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1.

Background, aim, and scope  

In order to assess the environmental sustainability of a novel wastewater treatment process based on power an electrochemical reactor by photovoltaic solar modules (photovoltaic solar electrochemical oxidation), a life cycle approach was considered to quantify the CO2 equivalent (CO2-eq.) emissions coming from the two supplying power systems to the electrochemical process: conventional grid power or photovoltaic solar power under Spain frame conditions.  相似文献   

2.
Dissimilatory metal reducing bacteria can exchange electrons extracellularly and hold great promise for their use in simultaneous wastewater treatment and electricity production. This study investigated the role of riboflavin, an electron carrier, in the decolourisation of Congo red in microbial fuel cells (MFCs) using Shewanella oneidensis MR-1 as a model organism. The contribution of the membrane-bound protein MtrC to the decolourisation process was also investigated. Within the range of riboflavin concentrations tested, 20 µM was found to be the best with >95% of the dye (initial concentration 200 mg/L) decolourised in MFCs within 50 h compared to 90% in the case where no riboflavin was added. The corresponding maximum power density was 45 mW/m2. There was no significant difference in the overall decolourisation efficiencies of Shewanela oneidensis MR-1 ΔMtrC mutants compared to the wild type. However, in terms of power production the mutant produced more power (Pmax 76 mW/m2) compared to the wild type (Pmax 46 mW/m2) which was attributed to higher levels of riboflavin secreted in solution. Decolourisation efficiencies in non-MFC systems (anaerobic bottles) were similar to those under MFC systems indicating that electricity generation in MFCs does not impair dye decolourisation efficiencies. The results suggest that riboflavin enhances both decolourisation of dyes and simultaneous electricity production in MFCs.  相似文献   

3.
Lithium‐ion capacitors (LICs) with capacitor‐type cathodes and battery‐type anodes are considered a promising next‐generation advanced energy storages system that meet the requirements of high energy density and power density. However, the mismatch of charge‐storage capacity and electrode kinetics between positive and negative electrodes remains a challenge. Herein, layered SnS2/reduced graphene oxide (RGO) nanocomposites are developed for negative electrodes and a 2D B/N codoped carbon (BCN) nanosheet is designed for the positive electrode. The SnS2/RGO derived from SnS2‐bonded RGO of high conductivity exhibits a capacity of 1198 mA h g?1 at 100 mA g?1. Boron and nitrogen atoms in BCN are found to promote adsorption of anions, which enhance the pseudocapacitive contribution as well as expanding the voltage of LICs. A quantitative kinetics analysis indicates that the SnS2/RGO electrodes with a dominating capacitive mechanism and a diminished intercalation process, benefit the kinetic balance between the two electrodes. With this particular structure, the LIC is able to operate at the highest operating voltage for these devices recorded to date (4.5 V), exhibiting an energy density of 149.5 W h kg?1, a power density of 35 kW kg?1, and a capacity retention ratio of 90% after 10 000 cycles.  相似文献   

4.
Manuel Serrano 《The EMBO journal》2015,34(11):1439-1441
Cellular senescence is a response to stress that disables cell proliferation and orchestrates an inflammatory process that eliminates damaged cells. The first pro‐senescence drugs for cancer treatment are now a clinical reality, but still few targets have been identified whose inactivation results in cancer cell senescence. Current work published in this issue of The EMBO Journal makes an important contribution to this area by discovering that pharmacological inhibition of the tyrosine phosphatase SHP2 blocks mouse mammary cancer through the induction of senescence (Lan et al, 2015 ).  相似文献   

5.
Generally there is a correlation between the amount of zeaxanthin accumulated within the chloroplast of oxygenic photosynthetic organisms and the degree of non-photochemical quenching (NPQ). Although constitutive accumulation of zeaxanthin can help protect plants from photo-oxidative stress, organisms with such a phenotype have been reported to have altered rates of NPQ induction. In this study, basic fluorescence principles and the routinely used NPQ analysis technique were employed to investigate excitation energy quenching in the unicellular green alga Dunaliella salina, in both wild type (WT) and a mutant, zea1, constitutively accumulating zeaxanthin under all growth conditions. The results showed that, in D. salina, NPQ is a multi-component process consisting of energy- or ΔpH-dependent quenching (qE), state-transition quenching (qT), and photoinhibition quenching (qI). Despite the vast difference in the amount of zeaxanthin in WT and the zea1 mutant grown under low light, the overall kinetics of NPQ induction were almost the same. Only a slight difference in the relative contribution of each quenching component could be detected. Of all the NPQ subcomponents, qE seemed to be the primary NPQ operating in this alga in response to short-term exposure to excessive irradiance. Whenever qE could not operate, i.e., in the presence of nigericin, or under conditions where the level of photon flux is beyond its quenching power, qT and/or qI could adequately compensate its photoprotective function.  相似文献   

