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1.
Bioturbation by benthic infauna has important implications for the fate of contaminants as well as for changes to the sediment
structure, chemistry and transport characteristics. There is an extensive literature dealing with the influence of sedimentary
variables on the structure and function of infaunal marine and estuarine organisms but less is known of the converse, the
influence of biota on sedimentary structure. Although some work has been carried out regarding spatial and temporal patterns
of bioturbation, little attention has been given to the effects of pollution. The paper gives a framework of animal sediment
relationships in an intertidal environment and discusses the general role of macrofauna in structuring and modifying sedimentary
features. A brief outline of the various techniques used for quantifying the degree of bioturbation is given and some of these
techniques have then been used to demonstrate the effect of a petrochemical discharge on the bioturbation potential of intertidal
communities in the Humber estuary, eastern England. These studies indicate an increase in bioturbation with increasing distance
from the source of pollution, not only because of differences in abundance, animal size and depth of activity but also because
of the difference in species composition between the communities. As a means of interpreting the responses, the species present
have been broadly classified in terms of their feeding strategy and sediment modification potential. The paper concludes by
discussing the potential impact, in terms of effect on sediment transport, of selectively removing the different guilds (by
pollution).
Received: 8 February 1999 / Received in revised form: 10 May 1999 / Accepted: 14 May 1999 相似文献
2.
Tippawan Siritientong Walter Bonani Antonella Motta Claudio Migliaresi 《Bioscience, biotechnology, and biochemistry》2016,80(2):241-249
Sericin was extracted from three strains of Thai Bombyx mori silk cocoons (white shell Chul1/1, greenish shell Chul3/2, and yellow shell Chul4/2) by a high-pressure and high-temperature technique. The characteristics of sericin extracted from different fractions (15, 45, and 60 min extraction process) were compared. No differences in amino acid composition were observed among the three fractions. For all silk strains, sericin extracted from a 15-min process presented the highest molecular weight. The biological potential of the different sericin samples as a bioadditive for 3T3 fibroblast cells was assessed. When comparing sericin extracted from three silk strains, sericin fractions extracted from Chul4/2 improved cell proliferation, while sericin from Chul 1/1 activated Type I collagen production to the highest extent. This study allows the natural variability of sericin obtained from different sources and extraction conditions to be addressed and provides clues for the selection of sericin sources. 相似文献
3.
《Bioorganic & medicinal chemistry》2016,24(21):5431-5439
Heat shock protein 90 (Hsp90) as a molecular target for oncology therapeutics has attracted much attention in the last decade. The Hsp90 multichaperone complex has important roles in the growth and/or survival of cancer cells. Cdc37, as a cochaperone, associates kinase clients to Hsp90 and promotes the development of malignant tumors. Disrupting the Hsp90–Cdc37 interaction provides an alternative strategy to inhibit the function of Hsp90 for cancer therapy. Celastrol, as a natural product, can disrupt the Hsp90–Cdc37 interaction and induce degradation of kinase clients. The study conducted here attempted to elucidate the structure–activity relationship of celastrol derivatives as Hsp90–Cdc37 disruptors and to improve the druglike properties. 23 celastrol derivatives were designed, synthesized, and the biological activities and physicochemical properties were determined. The derivative CEL20 showed improved Hsp90–Cdc37 disruption activity, anti-proliferative activities as well as druglike properties. Additionally, CEL20 induced clients degradation, cell cycle arrest and apoptosis in Panc-1 cells. This study can provide reference for the discovery of novel Hsp90–Cdc37 disruptors. 相似文献
4.
