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Sample records for biophysical parameters closely

  1. MODELLING BIOPHYSICAL PARAMETERS OF MAIZE USING LANDSAT 8 TIME SERIES

    Directory of Open Access Journals (Sweden)

    T. Dahms

    2016-06-01

    Full Text Available Open and free access to multi-frequent high-resolution data (e.g. Sentinel – 2 will fortify agricultural applications based on satellite data. The temporal and spatial resolution of these remote sensing datasets directly affects the applicability of remote sensing methods, for instance a robust retrieving of biophysical parameters over the entire growing season with very high geometric resolution. In this study we use machine learning methods to predict biophysical parameters, namely the fraction of absorbed photosynthetic radiation (FPAR, the leaf area index (LAI and the chlorophyll content, from high resolution remote sensing. 30 Landsat 8 OLI scenes were available in our study region in Mecklenburg-Western Pomerania, Germany. In-situ data were weekly to bi-weekly collected on 18 maize plots throughout the summer season 2015. The study aims at an optimized prediction of biophysical parameters and the identification of the best explaining spectral bands and vegetation indices. For this purpose, we used the entire in-situ dataset from 24.03.2015 to 15.10.2015. Random forest and conditional inference forests were used because of their explicit strong exploratory and predictive character. Variable importance measures allowed for analysing the relation between the biophysical parameters with respect to the spectral response, and the performance of the two approaches over the plant stock evolvement. Classical random forest regression outreached the performance of conditional inference forests, in particular when modelling the biophysical parameters over the entire growing period. For example, modelling biophysical parameters of maize for the entire vegetation period using random forests yielded: FPAR: R² = 0.85; RMSE = 0.11; LAI: R² = 0.64; RMSE = 0.9 and chlorophyll content (SPAD: R² = 0.80; RMSE=4.9. Our results demonstrate the great potential in using machine-learning methods for the interpretation of long-term multi-frequent remote sensing

  2. Modelling Biophysical Parameters of Maize Using Landsat 8 Time Series

    Science.gov (United States)

    Dahms, Thorsten; Seissiger, Sylvia; Conrad, Christopher; Borg, Erik

    2016-06-01

    Open and free access to multi-frequent high-resolution data (e.g. Sentinel - 2) will fortify agricultural applications based on satellite data. The temporal and spatial resolution of these remote sensing datasets directly affects the applicability of remote sensing methods, for instance a robust retrieving of biophysical parameters over the entire growing season with very high geometric resolution. In this study we use machine learning methods to predict biophysical parameters, namely the fraction of absorbed photosynthetic radiation (FPAR), the leaf area index (LAI) and the chlorophyll content, from high resolution remote sensing. 30 Landsat 8 OLI scenes were available in our study region in Mecklenburg-Western Pomerania, Germany. In-situ data were weekly to bi-weekly collected on 18 maize plots throughout the summer season 2015. The study aims at an optimized prediction of biophysical parameters and the identification of the best explaining spectral bands and vegetation indices. For this purpose, we used the entire in-situ dataset from 24.03.2015 to 15.10.2015. Random forest and conditional inference forests were used because of their explicit strong exploratory and predictive character. Variable importance measures allowed for analysing the relation between the biophysical parameters with respect to the spectral response, and the performance of the two approaches over the plant stock evolvement. Classical random forest regression outreached the performance of conditional inference forests, in particular when modelling the biophysical parameters over the entire growing period. For example, modelling biophysical parameters of maize for the entire vegetation period using random forests yielded: FPAR: R² = 0.85; RMSE = 0.11; LAI: R² = 0.64; RMSE = 0.9 and chlorophyll content (SPAD): R² = 0.80; RMSE=4.9. Our results demonstrate the great potential in using machine-learning methods for the interpretation of long-term multi-frequent remote sensing datasets to model

  3. Smoothing of, and parameter estimation from, noisy biophysical recordings.

    Directory of Open Access Journals (Sweden)

    Quentin J M Huys

    2009-05-01

    Full Text Available Biophysically detailed models of single cells are difficult to fit to real data. Recent advances in imaging techniques allow simultaneous access to various intracellular variables, and these data can be used to significantly facilitate the modelling task. These data, however, are noisy, and current approaches to building biophysically detailed models are not designed to deal with this. We extend previous techniques to take the noisy nature of the measurements into account. Sequential Monte Carlo ("particle filtering" methods, in combination with a detailed biophysical description of a cell, are used for principled, model-based smoothing of noisy recording data. We also provide an alternative formulation of smoothing where the neural nonlinearities are estimated in a non-parametric manner. Biophysically important parameters of detailed models (such as channel densities, intercompartmental conductances, input resistances, and observation noise are inferred automatically from noisy data via expectation-maximization. Overall, we find that model-based smoothing is a powerful, robust technique for smoothing of noisy biophysical data and for inference of biophysical parameters in the face of recording noise.

  4. Biophysics

    CERN Document Server

    Glaser, Roland

    1999-01-01

    The message of this book is that biophysics is the science of physical principles underlying the "phenomenon life" on all levels of organization. Rather than teaching "physics for biologists" or "physical methods applied to biology", it regards its subject as a defined discipline with its own network of ideas and approaches. The book starts by explaining molecular structures of biological systems, various kinds of atomic, molecular and ionic interactions, movements, energy transfer, self organization of supramolecular structures and dynamic properties of biological membranes. It then goes on to introduce the biological organism as a non-equilibrium system, before treating thermodynamic concepts of osmotic and electrolyte equilibria as well as currents and potential profiles. It continues with topics of environmental biophysics and such medical aspects as the influence of electromagnetic fields or radiation on living systems and the biophysics of hearing and noice protection. The book concludes with a discussi...

  5. Derivation of global vegetation biophysical parameters from EUMETSAT Polar System

    Science.gov (United States)

    García-Haro, Francisco Javier; Campos-Taberner, Manuel; Muñoz-Marí, Jordi; Laparra, Valero; Camacho, Fernando; Sánchez-Zapero, Jorge; Camps-Valls, Gustau

    2018-05-01

    This paper presents the algorithm developed in LSA-SAF (Satellite Application Facility for Land Surface Analysis) for the derivation of global vegetation parameters from the AVHRR (Advanced Very High Resolution Radiometer) sensor on board MetOp (Meteorological-Operational) satellites forming the EUMETSAT (European Organization for the Exploitation of Meteorological Satellites) Polar System (EPS). The suite of LSA-SAF EPS vegetation products includes the leaf area index (LAI), the fractional vegetation cover (FVC), and the fraction of absorbed photosynthetically active radiation (FAPAR). LAI, FAPAR, and FVC characterize the structure and the functioning of vegetation and are key parameters for a wide range of land-biosphere applications. The algorithm is based on a hybrid approach that blends the generalization capabilities offered by physical radiative transfer models with the accuracy and computational efficiency of machine learning methods. One major feature is the implementation of multi-output retrieval methods able to jointly and more consistently estimate all the biophysical parameters at the same time. We propose a multi-output Gaussian process regression (GPRmulti), which outperforms other considered methods over PROSAIL (coupling of PROSPECT and SAIL (Scattering by Arbitrary Inclined Leaves) radiative transfer models) EPS simulations. The global EPS products include uncertainty estimates taking into account the uncertainty captured by the retrieval method and input errors propagation. A sensitivity analysis is performed to assess several sources of uncertainties in retrievals and maximize the positive impact of modeling the noise in training simulations. The paper discusses initial validation studies and provides details about the characteristics and overall quality of the products, which can be of interest to assist the successful use of the data by a broad user's community. The consistent generation and distribution of the EPS vegetation products will

  6. Biophysics

    International Nuclear Information System (INIS)

    Danyluk, S.S.

    1975-01-01

    Research is reported on magnetic resonance spectroscopy of biological molecules, development of clinical applications of stable isotopes, circadian cybernetics, and X-ray crystallography of immunoglobulins. Biological processes occur in fluid media, and ultimately our knowledge of their mechanisms requires detailed information for chemical and molecular structural properties in biological fluids. Magnetic resonance spectroscopy has unique advantages over other approaches in this area that are being exploited in studies currently underway in the group. The program continues to develop along three interrelated lines, measurement and analysis of high resolution spectra for biological molecules (especially nucleic acid constituents and drugs), synthesis of selectively labeled nucleic acid fragments essential for complete spectral assignments, and computation of conformational properties from NMR parameters. This coordinated approach enabled the first complete conformation analysis for a dinucleoside monophosphate, ApA, in aqueous solution. It was found that the conformation is actually a time-average of right helical, loop, and extended conformations, the interchange being extremely rapid on an NMR time scale. Spectral analyses were also completed for all possible ribonucleotide dimers, the assignments again relying heavily on synthesis of appropriate deuterated counterparts. Studies of conformational flexibility in nucleic acid fragments showed that changes in hydrogen ion concentration and temperature produce correlated conformational changes specific for each nucleotidyl unit. Studies were also initiated in three new projects dealing with the effect of hapten binding on antibody structure, counter ion influence on nucleic acid free radicals, and membrane differences between normal and sickled erythrocytes

  7. Measurement of some biophysical parameters in skin lesions of leprosy

    Directory of Open Access Journals (Sweden)

    A B Gupta

    1990-01-01

    Full Text Available Transepidermal water loss (TEWL, high frequency electrical conductance (HFC and the hydration state index (HSI were measured in sldn lesions of 30 paucibacillary leprosy patients and compared with the contralateral uninvolved skin. While the TEWL, HFC and HSI all showed lower values in the lesion site, as compared to the contralateral skin sites, the differences between the two sets of values significant in HFC and. HSI only at 2% and 1% level respectively. A significant positive correlation (r = 0.69 was found to eidst between these two parameters. The parameters correlate well with the known reduced sweating in skin lesions of TT and BT leprosy and may therefore be considered as good objective parameters to confirm hypohydrosis in suspected skin lesions ofleprosy.

  8. Heavy particle track structure parameters for biophysical modelling

    International Nuclear Information System (INIS)

    Watt, D.E.

    1994-01-01

    Averaged values of physical track structure parameters are important in radiobiology and radiological protection for the expression of damage mechanisms and for quantifying radiation effects. To provide a ready reference, tables of relevant quantities have been compiled for heavy charged particles in liquid water. The full tables will be published elsewhere but here illustrative examples are given of the trends for the most important quantities. In the tables, data are given for 74 types of heavy charged particle ranging from protons to uranium ions at specific energies between 0.1 keV/u and 1 GeV/u. Aggregate effects in liquid water are taken into account implicitly in the calculations. Results are presented for instantaneous particle energies and for averages over the charged particle equilibrium spectrum. The latter are of special relevance to radiation dosimetry. Quality parameters calculated are: β 2 ; z 2 /β 2 ; linear primary ionisation and the mean free path between ionisations; LET; track and dose-restricted LET with 100 eV cut-off; relative variances; delta-ray energies and ranges; ion energies and ranges and kerma factors. Here, the procedures used in the calculations are indicated. Representative results are shown in graphical form. The role of the physical track properties is discussed with regard to optimisation of the design of experiments intended to elucidate biological damage mechanisms in mammalian cells and their relevance to radiological protection. ((orig.))

  9. Resolving the biophysics of axon transmembrane polarization in a single closed-form description

    Energy Technology Data Exchange (ETDEWEB)

    Melendy, Robert F., E-mail: rfmelendy@liberty.edu [School of Engineering and Computational Sciences, Liberty University, Lynchburg, Virginia 24515 (United States)

    2015-12-28

    When a depolarizing event occurs across a cell membrane there is a remarkable change in its electrical properties. A complete depolarization event produces a considerably rapid increase in voltage that propagates longitudinally along the axon and is accompanied by changes in axial conductance. A dynamically changing magnetic field is associated with the passage of the action potential down the axon. Over 75 years of research has gone into the quantification of this phenomenon. To date, no unified model exist that resolves transmembrane polarization in a closed-form description. Here, a simple but formative description of propagated signaling phenomena in the membrane of an axon is presented in closed-form. The focus is on using both biophysics and mathematical methods for elucidating the fundamental mechanisms governing transmembrane polarization. The results presented demonstrate how to resolve electromagnetic and thermodynamic factors that govern transmembrane potential. Computational results are supported by well-established quantitative descriptions of propagated signaling phenomena in the membrane of an axon. The findings demonstrate how intracellular conductance, the thermodynamics of magnetization, and current modulation function together in generating an action potential in a unified closed-form description. The work presented in this paper provides compelling evidence that three basic factors contribute to the propagated signaling in the membrane of an axon. It is anticipated this work will compel those in biophysics, physical biology, and in the computational neurosciences to probe deeper into the classical and quantum features of membrane magnetization and signaling. It is hoped that subsequent investigations of this sort will be advanced by the computational features of this model without having to resort to numerical methods of analysis.

  10. Satellite mapping of surface biophysical parameters at the biome scale over the North American grasslands: A case study

    Science.gov (United States)

    Wylie, B.K.; Meyer, D.J.; Tieszen, L.L.; Mannel, S.

    2002-01-01

    Quantification of biophysical parameters is needed by terrestrial process modeling and other applications. A study testing the role of multispectral data for monitoring biophysical parameters was conducted over a network of grassland field sites in the Great Plains of North America. Grassland biophysical parameters [leaf area index (LAI), fraction of absorbed photosynthetically active radiation (fPAR), and biomass] and their relationships with ground radiometer normalized difference vegetation index (NDVI) were established in this study (r2=.66–.85) from data collected across the central and northern Great Plains in 1995. These spectral/biophysical relationships were compared to 1996 field data from the Tallgrass Prairie Preserve in northeastern Oklahoma and showed no consistent biases, with most regression estimates falling within the respective 95% confidence intervals. Biophysical parameters were estimated for 21 “ground pixels” (grids) at the Tallgrass Prairie Preserve in 1996, representing three grazing/burning treatments. Each grid was 30×30 m in size and was systematically sampled with ground radiometer readings. The radiometric measurements were then converted to biophysical parameters and spatially interpolated using geostatistical kriging. Grid-based biophysical parameters were monitored through the growing season and regressed against Landsat Thematic Mapper (TM) NDVI (r2=.92–.94). These regression equations were used to estimate biophysical parameters for grassland TM pixels over the Tallgrass Prairie Preserve in 1996. This method maintained consistent regression development and prediction scales and attempted to minimize scaling problems associated with mixed land cover pixels. A method for scaling Landsat biophysical parameters to coarser resolution satellite data sets (1 km2) was also investigated.

  11. Variation of Biophysical Parameters of the Skin with Age, Gender, and Body Region

    Science.gov (United States)

    Firooz, Alireza; Sadr, Bardia; Babakoohi, Shahab; Sarraf-Yazdy, Maryam; Fanian, Ferial; Kazerouni-Timsar, Ali; Nassiri-Kashani, Mansour; Naghizadeh, Mohammad Mehdi; Dowlati, Yahya

    2012-01-01

    Background. Understanding the physiological, chemical, and biophysical characteristics of the skin helps us to arrange a proper approach to the management of skin diseases. Objective. The aim of this study was to measure 6 biophysical characteristics of normal skin (sebum content, hydration, transepidermal water loss (TEWL), erythema index, melanin index, and elasticity) in a normal population and assess the effect of sex, age, and body location on them. Methods. Fifty healthy volunteers in 5 age groups (5 males and females in each) were enrolled in this study. A multifunctional skin physiology monitor (Courage & Khazaka electronic GmbH, Germany) was used to measure skin sebum content, hydration, TEWL, erythema index, melanin index, and elasticity in 8 different locations of the body. Results. There were significant differences between the hydration, melanin index, and elasticity of different age groups. Regarding the locations, forehead had the highest melanin index, where as palm had the lowest value. The mean values of erythema index and melanin index and TEWL were significantly higher in males and anatomic location was a significant independent factor for all of 6 measured parameters. Conclusion. Several biophysical properties of the skin vary among different gender, age groups, and body locations. PMID:22536139

  12. Urban thermal environment and its biophysical parameters derived from satellite remote sensing imagery

    Science.gov (United States)

    Zoran, Maria A.; Savastru, Roxana S.; Savastru, Dan M.; Tautan, Marina N.; Baschir, Laurentiu V.

    2013-10-01

    In frame of global warming, the field of urbanization and urban thermal environment are important issues among scientists all over the world. This paper investigated the influences of urbanization on urban thermal environment as well as the relationships of thermal characteristics to other biophysical variables in Bucharest metropolitan area of Romania based on satellite remote sensing imagery Landsat TM/ETM+, time series MODIS Terra/Aqua data and IKONOS acquired during 1990 - 2012 period. Vegetation abundances and percent impervious surfaces were derived by means of linear spectral mixture model, and a method for effectively enhancing impervious surface has been developed to accurately examine the urban growth. The land surface temperature (Ts), a key parameter for urban thermal characteristics analysis, was also retrieved from thermal infrared band of Landsat TM/ETM+, from MODIS Terra/Aqua datasets. Based on these parameters, the urban growth, urban heat island effect (UHI) and the relationships of Ts to other biophysical parameters have been analyzed. Results indicated that the metropolitan area ratio of impervious surface in Bucharest increased significantly during two decades investigated period, the intensity of urban heat island and heat wave events being most significant. The correlation analyses revealed that, at the pixel-scale, Ts possessed a strong positive correlation with percent impervious surfaces and negative correlation with vegetation abundances at the regional scale, respectively. This analysis provided an integrated research scheme and the findings can be very useful for urban ecosystem modeling.

  13. Maximum likelihood estimation of biophysical parameters of synaptic receptors from macroscopic currents

    Directory of Open Access Journals (Sweden)

    Andrey eStepanyuk

    2014-10-01

    Full Text Available Dendritic integration and neuronal firing patterns strongly depend on biophysical properties of synaptic ligand-gated channels. However, precise estimation of biophysical parameters of these channels in their intrinsic environment is complicated and still unresolved problem. Here we describe a novel method based on a maximum likelihood approach that allows to estimate not only the unitary current of synaptic receptor channels but also their multiple conductance levels, kinetic constants, the number of receptors bound with a neurotransmitter and the peak open probability from experimentally feasible number of postsynaptic currents. The new method also improves the accuracy of evaluation of unitary current as compared to the peak-scaled non-stationary fluctuation analysis, leading to a possibility to precisely estimate this important parameter from a few postsynaptic currents recorded in steady-state conditions. Estimation of unitary current with this method is robust even if postsynaptic currents are generated by receptors having different kinetic parameters, the case when peak-scaled non-stationary fluctuation analysis is not applicable. Thus, with the new method, routinely recorded postsynaptic currents could be used to study the properties of synaptic receptors in their native biochemical environment.

  14. Effects of LiDAR point density, sampling size and height threshold on estimation accuracy of crop biophysical parameters.

    Science.gov (United States)

    Luo, Shezhou; Chen, Jing M; Wang, Cheng; Xi, Xiaohuan; Zeng, Hongcheng; Peng, Dailiang; Li, Dong

    2016-05-30

    Vegetation leaf area index (LAI), height, and aboveground biomass are key biophysical parameters. Corn is an important and globally distributed crop, and reliable estimations of these parameters are essential for corn yield forecasting, health monitoring and ecosystem modeling. Light Detection and Ranging (LiDAR) is considered an effective technology for estimating vegetation biophysical parameters. However, the estimation accuracies of these parameters are affected by multiple factors. In this study, we first estimated corn LAI, height and biomass (R2 = 0.80, 0.874 and 0.838, respectively) using the original LiDAR data (7.32 points/m2), and the results showed that LiDAR data could accurately estimate these biophysical parameters. Second, comprehensive research was conducted on the effects of LiDAR point density, sampling size and height threshold on the estimation accuracy of LAI, height and biomass. Our findings indicated that LiDAR point density had an important effect on the estimation accuracy for vegetation biophysical parameters, however, high point density did not always produce highly accurate estimates, and reduced point density could deliver reasonable estimation results. Furthermore, the results showed that sampling size and height threshold were additional key factors that affect the estimation accuracy of biophysical parameters. Therefore, the optimal sampling size and the height threshold should be determined to improve the estimation accuracy of biophysical parameters. Our results also implied that a higher LiDAR point density, larger sampling size and height threshold were required to obtain accurate corn LAI estimation when compared with height and biomass estimations. In general, our results provide valuable guidance for LiDAR data acquisition and estimation of vegetation biophysical parameters using LiDAR data.

  15. Online determination of biophysical parameters of mucous membranes of a human body

    Energy Technology Data Exchange (ETDEWEB)

    Lisenko, S A; Kugeiko, M M [Belarusian State University, Minsk (Belarus)

    2013-07-31

    We have developed a method for online determination of biophysical parameters of mucous membranes (MMs) of a human body (transport scattering coefficient, scattering anisotropy factor, haemoglobin concentration, degrees of blood oxygenation, average diameter of capillaries with blood) from measurements of spectral and spatial characteristics of diffuse reflection. The method is based on regression relationships between linearly independent components of the measured light signals and the unknown parameters of MMs, obtained by simulation of the radiation transfer in the MM under conditions of its general variability. We have proposed and justified the calibration-free fibre-optic method for determining the concentration of haemoglobin in MMs by measuring the light signals diffusely reflected by the tissue in four spectral regions at two different distances from the illumination spot. We have selected the optimal wavelengths of optical probing for the implementation of the method. (laser applications in biology and medicine)

  16. Retrieval of biophysical parameters with AVIRIS and ISM: The Landes Forest, south west France

    Science.gov (United States)

    Zagolski, F.; Gastellu-Etchegorry, J. P.; Mougin, E.; Giordano, G.; Marty, G.; Letoan, T.; Beaudoin, A.

    1992-01-01

    The first steps of an experiment for investigating the capability of airborne spectrometer data for retrieval of biophysical parameters of vegetation, especially water conditions are presented. Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and ISM data were acquired in the frame of the 1991 NASA/JPL and CNES campaigns on the Landes, South west France, a large and flat forest area with mainly maritime pines. In-situ measurements were completed at that time; i.e. reflectance spectra, atmospheric profiles, sampling for further laboratory analyses of elements concentrations (lignin, water, cellulose, nitrogen,...). All information was integrated in an already existing data base (age, LAI, DBH, understory cover,...). A methodology was designed for (1) obtaining geometrically and atmospherically corrected reflectance data, (2) registering all available information, and (3) analyzing these multi-source informations. Our objective is to conduct comparative studies with simulation reflectance models, and to improve these models, especially in the MIR.

  17. A multivariate analysis of biophysical parameters of tallgrass prairie among land management practices and years

    Science.gov (United States)

    Griffith, J.A.; Price, K.P.; Martinko, E.A.

    2001-01-01

    Six treatments of eastern Kansas tallgrass prairie - native prairie, hayed, mowed, grazed, burned and untreated - were studied to examine the biophysical effects of land management practices on grasslands. On each treatment, measurements of plant biomass, leaf area index, plant cover, leaf moisture and soil moisture were collected. In addition, measurements were taken of the Normalized Difference Vegetation Index (NDVI), which is derived from spectral reflectance measurements. Measurements were taken in mid-June, mid-July and late summer of 1990 and 1991. Multivariate analysis of variance was used to determine whether there were differences in the set of variables among treatments and years. Follow-up tests included univariate t-tests to determine which variables were contributing to any significant difference. Results showed a significant difference (p treatments in the composite of parameters during each of the months sampled. In most treatment types, there was a significant difference between years within each month. The univariate tests showed, however, that only some variables, primarily soil moisture, were contributing to this difference. We conclude that biomass and % plant cover show the best potential to serve as long-term indicators of grassland condition as they generally were sensitive to effects of different land management practices but not to yearly change in weather conditions. NDVI was insensitive to precipitation differences between years in July for most treatments, but was not in the native prairie. Choice of sampling time is important for these parameters to serve effectively as indicators.

  18. Evaluation of biophysical skin parameters and assessment of hair growth in patients with acne treated with isotretinoin.

    Science.gov (United States)

    Kmieć, Małgorzata L; Pajor, Anna; Broniarczyk-Dyła, Grażyna

    2013-12-01

    Treatment of the severe forms of acne vulgaris remains a challenge. Isotretinoin is a drug often used in these cases. Retinoids affect the mechanisms that play a role in the pathogenesis of acne, reduce the production of sebum and sizes of the sebaceous glands. However, isotretinoin appears to have undesirable side effects in the skin, mucous membranes and hair. THE AIM OF THIS STUDY WAS TO ASSESS THE EFFECT OF ACNE VULGARIS TREATMENT WITH ISOTRETINOIN ON BIOPHYSICAL SKIN PARAMETERS: skin sebum and stratum corneum hydration levels, transepidermal water loss values, pH, erythema and hair growth parameters: total number, density and proportion of anagen hair. THE STUDY INCLUDED THIRTY PATIENTS WITH ACNE TYPES: papulopustular, conglobata and phlegmonosa. Patients were treated with isotretinoin at a dose of 0.5-1.0 mg/kg/day for a period of 4-7 months. The measurements of skin biophysical parameters were performed before and after the treatment using Sebumeter SM815, Corneometer CM825, Tewameter TM300, MX Mexameter MX18 and Skin-pH-Meter PH908. Hair growth parameters were evaluated with FotoFinder Dermoscope using the TrichoScan Professional V3.0.8.76 software. The results of biophysical skin parameter measurements after the treatment showed a reduction in the severity of seborrhea. However, the skin was dry, which confirmed a lowered degree of stratum corneum hydration and an increase in transepidermal water loss values. Moreover, severity of erythema, an increase in pH value, and variations in selected hair growth parameters: decrease in total count, density and proportion of anagen hair were demonstrated. The reduction in the skin sebum levels was observed after the treatment. There was dryness of the skin, which was confirmed by biophysical skin parameter measurements. Changes in the hair growth parameters showed telogen effluvium hair loss.

  19. Effect of maternal exercises on biophysical fetal and maternal parameters: a transversal study.

    Science.gov (United States)

    Santos, Caroline Mombaque Dos; Santos, Wendel Mombaque Dos; Gallarreta, Francisco Maximiliano Pancich; Pigatto, Camila; Portela, Luiz Osório Cruz; Morais, Edson Nunes de

    2016-01-01

    To evaluate the acute effects of maternal and fetal hemodynamic responses in pregnant women submitted to fetal Doppler and an aerobic physical exercise test according to the degree of effort during the activity and the impact on the well-being. Transversal study with low risk pregnant women, obtained by convenience sample with gestational age between 26 to 34 weeks. The participants carry out a progressive exercise test. After the exercise session, reduced resistance (p=0.02) and pulsatility indices (p=0.01) were identified in the umbilical artery; however, other Doppler parameters analyzed, in addition to cardiotocography and fetal biophysical profile did not achieve significant change. Maternal parameters obtained linear growth with activity, but it was not possible to establish a standard with the Borg scale, and oxygen saturation remained stable. A short submaximal exercise had little effect on placental blood flow after exercise in pregnancies without complications, corroborating that healthy fetus maintains homeostasis even in situations that alter maternal hemodynamics. Avaliar os efeitos agudos de respostas hemodinâmicas maternas e fetais em gestantes submetidas a Doppler fetal e a um teste de exercício físico aeróbio, de acordo com o grau de esforço durante a atividade e o impacto sobre o bem-estar. Estudo transversal desenvolvido com gestantes de baixo risco, por amostra de conveniência com idade gestacional entre 26 e 34 semanas. As participantes realizam um teste de esforço progressivo. Na artéria umbilical, após sessão de exercício físico, identificou-se a redução do índice de resistência (p=0,02) e do índice de pulsatilidade (p=0,01), mas os demais parâmetros Doppler analisados, além da cardiotocografia e do perfil biofísico fetal, não obtiveram alteração significativa. Os parâmetros maternos obtiveram crescimento linear com a atividade, mas não foi possível estabelecer padrão com a escala de Borg, e a saturação de oxig

  20. Monitoring and ming bio-physical parameters for hypoxia hazard in a coastal sand pit

    DEFF Research Database (Denmark)

    Mariani, Patrizio; Benassai, Guido; Grieco, Luisa

    2018-01-01

    Management of coastal areas requires monitoring and modeling of the anthropogenic drivers and the bio-physical processes affecting water quality. To assess the range of hydrographic conditions controlling oxygen distribution in the bottom layers of sand pits, a multi-year oceanographic survey has...... of the sand pits is associated with higher temperatures and wind speed lower than 5 m/s, which is not infrequent during the summer season. However, the number of consecutive days of oxygen depletion can be considered lower than the danger threshold level assumed in the literature....

  1. Radiation dosimetry and radiation biophysics

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    Radiation dosimetry and radiation biophysics are two closely integrated programs whose joint purpose is to explore the connections between the primary physical events produced by radiation and their biological consequences in cellular systems. The radiation dosimetry program includes the theoretical description of primary events and their connection with the observable biological effects. This program also is concerned with the design and measurement of physical parameters used in theory or to support biological experiments. The radiation biophysics program tests and uses the theoretical developments for experimental design, and provides information for further theoretical development through experiments on cellular systems

  2. Radiation dosimetry and radiation biophysics

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    Radiation dosimetry and radiation biophysics are two closely integrated programs whose joint purpose is to explore the connections between the primary physical events produced by radiation and their biological consequences in cellular systems. The radiation dosimetry program includes the theoretical description of primary events and their connection with the observable biological effects. This program also is concerned with design and measurement of those physical parameters used in the theory or to support biological experiments. The radiation biophysics program tests and makes use of the theoretical developments for experimental design. Also, this program provides information for further theoretical development through experiments on cellular systems

  3. DEPENDENCE OF THE SPECKLE-PATTERNS SIZE AND THEIR CONTRAST ON THE BIOPHYSICAL AND STRUCTURAL PARAMETERS OF BIOLOGICAL TISSUES

    Directory of Open Access Journals (Sweden)

    N. D. Abramovich

    2017-01-01

    Full Text Available Speckle fields are widely used in optical diagnostics of biotissues and evaluation of the functional state of bioobjects. The speckle field is formed by laser radiation scattered from the object under study. It bears information about the average dimensions of the scatterers, the degree of surface roughness makes it possible to judge the structural and biophysical characteristics of individual tissue cells (particles, on the one hand, and the integral optical characteristics of the entire biological tissue. The aim of the study was – the determination of connections between the biophysical and structural characteristics of the biotissue and the light fields inside the biotissues.The model developed of the medium gives a direct relationship between the optical and biophysical parameters of the biotissue. Calculations were carried out using known solutions of the radiation transfer equation, taking into account the multilayer structure of the tissue, multiple scattering in the medium, and multiple reflection of irradiation between the layers.With the increase wavelength, the size of speckles formed by the non-scattered component (direct light of laser radiation increases by a factor of 2 from 400 to 800 μm in the stratum corneum and 5 times from 0.6 to 3 μm for the epidermis and from 0.27 to 1.4 μm to the dermis. Typical values of sizes of speckles formed by the diffraction component of laser radiation for the stratum corneum and epidermis range from 0.02 to 0.15 μm. For the dermis typical spot sizes are up to 0.03 μm. The speckle-spot size of the diffusion component in the dermis can vary from ±10 % at 400 nm and up to ±23 % for 800 nm when the volume concentration of blood capillaries changes. Characteristic dependencies are obtained and biophysical factors associated with the volume concentration of blood and the degree of it’s oxygenation that affect the contrast of the speckle structure in the dermis are discussed.The of speckles

  4. Relation between soil temperature and biophysical parameters in Indian mustard seeds

    Science.gov (United States)

    Adak, T.; Chakravarty, N. V. K.

    2013-12-01

    Temporal changes in surface soil temperature were studied in winter crop. Significant changes in bare and cropped soil temperature were revealed. Air temperature showed a statistically positive and strong relationship (R2 = 0.79** to 0.92**) with the soil temperature both at morning and afternoon hours. Linear regression analysis indicated that each unit increase in ambient temperature would lead to increase in minimum and maximum soil temperatures by 1.04 and 1.02 degree, respectively. Statistically positive correlation was revealed among biophysical variables with the cumulative surface soil temperature. Linear and non-linear regression analysis indicated 62-69, 72-86 and 72-80% variation in Leaf area index, dry matter production and heat use efficiency in Indian mustard crop as a function of soil degree days. Below 60% variation in yield in Indian mustard was revealed as a function of soil temperature. In contrast, non-significant relationship between oil content and soil temperature was found, which suggests that oil accumulation in oilseed crops was not affected significantly by the soil temperature as an independent variable.

  5. Use of passive UAS imaging to measure biophysical parameters in a southern Rocky Mountain subalpine forest

    Science.gov (United States)

    Caldwell, M. K.; Sloan, J.; Mladinich, C. S.; Wessman, C. A.

    2013-12-01

    Unmanned Aerial Systems (UAS) can provide detailed, fine spatial resolution imagery for ecological uses not otherwise obtainable through standard methods. The use of UAS imagery for ecology is a rapidly -evolving field, where the study of forest landscape ecology can be augmented using UAS imagery to scale and validate biophysical data from field measurements to spaceborne observations. High resolution imagery provided by UAS (30 cm2 pixels) offers detailed canopy cover and forest structure data in a time efficient and inexpensive manner. Using a GoPro Hero2 (2 mm focal length) camera mounted in the nose cone of a Raven unmanned system, we collected aerial and thermal data monthly during the summer 2013, over two subalpine forests in the Southern Rocky Mountains in Colorado. These forests are dominated by lodgepole pine (Pinus ponderosae) and have experienced insect-driven (primarily mountain pine beetle; MPB, Dendroctonus ponderosae) mortality. Objectives of this study include observations of forest health variables such as canopy water content (CWC) from thermal imagery and leaf area index (LAI), biomass and forest productivity from the Normalized Difference Vegetation Index (NDVI) from UAS imagery. Observations were, validated with ground measurements. Images were processed using a combination of AgiSoft Photoscan professional software and ENVI remote imaging software. We utilized the software Leaf Area Index Calculator (LAIC) developed by Córcoles et al. (2013) for calculating LAI from digital images and modified to conform to leaf area of needle-leaf trees as in Chen and Cihlar (1996) . LAIC uses a K-means cluster analysis to decipher the RGB levels for each pixel and distinguish between green aboveground vegetation and other materials, and project leaf area per unit of ground surface area (i.e. half total needle surface area per unit area). Preliminary LAIC UAS data shows summer average LAI was 3.8 in the most dense forest stands and 2.95 in less dense

  6. Biophysical parameters of erythrocyte membranes and mechanisms of interaction with non-opioid analgesics under acute pain syndrome

    Directory of Open Access Journals (Sweden)

    Yu. I. Gubskyi

    2014-06-01

    Full Text Available Methods of fluorescent probing, spectrophotometry and microcalorimetry were applied to investigate the alterations in biophysical parameters of erythrocytes membranes, and specifically microviscosity, surface charge, molecular organization of lipid bilayer and lipid-protein interactions under conditions of acute pain syndrome produced by experimental chemical lesion. The distinctive features of non-opiod analgesics interactions and binding to the erythrocytes membranes of rats subjected to acute nociceptive pain accompanied with oxidative stress development were investigated. The abilities of analgesics under research, and namely paracetamol, aspirin, phenazone, ketorolac, pyrodazole, ketoprofenum, natrium mefenaminate, indometacin, nimesulide to make up physico-chemical complexes with lipoperoxidation modified erythrocytes surface and protein-lipid bilayer showed marked changes. The significance of oxidative damage of biophase under conditions of acute pain syndrome for analgesics effective pharmacodynamics and pharmacokinetics realization is under consideration.

  7. Temporal analysis of vegetation indices related to biophysical parameters using Sentinel 2A images to estimate maize production

    Science.gov (United States)

    Macedo, Lucas Saran; Kawakubo, Fernando Shinji

    2017-10-01

    Agricultural production is one of the most important Brazilian economic activities accounting for about 21,5% of total Gross Domestic Product. In this scenario, the use of satellite images for estimating biophysical parameters along the phenological development of agricultural crops allows the conclusion about the sanity of planting and helps the projection on design production trends. The objective of this study is to analyze the temporal patterns and variation of six vegetion indexes obtained from the bands of Sentinel 2A satellite, associated with greenness (NDVI and ClRE), senescence (mARI and PSRI) and water content (DSWI and NDWI) to estimate maize production. The temporal pattern of the indices was analyzed in function of productivity data collected in-situ. The results obtained evidenced the importance of the SWIR and Red Edge ranges with Pearson correlation values of the temporal mean for NDWI 0.88 and 0.76 for CLRE.

  8. Numerical simulation on geometrical parameters for closed sump

    Science.gov (United States)

    Wang, Y. X.; Cheng, L.; Xia, C. Z.; Zhou, J. R.; Yan, H. Q.; Jiang, H. Y.

    2016-05-01

    The closed sump is a typical inlet passage of middle and small pumping station. It has the characteristics of low channel height, small foundation excavation depth, simple structure, a single cross sectional shape changes, ease of construction and other features, so more and more attention and application has been paying on this closed sump in pumping station project. However the flowing pattern within the closed sump is complex, the design is not perfect in some respects, the structure size does not be optimized. Based on the background for renewal and transformation of a pumping station, according to the three-dimensional incompressible fluid Reynolds-averaged N-S equations, the RNG k-e model, the CFD technology. The study on the draught in closed sump might reduce the length of pump shaft to enhance the stability of the pump unit operation. The results reveal the effect of the change of the height of plate. The turbulence in back wall might cause vortex when the height is high. The height of plate had be recommended control in 0.65D-0.85D.The better parameter combination of geometry of closed sump had be given through comparing the results of the orthogonal test and the comprehensive test. The floor clearance should be control in 1.0D. (D is the diameter of flared pipe)

  9. Mapping of Biophysical Parameters of Rice Agriculture System from Hyperspectral Imagery

    Science.gov (United States)

    Moharana, Shreedevi; Duta, Subashisa

    2017-04-01

    Chlorophyll, nitrogen and leaf water content are the most essential parameters for paddy crop growth. Ground hyperspectral observations were collected at canopy level during critical growth period of rice by using hand held Spectroradiometer. Chemical analysis was carried out to quantify the total chlorophyll, nitrogen and leaf water content. By exploiting the in-situ hyperspectral measurements, regression models were established between each of the crop growth parameters and the spectral indices specifically designed for chlorophyll, nitrogen and water stress. Narrow band vegetation index models were developed for mapping these parameters from Hyperion imagery in an agriculture system. It was inferred that the modified simple ratio (SR) and leaf nitrogen concentration (LNC) predictive index models, which followed a linear and nonlinear relationship respectively, produced satisfactory results in predicting rice nitrogen content from hyperspectral imagery. The presently developed model was compared with other models proposed by researchers. It was ascertained that, nitrogen content varied widely from 1-4 percentage and only 2-3 percentage for paddy crop using present modified index models and well-known predicted Tian et al. (2011) model respectively. The modified present LNC index model performed better than the established Tian et al. (2011) model as far as the estimated nitrogen content from Hyperion imagery was concerned. Moreover, within the observed chlorophyll range attained from the rice genotypes cultivated in the studied rice agriculture system, the index models (LNC, OASVI, Gitelson, mSR and MTCI) accomplished satisfactory results in the spatial distribution of rice chlorophyll content from Hyperion imagery. Spatial distribution of total chlorophyll content widely varied from 1.77-5.81 mg/g (LNC), 3.0-13 mg/g (OASVI) and 2.90-5.40 mg/g (MTCI). Following the similar guideline, it was found that normalized difference water index (NDWI) and normalized

  10. The Age Factor in the Cosmetic Management of Biophysical Skin Parameters

    Directory of Open Access Journals (Sweden)

    Claudia Cartigliani

    2014-06-01

    Full Text Available In this study we investigated the correlation between the basal skin hydration data, elasticity and surface roughness and the age of volunteers. Then, we analyzed the variations obtained at the end of the treatments with anti-age cosmetic products for the face. The aim was to investigate the susceptibility to improvement of volunteers from different age groups. Data were collected in our testing laboratory based in Milan over a 6-year long activity. We only considered measurements performed on the face of a female population aged between 18 and 70 years of age. Values were subdivided in age groups for each considered parameter and were statistically compared. As expected, skin roughness increased and R2 elasticity parameter decreased with ageing, while hydration values resulted to be higher in older women. Apparently, this unaccountable result is probably due to the fact that elderly women living in urban areas tend to take appropriate care of their skin, thus improving skin hydration effectively. Interestingly, as for skin hydration, the analysis showed that women aged 61–70 were the most susceptible to improvement induced by several types of cosmetic treatments. However, when considering the skin roughness values, women over 50 years old seemed to react better to cosmetic treatment. As for skin elasticity, the highest improvement values were found with women between 31 and 50 years of age.

  11. Detection and isolation of cell-derived microparticles are compromised by protein complexes resulting from shared biophysical parameters.

    Science.gov (United States)

    György, Bence; Módos, Károly; Pállinger, Eva; Pálóczi, Krisztina; Pásztói, Mária; Misják, Petra; Deli, Mária A; Sipos, Aron; Szalai, Anikó; Voszka, István; Polgár, Anna; Tóth, Kálmán; Csete, Mária; Nagy, György; Gay, Steffen; Falus, András; Kittel, Agnes; Buzás, Edit I

    2011-01-27

    Numerous diseases, recently reported to associate with elevated microvesicle/microparticle (MP) counts, have also long been known to be characterized by accelerated immune complex (IC) formation. The goal of this study was to investigate the potential overlap between parameters of protein complexes (eg, ICs or avidin-biotin complexes) and MPs, which might perturb detection and/or isolation of MPs. In this work, after comprehensive characterization of MPs by electron microscopy, atomic force microscopy, dynamic light-scattering analysis, and flow cytometry, for the first time, we drive attention to the fact that protein complexes, especially insoluble ICs, overlap in biophysical properties (size, light scattering, and sedimentation) with MPs. This, in turn, affects MP quantification by flow cytometry and purification by differential centrifugation, especially in diseases in which IC formation is common, including not only autoimmune diseases, but also hematologic disorders, infections, and cancer. These data may necessitate reevaluation of certain published data on patient-derived MPs and contribute to correct the clinical laboratory assessment of the presence and biologic functions of MPs in health and disease.

  12. Contactless diagnostics of biophysical parameters of skin and blood on the basis of approximating functions for radiation fluxes scattered by skin

    Energy Technology Data Exchange (ETDEWEB)

    Lisenko, S A; Kugeiko, M M [Belarusian State University, Minsk (Belarus)

    2014-03-28

    Approximating expressions are derived to calculate spectral and spatial characteristics of diffuse reflection of light from a two-layer medium mimicking human skin. The effectiveness of the use of these expressions in the optical diagnosis of skin biophysical parameters (tissue scattering parameters, concentration of melanin in the epidermis, concentration of total haemoglobin and bilirubin in the tissues of the dermis) and content of haemoglobin derivatives in blood (oxy-, deoxy-, met-, carboxy- and sulfhaemoglobin) is analysed numerically. The methods are proposed to determine in realtime these parameters without contact of the measuring instrument with the patient's body. (biophotonics)

  13. Contactless diagnostics of biophysical parameters of skin and blood on the basis of approximating functions for radiation fluxes scattered by skin

    Science.gov (United States)

    Lisenko, S. A.; Kugeiko, M. M.

    2014-03-01

    Approximating expressions are derived to calculate spectral and spatial characteristics of diffuse reflection of light from a two-layer medium mimicking human skin. The effectiveness of the use of these expressions in the optical diagnosis of skin biophysical parameters (tissue scattering parameters, concentration of melanin in the epidermis, concentration of total haemoglobin and bilirubin in the tissues of the dermis) and content of haemoglobin derivatives in blood (oxy-, deoxy-, met-, carboxy- and sulfhaemoglobin) is analysed numerically. The methods are proposed to determine in realtime these parameters without contact of the measuring instrument with the patient's body.

  14. Analysis of MODIS 250 m Time Series Product for LULC Classification and Retrieval of Crop Biophysical Parameter

    Science.gov (United States)

    Verma, A. K.; Garg, P. K.; Prasad, K. S. H.; Dadhwal, V. K.

    2016-12-01

    Agriculture is a backbone of Indian economy, providing livelihood to about 70% of the population. The primary objective of this research is to investigate the general applicability of time-series MODIS 250m Normalized difference vegetation index (NDVI) and Enhanced vegetation index (EVI) data for various Land use/Land cover (LULC) classification. The other objective is the retrieval of crop biophysical parameter using MODIS 250m resolution data. The Uttar Pradesh state of India is selected for this research work. A field study of 38 farms was conducted during entire crop season of the year 2015 to evaluate the applicability of MODIS 8-day, 250m resolution composite images for assessment of crop condition. The spectroradiometer is used for ground reflectance and the AccuPAR LP-80 Ceptometer is used to measure the agricultural crops Leaf Area Index (LAI). The AccuPAR measures Photosynthetically Active Radiation (PAR) and can invert these readings to give LAI for plant canopy. Ground-based canopy reflectance and LAI were used to calibrate a radiative transfer model to create look-up table (LUT) that was used to simulate LAI. The seasonal trend of MODIS-derived LAI was used to find crop parameter by adjusting the LAI simulated from climate-based crop yield model. Cloud free MODIS images of 250m resolution (16 day composite period) were downloaded using LP-DAAC website over a period of 12 months (Jan to Dec 2015). MODIS both the VI products were found to have sufficient spectral, spatial and temporal resolution to detect unique signatures for each class (water, fallow land, urban, dense vegetation, orchard, sugarcane and other crops). Ground truth data were collected using JUNO GPS. Multi-temporal VI signatures for vegetation classes were consistent with its general phenological characteristic and were spectrally separable at some point during the growing season. The MODIS NDVI and EVI multi-temporal images tracked similar seasonal responses for all croplands and were

  15. Evaluation of changes in skin biophysical parameters and appearance after pneumatic injections of non-cross-linked hyaluronic acid in the face.

    Science.gov (United States)

    Cheng, Hai-Yan; Chen, Yu-Xin; Wang, Mei-Fang; Zhao, Jun-Ying; Li, Lin-Feng

    2018-03-15

    Pneumatic injections of non-cross-linked hyaluronic acid are effective in skin rejuvenation, however, the associated biophysical parameters and appearance have not been evaluated. To determine the changes in skin biophysical parameters after facial pneumatic injections of non-cross-linked hyaluronic acid. Twenty-eight healthy female volunteers received pneumatic injections of non-cross-linked hyaluronic acid into the face for consecutive 5 weeks. Skin biophysical parameter assessment and clinical evaluation were performed using the CK Multi-Probe Adapter and Visia system. Five of the volunteers also underwent retroauricular skin biopsy before and after the last treatment. The skin tissues were all stained with Masson-trichrome, Verhoeff-van Gieson stain, and hematoxylin-eosin to evaluate the changes in collagen, elastic fibers, and the epidermis, before and after the last treatment. Transepidermal water loss was significantly lower in week 4 (18.46 ± 4.70 g/h/m 2 ) than at the baseline (22.03 ± 7.15 g/h/m 2 , p pores also improved significantly at week 4 (934.07 ± 458.78) compared to the baseline (1024.57 ± 415.31, p pores, and wrinkles.

  16. Incremental Closed-loop Identification of Linear Parameter Varying Systems

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2011-01-01

    , closed-loop system identification is more difficult than open-loop identification. In this paper we prove that the so-called Hansen Scheme, a technique known from linear time-invariant systems theory for transforming closed-loop system identification problems into open-loop-like problems, can be extended...

  17. Close visual binaries. III. Parameters and evolutionary status

    International Nuclear Information System (INIS)

    Corbally, C.J.

    1984-01-01

    New Yale isochrones, which have been tested for accuracy (Paper II), provide the means to investigate interesting visual binaries, especially those whose classifications and photometry do not match well (Paper I). Various parameters are deduced for those binaries which fitted the isochrones (e.g., ages, metal abundances, luminosities of peculiar stars); various solutions are systematically developed for those which did not fit, and a likely status of evolution proposed (e.g., duplicity of the components, pre-main-sequence, blue straggler, horizontal branch, optical pair, data inaccuracies). Evolution around the helium flash and diffusion theory are briefly considered. These parameters and statuses provide a wealth of new stellar data and suggestions for further investigation

  18. Close visual binaries. III. Parameters and evolutionary status

    Energy Technology Data Exchange (ETDEWEB)

    Corbally, C.J.

    1984-12-01

    New Yale isochrones, which have been tested for accuracy (Paper II), provide the means to investigate interesting visual binaries, especially those whose classifications and photometry do not match well (Paper I). Various parameters are deduced for those binaries which fitted the isochrones (e.g., ages, metal abundances, luminosities of peculiar stars); various solutions are systematically developed for those which did not fit, and a likely status of evolution proposed (e.g., duplicity of the components, pre-main-sequence, blue straggler, horizontal branch, optical pair, data inaccuracies). Evolution around the helium flash and diffusion theory are briefly considered. These parameters and statuses provide a wealth of new stellar data and suggestions for further investigation.

  19. Kinematic parameter estimation using close range photogrammetry for sport applications

    Science.gov (United States)

    Magre Colorado, Luz Alejandra; Martínez Santos, Juan Carlos

    2015-12-01

    In this article, we show the development of a low-cost hardware/software system based on close range photogrammetry to track the movement of a person performing weightlifting. The goal is to reduce the costs to the trainers and athletes dedicated to this sport when it comes to analyze the performance of the sportsman and avoid injuries or accidents. We used a web-cam as the data acquisition hardware and develop the software stack in Processing using the OpenCV library. Our algorithm extracts size, position, velocity, and acceleration measurements of the bar along the course of the exercise. We present detailed characteristics of the system with their results in a controlled setting. The current work improves the detection and tracking capabilities from a previous version of this system by using HSV color model instead of RGB. Preliminary results show that the system is able to profile the movement of the bar as well as determine the size, position, velocity, and acceleration values of a marker/target in scene. The average error finding the size of object at four meters of distance is less than 4%, and the error of the acceleration value is 1.01% in average.

  20. Mathematical biophysics

    CERN Document Server

    Rubin, Andrew

    2014-01-01

    This book presents concise descriptions and analysis of the classical and modern models used in mathematical biophysics. The authors ask the question "what new information can be provided by the models that cannot be obtained directly from experimental data?" Actively developing fields such as regulatory mechanisms in cells and subcellular systems and electron transport and energy transport in membranes are addressed together with more classical topics such as metabolic processes, nerve conduction and heart activity, chemical kinetics, population dynamics, and photosynthesis. The main approach is to describe biological processes using different mathematical approaches necessary to reveal characteristic features and properties of simulated systems. With the emergence of powerful mathematics software packages such as MAPLE, Mathematica, Mathcad, and MatLab, these methodologies are now accessible to a wide audience. Provides succinct but authoritative coverage of a broad array of biophysical topics and models Wr...

  1. The effect of halogen light stimulation on duration of ultrasound parameters of biophysical profile: a randomized clinical trial.

    Science.gov (United States)

    Hanafi, Mohammad Ghasem; Sahraeizadeh, Aliakbar

    2018-02-22

    The objective is to assess if fetal halogen light stimulation can reduce the time needed to obtain a normal biophysical profile (BPP). Patients scheduled for a BPP and who satisfied the inclusion criteria were prospectively randomized to halogen light stimulation and no stimulation groups. The study group was exposed to handheld halogen light for 10 s whenever fetal breathing, movement, or tone was absent through the first 5 min of BPP. The time required to achieve complete BPP score was recorded. In patients with complete BPP score who had delivery within 1 week after the test, perinatal morbidity was examined. A total of 598 patients were randomized (light = 302, no light = 296). There was no difference between the two groups in terms of gestational age, maternal age, body mass index, and indication for BPP except for preterm labor (light: 9%, no light: 4%, p = 0.03). Among the patients who had a normal BPP score (n = 507), the mean (light: 7.1 ± 6 min, no light: 12.3 ± 8 min, p BPP score was significantly less in the light stimulation group than the no stimulation group. Perinatal outcomes were not different between groups who had delivery during the first week after BPP. Fetal halogen light stimulation can be utilized to reduce the time needed to complete a BPP. However, further studies should be conducted in order to determine the effect of this method on decreasing non-reassuring test results. The study was submitted to the Registry of Clinical Trials on 04/20/2017 (IRCT2017041633470N1). After IRCT registration on 06/07/2017, we recruited patients from 06/08/2017 till 10/15/2017.

  2. Structural biophysics

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    Summaries of research projects conducted during 1978 and 1979 are presented. The structural biophysics group explores the high-resolution structure of biological macromolecules and cell organelles. Specific subject areas include: the basic characteristics of photosynthesis in plants; the chemical composition of individual fly ash particles at the site of their damaging action in tissues; direct analysis of frozen-hydrated biological samples by scanning electron microscopy; yeast genetics; the optical activity of DNA aggregates; measurement and characterization of lipoproteins; function of lipoproteins; and the effect of radiation and pollutants on mammalian cells

  3. Modulating effects of bioactive water Naftussya from layers Truskavets’ and Pomyarky on some metabolic and biophysic parameters at humans with dysfunction of neuro-endocrine-immune complex

    Directory of Open Access Journals (Sweden)

    Anatoliy I Gozhenko

    2016-12-01

    Full Text Available Background. Previously we have been carry out comparative investigation immediate effects of Bioactive Water Naftussya from layers Truskavets’, Pomyarky and Skhidnyts’a on neuro-endocrine-immune complex at men with its dysfunction. The aim of this study is the influence of the use of the course of Bioactive Water Naftussya from layers Truskavets’ and Pomyarky on some metabolic and biophysical parameters at similar patients. Materials and methods. The object of observation were 20 volunteers: ten women and ten men aged 33-76 years without clinical diagnose but with dysfunction of neuro-endocrine-immune complex and metabolism. In daily urine and venous blood we determined the content of electrolytes, nitrogenous metabolites and lipids, recorded conductivity of acupuncture points, rate of electronegative nuclei of buccal epithelium as well as parameters of gas discharge vizualisation (GDV. After examination volunteers within 7 days used bioactive water Naftussya (250 mL three times a day from Truskavets’ or Pomyarky layer, then repeated the tests listed. Results. Weekly use of Bioactive Water Naftussya increases in the normal level of plasma chloride and sodium, normalizes low level of bicarbonate and decreases within the normal levels of potassium and phosphate. Urinary excretion of sodium and chloride increases while excretion and concentration of uric acid decreases, as the urine concentration of phosphates. The index lithogenicity urine decreased from 112% to 103% norm standard. Initially reduced level of plasma triacylglycerides increases, while decreases in the normal level of cholesterol in low-density lipoprotein composition. Among the biophysical parameters detected increase in the normal conductivity acupuncture points Pg (ND at right side, which represent the nervous system, and left shift the ratio between the conductivity of acupuncture points MC (AVL, which represents the immune system. Increases electrokinetic index of

  4. Radiation biophysics

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    Summaries of research projects conducted during 1978 and 1979 are presented. The overall thrust of the research is aimed at understanding the effects of radiation on organisms. Specific subject areas include: the effects of heavy-particle beam nuclear interactions in tissue on dosimetry; tracer studies with radioactive fragments of heavy-ion beams; the effects of heavy/ions on human kidney cells and Chinese hamster cells; the response of a rhabdomyosarcoma tumor system in rats to heavy-ion beams; the use of heavy charged particles in radiotherapy of human cancer; heavy-ion radiography; the biological effects of high magnetic fields; central nervous system neurotoxicity; and biophysical studies on cell membranes

  5. Sensitivity of a carbon and productivity model to climatic, water, terrain, and biophysical parameters in a Rocky Mountain watershed

    Energy Technology Data Exchange (ETDEWEB)

    Xu, S.; Peddle, D.R.; Coburn, C.A.; Kienzle, S. [Univ. of Lethbridge, Dept. of Geography, Lethbridge, Alberta (Canada)

    2008-06-15

    Net primary productivity (NPP) is a key component of the terrestrial carbon cycle and is important in ecological, watershed, and forest management studies, and more broadly in global climate change research. Determining the relative importance and magnitude of uncertainty of NPP model inputs is important for proper carbon reporting over larger areas and time periods. This paper presents a systematic evaluation of the boreal ecosystem productivity simulator (BEPS) model in mountainous terrain using an established montane forest test site in Kananaskis, Alberta, in the Canadian Rocky Mountains. Model runs were based on forest (land cover, leaf area index (LAI), biomass) and climate-water inputs (solar radiation, temperature, precipitation, humidity, soil water holding capacity) derived from digital elevation model (DEM) derivatives, climate data, geographical information system (GIS) functions, and topographically corrected satellite imagery. Four sensitivity analyses were conducted as a controlled series of experiments involving (i) NPP individual parameter sensitivity for a full growing season, (ii) NPP independent variation tests (parameter {mu} {+-} 1{sigma}), (iii) factorial analyses to assess more complex multiple-factor interactions, and (iv) topographic correction. The results, validated against field measurements, showed that modeled NPP was sensitive to most inputs measured in the study area, with LAI and forest type the most important forest input, and solar radiation the most important climate input. Soil available water holding capacity expressed as a function of wetness index was only significant in conjunction with precipitation when both parameters represented a moisture-deficit situation. NPP uncertainty resulting from topographic influence was equivalent to 140 kg C ha{sup -1}{center_dot}year{sup -1}. This suggested that topographic correction of model inputs is important for accurate NPP estimation. The BEPS model, designed originally for flat

  6. Sensitivity of a carbon and productivity model to climatic, water, terrain, and biophysical parameters in a Rocky Mountain watershed

    International Nuclear Information System (INIS)

    Xu, S.; Peddle, D.R.; Coburn, C.A.; Kienzle, S.

    2008-01-01

    Net primary productivity (NPP) is a key component of the terrestrial carbon cycle and is important in ecological, watershed, and forest management studies, and more broadly in global climate change research. Determining the relative importance and magnitude of uncertainty of NPP model inputs is important for proper carbon reporting over larger areas and time periods. This paper presents a systematic evaluation of the boreal ecosystem productivity simulator (BEPS) model in mountainous terrain using an established montane forest test site in Kananaskis, Alberta, in the Canadian Rocky Mountains. Model runs were based on forest (land cover, leaf area index (LAI), biomass) and climate-water inputs (solar radiation, temperature, precipitation, humidity, soil water holding capacity) derived from digital elevation model (DEM) derivatives, climate data, geographical information system (GIS) functions, and topographically corrected satellite imagery. Four sensitivity analyses were conducted as a controlled series of experiments involving (i) NPP individual parameter sensitivity for a full growing season, (ii) NPP independent variation tests (parameter μ ± 1σ), (iii) factorial analyses to assess more complex multiple-factor interactions, and (iv) topographic correction. The results, validated against field measurements, showed that modeled NPP was sensitive to most inputs measured in the study area, with LAI and forest type the most important forest input, and solar radiation the most important climate input. Soil available water holding capacity expressed as a function of wetness index was only significant in conjunction with precipitation when both parameters represented a moisture-deficit situation. NPP uncertainty resulting from topographic influence was equivalent to 140 kg C ha -1 ·year -1 . This suggested that topographic correction of model inputs is important for accurate NPP estimation. The BEPS model, designed originally for flat boreal forests, was shown to be

  7. Biophysical radiosensitization

    International Nuclear Information System (INIS)

    Vladescu, C.; Apetroae, M.

    1983-01-01

    Experimental studies on normal and tumor-bearing rats revealed that chronic treatment with hydroquinone (5 mg/kg/day) inhibited catalase activity in liver, spleen, blood, and H 18R tumor. 3 H-hydroquinone (1.5 μCi/g body weight) showed tumor specificity, with maximum radioactivity in the tumor at 1 h after administration. The biological half-time of 3 H-hydroquinone in the tumor was 2 h, but there seems to exist a longer component, since 24 h after administration, some 30% of the maximum radioactivity could be detected in the tumor. Hydroquinone treatment produces a specific inhibition of catalase in the tumor and a higher degree of oxygenation at this level. These findings support the assumption that the mechanism of action of hydroquinone as an anticancer agent is achieved mainly via peroxide production. The oxygenation of the hypoxic tumoral tissue is done at non-toxic levels of hydroquinone, through a natural and specific biophysical pathway, recommanding hydroquinone for combined anticancer treatment (radiotherapy and chemotherapy). (orig.)

  8. Model Optimization Identification Method Based on Closed-loop Operation Data and Process Characteristics Parameters

    Directory of Open Access Journals (Sweden)

    Zhiqiang GENG

    2014-01-01

    Full Text Available Output noise is strongly related to input in closed-loop control system, which makes model identification of closed-loop difficult, even unidentified in practice. The forward channel model is chosen to isolate disturbance from the output noise to input, and identified by optimization the dynamic characteristics of the process based on closed-loop operation data. The characteristics parameters of the process, such as dead time and time constant, are calculated and estimated based on the PI/PID controller parameters and closed-loop process input/output data. And those characteristics parameters are adopted to define the search space of the optimization identification algorithm. PSO-SQP optimization algorithm is applied to integrate the global search ability of PSO with the local search ability of SQP to identify the model parameters of forward channel. The validity of proposed method has been verified by the simulation. The practicability is checked with the PI/PID controller parameter turning based on identified forward channel model.

  9. Parameter Estimation of a Closed Loop Coupled Tank Time Varying System using Recursive Methods

    International Nuclear Information System (INIS)

    Basir, Siti Nora; Yussof, Hanafiah; Shamsuddin, Syamimi; Selamat, Hazlina; Zahari, Nur Ismarrubie

    2013-01-01

    This project investigates the direct identification of closed loop plant using discrete-time approach. The uses of Recursive Least Squares (RLS), Recursive Instrumental Variable (RIV) and Recursive Instrumental Variable with Centre-Of-Triangle (RIV + COT) in the parameter estimation of closed loop time varying system have been considered. The algorithms were applied in a coupled tank system that employs covariance resetting technique where the time of parameter changes occur is unknown. The performances of all the parameter estimation methods, RLS, RIV and RIV + COT were compared. The estimation of the system whose output was corrupted with white and coloured noises were investigated. Covariance resetting technique successfully executed when the parameters change. RIV + COT gives better estimates than RLS and RIV in terms of convergence and maximum overshoot

  10. In vivo evaluation of some biophysical parameters of the facial skin of Indian subjects living in Mumbai. Part II: Variability with age and gender.

    Science.gov (United States)

    Colomb, L; Flament, F; Wagle, A; Idelcaid, Y; Agrawal, D

    2018-04-01

    A previously published work explored the diversity of some biophysical parameters (colour, elasticity, sebum production, skin microrelief, etc.) of the skin of 1204 Indian women, differently aged, living in four Indian cities (Chennai, Delhi, Kolkata and Mumbai). The present work aimed at completing such research by focusing on possible gender-related differences in the same skin parameters, between Indian men and women living in the same Indian city (Mumbai). A total of 297 Indian men, differently aged (18-70y), were recruited in Mumbai, completing the panel of 303 women who were previously recruited in this same city. The same instrumental measurements of facial skin colour and its homogeneity, its mechanical properties, the sebum production, skin pores size, skin relief, etc. as in the previous work, were conducted. Overall, the facial skin colour shows a darker complexion in men as compared to women, on forehead, ocular region, lips, chin and cheek. The skin colour unevenness, which increases with age, was found higher in men, as compared to women. At comparable age, women and men present a same density of skin pores, whereas those of men appear larger, up to 55y. The deepness of Crow's feet wrinkles does not significantly differ between genders. A lesser extensibility was found on the cheeks of men. In men, the sebum production was found significantly higher than that of women at ages above 40y. This work indicates some commonly shared age-related skin features between women and men from Mumbai, despite slight different characteristics such as skin pigmentation, forehead/cheek colour contrast, mechanical properties and sebum production. © 2018 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  11. Parameter masks for close talk speech segregation using deep neural networks

    Directory of Open Access Journals (Sweden)

    Jiang Yi

    2015-01-01

    Full Text Available A deep neural networks (DNN based close talk speech segregation algorithm is introduced. One nearby microphone is used to collect the target speech as close talk indicated, and another microphone is used to get the noise in environments. The time and energy difference between the two microphones signal is used as the segregation cue. A DNN estimator on each frequency channel is used to calculate the parameter masks. The parameter masks represent the target speech energy in each time frequency (T-F units. Experiment results show the good performance of the proposed system. The signal to noise ratio (SNR improvement is 8.1 dB on 0 dB noisy environment.

  12. Classification of high-resolution multi-swath hyperspectral data using Landsat 8 surface reflectance data as a calibration target and a novel histogram based unsupervised classification technique to determine natural classes from biophysically relevant fit parameters

    Science.gov (United States)

    McCann, C.; Repasky, K. S.; Morin, M.; Lawrence, R. L.; Powell, S. L.

    2016-12-01

    Compact, cost-effective, flight-based hyperspectral imaging systems can provide scientifically relevant data over large areas for a variety of applications such as ecosystem studies, precision agriculture, and land management. To fully realize this capability, unsupervised classification techniques based on radiometrically-calibrated data that cluster based on biophysical similarity rather than simply spectral similarity are needed. An automated technique to produce high-resolution, large-area, radiometrically-calibrated hyperspectral data sets based on the Landsat surface reflectance data product as a calibration target was developed and applied to three subsequent years of data covering approximately 1850 hectares. The radiometrically-calibrated data allows inter-comparison of the temporal series. Advantages of the radiometric calibration technique include the need for minimal site access, no ancillary instrumentation, and automated processing. Fitting the reflectance spectra of each pixel using a set of biophysically relevant basis functions reduces the data from 80 spectral bands to 9 parameters providing noise reduction and data compression. Examination of histograms of these parameters allows for determination of natural splitting into biophysical similar clusters. This method creates clusters that are similar in terms of biophysical parameters, not simply spectral proximity. Furthermore, this method can be applied to other data sets, such as urban scenes, by developing other physically meaningful basis functions. The ability to use hyperspectral imaging for a variety of important applications requires the development of data processing techniques that can be automated. The radiometric-calibration combined with the histogram based unsupervised classification technique presented here provide one potential avenue for managing big-data associated with hyperspectral imaging.

  13. 2. biophysical work meeting

    International Nuclear Information System (INIS)

    1992-11-01

    The report comprises 18 papers held at the 2nd Biophysical Work Meeting, 11 - 13 September 1991 in Schlema, Germany. The history of biophysics in Germany particularly of radiation biophysics and radon research, measurements of the radiation effects of radon and the derivation of limits, radon balneotherapy and consequences of uranium ore mining are dealt with. (orig.) [de

  14. Biophysics conference 1978

    International Nuclear Information System (INIS)

    1978-01-01

    The main subject on the biophysics meeting was the biophysics of membranes with practical subjects from photosynthesis and the transfer processes on membranes. In radiation biophysics, problems of radiation sensitisation, immunological problems after radiation exposure, the oxygen effect and inhibitory processes in RNS synthesis after radiation exposure were discussed with a view to tumour therapy. (AJ) [de

  15. Closed-form kinetic parameter estimation solution to the truncated data problem

    International Nuclear Information System (INIS)

    Zeng, Gengsheng L; Kadrmas, Dan J; Gullberg, Grant T

    2010-01-01

    In a dedicated cardiac single photon emission computed tomography (SPECT) system, the detectors are focused on the heart and the background is truncated in the projections. Reconstruction using truncated data results in biased images, leading to inaccurate kinetic parameter estimates. This paper has developed a closed-form kinetic parameter estimation solution to the dynamic emission imaging problem. This solution is insensitive to the bias in the reconstructed images that is caused by the projection data truncation. This paper introduces two new ideas: (1) it includes background bias as an additional parameter to estimate, and (2) it presents a closed-form solution for compartment models. The method is based on the following two assumptions: (i) the amount of the bias is directly proportional to the truncated activities in the projection data, and (ii) the background concentration is directly proportional to the concentration in the myocardium. In other words, the method assumes that the image slice contains only the heart and the background, without other organs, that the heart is not truncated, and that the background radioactivity is directly proportional to the radioactivity in the blood pool. As long as the background activity can be modeled, the proposed method is applicable regardless of the number of compartments in the model. For simplicity, the proposed method is presented and verified using a single compartment model with computer simulations using both noiseless and noisy projections.

  16. Evaluation of Experimental Parameters in the Accelerated Aging of Closed-Cell Foam Insulation

    Energy Technology Data Exchange (ETDEWEB)

    Stovall, Therese K [ORNL; Vanderlan, Michael [ORNL; Atchley, Jerald Allen [ORNL

    2012-12-01

    The thermal conductivity of many closed-cell foam insulation products changes over time as production gases diffuse out of the cell matrix and atmospheric gases diffuse into the cells. Thin slicing has been shown to be an effective means of accelerating this process in such a way as to produce meaningful results. Efforts to produce a more prescriptive version of the ASTM C1303 standard test method led to the ruggedness test described here. This test program included the aging of full size insulation specimens for time periods of five years for direct comparison to the predicted results. Experimental parameters under investigation include: slice thickness, slice origin (at the surface or from the core of the slab), thin slice stack composition, product facings, original product thickness, product density, and product type. The test protocol has been completed and this report provides a detailed evaluation of the impact of the test parameters on the accuracy of the 5-year thermal conductivity prediction.

  17. Closed-Loop Dynamic Parameter Identification of Robot Manipulators Using Modified Fourier Series

    Directory of Open Access Journals (Sweden)

    Wenxiang Wu

    2012-05-01

    Full Text Available This paper concerns the problem of dynamic parameter identification of robot manipulators and proposes a closed-loop identification procedure using modified Fourier series (MFS as exciting trajectories. First, a static continuous friction model is involved to model joint friction for realizable friction compensation in controller design. Second, MFS satisfying the boundary conditions are firstly designed as periodic exciting trajectories. To minimize the sensitivity to measurement noise, the coefficients of MFS are optimized according to the condition number criterion. Moreover, to obtain accurate parameter estimates, the maximum likelihood estimation (MLE method considering the influence of measurement noise is adopted. The proposed identification procedure has been implemented on the first three axes of the QIANJIANG-I 6-DOF robot manipulator. Experiment results verify the effectiveness of the proposed approach, and comparison between identification using MFS and that using finite Fourier series (FFS reveals that the proposed method achieves better identification accuracy.

  18. Biophysics of radiation action

    International Nuclear Information System (INIS)

    Dertinger, H.

