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排序方式: 共有69条查询结果,搜索用时 31 毫秒
1.
K. David Hyrenbach Zora McGinnis Kathleen Page Dan Rapp F. David Horgen Jennifer M. Lynch 《水产资源保护:海洋与淡水生态系统》2021,31(2):408-419
- Although the frequency of occurrence of plastic ingestion in the large-sized dolphinfish and tunas taken by the Hawai'i longline fishery is very low (frequency of occurrence < 5% of sampled individuals), the ingestion of plastic in smaller-sized specimens caught with pole-and-line gear by commercial and recreational fishers has not been investigated.
- This study examined ingestion of >0.25 mm marine plastic debris (MPD) by four predatory fish species caught by commercial fishers around the Main Hawaiian Islands, and documented ingestion in three species: 85.7% of albacore tuna (n = 7), 40.0% of skipjack tuna (n = 10) and 12.5% of dolphinfish (n = 8).
- Yellowfin tuna (n = 10) did not contain any MPD, probably owing to the high proportion of empty stomachs (60%).
- For skipjack tuna, the frequency of occurrence of MPD ingestion was significantly higher for the smaller-sized specimens caught with pole-and-line (40%), compared with the larger-sized specimens caught with longlines (0%).
- For dolphinfish, the frequency of occurrence of MPD ingestion was similar for the similar-sized specimens caught with pole-and-line and with longlines.
- The ingested MPD items were micro–meso plastics, between 1 and 25 mm. While most ingested items were fragments, albacore also ingested line and skipjack also ingested sheets.
- The predatory fishes ingested light MPD items that float in sea water, but there were species-specific differences in their polymer composition: albacore contained more polypropylene and polyethylene, and skipjack contained more elastomers, characterized by a high percentage of ester plasticizers.
- Altogether, these results suggest that albacore and skipjack tunas ingest plastic of different types and polymers. Yet more research is needed to understand how differences in vertical distribution, foraging ecology and diet influence the MPD sampled by these predatory fish species.
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二维相关红外光谱分析鉴别不同产地黑木耳 总被引:1,自引:0,他引:1
不同产地黑木耳的营养成分含量存在差异,因此对黑木耳的产地鉴别具有实用价值。选取8个不同产地的黑木耳,采用傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FT-IR)和二维相关红外光谱(two-dimensional correlation infrared spectroscopy,2D-IR),对不同样本的2D-IR谱图进行处理和分析,并结合系统聚类分析以鉴别黑木耳的不同产地。结果显示,不同产地黑木耳的傅里叶变换红外光谱整体特征极为相似,偏相关系数的最小值为0.955,不能用于区分黑木耳的产地。不同产地黑木耳在1 730~1 400 cm-1、1 350~1 040 cm-1以及1 030~900 cm-1范围内的二维相关红外光谱中自动峰数目不同,它们之间的自动峰和交叉峰的强度也有较大差异;对1 700~950 cm-1范围内的FT-IR光谱进行系统聚类分析,不同产地黑木耳都得到正确归类。结果表明,二维相关红外光谱分析,结合系统聚类分析能够简单、快速、无损地鉴别不同产地黑木耳。 相似文献
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The pomaces obtained after cold pressing oil production from oil seeds can be regarded as a source of many valuable nutrients such as unsaturated fatty acids, dietary fibre and antioxidants. The aim of the research was to determine the effect of five oil pomaces from black seed, hemp, pumpkin, milk thistle and primrose on the structure of gluten proteins. The model dough was supplemented with 3%, 6%, and 9% of the pomaces. Structural changes in gluten proteins were studied using Fourier transform Raman spectroscopy (FT-Raman) and Fourier transform infrared spectroscopy (FT-IR). Additionally, chemical composition of the pomaces was determined. Changes observed in the gluten structure resulting from the model dough supplementation with oil pomaces allow the pomace to be divided into two groups depending on the type and amount of fatty acids present in the pomaces. If the pomace contains a low number of fatty acids (black seed and pumpkin), pseudo-β-sheets are formed from β-turns and antiparallel-β-sheets in the gluten network. If the pomace contains a high number of fatty acids, non-aggregated β-structures are observed. Although the pomaces contain considerable amount of dietary fibre and polyphenols, comparison of the observed structural changes in gluten network with pomaces’ chemical composition indicates that the changes are connected with presence of fatty acids. 相似文献
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ABSTRACT This study deals with the influence of electron beam irradiation (EBI) on the wettability of Norway spruce surface samples. To evaluate this possible effect in detail, the changes in chemistry and wood structure were analysed using the methods of IR spectroscopy and Scanning Electron Microscopy (SEM). The surface wettability was determined by the contact angle measurement method. The results of infrared spectra show decreased relative numbers of available hydrophilic groups (e.g. hydroxyl and carbonyl groups) in the wood surfaces due to the electron beam irradiation. This behaviour is consistent with the values from the surface wettability measurements. Structural differences of the wood surfaces after electron beam irradiation were not detectable. Based on these findings pre-treatment of wood surfaces for industrial usages can be a potential field of application of this technology. 相似文献
6.