6.
In many animal species, male acoustic courtship signals are evaluated by females for mate choice. At the behavioural level, this phenomenon has been well studied. However, although several song characteristics have been determined to affect the attractiveness of a given song, the mechanisms of the evaluation process remain largely unclear. Here, we present a simple neural network model for analysing and evaluating courtship songs of Chorthippus biguttulus males in real-time. The model achieves a high predictive power of the attractiveness of artificial songs as assigned by real Chorthippus biguttulus females: about 87% of the variance can be explained. It also allows us to determine the relative contribution of different song characteristics to overall attractiveness and how each of the song components influences female responsiveness. In general, the obtained results closely match those of empirical studies. Therefore, our model may be used to obtain a first estimate of male song attractiveness and may thus complement actual testing of female responsiveness in the laboratory. In addition, the model allows including and testing novel song parameters to generate new hypotheses for further experimental studies. The supplemental material of this article contains the article’s data in an active, re-usable format.  相似文献   

7.
Parsing a mental operation into components, characterizing the parallel or serial nature of this flow, and understanding what each process ultimately contributes to response time are fundamental questions in cognitive neuroscience. Here we show how a simple theoretical model leads to an extended set of predictions concerning the distribution of response time and its alteration by simultaneous performance of another task. The model provides a synthesis of psychological refractory period and random-walk models of response time. It merely assumes that a task consists of three consecutive stages—perception, decision based on noisy integration of evidence, and response—and that the perceptual and motor stages can operate simultaneously with stages of another task, while the central decision process constitutes a bottleneck. We designed a number-comparison task that provided a thorough test of the model by allowing independent variations in number notation, numerical distance, response complexity, and temporal asynchrony relative to an interfering probe task of tone discrimination. The results revealed a parsing of the comparison task in which each variable affects only one stage. Numerical distance affects the integration process, which is the only step that cannot proceed in parallel and has a major contribution to response time variability. The other stages, mapping the numeral to an internal quantity and executing the motor response, can be carried out in parallel with another task. Changing the duration of these processes has no significant effect on the variance.  相似文献   

8.
Parsing a Cognitive Task: A Characterization of the Mind's Bottleneck   总被引:1,自引:1,他引:0  
Parsing a mental operation into components, characterizing the parallel or serial nature of this flow, and understanding what each process ultimately contributes to response time are fundamental questions in cognitive neuroscience. Here we show how a simple theoretical model leads to an extended set of predictions concerning the distribution of response time and its alteration by simultaneous performance of another task. The model provides a synthesis of psychological refractory period and random-walk models of response time. It merely assumes that a task consists of three consecutive stages—perception, decision based on noisy integration of evidence, and response—and that the perceptual and motor stages can operate simultaneously with stages of another task, while the central decision process constitutes a bottleneck. We designed a number-comparison task that provided a thorough test of the model by allowing independent variations in number notation, numerical distance, response complexity, and temporal asynchrony relative to an interfering probe task of tone discrimination. The results revealed a parsing of the comparison task in which each variable affects only one stage. Numerical distance affects the integration process, which is the only step that cannot proceed in parallel and has a major contribution to response time variability. The other stages, mapping the numeral to an internal quantity and executing the motor response, can be carried out in parallel with another task. Changing the duration of these processes has no significant effect on the variance.  相似文献   

9.
Dilution of protein–surfactant complexes is an integrated step in microfluidic protein sizing, where the contribution of free micelles to the overall fluorescence is reduced by dilution. This process can be further improved by establishing an optimum surfactant concentration and quantifying the amount of protein based on the fluorescence intensity. To this end, we study the interaction of proteins with anionic sodium dodecyl sulfate (SDS) and cationic hexadecyl trimethyl ammonium bromide (CTAB) using a hydrophobic fluorescent dye (sypro orange). We analyze these interactions fluourometrically with bovine serum albumin, carbonic anhydrase, and beta‐galactosidase as model proteins. The fluorescent signature of protein–surfactant complexes at various dilution points shows three distinct regions, surfactant dominant, breakdown, and protein dominant region. Based on the dilution behavior of protein–surfactant complexes, we propose a fluorescence model to explain the contribution of free and bound micelles to the overall fluorescence. Our results show that protein peak is observed at 3 mM SDS as the optimum dilution concentration. Furthermore, we study the effect of protein concentration on fluorescence intensity. In a single protein model with a constant dye quantum yield, the peak height increases with protein concentration. Finally, addition of CTAB to the protein–SDS complex at mole fractions above 0.1 shifts the protein peak from 3 mM to 4 mM SDS. The knowledge of protein–surfactant interactions obtained from these studies provides significant insights for novel detection and quantification techniques in microfluidics.  相似文献   