    1984-01-01

    Understanding the cellular response to ionizing radiation is not only necessary to meet the requirements of radioprotection, but also for medical application of radiation in cancer treatment. In terms of radiobiology, cancer therapy means the selective inactivation of malignant cells without affecting the normal healthy tissue. However, for several physical and biological reasons, this ideal situation is normally not attained. The elaboration of biophysical parameters that could be used to improve the selective sterilization of tumor cells has become one of the main activities of cellular radiobiology during the last two decades. Progress in this field has been facilitated by the development of tissue culture techniques allowing to grow and analyze cells in a synthetic nutrient medium. This chapter describes the physical and biological factors which determine cellular radiosensitivity and which are important to know for better understanding the cellular radiation action, in particular with reference to cancer treatment

  19. Methods in Modern Biophysics

    CERN Document Server

    Nölting, Bengt

    2006-01-01

    Incorporating recent dramatic advances, this textbook presents a fresh and timely introduction to modern biophysical methods. An array of new, faster and higher-power biophysical methods now enables scientists to examine the mysteries of life at a molecular level. This innovative text surveys and explains the ten key biophysical methods, including those related to biophysical nanotechnology, scanning probe microscopy, X-ray crystallography, ion mobility spectrometry, mass spectrometry, proteomics, and protein folding and structure. Incorporating much information previously unavailable in tutorial form, Nölting employs worked examples and 267 illustrations to fully detail the techniques and their underlying mechanisms. Methods in Modern Biophysics is written for advanced undergraduate and graduate students, postdocs, researchers, lecturers and professors in biophysics, biochemistry and related fields. Special features in the 2nd edition: • Illustrates the high-resolution methods for ultrashort-living protei...

  20. Methods in Modern Biophysics

    CERN Document Server

    Nölting, Bengt

    2010-01-01

    Incorporating recent dramatic advances, this textbook presents a fresh and timely introduction to modern biophysical methods. An array of new, faster and higher-power biophysical methods now enables scientists to examine the mysteries of life at a molecular level. This innovative text surveys and explains the ten key biophysical methods, including those related to biophysical nanotechnology, scanning probe microscopy, X-ray crystallography, ion mobility spectrometry, mass spectrometry, proteomics, and protein folding and structure. Incorporating much information previously unavailable in tutorial form, Nölting employs worked examples and about 270 illustrations to fully detail the techniques and their underlying mechanisms. Methods in Modern Biophysics is written for advanced undergraduate and graduate students, postdocs, researchers, lecturers, and professors in biophysics, biochemistry and related fields. Special features in the 3rd edition: Introduces rapid partial protein ladder sequencing - an important...

  1. New horizons in Biophysics

    Science.gov (United States)

    2011-01-01

    This editorial celebrates the re-launch of PMC Biophysics previously published by PhysMath Central, in its new format as BMC Biophysics published by BioMed Central with an expanded scope and Editorial Board. BMC Biophysics will fill its own niche in the BMC series alongside complementary companion journals including BMC Bioinformatics, BMC Medical Physics, BMC Structural Biology and BMC Systems Biology. PMID:21595996

  2. Very-low speed control of PMSM based on EKF estimation with closed loop optimized parameters.

    Science.gov (United States)

    Xu, Dong; Zhang, Shaoguang; Liu, Jingmeng

    2013-11-01

    When calculating the speed from the position of permanent magnet synchronous motor (PMSM), the accuracy and real-time are limited by the precision of the sensor. This problem causes crawling and jitter at very-low speed. Using the angle from the position sensor, an extended Kalman filter (EKF) designed in dq-coordinate is presented to solve this problem. The usage of position sensor simplifies the model and improves the accuracy of speed estimation. Specially, a closed loop optimal (CLO) method is devised to overcome the difficulty to adjust the parameters of the EKF. The EKF is the feedback link of speed control, CLO method is derived from the perspective of the speed step response to optimize the measurement covariance matrix and the system covariance matrix of EKF. Simulation and experimental results, comparing the low-speed performance of the EKF and sensor feedback methods, prove the effectiveness of the method to adjust the parameters of EKF and the advantages in eliminating the low speed jitter. © 2013 ISA. Published by ISA. All rights reserved.

  3. Clinical and instrumental evaluation of a cross-linked hyaluronic acid filler dermal injection: effects on nasolabial folds skin biophysical parameters and augmentation from a single-dose, monocentric, open-label trial.

    Science.gov (United States)

    Cameli, Norma; Mariano, Maria; Serio, Mirko; Berardesca, Enzo

    2016-10-01

    When a hyaluronic acid dermal device to fill soft tissues is chosen, efficacy, safety and durability are key concerns. This is an open-label prospective study to instrumentally evaluate the effects of HA filler dermal injection on nasolabial folds skin biophysical parameters and augmentation. A single Italian site treated female subjects aged 40-55, for nasolabial folds, with a single standardized injection. The outcome was evaluated with objective quantitative measurements after 90 (T1) and 180 days (T2) from the injection comparing to baseline (T0) by means of Corneometer (skin hydration measurement), Cutometer (skin elasticity measurement), and Visioface devices for digital and UV computerized image analysis. Secondary endpoints were safety assessment, subject investigator satisfaction with the intervention. Assessment of aesthetic results included photographic documentation. The computerized image analysis confirmed the clinical assessment showing statistically significant reduction in nasolabial folds both at T1 and T2. Visioface® indexes showed a marked and statistical significant response. An excellent profile of satisfaction of the product at T2 from investigators and patients was recorded. Skin hydration and elasticity did not show significant changes. In our study, a standardized HA filler dermal injection on nasolabial folds did not influence skin biophysical parameters such as skin hydration and elasticity. Nasolabial folds showed a persistent and significative response at T2 confirmed by instrumental evaluation. The tolerability and safety profile of the product was excellent.

  4. Cognitive functioning is more closely related to real-life mobility than to laboratory-based mobility parameters

    NARCIS (Netherlands)

    Giannouli, Eleftheria; Bock, Otmar; Zijlstra, Wiebren

    2018-01-01

    Increasing evidence indicates that mobility depends on cognitive resources, but the exact relationships between various cognitive functions and different mobility parameters still need to be investigated. This study examines the hypothesis that cognitive functioning is more closely related to

  5. Biophysics An Introduction

    CERN Document Server

    Glaser, Roland

    2012-01-01

    Biophysics is the science of physical principles underlying all processes of life, including the dynamics and kinetics of biological systems. This fully revised 2nd English edition is an introductory text that spans all steps of biological organization, from the molecular, to the organism level, as well as influences of environmental factors. In response to the enormous progress recently made, especially in theoretical and molecular biophysics, the author has updated the text, integrating new results and developments concerning protein folding and dynamics, molecular aspects of membrane assembly and transport, noise-enhanced processes, and photo-biophysics. The advances made in theoretical biology in the last decade call for a fully new conception of the corresponding sections. Thus, the book provides the background needed for fundamental training in biophysics and, in addition, offers a great deal of advanced biophysical knowledge.

  6. Effect of closed shells on the multipole mixing parameter δ(E2/M1)

    International Nuclear Information System (INIS)

    Morozov, V.A.

    1992-01-01

    The behavior of the magnitude and sign of the mixing parameter δ(E2/M1) in even-even nuclei has been studied in a number of papers. The most extensive data has been given for transitions of the type 3 γ + , 2 γ + , 2 β + →2 g + . The data on δ are relatively scarce for mixed transitions in odd nuclei with magic or semimagic cores. However, certain conclusions can be drawn about the behavior of δ in transitions in odd nuclei near magic numbers, and also in transitions in even-even nuclei when passing through quasishells: (1) the absolute value of the reduced mixing parameter in transitions between particle and cluster-vibrational states in odd nuclei decreases as a closed shell is approached; (2) δ has the same sign for transitions between particle and cluster-vibrational levels in nuclei with Z=83 and 85 and N=83, 85, and 87; (3) in odd nuclei the sign of δ is positive for transitions between positive-parity states s 1/2 -d 3/2 in Cd, Sm, and Tl isotopes and is negative for transitions between negative-parity states f 7/2 π and h 9/2 π in Sm, Gd, Bi, and At isotopes, independently of whether these transitions are neutron or proton transitions; (4) the removal of ±2 nucleons in an even shell from a magic core (and in certain nuclei a larger number of pairs of nucleons) does not lead to a change in sign of δ in transitions producing an odd nucleus; (5) the closure of quasishells at N=96 and 104 in even-even nuclei is associated with an increase in the absolute value of δ(E2/M1)/E γ , but the sign of δ does not change

  7. Advanced Techniques in Biophysics

    CERN Document Server

    Arrondo, José Luis R

    2006-01-01

    Technical advancements are basic elements in our life. In biophysical studies, new applications and improvements in well-established techniques are being implemented every day. This book deals with advancements produced not only from a technical point of view, but also from new approaches that are being taken in the study of biophysical samples, such as nanotechniques or single-cell measurements. This book constitutes a privileged observatory for reviewing novel applications of biophysical techniques that can help the reader enter an area where the technology is progressing quickly and where a comprehensive explanation is not always to be found.

  8. Encyclopedia of biophysics

    CERN Document Server

    2013-01-01

    The Encyclopedia of Biophysics is envisioned both as an easily accessible source of information and as an introductory guide to the scientific literature. It includes entries describing both Techniques and Systems.  In the Techniques entries, each of the wide range of methods which fall under the heading of Biophysics are explained in detail, together with the value and the limitations of the information each provides. Techniques covered range from diffraction (X-ray, electron and neutron) through a wide range of spectroscopic methods (X-ray, optical, EPR, NMR) to imaging (from electron microscopy to live cell imaging and MRI), as well as computational and simulation approaches. In the Systems entries, biophysical approaches to specific biological systems or problems – from protein and nucleic acid structure to membranes, ion channels and receptors – are described. These sections, which place emphasis on the integration of the different techniques, therefore provide an inroad into Biophysics from a biolo...

  9. In vivo evaluation of some biophysical parameters of the facial skin of Indian women. Part I: variability with age and geographical locations.

    Science.gov (United States)

    Colomb, L; Flament, F; Wagle, A; Agrawal, D

    2018-02-01

    India is a large country (a subcontinent) of about 3.3 million km 2 that covers large ranges in latitude and longitude. The last Indian census counted about 1.21 billion of inhabitants of many origins, creating a vast human diversity and skin types, the variability of which having been previously established. The present study aimed at deepening this knowledge through a set of biophysical measurements to describe, along the skin ageing process, the specificities of various Indian subjects living in different geographical locations. A total of 1204 women, aged 18-84 years, of all socio-economic status, were recruited in four Indian cities (Mumbai, Kolkata, Chennai and Delhi). Measurements of face skin colour properties, elastic properties, sebum production, skin pores and microrelief roughness were performed. With regard skin colour, this study indicates, with age, a darkening of very low amplitude that leads to an increased skin colour heterogeneity. In all subjects, at all ages, the ocular region (dark circles) presents a much darker pigmentation than the cheeks, creating a contrast that appears constant at all ages. In addition to an increased skin colour heterogeneity, a progressive alteration of the skin surface relief, increased sizes of skin pores, a loss of skin elasticity and a drop in sebum production, post-menopause, are observed. This study confirms, in Indian women, some skin ageing measurements found on women from other ethnic groups (i.e. sebum, firmness, wrinkles and pores size) and also identifies some Indian specificities: a high and constant contrast between the ocular region and the cheek colour, associated to a very slow darkening effect along the lifespan. © 2017 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  10. The estimation of soil parameters using observations on crop biophysical variables and the crop model STICS improve the predictions of agro environmental variables.

    Science.gov (United States)

    Varella, H.-V.

    2009-04-01

    Dynamic crop models are very useful to predict the behavior of crops in their environment and are widely used in a lot of agro-environmental work. These models have many parameters and their spatial application require a good knowledge of these parameters, especially of the soil parameters. These parameters can be estimated from soil analysis at different points but this is very costly and requires a lot of experimental work. Nevertheless, observations on crops provided by new techniques like remote sensing or yield monitoring, is a possibility for estimating soil parameters through the inversion of crop models. In this work, the STICS crop model is studied for the wheat and the sugar beet and it includes more than 200 parameters. After a previous work based on a large experimental database for calibrate parameters related to the characteristics of the crop, a global sensitivity analysis of the observed variables (leaf area index LAI and absorbed nitrogen QN provided by remote sensing data, and yield at harvest provided by yield monitoring) to the soil parameters is made, in order to determine which of them have to be estimated. This study was made in different climatic and agronomic conditions and it reveals that 7 soil parameters (4 related to the water and 3 related to the nitrogen) have a clearly influence on the variance of the observed variables and have to be therefore estimated. For estimating these 7 soil parameters, a Bayesian data assimilation method is chosen (because of available prior information on these parameters) named Importance Sampling by using observations, on wheat and sugar beet crop, of LAI and QN at various dates and yield at harvest acquired on different climatic and agronomic conditions. The quality of parameter estimation is then determined by comparing the result of parameter estimation with only prior information and the result with the posterior information provided by the Bayesian data assimilation method. The result of the

  11. Closed-loop Identification for Control of Linear Parameter Varying Systems

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2014-01-01

    , closed- loop system identification is more difficult than open-loop identification. In this paper we prove that the so-called Hansen Scheme, a technique known from linear time-invariant systems theory for transforming closed-loop system identification problems into open-loop-like problems, can...

  12. Closed form formula for the exchange integrals in the impact-parameter treatment of heavy-particle collisions

    International Nuclear Information System (INIS)

    Kocbach, Ladislav; Liska, Richard

    1994-01-01

    The three-dimensional exchange integrals in the impact-parameter treatment of heavy particle collisions can be transformed to one-dimensional integrals over finite range. The closed form formula for the integrands of these one-dimensional integrals is derived. (Author)

  13. Combining vegetation index and model inversion methods for theextraction of key vegetation biophysical parameters using Terra and Aqua MODIS reflectance data

    DEFF Research Database (Denmark)

    Houborg, Rasmus Møller; Søgaard, Henrik; Bøgh, Eva

    2007-01-01

    for the inversion of a canopy reflectance model using Terra and Aqua MODIS multi-spectral, multi-temporal, and multi-angle reflectance observations to aid the determination of vegetation-specific physiological and structural canopy parameters. Land cover and site-specific inversion modeling was applied...

  14. Foam application from a closed system – a study of machine and foam parameters

    NARCIS (Netherlands)

    Lemmen, Jacques T.E.; Groot Wassink, Jan

    1990-01-01

    An attempt has been made to gain a greater insight into the interaction between foam and a moving textile substrate. The effects of changing wet pick–up, fabric velocity, liquid viscosity, foam density and mode of application on penetration have been studied. Application from a closed system makes

  15. Recent progress in Biophysics

    International Nuclear Information System (INIS)

    Bemski, G.

    1980-03-01

    Recent progress in biophysics is reviewed, and three examples of the use of physical techniques and ideas in biological research are given. The first one deals with the oxygen transporting protein-hemoglobin, the second one with photosynthesis, and the third one with image formation, using nuclear magnetic resonance. (Author) [pt

  16. Biophysics of molecular gastronomy.

    Science.gov (United States)

    Brenner, Michael P; Sörensen, Pia M

    2015-03-26

    Chefs and scientists exploring biophysical processes have given rise to molecular gastronomy. In this Commentary, we describe how a scientific understanding of recipes and techniques facilitates the development of new textures and expands the flavor palette. The new dishes that result engage our senses in unexpected ways. PAPERCLIP. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Biophysical Cancer Transformation Pathway

    Czech Academy of Sciences Publication Activity Database

    Pokorný, Jiří

    2009-01-01

    Roč. 28, č. 2 (2009), s. 105-123 ISSN 1536-8378 Institutional research plan: CEZ:AV0Z20670512 Keywords : Biophysics * Cancer * Electromagnetic fields Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.729, year: 2009

  18. Research Institute for Medical Biophysics

    International Nuclear Information System (INIS)

    Wynchank, S.

    1989-01-01

    The effects of ionising and non-ionising radiation on rodent tumours and normal tissue were studied in terms of cellular repair and the relevant biochemical and biophysical changes following radiation. Rodent tumours investigated in vivo were the CaNT adenocarcinoma and a chemically induced transplantable rhabdomyosarcoma. Radiations used were 100KVp of X-Rays, neutron beams, various magnetic fields, and microwave radiation of 2450MHz. The biochemical parameters measured were, inter alia, levels of adenosine-5'-triphoshate (ATP) and the specific activity of hexokinase (HK). Metabolic changes in ATP levels and the activity of HK were observed in tumour and normal tissues following ionising and non-ionising radiation in normoxia and hypoxia. The observation that the effect of radiation and chemotherapeutic treatment of some tumours may be size dependent can possibly now be explained by the variation of ATP content with tumour size. The enhanced tumour HK specific activity implies increased metabolism, possibly a consequence of cellular requirements to maintain homeostasis during repair processes. Other research projects of the Research Institute for Medical Biophysics involved, inter alia, gastroesophageal scintigraphies to evaluate the results of new forms of therapy. 1 ill

  19. Biophysical aspects of photodynamic therapy.

    Science.gov (United States)

    Juzeniene, Asta; Nielsen, Kristian Pagh; Moan, Johan

    2006-01-01

    Over the last three decades photodynamic therapy (PDT) has been developed to a useful clinical tool, a viable alternative in the treatment of cancer and other diseases. Several disciplines have contributed to this development: chemistry in the development of new photosensitizing agents, biology in the elucidation of cellular processes involved in PDT, pharmacology and physiology in identifying the mechanisms of distribution of photosensitizers in an organism, and, last but not least, physics in the development of better light sources, dosimetric concepts and construction of imaging devices, optical sensors and spectroscopic methods for determining sensitizer concentrations in different tissues. Physics and biophysics have also helped to focus on the role of pH for sensitizer accumulation, dose rate effects, oxygen depletion, temperature, and optical penetration of light of different wavelengths into various types of tissue. These are all important parameters for optimally effective PDT. The present review will give a brief, physically based, overview of PDT and then discuss some of the main biophysical aspects of this therapeutic modality.

  20. Theoretical Molecular Biophysics

    CERN Document Server

    Scherer, Philipp

    2010-01-01

    "Theoretical Molecular Biophysics" is an advanced study book for students, shortly before or after completing undergraduate studies, in physics, chemistry or biology. It provides the tools for an understanding of elementary processes in biology, such as photosynthesis on a molecular level. A basic knowledge in mechanics, electrostatics, quantum theory and statistical physics is desirable. The reader will be exposed to basic concepts in modern biophysics such as entropic forces, phase separation, potentials of mean force, proton and electron transfer, heterogeneous reactions coherent and incoherent energy transfer as well as molecular motors. Basic concepts such as phase transitions of biopolymers, electrostatics, protonation equilibria, ion transport, radiationless transitions as well as energy- and electron transfer are discussed within the frame of simple models.

  1. Structure and biophysics

    CERN Document Server

    Puglisi, Joseph D

    2007-01-01

    This volume is a collection of articles from the proceedings of the ISSBMR 7th Course: Structure and Biophysics - New Technologies for Current Challenges in Biology and Beyond. This NATO Advanced Institute (ASI) was held in Erice at the Ettore Majorana Foundation and Centre for Scientific Culture on 22 June through 3 July 2005. The ASI brought together a diverse group of experts in the fields of Structural Biology, Biophysics and Physics. Prominent lecturers, from seven different countries, and students from around the world participated in the NATO ASI organized by Professors Joseph Puglisi (Stanford University, USA) and Alexander Arseniev (Moscow, RU). Advances in nuclear magnetic resonance spectroscopy (NMR) and x-ray crystallography have allowed the three-dimensional structures of many biological macromolecules and their complexes, including the ribosome and RNA polymerase to be solved. Fundamental principles of NMR spectroscopy and dynamics, x-ray crystallography, computation and experimental dynamics we...

  2. Biophysics an introduction

    CERN Document Server

    Cotteril, Rodney

    2002-01-01

    Biophysics: An Introduction, is a concise balanced introduction to this subject. Written in an accessible and readable style, the book takes a fresh, modern approach with the author successfully combining key concepts and theory with relevant applications and examples drawn from the field as a whole. Beginning with a brief introduction to the origins of biophysics, the book takes the reader through successive levels of complexity, from atoms to molecules, structures, systems and ultimately to the behaviour of organisms. The book also includes extensive coverage of biopolymers, biomembranes, biological energy, and nervous systems. The text not only explores basic ideas, but also discusses recent developments, such as protein folding, DNA/RNA conformations, molecular motors, optical tweezers and the biological origins of consciousness and intelligence.

  3. A Novel Methodology to Estimate Single-Tree Biophysical Parameters from 3D Digital Imagery Compared to Aerial Laser Scanner Data

    Directory of Open Access Journals (Sweden)

    Rocío Hernández-Clemente

    2014-11-01

    Full Text Available Airborne laser scanner (ALS data provide an enhanced capability to remotely map two key variables in forestry: leaf area index (LAI and tree height (H. Nevertheless, the cost, complexity and accessibility of this technology are not yet suited for meeting the broad demands required for estimating and frequently updating forest data. Here we demonstrate the capability of alternative solutions based on the use of low-cost color infrared (CIR cameras to estimate tree-level parameters, providing a cost-effective solution for forest inventories. ALS data were acquired with a Leica ALS60 laser scanner and digital aerial imagery (DAI was acquired with a consumer-grade camera modified for color infrared detection and synchronized with a GPS unit. In this paper we evaluate the generation of a DAI-based canopy height model (CHM from imagery obtained with low-cost CIR cameras using structure from motion (SfM and spatial interpolation methods in the context of a complex canopy, as in forestry. Metrics were calculated from the DAI-based CHM and the DAI-based Normalized Difference Vegetation Index (NDVI for the estimation of tree height and LAI, respectively. Results were compared with the models estimated from ALS point cloud metrics. Field measurements of tree height and effective leaf area index (LAIe were acquired from a total of 200 and 26 trees, respectively. Comparable accuracies were obtained in the tree height and LAI estimations using ALS and DAI data independently. Tree height estimated from DAI-based metrics (Percentile 90 (P90 and minimum height (MinH yielded a coefficient of determination (R2 = 0.71 and a root mean square error (RMSE = 0.71 m while models derived from ALS-based metrics (P90 yielded an R2 = 0.80 and an RMSE = 0.55 m. The estimation of LAI from DAI-based NDVI using Percentile 99 (P99 yielded an R2 = 0.62 and an RMSE = 0.17 m2/m−2. A comparative analysis of LAI estimation using ALS-based metrics (laser penetration index

  4. Recalibrating disease parameters for increasing realism in modeling epidemics in closed settings

    Directory of Open Access Journals (Sweden)

    Livio Bioglio

    2016-11-01

    Full Text Available Abstract Background The homogeneous mixing assumption is widely adopted in epidemic modelling for its parsimony and represents the building block of more complex approaches, including very detailed agent-based models. The latter assume homogeneous mixing within schools, workplaces and households, mostly for the lack of detailed information on human contact behaviour within these settings. The recent data availability on high-resolution face-to-face interactions makes it now possible to assess the goodness of this simplified scheme in reproducing relevant aspects of the infection dynamics. Methods We consider empirical contact networks gathered in different contexts, as well as synthetic data obtained through realistic models of contacts in structured populations. We perform stochastic spreading simulations on these contact networks and in populations of the same size under a homogeneous mixing hypothesis. We adjust the epidemiological parameters of the latter in order to fit the prevalence curve of the contact epidemic model. We quantify the agreement by comparing epidemic peak times, peak values, and epidemic sizes. Results Good approximations of the peak times and peak values are obtained with the homogeneous mixing approach, with a median relative difference smaller than 20 % in all cases investigated. Accuracy in reproducing the peak time depends on the setting under study, while for the peak value it is independent of the setting. Recalibration is found to be linear in the epidemic parameters used in the contact data simulations, showing changes across empirical settings but robustness across groups and population sizes. Conclusions An adequate rescaling of the epidemiological parameters can yield a good agreement between the epidemic curves obtained with a real contact network and a homogeneous mixing approach in a population of the same size. The use of such recalibrated homogeneous mixing approximations would enhance the accuracy and

  5. Recalibrating disease parameters for increasing realism in modeling epidemics in closed settings.

    Science.gov (United States)

    Bioglio, Livio; Génois, Mathieu; Vestergaard, Christian L; Poletto, Chiara; Barrat, Alain; Colizza, Vittoria

    2016-11-14

    The homogeneous mixing assumption is widely adopted in epidemic modelling for its parsimony and represents the building block of more complex approaches, including very detailed agent-based models. The latter assume homogeneous mixing within schools, workplaces and households, mostly for the lack of detailed information on human contact behaviour within these settings. The recent data availability on high-resolution face-to-face interactions makes it now possible to assess the goodness of this simplified scheme in reproducing relevant aspects of the infection dynamics. We consider empirical contact networks gathered in different contexts, as well as synthetic data obtained through realistic models of contacts in structured populations. We perform stochastic spreading simulations on these contact networks and in populations of the same size under a homogeneous mixing hypothesis. We adjust the epidemiological parameters of the latter in order to fit the prevalence curve of the contact epidemic model. We quantify the agreement by comparing epidemic peak times, peak values, and epidemic sizes. Good approximations of the peak times and peak values are obtained with the homogeneous mixing approach, with a median relative difference smaller than 20 % in all cases investigated. Accuracy in reproducing the peak time depends on the setting under study, while for the peak value it is independent of the setting. Recalibration is found to be linear in the epidemic parameters used in the contact data simulations, showing changes across empirical settings but robustness across groups and population sizes. An adequate rescaling of the epidemiological parameters can yield a good agreement between the epidemic curves obtained with a real contact network and a homogeneous mixing approach in a population of the same size. The use of such recalibrated homogeneous mixing approximations would enhance the accuracy and realism of agent-based simulations and limit the intrinsic biases of

  6. Hematological Parameters in Broilers Reared in a Closed Production Farm in the Low Tropics

    Directory of Open Access Journals (Sweden)

    Berta Lucía Avilez Colón

    2015-05-01

    Full Text Available Hematology and blood chemistry are useful tools to establish a definitive diagnosis, to guide and explore the nature of pathophysiological situations that affect birds. Several diseases of poultry can change blood parameters, which are little studied in Colombia. This study aims to determine degrees of blood hematological parameters in broilers (1-42 days old reared under experimental conditions. Blood samples were taken during the second, fourth and sixth weeks of age. Average results were: hematocrit (PCV %: 27.53; hemoglobin (Hb g/dL: 9.20; mean corpuscular volume (MCV fl: 43.10; mean corpuscular hemoglobin concentration (MCHC g/dL: 33.17; erythrocytes (Eri 106 μl: 6.98; leukocytes (Leu 103μL: 19.69; absolute relative values for lymphocyte (Lin %: 72.58; heterophile (Het %: 35; monocytes (Mon %: 9.8; eosinophils (Eos %: 17.8, and basophils (Bas %: 1.08. These results are within normal ranges, and present small variations attributable to environmental conditions and to those of confinement. Therefore, further studies are needed on this topic in the region.

  7. Biophysics and systems biology.

    Science.gov (United States)

    Noble, Denis

    2010-03-13

    Biophysics at the systems level, as distinct from molecular biophysics, acquired its most famous paradigm in the work of Hodgkin and Huxley, who integrated their equations for the nerve impulse in 1952. Their approach has since been extended to other organs of the body, notably including the heart. The modern field of computational biology has expanded rapidly during the first decade of the twenty-first century and, through its contribution to what is now called systems biology, it is set to revise many of the fundamental principles of biology, including the relations between genotypes and phenotypes. Evolutionary theory, in particular, will require re-assessment. To succeed in this, computational and systems biology will need to develop the theoretical framework required to deal with multilevel interactions. While computational power is necessary, and is forthcoming, it is not sufficient. We will also require mathematical insight, perhaps of a nature we have not yet identified. This article is therefore also a challenge to mathematicians to develop such insights.

  8. Biophysical pathology in cancer transformation

    Czech Academy of Sciences Publication Activity Database

    Pokorný, Jiří; Pokorný, Jan

    S1, Nov (2013), s. 1-9 ISSN 2324-9110 R&D Projects: GA ČR(CZ) GAP102/11/0649 Institutional support: RVO:68378271 ; RVO:67985882 Keywords : cancer biophysics * Warburg effect * reverse Warburg effect * biological electrodynamics * coherent states Subject RIV: BO - Biophysics

  9. Radiation biophysics in space

    International Nuclear Information System (INIS)

    Buecker, H.; Horneck, G.

    1983-01-01

    In a demonstration experiment bacterium sporules have been exposed to the space vacuum and to the solar radiation field at 254 nm, with the following results: 1) a short vacuum exposition of 1.3 h does not affect the vitality of the sporules, 2) the survival rate of humid sporules after UV-irradiation is consistent with terrestrial control samples, 3) after a simultaneous exposition to vacuum and solar UV-radiation the effect on the sporules is enhanced by a factor of ten as compared to the situation without vaccum exposition. Additional studies in biophysical simulation systems revealed, that the enhanced UV sensitivity is caused by the dehydration of the sporules. By this process the structure of the essential macromolecules in cell, such as DNA and proteins, is modified such that new photo-products can be formed. For these products the cells have no effective repair systems. (AJ) [de

  10. Biophysics of DNA

    CERN Document Server

    Vologodskii, Alexander

    2015-01-01

    Surveying the last sixty years of research, this book describes the physical properties of DNA in the context of its biological functioning. It is designed to enable both students and researchers of molecular biology, biochemistry and physics to better understand the biophysics of DNA, addressing key questions and facilitating further research. The chapters integrate theoretical and experimental approaches, emphasising throughout the importance of a quantitative knowledge of physical properties in building and analysing models of DNA functioning. For example, the book shows how the relationship between DNA mechanical properties and the sequence specificity of DNA-protein binding can be analyzed quantitatively by using our current knowledge of the physical and structural properties of DNA. Theoretical models and experimental methods in the field are critically considered to enable the reader to engage effectively with the current scientific literature on the physical properties of DNA.

  11. Theoretical molecular biophysics

    CERN Document Server

    Scherer, Philipp O J

    2017-01-01

    This book gives an introduction to molecular biophysics. It starts from material properties at equilibrium related to polymers, dielectrics and membranes. Electronic spectra are developed for the understanding of elementary dynamic processes in photosynthesis including proton transfer and dynamics of molecular motors. Since the molecular structures of functional groups of bio-systems were resolved, it has become feasible to develop a theory based on the quantum theory and statistical physics with emphasis on the specifics of the high complexity of bio-systems. This introduction to molecular aspects of the field focuses on solvable models. Elementary biological processes provide as special challenge the presence of partial disorder in the structure which does not destroy the basic reproducibility of the processes. Apparently the elementary molecular processes are organized in a way to optimize the efficiency. Learning from nature by means exploring the relation between structure and function may even help to b...

  12. Biophysics and cancer

    CERN Document Server

    Nicolini, Claudio

    1986-01-01

    Since the early times of the Greek philosophers Leucippus and Democritus, and later of the Roman philosopher Lucretius, a simple, fundamental idea emerged that brought the life sciences into the realm of the physical sciences. Atoms, after various interactions, were assumed to acquire stable configurations that corresponded either to the living or to the inanimate world. This simple and unitary theory, which has evolved in successive steps to our present time, remarkably maintained its validity despite several centuries of alternative vicissitudes, and is the foundation of modern biophysics. Some of the recent developments of this ancient idea are the discovery of the direct relationship between spatial structures and chemical activity of such molecules as methane and benzene, and the later discovery of the three-dimensional structure of double-helical DNA, and of its relationship with biological activity. The relationship between the structure of various macromolecules and the function of living cells was on...

  13. Effectiveness of Percutaneous Proximal Closing Wedge Osteotomy With Akin Osteotomy to Correct Severe Hallux Valgus Determined by Radiographic Parameters.

    Science.gov (United States)

    Kurashige, Toshinori; Suzuki, Seiichi

    2017-04-01

    Some authors reported the results from percutaneous distal metatarsal osteotomy for hallux valgus recently. On the other hand, there are few reports of percutaneous proximal metatarsal osteotomy. The purpose of the present study was to evaluate the radiographic results of percutaneous proximal closing wedge osteotomy with Akin osteotomy for correction of severe hallux valgus and increasing longitudinal arch height. Consecutive 17 feet (mean age = 70.8 years) were investigated. The mean follow-up was 22 months. Excision of medial eminence, distal soft tissue release, and Akin osteotomy were all performed percutaneously and concurrently. Weight-bearing anteroposterior and lateral radiographs of the feet were acquired preoperatively and at final follow-up. On the anteroposterior radiographs, hallux valgus angle, intermetatarsal angle, and first metatarsal shortening were measured. On the lateral radiographs, talometatarsal angle, calcaneal pitch angle, and first metatarsal dorsiflexion were measured. The average improvements in hallux valgus angle and intermetatarsal angle were 27.6° and 9.9°, respectively. The average first metatarsal shortening was 2.7 mm. The first metatarsal dorsiflexion improved by 2.2°; however, other parameters did not improve significantly. In conclusion, percutaneous proximal closing wedge osteotomy with Akin osteotomy corrects severe hallux valgus; however, the procedure does not increase the medial longitudinal arch. Therapeutic, Level IV: Case series.

  14. The Biophysics Microgravity Initiative

    Science.gov (United States)

    Gorti, S.

    2016-01-01

    Biophysical microgravity research on the International Space Station using biological materials has been ongoing for several decades. The well-documented substantive effects of long duration microgravity include the facilitation of the assembly of biological macromolecules into large structures, e.g., formation of large protein crystals under micro-gravity. NASA is invested not only in understanding the possible physical mechanisms of crystal growth, but also promoting two flight investigations to determine the influence of µ-gravity on protein crystal quality. In addition to crystal growth, flight investigations to determine the effects of shear on nucleation and subsequent formation of complex structures (e.g., crystals, fibrils, etc.) are also supported. It is now considered that long duration microgravity research aboard the ISS could also make possible the formation of large complex biological and biomimetic materials. Investigations of various materials undergoing complex structure formation in microgravity will not only strengthen NASA science programs, but may also provide invaluable insight towards the construction of large complex tissues, organs, or biomimetic materials on Earth.

  15. Biophysics of protein evolution and evolutionary protein biophysics

    Science.gov (United States)

    Sikosek, Tobias; Chan, Hue Sun

    2014-01-01

    The study of molecular evolution at the level of protein-coding genes often entails comparing large datasets of sequences to infer their evolutionary relationships. Despite the importance of a protein's structure and conformational dynamics to its function and thus its fitness, common phylogenetic methods embody minimal biophysical knowledge of proteins. To underscore the biophysical constraints on natural selection, we survey effects of protein mutations, highlighting the physical basis for marginal stability of natural globular proteins and how requirement for kinetic stability and avoidance of misfolding and misinteractions might have affected protein evolution. The biophysical underpinnings of these effects have been addressed by models with an explicit coarse-grained spatial representation of the polypeptide chain. Sequence–structure mappings based on such models are powerful conceptual tools that rationalize mutational robustness, evolvability, epistasis, promiscuous function performed by ‘hidden’ conformational states, resolution of adaptive conflicts and conformational switches in the evolution from one protein fold to another. Recently, protein biophysics has been applied to derive more accurate evolutionary accounts of sequence data. Methods have also been developed to exploit sequence-based evolutionary information to predict biophysical behaviours of proteins. The success of these approaches demonstrates a deep synergy between the fields of protein biophysics and protein evolution. PMID:25165599

  16. Integrated Molecular and Cellular Biophysics

    CERN Document Server

    Raicu, Valerica

    2008-01-01

    This book integrates concepts and methods from physics, biology, biochemistry and physical chemistry into a standalone, unitary text of biophysics that aims to provide a quantitative description of structures and processes occurring in living matter. The book introduces graduate physics students and physicists interested in biophysics research to 'classical' as well as emerging areas of biophysics. The advanced undergraduate physics students and the life scientists are also invited to join in, by building on their knowledge of basic physics. Essential notions of biochemistry and biology are introduced, as necessary, throughout the book, while the reader's familiarity with basic knowledge of physics is assumed. Topics covered include interactions between biological molecules, physical chemistry of phospholipids association into bilayer membranes, DNA and protein structure and folding, passive and active electrical properties of the cell membrane, classical as well as fractal aspects of reaction kinetics and di...

  17. The biophysics of neuronal growth

    International Nuclear Information System (INIS)

    Franze, Kristian; Guck, Jochen

    2010-01-01

    For a long time, neuroscience has focused on biochemical, molecular biological and electrophysiological aspects of neuronal physiology and pathology. However, there is a growing body of evidence indicating the importance of physical stimuli for neuronal growth and development. In this review we briefly summarize the historical background of neurobiophysics and give an overview over the current understanding of neuronal growth from a physics perspective. We show how biophysics has so far contributed to a better understanding of neuronal growth and discuss current inconsistencies. Finally, we speculate how biophysics may contribute to the successful treatment of lesions to the central nervous system, which have been considered incurable until very recently.

  18. Radiobiology, biochemistry and radiation biophysics at CYLAB

    International Nuclear Information System (INIS)

    Ftacnikova, S.

    1998-01-01

    The Cyclotron Laboratory (CYLAB) should fill the gap in the field of nuclear medicine, radiotherapy, basic research, metrology of ionizing radiation, education and implications of accelerator technology existing today in Slovak Republic. The main planned activities of this facility are in the fields of nuclear medicine (production of radioisotopes for Positron Emission Tomography - PET and for oncology) and radiotherapy (neutron capture therapy, fast neutron therapy and proton therapy). The radiobiological and biophysical research will be closely connected with medical applications, particularly with radiotherapy. Problems to be addressed include the determination of the values of Relative Biological Effectiveness (RBE) for different types of ionizing radiation involved in the therapy, microdosimetric measurements and calculations, which are indispensable in the calculation of the absorbed dose (lineal and specific energy spectra) at the cellular and macromolecular level. Radiation biophysics and medical physics help in creating therapeutic plans for radiotherapy (NCT and fast neutron therapy). In nuclear medicine, in diagnostic and therapeutical procedures it is necessary to assess the biodistribution of radiopharmaceuticals and to calculate doses in target and critical organs and to determine whole body burden - effective equivalent dose for newly developed radiopharmaceuticals

  19. Fundamental Concepts in Biophysics Volume 1

    CERN Document Server

    Jue, Thomas

    2009-01-01

    HANDBOOK OF MODERN BIOPHYSICS Series Editor Thomas Jue, PhD Handbook of Modern Biophysics brings current biophysics topics into focus, so that biology, medical, engineering, mathematics, and physical-science students or researchers can learn fundamental concepts and the application of new techniques in addressing biomedical challenges. Chapters explicate the conceptual framework of the physics formalism and illustrate the biomedical applications. With the addition of problem sets, guides to further study, and references, the interested reader can continue to explore independently the ideas presented. Volume I: Fundamental Concepts in Biophysics Editor Thomas Jue, PhD In Fundamental Concepts in Biophysics, prominent professors have established a foundation for the study of biophysics related to the following topics: Mathematical Methods in Biophysics Quantum Mechanics Basic to Biophysical Methods Computational Modeling of Receptor–Ligand Binding and Cellular Signaling Processes Fluorescence Spectroscopy Elec...

  20. Biophysical applications of satellite remote sensing

    CERN Document Server

    Hanes, Jonathan

    2014-01-01

    Including an introduction and historical overview of the field, this comprehensive synthesis of the major biophysical applications of satellite remote sensing includes in-depth discussion of satellite-sourced biophysical metrics such as leaf area index.

  1. Effect of stimulus parameters and contraction level on inhibitory responses in human jaw-closing muscles: Implications for contingent stimulation

    DEFF Research Database (Denmark)

    Jadidi, F; Wang, K; Arendt-Nielsen, Lars

    2009-01-01

      Objective: Examine the effect of stimulus duration as well as stimulus intensity and level of muscle contraction on the inhibitory responses in human jaw-closing muscles. Design: The inhibitory jaw-reflexes, ES1 and ES2, were recorded in the surface electromyogram (EMG) of masseter and temporal...

  2. Biophysical and lipofection studies of DOTAP analogs.

    Science.gov (United States)

    Regelin, A E; Fankhaenel, S; Gürtesch, L; Prinz, C; von Kiedrowski, G; Massing, U

    2000-03-15

    In order to investigate the relationship between lipid structure and liposome-mediated gene transfer, we have studied biophysical parameters and transfection properties of monocationic DOTAP analogs, systematically modified in their non-polar hydrocarbon chains. Stability, size and (by means of anisotropy profiles) membrane fluidity of liposomes and lipoplexes were determined, and lipofection efficiency was tested in a luciferase reporter gene assay. DOTAP analogs were used as single components or combined with a helper lipid, either DOPE or cholesterol. Stability of liposomes was a precondition for formation of temporarily stable lipoplexes. Addition of DOPE or cholesterol improved liposome and lipoplex stability. Transfection efficiencies of lipoplexes based on pure DOTAP analogs could be correlated with stability data and membrane fluidity at transfection temperature. Inclusion of DOPE led to rather uniform transfection and anisotropy profiles, corresponding to lipoplex stability. Cholesterol-containing lipoplexes were generally stable, showing high transfection efficiency at low relative fluidity. Our results demonstrate that the efficiency of gene transfer mediated by monocationic lipids is greatly influenced by lipoplex biophysics due to lipid composition. The measurement of fluorescence anisotropy is an appropriate method to characterize membrane fluidity within a defined system of liposomes or lipoplexes and may be helpful to elucidate structure-activity relationships.

  3. Biophysics of NASA radiation quality factors

    International Nuclear Information System (INIS)

    Cucinotta, Francis A.

    2015-01-01

    NASA has implemented new radiation quality factors (QFs) for projecting cancer risks from space radiation exposures to astronauts. The NASA QFs are based on particle track structure concepts with parameters derived from available radiobiology data, and NASA introduces distinct QFs for solid cancer and leukaemia risk estimates. The NASA model was reviewed by the US National Research Council and approved for use by NASA for risk assessment for International Space Station missions and trade studies of future exploration missions to Mars and other destinations. A key feature of the NASA QFs is to represent the uncertainty in the QF assessments and evaluate the importance of the QF uncertainty to overall uncertainties in cancer risk projections. In this article, the biophysical basis for the probability distribution functions representing QF uncertainties was reviewed, and approaches needed to reduce uncertainties were discussed. (author)

  4. Biophysics of NASA radiation quality factors.

    Science.gov (United States)

    Cucinotta, Francis A

    2015-09-01

    NASA has implemented new radiation quality factors (QFs) for projecting cancer risks from space radiation exposures to astronauts. The NASA QFs are based on particle track structure concepts with parameters derived from available radiobiology data, and NASA introduces distinct QFs for solid cancer and leukaemia risk estimates. The NASA model was reviewed by the US National Research Council and approved for use by NASA for risk assessment for International Space Station missions and trade studies of future exploration missions to Mars and other destinations. A key feature of the NASA QFs is to represent the uncertainty in the QF assessments and evaluate the importance of the QF uncertainty to overall uncertainties in cancer risk projections. In this article, the biophysical basis for the probability distribution functions representing QF uncertainties was reviewed, and approaches needed to reduce uncertainties were discussed. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. FindFoci: a focus detection algorithm with automated parameter training that closely matches human assignments, reduces human inconsistencies and increases speed of analysis.

    Directory of Open Access Journals (Sweden)

    Alex D Herbert

    Full Text Available Accurate and reproducible quantification of the accumulation of proteins into foci in cells is essential for data interpretation and for biological inferences. To improve reproducibility, much emphasis has been placed on the preparation of samples, but less attention has been given to reporting and standardizing the quantification of foci. The current standard to quantitate foci in open-source software is to manually determine a range of parameters based on the outcome of one or a few representative images and then apply the parameter combination to the analysis of a larger dataset. Here, we demonstrate the power and utility of using machine learning to train a new algorithm (FindFoci to determine optimal parameters. FindFoci closely matches human assignments and allows rapid automated exploration of parameter space. Thus, individuals can train the algorithm to mirror their own assignments and then automate focus counting using the same parameters across a large number of images. Using the training algorithm to match human assignments of foci, we demonstrate that applying an optimal parameter combination from a single image is not broadly applicable to analysis of other images scored by the same experimenter or by other experimenters. Our analysis thus reveals wide variation in human assignment of foci and their quantification. To overcome this, we developed training on multiple images, which reduces the inconsistency of using a single or a few images to set parameters for focus detection. FindFoci is provided as an open-source plugin for ImageJ.

  6. Biophysical models of radiobiological effects

    International Nuclear Information System (INIS)

    Obaturov, G.M.

    1987-01-01

    Radiobiological effect models at different organization levels, developed by the author, are presented. Classification and analysis of concepts and biophysical models at molecular, genetic and cellular levels, developed by Soviet and foreign authors in comparison to inherent models, are conducted from the viewpoint of system approach to radiobiological processes and of modelling principles. Models are compared with each other, limits of their applicability and drawbacks are determined. Evaluation of the model truthfulness is conducted according to a number of criteria, ways of further investigations and experimental examination of some models are proposed

  7. Biophysical and physicochemical methods differentiate highly ligand-efficient human D-amino acid oxidase inhibitors.

    Science.gov (United States)

    Lange, Jos H M; Venhorst, Jennifer; van Dongen, Maria J P; Frankena, Jurjen; Bassissi, Firas; de Bruin, Natasja M W J; den Besten, Cathaline; de Beer, Stephanie B A; Oostenbrink, Chris; Markova, Natalia; Kruse, Chris G

    2011-10-01

    Many early drug research efforts are too reductionist thereby not delivering key parameters such as kinetics and thermodynamics of target-ligand binding. A set of human D-Amino Acid Oxidase (DAAO) inhibitors 1-6 was applied to demonstrate the impact of key biophysical techniques and physicochemical methods in the differentiation of chemical entities that cannot be adequately distinguished on the basis of their normalized potency (ligand efficiency) values. The resulting biophysical and physicochemical data were related to relevant pharmacodynamic and pharmacokinetic properties. Surface Plasmon Resonance data indicated prolonged target-ligand residence times for 5 and 6 as compared to 1-4, based on the observed k(off) values. The Isothermal Titration Calorimetry-derived thermodynamic binding profiles of 1-6 to the DAAO enzyme revealed favorable contributions of both ΔH and ΔS to their ΔG values. Surprisingly, the thermodynamic binding profile of 3 elicited a substantially higher favorable contribution of ΔH to ΔG in comparison with the structurally closely related fused bicyclic acid 4. Molecular dynamics simulations and free energy calculations of 1, 3, and 4 led to novel insights into the thermodynamic properties of the binding process at an atomic level and in the different thermodynamic signatures of 3 and 4. The presented holistic approach is anticipated to facilitate the identification of compounds with best-in-class properties at an early research stage. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  8. Assessment of the anterior chamber parameters after laser iridotomy in primary angle close suspect using Pentacam and gonioscopy.

    Science.gov (United States)

    Esmaeili, Alireza; Barazandeh, Behzad; Ahmadi, Sina; Haghi, Alireza; Ahmadi Hosseini, Seyed Mahdi; Abolbashari, Fereshteh

    2013-01-01

    To evaluate the changes in the anterior segment parameters of the subjects with primary angle closure suspect (PACS) before and after laser iridotomy (LI) using the Pentacam and gonioscopy. Forty-eight eyes of 48 PACS were included. Anterior chamber angle (ACA), central anterior chamber depth (ACD), anterior chamber volume (ACV) and central corneal thickness (CCT) were recorded from the Pentacam before and one month after LI. ACA was graded according to Shaffer classification using the Goldmann gonioscopy. ACA increased significantly from 25.59±4.41 to 26.46±4.33 degrees (P=0.009) and ACV changed from 85.97±16.07mm(3) to 99.25±15.83mm(3) (P=0.000). The changes in ACD, CCT and intraocular pressure were non-significant (P>0.05). Gonioscopy showed significant widening of the Shaffer angle in 4 quadrants (P<0.001). Pentacam can serve as the objective instrument in assessing the efficacy of LI.

  9. A Discussion of Oxygen Recovery Definitions and Key Performance Parameters for Closed-Loop Atmosphere Revitalization Life Support Technology Development

    Science.gov (United States)

    Abney, Morgan B.; Perry, Jay L.

    2016-01-01

    Over the last 55 years, NASA has evolved life support for crewed space exploration vehicles from simple resupply during Project Mercury to the complex and highly integrated system of systems aboard the International Space Station. As NASA targets exploration destinations farther from low Earth orbit and mission durations of 500 to 1000 days, life support systems must evolve to meet new requirements. In addition to having more robust, reliable, and maintainable hardware, limiting resupply becomes critical for managing mission logistics and cost. Supplying a crew with the basics of food, water, and oxygen become more challenging as the destination ventures further from Earth. Aboard ISS the Atmosphere Revitalization Subsystem (ARS) supplies the crew's oxygen demand by electrolyzing water. This approach makes water a primary logistics commodity that must be managed carefully. Chemical reduction of metabolic carbon dioxide (CO2) provides a method of recycling oxygen thereby reducing the net ARS water demand and therefore minimizing logistics needs. Multiple methods have been proposed to achieve this recovery and have been reported in the literature. However, depending on the architecture and the technology approach, "oxygen recovery" can be defined in various ways. This discontinuity makes it difficult to compare technologies directly. In an effort to clarify community discussions of Oxygen Recovery, we propose specific definitions and describe the methodology used to arrive at those definitions. Additionally, we discuss key performance parameters for Oxygen Recovery technology development including challenges with comparisons to state-of-the-art.

  10. Effect of the grain sizes on the photovoltaic parameters of CdTe solar cells prepared by close space sublimation method

    International Nuclear Information System (INIS)

    Potlog, T.

    2007-01-01

    Thin Film CdS/CdTe solar cells were fabricated by Close Space Sublimation at the substrate temperature ranging from 300 degrees ± 5 degrees to 340 degrees ± degrees. The best photovoltaic parameters were achieved at substrate temperature 320 degrees and source temperature 610 degrees. The open circuit voltage and current density changes significantly with the substrate temperature and depends on the dimension of the grain sizes. Grain size is an efficiency limiting parameter for CdTe layers with large grains. The open circuit voltage and current density are the best for the cells having dimension of grains between 1.0 μm and ∼ 5.0 μm. CdS/CdTe solar cells with an efficiency of ∼ 10% were obtained. (author)

  11. The Study of Deposition Parameters, Properties for PVD TixN and CrxN Coatings Using a Closed Field Unbalanced Magnetron Sputter Ion Plating System

    Institute of Scientific and Technical Information of China (English)

    Hailin Sun; Susan Field; Jian Chen; Dennis. G. Teer

    2004-01-01

    Closed Field Unbalanced Magnetron Sputter Ion Plating (CFUBMSIP) systems have been used increasingly for PVD coating in recent years. TiN and CrN coatings, commonly used as the basic coating for a number of different hard coatings, have been chosen to study the coating process parameters for the CFUBMSIP system. In this paper, the process parameters, such as substrate temperature, substrate bias and OEM control, have been carefully examined to achieve hard and wear-resistance coatings with good adhesion. The coating structure and orientation were found to change according to the coating parameters. The Rockwell test and Scratch test were carried out to examine the coating adhesion; pin-on-disc testing was used to estimate the wear-resistant; micro-hardness was also used to determine coating hardness. HSS drill testing has been carried out to study the general properties of the coating for cutting tool application. A combination of process parameters can be selected to achieve good performance for the TiN and CrN coatings.

  12. Nanoscale biophysics of the cell

    CERN Document Server

    Ashrafuzzaman, Mohammad

    2018-01-01

    Macroscopic cellular structures and functions are generally investigated using biological and biochemical approaches. But these methods are no longer adequate when one needs to penetrate deep into the small-scale structures and understand their functions. The cell is found to hold various physical structures, molecular machines, and processes that require physical and mathematical approaches to understand and indeed manipulate them. Disorders in general cellular compartments, perturbations in single molecular structures, drug distribution therein, and target specific drug-binding, etc. are mostly physical phenomena. This book will show how biophysics has revolutionized our way of addressing the science and technology of nanoscale structures of cells, and also describes the potential for manipulating the events that occur in them.

  13. Quantum Nanobiology and Biophysical Chemistry

    DEFF Research Database (Denmark)

    2013-01-01

    An introduction was provided in the first issue by way of an Editorial to this special two issue volume of Current Physical Chemistry – “Quantum Nanobiology and Biophysical Chemistry” [1]. The Guest Editors would like to thank all the authors and referees who have contributed to this second issue....... Wu et al. use density functional theory to explore the use of Ni/Fe bimetallic nanotechnology in the bioremediation of decabromo-diphenyl esters. Araújo-Chaves et al. explore the binding and reactivity of Mn(III) porphyrins in the membrane mimetic setting of model liposomal systems. Claussen et al....... demonstrate extremely low detection performance of acyl-homoserine lactone in a biologically relevant system using surface enhanced Raman spectroscopy. Sugihara and Bondar evaluate the influence of methyl-groups and the protein environment on retinal geometries in rhodopsin and bacteriorhodopsin, two...

  14. Historical and Critical Review on Biophysical Economics

    Science.gov (United States)

    Adigüzel, Yekbun

    2016-07-01

    Biophysical economics is initiated with the long history of the relation of economics with ecological basis and biophysical perspectives of the physiocrats. It inherently has social, economic, biological, environmental, natural, physical, and scientific grounds. Biological entities in economy like the resources, consumers, populations, and parts of production systems, etc. could all be dealt by biophysical economics. Considering this wide scope, current work is a “biophysical economics at a glance” rather than a comprehensive review of the full range of topics that may just be adequately covered in a book-length work. However, the sense of its wide range of applications is aimed to be provided to the reader in this work. Here, modern approaches and biophysical growth theory are presented after the long history and an overview of the concepts in biophysical economics. Examples of the recent studies are provided at the end with discussions. This review is also related to the work by Cleveland, “Biophysical Economics: From Physiocracy to Ecological Economics and Industrial Ecology” [C. J. Cleveland, in Advances in Bioeconomics and Sustainability: Essay in Honor of Nicholas Gerogescu-Roegen, eds. J. Gowdy and K. Mayumi (Edward Elgar Publishing, Cheltenham, England, 1999), pp. 125-154.]. Relevant parts include critics and comments on the presented concepts in a parallelized fashion with the Cleveland’s work.

  15. Biophysical studies of irradiated thymocytes. 1. Surface changes

    Energy Technology Data Exchange (ETDEWEB)

    Sungurov, A Yu; Tokalov, S V; Petrov, Yu P; Sharlaeva, T M

    1985-08-15

    In order to study postirradiation changes in thymus lymphocyte surface, a number of biophysical analytical methods was used: the cell two-partition method, the physical adhesion method, fluorescence intensity and binding parameters of negatively charged ANS probe. Reduction of cell distribution factor in two-phase system and adhesion of thymocytes to cotton 1 hour after irradiation, as well as abrupt change in parameters of binding the probe in the interval of 3-4 hours after X-ray irradiation at the dose of 4 Gy are demonstrated.

  16. [Biophysical principles of collagen cross-linking].

    Science.gov (United States)

    Spörl, E; Raiskup-Wolf, F; Pillunat, L E

    2008-02-01

    The reduced mechanical stability of the cornea in keratoconus or in keratectasia after Lasik may be increased by photooxidative cross-linking of corneal collagen. The biophysical principles are compiled for the safe and effective application of this new treatment method. The setting of the therapy parameters should be elucidated from the absorption behaviour of the cornea. The safety of the method for the endothelium cells and the lens will be discussed. The induced cross-links are shown to be the result of changes in the physico-chemical properties of the cornea. To reach a high absorption of the irradiation energy in the cornea, riboflavin of a concentration of 0.1% and UV light of a wavelength of 370 nm, corresponding to the relative maximum of absorption of riboflavin, were used. An irradiance of 3 mW/cm(2) and an irradiation time of 30 min lead to an increase of the mechanical stiffness. The endothelium cells will be protected due to the high absorption within the cornea, that means the damaging threshold of the endothelium cells will not be reached in a 400 microm thick stroma. As evidence for cross-links we can consider the increase of the biomechanical stiffness, the increased resistance against enzymatic degradation, a higher shrinkage temperature, a lower swelling rate and an increased diameter of collagen fibres. The therapy parameters were tested experimentally and have been proven clinically in the corneal collagen cross-linking. These parameters should be respected to reach a safe cross-linking effect without damage of the adjacent tissues.

  17. A Slater parameter optimisation interface for the CIV3 atomic structure code and its possible use with the R-matrix close coupling collision code

    International Nuclear Information System (INIS)

    Fawcett, B.C.; Hibbert, A.

    1989-11-01

    Details are here provided of amendments to the atomic structure code CIV3 which allow the optional adjustment of Slater parameters and average energies of configurations so that they result in improved energy levels and eigenvectors. It is also indicated how, in principle, the resultant improved eigenvectors can be utilised by the R-matrix collision code, thus providing an optimised target for close coupling collision strength calculations. An analogous computational method was recently reported for distorted wave collision strength calculations and applied to Fe XIII. The general method is suitable for the computation of collision strengths for complex ions and in some cases can then provide a basis for collision strength calculations in ions where ab initio computations break down or result in unnecessarily large errors. (author)

  18. An introduction to environmental biophysics

    CERN Document Server

    Campbell, Gaylon S

    1977-01-01

    The study of environmental biophysics probably began earlier in man's history than that of any other science. The study of organism-environment interaction provided a key to survival and progress. Systematic study of the science and recording of experimental results goes back many hundreds of years. Ben­ jamin Franklin, the early American statesman, inventor, printer, and scientist studied conduction, evaporation, and radiation. One of his observations is as follows: My desk on which I now write, and the lock of my desk, are both exposed to the same temperature of the air, and have therefore the same degree of heat or cold; yet if I lay my hand successively on the wood and on the metal, the latter feels much the coldest, not that it is really so, but being a better conductor, it more readily than the wood takes away and draws into itself the fire that was in my skin. 1 Franklin probably was not the first to discover this principle, and certainly was not the last. Modem researchers rediscover this principle f...

  19. Applications of synchrotron radiation in Biophysics

    International Nuclear Information System (INIS)

    Bemski, G.

    1983-01-01

    A short introduction to the generation of the synchrotron radiation is made. Following, the applications of such a radiation in biophysics with emphasis to the study of the hemoglobin molecule are presented. (L.C.) [pt

  20. Modelling benthic biophysical drivers of ecosystem structure and biogeochemical response

    Science.gov (United States)

    Stephens, Nicholas; Bruggeman, Jorn; Lessin, Gennadi; Allen, Icarus

    2016-04-01

    The fate of carbon deposited at the sea floor is ultimately decided by biophysical drivers that control the efficiency of remineralisation and timescale of carbon burial in sediments. Specifically, these drivers include bioturbation through ingestion and movement, burrow-flushing and sediment reworking, which enhance vertical particulate transport and solute diffusion. Unfortunately, these processes are rarely satisfactorily resolved in models. To address this, a benthic model that explicitly describes the vertical position of biology (e.g., habitats) and biogeochemical processes is presented that includes biological functionality and biogeochemical response capturing changes in ecosystem structure, benthic-pelagic fluxes and biodiversity on inter-annual timescales. This is demonstrated by the model's ability to reproduce temporal variability in benthic infauna, vertical pore water nutrients and pelagic-benthic solute fluxes compared to in-situ data. A key advance is the replacement of bulk parameterisation of bioturbation by explicit description of the bio-physical processes responsible. This permits direct comparison with observations and determination of key parameters in experiments. Crucially, the model resolves the two-way interaction between sediment biogeochemistry and ecology, allowing exploration of the benthic response to changing environmental conditions, the importance of infaunal functional traits in shaping benthic ecological structure and the feedback the resulting bio-physical processes exert on pore water nutrient profiles. The model is actively being used to understand shelf sea carbon cycling, the response of the benthos to climatic change, food provision and other societal benefits.

  1. Single Nucleobase Identification Using Biophysical Signatures from Nanoelectronic Quantum Tunneling.

    Science.gov (United States)

    Korshoj, Lee E; Afsari, Sepideh; Khan, Sajida; Chatterjee, Anushree; Nagpal, Prashant

    2017-03-01

    Nanoelectronic DNA sequencing can provide an important alternative to sequencing-by-synthesis by reducing sample preparation time, cost, and complexity as a high-throughput next-generation technique with accurate single-molecule identification. However, sample noise and signature overlap continue to prevent high-resolution and accurate sequencing results. Probing the molecular orbitals of chemically distinct DNA nucleobases offers a path for facile sequence identification, but molecular entropy (from nucleotide conformations) makes such identification difficult when relying only on the energies of lowest-unoccupied and highest-occupied molecular orbitals (LUMO and HOMO). Here, nine biophysical parameters are developed to better characterize molecular orbitals of individual nucleobases, intended for single-molecule DNA sequencing using quantum tunneling of charges. For this analysis, theoretical models for quantum tunneling are combined with transition voltage spectroscopy to obtain measurable parameters unique to the molecule within an electronic junction. Scanning tunneling spectroscopy is then used to measure these nine biophysical parameters for DNA nucleotides, and a modified machine learning algorithm identified nucleobases. The new parameters significantly improve base calling over merely using LUMO and HOMO frontier orbital energies. Furthermore, high accuracies for identifying DNA nucleobases were observed at different pH conditions. These results have significant implications for developing a robust and accurate high-throughput nanoelectronic DNA sequencing technique. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Assimilation of Biophysical Neuronal Dynamics in Neuromorphic VLSI.

    Science.gov (United States)

    Wang, Jun; Breen, Daniel; Akinin, Abraham; Broccard, Frederic; Abarbanel, Henry D I; Cauwenberghs, Gert

    2017-12-01

    Representing the biophysics of neuronal dynamics and behavior offers a principled analysis-by-synthesis approach toward understanding mechanisms of nervous system functions. We report on a set of procedures assimilating and emulating neurobiological data on a neuromorphic very large scale integrated (VLSI) circuit. The analog VLSI chip, NeuroDyn, features 384 digitally programmable parameters specifying for 4 generalized Hodgkin-Huxley neurons coupled through 12 conductance-based chemical synapses. The parameters also describe reversal potentials, maximal conductances, and spline regressed kinetic functions for ion channel gating variables. In one set of experiments, we assimilated membrane potential recorded from one of the neurons on the chip to the model structure upon which NeuroDyn was designed using the known current input sequence. We arrived at the programmed parameters except for model errors due to analog imperfections in the chip fabrication. In a related set of experiments, we replicated songbird individual neuron dynamics on NeuroDyn by estimating and configuring parameters extracted using data assimilation from intracellular neural recordings. Faithful emulation of detailed biophysical neural dynamics will enable the use of NeuroDyn as a tool to probe electrical and molecular properties of functional neural circuits. Neuroscience applications include studying the relationship between molecular properties of neurons and the emergence of different spike patterns or different brain behaviors. Clinical applications include studying and predicting effects of neuromodulators or neurodegenerative diseases on ion channel kinetics.

  3. Numerical investigation on effect of riser diameter and inclination on system parameters in a two-phase closed loop thermosyphon solar water heater

    International Nuclear Information System (INIS)

    Aung, Nay Zar; Li, Songjing

    2013-01-01

    Highlights: • Optimum inclination for maximum heat flux changes with latitude of location. • Optimum inclination for maximum heat flux also changes local solar time. • Maximum flow rate increases with increasing of riser tube size. • Maximum mass flow rate is obtained at different inclinations for different risers. • Length of two-phase region depends on inclination angles but not riser tube size. - Abstract: In this work, the effect of riser diameter and its inclination angle on system parameters in a two-phase closed loop thermosyphon solar water heater has been numerically investigated. Here, receivable heat flux by the collector, circulating mass flow rate, driving pressure, total pressure drop, heat transfer coefficient in risers and collector efficiency are defined as system parameters. For this aim, a model of two-phase thermosyphon solar water heater that is acceptable for various inclinations is presented and variations of riser diameter and inclination are considered. The riser tube size is varied from 1.25 cm to 2.5 cm with inclination range 2–75°. The system absolute pressure is set as 3567 Pa and water is chosen as working fluid. The results show that higher inclination angle is required for higher latitude location to obtain maximum solar heat flux. At local solar noon of 21.996 north latitude, the optimum inclination angle increases in the range of 24–44° with increasing of riser diameter giving maximum circulating mass flow rate from 0.02288 kg/s to 0.03876 kg/s. The longer two-phase heat transfer characteristics can be obtained at smaller inclination angles and mass flow rate for all riser tube sizes. Therefore, it is observed that the optimum inclination angles and diameters for solar heat flux, circulating mass flow rate and heat transfer coefficient in two-phase thermosyphon systemdo not coincide. From this work, better understanding and useful information are provided for constructing two-phase thermosyphon solar heaters

  4. Engineered biomaterial and biophysical stimulation as combinatorial strategies to address prosthetic infection by pathogenic bacteria.

    Science.gov (United States)

    Boda, Sunil Kumar; Basu, Bikramjit

    2017-10-01

    A plethora of antimicrobial strategies are being developed to address prosthetic infection. The currently available methods for implant infection treatment include the use of antibiotics and revision surgery. Among the bacterial strains, Staphylococcus species pose significant challenges particularly, with regard to hospital acquired infections. In order to combat such life threatening infectious diseases, researchers have developed implantable biomaterials incorporating nanoparticles, antimicrobial reinforcements, surface coatings, slippery/non-adhesive and contact killing surfaces. This review discusses a few of the biomaterial and biophysical antimicrobial strategies, which are in the developmental stage and actively being pursued by several research groups. The clinical efficacy of biophysical stimulation methods such as ultrasound, electric and magnetic field treatments against prosthetic infection depends critically on the stimulation protocol and parameters of the treatment modality. A common thread among the three biophysical stimulation methods is the mechanism of bactericidal action, which is centered on biophysical rupture of bacterial membranes, the generation of reactive oxygen species (ROS) and bacterial membrane depolarization evoked by the interference of essential ion-transport. Although the extent of antimicrobial effect, normally achieved through biophysical stimulation protocol is insufficient to warrant therapeutic application, a combination of antibiotic/ROS inducing agents and biophysical stimulation methods can elicit a clinically relevant reduction in viable bacterial numbers. In this review, we present a detailed account of both the biomaterial and biophysical approaches for achieving maximum bacterial inactivation. Summarizing, the biophysical stimulation methods in a combinatorial manner with material based strategies can be a more potent solution to control bacterial infections. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B

  5. A study on some welfare-related parameters of hDAF transgenic pigs when compared with their conventional close relatives.

    Science.gov (United States)

    Martelli, G; Sardi, L; Stancampiano, L; Govoni, N; Zannoni, A; Nannoni, E; Forni, M; Bacci, M L

    2014-05-01

    Pigs are increasingly used in medical research as transgenic laboratory animals; however, little knowledge is presently available concerning their welfare assessment. The aim of the present study was to investigate some welfare-related parameters of transgenic pigs intended for xenotrasplantation (human decay-accelerating factor (hDAF)) when compared with their conventional (i.e. not transgenic) close relatives (full sibs and half sibs). A total of 14 Large White female transgenic pigs and 10 female non-transgenic (conventional) pigs from four litters were used. All pigs were from the same conventional boar, donor of the semen treated for sperm-mediated gene transfer. During the experiment, BW ranged from 50 to about 80 kg and pigs were weighed at the beginning and at the end of the experiment. Animals were subjected to a set of behavioural tests: a human approach test (HAT), a novel object test (NOT) and an open-door test (ODT). Food preferences were tested through the offer of different foods (banana, apple, carrot, cracker and lemon). During a 4-day period, pigs were diurnally videotaped to study the prevalence of the different behaviours and social interactions (aggressive and non-aggressive interactions). At the end of the trial, cortisol level had been assessed on bristles. No significant differences (P>0.05) were observed between hDAF transgenic and conventional pigs with respect to growth traits, reactivity towards unexpected situations (HAT, NOT, ODT), food preferences, main behavioural traits, social interactions and hair cortisol.

  6. Mapeamento e quantificação de parâmetros biofísicos e radiação líquida em área de algodoeiro irrigado Mapping and quantification of biophysical parameters and net radiation over irrigated cotton fields

    Directory of Open Access Journals (Sweden)

    Valéria Peixoto Borges

    2010-04-01

    Full Text Available O sensoriamento remoto tem se mostrado eficaz na avaliação de fluxos de energia e de propriedades biofísicas de superfícies vegetadas em escala regional. No presente trabalho, utilizou-se o algoritmo SEBAL - Surface Energy Balance Algorithm for Land e imagens TM - Landsat 5 para mapeamento e quantificação do albedo (α, NDVI, temperatura da superfície (Ts e radiação líquida (Rn em área de algodão irrigado por pivô central, na Fazenda Busato (13,25º S; 43,42º W; 436 m, município de Bom Jesus da Lapa, Bahia. Seis imagens de céu limpo ao longo do período da cultura (janeiro a agosto de 2007 e os respectivos dados meteorológicos foram utilizados para implementação do algoritmo. Após o processamento digital das imagens, verificou-se nítida relação dos parâmetros α, Ts e NDVI com o desenvolvimento da cultura. Os menores valores de α (10 a 20% e Ts (0,75 ocorreram na fase de máxima cobertura do solo. A radiação líquida (Rn diminuiu progressivamente com o tempo, influenciada, principalmente, pela diminuição da radiação solar incidente com o aumento do ângulo zenital. Os valores de Rn variaram de 430 W m-2 a 700 W m-2 nos pivos cultivados. A técnica de sensoriamento empregada capturou de forma nítida a variabilidade temporal e espacial de Rn e dos parâmetros biofísicos, cujos valores encontrados são compatíveis com os reportados na literatura para a mesma cultura sob regime de irrigação.Remote sensing is currently an important tool for evaluation of net radiation and biophysical parameters over vegetated surfaces on a regional scale. In this research, the SEBAL - Surface Energy Balance Algorithm for Land and TM - Landsat 5 images were used to map and quantify the albedo (α, NDVI, surface temperature (Ts and net radiation (Rn of center-pivot irrigated cotton fields in the Busato Farm (13.25º S; 43.42º W; 436 m asl, western of State of Bahia, Brazil. Images from six clear-sky days during the cropping season

  7. Biophysical Regulation of Vascular Differentiation and Assembly

    CERN Document Server

    Gerecht, Sharon

    2011-01-01

    The ability to grow stem cells in the laboratory and to guide their maturation to functional cells allows us to study the underlying mechanisms that govern vasculature differentiation and assembly in health and disease. Accumulating evidence suggests that early stages of vascular growth are exquisitely tuned by biophysical cues from the microenvironment, yet the scientific understanding of such cellular environments is still in its infancy. Comprehending these processes sufficiently to manipulate them would pave the way to controlling blood vessel growth in therapeutic applications. This book assembles the works and views of experts from various disciplines to provide a unique perspective on how different aspects of its microenvironment regulate the differentiation and assembly of the vasculature. In particular, it describes recent efforts to exploit modern engineering techniques to study and manipulate various biophysical cues. Biophysical Regulation of Vascular Differentiation and Assembly provides an inter...

