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61.
62.
Environ analysis, an input-output analysis for models of ecological systems, has been previously formulated for linear systems.
This note has a twofold purpose: first, we indicate that a variation of parameters technique can be applied, at least in principle,
to computeboth input and output environs; and second, we show that this technique may be used for computation of environs in nonautonomous,
nonlinear compartment models. This nonlinear theory, obtained as a direct extension of dynamical system developments, allows
the traditional environ partitioning of compartmental storages and flows. An example of a nonlinear nutrient-producer-consumer
system whose output environs can be computed asymptotically is presented to illustrate these concepts.
This research was supported by the U.S. Environmental Protection Agency under cooperative agreement R806727030. 相似文献
63.
Dietrich Behne Antonios Kyriakopoeulos Christian Weiss-Nowak Margrit Kalckloesch Christian Westphal Hildegard Gessner 《Biological trace element research》1996,55(1-2):99-110
The Se-containing proteins in 27 tissues of the rat were investigated by in vivo labeling with75Se-selenite, separation of the tissue homogenate proteins by SDS-polyacrylamide gel electrophoresis, and determination of
the labeled proteins by autoradiography. By using Se-depleted rats and a75Se-tracer with a high specific activity, Se compounds present at only very low concentrations could be detected. Besides the
13 Se-containing proteins previously described, for which apparent molecular masses of 12, 15, 18, 20, 22, 25, 28, 34, 56,
60, 65, 70, and 75 kD have been found here, a further 1575Se-labeled bands, with apparent molecular masses of 8, 10, 15.5, 16.5, 24, 32, 34.5, 38, 40, 41, 44, 45, 46.5, 53 and 116
kD could be distinguished. Two-dimensional separation of the kidney homogenate proteins showed that some of the Se-containing
bands could be resolved into several labeled spots. Most of the newly found compounds were present in various tissues, but
with some the enrichment in certain tissues suggested specific sites of action. 相似文献
64.
Aristidis S. Veskoukis Antonios Kyparos Vassilis Paschalis Michalis G. Nikolaidis 《Biomarkers》2016,21(3):208-217
The assessment of redox status is most frequently performed by measuring redox biomarkers. The spectrophotometer is the most commonly used analytical instrument in biochemistry. There is a huge number of spectrophotometric redox biomarkers and assays, thus distinguishing the most appropriate biomarkers and protocols is overwhelming. The aim of the present review is to propose valid and reliable spectrophotometric assays for measuring redox biomarkers in blood. It is hoped that this work will help researchers to select the most suitable redox biomarkers and assays. 相似文献
65.
66.
George Kakavelakis Ioannis Vangelidis Amelie Heuer‐Jungemann Antonios G. Kanaras Elefterios Lidorikis Emmanuel Stratakis Emmanuel Kymakis 《Liver Transplantation》2016,6(2)
A universal strategy for efficient light trapping through the incorporation of gold nanorods on the electron transport layer (rear) of organic photovoltaic devices is demonstrated. Utilizing the photons that are transmitted through the active layer of a bulk heterojunction photovoltaic device and would otherwise be lost, a significant enhancement in power conversion efficiency (PCE) of poly[N‐9′‐heptadecanyl‐2,7‐carbazole‐alt‐5,5‐(4′,7′‐di‐2‐thienyl‐2′,1′,3′‐benzothiadiazole)]:phenyl‐C71‐butyric acid methyl ester (PCDTBT:PC71BM) and poly[[4,8‐bis[(2‐ethylhexyl)oxy]benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl][3‐fluoro‐2‐[(2‐ethylhexyl)carbonyl]thieno[3,4‐b] thiophenediyl]] (PTB7):PC71BM by ≈13% and ≈8%, respectively. PCEs over 8% are reported for devices based on the PTB7:PC71BM blend. A comprehensive optical and electrical characterization of our devices to clarify the influence of gold nanorods on exciton generation, dissociation, charge recombination, and transport inside the thin film devices is performed. By correlating the experimental data with detailed numerical simulations, the near‐field and far‐field scattering effects are separated of gold nanorods (Au NRs), and confidently attribute part of the performance enhancement to the enhanced absorption caused by backscattering. While, a secondary contribution from the Au NRs that partially protrude inside the active layer and exhibit strong near‐fields due to localized surface plasmon resonance effects is also observed but is minor in magnitude. Furthermore, another important contribution to the enhanced performance is electrical in nature and comes from the increased charge collection probability. 相似文献
67.
PolyHIPEs show great promise as tissue engineering scaffolds due to the tremendous control of pore size and interconnectivity afforded by this technique. Highly porous, fully biodegradable scaffolds were prepared by polymerization of the continuous phase of high internal phase emulsions (HIPEs) containing the macromer poly(propylene fumarate) (PPF) and the cross-linker propylene fumarate diacrylate (PFDA). Toluene was used as a diluent to reduce the viscosity of the organic phase to enable HIPE formation. A range of polyHIPE scaffolds of different pore sizes and morphologies were generated by varying the diluent concentration (40-60 wt %), cross-linker concentration (25-75 wt %), and macromer molecular weight ( M n = 800-1000 g/mol). Although some formulations resulted in macroporous monoliths (pore diameter >500 microm), the majority of the polyHIPEs studied were rigid, microporous monoliths with average pore diameters in the range 10-300 microm. Gravimetric analysis confirmed the porosity of the microporous monoliths as 80-89% with most scaffolds above 84%. These studies demonstrate that emulsion templating can be used to generate rigid, biodegradable scaffolds with highly interconnected pores suitable for tissue engineering scaffolds. 相似文献
68.
