umrisse nur noch schemenhaft erkennen. Jedoch koennen ähnliche Stimuli auch sehr positive Auswirkungen haben: Autofahrer fahren bei leiser Musik konzentrierter -- die Behauptung von Schulkindern, nur bei dröhnenden Bässen die Mathehausaufgaben richtig rechnen zu können, ist allerdings nicht wissenschaftlich

  2. Unexpected Nonlinear Effects in Superconducting Transition-Edge Sensors

    Science.gov (United States)

    Sadleir, John

    2016-01-01

    When a normal metal transitions into the superconducting state the DC resistance drops from a finite value to zero over some finite transition width in temperature, current, and magnetic field. Superconducting transition-edge sensors (TESs) operate within this transition region and uses resistive changes to measure deposited thermal energy. This resistive transition is not perfectly smooth and a wide range of TES designs and materials show sub-structure in the resistive transition (as seen in smooth nonmonotonic behavior, jump discontinuities, and hysteresis in the devices current-voltage relation and derivatives of the resistance with respect to temperature, bias current, and magnetic field). TES technology has advanced to the point where for many applications this structure is the limiting factor in performance and optimization consists of finding operating points away from these structures. For example, operating at or near this structure can lead to nonlinearity in the detectors response and gain scale, limit the spectral range of the detector by limiting the usable resistive range, and degrade energy resolution. The origin of much of this substructure is unknown. This presentation investigates a number of possible sources in turn. First we model the TES as a superconducting weak-link and solve for the characteristic differential equations current and voltage time dependence. We find:(1) measured DC biased current-voltage relationship is the time-average of a much higher frequency limit cycle solution.(2) We calculate the fundamental frequency and estimate the power radiated from the TES treating the bias leads as an antennae.(3) The solution for a set of circuit parameters becomes multivalued leading to current transitions between levels.(4)The circuit parameters can change the measure resistance and mask the true critical current. As a consequence the TES resistance surface is not just a function of temperature, current, and magnetic field but is also a

  3. Effect of Colorspace Transformation, the Illuminance Component, and Color Modeling on Skin Detection

    Energy Technology Data Exchange (ETDEWEB)

    Jayaram, S; Schmugge, S; Shin, M C; Tsap, L V

    2004-03-22

    Skin detection is an important preliminary process in human motion analysis. It is commonly performed in three steps: transforming the pixel color to a non-RGB colorspace, dropping the illumination component of skin color, and classifying by modeling the skin color distribution. In this paper, we evaluate the effect of these three steps on the skin detection performance. The importance of this study is a new comprehensive colorspace and color modeling testing methodology that would allow for making the best choices for skin detection. Combinations of nine colorspaces, the presence of the absence of the illuminance component, and the two color modeling approaches are compared. The performance is measured by using a receiver operating characteristic (ROC) curve on a large dataset of 805 images with manual ground truth. The results reveal that (1) the absence of the illuminance component decreases performance, (2) skin color modeling has a greater impact than colorspace transformation, and (3) colorspace transformations can improve performance in certain instances. We found that the best performance was obtained by transforming the pixel color to the SCT, HSI, or CIELAB colorspaces, keeping the illuminance component, and modeling the color with the histogram approach.

  4. Effect of Acupuncture Manipulations at LI4 or LI11 on Blood Flow and Skin Temperature.

    Science.gov (United States)

    Li, Weihui; Ahn, Andrew

    2016-06-01

    Acupuncture induces physiological changes, and patients have reported warm or cool sensations with "Burning Fire" (BF) or "Penetrating Cool" (PC) manipulations. This study aimed to evaluate whether these techniques had distinct effects on skin temperature and blood flow and to examine whether skin temperature correlated with blood flow. The participants were 25 healthy volunteers, each receiving acupuncture manipulations on points LI4 and LI11 bilaterally. Skin temperatures and blood flow were recorded continuously on both arms. The study found that acupuncture significantly increased skin temperature on the needling arm by 0.3514°C on average, but decreased it on the contralateral arm by 0.2201°C on average. Blood flow decreased significantly in both arms during needling (-3.4% and -5.97% for the ipsilateral and the contralateral sides, respectively), but the changes in skin temperature did not correlate with the changes in blood flow. Furthermore, these changes were not significantly different between acupuncture techniques and acupuncture points. In conclusion, acupuncture changes local skin temperature and blood flow independent of the manipulation technique. Moreover, blood flow may not be affected by the increased temperature on the needling arm. These results help to verify traditional Chinese medicine concepts and may help in establishing standards for acupuncture treatments.

  5. Morphogenetic effect of rotated skin cuffs on tail regeneration in Plethodon cinereus.

    Science.gov (United States)

    Dinsmore, C E

    1981-02-01

    As an epimorphic system, the urodele tail has much in common with the urodele limb, relative to tissue components. In an effort to elucidate potentially similar functions of the skin during regeneration, two procedures which have been shown to be highly disruptive of limb morphogenesis were performed on the tail. In the first, cuffs of tail skin were rotated 180 degrees about the long axis of tails in Plethodon cinereus. Subsequent amputation through the rotated cuffs produced regenerates at a normal rate which were also normal in both internal architecture and skin gland distribution. In a second series, cuffs of tail skin were rotated 90 degrees about the dorso-ventral axis of the tail, such that the dorsal red stripe encircled the tail. Upon amputation through the middle of the cuff, the stump skin presented an exclusively dorsal surface which, nevertheless, had no effect upon the morphogenetic success of the regenerate. These data therefore indicate that a tissue, such as skin, may be inconsistent in its morphogenetic influence among epimorphic fields within the same organism. It is not clear whether these results reflect differences in field behavior or in absolute tissue potential determined by the field of origin. A tissue hierarchy of morphogenetic influence within and among epimorphic fields is suggested as a preliminary framework within which to coordinate such information.

  6. Evaluation of the effectiveness of wet ice, dry ice, and cryogenic packs in reducing skin temperature.

    Science.gov (United States)

    Belitsky, R B; Odam, S J; Hubley-Kozey, C

    1987-07-01

    The purposes of this study were to evaluate and compare the ability of wet ice (WI), dry ice (DI), and cryogenic packs (CGPs) to reduce and maintain the reduction of skin temperature directly under the cooling agent and to determine whether the cooling effect on skin extended beyond the surface area in contact with the cooling agent. Ten female volunteers participated in the study, and each of the three cold modalities was applied randomly to the skin overlying the right triceps surae muscle. After 15 minutes of cold application, mean skin temperatures recorded under WI, DI, and CGP decreased 12 degrees, 9.9 degrees, and 7.3 degrees C, respectively. The only significant differences in cooling were between WI and DI and between WI and CGP. Fifteen minutes after removal of the cold modalities, no significant differences were found in mean skin temperature between WI, DI, and CGP. The residual mean decrease in skin temperature between the pretreatment rest interval (time 0) and 15 minutes after removal of the cold modality (time 30) was significant for WI only. No cooling was demonstrated 1 cm proximal or distal to any of the cooling agents after 15 minutes of cold application. These findings provide valuable information for the use of cryotherapy in the clinical setting.

  7. Effect of surface topographic features on the optical properties of skin: a phantom study

    Science.gov (United States)

    Liu, Guangli; Chen, Jianfeng; Zhao, Zuhua; Zhao, Gang; Dong, Erbao; Chu, Jiaru; Xu, Ronald X.

    2016-10-01

    Tissue-simulating phantoms are used to validate and calibrate optical imaging systems and to understand light transport in biological tissue. Light propagation in a strongly turbid medium such as skin tissue experiences multiple scattering and diffuse reflection from the surface. Surface roughness introduces phase shifts and optical path length differences for light which is scattered within the skin tissue and reflected from the surface. In this paper, we study the effect of mismatched surface roughness on optical measurement and subsequent determination of optical properties of skin tissue. A series of phantoms with controlled surface features and optical properties corresponding to normal human skin are fabricated. The fabrication of polydimethylsiloxane (PDMS) phantoms with known surface roughness follows a standard soft lithography process. Surface roughness of skin-simulating phantoms are measured with Bruker stylus profiler. The diffuse reflectance of the phantom is validated by a UV/VIS spectrophotometer. The results show that surface texture and roughness have considerable influence on the optical characteristics of skin. This study suggests that surface roughness should be considered as an important contributing factor for the determination of tissue optical properties.

  8. Ultraviolet-radiation and skin cancer. Effect of an ozone layer depletion.

    Science.gov (United States)

    Henriksen, T; Dahlback, A; Larsen, S H; Moan, J

    1990-05-01

    The effect of changes in the ozone layer on the incidence of skin cancer was explored using data for Norway. Attempts were made to arrive at a relationship between the "environmental effective UV-dose" and the skin cancer incidence. Norway is well suited for this purpose because of the large variation in the annual UV-dose from north to south. Furthermore we have a well developed cancer registry and a homogeneous population with regard to skin type. Four different regions of the country, each with a broadness of 1 degree in latitude (approximately 111 km), were selected (located around 69.5, 63.5, 60 and 58.5 degrees N). The annual effective UV-doses for these regions were calculated, assuming normal ozone conditions throughout the year and the action spectrum proposed by CIE, which extends up to 400 nm. The incidence rate (in the period 1970-1980) of malignant melanoma and non-melanoma skin cancer (mainly basal cell carcinoma) increased with the annual environmental UV-doses. For both these types of cancer a quadratic dose-effect relationship seems to be valid to a first approximation. The present data indicate that the incidence of skin cancer would increase by approximately 2% for each percent ozone reduction.

  9. Cytotoxic effects of five commonly abused skin toning (bleaching) creams on Allium cepa root tip mitosis.

    Science.gov (United States)

    Udengwu, O S; Chukwujekwu, J C

    2008-09-15

    The Allium test was used to study the cytotoxic effects of five commonly abused skin toning creams--Ikb, Tura, Top gel, Dorot and Mililo. These creams are commonly used by some black skinned people (especially the females) as skin lightening (bleaching) agents. The results showed that all the five bleaching creams were mito-depressive in action. They exhibited both chromatoclassic and mitoclassic effects. Their depressive effects were found to increase with duration of treatment. The induced abnormalities included chromosome contraction, spindle breakages, c-metaphase, star anaphase, chromosome stickiness and sticky bridges, precocious chromosome movement as well as endomitosis. It is suggested that since all eukaryotic cells are basically the same, these observed abnormalities could be similar to the effects these chemicals have on human skin when they are applied. Some of these are known to cause alteration in melanin formation as well as the biosynthesis of the enzyme tyrosinase. Furthermore, since certain points on the chromosomes called fragile sites have been implicated in oncogenesis, the observed abnormalities may be part of (or include) the switching on mechanisms of such genes, which could be responsible for the transformation of normal skin cells to malignant cells in those who abuse these creams.

  10. Addition of antifungal skin bacteria to salamanders ameliorates the effects of chytridiomycosis.

    Science.gov (United States)

    Harris, Reid N; Lauer, Antje; Simon, Mary Alice; Banning, Jenifer L; Alford, Ross A

    2009-01-28

    Chytridiomycosis, caused by the skin fungus Batrachochytrium dendrobatidis (Bd), has caused population declines of many amphibians in remote protected habitats. Progress has been made in understanding the pathogen's life cycle, documenting its devastating effects on individual amphibians and on populations, and understanding how and why disease outbreaks occur. No research has directly addressed the critical question of how to prevent declines and extinctions caused by outbreaks of the disease. We have identified a number of bacterial species of amphibian skin that inhibit Bd in vitro. Here, we demonstrate that a species of anti-Bd skin bacteria can be successfully added to skins of salamanders Plethodon cinereus, and that addition of this bacterium reduced the severity of a disease symptom in experimentally infected individuals. This is the first demonstration that manipulating the natural skin microbiota of an amphibian species can alter the pathogen's negative effects on infected amphibians and appears to be the first demonstration that an epibiotic manipulation of any wildlife species can lessen the effects of an emerging infectious disease. It suggests that probiotic or bio-augmentation manipulations of cutaneous microbiota could have the potential to reduce susceptibility of amphibians to the disease in nature. This is the first approach suggested that could slow or halt epidemic outbreaks and allow successful reintroductions of amphibian species that have become locally or globally extinct in the wild. Our results also suggest a mechanism for the association of climate change and the likelihood of chytridiomycosis outbreaks via the effects of the former on antifungal bacterial communities.

  11. Engineering chromatic dispersion and effective nonlinearity in a dual-slot waveguide.

    Science.gov (United States)

    Liu, Yan; Yan, Jing; Han, Genquan

    2014-09-20

    In this paper, we propose a new dual slot based on rib-like structure, which exhibits a flat and near-zero dispersion over a 198 nm wide wavelength range. Chromatic dispersion of dual-slot silicon (Si) waveguide is mainly determined by waveguide dispersion due to the manipulating mode effective area rather than by the material dispersion. Moreover, the nonlinear coefficient and effective mode area of the waveguide are also explored in detail. A nonlinear coefficient of 1460/m/W at 1550 nm is achieved, which is 10 times larger than that of the Si rib waveguide. By changing different waveguide variables, both the dispersion and nonlinear coefficient can be tailored, thus enabling the potential for a highly nonlinear waveguide with uniform dispersion over a wide wavelength range, which could benefit the performance of broadband optical signal systems.

  12. Modal theory of slow light enhanced third-order nonlinear effects in photonic crystal waveguides.

    Science.gov (United States)

    Chen, Tao; Sun, Junqiang; Li, Linsen

    2012-08-27

    In this paper, we derive the couple-mode equations for third-order nonlinear effects in photonic crystal waveguides by employing the modal theory. These nonlinear interactions include self-phase modulation, cross-phase modulation and degenerate four-wave mixing. The equations similar to that in nonlinear fiber optics could be expanded and applied for third-order nonlinear processes in other periodic waveguides. Based on the equations, we systematically analyze the group-velocity dispersion, optical propagation loss, effective interaction area, slow light enhanced factor and phase mismatch for a slow light engineered silicon photonic crystal waveguide. Considering the two-photon and free-carrier absorptions, the wavelength conversion efficiencies in two low-dispersion regions are numerically simulated by utilizing finite difference method. Finally, we investigate the influence of slow light enhanced multiple four-wave-mixing process on the conversion efficiency.

  13. On the effects of nonlinearities in room impulse response measurements with exponential sweeps

    DEFF Research Database (Denmark)

    Ciric, Dejan; Markovic, Milos; Mijic, Miomir

    2013-01-01

    In room impulse response measurements, there are some common disturbances that affect the measured results. These disturbances include nonlinearity, noise and time variance. In this paper, the effects of nonlinearities in the measurements with exponential sweep-sine signals are analyzed from...... different perspectives. The analysis combines theoretical approach, simulations and measurements. The focus is on distortion artifacts in the causal part of the impulse response and their effects on room acoustical parameters. The results show that the sweep-sine method is vulnerable to a certain extent...... to nonlinearities from a theoretical standpoint, but the consequences of this vulnerability are reduced in the responses measured in practice. However, due to irretrievable contamination of the impulse responses, the nonlinearities (especially strong ones) should be avoided....

  14. Effect of alpha lipoic acid on smoking-induced skin damage.

    Science.gov (United States)

    Yıldırım Baş, Funda; Bayram, Dilek; Arslan, Bahriye; Armağan, Ilkay; Yeşilot, Şükriye; Çiçek, Emine; Yorgancıgil, Emre

    2017-03-01

    Exposed to cigarette leads to the formation of reactive oxygen species and the generation of bioactive molecules that can damage skin cells. This investigation was carried out to study possible effects of Alpha Lipoic Acid (ALA) on smoking-induced rat skin injury. 28 Spraque-Dawley female rats were allocated into three groups: control group (n = 8), smoking group (n = 10; 12 cigarettes/day, 8 weeks) and smoking + ALA group (n = 10; 12 cigarettes/day + 100 mg/kg, 8 weeks). Experiment group animals were sacrificed under anaesthesia with 10%ketamine + 2%xylasine at the end of second mounts and then skin examples were taken from the epigastric area. Histochemical (Haematoxylin-Eosin and Masson's trichrome, immunohistochemical (TNF-α) and biochemical analysis (CAT, MDA and protein carbonylation) were performed on these skin tissues. Histologically, skin was distinguished normal structure in the control group. In the smoking group, collagen bundles and hair follicle degradation/reduction, sweat gland degeneration, mononuclear cell infiltration in dermis were encountered. In ALA-treated group, all of these changes were improved (p  0.05). MDA; which is indicator of lipid peroxidation was significantly higher in cigarette group than in control group (p  0.05). In the ALA it was significantly lower compared to the control group and cigarette (p skin tissues in rats. However, ALA has a curative effect on cigarette-induced injuries on the skin tissues by anti-oxidative and anti-inflammatory effects.

  15. Nonlinear Bubble Dynamics And The Effects On Propagation Through Near-Surface Bubble Layers

    Science.gov (United States)

    Leighton, Timothy G.

    2004-11-01

    Nonlinear bubble dynamics are often viewed as the unfortunate consequence of having to use high acoustic pressure amplitudes when the void fraction in the near-surface oceanic bubble layer is great enough to cause severe attenuation (e.g. >50 dB/m). This is seen as unfortunate since existing models for acoustic propagation in bubbly liquids are based on linear bubble dynamics. However, the development of nonlinear models does more than just allow quantification of the errors associated with the use of linear models. It also offers the possibility of propagation modeling and acoustic inversions which appropriately incorporate the bubble nonlinearity. Furthermore, it allows exploration and quantification of possible nonlinear effects which may be exploited. As a result, high acoustic pressure amplitudes may be desirable even in low void fractions, because they offer opportunities to gain information about the bubble cloud from the nonlinearities, and options to exploit the nonlinearities to enhance communication and sonar in bubbly waters. This paper presents a method for calculating the nonlinear acoustic cross-sections, scatter, attenuations and sound speeds from bubble clouds which may be inhomogeneous. The method allows prediction of the time dependency of these quantities, both because the cloud may vary and because the incident acoustic pulse may have finite and arbitrary time history. The method can be readily adapted for bubbles in other environments (e.g. clouds of interacting bubbles, sediments, structures, in vivo, reverberant conditions etc.). The possible exploitation of bubble acoustics by marine mammals, and for sonar enhancement, is explored.

  16. Effect of diaper cream and wet wipes on skin barrier properties in infants: a prospective randomized controlled trial.

    Science.gov (United States)

    Garcia Bartels, Natalie; Lünnemann, Lena; Stroux, Andrea; Kottner, Jan; Serrano, José; Blume-Peytavi, Ulrike

    2014-01-01

    The effect of different diaper care procedures on skin barrier function in infants has been minimally investigated and may be assessed using objective methods. In a single-center, prospective trial, 89 healthy 9-month-old infants (±8 wks) were randomly assigned to three diaper care regimens: group I used water-moistened washcloths at diaper changes (n = 30), group II additionally applied diaper cream twice daily (n = 28), and group III used wet wipes and diaper cream twice daily (n = 31). Transepidermal water loss (TEWL), skin hydration (SCH), skin pH, interleukin 1α (IL-1α) levels, and microbiologic colonization were measured in diapered skin (upper outer quadrant of the buttocks), nondiapered skin (upper leg), and if diaper dermatitis (DD) occurred, using the most affected skin area at day 1 and weeks 4 and 8. Skin condition was assessed utilizing a neonatal skin condition score and diaper rash grade. On diapered skin, SCH decreased in groups II and III, whereas TEWL values were reduced in group II only. Skin pH increased in groups II and III. In general, SCH, skin pH, and IL-1α levels were higher in healthy diapered skin than in nondiapered skin. The incidence and course of DD was comparable in all groups. Areas with DD had greater TEWL and skin pH than unaffected skin areas. Infants who received diaper cream had lower SCH and TEWL and higher pH levels in the diapered area than on nondiapered skin. No correlation with the occurrence of DD was found. © 2014 Wiley Periodicals, Inc.

  17. Effects of Cosmetic Formulations Containing Hydroxyacids on Sun-Exposed Skin: Current Applications and Future Developments

    Directory of Open Access Journals (Sweden)

    Andrija Kornhauser

    2012-01-01

    Full Text Available This paper describes recent data on the effects of various skin formulations containing hydroxyacids (HAs and related products on sun-exposed skin. The most frequently used classes of these products, such as α- and β-hydroxyacids, polyhydroxy acids, and bionic acids, are reviewed, and their application in cosmetic formulations is described. Special emphasis is devoted to the safety evaluation of these formulations, particularly on the effects of their prolonged use on sun-exposed skin. We also discuss the important contribution of cosmetic vehicles in these types of studies. Data on the effects of HAs on melanogenesis and tanning are also included. Up-to-date methods and techniques used in those explorations, as well as selected future developments in the cosmetic area, are presented.

  18. Skin effect mitigation in laser processed multi-walled carbon nanotube/copper conductors

    Energy Technology Data Exchange (ETDEWEB)

    Keramatnejad, K.; Zhou, Y. S.; Gao, Y.; Rabiee Golgir, H.; Wang, M.; Lu, Y. F., E-mail: ylu2@unl.edu [Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511 (United States); Jiang, L. [School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 (China); Silvain, J.-F. [Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB-CNRS) 87, Avenue du Docteur Albert Schweitzer F-33608 Pessac Cedex (France)

    2015-10-21

    In this study, laser-processed multi-walled carbon nanotube (MWCNT)/Cu conductors are introduced as potential passive components to mitigate the skin effect of Cu at high frequencies (0–10 MHz). Suppressed skin effect is observed in the MWCNT/Cu conductors compared to primitive Cu. At an AC frequency of 10 MHz, a maximum AC resistance reduction of 94% was observed in a MWCNT/Cu conductor after being irradiated at a laser power density of 189 W/cm{sup 2}. The reduced skin effect in the MWCNT/Cu conductors is ascribed to the presence of MWCNT channels which are insensitive to AC frequencies. The laser irradiation process is observed to play a crucial role in reducing contact resistance at the MWCNT-Cu interfaces, removing impurities in MWCNTs, and densifying MWCNT films.

  19. The vasorelaxant effect of adrenomedullin, proadrenomedullin N-terminal 20 peptide and amylin in human skin

    DEFF Research Database (Denmark)

    Hasbak, Philip; Eskesen, Karen; Lind, Peter Henrik

    2006-01-01

    In this study we aimed to assess in vivo, the vasodilator effects of adrenomedullin, proadrenomedullin N-terminal 20 peptide (PAMP) and amylin in human skin vasculature and compare the responses to the effects mediated by the endogenous neuropeptides calcitonin gene-related peptide (CGRP......) and substance P and to examine the mRNA expression of calcitonin receptor-like receptor (CL-R) and receptor-activity modifying proteins, RAMP1, RAMP 2 and RAMP3 in human subcutaneous arteries. Changes in skin blood flow of the forearm were measured using a Laser Doppler Imager after intradermal injection...... of CGRP, adrenomedullin and amylin induces long lasting dilatation of human skin vasculature by activation of CGRP1 receptors. PAMP induces transient vasodilatation. PAMP but not CGRP, adrenomedullin and amylin causes itch sensation and local erythema. The transient effect on vasodilatation as response...