  8. Biophysical regulation of stem cell differentiation.

    Science.gov (United States)

    Govey, Peter M; Loiselle, Alayna E; Donahue, Henry J

    2013-06-01

    Bone adaptation to its mechanical environment, from embryonic through adult life, is thought to be the product of increased osteoblastic differentiation from mesenchymal stem cells. In parallel with tissue-scale loading, these heterogeneous populations of multipotent stem cells are subject to a variety of biophysical cues within their native microenvironments. Bone marrow-derived mesenchymal stem cells-the most broadly studied source of osteoblastic progenitors-undergo osteoblastic differentiation in vitro in response to biophysical signals, including hydrostatic pressure, fluid flow and accompanying shear stress, substrate strain and stiffness, substrate topography, and electromagnetic fields. Furthermore, stem cells may be subject to indirect regulation by mechano-sensing osteocytes positioned to more readily detect these same loading-induced signals within the bone matrix. Such paracrine and juxtacrine regulation of differentiation by osteocytes occurs in vitro. Further studies are needed to confirm both direct and indirect mechanisms of biophysical regulation within the in vivo stem cell niche.

  9. Biophysical shunt theory for neuropsychopathology: Part I.

    Science.gov (United States)

    Naisberg, Y; Avnon, M; Weizman, A

    1995-11-01

    We present a new model of the origin of schizophrenia based on biophysical ionic shunts in neuronal (electrical) pathways. Microstructural and molecular evidence is presented for the way in which changes in the neuronal membrane ionic channels may facilitate membrane property rearrangement, leading to a change in the density and composition of the ion channel charge which in turn causes a change in ionic flow orientation and distribution. We suggest that, under abnormal conditions, ionic flow shunts are created which redirect the biophysical collateral neuronal (electrical) pathways, resulting in psychiatric signs and symptoms. This model is complementary to the biological basis of schizophrenia.

  10. Global energy modeling - A biophysical approach

    Energy Technology Data Exchange (ETDEWEB)

    Dale, Michael

    2010-09-15

    This paper contrasts the standard economic approach to energy modelling with energy models using a biophysical approach. Neither of these approaches includes changing energy-returns-on-investment (EROI) due to declining resource quality or the capital intensive nature of renewable energy sources. Both of these factors will become increasingly important in the future. An extension to the biophysical approach is outlined which encompasses a dynamic EROI function that explicitly incorporates technological learning. The model is used to explore several scenarios of long-term future energy supply especially concerning the global transition to renewable energy sources in the quest for a sustainable energy system.

  11. Biophysical Evaluation of SonoSteam®:

    DEFF Research Database (Denmark)

    Andersen, Ann Zahle; Duelund, Lars; Brewer, Jonathan R.

    and safety evaluations. Our results show that there are no contradictions between data obtained by either approach. However, the biophysical methods draw a much more nuanced picture of the effects and efficiency of the investigated decontamination method, revealing e.g. an exponential dose/response...... relationship between SonoSteam treatment time and changes in collagen I, and a depth dependency in bacterial reduction, which points toward CFU counts overestimating total bacterial reduction. In conclusion the biophysical methods provide a less biased, reproducible and highly detailed system description...

  12. Biophysical models in radiation oncology

    International Nuclear Information System (INIS)

    Cohen, L.

    1984-01-01

    The paper examines and describes dose-time relationships in clinical radiation oncology. Realistic models and parameters for specific tissues, organs, and tumor types are discussed in order to solve difficult problems which arise in radiation oncology. The computer programs presented were written to: derive parameters from experimental and clinical data; plot normal- and tumor-cell survival curves; generate iso-effect tables of tumor-curative doses; identify alternative, equally effective procedures for fraction numbers and treatment times; determine whether a proposed course of treatment is safe and adequate, and what adjustments are needed should results suggest that the procedure is unsafe or inadequate; combine the physical isodose distribution with computed cellular surviving fractions for the tumor and all normal tissues traversed by the beam, estimating the risks of recurrence or complications at various points in the irradiated volume, and adjusting the treatment plan and fractionation scheme to minimize these risks

  13. Quantum-Sequencing: Biophysics of quantum tunneling through nucleic acids

    Science.gov (United States)

    Casamada Ribot, Josep; Chatterjee, Anushree; Nagpal, Prashant

    2014-03-01

    Tunneling microscopy and spectroscopy has extensively been used in physical surface sciences to study quantum tunneling to measure electronic local density of states of nanomaterials and to characterize adsorbed species. Quantum-Sequencing (Q-Seq) is a new method based on tunneling microscopy for electronic sequencing of single molecule of nucleic acids. A major goal of third-generation sequencing technologies is to develop a fast, reliable, enzyme-free single-molecule sequencing method. Here, we present the unique ``electronic fingerprints'' for all nucleotides on DNA and RNA using Q-Seq along their intrinsic biophysical parameters. We have analyzed tunneling spectra for the nucleotides at different pH conditions and analyzed the HOMO, LUMO and energy gap for all of them. In addition we show a number of biophysical parameters to further characterize all nucleobases (electron and hole transition voltage and energy barriers). These results highlight the robustness of Q-Seq as a technique for next-generation sequencing.

  14. Biophysical aspects of using liposomes as delivery vehicles.

    Science.gov (United States)

    Ulrich, Anne S

    2002-04-01

    Liposomes are used as biocompatible carriers of drugs, peptides, proteins, plasmic DNA, antisense oligonucleotides or ribozymes, for pharmaceutical, cosmetic, and biochemical purposes. The enormous versatility in particle size and in the physical parameters of the lipids affords an attractive potential for constructing tailor-made vehicles for a wide range of applications. Some of the recent literature will be reviewed here and presented from a biophysical point of view, thus providing a background for the more specialized articles in this special issue on liposome technology. Different properties (size, colloidal behavior, phase transitions, and polymorphism) of diverse lipid formulations (liposomes, lipoplexes, cubic phases, emulsions, and solid lipid nanoparticles) for distinct applications (parenteral, transdermal, pulmonary, and oral administration) will be rationalized in terms of common structural, thermodynamic and kinetic parameters of the lipids. This general biophysical basis helps to understand pharmaceutically relevant aspects such as liposome stability during storage and towards serum, the biodistribution and specific targeting of cargo, and how to trigger drug release and membrane fusion. Methods for the preparation and characterization of liposomal formulations in vitro will be outlined, too.

  15. Biophysical aspects of cancer - Electromagnetic mechanism

    Czech Academy of Sciences Publication Activity Database

    Pokorný, Jiří; Hašek, Jiří; Vaniš, Jan; Jelínek, František

    2008-01-01

    Roč. 46, č. 5 (2008), s. 310-321 ISSN 0019-5189 Institutional research plan: CEZ:AV0Z20670512; CEZ:AV0Z50200510 Keywords : Electromagnetic Fields * Biophysics * Cancer Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.599, year: 2008

  16. Biophysics of Hair Cell Sensory Systems

    NARCIS (Netherlands)

    Duifhuis, Hendrikus; Horst, Johannes; van Dijk, Pim; van Netten, Sietse

    1993-01-01

    The last decade revealed to auditory researchers that hair cells can not only detect and process mechanical energy, but are also able to produce it. Thanks to the active hair cell, ears can produce otoacoustic emissions. This book gives the newest insights into the biophysics and physiology of

  17. Analysis of the influence of design parameters of vertically-closed track conveyor with suspended belt and distributed drive on the technical specifications

    Directory of Open Access Journals (Sweden)

    Tolkachev E.N.

    2016-12-01

    Full Text Available Using the basic design of the conveyor with suspended belt and distributed drive, a series of numerical calcu-lations was performed. As a result, the influence of design parameters of vertical loop route on the main tech-nical parameters of the conveyor was established. Recommendations on the choice of rational parameters were formulated.

  18. Biophysical characteristics reveal neural stem cell differentiation potential.

    Directory of Open Access Journals (Sweden)

    Fatima H Labeed

    Full Text Available Distinguishing human neural stem/progenitor cell (huNSPC populations that will predominantly generate neurons from those that produce glia is currently hampered by a lack of sufficient cell type-specific surface markers predictive of fate potential. This limits investigation of lineage-biased progenitors and their potential use as therapeutic agents. A live-cell biophysical and label-free measure of fate potential would solve this problem by obviating the need for specific cell surface markers.We used dielectrophoresis (DEP to analyze the biophysical, specifically electrophysiological, properties of cortical human and mouse NSPCs that vary in differentiation potential. Our data demonstrate that the electrophysiological property membrane capacitance inversely correlates with the neurogenic potential of NSPCs. Furthermore, as huNSPCs are continually passaged they decrease neuron generation and increase membrane capacitance, confirming that this parameter dynamically predicts and negatively correlates with neurogenic potential. In contrast, differences in membrane conductance between NSPCs do not consistently correlate with the ability of the cells to generate neurons. DEP crossover frequency, which is a quantitative measure of cell behavior in DEP, directly correlates with neuron generation of NSPCs, indicating a potential mechanism to separate stem cells biased to particular differentiated cell fates.We show here that whole cell membrane capacitance, but not membrane conductance, reflects and predicts the neurogenic potential of human and mouse NSPCs. Stem cell biophysical characteristics therefore provide a completely novel and quantitative measure of stem cell fate potential and a label-free means to identify neuron- or glial-biased progenitors.

  19. Structural and biophysical characteristics of human skin in maintaining proper epidermal barrier function

    Directory of Open Access Journals (Sweden)

    Magdalena Boer

    2016-02-01

    Full Text Available The complex structure of human skin and its physicochemical properties turn it into an efficient outermost defence line against exogenous factors, and help maintain homeostasis of the human body. This role is played by the epidermal barrier with its major part – stratum corneum. The condition of the epidermal barrier depends on individual and environmental factors. The most important biophysical parameters characterizing the status of this barrier are the skin pH, epidermal hydration, transepidermal water loss and sebum excretion. The knowledge of biophysical skin processes may be useful for the implementation of prophylactic actions whose aim is to restore the barrier function.

  20. Teste triplo biofísico: um novo parâmetro ultra-sonográfico para prognóstico em gestações iniciais Biophysical triple test: a new ultrasonographic parameter for prognostic evaluation in early pregnancies

    Directory of Open Access Journals (Sweden)

    Joaquim R. M. Coelho

    1999-01-01

    Full Text Available Objetivos: atrasos no desenvolvimento do saco gestacional (SG, no tamanho do botão embrionário (CCN, assim como freqüências cardíacas embrionárias (FCE baixas podem ser considerados fatores de mau prognóstico na evolução da gestação. O objetivo deste trabalho foi avaliar a utilização destes 3 parâmetros em conjunto, o que denominamos Teste Triplo Biofísico (TTB. Metodo: foram avaliadas 35 gestações únicas provenientes de fertilização assistida por injeção intracitoplasmática de espermatozóide (ICSI. Todos os exames de ultra-som foram realizados por um único examinador, após 4-5 semanas da transferência de embriões (6-7 semanas de gestação, com equipamento modelo Synergy da Diasonics, sonda transvaginal de 7,0 MHz. O SG foi medido em seu maior diâmetro transverso, o CCN foi medido no sentido sagital e a FCE pelo modo B-M e Doppler. Na análise estatística foi utilizado o teste de Fisher. Resultados: considerou-se como parâmetros alterados : SG Purpose: it has been demonstrated that delays in gestational sac development, in crown-rump length and low embryonic heart rate could be indicators of poor pregnancy outcome. The purpose was to evaluate the use of these three parameters together, which we named Biophysical Triple Test (BTT. Method: thirty-five singleton pregnancies following IVF treatment with intracytoplasmatic sperm injection (ICSI were studied. All ultrasonographic scans were performed by the same examiner, 4-5 weeks after embryo transference (6-7 week gestation, using a Diasonics equipment, model Synergy, with a 7.0-MHz transvaginal transducer. The gestational sac (GS was measured at the longest transverse diameter; the crown-rump length (CRL was measured at the sagittal plan and the embryonic heart rate (EHR was calculated from frozen B and M-mode and Doppler. The statistical test used was Fisher's test. Results: the following parameters were considered abnormal: GS < 15.4 mm, CRL < 3.9 mm, EHR < 100

  1. Cellular normoxic biophysical markers of hydroxyurea treatment in sickle cell disease.

    Science.gov (United States)

    Hosseini, Poorya; Abidi, Sabia Z; Du, E; Papageorgiou, Dimitrios P; Choi, Youngwoon; Park, YongKeun; Higgins, John M; Kato, Gregory J; Suresh, Subra; Dao, Ming; Yaqoob, Zahid; So, Peter T C

    2016-08-23

    Hydroxyurea (HU) has been used clinically to reduce the frequency of painful crisis and the need for blood transfusion in sickle cell disease (SCD) patients. However, the mechanisms underlying such beneficial effects of HU treatment are still not fully understood. Studies have indicated a weak correlation between clinical outcome and molecular markers, and the scientific quest to develop companion biophysical markers have mostly targeted studies of blood properties under hypoxia. Using a common-path interferometric technique, we measure biomechanical and morphological properties of individual red blood cells in SCD patients as a function of cell density, and investigate the correlation of these biophysical properties with drug intake as well as other clinically measured parameters. Our results show that patient-specific HU effects on the cellular biophysical properties are detectable at normoxia, and that these properties are strongly correlated with the clinically measured mean cellular volume rather than fetal hemoglobin level.

  2. EFFECTS OF ACOUSTIC STIMULATION ON BIOPHYSICAL PROFILE TESTING TIME

    Directory of Open Access Journals (Sweden)

    M. Pourissa

    2008-04-01

    Full Text Available Biophysical profile (BPP test is the most commonly used antenatal test of fetal well-being. Purpose of this study is determining the influence of acoustic stimulation (AS on BPP testing time. About 55 pregnant women at 35 to 42 weeks who referred to department of Obstetric & Gynecology at university of medical sciences, Tabriz, Iran, were selected randomly. We used abdominal ultrasound guidance to place buzzer like device with power of 110 dB at the skin surface of the maternal abdomen, close to the fetal head. BPP test performed and BPP mean testing time calculated before and after AS. Data compared and analyzed by paired t-test. The results showed that fetal AS reduces the overall mean testing time from 24 minutes to 5 minutes. This clinical application can be helpful in busy clinics when rapid assessment of fetal health is required.

  3. Biophysical synaptic dynamics in an analog VLSI network of Hodgkin-Huxley neurons.

    Science.gov (United States)

    Yu, Theodore; Cauwenberghs, Gert

    2009-01-01

    We study synaptic dynamics in a biophysical network of four coupled spiking neurons implemented in an analog VLSI silicon microchip. The four neurons implement a generalized Hodgkin-Huxley model with individually configurable rate-based kinetics of opening and closing of Na+ and K+ ion channels. The twelve synapses implement a rate-based first-order kinetic model of neurotransmitter and receptor dynamics, accounting for NMDA and non-NMDA type chemical synapses. The implemented models on the chip are fully configurable by 384 parameters accounting for conductances, reversal potentials, and pre/post-synaptic voltage-dependence of the channel kinetics. We describe the models and present experimental results from the chip characterizing single neuron dynamics, single synapse dynamics, and multi-neuron network dynamics showing phase-locking behavior as a function of synaptic coupling strength. The 3mm x 3mm microchip consumes 1.29 mW power making it promising for applications including neuromorphic modeling and neural prostheses.

  4. Handbook of Single-Molecule Biophysics

    CERN Document Server

    Hinterdorfer, Peter

    2009-01-01

    The last decade has seen the development of a number of novel biophysical methods that allow the manipulation and study of individual biomolecules. The ability to monitor biological processes at this fundamental level of sensitivity has given rise to an improved understanding of the underlying molecular mechanisms. Through the removal of ensemble averaging, distributions and fluctuations of molecular properties can be characterized, transient intermediates identified, and catalytic mechanisms elucidated. By applying forces on biomolecules while monitoring their activity, important information can be obtained on how proteins couple function to structure. The Handbook of Single-Molecule Biophysics provides an introduction to these techniques and presents an extensive discussion of the new biological insights obtained from them. Coverage includes: Experimental techniques to monitor and manipulate individual biomolecules The use of single-molecule techniques in super-resolution and functional imaging Single-molec...

  5. Biophysical behavior of Scomberoides commersonianus skin collagen.

    Science.gov (United States)

    Kolli, Nagamalleswari; Joseph, K Thomas; Ramasami, T

    2002-06-01

    Some biophysical characteristics of the skin collagen from Scomberoides commersonianus were measured and compared to those of rat tail tendon. Stress-strain data indicate that the strain at break as well as the tensile strength of the fish skin without scales increased significantly. The maximum tension in case of rat skin is at least a factor of two higher than that observed in fish skin. The much lower hydrothermal isometric tension measurements observed in fish skin are attributable to a lesser number of heat stable crosslinks. Stress relaxation measurements in the fish skin indicate that more than one relaxation process may be involved in the stabilization of collagenous matrix. The observed differences in the biophysical behavior of fish skin may well arise from combination of changes in extent of hydroxylation of proline in collagen synthesis, hydrogen bond network and fibril orientation as compared to rat tail tendon.

  6. Biophysics and the Challenges of Emerging Threats

    CERN Document Server

    Puglisi, Joseph D

    2009-01-01

    This volume is a collection of articles from the proceedings of the International School of Structural Biology and Magnetic Resonance 8th Course: Biophysics and the Challenges of Emerging Threats. This NATO Advance Study Institute (ASI) was held in Erice at the Ettore Majorana Foundation and Centre for Scientific Culture on 19 through 30 June 2007. The ASI brought together a diverse group of experts who bridged the fields of virology and biology, biophysics, chemistry and physics. Prominent lecturers and students from around the world representant a total of 24 countries participated in the NATO ASI organized by Professors Joseph Puglisi (Stanford University, USA) and Alexander Arseniev (Moscow, RU). The central hypothesis underlying this ASI was that interdisciplinary research, merging principles of physics, chemistry and biology, can drive new discovery in detecting and fighting bioterrorism agents, lead to cleaner environments, and help propel development in NATO partner countries. The ASI merged the relat...

  7. Cystic fibrosis transmembrane conductance regulator is correlated closely with sperm progressive motility and normal morphology in healthy and fertile men with normal sperm parameters.

    Science.gov (United States)

    Jiang, L-Y; Shan, J-J; Tong, X-M; Zhu, H-Y; Yang, L-Y; Zheng, Q; Luo, Y; Shi, Q-X; Zhang, S-Y

    2014-10-01

    Cystic fibrosis transmembrane conductance regulator (CFTR) has been demonstrated to be expressed in mature spermatozoa and correlated with sperm quality. Sperm CFTR expression in fertile men is higher than that in infertile men suffering from teratospermia, asthenoteratospermia, asthenospermia and oligospermia, but it is unknown whether CFTR is correlated with sperm parameters when sperm parameters are normal. In this study, 282 healthy and fertile men with normal semen parameters were classified into three age groups, group (I): age group of 20-29 years (98 cases, 27.1 ± 6.2), group (II): age group of 30-39 years (142 cases, 33.7 ± 2.6) and group (III): age group of more than or equal to 40 years (42 cases, 44.1 ± 4.6). Sperm concentration, total count and progressive motility were analysed by computer-assisted sperm analysis. Sperm morphology was analysed by modified Papanicolaou staining. Sperm CFTR expression was conducted by indirect immunofluorescence staining. There was a significant positive correlation (P sperm progressive motility (r = 0.221) and normal morphology (r = 0.202), but there were no correlations between sperm CFTR expression and semen volume, sperm concentration, sperm total count as well as male age (P > 0.05). Our findings show that CFTR expression is associated with sperm progressive motility and normal morphology in healthy and fertile men with normal sperm parameters, but not associated with the number of spermatozoa and male age. © 2013 Blackwell Verlag GmbH.

  8. Biophysical and structural considerations for protein sequence evolution

    Directory of Open Access Journals (Sweden)

    Grahnen Johan A

    2011-12-01

    Full Text Available Abstract Background Protein sequence evolution is constrained by the biophysics of folding and function, causing interdependence between interacting sites in the sequence. However, current site-independent models of sequence evolutions do not take this into account. Recent attempts to integrate the influence of structure and biophysics into phylogenetic models via statistical/informational approaches have not resulted in expected improvements in model performance. This suggests that further innovations are needed for progress in this field. Results Here we develop a coarse-grained physics-based model of protein folding and binding function, and compare it to a popular informational model. We find that both models violate the assumption of the native sequence being close to a thermodynamic optimum, causing directional selection away from the native state. Sampling and simulation show that the physics-based model is more specific for fold-defining interactions that vary less among residue type. The informational model diffuses further in sequence space with fewer barriers and tends to provide less support for an invariant sites model, although amino acid substitutions are generally conservative. Both approaches produce sequences with natural features like dN/dS Conclusions Simple coarse-grained models of protein folding can describe some natural features of evolving proteins but are currently not accurate enough to use in evolutionary inference. This is partly due to improper packing of the hydrophobic core. We suggest possible improvements on the representation of structure, folding energy, and binding function, as regards both native and non-native conformations, and describe a large number of possible applications for such a model.

  9. Biophysical controls on soil respiration in the dominant patch types of an old-growth, mixed-conifer forest

    Science.gov (United States)

    Siyan Ma; Jiquan Chen; John R. Butnor; Malcolm North; Eugénie S. Euskirchen; Brian Oakley

    2005-01-01

    Little is known about biophysical controls on soil respiration in California's Sierra Nevada old-growth, mixed-conifer forests. Using portable and automated soil respiration sampling units, we measured soil respiration rate (SRR) in three dominant patch types: closed canopy (CC), ceanothus-dominated patches (CECO), and open canopy (OC). SRR varied significantly...

  10. Biophysical EPR Studies Applied to Membrane Proteins

    Science.gov (United States)

    Sahu, Indra D; Lorigan, Gary A

    2015-01-01

    Membrane proteins are very important in controlling bioenergetics, functional activity, and initializing signal pathways in a wide variety of complicated biological systems. They also represent approximately 50% of the potential drug targets. EPR spectroscopy is a very popular and powerful biophysical tool that is used to study the structural and dynamic properties of membrane proteins. In this article, a basic overview of the most commonly used EPR techniques and examples of recent applications to answer pertinent structural and dynamic related questions on membrane protein systems will be presented. PMID:26855825

  11. Synchrotron radiation applications in biophysics and medicine

    International Nuclear Information System (INIS)

    Burattini, E.

    1985-01-01

    The peculiar properties of synchrotron radiation are briefly summarized. A short review on the possible applications of synchrotron radiation in two important fields like Biophysics and Medicine is presented. Details are given on experiments both in progress and carried out in many synchrotron radiation facilities, all over the world, using different techniques like X-ray absorption and fluorescence spectroscopy, X-ray fluorescence microanalysis, X-ray microscopy and digital subtraction angiography. Some news about the photon-activation therapy are briefly reported too

  12. Biophysical processes in the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Mc; Murtugudde, R.; Vialard, J.; Vinayachandran, P.N.; Wiggert, J.D.; Hood, R.R.; Shankar, D.; Shetye, S.R.

    Ocean Biogeochemical Processes and Ecological Variability Geophysical Monograph Series 185 Copyright 200� by the American Geophysical Union. 10.102�/2008GM000768 Biophysical Processes in the Indian Ocean J. P. McCreary, 1 R. Murtugudde, 2 J. Vialard, 3...) also plots the upper-layer thickness, h 1 , from the model of McCreary et al. [1��3] (hereinafter referred to as MKM); h 1 simulates the structure of the top of the actual thermocline reasonably well, except that it is somewhat too thin from 5...

  13. A mathematical approach to protein biophysics

    CERN Document Server

    Scott, L Ridgway

    2017-01-01

    This book explores quantitative aspects of protein biophysics and attempts to delineate certain rules of molecular behavior that make atomic scale objects behave in a digital way.  This book will help readers to understand how certain biological systems involving proteins function as digital information systems despite the fact that underlying processes are analog in nature. The in-depth explanation of proteins from a quantitative point of view and the variety of level of exercises (including physical experiments) at the end of each chapter will appeal to graduate and senior undergraduate students in mathematics, computer science, mechanical engineering, and physics, wanting to learn about the biophysics of proteins.  L. Ridgway Scott has been Professor of Computer Science and of Mathematics at the University of Chicago since 1998, and the Louis Block Professor since 2001.  He obtained a B.S. degree (Magna Cum Laude) from Tulane University in 1969 and a PhD degree in Mathematics from the Massachusetts Ins...

  14. Apocynin: Chemical and Biophysical Properties of a NADPH Oxidase Inhibitor

    Directory of Open Access Journals (Sweden)

    Valdecir F. Ximenes

    2013-03-01

    Full Text Available Apocynin is the most employed inhibitor of NADPH oxidase (NOX, a multienzymatic complex capable of catalyzing the one-electron reduction of molecular oxygen to the superoxide anion. Despite controversies about its selectivity, apocynin has been used as one of the most promising drugs in experimental models of inflammatory and neurodegenerative diseases. Here, we aimed to study the chemical and biophysical properties of apocynin. The oxidation potential was determined by cyclic voltammetry (Epa = 0.76V, the hydrophobicity index was calculated (logP = 0.83 and the molar absorption coefficient was determined (e275nm = 1.1 × 104 M−1 cm−1. Apocynin was a weak free radical scavenger (as measured using the DPPH, peroxyl radical and nitric oxide assays when compared to protocatechuic acid, used here as a reference antioxidant. On the other hand, apocynin was more effective than protocatechuic acid as scavenger of the non-radical species hypochlorous acid. Apocynin reacted promptly with the non-radical reactive species H2O2 only in the presence of peroxidase. This finding is relevant, since it represents a new pathway for depleting H2O2 in cellular experimental models, besides the direct inhibition of NADPH oxidase. This could be relevant for its application as an inhibitor of NOX4, since this isoform produces H2O2 and not superoxide anion. The binding parameters calculated by fluorescence quenching showed that apocynin binds to human serum albumin (HSA with a binding affinity of 2.19 × 104 M−1. The association did not alter the secondary and tertiary structure of HSA, as verified by synchronous fluorescence and circular dichroism. The displacement of fluorescent probes suggested that apocynin binds to site I and site II of HSA. Considering the current biomedical applications of this phytochemical, the dissemination of these chemical and biophysical properties can be very helpful for scientists and physicians interested in the use of apocynin.

  15. An investigation of the effects of experimental parameters on the closed-loop control of photoionization/dissociation processes in acetophenone

    Science.gov (United States)

    Graham, Paul; Menkir, Getahun; Levis, Robert J.

    2003-06-01

    The photodissociation channels of acetophenone (C 6H 5)CO(CH 3), can be controlled by the use of tailored strong-field laser pulses together with a feedback loop incorporating an adaptive algorithm. This optimal control strategy is used to selectively cleave either the OCCH 3 or OCC 6H 5 bonds, monitored by detecting either mass 105 or 77, respectively. Varying the pulse chirp and duration prior to optimization is shown to affect the dynamic range of control. We show that it is possible to decrease the search space by limiting the retardance range of the spatial light modulator (SLM), or by decreasing the number of frequency elements manipulated by the SLM, and still achieve a certain degree of control over acetophenone dissociation. Performing consecutive experiments with identical experimental parameters and search criteria reveals that the learning algorithm may find solutions that have the same degree of control (various local solutions), with either similar SLM retardances or markedly different retardances. Comparison of the dynamic range of control between single-parameter optimizations (pulse energy and duration) with the tailored electric field profiles generated by the adaptive algorithm reveals an enhancement in the control of reaction product distributions in the latter scheme.

  16. Biophysical models of larval dispersal in the Benguela Current ...

    African Journals Online (AJOL)

    We synthesise and update results from the suite of biophysical, larval-dispersal models developed in the Benguela Current ecosystem. Biophysical models of larval dispersal use outputs of physical hydrodynamic models as inputs to individual-based models in which biological processes acting during the larval life are ...

  17. Biophysics: for HTS hit validation, chemical lead optimization, and beyond.

    Science.gov (United States)

    Genick, Christine C; Wright, S Kirk

    2017-09-01

    There are many challenges to the drug discovery process, including the complexity of the target, its interactions, and how these factors play a role in causing the disease. Traditionally, biophysics has been used for hit validation and chemical lead optimization. With its increased throughput and sensitivity, biophysics is now being applied earlier in this process to empower target characterization and hit finding. Areas covered: In this article, the authors provide an overview of how biophysics can be utilized to assess the quality of the reagents used in screening assays, to validate potential tool compounds, to test the integrity of screening assays, and to create follow-up strategies for compound characterization. They also briefly discuss the utilization of different biophysical methods in hit validation to help avoid the resource consuming pitfalls caused by the lack of hit overlap between biophysical methods. Expert opinion: The use of biophysics early on in the drug discovery process has proven crucial to identifying and characterizing targets of complex nature. It also has enabled the identification and classification of small molecules which interact in an allosteric or covalent manner with the target. By applying biophysics in this manner and at the early stages of this process, the chances of finding chemical leads with novel mechanisms of action are increased. In the future, focused screens with biophysics as a primary readout will become increasingly common.

  18. Low temperature experiments in radiation biophysics

    International Nuclear Information System (INIS)

    Moan, J.

    1977-01-01

    The reasons for performing experiments in radiation biophysics at low temperatures, whereby electron spectra may be studied, are explained. The phenomenon of phosphorescence spectra observed in frozen aqueous solutions of tryptophan and adenosine is also described. Free radicals play an important part in biological radiation effects and may be studied by ESR spectroscopy. An ESR spectrum of T 1 bacteriophages irradiated dry at 130K is illustrated and discussed. Hydrogen atoms, which give lines on the spectrum, are believed to be those radiation products causing most biological damage in a dry system. Low temperature experiments are of great help in explaining the significance of direct and indirect effects. This is illustrated for the case of trypsin. (JIW)

  19. Microwave Tissue Ablation: Biophysics, Technology and Applications

    Science.gov (United States)

    2010-01-01

    Microwave ablation is an emerging treatment option for many cancers, cardiac arrhythmias and other medical conditions. During treatment, microwaves are applied directly to tissues to produce rapid temperature elevations sufficient to produce immediate coagulative necrosis. The engineering design criteria for each application differ, with individual consideration for factors such as desired ablation zone size, treatment duration, and procedural invasiveness. Recent technological developments in applicator cooling, power control and system optimization for specific applications promise to increase the utilization of microwave ablation in the future. This article will review the basic biophysics of microwave tissue heating, provide an overview of the design and operation of current equipment, and outline areas for future research for microwave ablation. PMID:21175404

  20. Biophysical mechanisms complementing "classical" cell biology.

    Science.gov (United States)

    Funk, Richard H W

    2018-01-01

    This overview addresses phenomena in cell- and molecular biology which are puzzling by their fast and highly coordinated way of organization. Generally, it appears that informative processes probably involved are more on the biophysical than on the classical biochemical side. The coordination problem is explained within the first part of the review by the topic of endogenous electrical phenomena. These are found e.g. in fast tissue organization and reorganization processes like development, wound healing and regeneration. Here, coupling into classical biochemical signaling and reactions can be shown by modern microscopy, electronics and bioinformatics. Further, one can follow the triggered reactions seamlessly via molecular biology till into genetics. Direct observation of intracellular electric processes is very difficult because of e.g. shielding through the cell membrane and damping by other structures. Therefore, we have to rely on photonic and photon - phonon coupling phenomena like molecular vibrations, which are addressed within the second part. Molecules normally possess different charge moieties and thus small electromagnetic (EMF) patterns arise during molecular vibration. These patterns can now be measured best within the optical part of the spectrum - much less in the lower terahertz till kHz and lower Hz part (third part of this review). Finally, EMFs facilitate quantum informative processes in coherent domains of molecular, charge and electron spin motion. This helps to coordinate such manifold and intertwined processes going on within cells, tissues and organs (part 4). Because the phenomena described in part 3 and 4 of the review still await really hard proofs we need concerted efforts and a combination of biophysics, molecular biology and informatics to unravel the described mysteries in "physics of life".

  1. Estimating the biophysical properties of neurons with intracellular calcium dynamics.

    Science.gov (United States)

    Ye, Jingxin; Rozdeba, Paul J; Morone, Uriel I; Daou, Arij; Abarbanel, Henry D I

    2014-06-01

    We investigate the dynamics of a conductance-based neuron model coupled to a model of intracellular calcium uptake and release by the endoplasmic reticulum. The intracellular calcium dynamics occur on a time scale that is orders of magnitude slower than voltage spiking behavior. Coupling these mechanisms sets the stage for the appearance of chaotic dynamics, which we observe within certain ranges of model parameter values. We then explore the question of whether one can, using observed voltage data alone, estimate the states and parameters of the voltage plus calcium (V+Ca) dynamics model. We find the answer is negative. Indeed, we show that voltage plus another observed quantity must be known to allow the estimation to be accurate. We show that observing both the voltage time course V(t) and the intracellular Ca time course will permit accurate estimation, and from the estimated model state, accurate prediction after observations are completed. This sets the stage for how one will be able to use a more detailed model of V+Ca dynamics in neuron activity in the analysis of experimental data on individual neurons as well as functional networks in which the nodes (neurons) have these biophysical properties.

  2. Biophysical insight into the anti-amyloidogenic behavior of taurine.

    Science.gov (United States)

    Chaturvedi, Sumit Kumar; Alam, Parvez; Khan, Javed Masood; Siddiqui, Mohd Khursheed; Kalaiarasan, Ponnusamy; Subbarao, Naidu; Ahmad, Zeeshan; Khan, Rizwan Hasan

    2015-09-01

    In this work, we investigated the inhibitory ability of taurine on the aggregation of Human serum albumin (HSA) and also examined how it controls the kinetic parameters of the aggregation process. We demonstrated the structural alterations in the HSA after binding to the taurine at 65 °C by exploiting various biophysical techniques. UV-vis spectroscopy was used to check the turbidometric changes in the protein. Thioflavin T fluorescence kinetics was subjected to explore kinetic parameters comparing the amyloid formation in the presence of varying concentration of taurine. Further, Congo red binding and ANS binding assays were performed to determine the inhibitory effect of taurine on HSA fibrillation process and surface hydrophobicity modifications occurring before and after the addition of taurine with protein, respectively. Far UV CD and Dynamic Light Scattering (DLS) confirmed that taurine stabilized the protein α-helical structure and formed complex with HSA which is further supported by differential scanning calorimetry (DSC). Moreover, microscopic imaging techniques were also done to analyze the morphology of aggregation formed. Taurine is also capable of altering the cytotoxicity of the proteinaceous aggregates. Molecular docking study also deciphered the possible residues involved in protein and drug interaction. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. High-field 1H NMR microscopy for fundamental biophysical research

    International Nuclear Information System (INIS)

    Haddad, D.

    2003-01-01

    This work has a biophysical background and uses different examples to demonstrate the practical applicability of NMR-Microscopy in the medical and biological sector. Therefore, the different projects are feasibility studies which are used to compare the possibilities and advantages of NMR-Microscopy with other, established examination techniques. In detail, using MR-Microscopy, different living and fixed biological samples have been visualized non-invasively with high spatial resolution. The specific purpose of the studies ranged from the visualization of the invasion of tumor-spheroids into cell aggregates using T2 parameter maps (time constant of the spin-spin relaxation) to the three-dimensional display of the honey bee brain in the intact head capsule and the non-invasive visualization of the anatomy of prenatal dolphins. For all these projects, the non-invasive character of MR-experiments was of utmost importance. The tumor invasion was not to be disturbed by the measurements, the bee brain should be visualized as close to its true natural shape as possible and the examined dolphins represent rare museum specimens which should not be destroyed. The different samples were all imaged with the best possible spatial resolution which was either limited by the necessary signal-to-noise ratio (SNR) or the available scan time. In order to resolve single details and fine structures in the images, it was necessary to optimize the SNR as well as the contrast-to-noise ratio. To guarantee the necessary SNR, the measurements were performed on high field MR-spectrometers with resonance frequencies of 500 and 750 MHz

  4. Biophysical modeling of in vitro and in vivo processes underlying regulated photoprotective mechanism in cyanobacteria.

    Science.gov (United States)

    Shirshin, Evgeny A; Nikonova, Elena E; Kuzminov, Fedor I; Sluchanko, Nikolai N; Elanskaya, Irina V; Gorbunov, Maxim Y; Fadeev, Victor V; Friedrich, Thomas; Maksimov, Eugene G

    2017-09-01

    Non-photochemical quenching (NPQ) is a mechanism responsible for high light tolerance in photosynthetic organisms. In cyanobacteria, NPQ is realized by the interplay between light-harvesting complexes, phycobilisomes (PBs), a light sensor and effector of NPQ, the photoactive orange carotenoid protein (OCP), and the fluorescence recovery protein (FRP). Here, we introduced a biophysical model, which takes into account the whole spectrum of interactions between PBs, OCP, and FRP and describes the experimental PBs fluorescence kinetics, unraveling interaction rate constants between the components involved and their relative concentrations in the cell. We took benefit from the possibility to reconstruct the photoprotection mechanism and its parts in vitro, where most of the parameters could be varied, to develop the model and then applied it to describe the NPQ kinetics in the Synechocystis sp. PCC 6803 mutant lacking photosystems. Our analyses revealed  that while an excess of the OCP over PBs is required to obtain substantial PBs fluorescence quenching in vitro, in vivo the OCP/PBs ratio is less than unity, due to higher local concentration of PBs, which was estimated as ~10 -5 M, compared to in vitro experiments. The analysis of PBs fluorescence recovery on the basis of the generalized model of enzymatic catalysis resulted in determination of the FRP concentration in vivo close to 10% of the OCP concentration. Finally, the possible role of the FRP oligomeric state alteration in the kinetics of PBs fluorescence was shown. This paper provides the most comprehensive model of the OCP-induced PBs fluorescence quenching to date and the results are important for better understanding of the regulatory molecular mechanisms underlying NPQ in cyanobacteria.

  5. The application of multiple biophysical cues to engineer functional neocartilage for treatment of osteoarthritis. Part II: signal transduction.

    Science.gov (United States)

    Brady, Mariea A; Waldman, Stephen D; Ethier, C Ross

    2015-02-01

    The unique mechanoelectrochemical environment of cartilage has motivated researchers to investigate the effect of multiple biophysical cues, including mechanical, magnetic, and electrical stimulation, on chondrocyte biology. It is well established that biophysical stimuli promote chondrocyte proliferation, differentiation, and maturation within "biological windows" of defined dose parameters, including mode, frequency, magnitude, and duration of stimuli (see companion review Part I: Cellular Response). However, the underlying molecular mechanisms and signal transduction pathways activated in response to multiple biophysical stimuli remain to be elucidated. Understanding the mechanisms of biophysical signal transduction will deepen knowledge of tissue organogenesis, remodeling, and regeneration and aiding in the treatment of pathologies such as osteoarthritis. Further, this knowledge will provide the tissue engineer with a potent toolset to manipulate and control cell fate and subsequently develop functional replacement cartilage. The aim of this article is to review chondrocyte signal transduction pathways in response to mechanical, magnetic, and electrical cues. Signal transduction does not occur along a single pathway; rather a number of parallel pathways appear to be activated, with calcium signaling apparently common to all three types of stimuli, though there are different modes of activation. Current tissue engineering strategies, such as the development of "smart" functionalized biomaterials that enable the delivery of growth factors or integration of conjugated nanoparticles, may further benefit from targeting known signal transduction pathways in combination with external biophysical cues.

  6. The application of multiple biophysical cues to engineer functional neocartilage for treatment of osteoarthritis. Part I: cellular response.

    Science.gov (United States)

    Brady, Mariea A; Waldman, Stephen D; Ethier, C Ross

    2015-02-01

    Osteoarthritis (OA) is a complex disease of the joint for which current treatments are unsatisfactory, thus motivating development of tissue engineering (TE)-based therapies. To date, TE strategies have had some success, developing replacement tissue constructs with biochemical properties approaching that of native cartilage. However, poor biomechanical properties and limited postimplantation integration with surrounding tissue are major shortcomings that need to be addressed. Functional tissue engineering strategies that apply physiologically relevant biophysical cues provide a platform to improve TE constructs before implantation. In the previous decade, new experimental and theoretical findings in cartilage biomechanics and electromechanics have emerged, resulting in an increased understanding of the complex interplay of multiple biophysical cues in the extracellular matrix of the tissue. The effect of biophysical stimulation on cartilage, and the resulting chondrocyte-mediated biosynthesis, remodeling, degradation, and repair, has, therefore, been extensively explored by the TE community. This article compares and contrasts the cellular response of chondrocytes to multiple biophysical stimuli, and may be read in conjunction with its companion paper that compares and contrasts the subsequent intracellular signal transduction cascades. Mechanical, magnetic, and electrical stimuli promote proliferation, differentiation, and maturation of chondrocytes within established dose parameters or "biological windows." This knowledge will provide a framework for ongoing studies incorporating multiple biophysical cues in TE functional neocartilage for treatment of OA.

  7. Biophysical Aspects of Radiation Quality. Second Panel Report

    International Nuclear Information System (INIS)

    1968-01-01

    If a living system is exposed to ionizing radiation a sequence of events follows. It starts with the absorption and dissipation of radiation energy, and continues through various physico-chemical and biochemical reactions up to the final biological end point observed. One of the aims of research in quantitative radiation biology is to understand the mechanism of this sequence of actions and to explore the differences in quality of different kinds of radiations. Because of its complexity, progress in this work requires the combined efforts of physicists, biochemists, biologists and physicians. It should, however, be done in very close collaboration rather than in following isolated lines in any one direction. For this reason, and because of the growing importance of the field for almost all applications of ionizing radiations, it was felt desirable to bring together a group of scientists engaged in research on radiation quality who represented a wide range of interests. The first panel on Biophysical Aspects of Radiation Quality, convened by the International Atomic Energy Agency in Vienna and held from 29 March to 2 April 1965, proved to be a successful beginning, stimulating a useful exchange of ideas and information. By this meeting, and the resulting collection of papers, published in 1966 as No. 58 of the Agency's Technical Reports Series, the importance of research on radiation quality was highlighted and the field itself became more clearly defined. The Agency held a second Panel on the same subject in Vienna from 14 to 18 April 1967. This meeting was attended by 18 experts from 10 countries, and representatives from Euratom and WHO. The Czechoslovak Socialist Republic, France, India and Poland were represented for the first time. Fourteen papers were presented and discussed in some detail. It became evident that much progress had been made since the previous meeting in certain areas such as microdosimetry, the dependence of the oxygen effect on radiation

  8. Shape Transformation of the Nuclear Envelope during Closed Mitosis.

    Science.gov (United States)

    Zhu, Qian; Zheng, Fan; Liu, Allen P; Qian, Jin; Fu, Chuanhai; Lin, Yuan

    2016-11-15

    The nuclear envelope (NE) in lower eukaryotes such as Schizosaccharomyces pombe undergoes large morphology changes during closed mitosis. However, which physical parameters are important in governing the shape evolution of the NE, and how defects in the dividing chromosomes/microtubules are reflected in those parameters, are fundamental questions that remain unresolved. In this study, we show that improper separation of chromosomes in genetically deficient cells leads to membrane tethering or asymmetric division in contrast to the formation of two equal-sized daughter nuclei in wild-type cells. We hypothesize that the poleward force is transmitted to the nuclear membrane through its physical contact with the separated sister chromatids at the two spindle poles. A theoretical model is developed to predict the morphology evolution of the NE where key factors such as the work done by the poleward force and bending and surface energies stored in the membrane have been taken into account. Interestingly, the predicted phase diagram, summarizing the dependence of nuclear shape on the size of the load transmission regions, and the pole-to-pole distance versus surface area relationship all quantitatively agree well with our experimental observations, suggesting that this model captures the essential physics involved in closed mitosis. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  9. Estimation efficiency of usage satellite derived and modelled biophysical products for yield forecasting

    Science.gov (United States)

    Kolotii, Andrii; Kussul, Nataliia; Skakun, Sergii; Shelestov, Andrii; Ostapenko, Vadim; Oliinyk, Tamara

    2015-04-01

    Efficient and timely crop monitoring and yield forecasting are important tasks for ensuring of stability and sustainable economic development [1]. As winter crops pay prominent role in agriculture of Ukraine - the main focus of this study is concentrated on winter wheat. In our previous research [2, 3] it was shown that usage of biophysical parameters of crops such as FAPAR (derived from Geoland-2 portal as for SPOT Vegetation data) is far more efficient for crop yield forecasting to NDVI derived from MODIS data - for available data. In our current work efficiency of usage such biophysical parameters as LAI, FAPAR, FCOVER (derived from SPOT Vegetation and PROBA-V data at resolution of 1 km and simulated within WOFOST model) and NDVI product (derived from MODIS) for winter wheat monitoring and yield forecasting is estimated. As the part of crop monitoring workflow (vegetation anomaly detection, vegetation indexes and products analysis) and yield forecasting SPIRITS tool developed by JRC is used. Statistics extraction is done for landcover maps created in SRI within FP-7 SIGMA project. Efficiency of usage satellite based and modelled with WOFOST model biophysical products is estimated. [1] N. Kussul, S. Skakun, A. Shelestov, O. Kussul, "Sensor Web approach to Flood Monitoring and Risk Assessment", in: IGARSS 2013, 21-26 July 2013, Melbourne, Australia, pp. 815-818. [2] F. Kogan, N. Kussul, T. Adamenko, S. Skakun, O. Kravchenko, O. Kryvobok, A. Shelestov, A. Kolotii, O. Kussul, and A. Lavrenyuk, "Winter wheat yield forecasting in Ukraine based on Earth observation, meteorological data and biophysical models," International Journal of Applied Earth Observation and Geoinformation, vol. 23, pp. 192-203, 2013. [3] Kussul O., Kussul N., Skakun S., Kravchenko O., Shelestov A., Kolotii A, "Assessment of relative efficiency of using MODIS data to winter wheat yield forecasting in Ukraine", in: IGARSS 2013, 21-26 July 2013, Melbourne, Australia, pp. 3235 - 3238.

  10. Soil functional types: surveying the biophysical dimensions of soil security

    Science.gov (United States)

    Cécillon, Lauric; Barré, Pierre

    2015-04-01

    Soil is a natural capital that can deliver key ecosystem services (ES) to humans through the realization of a series of soil processes controlling ecosystem functioning. Soil is also a diverse and endangered natural resource. A huge pedodiversity has been described at all scales, which is strongly altered by global change. The multidimensional concept soil security, encompassing biophysical, economic, social, policy and legal frameworks of soils has recently been proposed, recognizing the role of soils in global environmental sustainability challenges. The biophysical dimensions of soil security focus on the functionality of a given soil that can be viewed as the combination of its capability and its condition [1]. Indeed, all soils are not equal in term of functionality. They show different processes, provide different ES to humans and respond specifically to global change. Knowledge of soil functionality in space and time is thus a crucial step towards the achievement soil security. All soil classification systems incorporate some functional information, but soil taxonomy alone cannot fully describe the functioning, limitations, resistance and resilience of soils. Droogers and Bouma [2] introduced functional variants (phenoforms) for each soil type (genoform) so as to fit more closely to soil functionality. However, different genoforms can have the same functionality. As stated by McBratney and colleagues [1], there is a great need of an agreed methodology for defining the reference state of soil functionality. Here, we propose soil functional types (SFT) as a relevant classification system for the biophysical dimensions of soil security. Following the definition of plant functional types widely used in ecology, we define a soil functional type as "a set of soil taxons or phenoforms sharing similar processes (e.g. soil respiration), similar effects on ecosystem functioning (e.g. primary productivity) and similar responses to global change (land-use, management or

  11. Biophysical Approach to Mechanisms of Cancer Prevention and Treatment with Green Tea Catechins.

    Science.gov (United States)

    Suganuma, Masami; Takahashi, Atsushi; Watanabe, Tatsuro; Iida, Keisuke; Matsuzaki, Takahisa; Yoshikawa, Hiroshi Y; Fujiki, Hirota

    2016-11-18

    Green tea catechin and green tea extract are now recognized as non-toxic cancer preventives for humans. We first review our brief historical development of green tea cancer prevention. Based on exciting evidence that green tea catechin, (-)-epigallocatechin gallate (EGCG) in drinking water inhibited lung metastasis of B16 melanoma cells, we and other researchers have studied the inhibitory mechanisms of metastasis with green tea catechins using biomechanical tools, atomic force microscopy (AFM) and microfluidic optical stretcher. Specifically, determination of biophysical properties of cancer cells, low cell stiffness, and high deformability in relation to migration, along with biophysical effects, were studied by treatment with green tea catechins. The study with AFM revealed that low average values of Young's moduli, indicating low cell stiffness, are closely associated with strong potential of cell migration and metastasis for various cancer cells. It is important to note that treatments with EGCG and green tea extract elevated the average values of Young's moduli resulting in increased stiffness (large elasticity) of melanomas and various cancer cells. We discuss here the biophysical basis of multifunctions of green tea catechins and green tea extract leading to beneficial effects for cancer prevention and treatment.

  12. Biophysical Approach to Mechanisms of Cancer Prevention and Treatment with Green Tea Catechins

    Directory of Open Access Journals (Sweden)

    Masami Suganuma

    2016-11-01

    Full Text Available Green tea catechin and green tea extract are now recognized as non-toxic cancer preventives for humans. We first review our brief historical development of green tea cancer prevention. Based on exciting evidence that green tea catechin, (−-epigallocatechin gallate (EGCG in drinking water inhibited lung metastasis of B16 melanoma cells, we and other researchers have studied the inhibitory mechanisms of metastasis with green tea catechins using biomechanical tools, atomic force microscopy (AFM and microfluidic optical stretcher. Specifically, determination of biophysical properties of cancer cells, low cell stiffness, and high deformability in relation to migration, along with biophysical effects, were studied by treatment with green tea catechins. The study with AFM revealed that low average values of Young’s moduli, indicating low cell stiffness, are closely associated with strong potential of cell migration and metastasis for various cancer cells. It is important to note that treatments with EGCG and green tea extract elevated the average values of Young’s moduli resulting in increased stiffness (large elasticity of melanomas and various cancer cells. We discuss here the biophysical basis of multifunctions of green tea catechins and green tea extract leading to beneficial effects for cancer prevention and treatment.

  13. Biophysically realistic minimal model of dopamine neuron

    Science.gov (United States)

    Oprisan, Sorinel

    2008-03-01

    We proposed and studied a new biophysically relevant computational model of dopaminergic neurons. Midbrain dopamine neurons are involved in motivation and the control of movement, and have been implicated in various pathologies such as Parkinson's disease, schizophrenia, and drug abuse. The model we developed is a single-compartment Hodgkin-Huxley (HH)-type parallel conductance membrane model. The model captures the essential mechanisms underlying the slow oscillatory potentials and plateau potential oscillations. The main currents involved are: 1) a voltage-dependent fast calcium current, 2) a small conductance potassium current that is modulated by the cytosolic concentration of calcium, and 3) a slow voltage-activated potassium current. We developed multidimensional bifurcation diagrams and extracted the effective domains of sustained oscillations. The model includes a calcium balance due to the fundamental importance of calcium influx as proved by simultaneous electrophysiological and calcium imaging procedure. Although there are significant evidences to suggest a partially electrogenic calcium pump, all previous models considered only elecrtogenic pumps. We investigated the effect of the electrogenic calcium pump on the bifurcation diagram of the model and compared our findings against the experimental results.

  14. Biophysical and biomathematical adventures in radiobiology

    International Nuclear Information System (INIS)

    Scott, B.R.

    1991-01-01

    Highlights of my biophysical and biomathematical adventures in radiobiology is presented. Early adventures involved developing ''state-vector models'' for specific harmful effects (cell killing, life shortening) of exposure to radiation. More recent adventures led to developing ''hazard-function models'' for predicting biological effects (e.g., cell killing, mutations, tumor induction) of combined exposure to different toxicants. Hazard-function models were also developed for predicting harm to man from exposure to large radiation doses. Major conclusions derived from the modeling adventures are as follows: (1) synergistic effects of different genotoxic agents should not occur at low doses; (2) for exposure of the lung or bone marrow to large doses of photon radiation, low rates of exposure should be better tolerated than high rates; and (3) for some types of radiation (e.g., alpha particles and fission neutrons), moderate doses delivered at a low rate may be more harmful than the same dose given at a high rate. 53 refs., 7 figs

  15. Review of FEWS NET Biophysical Monitoring Requirements

    Science.gov (United States)

    Ross, K. W.; Brown, Molly E.; Verdin, J.; Underwood, L. W.

    2009-01-01

    The Famine Early Warning System Network (FEWS NET) provides monitoring and early warning support to decision makers responsible for responding to famine and food insecurity. FEWS NET transforms satellite remote sensing data into rainfall and vegetation information that can be used by these decision makers. The National Aeronautics and Space Administration has recently funded activities to enhance remote sensing inputs to FEWS NET. To elicit Earth observation requirements, a professional review questionnaire was disseminated to FEWS NET expert end-users: it focused upon operational requirements to determine additional useful remote sensing data and; subsequently, beneficial FEWS NET biophysical supplementary inputs. The review was completed by over 40 experts from around the world, enabling a robust set of professional perspectives to be gathered and analyzed rapidly. Reviewers were asked to evaluate the relative importance of environmental variables and spatio-temporal requirements for Earth science data products, in particular for rainfall and vegetation products. The results showed that spatio-temporal resolution requirements are complex and need to vary according to place, time, and hazard: that high resolution remote sensing products continue to be in demand, and that rainfall and vegetation products were valued as data that provide actionable food security information.

  16. Contribution to researches in biophysics and biology

    International Nuclear Information System (INIS)

    Luccioni, Catherine

    2000-01-01

    In this accreditation to supervise research, the author indicates its curriculum and scientific works which mainly dealt with the different agents used in chemotherapy. Scientific works addressed anti-carcinogenic pharmacology, applied biophysics, and researches in oncology and radiobiology. Current research projects deal with mechanisms of cellular transformation and the implication of the anti-oxidising metabolism and of nucleotide metabolism in cell radio-sensitivity. Teaching and research supervising activities are also indicated. Several articles are proposed in appendix: Average quality factor and dose equivalent meter based on microdosimetry techniques; Activity of thymidylate synthetase, thymidine kinase and galactokinase in primary and xenografted human colorectal cancers in relation to their chromosomal patterns; Nucleotide metabolism in human gliomas, relation to the chromosomal profile; Pyrimidine nucleotide metabolism in human colon carcinomas: comparison of normal tissues, primary tumors and xenografts; Modifications of the antioxidant metabolism during proliferation and differentiation of colon tumours cell lines; Modulation of the antioxidant enzymes, p21 and p53 expression during proliferation and differentiation of human melanoma cell lines; Purine metabolism in 2 human melanoma cell lines, relation with proliferation and differentiation; Radiation-induced changes in nucleotide metabolism of 2 colon cancer cell lines with different radio-sensitivities

  17. Developing spatial biophysical accounting for multiple ecosystem services

    NARCIS (Netherlands)

    Remme, R.P.; Schroter, M.; Hein, L.G.

    2014-01-01

    Ecosystem accounting is receiving increasing interest as a way to systematically monitor the conditions of ecosystems and the ecosystem services they provide. A critical element of ecosystem accounting is understanding spatially explicit flows of ecosystem services. We developed spatial biophysical

  18. Developing a protocol for managing the biophysical condition of a ...

    African Journals Online (AJOL)

    Their function will focus on the overall management of water resources on a ... for the integrated management of the biophysical component of a catchment, with ... and implement a protocol which will combine and integrate the knowledge of ...

  19. Biophysical approach to low back pain: a pilot report

    Czech Academy of Sciences Publication Activity Database

    Foletti, A.; Pokorný, Jiří

    2015-01-01

    Roč. 34, č. 2 (2015), s. 156-159 ISSN 1536-8378 Institutional support: RVO:67985882 Keywords : Bioelectromagnetic medicine * Biophysical therapy * Coherence domains Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.208, year: 2015

  20. Biophysical Influence of Airborne Carbon Nanomaterials on Natural Pulmonary Surfactant

    OpenAIRE

    Valle, Russell P.; Wu, Tony; Zuo, Yi Y.

    2015-01-01

    Inhalation of nanoparticles (NP), including lightweight airborne carbonaceous nanomaterials (CNM), poses a direct and systemic health threat to those who handle them. Inhaled NP penetrate deep pulmonary structures in which they first interact with the pulmonary surfactant (PS) lining at the alveolar air–water interface. In spite of many research efforts, there is a gap of knowledge between in vitro biophysical study and in vivo inhalation toxicology since all existing biophysical models handl...

  1. The relationship between fetal biophysical profile and cord blood PH

    Directory of Open Access Journals (Sweden)

    Valadan M

    2009-02-01

    Full Text Available "nBackground: The Biophysical Profile (BPP is a noninvasive test that predicts the presence or absence of fetal asphyxia and, ultimately, the risk of fetal death in the antenatal period. Intervention on the basis of an abnormal biophysical profile result has been reported to yield a significant reduction in prenatal mortality, and an association exists between biophysical profile scoring and a decreased cerebral palsy rate in a given population. The BPP evaluates five characteristics: fetal movement, tone, breathing, heart reactivity, and amniotic fluid (AF volume estimation. The purpose of study was to determine whether there are different degree of acidosis at which the biophysical activity (acute marker are affected. "nMethods: In a prospective study of 140 patients undergoing cesarean section before onset of labor, the fetal biophysical profile was performed 24h before the time of cesarean and was matched with cord arterial PH that was obtained from a cord segment (10-20cm that was double clamped after delivery of newborn. (using cord arterial PH less than 7.20 for the diagnosis of acidosis. "nResults: The fetal biophysical profile was found to have a significant relationship with umbilical blood PH. The sensitivity, specificity, positive predictive value, negative predictive value of fetal biophysical profile score were: 88.9%, 88.6%, 50%, 98.1%. "nConclusion: The first manifestations of fetal acidosis are nonreactive nonstress testing and fetal breathing loss; in advanced acidemia fetal movements and fetal tone are compromised. A protocol of antepartum fetal evaluation is suggested based upon the individual biophysical components rather than the score alone.

  2. Biophysics of Human Hair Structural, Nanomechanical, and Nanotribological Studies

    CERN Document Server

    Bhushan, Bharat

    2010-01-01

    This book presents the biophysics of hair. It deals with the structure of hair, its mechanical properties, the nanomechanical characterization, tensile deformation, tribological characterization, the thickness distribution and binding interactions on hair surface. Another important topic of the book is the health of hair, human hair and skin, hair care, cleaning and conditioning treatments and damaging processes. It is the first book on the biophysical properties of hair.

  3. A Method Sustaining the Bioelectric, Biophysical, and Bioenergetic Function of Cultured Rabbit Atrial Cells

    Directory of Open Access Journals (Sweden)

    Noa Kirschner Peretz

    2017-08-01

    Full Text Available Culturing atrial cells leads to a loss in their ability to be externally paced at physiological rates and to maintain their shape. We aim to develop a culture method that sustains the shape of atrial cells along with their biophysical and bioenergetic properties in response to physiological pacing. We hypothesize that adding 2,3-Butanedione 2-monoxime (BDM, which inhibits contraction during the culture period, will preserve these biophysical and bioenergetic properties. Rabbit atrial cells were maintained in culture for 24 h in a medium enriched with a myofilament contraction inhibitor, BDM. The morphology and volume of the cells, including their ability to contract in response to 1–3 Hz electrical pacing, was maintained at the same level as fresh cells. Importantly, the cells could be successfully infected with a GFP adenovirus. Action potentials, Ca2+ transients, and local Ca2+ spark parameters were similar in the cultured and in fresh cells. Finally, these cultured cells' flavoprotein autofluorescence was maintained at a constant level in response to electrical pacing, a response similar to that of fresh cells. Thus, eliminating contraction during the culture period preserves the bioelectric, biophysical and bioenergetic properties of rabbit atrial myocytes. This method therefore has the potential to further improve our understanding of energetic and biochemical regulation in the atria.

  4. Predicting the Presence of Scyphozoan Jellyfish in the Gulf of Mexico Using a Biophysical Model

    Science.gov (United States)

    Aleksa, K. T.; Nero, R. W.; Wiggert, J. D.; Graham, W. M.

    2016-02-01

    The study and quantification of jellyfish (cnidarian medusae and ctenophores) is difficult due to their fragile body plan and a composition similar to their environment. The development of a predictive biophysical jellyfish model would be the first of its kind for the Gulf of Mexico and could provide assistance in ecological research and human interactions. In this study, the collection data of two scyphozoan medusae, Chrysaora quinquecirrha and Aurelia spp., were extracted from SEAMAP trawling surveys and were used to determine biophysical predictors for the presence of large jellyfish medusae in the Gulf of Mexico. Both in situ and remote sensing measurements from 2003 to 2013 were obtained. Logistic regressions were then applied to 27 biophysical parameters derived from these data to explore and determine significant predictors for the presence of medusae. Significant predictors identified by this analysis included water temperature, chlorophyll a, turbidity, distance from shore, and salinity. Future application for this model include foraging assessment of gelatinous predators as well as possible near real time monitoring of the distribution and movement of these medusae in the Gulf of Mexico.

  5. A biophysical approach to the optimisation of dendritic-tumour cell electrofusion

    International Nuclear Information System (INIS)

    Sukhorukov, Vladimir L.; Reuss, Randolph; Endter, Joerg M.; Fehrmann, Steffen; Katsen-Globa, Alisa; Gessner, Petra; Steinbach, Andrea; Mueller, Kilian J.; Karpas, Abraham; Zimmermann, Ulrich; Zimmermann, Heiko

    2006-01-01

    Electrofusion of tumour and dendritic cells (DCs) is a promising approach for production of DC-based anti-tumour vaccines. Although human DCs are well characterised immunologically, little is known about their biophysical properties, including dielectric and osmotic parameters, both of which are essential for the development of efficient electrofusion protocols. In the present study, human DCs from the peripheral blood along with a tumour cell line used as a model fusion partner were examined by means of time-resolved cell volumetry and electrorotation. Based on the biophysical cell data, the electrofusion protocol could be rapidly optimised with respect to the sugar composition of the fusion medium, duration of hypotonic treatment, frequency range for stable cell alignment, and field strengths of breakdown pulses triggering membrane fusion. The hypotonic electrofusion consistently gave a tumour-DC hybrid rate of up to 19%, as determined by counting dually labelled fluorescent hybrids in a microscope. This fusion rate is nearly twice as high as that usually reported in the literature for isotonic media. The experimental findings and biophysical approach presented here are generally useful for the development of efficient electrofusion protocols, especially for rare and valuable human cells

  6. The role of bio-physical cohesive substrates on sediment winnowing and bedform development

    Science.gov (United States)

    Ye, Leiping; Parsons, Daniel; Manning, Andrew

    2017-04-01

    Existing sediment transport and bedform size predictions for natural open-channel flows in many environments are seriously impeded by a lack of process-based knowledge concerning the dynamics of complex bed sediment mixtures comprising cohesionless sand and biologically-active cohesive muds. A series of flume experiments (14 experimental runs) with different substrate mixtures of sand-clay-EPS (Extracellular Polymeric Substance) are combined with a detailed estuarine field survey (Dee estuary, NW England) to investigate the development of bedform morphologies and characteristics of suspended sediment over bio-physical cohesive substrates. The experimental results indicate that winnowing and sediment sorting can occur pervasively in bio-physical cohesive sediment - flow systems. Importantly however, the evolution of the bed and bedform dynamics, and hence turbulence production, is significantly reduced as bed substrate cohesivity increases. The estuarine subtidal zone survey also revealed that the bio-physical cohesion provided by both the clay and microorganism fractions in the bed plays a significant role in controlling the interactions between bed substrate and sediment suspension, deposition and bedform generation. The work will be presented here concludes by outlining the need to extend and revisit the effects of cohesivity in morphodynamic systems and the sets of parameters presently used in numerical modelling, particularly in the context of the impact of climate change on estuarine and coastal systems.

  7. Enhancing Irreversible Electroporation by Manipulating Cellular Biophysics with a Molecular Adjuvant.

    Science.gov (United States)

    Ivey, Jill W; Latouche, Eduardo L; Richards, Megan L; Lesser, Glenn J; Debinski, Waldemar; Davalos, Rafael V; Verbridge, Scott S

    2017-07-25

    Pulsed electric fields applied to cells have been used as an invaluable research tool to enhance delivery of genes or other intracellular cargo, as well as for tumor treatment via electrochemotherapy or tissue ablation. These processes involve the buildup of charge across the cell membrane, with subsequent alteration of transmembrane potential that is a function of cell biophysics and geometry. For traditional electroporation parameters, larger cells experience a greater degree of membrane potential alteration. However, we have recently demonstrated that the nuclear/cytoplasm ratio (NCR), rather than cell size, is a key predictor of response for cells treated with high-frequency irreversible electroporation (IRE). In this study, we leverage a targeted molecular therapy, ephrinA1, known to markedly collapse the cytoplasm of cells expressing the EphA2 receptor, to investigate how biophysical cellular changes resulting from NCR manipulation affect the response to IRE at varying frequencies. We present evidence that the increase in the NCR mitigates the cell death response to conventional electroporation pulsed-electric fields (∼100 μs), consistent with the previously noted size dependence. However, this same molecular treatment enhanced the cell death response to high-frequency electric fields (∼1 μs). This finding demonstrates the importance of considering cellular biophysics and frequency-dependent effects in developing electroporation protocols, and our approach provides, to our knowledge, a novel and direct experimental methodology to quantify the relationship between cell morphology, pulse frequency, and electroporation response. Finally, this novel, to our knowledge, combinatorial approach may provide a paradigm to enhance in vivo tumor ablation through a molecular manipulation of cellular morphology before IRE application. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  8. Plasma membrane--cortical cytoskeleton interactions: a cell biology approach with biophysical considerations.

    Science.gov (United States)

    Kapus, András; Janmey, Paul

    2013-07-01

    From a biophysical standpoint, the interface between the cell membrane and the cytoskeleton is an intriguing site where a "two-dimensional fluid" interacts with an exceedingly complex three-dimensional protein meshwork. The membrane is a key regulator of the cytoskeleton, which not only provides docking sites for cytoskeletal elements through transmembrane proteins, lipid binding-based, and electrostatic interactions, but also serves as the source of the signaling events and molecules that control cytoskeletal organization and remolding. Conversely, the cytoskeleton is a key determinant of the biophysical and biochemical properties of the membrane, including its shape, tension, movement, composition, as well as the mobility, partitioning, and recycling of its constituents. From a cell biological standpoint, the membrane-cytoskeleton interplay underlies--as a central executor and/or regulator--a multitude of complex processes including chemical and mechanical signal transduction, motility/migration, endo-/exo-/phagocytosis, and other forms of membrane traffic, cell-cell, and cell-matrix adhesion. The aim of this article is to provide an overview of the tight structural and functional coupling between the membrane and the cytoskeleton. As biophysical approaches, both theoretical and experimental, proved to be instrumental for our understanding of the membrane/cytoskeleton interplay, this review will "oscillate" between the cell biological phenomena and the corresponding biophysical principles and considerations. After describing the types of connections between the membrane and the cytoskeleton, we will focus on a few key physical parameters and processes (force generation, curvature, tension, and surface charge) and will discuss how these contribute to a variety of fundamental cell biological functions. © 2013 American Physiological Society.

  9. Biophysical Neural Spiking, Bursting, and Excitability Dynamics in Reconfigurable Analog VLSI.

    Science.gov (United States)

    Yu, T; Sejnowski, T J; Cauwenberghs, G

    2011-10-01

    We study a range of neural dynamics under variations in biophysical parameters underlying extended Morris-Lecar and Hodgkin-Huxley models in three gating variables. The extended models are implemented in NeuroDyn, a four neuron, twelve synapse continuous-time analog VLSI programmable neural emulation platform with generalized channel kinetics and biophysical membrane dynamics. The dynamics exhibit a wide range of time scales extending beyond 100 ms neglected in typical silicon models of tonic spiking neurons. Circuit simulations and measurements show transition from tonic spiking to tonic bursting dynamics through variation of a single conductance parameter governing calcium recovery. We similarly demonstrate transition from graded to all-or-none neural excitability in the onset of spiking dynamics through the variation of channel kinetic parameters governing the speed of potassium activation. Other combinations of variations in conductance and channel kinetic parameters give rise to phasic spiking and spike frequency adaptation dynamics. The NeuroDyn chip consumes 1.29 mW and occupies 3 mm × 3 mm in 0.5 μm CMOS, supporting emerging developments in neuromorphic silicon-neuron interfaces.

  10. Cellular Biophysics During Freezing of Rat and Mouse Sperm Predicts Post-thaw Motility1

    Science.gov (United States)

    Hagiwara, Mie; Choi, Jeung Hwan; Devireddy, Ramachandra V.; Roberts, Kenneth P.; Wolkers, Willem F.; Makhlouf, Antoine; Bischof, John C.

    2009-01-01

    Though cryopreservation of mouse sperm yields good survival and motility after thawing, cryopreservation of rat sperm remains a challenge. This study was designed to evaluate the biophysics (membrane permeability) of rat in comparison to mouse to better understand the cooling rate response that contributes to cryopreservation success or failure in these two sperm types. In order to extract subzero membrane hydraulic permeability in the presence of ice, a differential scanning calorimeter (DSC) method was used. By analyzing rat and mouse sperm frozen at 5°C/min and 20°C/min, heat release signatures characteristic of each sperm type were obtained and correlated to cellular dehydration. The dehydration response was then fit to a model of cellular water transport (dehydration) by adjusting cell-specific biophysical (membrane hydraulic permeability) parameters Lpg and ELp. A “combined fit” (to 5°C/min and 20°C/min data) for rat sperm in Biggers-Whitten-Whittingham media yielded Lpg = 0.007 μm min−1 atm−1 and ELp = 17.8 kcal/mol, and in egg yolk cryopreservation media yielded Lpg = 0.005 μm min−1 atm−1 and ELp = 14.3 kcal/mol. These parameters, especially the activation energy, were found to be lower than previously published parameters for mouse sperm. In addition, the biophysical responses in mouse and rat sperm were shown to depend on the constituents of the cryopreservation media, in particular egg yolk and glycerol. Using these parameters, optimal cooling rates for cryopreservation were predicted for each sperm based on a criteria of 5%–15% normalized cell water at −30°C during freezing in cryopreservation media. These predicted rates range from 53°C/min to 70°C/min and from 28°C/min to 36°C/min in rat and mouse, respectively. These predictions were validated by comparison to experimentally determined cryopreservation outcomes, in this case based on motility. Maximum motility was obtained with freezing rates between 50°C/min and 80

  11. Cellular biophysics during freezing of rat and mouse sperm predicts post-thaw motility.

    Science.gov (United States)

    Hagiwara, Mie; Choi, Jeung Hwan; Devireddy, Ramachandra V; Roberts, Kenneth P; Wolkers, Willem F; Makhlouf, Antoine; Bischof, John C

    2009-10-01

    Though cryopreservation of mouse sperm yields good survival and motility after thawing, cryopreservation of rat sperm remains a challenge. This study was designed to evaluate the biophysics (membrane permeability) of rat in comparison to mouse to better understand the cooling rate response that contributes to cryopreservation success or failure in these two sperm types. In order to extract subzero membrane hydraulic permeability in the presence of ice, a differential scanning calorimeter (DSC) method was used. By analyzing rat and mouse sperm frozen at 5 degrees C/min and 20 degrees C/min, heat release signatures characteristic of each sperm type were obtained and correlated to cellular dehydration. The dehydration response was then fit to a model of cellular water transport (dehydration) by adjusting cell-specific biophysical (membrane hydraulic permeability) parameters L(pg) and E(Lp). A "combined fit" (to 5 degrees C/min and 20 degrees C/min data) for rat sperm in Biggers-Whitten-Whittingham media yielded L(pg) = 0.007 microm min(-1) atm(-1) and E(Lp) = 17.8 kcal/mol, and in egg yolk cryopreservation media yielded L(pg) = 0.005 microm min(-1) atm(-1) and E(Lp) = 14.3 kcal/mol. These parameters, especially the activation energy, were found to be lower than previously published parameters for mouse sperm. In addition, the biophysical responses in mouse and rat sperm were shown to depend on the constituents of the cryopreservation media, in particular egg yolk and glycerol. Using these parameters, optimal cooling rates for cryopreservation were predicted for each sperm based on a criteria of 5%-15% normalized cell water at -30 degrees C during freezing in cryopreservation media. These predicted rates range from 53 degrees C/min to 70 degrees C/min and from 28 degrees C/min to 36 degrees C/min in rat and mouse, respectively. These predictions were validated by comparison to experimentally determined cryopreservation outcomes, in this case based on motility. Maximum

  12. Covariance of biophysical data with digital topograpic and land use maps over the FIFE site

    Science.gov (United States)

    Davis, F. W.; Schimel, D. S.; Friedl, M. A.; Michaelsen, J. C.; Kittel, T. G. F.; Dubayah, R.; Dozier, J.