Hillary Righini Ornella Francioso Michele Di Foggia Antera Martel Quintana Roberta Roberti 《Marine drugs》2020,18(12)
Phycobiliproteins (PBPs) are proteins of cyanobacteria and some algae such as rhodophytes. They have antimicrobial, antiviral, antitumor, antioxidative, and anti-inflammatory activity at the human level, but there is a lack of knowledge on their antifungal activity against plant pathogens. We studied the activity of PBPs extracted from Arthrospira platensis and Hydropuntia cornea against Botrytis cinerea, one of the most important worldwide plant-pathogenic fungi. PBPs were characterized by using FT-IR and FT-Raman in order to investigate their structures. Their spectra differed in the relative composition in the amide bands, which were particularly strong in A. platensis. PBP activity was tested on tomato fruits against gray mold disease, fungal growth, and spore germination at different concentrations (0.3, 0.6, 1.2, 2.4, and 4.8 mg/mL). Both PBPs reduced fruit gray mold disease. A linear dose–response relationship was observed for both PBPs against disease incidence and H. cornea against disease severity. Pathogen mycelial growth and spore germination were reduced significantly by both PBPs. In conclusion, PBPs have the potential for being also considered as natural compounds for the control of fungal plant pathogens in sustainable agriculture. 相似文献
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红外光谱结合多元线性回归法快速测定木塑复合材料中木粉含量 总被引:1,自引:0,他引:1
采用KBr压片法对杉木/聚丙烯(PP)复合材料样品进行了红外光谱分析,确定杉木特征吸收谱带为1740~1730、1610~1590、1270~1260、1060~1050以及1040~1030 cm-1,以PP在1377 cm-1处吸收强度(I)为内标,对木塑复合材料(WPC)中木粉含量和杉木特征峰相对吸收强度进行相关性分析,并采用逐步多元线性回归法建立木粉含量与相对峰强间的多元线性回归方程。结果表明,选取I(1060-1050)/I1377、I(1270-1260)/I1377为回归变量建立的二元线性回归方程和以I(1060-1050)/I1377、I(1040-1030)/I1377及I(1270-1260)/I1377为回归变量建立的三元线性回归方程,具有较高的预测精度。木粉含量的预测值和参照值之间具有强烈的相关性,校正决定系数(R2c)超过0.98,验证决定系数(R2p)超过0.96。外部验证结果表明,线性回归方程预测准确性较高,预测相对偏差范围为0.9%至7.4%,其中三元线性回归方程预测准确性稍好于二元线性回归方程。 相似文献
8.