  20. Analysis of nonlinearities and effects in direct drive electro-hydraulic position servo system

    Institute of Scientific and Technical Information of China (English)

    WANG Hong-jie; JI Tian-jing; MAO Xin-tao; LIU Quan-zhong

    2005-01-01

    The direct drive electro-hydraulic servo system is a new approach hydraulic system. It is much smaller and easier controlled than traditional systems and is a perfect energy saver. This paper will briefly introduce the popular nonlinearities in the electro-hydraulic system and analyse the effect of nonlinearities in direct drive electro-hydraulic position servo system by means of simulation research. Some valuable conclusions are given.

  1. Skin-whitening and skin-condition-improving effects of topical oxidized glutathione: a double-blind and placebo-controlled clinical trial in healthy women

    Directory of Open Access Journals (Sweden)

    Watanabe F

    2014-10-01

    Full Text Available Fumiko Watanabe,1 Erika Hashizume,1 Gertrude P Chan,2 Ayako Kamimura11Healthcare Products Development Center, KYOWA HAKKO BIO CO., LTD., Tsukuba, Ibaraki, Japan; 2Clinical Trial Management and Testing Associates, Inc., Filinvest Corporate City, Alabang, Muntinlupa City, PhilippinesPurpose: Glutathione is a tripeptide consisting of cysteine, glycine, and glutamate and functions as a major antioxidant. It is synthesized endogenously in humans. Glutathione protects thiol protein groups from oxidation and is involved in cellular detoxification for maintenance of the cell environment. Reduced glutathione (GSH has a skin-whitening effect in humans through its tyrosinase inhibitory activity, but in the case of oxidized glutathione (GSSG this effect is unclear. We examined the skin-whitening and skin-condition effects of topical GSSG in healthy women.Subjects and methods: The subjects were 30 healthy adult women aged 30 to 50 years. The study design was a randomized, double-blind, matched-pair, placebo-controlled clinical trial. Subjects applied GSSG 2% (weight/weight [w/w] lotion to one side of the face and a placebo lotion to the other side twice daily for 10 weeks. We objectively measured changes in melanin index values, moisture content of the stratum corneum, smoothness, wrinkle formation, and elasticity of the skin. The principal investigator and each subject also used subjective scores to investigate skin whitening, wrinkle reduction, and smoothness. Analysis of variance was used to evaluate differences between groups.Results: The skin melanin index was significantly lower with GSSG treatment than with placebo from the early weeks after the start of the trial through to the end of the study period (at 10 weeks, P<0.001. In addition, in the latter half of the study period GSSG-treated sites had significant increases in moisture content of the stratum corneum, suppression of wrinkle formation, and improvement in skin smoothness. There were no

  2. Strong electronic correlation effects in coherent multidimensional nonlinear optical spectroscopy.

    Science.gov (United States)

    Karadimitriou, M E; Kavousanaki, E G; Dani, K M; Fromer, N A; Perakis, I E

    2011-05-12

    We discuss a many-body theory of the coherent ultrafast nonlinear optical response of systems with a strongly correlated electronic ground state that responds unadiabatically to photoexcitation. We introduce a truncation of quantum kinetic density matrix equations of motion that does not rely on an expansion in terms of the interactions and thus applies to strongly correlated systems. For this we expand in terms of the optical field, separate out contributions to the time-evolved many-body state due to correlated and uncorrelated multiple optical transitions, and use "Hubbard operator" density matrices to describe the exact dynamics of the individual contributions within a subspace of strongly coupled states, including "pure dephasing". Our purpose is to develop a quantum mechanical tool capable of exploring how, by coherently photoexciting selected modes, one can trigger nonlinear dynamics of strongly coupled degrees of freedom. Such dynamics could lead to photoinduced phase transitions. We apply our theory to the nonlinear response of a two-dimensional electron gas (2DEG) in a magnetic field. We coherently photoexcite the two lowest Landau level (LL) excitations using three time-delayed optical pulses. We identify some striking temporal and spectral features due to dynamical coupling of the two LLs facilitated by inter-Landau-level magnetoplasmon and magnetoroton excitations and compare to three-pulse four-wave-mixing (FWM) experiments. We show that these features depend sensitively on the dynamics of four-particle correlations between an electron-hole pair and a magnetoplasmon/magnetoroton, reminiscent of exciton-exciton correlations in undoped semiconductors. Our results shed light into unexplored coherent dynamics and relaxation of the quantum Hall system (QHS) and can provide new insight into non-equilibrium co-operative phenomena in strongly correlated systems.

  3. The effect of the iBEAM Evo carbon fiber tabletop on skin sparing.

    Science.gov (United States)

    Simpson, John B; Godwin, Guy A

    2011-01-01

    Replicating the attenuation properties of the treatment tabletop are of primary importance for accurate treatment planning; however, the effect of the tabletop on the skin-sparing properties of x-rays can be overlooked. Under some conditions, the reaction of skin to the radiation can be so serious as to be the dose-limiting organ for radiotherapy treatment. Hence, an understanding of the magnitude of the reduction in skin sparing is important. Because of the development of image-guided radiotherapy, modern tabletops have been developed without the use of metal supports that otherwise provided the necessary level of rigidity. Rigidity is instead provided by compressed foam within a carbon-fiber shell, which, although it provides artefact-free imaging and high levels of rigidity, has an adverse affect on the dose in the build-up region. Representative of this type is the iBEAM evo tabletop, whose effect on the skin dose was determined at 6-MV, 10-MV, and 18-MV x-rays. Skin dose was found to increase by 60-70% owing to the tabletop, with the effect increasing with field size and decreasing with energy. By considering an endpoint of erythema, a radiobiological advantage of selecting 10 MV over 6 MV for applicable treatments was demonstrated.

  4. SONOPHORESIS EFFECT ON THE PERMEATION OF METRONIDAZOLE USING 3D SKIN EQUIVALENT

    Directory of Open Access Journals (Sweden)

    Mai Aldwaikat*, Mohammed Alarjah , Jacki Willis and Timothy Mason

    2013-01-01

    Full Text Available Transdermal drug delivery is highly advantageous method for drug administration, yet the compact structure of stratum corneum is an effective barrier which limited the use of this route to very few drug molecules. Ultrasound enhances the permeation through the skin by altering this barrier function in a phenomenon named sonophoresis. This study aimed to evaluate the effect of variable ultrasonic conditions on the permeation of Metronidazole (ML. This involved validating the applicability of utilizing a three dimensional skin equivalent as human skin models for sonophoresis studies. A Franz diffusion cell was used to study the effect of therapeutic ultrasound at 1 MHz and power ultrasound at 20 KHz on the permeation of Metronidazole across the 3D skin equivalent EpiDerm™. HPLC methods were used for the determination of the concentration of Metronidazole in the receiving compartment. Utilizing therapeutic ultrasound at 1 MHz frequency has enhanced the permeation of Metronidazole through the EpiDerm™, as about double the permeation of the ML was obtained with no apparent damage to the membrane. The results indicated significant permeation enhancement with low frequency sonophoresis at 20 KHz frequency treatments through EpiDerm™ skin equivalent. Up to five fold enhancement was measured with the permeation of investigated molecules through EpiDerm™. The mechanism of action observed seemed highly dependent on the ultrasonic conditions.

  5. The effectiveness of a population-based skin cancer screening program: evidence from Germany.

    Science.gov (United States)

    Kaiser, Micha; Schiller, Jörg; Schreckenberger, Christopher

    2017-03-28

    In this paper, we analyze how a nationwide population-based skin cancer screening program (SCS) implemented in Germany in 2008 has impacted the number of hospital discharges following malignant skin neoplasm diagnosis and the malignant melanoma mortality rate per 100,000 inhabitants. Our panel data, drawn from the Eurostat database, cover subregions in 22 European countries, measured at the lowest nomenclature of territorial units for statistics (NUTS) level for 2000-2013. Applying fixed effects methods, we find a significantly positive and robust effect of the German SCS on the number of patients diagnosed with malignant skin neoplasm. However, the program does not significantly influence the melanoma mortality rate. This finding conflicts with the decreased melanoma mortality rate found for the pilot SCS program in northern Germany. Our results indicate that Germany's nationwide SCS program is effective in terms of a higher diagnosis rate for malignant skin neoplasms and thus may contribute to an improvement in the early detection of skin cancer.

  6. Effects of Turmeric (Curcuma longa) on Skin Health: A Systematic Review of the Clinical Evidence.

    Science.gov (United States)

    Vaughn, Alexandra R; Branum, Amy; Sivamani, Raja K

    2016-08-01

    Turmeric (Curcuma longa), a commonly used spice throughout the world, has been shown to exhibit antiinflammatory, antimicrobial, antioxidant, and anti-neoplastic properties. Growing evidence shows that an active component of turmeric, curcumin, may be used medically to treat a variety of dermatologic diseases. This systematic review was conducted to examine the evidence for the use of both topical and ingested turmeric/curcumin to modulate skin health and function. The PubMed and Embase databases were systematically searched for clinical studies involving humans that examined the relationship between products containing turmeric, curcumin, and skin health. A total of 234 articles were uncovered, and a total of 18 studies met inclusion criteria. Nine studies evaluated the effects of ingestion, eight studies evaluated the effects of topical, and one study evaluated the effects of both ingested and topical application of turmeric/curcumin. Skin conditions examined include acne, alopecia, atopic dermatitis, facial photoaging, oral lichen planus, pruritus, psoriasis, radiodermatitis, and vitiligo. Ten studies noted statistically significant improvement in skin disease severity in the turmeric/curcumin treatment groups compared with control groups. Overall, there is early evidence that turmeric/curcumin products and supplements, both oral and topical, may provide therapeutic benefits for skin health. However, currently published studies are limited and further studies will be essential to better evaluate efficacy and the mechanisms involved. Copyright © 2016 John Wiley & Sons, Ltd.

  7. Nonlinear Seebeck and Peltier effects in quantum point contacts

    Energy Technology Data Exchange (ETDEWEB)

    Cipiloglu, M.A.; Turgut, S.; Tomak, M. [Department of Physics, Middle East Technical University, Ankara (Turkey)

    2004-09-01

    The charge and entropy currents across a quantum point contact are expanded as a series in powers of the applied bias voltage and the temperature difference. After that, the expansions of the Seebeck voltage in temperature difference and the Peltier heat in current are obtained. With a suitable choice of the average temperature and chemical potential, the lowest order nonlinear term in both cases appear to be of third order. The behavior of the third-order coefficients in both cases are then investigated for different contact parameters. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Effect of Tissue Inhomogeneity on Nonlinear Propagation of Focused Ultrasound

    Institute of Scientific and Technical Information of China (English)

    LIU Zhen-Bo; FAN Ting-Bo; GUO Xia-Sheng; ZHANG Dong

    2010-01-01

    @@ We study the influence of tissue inhomogeneity on the focused ultrasound based on the phase screen model and the acoustic nonlinear equation.The inhomogeneous tissue is considered as a combination of a homogeneous medium and a phase aberration screen.Six polyethylene(PE)plates with various correlation lengths and standard deviations are made to mimic the inhomogeneity induced by the human body abdominal.Results indicate that the correlation length affects the side lobe structure of the beam pattern; while the standard deviation is associated with the focusing capability.This study provides a theoretical and experimental basis for the development of a precise treatment plan for high intensity focused ultrasound.

  9. Nonlinear Seebeck and Peltier effects in quantum point contacts

    Science.gov (United States)

    Çipilolu, M. A.; Turgut, S.; Tomak, M.

    2004-09-01

    The charge and entropy currents across a quantum point contact are expanded as a series in powers of the applied bias voltage and the temperature difference. After that, the expansions of the Seebeck voltage in temperature difference and the Peltier heat in current are obtained. With a suitable choice of the average temperature and chemical potential, the lowest order nonlinear term in both cases appear to be of third order. The behavior of the third-order coefficients in both cases are then investigated for different contact parameters.

  10. Weak non-linear surface charging effects in electrolytic films

    OpenAIRE

    Dean, D. S.; Horgan, R. R.

    2002-01-01

    A simple model of soap films with nonionic surfactants stabilized by added electrolyte is studied. The model exhibits charge regularization due to the incorporation of a physical mechanism responsible for the formation of a surface charge. We use a Gaussian field theory in the film but the full non-linear surface terms which are then treated at a one-loop level by calculating the mean-field Poisson-Boltzmann solution and then the fluctuations about this solution. We carefully analyze the reno...

  11. Effect of local allergen priming on early, late, delayed-phase, and epicutaneous skin reactions

    NARCIS (Netherlands)

    Weller, FR; Weller, MS; Jansen, HM; deMonchy, JGR

    1996-01-01

    Allergic disease is renected in a chronic inflammatory response to an allergen. It is thought that local allergen priming underlies this chronicity. To assess the effect of allergen priming on the amplitude and histologic effect of the allergic reaction, four sequential, intracutaneous skin tests we

  12. Protective effects of black rice bran against chemically-induced inflammation of mouse skin

    Science.gov (United States)

    We investigated the inhibitory effects of black rice (cv. LK1-3-6-12-1-1) bran against 12-O-tetradecanolylphorbol-13-acetate (TPA)-induced skin edema and 2,4-dinitroflurobenzene (DNFB)-induced allergic contact dermatitis (ACD) in inflammatory mouse models. We also determined the effects of the bran...

  13. Effect of geometric anisotropy on optical nonlinearity enhancement for periodic composites

    Science.gov (United States)

    Yang, Baifeng; Zhang, Chengxiang; Tian, Decheng

    2003-01-01

    The effect of geometric anisotropy on the optical nonlinearity enhancement for the composites with metal or semiconductor spheriodal-shaped particles periodically in an insulating host is investigated. The frequency dependences of effective nonlinear susceptibility are calculated with the Stroud-Hui relation and a series expression of space-dependent electric field in periodic composites. The results show that for both metal-insulator (MI) and semiconductor-insulator (SI) composites, nonlinearity enhancement increases almost to its maximum when the percolation networks of the inclusion phase form. The nonlinearity enhancement increases to its maximum when the composites are transformed into the Boyd-Sipe layered composites. The behavior of the nonlinearity enhancement near the percolation threshold is also investigated. A local minimum appears in the nonlinear optical responses at the percolation threshold for the MI composites. For the SI composites the local minimum appears when the ratio of the bound-electron number density to the effective mass of the electron is large.

  14. Research on Nonlinear Absorption Effect in KDP and 70%-DKDP Crystals

    Directory of Open Access Journals (Sweden)

    Duanliang Wang

    2017-07-01

    Full Text Available Nonlinear optical absorption effect in KDP and 70%-DKDP crystals, which were grown by the conventional temperature cooling method, was systematically studied using picosecond pulse laser excitation. Using open aperture Z-scan measurements, the dependence of nonlinear absorption effect on sample orientations (I, II, and z as well as laser intensity was systematically measured at λ = 1064 and 532 nm. According to the experimental results, the nonlinear absorption effect at λ = 532 nm was confirmed, while at λ = 1064 nm no nonlinear absorption was observed for KDP and 70%-DKDP crystals. In addition, the optical absorption along I- and II-type affected by laser intensity was larger than that along the z-direction. The important nonlinear absorption coefficients β and χ I ( 3 (esu measured along different orientations were exhibited in detail at wavelengths of 1064 nm and 532 nm. The results indicate that nonlinear absorption coefficients increase first and then decrease with the increment of laser intensity for KDP and 70%-DKDP crystals.

  15. Effect of parsley (Petroselinum crispum) on the skin of STZ induced diabetic rats.

    Science.gov (United States)

    Tunali, T; Yarat, A; Yanardağ, R; Ozçelik, F; Ozsoy, O; Ergenekon, G; Emekli, N

    1999-03-01

    Parsley (Petroselinum crispum) is one of the medicinal herbs used by diabetics in Turkey and it has been reported to reduce blood glucose. The purpose of this study therefore was to investigate the effect of feeding parsley on diabetes induced impairments in rat skins. Uncontrolled induced diabetes caused significant increases in nonenzymatic glycosylation of skin proteins, lipid peroxidation and blood glucose. Administration of parsley extract did not inhibit these effects except for the increase in blood glucose. SDS-polyacrylamide gel electrophoresis revealed no significant differences in any protein bands between any of the groups.

  16. Primarily nonlinear effects observed in a driven asymmetrical vibrating wire

    Science.gov (United States)

    Hanson, Roger J.; Macomber, H. Kent; Morrison, Andrew C.; Boucher, Matthew A.

    2005-01-01

    The purpose of the work reported here is to further experimentally explore the wide variety of behaviors exhibited by driven vibrating wires, primarily in the nonlinear regime. When the wire is driven near a resonant frequency, it is found that most such behaviors are significantly affected by the splitting of the resonant frequency and by the existence of a ``characteristic'' axis associated with each split frequency. It is shown that frequency splitting decreases with increasing wire tension and can be altered by twisting. Two methods are described for determining the orientation of characteristic axes. Evidence is provided, with a possible explanation, that each axis has the same orientation everywhere along the wire. Frequency response data exhibiting nonlinear generation of transverse motion perpendicular to the driving direction, hysteresis, linear generation of perpendicular motion (sometimes tubular), and generation of motion at harmonics of the driving frequency are exhibited and discussed. Also reported under seemingly unchanging conditions are abrupt large changes in the harmonic content of the motion that sometimes involve large subharmonics and harmonics thereof. Slow transitions from one stable state of vibration to another and quasiperiodic motions are also exhibited. Possible musical significance is discussed. .

  17. Nonlinear diffraction effects around a surface-piercing structure

    Energy Technology Data Exchange (ETDEWEB)

    Lalli, F.; Mascio, A. Di; Landrini, M. [Istituto Nazionale per Studi ed Esperienze di Architettura Navale, Rome (Italy)

    1995-12-31

    In the present paper the interaction of a wave system with a submerged or surface piercing body is studied. The wave diffraction caused by a cylinder in finite depth water and by a shoal is been computed and the results are compared with analytical solutions and experimental data. The problem is analyzed numerically in the frame of irrotational incompressible flow hypothesis. Both the linearized and the fully nonlinear mathematical models are studied. The numerical solution is gained by means of a mixed panel-desingularized formulation. An explicit time-marching algorithm updates the wave elevation and the potential at the free surface. In all cases, the numerical simulation mirrors the experimental data. In the case of the diffraction around a cylinder, the simulation confirms and extends the theoretical results of the second order analysis (Kriebel 1990, 1992): the linear model yields a very good estimation of the force amplitude acting on the body, while the wave profiles are poorly predicted when compared with the fully nonlinear simulation and the experimental data.

  18. Flavanone silibinin treatment attenuates nitrogen mustard-induced toxic effects in mouse skin

    Science.gov (United States)

    Jain, Anil K; Tewari-Singh, Neera; Inturi, Swetha; Kumar, Dileep; Orlicky, David J; Agarwal, Chapla; White, Carl W; Agarwal, Rajesh

    2015-01-01

    Currently, there is no effective antidote to prevent skin injuries by sulfur mustard (SM) and nitrogen mustard (NM), which are vesicating agents with potential relevance to chemical warfare, terrorist attacks, or industrial/laboratory accidents. Our earlier report has demonstrated the therapeutic efficacy of silibinin, a natural flavanone, in reversing monofunctional alkylating SM analog 2-chloroethyl ethyl sulfide-induced toxic effects in mouse skin. To translate this effect to a bifunctional alkylating vesicant, herein, efficacy studies were carried out with NM. Topical application of silibinin (1 or 2 mg) 30 min after NM exposure on the dorsal skin of male SKH-1 hairless mice significantly decreased NM-induced toxic lesions at 24, 72 or 120 h post-exposure. Specifically, silibinin treatment resulted in dose-dependent reduction of NM-induced increase in epidermal thickness, dead and denuded epidermis, parakeratosis and microvesication. Higher silibinin dose also caused a 79% and 51% reversal in NM-induced increases in myeloperoxidase activity and COX-2 levels, respectively. Furthermore, silibinin completely prevented NM-induced H2A.X phosphorylation, indicating reversal of DNA damage which could be an oxidative DNA damage as evidenced by high levels of 8-oxodG in NM-exposed mouse skin that was significantly reversed by silibinin. Together, these findings suggest that attenuation of NM-induced skin injury by silibinin is due to its effects on the pathways associated with DNA damage, inflammation, vesication and oxidative stress. In conclusion, results presented here support the optimization of silibinin as an effective treatment of skin injury by vesicants. PMID:25791923

  19. [Skin slice used as a model for investigating acupuncture effects].

    Science.gov (United States)

    Wang, Li-Na; Schwarz, Wolfgang; Gu, Quan-Bao; Ding, Guang-Hong

    2009-10-01

    To establish an acupoint-connective tissue model for studying the mechanism of acupuncture by using in vitro patch clamp technique in the rat skin slices. The local connective tissue under the corium of "Housanli" (ST 36) area from SD rat was acutely and bluntly separated and fixed in a chamber filled with artificial incubation solution. Mast cells in the prepared connective tissue slice were labeled by toluidine blue (TB) or neutral red (NR). The whole-cell current of mast cells responding to pressure stimulation applied through a patch pipette was recorded in rat slices derived from acupoint ST 36 area by using in vitro patch-clamp technique. 1) After staining with TB and NR, the labeled mast cells were found to distribute in the extracellular matrix of the connective tissue samples, and their degranulation phenomenon could be seen clearly. 2) The whole-cell current of mast cells in response to mechanical stress stimulation was successfully recorded in the connective tissue slices of the rat acupoint ST 36 area. The cellular membrane currents increased evidently when pressure gradients of -30, -60 or -90 cmH2O were applied to the recorded mast cells. The connective tissue slice from the rat ST 36 area may be used as a model for investigating the peripheral mechanism of acupuncture by combining the microtechniques and electrophysiological techniques. The results obtained in this model prove for the first time by electrophysiology that the mast cells in the connective tissue are probably involved in the transduction process of the mechanical signal from acupuncture stimulation. This new model provides a base for investigating the characters of the cells, collagen fibers, proteoglycans, etc. and their interactions in the acupoint connective tissue in the future.

  20. Mechanistic effects of long-term ultraviolet B irradiation induce epidermal and dermal changes in human skin xenografts.