    1992-01-01

    This paper discusses the biophysical stratification of the FIFE site, implementation of the stratification utilizing geographic information system methods, and validation of the stratification with respect to field measurements of biomass, Bowen ratio, soil moisture, and the greenness vegetation index (GVI) derived from TM satellite data. Maps of burning and topographic position were significantly associated with variation in GVI, biomass, and Bowen ratio. The stratified design did not significantly alter the estimated site-wide means for surface climate parameters but accounted for between 25 and 45 percent of the sample variance depending on the variable.

  13. The Colorado Plateau II: biophysical, socioeconomic, and cultural research

    Science.gov (United States)

    Mattson, David J.; van Riper, Charles

    2005-01-01

    The publication of The Colorado Plateau: Cultural, Biological, and Physical Research in 2004 marked a timely summation of current research in the Four Corners states. This new volume, derived from the seventh Biennial Conference on the Colorado Plateau in 2003, complements the previous book by focusing on the integration of science into resource management issues. The 32 chapters range in content from measuring human impacts on cultural resources, through grazing and the wildland-urban interface issues, to parameters of climate change on the Plateau. The book also introduces economic perspectives by considering shifting patterns and regional disparities in the Colorado Plateau economy. A series of chapters on mountain lions explores the human-wildland interface. These chapters deal with the entire spectrum of challenges associated with managing this large mammal species in Arizona and on the Colorado Plateau, conveying a wealth of timely information of interest to wildlife managers and enthusiasts. Another provocative set of chapters on biophysical resources explores the management of forest restoration, from the micro scale all the way up to large-scale GIS analyses of ponderosa pine ecosystems on the Colorado Plateau. Given recent concerns for forest health in the wake of fires, severe drought, and bark-beetle infestation, these chapters will prove enlightening for forest service, park service, and land management professionals at both the federal and state level, as well as general readers interested in how forest management practices will ultimately affect their recreation activities. With broad coverage that touches on topics as diverse as movement patterns of rattlesnakes, calculating watersheds, and rescuing looted rockshelters, this volume stands as a compendium of cutting-edge research on the Colorado Plateau that offers a wealth of insights for many scholars.

  14. The physical basis of biochemistry the foundations of molecular biophysics

    CERN Document Server

    Bergethon, Peter R

    1998-01-01

    The objective of this book is to provide a unifying approach to the study of biophysical chemistry for the advanced undergraduate who has had a year of physics, organic chem­ istry, calculus, and biology. This book began as a revised edition of Biophysical Chemistry: Molecules to Membranes, which Elizabeth Simons and I coauthored. That short volume was written in an attempt to provide a concise text for a one-semester course in biophysical chemistry at the graduate level. The experience of teaching biophysical chemistry to bi­ ologically oriented students over the last decade has made it clear that the subject requires a more fundamental text that unifies the many threads of modem science: physics, chem­ istry, biology, mathematics, and statistics. This book represents that effort. This volume is not a treatment of modem biophysical chemistry with its rich history and many contro­ versies, although a book on that topic is also needed. The Physical Basis of Biochemistry is an introduction to the philosophy...

  15. Crescimento, parâmetros biofísicos e aspectos anatômicos de plantas jovens de seringueira inoculadas com fungo micorrízico arbuscular Glomus clarum Growth, biophysical parameters and anatomical aspects of young rubber tree plants inoculated with arbuscular mycorrhizal fungi Glomus clarum

    Directory of Open Access Journals (Sweden)

    Patrícia Fabian de Araújo Diniz

    2010-03-01

    Full Text Available Fungos micorrízicos são reconhecidamente benéficos quando em associação às plantas por favorecerem seu crescimento e desenvolvimento. Apesar de pouco comum para a seringueira, a inoculação artificial de fungos micorrízicos arbusculares (FMAs tem se mostrado uma alternativa para a redução no uso de fertilizantes e pesticidas nas culturas, bem como para a formação de mudas, visando obtenção de porta-enxertos precoces e bem nutridos. O estudo objetivou avaliar o efeito da inoculação do FMA Glomus clarum no crescimento e características biofísicas e anatômicas de plantas jovens de seringueira. Os tratamentos consistiram de plantas inoculadas com o fungo Glomus clarum adubadas com 50 ppm de fósforo (mic+50P, plantas não inoculadas adubadas com 50 ppm de fósforo (s/mic+50P e plantas não inoculadas adubadas com 500 ppm de fósforo (s/mic+500P. Constatou-se que as plantas micorrizadas apresentaram altura e diâmetro dos caules, matéria seca da parte aérea, densidade estomática e área foliar, semelhantes às plantas s/mic+500P. Maior acúmulo de matéria seca de raiz, maior taxa de transpiração, menor resistência estomática e menor temperatura foliar foram observadas para as plantas micorrizadas. As análises anatômicas das raízes evidenciam a ocorrência de alterações no tecido vascular, com aumento no número de pólos de xilema das raízes das plantas micorrizadas.Mycorrhizal fungi are beneficial when associated with plants because they favor growth and develop. Although infrequent, artificial inoculation of arbuscular mycorrhizal fungi (AMF has become an alternative to reduce the use of fertilizers and pesticides in crops, as well as for the formation of seedlings, to obtain precocious and well fed rootstocks. The objective of the study was to evaluate the effect of inoculation of AMF Glomus clarum on growth and biophysical and anatomical characteristics of young rubber trees. The treatments consist of plants

  16. 2. biophysical work meeting. Papers; 2. Biophysikalische Arbeitstagung; Vortraege

    Energy Technology Data Exchange (ETDEWEB)

    1992-11-01

    The report comprises 18 papers held at the 2nd Biophysical Work Meeting, 11 - 13 September 1991 in Schlema, Germany. The history of biophysics in Germany particularly of radiation biophysics and radon research, measurements of the radiation effects of radon and the derivation of limits, radon balneotherapy and consequences of uranium ore mining are dealt with. (orig.) [Deutsch] Der Report enthaelt 18 Vortraege, die auf der 2. Biophysikalischen Arbeitstagung in Schlema vom 11. bis 13. September 1991 gehalten wurden. Es werden die Geschichte der Biophysik in Deutschland, speziell der Strahlenbiophysik und Radonforschung, Messungen von Radon und seinen Folgeprodukten, Epidemiologie und Strahlenbiologie zur Bestimmung der Strahlenwirkung des Radons und die Ableitung entsprechender Grenzwerte, Radon-Balneotherapie und Folgen des Uranerzbergbaus behandelt. (orig.)

  17. Role of Membrane Biophysics in Alzheimer's - related cell pathways

    Directory of Open Access Journals (Sweden)

    Donghui eZhu

    2015-05-01

    Full Text Available Cellular membrane alterations are commonly observed in many diseases, including Alzheimer’s disease (AD. Membrane biophysical properties, such as membrane molecular order, membrane fluidity, organization of lipid rafts, and adhesion between membrane and cytoskeleton, play an important role in various cellular activities and functions. While membrane biophysics impacts a broad range of cellular pathways, this review addresses the role of membrane biophysics in amyloid-β peptide aggregation, Aβ-induced oxidative pathways, amyloid precursor protein processing, and cerebral endothelial functions in AD. Understanding the mechanism(s underlying the effects of cell membrane properties on cellular processes should shed light on the development of new preventive and therapeutic strategies for this devastating disease.

  18. Large-scale biophysical evaluation of protein PEGylation effects

    DEFF Research Database (Denmark)

    Vernet, Erik; Popa, Gina; Pozdnyakova, Irina

    2016-01-01

    PEGylation is the most widely used method to chemically modify protein biopharmaceuticals, but surprisingly limited public data is available on the biophysical effects of protein PEGylation. Here we report the first large-scale study, with site-specific mono-PEGylation of 15 different proteins...... of PEGylation on the thermal stability of a protein based on data generated by circular dichroism (CD), differential scanning calorimetry (DSC), or differential scanning fluorimetry (DSF). In addition, DSF was validated as a fast and inexpensive screening method for thermal unfolding studies of PEGylated...... proteins. Multivariate data analysis revealed clear trends in biophysical properties upon PEGylation for a subset of proteins, although no universal trends were found. Taken together, these findings are important in the consideration of biophysical methods and evaluation of second...

  19. Preface: Special Topic on Single-Molecule Biophysics.

    Science.gov (United States)

    Makarov, Dmitrii E; Schuler, Benjamin

    2018-03-28

    Single-molecule measurements are now almost routinely used to study biological systems and processes. The scope of this special topic emphasizes the physics side of single-molecule observations, with the goal of highlighting new developments in physical techniques as well as conceptual insights that single-molecule measurements bring to biophysics. This issue also comprises recent advances in theoretical physical models of single-molecule phenomena, interpretation of single-molecule signals, and fundamental areas of statistical mechanics that are related to single-molecule observations. A particular goal is to illustrate the increasing synergy between theory, simulation, and experiment in single-molecule biophysics.

  20. Institute of Biochemistry and Biophysics. Research Report 1996-1997

    International Nuclear Information System (INIS)

    1998-01-01

    Scientific interests of the Institute of Biochemistry and Biophysics of the Polish Academy of Sciences have evolved from classical biochemistry, biophysics and physiological chemistry to up-to-date molecular biology. Research interests are focussed on replication, mutagenesis and repair of DNA; regulation of gene expression at various levels; biosynthesis and post-translational modifications of proteins; gene sequencing and functional analysis of open reading frames; structure, function and regulation of enzymes; conformation of proteins and peptides; modelling of structures and prediction of functions of proteins; mechanisms of electron transfer in polypeptides

  1. [Biophysical methods in assessment of the skin microcirculation system].

    Science.gov (United States)

    Dynnik, O B; Mostovoĭ, S E; Berezovskiĭ, V A

    2008-01-01

    In this work has been analyzed the potential of biophysics methods in estimations of the microcirculatory system. Capillaroresistometry, Computer capillaroscopy and Laser Doppler Flowmetry can to detect of the endothelial dysfunction in the patients with chronic hepatic diseases. This instrumentals biophysics methods may be used in clinical investigations for screening early pathological conditions with dysfunction of the microcirculatory system. The methods Laser Doppler Flowmetry is important for investigations the patients with others diseases and for dynamical monitoring by quality of the treatment. The purpose of these methods an objective estimation of disorders in the microcirculatory system.

  2. Cell biology, biophysics, and mechanobiology: From the basics to Clinics.

    Science.gov (United States)

    Zeng, Y

    2017-04-29

    Cell biology, biomechanics and biophysics are the key subjects that guide our understanding in diverse areas of tissue growth, development, remodeling and homeostasis. Novel discoveries such as molecular mechanism, and mechanobiological mechanism in cell biology, biomechanics and biophysics play essential roles in our understanding of the pathogenesis of various human diseases, as well as in designing the treatment of these diseases. In addition, studies in these areas will also facilitate early diagnostics of human diseases, such as cardiovascular diseases and cancer. In this special issue, we collected 10 original research articles and 1 review...

  3. Institute of Biochemistry and Biophysics. Research Report 1996-1997

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    Scientific interests of the Institute of Biochemistry and Biophysics of the Polish Academy of Sciences have evolved from classical biochemistry, biophysics and physiological chemistry to up-to-date molecular biology. Research interests are focussed on replication, mutagenesis and repair of DNA; regulation of gene expression at various levels; biosynthesis and post-translational modifications of proteins; gene sequencing and functional analysis of open reading frames; structure, function and regulation of enzymes; conformation of proteins and peptides; modelling of structures and prediction of functions of proteins; mechanisms of electron transfer in polypeptides.

  4. Statistical and biophysical aspects of survival curve

    International Nuclear Information System (INIS)

    Kellerer, A.M.

    1980-01-01

    Statistic fluctuation in a series of consequently taken survival curves of asynchronous cells of a hamster of the V79 line during X-ray irradiation, are considered. In each of the experiments fluctuations are close to those expected on the basis of the Poisson distribution. The fluctuation of cell sensitivity in different experiments of one series can reach 10%. The normalization of each experiment in mean values permits to obtain the ''idealized'' survival curve. The survival logarithm in this curve is proportional to the absorbed dose and its square only at low radiation doses. Such proportionality in V lab 79 cells in the late S-phase is observed at all doses. Using the microdosimetric approach, the distance where the interaction of radiolysis products or subinjury takes place to make the dependence of injury on the dose non-linear, is determined. In the case of interaction distances of 10-100 nm, the linear component is shown to become comparable in value with the linear injury component at doses of the order of several hundred rad only in the case, when the interaction distance is close to micrometre [ru

  5. Closing remarks

    International Nuclear Information System (INIS)

    Reig, J.

    2007-01-01

    Good afternoon. Before providing the closing remarks on behalf of the NEA, I would like to take this opportunity and make some personal reflections, if you allow me Mr. Chairman. I have had the opportunity to take part in the three workshops on public communication organised by the NEA. In the first one in Paris in 2000, representing my country, Spain, and in the two last ones in Ottawa in 2004 and Tokyo today, on behalf of the NEA. The topics for the three workshops follow a logical order, first the focus was on investing in trust in a time when public communication was becoming a big challenge for the regulators. Second, maintaining and measuring public confidence to assess how credible regulators are in front of the public; and finally here in Tokyo, transparency, which is a basic element to achieve trust and credibility. In my view, a regulatory decision has three main components, it has to be technically sound. legally correct and well communicated. The emphasis in the early years was in the technical matters, till legal issues became a key element to achieve the political acceptance from governments and local authorities. Finally the public communication aspects resulted into a major effort and challenge to achieve social acceptance. (author)

  6. Biophysical constraints on leaf expansion in a tall conifer.

    Science.gov (United States)

    Fredrick C. Meinzer; Barbara J. Bond; Jennifer A. Karanian

    2008-01-01

    The physiological mechanisms responsible for reduced extension growth as trees increase in height remain elusive. We evaluated biophysical constraints on leaf expansion in old-growth Douglas-fir (Psuedotsuga menziesii (Mirb.) Franco) trees. Needle elongation rates, plastic and elastic extensibility, bulk leaf water, (L...

  7. Seminal Fluid Analysis And Biophysical Profile: Findings And ...

    African Journals Online (AJOL)

    Seminal Fluid Analysis And Biophysical Profile: Findings And Relevance In Infertile Males In Ilorin, Nigeria. EK Oghagbon, AAG Jimoh, SA Adebisi. Abstract. To determine if there was a bearing of body mass index (BMI) on male infertility, a cross-sectional study of males of infertile couples, attending our infertility clinic was ...

  8. Delineating Biophysical Environments of the Sunda Banda Seascape, Indonesia

    Directory of Open Access Journals (Sweden)

    Mingshu Wang

    2015-01-01

    Full Text Available The Sunda Banda Seascape (SBS, located in the center of the Coral Triangle, is a global center of marine biodiversity and a conservation priority. We proposed the first biophysical environmental delineation of the SBS using globally available satellite remote sensing and model-assimilated data to categorize this area into unique and meaningful biophysical classes. Specifically, the SBS was partitioned into eight biophysical classes characterized by similar sea surface temperature, chlorophyll a concentration, currents, and salinity patterns. Areas within each class were expected to have similar habitat types and ecosystem functions. Our work supplemented prevailing global marine management schemes by focusing in on a regional scale with finer spatial resolution. It also provided a baseline for academic research, ecological assessments and will facilitate marine spatial planning and conservation activities in the area. In addition, the framework and methods of delineating biophysical environments we presented can be expanded throughout the whole Coral Triangle to support research and conservation activities in this important region.

  9. Perspectives and Plans for Graduate Studies. 16. Biophysics 1974.

    Science.gov (United States)

    Ontario Council on Graduate Studies, Toronto. Advisory Committee on Academic Planning.

    In March, 1973, after a review of the Ontario universities' three-year plans, a provisional embargo was placed on doctoral work in biophysics. A full-scale assessment with outside consultants was not necessary in the case of a provisional embargo. Instead, the method used to remove the embargo was self-study by the discipline group leading to a…

  10. Southwest Ecological Restoration Institutes (SWERI) Biophysical Monitoring Workshop Report

    Science.gov (United States)

    Joseph Seidenberg; Judy Springer; Tessa Nicolet; Mike Battaglia; Christina Vothja

    2009-01-01

    On October 15-16, 2009, the Southwest Ecological Restoration Institutes (SWERI) hosted a workshop in which the participants would 1) build a common understanding of the types of monitoring that are occurring in forested ecosystems of the Southwest; 2) analyze and agree on an efficient, yet robust set of biophysical variables that can be used by land mangers and...

  11. Polish Academy of Sciences Institute of Biochemistry and Biophysics research report 1994-1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    Scientific interests of Institute of Biochemistry and Biophysics Polish Academy of Sciences are focused on DNA replication and repair, gene expression, gene sequencing and molecular biophysics. The work reviews research projects of the Institute in 1994-1995.

  12. Polish Academy of Sciences Institute of Biochemistry and Biophysics research report 1994-1995

    International Nuclear Information System (INIS)

    1996-01-01

    Scientific interests of Institute of Biochemistry and Biophysics Polish Academy of Sciences are focused on DNA replication and repair, gene expression, gene sequencing and molecular biophysics. The work reviews research projects of the Institute in 1994-1995

  13. Polish Academy of Sciences Institute of Biochemistry and Biophysics research report 1994-1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    Scientific interests of Institute of Biochemistry and Biophysics Polish Academy of Sciences are focused on DNA replication and repair, gene expression, gene sequencing and molecular biophysics. The work reviews research projects of the Institute in 1994-1995.

  14. Surface-enhanced Raman scattering: a new optical probe in molecular biophysics and biomedicine

    DEFF Research Database (Denmark)

    Kneipp, J.; Wittig, B.; Bohr, Henrik

    2010-01-01

    Sensitive and detailed molecular structural information plays an increasing role in molecular biophysics and molecular medicine. Therefore, vibrational spectroscopic techniques, such as Raman scattering, which provide high structural information content are of growing interest in biophysical and ...

  15. Calculation of the ceramics Weibull parameters

    Czech Academy of Sciences Publication Activity Database

    Fuis, Vladimír; Návrat, Tomáš

    2011-01-01

    Roč. 58, - (2011), s. 642-647 ISSN 2010-376X. [International Conference on Bioinformatics and Biomedicine 2011. Bali, 26.10.2011-28.10.2011] Institutional research plan: CEZ:AV0Z20760514 Keywords : biomaterial parameters * Weibull statistics * ceramics Subject RIV: BO - Biophysics http://www.waset.org/journals/waset/v58/v58-132.pdf

  16. Predicting Variation of DNA Shape Preferences in Protein-DNA Interaction in Cancer Cells with a New Biophysical Model.

    Science.gov (United States)

    Batmanov, Kirill; Wang, Junbai

    2017-09-18

    DNA shape readout is an important mechanism of transcription factor target site recognition, in addition to the sequence readout. Several machine learning-based models of transcription factor-DNA interactions, considering DNA shape features, have been developed in recent years. Here, we present a new biophysical model of protein-DNA interactions by integrating the DNA shape properties. It is based on the neighbor dinucleotide dependency model BayesPI2, where new parameters are restricted to a subspace spanned by the dinucleotide form of DNA shape features. This allows a biophysical interpretation of the new parameters as a position-dependent preference towards specific DNA shape features. Using the new model, we explore the variation of DNA shape preferences in several transcription factors across various cancer cell lines and cellular conditions. The results reveal that there are DNA shape variations at FOXA1 (Forkhead Box Protein A1) binding sites in steroid-treated MCF7 cells. The new biophysical model is useful for elucidating the finer details of transcription factor-DNA interaction, as well as for predicting cancer mutation effects in the future.

  17. What is life? Bio-physical perspectives.

    Science.gov (United States)

    Gladyshev, G P

    2009-01-01

    Life arises and develops in gravitationally bound atomic systems, under certain conditions, in the presence of the inflow of energy. A condition of structural dynamic reactivity to the energy inflow qualifies what are anthropomorphically considered as "alive objects". Alive objects, in this perspective, include such rudimentary animate atomic structures as the retinal molecule C20H28o to the herpes simplex virus C102H152N26o29 to the human being, a twenty-six element atomic structure, which can be quantified further as thermodynamic quasi-closed supramolecular systems, which are part of natural open systems. These systems appear and evolve in periodic conditions near to internal equilibrium. This systems attribute of dynamic life can be understood further by the determination and use of mathematical "state functions", which are functions that quantify the state of a system defined by the ensemble of physical quantities: temperature, pressure, composition, etc., which characterize the system, but neither by its surroundings nor by its history. In this view, the phenomenon of a life is easily understood as a general consequence of the laws of the universe, in particular, the laws of thermodynamics, which in the geocentric perspective translate to a formulation of "hierarchical thermodynamics" and a "principle of substance stability". The formation of living thermodynamic structures, in short, arises on the nanolevel by a constantly varying environment that causes variety of living forms. The definition of a life as the bio-chemical-physical phenomenon can thus be given on the basis of the exact sciences, i. e. chemistry, physics, and thermodynamics, without mention of numerous private attributes of a living substance and without physically baseless models of mathematical modeling, such as Prigoginean thermodynamics.

  18. An allosteric gating model recapitulates the biophysical properties of IK,L expressed in mouse vestibular type I hair cells.

    Science.gov (United States)

    Spaiardi, Paolo; Tavazzani, Elisa; Manca, Marco; Milesi, Veronica; Russo, Giancarlo; Prigioni, Ivo; Marcotti, Walter; Magistretti, Jacopo; Masetto, Sergio

    2017-11-01

    showed complex activation and deactivation kinetics, which we faithfully reproduced by an allosteric channel gating scheme where the channel is able to open from all (five) closed states. The 'early' open states substantially contribute to I K,L activation at negative voltages. This study provides the first complete description of the 'native' biophysical properties of I K,L in adult mouse vestibular type I hair cells. © 2017 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

  19. Simulation of Tillage Systems Impact on Soil Biophysical Properties Using the SALUS Model

    Directory of Open Access Journals (Sweden)

    Luigi Sartori

    2011-02-01

    Full Text Available A sustainable land management has been defined as the management system that allows for production, while minimizing risk, maintaining quality of soil and water. Tillage systems can significantly decrease soil carbon storage and influence the soil environment of a crop. Crop growth models can be useful tools in evaluating the impact of different tillage systems on soil biophysical properties and on the growth and final yield of the crops. The objectives of this paper were i to illustrate the SALUS model and its tillage component; ii to evaluate the effects of different tillage systems on water infiltration and time to ponding, iii to simulate the effect of tillage systems on some soil biophysical properties. The SALUS (System Approach to Land Use Sustainability model is designed to simulate continuous crop, soil, water and nutrient conditions under different tillage and crop residues management strategies for multiple years. Predictions of changes in surface residue, bulk density, runoff, drainage and evaporation were consistent with expected behaviours of these parameters as described in the literature. The experiment to estimate the time to ponding curve under different tillage system confirmed the theory and showed the beneficial effects of the residue on soil surface with respect to water infiltration. It also showed that the no-tillage system is a more appropriate system to adopt in areas characterized by high intensity rainfall.

  20. Simulation of Tillage Systems Impact on Soil Biophysical Properties Using the SALUS Model

    Directory of Open Access Journals (Sweden)

    Bruno Basso

    2006-12-01

    Full Text Available A sustainable land management has been defined as the management system that allows for production, while minimizing risk, maintaining quality of soil and water. Tillage systems can significantly decrease soil carbon storage and influence the soil environment of a crop. Crop growth models can be useful tools in evaluating the impact of different tillage systems on soil biophysical properties and on the growth and final yield of the crops. The objectives of this paper were i to illustrate the SALUS model and its tillage component; ii to evaluate the effects of different tillage systems on water infiltration and time to ponding, iii to simulate the effect of tillage systems on some soil biophysical properties. The SALUS (System Approach to Land Use Sustainability model is designed to simulate continuous crop, soil, water and nutrient conditions under different tillage and crop residues management strategies for multiple years. Predictions of changes in surface residue, bulk density, runoff, drainage and evaporation were consistent with expected behaviours of these parameters as described in the literature. The experiment to estimate the time to ponding curve under different tillage system confirmed the theory and showed the beneficial effects of the residue on soil surface with respect to water infiltration. It also showed that the no-tillage system is a more appropriate system to adopt in areas characterized by high intensity rainfall.

  1. Biophysical characterisation of calumenin as a charged F508del-CFTR folding modulator.

    Directory of Open Access Journals (Sweden)

    Rashmi Tripathi

    Full Text Available The cystic fibrosis transmembrane regulator (CFTR is a cyclic-AMP dependent chloride channel expressed at the apical surface of epithelial cells lining various organs such as the respiratory tract. Defective processing and functioning of this protein caused by mutations in the CFTR gene results in loss of ionic balance, defective mucus clearance, increased proliferation of biofilms and inflammation of human airways observed in cystic fibrosis (CF patients. The process by which CFTR folds and matures under the influence of various chaperones in the secretory pathway remains incompletely understood. Recently, calumenin, a secretory protein, belonging to the CREC family of low affinity calcium binding proteins has been identified as a putative CFTR chaperone whose biophysical properties and functions remain uncharacterized. We compared hydropathy, instability, charge, unfoldability, disorder and aggregation propensity of calumenin and other CREC family members with CFTR associated chaperones and calcium binding proteins, wild-type and mutant CFTR proteins and intrinsically disordered proteins (IDPs. We observed that calumenin, along with other CREC proteins, was significantly more charged and less folded compared to CFTR associated chaperones. Moreover like IDPs, calumenin and other CREC proteins were found to be less hydrophobic and aggregation prone. Phylogenetic analysis revealed a close link between calumenin and other CREC proteins indicating how evolution might have shaped their similar biophysical properties. Experimentally, calumenin was observed to significantly reduce F508del-CFTR aggregation in a manner similar to AavLEA1, a well-characterized IDP. Fluorescence microscopy based imaging analysis also revealed altered trafficking of calumenin in bronchial cells expressing F508del-CFTR, indicating its direct role in the pathophysiology of CF. In conclusion, calumenin is characterized as a charged protein exhibiting close similarity with

  2. Chief, Structural Biophysics Laboratory | Center for Cancer Research

    Science.gov (United States)

    The SBL Chief is expected to establish a strong research program in structural biology/biophysics in addition to providing leadership of the SBL and the structural biology community in the NCI Intramural Program.  Applicants should hold a Ph.D., M.D./Ph.D., or equivalent doctoral degree in a relevant discipline, and should possess outstanding communication skills and documented leadership experience.  Tenured faculty or industrial scientists of equivalent rank with a demonstrated commitment to structural biophysics should apply.  Salary will be commensurate with experience and accomplishments.  This position is not restricted to U.S. citizens. A full civil service package of benefits (including health insurance, life insurance, and retirement) is available. This position is subject to a background investigation.  The NIH is dedicated to building a diverse community in its training and employment programs.

  3. Synthetic Biology: Engineering Living Systems from Biophysical Principles.

    Science.gov (United States)

    Bartley, Bryan A; Kim, Kyung; Medley, J Kyle; Sauro, Herbert M

    2017-03-28

    Synthetic biology was founded as a biophysical discipline that sought explanations for the origins of life from chemical and physical first principles. Modern synthetic biology has been reinvented as an engineering discipline to design new organisms as well as to better understand fundamental biological mechanisms. However, success is still largely limited to the laboratory and transformative applications of synthetic biology are still in their infancy. Here, we review six principles of living systems and how they compare and contrast with engineered systems. We cite specific examples from the synthetic biology literature that illustrate these principles and speculate on their implications for further study. To fully realize the promise of synthetic biology, we must be aware of life's unique properties. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  4. From hadron therapy to cosmic rays: a life in biophysics

    CERN Multimedia

    Christine Sutton

    2014-01-01

    In 1954 – the year CERN was founded – another scientific journey began at what is now the Lawrence Berkeley National Laboratory. Beams of protons from a particle accelerator were used for the first time by John Lawrence – a doctor and the brother of Ernest Lawrence, the physicist after whom the Berkeley lab is named – to treat patients with cancer. For many years, Eleanor Blakely has been one of the leaders of that journey. She visited CERN last week and spoke with the Bulletin about her life in biophysics.   Use of the cylcotron beam to mimic "shooting stars" seen by astronauts. Black hood on subject Cornelius Tobias keeps out light during neutron irradiation experiment at the 184-inch accelerator. Helping to position Tobias in the beam line are (left to right) John Lyman of Biomedical Division, and Ralph Thomas of Health Physics. (Photo courtesy of Lawrence Berkeley National Laboratory.) Interested in biophysics, which was still a new...

  5. Achievements and challenges in structural bioinformatics and computational biophysics.

    Science.gov (United States)

    Samish, Ilan; Bourne, Philip E; Najmanovich, Rafael J

    2015-01-01

    The field of structural bioinformatics and computational biophysics has undergone a revolution in the last 10 years. Developments that are captured annually through the 3DSIG meeting, upon which this article reflects. An increase in the accessible data, computational resources and methodology has resulted in an increase in the size and resolution of studied systems and the complexity of the questions amenable to research. Concomitantly, the parameterization and efficiency of the methods have markedly improved along with their cross-validation with other computational and experimental results. The field exhibits an ever-increasing integration with biochemistry, biophysics and other disciplines. In this article, we discuss recent achievements along with current challenges within the field. © The Author 2014. Published by Oxford University Press.

  6. Evolution and Biophysics of the Escherichia coli lac Operon

    Science.gov (United States)

    Ray, J. Christian; Igoshin, Oleg; Quan, Selwyn; Monds, Russell; Cooper, Tim; Balázsi, Gábor

    2011-03-01

    To understand, predict, and control the evolution of living organisms, we consider biophysical effects and molecular network architectures. The lactose utilization system of E. coli is among the most well-studied molecular networks in biology, making it an ideal candidate for such studies. Simulations show how the genetic architecture of the wild-type operon attenuates large metabolic intermediate fluctuations that are predicted to occur in an equivalent system with the component genes on separate operons. Quantification of gene expression in the lac operon evolved in growth conditions containing constant lactose, alternating with glucose, or constant glucose, shows characteristic gene expression patterns depending on conditions. We are simulating these conditions to show context-dependent biophysical sources and costs of different lac operon architectures.

  7. Biophysical dosimetry using electron paramagnetic resonance in human tooth

    International Nuclear Information System (INIS)

    Khan, R.F.H.; Boreham, D.R.; Rink, W.J.

    2002-01-01

    Accidental dosimetry utilizing radiation induced paramagnetic species in biophysical tissues like teeth is a technique; that can measure the amount of radiation exposure to an individual. The major problem in implementing this technique at low doses is the presence of native organic signal, and various other artifacts produced as a result of sample processing. After a series of experimental trials, we developed an optimum set of rules, which uses high temperature ultrasonic treatment of enamel in KOH, multiple sample rotation during in-cavity measurement of natural and calibrated added irradiations, and dose construction using a backward extrapolation method. By using this we report the successful dose reconstruction in a few of our laboratory samples in 100 mGy range (76.29 ± 30.14) mGy with reasonably low uncertainty. Keywords: biophysical dosimetry, human tooth enamel, low dose measurements, accidental dosimetry (author)

  8. Biophysical approach to low back pain: a pilot report.

    Science.gov (United States)

    Foletti, Alberto; Pokorný, Jiry

    2015-01-01

    Since biophysical treatment has been reported to be effective in the general management of pain, we decided to assess the specific effect and treatment duration of this therapeutic strategy in low back pain. We were interested in verifying the possibility that a single clinical procedure could reduce pain and improve patients' quality of life within a period of three months. An Electromagnetic Information Transfer Through Aqueous System was employed to record endogenous therapeutic signals from each individual using an electromagnetic recording device (Med Select 729). A highly significant reduction in the Roland Morris low back pain and disability questionnaire score was observed after 3 months following a single biophysical intervention (11.83 ± 6 at baseline versus 2.3 ± 3.25 at 3 months, p < 0.0001). This preliminary report provides further evidence of the theoretical implications and clinical applications of Quantum Electro Dynamic concepts in biology and medicine.

  9. The biophysics of renal sympathetic denervation using radiofrequency energy.

    Science.gov (United States)

    Patel, Hitesh C; Dhillon, Paramdeep S; Mahfoud, Felix; Lindsay, Alistair C; Hayward, Carl; Ernst, Sabine; Lyon, Alexander R; Rosen, Stuart D; di Mario, Carlo

    2014-05-01

    Renal sympathetic denervation is currently performed in the treatment of resistant hypertension by interventionists who otherwise do not typically use radiofrequency (RF) energy ablation in their clinical practice. Adequate RF lesion formation is dependent upon good electrode-tissue contact, power delivery, electrode-tissue interface temperature, target-tissue impedance and the size of the catheter's active electrode. There is significant interplay between these variables and hence an appreciation of the biophysical determinants of RF lesion formation is required to provide effective and safe clinical care to our patients. In this review article, we summarize the biophysics of RF ablation and explain why and how complications of renal sympathetic denervation may occur and discuss methods to minimise them.

  10. Biophysical Evaluation of Food Decontamination Effects on Tissue and Bacteria

    DEFF Research Database (Denmark)

    Andersen, Ann Zahle; Duelund, Lars; Brewer, Jonathan

    2011-01-01

    Traditionally, the effects and efficiency of food surface decontamination processes, such as chlorine washing, radiation, or heating, have been evaluated by sensoric analysis and colony-forming unit (CFU) counts of surface swabs or carcass rinses. These methods suffice when determining probable...... consumer responses or meeting legislative contamination limits. However, in the often very costly, optimization process of a new method, more quantitative and unbiased results are invaluable. In this study, we employed a biophysical approach for the investigation of qualitative and quantitative changes...... that there are no contradictions between data obtained by either approach. However, the biophysical methods draw a much more nuanced picture of the effects and efficiency of the investigated decontamination method, revealing, e.g., an exponential dose/response relationship between SonoSteam® treatment time and changes in collagen...

  11. Mass spectrometry for the biophysical characterization of therapeutic monoclonal antibodies.

    Science.gov (United States)

    Zhang, Hao; Cui, Weidong; Gross, Michael L

    2014-01-21

    Monoclonal antibodies (mAbs) are powerful therapeutics, and their characterization has drawn considerable attention and urgency. Unlike small-molecule drugs (150-600 Da) that have rigid structures, mAbs (∼150 kDa) are engineered proteins that undergo complicated folding and can exist in a number of low-energy structures, posing a challenge for traditional methods in structural biology. Mass spectrometry (MS)-based biophysical characterization approaches can provide structural information, bringing high sensitivity, fast turnaround, and small sample consumption. This review outlines various MS-based strategies for protein biophysical characterization and then reviews how these strategies provide structural information of mAbs at the protein level (intact or top-down approaches), peptide, and residue level (bottom-up approaches), affording information on higher order structure, aggregation, and the nature of antibody complexes. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  12. Biophysical and electrochemical studies of protein-nucleic acid interactions

    Czech Academy of Sciences Publication Activity Database

    Bowater, R. P.; Cobb, A:M.; Pivoňková, Hana; Havran, Luděk; Fojta, Miroslav

    2015-01-01

    Roč. 146, č. 5 (2015), s. 723-739 ISSN 0026-9247 R&D Projects: GA ČR(CZ) GBP206/12/G151; GA ČR(CZ) GAP301/11/2076 Institutional support: RVO:68081707 Keywords : ISOTHERMAL TITRATION CALORIMETRY * OSMIUM-TETROXIDE COMPLEXES * SURFACE-PLASMON RESONANCE Subject RIV: BO - Biophysics Impact factor: 1.131, year: 2015

  13. Raman spectroscopy reveals biophysical markers in skin cancer surgical margins

    Science.gov (United States)

    Feng, Xu; Moy, Austin J.; Nguyen, Hieu T. M.; Zhang, Yao; Fox, Matthew C.; Sebastian, Katherine R.; Reichenberg, Jason S.; Markey, Mia K.; Tunnell, James W.

    2018-02-01

    The recurrence rate of nonmelanoma skin cancer is highly related to the residual tumor after surgery. Although tissueconserving surgery, such as Mohs surgery, is a standard method for the treatment of nonmelanoma skin cancer, they are limited by lengthy and costly frozen-section histopathology. Raman spectroscopy (RS) is proving to be an objective, sensitive, and non-destructive tool for detecting skin cancer. Previous studies demonstrated the high sensitivity of RS in detecting tumor margins of basal cell carcinoma (BCC). However, those studies rely on statistical classification models and do not elucidate the skin biophysical composition. As a result, we aim to discover the biophysical differences between BCC and primary normal skin structures (including epidermis, dermis, hair follicle, sebaceous gland and fat). We obtained freshly resected ex vivo skin samples from fresh resection specimens from 14 patients undergoing Mohs surgery. Raman images were acquired from regions containing one or more structures using a custom built 830nm confocal Raman microscope. The spectra were grouped using K-means clustering analysis and annotated as either BCC or each of the five normal structures by comparing with the histopathology image of the serial section. The spectral data were then fit by a previously established biophysical model with eight primary skin constituents. Our results show that BCC has significant differences in the fit coefficients of nucleus, collagen, triolein, keratin and elastin compared with normal structures. Our study reveals RS has the potential to detect biophysical changes in resection margins, and supports the development of diagnostic algorithms for future intraoperative implementation of RS during Mohs surgery.

  14. Electrophysiological Data and the Biophysical Modelling of Local Cortical Circuits

    Directory of Open Access Journals (Sweden)

    Dimitris Pinotsis

    2014-03-01

    Full Text Available This paper shows how recordings of gamma oscillations – under different experimental conditions or from different subjects – can be combined with a class of population models called neural fields and dynamic causal modeling (DCM to distinguish among alternative hypotheses regarding cortical structure and function. This approach exploits inter-subject variability and trial-specific effects associated with modulations in the peak frequency of gamma oscillations. It draws on the computational power of Bayesian model inversion, when applied to neural field models of cortical dynamics. Bayesian model comparison allows one to adjudicate among different mechanistic hypotheses about cortical excitability, synaptic kinetics and the cardinal topographic features of local cortical circuits. It also provides optimal parameter estimates that quantify neuromodulation and the spatial dispersion of axonal connections or summation of receptive fields in the visual cortex. This paper provides an overview of a family of neural field models that have been recently implemented using the DCM toolbox of the academic freeware Statistical Parametric Mapping (SPM. The SPM software is a popular platform for analyzing neuroimaging data, used by several neuroscience communities worldwide. DCM allows for a formal (Bayesian statistical analysis of cortical network connectivity, based upon realistic biophysical models of brain responses. It is this particular feature of DCM – the unique combination of generative models with optimization techniques based upon (variational Bayesian principles – that furnishes a novel way to characterize functional brain architectures. In particular, it provides answers to questions about how the brain is wired and how it responds to different experimental manipulations. For a review of the general role of neural fields in SPM the reader can consult e.g. see [1]. Neural fields have a long and illustrious history in mathematical

  15. A quantitative overview of biophysical forces impinging on neural function

    International Nuclear Information System (INIS)

    Mueller, Jerel K; Tyler, William J

    2014-01-01

    The fundamentals of neuronal membrane excitability are globally described using the Hodgkin-Huxley (HH) model. The HH model, however, does not account for a number of biophysical phenomena associated with action potentials or propagating nerve impulses. Physical mechanisms underlying these processes, such as reversible heat transfer and axonal swelling, have been compartmentalized and separately investigated to reveal neuronal activity is not solely influenced by electrical or biochemical factors. Instead, mechanical forces and thermodynamics also govern neuronal excitability and signaling. To advance our understanding of neuronal function and dysfunction, compartmentalized analyses of electrical, chemical, and mechanical processes need to be revaluated and integrated into more comprehensive theories. The present perspective is intended to provide a broad overview of biophysical forces that can influence neural function, but which have been traditionally underappreciated in neuroscience. Further, several examples where mechanical forces have been shown to exert their actions on nervous system development, signaling, and plasticity are highlighted to underscore their importance in sculpting neural function. By considering the collective actions of biophysical forces influencing neuronal activity, our working models can be expanded and new paradigms can be applied to the investigation and characterization of brain function and dysfunction. (topical review)

  16. Temporal measurement and analysis of high-resolution spectral signatures of plants and relationships to biophysical characteristics

    Science.gov (United States)

    Bostater, Charles R., Jr.; Rebbman, Jan; Hall, Carlton; Provancha, Mark; Vieglais, David

    1995-11-01

    Measurements of temporal reflectance signatures as a function of growing season for sand live oak (Quercus geminata), myrtle oak (Q. myrtifolia, and saw palmetto (Serenoa repens) were collected during a two year study period. Canopy level spectral reflectance signatures, as a function of 252 channels between 368 and 1115 nm, were collected using near nadir viewing geometry and a consistent sun illumination angle. Leaf level reflectance measurements were made in the laboratory using a halogen light source and an environmental optics chamber with a barium sulfate reflectance coating. Spectral measurements were related to several biophysical measurements utilizing optimal passive ambient correlation spectroscopy (OPACS) technique. Biophysical parameters included percent moisture, water potential (MPa), total chlorophyll, and total Kjeldahl nitrogen. Quantitative data processing techniques were used to determine optimal bands based on the utilization of a second order derivative or inflection estimator. An optical cleanup procedure was then employed that computes the double inflection ratio (DIR) spectra for all possible three band combinations normalized to the previously computed optimal bands. These results demonstrate a unique approach to the analysis of high spectral resolution reflectance signatures for estimation of several biophysical measures of plants at the leaf and canopy level from optimally selected bands or bandwidths.

  17. Biophysical influence of coumarin 35 on bovine serum albumin: Spectroscopic study

    Science.gov (United States)

    Bayraktutan, Tuğba; Onganer, Yavuz

    2017-01-01

    The binding mechanism and protein-fluorescence probe interactions between bovine serum albumin (BSA) and coumarin 35 (C35) was investigated by using UV-Vis absorption and fluorescence spectroscopies since they remain major research topics in biophysics. The spectroscopic data indicated that a fluorescence quenching process for BSA-C35 system was occurred. The fluorescence quenching processes were analyzed using Stern-Volmer method. In this regard, Stern-Volmer quenching constants (KSV) and binding constants were calculated at different temperatures. The distance r between BSA (donor) and C35 (acceptor) was determined by exploiting fluorescence resonance energy transfer (FRET) method. Synchronous fluorescence spectra were also studied to observe information about conformational changes. Moreover, thermodynamics parameters were calculated for better understanding of interactions and conformational changes of the system.

  18. Surface Biophysical Parameters Derived From Remote Sensing Data For Urban Changes Assessment

    International Nuclear Information System (INIS)

    Zoran, M.; Pavelescu, G.; Nicolae, D.N.; Talianu, C.

    2007-01-01

    Remote sensing is a key application in global-change science, being very useful for urban climatology and land use-Landcover dynamics analysis.Multi-spectral and multi-temporal satellite imagery (LANDSAT TM, ETM ;SAR ) over 1984 - 2004 period for Bucharest urban area provide the most reliable technique of monitoring of different urban structures regarding the net radiation and heat fluxes associated with urbanization at the regional scale. This study attempts to provide environmental awareness to urban planners in future urban development. The land cover information, properly classified, can provide a spatially and temporally explicit view of societal and environmental attributes and can be an important complement to in-situ measurements

  19. Establishment of a biophysical model to optimize endoscopic targeting of magnetic nanoparticles for cancer treatment.

    Science.gov (United States)

    Roeth, Anjali A; Slabu, Ioana; Baumann, Martin; Alizai, Patrick H; Schmeding, Maximilian; Guentherodt, Gernot; Schmitz-Rode, Thomas; Neumann, Ulf P

    2017-01-01

    Superparamagnetic iron oxide nanoparticles (SPION) may be used for local tumor treatment by coupling them to a drug and accumulating them locally with magnetic field traps, that is, a combination of permanent magnets and coils. Thereafter, an alternating magnetic field generates heat which may be used to release the thermosensitively bound drug and for hyperthermia. Until today, only superficial tumors can be treated with this method. Our aim was to transfer this method into an endoscopic setting to also reach the majority of tumors located inside the body. To find the ideal endoscopic magnetic field trap, which accumulates the most SPION, we first developed a biophysical model considering anatomical as well as physical conditions. Entities of choice were esophageal and prostate cancer. The magnetic susceptibilities of different porcine and rat tissues were measured with a superconducting quantum interference device. All tissues showed diamagnetic behavior. The evaluation of clinical data (computed tomography scan, endosonography, surgical reports, pathological evaluation) of patients gave insight into the topographical relationship between the tumor and its surroundings. Both were used to establish the biophysical model of the tumors and their surroundings, closely mirroring the clinical situation, in which we could virtually design, place and evaluate different electromagnetic coil configurations to find optimized magnetic field traps for each tumor entity. By simulation, we could show that the efficiency of the magnetic field traps can be enhanced by 38-fold for prostate and 8-fold for esophageal cancer. Therefore, our approach of endoscopic targeting is an improvement of the magnetic drug-targeting setups for SPION tumor therapy as it holds the possibility of reaching tumors inside the body in a minimal-invasive way. Future animal experiments must prove these findings in vivo.

  20. Biophysical approach to chronic kidney disease management in older patients

    Directory of Open Access Journals (Sweden)

    Alberto Foletti

    2016-06-01

    Full Text Available Chronic kidney disease (CKD and its clinical progression are a critical issue in an aging population. Therefore, strategies aimed at preventing and managing the decline of renal function are warranted. Recent evidence has provided encouraging results for the improvement of renal function achieved through an integrated biophysical approach, but prospective studies on the clinical efficacy of this strategy are still lacking. This was an open-label prospective pilot study to investigate the effect of electromagnetic information transfer through the aqueous system on kidney function of older patients affected by stage 1 or 2 CKD. Patients received biophysical therapy every 3 months over a 1-year period. Estimated glomerular filtration rate (eGFR values were calculated using the CKD–Epidemiology Collaboration formula, and were recorded at baseline and at the end of treatment. Overall, 58 patients (mean age 74.8 ± 3.7 years were included in the study. At baseline, mean eGFR was 64.6 ± 15.5 mL/min, and it significantly increased to 69.9 ± 15.8 mL/min after 1 year (+5.2 ± 10 mL/min, p<0.0002. The same trend was observed among men (+5.7 ± 10.2 mL/min, p<0.0064 and women (+4.7 ± 9.9 mL/min, p<0.014. When results were analyzed by sex, no difference was found between the 2 groups. Although further and larger prospective studies are needed, our findings suggest that an integrated biophysical approach may be feasible in the management of older patients with early-stage CKD, to reduce and prevent the decline of renal function due to aging or comorbidities.

  1. Surface enhanced raman spectroscopy analytical, biophysical and life science applications

    CERN Document Server

    Schlücker, Sebastian

    2013-01-01

    Covering everything from the basic theoretical and practical knowledge to new exciting developments in the field with a focus on analytical and life science applications, this monograph shows how to apply surface-enhanced Raman scattering (SERS) for solving real world problems. From the contents: * Theory and practice of SERS * Analytical applications * SERS combined with other analytical techniques * Biophysical applications * Life science applications including various microscopies Aimed at analytical, surface and medicinal chemists, spectroscopists, biophysicists and materials scientists. Includes a Foreword by the renowned Raman spectroscopist Professor Wolfgang Kiefer, the former Editor-in-Chief of the Journal of Raman Spectroscopy.

  2. Short-Term Memory and Its Biophysical Model

    Science.gov (United States)

    Wang, Wei; Zhang, Kai; Tang, Xiao-wei

    1996-12-01

    The capacity of short-term memory has been studied using an integrate-and-fire neuronal network model. It is found that the storage of events depend on the manner of the correlation between the events, and the capacity is dominated by the value of after-depolarization potential. There is a monotonic increasing relationship between the value of after-depolarization potential and the memory numbers. The biophysics relevance of the network model is discussed and different kinds of the information processes are studied too.

  3. Hydrophobic ampersand hydrophilic: Theoretical models of solvation for molecular biophysics

    International Nuclear Information System (INIS)

    Pratt, L.R.; Tawa, G.J.; Hummer, G.; Garcia, A.E.; Corcelli, S.A.

    1996-01-01

    Molecular statistical thermodynamic models of hydration for chemistry and biophysics have advanced abruptly in recent years. With liquid water as solvent, salvation phenomena are classified as either hydrophobic or hydrophilic effects. Recent progress in treatment of hydrophilic effects have been motivated by continuum dielectric models interpreted as a modelistic implementation of second order perturbation theory. New results testing that perturbation theory of hydrophilic effects are presented and discussed. Recent progress in treatment of hydrophobic effects has been achieved by applying information theory to discover models of packing effects in dense liquids. The simplest models to which those ideas lead are presented and discussed

  4. Remote sensing of the Canadian Arctic: Modelling biophysical variables

    Science.gov (United States)

    Liu, Nanfeng

    It is anticipated that Arctic vegetation will respond in a variety of ways to altered temperature and precipitation patterns expected with climate change, including changes in phenology, productivity, biomass, cover and net ecosystem exchange. Remote sensing provides data and data processing methodologies for monitoring and assessing Arctic vegetation over large areas. The goal of this research was to explore the potential of hyperspectral and high spatial resolution multispectral remote sensing data for modelling two important Arctic biophysical variables: Percent Vegetation Cover (PVC) and the fraction of Absorbed Photosynthetically Active Radiation (fAPAR). A series of field experiments were conducted to collect PVC and fAPAR at three Canadian Arctic sites: (1) Sabine Peninsula, Melville Island, NU; (2) Cape Bounty Arctic Watershed Observatory (CBAWO), Melville Island, NU; and (3) Apex River Watershed (ARW), Baffin Island, NU. Linear relationships between biophysical variables and Vegetation Indices (VIs) were examined at different spatial scales using field spectra (for the Sabine Peninsula site) and high spatial resolution satellite data (for the CBAWO and ARW sites). At the Sabine Peninsula site, hyperspectral VIs exhibited a better performance for modelling PVC than multispectral VIs due to their capacity for sampling fine spectral features. The optimal hyperspectral bands were located at important spectral features observed in Arctic vegetation spectra, including leaf pigment absorption in the red wavelengths and at the red-edge, leaf water absorption in the near infrared, and leaf cellulose and lignin absorption in the shortwave infrared. At the CBAWO and ARW sites, field PVC and fAPAR exhibited strong correlations (R2 > 0.70) with the NDVI (Normalized Difference Vegetation Index) derived from high-resolution WorldView-2 data. Similarly, high spatial resolution satellite-derived fAPAR was correlated to MODIS fAPAR (R2 = 0.68), with a systematic

  5. Mass spectrometry in structural biology and biophysics architecture, dynamics, and interaction of biomolecules

    CERN Document Server

    Kaltashov, Igor A; Desiderio, Dominic M; Nibbering, Nico M

    2012-01-01

    The definitive guide to mass spectrometry techniques in biology and biophysics The use of mass spectrometry (MS) to study the architecture and dynamics of proteins is increasingly common within the biophysical community, and Mass Spectrometry in Structural Biology and Biophysics: Architecture, Dynamics, and Interaction of Biomolecules, Second Edition provides readers with detailed, systematic coverage of the current state of the art. Offering an unrivalled overview of modern MS-based armamentarium that can be used to solve the most challenging problems in biophysics, structural biol

  6. Biophysical Properties of Cultivated Pastures in the Brazilian Savanna Biome: An Analysis in the Spatial-Temporal Domains Based on Ground and Satellite Data

    Directory of Open Access Journals (Sweden)

    Fernando M. Araújo

    2013-01-01

    Full Text Available Brazil has the largest commercial beef cattle herd in the world, with cattle ranching being particularly prominent in the 200-million ha, Brazilian neotropical moist savanna biome, known as Cerrado, one of the world’s hotspots for biodiversity conservation. As decreasing productivity is a major concern affecting the Cerrado pasturelands, evaluation of pasture conditions through the determination of biophysical parameters is instrumental for more effective management practices and herd occupation strategies. Within this context, the primary goal of this study was the regional assessment of pasture biophysical properties, through the scaling of wet- and dry-season ground truth data (total biomass, green biomass, and % green cover via the combined use of high (Landsat-TM and moderate (MODIS spatial resolution vegetation index images. Based on the high correlation found between NDVI (normalized difference vegetation index and % green cover (r = 0.95, monthly MODIS-based % green cover images were derived for the 2009–2010 hydrological cycle, which were able to capture major regional patterns and differences in pasture biophysical responses, including the increasing greenness values towards the southern portions of the biome, due to both local conditions (e.g., more fertile soils and management practices. These results corroborate the development of biophysically-based landscape degradation indices, in support of improved land use governance and natural area conservation in the Cerrado.

  7. Indoor Fast Neutron Generator for Biophysical and Electronic Applications

    Science.gov (United States)

    Cannuli, A.; Caccamo, M. T.; Marchese, N.; Tomarchio, E. A.; Pace, C.; Magazù, S.

    2018-05-01

    This study focuses the attention on an indoor fast neutron generator for biophysical and electronic applications. More specifically, the findings obtained by several simulations with the MCNP Monte Carlo code, necessary for the realization of a shield for indoor measurements, are presented. Furthermore, an evaluation of the neutron spectrum modification caused by the shielding is reported. Fast neutron generators are a valid and interesting available source of neutrons, increasingly employed in a wide range of research fields, such as science and engineering. The employed portable pulsed neutron source is a MP320 Thermo Scientific neutron generator, able to generate 2.5 MeV neutrons with a neutron yield of 2.0 x 106 n/s, a pulse rate of 250 Hz to 20 KHz and a duty factor varying from 5% to 100%. The neutron generator, based on Deuterium-Deuterium nuclear fusion reactions, is employed in conjunction with a solid-state photon detector, made of n-type high-purity germanium (PINS-GMX by ORTEC) and it is mainly addressed to biophysical and electronic studies. The present study showed a proposal for the realization of a shield necessary for indoor applications for MP320 neutron generator, with a particular analysis of the transport of neutrons simulated with Monte Carlo code and described the two main lines of research in which the source will be used.

  8. Biophysical influence of airborne carbon nanomaterials on natural pulmonary surfactant.

    Science.gov (United States)

    Valle, Russell P; Wu, Tony; Zuo, Yi Y

    2015-05-26

    Inhalation of nanoparticles (NP), including lightweight airborne carbonaceous nanomaterials (CNM), poses a direct and systemic health threat to those who handle them. Inhaled NP penetrate deep pulmonary structures in which they first interact with the pulmonary surfactant (PS) lining at the alveolar air-water interface. In spite of many research efforts, there is a gap of knowledge between in vitro biophysical study and in vivo inhalation toxicology since all existing biophysical models handle NP-PS interactions in the liquid phase. This technical limitation, inherent in current in vitro methodologies, makes it impossible to simulate how airborne NP deposit at the PS film and interact with it. Existing in vitro NP-PS studies using liquid-suspended particles have been shown to artificially inflate the no-observed adverse effect level of NP exposure when compared to in vivo inhalation studies and international occupational exposure limits (OELs). Here, we developed an in vitro methodology called the constrained drop surfactometer (CDS) to quantitatively study PS inhibition by airborne CNM. We show that airborne multiwalled carbon nanotubes and graphene nanoplatelets induce a concentration-dependent PS inhibition under physiologically relevant conditions. The CNM aerosol concentrations controlled in the CDS are comparable to those defined in international OELs. Development of the CDS has the potential to advance our understanding of how submicron airborne nanomaterials affect the PS lining of the lung.

  9. Mechanoresponsive stem cells to target cancer metastases through biophysical cues.

    Science.gov (United States)

    Liu, Linan; Zhang, Shirley X; Liao, Wenbin; Farhoodi, Henry P; Wong, Chi W; Chen, Claire C; Ségaliny, Aude I; Chacko, Jenu V; Nguyen, Lily P; Lu, Mengrou; Polovin, George; Pone, Egest J; Downing, Timothy L; Lawson, Devon A; Digman, Michelle A; Zhao, Weian

    2017-07-26

    Despite decades of effort, little progress has been made to improve the treatment of cancer metastases. To leverage the central role of the mechanoenvironment in cancer metastasis, we present a mechanoresponsive cell system (MRCS) to selectively identify and treat cancer metastases by targeting the specific biophysical cues in the tumor niche in vivo. Our MRCS uses mechanosensitive promoter-driven mesenchymal stem cell (MSC)-based vectors, which selectively home to and target cancer metastases in response to specific mechanical cues to deliver therapeutics to effectively kill cancer cells, as demonstrated in a metastatic breast cancer mouse model. Our data suggest a strong correlation between collagen cross-linking and increased tissue stiffness at the metastatic sites, where our MRCS is specifically activated by the specific cancer-associated mechano-cues. MRCS has markedly reduced deleterious effects compared to MSCs constitutively expressing therapeutics. MRCS indicates that biophysical cues, specifically matrix stiffness, are appealing targets for cancer treatment due to their long persistence in the body (measured in years), making them refractory to the development of resistance to treatment. Our MRCS can serve as a platform for future diagnostics and therapies targeting aberrant tissue stiffness in conditions such as cancer and fibrotic diseases, and it should help to elucidate mechanobiology and reveal what cells "feel" in the microenvironment in vivo. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  10. Biophysical basis for the geometry of conical stromatolites.

    Science.gov (United States)

    Petroff, Alexander P; Sim, Min Sub; Maslov, Andrey; Krupenin, Mikhail; Rothman, Daniel H; Bosak, Tanja

    2010-06-01

    Stromatolites may be Earth's oldest macroscopic fossils; however, it remains controversial what, if any, biological processes are recorded in their morphology. Although the biological interpretation of many stromatolite morphologies is confounded by the influence of sedimentation, conical stromatolites form in the absence of sedimentation and are, therefore, considered to be the most robust records of biophysical processes. A qualitative similarity between conical stromatolites and some modern microbial mats suggests a photosynthetic origin for ancient stromatolites. To better understand and interpret ancient fossils, we seek a quantitative relationship between the geometry of conical stromatolites and the biophysical processes that control their growth. We note that all modern conical stromatolites and many that formed in the last 2.8 billion years display a characteristic centimeter-scale spacing between neighboring structures. To understand this prominent-but hitherto uninterpreted-organization, we consider the role of diffusion in mediating competition between stromatolites. Having confirmed this model through laboratory experiments and field observation, we find that organization of a field of stromatolites is set by a diffusive time scale over which individual structures compete for nutrients, thus linking form to physiology. The centimeter-scale spacing between modern and ancient stromatolites corresponds to a rhythmically fluctuating metabolism with a period of approximately 20 hr. The correspondence between the observed spacing and the day length provides quantitative support for the photosynthetic origin of conical stromatolites throughout geologic time.

  11. Developing a physics expert identity in a biophysics research group

    Science.gov (United States)

    Rodriguez, Idaykis; Goertzen, Renee Michelle; Brewe, Eric; Kramer, Laird H.

    2015-06-01

    We investigate the development of expert identities through the use of the sociocultural perspective of learning as participating in a community of practice. An ethnographic case study of biophysics graduate students focuses on the experiences the students have in their research group meetings. The analysis illustrates how the communities of practice-based identity constructs of competencies characterize student expert membership. A microanalysis of speech, sound, tones, and gestures in video data characterize students' social competencies in the physics community of practice. Results provide evidence that students at different stages of their individual projects have opportunities to develop social competencies such as mutual engagement, negotiability of the repertoire, and accountability to the enterprises as they interact with group members. The biophysics research group purposefully designed a learning trajectory including conducting research and writing it for publication in the larger community of practice as a pathway to expertise. The students of the research group learn to become socially competent as specific experts of their project topic and methodology, ensuring acceptance, agency, and membership in their community of practice. This work expands research on physics expertise beyond the cognitive realm and has implications for how to design graduate learning experiences to promote expert identity development.

  12. Biophysics of filament length regulation by molecular motors

    International Nuclear Information System (INIS)

    Kuan, Hui-Shun; Betterton, M D

    2013-01-01

    Regulating physical size is an essential problem that biological organisms must solve from the subcellular to the organismal scales, but it is not well understood what physical principles and mechanisms organisms use to sense and regulate their size. Any biophysical size-regulation scheme operates in a noisy environment and must be robust to other cellular dynamics and fluctuations. This work develops theory of filament length regulation inspired by recent experiments on kinesin-8 motor proteins, which move with directional bias on microtubule filaments and alter microtubule dynamics. Purified kinesin-8 motors can depolymerize chemically-stabilized microtubules. In the length-dependent depolymerization model, the rate of depolymerization tends to increase with filament length, because long filaments accumulate more motors at their tips and therefore shorten more quickly. When balanced with a constant filament growth rate, this mechanism can lead to a fixed polymer length. However, the mechanism by which kinesin-8 motors affect the length of dynamic microtubules in cells is less clear. We study the more biologically realistic problem of microtubule dynamic instability modulated by a motor-dependent increase in the filament catastrophe frequency. This leads to a significant decrease in the mean filament length and a narrowing of the filament length distribution. The results improve our understanding of the biophysics of length regulation in cells. (paper)

  13. Climate Change Effects on Agriculture: Economic Responses to Biophysical Shocks

    Science.gov (United States)

    Nelson, Gerald C.; Valin, Hugo; Sands, Ronald D.; Havlik, Petr; Ahammad, Helal; Deryng, Delphine; Elliott, Joshua; Fujimori, Shinichiro; Hasegawa, Tomoko; Heyhoe, Edwina

    2014-01-01

    Agricultural production is sensitive to weather and thus directly affected by climate change. Plausible estimates of these climate change impacts require combined use of climate, crop, and economic models. Results from previous studies vary substantially due to differences in models, scenarios, and data. This paper is part of a collective effort to systematically integrate these three types of models. We focus on the economic component of the assessment, investigating how nine global economic models of agriculture represent endogenous responses to seven standardized climate change scenarios produced by two climate and five crop models. These responses include adjustments in yields, area, consumption, and international trade. We apply biophysical shocks derived from the Intergovernmental Panel on Climate Change's representative concentration pathway with end-of-century radiative forcing of 8.5 W/m(sup 2). The mean biophysical yield effect with no incremental CO2 fertilization is a 17% reduction globally by 2050 relative to a scenario with unchanging climate. Endogenous economic responses reduce yield loss to 11%, increase area of major crops by 11%, and reduce consumption by 3%. Agricultural production, cropland area, trade, and prices show the greatest degree of variability in response to climate change, and consumption the lowest. The sources of these differences include model structure and specification; in particular, model assumptions about ease of land use conversion, intensification, and trade. This study identifies where models disagree on the relative responses to climate shocks and highlights research activities needed to improve the representation of agricultural adaptation responses to climate change.

  14. Social and Biophysical Predictors of Public Perceptions of Extreme Fires

    Science.gov (United States)

    Hall, T. E.; Kooistra, C. M.; Paveglio, T.; Gress, S.; Smith, A. M.

    2013-12-01

    To date, what constitutes an 'extreme' fire has been approached separately by biophysical and social scientists. Research on the biophysical characteristics of fires has identified potential dimensions of extremity, including fire size and vegetation mortality. On the social side, factors such as the degree of immediate impact to one's life and property or the extent of social disruption in the community contribute to a perception of extremity. However, some biophysical characteristics may also contribute to perceptions of extremity, including number of simultaneous ignitions, rapidity of fire spread, atypical fire behavior, and intensity of smoke. Perceptions of these impacts can vary within and across communities, but no studies to date have investigated such perceptions in a comprehensive way. In this study, we address the question, to what extent is the magnitude of impact of fires on WUI residents' well-being explained by measurable biophysical characteristics of the fire and subjective evaluations of the personal and community-level impacts of the fire? We bring together diverse strands of psychological theory, including landscape perception, mental models, risk perception, and community studies. The majority of social science research on fires has been in the form of qualitative case studies, and our study is methodologically unique by using a nested design (hierarchical modeling) to enable generalizable conclusions across a wide range of fires and human communities. We identified fires that burned in 2011 or 2012 in the northern Rocky Mountain region that were at least 1,000 acres and that intersected (within 15 km) urban clusters or identified Census places. For fires where an adequately large number of households was located in proximity to the fire, we drew random samples of approximately 150 individuals for each fire. We used a hybrid internet (Qualtrics) and mail survey, following the Dillman method, to measure individual perceptions. We developed two

  15. Integrating socio-economic and biophysical data to enhance watershed management and planning

    Science.gov (United States)

    Pirani, Farshad Jalili; Mousavi, Seyed Alireza

    2016-09-01

    Sustainability has always been considered as one of the main aspects of watershed management plans. In many developing countries, watershed management practices and planning are usually performed by integrating biophysical layers, and other existing layers which cannot be identified as geographic layers are ignored. We introduce an approach to consider some socioeconomic parameters which are important for watershed management decisions. Ganj basin in Chaharmahal-Bakhtiari Province was selected as the case study area, which includes three traditional sanctums: Ganj, Shiremard and Gerdabe Olya. Socioeconomic data including net agricultural income, net ranching income, population and household number, literacy rate, unemployment rate, population growth rate and active population were mapped within traditional sanctums and then were integrated into other biophysical layers. After overlaying and processing these data to determine management units, different quantitative and qualitative approaches were adopted to achieve a practical framework for watershed management planning and relevant plans for homogeneous units were afterwards proposed. Comparing the results with current plans, the area of allocated lands to different proposed operations considering both qualitative and quantitative approaches were the same in many cases and there was a meaningful difference with current plans; e.g., 3820 ha of lands are currently managed under an enclosure plan, while qualitative and quantitative approaches in this study suggest 1388 and 1428 ha to be allocated to this operation type, respectively. Findings show that despite the ambiguities and complexities, different techniques could be adopted to incorporate socioeconomic conditions in watershed management plans. This introductory approach will help to enhance watershed management decisions with more attention to societal background and economic conditions, which will presumably motivate local communities to participate in

  16. Improving evapotranspiration in a land surface model using biophysical variables derived from MSG/SEVIRI satellite

    Directory of Open Access Journals (Sweden)

    N. Ghilain

    2012-08-01

    Full Text Available Monitoring evapotranspiration over land is highly dependent on the surface state and vegetation dynamics. Data from spaceborn platforms are desirable to complement estimations from land surface models. The success of daily evapotranspiration monitoring at continental scale relies on the availability, quality and continuity of such data. The biophysical variables derived from SEVIRI on board the geostationary satellite Meteosat Second Generation (MSG and distributed by the Satellite Application Facility on Land surface Analysis (LSA-SAF are particularly interesting for such applications, as they aimed at providing continuous and consistent daily time series in near-real time over Africa, Europe and South America. In this paper, we compare them to monthly vegetation parameters from a database commonly used in numerical weather predictions (ECOCLIMAP-I, showing the benefits of the new daily products in detecting the spatial and temporal (seasonal and inter-annual variability of the vegetation, especially relevant over Africa. We propose a method to handle Leaf Area Index (LAI and Fractional Vegetation Cover (FVC products for evapotranspiration monitoring with a land surface model at 3–5 km spatial resolution. The method is conceived to be applicable for near-real time processes at continental scale and relies on the use of a land cover map. We assess the impact of using LSA-SAF biophysical variables compared to ECOCLIMAP-I on evapotranspiration estimated by the land surface model H-TESSEL. Comparison with in-situ observations in Europe and Africa shows an improved estimation of the evapotranspiration, especially in semi-arid climates. Finally, the impact on the land surface modelled evapotranspiration is compared over a north–south transect with a large gradient of vegetation and climate in Western Africa using LSA-SAF radiation forcing derived from remote sensing. Differences are highlighted. An evaluation against remote sensing derived land

  17. Combining biophysical methods for the analysis of protein complex stoichiometry and affinity in SEDPHAT

    International Nuclear Information System (INIS)

    Zhao, Huaying; Schuck, Peter

    2015-01-01

    Global multi-method analysis for protein interactions (GMMA) can increase the precision and complexity of binding studies for the determination of the stoichiometry, affinity and cooperativity of multi-site interactions. The principles and recent developments of biophysical solution methods implemented for GMMA in the software SEDPHAT are reviewed, their complementarity in GMMA is described and a new GMMA simulation tool set in SEDPHAT is presented. Reversible macromolecular interactions are ubiquitous in signal transduction pathways, often forming dynamic multi-protein complexes with three or more components. Multivalent binding and cooperativity in these complexes are often key motifs of their biological mechanisms. Traditional solution biophysical techniques for characterizing the binding and cooperativity are very limited in the number of states that can be resolved. A global multi-method analysis (GMMA) approach has recently been introduced that can leverage the strengths and the different observables of different techniques to improve the accuracy of the resulting binding parameters and to facilitate the study of multi-component systems and multi-site interactions. Here, GMMA is described in the software SEDPHAT for the analysis of data from isothermal titration calorimetry, surface plasmon resonance or other biosensing, analytical ultracentrifugation, fluorescence anisotropy and various other spectroscopic and thermodynamic techniques. The basic principles of these techniques are reviewed and recent advances in view of their particular strengths in the context of GMMA are described. Furthermore, a new feature in SEDPHAT is introduced for the simulation of multi-method data. In combination with specific statistical tools for GMMA in SEDPHAT, simulations can be a valuable step in the experimental design

  18. Micro-morphologic changes around biophysically-stimulated titanium implants in ovariectomized rats

    Directory of Open Access Journals (Sweden)

    Chang Ting-Ling

    2007-07-01

    Full Text Available Abstract Background Osteoporosis may present a risk factor in achievement of osseointegration because of its impact on bone remodeling properties of skeletal phsiology. The purpose of this study was to evaluate micro-morphological changes in bone around titanium implants exposed to mechanical and electrical-energy in osteoporotic rats. Methods Fifteen 12-week old sprague-dowley rats were ovariectomized to develop osteoporosis. After 8 weeks of healing period, two titanium implants were bilaterally placed in the proximal metaphyses of tibia. The animals were randomly divided into a control group and biophysically-stimulated two test groups with five animals in each group. In the first test group, a pulsed electromagnetic field (PEMF stimulation was administrated at a 0.2 mT 4 h/day, whereas the second group received low-magnitude high-frequency mechanical vibration (MECHVIB at 50 Hz 14 min/day. Following completion of two week treatment period, all animals were sacrificed. Bone sites including implants were sectioned, removed en bloc and analyzed using a microCT unit. Relative bone volume and bone micro-structural parameters were evaluated for 144 μm wide peri-implant volume of interest (VOI. Results Mean relative bone volume in the peri-implant VOI around implants PEMF and MECHVIB was significantly higher than of those in control (P P > .05 while the difference in trabecular-number among test and control groups was significant in all VOIs (P Conclusion Biophysical stimulation remarkably enhances bone volume around titanium implants placed in osteoporotic rats. Low-magnitude high-frequency MECHVIB is more effective than PEMF on bone healing in terms of relative bone volume.

