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101.
Loredana Incarnato Paola Scarfato Domenico Acierno Maria Rosaria Milana Roberta Feliciani 《应用聚合物科学杂志》2003,89(7):1768-1778
In this work the effect of three processing cycles on the physical properties of polypropylene (PP) was studied and related to the changes in the structure (molecular weight, molecular weight distribution, morphology) occurring during recycling. In order to simulate both the use and the recycling process of PP in the laboratory, PP pellets were contaminated with three model substances and submitted to three cycles of processing by injection molding. The bars for testing were produced from virgin and recycled polymers. The amount of degradation occurring during the reprocessing was estimated by means of viscosity and gel permeation chromatography measurements. Differential scanning calorimetry and scanning electron microscopy analyses were performed to investigate the crystallization behavior and the morphology of virgin and recycled PP. In order to obtain information on the structural organization and mobility of the amorphous phase, a dynamic mechanical thermal analysis and measurements of the transport properties were carried out. The results obtained were attributed to the different structural organization of the bars in relation to the number of processing cycles and contamination. Part of the work was focused on the recyclability of PP for food packaging applications, considering the residual contamination and migrational behavior after repeated processing cycles. In particular, the relationships existing between reprocessing, the residual amounts of contaminants, and the migrational behavior were investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1768–1778, 2003 相似文献
102.
103.
Censi P Zuddas P Randazzo LA Tamburo E Speziale S Cuttitta A Punturo R Aricò P Santagata R 《Environmental science & technology》2011,45(15):6262-6267
Rapid volcanic eruptions quickly ejecting large amounts of dust provoke the accumulation of heavy metals in people living in surrounding areas. Analyses of bronchoalveolar lavage samples (BAL) collected from people exposed to the paroxysmal 2001 Etna eruption revealed a strong enrichment of many toxic heavy metals. Comparing the BAL to the dust composition of southeastern Sicily, we found that only V, Cr, Mn, Fe, Co, and U enrichment could be related to the volcanic event, whereas Ni, Cu, Cd, and Pb contents come from the dissolution of particles of anthropogenic origin. Furthermore, the nature of these inhaled anthropogenic particles was revealed by anomalous La and partially Ce concentrations in BAL that were consistent with a mixture of road dust and petroleum refinery emissions. Our results indicate that trace element distribution in BAL is a suitable tracer of human exposure to different sources of inhaled atmospheric particulates, allowing investigations into the origin of source materials inhaled by people subjected to atmospheric fallout. 相似文献
104.
Effects of a diet containing dried grape pomace on blood metabolites and milk composition of dairy cows 下载免费PDF全文
105.
Serena Bianchi Leonardo Mancini Diana Torge Loredana Cristiano Antonella Mattei Giuseppe Varvara Guido Macchiarelli Enrico Marchetti Sara Bernardi 《International journal of molecular sciences》2021,22(16)
Understanding the biological and morphological reactions of human cells towards different dentinal derivate grafting materials is fundamental for choosing the type of dentin for specific clinical situations. This study aimed to evaluate human periodontal ligament fibroblasts (hPLF) cells exposed to different dentinal derivates particles. The study design included the in vitro evaluation of mineralized dentine (SG), deproteinized and demineralized dentine (DDP), and demineralized dentine (TT) as test materials and of deproteinized bovine bone (BIOS) as the positive control material. The materials were kept with the hPLF cell line, and the evaluations were made after 24 h, 72 h, and 7 days of in vitro culture. The evaluated outcomes were proliferation by using XTT assays, the morphological characteristics by light microscopy (LM) and by the use of scanning electron microscopy (SEM), and adhesion by using confocal microscopy (CLSM). Overall, the experimental materials induced a positive response of the hPLFs in terms of proliferation and adhesion. The XTT assay showed the TT, and the SG induced significant growth compared to the negative control at 7 days follow-up. The morphological data supported the XTT assay: the LM observations showed the presence of densely packed cells with a modified shape; the SEM observations allowed the assessment of how fibroblasts exposed to DDP and TT presented cytoplasmatic extensions; and SG and BIOS also presented the thickening of the cellular membrane. The CLMS observations showed the expression of the proliferative marker, as well as and the expression of cytoskeletal elements involved in the adhesion process. In particular, the vinculin and integrin signals were stronger at 72 h, while the actin signal remained constantly expressed in all the follow-up of the sample exposed to SG material. The integrin signal was stronger at 72 h, and the vinculin and actin signals were stronger at 7 days follow-up in the sample exposed to DDP material. The vinculin and integrin signals were stronger at 72 h follow-up in the sample exposed to TT material; vinculin and integrin signals appear stronger at 24 h follow-up in the sample exposed to BIOS material. These data confirmed how dentinal derivates present satisfying biocompatibility and high conductivity and inductivity properties fundamental in the regenerative processes. Furthermore, the knowledge of the effects of the dentin’s degree of mineralization on cellular behavior will help clinicians choose the type of dentine derivates material according to the required clinical situation. 相似文献
106.