    Science.gov (United States)

    Hachiya, Akira; Sriwiriyanont, Penkanok; Fujimura, Tsutomu; Ohuchi, Atsushi; Kitahara, Takashi; Takema, Yoshinori; Kitzmiller, William J; Visscher, Marty O; Tsuboi, Ryoji; Boissy, Raymond E

    2009-02-01

    UVB irradiation has been reported to induce photoaging and suppress systemic immune function that could lead to photocarcinogenesis. However, because of the paucity of an UVB-induced photodamaged skin model, precise and temporal mechanism(s) underlying the deleterious effects of long-term UVB exposure on human skin have yet to be delineated. In this study, we established a model using human skin xenografted onto severe combined immunodeficient mice, which were subsequently challenged by repeated UVB irradiation for 6 weeks. Three-dimensional optical image analysis of skin replicas and noninvasive biophysical measurements illustrated a significant increase in skin surface roughness, similar to premature photoaging, and a significant loss of skin elasticity after long-term UVB exposure. Resembling authentically aged skin, UVB-exposed samples exhibited significant increases in epithelial keratins (K6, K16, K17), elastins, and matrix metalloproteinases (MMP-1, MMP-9, MMP-12) as well as degradation of collagens (I, IV, VII). The UVB-induced deterioration of fibrous keratin intermediate filaments was also observed in the stratum corneum. Additionally, similarities in gene expression patterns between our model and chronologically aged skin substantiated the plausible relationship between photodamage and chronological age. Furthermore, severe skin photodamage was observed when neutralizing antibodies against TIMP-1, an endogenous inhibitor of MMPs, were administered during the UVB exposure regimen. Taken together, these findings suggest that our skin xenograft model recapitulates premature photoaged skin and provides a comprehensive tool with which to assess the deleterious effects of UVB irradiation.

  1. A new topical panthenol-containing emollient: Results from two randomized controlled studies assessing its skin moisturization and barrier restoration potential, and the effect on skin microflora.

    Science.gov (United States)

    Stettler, Hans; Kurka, Peter; Lunau, Nathalie; Manger, Caroline; Böhling, Arne; Bielfeldt, Stephan; Wilhelm, Klaus-Peter; Dähnhardt-Pfeiffer, Stephan; Dähnhardt, Dorothee; Brill, Florian H H; Lenz, Holger

    2017-03-01

    Two randomized, intra-individual comparison studies were performed in healthy subjects to evaluate the skin moisturization and barrier restoration potential of a new topical panthenol-containing emollient (NTP-CE) (Study 1), and its effect on skin microflora (Study 2). In Study 1 (N = 23), two skin areas, one challenged with 0.5% sodium dodecyl sulfate (SDS) solution and one unchallenged, were treated with NTP-CE for 3 weeks. Transepidermal water loss (TEWL), skin hydration, and intercellular lipid lamellae (ICLL) organization were measured at regular intervals during the study. In Study 2 (N = 20), quantitative bacterial cultures were obtained over 6 h from a skin area undergoing wash stress with 10% SDS with subsequent single application of NTP-CE. In Study 1, mean AUC for TEWL reduction from baseline was more pronounced with NTP-CE compared with control (-168.36 vs. -123.38 g/m(2)/h, p = 0.023). NTP-CE use was also associated with statistically significant improvements in stratum corneum hydration and an increase in mean ICLL length from baseline (day 22: 120.61 vs. 35.85 nm/1000 nm(2), p skin hydration without negatively influencing bacterial viability.

  2. Effect of temperature on the effective mass and the neutron skin of nuclei

    CERN Document Server

    Yüksel, E; Bozkurt, K; Colò, G

    2014-01-01

    We study the finite temperature Hartree-Fock-BCS approximation for selected Sn nuclei with zero-range Skyrme forces. Hartree Fock BCS approximation allows for a straightforward interpretation of the results since it involves $u$ and $v$'s which are not matrices as in HFB. Pairing transitions from superfluid to the normal state are studied with respect to the temperature. The temperature dependence of the nuclear radii and neutron skin are also analyzed. An increase of proton and neutron radii is obtained in neutron rich nuclei especially above the critical temperature. Using different Skyrme energy functionals, a correlation between the effective mass in symmetric nuclear matter and the critical temperature is found. The temperature dependence of the nucleon effective mass is also investigated, showing that proton and neutron effective masses display different behavior below and above the critical temperature.

  3. NONLINEAR VIBRATION FOR MODERATE THICKNESS RECTANGULAR CRACKED PLATES INCLUDING COUPLED EFFECT OF ELASTIC FOUNDATION

    Institute of Scientific and Technical Information of China (English)

    XIAO Yong-gang; FU Yi-ming; ZHA Xu-dong

    2005-01-01

    Based on Reissner plate theory and Hamilton variational principle, the nonlinear equations of motion were derived for the moderate thickness rectangular plates with transverse surface penetrating crack on the two-parameter foundation. Under the condition of free boundary, a set of trial functions satisfying all boundary conditions and crack's continuous conditions were proposed. By employing the Galerkin method and the harmonic balance method, the nonlinear vibration equations were solved and the nonlinear vibration behaviors of the plate were analyzed. In numerical computation, the effects of the different location and depth of crack, the different structural parameters of plates and the different physical parameters of foundation on the nonlinear amplitude frequency response curves of the plate were discussed.

  4. Radiation effect on viscous flow of a nanofluid and heat transfer over a nonlinearly stretching sheet.

    Science.gov (United States)

    Hady, Fekry M; Ibrahim, Fouad S; Abdel-Gaied, Sahar M; Eid, Mohamed R

    2012-04-22

    In this work, we study the flow and heat transfer characteristics of a viscous nanofluid over a nonlinearly stretching sheet in the presence of thermal radiation, included in the energy equation, and variable wall temperature. A similarity transformation was used to transform the governing partial differential equations to a system of nonlinear ordinary differential equations. An efficient numerical shooting technique with a fourth-order Runge-Kutta scheme was used to obtain the solution of the boundary value problem. The variations of dimensionless surface temperature, as well as flow and heat-transfer characteristics with the governing dimensionless parameters of the problem, which include the nanoparticle volume fraction ϕ, the nonlinearly stretching sheet parameter n, the thermal radiation parameter NR, and the viscous dissipation parameter Ec, were graphed and tabulated. Excellent validation of the present numerical results has been achieved with the earlier nonlinearly stretching sheet problem of Cortell for local Nusselt number without taking the effect of nanoparticles.

  5. Nonlinear continuous-wave optical propagation in nematic liquid crystals: Interplay between reorientational and thermal effects

    Science.gov (United States)

    Alberucci, Alessandro; Laudyn, Urszula A.; Piccardi, Armando; Kwasny, Michał; Klus, Bartlomiej; Karpierz, Mirosław A.; Assanto, Gaetano

    2017-07-01

    We investigate nonlinear optical propagation of continuous-wave (CW) beams in bulk nematic liquid crystals. We thoroughly analyze the competing roles of reorientational and thermal nonlinearity with reference to self-focusing/defocusing and, eventually, the formation of nonlinear diffraction-free wavepackets, the so-called spatial optical solitons. To this extent we refer to dye-doped nematic liquid crystals in planar cells excited by a single CW beam in the highly nonlocal limit. To adjust the relative weight between the two nonlinear responses, we employ two distinct wavelengths, inside and outside the absorption band of the dye, respectively. Different concentrations of the dye are considered in order to enhance the thermal effect. The theoretical analysis is complemented by numerical simulations in the highly nonlocal approximation based on a semi-analytic approach. Theoretical results are finally compared to experimental results in the Nematic Liquid Crystals (NLC) 4-trans-4'-n-hexylcyclohexylisothiocyanatobenzene (6CHBT) doped with Sudan Blue dye.

  6. Theory of plasmonic effects in nonlinear optics: the case of graphene

    CERN Document Server

    Rostami, Habib; Polini, Marco

    2016-01-01

    We develop a microscopic large-$N$ theory of electron-electron interaction corrections to multi-legged Feynman diagrams describing second- and third-order nonlinear response functions. Our theory, which reduces to the well-known random phase approximation in the linear-response limit, is completely general and is useful to understand all second- and third-order nonlinear effects, including harmonic generation, wave mixing, and photon drag. We apply our theoretical framework to the case of graphene, by carrying out microscopic calculations of the second- and third-order nonlinear response functions of an interacting two-dimensional (2D) gas of massless Dirac fermions. We compare our results with recent measurements, where all-optical launching of graphene plasmons has been achieved by virtue of the finiteness of the quasi-homogeneous second-order nonlinear response of this inversion-symmetric 2D material.

  7. Synthetic Effect of Vivid Shark Skin and Polymer Additive on Drag Reduction Reinforcement

    Directory of Open Access Journals (Sweden)

    Huawei Chen

    2014-06-01

    Full Text Available Natural shark skin has a well-demonstrated drag reduction function, which is mainly owing to its microscopic structure and mucus on the body surface. In order to improve drag reduction, it is necessary to integrate microscopic drag reduction structure and drag reduction agent. In this study, two hybrid approaches to synthetically combine vivid shark skin and polymer additive, namely, long-chain grafting and controllable polymer diffusion, were proposed and attempted to mimic such hierarchical topography of shark skin without waste of polymer additive. Grafting mechanism and optimization of diffusion port were investigated to improve the efficiency of the polymer additive. Superior drag reduction effects were validated, and the combined effect was also clarified through comparison between drag reduction experiments.

  8. Iatrogenic effects of photoprotection recommendations on skin cancer development, vitamin D levels, and general health.

    Science.gov (United States)

    Reddy, Kavitha K; Gilchrest, Barbara A

    2011-01-01

    Ultraviolet (UV) radiation is an established carcinogen that causes skin cancers and other cutaneous photodamage. Vitamin D is produced in the skin after UV exposure and may also be obtained from dietary and supplemental sources. The effect of recommendations for UV protection, as well as for very large vitamin D supplements, and possible adverse effects of both are explored. Current evidence supports the conclusion that protection from UV radiation reduces the incidence of skin cancers and photodamage, but generally does not compromise vitamin D status or lead to iatrogenic disease. Conversely, risks of maintaining very high vitamin D levels have not been adequately studied. Vitamin D obtained from diet and supplements is functionally identical to that produced after UV exposure, and is a more reliable and quantifiable source of the vitamin.

  9. Transcriptomic analysis of bottlenose dolphin (Tursiops truncatus) skin biopsies to assess the effects of emerging contaminants.

    Science.gov (United States)

    Lunardi, Denise; Abelli, Luigi; Panti, Cristina; Marsili, Letizia; Fossi, Maria Cristina; Mancia, Annalaura

    2016-03-01

    Chemicals discovered in water at levels that may be significantly different than expected are referred to as contaminants of emerging concern (CECs) because the risk to environmental health posed by their occurrence/frequency is still unknown. The worldwide distributed compounds perfluorooctanoic acid (PFOA) and bisphenol A (BPA) may fall into this category due to effects on endocrine receptors. We applied an ex vivo assay using small slices of bioptic skin from the bottlenose dolphin, Tursiops truncatus, cultured and treated for 24 h with different PFOA or BPA concentrations to analyze global gene expression. RNA was labeled and hybridized to a species-specific oligomicroarray. The skin transcriptome held information on the contaminant exposure, potentially predictive about long-term effects on health, being the genes affected involved in immunity modulation, response to stress, lipid homeostasis, and development. The transcriptomic signature of dolphin skin could be therefore relevant as classifier for a specific contaminant.

  10. Light-induced nonlinear effects on dispersion relation of ultracold Bose gas

    Institute of Scientific and Technical Information of China (English)

    胡正峰; 杜春光; 李师群

    2003-01-01

    We have investigated the optical properties of A-configuration ultracold dense Bose gas interacting with two laser pulses, which usually result in electromagnetically induced transparency. With the nonrelativistic quantum electrodynamics and taking into account the atomic dipole-dipole interaction and local field effect, we have derived the Maxwell-Bloch equations of the system. The dispersion relation of an ultracold Bose gas has been obtained and the light-induced nonlinear effects have been analysed. The light-induced nonlinear effects are different from the effects induced by two-body collision of Bose-Einstein condensation atoms which have a frequency shift of transparent window.

  11. Light—induced nonlinear effects of dispersion relation of ultracold Bose gas

    Institute of Scientific and Technical Information of China (English)

    HuZheng-Feng; DuChunGuang; LiShi-Qun

    2003-01-01

    We have investigated the optical properties of A-configuration ultracold dense Bose gas interacting with two laser pulses, which usually result in electromagnetically induced transparency. With the nonrelativistic quantum electrodynamics and taking into account the atomic dipole-dipole interaction and local field effect, we have derived the Maxwell-Bloch equations of the system. The dispersion relation of an ultracold Bose gas has been obtained and the light-induced nonlinear effects have been analysed. The light-induced nonlinear effects are different from the effects induced by two-body collision of Bose-Einstein condensation atoms which have a frequency shift of transparent window.

  12. Non-linear effects of soda taxes on consumption and weight outcomes.

    Science.gov (United States)

    Fletcher, Jason M; Frisvold, David E; Tefft, Nathan

    2015-05-01

    The potential health impacts of imposing large taxes on soda to improve population health have been of interest for over a decade. As estimates of the effects of existing soda taxes with low rates suggest little health improvements, recent proposals suggest that large taxes may be effective in reducing weight because of non-linear consumption responses or threshold effects. This paper tests this hypothesis in two ways. First, we estimate non-linear effects of taxes using the range of current rates. Second, we leverage the sudden, relatively large soda tax increase in two states during the early 1990s combined with new synthetic control methods useful for comparative case studies. Our findings suggest virtually no evidence of non-linear or threshold effects.

  13. Zinc pyrithione in alcohol-based products for skin antisepsis: persistence of antimicrobial effects.

    Science.gov (United States)

    Guthery, Eugene; Seal, Lawton A; Anderson, Edward L

    2005-02-01

    Alcohol-based products for skin antisepsis have a long history of safety and efficacy in the United States and abroad. However, alcohol alone lacks the required antimicrobial persistence to provide for the sustained periods of skin antisepsis desired in the clinical environment. Therefore, alcohol-based products must have a preservative agent such as iodine/iodophor compounds, chlorhexidine gluconate, or zinc pyrithione, to extend its antimicrobial effects. Iodine, iodophors, and chlorhexidine gluconate are well-characterized antimicrobials and preservatives. The thrust of our effort was to examine the characteristics of the lesser-known zinc pyrithione and to evaluate its utility as a preservative in the formulation of alcohol-based products for skin antisepsis. This work includes a literature review of current zinc pyrithione applications in drugs and cosmetics, a safety and toxicity evaluation, consideration of the proposed mechanisms of antimicrobial action, in vitro and in vivo efficacy data, and a discussion of the mechanisms that confer the desired antimicrobial persistence. In addition, alcohol-based, zinc pyrithione-preserved, commercially available products of skin antisepsis are compared with other commercially available antimicrobials used for skin antisepsis and with additional alcohol-based products with different preservatives. The authors' conclusion is that zinc pyrithione is not only a safe and effective antimicrobial but that its use in certain alcohol-based formulations results in antimicrobial efficacy exceeding that of iodine and chlorhexidine gluconate.

  14. Effect of compositions in nanostructured lipid carriers (NLC on skin hydration and occlusion

    Directory of Open Access Journals (Sweden)

    Loo CH

    2012-12-01

    Full Text Available CH Loo,1,2 M Basri,2 R Ismail,1 HLN Lau,1 BA Tejo,2 MS Kanthimathi,3 HA Hassan,1 YM Choo11Malaysian Palm Oil Board, Bandar Baru Bangi, 2Department of Chemistry, Universiti Putra Malaysia, Serdang, 3Department of Molecular Medicine, University of Malaya, Kuala Lumpur, MalaysiaPurpose: To study the effects of varying lipid concentrations, lipid and oil ratio, and the addition of propylene glycol and lecithin on the long-term physical stability of nanostructured lipid nanocarriers (NLC, skin hydration, and transepidermal water loss.Methods: The various NLC formulations (A1–A5 were prepared and their particle size, zeta potential, viscosity, and stability were analyzed. The formulations were applied on the forearms of the 20 female volunteers (one forearm of each volunteer was left untreated as a control. The subjects stayed for 30 minutes in a conditioned room with their forearms uncovered to let the skin adapt to the temperature (22°C ± 2°C and humidity (50% ± 2% of the room. Skin hydration and skin occlusion were recorded at day one (before treatment and day seven (after treatment. Three measurements for skin hydration and skin occlusion were performed in each testing area.Results: NLC formulations with the highest lipid concentration, highest solid lipid concentration, and additional propylene glycol (formulations A1, A2, and A5 showed higher physical stability than other formulations. The addition of propylene glycol into an NLC system helped to reduce the particle size of the NLC and enhanced its long-term physical stability. All the NLC formulations were found to significantly increase skin hydration compared to the untreated controls within 7 days. All NLC formulations exhibited occlusive properties as they reduced the transepidermal water loss within 7 days. This effect was more pronounced with the addition of propylene glycol or lecithin into an NLC formulation, whereby at least 60% reduction in transepidermal water loss was observed

  15. The influence of nonlinear effects on the spectral efficiency of multiinput antenna systems

    Directory of Open Access Journals (Sweden)

    Vishniakova J. V.

    2015-08-01

    Full Text Available The analysis technique and design algorithm are proposed for multiinput antenna systems, based on the mathematical model developed. The technique and algorithm described allow the analysis of a wide class of multiinput systems, in particular, MIMO systems, reconfigurable multiantenna systems, multiinput systems with nonlinear components and devices. The paper presents numerical analysis results of the intermodulation interference effect on the spectral efficiency of a multiinput system with nonlinear elements in receiving antennas, obtained using the methods, algorithms and software products developed. It is shown that in the nonlinear system intermodulation interferences appear, and the spectral efficiency of the data transmission system decays near the operating frequency due to the appearance of additional combinational components in the frequency response of the system. This effect depends on the degree of nonlinearity, radiated power, the level of interfering signals. Based on the results obtained, it was concluded that the presence of nonlinear elements and devices must be taken into account in the design and analysis processes of multiinput multiantenna systems, considering the specific types of those nonlinearities.

  16. Tannins from Potentilla officinalis display antiinflammatory effects in the UV erythema test and on atopic skin.

    Science.gov (United States)

    Hoffmann, Julia; Wölfle, Ute; Schempp, Christoph M; Casetti, Federica

    2016-09-01

    Rich in tannins, the rhizome of Potentilla officinalis (PO) has traditionally been used in the topical treatment of inflammatory disorders of the skin and mucous membranes. The objective of the present study was to examine the antiinflammatory effects of PO in the UV erythema test as well as in patients with atopic skin. Using the UV erythema test, the antiinflammatory effects of a PO extract (2 %) - compared to 1 % hydrocortisone acetate - were assessed in a randomized, prospective, placebo-controlled double-blind study of 40 healthy volunteers. In the context of a prospective non-controlled trial, the efficacy and tolerability of 2 % PO cream (applied to defined test areas twice daily for two weeks) was evaluated in twelve adults and twelve children with atopic skin using a partial SCORAD. In addition, the effects on the degree of erythema in the test areas was measured photometrically. In the UV erythema test, PO cream significantly reduced the erythema index compared to the vehicle. The antiinflammatory effects of PO cream were comparable to those of 1 % hydrocortisone acetate cream. The clinical study with atopic patients revealed a significant reduction in the partial SCORAD as well as erythema in the test areas. No adverse events were recorded. PO cream displays antiinflammatory effects in vivo. It is effective in and well tolerated by patients with atopic skin. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  17. Skin tolerance and effectiveness of two hand decontamination procedures in everyday hospital use.

    Science.gov (United States)

    Winnefeld, M; Richard, M A; Drancourt, M; Grob, J J

    2000-09-01

    Hand decontamination is crucial to control nosocomial infections. The utility of hand decontamination is related not only to its antimicrobial effectiveness, but also to its acceptability by hospital staff. We aimed to assess skin tolerance and antimicrobial effects of two widely accepted hand hygiene measures under in-use conditions. Fifty-two nurses were randomly assigned for an 8-day period to either an alcohol-based disinfectant or a hand wash with a non-antiseptic soap. At baseline and at the end of the test period, microbiological hand samples were obtained both before and after a hand hygiene procedure, and skin tolerance was assessed using clinical scores and measurement of transepidermal water loss. Self-assessment of skin condition and grade of skin damage worsened significantly more in the group using soap than in the group using alcoholic disinfectant (P = 0.004 and P = 0.01, respectively). The alcohol-based rinse was significantly more effective than liquid soap in removing transient contaminant micro-organisms (P = 0.016). Twenty of 50 hand washes with non-antiseptic soap apparently resulted in bacterial contamination of the hands. At the end of the study, the total bacterial count increased with the increasing number of hand washes in the soap group (P = 0.003), and with the degree of skin damage (P = 0.005) in the antiseptic group. In everyday hospital practice, alcohol-based disinfectant is more effective and better tolerated than non-antiseptic soap; soap is at risk of spreading contamination; and skin comfort strongly influences the number and the quality of hand hygiene procedures.

  18. Effect of four-dimensional variational data assimilation in case of nonlinear instability

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The effect of four-dimensional variational data assimilation on the reduction of the forecast errors is investigated for both stable and unstable flows. Numerical results show that the effect is generally positive. Particularly,its effect is much more significant in the presence of nonlinear instability

  19. Effects of Locally Applied Glycerol and Xylitol on the Hydration, Barrier Function and Morphological Parameters of the Skin.

    Science.gov (United States)

    Korponyai, Csilla; Szél, Edit; Behány, Zoltán; Varga, Erika; Mohos, Gábor; Dura, Ágnes; Dikstein, Shabtay; Kemény, Lajos; Erős, Gábor

    2017-02-08

    Glycerol and xylitol hydrate the skin and improve its barrier function over a short period. We studied the effects of glycerol and xylitol on the physiological properties and morphology of the skin after longer-term application. Twelve volunteers with dry skin were examined. Three areas on the arms were determined. Area 1 served as untreated control. The vehicle was applied to area 2, while area 3 was treated twice daily with a formulation containing glycerol (5%) and xylitol (5%) for 14 days. Transepidermal water loss (TEWL), hydration and biomechanical properties of the skin were monitored. Biopsies were taken for routine histology and immunohistochemistry for filaggrin and matrix metalloproteinase-1 (MMP-1). The polyols increased the skin hydration and protein quantity of filaggrin, elevated the interdigitation index, decreased the TEWL and improved the biomechanical properties of the skin, but did not change the protein expression of MMP-1. A combination of glycerol and xylitol can be useful additional therapy for dry skin.

  20. Complementary effects of antioxidants and sunscreens in reducing UV-induced skin damage as demonstrated by skin biomarker expression.

    Science.gov (United States)

    Oresajo, Christian; Yatskayer, Margarita; Galdi, Angelike; Foltis, Peter; Pillai, Sreekumar

    2010-06-01

    UV-exposure of the skin causes oxidative stress, leading to inflammatory reactions and premature skin aging. Sunscreens protect by absorbing or reflecting UV on the skin surface. Antioxidants provide protection by quenching UV-induced reactive oxygen species inside skin. To evaluate the complementary photoprotective benefits of formulas containing either an antioxidant complex of Cassia alata leaf extract or a combination of the antioxidant complex and sunscreens on normal healthy volunteers using biomarkers of skin damage. Each formula and a placebo control were applied separately to selected areas on the lower back of 10 individuals for 4 consecutive days. On Day 4, the control and three test sites were exposed to 5 x MED (minimal erythemal dose) of solar-simulated UV-irradiation (UVR). On Day 5, 4-mm punch biopsies were collected from the four exposed sites and a control site (untreated, unexposed) for immunohistochemistry. Exposure to 5 x MED demonstrated significant damage as assessed by thymine dimer formation, MMP-9 and p53 protein expression on untreated exposed skin. The formula containing sunscreens + the antioxidant complex was the most protective, followed by the formula with the antioxidant alone. The study demonstrated that a combination of antioxidants and sunscreens complement each other, resulting in superior photoprotection.