  19. A synthesized biophysical and social vulnerability assessment for Taiwan

    Science.gov (United States)

    Lee, Yung-Jaan

    2017-11-01

    Taiwan, located in the Western Pacific, is a country that is one of the most vulnerable to disasters that are associated with the changing climate; it is located within the Ring of Fire, which is the most geologically active region in the world. The environmental and geological conditions in Taiwan are sensitive and vulnerable to such disasters. Owing to increasing urbanization in Taiwan, floods and climate-related disasters have taken an increasing toll on human lives. As global warming accelerates the rising of sea levels and increasing of the frequency of extreme weather events, disasters will continue to affect socioeconomic development and human conditions. Under such circumstances, researchers and policymakers alike must recognize the importance of providing useful knowledge concerning vulnerability, disaster recovery and resilience. Strategies for reducing vulnerability and climate-related disaster risks and for increasing resilience involve preparedness, mitigation and adaptation. In the last two decades, extreme climate events have caused severe flash floods, debris flows, landslides, and other disasters and have had negative effects of many sectors, including agriculture, infrastructure and health. Since climate change is expected to have a continued impact on socio-economic development, this work develops a vulnerability assessment framework that integrates both biophysical and social vulnerability and supports synthesized vulnerability analyses to identify vulnerable areas in Taiwan. Owing to its geographical, geological and climatic features, Taiwan is susceptible to earthquakes, typhoons, droughts and various induced disasters. Therefore, Taiwan has the urgent task of establishing a framework for assessing vulnerability as a planning and policy tool that can be used to identify not only the regions that require special attention but also hotspots in which efforts should be made to reduce vulnerability and the risk of climate-related disaster. To

  20. Irrigation Requirement Estimation Using Vegetation Indices and Inverse Biophysical Modeling

    Science.gov (United States)

    Bounoua, Lahouari; Imhoff, Marc L.; Franks, Shannon

    2010-01-01

    We explore an inverse biophysical modeling process forced by satellite and climatological data to quantify irrigation requirements in semi-arid agricultural areas. We constrain the carbon and water cycles modeled under both equilibrium, balance between vegetation and climate, and non-equilibrium, water added through irrigation. We postulate that the degree to which irrigated dry lands vary from equilibrium climate conditions is related to the amount of irrigation. The amount of water required over and above precipitation is considered as an irrigation requirement. For July, results show that spray irrigation resulted in an additional amount of water of 1.3 mm per occurrence with a frequency of 24.6 hours. In contrast, the drip irrigation required only 0.6 mm every 45.6 hours or 46% of that simulated by the spray irrigation. The modeled estimates account for 87% of the total reported irrigation water use, when soil salinity is not important and 66% in saline lands.

  1. The case for biophysics super-groups in physics departments.

    Science.gov (United States)

    Hoogenboom, Bart W; Leake, Mark

    2018-06-04

    Increasing numbers of physicists engage in research activities that address biological questions from physics perspectives or strive to develop physics insights from active biological processes. The on-going development and success of such activities morph our ways of thinking about what it is to 'do biophysics' and add to our understanding of the physics of life. Many scientists in this research and teaching landscape are homed in physics departments. A challenge for a hosting department is how to group, name and structure such biophysicists to best add value to their emerging research and teaching but also to the portfolio of the whole department. Here we discuss these issues and speculate on strategies. Creative Commons Attribution license.

  2. Fragility of complexity biophysical systems by neutron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Magazu, Salvatore [Dipartimento di Fisica, Universita di Messina, P.O. Box 55, I-98166 Messina (Italy)]. E-mail: smagazu@unime.it; Migliardo, Federica [Dipartimento di Fisica, Universita di Messina, P.O. Box 55, I-98166 Messina (Italy); Bellocco, Ersilia [Dipartimento di Chimica Organica e Biologica, Universita di Messina, I-98166 Messina (Italy); Lagana, Giuseppina [Dipartimento di Chimica Organica e Biologica, Universita di Messina, I-98166 Messina (Italy); Mondelli, Claudia [CNR-INFM OGG and CRS-SOFT, c/o ILL, 6 Jules Horowitz, BP 156, 38042 Grenoble Cedex 9 (France)

    2006-11-15

    Neutron scattering is an exceptional tool to investigate structural and dynamical properties of systems of biophysical interest, such as proteins, enzymes, lipids and sugars. Moreover, elastic neutron scattering enhances the investigation of atomic motions in hydrated proteins in a wide temperature range and on the picosecond timescale. Homologous disaccharides, such as trehalose, maltose and sucrose, are cryptobiotic substances, since they allow to many organisms to undergo in a 'suspended life' state, known as cryptobiosis in extreme environmental conditions. The present paper is aimed to discuss the fragility degree of disaccharides, as evaluated of the temperature dependence of the mean square displacement by elastic neutron scattering, in order to link this feature with their bioprotective functions.

  3. The physics, biophysics and technology of photodynamic therapy

    International Nuclear Information System (INIS)

    Wilson, Brian C; Patterson, Michael S

    2008-01-01

    Photodynamic therapy (PDT) uses light-activated drugs to treat diseases ranging from cancer to age-related macular degeneration and antibiotic-resistant infections. This paper reviews the current status of PDT with an emphasis on the contributions of physics, biophysics and technology, and the challenges remaining in the optimization and adoption of this treatment modality. A theme of the review is the complexity of PDT dosimetry due to the dynamic nature of the three essential components-light, photosensitizer and oxygen. Considerable progress has been made in understanding the problem and in developing instruments to measure all three, so that optimization of individual PDT treatments is becoming a feasible target. The final section of the review introduces some new frontiers of research including low dose rate (metronomic) PDT, two-photon PDT, activatable PDT molecular beacons and nanoparticle-based PDT. (topical review)

  4. Biophysical information in asymmetric and symmetric diurnal bidirectional canopy reflectance

    Science.gov (United States)

    Vanderbilt, Vern C.; Caldwell, William F.; Pettigrew, Rita E.; Ustin, Susan L.; Martens, Scott N.; Rousseau, Robert A.; Berger, Kevin M.; Ganapol, B. D.; Kasischke, Eric S.; Clark, Jenny A.

    1991-01-01

    The authors present a theory for partitioning the information content in diurnal bidirectional reflectance measurements in order to detect differences potentially related to biophysical variables. The theory, which divides the canopy reflectance into asymmetric and symmetric functions of solar azimuth angle, attributes asymmetric variation to diurnal changes in the canopy biphysical properties. The symmetric function is attributed to the effects of sunlight interacting with a hypothetical average canopy which would display the average diurnal properties of the actual canopy. The authors analyzed radiometer data collected diurnally in the Thematic Mapper wavelength bands from two walnut canopies that received differing irrigation treatments. The reflectance of the canopies varied with sun and view angles and across seven bands in the visible, near-infrared, and middle infrared wavelength regions. Although one of the canopies was permanently water stressed and the other was stressed in mid-afternoon each day, no water stress signature was unambiguously evident in the reflectance data.

  5. The physics, biophysics and technology of photodynamic therapy.

    Science.gov (United States)

    Wilson, Brian C; Patterson, Michael S

    2008-05-07

    Photodynamic therapy (PDT) uses light-activated drugs to treat diseases ranging from cancer to age-related macular degeneration and antibiotic-resistant infections. This paper reviews the current status of PDT with an emphasis on the contributions of physics, biophysics and technology, and the challenges remaining in the optimization and adoption of this treatment modality. A theme of the review is the complexity of PDT dosimetry due to the dynamic nature of the three essential components -- light, photosensitizer and oxygen. Considerable progress has been made in understanding the problem and in developing instruments to measure all three, so that optimization of individual PDT treatments is becoming a feasible target. The final section of the review introduces some new frontiers of research including low dose rate (metronomic) PDT, two-photon PDT, activatable PDT molecular beacons and nanoparticle-based PDT.

  6. Biophysical constraints on the computational capacity of biochemical signaling networks

    Science.gov (United States)

    Wang, Ching-Hao; Mehta, Pankaj

    Biophysics fundamentally constrains the computations that cells can carry out. Here, we derive fundamental bounds on the computational capacity of biochemical signaling networks that utilize post-translational modifications (e.g. phosphorylation). To do so, we combine ideas from the statistical physics of disordered systems and the observation by Tony Pawson and others that the biochemistry underlying protein-protein interaction networks is combinatorial and modular. Our results indicate that the computational capacity of signaling networks is severely limited by the energetics of binding and the need to achieve specificity. We relate our results to one of the theoretical pillars of statistical learning theory, Cover's theorem, which places bounds on the computational capacity of perceptrons. PM and CHW were supported by a Simons Investigator in the Mathematical Modeling of Living Systems Grant, and NIH Grant No. 1R35GM119461 (both to PM).

  7. Biophysical characterisation of GlycoPEGylated recombinant human factor VIIa

    DEFF Research Database (Denmark)

    Plesner, Bitten; Westh, Peter; Nielsen, Anders D.

    2011-01-01

    The effects of GlycoPEGylation on the structural, kinetic and thermal stability of recombinant human FVIIa were investigated using rFVIIa and linear 10 kDa and branched 40 kDa GlycoPEGylated® recombinant human FVIIa derivatives. The secondary and tertiary structure of rFVIIa measured by circular...... dichroism (CD) was maintained upon PEGylation. In contrast, the thermal and kinetic stability of rFVIIa was affected by GlycoPEGylation, as the apparent unfolding temperature Tm measured by differential scanning calorimetry (DSC) and the temperature of aggregation, Tagg, measured by light scattering (LS......) both increased with GlycoPEGylation. Both Tm and Tagg were independent of the molecular weight and the shape of the PEG chain. From the present biophysical characterisation it is concluded that after GlycoPEGylation, rFVIIa appears to be unaffected structurally (secondary and tertiary structure...

  8. 19th International School of Biophysics "Ettore Majorana"

    CERN Document Server

    Blank, M; Bioelectrochemistry III : Charge Separation across Biomembranes

    1988-01-01

    This book contains aseries of review papers related to the lectures given at the Third Course on Bioelectrochemistry held at Erice in November 1988, in the framework of the International School of Biophysics. The topics covered by this course, "Charge Separation Across Biomembranes, " deal with the electrochemical aspects of some basic phenomena in biological systems, such as transport of ions, ATP synthesis, formation and maintenance of ionic and protonic gradients. In the first part of the course some preliminary lectures introduce the students to the most basic phenomena and technical aspects of membrane bioelectrochemistry. The remaining part of the course is devoted to the description of a selected group of membrane-enzyme systems, capable of promoting, or exploiting, the processes of separation of electrically charged entities (electrons or ions) across the membrane barrier. These systems are systematically discussed both from a structural and functional point of view. The effort of the many dis...

  9. The physics, biophysics and technology of photodynamic therapy

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Brian C [Division of Biophysics and Bioimaging, Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, ON M5G 2M9 (Canada); Patterson, Michael S [Department of Medical Physics, Juravinski Cancer Centre and Department of Medical Physics and Applied Radiation Sciences, McMaster University, 699 Concession Street, Hamilton, ON L8V 5C2 (Canada)], E-mail: wilson@uhnres.utoronto.ca, E-mail: mike.patterson@jcc.hhsc.ca

    2008-05-07

    Photodynamic therapy (PDT) uses light-activated drugs to treat diseases ranging from cancer to age-related macular degeneration and antibiotic-resistant infections. This paper reviews the current status of PDT with an emphasis on the contributions of physics, biophysics and technology, and the challenges remaining in the optimization and adoption of this treatment modality. A theme of the review is the complexity of PDT dosimetry due to the dynamic nature of the three essential components-light, photosensitizer and oxygen. Considerable progress has been made in understanding the problem and in developing instruments to measure all three, so that optimization of individual PDT treatments is becoming a feasible target. The final section of the review introduces some new frontiers of research including low dose rate (metronomic) PDT, two-photon PDT, activatable PDT molecular beacons and nanoparticle-based PDT. (topical review)

  10. Drought propagation and its relation with catchment biophysical characteristics

    Science.gov (United States)

    Alvarez-Garreton, C. D.; Lara, A.; Garreaud, R. D.

    2016-12-01

    Droughts propagate in the hydrological cycle from meteorological to soil moisture to hydrological droughts. To understand the drivers of this process is of paramount importance since the economic and societal impacts in water resources are directly related with hydrological droughts (and not with meteorological droughts, which have been most studied). This research analyses drought characteristics over a large region and identify its main exogenous (climate forcing) and endogenous (biophysical characteristics such as land cover type and topography) explanatory factors. The study region is Chile, which covers seven major climatic subtypes according to Köppen system, it has unique geographic characteristics, very sharp topography and a wide range of landscapes and vegetation conditions. Meteorological and hydrological droughts (deficit in precipitation and streamflow, respectively) are characterized by their durations and standardized deficit volumes using a variable threshold method, over 300 representative catchments (located between 27°S and 50°S). To quantify the propagation from meteorological to hydrological drought, we propose a novel drought attenuation index (DAI), calculated as the ratio between the meteorological drought severity slope and the hydrological drought severity slope. DAI varies from zero (catchment that attenuates completely a meteorological drought) to one (the meteorological drought is fully propagated through the hydrological cycle). This novel index provides key (and comparable) information about drought propagation over a wide range of different catchments, which has been highlighted as a major research gap. Similar drought indicators across the wide range of catchments are then linked with catchment biophysical characteristics. A thorough compilation of land cover information (including the percentage of native forests, grass land, urban and industrial areas, glaciers, water bodies and no vegetated areas), catchment physical

  11. Biophysics at the Boundaries: The Next Problem Sets

    Science.gov (United States)

    Skolnick, Malcolm

    2009-03-01

    The interface between physics and biology is one of the fastest growing subfields of physics. As knowledge of such topics as cellular processes and complex ecological systems advances, researchers have found that progress in understanding these and other systems requires application of more quantitative approaches. Today, there is a growing demand for quantitative and computational skills in biological research and the commercialization of that research. The fragmented teaching of science in our universities still leaves biology outside the quantitative and mathematical culture that is the foundation of physics. This is particularly inopportune at a time when the needs for quantitative thinking about biological systems are exploding. More physicists should be encouraged to become active in research and development in the growing application fields of biophysics including molecular genetics, biomedical imaging, tissue generation and regeneration, drug development, prosthetics, neural and brain function, kinetics of nonequilibrium open biological systems, metabolic networks, biological transport processes, large-scale biochemical networks and stochastic processes in biochemical systems to name a few. In addition to moving into basic research in these areas, there is increasing opportunity for physicists in industry beginning with entrepreneurial roles in taking research results out of the laboratory and in the industries who perfect and market the inventions and developments that physicists produce. In this talk we will identify and discuss emerging opportunities for physicists in biophysical and biotechnological pursuits ranging from basic research through development of applications and commercialization of results. This will include discussion of the roles of physicists in non-traditional areas apart from academia such as patent law, financial analysis and regulatory science and the problem sets assigned in education and training that will enable future

  12. Biophysical mechanisms of endotoxin neutralization by cationic amphiphilic peptides.

    Science.gov (United States)

    Kaconis, Yani; Kowalski, Ina; Howe, Jörg; Brauser, Annemarie; Richter, Walter; Razquin-Olazarán, Iosu; Iñigo-Pestaña, Melania; Garidel, Patrick; Rössle, Manfred; Martinez de Tejada, Guillermo; Gutsmann, Thomas; Brandenburg, Klaus

    2011-06-08

    Bacterial endotoxins (lipopolysaccharides (LPS)) are strong elicitors of the human immune system by interacting with serum and membrane proteins such as lipopolysaccharide-binding protein (LBP) and CD14 with high specificity. At LPS concentrations as low as 0.3 ng/ml, such interactions may lead to severe pathophysiological effects, including sepsis and septic shock. One approach to inhibit an uncontrolled inflammatory reaction is the use of appropriate polycationic and amphiphilic antimicrobial peptides, here called synthetic anti-LPS peptides (SALPs). We designed various SALP structures and investigated their ability to inhibit LPS-induced cytokine secretion in vitro, their protective effect in a mouse model of sepsis, and their cytotoxicity in physiological human cells. Using a variety of biophysical techniques, we investigated selected SALPs with considerable differences in their biological responses to characterize and understand the mechanism of LPS inactivation by SALPs. Our investigations show that neutralization of LPS by peptides is associated with a fluidization of the LPS acyl chains, a strong exothermic Coulomb interaction between the two compounds, and a drastic change of the LPS aggregate type from cubic into multilamellar, with an increase in the aggregate sizes, inhibiting the binding of LBP and other mammalian proteins to the endotoxin. At the same time, peptide binding to phospholipids of human origin (e.g., phosphatidylcholine) does not cause essential structural changes, such as changes in membrane fluidity and bilayer structure. The absence of cytotoxicity is explained by the high specificity of the interaction of the peptides with LPS. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  13. High-field {sup 1}H NMR microscopy for fundamental biophysical research; Hochfeld {sup 1}H-NMR-Mikroskopie zur biophysikalischen Grundlagenforschung

    Energy Technology Data Exchange (ETDEWEB)

    Haddad, D.

    2003-08-08

    This work has a biophysical background and uses different examples to demonstrate the practical applicability of NMR-Microscopy in the medical and biological sector. Therefore, the different projects are feasibility studies which are used to compare the possibilities and advantages of NMR-Microscopy with other, established examination techniques. In detail, using MR-Microscopy, different living and fixed biological samples have been visualized non-invasively with high spatial resolution. The specific purpose of the studies ranged from the visualization of the invasion of tumor-spheroids into cell aggregates using T2 parameter maps (time constant of the spin-spin relaxation) to the three-dimensional display of the honey bee brain in the intact head capsule and the non-invasive visualization of the anatomy of prenatal dolphins. For all these projects, the non-invasive character of MR-experiments was of utmost importance. The tumor invasion was not to be disturbed by the measurements, the bee brain should be visualized as close to its true natural shape as possible and the examined dolphins represent rare museum specimens which should not be destroyed. The different samples were all imaged with the best possible spatial resolution which was either limited by the necessary signal-to-noise ratio (SNR) or the available scan time. In order to resolve single details and fine structures in the images, it was necessary to optimize the SNR as well as the contrast-to-noise ratio. To guarantee the necessary SNR, the measurements were performed on high field MR-spectrometers with resonance frequencies of 500 and 750 MHz.

  14. Biophysical detector for definition of anomalies in Semipalatinsk nuclear test site zone

    International Nuclear Information System (INIS)

    Sokolovskaya, E.V.; Inyushin, V.M.; Kalieva, Zh.A.

    2000-01-01

    With help of space aero-survey of thermodynamical anomaly (increase of land surface temperature) in Semipalatinsk test site zone is revealed. It was suggested that it is a result of recombination processes of Earth's plasma due to entropy increase in result of plasma fluctuations called by underground nuclear explosions. This hypothesis was checked by means of territory scanning around Semipalatinsk test site with help of biophysical detectors representing isolate fragments of bio-plasma of animal and vegetation origin. It was revealed that there are anomalies in Almaty-Semipalatinsk cities' beam of Ayaguz-Semipalatinsk zone and on Omsk-Semipalatinsk beam on Semenovka-Semipalatinsk section. During passing of areas in close proximity to the nuclear site an increase of micro-currents amplitude in 4-5 μA as well as irregular amplitude change are registered. Although anomalies make up 10 % from geo-plasma's micro-currents initial values, and this value can exert significant influence on human plasma homeostasis for persons living in anomalous regions. It is concluded that it is necessary research of non-radiation effects nature of underground nuclear explosions and its action on biological status of men, animals, plants and soils

  15. Use of Unpalatable Forages by Ruminants: The Influence of Experience with the Biophysical and Social Environment

    Directory of Open Access Journals (Sweden)

    Roberto A. Distel

    2018-04-01

    Full Text Available Unpalatable forage resources (low nutrient density, potentially toxic metabolites are widespread and represent a challenge for ruminant nutrition, health, and welfare. Our objective was to synthesize the role of biophysical and social experience on the use of unpalatable forages by ruminants, and highlight derived behavioural solutions for the well-being of soils, plants, and animals. Environmental experiences early in life modulate gene expression and promote learning, which alters morpho-physiological and psychological mechanisms that modify behavioural responses and change food and habitat selection. In this process, ruminants can become better adapted to the habitat where they are reared. Moreover, experiential learning provides flexibility in diet selection, which is critical for changing foraging environments. Learned associations between unpalatable and palatable foods, if ingested in appropriate amounts, sequence, and close temporal association, induce the development of preference for the former type of food. In this way, a more uniform use of resources can be achieved from the landscape level down to the individual plant, with the associated benefits to ecosystem integrity and stability. Ruminants can also learn the medicinal benefits of ingesting foods with toxins (e.g., condensed tannins and saponins with antiparasitic properties. This knowledge on behavioural processes can be translated into behavioural applications that provide low-cost solutions to many challenges that producers face in managing sustainable livestock production systems.

  16. Cerebellar supervised learning revisited: biophysical modeling and degrees-of-freedom control.

    Science.gov (United States)

    Kawato, Mitsuo; Kuroda, Shinya; Schweighofer, Nicolas

    2011-10-01

    The biophysical models of spike-timing-dependent plasticity have explored dynamics with molecular basis for such computational concepts as coincidence detection, synaptic eligibility trace, and Hebbian learning. They overall support different learning algorithms in different brain areas, especially supervised learning in the cerebellum. Because a single spine is physically very small, chemical reactions at it are essentially stochastic, and thus sensitivity-longevity dilemma exists in the synaptic memory. Here, the cascade of excitable and bistable dynamics is proposed to overcome this difficulty. All kinds of learning algorithms in different brain regions confront with difficult generalization problems. For resolution of this issue, the control of the degrees-of-freedom can be realized by changing synchronicity of neural firing. Especially, for cerebellar supervised learning, the triangle closed-loop circuit consisting of Purkinje cells, the inferior olive nucleus, and the cerebellar nucleus is proposed as a circuit to optimally control synchronous firing and degrees-of-freedom in learning. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. A Multi-Sensor Approach to Enhance the Prediction of Mangrove Biophysical Characteristics in Chilika Lagoon and Bhitarkanika Wildlife Sanctuary, Odisha, India

    Science.gov (United States)

    Kumar, A.; Bledsoe, R.; Mishra, D. R.; Cameron, C.; Dahal, S.; Remillard, C.; Stone, A.; Stupp, P.

    2017-12-01

    Mangroves, one of the most productive ecosystems on Earth, play a major role in coastal ecosystem processes from mitigating erosion to acting as a barrier against tidal and storm surges associated with tropical cyclones. India has about 5 % of the world's mangrove vegetation, and over half of which is found along the east coast of the country. Chilika Lagoon and Bhitarkanika Wildlife Sanctuary are Ramsar sites of international wetland importance, situated in the state of Odisha along the east coast of India. Chilika Lagoon holds three small, but distinct mangrove patches, while Bhitarkanika Wildlife Sanctuary has several large, dense patches of mangroves. There is growing concern for the effective management and conservation of these mangrove forests. This study demonstrated the use of a suite of satellite data (Terra, Landsat, and Sentinel-1) for meeting the following objectives: 1. Derive a long-term spatio-temporal phenological maps of the biophysical parameters (chlorophyll, leaf area index, gross primary productivity, and evapotranspiration); 2. Analyze long-term spatio-temporal variability of physical and meteorological parameters; 3. Document decadal changes in mangroves area estimates starting from 1995 to 2017 using Landsat and radar data. The time series developed in this study revealed a phenological pattern for mangrove biophysical characteristics. Historical analysis of land cover maps indicated decrease in dense mangrove area and increase in open mangrove area and fragmentation. The results of this study will be used as an efficient biophysical mapping and monitoring protocol for mangrove forests in restoration decision-making.

  18. Can Whole-Body Cryotherapy with Subsequent Kinesiotherapy Procedures in Closed Type Cryogenic Chamber Improve BASDAI, BASFI, and Some Spine Mobility Parameters and Decrease Pain Intensity in Patients with Ankylosing Spondylitis?

    Science.gov (United States)

    Stanek, Agata; Cholewka, Armand; Gadula, Jolanta; Drzazga, Zofia; Sieron, Aleksander; Sieron-Stoltny, Karolina

    2015-01-01

    The present study investigated whether whole-body cryotherapy (WBC) procedures could potentially have more beneficial effects on index of BASDAI and BASFI, pain intensity, and spine mobility parameters: Ott test, modified Schober test, chest expansion in ankylosing spondylitis (AS) patients, than kinesiotherapy procedures used separately. AS patients were exposed to a cycle of WBC procedures lasting 3 minutes a day, with a subsequent 60 minutes of kinesiotherapy or 60 minutes of kinesiotherapy only, for 10 consecutive days excluding weekend. After the completion of the cycle of WBC procedures with subsequent kinesiotherapy in the AS patients, BASDAI index decreased about 40% in comparison with the input value, whereas in the group of patients who received only kinesiotherapy it decreased only about 15% in comparison with the input value. After the completion of the treatment in the WBC group, BASFI index decreased about 30% in comparison with the input value, whereas in the kinesiotherapy group it only decreased about 16% in comparison with the input value. The important conclusion was that, in WBC group with subsequent kinesiotherapy, we observed on average about twice better results than in the group treated only by kinesiotherapy. PMID:26273618

  19. A Review on the Role of Vibrational Spectroscopy as An Analytical Method to Measure Starch Biochemical and Biophysical Properties in Cereals and Starchy Foods

    Directory of Open Access Journals (Sweden)

    D. Cozzolino

    2014-12-01

    Full Text Available Starch is the major component of cereal grains and starchy foods, and changes in its biophysical and biochemical properties (e.g., amylose, amylopectin, pasting, gelatinization, viscosity will have a direct effect on its end use properties (e.g., bread, malt, polymers. The use of rapid and non-destructive methods to study and monitor starch properties, such as gelatinization, retrogradation, water absorption in cereals and starchy foods, is of great interest in order to improve and assess their quality. In recent years, near infrared reflectance (NIR and mid infrared (MIR spectroscopy have been explored to predict several quality parameters, such as those generated by instrumental methods commonly used in routine analysis like the rapid visco analyser (RVA or viscometers. In this review, applications of both NIR and MIR spectroscopy to measure and monitor starch biochemical (amylose, amylopectin, starch and biophysical properties (e.g., pasting properties will be presented and discussed.

  20. Establishment of a biophysical model to optimize endoscopic targeting of magnetic nanoparticles for cancer treatment

    Directory of Open Access Journals (Sweden)

    Roeth AA

    2017-08-01

    Full Text Available Anjali A Roeth,1,* Ioana Slabu,2,* Martin Baumann,2 Patrick H Alizai,1 Maximilian Schmeding,1 Gernot Guentherodt,3 Thomas Schmitz-Rode,2 Ulf P Neumann1 1Department of General, Visceral and Transplant Surgery, University Hospital RWTH Aachen, 2Institute of Applied Medical Engineering, Helmholtz-Institute Aachen, RWTH Aachen, Aachen, 3Institute of Physics A, RWTH Aachen University, Aachen, Germany *These authors contributed equally to this work Abstract: Superparamagnetic iron oxide nanoparticles (SPION may be used for local tumor treatment by coupling them to a drug and accumulating them locally with magnetic field traps, that is, a combination of permanent magnets and coils. Thereafter, an alternating magnetic field generates heat which may be used to release the thermosensitively bound drug and for hyperthermia. Until today, only superficial tumors can be treated with this method. Our aim was to transfer this method into an endoscopic setting to also reach the majority of tumors located inside the body. To find the ideal endoscopic magnetic field trap, which accumulates the most SPION, we first developed a biophysical model considering anatomical as well as physical conditions. Entities of choice were esophageal and prostate cancer. The magnetic susceptibilities of different porcine and rat tissues were measured with a superconducting quantum interference device. All tissues showed diamagnetic behavior. The evaluation of clinical data (computed tomography scan, endosonography, surgical reports, pathological evaluation of patients gave insight into the topographical relationship between the tumor and its surroundings. Both were used to establish the biophysical model of the tumors and their surroundings, closely mirroring the clinical situation, in which we could virtually design, place and evaluate different electromagnetic coil configurations to find optimized magnetic field traps for each tumor entity. By simulation, we could show that the

  1. Building biophysics in mid-century China: the University of Science and Technology of China.

    Science.gov (United States)

    Luk, Yi Lai Christine

    2015-01-01

    Biophysics has been either an independent discipline or an element of another discipline in the United States, but it has always been recognized as a stand-alone discipline in the People's Republic of China (PRC) since 1949. To inquire into this apparent divergence, this paper investigates the formational history of biophysics in China by examining the early institutional history of one of the best-known and prestigious science and technology universities in the PRC, the University of Science and Technology of China (USTC). By showing how the university and its biophysics program co-evolved with national priorities from the school's founding in 1958 to the eve of the Cultural Revolution in 1966, the purpose of this paper is to assess the development of a scientific discipline in the context of national demands and institutional politics. Specific materials for analysis include the school's admission policies, curricula, students' dissertations, and research program. To further contextualize the institutional setting of Chinese biophysics, this paper begins with a general history of proto-biophysical institutions in China during the Nationalist-Communist transitional years. This paper could be of interest to historians wanting to know more about the origin of the biophysics profession in China, and in particular how research areas that constitute biophysics changed in tandem with socio-political contingencies.

  2. CREB Overexpression Ameliorates Age-related Behavioral and Biophysical Deficits

    Science.gov (United States)

    Yu, Xiao-Wen

    Age-related cognitive deficits are observed in both humans and animals. Yet, the molecular mechanisms underlying these deficits are not yet fully elucidated. In aged animals, a decrease in intrinsic excitability of pyramidal neurons from the CA1 sub-region of hippocampus is believed to contribute to age-related cognitive impairments, but the molecular mechanism(s) that modulate both these factors has yet to be identified. Increasing activity of the transcription factor cAMP response element-binding protein (CREB) in young adult rodents has been shown to facilitate cognition, and increase intrinsic excitability of their neurons. However, how CREB changes with age, and how that impacts cognition in aged animals, is not clear. Therefore, we first systematically characterized age- and training-related changes in CREB levels in dorsal hippocampus. At a remote time point after undergoing behavioral training, levels of total CREB and activated CREB (phosphorylated at S133, pCREB) were measured in both young and aged rats. We found that pCREB, but not total CREB was significantly reduced in dorsal CA1 of aged rats. Importantly, levels of pCREB were found to be positively correlated with short-term spatial memory in both young and aged rats i.e. higher pCREB in dorsal CA1 was associated with better spatial memory. These findings indicate that an age-related deficit in CREB activity may contribute to the development of age-related cognitive deficits. However, it was still unclear if increasing CREB activity would be sufficient to ameliorate age-related cognitive, and biophysical deficits. To address this question, we virally overexpressed CREB in CA1, where we found the age-related deficit. Young and aged rats received control or CREB virus, and underwent water maze training. While control aged animals exhibited deficits in long-term spatial memory, aged animals with CREB overexpression performed at levels comparable to young animals. Concurrently, aged neurons

  3. Constructing Precisely Computing Networks with Biophysical Spiking Neurons.

    Science.gov (United States)

    Schwemmer, Michael A; Fairhall, Adrienne L; Denéve, Sophie; Shea-Brown, Eric T

    2015-07-15

    While spike timing has been shown to carry detailed stimulus information at the sensory periphery, its possible role in network computation is less clear. Most models of computation by neural networks are based on population firing rates. In equivalent spiking implementations, firing is assumed to be random such that averaging across populations of neurons recovers the rate-based approach. Recently, however, Denéve and colleagues have suggested that the spiking behavior of neurons may be fundamental to how neuronal networks compute, with precise spike timing determined by each neuron's contribution to producing the desired output (Boerlin and Denéve, 2011; Boerlin et al., 2013). By postulating that each neuron fires to reduce the error in the network's output, it was demonstrated that linear computations can be performed by networks of integrate-and-fire neurons that communicate through instantaneous synapses. This left open, however, the possibility that realistic networks, with conductance-based neurons with subthreshold nonlinearity and the slower timescales of biophysical synapses, may not fit into this framework. Here, we show how the spike-based approach can be extended to biophysically plausible networks. We then show that our network reproduces a number of key features of cortical networks including irregular and Poisson-like spike times and a tight balance between excitation and inhibition. Lastly, we discuss how the behavior of our model scales with network size or with the number of neurons "recorded" from a larger computing network. These results significantly increase the biological plausibility of the spike-based approach to network computation. We derive a network of neurons with standard spike-generating currents and synapses with realistic timescales that computes based upon the principle that the precise timing of each spike is important for the computation. We then show that our network reproduces a number of key features of cortical networks

  4. School Closings in Philadelphia

    Science.gov (United States)

    Jack, James; Sludden, John

    2013-01-01

    In 2012, the School District of Philadelphia closed six schools. In 2013, it closed 24. The closure of 30 schools has occurred amid a financial crisis, headlined by the district's $1.35 billion deficit. School closures are one piece of the district's plan to cut expenditures and close its budget gap. The closures are also intended to make…

  5. The Role of Social Constructions and Biophysical Attributes of the Environment in Decision-Making in the Context of Biofuels and Rubber Production Partnership Regimes in Upland Philippines

    Science.gov (United States)

    Montefrio, M. F.

    2012-12-01

    Burgeoning attention in biofuels and natural rubber has spurred interest among governments and private companies in integrating marginalized communities into global commodity markets. Upland farmers from diverse cultural backgrounds and biophysical settings today are deciding whether to agree with partnership proposals from governments and private firms to grow biofuels and natural rubber. In this paper, I examine whether upland farmers' socio-environmental constructions (evaluative beliefs, place satisfaction, and ecological worldviews) and the actual biophysical attributes (land cover and soil types) of upland environments, respectively, function as significant predictors of the intent and decisions of indigenous and non-indigenous farmers to cooperate with government and private actors to establish certain biofuel crops and natural rubber production systems in Palawan, Philippines. Drawing from ethnography and statistical analysis of household surveys, I propose that social constructions and the biophysical attributes of the environment are closely related with each other and in turn both influence individual decision-making behavior in resource-based production partnership regimes. This has significant implications on the resilience of socio-ecological systems, particularly agro-ecosystems, as certain upland farmers prefer to engage in intensive, monocrop production of biofuels and natural rubber on relatively more biodiverse areas, such as secondary forests and traditional shifting cultivation lands. The study aims to advance new institutional theories of resource management, particularly Ostrom's Institutional Analysis and Development and Socio-Ecological Systems frameworks, and scholarship on environmental decision-making in the context of collective action.

  6. A fully synthetic human Fab antibody library based on fixed VH/VL framework pairings with favorable biophysical properties

    Science.gov (United States)

    Tiller, Thomas; Schuster, Ingrid; Deppe, Dorothée; Siegers, Katja; Strohner, Ralf; Herrmann, Tanja; Berenguer, Marion; Poujol, Dominique; Stehle, Jennifer; Stark, Yvonne; Heßling, Martin; Daubert, Daniela; Felderer, Karin; Kaden, Stefan; Kölln, Johanna; Enzelberger, Markus; Urlinger, Stefanie

    2013-01-01

    This report describes the design, generation and testing of Ylanthia, a fully synthetic human Fab antibody library with 1.3E+11 clones. Ylanthia comprises 36 fixed immunoglobulin (Ig) variable heavy (VH)/variable light (VL) chain pairs, which cover a broad range of canonical complementarity-determining region (CDR) structures. The variable Ig heavy and Ig light (VH/VL) chain pairs were selected for biophysical characteristics favorable to manufacturing and development. The selection process included multiple parameters, e.g., assessment of protein expression yield, thermal stability and aggregation propensity in fragment antigen binding (Fab) and IgG1 formats, and relative Fab display rate on phage. The framework regions are fixed and the diversified CDRs were designed based on a systematic analysis of a large set of rearranged human antibody sequences. Care was taken to minimize the occurrence of potential posttranslational modification sites within the CDRs. Phage selection was performed against various antigens and unique antibodies with excellent biophysical properties were isolated. Our results confirm that quality can be built into an antibody library by prudent selection of unmodified, fully human VH/VL pairs as scaffolds. PMID:23571156

  7. Ecosystem biophysical memory in the southwestern North America climate system

    International Nuclear Information System (INIS)

    Forzieri, G; Feyen, L; Vivoni, E R

    2013-01-01

    To elucidate the potential role of vegetation to act as a memory source in the southwestern North America climate system, we explore correlation structures of remotely sensed vegetation dynamics with precipitation, temperature and teleconnection indices over 1982–2006 for six ecoregions. We found that lagged correlations between vegetation dynamics and climate variables are modulated by the dominance of monsoonal or Mediterranean regimes and ecosystem-specific physiological processes. Subtropical and tropical ecosystems exhibit a one month lag positive correlation with precipitation, a zero- to one-month lag negative correlation with temperature, and modest negative effects of sea surface temperature (SST). Mountain forests have a zero month lag negative correlation with precipitation, a zero–one month lag negative correlation with temperature, and no significant correlation with SSTs. Deserts show a strong one–four month lag positive correlation with precipitation, a low zero–two month lag negative correlation with temperature, and a high four–eight month lag positive correlation with SSTs. The ecoregion-specific biophysical memories identified offer an opportunity to improve the predictability of land–atmosphere interactions and vegetation feedbacks onto climate. (letter)

  8. Biophysical and biological meanings of healthspan from C. elegans cohort

    International Nuclear Information System (INIS)

    Suda, Hitoshi

    2014-01-01

    Highlights: • We focus on a third factor, noise, as well as on genetic and environmental factors. • C. elegans fed a healthy food had an extended healthspan as compared to those fed a conventional diet. • An amplification of ATP noise was clearly evident from around the onset of biodemographic aging. • The extension of timing of noise amplification may contribute to effectively extending the healthspan. • The same mechanism of the mean lifespan extension in C. elegans may be realized in humans. - Abstract: Lifespan among individuals ranges widely in organisms from yeast to mammals, even in an isogenic cohort born in a nearly uniform environment. Needless to say, genetic and environmental factors are essential for aging and lifespan, but in addition, a third factor or the existence of a stochastic element must be reflected in aging and lifespan. An essential point is that lifespan or aging is an unpredictable phenomenon. The present study focuses on elucidating the biophysical and biological meanings of healthspan that latently indwells a stochastic nature. To perform this purpose, the nematode Caenorhabditis elegans served as a model animal. C. elegans fed a healthy food had an extended healthspan as compared to those fed a conventional diet. Then, utilizing this phenomenon, we clarified a mechanism of healthspan extension by measuring the single-worm ATP and estimating the ATP noise (or the variability of the ATP content) among individual worms and by quantitatively analyzing biodemographic data with the lifespan equation that was derived from a fluctuation theory

  9. A Biophysical Neural Model To Describe Spatial Visual Attention

    International Nuclear Information System (INIS)

    Hugues, Etienne; Jose, Jorge V.

    2008-01-01

    Visual scenes have enormous spatial and temporal information that are transduced into neural spike trains. Psychophysical experiments indicate that only a small portion of a spatial image is consciously accessible. Electrophysiological experiments in behaving monkeys have revealed a number of modulations of the neural activity in special visual area known as V4, when the animal is paying attention directly towards a particular stimulus location. The nature of the attentional input to V4, however, remains unknown as well as to the mechanisms responsible for these modulations. We use a biophysical neural network model of V4 to address these issues. We first constrain our model to reproduce the experimental results obtained for different external stimulus configurations and without paying attention. To reproduce the known neuronal response variability, we found that the neurons should receive about equal, or balanced, levels of excitatory and inhibitory inputs and whose levels are high as they are in in vivo conditions. Next we consider attentional inputs that can induce and reproduce the observed spiking modulations. We also elucidate the role played by the neural network to generate these modulations

  10. Unofficial Road Building in the Amazon: Socioeconomic and Biophysical Explanations

    Science.gov (United States)

    Perz, Stephen G.; Caldas, Marcellus M.; Arima, Eugenio; Walker, Robert J.

    2007-01-01

    Roads have manifold social and environmental impacts, including regional development, social conflicts and habitat fragmentation. 'Road ecology' has emerged as an approach to evaluate the various ecological and hydrological impacts of roads. This article aims to complement road ecology by examining the socio-spatial processes of road building itself. Focusing on the Brazilian Amazon, a heavily-studied context due to forest fragmentation by roads, the authors consider non-state social actors who build 'unofficial roads' for the purpose of gaining access to natural resources to support livelihoods and community development. They examine four case studies of roads with distinct histories in order to explain the socio-spatial processes behind road building in terms of profit maximization, land tenure claims, co-operative and conflictive political ecologies, and constraints as well as opportunities afforded by the biophysical environment. The study cases illustrate the need for a multi-pronged theoretical approach to understanding road building, and call for more attention to the role of non-state actors in unofficial road construction.

  11. Biophysical Characterization of α-Synuclein and Rotenone Interaction

    Directory of Open Access Journals (Sweden)

    Anthony L. Fink

    2013-09-01

    Full Text Available Previous studies revealed that pesticides interact with α-synuclein and accelerate the rate of fibrillation. These results are consistent with the prevailing hypothesis that the direct interaction of α-synuclein with pesticides is one of many suspected factors leading to α-synuclein fibrillation and ultimately to Parkinson’s disease. In this study, the biophysical properties and fibrillation kinetics of α-synuclein in the presence of rotenone were investigated and, more specifically, the effects of rotenone on the early-stage misfolded forms of α-synuclein were considered. The thioflavine T (ThT fluorescence assay studies provide evidence that early-phase misfolded α-synuclein forms are affected by rotenone and that the fibrillation process is accelerated. Further characterization by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR shows that rotenone increases the amount of ordered secondary structure in this intrinsically disordered protein. Morphological characterization by transmission electron microscopy (TEM and atomic force microscopy (AFM provide visualization of the differences in the aggregated α-synuclein species developing during the early kinetics of the fibrillation process in the absence and presence of rotenone. We believe that these data provide useful information for a better understanding of the molecular basis of rotenone-induced misfolding and aggregation of α-synuclein.

  12. Universal buffers for use in biochemistry and biophysical experiments

    Directory of Open Access Journals (Sweden)

    Dewey Brooke

    2015-08-01

    Full Text Available The use of buffers that mimic biological solutions is a foundation of biochemical and biophysical studies. However, buffering agents have both specific and nonspecific interactions with proteins. Buffer molecules can induce changes in conformational equilibria, dynamic behavior, and catalytic properties merely by their presence in solution. This effect is of concern because many of the standard experiments used to investigate protein structure and function involve changing solution conditions such as pH and/or temperature. In experiments in which pH is varied, it is common practice to switch buffering agents so that the pH is within the working range of the weak acid and conjugate base. If multiple buffers are used, it is not always possible to decouple buffer induced change from pH or temperature induced change. We have developed a series of mixed biological buffers for protein analysis that can be used across a broad pH range, are compatible with biologically relevant metal ions, and avoid complications that may arise from changing the small molecule composition of buffers when pH is used as an experimental variable.

  13. Editorial: The Sackler International Prize in Biophysical Sciences

    Science.gov (United States)

    Frydman, Lucio

    2018-02-01

    The Raymond and Beverly Sackler International Prize is awarded alternatively in the fields of Biophysics, Chemistry and Physics on a yearly basis, by Tel Aviv University. The price is intended to encourage dedication to science, originality and excellence, by rewarding outstanding scientists under 45 years of age, with a total purse of 100,000. The 2016 Raymond and Beverly Sackler Prize was awarded in the field of Magnetic Resonance last February in a festive symposium, to three excellent researchers: Professor John Morton (University College London), Professor Guido Pintacuda (Ecole Normale Supérieure de Lyon and CNRS), and Professor Charalampos Kalodimos (at the time at the University of Minnesota). John was recognized for his novel contributions to quantum information processing, by means of a range of highly elegant physical phenomena involving both NMR and EPR. Guido was recognized for his methodological advances in solid state NMR spectroscopy, including advances in proton detection under ultrafast MAS at ultrahigh magnetic field, and for his insightful applications to challenging biological systems. While Charalampos (Babis) was recognized for beautifully detailed characterizations of structure, function, and dynamics in challenging and important biological systems through solution NMR spectroscopy.

  14. IS THERE ANY ASSOCIATION BETWEEN MATERNAL DEPRESSION AND BIOPHYSICAL PROFILE?

    Directory of Open Access Journals (Sweden)

    M Z Pezeshki

    2008-11-01

    Full Text Available "nMother's mental health status during pregnancy has important effects on fetal growth and development. However, there are few studies concerning association of maternal depression and biophysical profile (BPP of the fetus. We performed this research to know if maternal depression has any association with fetal BPP score. For measuring depression, Farsi version of Patient Health Questionnaire-9 (PHQ-9 was completed. A total of 100 pregnant women in their third trimester (>24 weeks who had not hyperthyroidism, hypothyroidism, eclampsia and preeclampsia, fever, infection, diabetes or a fetus with intrauterine growth retardation (IUGR and were not using any medication entered the study. Spearman correlation coefficient between the score of PHQ-9 questionnaire and BPP score was -0.08 (P = 0.43. Based on Kruskal Wallis test, there was no difference in BPP score of depressed and nondepressed women (P = 0.65. We found no relationship between maternal depression and BPP score in third trimester of pregnancy. Further studies for elucidating neuro-hormonal mechanisms related to the result of our study are suggested

  15. Energy efficient neural stimulation: coupling circuit design and membrane biophysics.

    Science.gov (United States)

    Foutz, Thomas J; Ackermann, D Michael; Kilgore, Kevin L; McIntyre, Cameron C

    2012-01-01

    The delivery of therapeutic levels of electrical current to neural tissue is a well-established treatment for numerous indications such as Parkinson's disease and chronic pain. While the neuromodulation medical device industry has experienced steady clinical growth over the last two decades, much of the core technology underlying implanted pulse generators remain unchanged. In this study we propose some new methods for achieving increased energy-efficiency during neural stimulation. The first method exploits the biophysical features of excitable tissue through the use of a centered-triangular stimulation waveform. Neural activation with this waveform is achieved with a statistically significant reduction in energy compared to traditional rectangular waveforms. The second method demonstrates energy savings that could be achieved by advanced circuitry design. We show that the traditional practice of using a fixed compliance voltage for constant-current stimulation results in substantial energy loss. A portion of this energy can be recuperated by adjusting the compliance voltage to real-time requirements. Lastly, we demonstrate the potential impact of axon fiber diameter on defining the energy-optimal pulse-width for stimulation. When designing implantable pulse generators for energy efficiency, we propose that the future combination of a variable compliance system, a centered-triangular stimulus waveform, and an axon diameter specific stimulation pulse-width has great potential to reduce energy consumption and prolong battery life in neuromodulation devices.

  16. Biophysical studies related to energy generation: Progress report

    International Nuclear Information System (INIS)

    Green, A.E.S.

    1988-01-01

    This report covers work subsequent to our previous report of December 24, 1986. At that time we were groping to find relationships between vibrational and rotational electron impact cross sections in the vapor and liquid phases of water. Having reached an impass within the radiological literature, we drew upon the atmospheric, oceanographic and flame radiation literatures. Here a much broader body of excitation energy and intensity data related to the vibrational and rotational excitation of water in the vapor phases and liquid phases enabled us to identify certain ''big bands'' of H 2 O. These bands account for the major infrared absorption features observed in atmospheric transmission studies as well as important spectral radiation features observed in hydrocarbon combustion. Related liquid phase-gas phase involvement also entered our work on co-combustion of biomass and waste, and natural gas in studies directed toward contributing to the solution of national energy-environmental and economic problems. Attachments to this report include our published works, submitted works, and in complete studies related to radiological, atmospheric, and combustion studies which encompass biophysical studies related to energy generation and which have a common thread involving water in liquid and vapor form. These works are tied together in this brief report, along with some comments on trends in science and technology which they might illustrate

  17. Biophysical model of prokaryotic diversity in geothermal hot springs.

    Science.gov (United States)

    Klales, Anna; Duncan, James; Nett, Elizabeth Janus; Kane, Suzanne Amador

    2012-02-01

    Recent studies of photosynthetic bacteria living in geothermal hot spring environments have revealed surprisingly complex ecosystems with an unexpected level of genetic diversity. One case of particular interest involves the distribution along hot spring thermal gradients of genetically distinct bacterial strains that differ in their preferred temperatures for reproduction and photosynthesis. In such systems, a single variable, temperature, defines the relevant environmental variation. In spite of this, each region along the thermal gradient exhibits multiple strains of photosynthetic bacteria adapted to several distinct thermal optima, rather than a single thermal strain adapted to the local environmental temperature. Here we analyze microbiology data from several ecological studies to show that the thermal distribution data exhibit several universal features independent of location and specific bacterial strain. These include the distribution of optimal temperatures of different thermal strains and the functional dependence of the net population density on temperature. We present a simple population dynamics model of these systems that is highly constrained by biophysical data and by physical features of the environment. This model can explain in detail the observed thermal population distributions, as well as certain features of population dynamics observed in laboratory studies of the same organisms. © 2012 American Physical Society

  18. Energy efficient neural stimulation: coupling circuit design and membrane biophysics.

    Directory of Open Access Journals (Sweden)

    Thomas J Foutz

    Full Text Available The delivery of therapeutic levels of electrical current to neural tissue is a well-established treatment for numerous indications such as Parkinson's disease and chronic pain. While the neuromodulation medical device industry has experienced steady clinical growth over the last two decades, much of the core technology underlying implanted pulse generators remain unchanged. In this study we propose some new methods for achieving increased energy-efficiency during neural stimulation. The first method exploits the biophysical features of excitable tissue through the use of a centered-triangular stimulation waveform. Neural activation with this waveform is achieved with a statistically significant reduction in energy compared to traditional rectangular waveforms. The second method demonstrates energy savings that could be achieved by advanced circuitry design. We show that the traditional practice of using a fixed compliance voltage for constant-current stimulation results in substantial energy loss. A portion of this energy can be recuperated by adjusting the compliance voltage to real-time requirements. Lastly, we demonstrate the potential impact of axon fiber diameter on defining the energy-optimal pulse-width for stimulation. When designing implantable pulse generators for energy efficiency, we propose that the future combination of a variable compliance system, a centered-triangular stimulus waveform, and an axon diameter specific stimulation pulse-width has great potential to reduce energy consumption and prolong battery life in neuromodulation devices.

  19. Biophysical and biological meanings of healthspan from C. elegans cohort

    Energy Technology Data Exchange (ETDEWEB)

    Suda, Hitoshi, E-mail: suda@tsc.u-tokai.ac.jp

    2014-09-12

    Highlights: • We focus on a third factor, noise, as well as on genetic and environmental factors. • C. elegans fed a healthy food had an extended healthspan as compared to those fed a conventional diet. • An amplification of ATP noise was clearly evident from around the onset of biodemographic aging. • The extension of timing of noise amplification may contribute to effectively extending the healthspan. • The same mechanism of the mean lifespan extension in C. elegans may be realized in humans. - Abstract: Lifespan among individuals ranges widely in organisms from yeast to mammals, even in an isogenic cohort born in a nearly uniform environment. Needless to say, genetic and environmental factors are essential for aging and lifespan, but in addition, a third factor or the existence of a stochastic element must be reflected in aging and lifespan. An essential point is that lifespan or aging is an unpredictable phenomenon. The present study focuses on elucidating the biophysical and biological meanings of healthspan that latently indwells a stochastic nature. To perform this purpose, the nematode Caenorhabditis elegans served as a model animal. C. elegans fed a healthy food had an extended healthspan as compared to those fed a conventional diet. Then, utilizing this phenomenon, we clarified a mechanism of healthspan extension by measuring the single-worm ATP and estimating the ATP noise (or the variability of the ATP content) among individual worms and by quantitatively analyzing biodemographic data with the lifespan equation that was derived from a fluctuation theory.

  20. Biophysical induction of vascular smooth muscle cell podosomes.

    Directory of Open Access Journals (Sweden)

    Na Young Kim

    Full Text Available Vascular smooth muscle cell (VSMC migration and matrix degradation occurs with intimal hyperplasia associated with atherosclerosis, vascular injury, and restenosis. One proposed mechanism by which VSMCs degrade matrix is through the use of podosomes, transient actin-based structures that are thought to play a role in extracellular matrix degradation by creating localized sites of matrix metalloproteinase (MMP secretion. To date, podosomes in VSMCs have largely been studied by stimulating cells with phorbol esters, such as phorbol 12,13-dibutyrate (PDBu, however little is known about the physiological cues that drive podosome formation. We present the first evidence that physiological, physical stimuli mimicking cues present within the microenvironment of diseased arteries can induce podosome formation in VSMCs. Both microtopographical cues and imposed pressure mimicking stage II hypertension induce podosome formation in A7R5 rat aortic smooth muscle cells. Moreover, wounding using a scratch assay induces podosomes at the leading edge of VSMCs. Notably the effect of each of these biophysical stimuli on podosome stimulation can be inhibited using a Src inhibitor. Together, these data indicate that physical cues can induce podosome formation in VSMCs.

  1. The interface of protein structure, protein biophysics, and molecular evolution

    Science.gov (United States)

    Liberles, David A; Teichmann, Sarah A; Bahar, Ivet; Bastolla, Ugo; Bloom, Jesse; Bornberg-Bauer, Erich; Colwell, Lucy J; de Koning, A P Jason; Dokholyan, Nikolay V; Echave, Julian; Elofsson, Arne; Gerloff, Dietlind L; Goldstein, Richard A; Grahnen, Johan A; Holder, Mark T; Lakner, Clemens; Lartillot, Nicholas; Lovell, Simon C; Naylor, Gavin; Perica, Tina; Pollock, David D; Pupko, Tal; Regan, Lynne; Roger, Andrew; Rubinstein, Nimrod; Shakhnovich, Eugene; Sjölander, Kimmen; Sunyaev, Shamil; Teufel, Ashley I; Thorne, Jeffrey L; Thornton, Joseph W; Weinreich, Daniel M; Whelan, Simon

    2012-01-01

    Abstract The interface of protein structural biology, protein biophysics, molecular evolution, and molecular population genetics forms the foundations for a mechanistic understanding of many aspects of protein biochemistry. Current efforts in interdisciplinary protein modeling are in their infancy and the state-of-the art of such models is described. Beyond the relationship between amino acid substitution and static protein structure, protein function, and corresponding organismal fitness, other considerations are also discussed. More complex mutational processes such as insertion and deletion and domain rearrangements and even circular permutations should be evaluated. The role of intrinsically disordered proteins is still controversial, but may be increasingly important to consider. Protein geometry and protein dynamics as a deviation from static considerations of protein structure are also important. Protein expression level is known to be a major determinant of evolutionary rate and several considerations including selection at the mRNA level and the role of interaction specificity are discussed. Lastly, the relationship between modeling and needed high-throughput experimental data as well as experimental examination of protein evolution using ancestral sequence resurrection and in vitro biochemistry are presented, towards an aim of ultimately generating better models for biological inference and prediction. PMID:22528593

  2. Symposium on Biophysics and Physiology of Biological Transport

    CERN Document Server

    Capraro, V; Porter, K; Robertson, J

    1967-01-01

    The study of cell membranes began to attract increasing interest before the turn of the present century with the observations of 0 verton. Since that time many investigators have become interested in the broad problem of structure and function of the membrane and today we find ourselVes at a stage in which several branches of research, particularly physical chemistry, biochemistry, biophysics, physiology and pharmacology have come together, leading to the possibility of obtaining a better perspective of the overall problems. The purpose of this Symposium was to assemble in an orderly sequence representations of the knowledge of membranes achieved to date in the areas of the various disciplines. It was thought that to bring together many points of view on a problem should allow the conferees to see better what had been accomplished, what has been overlooked and what needs further development. It is to be hoped that efforts of this type have and will fulfill the desired purpose. This volume contains the majorit...

  3. Biophysical properties and computational modeling of calcium spikes in serotonergic neurons of the dorsal raphe nucleus.

    Science.gov (United States)

    Tuckwell, Henry C

    2013-06-01

    Serotonergic neurons of the dorsal raphe nuclei, with their extensive innervation of nearly the whole brain have important modulatory effects on many cognitive and physiological processes. They play important roles in clinical depression and other psychiatric disorders. In order to quantify the effects of serotonergic transmission on target cells it is desirable to construct computational models and to this end these it is necessary to have details of the biophysical and spike properties of the serotonergic neurons. Here several basic properties are reviewed with data from several studies since the 1960s to the present. The quantities included are input resistance, resting membrane potential, membrane time constant, firing rate, spike duration, spike and afterhyperpolarization (AHP) amplitude, spike threshold, cell capacitance, soma and somadendritic areas. The action potentials of these cells are normally triggered by a combination of sodium and calcium currents which may result in autonomous pacemaker activity. We here analyse the mechanisms of high-threshold calcium spikes which have been demonstrated in these cells the presence of TTX (tetrodotoxin). The parameters for calcium dynamics required to give calcium spikes are quite different from those for regular spiking which suggests the involvement of restricted parts of the soma-dendritic surface as has been found, for example, in hippocampal neurons. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  4. A biophysical process based approach for estimating net primary production using satellite and ground observations

    Science.gov (United States)

    Choudhury, Bhaskar J.

    An approach is presented for calculating interannual variation of net primary production (C) of terrestrial plant communities at regional scale using satellite and ground measurements. C has been calculated as the difference of gross photosynthesis (A g) and respiration (R), recognizing that different biophysical factors exert major control on these two processes. A g has been expressed as the product of radiation use efficiency for gross photosynthesis by an unstressed canopy and intercepted photosynthetically active radiation, which is then adjusted for stresses due to soil water shortage and temperature away from optimum. R has been calculated as the sum of growth and maintenance components (respectively, R g and R m. The R m has been determined from nitrogen content of plant tissue per unit ground area, while R g has been obtained as a fraction of the difference of A g and R m. Model parameters have not been determined by matching the calculated fluxes against observations at any location. Results are presented for cultivated and temperate deciduous forest areas over North America for five consecutive years (1986-1990) and compared with observations.

  5. How radiation influences atherosclerotic plaque development. A biophysical approach in ApoE{sup -/-} mice

    Energy Technology Data Exchange (ETDEWEB)

    Kloosterman, Astrid; Dillen, Teun van; Dekkers, Fieke [National Institute for Public Health and the Environment (RIVM), Centre for Environmental Safety and Security, Bilthoven (Netherlands); Bijwaard, Harmen [National Institute for Public Health and the Environment (RIVM), Centre for Environmental Safety and Security, Bilthoven (Netherlands); Inholland University of Applied Sciences, Medical Technology Research Group, Haarlem (Netherlands); Heeneman, Sylvia [Maastricht University Medical Center, Experimental Vascular Pathology group, Department of Pathology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht (Netherlands); Hoving, Saske; Stewart, Fiona A. [Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Division of Biological Stress Response (H3), Amsterdam (Netherlands)

    2017-11-15

    Atherosclerosis is the development of lipid-laden plaques in arteries and is nowadays considered as an inflammatory disease. It has been shown that high doses of ionizing radiation, as used in radiotherapy, can increase the risk of development or progression of atherosclerosis. To elucidate the effects of radiation on atherosclerosis, we propose a mathematical model to describe radiation-promoted plaque development. This model distinguishes itself from other models by combining plaque initiation and plaque growth, and by incorporating information from biological experiments. It is based on two consecutive processes: a probabilistic dose-dependent plaque initiation process, followed by deterministic plaque growth. As a proof of principle, experimental plaque size data from carotid arteries from irradiated ApoE{sup -/-} mice was used to illustrate how this model can provide insight into the underlying biological processes. This analysis supports the promoting role for radiation in plaque initiation, but the model can easily be extended to include dose-related effects on plaque growth if available experimental data would point in that direction. Moreover, the model could assist in designing future biological experiments on this research topic. Additional biological data such as plaque size data from chronically-irradiated mice or experimental data sets with a larger variety in biological parameters can help to further unravel the influence of radiation on plaque development. To the authors' knowledge, this is the first biophysical model that combines probabilistic and mechanistic modeling which uses experimental data to investigate the influence of radiation on plaque development. (orig.)

  6. Biophysical characterization of V3-lipopeptide liposomes influencing HIV-1 infectivity

    International Nuclear Information System (INIS)

    Rizos, Apostolos K.; Baritaki, Stavroula; Tsikalas, Ioannis; Doetschman, David C.; Spandidos, Demetrios A.; Krambovitis, Elias

    2007-01-01

    The V3-loop of the HIV-1 gp120 alters host cell immune function and modulates infectivity. We investigated biophysical parameters of liposome constructs with embedded lipopeptides from the principle neutralizing domain of the V3-loop and their influence on viral infectivity. Dynamic light scattering measurements showed liposome supramolecular structures with hydrodynamic radius of the order of 900 and 1300 nm for plain and V3-lipopeptide liposomes. Electron paramagnetic resonance measurements showed almost identical local microenvironment. The difference in liposome hydrodynamic radius was attributed to the fluctuating ionic environment of the V3-lipopeptide liposomes. In vitro HIV-1 infectivity assays showed that plain liposomes reduced virus production in all cell cultures, probably due to the hydrophobic nature of the aggregates. Liposomes carrying V3-lipopeptides with different cationic potentials restored and even enhanced infectivity (p < 0.05). These results highlight the need for elucidation of the involvement of lipid bilayers as dynamic components in supramolecular structures and in HIV-1 fusion mechanisms

  7. Graphene oxide as a protein matrix: influence on protein biophysical properties.

    Science.gov (United States)

    Hernández-Cancel, Griselle; Suazo-Dávila, Dámaris; Ojeda-Cruzado, Axel J; García-Torres, Desiree; Cabrera, Carlos R; Griebenow, Kai

    2015-10-19

    This study provides fundamental information on the influence of graphene oxide (GO) nanosheets and glycans on protein catalytic activity, dynamics, and thermal stability. We provide evidence of protein stabilization by glycans and how this strategy could be implemented when GO nanosheets is used as protein immobilization matrix. A series of bioconjugates was constructed using two different strategies: adsorbing or covalently attaching native and glycosylated bilirubin oxidase (BOD) to GO. Bioconjugate formation was followed by FT-IR, zeta-potential, and X-ray photoelectron spectroscopy measurements. Enzyme kinetic parameters (k(m) and k(cat)) revealed that the substrate binding affinity was not affected by glycosylation and immobilization on GO, but the rate of enzyme catalysis was reduced. Structural analysis by circular dichroism showed that glycosylation did not affect the tertiary or the secondary structure of BOD. However, GO produced slight changes in the secondary structure. To shed light into the biophysical consequence of protein glycosylation and protein immobilization on GO nanosheets, we studied structural protein dynamical changes by FT-IR H/D exchange and thermal inactivation. It was found that glycosylation caused a reduction in structural dynamics that resulted in an increase in thermostability and a decrease in the catalytic activity for both, glycoconjugate and immobilized enzyme. These results establish the usefulness of chemical glycosylation to modulate protein structural dynamics and stability to develop a more stable GO-protein matrix.

  8. FIACH: A biophysical model for automatic retrospective noise control in fMRI.

    Science.gov (United States)

    Tierney, Tim M; Weiss-Croft, Louise J; Centeno, Maria; Shamshiri, Elhum A; Perani, Suejen; Baldeweg, Torsten; Clark, Christopher A; Carmichael, David W

    2016-01-01

    Different noise sources in fMRI acquisition can lead to spurious false positives and reduced sensitivity. We have developed a biophysically-based model (named FIACH: Functional Image Artefact Correction Heuristic) which extends current retrospective noise control methods in fMRI. FIACH can be applied to both General Linear Model (GLM) and resting state functional connectivity MRI (rs-fcMRI) studies. FIACH is a two-step procedure involving the identification and correction of non-physiological large amplitude temporal signal changes and spatial regions of high temporal instability. We have demonstrated its efficacy in a sample of 42 healthy children while performing language tasks that include overt speech with known activations. We demonstrate large improvements in sensitivity when FIACH is compared with current methods of retrospective correction. FIACH reduces the confounding effects of noise and increases the study's power by explaining significant variance that is not contained within the commonly used motion parameters. The method is particularly useful in detecting activations in inferior temporal regions which have proven problematic for fMRI. We have shown greater reproducibility and robustness of fMRI responses using FIACH in the context of task induced motion. In a clinical setting this will translate to increasing the reliability and sensitivity of fMRI used for the identification of language lateralisation and eloquent cortex. FIACH can benefit studies of cognitive development in young children, patient populations and older adults. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  9. Statistical and Biophysical Models for Predicting Total and Outdoor Water Use in Los Angeles

    Science.gov (United States)

    Mini, C.; Hogue, T. S.; Pincetl, S.

    2012-04-01

    Modeling water demand is a complex exercise in the choice of the functional form, techniques and variables to integrate in the model. The goal of the current research is to identify the determinants that control total and outdoor residential water use in semi-arid cities and to utilize that information in the development of statistical and biophysical models that can forecast spatial and temporal urban water use. The City of Los Angeles is unique in its highly diverse socio-demographic, economic and cultural characteristics across neighborhoods, which introduces significant challenges in modeling water use. Increasing climate variability also contributes to uncertainties in water use predictions in urban areas. Monthly individual water use records were acquired from the Los Angeles Department of Water and Power (LADWP) for the 2000 to 2010 period. Study predictors of residential water use include socio-demographic, economic, climate and landscaping variables at the zip code level collected from US Census database. Climate variables are estimated from ground-based observations and calculated at the centroid of each zip code by inverse-distance weighting method. Remotely-sensed products of vegetation biomass and landscape land cover are also utilized. Two linear regression models were developed based on the panel data and variables described: a pooled-OLS regression model and a linear mixed effects model. Both models show income per capita and the percentage of landscape areas in each zip code as being statistically significant predictors. The pooled-OLS model tends to over-estimate higher water use zip codes and both models provide similar RMSE values.Outdoor water use was estimated at the census tract level as the residual between total water use and indoor use. This residual is being compared with the output from a biophysical model including tree and grass cover areas, climate variables and estimates of evapotranspiration at very high spatial resolution. A

  10. Novel biophysical determination of miRNAs related to prostate and head and neck cancers

    Czech Academy of Sciences Publication Activity Database

    Hudcová, K.; Trnková, L.; Kejnovská, Iva; Vorlíčková, Michaela; Gumulec, J.; Kizek, R.; Masarik, M.

    2015-01-01

    Roč. 44, č. 3 (2015), s. 131-138 ISSN 0175-7571 Institutional support: RVO:68081707 Keywords : SQUAMOUS-CELL CARCINOMA * ELIMINATION VOLTAMMETRY * CYTOSINE SIGNALS Subject RIV: BO - Biophysics Impact factor: 1.444, year: 2015

  11. LBA-ECO ND-01 Reflectance and Biophysical Measures, Grass Pastures: Rondonia, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set provides the results of spectral reflectance (350 to 2,500 nm at 1-nm increments) and biophysical measurements on grass pastures in eight...

  12. Biophysical properties of membrane lipids of anammox bacteria : I. Ladderane phospholipids form highly organized fluid membranes

    NARCIS (Netherlands)

    Boumann, Henry A.; Longo, Marjorie L.; Stroeve, Pieter; Poolman, Bert; Hopmans, Ellen C.; Stuart, Marc C. A.; Damste, Jaap S. Sinninghe; Schouten, Stefan

    Anammox bacteria that are capable of anaerobically oxidizing ammonium (anammox) with nitrite to nitrogen gas produce unique membrane phospholipids that comprise hydrocarbon chains with three or five linearly condensed cyclobutane rings. To gain insight into the biophysical properties of these

  13. Elucidating the molecular mechanisms underlying cellular response to biophysical cues using synthetic biology approaches

    NARCIS (Netherlands)

    Denning, Denise; Roos, Wouter H

    2016-01-01

    The use of synthetic surfaces and materials to influence and study cell behavior has vastly progressed our understanding of the underlying molecular mechanisms involved in cellular response to physicochemical and biophysical cues. Reconstituting cytoskeletal proteins and interfacing them with a

  14. A Method Sustaining the Bioelectric, Biophysical, and Bioenergetic Function of Cultured Rabbit Atrial Cells

    OpenAIRE

    Noa Kirschner Peretz; Sofia Segal; Limor Arbel-Ganon; Ronen Ben Jehuda; Ronen Ben Jehuda; Yuval Shemer; Yuval Shemer; Binyamin Eisen; Binyamin Eisen; Moran Davoodi; Ofer Binah; Ofer Binah; Yael Yaniv

    2017-01-01

    Culturing atrial cells leads to a loss in their ability to be externally paced at physiological rates and to maintain their shape. We aim to develop a culture method that sustains the shape of atrial cells along with their biophysical and bioenergetic properties in response to physiological pacing. We hypothesize that adding 2,3-Butanedione 2-monoxime (BDM), which inhibits contraction during the culture period, will preserve these biophysical and bioenergetic properties. Rabbit atrial cells w...

  15. Cellular normoxic biophysical markers of hydroxyurea treatment in sickle cell disease

    OpenAIRE

    Hosseini, Poorya; Abidi, Sabia Z.; Du, E; Papageorgiou, Dimitrios P.; Choi, Youngwoon; Park, YongKeun; Higgins, John M.; Kato, Gregory J.; Suresh, Subra; Dao, Ming; Yaqoob, Zahid; So, Peter T. C.

    2016-01-01

    There exists a critical need for developing biomarkers reflecting clinical outcomes and for evaluating the effectiveness of treatments for sickle cell disease patients. Prior attempts to find such patient-specific markers have mostly relied upon chemical biomarkers or biophysical properties at hypoxia with limited success. We introduce unique biomarkers based on characterization of cellular biophysical properties at normoxia and show that these markers correlate sensitively with treatment usi...

