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991.
Netherlands Heart Journal - Transvenous temporary cardiac pacing therapy (TV-TP) is widely used to treat life-threatening arrhythmias. Yet aggregated evidence on TV-TP is limited. We conducted...  相似文献   
992.
Netherlands Heart Journal - Previous studies have shown that hypertrophic cardiomyopathy mutation carriers have a decreased myocardial energy efficiency, which is thought to play...  相似文献   
993.
Phytochemistry Reviews - Cynara cardunculus health benefits have aroused much interest, leading to the discovery of valuable bioactive compounds with a crucial role in plant defence. Guaianolides...  相似文献   
994.
Phytochemistry Reviews - Cytokinins are plant hormones and play essential roles in regulating plant growth and development. They also have diverse pharmacological effects in animals and humans....  相似文献   
995.
996.
The açaí fruit depulping produces large amounts of long lignocellulosic fiber bundles that are disposed in the environment. Chemical pretreatments may improve açaí fibers favoring their usage in advanced materials. This work aimed to define optimal alkali reaction parameters to improve the properties of açaí fibers. Two NaOH concentrations (5 % and 10 %) and two reaction temperatures (80 °C and 100 °C) were tested. The raw and treated fibers were analyzed by scanning electron microscopy, Fourier transformed infrared spectroscopy, X‐ray diffraction, and thermal analyses. All the alkali pretreatments separated fibers from the bundles, unblocked pit channels by removing silicon structures, exposed the inner lignin, partially removed non‐cellulosic compounds, and raised the cellulose crystalline index. The highest temperature and NaOH content resulted in better cleaning and isolation of the fibers, while milder conditions better preserved the cellulose crystalline structure and thermal stability.  相似文献   
997.
Bioprocess and Biosystems Engineering - In this work, a fed-batch approach was adopted to overcome propionic acid lipase inactivation effects in the benzyl propionate direct esterification mediated...  相似文献   
998.
Sunburn is a physiological disorder that can be observed in fruits of several crops growing in areas with warm climates, as a result of photodamage due to an excess of heat and/or light irradiance (visible and ultraviolet light). The main cause is thought to be an increase in reactive oxygen species production which causes oxidative damage due to the incapacity of the fruit to recover from stress. This can result in a characteristic morphological and structural phenotype unacceptable to consumers, leading to severe losses in productivity for farmers. Fruits have a great array of mechanisms to mitigate or reduce reactive oxygen species production and the inactivation of photosynthetic apparatus, such as enhanced xanthophyll cycle-dependent energy dissipation, accumulation of photoprotective pigments and heat-shock proteins, and the biosynthesis of antioxidants, among others. Nevertheless, these mechanisms become inefficient when the stress factors altering the fruit surface exceed a certain threshold (of both duration and intensity). Although this disorder has been studied in detail and previous efforts have provided significant advances in understanding the underlying mechanisms causing sunburn in a number of fruits, further research is still needed. This will undoubtedly provide new approaches and tools for improving current mitigation strategies.  相似文献   
999.
Plants exposed to hostile environmental conditions such as drought or extreme temperatures usually undergo oxidative stress, which has long been assumed to significantly contribute to the damage suffered by the organism. Reactive oxygen species (ROS) overproduced under stress conditions were proposed to destroy membrane lipids and to inactivate proteins and photosystems, ultimately leading to cell death. Accordingly, considerable effort has been devoted, over the years, to improve stress tolerance by strengthening antioxidant and dissipative mechanisms. Although the notion that ROS cause indiscriminate damage in vivo has been progressively replaced by the alternate concept that they act as signaling molecules directing critical plant developmental and environmental responses including cell death, the induction of genes encoding antioxidant activities is commonplace under many environmental stresses, suggesting that their manipulation still offers promise. The features and consequences of ROS effects depend on the balance between various interacting pathways including ROS synthesis and scavenging, energy dissipation, conjugative reactions, and eventually reductive repair. They represent many possibilities for genetic manipulation. We report, herein, a comprehensive survey of transgenic plants in which components of the ROS-associated pathways were overexpressed, and of the stress phenotypes displayed by the corresponding transformants. Genetic engineering of different stages of ROS metabolism such as synthesis, scavenging, and reductive repair revealed a strong correlation between down-regulation of ROS levels and increased stress tolerance in plants grown under controlled conditions. Field assays are scarce, and are eagerly required to assess the possible application of this strategy to agriculture.  相似文献   
1000.
acta ethologica - Chemical pollution of aquatic environments has been increasing in recent times, causing great damage to the ecosystems and to the fishery sector. Pollutants can negatively alter...  相似文献   
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