  1. Effects of weak nonlinearity on the dispersion relation and frequency band-gaps of a periodic Bernoulli-Euler beam.

    Science.gov (United States)

    Sorokin, Vladislav S; Thomsen, Jon Juel

    2016-02-01

    The paper deals with analytically predicting the effects of weak nonlinearity on the dispersion relation and frequency band-gaps of a periodic Bernoulli-Euler beam performing bending oscillations. Two cases are considered: (i) large transverse deflections, where nonlinear (true) curvature, nonlinear material and nonlinear inertia owing to longitudinal motions of the beam are taken into account, and (ii) mid-plane stretching nonlinearity. A novel approach is employed, the method of varying amplitudes. As a result, the isolated as well as combined effects of the considered sources of nonlinearities are revealed. It is shown that nonlinear inertia has the most substantial impact on the dispersion relation of a non-uniform beam by removing all frequency band-gaps. Explanations of the revealed effects are suggested, and validated by experiments and numerical simulation.

  2. Effect of a lipid-rich emollient containing ceramide 3 in experimentally induced skin barrier dysfunction.

    Science.gov (United States)

    Kucharekova, M; Schalkwijk, J; Van De Kerkhof, P C M; Van De Valk, P G M

    2002-06-01

    In the present study we compared the effect of a ceramide 3-containing emollient (Locobase(R) Repair) with a control emollient (vaselinum album/cremor lanette ana) and untreated damaged skin using clinical, bioengineering and immunohistochemical methods in two different models of experimentally induced skin barrier dysfunction. In model A (n = 13) skin barrier dysfunction was inflicted at three investigation sites by tape stripping. In model B (n = 13) the volunteers were patch tested at three investigation sites with sodium dodecyl sulphate (0.2%) for 4 h a day for 4 consecutive days. The investigation sites were treated once a day with the above-mentioned agents. Irritant reaction was assessed daily by erythema scoring and measurements of transepidermal water loss (TEWL). After 5D, punch biopsies were taken from all sites. Immunohistochemical assessment was carried out with respect to epidermal proliferation, epidermal differentiation and Langerhans cells. Tape stripping resulted in an erythematous reaction and an increase of TEWL associated with up-regulation of cycling cells, involucrin and expression of cytokeratin 16. At day 4, ceramide 3-containing emollient significantly decreased (p emollient significantly prevented erythema, increase of TEWL and cycling cells at day 4 compared to the untreated site. In summary, the present study demonstrated that both tested emollients improve skin barrier in different conditions compared to the untreated skin. There is some indication that formulations containing skin-related lipids might be of benefit in barrier disruption following tape stripping. Different models and clinical trials are needed to establish the usefulness in specific conditions of emollients containing skin-related lipids.

  3. Nonlinear effects of dark energy clustering beyond the acoustic scales

    Energy Technology Data Exchange (ETDEWEB)

    Anselmi, Stefano [Department of Physics/CERCA/ISO, Case Western Reserve University, Cleveland, OH 44106-7079 (United States); Nacir, Diana López [The Abdus Salam International Center for Theoretical Physics, Strada costiera 11, I-34151 Trieste (Italy); Sefusatti, Emiliano, E-mail: stefano.anselmi@case.edu, E-mail: dlopez_n@ictp.it, E-mail: emiliano.sefusatti@brera.inaf.it [INAF - Osservatorio Astronomico di Brera, via E. Bianchi 46, I-23807 Merate (Saint Lucia) (Italy)

    2014-07-01

    We extend the resummation method of Anselmi and Pietroni (2012) to compute the total density power spectrum in models of quintessence characterized by a vanishing speed of sound. For standard ΛCDM cosmologies, this resummation scheme allows predictions with an accuracy at the few percent level beyond the range of scales where acoustic oscillations are present, therefore comparable to other, common numerical tools. In addition, our theoretical approach indicates an approximate but valuable and simple relation between the power spectra for standard quintessence models and models where scalar field perturbations appear at all scales. This, in turn, provides an educated guess for the prediction of nonlinear growth in models with generic speed of sound, particularly valuable since no numerical results are yet available.

  4. The effect of nonlinearity in relativistic nucleon–nucleon potential

    Indian Academy of Sciences (India)

    B B Sahu; S K Singh; M Bhuyan; S K Patra

    2014-04-01

    A simple form for nucleon–nucleon (NN) potential is introduced as an alternative to the popular M3Y form using the relativistic mean field theory (RMFT) with the non-linear terms in -meson for the first time. In contrast to theM3Y form, the new interaction becomes exactly zero at a finite distance and the expressions are analogous with the M3Y terms. Further, its applicability is examined by the study of proton and cluster radioactivity by folding it with the RMFT-densities of the cluster and daughter nuclei to obtain the optical potential in the region of proton-rich nuclides just above the double magic core 100Sn. The results obtained were found comparable with the widely used M3Y interactions.

  5. A NONLINEAR MATHEMATICAL MODEL FOR ASTHMA: EFFECT OF ENVIRONMENTAL POLLUTION

    Directory of Open Access Journals (Sweden)

    NARESHA RAM

    2009-04-01

    Full Text Available In this paper, we explore a nonlinear mathematical model to study the spread of asthma due to inhaled pollutants from industry as well as tobacco smoke from smokers in a variable size population. The model is analyzed using stability theory of differential equations and computer simulation. It is shown that with an increase in the level of air pollutants concentration, the asthmatic (diseased population increases. It is also shown that along with pollutants present in the environment, smoking (active or passive also helps in the spread of asthma. Moreover, with the increase in the rate of interaction between susceptibles and smokers, the persistence of the spread of asthma is higher. A numerical study of the model is also performed to see the role of certain key parameters on the spread of asthma and to support the analytical results.

  6. Nonlinear Zel'dovich effect: Parametric amplification from medium rotation

    CERN Document Server

    Faccio, Daniele

    2016-01-01

    The interaction of light with rotating media has attracted recent interest for both fundamental and applied studies including rotational Doppler shift measurements. It is also possible to obtain amplification through the scattering of light with orbital angular momentum from a rotating and absorbing cylinder, as proposed by Zel'dovich more than 40 years ago. This amplification mechanism has never been observed experimentally yet has connections to other fields such as Penrose superradiance in rotating black holes. Here we propose a nonlinear optics system whereby incident light carrying orbital angular momentum drives parametric interaction in a rotating medium. The crystal rotation is shown to take the phase-mismatched parametric interaction with negligible energy exchange at zero rotation to amplification for sufficiently large rotation rates. The amplification is shown to result from breaking of anti-PT symmetry induced by the medium rotation.

  7. Connected cruise control: modelling, delay effects, and nonlinear behaviour

    Science.gov (United States)

    Orosz, Gábor

    2016-08-01

    Connected vehicle systems (CVS) are considered in this paper where vehicles exchange information using wireless vehicle-to-vehicle (V2V) communication. The concept of connected cruise control (CCC) is established that allows control design at the level of individual vehicles while exploiting V2V connectivity. Due to its high level of modularity the proposed design can be applied to large heterogeneous traffic systems. The dynamics of a simple CVS is analysed in detail while taking into account nonlinearities in the vehicle dynamics as well as in the controller. Time delays that arise due to intermittencies and packet drops in the communication channels are also incorporated. The results are summarised using stability charts which allow one to select control gains to maintain stability and ensure disturbance attenuation when the delay is below a critical value.

  8. Nonlinear Zel'dovich Effect: Parametric Amplification from Medium Rotation

    Science.gov (United States)

    Faccio, Daniele; Wright, Ewan M.

    2017-03-01

    The interaction of light with rotating media has attracted recent interest for both fundamental and applied studies including rotational Doppler shift measurements. It is also possible to obtain amplification through the scattering of light with orbital angular momentum from a rotating and absorbing cylinder, as proposed by Zel'dovich more than forty years ago. This amplification mechanism has never been observed experimentally yet has connections to other fields such as Penrose superradiance in rotating black holes. Here we propose a nonlinear optics system whereby incident light carrying orbital angular momentum drives parametric interaction in a rotating medium. The crystal rotation is shown to take the phase-mismatched parametric interaction with negligible energy exchange at zero rotation to amplification for sufficiently large rotation rates. The amplification is shown to result from breaking of anti-P T symmetry induced by the medium rotation.

  9. The topical use of non-thermal dielectric barrier discharge (DBD): nitric oxide related effects on human skin.

    Science.gov (United States)

    Heuer, Kiara; Hoffmanns, Martin A; Demir, Erhan; Baldus, Sabrina; Volkmar, Christine M; Röhle, Mirco; Fuchs, Paul C; Awakowicz, Peter; Suschek, Christoph V; Opländer, Christian

    2015-01-30

    Dielectric barrier discharge (DBD) devices generate air plasma above the skin containing active and reactive species including nitric oxide (NO). Since NO plays an essential role in skin physiology, a topical application of NO by plasma may be useful in the treatment of skin infections, impaired microcirculation and wound healing. Thus, after safety assessments of plasma treatment using human skin specimen and substitutes, NO-penetration through the epidermis, the loading of skin tissue with NO-derivates in vitro and the effects on human skin in vivo were determined. After the plasma treatment (0-60 min) of skin specimen or reconstructed epidermis no damaging effects were found (TUNEL/MTT). By Franz diffusion cell experiments plasma-induced NO penetration through epidermis and dermal enrichment with NO related species (nitrite 6-fold, nitrate 7-fold, nitrosothiols 30-fold) were observed. Furthermore, skin surface was acidified (~pH 2.7) by plasma treatment (90 s). Plasma application on the forearms of volunteers increased microcirculation fourfold in 1-2 mm and twofold in 6-8 mm depth in the treated skin areas. Regarding the NO-loading effects, skin acidification and increase in dermal microcirculation, plasma devices represent promising tools against chronic/infected wounds. However, efficacy of plasma treatment needs to be quantified in further studies and clinical trials.

  10. The deceptive nature of UVA-tanning versus the modest protective effects of UVB-tanning on human skin

    Science.gov (United States)

    Miyamura, Yoshinori; Coelho, Sergio G.; Schlenz, Kathrin; Batzer, Jan; Smuda, Christoph; Choi, Wonseon; Brenner, Michaela; Passeron, Thierry; Zhang, Guofeng; Kolbe, Ludger; Wolber, Rainer; Hearing, Vincent J.

    2010-01-01

    Summary The relationship between human skin pigmentation and protection from ultraviolet (UV) radiation is an important element underlying differences in skin carcinogenesis rates. The association between UV damage and the risk of skin cancer is clear, yet a strategic balance in exposure to UV needs to be met. Dark skin is protected from UV-induced DNA damage significantly more than light skin due to the constitutively higher pigmentation but an as yet unresolved and important question is what photoprotective benefit, if any, is afforded by facultative pigmentation (i.e. a tan induced by UV exposure). To address that and to compare the effects of various wavelengths of UV, we repetitively exposed human skin to suberythemal doses of UVA and/or UVB over 2 weeks after which a challenge dose of UVA&UVB was given. Although visual skin pigmentation (tanning) elicited by the different UV exposure protocols was similar, the melanin content and UV-protective effects against DNA damage in UVB-tanned skin (but not in UVA-tanned skin) were significantly higher. UVA-induced tans seem to result from the photooxidation of existing melanin and its precursors with some redistribution of pigment granules while UVB stimulates melanocytes to up-regulate melanin synthesis and increases pigmentation coverage, effects that are synergistically stimulated in UVA and UVB-exposed skin. Thus, UVA-tanning contributes essentially no photoprotection, although all types of UV-induced tanning result in DNA and cellular damage which can eventually lead to photocarcinogenesis. PMID:20979596

  11. Protective effect of red orange extract supplementation against UV-induced skin damages: photoaging and solar lentigines.

    Science.gov (United States)

    Puglia, Carmelo; Offerta, Alessia; Saija, Antonella; Trombetta, Domenico; Venera, Cardile

    2014-06-01

    Exposure of the skin to solar ultraviolet (UV) radiations causes important oxidative damages that result in clinical and hystopathological changes, contributing to premature skin aging. Hyperpigmented lesions, also known as age spots, are one of the most visible alterations in skin photoaging. Skin is naturally equipped with antioxidant systems against UV-induced ROS generation; however, these antioxidant defenses are not completely efficient during exposure to sunlight. Oral antioxidants are able to counteract the harmful effects of UV radiation and to strengthen the physiological skin antioxidant defenses. The present study was performed to evaluate the in vivo skin photo-protecting and anti-aging effects of a red orange (Citrus sinensis varieties Moro, Tarocco and Sanguinello) extract supplementation. Previous studies showed that red orange extracts possess strong in vitro free radical scavenging/antioxidant activity and photo-protective effects on human skin. The photo-protective effects of red orange extract intake against UV-induced skin erythema and melanin production in solar lentigo was evaluated on healthy volunteers by an objective instrumental method (reflectance spectrophotometry). Data obtained from in vivo studies showed that supplementation of red orange extract (100 mg/daily) for 15 days brought a significant reduction in the UV-induced skin erythema degree. Moreover, skin age spots pigmentation (melanin content) decreased from 27% to 7% when subjects were exposed to solar lamp during red orange extract supplementation. Red orange extract intake can strengthen physiological antioxidant skin defenses, protecting skin from the damaging processes involved in photo-aging and leading to an improvement in skin appearance and pigmentation. © 2014 Wiley Periodicals, Inc.

  12. Titanium Dioxide Nanoparticle Penetration into the Skin and Effects on HaCaT Cells.

    Science.gov (United States)

    Crosera, Matteo; Prodi, Andrea; Mauro, Marcella; Pelin, Marco; Florio, Chiara; Bellomo, Francesca; Adami, Gianpiero; Apostoli, Pietro; De Palma, Giuseppe; Bovenzi, Massimo; Campanini, Marco; Filon, Francesca Larese

    2015-08-07

    Titanium dioxide nanoparticles (TiO2NPs) suspensions (concentration 1.0 g/L) in synthetic sweat solution were applied on Franz cells for 24 h using intact and needle-abraded human skin. Titanium content into skin and receiving phases was determined. Cytotoxicity (MTT, AlamarBlue(®) and propidium iodide, PI, uptake assays) was evaluated on HaCat keratinocytes after 24 h, 48 h, and seven days of exposure. After 24 h of exposure, no titanium was detectable in receiving solutions for both intact and damaged skin. Titanium was found in the epidermal layer after 24 h of exposure (0.47 ± 0.33 μg/cm(2)) while in the dermal layer, the concentration was below the limit of detection. Damaged skin, in its whole, has shown a similar concentration (0.53 ± 0.26 μg/cm(2)). Cytotoxicity studies on HaCaT cells demonstrated that TiO2NPs induced cytotoxic effects only at very high concentrations, reducing cell viability after seven days of exposure with EC50s of 8.8 × 10(-4) M (MTT assay), 3.8 × 10(-5) M (AlamarBlue(®) assay), and 7.6 × 10(-4) M (PI uptake, index of a necrotic cell death). Our study demonstrated that TiO2NPs cannot permeate intact and damaged skin and can be found only in the stratum corneum and epidermis. Moreover, the low cytotoxic effect observed on human HaCaT keratinocytes suggests that these nano-compounds have a potential toxic effect at the skin level only after long-term exposure.

  13. Contracture of skin graft in human burns: effect of artificial dermis.

    Science.gov (United States)

    Hur, Gi-Yeun; Seo, Dong-Kook; Lee, Jong-Wook

    2014-12-01

    Skin grafts with an artificial dermis have been widely used as a part of the efforts to minimize contractures and reduce donor-site scars. We conducted a prospective randomized clinical trial to study the effect of a dermal substitute by measuring the size of the graft after surgery for months. The artificial dermis (Matriderm, Dr. Suwelack Skin and Health Care AG, Billerbeck, Germany) was applied in combination with a split-thickness autograft in 40 patients with acute burn wounds or scar reconstruction. Demographic and medical data were collected on each patient. We directly measured the graft size by using a transparent two-ply film (Visitrak Grid, Smith & Nephew Wound Management, Inc, Largo, FL, USA) intraoperatively and 1, 2, 3, and 6 months postoperatively. For effective data comparison, the size of the graft at the time of surgery was taken to be "100%." Then, the size in each phase was estimated in percentage (%). During the 1st month, the average size was 89%. The figure decreased to 86% and 82% in the 2nd and 3rd months, respectively. In the 6th month, it slightly rebounded to 85% but failed to return to the original state. The size of patients with acute burns was smaller than the size of scar patients as follows: 85-91% in the 2nd month, 81-87% in the 3rd month, and 85-96% in the 6th month. This study examined the progress of skin grafts through the measurement of graft size in the human body. The grafted skin underwent contracture and remodeling for 3-6 months. In terms of skin contraction, an acute burn was more serious than scar reconstruction. The use of an artificial dermis that contains elastin is very effective from the functional and esthetic perspective by minimizing contractures and enhancing skin elasticity. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

  14. Titanium Dioxide Nanoparticle Penetration into the Skin and Effects on HaCaT Cells

    Directory of Open Access Journals (Sweden)

    Matteo Crosera

    2015-08-01

    Full Text Available Titanium dioxide nanoparticles (TiO2NPs suspensions (concentration 1.0 g/L in synthetic sweat solution were applied on Franz cells for 24 h using intact and needle-abraded human skin. Titanium content into skin and receiving phases was determined. Cytotoxicity (MTT, AlamarBlue® and propidium iodide, PI, uptake assays was evaluated on HaCat keratinocytes after 24 h, 48 h, and seven days of exposure. After 24 h of exposure, no titanium was detectable in receiving solutions for both intact and damaged skin. Titanium was found in the epidermal layer after 24 h of exposure (0.47 ± 0.33 μg/cm2 while in the dermal layer, the concentration was below the limit of detection. Damaged skin, in its whole, has shown a similar concentration (0.53 ± 0.26 μg/cm2. Cytotoxicity studies on HaCaT cells demonstrated that TiO2NPs induced cytotoxic effects only at very high concentrations, reducing cell viability after seven days of exposure with EC50s of 8.8 × 10−4 M (MTT assay, 3.8 × 10−5 M (AlamarBlue® assay, and 7.6 × 10−4 M (PI uptake, index of a necrotic cell death. Our study demonstrated that TiO2NPs cannot permeate intact and damaged skin and can be found only in the stratum corneum and epidermis. Moreover, the low cytotoxic effect observed on human HaCaT keratinocytes suggests that these nano-compounds have a potential toxic effect at the skin level only after long-term exposure.

  15. Effect of Residual Stress on Divergence Instability of Rectangular Microplate Subjected to Nonlinear Electrostatic Pressure

    Directory of Open Access Journals (Sweden)

    Ghader Rezazadeh

    2007-07-01

    Full Text Available In this paper, the effect of residual stress on divergence instability of a rectangular microplate subjected to a nonlinear electrostatic pressure for different geometrical properties has been presented. After deriving the governing equation and using of Step-by-Step Linearization Method (SSLM, the governing nonlinear equation has been linearized. By applying the finite difference method (FDM to a rectangular mesh, the linearized equation has been discretized. The results show, residual stresses have considerable effects on Pull-in phenomena. Tensile residual stresses increase pull-in voltage and compressive decrease it. The effect of different geometrical properties on divergence instability has also been studied.

  16. The Simulation Analysis of Nonlinear for a Power Amplifier with Memory Effects

    Directory of Open Access Journals (Sweden)

    Lv. Jinqiu

    2014-09-01

    Full Text Available For the nonlinear distortion problem of current power amplifiers (PAs with memory effects, we use goal programming to present a memoryless predistorter matrix model based on limiting baseband predistortion technique, and the normalized mean squared error (NMSE is limited in a satisfactory range while the output power is maximum. Then we propose a nonlinear power amplifier with memory effects based on back propagation neural network (BPNN with three tapped delay nodes and six single hidden layer nodes, which is single input - dual output. Simulation results show that the method proposed in this paper makes the experimental precision higher. Further, the linearization effect of power amplifiers becomes better.

  17. Second order optical nonlinearity of graphene due to electric quadrupole and magnetic dipole effects

    Science.gov (United States)

    Cheng, J. L.; Vermeulen, N.; Sipe, J. E.

    2017-01-01

    We present a practical scheme to separate the contributions of the electric quadrupole-like and the magnetic dipole-like effects to the forbidden second order optical nonlinear response of graphene, and give analytic expressions for the second order optical conductivities, calculated from the independent particle approximation, with relaxation described in a phenomenological way. We predict strong second order nonlinear effects, including second harmonic generation, photon drag, and difference frequency generation. We discuss in detail the controllability of these effects by tuning the chemical potential, taking advantage of the dominant role played by interband optical transitions in the response. PMID:28262762

  18. The pretreatment effect of chemical skin penetration enhancers in transdermal drug delivery using iontophoresis.

    Science.gov (United States)

    Choi, E H; Lee, S H; Ahn, S K; Hwang, S M

    1999-01-01

    The transdermal drug delivery (TDD) system has largely been divided into physical, biochemical and chemical methods. Recently, combinations of these methods were introduced for more effective delivery with less side effects. We performed this study to identify the effectiveness and mechanism of TDD using the physical method, 'iontophoresis', plus the chemical method, 'pretreatment with chemical enhancer'. The action sites of chemical enhancers in the stratum corneum (SC) were observed by electron microscope. We also studied whether this combined method synergistically impaired the skin barrier. To confirm the synergistic effect on skin penetration by this combined method, we measured the blood glucose level after insulin iontophoresis following a chemical enhancer pretreatment in rabbits. The results were that (1) dilatation of the intercellular lipid layers of the SC and lacunae was prominent in pretreatment with chemical enhancers inducing high transepidermal water loss (TEWL); (2) the skin barrier impairment, with repeated treatments showing an increased TEWL and also epidermal proliferation, was increased with the chemical enhancers that showed a high TEWL immediately after treatment; (3) the combination of chemical enhancer pretreatment and iontophoresis showed no synergistic impairment of the skin barrier, and (4) the chemical enhancer pretreatment with greater impairment of the skin barrier could increase the delivery of insulin by iontophoresis. The results showed that a combination of chemical enhancer pretreatment and iontophoresis could deliver drugs more effectively than iontophoresis alone. Our proposed theory is that iontophoretic drug delivery may be easier through the dilated intercellular spaces of the SC which have a lower electrical impedance following the chemical enhancer pretreatment. Because the effect and the side effects in the combination are decided by the chemical enhancer rather than iontophoresis, the development of proper chemical

  19. Effects of niacin restriction on sirtuin and PARP responses to photodamage in human skin.

    Directory of Open Access Journals (Sweden)

    Claudia A Benavente

    Full Text Available Sirtuins (SIRTs and poly(ADP-ribose polymerases (PARPs, NAD(+-dependent enzymes, link cellular energy status with responses to environmental stresses. Skin is frequently exposed to the DNA damaging effects of UV irradiation, a known etiology in skin cancer. Thus, understanding the defense mechanisms in response to UV, including the role of SIRTs and PARPs, may be important in developing skin cancer prevention strategies. Here, we report expression of the seven SIRT family members in human skin. SIRTs gene expressions are progressively upregulated in A431 epidermoid carcinoma cells (SIRTs1 and 3, actinic keratoses (SIRTs 2, 3, 5, 6, and 7 and squamous cell carcinoma (SIRTs 1-7. Photodamage induces dynamic changes in SIRT expression with upregulation of both SIRT1 and SIRT4 mRNAs. Specific losses of SIRT proteins occur early after photodamage followed by accumulation later, especially for SIRT4. Niacin restriction, which decreases NAD(+, the sirtuin substrate, results in an increase in acetylated proteins, upregulation of SIRTs 2 and 4, increased inherent DNA damage, alterations in SIRT responses to photodamage, abrogation of PARP activation following photodamage, and increased sensitivity to photodamage that is completely reversed by repleting niacin. These data support the hypothesis that SIRTs and PARPs play important roles in resistance to photodamage and identify specific SIRTs that respond to photodamage and may be targets for skin cancer prevention.