  16. Sonographic biophysical profile in detection of foetal hypoxia in 100 cases of suspected high risk pregnancy

    International Nuclear Information System (INIS)

    Ullah, N.; Khan, A.R.; Usman, M.

    2010-01-01

    Background: The foetus has become increasingly accessible and visible as a patient over the last two decades. Ultrasound imaging has broadened the scope of foetal assessment. Dynamic real time B-Mode ultrasound is used to monitor cluster of biophysical variables, both dynamic and static collectively termed as biophysical profile. The purpose of this study was to determine the effect of sonographic biophysical profile score on perinatal outcome in terms of mortality and morbidity. Methods: This descriptive study was carried on 100 randomly select ed high risk pregnant patients in Radiology Department PGMI, Government Lady Reading Hospital, Peshawar from December 2007 to June 2008. Manning biophysical profile including non-stress was employed for foetal screening, using Toshiba ultrasound machine model Nemio SSA-550A and 7.5 MHZ probe. Results: Out of 100 cases 79 (79%) had a normal biophysical profile in the last scan of 10/10 and had a normal perinatal outcome with 5 minutes Apgar score >7/10. In 13 (13%) cases Apgar score at 5 minute was < 7/10 and babies were shifted to nursery. There were 2 (2%) false positive cases that showed abnormal biophysical profile scores of 6/10 but babies were born with an Apgar score of 8/10 at 5 minutes. There were 2 (2%) neonatal deaths in this study group. The sensitivity of biophysical profile was 79.1%, specificity 92.9%. Predictive value for a positive test was 98.55%; predictive value for a negative test was 41.93%. Conclusion: Biophysical profile is highly accurate and reliable test of diagnosing foetal hypoxia. (author)

  17. Parameter Estimation

    DEFF Research Database (Denmark)

    Sales-Cruz, Mauricio; Heitzig, Martina; Cameron, Ian

    2011-01-01

    of optimisation techniques coupled with dynamic solution of the underlying model. Linear and nonlinear approaches to parameter estimation are investigated. There is also the application of maximum likelihood principles in the estimation of parameters, as well as the use of orthogonal collocation to generate a set......In this chapter the importance of parameter estimation in model development is illustrated through various applications related to reaction systems. In particular, rate constants in a reaction system are obtained through parameter estimation methods. These approaches often require the application...... of algebraic equations as the basis for parameter estimation.These approaches are illustrated using estimations of kinetic constants from reaction system models....

  18. Characterization of oily mature skin by biophysical and skin imaging techniques.

    Science.gov (United States)

    de Melo, M O; Maia Campos, P M B G

    2018-02-13

    The skin is a complex biological system and may suffer change according to the environmental factors, as higher temperatures can increase sebum excretion, presenting oiliness and acne. These alterations can persist during the aging and provoke more changes in aged skin. In this study we evaluated the mature oily skin characteristics using biophysical and skin imaging techniques. Sixty healthy female subjects, aged between 39 and 55 years old were recruited and separated into 2 groups according to their skin type: normal/dry and oily skin. The skin was evaluated in terms of stratum corneum water content, transepidermal water loss (TEWL) sebum content, dermis thickness and echogenicity, skin microrelief, and pores content. The mature oily skin presented no significant differences when compared to the normal/dry skin on the stratum corneum water content and TEWL parameters. The sebum content was significantly higher on the oily skin group. The microrelief analysis showed an increase of skin roughness values in the oily skin and increase of scaliness in the normal/dry skin. The oily skin showed lower dermis echogenicity mainly in the frontal region and higher dermis thickness when compared to normal/dry skin. The mature oily skin showed different characteristics from normal/dry skin in terms of sebum content, microrelief parameters, and dermis thickness. This way, the characterization of mature oily skin in an objective way is very important to development of dermocosmetic products for more effective treatments focused specially on this type of skin. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. REMOTE-SENSING-BASED BIOPHYSICAL MODELS FOR ESTIMATING LAI OF IRRIGATED CROPS IN MURRY DARLING BASIN

    Directory of Open Access Journals (Sweden)

    I. Wittamperuma

    2012-07-01

    Full Text Available Remote sensing is a rapid and reliable method for estimating crop growth data from individual plant to crops in irrigated agriculture ecosystem. The LAI is one of the important biophysical parameter for determining vegetation health, biomass, photosynthesis and evapotranspiration (ET for the modelling of crop yield and water productivity. Ground measurement of this parameter is tedious and time-consuming due to heterogeneity across the landscape over time and space. This study deals with the development of remote-sensing based empirical relationships for the estimation of ground-based LAI (LAIG using NDVI, modelled with and without atmospheric correction models for three irrigated crops (corn, wheat and rice grown in irrigated farms within Coleambally Irrigation Area (CIA which is located in southern Murray Darling basin, NSW in Australia. Extensive ground truthing campaigns were carried out to measure crop growth and to collect field samples of LAI using LAI- 2000 Plant Canopy Analyser and reflectance using CROPSCAN Multi Spectral Radiometer at several farms within the CIA. A Set of 12 cloud free Landsat 5 TM satellite images for the period of 2010-11 were downloaded and regression analysis was carried out to analyse the co-relationships between satellite and ground measured reflectance and to check the reliability of data sets for the crops. Among all the developed regression relationships between LAI and NDVI, the atmospheric correction process has significantly improved the relationship between LAI and NDVI for Landsat 5 TM images. The regression analysis also shows strong correlations for corn and wheat but weak correlations for rice which is currently being investigated.

  20. Time-resolved biophysical approaches to nucleocytoplasmic transport

    Directory of Open Access Journals (Sweden)

    Francesco Cardarelli

    Full Text Available Molecules are continuously shuttling across the nuclear envelope barrier that separates the nucleus from the cytoplasm. Instead of being just a barrier to diffusion, the nuclear envelope is rather a complex filter that provides eukaryotes with an elaborate spatiotemporal regulation of fundamental molecular processes, such as gene expression and protein translation. Given the highly dynamic nature of nucleocytoplasmic transport, during the past few decades large efforts were devoted to the development and application of time resolved, fluorescence-based, biophysical methods to capture the details of molecular motion across the nuclear envelope. These methods are here divided into three major classes, according to the differences in the way they report on the molecular process of nucleocytoplasmic transport. In detail, the first class encompasses those methods based on the perturbation of the fluorescence signal, also known as ensemble-averaging methods, which average the behavior of many molecules (across many pores. The second class comprises those methods based on the localization of single fluorescently-labelled molecules and tracking of their position in space and time, potentially across single pores. Finally, the third class encompasses methods based on the statistical analysis of spontaneous fluorescence fluctuations out of the equilibrium or stationary state of the system. In this case, the behavior of single molecules is probed in presence of many similarly-labelled molecules, without dwelling on any of them. Here these three classes, with their respective pros and cons as well as their main applications to nucleocytoplasmic shuttling will be briefly reviewed and discussed. Keywords: Fluorescence recovery after photobleaching, Single particle tracking, Fluorescence correlation spectroscopy, Diffusion, Transport, GFP, Nuclear pore complex, Live cell, Confocal microscopy

  1. Gradient Models in Molecular Biophysics: Progress, Challenges, Opportunities.

    Science.gov (United States)

    Bardhan, Jaydeep P

    2013-12-01

    In the interest of developing a bridge between researchers modeling materials and those modeling biological molecules, we survey recent progress in developing nonlocal-dielectric continuum models for studying the behavior of proteins and nucleic acids. As in other areas of science, continuum models are essential tools when atomistic simulations (e.g. molecular dynamics) are too expensive. Because biological molecules are essentially all nanoscale systems, the standard continuum model, involving local dielectric response, has basically always been dubious at best. The advanced continuum theories discussed here aim to remedy these shortcomings by adding features such as nonlocal dielectric response, and nonlinearities resulting from dielectric saturation. We begin by describing the central role of electrostatic interactions in biology at the molecular scale, and motivate the development of computationally tractable continuum models using applications in science and engineering. For context, we highlight some of the most important challenges that remain and survey the diverse theoretical formalisms for their treatment, highlighting the rigorous statistical mechanics that support the use and improvement of continuum models. We then address the development and implementation of nonlocal dielectric models, an approach pioneered by Dogonadze, Kornyshev, and their collaborators almost forty years ago. The simplest of these models is just a scalar form of gradient elasticity, and here we use ideas from gradient-based modeling to extend the electrostatic model to include additional length scales. The paper concludes with a discussion of open questions for model development, highlighting the many opportunities for the materials community to leverage its physical, mathematical, and computational expertise to help solve one of the most challenging questions in molecular biology and biophysics.

  2. Biophysics of malarial parasite exit from infected erythrocytes.

    Science.gov (United States)

    Chandramohanadas, Rajesh; Park, YongKeun; Lui, Lena; Li, Ang; Quinn, David; Liew, Kingsley; Diez-Silva, Monica; Sung, Yongjin; Dao, Ming; Lim, Chwee Teck; Preiser, Peter Rainer; Suresh, Subra

    2011-01-01

    Upon infection and development within human erythrocytes, P. falciparum induces alterations to the infected RBC morphology and bio-mechanical properties to eventually rupture the host cells through parasitic and host derived proteases of cysteine and serine families. We used previously reported broad-spectrum inhibitors (E64d, EGTA-AM and chymostatin) to inhibit these proteases and impede rupture to analyze mechanical signatures associated with parasite escape. Treatment of late-stage iRBCs with E64d and EGTA-AM prevented rupture, resulted in no major RBC cytoskeletal reconfiguration but altered schizont morphology followed by dramatic re-distribution of three-dimensional refractive index (3D-RI) within the iRBC. These phenotypes demonstrated several-fold increased iRBC membrane flickering. In contrast, chymostatin treatment showed no 3D-RI changes and caused elevated fluctuations solely within the parasitophorous vacuole. We show that E64d and EGTA-AM supported PV breakdown and the resulting elevated fluctuations followed non-Gaussian pattern that resulted from direct merozoite impingement against the iRBC membrane. Optical trapping experiments highlighted reduced deformability of the iRBC membranes upon rupture-arrest, more specifically in the treatments that facilitated PV breakdown. Taken together, our experiments provide novel mechanistic interpretations on the role of parasitophorous vacuole in maintaining the spherical schizont morphology, the impact of PV breakdown on iRBC membrane fluctuations leading to eventual parasite escape and the evolution of membrane stiffness properties of host cells in which merozoites were irreversibly trapped, recourse to protease inhibitors. These findings provide a comprehensive, previously unavailable, body of information on the combined effects of biochemical and biophysical factors on parasite egress from iRBCs.

  3. Gradient Models in Molecular Biophysics: Progress, Challenges, Opportunities

    Science.gov (United States)

    Bardhan, Jaydeep P.

    2014-01-01

    In the interest of developing a bridge between researchers modeling materials and those modeling biological molecules, we survey recent progress in developing nonlocal-dielectric continuum models for studying the behavior of proteins and nucleic acids. As in other areas of science, continuum models are essential tools when atomistic simulations (e.g. molecular dynamics) are too expensive. Because biological molecules are essentially all nanoscale systems, the standard continuum model, involving local dielectric response, has basically always been dubious at best. The advanced continuum theories discussed here aim to remedy these shortcomings by adding features such as nonlocal dielectric response, and nonlinearities resulting from dielectric saturation. We begin by describing the central role of electrostatic interactions in biology at the molecular scale, and motivate the development of computationally tractable continuum models using applications in science and engineering. For context, we highlight some of the most important challenges that remain and survey the diverse theoretical formalisms for their treatment, highlighting the rigorous statistical mechanics that support the use and improvement of continuum models. We then address the development and implementation of nonlocal dielectric models, an approach pioneered by Dogonadze, Kornyshev, and their collaborators almost forty years ago. The simplest of these models is just a scalar form of gradient elasticity, and here we use ideas from gradient-based modeling to extend the electrostatic model to include additional length scales. The paper concludes with a discussion of open questions for model development, highlighting the many opportunities for the materials community to leverage its physical, mathematical, and computational expertise to help solve one of the most challenging questions in molecular biology and biophysics. PMID:25505358

  4. Gradient models in molecular biophysics: progress, challenges, opportunities

    Science.gov (United States)

    Bardhan, Jaydeep P.

    2013-12-01

    In the interest of developing a bridge between researchers modeling materials and those modeling biological molecules, we survey recent progress in developing nonlocal-dielectric continuum models for studying the behavior of proteins and nucleic acids. As in other areas of science, continuum models are essential tools when atomistic simulations (e.g., molecular dynamics) are too expensive. Because biological molecules are essentially all nanoscale systems, the standard continuum model, involving local dielectric response, has basically always been dubious at best. The advanced continuum theories discussed here aim to remedy these shortcomings by adding nonlocal dielectric response. We begin by describing the central role of electrostatic interactions in biology at the molecular scale, and motivate the development of computationally tractable continuum models using applications in science and engineering. For context, we highlight some of the most important challenges that remain, and survey the diverse theoretical formalisms for their treatment, highlighting the rigorous statistical mechanics that support the use and improvement of continuum models. We then address the development and implementation of nonlocal dielectric models, an approach pioneered by Dogonadze, Kornyshev, and their collaborators almost 40 years ago. The simplest of these models is just a scalar form of gradient elasticity, and here we use ideas from gradient-based modeling to extend the electrostatic model to include additional length scales. The review concludes with a discussion of open questions for model development, highlighting the many opportunities for the materials community to leverage its physical, mathematical, and computational expertise to help solve one of the most challenging questions in molecular biology and biophysics.

  5. Electron paramagnetic resonance biophysical radiation dosimetry with tooth enamel

    International Nuclear Information System (INIS)

    Khan, Rao F.H.

    2003-01-01

    This thesis deals with the advancements made in the field of Electron Paramagnetic Resonance (EPR) for biophysical dosimetry with tooth enamel for accident, emergency, and retrospective radiation dose reconstruction. A methodology has been developed to measure retrospective radiation exposures in human tooth enamel. This entails novel sample preparation procedures with minimum mechanical treatment to reduce the preparation induced uncertainties, establish optimum measurement conditions inside the EPR cavity, post-process the measured spectrum with functional simulation of dosimetric and other interfering signals, and reconstruct dose. By using this technique, retrospective gamma exposures as low as 80±30 mGy have been successfully deciphered. The notion of dose modifier was introduced in EPR biodosimetry for low dose measurements. It has been demonstrated that by using the modified zero added dose (MZAD) technique for low radiation exposures, doses in 100 mGy ranges can be easily reconstructed in teeth that were previously thought useless for EPR dosimetry. Also, the use of a dose modifier makes robust dose reconstruction possible for higher radiation exposures. The EPR dosimetry technique was also developed for tooth samples extracted from rodents, which represent small tooth sizing. EPR doses in the molars, extracted from the mice irradiated with whole body exposures, were reassessed and shown to be correct within the experimental uncertainty. The sensitivity of human tooth enamel for neutron irradiation, obtained from the 3 MV McMaster K.N. Van de Graaff accelerator, was also studied. For the first time this work has shown that the neutron sensitivity of the tooth enamel is approximately 1/10th of the equivalent gamma sensitivity. Parametric studies for neutron dose rate and neutron energy within the available range of the accelerator, showed no impact on the sensitivity of the tooth enamel. Therefore, tooth enamel can be used as a dosimeter for both neutrons

  6. Biophysical impacts of climate-smart agriculture in the Midwest United States.

    Science.gov (United States)

    Bagley, Justin E; Miller, Jesse; Bernacchi, Carl J

    2015-09-01

    The potential impacts of climate change in the Midwest United States present unprecedented challenges to regional agriculture. In response to these challenges, a variety of climate-smart agricultural methodologies have been proposed to retain or improve crop yields, reduce agricultural greenhouse gas emissions, retain soil quality and increase climate resilience of agricultural systems. One component that is commonly neglected when assessing the environmental impacts of climate-smart agriculture is the biophysical impacts, where changes in ecosystem fluxes and storage of moisture and energy lead to perturbations in local climate and water availability. Using a combination of observational data and an agroecosystem model, a series of climate-smart agricultural scenarios were assessed to determine the biophysical impacts these techniques have in the Midwest United States. The first scenario extended the growing season for existing crops using future temperature and CO2 concentrations. The second scenario examined the biophysical impacts of no-till agriculture and the impacts of annually retaining crop debris. Finally, the third scenario evaluated the potential impacts that the adoption of perennial cultivars had on biophysical quantities. Each of these scenarios was found to have significant biophysical impacts. However, the timing and magnitude of the biophysical impacts differed between scenarios. © 2014 John Wiley & Sons Ltd.

  7. Biophysical landscape interactions: Bridging disciplines and scale with connectivity

    Science.gov (United States)

    van der Ploeg, Martine; Baartman, Jantiene; Robinson, David

    2017-04-01

    The combination of climate change, population growth and soil threats, such as carbon loss, biodiversity decline or erosion amongst others , increasingly confront the global community [1]. One of the major challenges in studying processes involved in soil threats, landscape resilience, ecosystem stability, sustainable land management and the economic consequences, is that it is an interdisciplinary field [2], that needs less stringent scientific disciplinary boundaries [3]. As a result of disciplinary focus, ambiguity may arise on the understanding of landscape interactions, and this is especially true in the interaction between a landscape's physical and biological processes [4]. Another important aspect in biophysical landscape interactions are the differences in scale related to the various processes that play a role in these systems. While scaling of environmental processes is possible, as long as the phenomena at hand can be described by the same set of differential equations [5], biophysical landscape interactions pose problems for scaling approaches. Landscape position and land use impact the coupled processes in soil and vegetation. Differences in micro-behavior, driven by the interplay of heterogeneous soil and vegetation dynamics, impact emergent characteristics across a landscape. A complicating factor is the response of vegetation to changing environmental conditions, including a possible and often unknown time-lag. By altering soil conditions, plants may leave an imprint in the landscape that remains even after vegetation has disappeared due to e.g. drought, wildfire or overgrazing. Plants also respond biochemically to their environment, while the models used for hydrology are often based on physical interactions. Gene-expression and genotype adaptation may further complicate our modelling efforts in for example climate change impacts. What are we missing by not having more connectivity in our thinking, and what we can solve? We think that integrated

  8. The value of mechanistic biophysical information for systems-level understanding of complex biological processes such as cytokinesis.

    Science.gov (United States)

    Pollard, Thomas D

    2014-12-02

    This review illustrates the value of quantitative information including concentrations, kinetic constants and equilibrium constants in modeling and simulating complex biological processes. Although much has been learned about some biological systems without these parameter values, they greatly strengthen mechanistic accounts of dynamical systems. The analysis of muscle contraction is a classic example of the value of combining an inventory of the molecules, atomic structures of the molecules, kinetic constants for the reactions, reconstitutions with purified proteins and theoretical modeling to account for the contraction of whole muscles. A similar strategy is now being used to understand the mechanism of cytokinesis using fission yeast as a favorable model system. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  9. Restaurants closed over Christmas

    CERN Multimedia

    2011-01-01

    The restaurants will be closed during the Christmas holiday period : please note that all three CERN Restaurants will be closed from 5 p.m. on Wednesday, 21 December until Wednesday, 4 January inclusive. The Restaurants will reopen on Thursday, 5 January 2012.

  10. The Multistream Self: Biophysical, Mental, Social, and Existential

    Directory of Open Access Journals (Sweden)

    Vinod D. Deshmukh

    2008-01-01

    Full Text Available Self is difficult to define because of its multiple, constitutive streams of functional existence. A more comprehensive and expanded definition of self is proposed. The standard bio-psycho-social model of psyche is expanded to biophysical-mental-social and existential self. The total human experience is better understood and explained by adding the existential component. Existential refers to lived human experience, which is firmly rooted in reality. Existential living is the capacity to live fully in the present, and respond freely and flexibly to new experience without fear. Four common fears of isolation, insecurity, insignificance, and death can be overcome by developing a lifestyle of whole-hearted engagement in the present reality, creative problem solving, self-actualization, and altruism. Such integrative living creates a sense of presence with self-awareness, understanding, and existential well-being. Well-being is defined as a life of happiness, contentment, low distress, and good health with positive outlook. Self is a complex, integrative process of living organisms. It organizes, coordinates, and integrates energy-information within and around itself, spontaneously, unconsciously, and consciously. Self-process is understood in terms of synergetics, coordination dynamics, and energy-information–directed self-organization. It is dynamic, composite, ever renewing, and enduring. It can be convergent or divergent, and can function as the source or target of its own behavior-mentation. The experience of self is continuously generated by spontaneous activation of neural networks in the cerebral neocortex by the brainstem-diencephalic arousal system. The multiple constitutive behavioral-mental streams develop concurrently into a unique experience of self, specific for a person at his/her developmental stage. The chronological neuro-behavioral-mental development of self is described in detail from embryonic stage to old age. Self can be

  11. Daytime Changes of Skin Biophysical Characteristics: A Study of Hydration, Transepidermal Water Loss, pH, Sebum, Elasticity, Erythema, and Color Index on Middle Eastern Skin.

    Science.gov (United States)

    Firooz, Alireza; Zartab, Hamed; Sadr, Bardia; Bagherpour, Leili Naraghi; Masoudi, Aidin; Fanian, Ferial; Dowlati, Yahya; Ehsani, Amir Hooshang; Samadi, Aniseh

    2016-01-01

    The exposure of skin to ultraviolet radiation and temperature differs significantly during the day. It is reasonable that biophysical parameters of human skin have periodic daily fluctuation. The objective of this study was to study the fluctuations of various biophysical characteristics of Middle Eastern skin in standardized experimental conditions. Seven biophysical parameters of skin including stratum corneum hydration, transepidermal water loss, pH, sebum, elasticity, skin color, and erythema index were measured at three time points (8 a.m., 12 p.m. and 4 p.m.) on the forearm of 12 healthy participants (mean age of 28.4 years) without any ongoing skin disease using the CK MPA 580 device in standard temperature and humidity conditions. A significant difference was observed between means of skin color index at 8 a.m. (175.42 ± 13.92) and 4 p.m. (164.44 ± 13.72, P = 0.025), between the pH at 8 a.m. (5.72 ± 0.48) and 4 p.m. (5.33 ± 0.55, P = 0.001) and pH at 12 p.m. (5.60 ± 0.48) and 4 p.m. (5.33 ± 0.55, P = 0.001). Other comparisons between the means of these parameters at different time points resulted in nonsignificant P values. There are daytime changes in skin color index and pH. Skin color index might be higher and cutaneous pH more basic in the early morning compared to later of the day.

  12. Daytime changes of skin biophysical characteristics: A study of hydration, transepidermal water loss, ph, sebum, elasticity, erythema, and color index on middle eastern skin

    Directory of Open Access Journals (Sweden)

    Alireza Firooz

    2016-01-01

    Full Text Available Background: The exposure of skin to ultraviolet radiation and temperature differs significantly during the day. It is reasonable that biophysical parameters of human skin have periodic daily fluctuation. The objective of this study was to study the fluctuations of various biophysical characteristics of Middle Eastern skin in standardized experimental conditions. Materials and Methods: Seven biophysical parameters of skin including stratum corneum hydration, transepidermal water loss, pH, sebum, elasticity, skin color, and erythema index were measured at three time points (8 a.m., 12 p.m. and 4 p.m. on the forearm of 12 healthy participants (mean age of 28.4 years without any ongoing skin disease using the CK MPA 580 device in standard temperature and humidity conditions. Results: A significant difference was observed between means of skin color index at 8 a.m. (175.42 ± 13.92 and 4 p.m. (164.44 ± 13.72, P = 0.025, between the pH at 8 a.m. (5.72 ± 0.48 and 4 p.m. (5.33 ± 0.55, P = 0.001 and pH at 12 p.m. (5.60 ± 0.48 and 4 p.m. (5.33 ± 0.55, P = 0.001. Other comparisons between the means of these parameters at different time points resulted in nonsignificant P values. Conclusion: There are daytime changes in skin color index and pH. Skin color index might be higher and cutaneous pH more basic in the early morning compared to later of the day.

  13. Replacing natural wetlands with stormwater management facilities: Biophysical and perceived social values.

    Science.gov (United States)

    Rooney, R C; Foote, L; Krogman, N; Pattison, J K; Wilson, M J; Bayley, S E

    2015-04-15

    Urban expansion replaces wetlands of natural origin with artificial stormwater management facilities. The literature suggests that efforts to mimic natural wetlands in the design of stormwater facilities can expand the provision of ecosystem services. Policy developments seek to capitalize on these improvements, encouraging developers to build stormwater wetlands in place of stormwater ponds; however, few have compared the biophysical values and social perceptions of these created wetlands to those of the natural wetlands they are replacing. We compared four types of wetlands: natural references sites, natural wetlands impacted by agriculture, created stormwater wetlands, and created stormwater ponds. We anticipated that they would exhibit a gradient in biodiversity, ecological integrity, chemical and hydrologic stress. We further anticipated that perceived values would mirror measured biophysical values. We found higher biophysical values associated with wetlands of natural origin (both reference and agriculturally impacted). The biophysical values of stormwater wetlands and stormwater ponds were lower and indistinguishable from one another. The perceived wetland values assessed by the public differed from the observed biophysical values. This has important policy implications, as the public are not likely to perceive the loss of values associated with the replacement of natural wetlands with created stormwater management facilities. We conclude that 1) agriculturally impacted wetlands provide biophysical values equivalent to those of natural wetlands, meaning that land use alone is not a great predictor of wetland value; 2) stormwater wetlands are not a substantive improvement over stormwater ponds, relative to wetlands of natural origin; 3) stormwater wetlands are poor mimics of natural wetlands, likely due to fundamental distinctions in terms of basin morphology, temporal variation in hydrology, ground water connectivity, and landscape position; 4) these

  14. Closed string field theory

    International Nuclear Information System (INIS)

    Strominger, A.

    1987-01-01

    A gauge invariant cubic action describing bosonic closed string field theory is constructed. The gauge symmetries include local spacetime diffeomorphisms. The conventional closed string spectrum and trilinear couplings are reproduced after spontaneous symmetry breaking. The action S is constructed from the usual ''open string'' field of ghost number minus one half. It is given by the associator of the string field product which is non-vanishing because of associativity anomalies. S does not describe open string propagation because open string states associate and can thereby be shifted away. A field theory of closed and open strings can be obtained by adding to S the cubic open string action. (orig.)

  15. Pipe closing device

    International Nuclear Information System (INIS)

    Klahn, F.C.; Nolan, J.H.; Wills, C.

    1979-01-01

    The closing device closes the upper end of a support tube for monitoring samples. It meshes with the upper connecting piece of the monitorung sample capsule, and loads the capsule within the bore of the support tube, so that it is fixed but can be released. The closing device consists of an interlocking component with a chamber and several ratchets which hang down. The interlocking component surrounds the actuating component for positioning the ratchets. The interlocking and actuating components are movable axially relative to each other. (DG) [de

  16. Comparison of biophysical factors influencing on emphysema quantification with low-dose CT

    Science.gov (United States)

    Heo, Chang Yong; Kim, Jong Hyo

    2014-03-01

    Emphysema Index(EI) measurements in MDCT is known to be influenced by various biophysical factors such as total lung volume, and body size. We investigated the association of the four biophysical factors with emphysema index in low-dose MDCT. In particular, we attempted to identify a potentially stronger biophysical factor than total lung volume. A total of 400 low-dose MDCT volumes taken at 120kVp, 40mAs, 1mm thickness, and B30f reconstruction kernel were used. The lungs, airways, and pulmonary vessels were automatically segmented, and two Emphysema Indices, relative area below -950HU(RA950) and 15th percentile(Perc15), were extracted from the segmented lungs. The biophysical factors such as total lung volume(TLV), mode of lung attenuation(ModLA), effective body diameter(EBD), and the water equivalent body diameter(WBD) were estimated from the segmented lung and body area. The association of biophysical factors with emphysema indices were evaluated by correlation coefficients. The mean emphysema indices were 8.3±5.5(%) in RA950, and -930±18(HU) in Perc15. The estimates of biophysical factors were 4.7±1.0(L) in TLV, -901±21(HU) in ModLA, 26.9±2.2(cm) in EBD, and 25.9±2.6(cm) in WBD. The correlation coefficients of biophysical factors with RA950 were 0.73 in TLV, 0.94 in ModLA, 0.31 in EBD, and 0.18 WBD, the ones with Perc15 were 0.74 in TLV, 0.98 in ModLA, 0.29 in EBD, and 0.15 WBD. Study results revealed that two biophysical factors, TLV and ModLA, mostly affects the emphysema indices. In particular, the ModLA exhibited strongest correlation of 0.98 with Perc15, which indicating the ModLA is the most significant confounding biophysical factor in emphysema indices measurement.

  17. The biophysical properties of the aorta are altered following Kawasaki disease.

    Science.gov (United States)

    Vaujois, Laurence; Dallaire, Frédéric; Maurice, Roch L; Fournier, Anne; Houde, Christine; Thérien, Johanne; Cartwright, Daniel; Dahdah, Nagib

    2013-12-01

    The long-term sequelae of Kawasaki disease (KD) are based on the coronary complications. Because KD causes generalized vasculitis, with documented aneurysms in the femoral, iliac, renal, axillary, and brachial arteries, the aim of this study was to assess the biophysical properties of the aorta (BPA) after KD. The BPA are biometric measurements representing vascular structural and dynamic changes in response to cardiac work. Anthropometric and echocardiographic measurements of the aorta in a series of patients with KD were compared with those of healthy subjects. The BPA were calculated noninvasively by extrapolating previously validated equations that were conceived for invasive measurements. Because BPA vary with body habitus, control subjects were used to normalize BPA parameters for height to compute BPA Z-score equations. Between June 2007 and February 2010, BPA were recorded in 57 patients with KD >1 year after the onset of the disease, 45 without and 12 with coronary artery sequelae. The mean intervals between the acute onset of KD and enrollment were 10.0 ± 5.0 and 5.8 ± 4.5 years for patients with and without coronary artery sequelae, respectively (P = .008). Patients with KD with coronary artery sequelae had significantly altered Z scores of aortic diameter modulation, Peterson's elastic modulus, and β stiffness index (P = .001-.016). Patients with KD without coronary artery sequelae also exhibited altered elasticity, stiffness, and pulse-wave velocity (P = .001-.026). Altered BPA after KD are detectible despite apparent resolution of acute vasculitis. Future directions toward determining multilevel and multilayer vascular impact, including vascular autonomous homeostasis, require thorough investigation. Copyright © 2013 American Society of Echocardiography. Published by Mosby, Inc. All rights reserved.

  18. Biophysical processes leading to the ingress of temperate fish larvae into estuarine nursery areas: A review

    Science.gov (United States)

    Teodósio, Maria Alexandra; Paris, Claire B.; Wolanski, Eric; Morais, Pedro

    2016-12-01

    A series of complementary hypotheses have been proposed to explain the recruitment of marine and temperate pelagic fish larvae originated from pelagic eggs in coastal environments. In this review, we propose a new and complementary hypothesis describing the biophysical processes intervening in the recruitment of temperate fish larvae into estuaries. This new hypothesis, the Sense Acuity And Behavioral (SAAB) hypothesis, recognizes that recruitment is unlikely if the larvae drift passively with the water currents, and that successful recruitment requires the sense acuity of temperate fish larvae and their behavioral response to the estuarine cues present in coastal areas. We propose that temperate fish larvae use a hierarchy of sensory cues (odor, sound, visual and geomagnetic cues) to detect estuarine nursery areas and to aid during navigation towards these areas. The sensorial acuity increases along ontogeny, which coincides with increased swimming capabilities. The swimming strategies of post-flexion larvae differ from offshore areas to the tidal zone. In offshore areas, innate behavior might lead larvae towards the coast guided by a sun compass or by the earth's geomagnetic field. In areas under limited influence of estuarine plumes (either in energetic nearshore areas or offshore), post-flexion larvae display a searching swimming behavior for estuarine disconnected patches (infotaxis strategy). After finding an estuarine plume, larvae may swim along the increasing cue concentration to ingress into the estuary. Here, larvae exhibit a rheotaxis behavior and avoid displacement by longshore currents by keeping bearing during navigation. When larvae reach the vicinity of an estuary, merging diel rhythms with feeding and predator avoidance strategies with tidally induced movements is essential to increase their chances of estuarine ingress. A fish larva recruitment model developed for the Ria Formosa lagoon supports the general framework of the SAAB hypothesis. In

  19. Biotic games and cloud experimentation as novel media for biophysics education

    Science.gov (United States)

    Riedel-Kruse, Ingmar; Blikstein, Paulo

    2014-03-01

    First-hand, open-ended experimentation is key for effective formal and informal biophysics education. We developed, tested and assessed multiple new platforms that enable students and children to directly interact with and learn about microscopic biophysical processes: (1) Biotic games that enable local and online play using galvano- and photo-tactic stimulation of micro-swimmers, illustrating concepts such as biased random walks, Low Reynolds number hydrodynamics, and Brownian motion; (2) an undergraduate course where students learn optics, electronics, micro-fluidics, real time image analysis, and instrument control by building biotic games; and (3) a graduate class on the biophysics of multi-cellular systems that contains a cloud experimentation lab enabling students to execute open-ended chemotaxis experiments on slimemolds online, analyze their data, and build biophysical models. Our work aims to generate the equivalent excitement and educational impact for biophysics as robotics and video games have had for mechatronics and computer science, respectively. We also discuss how scaled-up cloud experimentation systems can support MOOCs with true lab components and life-science research in general.

  20. Inventory parameters

    CERN Document Server

    Sharma, Sanjay

    2017-01-01

    This book provides a detailed overview of various parameters/factors involved in inventory analysis. It especially focuses on the assessment and modeling of basic inventory parameters, namely demand, procurement cost, cycle time, ordering cost, inventory carrying cost, inventory stock, stock out level, and stock out cost. In the context of economic lot size, it provides equations related to the optimum values. It also discusses why the optimum lot size and optimum total relevant cost are considered to be key decision variables, and uses numerous examples to explain each of these inventory parameters separately. Lastly, it provides detailed information on parameter estimation for different sectors/products. Written in a simple and lucid style, it offers a valuable resource for a broad readership, especially Master of Business Administration (MBA) students.

  1. Effect of ambient light on the time needed to complete a fetal biophysical profile: A randomized controlled trial.

    Science.gov (United States)

    Said, Heather M; Gupta, Shweta; Vricella, Laura K; Wand, Katy; Nguyen, Thinh; Gross, Gilad

    2017-10-01

    The objective of this study is to determine whether ambient light serves as a fetal stimulus to decrease the amount of time needed to complete a biophysical profile. This is a randomized controlled trial of singleton gestations undergoing a biophysical profile. Patients were randomized to either ambient light or a darkened room. The primary outcome was the time needed to complete the biophysical profile. Secondary outcomes included total and individual component biophysical profile scores and scores less than 8. A subgroup analysis of different maternal body mass indices was also performed. 357 biophysical profile studies were analyzed. 182 studies were performed with ambient light and 175 were performed in a darkened room. There was no difference in the median time needed to complete the biophysical profile based on exposure to ambient light (6.1min in darkened room versus 6.6min with ambient light; P=0.73). No difference was found in total or individual component biophysical profile scores. Subgroup analysis by maternal body mass index did not demonstrate shorter study times with ambient light exposure in women who were normal weight, overweight or obese. Ambient light exposure did not decrease the time needed to complete the biophysical profile. There was no evidence that ambient light altered fetal behavior observed during the biophysical profile. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Unexplored biophysical problem of manned flight to Mars

    Science.gov (United States)

    Avakyan, Sergey; Voronin, Nikolai; Kovalenok, Vladimir; Trchounian, Armen

    The presentation discusses so far unexplored biophysical problem of manned flight to the Mars, scheduled for the next decade. In long-term manned space flights on the orbital stations "Salyut-6" Soviet cosmonaut crews under the command of one of the co-authors (cosmonaut V.V. Kovalenok) had repeatedly observed the effect of certain geophysical conditions on the psychological state of each crew. These effects were coinciding with the increased intensity of global illumination in the upper ionosphere space on flight altitudes (300-360 km). It is important that, during all these periods, the geomagnetic pulsation's were completely absent. Previously a new but very important for long interplanetary expeditions problem of psychophysical state of the crew in the absence of alternating electromagnetic fields and radiation, including the ionosphere one, was first raised for evolutionarily adapted humanity. However, up to date, this subject, particularly during the long simulation experiments such as "Mars 500", which eliminates much of their value and contribution to the Mars mission, has almost no attention. Indeed, the obtained results have clearly shown that the cosmonaut crews in orbital flight, even deep one within geomagnetic sphere, might experience severe psychological discomfort, the nature of which is fully defined. This is the appearance of such rather unusual geophysical periods of different durations (from minutes to days) those are in the form of an almost complete lack of geomagnetic pulsations on the Earth. The aim is to confirm the need of considering possible pathological effects of the complete lack of rhythm forming, inherent for terrestrial environment geomagnetic pulsation's on psychological and physical state of the cosmonaut crew. This is important for the preparation and conducting the manned flights beyond the Earth's magnetosphere, particularly to the Mars. The influence of the presence of different types of geomagnetic pulsation's recorded by

  3. Minding the close relationship.

    Science.gov (United States)

    Harvey, J H; Omarzu, J

    1997-01-01

    In this theoretical analysis, we argue that a process referred to as minding is essential for a couple to feel mutually close and satisfied in a close relationship over a long period Minding represents a package of mutual self-disclosure, other forms of goal-oriented behavior aimed at facilitating the relationship, and attributions about self's and other's motivations, intentions, and Mort in the relationship. Self-disclosure and attribution activities in minding are aimed at getting to know the other, trying to understand the other's motivations and deeper disposition as they pertain to the relationship, and showing respect and acceptance for knowledge gained about other. We link the concept of minding to other major ideas and literatures about how couples achieve closeness: self-disclosure and social penetration, intimacy, empathy and empathic accuracy, and love and self-expansion. We argue that the minding process articulated here has not previously been delineated and that it is a useful composite notion about essential steps in bonding among humans. We also argue that the minding concept stretches our understanding of the interface of attribution and close relationships. We present research possibilities and implications and consider possible alternative positions and counter arguments about the merits of the minding idea for close relationship satisfaction.

  4. X-Ray structure and biophysical properties of rabbit fibroblast growth factor 1

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jihun; Blaber, Sachiko I.; Irsigler, Andre; Aspinwall, Eric; Blaber, Michael; (FSU)

    2010-01-14

    The rabbit is an important and de facto animal model in the study of ischemic disease and angiogenic therapy. Additionally, fibroblast growth factor 1 (FGF-1) is emerging as one of the most important growth factors for novel pro-angiogenic and pro-arteriogenic therapy. However, despite its significance, the fundamental biophysical properties of rabbit FGF-1, including its X-ray structure, have never been reported. Here, the cloning, crystallization, X-ray structure and determination of the biophysical properties of rabbit FGF-1 are described. The X-ray structure shows that the amino-acid differences between human and rabbit FGF-1 are solvent-exposed and therefore potentially immunogenic, while the biophysical studies identify differences in thermostability and receptor-binding affinity that distinguish rabbit FGF-1 from human FGF-1.

  5. Predictive biophysical modeling and understanding of the dynamics of mRNA translation and its evolution

    Science.gov (United States)

    Zur, Hadas; Tuller, Tamir

    2016-01-01

    mRNA translation is the fundamental process of decoding the information encoded in mRNA molecules by the ribosome for the synthesis of proteins. The centrality of this process in various biomedical disciplines such as cell biology, evolution and biotechnology, encouraged the development of dozens of mathematical and computational models of translation in recent years. These models aimed at capturing various biophysical aspects of the process. The objective of this review is to survey these models, focusing on those based and/or validated on real large-scale genomic data. We consider aspects such as the complexity of the models, the biophysical aspects they regard and the predictions they may provide. Furthermore, we survey the central systems biology discoveries reported on their basis. This review demonstrates the fundamental advantages of employing computational biophysical translation models in general, and discusses the relative advantages of the different approaches and the challenges in the field. PMID:27591251

  6. Ultrasound assessment of the fetal biophysical profile: What does an radiologist need to know?

    International Nuclear Information System (INIS)

    Guimaraes Filho, Helio Antonio; Araujo Junior, Edward; Marcondes Machado Nardozza, Luciano; Linhares Dias da Costa, Lavoisier; Fernandes Moron, Antonio; Mattar, Rosiane

    2008-01-01

    Proposed by Frank Manning about 26 years ago, fetal biophysical profile has been incorporated to the propaedeutics of non-invasive fetal well being assessment in high-risk gestations. Despite the existence of other methods for assessing fetal vitality, as Doppler flowmetry, the biophysical profile continues to be important in estimating the risk of hypoxia and perinatal morbimortality for those fetuses. In the present article, the authors review the regulatory mechanisms of fetal biophysical activities, as well as physiological and pathological factors that interfere with them. The main objective of the study is to discuss the present and important aspects of the method, and the practical applications and interpretation of its findings, in order to help radiologists improve their knowledge in this specific area of fetal ultrasonography

  7. Close binary stars

    International Nuclear Information System (INIS)

    Larsson-Leander, G.

    1979-01-01

    Studies of close binary stars are being persued more vigorously than ever, with about 3000 research papers and notes pertaining to the field being published during the triennium 1976-1978. Many major advances and spectacular discoveries were made, mostly due to increased observational efficiency and precision, especially in the X-ray, radio, and ultraviolet domains. Progress reports are presented in the following areas: observational techniques, methods of analyzing light curves, observational data, physical data, structure and models of close binaries, statistical investigations, and origin and evolution of close binaries. Reports from the Coordinates Programs Committee, the Committee for Extra-Terrestrial Observations and the Working Group on RS CVn binaries are included. (Auth./C.F.)

  8. The biophysical link between climate, water, and vegetation in bioenergy agro-ecosystems

    International Nuclear Information System (INIS)

    Bagley, Justin E.; Davis, Sarah C.; Georgescu, Matei; Hussain, Mir Zaman; Miller, Jesse; Nesbitt, Stephen W.; VanLoocke, Andy; Bernacchi, Carl J.

    2014-01-01

    Land use change for bioenergy feedstocks is likely to intensify as energy demand rises simultaneously with increased pressure to minimize greenhouse gas emissions. Initial assessments of the impact of adopting bioenergy crops as a significant energy source have largely focused on the potential for bioenergy agroecosystems to provide global-scale climate regulating ecosystem services via biogeochemical processes. Such as those processes associated with carbon uptake, conversion, and storage that have the potential to reduce global greenhouse gas emissions (GHG). However, the expansion of bioenergy crops can also lead to direct biophysical impacts on climate through water regulating services. Perturbations of processes influencing terrestrial energy fluxes can result in impacts on climate and water across a spectrum of spatial and temporal scales. Here, we review the current state of knowledge about biophysical feedbacks between vegetation, water, and climate that would be affected by bioenergy-related land use change. The physical mechanisms involved in biophysical feedbacks are detailed, and interactions at leaf, field, regional, and global spatial scales are described. Locally, impacts on climate of biophysical changes associated with land use change for bioenergy crops can meet or exceed the biogeochemical changes in climate associated with rising GHG's, but these impacts have received far less attention. Realization of the importance of ecosystems in providing services that extend beyond biogeochemical GHG regulation and harvestable yields has led to significant debate regarding the viability of various feedstocks in many locations. The lack of data, and in some cases gaps in knowledge associated with biophysical and biochemical influences on land–atmosphere interactions, can lead to premature policy decisions. - Highlights: • The physical basis for biophysical impacts of expanding bioenergy agroecosystems on climate and water is described. • We

  9. Sensitivity of microwave ablation models to tissue biophysical properties: A first step toward probabilistic modeling and treatment planning.

    Science.gov (United States)

    Sebek, Jan; Albin, Nathan; Bortel, Radoslav; Natarajan, Bala; Prakash, Punit

    2016-05-01

    Computational models of microwave ablation (MWA) are widely used during the design optimization of novel devices and are under consideration for patient-specific treatment planning. The objective of this study was to assess the sensitivity of computational models of MWA to tissue biophysical properties. The Morris method was employed to assess the global sensitivity of the coupled electromagnetic-thermal model, which was implemented with the finite element method (FEM). The FEM model incorporated temperature dependencies of tissue physical properties. The variability of the model was studied using six different outputs to characterize the size and shape of the ablation zone, as well as impedance matching of the ablation antenna. Furthermore, the sensitivity results were statistically analyzed and absolute influence of each input parameter was quantified. A framework for systematically incorporating model uncertainties for treatment planning was suggested. A total of 1221 simulations, incorporating 111 randomly sampled starting points, were performed. Tissue dielectric parameters, specifically relative permittivity, effective conductivity, and the threshold temperature at which they transitioned to lower values (i.e., signifying desiccation), were identified as the most influential parameters for the shape of the ablation zone and antenna impedance matching. Of the thermal parameters considered in this study, the nominal blood perfusion rate and the temperature interval across which the tissue changes phase were identified as the most influential. The latent heat of tissue water vaporization and the volumetric heat capacity of the vaporized tissue were recognized as the least influential parameters. Based on the evaluation of absolute changes, the most important parameter (perfusion) had approximately 40.23 times greater influence on ablation area than the least important parameter (volumetric heat capacity of vaporized tissue). Another significant input parameter

  10. A note on the roles of quantum and mechanical models in social biophysics.

    Science.gov (United States)

    Takahashi, Taiki; Kim, Song-Ju; Naruse, Makoto

    2017-11-01

    Recent advances in the applications of quantum models into various disciplines such as cognitive science, social sciences, economics, and biology witnessed enormous achievements and possible future progress. In this paper, we propose one of the most promising directions in the applications of quantum models: the combination of quantum and mechanical models in social biophysics. The possible resulting discipline may be called as experimental quantum social biophysics and could foster our understandings of the relationships between the society and individuals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Biophysics of directional hearing in the frog Eleutherodactylus coqui

    DEFF Research Database (Denmark)

    Jørgensen, Morten Buhl; Schmitz, Barbara; Christensen-Dalsgaard, Jakob

    1991-01-01

    1. We used laser vibrometry and free field sound stimulation to study the frequency responses of the eardrum and the lateral body wall of awake male Eleutherodactylus coqui. 2. The eardrum snowed one of two distinct frequency responses depending on whether the glottis was open (GO response) or cl...... of the eardrum even when the glottis is closed. 7. The vibration amplitude of the eardrum changed with the angle of sound incidence. The directionality was most pronounced in a narrow frequency range between the two main frequencies of the conspecific advertisement call....

  12. Biophysical Determinants of Front-Crawl Swimming at Moderate and Severe Intensities.

    Science.gov (United States)

    Ribeiro, João; Toubekis, Argyris G; Figueiredo, Pedro; de Jesus, Kelly; Toussaint, Huub M; Alves, Francisco; Vilas-Boas, João P; Fernandes, Ricardo J

    2017-02-01

    To conduct a biophysical analysis of the factors associated with front-crawl performance at moderate and severe swimming intensities, represented by anaerobic-threshold (vAnT) and maximal-oxygen-uptake (vV̇O 2 max) velocities. Ten high-level swimmers performed 2 intermittent incremental tests of 7 × 200 and 12 × 25 m (through a system of underwater push-off pads) to assess vAnT, and vV̇O 2 max, and power output. The 1st protocol was videotaped (3D reconstruction) for kinematic analysis to assess stroke frequency (SF), stroke length (SL), propelling efficiency (η P ), and index of coordination (IdC). V̇O 2 was measured and capillary blood samples (lactate concentrations) were collected, enabling computation of metabolic power. The 2nd protocol allowed calculating mechanical power and performance efficiency from the ratio of mechanical to metabolic power. Neither vAnT nor vV̇O 2 max was explained by SF (0.56 ± 0.06 vs 0.68 ± 0.06 Hz), SL (2.29 ± 0.21 vs 2.06 ± 0.20 m), η P (0.38 ± 0.02 vs 0.36± 0.03), IdC (-12.14 ± 5.24 vs -9.61 ± 5.49), or metabolic-power (1063.00 ± 122.90 vs 1338.18 ± 127.40 W) variability. vV̇O 2 max was explained by power to overcome drag (r = .77, P ≤ .05) and η P (r = .72, P ≤ .05), in contrast with the nonassociation between these parameters and vAnT; both velocities were well related (r = .62, P ≤ .05). The biomechanical parameters, coordination, and metabolic power seemed not to be performance discriminative at either intensity. However, the increase in power to overcome drag, for the less metabolic input, should be the focus of any intervention that aims to improve performance at severe swimming intensity. This is also true for moderate intensities, as vAnT and vV˙O2max are proportional to each other.

  13. Physiological and Biophysical Studies on Gamma Irradiated Rat Treated with Dehydroepiandrosterone Sulfate (DHEAS)

    International Nuclear Information System (INIS)

    Hamza, G.R.A.

    2015-01-01

    Dehydroepiandrosterone Sulfate (DHEAS) is an adrenal hormone, and is the most abundant circulatory steroid hormone in the body. Serum DHEAS concentration peaks at around age 25 years, displaying a significant decrease with age linked with some pathological changes. Objective: This study was performed to investigate the effect(s) of DHEAS oral administration, and its possible prophylactic and/or mitigating roles against γ-irradiation-induced disorders in the irradiated rat. Experimental Animals and Design: Five groups of male Albino rats were used: 1- Control: untreated group. 2- Irradiated: animals exposed to a single dose of whole-body γ-irradiation (6 Gy). 3- DHEAS group: given a single dose of DHEAS (20 mg/100 g b. wt.), intra gastrically. 4-DHEAS + Irrad. group: given a single dose of DHEAS, 2 hrs before irradiation. 5- Irrad.+ DHEAS group: given DHEAS, 2 hrs after irradiation. Blood and testicular tissue samples were collected after one day, one week and two weeks post irradiation or DHEAS treatment. Parameters Measured: Plasma levels of triiodothyronine (T 3 ), thyroxin (T 4 ), thyrotropin (TSH), testosterone, acid phosphatase (ACP), triglycerides (TG), total cholesterol, high density lipoprotein-cholesterol (HDL-Ch), low density lipoprotein-cholesterol (LDL-Ch) were determined, and the atherogenic index (AI) was calculated. Reduced glutathione (GSH) content and malondialdehyde (MDA) levels were measured in blood and testes. A complete blood picture and some biophysical properties were also examined. Results: DHEAS administration pre-irradiation, and to a lesser magnitude, post-irradiation, improved the disturbances induced by irradiation in the plasma levels of the tested parameters: tT 3 , tT 4 , and TSH, testosterone and the lipid profile, showing almost normalization of the AI. Beneficial effects were also observed in the hematological picture, blood viscosity and conductivity. DHEAS elevated GSH levels and decreased lipid peroxidation (LPO) in blood

  14. Assessment of biophysical tumor response to PDT in pancreatic cancer using localized reflectance spectroscopy

    Science.gov (United States)

    Isabelle, Martin; Klubben, William; He, Ting; Laughney, Ashley M.; Glaser, Adam; Krishnaswamy, Venkataramanan; Hoopes, P. Jack; Hasan, Tayyaba; Pogue, Brian W.

    2011-02-01

    Biophysical changes such as inflammation and necrosis occur immediately following PDT and may be used to assess the treatment response to PDT treatment in-vivo. This study uses localized reflectance measurements to quantify the scatter changes in tumor tissue occurring in response to verteporfin-based PDT treatment in xenograft pancreas tumors. Nude mice were implanted with subcutaneous AsPC-1 pancreatic tumors cells in matrigel, and allowed to establish solid tumors near 100mm3 volume. The mice were sensitized with 1mg/kg of the active component of verteporfin (benzoporphryin derivative, BPD), one hour before light delivery. The optical irradiation was performed using a 1 cm cylindrical interstitial diffusing tip fiber with 20J of red light (690nm). Tumor tissue was excised progressively and imaged, from 1 day to 4 weeks, after PDT treatment. The tissue sections were stained and analyzed by an expert veterinary pathologist, who provided information on tissue regions of interest. This information was correlated with variations in scattering and absorption parameters elucidated from the spectral images and the degree of necrosis and inflammation involvement was identified. Areas of necrosis and dead cells exhibited the lowest average scatter irradiance signature (3.78 and 4.07 respectively) compared to areas of viable pancreatic tumor cells and areas of inflammation (5.81 and 7.19 respectively). Bilirubin absorbance parameters also showed a lower absorbance value in necrotic tissue and areas of dead cells (0.05 and 0.1 respectively) compared to tissue areas for viable pancreatic tumor cells and areas of inflammation (0.28 and 0.35). These results demonstrate that localized reflectance spectroscopy is an imaging modality that can be used to identify tissue features associated with PDT treatment (e.g. necrosis and inflammation) that can be correlated with histopathologically-reviewed H&E stained slides. Further study of this technique may provide means for automated

  15. NRC closing remarks

    International Nuclear Information System (INIS)

    Coffman, F.

    1994-01-01

    This section contains the edited transcript of the NRC closing remarks made by Mr. Franklin Coffman (Chief, Human Factors Branch, Office of Nuclear Regulatory Research) and Dr. Cecil Thomas (Deputy Director, Division of Reactor Controls and Human Factors, Office of Nuclear Reactor Regulation). This editing consisted of minimal editing to correct grammar and remove extraneous references to microphone volume, etc

  16. Biophysical properties of the normal-sized aorta in patients with Marfan syndrome: evaluation with MR flow mapping

    NARCIS (Netherlands)

    Groenink, M.; de Roos, A.; Mulder, B. J.; Verbeeten, B.; Timmermans, J.; Zwinderman, A. H.; Spaan, J. A.; van der Wall, E. E.

    2001-01-01

    PURPOSE: To investigate the feasibility of magnetic resonance (MR) flow mapping in the assessment of aortic biophysical properties in patients with Marfan syndrome and to detect differences in biophysical properties in the normal-sized aorta distal to the aortic root between these patients and

  17. A spectral mean for random closed curves

    NARCIS (Netherlands)

    van Lieshout, Maria Nicolette Margaretha

    2016-01-01

    We propose a spectral mean for closed sets described by sample points on their boundaries subject to mis-alignment and noise. We derive maximum likelihood estimators for the model and noise parameters in the Fourier domain. We estimate the unknown mean boundary curve by back-transformation and

  18. A spectral mean for random closed curves

    NARCIS (Netherlands)

    M.N.M. van Lieshout (Marie-Colette)

    2016-01-01

    textabstractWe propose a spectral mean for closed sets described by sample points on their boundaries subject to mis-alignment and noise. We derive maximum likelihood estimators for the model and noise parameters in the Fourier domain. We estimate the unknown mean boundary curve by

  19. Human Visual System as a Double-Slit Single Photon Interference Sensor: A Comparison between Modellistic and Biophysical Tests

    Science.gov (United States)

    Pizzi, Rita; Wang, Rui; Rossetti, Danilo

    2016-01-01

    This paper describes a computational approach to the theoretical problems involved in the Young's single-photon double-slit experiment, focusing on a simulation of this experiment in the absence of measuring devices. Specifically, the human visual system is used in place of a photomultiplier or similar apparatus. Beginning with the assumption that the human eye perceives light in the presence of very few photons, we measure human eye performance as a sensor in a double-slit one-photon-at-a-time experimental setup. To interpret the results, we implement a simulation algorithm and compare its results with those of human subjects under identical experimental conditions. In order to evaluate the perceptive parameters exactly, which vary depending on the light conditions and on the subject’s sensitivity, we first review the existing literature on the biophysics of the human eye in the presence of a dim light source, and then use the known values of the experimental variables to set the parameters of the computational simulation. The results of the simulation and their comparison with the experiment involving human subjects are reported and discussed. It is found that, while the computer simulation indicates that the human eye has the capacity to detect the corpuscular nature of photons under these conditions, this was not observed in practice. The possible reasons for the difference between theoretical prediction and experimental results are discussed. PMID:26816029

  20. Human Visual System as a Double-Slit Single Photon Interference Sensor: A Comparison between Modellistic and Biophysical Tests.

    Directory of Open Access Journals (Sweden)

    Rita Pizzi

    Full Text Available This paper describes a computational approach to the theoretical problems involved in the Young's single-photon double-slit experiment, focusing on a simulation of this experiment in the absence of measuring devices. Specifically, the human visual system is used in place of a photomultiplier or similar apparatus. Beginning with the assumption that the human eye perceives light in the presence of very few photons, we measure human eye performance as a sensor in a double-slit one-photon-at-a-time experimental setup. To interpret the results, we implement a simulation algorithm and compare its results with those of human subjects under identical experimental conditions. In order to evaluate the perceptive parameters exactly, which vary depending on the light conditions and on the subject's sensitivity, we first review the existing literature on the biophysics of the human eye in the presence of a dim light source, and then use the known values of the experimental variables to set the parameters of the computational simulation. The results of the simulation and their comparison with the experiment involving human subjects are reported and discussed. It is found that, while the computer simulation indicates that the human eye has the capacity to detect the corpuscular nature of photons under these conditions, this was not observed in practice. The possible reasons for the difference between theoretical prediction and experimental results are discussed.

  1. The gastro-esophageal reflux barrier: biophysical analysis on 3D models of anatomy from magnetic resonance imaging.

    Science.gov (United States)

    Roy, S; Fox, M R; Curcic, J; Schwizer, W; Pal, A

    2012-07-01

    The function and structure of the gastro-esophageal junction (GEJ) determine its efficacy as a reflux barrier. This study presents a novel methodology for the quantitative assessment of GEJ and proximal gastric morphology from magnetic resonance (MR) imaging. Based on this data we propose a new conceptualization of the hypothesis that a flap valve mechanism contributes to reflux protection. 3D models of the GEJ and proximal stomach were reconstructed from MR images in 12 healthy volunteers during respiration and on eating a test meal to maximum satiation. A rotating plane analysis measured the gastro-esophageal insertion angle and span of contact. An ellipsoid fit provided quantitative assessment of gastric shape and orientation relative to a fixed anatomical reference point. Position of the esophageal insertion on the 'gastric ellipse' was noted. An ellipsoid-cylinder model was designed to analyze the relationships among parameters describing the GEJ morphology. The insertion angle became more acute on expiration, but did not change with meal ingestion. In contrast the span of contact did not vary with respiration, but increased with gastric filling. Changes in gastric morphology with distension further augmented the span of gastro-esophageal contact in almost 70% of the studies. Novel MR imaging and biophysical analysis of the GEJ and proximal stomach provide a quantitative description of structures contributing to the reflux barrier. Changes in these parameters during respiration and on eating support the hypothesis that structural components of a functional 'flap valve' like mechanism contribute to reflux protection. © 2012 Blackwell Publishing Ltd.

  2. Summaries of fiscal year 1994 projects in medical applications and biophysical research

    International Nuclear Information System (INIS)

    1995-04-01

    This report provides information on the research supported in Fiscal Year 1994 by the Medical Applications and Biophysical Research Division of the Office of Health and Environmental Research. A brief statement of the scope of the following areas is presented: dosimetry; measurement science; radiological and chemical physics; structural biology; human genome; and medical applications. Summaries of the research projects in these categories are presented

  3. Simulated Local and Remote Biophysical Effects of Afforestation over the Southeast United States in Boreal Summer

    Science.gov (United States)

    Guang-Shan Chen; Michael Notaro; Zhengyu Liu; Yongqiang Liu

    2012-01-01

    Afforestation has been proposed as a climate change mitigation strategy by sequestrating atmospheric carbon dioxide. With the goal of increasing carbon sequestration, a Congressional project has been planned to afforest about 18 million acres by 2020 in the Southeast United States (SEUS), the Great Lake states, and the Corn Belt states. However, biophysical feedbacks...

  4. Coupling Biophysical and Socioeconomic Models for Coral Reef Systems in Quintana Roo, Mexican Caribbean

    Directory of Open Access Journals (Sweden)

    Jessica Melbourne-Thomas

    2011-09-01

    Full Text Available Transdisciplinary approaches that consider both socioeconomic and biophysical processes are central to understanding and managing rapid change in coral reef systems worldwide. To date, there have been limited attempts to couple the two sets of processes in dynamic models for coral reefs, and these attempts are confined to reef systems in developed countries. We present an approach to coupling existing biophysical and socioeconomic models for coral reef systems in the Mexican state of Quintana Roo. The biophysical model is multiscale, using dynamic equations to capture local-scale ecological processes on individual reefs, with reefs connected at regional scales by the ocean transport of larval propagules. The agent-based socioeconomic model simulates changes in tourism, fisheries, and urbanization in the Quintana Roo region. Despite differences in the formulation and currencies of the two models, we were able to successfully modify and integrate them to synchronize and define information flows and feedbacks between them. A preliminary evaluation of the coupled model system indicates that the model gives reasonable predictions for fisheries and ecological variables and can be used to examine scenarios for future social-ecological change in Quintana Roo. We provide recommendations for where efforts might usefully be focused in future attempts to integrate models of biophysical and socioeconomic processes, based on the limitations of our coupled system.

  5. Biophysical properties and functional significance of stem water storage tissues in Neotropical savanna trees.

    Science.gov (United States)

    F.G. Scholz; S.J. Bucci; G. Goldstein; F.C. Meinzer; A.C. Franco; F. Miralles-Wilhelm

    2007-01-01

    Biophysical characteristics of sapwood and outer parenchyma water storage compartments were studied in stems of eight dominant Brazilian Cerrado tree species to assess the impact of differences in tissue capacitance on whole-plant water relations. Both the sapwood and outer parenchyma tissues played an important role in regulation of internal water deficits of Cerrado...

  6. Coupling the biophysical and social dimensions of wildfire risk to improve wildfire mitigation planning

    Science.gov (United States)

    Alan A. Ager; Jeffrey D. Kline; A. Paige Fisher

    2015-01-01

    We describe recent advances in biophysical and social aspects of risk and their potential combined contribution to improve mitigation planning on fire-prone landscapes. The methods and tools provide an improved method for defining the spatial extent of wildfire risk to communities compared to current planning processes. They also propose an expanded role for social...

  7. A multivariate decision tree analysis of biophysical factors in tropical forest fire occurrence

    Science.gov (United States)

    Rey S. Ofren; Edward Harvey

    2000-01-01

    A multivariate decision tree model was used to quantify the relative importance of complex hierarchical relationships between biophysical variables and the occurrence of tropical forest fires. The study site is the Huai Kha Kbaeng wildlife sanctuary, a World Heritage Site in northwestern Thailand where annual fires are common and particularly destructive. Thematic...

  8. Biochemical and Biophysical Cues in Matrix Design for Chronic and Diabetic Wound Treatment.

    Science.gov (United States)

    Xiao, Yun; Ahadian, Samad; Radisic, Milica

    2017-02-01

    Progress in biomaterial science and engineering and increasing knowledge in cell biology have enabled us to develop functional biomaterials providing appropriate biochemical and biophysical cues for tissue regeneration applications. Tissue regeneration is particularly important to treat chronic wounds of people with diabetes. Understanding and controlling the cellular microenvironment of the wound tissue are important to improve the wound healing process. In this study, we review different biochemical (e.g., growth factors, peptides, DNA, and RNA) and biophysical (e.g., topographical guidance, pressure, electrical stimulation, and pulsed electromagnetic field) cues providing a functional and instructive acellular matrix to heal diabetic chronic wounds. The biochemical and biophysical signals generally regulate cell-matrix interactions and cell behavior and function inducing the tissue regeneration for chronic wounds. Some technologies and devices have already been developed and used in the clinic employing biochemical and biophysical cues for wound healing applications. These technologies can be integrated with smart biomaterials to deliver therapeutic agents to the wound tissue in a precise and controllable manner. This review provides useful guidance in understanding molecular mechanisms and signals in the healing of diabetic chronic wounds and in designing instructive biomaterials to treat them.

  9. Riparian influences on the biophysical characteristics of seston in headwater streams.

    Science.gov (United States)

    Scott R. Elliott; Robert J. Naiman; Peter A. Bisson

    2004-01-01

    Suspended particles (seston) in streams are an important source of nutrition for many invertebrates, forming a strong trophic link between plant and animal production. In forested regions the management of riparian corridors may alter alloehthonous and autochthonous contributions to streams, ultimately changing the biophysical characteristics of seston. This article...

  10. Canopy-scale biophysical controls on transpiration and evaporation in the Amazon Basin

    DEFF Research Database (Denmark)

    Mallick, Kaniska; Trebs, Ivonne; Bøgh, Eva

    2016-01-01

    to directly quantify the canopy-scale biophysical controls on λET and λEE over multiple plant functional types (PFTs) in the Amazon Basin. Combining data from six LBA (Large-scale Biosphere-Atmosphere Experiment in Amazonia) eddy covariance tower sites and a TR-driven physically based modeling approach, we...

  11. 6th international conference on biophysics and synchrotron radiation. Program/Abstracts

    International Nuclear Information System (INIS)

    Pittroff, Connie; Strasser, Susan Barr

    1999-01-01

    This STI product consists of the Program/Abstracts book that was prepared for the participants in the Sixth International Conference on Biophysics and Synchrotron Radiation that was held August 4-8, 1998, at the Advanced Photon Source, Argonne National Laboratory. This book contains the full conference program and abstracts of the scientific presentations

  12. Biophysical characterization of the proton-coupled oligopeptide transporter YjdL

    DEFF Research Database (Denmark)

    Jensen, Johanne Mørch; Simonsen, Fie C.; Mastali, Amir

    2012-01-01

    significantly different from prototypical POTs such as the human hPepT1. Nonetheless YjdL contains several highly conserved POT residues, which include Glu388 that is located in the putative substrate binding cavity. Here we present biophysical characterization of WT-YjdL and Glu388Gln. Isothermal titration...

  13. Direct Scaling of Leaf-Resolving Biophysical Models from Leaves to Canopies

    Science.gov (United States)

    Bailey, B.; Mahaffee, W.; Hernandez Ochoa, M.

    2017-12-01

    Recent advances in the development of biophysical models and high-performance computing have enabled rapid increases in the level of detail that can be represented by simulations of plant systems. However, increasingly detailed models typically require increasingly detailed inputs, which can be a challenge to accurately specify. In this work, we explore the use of terrestrial LiDAR scanning data to accurately specify geometric inputs for high-resolution biophysical models that enables direct up-scaling of leaf-level biophysical processes. Terrestrial LiDAR scans generate "clouds" of millions of points that map out the geometric structure of the area of interest. However, points alone are often not particularly useful in generating geometric model inputs, as additional data processing techniques are required to provide necessary information regarding vegetation structure. A new method was developed that directly reconstructs as many leaves as possible that are in view of the LiDAR instrument, and uses a statistical backfilling technique to ensure that the overall leaf area and orientation distribution matches that of the actual vegetation being measured. This detailed structural data is used to provide inputs for leaf-resolving models of radiation, microclimate, evapotranspiration, and photosynthesis. Model complexity is afforded by utilizing graphics processing units (GPUs), which allows for simulations that resolve scales ranging from leaves to canopies. The model system was used to explore how heterogeneity in canopy architecture at various scales affects scaling of biophysical processes from leaves to canopies.

  14. 6th international conference on biophysics and synchrotron radiation. Program/Abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Pittroff, Connie; Strasser, Susan Barr [lead editors

    1999-08-03

    This STI product consists of the Program/Abstracts book that was prepared for the participants in the Sixth International Conference on Biophysics and Synchrotron Radiation that was held August 4-8, 1998, at the Advanced Photon Source, Argonne National Laboratory. This book contains the full conference program and abstracts of the scientific presentations.

  15. A dataset mapping the potential biophysical effects of vegetation cover change

    Science.gov (United States)

    Duveiller, Gregory; Hooker, Josh; Cescatti, Alessandro

    2018-02-01

    Changing the vegetation cover of the Earth has impacts on the biophysical properties of the surface and ultimately on the local climate. Depending on the specific type of vegetation change and on the background climate, the resulting competing biophysical processes can have a net warming or cooling effect, which can further vary both spatially and seasonally. Due to uncertain climate impacts and the lack of robust observations, biophysical effects are not yet considered in land-based climate policies. Here we present a dataset based on satellite remote sensing observations that provides the potential changes i) of the full surface energy balance, ii) at global scale, and iii) for multiple vegetation transitions, as would now be required for the comprehensive evaluation of land based mitigation plans. We anticipate that this dataset will provide valuable information to benchmark Earth system models, to assess future scenarios of land cover change and to develop the monitoring, reporting and verification guidelines required for the implementation of mitigation plans that account for biophysical land processes.

  16. Winnowing and Flocculation in Bio-physical Cohesive Substrate: A Flume Experimental and Estuarine Study

    Science.gov (United States)

    Ye, L.; Parsons, D. R.; Manning, A. J.

    2016-12-01

    Cohesive sediment, or mud, is ubiquitously found in most aqueous environments, such as coasts and estuaries. The study of cohesive sediment behaviors requires the synchronous description of mutual interactions of grains (e.g., winnowing and flocculation), their physical properties (e.g., grain size) and also the ambient water. Herein, a series of flume experiments (14 runs) with different substrate mixtures of sand-clay-EPS (Extracellular Polymeric Substrates: secreted by aquatic microorganisms) are combined with an estuarine field survey (Dee estuary, NW England) to investigate the behavior of suspensions over bio-physical cohesive substrates. The experimental results indicate that winnowing and flocculation occur pervasively in bio-physical cohesive flow systems. Importantly however, the evolution of the bed and bedform dynamics and hence turbulence production can be lower when cohesivity is high. The estuarine survey also revealed that the bio-physical cohesion provided by both the clay and microorganism fractions in the bed, that pervasively exists in many natural estuarine systems, plays a significant role in controlling the interactions between bed substrate and sediment suspension and deposition, including controlling processes such as sediment winnowing, flocculation and re-deposition. Full understanding of these processes are essential in advancing sediment transport modelling and prediction studies across natural estuarine systems and the work will report on an improved conceptual model for sediment sorting deposition in bio-physical cohesive substrates.

  17. Adjusting policy to institutional, cultural and biophysical context conditions: The case of conservation banking in California

    Science.gov (United States)

    Carsten Mann; James D. Absher

    2013-01-01

    This paper examines the political construction of a policy instrument for matching particular institutional, biophysical and cultural context conditions in a social–ecological system, using the case of conservation banking in California as an example. The guiding research question is: How is policy design negotiated between various actors on its way from early...

  18. Bomb parameters

    International Nuclear Information System (INIS)

    Kerr, George D.; Young, Rebert W.; Cullings, Harry M.; Christry, Robert F.

