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991.
Due to concerns about data quality, McKechnie, Coe, Gerson, and Wolf ( 2016 ) questioned the conclusions of our study (Khaliq et al., 2015 ) published in this journal. Here, we argue that most of the questioned data points are in fact useful for macrophysiological analyses, mostly because the vast majority of data are explicitly reported in the peer‐reviewed physiological literature. Furthermore, we show that our conclusions remain largely robust irrespective of the data inclusion criterion. While we think that constructive debates about the adequate use of primary data in meta‐studies as well as more transparency in data inclusion criteria are indeed useful, we also emphasize that data suitability should be evaluated in the light of the scope and scale of the study in which they are used. We hope that this discussion will not discourage the exchange between disciplines such as biogeography and physiology, as this integration is needed to address some of the most urgent scientific challenges.  相似文献   
992.
High‐power, durable composite fuel cell membranes are fabricated here by direct membrane deposition (DMD). Poly(vinylidene fluoride‐co ‐hexafluoropropylene) (PVDF‐HFP) nanofibers, decorated with CeO2 nanoparticles are directly electrospun onto gas diffusion electrodes. The nanofiber mesh is impregnated by inkjet‐printed Nafion ionomer dispersion. This results in 12 µm thin multicomponent composite membranes. The nanofibers provide membrane reinforcement, whereas the attached CeO2 nanoparticles promote improved chemical membrane durability due to their radical scavenging properties. In a 100 h accelerated stress test under hot and dry conditions, the reinforced DMD fuel cell shows a more than three times lower voltage decay rate (0.39 mV h?1) compared to a comparably thin Gore membrane (1.36 mV h?1). The maximum power density of the DMD fuel cell drops by 9%, compared to 54% measured for the reference. Impedance spectroscopy reveals that ionic and mass transport resistance of the DMD fuel cell are unaffected by the accelerated stress test. This is in contrast to the reference, where a 90% increase of the mass transport resistance is measured. Energy dispersive X‐ray spectroscopy reveals that no significant migration of cerium into the catalyst layers occurs during degradation. This proves that the PVDF‐HFP backbone provides strong anchoring of CeO2 in the membrane.  相似文献   
993.
Monitoring and control of pH is essential for the control of reaction conditions and reaction progress for any biocatalytic or biotechnological process. Microfluidic enzymatic reactors are increasingly proposed for process development, however typically lack instrumentation, such as pH monitoring. We present a microfluidic side‐entry reactor (μSER) and demonstrate for the first time real‐time pH monitoring of the progression of an enzymatic reaction in a microfluidic reactor as a first step towards achieving pH control. Two different types of optical pH sensors were integrated at several positions in the reactor channel which enabled pH monitoring between pH 3.5 and pH 8.5, thus a broader range than typically reported. The sensors withstood the thermal bonding temperatures typical of microfluidic device fabrication. Additionally, fluidic inputs along the reaction channel were implemented to adjust the pH of the reaction. Time‐course profiles of pH were recorded for a transketolase and a penicillin G acylase catalyzed reaction. Without pH adjustment, the former showed a pH increase of 1 pH unit and the latter a pH decrease of about 2.5 pH units. With pH adjustment, the pH drop of the penicillin G acylase catalyzed reaction was significantly attenuated, the reaction condition kept at a pH suitable for the operation of the enzyme, and the product yield increased. This contribution represents a further step towards fully instrumented and controlled microfluidic reactors for biocatalytic process development.  相似文献   
994.
Requirements for mitigation of the continued increase in greenhouse gas (GHG ) emissions are much needed for the North China Plain (NCP ). We conducted a meta‐analysis of 76 published studies of 24 sites in the NCP to examine the effects of natural conditions and farming practices on GHG emissions in that region. We found that N2O was the main component of the area‐scaled total GHG balance, and the CH 4 contribution was <5%. Precipitation, temperature, soil pH , and texture had no significant impacts on annual GHG emissions, because of limited variation of these factors in the NCP . The N2O emissions increased exponentially with mineral fertilizer N application rate, with =  0.2389e0.0058x for wheat season and =  0.365e0.0071x for maize season. Emission factors were estimated at 0.37% for wheat and 0.90% for maize at conventional fertilizer N application rates. The agronomic optimal N rates (241 and 185 kg N ha?1 for wheat and maize, respectively) exhibited great potential for reducing N2O emissions, by 0.39 (29%) and 1.71 (56%) kg N2O‐N ha?1 season?1 for the wheat and maize seasons, respectively. Mixed application of organic manure with reduced mineral fertilizer N could reduce annual N2O emissions by 16% relative to mineral N application alone while maintaining a high crop yield. Compared with conventional tillage, no‐tillage significantly reduced N2O emissions by ~30% in the wheat season, whereas it increased those emissions by ~10% in the maize season. This may have resulted from the lower soil temperature in winter and increased soil moisture in summer under no‐tillage practice. Straw incorporation significantly increased annual N2O emissions, by 26% relative to straw removal. Our analysis indicates that these farming practices could be further tested to mitigate GHG emission and maintain high crop yields in the NCP .  相似文献   
995.
