An approach to determination of phenolic compounds in seawater using SPME-GC-MS based on SWCNTs coating   总被引：1，自引：0，他引：1  

ZHU Jia  WANG Ying  ZENG Lin 《中国海洋大学学报(英文版)》2016,15(4):655-659

Phenolic compounds have become one kind of the important pollutants of the marine environment. Single-walled Carbon nanotubes, as one-dimensional nano materials, have light weight and perfect hexagonal structure of connections, with many unusual mechanical, chemical and electrical properties. In recent years, with the research of carbon nanotubes and other nano materials, the application prospect is also constantly discussed. In this paper, homemade single-walled carbon nanotubes(SWCNTs) coating was used for establishing an analytical approach to the determination of five kinds of phenolic compounds in seawater using SPME-GC-MS. Optimal conditions: After saturation was conducted with Na Cl, and p H was adjusted to 2.0 with H_2SO_4, the extract was immersed in a water bath at 40 for GC℃-MS determination through 40-min agitating extraction at 500 rmin~(-1) and 3-min desorption at 280℃. The liniearities ranged between 0.01-100 μg L~(-1), and the determination limits ranged between 1.5-10 ngL~(-1). The relative standard deviation(RSD, n = 5) was less than 6.5%. For the phenolic compounds obtained from the spiked recovery test for actual seawater samples, the rates of recovery were 87.5%-101.7%, and the RSDs were less than 8.8%, which met the requirements of determination. Due to its simplicity, high efficiency and low consumption, this approach is suitable for the analysis of trace amounts of phenolic compounds in marine waters.  相似文献   

Effect of stocking density on water quality and (Growth,Body Composition and Plasma Cortisol Content) performance of pen-reared rainbow trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>)     

LIU Qun  HOU Zhishuai  WEN Haishen  LI Jifang  HE Feng  WANG Jinhuan  GUAN Biao  WANG Qinglong 《中国海洋大学学报(英文版)》2016,15(4):667-675

The goal of the study was to examine the effect of stocking density on the water quality of culture area, as well as the growth, body composition and cortisol content of rainbow trout（Oncorhynchus mykiss）. Pen-reared trout were stocked in densities of 40, 60, 80 fish individuals m^-3(4.6, 6.6, 8.6 kg m^-3, SD1, SD2 and SD3 groups, respectively) for 300 days. Compared to the water from SD1 and SD2, that from SD3 exhibited significantly higher NH₄⁺-N content and COD（chemical-oxygen-demand）, and a significant reduction of dissolved oxygen in day 180(40.6 kg m^-3). Stocking density was significantly associated with body weight, standard length, VSI（viscerosomatic index）, CF（condition factor） and FC（food coefficient） in group SD3, particularly in day 240 and day 300(45 or 49.3 kg m^-3). Increased crude fat and decreased crude protein were displayed in high density group when the density reached to 36 kg m^-3. As a cumulative effect of density-related stress, VSI, CF, FC, moisture, and crude protein content varied over time in each density group（SD1, SD2, and SD3）. In summary, trout exhibited a better growth performance in low density(26.3 kg m^-3) than those reared in high densities(36 and 45 kg m^-3). The results indicate that rainbow trout（114.44 g ± 6.21 g, 19.69 cm ± 0.31 cm） initially stocked in 6.6 or 8.6 kg m^-3 should be lightened to less than 36 kg m^-3 after an intensive rearing for 240 days.  相似文献   

Study on biogenic amines in various dry salted fish consumed in China     

WU Yanyan  CHEN Yufeng  LI Laihao  YANG Xianqing  YANG Shaoling  LIN Wanling  ZHAO Yongqiang  DENG Jianchao 《中国海洋大学学报(英文版)》2016,15(4):681-689