10.
Although microalgae are considered as a promising feedstock for biofuels, the energy efficiency of the production process needs to be significantly improved. Due to their small size and low concentration in the culture medium, cost‐efficient harvesting of microalgae is a major challenge. In this study, the use of electro‐coagulation–flocculation (ECF) as a method for harvesting a freshwater (Chlorella vulgaris) and a marine (Phaeodactylum tricornutum) microalgal species is evaluated. ECF was shown to be more efficient using an aluminum anode than using an iron anode. Furthermore, it could be concluded that the efficiency of the ECF process can be substantially improved by reducing the initial pH and by increasing the turbulence in the microalgal suspension. Although higher current densities resulted in a more rapid flocculation of the microalgal suspension, power consumption, expressed per kg of microalgae harvested, and release of aluminum were lower when a lower current density was used. The aluminum content of the harvested microalgal biomass was less than 1% while the aluminum concentration in the process water was below 2 mg L−1. Under optimal conditions, power consumption of the ECF process was around 2 kWh kg−1 of microalgal biomass harvested for Chlorella vulgaris and ca. 0.3 kWh kg−1 for Phaeodactylum tricornutum. Compared to centrifugation, ECF is thus more energy efficient. Because of the lower power consumption of ECF in seawater, ECF is a particularly attractive method for harvesting marine microalgae. Biotechnol. Bioeng. 2011;108: 2320–2329. © 2011 Wiley Periodicals, Inc.  相似文献   

11.
Longitudinal bone growth is a tightly regulated process that relies on complex synchronized mechanisms at the growth plate. Chronic paediatric inflammatory diseases are well accepted to lead to growth retardation and this is likely due to raised inflammatory cytokine levels and reduced growth hormone (GH)/insulin‐like growth factor‐1 (IGF‐I) signalling. The precise cellular mechanisms responsible for this inhibition are unclear and therefore in this article, we will review the potential interactions between inflammatory cytokines and the GH/IGF‐I axis in the regulation of bone growth. In particular, we will emphasis the potential contribution of the suppressors of cytokine signalling (SOCS) proteins, and in particular SOCS2, in mediating this process. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

12.
The industrial use of starter cultures containing a consortium of different strains from the same species is nowadays seen as a possible strategy to enhance the organoleptic complexity of wines. To assess the relative contribution of each strain to the final product it is essential to quantify population evolution during the wine fermentation process, which requires strain-specific methods to identify and differentiate each strain. In the present study, a molecular method based on analysis of the polymorphisms exhibited by the PCR-amplification of the delta regions of three Saccharomyces cerevisiae strains was developed. A set of three pairs of primers (delta1–delta2, delta12–delta2, delta12–delta21) was used for each strain, and analysis of the resulting polymorphism patterns showed that the delta12–delta2 primer pair exhibited the highest resolution and discriminatory power. Thus, this pair of primers was selected to monitor the population evolution of a laboratory-scale wine fermentation performed in synthetic grape juice that was inoculated with similar amounts of each strain. The results showed that all strains grew together during the exponential growth phase (2–3 days) and maintained high cell density values (106–107 cfu ml−1) throughout the stationary growth phase without significantly changing their relative population proportion, thus indicating that each strain can influence the chemical composition and final flavor of wine, albeit at different levels. This study also showed that PCR-amplification of DNA delta sequences of S. cerevisiae strains is a reproducible, strain-specific and simple method that can be used successfully to monitor yeast strain population dynamics during wine fermentations.  相似文献   

