Comparison of loss on ignition and thermal analysis stepwise methods for determination of sedimentary organic matter     

Gretel Frangipane  Mario Pistolato  Emanuela Molinaroli  Stefano Guerzoni  Davide Tagliapietra 《水产资源保护:海洋与淡水生态系统》2009,19(1):24-33

• 1. Loss on ignition (LOI) is a widely used method to estimate organic matter (OM) in the sediment of marine and freshwater ecosystems. Thermogravimetric‐differential thermal analysis (TG‐DTA) of organic species provides information on thermal reactions, the amount and properties of clay structural water, organic species and carbonates.
• 2. The accuracy of LOI compared with that of TG‐DTA was evaluated in 33 sediment samples from the Lagoon of Venice (Italy).
• 3. In all tests conducted with TG‐DTA the mass loss of OM and the loss of clay structural water (LCSW) from oxidized samples were measured. The mass loss of OM at 350°C (TG‐DTA 350 OM) and the total extraction of organic matter at 567°C (TEOM) calculated from the difference between natural state samples and oxidized samples highlight the presence of both thermally labile and thermally stable substances.
• 4. The grain size data of sediment samples from the Lagoon shows a variable distribution between slightly muddy sand and mud. Loss of clay structural water at 350°C (LCSW 350) and total extraction of clay structural water at 567°C (TECSW) both estimated by TG‐DTA on oxidized samples, were found to correspond approximately to 6% and 10%, respectively of the clay fraction (<4 µm). This percentage may be used to correct LOI measurements of OM in sediments with high clay content.
• 5. LOI 350 (loss on ignition at 350°C) and LOI 550 (loss on ignition at 550°C) proved to be ～80% and ～200%, respectively, of total extraction of mass loss at 350°C (TG‐DTA 350 tot) and at 567°C (TEML) estimated by TG‐DTA on natural samples, meaning that the LOI 550 value represents a significant overestimate. The difference between the LOI 550 and TEML values indicates that the mass loss excess (MLE) may be accounted for by losses due to breakdown of carbonates.

Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Development and validation of a robust KASP marker for zt2 locus in faba bean (Vicia faba)     

Stefano Zanotto  Albert Vandenberg  Hamid Khazaei 《Plant Breeding》2020,139(2):375-380

Faba bean has the potential to become a key food and feed protein crop in many areas of the world. The presence of tannins in its seed coat has limited the deployment of this crop as feed and food. The expression of either of the two recessive genes, zt1 and zt2, causes a great reduction of tannins from the seed coat and results in a white flower phenotype. Molecular markers linked to these loci are fundamental tools for speeding up the breeding of low-tannin varieties. The main aim of this study was to develop and validate a robust molecular marker linked to the zt2 locus. We used 176 recombinant inbred lines of the Disco/2 × ILB 938/2 cross at F₆ and genotyped those using 257 SNP (single nucleotide polymorphism) markers. An SNP marker associated with zt2 locus was found on faba bean chromosome 3 and was used to develop a high-throughput low-cost KASP (kompetitive allele-specific PCR) marker. The KASP marker can successfully discriminate low-tannin faba beans carrying zt2 from those carrying zt1 and wild-type alleles.  相似文献   

Effect of Genotype on the Sprouting of Pomegranate (<Emphasis Type="Italic">Punica granatum</Emphasis> L.) Seeds as a Source of Phenolic Compounds from Juice Industry by-Products     

Beatrice Falcinelli  Ombretta Marconi  Stefano Maranghi  Stanley Lutts  Adolfo Rosati  Franco Famiani  Paolo Benincasa 《Plant foods for human nutrition (Dordrecht, Netherlands)》2017,72(4):432-438

Pomegranate (Punica granatum L.) fruits are used mainly by the juice industry, for which seeds are a by-product to be disposed of, though they could potentially be a source of bioactive compounds. In this work, germination (total germination percentage, G; mean germination time, MGT; time to reach 80% of germination, TG80; seedling shoot length, fresh weight and dry matter), and nutritional value (total phenolics, TP; total flavonoids, TF; total non-tannins, TNT; antioxidant activities) of pomegranate seeds and sprouts were determined on four commercial pomegranate cultivars (Akko, Dente di Cavallo, Mollar de Elche and Wonderful). Seeds were removed from ripe fruits and incubated in plastic trays containing sterile cotton wetted with distilled water. Sprout shoots were harvested when they reached the complete cotyledon expansion, i.e., the ready-to-eat stage. Akko showed the best germination performance (G = 98%; MGT = 14 days after sowing, DAS; TG80 = 16 DAS), followed by Mollar de Elche. Sprouting dramatically increased TP, TF, TNT and antioxidant activity in all genotypes, with the highest values recorded in Mollar de Elche and Dente di Cavallo. Overall, based on germination performance, Akko and Mollar de Elche would be the best cultivars for sprouting. Sprouting pomegranate seeds appears to be a suitable way of utilizing by-products of the juice industry to obtain bioactive compounds.  相似文献   

Standardization of canine meningioma grading: Validation of new guidelines for reproducible histopathologic criteria     

Sara Belluco  Giuseppe Marano  Thibaut Lurier  Giancarlo Avallone  Chiara Brachelente  Stefano Di Palma  Roberta Rasotto  Kerstin Baiker  Andreas Beineke  Anna Oevermann  Frauke Seehusen  Fabiano José Ferreira de Sant'Ana  Patrizia Boracchi  Martí Pumarola  Maria Teresa Mandara 《Veterinary and comparative oncology》2023,21(4):685-699

Canine meningiomas are currently graded using the human grading system. Recently published guidelines have adapted the human grading system for use in dogs. The goal of this study was to validate the new guidelines for canine meningiomas. To evaluate the inter-observer agreement, 5 veterinary surgical pathologists graded 158 canine meningiomas following the human grading system alone or with the new guidelines. The inter-observer agreement for histologic grade and each of the grading criteria (mitotic grade, invasion, spontaneous necrosis, macronucleoli, small cells, hypercellularity, pattern loss and anaplasia) was evaluated using the Fleiss kappa index. The diagnostic accuracy (sensitivity and specificity) was assessed by comparing the diagnoses obtained with the 2 grading systems with a consensus grade (considered the reference classification). The consensus histologic grade was obtained by agreement between 4 experienced veterinary neuropathologists following the guidelines. Compared with the human grading alone, the canine-specific guidelines increased the inter-observer agreement for: histologic grade (κ = 0.52); invasion (κ = 0.67); necrosis (κ = 0.62); small cells (κ = 0.36); pattern loss (κ = 0.49) and anaplasia (κ = 0.55). Mitotic grade agreement remained substantial (κ = 0.63). The guidelines improved the sensitivity in identifying grade 1 (95.6%) and the specificity in identifying grade 2 (96.2%) meningiomas. In conclusion, the new grading guidelines for canine meningiomas are associated with an overall improvement in the inter-observer agreement and higher diagnostic accuracy in diagnosing grade 1 and grade 2 meningiomas.  相似文献