改性白果壳对水溶液中重金属镉的吸附研究 总被引:3,自引:2,他引:1
为实现农林废弃物的资源化利用和开辟廉价、高效的重金属吸附剂,利用1%KMnO4溶液对白果壳进行化学改性,制备成KMnO4改性白果壳(命名为WSK),用于水溶液中Cd2+的吸附,研究温度、pH、反应时间、初始Cd2+浓度4个因素对WSK吸附Cd2+的影响,并通过模型拟合、电镜扫描(SEM)和红外光谱(FTIR)分析,对吸附机理进行了初步探讨。结果表明,WSK是一种理想的Cd2+吸附剂,其吸附性能受温度、pH、反应时间、Cd2+初始浓度的影响。吸附量与体系温度呈正相关,温度越高吸附量越大;随pH的增加吸附量先升高后降低,pH为5.5时,吸附效果最佳;在60 min后基本达到吸附平衡;随着Cd2+初始浓度的升高,WSK对水中Cd2+的吸附量逐渐增加,当Cd2+浓度为300 mg·L-1时,去除率为94.49%,基本达到吸附饱和。WSK对水中Cd2+的吸附符合Freundlich模型,决定系数R2为0.94,最大吸附量为119.76mg·g-1;吸附过程符合二级动力学吸附模型,R2为0.999 5。SEM照片显示WSK表面呈多孔结构,增加了WSK的比表面积、孔容及表面吸附位点,这有助于提高其吸附性能。红外光谱图分析表明,WSK主要靠-OH、-COO-、-NH-、C=O、-P=O、-CH-等离子活性官能基团与Cd2+配位结合,其中-COO-起重要作用。 相似文献
9.
Vigentini Ileana Grassi Silvia Sinelli Nicoletta Di Egidio Valentina Picozzi Claudia Foschino Roberto Casiraghi Ernestina 《农业科学与技术》2014,(6):475-486
The aim of this work was to verify the potential of infrared (IR) spectroscopy in near and mid regions to detect the beginning of the malolactic fermentation (MLF) occurring in a model-wine and the further cells autolysis. MLF in wine is a secondary biotransformation due to lactic acid bacteria that usually occurs spontaneou,;ly or after starter inoculation at the end of alcoholic fermentation. Nowadays, it is desirable to supply winemakers with a new rapid and non-destructive approach to monitor MLF progress and 1R spectroscopy technology appears to be suitable for this purpose. The transformation of L-malic acid into L-lactic acid was carried out by inoculating a synthetic wine with an Oenococcus oeni culture and it was monitored through microbiological and chemical methods. At the same time, Fourier transform near infrared (FT-NIR) spectral data, in diffusive transflection mode using an optic probe, and FT-IR spectra, using an germanium crystal attenuated total reflectance (ATR) cell, were collected. Principal component analysis of the spectra was able to identify absorption bands related to the key molecular modifications that took place during the L-malic acid transformation. Thus, the samples were discriminated according to the fermentation phase. Although this study is a preliminary approach, results confirm that near infrared (NIR) and mid infrared (MIR) spectroscopy could be successfully applied to detect the start of MLF and the autolysis of the lactic acid bacteria (LAB) cells. 相似文献
10.
Bai-Liang XueMing-Fei Li Feng Xu Run-Cang Sun Gwynn Jones 《Industrial Crops and Products》2012,36(1):209-216
Pinus yunnanensis was subjected to water-bath and microwave treatments in 1% NaOH aqueous solutions at 100 °C with various ratios of bath heating time to microwave heating time (0/120, 20/100, 40/80, 60/60, 80/40, 100/20 and 120/0 min). The lignins dissolved in the alkali liquors were separated and purified, and their physicochemical features were comparatively characterized by sugar analysis, GPC, FT-IR, 13C and HSQC NMR, as well as thermogravimetric analysis (TGA). The results showed that the lignin fractions extracted with microwave heating (20-120 min) had high molecular weights and polydispersities (Mw 3150-5710 g/mol, Mn 2130-3020 g/mol, Mw/Mn 1.48-2.00) as compared to those prepared without microwave heating (Mw 3080 g/mol, Mn 2080 g/mol, Mw/Mn 1.48). The most striking characteristic of all lignin fractions was the almost absence of associated sugars (0.16-3.25%). The TGA results indicated that the thermal stability of the lignin fraction increased with the increment of the molecular weight. FT-IR and NMR spectra suggested that the lignin fractions showed similar structures which were mainly composed of guaiacyl (G) and minor amounts of p-hydroxyphenyl (H) units. Moreover, HSQC NMR spectrum of a typical lignin fraction (prepared with microwave heating for 120 min) revealed that it contained dominant amounts of β-O-4′ linkages (64.6%) and phenylcoumaran (β-5′) substructures (25.8%) together with small amounts of resinol (β-β′) substructures (6.7%) and coniferyl alcohol end groups (2.9%). 相似文献