13.
The growth and aroma contribution of Microbacterium foliorum, Proteus vulgaris and Psychrobacter sp., some common but rarely mentioned cheese bacteria, were investigated in a cheese model deacidified by Debaryomyces hansenii during the ripening process. Our results show that these bacteria had distinct growth and cheese flavour production patterns during the ripening process. P. vulgaris had the greatest capacity to produce not only the widest variety but also the highest quantities of volatile compounds with low olfactive thresholds, e.g. volatile sulphur compounds and branched-chain alcohols. Such compounds produced by P. vulgaris increased after 21 days of ripening and reached a maximum at 41 days. The three bacteria studied exhibited various degrees of caseinolytic, aminopeptidase and deaminase activities. Moreover, P. vulgaris had a greater capacity for hydrolysing casein and higher deaminase activity. Our results show that P. vulgaris, a Gram-negative bacterium naturally present on the surface of ripened cheeses, could produce high concentrations of flavour compounds from amino acid degradation during the ripening process. Its flavouring role in cheese cannot be neglected. Moreover, it could be a useful organism for producing natural flavours as dairy ingredients.  相似文献   

14.
Mixed stock analysis (MSA) estimates the relative contributions of distinct populations in a mixture of organisms. Increasingly, MSA is used to judge the presence or absence of specific populations in specific mixture samples. This is commonly done by inspecting the bootstrap confidence interval of the contribution of interest. This method has a number of statistical deficiencies, including almost zero power to detect small contributions even if the population has perfect identifiability. We introduce a more powerful method based on the likelihood ratio test and compare both methods in a simulation demonstration using a 17 population baseline of sockeye salmon, Oncorhynchus nerka, from the Kenai River, Alaska, watershed. Power to detect a nonzero contribution will vary with the population(s) identifiability relative to the rest of the baseline, the contribution size, mixture sample size, and analysis method. The demonstration shows that the likelihood ratio method is always more powerful than the bootstrap method, the two methods only being equal when both display 100% power. Power declines for both methods as contribution declines, but it declines faster and goes to zero for the bootstrap method. Power declines quickly for both methods as population identifiability declines, though the likelihood ratio test is able to capitalize on the presence of 'perfect identification' characteristics, such as private alleles. Given the baseline-specific nature of detection power, researchers are encouraged to conduct a priori power analyses similar to the current demonstration when planning their applications.  相似文献   

15.
顾佰和  谭显春  穆泽坤  曾元 《生态学报》2015,35(19):6405-6413
电力行业低碳转型是中国低碳经济转型进程中关键行业之一,如何科学分析电力行业的碳减排潜力,确定操作性强的低碳转型路线、提出有效的政策措施是中国政府亟待解决的焦点问题之一。考虑终端电力消费、低碳能源发电占比、火力发电结构、火力发电效率、线损率等因素,构建了自底向上的电力行业CO2排放核算模型,在此基础上,利用情景分析方法探索中国电力行业2015和2020年的CO2减排潜力,进一步利用对数平均权重分解法(LMDI,Logarithmic Mean weight Divisia Index method)对电力行业CO2减排影响因素的贡献度做了归因分析。结果显示,相比基准情景,在当前政策情景和低碳政策情景下,电力行业将分别带来27.0亿t和36.9亿t的CO2减排量。低碳能源发电和火力发电效率是未来对CO2减排最重要的两个贡献因素。终端电力消费量一直是促进电力行业CO2排放增长最重要的贡献因素,因此通过电力需求侧管理等手段控制电力消费量对电力行业的低碳发展至关重要。最后结合减排贡献因素分析的结果为中国电力行业低碳发展提出了相应的政策建议。  相似文献   

16.
Multicellular organisms are composed of many cell types that acquire their specific fate through a precisely controlled pattern of gene expression in time and space dictated in part by cell type‐specific promoter activity. Understanding the contribution of highly specialized cell types in the development of a whole organism requires the ability to isolate or analyze different cell types separately. We have characterized and validated a large collection of root cell type‐specific promoters and have generated cell type‐specific marker lines. These benchmarked promoters can be readily used to evaluate cell type‐specific complementation of mutant phenotypes, or to knockdown gene expression using targeted expression of artificial miRNA. We also generated vectors and characterized transgenic lines for cell type‐specific induction of gene expression and cell type‐specific isolation of nuclei for RNA and chromatin profiling. Vectors and seeds from transgenic Arabidopsis plants will be freely available, and will promote rapid progress in cell type‐specific functional genomics. We demonstrate the power of this promoter set for analysis of complex biological processes by investigating the contribution of root cell types in the IRT1‐dependent root iron uptake. Our findings revealed the complex spatial expression pattern of IRT1 in both root epidermis and phloem companion cells and the requirement for IRT1 to be expressed in both cell types for proper iron homeostasis.  相似文献   