Anna Maria Ferrini Veruscka Mannoni Elisabetta Suffredini Loredana Cozzi Luciana Croci 《Food Analytical Methods》2008,1(3):164-170
Ninety-two Vibrio strains isolated over a period of 9 years from different sources (national and imported fishery products, shellfish, seawater
from aquaculture settings, etc.) and belonging mostly to two species relevant for human health and fish pathology, V. parahaemolyticus and V. alginolyticus, were tested for resistance to different antibacterials using the standard disk diffusion test (five antibacterials: ampicillin,
sulfamethoxazole, tetracycline, trimethoprim/sulfamethoxazole and chloramphenicol) and the Minimum Inhibitory Concentrations
method (six antibacterial families: β-lactams, tetracyclines, chloramphenicol, aminoglycosides, quinolones, trimethoprim/sulfamethoxazole)
providing consistent results. The analysis performed by standard disk diffusion test showed resistance to ampicillin in 82%
of the strains, whereas 7% were resistant to sulfamethoxazole, 3% to tetracycline, and 1% to trimethoprim/sulfamethoxazole;
no strain was found to be resistant to chloramphenicol. The results obtained by the MIC tests, because of the absence of established
breakpoints for some antibacterials, were not readily interpretable for all substances, but showed no statistically significant
difference to the results obtained by the standard disk diffusion test. Beside these results, high MIC90 values (128 μg ml−1 and above) were obtained for kanamycin and streptomycin, indicating that high concentrations of these antibacterials were
required to inhibit the growth of the strains. Strains exhibiting resistance or intermediate resistance to two or more antibacterials
represented 15% of the total and included, beside resistance to ampicillin, resistance to sulfamethoxazole or, for V. parahaemolyticus isolates, tetracycline. Interestingly, differences in the mechanism of resistance to β-lactams were detected between the
species V. parahaemolyticus and V. alginolyticus. 相似文献
107.
Rapid detection of Paenibacillus larvae from honey and hive samples with a novel nested PCR protocol 总被引:4,自引:0,他引:4
Lauro FM Favaretto M Covolo L Rassu M Bertoloni G 《International journal of food microbiology》2003,81(3):195-201
The bacterial pathogen Paenibacillus larvae is the causative agent of American foulbrood disease in honeybees (Apis mellifera). A touchdown nested PCR protocol was developed to detect the presence of P. larvae spores directly in honey and hive samples. This approach allows early discovery of the bacteria even at concentrations below pathogenic levels, opening the door to new prophylactic approaches against American foulbrood and real-time epidemiological studies. 相似文献
108.
Assay of Sudan I contamination of foodstuff by atmospheric pressure chemical ionization tandem mass spectrometry and isotope dilution 总被引:1,自引:0,他引:1
Food safety represents one of the main issues of national and international agencies appointed to health control. In April 2003, a French agency disclosed that powdered or smashed hot chili pepper imported from India and Pakistan was heavily contaminated with a carcinogenic azo dye known as Sudan I. This paper deals with a modern approach for assaying the content of this colorant in foodstuff down to a limit of a few tens of parts per billion. The isotope dilution method combined with APCI tandem mass spectrometry was used. The internal standard, 1-(d5-phenylazo)-2-naphthalenol, was obtained by simple chemistry, and its structure was determined by 1H NMR spectroscopy. The mass spectrometric method is more sensitive than the HPLC approach by a factor of 20. 相似文献
109.
Andreea Iren Serban Loredana Stanca Ovidiu Ionut Geicu Anca Dinischiotu 《International journal of molecular sciences》2015,16(9):20100-20117
Advanced glycation end products (AGEs) can activate the inflammatory pathways involved in diabetic nephropathy. Understanding these molecular pathways could contribute to therapeutic strategies for diabetes complications. We evaluated the modulation of inflammatory and oxidative markers, as well as the protective mechanisms employed by human embryonic kidney cells (HEK 293) upon exposure to 200 μg/mL bovine serum albumine (BSA) or AGEs–BSA for 12, 24 and 48 h. The mRNA and protein expression levels of AGEs receptor (RAGE) and heat shock proteins (HSPs) 27, 60 and 70, the activity of antioxidant enzymes and the expression levels of eight cytokines were analysed. Cell damage via oxidative mechanisms was evaluated by glutathione and malondialdehyde levels. The data revealed two different time scale responses. First, the up-regulation of interleukin-6 (IL-6), HSP 27 and high catalase activity were detected as early as 12 h after exposure to AGEs–BSA, while the second response, after 24 h, consisted of NF-κB p65, RAGE, HSP 70 and inflammatory cytokine up-regulation, glutathione depletion, malondialdehyde increase and the activation of antioxidant enzymes. IL-6 might be important in the early ignition of inflammatory responses, while the cellular redox imbalance, RAGE activation and NF-κB p65 increased expression further enhance inflammatory signals in HEK 293 cells. 相似文献
110.
During the spring-summer period, vibrios were detected in water and mussels (Mytilus galloprovincialis) collected in 30 sampling sites located in the Mar Piccolo of Taranto (Ionian Sea, Italy). In order to evaluate the degree of microbial pollution of the investigated area, fecal coliforms and Escherichia coli densities were also determined. Vibrio alginolyticus constituted the predominant component of the total culturable vibrios. Some Vibrio species such as V. mediterranei, V. parahaemolyticus, V. diazotrophicus, V. nereis, and V. splendidus were present in water as well as in mussel samples; selective retention in mussels, however, was demonstrated for other vibrios (V. vulnificus, V. cincinnatiensis, V. orientalis, V. anguillarum, V. marinus, V. hollisae). The isolation of some potential pathogenic vibrio species shows the importance of Vibrio research to estimate water quality and to avoid transmission of infection to man and to other marine organisms. 相似文献