  20. Phototoxic and modulatory effects of natural products from the skin of Rhinella jimi (Stevaux, 2002

    Directory of Open Access Journals (Sweden)

    Samuel V. Brito

    2012-02-01

    Full Text Available The skin of amphibians possesses a large diversity of biologically active compounds that are associated with the natural defenses of these animals against pathogens. Five different extracts and fractions were obtained from the skin of Rhinella jimi: methanol extract (ME, methanol fractions (MF, chloroform extract of methanol extract (CF, aqueous alkaloid fraction (AAF and aqueous non-alkaloid fraction (ANAF. All fractions were evaluated with respect to their antibiotic modifying activity in standard bacterial strains and multiresistant clinical isolates. Antagonism was detected with kanamycin and gentamicin when combined with substances obtained from the skin of R. jimi. Phototoxic activity was observed in the methanol and chlorophorm fractions, as well as the aqueous non-alkaloid fraction. The antagonistic action was apparently associated with the protection afforded by the bacterial populations that inhabit the skin of this amphibian, preventing colonization by pathogenic fungi. The phototoxic activity demonstrated by natural products from the skin of R. jimi showed an interruption of the bacterial growth after UV exposure. This could indicate an antibacterial effect activated by the UV light, opening a path for carrying the attack by pathogenic fungi, causing the disease related with the amphibian decline.

  1. Human skin penetration and local effects of topical nano zinc oxide after occlusion and barrier impairment.

    Science.gov (United States)

    Leite-Silva, V R; Sanchez, W Y; Studier, H; Liu, D C; Mohammed, Y H; Holmes, A M; Ryan, E M; Haridass, I N; Chandrasekaran, N C; Becker, W; Grice, J E; Benson, H A E; Roberts, M S

    2016-07-01

    Public health concerns continue to exist over the safety of zinc oxide nanoparticles that are commonly used in sunscreen formulations. In this work, we assessed the effects of two conditions which may be encountered in everyday sunscreen use, occlusion and a compromised skin barrier, on the penetration and local toxicity of two topically applied zinc oxide nanoparticle products. Caprylic/capric triglyceride (CCT) suspensions of commercially used zinc oxide nanoparticles, either uncoated or with a silane coating, were applied to intact and barrier impaired skin of volunteers, without and with occlusion for a period of six hours. The exposure time was chosen to simulate normal in-use conditions. Multiphoton tomography with fluorescence lifetime imaging was used to noninvasively assess zinc oxide penetration and cellular metabolic changes that could be indicative of toxicity. We found that zinc oxide nanoparticles did not penetrate into the viable epidermis of intact or barrier impaired skin of volunteers, without or with occlusion. We also observed no apparent toxicity in the viable epidermis below the application sites. These findings were validated by ex vivo human skin studies in which zinc penetration was assessed by multiphoton tomography with fluorescence lifetime imaging as well as Zinpyr-1 staining and toxicity was assessed by MTS assays in zinc oxide treated skin cryosections. In conclusion, applications of zinc oxide nanoparticles under occlusive in-use conditions to volunteers are not associated with any measurable zinc oxide penetration into, or local toxicity in the viable epidermis below the application site.

  2. Development of effective skin cancer treatment and prevention in xeroderma pigmentosum.

    Science.gov (United States)

    Lambert, W Clark; Lambert, Muriel W

    2015-01-01

    Xeroderma pigmentosum (XP) is a rare, recessively transmitted genetic disease characterized by increasingly marked dyspigmentation and xerosis (dryness) of sun-exposed tissues, especially skin. Skin cancers characteristically develop in sun-exposed sites at very much earlier ages than in the general population; these are often multiple and hundreds or even thousands may develop. Eight complementation groups have been identified. Seven groups, XP-A…G, are associated with defective genes encoding proteins involved in the nucleotide excision DNA repair (NER) pathway that recognizes and excises mutagenic changes induced in DNA by sunlight; the eighth group, XP-V, is associated with defective translesion synthesis (TLS) bypassing such alterations. The dyspigmentation, xerosis and eventually carcinogenesis in XP patients appear to be due to their cells' failure to respond properly to these mutagenic DNA alterations, leading to mutations in skin cells. A subset of cases, especially those in some complementation groups, may develop neurological degeneration, which may be severe. However, in most XP patients, in the past the multiple skin cancers have led to death at an early age due to either metastases or sepsis. Using either topical 5-fluorouracil or imiquimod, we have developed a protocol that effectively prevents most skin cancer development in XP patients. © 2014 The American Society of Photobiology.

  3. THERAPEUTIC EFFECT OF SOLASODINE RHAMNOSYL GLYCOSIDES FOR LARGE SKIN CANCERS: TWO CLINICAL CASES

    Directory of Open Access Journals (Sweden)

    Bill E. Cham

    2012-01-01

    Full Text Available Solasodine rhamnosyl glycosides (BEC are a new class of antineoplastics, the efficiency of which administered via intravenous, intraperitoneal, and intratumoral routes is higher than that of many other antitumor agents. Early investigations have established the efficiency of topical BEC applications as a treatment option for non-melanoma skin cancers. There have recently been two clinical cases that count in favor of the fact that the cream formulation Curaderm containing BEC has a very high efficacy in the treatment of large non-melanoma skin cancers that are incurable by other existing methods. Also, Curaderm treatment shows a splendid cosmetic effect

  4. Effect of reduction time on third order optical nonlinearity of reduced graphene oxide

    Science.gov (United States)

    Sreeja, V. G.; Vinitha, G.; Reshmi, R.; Anila, E. I.; Jayaraj, M. K.

    2017-04-01

    We report the influence of reduction time on structural, linear and nonlinear optical properties of reduced graphene oxide (rGO) thin films synthesized by spin coating method. We observed that the structural, linear and nonlinear optical properties can be tuned with reduction time in GO is due to the increased structural ordering because of the restoration of sp2 carbon atoms with the time of reduction. The nonlinear absorption studies by open aperture Z-scan technique exhibited a saturable absorption. The nonlinear refraction studies showed the self de focusing nature of rGO by closed aperture Z scan technique. The nonlinear absorption coefficient and saturation intensity varies with the time for reduction of GO which is attributed to the depletion of valence band and the conduction band filling effect. Our results emphasize duration for reduction of GO dependent optical nonlinearity of rGO thin films to a great extent and explore its applications Q switched mode locking laser systems for generating ultra short laser pulses and in optical sensors. The rGO coated films were characterized by X-Ray diffraction method (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, UV-Vis absorption spectroscopy (UV-Vis), Photoluminescence (PL) and Scanning electron microscope (SEM) measurements.

  5. Nonspecific vasodilatation during transdermal iontophoresis—the effect of voltage over the skin

    NARCIS (Netherlands)

    Droog, E.J.; Sjöberg, F.

    2003-01-01

    We used laser Doppler perfusion imaging (LDPI) to study nonspecific vasodilatation during iontophoresis. In iontophoresis studies, nonspecific vasodilatation occurs as a result either of galvanic currents or of the applied voltage over the skin. We made dose–response measurements to study the effect

  6. Effects of palmitoyl-KVK-L-ascorbic acid on skin wrinkles and pigmentation.

    Science.gov (United States)

    Kim, Hyeong Mi; An, Hyo Sun; Bae, Jung-Soo; Kim, Jung Yun; Choi, Chi Ho; Kim, Ju Yeon; Lim, Joo Hyuck; Choi, Joon-Hun; Song, Hyunnam; Moon, Sung Ho; Park, Young Jun; Chang, Shin-Jae; Choi, Sun Young

    2017-07-01

    Wrinkle formation and abnormal pigmentation are major clinical alterations associated with skin aging. As the aim of our study was to investigate the effects of palmitoyl-KVK-L-ascorbic acid on skin aging, the anti-wrinkle and depigmentation effects of palmitoyl-KVK-L-ascorbic acid were evaluated by measuring collagen expression in dermal fibroblast cells and inhibition of melanogenesis in B16F1 cells, respectively. The anti-aging effect of palmitoyl-KVK-L-ascorbic acid cream was also evaluated against a placebo cream in a clinical trial. Our results confirmed that the expression of type Ι collagen in dermal fibroblast cells treated with palmitoyl-KVK-L-ascorbic acid (0.1-4 μg/mL) increased in a dose-dependent manner. In B16F1 cells, treatment with 20 μg/mL palmitoyl-KVK-L-ascorbic acid reduced the melanin content by approximately 20% compared to alpha-melanocyte stimulating hormone treatment. In the clinical trial, application of palmitoyl-KVK-L-ascorbic acid cream led to an improvement in skin roughness and lightness in 12 and 8 weeks, respectively. Our data show that palmitoyl-KVK-L-ascorbic acid is an effective anti-aging agent that reduces wrinkles and abnormal skin pigmentation.

  7. Temperature effect on the static behaviour of adhesively-bonded metal skin to composite stiffener

    NARCIS (Netherlands)

    Teixeira De Freitas, S.; Sinke, J.

    2015-01-01

    The purpose of this research is to study the effect of temperature on the static behavior of an hybrid structure consisting of adhesively bonded Fiber Metal Laminate skin to a composite stiffener. This hybrid structure was tested using stiffener pull-off tests, which is a typical set-up used to simu

  8. Nonspecific vasodilatation during transdermal iontophoresis—the effect of voltage over the skin

    NARCIS (Netherlands)

    Droog, E.J.; Sjöberg, F.

    2003-01-01

    We used laser Doppler perfusion imaging (LDPI) to study nonspecific vasodilatation during iontophoresis. In iontophoresis studies, nonspecific vasodilatation occurs as a result either of galvanic currents or of the applied voltage over the skin. We made dose–response measurements to study the effect

  9. Effects of oral administration of glucosylceramide on gene expression changes in hairless mouse skin: comparison of whole skin, epidermis, and dermis.

    Science.gov (United States)

    Takatori, Ryo; Le Vu, Phuong; Iwamoto, Taku; Satsu, Hideo; Totsuka, Mamoru; Chida, Kazuhiro; Shimizu, Makoto

    2013-01-01

    The beneficial effects of dietary glucosylceramide on the barrier function of the skin have been increasingly reported, but the entire mechanism has not been clarified. By DNA microarray, we investigated changes in gene expression in hairless mouse skin when a damage-inducing AD diet and a glucosylceramide diet (GluCer) were imposed. GluCer administration potentially suppressed the upregulation of six genes and the downregulation of four genes in the AD group. Examination of the epidermal and/or dermal expression of Npr3, Cyp17a1, Col1a1, S100a9, Sprr2f, Apol7a, Tppp, and Scd3 revealed responses of various parts of the skin to the diets. In normal hairless mice, GluCer administration induced an increase in the dermal expression of Cyp17a1 and the epidermal expression of Tppp, and a decrease in the epidermal expression of S100a9. Our results provide information on gene expression not only in whole skin but also in the epidermis and dermis that should prove useful in the search for the mechanisms underlying the effects of GluCer on damaged and normal skin.

  10. Skin Diseases: Skin Health and Skin Diseases

    Science.gov (United States)

    Skip Navigation Bar Home Current Issue Past Issues Skin Diseases Skin Health and Skin Diseases Past Issues / Fall 2008 Table of Contents ... acne to wrinkles Did you know that your skin is the largest organ of your body? It ...

  11. Pulse testing in the presence of wellbore storage and skin effects

    Energy Technology Data Exchange (ETDEWEB)

    Ogbe, D.O.; Brigham, W.E.

    1984-08-01

    A pulse test is conducted by creating a series of short-time pressure transients in an active (pulsing) well and recording the observed pressure response at an observation (responding) well. Using the pressure response and flow rate data, the transmissivity and storativity of the tested formation can be determined. Like any other pressure transient data, the pulse-test response is significantly influenced by wellbore storage and skin effects. The purpose of this research is to examine the influence of wellbore storage and skin effects on interference testing in general and on pulse-testing in particular, and to present the type curves and procedures for designing and analyzing pulse-test data when wellbore storage and skin effects are active at either the responding well or the pulsing well. A mathematical model for interference testing was developed by solving the diffusivity equation for radial flow of a single-phase, slightly compressible fluid in an infinitely large, homogeneous reservoir. When wellbore storage and skin effects are present in a pulse test, the observed response amplitude is attenuated and the time lag is inflated. Consequently, neglecting wellbore storage and skin effects in a pulse test causes the calculated storativity to be over-estimated and the transmissivity to be under-estimated. The error can be as high as 30%. New correlations and procedures are developed for correcting the pulse response amplitude and time lag for wellbore storage effects. Using these correlations, it is possible to correct the wellbore storage-dominated response amplitude and time lag to within 3% of their expected values without wellbore storage, and in turn to calculate the corresponding transmissivity and storativity. Worked examples are presented to illustrate how to use the new correction techniques. 45 references.

  12. Chemical and engineering approaches to enable organic field-effect transistors for electronic skin applications.

    Science.gov (United States)

    Sokolov, Anatoliy N; Tee, Benjamin C-K; Bettinger, Christopher J; Tok, Jeffrey B-H; Bao, Zhenan

    2012-03-20

    Skin is the body's largest organ and is responsible for the transduction of a vast amount of information. This conformable material simultaneously collects signals from external stimuli that translate into information such as pressure, pain, and temperature. The development of an electronic material, inspired by the complexity of this organ is a tremendous, unrealized engineering challenge. However, the advent of carbon-based electronics may offer a potential solution to this long-standing problem. In this Account, we describe the use of an organic field-effect transistor (OFET) architecture to transduce mechanical and chemical stimuli into electrical signals. In developing this mimic of human skin, we thought of the sensory elements of the OFET as analogous to the various layers and constituents of skin. In this fashion, each layer of the OFET can be optimized to carry out a specific recognition function. The separation of multimodal sensing among the components of the OFET may be considered a "divide and conquer" approach, where the electronic skin (e-skin) can take advantage of the optimized chemistry and materials properties of each layer. This design of a novel microstructured gate dielectric has led to unprecedented sensitivity for tactile pressure events. Typically, pressure-sensitive components within electronic configurations have suffered from a lack of sensitivity or long mechanical relaxation times often associated with elastomeric materials. Within our method, these components are directly compatible with OFETs and have achieved the highest reported sensitivity to date. Moreover, the tactile sensors operate on a time scale comparable with human skin, making them ideal candidates for integration as synthetic skin devices. The methodology is compatible with large-scale fabrication and employs simple, commercially available elastomers. The design of materials within the semiconductor layer has led to the incorporation of selectivity and sensitivity within

  13. Electrets in soft materials: nonlinearity, size effects, and giant electromechanical coupling.

    Science.gov (United States)

    Deng, Qian; Liu, Liping; Sharma, Pradeep

    2014-07-01

    Development of soft electromechanical materials is critical for several tantalizing applications such as soft robots and stretchable electronics, among others. Soft nonpiezoelectric materials can be coaxed to behave like piezoelectrics by merely embedding charges and dipoles in their interior and assuring some elastic heterogeneity. Such so-called electret materials have been experimentally shown to exhibit very large electromechanical coupling. In this work, we derive rigorous nonlinear expressions that relate effective electromechanical coupling to the creation of electret materials. In contrast to the existing models, we are able to both qualitatively and quantitatively capture the known experimental results on the nonlinear response of electret materials. Furthermore, we show that the presence of another form of electromechanical coupling, flexoelectricity, leads to size effects that dramatically alter the electromechanical response at submicron feature sizes. One of our key conclusions is that nonlinear deformation (prevalent in soft materials) significantly enhances the flexoelectric response and hence the aforementioned size effects.

  14. Imprint of non-linear effects on HI intensity mapping on large scales

    Science.gov (United States)

    Umeh, Obinna

    2017-06-01

    Intensity mapping of the HI brightness temperature provides a unique way of tracing large-scale structures of the Universe up to the largest possible scales. This is achieved by using a low angular resolution radio telescopes to detect emission line from cosmic neutral Hydrogen in the post-reionization Universe. We use general relativistic perturbation theory techniques to derive for the first time the full expression for the HI brightness temperature up to third order in perturbation theory without making any plane-parallel approximation. We use this result and the renormalization prescription for biased tracers to study the impact of nonlinear effects on the power spectrum of HI brightness temperature both in real and redshift space. We show how mode coupling at nonlinear order due to nonlinear bias parameters and redshift space distortion terms modulate the power spectrum on large scales. The large scale modulation may be understood to be due to the effective bias parameter and effective shot noise.

  15. Experimental investigation of nonlinear optical properties of Ag nanoparticles: Effects of size quantization

    Science.gov (United States)

    Sato, Rodrigo; Ohnuma, Masato; Oyoshi, Keiji; Takeda, Yoshihiko

    2014-09-01

    The effects of size quantization on the nonlinear optical response of Ag nanoparticles are experimentally studied by spectroscopic ellipsometry and femtosecond spectroscopic pump-and-probe techniques. In the vicinity of a localized surface-plasmon resonance (2.0-3.5 eV), we have investigated the optical nonlinearity of Ag particles embedded in silica glass for particle diameters ranging from 3.0 to 16 nm. The intrinsic third-order optical susceptibility χm(3) of Ag particles exhibited significant spectral and size dependences. These results are explained as quantum and dielectric confinements and are compared to the results of theoretical quantum finite-size effects calculation for metallic particles. In light of these results, we discuss the contribution of interband transitions to the size dependence of χm(3). Quantum size effects lead to an increase in nonlinearity in small Ag particles.

  16. Correction of non-linearity effects in detectors for electron spectroscopy

    CERN Document Server

    Mannella, N; Kay, A W; Nambu, A; Gresch, T; Yang, S H; Mun, B S; Bussat, J M; Rosenhahn, A; Fadley, C S

    2004-01-01

    Using photoemission intensities and a detection system employed by many groups in the electron spectroscopy community as an example, we have quantitatively characterized and corrected detector non-linearity effects over the full dynamic range of the system. Non-linearity effects are found to be important whenever measuring relative peak intensities accurately is important, even in the low-countrate regime. This includes, for example, performing quantitative analyses for surface contaminants or sample bulk stoichiometries, where the peak intensities involved can differ by one or two orders of magnitude, and thus could occupy a significant portion of the detector dynamic range. Two successful procedures for correcting non-linearity effects are presented. The first one yields directly the detector efficiency by measuring a flat-background reference intensity as a function of incident x-ray flux, while the second one determines the detector response from a least-squares analysis of broad-scan survey spectra at di...

  17. Effects of breathing patterns and light exercise on linear and nonlinear heart rate variability.

    Science.gov (United States)

    Weippert, Matthias; Behrens, Kristin; Rieger, Annika; Kumar, Mohit; Behrens, Martin

    2015-08-01

    Despite their use in cardiac risk stratification, the physiological meaning of nonlinear heart rate variability (HRV) measures is not well understood. The aim of this study was to elucidate effects of breathing frequency, tidal volume, and light exercise on nonlinear HRV and to determine associations with traditional HRV indices. R-R intervals, blood pressure, minute ventilation, breathing frequency, and respiratory gas concentrations were measured in 24 healthy male volunteers during 7 conditions: voluntary breathing at rest, and metronome guided breathing (0.1, 0.2 and 0.4 Hz) during rest, and cycling, respectively. The effect of physical load was significant for heart rate (HR; p effect of load and breathing pattern was evident. Correlations to traditional HRV indices were modest (r from -0.14 to -0.67, p exercise does not significantly affect short-time HRV nonlinear indices, respiratory activity has to be considered as a potential contributor at rest and during light dynamic exercise.

  18. Effectiveness of three surgical alcohol-based hand rubs on skin flora

    OpenAIRE

    Zandiyeh, Mitra; Roshanaei, Ghodratollah

    2015-01-01

    Background: It is proved that surgical hand disinfectant contains alcohol, and has favorable properties such as strong and rapid antibacterial effect, ease of application, and suitable effect on skin. Therefore, nowadays use of them has been gradually replacing traditional surgical hand scrub with antibacterial soap. Hence, several domestic and imported products are available to the healthcare facilities in Iran. This study was done in order to determine the antibacterial effect of Decosept, ...

  19. Non-linear effects in transition edge sensors for X-ray detection

    Energy Technology Data Exchange (ETDEWEB)

    Bandler, S.R. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)]. E-mail: sbandler@milkyway.gsfc.nasa.gov; Figueroa-Feliciano, E. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Iyomoto, N. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kelley, R.L. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Kilbourne, C.A. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Murphy, K.D. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Porter, F.S. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Saab, T. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Sadleir, J. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2006-04-15

    In a microcalorimeter that uses a transition-edge sensor to detect energy depositions, the small signal energy resolution improves with decreasing heat capacity. This improvement remains true up to the point where non-linear and saturation effects become significant. This happens when the energy deposition causes a significant change in the sensor resistance. Not only does the signal size become a non-linear function of the energy deposited, but also the noise becomes non-stationary over the duration of the pulse. Algorithms have been developed that can calculate the optimal performance given this non-linear behavior that typically requires significant processing and calibration work-both of which are impractical for space missions. We have investigated the relative importance of the various non-linear effects, with the hope that a computationally simple transformation can overcome the largest of the non-linear and non-stationary effects, producing a highly linear 'gain' for pulse-height versus energy, and close to the best energy resolution at all energies when using a Wiener filter.

  20. Nonlinear effects in propagation of radiation of X-ray free-electron lasers

    Science.gov (United States)

    Nosik, V. L.

    2016-05-01

    Nonlinear effects accompanying the propagation of high-intensity beams of X-ray free-electron lasers are considered. It is shown that the X-ray wave field in the crystal significantly changes due to the formation of "hollow" atomic shells as a result of the photoelectric effect.

  1. Computing effective properties of nonlinear structures exposed to strong high-frequency loading at multiple frequencies

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel

    2006-01-01

    Effects of strong high-frequency excitation at multiple frequencies (multi-HFE) are analyzed for a class of generally nonlinear systems. The effects are illustrated for a simple pendulum system with a vibrating support, and for a parametrically excited flexible beam. For the latter, theoretical...