17.
Brown adipose tissue (BAT) has long been thought to be absent or very scarce in human adults so that its contribution to energy expenditure was not considered as relevant. The recent discovery of thermogenic BAT in human adults opened the field for innovative strategies to combat overweight/obesity and associated diseases. This energy-dissipating function of BAT is responsible for adaptive thermogenesis in response to cold stimulation. In this context, adipocytes can be converted, within white adipose tissue (WAT), into multilocular adipocytes expressing UCP1, a mitochondrial protein that plays a key role in heat production by uncoupling the activity of the respiratory chain from ATP synthesis. These adipocytes have been named “brite” or “beige” adipocytes. Whereas BAT has been studied for a long time in murine models both in vivo and in vitro, there is now a strong demand for human cellular models to validate and/or identify critical factors involved in the induction of a thermogenic program within adipocytes. In this review we will discuss the different human cellular models described in the literature and what is known regarding the regulation of their differentiation and/or activation process. In addition, the role of microRNAs as novel regulators of brown/“brite” adipocyte differentiation and conversion will be depicted. Finally, investigation of both the conversion and the metabolism of white-to-brown converted adipocytes is required for the development of therapeutic strategies targeting overweight/obesity and associated diseases. This article is part of a Special Issue entitled Brown and White Fat: From Signaling to Disease.  相似文献   

18.
Aim To compare the evolutionary and ecological patterns of two extensively studied island biotas with differing geological histories (the Hawaiian Islands and the Greater Antilles). We evaluated the results from PACT (phylogenetic analysis for comparing trees), an innovative approach that has been proposed to reveal general patterns of biotic expansion (between regions) and in situ (within a region) diversification, as well as species–area relationships (SAR) and the taxon pulse dynamic. Location The Hawaiian Islands and Greater Antilles. Methods We used the PACT algorithm to construct general area cladograms and identified biotic expansion and in situ nodes. We analysed the power‐law SAR and relative contribution of biotic expansion and in situ diversification events using power‐law and linear regression analyses. Results Both biotic expansion and in situ nodes were prevalent throughout the PACT general area cladograms (Greater Antilles, 55.9% biotic expansion, 44.1% in situ; Hawaiian Islands, 40.6% biotic expansion, 59.4% in situ). Of the biotic expansion events, both forward and backward events occurred in both regions (Greater Antilles, 85.1% forward, 14.9% backward; Hawaiian Islands, 65% forward, 35% backward). Additionally, there is a power‐law SAR for the Greater Antilles but not for the Hawaiian Islands. However, exclusion of Hawai'i (the youngest, largest Hawaiian Island) produced a power‐law SAR for the Hawaiian Islands. Main conclusions The prevalence of in situ events as well as forward and backward biotic expansion events reveals that both Hawaiian and Greater Antillean biotas have evolved through alternating episodes of biotic expansion and in situ diversification. These patterns are characteristic of the taxon pulse dynamic, for which few data have previously been recorded on islands. Additionally, our analysis revealed that historical influences on the power‐law SARs are pronounced in both assemblages: old, small islands are relatively species rich and young, large islands are relatively species poor. Thus, our PACT results are consistent with hypotheses of geological influence on the evolution of island biotas and also provide greater insight into the role of the taxon pulse dynamic in the formation of island equilibria.  相似文献   

19.
20.
The proterochampsids are a Triassic group of superficially crocodile-like forms belonging to the Archosauriformes. In the present contribution, we present new information regarding the braincase of the proterochampsid Proterochampsa Reig 1959, from the Ischigualasto Formation (Carnian) of Argentina, and discuss its phylogenetic considerations. Some unique neurocranial features of Proterochampsa are described, including: the prominence and thickness of the V-shaped ridge that surrounds the basisphenoidal fossa; the medially concave lateral arms of the same ridge; and the semilunar depression on the parabasisphenoid ventrolaterally exposed. Other features are only shared with likely unrelated archosauriforms, including: the great lateral development of the basipterygoid processes and caudal development of its distal end; an eight-shaped metotic foramen; laterally directed basipterygoid processes; and rostral boundary of the basisphenoidal recess V-shaped. Proterochampsa differs in many other aspects from the archosauriform Chanaresuchus, including: a proportionally shorter basioccipital basal tubera; cultriform process ovoid in cross-section; longitudinal sulcus dorsal to the basipterygoid process; deep basisphenoidal recess; and the absence of a prominent intertuberal plate. In many braincase features, Proterochampsa is more similar to archosaurs than to Euparkeria, erythrosuchids and Proterosuchus. They include a reduced semilunar depression. A ventral border of the basioccipital forming a wide convexity and a dorsoventrally thin paroccipital process likely represents a feature shared with Chanaresuchus, but not with Doswellia and other basal archosauriforms.  相似文献   

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