For the first time the expression of C3 and CAM in the leaves of different age of Marrubium frivaldszkyanum Boiss, is reported. With increasing leaf age a typical C3 photosynthesis pattern and high transpiration rate were found. In older leaves a shift to CAM occurred and the 24-h transpiration water loss decreased. A correlation was established between leaf area and accumulation of malate. Water loss at early stages of leaf expansion may be connected with the shift to CAM and the water economy of the whole plant. 相似文献
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《Cryobiology》2018
The objective of this study was to evaluate the use of Afp1m as a cryopreservative agent for skin by examining the transplanted skin histological architecture and mechanical properties following subzero cryopreservation. Thirty four (34) rats with an average weight of 208 ± 31 g (mean ± SD), were used. Twenty four (n = 24) rats were equally divided into four groups: (i) immediate non-cryopreserved skin autografts (onto same site), (ii) immediate non-cryopreserved skin autografts (onto different sites), (iii) skin autografts cryopreserved with glycerol for 72 h and (iv) skin autografts cryopreserved with Afp1m for 72 h at −4 °C. Rounded shaped full-thickness 1.5–2.5 cm in diameter skin was excised from backs of rats for the autograft transplantation. Non-cryopreserved or cryopreserved auto skin graft were positioned onto the wound defects and stitched. Non-transplanted cryopreserved and non-cryopreserved skin strips from other ten rats (n = 10) were allowed for comparative biomechanical test. All skin grafts were subjected to histological and mechanical examinations at the end of day 21. Histological results revealed that tissue architecture especially the epidermal integrity and dermal-epidermal junction of the Afp1m cryopreserved skin grafts exhibited better histological appearance, good preservation of tissue architecture and structural integrity than glycerolized skin. However, there was no significant difference among these groups in other histological criteria. There were no significant differences among the 4 groups in skin graft mechanical properties namely maximum load. In conclusion, Afp1m were found to be able to preserve the microstructure as well as the viability and function of the skin destined for skin transplantation when was kept at −4 °C for 72 h. 相似文献
7.
Tillage is known to potentially affect soil quality in various ways. In this study, a soil quality index (SQI) was developed by quantifying several soil attributes either sensitive or insensitive to physical disturbance, using factor analysis as a dimension reduction technique, in order to discriminate different tillage systems. Soil properties including physical (MWD), chemical (pH, organic C, total N, available P and POM contents) and microbial (MBC, MBN, PCM, PNM and three enzymes) parameters were measured to establish a minimum data set (MDS) for the assessment of overall SQI. The soil attributes were determined on samples (0–20 cm depth) collected under moldboard (MP) and disk (DP) plows as conventional tillage (CT), and rotary (RP) and chisel (CP) plows as reduced tillage (RT) systems with a similar plant C input rate and cover crop over a period of six years (2005–2011) in a semi-arid calcareous soil (Calcixerepts) from Central Iran. Results indicated a clear difference in soil quality among the tillage systems with a significant increase of SQI under RT over time, particularly under CP practices. Although RT improved most soil microbial attributes, not all attributes contributed to SQI because of their close interrelationship. The final SQI consisted only of geometric mean of microbial activity (GMA, the square root of the product of PCM and PNM) and geometric mean of enzyme activity (GME, the cube root of the product of enzyme activities). Soil GME and GMA were found to be as key indicators contributing 55% and 36% to SQI, respectively. Therefore, the GME and GMA were the most important indicators effectively discriminating tillage systems, and could be used to monitor the enhancement of soil quality under RT in this semiarid environment. The influence of tillage year on SQI was greater than that of tillage practices. In conclusion, RT systems were characterized by a higher value of SQI, suggesting a good recovery of soil capacity and functions after abandoning CT in the studied area. Smallholder farmers should therefore be aware of the potential for high soil quality in future as a result of continuing RT systems, especially with surface tillage using CP practices. 相似文献
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10.
Olga A. Grishina Irina V. Kirillova Olga E. Glukhova 《Computer methods in biomechanics and biomedical engineering》2016,19(3):297-305
The biomechanical model of human coronary arteries was modified for improving the quality of diagnosis and surgical treatment for coronary heart disease. The problem of hemodynamics in the left coronary artery with multivessel bed disease – 45% stenosis of the anterior descending branch and 75% stenosis of the circumflex branch – was particularly considered. Numerical simulation of the coronary arterial bypass of the main trunk was carried out to estimate the functional condition of the coronary arteries after restoring myocardial blood supply by surgery. 相似文献