  2. Cross-polarized wave generation by effective cubic nonlinear optical interaction.

    Science.gov (United States)

    Petrov, G I; Albert, O; Etchepare, J; Saltiel, S M

    2001-03-15

    A new cubic nonlinear optical effect in which a linearly polarized wave propagating in a single quadratic medium is converted into a wave that is cross polarized to the input wave is observed in BBO crystal. The effect is explained by cascading of two different second-order processes: second-harmonic generation and difference frequency mixing.

  3. The effective wavenumber of a pre-stressed nonlinear microvoided composite

    Energy Technology Data Exchange (ETDEWEB)

    Parnell, W J; Abrahams, I D, E-mail: William.Parnell@manchester.ac.uk [School of Mathematics, Alan Turing Building, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom)

    2011-01-01

    By using nonlinear elasticity and a modified version of classical multiple scattering theory we derive an explicit form for the effective wavenumber for horizontally polarized shear (SH) elastic waves propagating through a pre-stressed inhomogeneous material consisting of well-separated cylindrical voids embedded in a neo-Hookean rubber host phase. The resulting effective (incremental) antiplane shear modulus is thus also derived.

  4. Temperature dependent nonlinear Hall effect in macroscopic Si-MOS antidot array

    OpenAIRE

    Kuntsevich, A. Yu.; Shupltetsov, A. V.; Nunuparov, M. S.

    2015-01-01

    By measuring magnetoresistance and Hall effect in classically moderate perpendicular magnetic field in Si-MOSFET-type macroscopic antidot array we found a novel effect: nonlinear with field, temperature- and density-dependent Hall resistivity. We discuss qualitative explanation of the phenomenon and suggest that it might originate from strong temperature dependence of the resistivity and mobility in the shells of the antidots.

  5. The effects of brief cognitive-behaviour therapy for pathological skin picking: A randomized comparison to wait-list control.

    Science.gov (United States)

    Schuck, Kathrin; Keijsers, Ger P J; Rinck, Mike

    2011-01-01

    Thirty-four college students suffering from pathological skin picking were randomly assigned to a four-session cognitive-behavioural treatment (n=17) or a waiting-list condition (n=17). Severity of skin picking, psycho-social impact of skin picking, strength of skin-picking-related dysfunctional cognitions, and severity of skin injury were measured at pre-, post-, and two-months follow-up assessment. Participants in the treatment condition showed a significantly larger reduction on all measured variables in comparison to the waiting-list condition. The obtained effect sizes for the outcome measures were large, ranging from .90 to 1.89. Treatment effects were maintained at follow-up. In conclusion, cognitive-behavioural therapy, even in brief form, constitutes an adequate treatment option for pathological skin-picking behaviour.

  6. The role of natural and UV-induced skin pigmentation on low-fluence IPL-induced side effects

    DEFF Research Database (Denmark)

    Thaysen-Petersen, Daniel; Lin, Jennifer Y; Nash, Jf

    2014-01-01

    were randomized to receive 0 or 8 solar simulated ultraviolet radiation (UVR) exposures of consecutively increasing Standard Erythema Doses (2-4 SED). Each block was subdivided into four sites, randomized to receive IPL of 0, 7, 8, or 10 J/cm(2) , once a week for 3 weeks. Biopsies were taken 16...... of cellular pigment-markers was not influenced by IPL exposure, neither in constitutive nor in facultative pigmented skin. Clinical appearance of biopsy wounds was unaffected by IPL exposure. CONCLUSION: The prevalence and intensity of low-fluence IPL-induced adverse skin effects depended on IPL dose and skin...... disproportionately. The aim of this study was to evaluate the influence of constitutive and facultative skin pigmentation on low-fluence intense pulsed light (IPL)-induced adverse skin effects. STUDY DESIGN/MATERIALS AND METHODS: Twenty-one subjects with Fitzpatrick skin type II-IV were enrolled. Two buttock blocks...

  7. Studies on the protection effects of functional foods for skin immune system from radiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Yee, Sung Tae; Shin, Seong Hae; Kim, Do Sun; Heo, Ji Yun; Kang, Hye In [Sunchon National University, Sunchon (Korea, Republic of)

    2007-07-15

    We evaluated the protective effects of pilot products (HemoHIM and HemoTonic) on the UV-induced skin immune damages as the following. centre dot Protective effects of HemoHIM and HemoTonic against UV using contact hypersensitivity model - Protection against depression of contact hypersensitivity by administration and skin application of HemoHIM and HemoTonic - Induction of dendritic cell differentiation and maturation by HemoHIM and HemoTonic treatment - Improvement of antigen-presenting activity of dedritic cells by HemoHIM and HemoTonic treatment centre dot Protective effects of HemoHIM and HemoTonic on skin immune system against UV-irradiation - Protection of antigen-presenting activity of dendritic cells under UV-irradiation - In vivo protection of antigen-presenting activity of Langerhans cells in UV-irradiated mice centre dot Protective effects of HemoHIM on UV-induced apoptosis of dendritic cells - Inhibition of cell membrane change, mitochondrial potential change, SubG1 cell population, nuclear condensation, and DNA fragmentation in UV-irradiated dendritic cells centre dot Anti-allergic effects of HemoHIM and HemoTonic in human adipocyte HMC-1 cells - Inhibition of allergic histamine release from adipocytes - Inhibition of secretion of inflammatory cytokines (IL-6, IL-8, TNF-alpha, GM-CSF) - Inhibition of c-kit, tryptase, FcepsilonRI mRNA expression From these results, the developed functional food products (HemoHIM, HemoTonic) showed the protection and recovery of the immune functions in the UV-irradiated skin. It is suggested that these products may be used as a new functional food or cosmetic material for the protection of skin damage and the promotion of recovery

  8. Skin penetration and antioxidant effect of cosmeto-textiles with gallic acid.

    Science.gov (United States)

    Alonso, C; Martí, M; Barba, C; Lis, M; Rubio, L; Coderch, L

    2016-03-01

    In this work, the antioxidant gallic acid (GA) has been encapsulated in microspheres prepared with poly-ε-caprolactone (PCL) and incorporated into polyamide (PA) obtaining the cosmeto-textile. The topical application of the cosmeto-textile provides a reservoir effect in the skin delivery of GA. The close contact of the cosmeto-textile, containing microsphere-encapsulated GA (ME-GA), with the skin and their corresponding occlusion, may be the main reasons that explain the crossing of active principle (GA) through the skin barrier, located in the stratum corneum, and its penetration into the different compartments of the skin, epidermis and dermis. An ex vivo assessment was performed to evaluate the antioxidant effect of the ME-GA on the stratum corneum (SC) using the thiobarbituric acid-reactive species (TBARS) test. The test is based on a non-invasive ex vivo methodology that evaluates lipid peroxides formed in the outermost layers of the SC from human volunteers after UV radiation to determine the effectiveness of an antioxidant. In this case, a ME-GA cosmeto-textile or ME-GA formulation were applied to the skin in vivo and lipid peroxidation (LPO) in the horny layer were determined after UV irradiation. This methodology may be used as a quality control tool to determine ex vivo the percentage of LPO inhibition on human SC for a variety of antioxidants that are topically applied, in this case GA. Results show that LPO formation was inhibited in human SC when GA was applied directly or embedded in the cosmeto-textile, demonstrating the effectiveness of both applications. The percentage of LPO inhibition obtained after both topical applications was approximately 10% for the cosmeto-textile and 41% for the direct application of microspheres containing GA. This methodology could be used to determine the effectiveness of topically applied antioxidants encapsulated in cosmeto-textiles on human SC.

  9. Contrasting effects of ultraviolet-A and ultraviolet B exposure on induction of contact sensitivity in human skin

    DEFF Research Database (Denmark)

    Skov, Lone; Hansen, Henrik; Barker, J. N.

    1997-01-01

    Ultraviolet-B (UVB), in addition to direct effects on DNA, induces immunological changes in the skin that predispose to the development of skin cancer. Whether ultraviolet-A (UVA) induces similar changes is unknown. This effect can be investigated in humans in vivo using epicutaneous antigens...

  10. Effects of Vehicles and Enhancers on the Skin Permeation of Phytoestrogenic Diarylheptanoids from Curcuma comosa.

    Science.gov (United States)

    Tuntiyasawasdikul, Sarunya; Limpongsa, Ekapol; Jaipakdee, Napaphak; Sripanidkulchai, Bungorn

    2017-04-01

    Curcuma comosa (C. comosa) is widely used in traditional medicine as a dietary supplement for health promotion in postmenopausal women in Thailand. It contains several diarylheptanoids, which are considered to be a novel class of phytoestrogens. However, the diarylheptanoids isolated from the plant rhizome are shown to have low oral bioavailability and faster elimination characteristics. The aim of this study was to investigate the permeation behavior of the active compounds of diarylheptanoids. The effects of binary vehicle systems and permeation enhancers on diarylheptanoids permeation and accumulation within the skin were studied using side-by-side diffusion cells through the porcine ear skin. Among the tested binary vehicle systems, the ethanol/water vehicle appeared to be the most effective system for diarylheptanoids permeation with the highest flux and shortest lag time. The presence of transcutol in the vehicle system significantly increased diarylheptanoid's permeation and accumulation within the skin in a concentration-dependent manner. Although the presence of terpenes in formulation decreased the flux of diarylheptanoids, it raised the amount of diarylheptanoids retained within the skin substantially. Based on the feasibility of diarylheptanoid permeation, C. comosa extract should be further developed into an effective transdermal product for health benefits and hormone replacement therapy.

  11. Effect of Prayer and “OM” Meditation in Enhancing Galvanic Skin Response

    Directory of Open Access Journals (Sweden)

    Ira Das

    2012-10-01

    Full Text Available The research was conducted with the purpose to study the effect of prayer and meditation on galvanic skin response (GSR. It was hypothesized that there was a significant positive effect of prayer and meditation (Om chanting on galvanic skin response (GSR. The sample consisted of 20 normal, healthy female participants through purposive sampling. The age group of the sample was 18 to 24 years (Mean= 18.7, SD= 1.55. Gender was female and minimum education was graduation. The daily practice time of prayer and meditation session was 30 minutes for one month. Pre- Post data were recorded before and after intervention of prayer and meditation session by using single group pre-post research design. Recordings of galvanic skin response (GSR were made on a computerized polygraph (Model Physiopac, PP 4, Medicaid Systems, Chandigarh, India test. The results revealed a significant increase in GSR values as an effect of prayer and meditation which suggested the psychophysiological relaxation. Practicing prayer and meditation increases the galvanic skin response and hence decreases the stress level of the individual.

  12. Differential cytotoxic effects of graphene and graphene oxide on skin keratinocytes

    Science.gov (United States)

    Pelin, Marco; Fusco, Laura; León, Verónica; Martín, Cristina; Criado, Alejandro; Sosa, Silvio; Vázquez, Ester; Tubaro, Aurelia; Prato, Maurizio

    2017-01-01

    Impressive properties make graphene-based materials (GBMs) promising tools for nanoelectronics and biomedicine. However, safety concerns need to be cleared before mass production of GBMs starts. As skin, together with lungs, displays the highest exposure to GBMs, it is of fundamental importance to understand what happens when GBMs get in contact with skin cells. The present study was carried out on HaCaT keratinocytes, an in vitro model of skin toxicity, on which the effects of four GBMs were evaluated: a few layer graphene, prepared by ball-milling treatment (FLG), and three samples of graphene oxide (GOs, a research-grade GO1, and two commercial GOs, GO2 and GO3). Even though no significant effects were observed after 24 h, after 72 h the less oxidized compound (FLG) was the less cytotoxic, inducing mitochondrial and plasma-membrane damages with EC50s of 62.8 μg/mL (WST-8 assay) and 45.5 μg/mL (propidium iodide uptake), respectively. By contrast, the largest and most oxidized compound, GO3, was the most cytotoxic, inducing mitochondrial and plasma-membrane damages with EC50s of 5.4 and 2.9 μg/mL, respectively. These results suggest that only high concentrations and long exposure times to FLG and GOs could impair mitochondrial activity associated with plasma membrane damage, suggesting low cytotoxic effects at the skin level.

  13. Effect of chemical peeling on the skin in relation to UV irradiation.

    Science.gov (United States)

    Funasaka, Yoko; Abdel-Daim, Mohamed; Kawana, Seiji; Nishigori, Chikako

    2012-07-01

    Chemical peeling is one of the dermatological treatments available for certain cutaneous diseases and conditions or improvement of cosmetic appearance of photoaged skin. However, it needs to be clarified whether the repetitive procedure of chemical peeling on photodamaged skin is safe and whether the different chemicals used for peeling results in similar outcomes or not. In this article, we reviewed the effect of peeling or peeling agents on the skin in relation to ultraviolet (UV) radiation. The pretreatment of peeling agents usually enhance UV sensitivity by inducing increased sunburn cell formation, lowering minimum erythematous dose and increasing cyclobutane pyrimidine dimers. However, this sensitivity is reversible and recovers to normal after 1-week discontinuation. Using animals, the chronic effect of peeling and peeling agents was shown to prevent photocarcinogenesis. There is also an in vitro study using culture cells to know the detailed mechanisms of peeling agents, especially on cell proliferation and apoptotic changes via activating signalling cascades and oxidative stress. It is important to understand the effect of peeling agents on photoaged skin and to know how to deal with UV irradiation during the application of peeling agents and treatment of chemical peeling in daily life.

  14. Differential cytotoxic effects of graphene and graphene oxide on skin keratinocytes

    Science.gov (United States)

    Pelin, Marco; Fusco, Laura; León, Verónica; Martín, Cristina; Criado, Alejandro; Sosa, Silvio; Vázquez, Ester; Tubaro, Aurelia; Prato, Maurizio

    2017-01-01

    Impressive properties make graphene-based materials (GBMs) promising tools for nanoelectronics and biomedicine. However, safety concerns need to be cleared before mass production of GBMs starts. As skin, together with lungs, displays the highest exposure to GBMs, it is of fundamental importance to understand what happens when GBMs get in contact with skin cells. The present study was carried out on HaCaT keratinocytes, an in vitro model of skin toxicity, on which the effects of four GBMs were evaluated: a few layer graphene, prepared by ball-milling treatment (FLG), and three samples of graphene oxide (GOs, a research-grade GO1, and two commercial GOs, GO2 and GO3). Even though no significant effects were observed after 24 h, after 72 h the less oxidized compound (FLG) was the less cytotoxic, inducing mitochondrial and plasma-membrane damages with EC50s of 62.8 μg/mL (WST-8 assay) and 45.5 μg/mL (propidium iodide uptake), respectively. By contrast, the largest and most oxidized compound, GO3, was the most cytotoxic, inducing mitochondrial and plasma-membrane damages with EC50s of 5.4 and 2.9 μg/mL, respectively. These results suggest that only high concentrations and long exposure times to FLG and GOs could impair mitochondrial activity associated with plasma membrane damage, suggesting low cytotoxic effects at the skin level. PMID:28079192

  15. Effect of piracetam and nimodipine on full-thickness skin burns in rabbits.

    Science.gov (United States)

    Sari, Elif; Dincel, Gungor C

    2016-08-01

    The potential of several drugs for full-thickness skin burns has been investigated, but the treatment of such burns remains a challenge in plastic surgery. The present study was designed to determine the effect of systemic and topical administration of piracetam and nimodipine on full-thickness skin burn wound healing. A total of 36 New Zealand male rabbits were divided into six groups. Full-thickness skin burns were produced in all the groups, except the control group. Piracetam was administered systemically (piracetam-IV) and topically (piracetam-C) for 14 days, and nimodipine was administered systemically (nimodipine-IV) and topically (nimodipine-C) over the burn wounds for 14 days. The sham group underwent burn injury but was not administered any drug. After 21 days, gross examination and histopathological analysis were performed and the results were compared statistically. Nimodipine-C and nimodipine-IV had no effect on burn wound healing. However, both piracetam-IV and piracetam-C significantly enhanced the healing of the full-thickness skin burn wounds, although the latter was more effective, useful and practical in burn wound healing. The histopathological features of the wounds in the piracetam-C group were closer to those of the control group than those of the other groups. Piracetam-C rather than piracetam-IV may promote full-thickness burn wound healing in rabbits. © 2015 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

  16. Wall mass transfer and pressure gradient effects on turbulent skin friction

    Science.gov (United States)

    Watson, R. D.; Balasubramanian, R.

    1984-01-01

    The effects of mass injection and pressure gradients on the drag of surfaces were studied theoretically with the aid of boundary-layer and Navier-Stokes codes. The present investigation is concerned with the effects of spatially varying the injection in the case of flat-plate drag. Effects of suction and injection on wavy wall surfaces are also explored. Calculations were performed for 1.2 m long surfaces, one flat and the other sinusoidal with a wavelength of 30.5 cm. Attention is given to the study of the effect of various spatial blowing variations on flat-plate skin friction reduction, local skin friction coefficient calculated by finite difference boundary-layer code and Navier-Stokes code, and the effect of phase-shifting sinusoidal mass transfer on the drag of a sinusoidal surface.

  17. Measuring the effects of topically applied skin optical clearing agents and modeling the effects and consequences for laser therapies

    Science.gov (United States)

    Verkruysse, Wim; Khan, Misbah; Choi, Bernard; Svaasand, Lars O.; Nelson, J. Stuart

    2005-04-01

    Human skin prepared with an optical clearing agent manifests reduced scattering as a result of de-hydration and refractive index matching. This has potentially large effects for laser therapies of several skin lesions such as port wine stain, hair removal and tattoo removal. With most topically applied clearing agents the clearing effect is limited because they penetrate poorly through the intact superficial skin layer (stratum corneum). Agent application modi other than topical are impractical and have limited the success of optical clearing in laser dermatology. In recent reports, however, a mixture of lipofylic and hydrofylic agents was shown to successfully penetrate through the intact stratum corneum layer which has raised new interest in this field. Immediately after application, the optical clearing effect is superficial and, as the agent diffuses through the skin, reduced scattering is manifested in deeper skin layers. For practical purposes as well as to maximize therapeutic success, it is important to quantify the reduced scattering as well as the trans-cutaneous transport dynamics of the agent. We determined the time and tissue depth resolved effects of optically cleared skin by inserting a microscopic reflector array in the skin. Depth dependent light intensity was measured by quantifying the signal of the reflector array with optical coherence tomography. A 1-dimensional mass diffusion model was used to estimate a trans-cutaneous transport diffusion constant for the clearing agent mixture. The results are used in Monte Carlo modeling to determine the optimal time of laser treatment after topical application of the optical clearing agent.

  18. Nonlinear topographic effects in two-layer flows

    Directory of Open Access Journals (Sweden)

    Peter George Baines

    2016-02-01

    Full Text Available We consider the nature of non-linear flow of a two-layer fluid with a rigid lid over a long obstacle, such that the flow may be assumed to be hydrostatic. Such flows can generate hydraulic jumps upstream, and the model uses a new model of internal hydraulic jumps, which results in corrections to flows that have been computed using earlier models of jumps that are now known to be incorrect. The model covers the whole range of ratios of the densities of the two fluids, and is not restricted to the Boussinesq limit. The results are presented in terms of flow types in various regions of a Froude number-obstacle height (F0 – Hm diagram, in which the Froude number F0 is based on the initial flow conditions. When compared with single-layer flow, and some previous results with two layers, some surprising and novel patterns emerge on these diagrams. Specifically, in parts of the diagram where the flow may be supercritical (F0 > 1, there are regions where hysteresis may occur, implying that the flow may have two and sometimes three multiple flow states for the same conditions (i.e. values of F0 and Hm.

  19. Isotopic effects on non-linearity, molecular radius and intermolecular free length

    Indian Academy of Sciences (India)

    Ranjan Dey; Arvind K Singh; N K Soni; B S Bisht; J D Pandey

    2006-08-01

    Computation of non-linearity parameter (/), molecular radius (rm) and intermolecular free length (f) for H2O, C6H6, C6H12, CH3OH, C2H5OH and their deuterium-substituted compounds have been carried out at four different temperatures, viz., 293.15, 303.15, 313.15 and 323.15 K. The aim of the investigation is an attempt to study the isotopic effects on the non-linearity parameter and the physicochemical properties of the liquids, which in turn has been used to study their effect on the intermolecular interactions produced thereof.

  20. Nonlinear Random Effects Mixture Models: Maximum Likelihood Estimation via the EM Algorithm.

    Science.gov (United States)

    Wang, Xiaoning; Schumitzky, Alan; D'Argenio, David Z

    2007-08-15

    Nonlinear random effects models with finite mixture structures are used to identify polymorphism in pharmacokinetic/pharmacodynamic phenotypes. An EM algorithm for maximum likelihood estimation approach is developed and uses sampling-based methods to implement the expectation step, that results in an analytically tractable maximization step. A benefit of the approach is that no model linearization is performed and the estimation precision can be arbitrarily controlled by the sampling process. A detailed simulation study illustrates the feasibility of the estimation approach and evaluates its performance. Applications of the proposed nonlinear random effects mixture model approach to other population pharmacokinetic/pharmacodynamic problems will be of interest for future investigation.

  1. The effects of oppositely sloping boundaries with Ekman dissipation in a nonlinear baroclinic system

    Science.gov (United States)

    Weng, H.-Y.

    1990-01-01

    The present analytical and numerical examination of the effect of the slope Delta with dissipation delta on baroclinic flows in linear and nonlinear systems uses a modified Eady channel model with oppositely sloping top and bottom Ekman layers, and truncates the spectral wave solution up to six components. Comparisons are made wherever possible with results from beta-plane dissipative systems. In the linear system, the combined effect of Delta and delta strongly stabilizes long waves. In a nonlinear system without wave-wave interaction, Delta stabilizes the flow even for small delta and reduces the domain of vacillation while enlarging the domain of single-wave steady state.

  2. Aging skin.

    Science.gov (United States)

    Bolognia, J L

    1995-01-16

    Aging of the skin is a composite of actinic damage, chronologic aging, and hormonal influences. The majority of changes associated with aging, such as wrinkles and solar lentigines ("liver spots"), are due to photoaging and reflect cumulative sun exposure as well as skin pigmentation. Classically, chronologic aging includes those cutaneous changes that occur in non-sun-exposed areas, such as the buttocks, and are observed in both men and women. A clinical example would be soft tissue sagging due to elastic fiber degeneration. In women, investigations into the effect of hormones on aging of the skin have concentrated on estrogens; in men, there have been a limited number of studies on the influence of testosterone. The latter have shown an age-dependent decrease in tissue androgens in pubic skin, but not scrotal or thigh skin. To date, age has not been shown to have an effect on androgen receptor binding, although a decrease in foreskin 5 alpha-reductase activity with increasing age has been described. In fibroblast cultures from foreskins, there have been conflicting results as to whether 5 alpha-reductase activity decreases in an age-dependent manner. Some of the skin changes that have been categorized as secondary to chronologic aging, such as decreased sebaceous gland activity and decreased hair growth, may actually represent a decline in the concentration of tissue androgens with increasing age. The influence of androgens on age-related changes in keratinocyte and fibroblast function remains speculative.

