202 research outputs found
Genetic Studies of Induced Mutants in \u3ci\u3eMelilotus alba\u3c/i\u3e. I. Short-Internode Dwarf, Curled Leaf, Multifoliolate Leaf, and Cotyledonary Branching
Information obtained from the F1, F2, and F3 generations of crosses between the normal annual M. alba progenitor line and the four mutants, short-internode dwarf, curled leaf, multifoliolate leaf, and cotyledonary branching, indicates that each character is conditioned by a single pair of alleles. The multifoliolate leaf character is dominant over the normal phenotype; the other three mutant characters are recessive. The symbols dw, cl, Mf, and cb are proposed as designations for the respective mutant genes
Blending chitosan-g-poly(caprolactone) with poly(caprolactone) by electrospinning to produce functional fiber mats for tissue engineering applications
Use of electrospun fiber mats for tissue engineering applications has become increasingly prominent. One of the most important polymers in research, poly(ε-caprolactone) (PCL), however, lacks biological performance, easy access to modifications and cellular recognition sites. To improve these properties and to enable further modifications, PCL was blended with chitosan grafted with PCL (CS-g-PCL) and subsequently processed via electrospinning. In this way, chitosan was enriched at the fiber's surface presenting cationic amino groups. The fiber mats were analyzed by various techniques such as scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and X-ray photoelectron spectroscopy (XPS). Furthermore, analyzing thermal properties and crystallinity, showed that an increased content of CS-g-PCL in blend composition leads to a higher overall crystallinity in produced fiber mats. Blending CS-g-PCL into PCL significantly increased initial cellular attachment and proliferation as well as cell vitality, while maintaining adequate mechanical properties, fiber diameter, and interstitial volume. As proof of principle for easy access to further modification, fluorescently labeled alginate (Alg-FA) was attached to the fiber's surface and verified by CLSM. Hence, blending CS-g-PCL with PCL can overcome an inherent weakness of PCL and create bioactive implants for tissue engineering applications. © 2019 The Authors. Journal of Applied Polymer Science published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 137, 48650. © 2019 The Authors. Journal of Applied Polymer Science published by Wiley Periodicals, Inc
The Role of Surface Characteristics in the Initial Adhesion of Human Bone-Derived Cells on Ceramics
The tissue/biomaterial interactions of three biomaterials of potential use in bone implants were studied in vitro. The mechanism of cell adherence to various ceramic substrata has been investigated by measurement of short term (90 minutes) cell attachment and spreading rate. We have determined the effect of two serum glycoproteins, fibronectin and vitronectin, on the adhesion of human bone derived cells (HBD-cells) cultured on three different types of ceramics {alumina (Al2O3), hydroxyapatite (HAP) and yttria-doped tetragonal zirconia polycrystal (Y-TZP)} . The attachment of HBD-cells to alumina and hydroxyapatite was approximately 60% of that to Y-TZP. Furthermore, the requirement for serum adhesive glycoproteins vitronectin and fibronectin, for HBD-cell attachment to Al2O3, HAP and Y-TZP reveals a dependence upon serum vitronectin for the initial attachment of HBD-cells. There was no difference in the mechanism of initial adhesion between bioactive hydroxyapatite, as compared to the bioinert ceramics, alumina and Y-TZP, so the mechanism of the initial attachment of HBD-cells appears not to be dependent on the ceramic composition. The effect of surface roughness of alumina in the order of 8.3-70.7 nm on the adhesion of HBD-cells was also investigated. The Al2O3 disks with a root mean square surface roughness (roughness assessment: Ra) value of 8.3 nm had significantly fewer cells attached than those with an Ra of 70.7 nm
A new class of porous silicon electrochemical transducers built from pyrolyzed polyfurfuryl alcohol
Carbon-based nanomaterials are key to developing high-performing electrochemical sensors with improved
sensitivity and selectivity. Nonetheless, limitations in their fabrication and integration into devices often
constrain their practical applications. Moreover, carbon nanomaterials-based electrochemical devices still face
problems such as large background currents, poor stability, and slow kinetics. To advance towards a new class of
carbon nanostructured electrochemical transducers, we propose the in-situ polymerization and carbonization of
furfuryl alcohol (FA) on porous silicon (pSi) to produce a tailored and highly stable transducer. The thin layer of
polyfurfuryl alcohol (PFA) that conformally coats the pSi scaffold transforms into nanoporous carbon when
subjected to pyrolysis above 600 â—¦C. The morphological and chemical properties of PFA-pSi were characterized
by scanning electron microscopy, and Raman and X-ray photoelectron spectroscopies. Their stability and electrochemical
performance were investigated by cyclic voltammetry and electrochemical impedance spectroscopy
in [Fe(CN)6]3-/4-, [Ru(NH3)6]2+/3+, and hydroquinone. PFA-pSi showed superior electrochemical performance
compared to screen-printed carbon electrodes while also surpassing glassy carbon electrodes in specific aspects.
Besides, PFA-pSi has the additional advantage of easy tuning of the electroactive surface area. To prove its
potential for biosensing purposes, a DNA sensor based on quantifying the partial pore blockage of the pSi upon
target hybridization was built on PFA-pSi. The sensor showed a limit of detection of 1.4 pM, outperforming other
sensors based on the same sensing mechanism
The long run relationship between private consumption and wealth : common and idiosyncratic effects
We investigate the long run relationship between private consump- tion, disposable income and wealth approximated by equity and house price indices for a panel of 15 industrialized countries. Consumption, income and wealth are cointegrated in their common components. The impact of house prices exceeds the effect arising from equity wealth. The long run vector is broadly in line with the life cycle permanent income hypothesis, if house prices are allowed to enter the relationship. At the idiosyncratic level, a long run equilibrium is detected between consumption and income, i.e. the wealth variable can be excluded. The income elasticity in the idiosyncratic relationship is significantly less than unity. Hence, the presence of wealth effects in consumption equations arises from the international integration of asset markets and points to the relevance of risk sharing activities of agents. Without sufficient opportunities, an increase in national saving rates would be expected, leading to a lower path of private consumption expenditures.info:eu-repo/semantics/publishedVersio
A Further Examination of the Export-Led Growth Hypothesis
This paper challenges the common view that exports generally contribute more to GDP growth than a pure change in export volume, as the export-led growth hypothesis predicts. Applying panel cointegration techniques to a production function with non-export GDP as the dependent variable, we find for a sample of 45 developing countries that: (i) exports have a positive short-run effect on non-export GDP and vice versa (short-run bidirectional causality), (ii) the long-run effect of exports on non-export output, however, is negative on average, but (iii) there are large differences in the longrun effect of exports on non-export GDP across countries. Cross-sectional regressions indicate that these cross-country differences in the long-run effect of exports on nonexport GDP are significantly negatively related to cross-country differences in primary export dependence and business and labor market regulation. In contrast, there is no significant association between the growth effect of exports and the capacity of a country to absorb new knowledge
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