This study was carried out to investigate the biogenic amines（BAs）, physicochemical property and microorganisms in dry salted fish, a traditional aquatic food consumed in China. Forty three samples of dry salted fish were gathered from retail and wholesale markets and manufacturers, which had been produced in various regions in China. Cadaverine（CAD） and putrescine（PUT） were quantitatively the most common biogenic amines. About 14% of the samples exceeded the histamine content standards established by the FDA and/or EU. The highest histamine content was found in Silver pomfret（Pampus argenteus）(347.79 mg kg^-1). Five of forty three samples exceeded the acceptable content of TYR(100 mg kg^-1), and 23.26% of dried-salted fish contained high contents of biogenic amines(above 600 mg kg^-1). In addition, species, regions, pickling processes and drying methods made the physicochemical property, microorganisms and biogenic amines in dry salted fish to be different to some extents. The total plate count（TPC） was much higher than that of total halophilic bacteria in all samples. The biogenic amines, physicochemical property and microbiological counts exhibited large variations among samples. Furthermore, no significant correlation between biogenic amines and physicochemical property and TPC was observed. This study indicated that dry salted fish may still present healthy risk for BAs, depending on the processing methods, storage conditions among others.  相似文献   

Advanced glycation endproducts in 35 types of seafood products consumed in eastern China     

WANG Jing  LI Zhenxing  PAVASE Ramesh Tushar  LIN Hong  ZOU Long  WEN Jie  LV Liangtao 《中国海洋大学学报(英文版)》2016,15(4):690-696

Advanced glycation endproducts(AGEs) have been recognized as hazards in processed foods that can induce chronic diseases such as cardiovascular disease, diabetes, and diabetic nephropathy. In this study, we investigated the AGEs contents of 35 types of industrial seafood products that are consumed frequently in eastern China. Total fluorescent AGEs level and Nε-carboxymethyl-lysine(CML) content were evaluated by fluorescence spectrophotometry and gas chromatography-mass spectrometry(GC-MS), respectively. The level of total fluorescent AGEs in seafood samples ranged from 39.37 to 1178.3 AU, and was higher in canned and packaged instant aquatic products that were processed at high temperatures. The CML content in seafood samples ranged from 44.8 to 439.1 mg per kg dried sample, and was higher in roasted seafood samples. The total fluorescent AGEs and CML content increased when seafood underwent high-temperature processing, but did not show an obvious correlation. The present study suggested that commonly consumed seafood contains different levels of AGEs, and the seafood processed at high temperatures always displays a high level of either AGEs or CML.  相似文献   

Market-driven organizational lock-in: A case study of a former first mover     

Rune Njøs  Stig-Erik Jakobsen  Vegar Rosnes 《Norsk geografisk tidsskrift. Norwegian journal of geography》2016,70(3):140-151

ABSTRACT

The article addresses the question of how an innovative firm develops from being a first mover to an innovation laggard and whether this process can be reversed. Informed by the evolutionary perspective and path-dependence theory, the authors explore how a low-tech Norwegian firm in the oil and gas industry has lost its foothold as an innovator. They also employ the concept of organizational architecture as an analytical tool to investigate the agency for breaking organizational paths. Through participant observation and semi-structured interviews, their study revealed that the innovation activity of the case firm is in a state of lock-in following a path-dependence development. Product development in the firm is linked to incremental changes to existing products based on the feedback from the customer, and the process is characterized by knowledge exploitation rather than knowledge exploration. The article adds to the literature on path dependence by identifying how a strong market pull can be a driver for organizational path dependence and lock-in.  相似文献   

Sequence hierarchy in a Mesoproterozoic interior sag basin: from basin fill to reservoir scale,the Tombador Formation,Chapada Diamantina Basin,Brazil          下载免费PDF全文

A. J. C. Magalhães  G. P. Raja Gabaglia  C. M. S. Scherer  M. B. Bállico  F. Guadagnin  E. Bento Freire  L.R. Silva Born  O. Catuneanu 《Basin Research》2016,28(3):393-432