  3. Hydrodynamic function of biomimetic shark skin: effect of denticle pattern and spacing.

    Science.gov (United States)

    Wen, Li; Weaver, James C; Thornycroft, Patrick J M; Lauder, George V

    2015-11-18

    The structure of shark skin has been the subject of numerous studies and recently biomimetic shark skin has been fabricated with rigid denticles (scales) on a flexible substrate. This artificial skin can bend and generate thrust when attached to a mechanical controller. The ability to control the manufacture of biomimetic shark skin facilitates manipulation of surface parameters and understanding the effects of changing denticle patterns on locomotion. In this paper we investigate the effect of changing the spacing and arrangement of denticles on the surface of biomimetic shark skin on both static and dynamic locomotor performance. We designed 3D-printed flexible membranes with different denticle patterns and spacings: (1) staggered-overlapped, (2) linear-overlapped, and (3) linear-non-overlapped, and compared these to a 3D-printed smooth-surfaced control. These 3D printed shark skin models were then tested in a flow tank with a mechanical flapping device that allowed us to either hold the models in a stationary position or move them dynamically. We swam the membranes at a frequency of 1 Hz with different heave amplitudes (from ±1 cm to ±3 cm) while measuring forces, torques, self-propelled swimming speed, and cost of transport (COT). Static tests revealed drag reduction of denticle patterns compared to a smooth control at low speeds, but increased drag at speeds above 25 cm s(-1). However, during dynamic (swimming) tests, the staggered-overlapped pattern produced the fastest swimming speeds with no significant increase in the COT at lower heave values. For instance, at a heave frequency of 1 Hz and amplitude of ±1 cm, swimming speed of the staggered-overlapped pattern increased by 25.2% over the smooth control. At higher heave amplitudes, significantly faster self-propelled swimming speeds were achieved by the staggered-overlapped pattern, but with higher COT. Only the staggered-overlapped pattern provides a significant swimming performance advantage over the

  4. Study of dispersive and nonlinear effects of coastal wave dynamics with a fully nonlinear potential flow model

    Science.gov (United States)

    Benoit, Michel; Yates, Marissa L.; Raoult, Cécile

    2017-04-01

    Efficient and accurate numerical models simulating wave propagation are required for a variety of engineering projects including the evaluation of coastal risks, the design of protective coastal structures, and the estimation of the potential for marine renewable energy devices. Nonlinear and dispersive effects are particularly significant in the coastal zone where waves interact with the bottom, the shoreline, and coastal structures. The main challenge in developing a numerical models is finding a compromise between computational efficiency and the required accuracy of the simulated wave field. Here, a potential approach is selected and the (fully nonlinear) water wave problem is formulated using the Euler-Zakharov equations (Zakharov, 1968) describing the temporal evolution of the free surface elevation and velocity potential. The proposed model (Yates and Benoit, 2015) uses a spectral approach in the vertical (i.e. the vertical variation of the potential is approximated by a linear combination of the first NT+1 Chebyshev polynomials, following the work of Tian and Sato (2008)). The Zakharov equations are integrated in time using a fourth-order Runge-Kutta scheme with a constant time step. At each sub-timestep, the Laplace Boundary Value Problem (BVP) is solved to estimate the free surface vertical velocity using the spectral approach, with typical values of NT between 5 to 8 for practical applications. The 1DH version of the code is validated with comparisons to the experimental data set of Becq-Girard et al. (1999), which studied the propagation of irregular waves over a beach profile with a submerged bar. The nonlinear and dispersive capacities of the model are verified with the correct representation of wave-wave interactions, in particular the transfer of energy between different harmonic components during wave propagation (analysis of the transformation of the variance spectrum along the channel). Evolution of wave skewness, asymmetry and kurtosis along the

  5. SOME POSSIBLE ULTRAVIOLET EFFECTS ON THE INCIDENCE OF SKIN CANCER AMONG JAPANESE DUE TO MODIFICATION OF THE OZONE LAYER

    OpenAIRE

    タキザワ, ユキオ; YUKIO, TAKIZAWA

    1987-01-01

    An epidemiological analysis was conducted in order to examine possible ultraviolet effects on the incidence of skin cancer among Japanese. Age-adjusted mortality rates (AMRs) and standardized mortality ratios (SMRs) from 1971 to 1977,ratios of cumulative mortality rates (CMRs) from 1950 to 1960 and from 1960 to 1970,and the number of patients from 1975 to 1980 were obtained for skin cancer and malignant melanoma from vital statistics of Japan. The results indicated that the AMRs of skin cance...

  6. Comparison of disposable diapers with fluff absorbent and fluff plus absorbent polymers: effects on skin hydration, skin pH, and diaper dermatitis.

    Science.gov (United States)

    Davis, J A; Leyden, J J; Grove, G L; Raynor, W J

    1989-06-01

    Diaper dermatitis results from the action of a number of physical and chemical factors on the skin. While its etiology is complex, there is agreement that prolonged contact between wet diapers and the skin leading to excessive hydration of the stratum corneum and reduced barrier function is a primary factor. Recent research also indicates that pH elevation resulting from ammonia production increases the probability of skin damage due to fecal enzyme activity. New diapers containing absorbent polymers blended with cellulose fluff in the absorbent core have been developed. The absorbent polymer binds fluids and controls pH in the diaper environment. To assess the effectiveness of these diapers, a clinical study was conducted with approximately 150 infants over 15 weeks, using fluff diapers and absorbent polymer diapers. The results clearly showed that the diapers with absorbent polymer provide a better skin environment than those with fluff only with respect to lower skin wetness and pH control (instrumental measurements). In addition, the clinicians' grades indicated a directional reduction in diaper rash severity.

  7. Nonlinear effects in the propagation of optically generated magnetostatic volume mode spin waves

    Science.gov (United States)

    van Tilburg, L. J. A.; Buijnsters, F. J.; Fasolino, A.; Rasing, T.; Katsnelson, M. I.

    2017-08-01

    Recent experimental work has demonstrated optical control of spin wave emission by tuning the shape of the optical pulse [Satoh et al., Nat. Photon. 6, 662 (2012), 10.1038/nphoton.2012.218]. We reproduce these results and extend the scope of the control by investigating nonlinear effects for large amplitude excitations. We observe an accumulation of spin wave power at the center of the initial excitation combined with short-wavelength spin waves. These kinds of nonlinear effects have not been observed in earlier work on nonlinearities of spin waves. Our observations pave the way for the manipulation of magnetic structures at a smaller scale than the beam focus, for instance in devices with all-optical control of magnetism.

  8. Nonlinear frequency conversion effect in a one-dimensional graphene-based photonic crystal

    Science.gov (United States)

    Wicharn, S.; Buranasiri, P.

    2015-07-01

    In this research, the nonlinear frequency conversion effect based on four-wave mixing (FWM) principle in a onedimensional graphene-based photonics crystal (1D-GPC) has been investigated numerically. The 1D-GPC structure is composed of two periodically alternating material layers, which are graphene-silicon dioxide bilayer system and silicon membrane. Since, the third-order nonlinear susceptibility χ(3) of bilayer system is hundred time higher than pure silicon dioxide layer, so the enhancement of FWM response can be achieved inside the structure with optimizing photon energy being much higher than a chemical potential level (μ) of graphene sheet. In addition, the conversion efficiencies of 1DGPC structure are compared with chalcogenide based photonic structure for showing that 1D-GPC structure can enhance nonlinear effect by a factor of 100 above the chalcogenide based structure with the same structure length.

  9. Beyond the effective mass approximation: predictive theory of the nonlinear optical response of conduction electrons

    CERN Document Server

    Yu, Shukai; Talbayev, Diyar

    2016-01-01

    We present an experimental and computational study of the nonlinear optical response of conduction electrons to intense terahertz (THz) electric field. Our observations (saturable absorption and an amplitude-dependent group refractive index) can be understood on the qualitative level as the breakdown of the effective mass approximation. However, a predictive theoretical description of the nonlinearity has been missing. We propose a model based on the semiclassical electron dynamics, a realistic band structure, and the free electron Drude parameters to accurately calculate the experimental observables in InSb. Our results open a path to predictive modeling of the conduction-electron optical nonlinearity in semiconductors, metamaterials, as well as high-field effects in THz plasmonics.

  10. Effects of ADC Nonlinearity on the Spurious Dynamic Range Performance of Compressed Sensing

    Directory of Open Access Journals (Sweden)

    Rongzong Kang

    2014-01-01

    Full Text Available Analog-to-information converter (AIC plays an important role in the compressed sensing system; it has the potential to significantly extend the capabilities of conventional analog-to-digital converter. This paper evaluates the impact of AIC nonlinearity on the dynamic performance in practical compressed sensing system, which included the nonlinearity introduced by quantization as well as the circuit non-ideality. It presents intuitive yet quantitative insights into the harmonics of quantization output of AIC, and the effect of other AIC nonlinearity on the spurious dynamic range (SFDR performance is also analyzed. The analysis and simulation results demonstrated that, compared with conventional ADC-based system, the measurement process decorrelates the input signal and the quantization error and alleviate the effect of other decorrelates of AIC, which results in a dramatic increase in spurious free dynamic range (SFDR.

  11. Effect of orally administered collagen hydrolysate on gene expression profiles in mouse skin: a DNA microarray analysis.

    Science.gov (United States)

    Oba, Chisato; Ito, Kyoko; Ichikawa, Satomi; Morifuji, Masashi; Nakai, Yuji; Ishijima, Tomoko; Abe, Keiko; Kawahata, Keiko

    2015-08-01

    Dietary collagen hydrolysate has been hypothesized to improve skin barrier function. To investigate the effect of long-term collagen hydrolysate administration on the skin, we evaluated stratum corneum water content and skin elasticity in intrinsically aged mice. Female hairless mice were fed a control diet or a collagen hydrolysate-containing diet for 12 wk. Stratum corneum water content and skin elasticity were gradually decreased in chronologically aged control mice. Intake of collagen hydrolysate significantly suppressed such changes. Moreover, we used DNA microarrays to analyze gene expression in the skin of mice that had been administered collagen hydrolysate. Twelve weeks after the start of collagen intake, no significant differences appeared in the gene expression profile compared with the control group. However, 1 wk after administration, 135 genes were upregulated and 448 genes were downregulated in the collagen group. This suggests that gene changes preceded changes of barrier function and elasticity. We focused on several genes correlated with functional changes in the skin. Gene Ontology terms related to epidermal cell development were significantly enriched in upregulated genes. These skin function-related genes had properties that facilitate epidermal production and differentiation while suppressing dermal degradation. In conclusion, our results suggest that altered gene expression at the early stages after collagen administration affects skin barrier function and mechanical properties. Long-term oral intake of collagen hydrolysate improves skin dysfunction by regulating genes related to production and maintenance of skin tissue.

  12. Characterization of atopic skin and the effect of a hyperforin-rich cream by laser scanning microscopy

    Science.gov (United States)

    Meinke, Martina C.; Richter, Heike; Kleemann, Anke; Lademann, Juergen; Tscherch, Kathrin; Rohn, Sascha; Schempp, Christoph M.

    2015-05-01

    Atopic dermatitis (AD) is a multifactorial inflammatory skin disease that affects both children and adults in an increasing manner. The treatment of AD often reduces subjective skin parameters, such as itching, dryness, and tension, but the inflammation cannot be cured. Laser scanning microscopy was used to investigate the skin surface, epidermal, and dermal characteristics of dry and atopic skin before and after treatment with an ointment rich in hyperforin, which is known for its anti-inflammatory effects. The results were compared to subjective parameters and transepidermal water loss, stratum corneum moisture, and stratum corneum lipids. Using biophysical methods, in particular laser scanning microscopy, it was found that atopic skin has distinct features compared to healthy skin. Treatment with a hyperforin-rich ointment resulted in an improvement of the stratum corneum moisture, skin surface dryness, skin lipids, and the subjective skin parameters, indicating that the barrier is stabilized and improved by the ointment. But in contrast to the improved skin surface, the inflammation in the deeper epidermis/dermis often continues to exist. This could be clearly shown by the reflectance confocal microscopy (RCM) measurements. Therefore, RCM measurements could be used to investigate the progress in treatment of atopic dermatitis.

  13. Effective supercontinuum generation by using highly nonlinear dispersion-shifted fiber incorporated with Si nanocrystals.

    Science.gov (United States)

    Jeong, Seongmook; Ju, Seongmin; Kim, Youngwoong; Watekar, Pramod R; Jeong, Hyejeong; Lee, Ho-Jae; Boo, Seongjae; Kim, Dug Young; Han, Won-Taek

    2012-01-01

    The dispersion-shifted fiber (DSF) incorporated with Si nanocrystals (Si-NCs) having highly nonlinear optical property was fabricated to investigate the effective supercontinuum generation characteristics by using the MCVD process and the drawing process. Optical nonlinearity was enhanced by incorporating Si nanocrystals in the core of the fiber and the refractive index profile of a dispersion-shifted fiber was employed to match its zero-dispersion wavelength to that of the commercially available pumping source for generating effective supercontinuum. The non-resonant nonlinear refractive index, n2, of the Si-NCs doped DSF measured by the cw-SPM method was measured to be 7.03 x 10(-20) [m2/W] and the coefficient of non-resonant nonlinearity, gamma, was 7.14 [W(-1) km(-1)]. To examine supercontinuum generation of the Si-NCs doped DSF, the femtosecond fiber laser with the pulse width of 150 fs (at 1560 nm) was launched into the fiber core. The output spectrum of the Si-NCs doped DSF was found to broaden from 1300 nm to wavelength well beyond 1700 nm, which can be attributed to the enhanced optical nonlinearity by Si-NCs embedded in the fiber core. The short wavelength of the supercontinuum spectrum in the Si-NCs doped DSF showed shift from 1352 nm to 1220 nm for the fiber length of 2.5 m and 200 m, respectively.

  14. THEORETICAL EVALUATION OF NONLINEAR EFFECTS ON OPTICAL WDM NETWORKS WITH VARIOUS FIBER TYPES

    Directory of Open Access Journals (Sweden)

    YASIN M. KARFAA

    2010-09-01

    Full Text Available A theoretical study is carried out to evaluate the performance of an opticalwavelength division multiplexing (WDM network transmission system in the presenceof crosstalk due to optical fiber nonlinearities. The most significant nonlinear effects inthe optical fiber which are Cross-Phase Modulation (XPM, Four-Wave Mixing (FWM,and Stimulated Raman Scattering (SRS are investigated. Four types of optical fiber areincluded in the analysis; these are: single-mode fiber (SMF, dispersion compensationfiber (DCF, non-zero dispersion fiber (NZDF, and non-zero dispersion shifted fiber(NZDSF. The results represent the standard deviation of nonlinearity induced crosstalknoise power due to FWM and SRS, XPM power penalty for SMF, DCF, NZDF, andNZDSF types of fiber, besides the Bit Error Rate (BER for the three nonlinear effectsusing standard fiber type (SMF. It is concluded that three significant fiber nonlinearitiesare making huge limitations against increasing the launched power which is desired,otherwise, lower values of launched power limit network expansion including length,distance, covered areas, and number of users accessing the WDM network, unlesssuitable precautions are taken to neutralize the nonlinear effects. Besides, various fibertypes are not behaving similarly towards network parameters.

  15. Modeling the Substrate Skin Effects in Mutual RL Characteristics.,

    Directory of Open Access Journals (Sweden)

    D. de Roest

    2003-12-01

    Full Text Available The goal of this work was to model the influence of the substrateskin effects on the distributed mutual impedance per unit lengthparameters of multiple coupled on-chip interconnects. The proposedanalytic model is based on the frequency-dependent distribution of thecurrent in the silicon substrate and the closed form integrationapproach. It is shown that the calculated frequency-dependentdistributed mutual inductance and the associated mutual resistance arein good agreement with the results obtained from CAD-oriented circuitmodeling technique.

  16. The Effects of Advertising Strategies on Consumer Trust: A Case of Skin Care Products in Taiwan

    Directory of Open Access Journals (Sweden)

    Velly Anatasia

    2016-09-01

    Full Text Available The main aim of this study was to develop advertising strategies in order to increase consumer trust. Four advertising elements, celebrity endorsement, branding, product attribute, and third party certification, were investigated in this study. Data were collected to answer two research questions: (1 To investigate the advertising strategies of skin care products leading to consumer trust, (2 To know the effects of advertising strategies in skin care products on consumer trust. A 5-point Likert scale survey was distributed to the female population in Taipei area. Via online and personal approaches, 266 questionnaires were returned. Targeting on 18-30 years old female skin care product users who stay in Taipei area more than six months, 240 qualified questionnaires were analyzed. The four independent variables are found having a significant relationship with trust in skin care advertising, in which branding has the greatest influence on increasing consumer trust. The control variable which is financial status is not found having statistically significant effect on consumer trust. To conclude, this study is dedicated to the communities in order to optimize their marketing strategies.

  17. Radioprotective effects of dimethyl sulfoxide in the artificial skin reconstructed with cultured human cells

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Young Ha; Choi, Karp Shik [College of Dentistry, Kyungpook National University, Daegu (Korea, Republic of); Song, In Hwan [Department of Anatomy, College of Medicine, Yeungnam University, Daegu (Korea, Republic of)

    2002-03-15

    To evaluate cultured human artificial skin as an experimental model for studying radiation effects in vitro. The skin was constructed by culturing keratinocytes over collagen lattice which made by culturing fibroblasts. Two groups were irradiated to gamma rays at single dose of 25 Gy with or without 3.5% of DMSO. Ultrastructures were investigated by electron microscopy after irradiation. The number of epidermal layers and expression of cytokeratin (CK) 14 and 10 were also seem by light microscopy. At 2 days after irradiation in experimental group without DMSO, necrotic cells were rarely found in the spinosal layer and undercornified cells were visible in the horney layer. Similar findings were also found in experimental group with DMSO but in mild form. The number of epidermal layers in experimental group without DMSO were significantly fewer than other group. CK 14 expressed in all the layer excluding horney layer but CK 10 expressed over 3-4 basal layers. Such patterns of CK expression were similar to all groups. It is suggested that structures of the keratinocytes and epidermal formation could be disturbed by irradiation in artificial skin and that DMSO can protect these damages. Therefore this work could be used as an organotypic experimental model in vitro using human cells for studying radiation effect in skin. Furthermore structural findings provided in this study could be used as useful basic data in further study using this model.

  18. Effect of different pretreatments on functional properties of African catfish (Clarias gariepinus) skin gelatin.

    Science.gov (United States)

    See, S F; Ghassem, M; Mamot, S; Babji, A S

    2015-02-01

    Pretreatments with different types of alkali and acid were compared to determine their effects on gelatin extraction from African catfish (Clarias gariepinus) skin. The study was divided into three parts. In the first part, the skins were only treated with alkaline (Ca(OH)2 or NaOH) solution or pretreated with acetic acid solution. For second part, combination of alkali and acid pretreatment was carried out. For the third part, the skins were first treated with NaOH solution, followed by the treatment with acetic acid, citric acid or sulfuric acid solution. Functional properties including the yield of protein recovery, gel strength, viscosity, pH and viscoelastic properties were determined on gelatins obtained with different pretreatment conditions. Pretreatment with alkali removed noncollagenous proteins effectively, whilst acid pretreatment induced some loss of collagenous proteins. Combination of alkali and acid pretreatment not only removed the noncollagenous proteins and caused a significant amount of swelling, but also provided the proper pH condition for extraction, during which some cross-linkages could be further destroyed but with less breakage of intramolecular peptide chains. Pretreatment of catfish skins with 0.2 N NaOH followed by 0.05 M acetic acid improved yield of protein recovery, gel strength, viscosity, melting temperature and gelling temperature of gelatin extract.

  19. Silica-glass contribution to the effective nonlinearity of hollow-core photonic band-gap fibers.

    Science.gov (United States)

    Hensley, Christopher J; Ouzounov, Dimitre G; Gaeta, Alexander L; Venkataraman, Natesan; Gallagher, Michael T; Koch, Karl W

    2007-03-19

    We measure the effective nonlinearity of various hollow-core photonic band-gap fibers. Our findings indicate that differences of tens of nanometers in the fiber structure result in significant changes to the power propagating in the silica glass and thus in the effective nonlinearity of the fiber. These results show that it is possible to engineer the nonlinear response of these fibers via small changes to the glass structure.

  20. Nonlinear effects in the torsional adjustment of interacting DNA.

    Science.gov (United States)

    Kornyshev, A A; Wynveen, A

    2004-04-01

    DNA molecules in solution, having negatively charged phosphates and countercations readsorbed on its surface, possess a distinct charge separation motif to interact electrostatically. If their double-helical structure were ideal, duplexes in parallel juxtaposition could choose azimuthal alignment providing attraction, or at least a reduction of repulsion, between them. But duplexes are not perfect staircases and the distortions of their helical structure correlate with their base pair texts. If the patterns of distortions on the opposing molecules are uncorrelated, the mismatch will accumulate as a random walk and attraction vanishes. Based on this idea, a model of recognition of homologous sequences has been proposed [A. A. Kornyshev and S. Leikin, Phys. Rev. Lett. 86, 3666 (2001)]. But DNA has torsional elasticity. How will this help to relax a mismatch between the charge distributions on two nonhomologous DNA's? In the same work, the solution of this problem has been mapped onto a frustrated sine Gordon equation in a nonlocal random field (where the latter represents a pattern of twist angle distortions on the opposing molecules), but the results had been obtained in the limit of torsionally rigid molecules. In the present paper, by solving this equation numerically, we find a strongly nonlinear relaxation mechanism which utilizes static kink-soliton modes triggered by the "random field." In the range of parameters where the solitons do not emerge, we find good agreement with the results of a variational study [A. G. Cherstvy, A. A. Kornyshev, and S. Leikin, J. Phys. Chem. B (to be published)]. We reproduce the first-order transitions in the interaxial separation dependence, but detect also second-order or weak first-order transitions for shorter duplexes. The recognition energy between two nonhomologous DNA sequences is calculated as a function of interaxial separation and the length of juxtaposition. The soliton-caused kinky length dependence is discussed in

  1. Nonlinear effects in the torsional adjustment of interacting DNA

    Science.gov (United States)

    Kornyshev, A. A.; Wynveen, A.