    2005-01-01

    The reconstruction of neutron and gamma-ray doses at Hiroshima and Nagasaki begins with a determination of the parameters describing the explosion. The calculations of the air transported radiation fields and survivor doses from the Hiroshima and Nagasaki bombs require knowledge of a variety of parameters related to the explosions. These various parameters include the heading of the bomber when the bomb was released, the epicenters of the explosions, the bomb yields, and the tilt of the bombs at time of explosion. The epicenter of a bomb is the explosion point in air that is specified in terms of a burst height and a hypocenter (or the point on the ground directly below the epicenter of the explosion). The current reassessment refines the energy yield and burst height for the Hiroshima bomb, as well as the locations of the Hiroshima and Nagasaki hypocenters on the modern city maps used in the analysis of the activation data for neutrons and TLD data for gamma rays. (J.P.N.)

  19. Closing the loop.

    Science.gov (United States)

    Dassau, E; Atlas, E; Phillip, M

    2010-02-01

    The dream of closing the loop is actually the dream of creating an artificial pancreas and freeing the patients from being involved with the care of their own diabetes. Insulin-dependent diabetes (type 1) is a chronic incurable disease which requires constant therapy without the possibility of any 'holidays' or insulin-free days. It means that patients have to inject insulin every day of their life, several times per day, and in order to do it safely they also have to measure their blood glucose levels several times per day. Patients need to plan their meals, their physical activities and their insulin regime - there is only very small room for spontaneous activities. This is why the desire for an artificial pancreas is so strong despite the fact that it will not cure the diabetic patients. Attempts to develop a closed-loop system started in the 1960s but never got to a clinical practical stage of development. In recent years the availability of continuous glucose sensors revived those efforts and stimulated the clinician and researchers to believe that closing the loop might be possible nowadays. Many papers have been published over the years describing several different ideas on how to close the loop. Most of the suggested systems have a sensing arm that measures the blood glucose repeatedly or continuously, an insulin delivery arm that injects insulin upon command and a computer that makes the decisions of when and how much insulin to deliver. The differences between the various published systems in the literature are mainly in their control algorithms. However, there are also differences related to the method and site of glucose measurement and insulin delivery. SC glucose measurements and insulin delivery are the most studied option but other combinations of insulin measurements and glucose delivery including intravascular and intraperitoneal (IP) are explored. We tried to select recent publications that we believe had influenced and inspired people interested

  20. Effect of stimulation on the input parameters of stochastic leaky integrate-and-fire neuronal model

    Czech Academy of Sciences Publication Activity Database

    Lánský, Petr; Šanda, Pavel; He, J.

    2010-01-01

    Roč. 104, 3-4 (2010), s. 160-166 ISSN 0928-4257 R&D Projects: GA MŠk(CZ) LC554; GA AV ČR(CZ) IAA101120604 Institutional research plan: CEZ:AV0Z50110509 Keywords : membrane depolarization * input parameters * diffusion Subject RIV: BO - Biophysics Impact factor: 3.030, year: 2010

  1. Improvement of the accuracy by the measurement of the electrical cell membrane parameters

    Czech Academy of Sciences Publication Activity Database

    Rohlíček, Vojtěch; Rech, František

    2002-01-01

    Roč. 51, č. 2 (2002), s. 169-177 ISSN 0862-8408 Institutional research plan: CEZ:AV0Z5011922 Keywords : patch clamp technique * electrical parameters of the cell membrane * memebrane capacity Subject RIV: BO - Biophysics Impact factor: 0.984, year: 2002

  2. Past and Present Biophysical Redundancy of Countries as a Buffer to Changes in Food Supply

    Science.gov (United States)

    Fader, Marianela; Rulli, Maria Cristina; Carr, Joel; Dell' Angelo, Jampel; D' Odorico, Paolo; Gephart, Jessica A.; Kummu, Matti; Magliocca, Nicholas; Porkka, Miina; Prell, Christina; hide

    2016-01-01

    Spatially diverse trends in population growth, climate change, industrialization, urbanization and economic development are expected to change future food supply and demand. These changes may affect the suitability of land for food production, implying elevated risks especially for resource constrained, food-importing countries. We present the evolution of biophysical redundancy for agricultural production at country level, from 1992 to 2012. Biophysical redundancy, defined as unused biotic and abiotic environmental resources, is represented by the potential food production of 'spare land', available water resources (i.e., not already used for human activities), as well as production increases through yield gap closure on cultivated areas and potential agricultural areas. In 2012, the biophysical redundancy of 75 (48) countries, mainly in North Africa, Western Europe, the Middle East and Asia, was insufficient to produce the caloric nutritional needs for at least 50% (25%) of their population during a year. Biophysical redundancy has decreased in the last two decades in 102 out of 155 countries, 11 of these went from high to limited redundancy, and nine of these from limited to very low redundancy. Although the variability of the drivers of change across different countries is high, improvements in yield and population growth have a clear impact on the decreases of redundancy towards the very low redundancy category. We took a more detailed look at countries classified as 'Low Income Economies (LIEs)' since they are particularly vulnerable to domestic or external food supply changes, due to their limited capacity to offset for food supply decreases with higher purchasing power on the international market. Currently, nine LIEs have limited or very low biophysical redundancy. Many of these showed a decrease in redundancy over the last two decades, which is not always linked with improvements in per capita food availability.

  3. An ethnographic study: Becoming a physics expert in a biophysics research group

    Science.gov (United States)

    Rodriguez, Idaykis

    Expertise in physics has been traditionally studied in cognitive science, where physics expertise is understood through the difference between novice and expert problem solving skills. The cognitive perspective of physics experts only create a partial model of physics expertise and does not take into account the development of physics experts in the natural context of research. This dissertation takes a social and cultural perspective of learning through apprenticeship to model the development of physics expertise of physics graduate students in a research group. I use a qualitative methodological approach of an ethnographic case study to observe and video record the common practices of graduate students in their biophysics weekly research group meetings. I recorded notes on observations and conduct interviews with all participants of the biophysics research group for a period of eight months. I apply the theoretical framework of Communities of Practice to distinguish the cultural norms of the group that cultivate physics expert practices. Results indicate that physics expertise is specific to a topic or subfield and it is established through effectively publishing research in the larger biophysics research community. The participant biophysics research group follows a learning trajectory for its students to contribute to research and learn to communicate their research in the larger biophysics community. In this learning trajectory students develop expert member competencies to learn to communicate their research and to learn the standards and trends of research in the larger research community. Findings from this dissertation expand the model of physics expertise beyond the cognitive realm and add the social and cultural nature of physics expertise development. This research also addresses ways to increase physics graduate student success towards their PhD. and decrease the 48% attrition rate of physics graduate students. Cultivating effective research

  4. Past and present biophysical redundancy of countries as a buffer to changes in food supply

    Science.gov (United States)

    Fader, Marianela; Rulli, Maria Cristina; Carr, Joel; Dell'Angelo, Jampel; D'Odorico, Paolo; Gephart, Jessica A.; Kummu, Matti; Magliocca, Nicholas; Porkka, Miina; Prell, Christina; Puma, Michael J.; Ratajczak, Zak; Seekell, David A.; Suweis, Samir; Tavoni, Alessandro

    2016-05-01

    Spatially diverse trends in population growth, climate change, industrialization, urbanization and economic development are expected to change future food supply and demand. These changes may affect the suitability of land for food production, implying elevated risks especially for resource-constrained, food-importing countries. We present the evolution of biophysical redundancy for agricultural production at country level, from 1992 to 2012. Biophysical redundancy, defined as unused biotic and abiotic environmental resources, is represented by the potential food production of ‘spare land’, available water resources (i.e., not already used for human activities), as well as production increases through yield gap closure on cultivated areas and potential agricultural areas. In 2012, the biophysical redundancy of 75 (48) countries, mainly in North Africa, Western Europe, the Middle East and Asia, was insufficient to produce the caloric nutritional needs for at least 50% (25%) of their population during a year. Biophysical redundancy has decreased in the last two decades in 102 out of 155 countries, 11 of these went from high to limited redundancy, and nine of these from limited to very low redundancy. Although the variability of the drivers of change across different countries is high, improvements in yield and population growth have a clear impact on the decreases of redundancy towards the very low redundancy category. We took a more detailed look at countries classified as ‘Low Income Economies (LIEs)’ since they are particularly vulnerable to domestic or external food supply changes, due to their limited capacity to offset for food supply decreases with higher purchasing power on the international market. Currently, nine LIEs have limited or very low biophysical redundancy. Many of these showed a decrease in redundancy over the last two decades, which is not always linked with improvements in per capita food availability.

  5. Tension (re)builds: Biophysical mechanisms of embryonic wound repair.

    Science.gov (United States)

    Zulueta-Coarasa, Teresa; Fernandez-Gonzalez, Rodrigo

    2017-04-01

    Embryonic tissues display an outstanding ability to rapidly repair wounds. Epithelia, in particular, serve as protective layers that line internal organs and form the skin. Thus, maintenance of epithelial integrity is of utmost importance for animal survival, particularly at embryonic stages, when an immune system has not yet fully developed. Rapid embryonic repair of epithelial tissues is conserved across species, and involves the collective migration of the cells around the wound. The migratory cell behaviours associated with wound repair require the generation and transmission of mechanical forces, not only for the cells to move, but also to coordinate their movements. Here, we review the forces involved in embryonic wound repair. We discuss how different force-generating structures are assembled at the molecular level, and the mechanisms that maintain the balance between force-generating structures as wounds close. Finally, we describe the mechanisms that cells use to coordinate the generation of mechanical forces around the wound. Collective cell movements and their misregulation have been associated with defective tissue repair, developmental abnormalities and cancer metastasis. Thus, we propose that understanding the role of mechanical forces during embryonic wound closure will be crucial to develop therapeutic interventions that promote or prevent collective cell movements under pathological conditions. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Airborne S-Band SAR for Forest Biophysical Retrieval in Temperate Mixed Forests of the UK

    Directory of Open Access Journals (Sweden)

    Ramesh K. Ningthoujam

    2016-07-01

    Full Text Available Radar backscatter from forest canopies is related to forest cover, canopy structure and aboveground biomass (AGB. The S-band frequency (3.1–3.3 GHz lies between the longer L-band (1–2 GHz and the shorter C-band (5–6 GHz and has been insufficiently studied for forest applications due to limited data availability. In anticipation of the British built NovaSAR-S satellite mission, this study evaluates the benefits of polarimetric S-band SAR for forest biophysical properties. To understand the scattering mechanisms in forest canopies at S-band the Michigan Microwave Canopy Scattering (MIMICS-I radiative transfer model was used. S-band backscatter was found to have high sensitivity to the forest canopy characteristics across all polarisations and incidence angles. This sensitivity originates from ground/trunk interaction as the dominant scattering mechanism related to broadleaved species for co-polarised mode and specific incidence angles. The study was carried out in the temperate mixed forest at Savernake Forest and Wytham Woods in southern England, where airborne S-band SAR imagery and field data are available from the recent AirSAR campaign. Field data from the test sites revealed wide ranges of forest parameters, including average canopy height (6–23 m, diameter at breast-height (7–42 cm, basal area (0.2–56 m2/ha, stem density (20–350 trees/ha and woody biomass density (31–520 t/ha. S-band backscatter-biomass relationships suggest increasing backscatter sensitivity to forest AGB with least error between 90.63 and 99.39 t/ha and coefficient of determination (r2 between 0.42 and 0.47 for the co-polarised channel at 0.25 ha resolution. The conclusion is that S-band SAR data such as from NovaSAR-S is suitable for monitoring forest aboveground biomass less than 100 t/ha at 25 m resolution in low to medium incidence angle range.

  7. Insight into model mechanisms through automatic parameter fitting: a new methodological framework for model development.

    Science.gov (United States)

    Tøndel, Kristin; Niederer, Steven A; Land, Sander; Smith, Nicolas P

    2014-05-20

    Striking a balance between the degree of model complexity and parameter identifiability, while still producing biologically feasible simulations using modelling is a major challenge in computational biology. While these two elements of model development are closely coupled, parameter fitting from measured data and analysis of model mechanisms have traditionally been performed separately and sequentially. This process produces potential mismatches between model and data complexities that can compromise the ability of computational frameworks to reveal mechanistic insights or predict new behaviour. In this study we address this issue by presenting a generic framework for combined model parameterisation, comparison of model alternatives and analysis of model mechanisms. The presented methodology is based on a combination of multivariate metamodelling (statistical approximation of the input-output relationships of deterministic models) and a systematic zooming into biologically feasible regions of the parameter space by iterative generation of new experimental designs and look-up of simulations in the proximity of the measured data. The parameter fitting pipeline includes an implicit sensitivity analysis and analysis of parameter identifiability, making it suitable for testing hypotheses for model reduction. Using this approach, under-constrained model parameters, as well as the coupling between parameters within the model are identified. The methodology is demonstrated by refitting the parameters of a published model of cardiac cellular mechanics using a combination of measured data and synthetic data from an alternative model of the same system. Using this approach, reduced models with simplified expressions for the tropomyosin/crossbridge kinetics were found by identification of model components that can be omitted without affecting the fit to the parameterising data. Our analysis revealed that model parameters could be constrained to a standard deviation of on

  8. Closing the gasoline system

    International Nuclear Information System (INIS)

    Hutcheson, R.C.

    1992-01-01

    In this paper, a representative of the Oil Companies' European Organization for Environmental and Health Protection (CONCAWE), argues the advantages of closing the gasoline system. Because this decouples the product from the environment, health risks and environmental damage are reduced. It is also more effective than changing the composition of gasoline because it offers better cost effectiveness, energy efficiency and the minimization of carbon dioxide release into the environment. However it will take time and political will to change until all European vehicles are fitted with three way catalysts and carbon canisters: control systems to monitor such systems will also need to be set up. However CONCAWE still recommends its adoption. (UK)

  9. Closing the fuel cycle

    International Nuclear Information System (INIS)

    Wolfe, B.; Judson, B.F.

    1984-01-01

    The possibilities for closing the fuel cycle in today's nuclear climate in the US are compared with those envisioned in 1977. Reprocessing, the fast breeder reactor program, and the uranium supply are discussed. The conclusion drawn is that the nuclear world is less healthy and less stable than the one previously envisioned and that the major task before the international nuclear community is to develop technologies, institutions, and accepted procedures that will allow to economically provide the huge store of energy from reprocessing and the breeder that it appears the world will desperately need

  10. Biophysical Interactions within Step-Pool Mountain Streams Following Wildfire

    Science.gov (United States)

    Parker, A.; Chin, A.; O'Dowd, A. P.

    2014-12-01

    macroinvertebrates closely coincides with the physical destruction of the step-pool morphology. The role that step-pools play in enhancing the ecological quality of fluvial systems, therefore, provides a key focus for effective management and restoration of aquatic resources following wildfires.

  11. Biophysical basis of low-power-laser effects

    Science.gov (United States)

    Karu, Tiina I.

    1996-06-01

    Biological responses of cells to visible and near IR (laser) radiation occur due to physical and/or chemical changes in photoacceptor molecules, components of respiratory chains (cyt a/a3 in mitochondria). As a result of the photoexcitation of electronic states, the following physical and/or chemical changes can occur: alteration of redox properties and acceleration of electron transfer, changes in biochemical activity due to local transient heating of chromophores, one-electron auto-oxidation and O2- production, and photodynamic action and 1O2 production. Different reaction channels can be activated to achieve the photobiological macroeffect. The primary physical and/or chemical changes induced by light in photoacceptor molecules are followed by a cascade of biochemical reactions in the cell that do not need further light activation and occur in the dark (photosignal transduction and amplification chains). These actions are connected with changes in cellular homeostasis parameters. The crucial step here is thought to be an alteration of the cellular redox state: a shift towards oxidation is associated with stimulation of cellular vitality, and a shift towards reduction is linked to inhibition. Cells with a lower than normal pH, where the redox state is shifted in the reduced direction, are considered to be more sensitive to the stimulative action of light than those with the respective parameters being optimal or near optimal. This circumstance explains the possible variations in observed magnitudes of low-power laser effects. Light action on the redox state of a cell via the respiratory chain also explains the diversity of low-power laser effects. Beside explaining many controversies in the field of low-power laser effects (i.e., the diversity of effects, the variable magnitude or absence of effects in certain studies), the proposed redox-regulation mechanism may be a fundamental explanation for some clinical effects of irradiation, for example the positive

  12. Biophysical Properties of Irradiated Erythrocytes and Role of Antioxidants

    International Nuclear Information System (INIS)

    Eman Mohammed Elbakrawy, E.M.

    2010-01-01

    Irradiation of blood and blood components with gamma-irradiation is recommended for the inactivation of T-lymphocytes and prevention of transfusion-associated graft versus host diseases. The aim of the present work is to ensure that the currently applied irradiation dose 25 Gy is a safe dose based on the study of the electrical behavior, rheological properties, membrane solubilization, membrane hemolysis and scanning electron microscope of stored erythrocytes. In addition it aims to study the possibility of increasing the irradiation doses to 50 and 100 Gy. Moreover Alpha lipoic acid (a potent natural antioxidant) was added to the stored erythrocytes before irradiation for radioprotection. Irradiation of erythrocytes with 25 Gy did not show significant changes for the calculated dielectric parameters. However, increasing the irradiation doses resulted in significant decrease in the calculated dielectric parameters reflecting the damaging effects of radiation on the membrane structure. The obtained results showed that α lipoic acid can play an important role in minimizing the radiation-induced damage to the erythrocytes and conserve their electrical properties. There were non-significant changes in viscosity after exposure to 25 Gy, while a significant increase at 50 Gy and a significant decrease at 100 Gy were observed. The study found that α lipoic acid (ALA) resulted in non-significant change in viscosity after exposure to 50 Gy and 100 Gy. A significant increase in the yield stress was observed after exposure to 25 and 50 Gy while at 100 Gy, the yield stress showed a remarkable decrease. Addition of .-lipoic acid before irradiation resulted in non-significant changes in the yield stress at doses 25, 50, 100 Gy.The obtained results of the average membrane solubilization (D 50 ) and the average membrane hemolysis (H 50 ) showed non-significant change at 25 Gy; while an observable decrease was observed at 50 Gy and 100 Gy. The addition of lipoic acid did not

  13. Closed Strings From Nothing

    Energy Technology Data Exchange (ETDEWEB)

    Lawrence, Albion

    2001-07-25

    We study the physics of open strings in bosonic and type II string theories in the presence of unstable D-branes. When the potential energy of the open string tachyon is at its minimum, Sen has argued that only closed strings remain in the perturbative spectrum. We explore the scenario of Yi and of Bergman, Hori and Yi, who argue that the open string degrees of freedom are strongly coupled and disappear through confinement. We discuss arguments using open string field theory and worldsheet boundary RG flows, which seem to indicate otherwise. We then describe a solitonic excitation of the open string tachyon and gauge field with the charge and tension of a fundamental closed string. This requires a double scaling limit where the tachyon is taken to its minimal value and the electric field is taken to its maximum value. The resulting flux tube has an unconstrained spatial profile; and for large fundamental string charge, it appears to have light, weakly coupled open strings living in the core. We argue that the flux tube acquires a size or order {alpha}' through sigma model and string coupling effects; and we argue that confinement effects make the light degrees of freedom heavy and strongly interacting.

  14. Closed Strings From Nothing

    International Nuclear Information System (INIS)

    Lawrence, Albion

    2001-01-01

    We study the physics of open strings in bosonic and type II string theories in the presence of unstable D-branes. When the potential energy of the open string tachyon is at its minimum, Sen has argued that only closed strings remain in the perturbative spectrum. We explore the scenario of Yi and of Bergman, Hori and Yi, who argue that the open string degrees of freedom are strongly coupled and disappear through confinement. We discuss arguments using open string field theory and worldsheet boundary RG flows, which seem to indicate otherwise. We then describe a solitonic excitation of the open string tachyon and gauge field with the charge and tension of a fundamental closed string. This requires a double scaling limit where the tachyon is taken to its minimal value and the electric field is taken to its maximum value. The resulting flux tube has an unconstrained spatial profile; and for large fundamental string charge, it appears to have light, weakly coupled open strings living in the core. We argue that the flux tube acquires a size or order α' through sigma model and string coupling effects; and we argue that confinement effects make the light degrees of freedom heavy and strongly interacting

  15. Hemispherical photography to estimate biophysical variables of cotton

    Directory of Open Access Journals (Sweden)

    Ziany N. Brandão

    Full Text Available ABSTRACT The Leaf Area Index (LAI is a key parameter to evaluate the vegetation spectral response, estimating plant nutrition and water requirements. However, in large fields is difficult to obtain accurate data to LAI determination. Therefore, the objective of this study was the estimation of LAI, biomass and yield of irrigated cotton through digital hemispherical photography. The treatments consisted of four nitrogen doses (0, 90, 180 and 270 kg ha-1 and four phosphorus doses (0, 120, 240 and 360 kg ha-1. Digital hemispherical photographs were collected under similar sky brightness conditions at 60 and 75 days after emergence (DAE, performed by the Digital Plant Canopy Imager - CI-110® of CID Inc. Biomass and LAI measurements were made on the same dates. LAI was also determined by destructive and non-destructive methods through a leaf area integrator (LI-COR® -LI-3100C model, and by measurements based on the midrib length of all leaves, respectively. The results indicate that the hemispherical images were appropriate to estimate the LAI and biomass production of irrigated cotton, while for the estimation of yield, more research is needed to improve the method.

  16. Optomechanical parameter estimation

    International Nuclear Information System (INIS)

    Ang, Shan Zheng; Tsang, Mankei; Harris, Glen I; Bowen, Warwick P

    2013-01-01

    We propose a statistical framework for the problem of parameter estimation from a noisy optomechanical system. The Cramér–Rao lower bound on the estimation errors in the long-time limit is derived and compared with the errors of radiometer and expectation–maximization (EM) algorithms in the estimation of the force noise power. When applied to experimental data, the EM estimator is found to have the lowest error and follow the Cramér–Rao bound most closely. Our analytic results are envisioned to be valuable to optomechanical experiment design, while the EM algorithm, with its ability to estimate most of the system parameters, is envisioned to be useful for optomechanical sensing, atomic magnetometry and fundamental tests of quantum mechanics. (paper)

  17. Melatonin reverses the enhanced oxidative damage to membrane lipids and improves skin biophysical characteristics in former-smokers - A study in postmenopausal women.

    Science.gov (United States)

    Sagan, Dorota; Stepniak, Jan; Gesing, Adam; Lewinski, Andrzej; Karbownik-Lewinska, Malgorzata

    2017-12-23

    Protective antioxidative effects of melatonin have been repeatedly documented in experimental and clinical studies. One of the most spectacular exogenous prooxidative agents is cigarette smoking. The aim of the study was to evaluate the level of oxidative damage to membrane lipids (lipid peroxidation; LPO) in blood serum, and in epidermis exfoliated during microdermabrasion collected from former-smokers who were treated with melatonin. The study was performed in postmenopausal women. Ninety (90) female volunteers, aged 46-67 years, were enrolled. Two major groups, i.e. never-smokers (n=44) and former-smokers (n=46), were divided into: Control, melatonin topical skin application, Restructurer (containing antioxidants) topical skin application, and melatonin oral treatment. Microdermabrasion was performed at point '0', after 2 weeks, and after 4 weeks of treatment. The following parameters were measured: LPO in blood serum, LPO in epidermis exfoliated during microdermabrasion, and skin biophysical characteristics, such as sebum, moisture, elasticity, and pigmentation. Malondialdehyde+4-hydroxyalkenals level (LPO index) was measured spectrophotometrically. Melatonin oral treatment significantly reversed the increased serum LPO level in former-smokers already after 2 weeks of treatment. In a univariate regression model, LPO blood level constituted the only independent factor negatively associated with melatonin oral treatment. After 4 weeks of treatment, melatonin given orally increased skin sebum, moisture and elasticity levels, and melatonin applied topically increased sebum level. Exogenous melatonin reverses the enhanced oxidative damage to membrane lipids and improves skin biophysical characteristics in former-smokers.

  18. Science policy up close

    CERN Document Server

    Marburger, John H

    2015-01-01

    In a career that included tenures as president of Stony Brook University, director of Brookhaven National Laboratory, and science advisor to President George W. Bush, John Marburger (1941 2011) found himself on the front line of battles that pulled science ever deeper into the political arena. From nuclear power to global warming and stem cell research, science controversies, he discovered, are never just about science. Science Policy Up Close" presents Marburger s reflections on the challenges science administrators face in the twenty-first century. In each phase of public service Marburger came into contact with a new dimension of science policy. The Shoreham Commission exposed him to the problem of handling a volatile public controversy over nuclear power. The Superconducting Super Collider episode gave him insights into the collision between government requirements and scientists expectations and feelings of entitlement. The Directorship of Brookhaven taught him how to talk to the public about the risks ...

  19. Jealousy and Relationship Closeness

    Directory of Open Access Journals (Sweden)

    Mark Attridge

    2013-02-01

    Full Text Available This study confirmed a hypothesis from the Emotion-in-Relationships conceptual model, which predicts that greater interdependence between relationship partners—or closeness—creates the potential for jealousy. The study also sought to better define the positive side of romantic jealousy in addition to its more negative attributes. College students in premarital relationships (N = 229 completed a questionnaire, including 27 different measures and the Multidimensional Jealousy Scale. Select data were obtained from 122 cases at 3-month follow-up. Each jealousy scale was tested for associations with demographic (age, sex, and race, person (life satisfaction, loneliness, romantic attachment styles, love styles, and romantic beliefs, and relationship (affective, closeness, and social exchange theory constructs. Results clearly distinguished emotional/reactive jealousy as mostly “good” and cognitive/suspicious jealousy as “bad.” Behavioral jealousy was associated with few measures. Implications are discussed for the interdependence model of relationships and the transactional model of jealousy.

  20. Closed metal supports

    Energy Technology Data Exchange (ETDEWEB)

    Dolotov, N P; Afanas' yev, Yu V; Brednev, V A; Nuzhadikhin, A G; Tsiplakov, B V; Uskov, I T

    1980-08-30

    A closed metal support system that has a specific profile includes roof timber, ledger and roof timber. For convenience of transport, assembly, disassembly and repeated use during operation of an extraction powered system, the uprights in the central part are made sectional and are connected to one another by a hinge for folding into transport position. Longitudinal openings are made at the ends of the uprights in order to provide strength by creating flexibility in the hinged connections. The hinged connections of the sectional uprights have elastic gaskets. For convenience in folding the reinforcement, the ends of the uprights of the roof timber and ledger have the shape of a channel at junctions of their hinged connection.

  1. Nonrelativistic closed string theory

    International Nuclear Information System (INIS)

    Gomis, Jaume; Ooguri, Hirosi

    2001-01-01

    We construct a Galilean invariant nongravitational closed string theory whose excitations satisfy a nonrelativistic dispersion relation. This theory can be obtained by taking a consistent low energy limit of any of the conventional string theories, including the heterotic string. We give a finite first order worldsheet Hamiltonian for this theory and show that this string theory has a sensible perturbative expansion, interesting high energy behavior of scattering amplitudes and a Hagedorn transition of the thermal ensemble. The strong coupling duals of the Galilean superstring theories are considered and are shown to be described by an eleven-dimensional Galilean invariant theory of light membrane fluctuations. A new class of Galilean invariant nongravitational theories of light-brane excitations are obtained. We exhibit dual formulations of the strong coupling limits of these Galilean invariant theories and show that they exhibit many of the conventional dualities of M theory in a nonrelativistic setting

  2. Closing the gap

    International Nuclear Information System (INIS)

    Moxon, Suzanne

    1999-01-01

    The problem of fish going through turbines at hydroelectric power plants and the growing concern over the survival rate of salmon at the US Army Corps operated Bonneville lock and dam on the Columbia river in the Pacific Northwest is discussed. The protection of the fish, the assessment of the hazards facing fish passing through turbines, the development of a new turbine, and improved turbine efficiency that reduces cavitation, turbulence and shear flow are examined. The closing of the gap between the turbine blades, hub and discharge ring to increase efficiency and reduce the risk to fish, and the development of the minimum gap runner (MGR) are described, and the lower maximum permitted power output of MGR is noted. (UK)

  3. Physiological parameters

    International Nuclear Information System (INIS)

    Natera, E.S.

    1998-01-01

    The physiological characteristics of man depend on the intake, metabolism and excretion of stable elements from food, water, and air. The physiological behavior of natural radionuclides and radionuclides from nuclear weapons testing and from the utilization of nuclear energy is believed to follow the pattern of stable elements. Hence information on the normal physiological processes occurring in the human body plays an important role in the assessment of the radiation dose received by man. Two important physiological parameters needed for internal dose determination are the pulmonary function and the water balance. In the Coordinated Research Programme on the characterization of Asian population, five participants submitted data on these physiological characteristics - China, India, Japan, Philippines and Viet Nam. During the CRP, data on other pertinent characteristics such as physical and dietary were simultaneously being collected. Hence, the information on the physiological characteristics alone, coming from the five participants were not complete and are probably not sufficient to establish standard values for the Reference Asian Man. Nonetheless, the data collected is a valuable contribution to this research programme

  4. A Biophysical Model of CRISPR/Cas9 Activity for Rational Design of Genome Editing and Gene Regulation

    Science.gov (United States)

    Farasat, Iman; Salis, Howard M.

    2016-01-01

    The ability to precisely modify genomes and regulate specific genes will greatly accelerate several medical and engineering applications. The CRISPR/Cas9 (Type II) system binds and cuts DNA using guide RNAs, though the variables that control its on-target and off-target activity remain poorly characterized. Here, we develop and parameterize a system-wide biophysical model of Cas9-based genome editing and gene regulation to predict how changing guide RNA sequences, DNA superhelical densities, Cas9 and crRNA expression levels, organisms and growth conditions, and experimental conditions collectively control the dynamics of dCas9-based binding and Cas9-based cleavage at all DNA sites with both canonical and non-canonical PAMs. We combine statistical thermodynamics and kinetics to model Cas9:crRNA complex formation, diffusion, site selection, reversible R-loop formation, and cleavage, using large amounts of structural, biochemical, expression, and next-generation sequencing data to determine kinetic parameters and develop free energy models. Our results identify DNA supercoiling as a novel mechanism controlling Cas9 binding. Using the model, we predict Cas9 off-target binding frequencies across the lambdaphage and human genomes, and explain why Cas9’s off-target activity can be so high. With this improved understanding, we propose several rules for designing experiments for minimizing off-target activity. We also discuss the implications for engineering dCas9-based genetic circuits. PMID:26824432

  5. Radiation dose responses for chemoradiation therapy of pancreatic cancer: an analysis of compiled clinical data using biophysical models.

    Science.gov (United States)

    Moraru, Ion C; Tai, An; Erickson, Beth; Li, X Allen

    2014-01-01

    We analyzed recent clinical data obtained from chemoradiation of unresectable, locally advanced pancreatic cancer (LAPC) in order to examine possible benefits from radiation therapy dose escalation. A modified linear quadratic model was used to fit clinical tumor response and survival data of chemoradiation treatments for LAPC reported from 20 institutions. Biophysical radiosensitivity parameters were extracted from the fits. Examination of the clinical data demonstrated an enhancement in tumor response with higher irradiation dose, an important clinical result for palliation and quality of life. Little indication of improvement in 1-year survival with increased radiation dose was observed. Possible dose escalation schemes are proposed based on calculations of the biologically effective dose required for a 50% tumor response rate. Based on the evaluation of tumor response data, the escalation of radiation dose presents potential clinical benefits which when combined with normal tissue complication analyses may result in improved treatment outcome for locally advanced pancreatic cancer patients. Copyright © 2014 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.

  6. Chiropractic biophysics technique: a linear algebra approach to posture in chiropractic.

    Science.gov (United States)

    Harrison, D D; Janik, T J; Harrison, G R; Troyanovich, S; Harrison, D E; Harrison, S O

    1996-10-01

    This paper discusses linear algebra as applied to human posture in chiropractic, specifically chiropractic biophysics technique (CBP). Rotations, reflections and translations are geometric functions studied in vector spaces in linear algebra. These mathematical functions are termed rigid body transformations and are applied to segmental spinal movement in the literature. Review of the literature indicates that these linear algebra concepts have been used to describe vertebral motion. However, these rigid body movers are presented here as applying to the global postural movements of the head, thoracic cage and pelvis. The unique inverse functions of rotations, reflections and translations provide a theoretical basis for making postural corrections in neutral static resting posture. Chiropractic biophysics technique (CBP) uses these concepts in examination procedures, manual spinal manipulation, instrument assisted spinal manipulation, postural exercises, extension traction and clinical outcome measures.

  7. Ground-and satellite-based evidence of the biophysical mechanisms behind the greening Sahel

    DEFF Research Database (Denmark)

    Brandt, Martin Stefan; Mbow, Cheikh; Diouf, Abdoul A.

    2015-01-01

    After a dry period with prolonged droughts in the 1970s and 1980s, recent scientific outcome suggests that the decades of abnormally dry conditions in the Sahel have been reversed by positive anomalies in rainfall. Various remote sensing studies observed a positive trend in vegetation greenness...... over the last decades which is known as the re-greening of the Sahel. However, little investment has been made in including long-term ground-based data collections to evaluate and better understand the biophysical mechanisms behind these findings. Thus, deductions on a possible increment in biomass...... remain speculative. Our aim is to bridge these gaps and give specifics on the biophysical background factors of the re-greening Sahel. Therefore, a trend analysis was applied on long time series (1987-2013) of satellite-based vegetation and rainfall data, as well as on ground-observations of leaf biomass...

  8. Biophysics of skin and its treatments structural, nanotribological, and nanomechanical studies

    CERN Document Server

    Bhushan, Bharat

    2017-01-01

    This book provides a comprehensive overview of the structural, nanotribological and nanomechanical properties of skin with and without cream treatment as a function of operating environment. The biophysics of skin as the outer layer covering human or animal body is discussed as a complex biological structure. Skin cream is used to improve skin health and create a smooth, soft, and flexible surface with moist perception by altering the surface roughness, friction, adhesion, elastic modulus, and surface charge of the skin surface. .

  9. Materials science and biophysics applications at the ISOLDE radioactive ion beam facility

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, U., E-mail: uwahl@itn.pt [Instituto Tecnologico e Nuclear, Estrada Nacional 10, 2686-953 Sacavem (Portugal); Centro de Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto 2, 1649-003 Lisboa (Portugal)

    2011-12-15

    The ISOLDE isotope separator facility at CERN provides a variety of radioactive ion beams, currently more than 800 different isotopes from {approx}70 chemical elements. The radioisotopes are produced on-line by nuclear reactions from a 1.4 GeV proton beam with various types of targets, outdiffusion of the reaction products and, if possible, chemically selective ionisation, followed by 60 kV acceleration and mass separation. While ISOLDE is mainly used for nuclear and atomic physics studies, applications in materials science and biophysics account for a significant part (currently {approx}15%) of the delivered beam time, requested by 18 different experiments. The ISOLDE materials science and biophysics community currently consists of {approx}80 scientists from more than 40 participating institutes and 21 countries. In the field of materials science, investigations focus on the study of semiconductors and oxides, with the recent additions of nanoparticles and metals, while the biophysics studies address the toxicity of metal ions in biological systems. The characterisation methods used are typical radioactive probe techniques such as Moessbauer spectroscopy, perturbed angular correlation, emission channeling, and tracer diffusion studies. In addition to these 'classic' methods of nuclear solid state physics, also standard semiconductor analysis techniques such as photoluminescence or deep level transient spectroscopy profit from the application of radioactive isotopes, which helps them to overcome their chemical 'blindness' since the nuclear half life of radioisotopes provides a signal that changes in time with characteristic exponential decay or saturation curves. In this presentation an overview will be given on the recent research activities in materials science and biophysics at ISOLDE, presenting some of the highlights during the last five years, together with a short outlook on the new developments under way.

  10. Coexistence between silent and bursting states in a biophysical Hodgkin-Huxley-type of model

    DEFF Research Database (Denmark)

    Stankevich, Nataliya; Mosekilde, Erik

    2017-01-01

    in a slightly modified, biophysical model that describe the dynamics of pancreatic beta-cells. To realize this form of coexistence, we have introduced an additional voltage-dependent potassium current that is activated in the region around the original, unstable equilibrium point. It is interesting to note...... that this modification also leads the model to display a blue-sky catastrophe in the transition region between chaotic and bursting states....

  11. Enhancing the biophysical properties of mRFP1 through incorporation of fluoroproline

    Energy Technology Data Exchange (ETDEWEB)

    Deepankumar, Kanagavel; Nadarajan, Saravanan Prabhu; Ayyadurai, Niraikulam; Yun, Hyungdon, E-mail: hyungdon@ynu.ac.kr

    2013-11-01

    Graphical abstract: Enhancing the biophysical properties of mRFP1 through incorporation of (2S, 4R)-4-fluoroproline at proline residues after mutating non-permissive site Pro63 into Ala. -- Highlights: •We incorporate (4S)-FP into mRFP1 led to insoluble protein. •Whereas, incorporation of (4R)-FP resulted in soluble but lost its fluorescence. •mRFP1-P63A mutant accommodate (4R)-FP and gave soluble protein with fluorescence. •Moreover mRFP1-P63A[(4R)-FP] showed enhanced biophysical properties of protein. -- Abstract: Here we enhanced the stability and biophysical properties of mRFP1 through a combination of canonical and non-canonical amino acid mutagenesis. The global replacement of proline residue with (2S, 4R)-4-fluoroproline [(4R)-FP] into mRFP1 led to soluble protein but lost its fluorescence, whereas (2S, 4S)-4-fluoroproline [(4S)-FP] incorporation resulted in insoluble protein. The bioinformatics analysis revealed that (4R)-FP incorporation at Pro63 caused fluorescence loss due to the steric hindrance of fluorine atom of (4R)-FP with the chromophore. Therefore, Pro63 residue was mutated with the smallest amino acid Ala to maintain non coplanar conformation of the chromophore and helps to retain its fluorescence with (4R)-FP incorporation. The incorporation of (4R)-FP into mRFP1-P63A showed about 2–3-fold enhancement in thermal and chemical stability. The rate of maturation is also greatly accelerated over the presence of (4R)-FP into mRFP1-P63A. Our study showed that a successful enhancement in the biophysical property of mRFP1-P63A[(4R)-FP] using non-canonical amino acid mutagenesis after mutating non-permissive site Pro63 into Ala.

  12. Enhancing the biophysical properties of mRFP1 through incorporation of fluoroproline

    International Nuclear Information System (INIS)

    Deepankumar, Kanagavel; Nadarajan, Saravanan Prabhu; Ayyadurai, Niraikulam; Yun, Hyungdon

    2013-01-01

    Graphical abstract: Enhancing the biophysical properties of mRFP1 through incorporation of (2S, 4R)-4-fluoroproline at proline residues after mutating non-permissive site Pro63 into Ala. -- Highlights: •We incorporate (4S)-FP into mRFP1 led to insoluble protein. •Whereas, incorporation of (4R)-FP resulted in soluble but lost its fluorescence. •mRFP1-P63A mutant accommodate (4R)-FP and gave soluble protein with fluorescence. •Moreover mRFP1-P63A[(4R)-FP] showed enhanced biophysical properties of protein. -- Abstract: Here we enhanced the stability and biophysical properties of mRFP1 through a combination of canonical and non-canonical amino acid mutagenesis. The global replacement of proline residue with (2S, 4R)-4-fluoroproline [(4R)-FP] into mRFP1 led to soluble protein but lost its fluorescence, whereas (2S, 4S)-4-fluoroproline [(4S)-FP] incorporation resulted in insoluble protein. The bioinformatics analysis revealed that (4R)-FP incorporation at Pro63 caused fluorescence loss due to the steric hindrance of fluorine atom of (4R)-FP with the chromophore. Therefore, Pro63 residue was mutated with the smallest amino acid Ala to maintain non coplanar conformation of the chromophore and helps to retain its fluorescence with (4R)-FP incorporation. The incorporation of (4R)-FP into mRFP1-P63A showed about 2–3-fold enhancement in thermal and chemical stability. The rate of maturation is also greatly accelerated over the presence of (4R)-FP into mRFP1-P63A. Our study showed that a successful enhancement in the biophysical property of mRFP1-P63A[(4R)-FP] using non-canonical amino acid mutagenesis after mutating non-permissive site Pro63 into Ala

  13. Polish Academy of Sciences. Institute of Biochemistry and Biophysics. Research Report 1998-1999

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    The report presented research activities of the Institute of Biochemistry and Biophysics, Polish Academy of Sciences, in 1998-1999. Research interests focus on: replication, mutagenesis and repair of DNA, regulation of gene expression, biosynthesis and post-translational modifications of proteins, gene sequencing and functional gene analysis, structure and function of enzymes, conformation of proteins and peptides, modeling of structures and prediction of function of proteins.

  14. Polish Academy of Sciences. Institute of Biochemistry and Biophysics. Research Report 1998-1999

    International Nuclear Information System (INIS)

    2000-01-01

    The report presented research activities of the Institute of Biochemistry and Biophysics, Polish Academy of Sciences, in 1998-1999. Research interests focus on: replication, mutagenesis and repair of DNA, regulation of gene expression, biosynthesis and post-translational modifications of proteins, gene sequencing and functional gene analysis, structure and function of enzymes, conformation of proteins and peptides, modeling of structures and prediction of function of proteins

  15. Biophysical Assessment of Single Cell Cytotoxicity: Diesel Exhaust Particle-Treated Human Aortic Endothelial Cells

    OpenAIRE

    Wu, Yangzhe; Yu, Tian; Gilbertson, Timothy A.; Zhou, Anhong; Xu, Hao; Nguyen, Kytai Truong

    2012-01-01

    Exposure to diesel exhaust particles (DEPs), a major source of traffic-related air pollution, has become a serious health concern due to its adverse influences on human health including cardiovascular and respiratory disorders. To elucidate the relationship between biophysical properties (cell topography, cytoskeleton organizations, and cell mechanics) and functions of endothelial cells exposed to DEPs, atomic force microscope (AFM) was applied to analyze the toxic effects of DEPs on a model ...

  16. Biochemical and Biophysical Cues in Matrix Design for Chronic and Diabetic Wound Treatment

    OpenAIRE

    Xiao, Yun; Ahadian, Samad; Radisic, Milica

    2017-01-01

    Progress in biomaterial science and engineering and increasing knowledge in cell biology have enabled us to develop functional biomaterials providing appropriate biochemical and biophysical cues for tissue regeneration applications. Tissue regeneration is particularly important to treat chronic wounds of people with diabetes. Understanding and controlling the cellular microenvironment of the wound tissue are important to improve the wound healing process. In this study, we review different bi...

  17. Interplay of mycolic acids, antimycobacterial compounds and pulmonary surfactant membrane: a biophysical approach to disease.

    Science.gov (United States)

    Pinheiro, Marina; Giner-Casares, Juan J; Lúcio, Marlene; Caio, João M; Moiteiro, Cristina; Lima, José L F C; Reis, Salette; Camacho, Luis

    2013-02-01

    This work focuses on the interaction of mycolic acids (MAs) and two antimycobacterial compounds (Rifabutin and N'-acetyl-Rifabutin) at the pulmonary membrane level to convey a biophysical perspective of their role in disease. For this purpose, accurate biophysical techniques (Langmuir isotherms, Brewster angle microscopy, and polarization-modulation infrared reflection spectroscopy) and lipid model systems were used to mimic biomembranes: MAs mimic bacterial lipids of the Mycobacterium tuberculosis (MTb) membrane, whereas Curosurf® was used as the human pulmonary surfactant (PS) membrane model. The results obtained show that high quantities of MAs are responsible for significant changes on PS biophysical properties. At the dynamic inspiratory surface tension, high amounts of MAs decrease the order of the lipid monolayer, which appears to be a concentration dependent effect. These results suggest that the amount of MAs might play a critical role in the initial access of the bacteria to their targets. Both molecules also interact with the PS monolayer at the dynamic inspiratory surface. However, in the presence of higher amounts of MAs, both compounds improve the phospholipid packing and, therefore, the order of the lipid surfactant monolayer. In summary, this work discloses the putative protective effects of antimycobacterial compounds against the MAs induced biophysical impairment of PS lipid monolayers. These protective effects are most of the times overlooked, but can constitute an additional therapeutic value in the treatment of pulmonary tuberculosis (Tb) and may provide significant insights for the design of new and more efficient anti-Tb drugs based on their behavior as membrane ordering agents. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Modeling the effects of noninvasive transcranial brain stimulation at the biophysical, network, and cognitive Level

    DEFF Research Database (Denmark)

    Hartwigsen, Gesa; Bergmann, Til Ole; Herz, Damian Marc

    2015-01-01

    these approaches advance the scientific potential of NTBS as an interventional tool in cognitive neuroscience. (i) Leveraging the anatomical information provided by structural imaging, the electric field distribution in the brain can be modeled and simulated. Biophysical modeling approaches generate testable...... predictions regarding the impact of interindividual variations in cortical anatomy on the injected electric fields or the influence of the orientation of current flow on the physiological stimulation effects. (ii) Functional brain mapping of the spatiotemporal neural dynamics during cognitive tasks can...

  19. Combining Biophysical and Price Simulations to Assess the Economics of Long-Term Crop Rotations

    OpenAIRE

    Murray-Prior, Roy B.; Whish, J.; Carberry, Peter S.; Dalgleish, N.

    2003-01-01

    Biophysical simulation models (e.g. APSIM) using historical rainfall data are increasingly being used to provide yield and other data on crop rotations in various regions of Australia. However, to analyse the economics of these rotations it is desirable to incorporate the other main driver of profitability, price variation. Because the context was that APSIM was being used to simulate an existing trial site being monitored by a farmer group Gross Margin output was considered most appropriate....

  20. Biophysical and sociocultural factors underlying spatial trade-offs of ecosystem services in semiarid watersheds

    Directory of Open Access Journals (Sweden)

    Marina García-Llorente

    2015-09-01

    Full Text Available Biophysical and social systems are linked to form social-ecological systems whose sustainability depends on their capacity to absorb uncertainty and cope with disturbances. In this study, we explored the key biophysical and socio-cultural factors underlying ecosystem service supply in two semiarid watersheds of southern Spain. These included variables associated with the role that freshwater flows and biodiversity play in securing the system's capacity to sustain essential ecosystem services and their relationship with social demand for services, local water governance, and land-use intensification. Our results reveal the importance of considering the invisible dimensions of water and biodiversity, i.e. green freshwater flows and trait-based indicators, because of their relevance to the supply of ecosystem services. Furthermore, they uncover the importance of traditional irrigation canals, a local water governance system, in maintaining the ecosystems' capacity to supply services. The study also highlights the complex trade-offs that occur because of the spatial mismatch between ecosystem service supply (upstream and ecosystem service demand (downstream in watersheds. Finally, we found that land-use intensification generally resulted in losses of the biophysical factors that underpin the supply of some ecosystem services, increases in social demand for less diversified services, and the abandonment of local governance practices. Attempts to manage social-ecological systems toward sustainability at the local scale should identify the key biophysical and socio-cultural factors that are essential for maintaining ecosystem services and should recognize existing interrelationships between them. Land-use management should also take into account ecosystem service trade-offs and the consequences resulting from land-use intensification.

  1. A biotic video game smart phone kit for formal and informal biophysics education

    Science.gov (United States)

    Kim, Honesty; Lee, Seung Ah; Riedel-Kruse, Ingmar

    2015-03-01

    Novel ways for formal and informal biophysics education are important. We present a low-cost biotic game design kit that incorporates microbial organisms into an interactive gaming experience: A 3D-printable microscope containing four LEDs controlled by a joystick enable human players to provide directional light stimuli to the motile single-celled organism Euglena gracilis. These cellular behaviors are displayed on the integrated smart phone. Real time cell-tracking couples these cells into interactive biotic video game play, i.e., the human player steers Euglena to play soccer with virtual balls and goals. The player's learning curve in mastering this fun game is intrinsically coupled to develop a deeper knowledge about Euglena's cell morphology and the biophysics of its phototactic behavior. This kit is dual educational - via construction and via play - and it provides an engaging theme for a formal biophysics devices class as well as to be presented in informal outreach activities; its low cost and open soft- and hardware should enable wide adoption.

  2. Final report for Conference Support Grant "From Computational Biophysics to Systems Biology - CBSB12"

    Energy Technology Data Exchange (ETDEWEB)

    Hansmann, Ulrich H.E.

    2012-07-02

    This report summarizes the outcome of the international workshop From Computational Biophysics to Systems Biology (CBSB12) which was held June 3-5, 2012, at the University of Tennessee Conference Center in Knoxville, TN, and supported by DOE through the Conference Support Grant 120174. The purpose of CBSB12 was to provide a forum for the interaction between a data-mining interested systems biology community and a simulation and first-principle oriented computational biophysics/biochemistry community. CBSB12 was the sixth in a series of workshops of the same name organized in recent years, and the second that has been held in the USA. As in previous years, it gave researchers from physics, biology, and computer science an opportunity to acquaint each other with current trends in computational biophysics and systems biology, to explore venues of cooperation, and to establish together a detailed understanding of cells at a molecular level. The conference grant of $10,000 was used to cover registration fees and provide travel fellowships to selected students and postdoctoral scientists. By educating graduate students and providing a forum for young scientists to perform research into the working of cells at a molecular level, the workshop adds to DOE's mission of paving the way to exploit the abilities of living systems to capture, store and utilize energy.

  3. BIOPHYSICAL PROPERTIES OF NUCLEIC ACIDS AT SURFACES RELEVANT TO MICROARRAY PERFORMANCE.

    Science.gov (United States)

    Rao, Archana N; Grainger, David W

    2014-04-01

    Both clinical and analytical metrics produced by microarray-based assay technology have recognized problems in reproducibility, reliability and analytical sensitivity. These issues are often attributed to poor understanding and control of nucleic acid behaviors and properties at solid-liquid interfaces. Nucleic acid hybridization, central to DNA and RNA microarray formats, depends on the properties and behaviors of single strand (ss) nucleic acids (e.g., probe oligomeric DNA) bound to surfaces. ssDNA's persistence length, radius of gyration, electrostatics, conformations on different surfaces and under various assay conditions, its chain flexibility and curvature, charging effects in ionic solutions, and fluorescent labeling all influence its physical chemistry and hybridization under assay conditions. Nucleic acid (e.g., both RNA and DNA) target interactions with immobilized ssDNA strands are highly impacted by these biophysical states. Furthermore, the kinetics, thermodynamics, and enthalpic and entropic contributions to DNA hybridization reflect global probe/target structures and interaction dynamics. Here we review several biophysical issues relevant to oligomeric nucleic acid molecular behaviors at surfaces and their influences on duplex formation that influence microarray assay performance. Correlation of biophysical aspects of single and double-stranded nucleic acids with their complexes in bulk solution is common. Such analysis at surfaces is not commonly reported, despite its importance to microarray assays. We seek to provide further insight into nucleic acid-surface challenges facing microarray diagnostic formats that have hindered their clinical adoption and compromise their research quality and value as genomics tools.

  4. Progress and challenges of engineering a biophysical CO2-concentrating mechanism into higher plants.

    Science.gov (United States)

    Rae, Benjamin D; Long, Benedict M; Förster, Britta; Nguyen, Nghiem D; Velanis, Christos N; Atkinson, Nicky; Hee, Wei Yih; Mukherjee, Bratati; Price, G Dean; McCormick, Alistair J

    2017-06-01

    Growth and productivity in important crop plants is limited by the inefficiencies of the C3 photosynthetic pathway. Introducing CO2-concentrating mechanisms (CCMs) into C3 plants could overcome these limitations and lead to increased yields. Many unicellular microautotrophs, such as cyanobacteria and green algae, possess highly efficient biophysical CCMs that increase CO2 concentrations around the primary carboxylase enzyme, Rubisco, to enhance CO2 assimilation rates. Algal and cyanobacterial CCMs utilize distinct molecular components, but share several functional commonalities. Here we outline the recent progress and current challenges of engineering biophysical CCMs into C3 plants. We review the predicted requirements for a functional biophysical CCM based on current knowledge of cyanobacterial and algal CCMs, the molecular engineering tools and research pipelines required to translate our theoretical knowledge into practice, and the current challenges to achieving these goals. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  5. BIOPHYSICAL PROPERTIES OF NUCLEIC ACIDS AT SURFACES RELEVANT TO MICROARRAY PERFORMANCE

    Science.gov (United States)

    Rao, Archana N.; Grainger, David W.

    2014-01-01

    Both clinical and analytical metrics produced by microarray-based assay technology have recognized problems in reproducibility, reliability and analytical sensitivity. These issues are often attributed to poor understanding and control of nucleic acid behaviors and properties at solid-liquid interfaces. Nucleic acid hybridization, central to DNA and RNA microarray formats, depends on the properties and behaviors of single strand (ss) nucleic acids (e.g., probe oligomeric DNA) bound to surfaces. ssDNA’s persistence length, radius of gyration, electrostatics, conformations on different surfaces and under various assay conditions, its chain flexibility and curvature, charging effects in ionic solutions, and fluorescent labeling all influence its physical chemistry and hybridization under assay conditions. Nucleic acid (e.g., both RNA and DNA) target interactions with immobilized ssDNA strands are highly impacted by these biophysical states. Furthermore, the kinetics, thermodynamics, and enthalpic and entropic contributions to DNA hybridization reflect global probe/target structures and interaction dynamics. Here we review several biophysical issues relevant to oligomeric nucleic acid molecular behaviors at surfaces and their influences on duplex formation that influence microarray assay performance. Correlation of biophysical aspects of single and double-stranded nucleic acids with their complexes in bulk solution is common. Such analysis at surfaces is not commonly reported, despite its importance to microarray assays. We seek to provide further insight into nucleic acid-surface challenges facing microarray diagnostic formats that have hindered their clinical adoption and compromise their research quality and value as genomics tools. PMID:24765522

  6. Quantifying Vegetation Biophysical Variables from Imaging Spectroscopy Data: A Review on Retrieval Methods

    Science.gov (United States)

    Verrelst, Jochem; Malenovský, Zbyněk; Van der Tol, Christiaan; Camps-Valls, Gustau; Gastellu-Etchegorry, Jean-Philippe; Lewis, Philip; North, Peter; Moreno, Jose

    2018-06-01

    An unprecedented spectroscopic data stream will soon become available with forthcoming Earth-observing satellite missions equipped with imaging spectroradiometers. This data stream will open up a vast array of opportunities to quantify a diversity of biochemical and structural vegetation properties. The processing requirements for such large data streams require reliable retrieval techniques enabling the spatiotemporally explicit quantification of biophysical variables. With the aim of preparing for this new era of Earth observation, this review summarizes the state-of-the-art retrieval methods that have been applied in experimental imaging spectroscopy studies inferring all kinds of vegetation biophysical variables. Identified retrieval methods are categorized into: (1) parametric regression, including vegetation indices, shape indices and spectral transformations; (2) nonparametric regression, including linear and nonlinear machine learning regression algorithms; (3) physically based, including inversion of radiative transfer models (RTMs) using numerical optimization and look-up table approaches; and (4) hybrid regression methods, which combine RTM simulations with machine learning regression methods. For each of these categories, an overview of widely applied methods with application to mapping vegetation properties is given. In view of processing imaging spectroscopy data, a critical aspect involves the challenge of dealing with spectral multicollinearity. The ability to provide robust estimates, retrieval uncertainties and acceptable retrieval processing speed are other important aspects in view of operational processing. Recommendations towards new-generation spectroscopy-based processing chains for operational production of biophysical variables are given.

  7. Human Pluripotent Stem Cell Mechanobiology: Manipulating the Biophysical Microenvironment for Regenerative Medicine and Tissue Engineering Applications.

    Science.gov (United States)

    Ireland, Ronald G; Simmons, Craig A

    2015-11-01

    A stem cell in its microenvironment is subjected to a myriad of soluble chemical cues and mechanical forces that act in concert to orchestrate cell fate. Intuitively, many of these soluble and biophysical factors have been the focus of intense study to successfully influence and direct cell differentiation in vitro. Human pluripotent stem cells (hPSCs) have been of considerable interest in these studies due to their great promise for regenerative medicine. Culturing and directing differentiation of hPSCs, however, is currently extremely labor-intensive and lacks the efficiency required to generate large populations of clinical-grade cells. Improved efficiency may come from efforts to understand how the cell biophysical signals can complement biochemical signals to regulate cell pluripotency and direct differentiation. In this concise review, we explore hPSC mechanobiology and how the hPSC biophysical microenvironment can be manipulated to maintain and differentiate hPSCs into functional cell types for regenerative medicine and tissue engineering applications. © 2015 AlphaMed Press.

  8. Assessment of the biophysical impacts of utility-scale photovoltaics through observations and modelling

    Science.gov (United States)

    Broadbent, A. M.; Georgescu, M.; Krayenhoff, E. S.; Sailor, D.

    2017-12-01

    Utility-scale solar power plants are a rapidly growing component of the solar energy sector. Utility-scale photovoltaic (PV) solar power generation in the United States has increased by 867% since 2012 (EIA, 2016). This expansion is likely to continue as the cost PV technologies decrease. While most agree that solar power can decrease greenhouse gas emissions, the biophysical effects of PV systems on surface energy balance (SEB), and implications for surface climate, are not well understood. To our knowledge, there has never been a detailed observational study of SEB at a utility-scale solar array. This study presents data from an eddy covariance observational tower, temporarily placed above a utility-scale PV array in Southern Arizona. Comparison of PV SEB with a reference (unmodified) site, shows that solar panels can alter the SEB and near surface climate. SEB observations are used to develop and validate a new and more complete SEB PV model. In addition, the PV model is compared to simpler PV modelling methods. The simpler PV models produce differing results to our newly developed model and cannot capture the more complex processes that influence PV SEB. Finally, hypothetical scenarios of PV expansion across the continental United States (CONUS) were developed using various spatial mapping criteria. CONUS simulations of PV expansion reveal regional variability in biophysical effects of PV expansion. The study presents the first rigorous and validated simulations of the biophysical effects of utility-scale PV arrays.

  9. Measuring Visual Closeness of 3-D Models

    KAUST Repository

    Gollaz Morales, Jose Alejandro

    2012-09-01

    Measuring visual closeness of 3-D models is an important issue for different problems and there is still no standardized metric or algorithm to do it. The normal of a surface plays a vital role in the shading of a 3-D object. Motivated by this, we developed two applications to measure visualcloseness, introducing normal difference as a parameter in a weighted metric in Metro’s sampling approach to obtain the maximum and mean distance between 3-D models using 3-D and 6-D correspondence search structures. A visual closeness metric should provide accurate information on what the human observers would perceive as visually close objects. We performed a validation study with a group of people to evaluate the correlation of our metrics with subjective perception. The results were positive since the metrics predicted the subjective rankings more accurately than the Hausdorff distance.

  10. Closing the fuel cycle

    International Nuclear Information System (INIS)

    Aycoberry, C.; Rougeau, J.P.

    1987-01-01

    The progressive implementation of some key nuclear fuel cycle capecities in a country corresponds to a strategy for the acquisition of an independant energy source, France, Japan, and some European countries are engaged in such strategic programs. In France, COGEMA, the nuclear fuel company, has now completed the industrial demonstration of the closed fuel cycle. Its experience covers every step of the front-end and of the back-end: transportation of spent fuels, storage, reprocessing, wastes conditioning. The La Hague reprocessing plant smooth operation, as well as the large investment program under active progress can testify of full mastering of this industry. Together with other French and European companies, COGEMA is engaged in the recycling industry, both for uranium through conversion of uranyl nitrate for its further reeichment, and for plutonium through MOX fuel fabrication. Reprocessing and recycling offer the optimum solution for a complete, economic, safe and future-oriented fuel cycle, hence contributing to the necessary development of nuclear energy. (author)

  11. The closed fuel cycle

    International Nuclear Information System (INIS)

    Froment, Antoine; Gillet, Philippe

    2007-01-01

    Available in abstract form only. Full text of publication follows: The fast growth of the world's economy coupled with the need for optimizing use of natural resources, for energy security and for climate change mitigation make energy supply one of the 21. century most daring challenges. The high reliability and efficiency of nuclear energy, its competitiveness in an energy market undergoing a new oil shock are as many factors in favor of the 'renaissance' of this greenhouse gas free energy. Over 160,000 tHM of LWR1 and AGR2 Used Nuclear Fuel (UNF) have already been unloaded from the reactor cores corresponding to 7,000 tons discharged per year worldwide. By 2030, this amount could exceed 400,000 tHM and annual unloading 14,000 tHM/year. AREVA believes that closing the nuclear fuel cycle through the treatment and recycling of Used Nuclear Fuel sustains the worldwide nuclear power expansion. It is an economically sound and environmentally responsible choice, based on the preservation of natural resources through the recycling of used fuel. It furthermore provides a safe and secure management of wastes while significantly minimizing the burden left to future generations. (authors)

  12. Close-range photogrammetry for aircraft quality control

    Science.gov (United States)

    Schwartz, D. S.

    Close range photogrammetry is applicable to quality assurance inspections, design data acquisition, and test management support tasks, yielding significant cost avoidance and increased productivity. An understanding of mensuration parameters and their related accuracies is fundamental to the successful application of industrial close range photogrammetry. Attention is presently given to these parameters and to the use of computer modelling as an aid to the photogrammetric entrepreneur in industry. Suggested improvements to cameras and film readers for industrial applications are discussed.

  13. Epigenetic Modulation of the Biophysical Properties of Drug-Resistant Cell Lipids to Restore Drug Transport and Endocytic Functions

    OpenAIRE

    Vijayaraghavalu, Sivakumar; Peetla, Chiranjeevi; Lu, Shan; Labhasetwar, Vinod

    2012-01-01

    In our recent studies exploring the biophysical characteristics of resistant cell lipids, and the role they play in drug transport, we demonstrated the difference of drug-resistant breast cancer cells from drug-sensitive cells in lipid composition and biophysical properties, suggesting that cancer cells acquire a drug-resistant phenotype through the alteration of lipid synthesis to inhibit intracellular drug transport to protect from cytotoxic effect. In cancer cells, epigenetic changes (e.g....

  14. High current vacuum closing switch

    International Nuclear Information System (INIS)

    Dolgachev, G.I.; Maslennikov, D.D.; Romanov, A.S.; Ushakov, A.G.

    2005-01-01

    The paper proposes a powerful pulsed closing vacuum switch for high current commutation consisting of series of the vacuum diodes with near 1 mm gaps having closing time determined by the gaps shortening with the near-electrode plasmas [ru

  15. Close to the Sky

    Science.gov (United States)

    2007-11-01

    Today, a new ALMA outreach and educational book was publicly presented to city officials of San Pedro de Atacama in Chile, as part of the celebrations of the anniversary of the Andean village. ESO PR Photo 50a/07 ESO PR Photo 50a/07 A Useful Tool for Schools Entitled "Close to the sky: Biological heritage in the ALMA area", and edited in English and Spanish by ESO in Chile, the book collects unique on-site observations of the flora and fauna of the ALMA region performed by experts commissioned to investigate it and to provide key initiatives to protect it. "I thank the ALMA project for providing us a book that will surely be a good support for the education of children and youngsters of San Pedro de Atacama. Thanks to this publication, we expect our rich flora and fauna to be better known. I invite teachers and students to take advantage of this educational resource, which will be available in our schools", commented Ms. Sandra Berna, the Mayor of San Pedro de Atacama, who was given the book by representatives of the ALMA global collaboration project. Copies of the book 'Close to the sky' will be donated to all schools in the area, as a contribution to the education of students and young people in northern Chile. "From the very beginning of the project, ALMA construction has had a firm commitment to environment and local culture, protecting unique flora and fauna species and preserving old estancias belonging to the Likan Antai culture," said Jacques Lassalle, who represented ALMA at the hand-over. "Animals like the llama, the fox or the condor do not only live in the region where ALMA is now being built, but they are also key elements of the ancient Andean constellations. In this sense they are part of the same sky that will be explored by ALMA in the near future." ESO PR Photo 50c/07 ESO PR Photo 50c/07 Presentation of the ALMA book The ALMA Project is a giant, international observatory currently under construction on the high-altitude Chajnantor site in Chile

  16. Biomechanical and biophysical environment of bone from the macroscopic to the pericellular and molecular level.

    Science.gov (United States)

    Ren, Li; Yang, Pengfei; Wang, Zhe; Zhang, Jian; Ding, Chong; Shang, Peng

    2015-10-01

    Bones with complicated hierarchical configuration and microstructures constitute the load-bearing system. Mechanical loading plays an essential role in maintaining bone health and regulating bone mechanical adaptation (modeling and remodeling). The whole-bone or sub-region (macroscopic) mechanical signals, including locomotion-induced loading and external actuator-generated vibration, ultrasound, oscillatory skeletal muscle stimulation, etc., give rise to sophisticated and distinct biomechanical and biophysical environments at the pericellular (microscopic) and collagen/mineral molecular (nanoscopic) levels, which are the direct stimulations that positively influence bone adaptation. While under microgravity, the stimulations decrease or even disappear, which exerts a negative influence on bone adaptation. A full understanding of the biomechanical and biophysical environment at different levels is necessary for exploring bone biomechanical properties and mechanical adaptation. In this review, the mechanical transferring theories from the macroscopic to the microscopic and nanoscopic levels are elucidated. First, detailed information of the hierarchical structures and biochemical composition of bone, which are the foundations for mechanical signal propagation, are presented. Second, the deformation feature of load-bearing bone during locomotion is clarified as a combination of bending and torsion rather than simplex bending. The bone matrix strains at microscopic and nanoscopic levels directly induced by bone deformation are critically discussed, and the strain concentration mechanism due to the complicated microstructures is highlighted. Third, the biomechanical and biophysical environments at microscopic and nanoscopic levels positively generated during bone matrix deformation or by dynamic mechanical loadings induced by external actuators, as well as those negatively affected under microgravity, are systematically discussed, including the interstitial fluid flow

  17. Hierarchy and Interactions in Environmental Interfaces Regarded as Biophysical Complex Systems

    Science.gov (United States)

    Mihailovic, Dragutin T.; Balaz, Igor

    The field of environmental sciences is abundant with various interfaces and is the right place for the application of new fundamental approaches leading towards a better understanding of environmental phenomena. For example, following the definition of environmental interface by Mihailovic and Balaž [23], such interface can be placed between: human or animal bodies and surrounding air, aquatic species and water and air around them, and natural or artificially built surfaces (vegetation, ice, snow, barren soil, water, urban communities) and the atmosphere. Complex environmental interface systems are open and hierarchically organised, interactions between their constituent parts are nonlinear, and the interaction with the surrounding environment is noisy. These systems are therefore very sensitive to initial conditions, deterministic external perturbations and random fluctuations always present in nature. The study of noisy non-equilibrium processes is fundamental for modelling the dynamics of environmental interface systems and for understanding the mechanisms of spatio-temporal pattern formation in contemporary environmental sciences, particularly in environmental fluid mechanics. In modelling complex biophysical systems one of the main tasks is to successfully create an operative interface with the external environment. It should provide a robust and prompt translation of the vast diversity of external physical and/or chemical changes into a set of signals, which are "understandable" for an organism. Although the establishment of organisation in any system is of crucial importance for its functioning, it should not be forgotten that in biophysical systems we deal with real-life problems where a number of other conditions should be reached in order to put the system to work. One of them is the proper supply of the system by the energy. Therefore, we will investigate an aspect of dynamics of energy flow based on the energy balance equation. The energy as well as

  18. Representing biophysical landscape interactions in soil models by bridging disciplines and scales.

    Science.gov (United States)

    van der Ploeg, M. J.; Carranza, C.; Teixeira da Silva, R.; te Brake, B.; Baartman, J.; Robinson, D.

    2017-12-01

    The combination of climate change, population growth and soil threats including carbon loss, biodiversity decline and erosion, increasingly confront the global community (Schwilch et al., 2016). One major challenge in studying processes involved in soil threats, landscape resilience, ecosystem stability, sustainable land management and resulting economic consequences, is that it is an interdisciplinary field (Pelletier et al., 2012). Less stringent scientific disciplinary boundaries are therefore important (Liu et al., 2007), because as a result of disciplinary focus, ambiguity may arise on the understanding of landscape interactions. This is especially true in the interaction between a landscape's physical and biological processes (van der Ploeg et al. 2012). Biophysical landscape interactions are those biotic and abiotic processes in a landscape that have an influence on the developments within and evolution of a landscape. An important aspect in biophysical landscape interactions is the differences in scale related to the various processes that play a role in these systems. Moreover, the interplay between the physical landscape and the occurring vegetation, which often co-evolve, and the resulting heterogeneity and emerging patterns are the reason why it is so challenging to establish a theoretical basis to describe biophysical processes in landscapes (e.g. te Brake et al. 2013, Robinson et al. 2016). Another complicating factor is the response of vegetation to changing environmental conditions, including a possible, and often unknown, time-lag (e.g. Metzger et al., 2009). An integrative description for modelling biophysical interactions has been a long standing goal in soil science (Vereecken et al., 2016). We need the development of soil models that are more focused on networks, connectivity and feedbacks incorporating the most important aspects of our detailed mechanistic modelling (Paola & Leeder, 2011). Additionally, remote sensing measurement techniques

  19. Closed cycle device

    International Nuclear Information System (INIS)

    Ruby, L.E.; Witt, D.L.; Staley, C.F.

    1975-01-01

    A gas dynamic laser wherein the lasing fluid is recirculated in a closed loop is described. The flow can be assumed to start with the lasing gas passing through a cascade of supersonic nozzles. This low pressure, high velocity gas is then passed through a lasing cavity where the lasing action takes place. The energy of the high velocity gas stream is converted back to static pressure in a supersonic diffuser. The diffuser is constructed with (1) variable geometry, and (2) provisions for bleeding off the boundary layer for improved efficiency. Downstream of the supersonic diffuser there is a heat exchanger which partially cools the gas in the loop. This partially cooled gas is then supplied to a compressor where the pressure and temperature are raised back to the level at the start of the flow. The lasing gas is directed from the exit of the compressor to a manifold upstream of the cascade of supersonic nozzles. The compressor only supplies a pressure rise equal to the pressure loss by inefficiencies in the nozzle, the supersonic diffuser and the pressure drop in the heatexchanger and plumbing. To provide for cooling of the compressor, the gas bled from the diffuser is cooled by a second heat exchanger and pumped back to compressor inlet pressure and introduced into the compressor for cooling. In steady state operation, both heat exchangers referred to above, are designed to regulatethe nozzle inlet gas temperature by removing the amount of heat energy added by compressing minus the amount of energy extracted in the lasing beam and energy lost to the environment. The compressor and pumping means for cooling the compressor can be driven by any means desired. (U.S.)