The Tombador Formation exhibits depositional sequence boundaries placed at the base of extensive amalgamated fluvial sand sheets or at the base of alluvial fan conglomeratic successions that indicate basinward shifts of facies. The hierarchy system that applies to the Tombador Formation includes sequences of different orders, which are defined as follows: sequences associated with a particular tectonic setting are designated as ‘first order’ and are separated by first‐order sequence boundaries where changes in the tectonic setting are recorded; second‐order sequences represent the major subdivisions of a first‐order sequence and reflect cycles of change in stratal stacking pattern observed at 10² m scales (i.e., 200–300 m); changes in stratal stacking pattern at 10¹ m scales indicate third‐order sequences (i.e., 40–70 m); and changes in stratal stacking pattern at 10⁰ m scales are assigned to the fourth order (i.e., 8–12 m). Changes in palaeogeography due to relative sea level changes are recorded at all hierarchical levels, with a magnitude that increases with the hierarchical rank. Thus, the Tombador Formation corresponds to one‐first‐order sequence, representing a distinct intracratonic sag basin fill in the polycyclic history of the Espinhaço Supergroup in Chapada Diamantina Basin. An angular unconformity separates fluvial‐estuarine to alluvial fan deposits and marks the second‐order boundary. Below the angular unconformity the third‐order sequences record fluvial to estuarine deposition. In contrast, above the angular unconformity these sequences exhibit continental alluvial successions composed conglomerates overlain by fluvial and eolian strata. Fourth‐order sequences are recognized within third‐order transgressive systems tract, and they exhibit distinct facies associations depending on their occurrence at estuarine or fluvial domains. At the estuarine domain, they are composed of tidal channel, tidal bar and overlying shoreface heterolithic strata. At the fluvial domain the sequences are formed of fluvial deposits bounded by fine‐grained or tidal influenced intervals. Fine grained intervals are the most reliable to map in fourth‐order sequences because of their broad laterally extensive sheet‐like external geometry. Therefore, they constitute fourth‐order sequence boundaries that, at the reservoir approach, constitute the most important horizontal heterogeneity and, hence, the preferable boundaries of production zones. The criteria applied to assign sequence hierarchies in the Tombador Formation are based on rock attributes, are easy to apply, and can be used as a baseline for the study of sequence stratigraphy in Precambrian and Phanerozoic basins placed in similar tectonic settings.  相似文献   

Unraveling the Peruvian Phase of the Central Andes: stratigraphy,sedimentology and geochronology of the Salar de Atacama Basin (22°30–23°S), northern Chile          下载免费PDF全文

Sebastián Bascuñán  César Arriagada  Jacobus Le Roux  Katja Deckart 《Basin Research》2016,28(3):365-392

The Salar de Atacama Basin holds important information regarding the tectonic activity, sedimentary environments and their variations in northern Chile during Cretaceous times. About 4000 m of high‐resolution stratigraphic columns of the Tonel, Purilactis and Barros Arana Formations reveal braided fluvial and alluvial facies, typical of arid to semi‐arid environments, interrupted by scarce intervals with evaporitic, aeolian and lacustrine sedimentation, displaying an overall coarsening‐upward trend. Clast‐count and point‐count data evidence the progressive erosion from Mesozoic volcanic rocks to Palaeozoic basement granitoids and deposits located around the Cordillera de Domeyko area, which is indicative of an unroofing process. The palaeocurrent data show that the source area was located to the west. The U/Pb detrital zircon geochronological data give maximum depositional ages of 149 Ma for the base of the Tonel Formation (Agua Salada Member), and 107 Ma for its middle member (La Escalera Member); 79 Ma for the lower Purilactis Formation (Limón Verde Member), and 73 Ma for the Barros Arana Formation. The sources of these zircons were located mainly to the west, and comprised from the Coastal Cordillera to the Precordillera. The ages and pulses record the tectonic activity during the Peruvian Phase, which can be split into two large events; an early phase, around 107 Ma, showing uplift of the Coastal Cordillera area, and a late phase around 79 Ma indicating an eastward jump of the deformation front to the Cordillera de Domeyko area. The lack of internal deformation and the thicknesses measured suggest that deposition of the units occurred in the foredeep zone of an eastward‐verging basin. This sedimentation would have ended with the K‐T phase, recognized in most of northern Chile.  相似文献   

Glacier changes in the eastern Nyainqêntanglha Range of Tibetan Plateau from 1975 to 2013     