Goal, Scope and Background In contrast to inventory data of energy and transport processes, public inventory data of chemicals are rather scarce. Chemicals are important to consider in LCA, because they are used in the production of many, if not all, products. Moreover, they may cause considerable environmental impacts. For these reasons, it was one goal of the new ecoinvent database to provide LCI data on chemicals. In this paper, the methods and procedures used for establishing LCIs of chemicals in ecoinvent are presented.Methods Three different approaches are suggested for situations of differing data availability. First, in the case of good data availability, the general quality guidelines of ecoinvent can be followed. Second, a procedure is proposed for the translation of aggregated inventory data (cumulative LCI results) from industry into the ecoinvent format. This approach was used, if adequate unit process data was not available. Third, a procedure is put forward for estimating inventory data using stoichiometric equations from technical literature as a main information source. This latter method was used if no other information was available. The application of each of the three procedures is illustrated with the help of a case study.Results and Conclusion When sufficient information is available to follow the general guidelines of ecoinvent, the resulting dataset is characterized by a high degree of detail, and it is thus of high quality. For chemicals, however, the application of the standard procedure is possible in only a few cases. When using industrial data, the main drawback is the fact that those data are often available only as aggregated data, thus being out of tune with the quality guidelines of ecoinvent and its main aim, the harmonization of LCI data. As a third approach, the use of the stoichiometric reaction equation is used for the compilation of LCI datasets of chemicals. This approach represents an alternative to neglecting chemicals completely, but it contains a high risk to not consider important aspects of the life cycle of the respective substance.Outlook Further work in the area of chemicals should focus on an improvement of datasets, so far established by either of the two estimation procedures (APME method; estimation based on technical literature) described. Besides the improvement of already established inventories, the compilation of further harmonized inventories of specific types of chemicals (e.g. solvents) or of chemicals for new industrial sectors (e.g. electronics industry) are in discussion.  相似文献   
996.
Enrichment cultures for free-swimming microaerophilic bacteria were prepared from marine sulfidic sediment samples (Nivå Bay, Denmark). We observed nine different morphotypes; three of these morphotypes represented already-described species, i.e., Thiovulum majus, “Candidatus Ovobacter propellens,” and an as-yet-unnamed large vibrioid bacterium. In addition, we observed several morphotypes of spirilla and one vibrioid morphotype. A common feature of all investigated bacteria was that they aggregated chemotactically at the oxic-anoxic interface, whereas preferred oxygen concentration were in the range of 1 to 10 μM. The motile behavior and flagellar dynamics are analyzed in detail with an emphasis on spirilla.  相似文献   
997.
Functional Analysis of Three Plasmids from Lactobacillus plantarum   总被引:1,自引:0,他引:1       下载免费PDF全文
Lactobacillus plantarum WCFS1 harbors three plasmids, pWCFS101, pWCFS102, and pWCFS103, with sizes of 1,917, 2,365, and 36,069 bp, respectively. The two smaller plasmids are of unknown function and contain replication genes that are likely to function via the rolling-circle replication mechanism. The host range of the pWCFS101 replicon includes Lactobacillus species and Lactococcus lactis, while that of the pWCFS102 replicon also includes Carnobacterium maltaromaticum and Bacillus subtilis. The larger plasmid is predicted to replicate via the theta-type mechanism. The host range of its replicon seems restricted to L. plantarum. Cloning vectors were constructed based on the replicons of all three plasmids. Plasmid pWCFS103 was demonstrated to be a conjugative plasmid, as it could be transferred to L. plantarum NC8. It confers arsenate and arsenite resistance, which can be used as selective markers.  相似文献   
998.
Vancomycin-resistant enterococcci (VRE) in Europe are thought to have emerged partly due to the use of the glycopeptide avoparcin in animal husbandry. We compared the occurrence of VRE in geographical regions of Europe in which until 1997 large amounts of avoparcin were used (Spain, United Kingdom, and Denmark) with the occurrence of VRE in Sweden, where avoparcin was banned in 1986. We also studied the relatedness between VRE strains from different regions and habitats. In total, 2,580 samples were collected from humans, animals, and the environment (soil, sewage, recipient water). VRE resistant to 20 μg/ml vancomycin were identified in 8.2% of the samples and were found most frequently in raw and treated urban sewage samples (means, 71% and 36% of the samples, respectively), pig manure (17%), and hospital sewage (16%). The proportions of VRE-positive sewage samples were similar in Sweden, Spain, and the United Kingdom, whereas pig feces and manure were more often positive in Spain than in Sweden (30% versus 1%). Most VRE were Enterococcus faecium carrying vanA, and computerized biochemical phenotyping of the isolates of different ecological origins showed a high degree of polyclonality. In conclusion, it seems that animal-associated VRE probably reflect the former use of avoparcin in animal production, whereas VRE in human-associated samples may be a result of antibiotic use in hospitals. Since there seems to be a reservoir of the resistance genes in all countries studied, precautions must be taken to limit the use of antibiotics and antibiotic-like feed additives.  相似文献   
999.
1000.
The avian arginine vasotocin (AVT) synthesized in the hypothalamic magnocellular neurons and released from the posterior pituitary is known to be involved in the regulation of uterine contractions for oviposition in chickens. However, regulation of AVT synthesis and release within the magnocellular hypothalamus has not been elucidated. Galanin, the oviposition inducing factor in the oviduct of the hen, has been demonstrated to have sexually dimorphic stimulatory action in oxytocin- and vasopressin neurons in the mammalian hypothalamus. In this study, galanin and AVT immunoreactivity was investigated around the time of oviposition in the supraoptic nucleus (SON) to determine if galanin modulates AVT synthesis and/or release. Within SON neurons increased AVT immunoreactivity before oviposition and the decreased AVT immunoreactivity after oviposition implied function-related peptide release. The significantly increased number of galanin neurons co-localizing with AVT immediately after oviposition suggests that galanin is involved in the negative feedback to limit AVT release in the SON. Thus, these data support the idea that AVT in the SON is involved in central regulation of oviposition and that AVT release could be modulated by the neuropeptide galanin.  相似文献   
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