  20. Superimposing various biophysical and social scales in a rapidly changing rural area (SW Niger)

    Science.gov (United States)

    Leduc, Christian; Massuel, Sylvain; Favreau, Guillaume; Cappelaere, Bernard; Leblanc, Marc; Bachir, Salifou; Ousmane, Boureïma

    2014-05-01

    In SW Niger, close to Niamey, a detailed hydrological survey has been developed for the last 20 years (international experiments HAPEX-SAHEL and later AMMA), investigating the distribution of water in atmosphere, surface, soil and aquifers. It covers an area of about 10 000 km2, with a series of imbricated scales of instrumentation, in time and space. This dense long term field observation led to many major scientific results. Among them, one of the most original and paradoxical is the continuous rise of the water table, even during the severe droughts of the 1970s and 1980s (about 3 m in the last 30 years). In spite of a large apparent homogeneity of the biophysical environment throughout the region, numerous heterogeneities exist at different scales, complicating the hydrological analysis. On the surface, the hydrological system was, ~6000 years ago, a structured drainage network leading to the Niger River. It was later broken into much smaller elements by aeolian dunes deposited during arid episodes and the study area now appears as a juxtaposition of hundreds of small endorheic catchments (most often 1 to 20 km2) where the surface runoff finally ends in temporary ponds. During most violent rainy events, erosion can be locally very severe and modify durably the size of the catchment and the local hydrology. Conversely, during smaller rainy events, surface runoff may never reach the ponds because it infiltrates in more permeable zones at mid-slope. The actual surface area of the catchment contributing to the surface runoff thus varies considerably with time. Because of their great number, only a few catchments are instrumented and extrapolation of measurements to ungauged catchments is an additional difficulty. Most of water temporarily stored in ponds infiltrates and recharges groundwater. The Continental Terminal (CT) aquifer system is made of three independent layers, of which the upper one (CT3) is only considered here. The CT aquifer systems is a

  1. A subsequent closed-form description of propagated signaling phenomena in the membrane of an axon

    Science.gov (United States)

    Melendy, Robert. F.

    2016-05-01

    I recently introduced a closed-form description of propagated signaling phenomena in the membrane of an axon [R.F. Melendy, Journal of Applied Physics 118, 244701 (2015)]. Those results demonstrate how intracellular conductance, the thermodynamics of magnetization, and current modulation, function together in generating an action potential in a unified, closed-form description. At present, I report on a subsequent closed-form model that unifies intracellular conductance and the thermodynamics of magnetization, with the membrane electric field, Em. It's anticipated this work will compel researchers in biophysics, physical biology, and the computational neurosciences, to probe deeper into the classical and quantum features of membrane magnetization and signaling, informed by the computational features of this subsequent model.

  2. A subsequent closed-form description of propagated signaling phenomena in the membrane of an axon

    Energy Technology Data Exchange (ETDEWEB)

    Melendy, Robert F., E-mail: rfmelendy@liberty.edu [School of Engineering and Computational Science, Liberty University, Lynchburg, Virginia, 24515 (United States)

    2016-05-15

    I recently introduced a closed-form description of propagated signaling phenomena in the membrane of an axon [R.F. Melendy, Journal of Applied Physics 118, 244701 (2015)]. Those results demonstrate how intracellular conductance, the thermodynamics of magnetization, and current modulation, function together in generating an action potential in a unified, closed-form description. At present, I report on a subsequent closed-form model that unifies intracellular conductance and the thermodynamics of magnetization, with the membrane electric field, E{sub m}. It’s anticipated this work will compel researchers in biophysics, physical biology, and the computational neurosciences, to probe deeper into the classical and quantum features of membrane magnetization and signaling, informed by the computational features of this subsequent model.

  3. Biophysical sciences

    International Nuclear Information System (INIS)

    1988-01-01

    One of the objectives of the National Accelerator Centre is to provide facilities for radiotherapy of cancer patients. It is therefore logical that some scientific effort be directed towards understanding the underlying molecular mechanisms involved in carcinogenesis and the genetic effects induced by radiation in cells in culture. 5 refs., 1 tab

  4. Biophysical sciences

    International Nuclear Information System (INIS)

    1988-01-01

    The neutron therapy system consists of an isocentric gantry capable of ± 185 degrees rotation. Field sizes of between 5 x 5 cm 2 and 30 x 30 cm 2 are defined by a rotatable continuously variable collimator. Neutrons are produced by the p(66 MeV)/Be(40 MeV) reaction. Basic neutron beam data were initially measured in order to provide sufficient information for radiobiological experiments to be undertaken. Some of these experiments indicated a differential in the biological effectiveness of the beam at the surface and at depth in a phantom. In order to reduce this differential at 2.5 cm thick polyethylene beam-hardening filter has been mounted in the treatment head. In addition beam-flattening filters are now also being used to flatten the beam profiles at depth in phantom. Measurements of the characteristics of the beam with the new configuration are still in progress. 12 figs., 6 refs

  5. Biophysical chemistry

    International Nuclear Information System (INIS)

    Klein, M.P.

    1987-01-01

    Phosphorus-31 NMR spectroscopy is evolving into an important means for determining the in vivo concentrations of phosphorylated metabolites and is now entering the clinical arena. Our previous contributions to this field demonstrated the feasibility of employing implanted radio frequency coils around organs of laboratory animals to permit eliciting the NMR spectra over long periods to establish normative spectra. Using these devices and techniques we have determined phosphorus exchange reactions in rat hearts and kidney, in situ, and have demonstrated that there are pools of metabolic intermediates that are not directly visible in the conventional high resolution NMR spectra. Comparison of the results from NMR spectroscopy with those obtained from radiolabeling studies on chick embryo fibroblasts also showed that there are significant pools of phosphorus not visible in the P-31 NMR spectrum. Both sets of studies suggest that compartmentation occurs. The invisibility of these pools is assumed to result from the immobilization of the molecules by cellular macromolecules or organelles

  6. Membrane Biophysics

    CERN Document Server

    Ashrafuzzaman, Mohammad

    2013-01-01

    Physics, mathematics and chemistry all play a vital role in understanding the true nature and functioning of biological membranes, key elements of living processes. Besides simple spectroscopic observations and electrical measurements of membranes we address in this book the phenomena of coexistence and independent existence of different membrane components using various theoretical approaches. This treatment will be helpful for readers who want to understand biological processes by applying both simple observations and fundamental scientific analysis. It provides a deep understanding of the causes and effects of processes inside membranes, and will thus eventually open new doors for high-level pharmaceutical approaches towards fighting membrane- and cell-related diseases.

  7. Beta relaxation of nonpolymeric liquids close to the glass transition

    DEFF Research Database (Denmark)

    Olsen, Niels Boye; Christensen, Tage Emil; Dyre, Jeppe

    2000-01-01

    Dielectric beta relaxation in a pyridine-toluene solution is studied close to the glass transition. Loss peak frequency and maximum loss both exhibit thermal hysteresis. An annealing-state-independent parameter involving loss and loss peak frequency is identified. This parameter has a simple...

  8. A Diagnosis of Biophysical and Socio-Economic Factors Influencing Farmers' Choice to Adopt Organic or Conventional Farming Systems for Cotton Production.

    Science.gov (United States)

    Riar, Amritbir; Mandloi, Lokendra S; Poswal, Randhir S; Messmer, Monika M; Bhullar, Gurbir S

    2017-01-01

    Organic agriculture is one of the most widely known alternative production systems advocated for its benefits to soil, environment, health and economic well-being of farming communities. Rapid increase in the market demand for organic products presents a remarkable opportunity for expansion of organic agriculture. A thorough understanding of the context specific motivations of farmers for adoption of organic farming systems is important so that appropriate policy measures are put in place. With an aim of understanding the social and biophysical motivations of organic and conventional cotton farmers for following their respective farming practices, a detailed farm survey was conducted in Nimar valley of Madhya Pradesh state in central India. The study area was chosen for being an important region for cotton production, where established organic and conventional farms operate under comparable circumstances. We found considerable variation among organic and conventional farmers for their social and biophysical motivations. Organic farmers were motivated by the sustainability of cotton production and growing safer food without pesticides, whereas conventional farmers were sensitive about their reputation in community. Organic farmers with larger holdings were more concerned about closed nutrient cycles and reducing their dependence on external inputs, whereas medium and small holding organic farmers were clearly motivated by the premium price of organic cotton. Higher productivity was the only important motivation for conventional farmers with larger land holdings. We also found considerable yield gaps among different farms, both under conventional and organic management, that need to be addressed through extension and training. Our findings suggest that research and policy measures need to be directed toward strengthening of extension services, local capacity building, enhancing availability of suitable inputs and market access for organic farmers.

  9. Multi-year coupled biogeochemical and biophysical impacts of restoring drained agricultural peatlands to wetlands across the Sacramento-San Joaquin Delta, California, USA.

    Science.gov (United States)

    Hemes, K. S.; Eichelmann, E.; Chamberlain, S.; Knox, S. H.; Oikawa, P.; Sturtevant, C.; Verfaillie, J. G.; Baldocchi, D. D.

    2017-12-01

    Globally, delta ecosystems are critical for human livelihoods, but are at increasingly greater risk of degradation. The Sacramento-San Joaquin River Delta (`Delta') has been subsiding dramatically, losing close to 100 Tg of carbon since the mid 19th century due in large part to agriculture-induced oxidation of the peat soils through drainage and cultivation. Efforts to re-wet the peat soils through wetland restoration are attractive as climate mitigation activities. While flooded wetland systems have the potential to sequester significant amounts of carbon as photosynthesis outpaces aerobic respiration, the highly-reduced conditions can result in significant methane emissions. This study will utilize three years (2014-2016) of continuous, gap-filled, CO2 and CH4 flux data from a mesonetwork of seven eddy covariance towers in the Delta to compute GHG budgets for the restored wetlands and agricultural baseline sites measured. Along with biogeochemical impacts of wetland restoration, biophysical impacts such as changes in reflectance, energy partitioning, and surface roughness, can have significant local to regional impacts on air temperature and heat fluxes. We hypothesize that despite flooded wetlands reducing albedo, wetland land cover will cool the near-surface air temperature due to increased net radiation being preferentially partitioned into latent heat flux and rougher canopy conditions allowing for more turbulent mixing with the atmosphere. This study will investigate the seasonal and diurnal patterns of turbulent energy fluxes and the surface properties that drive them. With nascent policy mechanisms set to compensate landowners and farmers for low emission land use practices beyond reforestation, it is essential that policy mechanisms take into consideration how the biophysical impacts of land use change could drive local to regional-scale climatic perturbations, enhancing or attenuating the biogeochemical impacts.

  10. A Diagnosis of Biophysical and Socio-Economic Factors Influencing Farmers’ Choice to Adopt Organic or Conventional Farming Systems for Cotton Production

    Directory of Open Access Journals (Sweden)

    Amritbir Riar

    2017-07-01

    Full Text Available Organic agriculture is one of the most widely known alternative production systems advocated for its benefits to soil, environment, health and economic well-being of farming communities. Rapid increase in the market demand for organic products presents a remarkable opportunity for expansion of organic agriculture. A thorough understanding of the context specific motivations of farmers for adoption of organic farming systems is important so that appropriate policy measures are put in place. With an aim of understanding the social and biophysical motivations of organic and conventional cotton farmers for following their respective farming practices, a detailed farm survey was conducted in Nimar valley of Madhya Pradesh state in central India. The study area was chosen for being an important region for cotton production, where established organic and conventional farms operate under comparable circumstances. We found considerable variation among organic and conventional farmers for their social and biophysical motivations. Organic farmers were motivated by the sustainability of cotton production and growing safer food without pesticides, whereas conventional farmers were sensitive about their reputation in community. Organic farmers with larger holdings were more concerned about closed nutrient cycles and reducing their dependence on external inputs, whereas medium and small holding organic farmers were clearly motivated by the premium price of organic cotton. Higher productivity was the only important motivation for conventional farmers with larger land holdings. We also found considerable yield gaps among different farms, both under conventional and organic management, that need to be addressed through extension and training. Our findings suggest that research and policy measures need to be directed toward strengthening of extension services, local capacity building, enhancing availability of suitable inputs and market access for organic farmers.

  11. Epigenetic modulation of the biophysical properties of drug-resistant cell lipids to restore drug transport and endocytic functions.

    Science.gov (United States)

    Vijayaraghavalu, Sivakumar; Peetla, Chiranjeevi; Lu, Shan; Labhasetwar, Vinod

    2012-09-04

    In our recent studies exploring the biophysical characteristics of resistant cell lipids, and the role they play in drug transport, we demonstrated the difference of drug-resistant breast cancer cells from drug-sensitive cells in lipid composition and biophysical properties, suggesting that cancer cells acquire a drug-resistant phenotype through the alteration of lipid synthesis to inhibit intracellular drug transport to protect from cytotoxic effect. In cancer cells, epigenetic changes (e.g., DNA hypermethylation) are essential to maintain this drug-resistant phenotype. Thus, altered lipid synthesis may be linked to epigenetic mechanisms of drug resistance. We hypothesize that reversing DNA hypermethylation in resistant cells with an epigenetic drug could alter lipid synthesis, changing the cell membrane's biophysical properties to facilitate drug delivery to overcome drug resistance. Herein we show that treating drug-resistant breast cancer cells (MCF-7/ADR) with the epigenetic drug 5-aza-2'-deoxycytidine (decitabine) significantly alters cell lipid composition and biophysical properties, causing the resistant cells to acquire biophysical characteristics similar to those of sensitive cell (MCF-7) lipids. Following decitabine treatment, resistant cells demonstrated increased sphingomyelinase activity, resulting in a decreased sphingomyelin level that influenced lipid domain structures, increased membrane fluidity, and reduced P-glycoprotein expression. Changes in the biophysical characteristics of resistant cell lipids facilitated doxorubicin transport and restored endocytic function for drug delivery with a lipid-encapsulated form of doxorubicin, enhancing the drug efficacy. In conclusion, we have established a new mechanism for efficacy of an epigenetic drug, mediated through changes in lipid composition and biophysical properties, in reversing cancer drug resistance.

  12. Linking biophysical models and public preferences for ecosystem service assessments: a case study for the Southern Rocky Mountains

    Science.gov (United States)

    Bagstad, Kenneth J.; Reed, James; Semmens, Darius J.; Sherrouse, Ben C.; Troy, Austin

    2016-01-01

    Through extensive research, ecosystem services have been mapped using both survey-based and biophysical approaches, but comparative mapping of public values and those quantified using models has been lacking. In this paper, we mapped hot and cold spots for perceived and modeled ecosystem services by synthesizing results from a social-values mapping study of residents living near the Pike–San Isabel National Forest (PSI), located in the Southern Rocky Mountains, with corresponding biophysically modeled ecosystem services. Social-value maps for the PSI were developed using the Social Values for Ecosystem Services tool, providing statistically modeled continuous value surfaces for 12 value types, including aesthetic, biodiversity, and life-sustaining values. Biophysically modeled maps of carbon sequestration and storage, scenic viewsheds, sediment regulation, and water yield were generated using the Artificial Intelligence for Ecosystem Services tool. Hotspots for both perceived and modeled services were disproportionately located within the PSI’s wilderness areas. Additionally, we used regression analysis to evaluate spatial relationships between perceived biodiversity and cultural ecosystem services and corresponding biophysical model outputs. Our goal was to determine whether publicly valued locations for aesthetic, biodiversity, and life-sustaining values relate meaningfully to results from corresponding biophysical ecosystem service models. We found weak relationships between perceived and biophysically modeled services, indicating that public perception of ecosystem service provisioning regions is limited. We believe that biophysical and social approaches to ecosystem service mapping can serve as methodological complements that can advance ecosystem services-based resource management, benefitting resource managers by showing potential locations of synergy or conflict between areas supplying ecosystem services and those valued by the public.

  13. Photobiology of Symbiodinium revisited: bio-physical and bio-optical signatures

    Science.gov (United States)

    Hennige, S. J.; Suggett, D. J.; Warner, M. E.; McDougall, K. E.; Smith, D. J.

    2009-03-01

    Light is often the most abundant resource within the nutrient-poor waters surrounding coral reefs. Consequently, zooxanthellae ( Symbiodinium spp.) must continually photoacclimate to optimise productivity and ensure coral success. In situ coral photobiology is becoming dominated by routine assessments using state-of-the-art non-invasive bio-optical or chlorophyll a fluorescence (bio-physical) techniques. Multiple genetic types of Symbiodinium are now known to exist; however, little focus has been given as to how these types differ in terms of characteristics that are observable using these techniques. Therefore, this investigation aimed to revisit and expand upon a pivotal study by Iglesias-Prieto and Trench (1994) by comparing the photoacclimation characteristics of different Symbiodinium types based on their bio-physical (chlorophyll a fluorescence, reaction centre counts) and bio-optical (optical absorption, pigment concentrations) ‘signatures’. Signatures described here are unique to Symbiodinium type and describe phenotypic responses to set conditions, and hence are not suitable to describe taxonomic structure of in hospite Symbiodinium communities. In this study, eight Symbiodinium types from clades and sub-clades (A-B, F) were grown under two PFDs (Photon Flux Density) and examined. The photoacclimation response by Symbiodinium was highly variable between algal types for all bio-physical and for many bio-optical measurements; however, a general preference to modifying reaction centre content over effective antennae-absorption was observed. Certain bio-optically derived patterns, such as light absorption, were independent of algal type and, when considered per photosystem, were matched by reaction centre stoichiometry. Only by better understanding genotypic and phenotypic variability between Symbiodinium types can future studies account for the relative taxonomic and physiological contribution by Symbiodinium to coral acclimation.

  14. PyFolding: Open-Source Graphing, Simulation, and Analysis of the Biophysical Properties of Proteins.

    Science.gov (United States)

    Lowe, Alan R; Perez-Riba, Albert; Itzhaki, Laura S; Main, Ewan R G

    2018-02-06

    For many years, curve-fitting software has been heavily utilized to fit simple models to various types of biophysical data. Although such software packages are easy to use for simple functions, they are often expensive and present substantial impediments to applying more complex models or for the analysis of large data sets. One field that is reliant on such data analysis is the thermodynamics and kinetics of protein folding. Over the past decade, increasingly sophisticated analytical models have been generated, but without simple tools to enable routine analysis. Consequently, users have needed to generate their own tools or otherwise find willing collaborators. Here we present PyFolding, a free, open-source, and extensible Python framework for graphing, analysis, and simulation of the biophysical properties of proteins. To demonstrate the utility of PyFolding, we have used it to analyze and model experimental protein folding and thermodynamic data. Examples include: 1) multiphase kinetic folding fitted to linked equations, 2) global fitting of multiple data sets, and 3) analysis of repeat protein thermodynamics with Ising model variants. Moreover, we demonstrate how PyFolding is easily extensible to novel functionality beyond applications in protein folding via the addition of new models. Example scripts to perform these and other operations are supplied with the software, and we encourage users to contribute notebooks and models to create a community resource. Finally, we show that PyFolding can be used in conjunction with Jupyter notebooks as an easy way to share methods and analysis for publication and among research teams. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  15. Similar Biophysical Abnormalities in Glomeruli and Podocytes from Two Distinct Models.

    Science.gov (United States)

    Embry, Addie E; Liu, Zhenan; Henderson, Joel M; Byfield, F Jefferson; Liu, Liping; Yoon, Joonho; Wu, Zhenzhen; Cruz, Katrina; Moradi, Sara; Gillombardo, C Barton; Hussain, Rihanna Z; Doelger, Richard; Stuve, Olaf; Chang, Audrey N; Janmey, Paul A; Bruggeman, Leslie A; Miller, R Tyler

    2018-03-23

    Background FSGS is a pattern of podocyte injury that leads to loss of glomerular function. Podocytes support other podocytes and glomerular capillary structure, oppose hemodynamic forces, form the slit diaphragm, and have mechanical properties that permit these functions. However, the biophysical characteristics of glomeruli and podocytes in disease remain unclear. Methods Using microindentation, atomic force microscopy, immunofluorescence microscopy, quantitative RT-PCR, and a three-dimensional collagen gel contraction assay, we studied the biophysical and structural properties of glomeruli and podocytes in chronic (Tg26 mice [HIV protein expression]) and acute (protamine administration [cytoskeletal rearrangement]) models of podocyte injury. Results Compared with wild-type glomeruli, Tg26 glomeruli became progressively more deformable with disease progression, despite increased collagen content. Tg26 podocytes had disordered cytoskeletons, markedly abnormal focal adhesions, and weaker adhesion; they failed to respond to mechanical signals and exerted minimal traction force in three-dimensional collagen gels. Protamine treatment had similar but milder effects on glomeruli and podocytes. Conclusions Reduced structural integrity of Tg26 podocytes causes increased deformability of glomerular capillaries and limits the ability of capillaries to counter hemodynamic force, possibly leading to further podocyte injury. Loss of normal podocyte mechanical integrity could injure neighboring podocytes due to the absence of normal biophysical signals required for podocyte maintenance. The severe defects in podocyte mechanical behavior in the Tg26 model may explain why Tg26 glomeruli soften progressively, despite increased collagen deposition, and may be the basis for the rapid course of glomerular diseases associated with severe podocyte injury. In milder injury (protamine), similar processes occur but over a longer time. Copyright © 2018 by the American Society of Nephrology.

  16. Quality Saving Mechanisms of Mitochondria during Aging in a Fully Time-Dependent Computational Biophysical Model.

    Directory of Open Access Journals (Sweden)

    Daniel Mellem

    Full Text Available Mitochondria are essential for the energy production of eukaryotic cells. During aging mitochondria run through various processes which change their quality in terms of activity, health and metabolic supply. In recent years, many of these processes such as fission and fusion of mitochondria, mitophagy, mitochondrial biogenesis and energy consumption have been subject of research. Based on numerous experimental insights, it was possible to qualify mitochondrial behaviour in computational simulations. Here, we present a new biophysical model based on the approach of Figge et al. in 2012. We introduce exponential decay and growth laws for each mitochondrial process to derive its time-dependent probability during the aging of cells. All mitochondrial processes of the original model are mathematically and biophysically redefined and additional processes are implemented: Mitochondrial fission and fusion is separated into a metabolic outer-membrane part and a protein-related inner-membrane part, a quality-dependent threshold for mitophagy and mitochondrial biogenesis is introduced and processes for activity-dependent internal oxidative stress as well as mitochondrial repair mechanisms are newly included. Our findings reveal a decrease of mitochondrial quality and a fragmentation of the mitochondrial network during aging. Additionally, the model discloses a quality increasing mechanism due to the interplay of the mitophagy and biogenesis cycle and the fission and fusion cycle of mitochondria. It is revealed that decreased mitochondrial repair can be a quality saving process in aged cells. Furthermore, the model finds strategies to sustain the quality of the mitochondrial network in cells with high production rates of reactive oxygen species due to large energy demands. Hence, the model adds new insights to biophysical mechanisms of mitochondrial aging and provides novel understandings of the interdependency of mitochondrial processes.

  17. From autopoiesis to neurophenomenology: Francisco Varela's exploration of the biophysics of being

    Directory of Open Access Journals (Sweden)

    DAVID RUDRAUF

    2003-01-01

    Full Text Available This paper reviews in detail Francisco Varela's work on subjectivity and consciousness in the biological sciences. His original approach to this "hard problem" presents a subjectivity that is radically intertwined with its biological and physical roots. It must be understood within the framework of his theory of a concrete, embodied dynamics, grounded in his general theory of autonomous systems. Through concepts and paradigms such as biological autonomy, embodiment and neurophenomenology, the article explores the multiple levels of circular causality assumed by Varela to play a fundamental role in the emergence of human experience. The concept of biological autonomy provides the necessary and sufficient conditions for characterizing biological life and identity as an emergent and circular self-producing process. Embodiment provides a systemic and dynamical framework for understanding how a cognitive -a mind- can arise in an organism in the midst of its operational cycles of internal regulation and ongoing sensorimotor coupling. Global subjective properties can emerge at different levels from the interactions of components and can reciprocally constrain local processes through an ongoing, recursive morphodynamics. Neurophenomenology is a supplementary step in the study of consciousness. Through a rigorous method, it advocates the careful examination of experience with first-person methodologies. It attempts to create heuristic mutual constraints between biophysical data and data produced by accounts of subjective experience. The aim is to explicitly ground the active and disciplined insight the subject has about his/her experience in a biophysical emergent process. Finally, we discuss Varela's essential contribution to our understanding of the generation of consciousness in the framework of what we call his "biophysics of being."

  18. From dating to biophysics -- 20 years of progress in applied ESR spectroscopy

    International Nuclear Information System (INIS)

    Regulla, Dieter

    2000-01-01

    ESR spectroscopy represents a tool for quantitative radiation analysis that was developed somehow simultaneously for dating purposes in Japan and in Germany for high-level standardization, in the mid-seventies. Meanwhile, ESR dosimetry has reached an established metrology level. Present research fields of ESR dosimetry consider post-accident dose reconstruction in the environment, and biophysical dosimetry using human tissues. The latter promises a re-definition of radiation risk for chronicle exposure to be derived from individuals of the early nuclear facilities in Russia, and hopefully United States in the future. An attempt is made to sketch development and potential future of the ESR technique

  19. Exploring the biophysical properties of phytosterols in the plasma membrane for novel cancer prevention strategies.

    Science.gov (United States)

    Fakih, Omar; Sanver, Didem; Kane, David; Thorne, James L

    2018-05-03

    Cancer is a global problem with no sign that incidences are reducing. The great costs associated with curing cancer, through developing novel treatments and applying patented therapies, is an increasing burden to developed and developing nations alike. These financial and societal problems will be alleviated by research efforts into prevention, or treatments that utilise off-patent or repurposed agents. Phytosterols are natural components of the diet found in an array of seeds, nuts and vegetables and have been added to several consumer food products for the management of cardio-vascular disease through their ability to lower LDL-cholesterol levels. In this review, we provide a connected view between the fields of structural biophysics and cellular and molecular biology to evaluate the growing evidence that phytosterols impair oncogenic pathways in a range of cancer types. The current state of understanding of how phytosterols alter the biophysical properties of plasma membrane is described, and the potential for phytosterols to be repurposed from cardio-vascular to oncology therapeutics. Through an overview of the types of biophysical and molecular biology experiments that have been performed to date, this review informs the reader of the molecular and biophysical mechanisms through which phytosterols could have anti-cancer properties via their interactions with the plasma cell membrane. We also outline emerging and under-explored areas such as computational modelling, improved biomimetic membranes and ex vivo tissue evaluation. Focus of future research in these areas should improve understanding, not just of phytosterols in cancer cell biology but also to give insights into the interaction between the plasma membrane and the genome. These fields are increasingly providing meaningful biological and clinical data but iterative experiments between molecular biology assays, biosynthetic membrane studies and computational membrane modelling improve and refine our

  20. Biophysical Insights into the Inhibitory Mechanism of Non-Nucleoside HIV-1 Reverse Transcriptase Inhibitors

    Directory of Open Access Journals (Sweden)

    Nicolas Sluis-Cremer

    2013-11-01

    Full Text Available HIV-1 reverse transcriptase (RT plays a central role in HIV infection. Current United States Federal Drug Administration (USFDA-approved antiretroviral therapies can include one of five approved non-nucleoside RT inhibitors (NNRTIs, which are potent inhibitors of RT activity. Despite their crucial clinical role in treating and preventing HIV-1 infection, their mechanism of action remains elusive. In this review, we introduce RT and highlight major advances from experimental and computational biophysical experiments toward an understanding of RT function and the inhibitory mechanism(s of NNRTIs.

  1. Fluctuation theory of solutions applications in chemistry, chemical engineering, and biophysics

    CERN Document Server

    Smith, Paul E

    2013-01-01

    There are essentially two theories of solutions that can be considered exact: the McMillan-Mayer theory and Fluctuation Solution Theory (FST). The first is mostly limited to solutes at low concentrations, while FST has no such issue. It is an exact theory that can be applied to any stable solution regardless of the number of components and their concentrations, and the types of molecules and their sizes. Fluctuation Theory of Solutions: Applications in Chemistry, Chemical Engineering, and Biophysics outlines the general concepts and theoretical basis of FST and provides a range of applications

  2. Microscale Ocean Biophysics, Aspen Center for Physics: January 11-16 2015

    Science.gov (United States)

    2017-04-19

    dissolved   organic  matter  persist  in  the  deep  ocean:  Is  the  solution   dilution ?”     8.45  –  Kwangmin  Son...AUTHORS 7. PERFORMING ORGANIZATION NAMES AND ADDRESSES 15. SUBJECT TERMS b. ABSTRACT 2. REPORT TYPE 17. LIMITATION OF ABSTRACT 15. NUMBER OF PAGES...Microscale Ocean Biophysics, Aspen Center for Physics, January 11-16, 2015 Microscopic organisms control ocean processes at global scales. However

  3. The design and analysis of a teaching and learning strategy in Biophysics Course

    Directory of Open Access Journals (Sweden)

    Beatriz Aiziczon

    2010-01-01

    Full Text Available This work presents the design and analysis of a teaching and learning strategy of Biophysics in the Medical career, in the mark of the Ausubelian Significant Learning Model, to overtake the Model of Transmission-Reception of knowledge. It is an integrative Module constructed from our previous theoretical Model and based on the authors' previous works (AIZICZON; CUDMANI, 2004, 2005, 2007. We analyze applications of conceptual maps strategy and the previous organizing in Medical Education (AUSUBEL, 1981; MOREIRA, 1983, 1999 promoting the integration of concepts allowing the progressive differentiation and the integrative reorganization as well as the formative evaluation. In this work we analyze the experience with teachers.

  4. [Fluctuations in biophysical measurements as a result of variations in solar activity].

    Science.gov (United States)

    Peterson, T F

    1995-01-01

    A theory is proposed to explain variations in the net electrical charge of biological substances at the Earth's surface. These are shown to occur in association with changes in the solar wind and geomagnetic field. It is suggested that a liquid dielectric's net volume charge will imitate pH effects, influence chemical reaction rates, and alter ion transfer mechanisms in biophysical systems. An experiment is described which measures dielectric volume charge, or non-neutrality, to allow correlation of this property with daily, 28-day, and 11-year fluctuation patterns in geophysical and satellite data associated with solar activity and the interplanetary magnetic field.

  5. Biophysical controls on light response of net CO2 exchange in a winter wheat field in the North China Plain.

    Directory of Open Access Journals (Sweden)

    Xiaojuan Tong

    Full Text Available To investigate the impacts of biophysical factors on light response of net ecosystem exchange (NEE, CO2 flux was measured using the eddy covariance technique in a winter wheat field in the North China Plain from 2003 to 2006. A rectangular hyperbolic function was used to describe NEE light response. Maximum photosynthetic capacity (P max was 46.6 ± 4.0 µmol CO2 m(-2 s(-1 and initial light use efficiency (α 0.059 ± 0.006 µmol µmol(-1 in April-May, two or three times as high as those in March. Stepwise multiple linear regressions showed that P max increased with the increase in leaf area index (LAI, canopy conductance (g c and air temperature (T a but declined with increasing vapor pressure deficit (VPD (P25°C or VPD>1.1-1.3 kPa, NEE residual increased with the increase in T a and VPD (P<0.001, indicating that temperature and water stress occurred. When g c was more than 14 mm s(-1 in March and May and 26 mm s(-1 in April, the NEE residuals decline disappeared, or even turned into an increase in g c (P<0.01, implying shifts from stomatal limitation to non-stomatal limitation on NEE. Although the differences between sunny and cloudy sky conditions were unremarkable for light response parameters, simulated net CO2 uptake under the same radiation intensity averaged 18% higher in cloudy days than in sunny days during the year 2003-2006. It is necessary to include these effects in relevant carbon cycle models to improve our estimation of carbon balance at regional and global scales.

  6. Nanoscale quantification of the biophysical characterization of combretastatin A-4-treated tumor cells using atomic force microscopy.

    Science.gov (United States)

    Li, Yanchun; Chen, Jv; Liu, Yutong; Zhang, Weige; He, Wenhui; Xu, Hanying; Liu, Lianqing; Ma, Enlong

    2017-01-01

    As an inhibitor of microtubule assembly, combretastatin A-4 (CA-4)-induced biological responses in tumor cells have been well known, but the corresponding changes in nano-biophysical properties were not investigated given the lack of an ideal tool. Using AFM technique, we investigated the alteration of nano-biophysical properties when CA-4-treated tumor cells underwent the different biological processes, including cell cycle arrest, apoptosis and autophagy. We found that CA-4-resistant cells were rougher with the presence of characteristic "ridges", indicating that the development of "ridge" structure may be a determinant of the sensitivity of cells to CA-4 compounds. CA-4 induced G2/M arrest and apoptosis in sensitive cells but triggered anti-apoptotic autophagy in resistant cells. CA-4 treatment caused an increase in stiffness in both sensitive and resistant cells. However, these cells exhibited different changes in cell surface roughness. CA-4 decreased Ra and Rq values in sensitive cells but increased these values in resistant cells. The reorganization of F-actin might contribute to the different changes of nano-biophysical properties in CA-4-sensitive and-resistant cells. Our results suggest that cellular nano-biophysical properties, such as "ridges", roughness and stiffness, could be applied as potential biomarkers for evaluating CA-4 compounds, and knowledge regarding how biological alterations cause changes in cellular nano-biophysical properties is helpful to develop a new high-resolution screening tool for anti-tumor agents.

  7. Selection of Hyperspectral Narrowbands (HNBs) and Composition of Hyperspectral Twoband Vegetation Indices (HVIs) for Biophysical Characterization and Discrimination of Crop Types Using Field Reflectance and Hyperion-EO-1 Data

    Science.gov (United States)

    Thenkabail, Prasad S.; Mariotto, Isabella; Gumma, Murali Krishna; Middleton, Elizabeth M.; Landis, David R.; Huemmrich, K. Fred

    2013-01-01

    .g., biophysical characterization of crops). The findings of this study will make a significant contribution to future hyperspectral missions such as NASA's HyspIRI. Index Terms-Hyperion, field reflectance, imaging spectroscopy, HyspIRI, biophysical parameters, hyperspectral vegetation indices, hyperspectral narrowbands, broadbands.

  8. Emergy analysis of a farm biogas project in China: A biophysical perspective of agricultural ecological engineering

    Science.gov (United States)

    Zhou, S. Y.; Zhang, B.; Cai, Z. F.

    2010-05-01

    This paper aims to present a biophysical understanding of the agricultural ecological engineering by emergy analysis for a farm biogas project in China as a representative case. Accounting for the resource inputs into and accumulation within the project, as well as the outputs to the social system, emergy analysis provides an empirical study in the biophysical dimension of the agricultural ecological engineering. Economic benefits and ecological economic benefits of the farm biogas project indicated by market value and emergy monetary value are discussed, respectively. Relative emergy-based indices such as renewability (R%), emergy yield ratio (EYR), environmental load ratio (ELR) and environmental sustainability index (ESI) are calculated to evaluate the environmental load and local sustainability of the concerned biogas project. The results show that the farm biogas project has more reliance on the local renewable resources input, less environmental pressure and higher sustainability compared with other typical agricultural systems. In addition, holistic evaluation and its policy implications for better operation and management of the biogas project are presented.

  9. Guidance for Large-scale Implementation of Alternate Wetting and Drying: A Biophysical Suitability Assessment

    Science.gov (United States)

    Sander, B. O.; Wassmann, R.; Nelson, A.; Palao, L.; Wollenberg, E.; Ishitani, M.

    2014-12-01

    The alternate wetting and drying (AWD) technology for rice production does not only save 15-30% of irrigation water, it also reduces methane emissions by up to 70%. AWD is defined by periodic drying and re-flooding of a rice field. Due to its high mitigation potential and its simplicity to execute this practice AWD has gained a lot of attention in recent years. The Climate and Clean Air Coalition (CCAC) has put AWD high on its agenda and funds a project to guide implementation of this technology in Vietnam, Bangladesh and Colombia. One crucial activity is a biophysical suitability assessment for AWD in the three countries. For this, we analyzed rainfall and soil data as well as potential evapotranspiration to assess if the water balance allows practicing AWD or if precipitation is too high for rice fields to fall dry. In my talk I will outline key factors for a successful large-scale implementation of AWD with a focus on the biophysical suitability assessment. The seasonal suitability maps that we generated highlight priority areas for AWD implementation and guide policy makers to informed decisions about meaningful investments in infrastructure and extension work.

  10. An ultra-sensitive biophysical risk assessment of light effect on skin cells.

    Science.gov (United States)

    Bennet, Devasier; Viswanath, Buddolla; Kim, Sanghyo; An, Jeong Ho

    2017-07-18

    The aim of this study was to analyze photo-dynamic and photo-pathology changes of different color light radiations on human adult skin cells. We used a real-time biophysical and biomechanics monitoring system for light-induced cellular changes in an in vitro model to find mechanisms of the initial and continuous degenerative process. Cells were exposed to intermittent, mild and intense (1-180 min) light with On/Off cycles, using blue, green, red and white light. Cellular ultra-structural changes, damages, and ECM impair function were evaluated by up/down-regulation of biophysical, biomechanical and biochemical properties. All cells exposed to different color light radiation showed significant changes in a time-dependent manner. Particularly, cell growth, stiffness, roughness, cytoskeletal integrity and ECM proteins of the human dermal fibroblasts-adult (HDF-a) cells showed highest alteration, followed by human epidermal keratinocytes-adult (HEK-a) cells and human epidermal melanocytes-adult (HEM-a) cells. Such changes might impede the normal cellular functions. Overall, the obtained results identify a new insight that may contribute to premature aging, and causes it to look aged in younger people. Moreover, these results advance our understanding of the different color light-induced degenerative process and help the development of new therapeutic strategies.

  11. Biophysical and biochemical constraints imposed by salt stress:Learning from halophyte

    Directory of Open Access Journals (Sweden)

    Bernardo eDuarte

    2014-12-01

    Full Text Available Soil salinization is one of the most important factors impacting plant productivity. About 3.6 billion of the world’s 5.2 billion ha of agricultural dryland have already suffered erosion, degradation and salinization. Halophytes typically are considered as plants able to complete their life cycle in environments where the salt concentration is 200 mM NaCl or higher. Different strategies are known to overcome salt stress, as adaptation mechanisms from this type of plants. Salinity adjustment is a complex phenomenon characterized by both biochemical and biophysical adaptations. As photosynthesis is a prerequisite for biomass production, halophytes adapted their electronic transduction pathways and the entire energetic metabolism to overcome the salt excess. The maintenance of ionic homeostasis is in the basis of all cellular stress in particular in terms of redox potential and energy transduction. In the present work the biophysical mechanisms underlying energy capture and transduction in halophytes are discussed alongside with their relation to biochemical mechanisms, integrating data from photosystem light harvesting complexes, electronic transport chains to the quinone pools, carbon harvesting and energy dissipation metabolism.

  12. Synergistic linkage between remote sensing and biophysical models for estimating plant ecophysiological and ecosystem processes

    International Nuclear Information System (INIS)

    Inoue, Y.; Olioso, A.

    2004-01-01

    Abstract Information on the ecological and physiological status of crops is essential for growth diagnostics and yield prediction. Within-field or between-field spatial information is required, especially with the recent trend toward precision agriculture, which seeks the efficient use of agrochemicals, water, and energy. The study of carbon and nitrogen cycles as well as environmental management on local and regional scales requires assessment of the spatial variability of biophysical and ecophysiological variables, scaling up of which is also needed for scientific and decision-making purposes. Remote sensing has great potential for these applications because it enables wide-area non-destructive, and real-time acquisition of information about ecophysiological conditions of vegetation. With recent advances in sensor technology, a variety of electromagnetic signatures, such as hyperspectral reflectance, thermal-infrared temperature, and microwave backscattering coefficients, can be acquired for both plants and ecosystems using ground-based, airborne, and satellite platforms. Their spatial and temporal resolutions have both recently been improved. This article reviews the state of the art in the remote sensing of plant ecophysiological data, with special emphasis on the synergy between remote sensing signatures and biophysical and ecophysiological process models. Several case studies for the optical, thermal, and microwave domains have demonstrated the potential of this synergistic linkage. Remote sensing and process modeling methods complement each other when combined synergistically. Further research on this approach is needed f or a wide range of ecophysiological and ecosystem studies, as well as for practical crop management

  13. Interactive Biophysics with Microswimmers: Education, Cloud Experimentation, Programmed Swarms, and Biotic Games

    Science.gov (United States)

    Riedel-Kruse, Ingmar

    Modern biotechnology gets increasingly powerful to manipulate and measure microscopic biophysical processes. Nevertheless, no platform exists to truly interact with these processes, certainly not with the convenience that we are accustomed to from our electronic smart devices. In my talk I will provide the rational for such Interactive Biotechnology and conceptualize its core component, the BPU (biotic processing unit), which is then connected to an according user interface. The biophysical phenomena currently featured on these platforms utilize the phototactic response of motile microorganisms, e.g., Euglena gracilis, resulting in spatio-temporal dynamics from the single cell to the self-organized multi-cellular scale. I will demonstrate multiple platforms, such as scalable biology cloud experimentation labs, tangible museum exhibits, biotic video games, low-cost interactive DIY kits using smartphones, and programming languages for swarm robotics. I will discuss applications for education as well as for professional and citizen science. Hence, we turn traditionally observational microscopy into an interactive experience. I was told that presenting in the educational section does not count against the ''one author - one talk policy'' - so I submit two abstracts. In case of conflict - please contact me: ingmar@stanford.edu.

  14. Mesenchymal stem cells as therapeutic target of biophysical stimulation for the treatment of musculoskeletal disorders.

    Science.gov (United States)

    Viganò, Marco; Sansone, Valerio; d'Agostino, Maria Cristina; Romeo, Pietro; Perucca Orfei, Carlotta; de Girolamo, Laura

    2016-12-16

    Musculoskeletal disorders are regarded as a major cause of worldwide morbidity and disability, and they result in huge costs for national health care systems. Traditional therapies frequently turned out to be poorly effective in treating bone, cartilage, and tendon disorders or joint degeneration. As a consequence, the development of novel biological therapies that can treat more effectively these conditions should be the highest priority in regenerative medicine. Mesenchymal stem cells (MSCs) represent one of the most promising tools in musculoskeletal tissue regenerative medicine, thanks to their proliferation and differentiation potential and their immunomodulatory and trophic ability. Indeed, MSC-based approaches have been proposed for the treatment of almost all orthopedic conditions, starting from different cell sources, alone or in combination with scaffolds and growth factors, and in one-step or two-step procedures. While all these approaches would require cell harvesting and transplantation, the possibility to stimulate the endogenous MSCs to enhance their tissue homeostasis activity represents a less-invasive and cost-effective therapeutic strategy. Nowadays, the role of tissue-specific resident stem cells as possible therapeutic target in degenerative pathologies is underinvestigated. Biophysical stimulations, and in particular extracorporeal shock waves treatment and pulsed electromagnetic fields, are able to induce proliferation and support differentiation of MSCs from different origins and affect their paracrine production of growth factors and cytokines. The present review reports the attempts to exploit the resident stem cell potential in musculoskeletal pathologies, highlighting the role of MSCs as therapeutic target of currently applied biophysical treatments.

  15. On the biophysics and kinetics of toehold-mediated DNA strand displacement.

    Science.gov (United States)

    Srinivas, Niranjan; Ouldridge, Thomas E; Sulc, Petr; Schaeffer, Joseph M; Yurke, Bernard; Louis, Ard A; Doye, Jonathan P K; Winfree, Erik

    2013-12-01

    Dynamic DNA nanotechnology often uses toehold-mediated strand displacement for controlling reaction kinetics. Although the dependence of strand displacement kinetics on toehold length has been experimentally characterized and phenomenologically modeled, detailed biophysical understanding has remained elusive. Here, we study strand displacement at multiple levels of detail, using an intuitive model of a random walk on a 1D energy landscape, a secondary structure kinetics model with single base-pair steps and a coarse-grained molecular model that incorporates 3D geometric and steric effects. Further, we experimentally investigate the thermodynamics of three-way branch migration. Two factors explain the dependence of strand displacement kinetics on toehold length: (i) the physical process by which a single step of branch migration occurs is significantly slower than the fraying of a single base pair and (ii) initiating branch migration incurs a thermodynamic penalty, not captured by state-of-the-art nearest neighbor models of DNA, due to the additional overhang it engenders at the junction. Our findings are consistent with previously measured or inferred rates for hybridization, fraying and branch migration, and they provide a biophysical explanation of strand displacement kinetics. Our work paves the way for accurate modeling of strand displacement cascades, which would facilitate the simulation and construction of more complex molecular systems.

  16. Biophysics environmental conditions of swamp buffalo Bubalus bubalis Pampangan in district Rambutan South Sumatera

    Directory of Open Access Journals (Sweden)

    Yuanita Windusari

    2015-06-01

    Full Text Available Swamp buffalo (Bubalus bubalis is a germ plasm specific of Pampangan and endemic in South Sumatera with low productivity and limited distribution. The aims of this study was to obtain information regarding biophysical conditions in the central areas of swamp buffalo in South Sumatera. The method used is purposive sampling method. Data collected in the form of quantitative and qualitative. Primary data were obtained through direct observation, interviews breeders selected as respondents while secondary data obtained from various related. The data obtained are presented descriptively and data tabulation. Productivity of swamp buffalo Pampangan can be increased by managing and maintaining habitat conditions although traditional maintenance. The results of observations of the biophysical condition of swamp buffalo (B. bubalis Pampangan showed that habitat of swamp buffalo Pampangan consists of dominated by lowland swamp area is overgrown with shrubs and grass. The conclution of the research are productivity and population of swamp buffalo (B. bubalis pampangan as specific plasma nutfah of South Sumatra can be improved by studying the characteristics and preferred habitat of the buffalo, although developed in a traditional farms but is good enough and so need to be developed, grass is most preferred by swamp buffalo Pampangan derived from ‘Kumpai’ grass group, and ‘Kasur’grass and ‘Kumpai’ grass is the dominant grass type found in habitat swamp buffalo Pampangan.

  17. Contributions of computational chemistry and biophysical techniques to fragment-based drug discovery.

    Science.gov (United States)

    Gozalbes, Rafael; Carbajo, Rodrigo J; Pineda-Lucena, Antonio

    2010-01-01

    In the last decade, fragment-based drug discovery (FBDD) has evolved from a novel approach in the search of new hits to a valuable alternative to the high-throughput screening (HTS) campaigns of many pharmaceutical companies. The increasing relevance of FBDD in the drug discovery universe has been concomitant with an implementation of the biophysical techniques used for the detection of weak inhibitors, e.g. NMR, X-ray crystallography or surface plasmon resonance (SPR). At the same time, computational approaches have also been progressively incorporated into the FBDD process and nowadays several computational tools are available. These stretch from the filtering of huge chemical databases in order to build fragment-focused libraries comprising compounds with adequate physicochemical properties, to more evolved models based on different in silico methods such as docking, pharmacophore modelling, QSAR and virtual screening. In this paper we will review the parallel evolution and complementarities of biophysical techniques and computational methods, providing some representative examples of drug discovery success stories by using FBDD.

  18. New generation non-stationary portable neutron generators for biophysical applications of Neutron Activation Analysis.

    Science.gov (United States)

    Marchese, N; Cannuli, A; Caccamo, M T; Pace, C

    2017-01-01

    Neutron sources are increasingly employed in a wide range of research fields. For some specific purposes an alternative to existing large-scale neutron scattering facilities, can be offered by the new generation of portable neutron devices. This review reports an overview for such recently available neutron generators mainly addressed to biophysics applications with specific reference to portable non-stationary neutron generators applied in Neutron Activation Analysis (NAA). The review reports a description of a typical portable neutron generator set-up addressed to biophysics applications. New generation portable neutron devices, for some specific applications, can constitute an alternative to existing large-scale neutron scattering facilities. Deuterium-Deuterium pulsed neutron sources able to generate 2.5MeV neutrons, with a neutron yield of 1.0×10 6 n/s, a pulse rate of 250Hz to 20kHz and a duty factor varying from 5% to 100%, when combined with solid-state photon detectors, show that this kind of compact devices allow rapid and user-friendly elemental analysis. "This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo". Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Reduction of Radiation-Induced Changes in Biophysical Properties of Erythrocytes

    International Nuclear Information System (INIS)

    El-Marakby, S.M.A.

    2014-01-01

    The increase in uses of nuclear technologies in power production, medical and industrial applications enhanced the probability of accidental radiation exposure to occupational workers, patients and public, thereafter increasing hazardous health effects. In comparison with planned radiation exposure during diagnosis and therapy, the management of accidental radiation exposure is relatively complicated due to uncertainties in dose, duration, organs involved in radiation exposure. Although radiation accidents are not common, human error, failure to follow safety precautions and inadequate control and regulation of radiation sources have led to deaths and significant exposures among workers and members of the public. Treatment of the victim in this case needs information and measurements that may take time in order to determine the suitable therapeutic strategy for its case. However, after the event of the radiation accident, it will be important to provide an agent that would mitigate the effects of exposure to ionizing radiation and can promote or increase the efficiency of the treatment. Ideally this agent would be long-lasting, be easily administered (preferably orally) and possesses low toxicity. Development of agents for prophylaxis, mitigation and treatment of radiation injury is an important task for radiological studies. The aim of the present work is to study the prophylactic and mitigation effect of poly-MVA (a dietary supplement of Palladiumlipoic acid nano-complex) against acute whole body gamma irradiation through measurements of biophysical changes in blood erythrocytes of rats. Adult male rats were exposed to 6 Gy single dose from Cs- 137 source. The animals received daily oral administration of 2ml/Kg body weight of poly-MVA with three different time intervals. The prophylactic effect was examined by two modes of administration: first mode was uptake of poly-MVA for two weeks before irradiation then the administration was stopped and the second animal

  20. The Nexus Land-Use model version 1.0, an approach articulating biophysical potentials and economic dynamics to model competition for land-use

    Science.gov (United States)

    Souty, F.; Brunelle, T.; Dumas, P.; Dorin, B.; Ciais, P.; Crassous, R.; Müller, C.; Bondeau, A.

    2012-10-01

    Interactions between food demand, biomass energy and forest preservation are driving both food prices and land-use changes, regionally and globally. This study presents a new model called Nexus Land-Use version 1.0 which describes these interactions through a generic representation of agricultural intensification mechanisms within agricultural lands. The Nexus Land-Use model equations combine biophysics and economics into a single coherent framework to calculate crop yields, food prices, and resulting pasture and cropland areas within 12 regions inter-connected with each other by international trade. The representation of cropland and livestock production systems in each region relies on three components: (i) a biomass production function derived from the crop yield response function to inputs such as industrial fertilisers; (ii) a detailed representation of the livestock production system subdivided into an intensive and an extensive component, and (iii) a spatially explicit distribution of potential (maximal) crop yields prescribed from the Lund-Postdam-Jena global vegetation model for managed Land (LPJmL). The economic principles governing decisions about land-use and intensification are adapted from the Ricardian rent theory, assuming cost minimisation for farmers. In contrast to the other land-use models linking economy and biophysics, crops are aggregated as a representative product in calories and intensification for the representative crop is a non-linear function of chemical inputs. The model equations and parameter values are first described in details. Then, idealised scenarios exploring the impact of forest preservation policies or rising energy price on agricultural intensification are described, and their impacts on pasture and cropland areas are investigated.

  1. The Nexus Land-Use model version 1.0, an approach articulating biophysical potentials and economic dynamics to model competition for land-use

    Directory of Open Access Journals (Sweden)

    F. Souty

    2012-10-01

    Full Text Available Interactions between food demand, biomass energy and forest preservation are driving both food prices and land-use changes, regionally and globally. This study presents a new model called Nexus Land-Use version 1.0 which describes these interactions through a generic representation of agricultural intensification mechanisms within agricultural lands. The Nexus Land-Use model equations combine biophysics and economics into a single coherent framework to calculate crop yields, food prices, and resulting pasture and cropland areas within 12 regions inter-connected with each other by international trade. The representation of cropland and livestock production systems in each region relies on three components: (i a biomass production function derived from the crop yield response function to inputs such as industrial fertilisers; (ii a detailed representation of the livestock production system subdivided into an intensive and an extensive component, and (iii a spatially explicit distribution of potential (maximal crop yields prescribed from the Lund-Postdam-Jena global vegetation model for managed Land (LPJmL. The economic principles governing decisions about land-use and intensification are adapted from the Ricardian rent theory, assuming cost minimisation for farmers. In contrast to the other land-use models linking economy and biophysics, crops are aggregated as a representative product in calories and intensification for the representative crop is a non-linear function of chemical inputs. The model equations and parameter values are first described in details. Then, idealised scenarios exploring the impact of forest preservation policies or rising energy price on agricultural intensification are described, and their impacts on pasture and cropland areas are investigated.

  2. Closing Yield Gaps: How Sustainable Can We Be?

    Directory of Open Access Journals (Sweden)

    Prajal Pradhan

    Full Text Available Global food production needs to be increased by 60-110% between 2005 and 2050 to meet growing food and feed demand. Intensification and/or expansion of agriculture are the two main options available to meet the growing crop demands. Land conversion to expand cultivated land increases GHG emissions and impacts biodiversity and ecosystem services. Closing yield gaps to attain potential yields may be a viable option to increase the global crop production. Traditional methods of agricultural intensification often have negative externalities. Therefore, there is a need to explore location-specific methods of sustainable agricultural intensification. We identified regions where the achievement of potential crop calorie production on currently cultivated land will meet the present and future food demand based on scenario analyses considering population growth and changes in dietary habits. By closing yield gaps in the current irrigated and rain-fed cultivated land, about 24% and 80% more crop calories can respectively be produced compared to 2000. Most countries will reach food self-sufficiency or improve their current food self-sufficiency levels if potential crop production levels are achieved. As a novel approach, we defined specific input and agricultural management strategies required to achieve the potential production by overcoming biophysical and socioeconomic constraints causing yield gaps. The management strategies include: fertilizers, pesticides, advanced soil management, land improvement, management strategies coping with weather induced yield variability, and improving market accessibility. Finally, we estimated the required fertilizers (N, P2O5, and K2O to attain the potential yields. Globally, N-fertilizer application needs to increase by 45-73%, P2O5-fertilizer by 22-46%, and K2O-fertilizer by 2-3 times compared to the year 2010 to attain potential crop production. The sustainability of such agricultural intensification largely depends

  3. Closing Yield Gaps: How Sustainable Can We Be?

    Science.gov (United States)

    Pradhan, Prajal; Fischer, Günther; van Velthuizen, Harrij; Reusser, Dominik E.; Kropp, Juergen P.

    2015-01-01

    Global food production needs to be increased by 60–110% between 2005 and 2050 to meet growing food and feed demand. Intensification and/or expansion of agriculture are the two main options available to meet the growing crop demands. Land conversion to expand cultivated land increases GHG emissions and impacts biodiversity and ecosystem services. Closing yield gaps to attain potential yields may be a viable option to increase the global crop production. Traditional methods of agricultural intensification often have negative externalities. Therefore, there is a need to explore location-specific methods of sustainable agricultural intensification. We identified regions where the achievement of potential crop calorie production on currently cultivated land will meet the present and future food demand based on scenario analyses considering population growth and changes in dietary habits. By closing yield gaps in the current irrigated and rain-fed cultivated land, about 24% and 80% more crop calories can respectively be produced compared to 2000. Most countries will reach food self-sufficiency or improve their current food self-sufficiency levels if potential crop production levels are achieved. As a novel approach, we defined specific input and agricultural management strategies required to achieve the potential production by overcoming biophysical and socioeconomic constraints causing yield gaps. The management strategies include: fertilizers, pesticides, advanced soil management, land improvement, management strategies coping with weather induced yield variability, and improving market accessibility. Finally, we estimated the required fertilizers (N, P2O5, and K2O) to attain the potential yields. Globally, N-fertilizer application needs to increase by 45–73%, P2O5-fertilizer by 22–46%, and K2O-fertilizer by 2–3 times compared to the year 2010 to attain potential crop production. The sustainability of such agricultural intensification largely depends on the way

  4. Grassland canopy parameters and their relationships to remotely sensed vegetation indices in the Nebraska Sand Hills

    Science.gov (United States)

    Wylie, Bruce K.; DeJong, Donovan D.; Tieszen, Larry L.; Biondini, Mario E.

    1996-01-01

    Relationships among spectral vegetation indices and grassland biophysical parameters including the effects of varying levels of standing dead vegetation, range sites, and range plant communities were examined. Range plant communities consisting of northern mixed grass prairie and a smooth brome field as well as range sites and management in a Sand Hills bluestem prairie were sampled with a ground radiometer and for LAI, biomass, chlorophy

  5. BLM Colorado Mining Claims Closed

    Data.gov (United States)

    Department of the Interior — Shapefile Format –This data set consists of closed mining claim records extracted from BLM’s LR2000 database. These records contain case attributes as well as legal...

  6. Pollution hazard closes neutrino lab

    CERN Multimedia

    Jones, Nicola

    2003-01-01

    "A leading astrophysics laboratory in Italy has closed down all but one of its experiments over concerns that toxic polluants could leak form the underground lab into the local water supply" (0.5 page)

  7. [Correlation analysis between biochemical and biophysical markers of endothelium damage in children with diabetes type 1].

    Science.gov (United States)

    Głowińska-Olszewska, Barbara; Urban, Mirosława; Tołwińska, Joanna; Peczyńska, Jadwiga; Florys, Bozena

    2005-01-01

    Endothelial damage is one of the earliest stages in the atherosclerosis process. Adhesion molecules, secreted from dysfunctional endothelial cells are considered as early markers of atherosclerotic disease. Ultrasonographic evaluation of brachial arteries serves to detect biophysical changes in endothelial function, and evaluation of carotid arteries intima-media thickness allows to evaluate the earliest structural changes in the vessels. The aim of the study was to the evaluate levels of selected adhesion molecules (sICAM-1, sVCAM-1, sE-selectin, sP-selectin) and endothelial function with use of brachial artery dilatation study (flow mediated dilation--FMD, nitroglycerine mediated dilation--NTGMD) and IMT in carotid arteries in children and adolescents with diabetes type 1, as well as the correlation analysis between biochemical and biophysical markers of endothelial dysfunction. We studied 76 children and adolescents, with mean age--15.6+/-2.5 years, suffering from diabetes mean 7.8+/-2.8 years, mean HbA1c--8.4+/-1.5%. Control group consisted of 33 healthy children age and gender matched. Adhesion molecules levels were estimated with the use of immunoenzymatic methods (R&D Systems). Endothelial function was evaluated by study of brachial arteries dilation--FMD, NTGMD, with ultrasonographic evaluation (Hewlett Packard Sonos 4500) after Celermajer method, and IMT after Pignoli method. In the study group we found elevated levels of sICAM-1: 309.54+/-64 vs. 277.85+/-52 ng/ml in the control group (p<00.05) and elevated level of sE-selectin: 87.81+/-35 vs. 66.21+/-22 ng/ml (p<00.05). We found significantly impaired FMD in brachial arteries in the study group--7.51+/-4.52 vs. 12.61+/-4.65% (p<00.05) and significantly higher IMT value: 0.51+/-0.07 vs. 0.42+/-0.05 mm (p<00.001). Correlation analysis revealed a significant negative correlation between sE-selectin and FMD - r=-0.33 (p=0.004), and a positive correlation between E-selectin and IMT: r=0.32 (p=0.005). 1. In

  8. Closed recirculation-Water treatment

    International Nuclear Information System (INIS)

    Hamza, Hamza B.; Ben Ali, Salah; Saad, Mohamed A.; Traish, Massud R.

    2005-01-01

    This water treatment is a practical work applied in the center, for a closed recirculation-water system. The system had experienced a serious corrosion problem, due to the use of inadequate water. This work includes chemical preparation for the system. Water treatment, special additives, and follow-up, which resulted in the stability of the case. This work can be applied specially for closed recirculation warm, normal, and chilled water. (author)

  9. Judging Criterion of Controlled Structures with Closely Spaced Natural Frequencies

    International Nuclear Information System (INIS)

    Xie Faxiang; Sun Limin

    2010-01-01

    The structures with closely spaced natural frequencies widely exist in civil engineering; however, the judging criterion of the density of closely spaced frequencies is in dispute. This paper suggests a judging criterion for structures with closely spaced natural frequencies based on the analysis on a controlled 2-DOF structure. The analysis results indicate that the optimal control gain of the structure with velocity feedback is dependent on the frequency density parameter of structure and the maximum attainable additional modal damping ratio is 1.72 times of the frequency density parameter when state feedback is applied. Based on a brief review on the previous researches, a judging criterion related the minimum frequency density parameter and the required mode damping ratio was proposed.

  10. Respiratory diagnostic possibilities during closed circuit anesthesia.

    Science.gov (United States)

    Verkaaik, A P; Erdmann, W

    1990-01-01

    An automatic feed back controlled totally closed circuit system (Physioflex) has been developed for quantitative practice of inhalation anesthesia and ventilation. In the circuit system the gas is moved unidirectionally around by a blower at 70 l/min. In the system four membrane chambers are integrated for ventilation. Besides end-expiratory feed back control of inhalation anesthetics, and inspiratory closed loop control of oxygen, the system offers on-line registration of flow, volume and respiratory pressures as well as a capnogram and oxygen consumption. Alveolar ventilation and static compliance can easily be derived. On-line registration of oxygen consumption has proven to be of value for determination of any impairment of tissue oxygen supply when the oxygen delivery has dropped to critical values. Obstruction of the upper or lower airways are immediately detected and differentiated. Disregulations of metabolism, e.g. in malignant hyperthermia, are seen in a pre-crisis phase (increase of oxygen consumption and of CO2 production), and therapy can be started extremely early and before a disastrous condition has developed. Registration of compliance is only one of the continuously available parameters that guarantee a better and adequate control of lung function (e.g. atalectasis is early detected). The newly developed sophisticated anesthesia device enlarges tremendously the monitoring and respiratory diagnostic possibilities of artificial ventilation, gives new insights in the (patho)physiology and detects disturbances of respiratory parameters and metabolism in an early stage.

  11. Using biophysical models to manage nitrogen pollution from agricultural sources: Utopic or realistic approach for non-scientist users? Case study of a drinking water catchment area in Lorraine, France.

    Science.gov (United States)

    Bernard, Pierre-Yves; Benoît, Marc; Roger-Estrade, Jean; Plantureux, Sylvain

    2016-12-01

    The objectives of this comparison of two biophysical models of nitrogen losses were to evaluate first whether results were similar and second whether both were equally practical for use by non-scientist users. Results were obtained with the crop model STICS and the environmental model AGRIFLUX based on nitrogen loss simulations across a small groundwater catchment area (<1 km(2)) located in the Lorraine region in France. Both models simulate the influences of leaching and cropping systems on nitrogen losses in a relevant manner. The authors conclude that limiting the simulations to areas where soils with a greater risk of leaching cover a significant spatial extent would likely yield acceptable results because those soils have more predictable leaching of nitrogen. In addition, the choice of an environmental model such as AGRIFLUX which requires fewer parameters and input variables seems more user-friendly for agro-environmental assessment. The authors then discuss additional challenges for non-scientists such as lack of parameter optimization, which is essential to accurately assessing nitrogen fluxes and indirectly not to limit the diversity of uses of simulated results. Despite current restrictions, with some improvement, biophysical models could become useful environmental assessment tools for non-scientists. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Abstracts of the 9. Brazilian Congress of Biophysics, 2. Brazilian Congress of Pharmacology and Experimental Therapeutics and 19. Brazilian Congress of Physiology

    International Nuclear Information System (INIS)

    1984-01-01

    Abstracts about biophysics, pharmacology, experimental therapeutics and physiology are presented. The use of radioisotopes in radioassays involve topics like biophysics and renal physiology; central nervous system; endocrinology; animal and comparative physiology; general physiology, digestion and nutrition; general pharmacology. (M.A.C.) [pt

  13. Asymptotics of elliptic and parabolic pdes and their applications in statistical physics, computational neuroscience, and biophysics

    CERN Document Server

    Holcman, David

    2018-01-01

    This is a monograph on the emerging branch of mathematical biophysics combining asymptotic analysis with numerical and stochastic methods to analyze partial differential equations arising in biological and physical sciences. In more detail, the book presents the analytic methods and tools for approximating solutions of mixed boundary value problems, with particular emphasis on the narrow escape problem. Informed throughout by real-world applications, the book includes topics such as the Fokker-Planck equation, boundary layer analysis, WKB approximation, applications of spectral theory, as well as recent results in narrow escape theory. Numerical and stochastic aspects, including mean first passage time and extreme statistics, are discussed in detail and relevant applications are presented in parallel with the theory. Including background on the classical asymptotic theory of differential equations, this book is written for scientists of various backgrounds interested in deriving solutions to real-world proble...

  14. Diffusion-weighted MRI and quantitative biophysical modeling of hippocampal neurite loss in chronic stress.

    Directory of Open Access Journals (Sweden)

    Peter Vestergaard-Poulsen

    Full Text Available Chronic stress has detrimental effects on physiology, learning and memory and is involved in the development of anxiety and depressive disorders. Besides changes in synaptic formation and neurogenesis, chronic stress also induces dendritic remodeling in the hippocampus, amygdala and the prefrontal cortex. Investigations of dendritic remodeling during development and treatment of stress are currently limited by the invasive nature of histological and stereological methods. Here we show that high field diffusion-weighted MRI combined with quantitative biophysical modeling of the hippocampal dendritic loss in 21 day restraint stressed rats highly correlates with former histological findings. Our study strongly indicates that diffusion-weighted MRI is sensitive to regional dendritic loss and thus a promising candidate for non-invasive studies of dendritic plasticity in chronic stress and stress-related disorders.

  15. Lessons from the biophysics of interfaces: Lung surfactant and tear fluid

    DEFF Research Database (Denmark)

    Rantamaki, A.; Telenius, J.; Koivuniemi, A.

    2011-01-01

    The purpose of this review is to provide insight into the biophysical properties and functions of tear fluid and lung surfactant - two similar fluids covering the epithelium of two distinctive organs. Both fluids form a layer-like structure that essentially comprise of an aqueous layer next......-active function of the fluid film. The lipid layer of lung surfactant comprises mainly of phospholipids, especially phosphatidylcholines, and only small amounts of non-polar lipids, mainly cholesterol. In contrast, tear fluid lipid layer comprises of a mixture of polar and non-polar lipids. However, the relative...... proportion and the spectrum of different polar and non-polar lipids seem to be more extensive in tear fluid than in lung surfactant. The differing lipid compositions generate distinctive lipid layer structures. Despite the structural differences, these lipid layers decrease the surface tension of the air...

  16. The Physics of Proteins An Introduction to Biological Physics and Molecular Biophysics

    CERN Document Server

    Frauenfelder, Hans; Chan, Winnie S

    2010-01-01

    Physics and the life sciences have established new connections within the past few decades, resulting in biological physics as an established subfield with strong groups working in many physics departments. These interactions between physics and biology form a two-way street with physics providing new tools and concepts for understanding life, while biological systems can yield new insights into the physics of complex systems. To address the challenges of this interdisciplinary area, The Physics of Proteins: An Introduction to Biological Physics and Molecular Biophysics is divided into three interconnected sections. In Parts I and II, early chapters introduce the terminology and describe the main biological systems that physicists will encounter. Similarities between biomolecules, glasses, and solids are stressed with an emphasis on the fundamental concepts of living systems. The central section (Parts III and IV) delves into the dynamics of complex systems. A main theme is the realization that biological sys...

  17. Biophysics of DNA-Protein Interactions From Single Molecules to Biological Systems

    CERN Document Server

    Williams, Mark C

    2011-01-01

    This book presents a concise overview of current research on the biophysics of DNA-protein interactions. A wide range of new and classical methods are presented by authors investigating physical mechanisms by which proteins interact with DNA. For example, several chapters address the mechanisms by which proteins search for and recognize specific binding sites on DNA, a process critical for cellular function. Single molecule methods such as force spectroscopy as well as fluorescence imaging and tracking are described in these chapters as well as other parts of the book that address the dynamics of protein-DNA interactions. Other important topics include the mechanisms by which proteins engage DNA sequences and/or alter DNA structure. These simple but important model interactions are then placed in the broader biological context with discussion of larger protein-DNA complexes . Topics include replication forks, recombination complexes, DNA repair interactions, and ultimately, methods to understand the chromatin...

  18. Summaries of research projects for fiscal years 1996 and 1997, medical applications and biophysical research

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-02-01

    The Medical Applications and Biophysical Research Division of the Office of Biological and Environmental Research supports and manages research in several distinct areas of science and technology. The projects described in this book are grouped by the main budgetary areas: General Life Sciences (structural molecular biology), Medical Applications (primarily nuclear medicine) and Measurement Science (analytical chemistry instrumentation), Environmental Management Science Program, and the Small Business Innovation Research Program. The research funded by this division complements that of the other two divisions in the Office of Biological and Environmental Research (OBER): Health Effects and Life Sciences Research, and Environmental Sciences. Most of the OBER programs are planned and administered jointly by the staff of two or all three of the divisions. This summary book provides information on research supported in these program areas during Fiscal Years 1996 and 1997.

  19. Computer Simulation and Data Analysis in Molecular Biology and Biophysics An Introduction Using R

    CERN Document Server

    Bloomfield, Victor

    2009-01-01

    This book provides an introduction, suitable for advanced undergraduates and beginning graduate students, to two important aspects of molecular biology and biophysics: computer simulation and data analysis. It introduces tools to enable readers to learn and use fundamental methods for constructing quantitative models of biological mechanisms, both deterministic and with some elements of randomness, including complex reaction equilibria and kinetics, population models, and regulation of metabolism and development; to understand how concepts of probability can help in explaining important features of DNA sequences; and to apply a useful set of statistical methods to analysis of experimental data from spectroscopic, genomic, and proteomic sources. These quantitative tools are implemented using the free, open source software program R. R provides an excellent environment for general numerical and statistical computing and graphics, with capabilities similar to Matlab®. Since R is increasingly used in bioinformat...

  20. Structure-function relationships in pulmonary surfactant membranes: from biophysics to therapy.

    Science.gov (United States)

    Lopez-Rodriguez, Elena; Pérez-Gil, Jesús

    2014-06-01

    Pulmonary surfactant is an essential lipid-protein complex to maintain an operative respiratory surface at the mammalian lungs. It reduces surface tension at the alveolar air-liquid interface to stabilise the lungs against physical forces operating along the compression-expansion breathing cycles. At the same time, surfactant integrates elements establishing a primary barrier against the entry of pathogens. Lack or deficiencies of the surfactant system are associated with respiratory pathologies, which treatment often includes supplementation with exogenous materials. The present review summarises current models on the molecular mechanisms of surfactant function, with particular emphasis in its biophysical properties to stabilise the lungs and the molecular alterations connecting impaired surfactant with diseased organs. It also provides a perspective on the current surfactant-based strategies to treat respiratory pathologies. This article is part of a Special Issue entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy. Copyright © 2014 Elsevier B.V. All rights reserved.