JI Qin  YANG Tai-bao  HE Yi  CHEN Jie  WANG Kai 《山地科学学报》2016,13(4):682-692

Maritime-type glaciers in the eastern Nyainqêntanglha Range, located in the southeastern part of the Tibetan Plateau, are an important water source for downstream residents and ecological systems. To better understand the variability of glaciers in this region, we used the band ratio threshold(TM3/TM5 for the Landsat TM /ETM+ and TM4/TM6 for Landsat OLI) to extract glacier outlines in ~1999 and ~2013. After that, we also generated a series of glacier boundaries and monitored glacier variations in the past 40 years with the help of the Chinese Glacier Inventory data(1975) and Landsat TM, ETM+ and OLI data. The total glacier area decreased by 37.69 ± 2.84% from 1975 to 2013. The annual percentage area change(APAC) was ~1.32% a-1 and ~1.29% a-1 in the periods 1975-1999 and 1999-2013, respectively. According to the lag theory, the reaction time is probably about 10 years and we discuss the variations of temperature and precipitation between 1965 and 2011. Temperature and precipitation increased between 1965 and 2011 at a rate of 0.34°C /10 a and 15.4 mm/10 a, respectively. Extensive meteorological data show that the glacier shrinkage rate over the period may be mainly due to increasing air temperature, while the increasing precipitation partly made up for the mass loss of glacier ice resulting from increasing temperature may also lead to the low APAC between 1999 and 2013. The lag theory suggests that glacier shrinkage may accelerate in the next 10 years. Small glaciers were more sensitive to climate change, and there was a normal distribution between glacier area and elevation. Glaciers shrank in all aspects, and south aspects diminished faster than others.  相似文献   

Preliminary studies on the dynamic prediction method of rainfall-triggered landslide   总被引：1，自引：0，他引：1  

Yue-li Chen  De-hui Chen  Ze-chun Li  Jun-bao Huang 《山地科学学报》2016,13(10):1735-1745

Rainfall-triggered landslides have posed significant threats to human lives and property each year in China. This paper proposed a meteorologicalgeotechnical early warning system GRAPES-LFM(GRAPES: Global and Regional Assimilation and Pr Ediction System; LFM: Landslide Forecast Model),basing on the GRAPES model and the landslide predicting model TRIGRS(Transient Rainfall Infiltration and Grid-based Regional Slope-Stability Model) for predicting rainfall-triggered landslides.This integrated system is evaluated in Dehua County,Fujian Province, where typhoon Bilis triggered widespread landslides in July 2006. The GRAPES model runs in 5 km×5 km horizontal resolution, and the initial fields and lateral boundaries are provided by NCEP(National Centers for Environmental Prediction) FNL(Final) Operational Global Analysis data. Quantitative precipitation forecasting products of the GRAPES model are downscaled to 25 m×25 m horizontal resolution by bilinear interpolation to drive the TRIGRS model. Results show that the observed areas locate in the high risk areas, and the GRAPES-LFM model could capture about 74% of the historical landslides with the rainfall intense 30mm/h. Meanwhile, this paper illustrates the relationship between the factor of safety(FS) and different rainfall patterns. GRAPES-LFM model enables us to further develop a regional, early warning dynamic prediction tool of rainfall-induced landslides.  相似文献   

Long-range precipitation forecasts using paleoclimate reconstructions in the western United States     

Christopher Allen CARRIER  Ajay KALRA  Sajjad AHMAD 《山地科学学报》2016,13(4):614-632

Long-range precipitation forecasts are useful when managing water supplies.Oceanicatmospheric oscillations have been shown to influence precipitation.Due to a longer cycle of some of the oscillations,a short instrumental record is a limitation in using them for long-range precipitation forecasts.The influence of oscillations over precipitation is observable within paleoclimate reconstructions;however,there have been no attempts to utilize these reconstructions in precipitation forecasting.A data-driven model,KStar,is used for obtaining long-range precipitation forecasts by extending the period of record through the use of reconstructions of oscillations.KStar is a nearest neighbor algorithm with an entropy-based distance function.Oceanic-atmospheric oscillation reconstructions include the El Nino-Southern Oscillation(ENSO),the Pacific Decadal Oscillation(PDO),the North Atlantic Oscillation(NAO),and the Atlantic Multi-decadal Oscillation(AMO).Precipitation is forecasted for 20 climate divisions in the western United States.A 10-year moving average is applied to aid in the identification of oscillation phases.A lead time approach is used to simulate a one-year forecast,with a 10-fold cross-validation technique to test the models.Reconstructions are used from 1658-1899,while the observed record is used from 1900-2007.The model is evaluated using mean absolute error(MAE),root mean squared error(RMSE),RMSE-observations standard deviation ratio(RSR),Pearson’s correlation coefficient(R),NashSutcliffe coefficient of efficiency(NSE),and linear error in probability space(LEPS) skill score(SK).The role of individual and coupled oscillations is evaluated by dropping oscillations in the model.The results indicate ’good’ precipitation estimates using the KStar model.This modeling technique is expected to be useful for long-term water resources planning and management.  相似文献