    2004-04-01

    DNA molecules in solution, having negatively charged phosphates and countercations readsorbed on its surface, possess a distinct charge separation motif to interact electrostatically. If their double-helical structure were ideal, duplexes in parallel juxtaposition could choose azimuthal alignment providing attraction, or at least a reduction of repulsion, between them. But duplexes are not perfect staircases and the distortions of their helical structure correlate with their base pair texts. If the patterns of distortions on the opposing molecules are uncorrelated, the mismatch will accumulate as a random walk and attraction vanishes. Based on this idea, a model of recognition of homologous sequences has been proposed [A. A. Kornyshev and S. Leikin, Phys. Rev. Lett. 86, 3666 (2001)]. But DNA has torsional elasticity. How will this help to relax a mismatch between the charge distributions on two nonhomologous DNA’s? In the same work, the solution of this problem has been mapped onto a frustrated sine Gordon equation in a nonlocal random field (where the latter represents a pattern of twist angle distortions on the opposing molecules), but the results had been obtained in the limit of torsionally rigid molecules. In the present paper, by solving this equation numerically, we find a strongly nonlinear relaxation mechanism which utilizes static kink-soliton modes triggered by the “random field.” In the range of parameters where the solitons do not emerge, we find good agreement with the results of a variational study [A. G. Cherstvy, A. A. Kornyshev, and S. Leikin, J. Phys. Chem. B (to be published)]. We reproduce the first-order transitions in the interaxial separation dependence, but detect also second-order or weak first-order transitions for shorter duplexes. The recognition energy between two nonhomologous DNA sequences is calculated as a function of interaxial separation and the length of juxtaposition. The soliton-caused kinky length dependence is

  2. The effects of sodium oxybate on core body and skin temperature regulation in narcolepsy.

    Science.gov (United States)

    van der Heide, Astrid; Donjacour, Claire E H M; Pijl, Hanno; Reijntjes, Robert H A M; Overeem, Sebastiaan; Lammers, Gert J; Van Someren, Eus J W; Fronczek, Rolf

    2015-10-01

    Patients suffering from narcolepsy type 1 show altered skin temperatures, resembling the profile that is related to sleep onset in healthy controls. The aim of the present study is to investigate the effects of sodium oxybate, a widely used drug to treat narcolepsy, on the 24-h profiles of temperature and sleep-wakefulness in patients with narcolepsy and controls. Eight hypocretin-deficient male narcolepsy type 1 patients and eight healthy matched controls underwent temperature measurement of core body and proximal and distal skin twice, and the sleep-wake state for 24 h. After the baseline assessment, 2 × 3 g of sodium oxybate was administered for 5 nights, immediately followed by the second assessment. At baseline, daytime core body temperature and proximal skin temperature were significantly lower in patients with narcolepsy (core: 36.8 ± 0.05 °C versus 37.0 ± 0.05 °C, F = 8.31, P = 0.01; proximal: 33.4 ± 0.26 °C versus 34.3 ± 0.26 °C, F = 5.66, P = 0.03). In patients, sodium oxybate administration increased proximal skin temperature during the day (F = 6.46, P = 0.04) to a level similar as in controls, but did not affect core body temperature, distal temperature or distal-proximal temperature gradient. Sodium oxybate administration normalised the predictive value of distal skin temperature and distal-proximal temperature gradient for the onset of daytime naps (P < 0.01). In conclusion, sodium oxybate administration resulted in a partial normalisation of the skin temperature profile, by increasing daytime proximal skin temperature, and by strengthening the known relationship between skin temperature and daytime sleep propensity. These changes seem to be related to the clinical improvement induced by sodium oxybate treatment. A causal relationship is not proven.

  3. Modeling skin effect in large magnetized iron detectors

    CERN Document Server

    Incurvati, M

    2003-01-01

    The experimental problem of the calibration of magnetic field in large iron detectors is discussed. Emphasis is laid on techniques based on ballistic measurements as the ones employed by MINOS or OPERA.In particular, we provide analytical formulas to model the behavior of the apparatus in the transient regime, keeping into account eddy current effects and the finite penetration velocity of the driving fields. These formulas ease substantially the design of the calibration apparatus.Results are compared with experimental data coming from a prototype of the OPERA spectrometer.

  4. [Effect of topical application of aminoguanidine cream on skin tissue of rats with diabetes].

    Science.gov (United States)

    Tian, Ming; Qing, Chun; Cao, Xiao-Zan; Niu, Yi-Wen; Lu, Shu-Liang

    2011-02-01

    To investigate the effects of aminoguanidine cream on the proliferation of keratinocytes (KC), content of advanced glycosylation end products (AGE) and oxidative stress in skin tissue of rats with diabetes. Stearic acid, liquid paraffin, vaseline, lanolin, isopropyl myristate fat, glycerol, 50 g/L alcohol paraben, aminoguanidine hydrochloride etc. were mixed in certain proportion to make aminoguanidine cream, and cream without aminoguanidine was used as matrix. The dorsal skin of normal rats were harvested and treated by aminoguanidine cream with dose of 5, 10 g/L, or 5 g/L together with 10 g/L azone. The transdermal effect was respectively measured at post treatment hour 2, 4, 7, 10, 12, 24. Thirty SD rats were divided into normal control (NC, n = 6), diabetes (D, n = 8), aminoguanidine cream-interfered (AI, n = 8), matrix cream-interfered groups (MI, n = 8) according to the random number table. Diabetes was reproduced by intraperitoneal injection of STZ (65 mg/kg) in rats of D, AI, and MI groups, and rats in NC group were injected with 0.05 mmol/L citrate buffer as control. One week later, dorsal skin of rats in AI and MI groups were respectively treated with 10 g/L aminoguanidine cream and matrix cream by external use for 4 weeks. AGE content was determined with fluorescence detection from skin collagen extract. KC cell cycle was detected by flow cytometry. Skin tissue specimens were obtained for determination of levels of superoxide dismutase (SOD), malondialdehyde (MDA), myeloperoxidase (MPO), and total antioxidant capacity. Data were processed with t test. Transdermal effect of aminoguanidine cream with dose of 10 g/L was better than that with 5 g/L or 5 g/L + 10 g/L azone cream. One rat was not induced successfully in MI group. Four weeks after model reproduction, 4 rats died in D group and 1 rat died in AI group. The AGE content in D group was obviously higher than that in NC group [(36.8 +/- 2.6), (24.6 +/- 2.7) U per milligram hydroxyproline, respectively

  5. Collisional effects in weakly collisional plasmas: nonlinear electrostatic waves and recurrence phenomena

    Science.gov (United States)

    Camporeale, E.; Pezzi, O.; Valentini, F.

    2015-12-01

    The longstanding problem of collisions in plasmas is a very fascinating and huge topic in plasma physics. The 'natural' operator that describes the Coulombian interactions between charged particles is the Landau (LAN) integral operator. The LAN operator is a nonlinear, integro-differential and Fokker-Planck type operator which satisfies the H theorem for the entropy growth. Due to its nonlinear nature and multi-dimensionality, any approach to the solution of the Landau integral is almost prohibitive. Therefore collisions are usually modeled by simplified collisional operators. Here collisional effects are modeled by i) the one-dimensional Lenard-Bernstein (LB) operator and ii) the three-dimensional Dougherty (DG) operator. In the first case i), by focusing on a 1D-1V phase space, we study recurrence effects in a weakly collisional plasma, being collisions modeled by the LB operator. By decomposing the linear Vlasov-Poisson system in the Fourier-Hermite space, the recurrence problem is investigated in the linear regime of the damping of a Langmuir wave and of the onset of the bump-on-tail instability. The analysis is then confirmed and extended to the nonlinear regime through a Eulerian collisional Vlasov-Poisson code. Despite being routinely used, an artificial collisionality is not in general a viable way of preventing recurrence in numerical simulations. Moreover, recursive phenomena affect both the linear exponential growth and the nonlinear saturation of a linear instability by producing a fake growth in the electric field, thus showing that, although the filamentation is usually associated with low amplitude fluctuations contexts, it can occur also in nonlinear phenomena. On the other hand ii), the effects of electron-electron collisions on the propagation of nonlinear electrostatic waves are shown by means of Eulerian simulations in a 1D-3V (one dimension in physical space, three dimensions in velocity space) phase space. The nonlinear regime of the symmetric

  6. Synergistic effects of green tea and ginkgo biloba extracts on the improvement of skin barrier function and elasticity.

    Science.gov (United States)

    Campos, Patricia M B G Maia; Gianeti, Mirela D; Mercurio, Daiane G; Gaspar, Lorena R

    2014-09-01

    This study aimed to evaluate the effects of cosmetic formulations containing green tea (GT) and/or Ginkgo biloba (GB) extracts by preclinical and clinical studies. For the preclinical study, histological analysis was performed after 5 day-period of formulations application on the dorsum of hairless mice. For the clinical study, the formulations were applied on the forearm skin of 48 volunteers, and assessed before and after 3 hours and after a 15 and 30 day-period of application. Histological analysis showed that the formulation with GT (FGT) and the association of GT and GB (FBlend) significantly enhanced viable epidermis thickness and the number of cell layers, suggesting a moisturizing effect in skin deeper layers and increased cell renewal. The clinical efficacy studies showed that the extracts had a moisturizing effect and improved skin microrelief. In addition they synergistically acted on the skin elasticity and skin barrier function. In conclusion, the formulation containing a combination of green tea and Ginkgo biloba extracts effectively improved skin conditions and the effect of formulation FBlend on the improvement of skin elasticity was more pronounced. Finally, the results of the present study revealed other important clinical benefits of Ginkgo biloba and green tea extracts on the skin besides their already known antioxidant action.

  7. Effects of Nicotinamide on Mouse Skin Tumor Development and lts Mode of Action

    Institute of Scientific and Technical Information of China (English)

    KRISHNA P. GUPTA

    1999-01-01

    Nicotinamide (NA), a naturally occuring vitamin and a protease inhibitor, has been shown to be effective in treating some skin ailments. It inhibits cell proliferation and induces cell differentiation. This report shows the effects of NA on mouse skin tumor development and on the critical events involved in this process. NA reduced tumor growth, inhibited the 12-O-tetradecanoylphorbol- 13-acetate (TPA) induced ornithine decarboxylase activity, but induced the transglutaminase activity which was inhibited by TPA under different experimental conditions.The effects of NA on ornithine decarboxylase (ODC) and transglutaminase (TG) indicated that nicotinamide (NA) probably programmmed the cells for their death in the natural course of time, I.e. Programed cell death. This observation indicates that NA might be a better agent for the detailed study and for the better use in prevention of cancer alone or in combination with other drugs.

  8. Temperature correction to the Casimir force in cryogenic range and anomalous skin effect

    CERN Document Server

    Svetovoy, V B

    2003-01-01

    Temperature correction to the Casimir force is considered for real metals at low temperatures. With the temperature decrease the mean free path for electrons becomes larger than the field penetration depth. In this condition description of metals with the impedance of anomalous skin effect is shown to be more appropriate than with the permittivity. The effect is crucial for the temperature correction. It is demonstrated that in the zero frequency limit the reflection coefficients should coincide with those of ideal metal if we demand the entropy to be zero at T=0. All the other prescriptions discussed in the literature for the $n=0$ term in the Lifshitz formula give negative entropy. It is shown that the temperature correction in the region of anomalous skin effect is not suppressed as it happens in the plasma model. This correction will be important in the future cryogenic measurements of the Casimir force.

  9. Effects of nonlinear strength parameters on stability of 3D soil slopes

    Institute of Scientific and Technical Information of China (English)

    高玉峰; 吴迪; 张飞; 秦红玉; 朱德胜

    2016-01-01

    Actual slope stability problems have three-dimensional (3D) characteristics and the soils of slopes have curved failure envelopes. This incorporates a power-law nonlinear failure criterion into the kinematic approach of limit analysis to conduct the evaluation of the stability of 3D slopes. A tangential technique is adopted to simplify the nonlinear failure criterion in the form of equivalent Mohr-Coulomb strength parameters. A class of 3D admissible rotational failure mechanisms is selected for soil slopes including three types of failure mechanisms: face failure, base failure, and toe failure. The upper-bound solutions and corresponding critical slip surfaces can be obtained by an efficient optimization method. The results indicate that the nonlinear parameters have significant influences on the assessment of slope stability, especially on the type of failure mechanism. The effects of nonlinear parameters appear to be pronounced for gentle slopes constrained to a narrow width. Compared with the solutions derived from plane-strain analysis, the 3D solutions are more sensitive to the values of nonlinear parameters.

  10. Nonlinear effects manifested in infrasonic signals in the region of a geometric shadow

    Science.gov (United States)

    Kulichkov, S. N.; Golikova, E. V.

    2013-01-01

    Nonlinear effects manifested in infrasonic signals passing through different atmospheric heights and recorded in the region of a geometric shadow have been studied. The source of infrasound was a surface explosion equivalent to 20-70 t of TNT. The frequencies of the spectral maxima of infrasonic signals, which correspond to the reflections of acoustic pulses from atmospheric inhomogeneities at different heights within the stratosphere-mesosphere-lower thermosphere layer, were calculated using the nonlinear-theory method. A satisfactory agreement between experimental and calculated data was obtained.

  11. Solution of Excited Non-Linear Oscillators under Damping Effects Using the Modified Differential Transform Method

    Directory of Open Access Journals (Sweden)

    H. M. Abdelhafez

    2016-03-01

    Full Text Available The modified differential transform method (MDTM, Laplace transform and Padé approximants are used to investigate a semi-analytic form of solutions of nonlinear oscillators in a large time domain. Forced Duffing and forced van der Pol oscillators under damping effect are studied to investigate semi-analytic forms of solutions. Moreover, solutions of the suggested nonlinear oscillators are obtained using the fourth-order Runge-Kutta numerical solution method. A comparison of the result by the numerical Runge-Kutta fourth-order accuracy method is compared with the result by the MDTM and plotted in a long time domain.

  12. Effect of loss on photon-pair generation in nonlinear waveguides arrays

    CERN Document Server

    Antonosyan, Diana A; Sukhorukov, Andrey A

    2014-01-01

    We describe theoretically the process of spontaneous parametric down-conversion in quadratic nonlinear waveguide arrays in the presence of linear loss. We derive a set of discrete Schrodinger-type equations for the biphoton wave function, and the wave function of one photon when the other photon in a pair is lost. We demonstrate effects arising from loss-affected interference between the generated photon pairs and show that nonlinear waveguide arrays can serve as a robust loss-tolerant integrated platform for the generation of entangled photon states with non-classical spatial correlations.

  13. Nonlinear Effect on Focusing Gain of a Focusing Transducer with a Wide Aperture Angle

    Institute of Scientific and Technical Information of China (English)

    LIU Ming-He; ZHANG Dong; GONG Xiu-Fen

    2007-01-01

    @@ Nonlinear effect on focusing gain of acoustic field radiated from a 1-MHz focusing transmitter with a wide aperture angle of 35° is theoretically and experimentally investigated. With the enhancement of nonlinearity, the focusing gains of both intensity and peak positive pressure show non-monotonic behaviour. There exist the same saturated levels at which the maximum outputs are reached and their spatial distributions are more localized. In contrast,the peak negative pressure always decreases monotonically and its spatial distribution is less localized.

  14. Therapeutic Effects of Erythroid Differentiation Regulator 1 on Imiquimod-Induced Psoriasis-Like Skin Inflammation

    Directory of Open Access Journals (Sweden)

    Kyung Eun Kim

    2016-02-01

    Full Text Available Psoriasis is a common skin disease accompanied by chronic inflammation. In previous studies, erythroid differentiation regulator 1 (ERDR1 was shown to have a negative correlation with proinflammatory cytokine IL-18. However, the role of ERDR1 in the inflammatory skin disease psoriasis has not been evaluated. In this study, to investigate the role of ERDR1 in psoriasis, recombinant ERDR1 was injected intraperitoneally into a psoriasis mouse model. Recombinant ERDR1 (rERDR1 significantly alleviated the symptoms of psoriasis-like skin inflammation and reduced the mRNA of various psoriasis-related markers, including keratin 14, S100A8, and Th17-related cytokines IL-17 and IL-22, suggesting that rERDR1 exerts therapeutic effects on psoriasis via the regulation of Th17 functions. Additionally, the expression of CCL20, a well-known Th17 attracting chemokine, was determined. CCL20 expression significantly decreased in the rERDR1-injected group compared with the vehicle (PBS-injected group. CCR6 expression in the psoriatic lesional skin was also decreased by rERDR1 administration, implying the inhibition of CCR6-expressing Th17 cell chemotaxis via the downregulation of CCL20. Taken together, this study provides the first evidence that ERDR1 may be a potential therapeutic target for psoriasis.

  15. Effect of skin disinfection with octenidine dihydrochloride on insertion site colonization of intravascular catheters.

    Science.gov (United States)

    Dettenkofer, M; Jonas, D; Wiechmann, C; Rossner, R; Frank, U; Zentner, J; Daschner, F D

    2002-10-01

    We investigated the efficacy of two commercially available, alcohol-based antiseptic solutions in decontaminating the insertion site of central lines. One solution contained the bispyridine octenidine dihydrochloride. Inpatients receiving either a central venous catheter (CVC) or a peripherally inserted central catheter (PICC) were alternately assigned to different skin disinfection regimens at the insertion site: (A) 0.1% octendine dihydrochloride with 30% 1-propanol and 45% 2-propanol, (B) 74% ethanol with 10% 2-propanol. Quantitative skin cultures were obtained from the insertion site at predetermined intervals. A total of 60 patients received 12 CVCs and 47 PICCs (no significant difference with respect to gender, age and catheter type). In total, 90 cultures were assessed in each group. The median colony-forming unit (cfu) counts per 24 cm(2) (group A vs B) were 2,270 vs 2,950 before, 20 vs 40 following and 860 vs 1,210 24 h after catheter insertion, respectively. A statistically significant difference in the efficacy of skin decontamination was seen between groups in culture set (3) and in the difference between culture sets (2) and (3) (Wilcoxon rank sum test). Octenidine/propanol appears to be more effective than alcohol (ethanol/propanol) alone in reducing microflora of the skin at the PICC/CVC insertion site over a 24-h period.

  16. Effect of Red Clover Isoflavones over Skin, Appendages, and Mucosal Status in Postmenopausal Women

    Directory of Open Access Journals (Sweden)

    Markus Lipovac

    2011-01-01

    Full Text Available Objective. Evaluate in postmenopausal women the effect of red clover extract (RCE isoflavones over subjective status of skin, appendages, and several mucosal sites. Method. Postmenopausal women (n=109 were randomly assigned to receive either two daily capsules of the active compound (80 mg RCE, Group A or placebo of equal appearance (Group B for a 90-day period. After a washout period of 7 days, medication was crossed over and taken for 90 days more. Subjective improvement of skin, appendages, and several mucosal site status was assessed for each studied group at 90 and 187 days using a visual analogue scale (VAS. In addition, libido, tiredness, and urinary, sleep, and mood complaints were also evaluated. Results. Women after RCE intervention (both groups reported better subjective improvement of scalp hair and skin status, libido, mood, sleep, and tiredness. Improvement of urinary complaints, nail, body hair, and mucosa (oral, nasal, and ocular status did not differ between treatment phases (intra- and intergroup. Overall satisfaction with treatment was reported higher after RCE intervention (both groups as compared to placebo. Conclusion. RCE supplementation exerted a subject improvement of scalp hair and skin status as well as libido, mood, sleep, and tiredness in postmenopausal women.

  17. Effect of Localized Mechanical Indentation on Skin Water Content Evaluated Using OCT

    Directory of Open Access Journals (Sweden)

    Abhijit A. Gurjarpadhye

    2011-01-01

    Full Text Available 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 in ex vivo porcine skin, as well as changes in signal intensity profile when imaging in vivo human skin. Compression of ex vivo porcine 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 vivo OCT 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.

  18. Effectiveness of body wipes as an adjunct to reducing skin infections in high school wrestlers.

    Science.gov (United States)

    Anderson, B J

    2012-09-01

    To compare soap-and-water body wipes and 70% isopropyl alcohol (IPA) body wipes to a CONTROL (no treatment) in reducing skin infections in high school wrestlers competing in weekend tournaments. Repeated measures study evaluating a soap-and-water body wipe, a 70% IPA body wipe, and no-treatment CONTROL during 2 weekend tournaments. High school wrestling tournaments in Minneapolis-St Paul and surrounding communities of Minnesota. Each team was randomly assigned to use either wipe or serve as CONTROL during each tournament. Presence of skin infections that developed the following week after a weekend tournament. A total of 151 athletes competed in a total of 474 individual matches. Thirteen athletes tested positive afterward for skin infections. The odds of infection for the tested group compared with the CONTROL group were 0.089 [95% confidence interval (CI), 0.01-0.75; P = 0.026] for the soap-and-water group and 0.44 (95% CI, 0.11-1.69; P = 0.23) for 70% IPA group. Soap-and-water wipes seem to be more effective in reducing skin infections compared with the no-treatment group.

  19. Therapeutic Effects of Erythroid Differentiation Regulator 1 on Imiquimod-Induced Psoriasis-Like Skin Inflammation.

    Science.gov (United States)

    Kim, Kyung Eun; Houh, Younkyung; Park, Hyun Jeong; Cho, Daeho

    2016-02-17

    Psoriasis is a common skin disease accompanied by chronic inflammation. In previous studies, erythroid differentiation regulator 1 (ERDR1) was shown to have a negative correlation with proinflammatory cytokine IL-18. However, the role of ERDR1 in the inflammatory skin disease psoriasis has not been evaluated. In this study, to investigate the role of ERDR1 in psoriasis, recombinant ERDR1 was injected intraperitoneally into a psoriasis mouse model. Recombinant ERDR1 (rERDR1) significantly alleviated the symptoms of psoriasis-like skin inflammation and reduced the mRNA of various psoriasis-related markers, including keratin 14, S100A8, and Th17-related cytokines IL-17 and IL-22, suggesting that rERDR1 exerts therapeutic effects on psoriasis via the regulation of Th17 functions. Additionally, the expression of CCL20, a well-known Th17 attracting chemokine, was determined. CCL20 expression significantly decreased in the rERDR1-injected group compared with the vehicle (PBS)-injected group. CCR6 expression in the psoriatic lesional skin was also decreased by rERDR1 administration, implying the inhibition of CCR6-expressing Th17 cell chemotaxis via the downregulation of CCL20. Taken together, this study provides the first evidence that ERDR1 may be a potential therapeutic target for psoriasis.

  20. Nonlinear regimes of forced magnetic reconnection

    Energy Technology Data Exchange (ETDEWEB)

    Vekstein, G., E-mail: g.vekstein@manchester.ac.uk [JBCA, School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); STEL, Nagoya University, Nagoya, Aichi 464-8601 (Japan); Kusano, K. [STEL, Nagoya University, Nagoya, Aichi 464-8601 (Japan)

    2015-09-15

    This letter presents a self-consistent description of nonlinear forced magnetic reconnection in Taylor's model of this process. If external boundary perturbation is strong enough, nonlinearity in the current sheet evolution becomes important before resistive effects come into play. This terminates the current sheet shrinking that takes place at the linear stage and brings about its nonlinear equilibrium with a finite thickness. Then, in theory, this equilibrium is destroyed by a finite plasma resistivity during the skin-time, and further reconnection proceeds in the Rutherford regime. However, realization of such a scenario is unlikely because of the plasmoid instability, which is fast enough to develop before the transition to the Rutherford phase occurs. The suggested analytical theory is entirely different from all previous studies and provides proper interpretation of the presently available numerical simulations of nonlinear forced magnetic reconnection.