Savalli N Pantazis A Yusifov T Sigg D Olcese R 《The Journal of biological chemistry》2012,287(26):21741-21750
Large conductance voltage- and Ca(2+)-activated K(+) (BK) channels are potent regulators of cellular processes including neuronal firing, synaptic transmission, cochlear hair cell tuning, insulin release, and smooth muscle tone. Their unique activation pathway relies on structurally distinct regulatory domains including one transmembrane voltage-sensing domain (VSD) and two intracellular high affinity Ca(2+)-sensing sites per subunit (located in the RCK1 and RCK2 domains). Four pairs of RCK1 and RCK2 domains form a Ca(2+)-sensing apparatus known as the "gating ring." The allosteric interplay between voltage- and Ca(2+)-sensing apparati is a fundamental mechanism of BK channel function. Using voltage-clamp fluorometry and UV photolysis of intracellular caged Ca(2+), we optically resolved VSD activation prompted by Ca(2+) binding to the gating ring. The sudden increase of intracellular Ca(2+) concentration ([Ca(2+)](i)) induced a hyperpolarizing shift in the voltage dependence of both channel opening and VSD activation, reported by a fluorophore labeling position 202, located in the upper side of the S4 transmembrane segment. The neutralization of the Ca(2+) sensor located in the RCK2 domain abolished the effect of [Ca(2+)](i) increase on the VSD rearrangements. On the other hand, the mutation of RCK1 residues involved in Ca(2+) sensing did not prevent the effect of Ca(2+) release on the VSD, revealing a functionally distinct interaction between RCK1 and RCK2 and the VSD. A statistical-mechanical model quantifies the complex thermodynamics interplay between Ca(2+) association in two distinct sites, voltage sensor activation, and BK channel opening. 相似文献
69.
Vezakis A Dellaportas D Polymeneas G Tasoulis MK Chondrogiannis C Melemeni A Polydorou A Fragulidis GP 《The Korean journal of parasitology》2012,50(2):147-150
Cystic disease of the spleen is an uncommon entity in general population. Most cases result from parasitic infection by Echinococcus granulosus, a form called splenic hydatid disease (SHD), with a reported frequency of 0.5-6.0% within abdominal hydatidosis. On the contrary, an isolated splenic involvement of hydatid disease is very uncommon even in endemic regions. Two cases of primary SHD managed with open and laparoscopic radical surgery in our department are reported herein. Primary SHD is a rare entity with non-specific symptoms underlying clinical suspicion by the physician for prompt diagnosis. Surgical treatment is the mainstay therapy, while laparoscopic approach when feasible is safe, offering the advantages of laparoscopic surgery. 相似文献
70.
Arsos G Kyparos A Moralidis E Kyparos D Georga S Sotiriadou S Matziari C Karakatsanis C 《Physiological research / Academia Scientiarum Bohemoslovaca》2009,58(1):21-28
The lipophilic cationic radiotracer (99m)Tc-sestamibi, known to be concentrated within mitochondria, is widely used for myocardial perfusion and to a lesser extent for muscle metabolism imaging. However, the exact distribution pattern in skeletal muscle has not been yet studied in detail. The present study aims to investigate the (99m)Tc-sestamibi uptake in rat skeletal muscle and myocardium in relation to their metabolic characteristics. (99m)Tc-sestamibi was i.v. administered in twenty adult male Wistar rats and uptake, as percent of injected dose per tissue gram (%ID/g), in the myocardium, soleus, extensor digitorum longus and gastrocnemius muscles was assessed 2 h after the injection. Muscle uptake was also correlated with myocardial uptake, muscle weight and body weight. Skeletal muscle (99m)Tc-sestamibi uptake was a small (9-16 %) fraction of that found in myocardium (1.71+/-0.63 %ID/g). Among the three hindlimb muscles considered, the slow-oxidative soleus muscle showed the highest uptake (0.28+/-0.16 %ID/g). Metabolically diverse parts of the gastrocnemius muscle showed different uptake. Skeletal muscle uptake was positively correlated with myocardial uptake and both were negatively correlated with tissue and body weight. Skeletal muscle and myocardium (99m)Tc-sestamibi uptake is related to their metabolic profile. Myocardium, with an exceptional rich mitochondrial concentration, shows much higher (99m)Tc-sestamibi uptake compared to skeletal muscles. Among muscles, uptake is dependent on their mitochondrial content. Evidence of matching exists between myocardial and muscle uptake, and both are size-dependent. 相似文献