Enzymatic hydrophobic modification of jute fibers via grafting to reinforce composites

Horseradish peroxidase (HRP)/H2O2 system catalyzes the free-radical polymerization of aromatic compounds such as lignins and gallate esters. In this work, dodecyl gallate (DG) was grafted onto the surfaces of lignin-rich jute fabrics by HRP-mediated oxidative polymerization with an aim to enhance the hydrophobicity of the fibers. The DG-grafted jute fibers and reaction products of their model compounds were characterized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results clearly indicated the grafting of DG to the jute fiber by HRP. Furthermore, the hydrophobicity of jute fabrics was determined by measuring the wetting time and static contact angle. Compared to the control sample, the wetting time and static contact angle of the grated fabrics changed from ~1 s to 1 h and from ~0° to 123.68°, respectively. This clearly proved that the hydrophobicity of jute fabrics improved considerably. Conditions of the HRP-catalyzed DG-grafting reactions were optimized in terms of the DG content of modified jute fabrics. Moreover, the results of breaking strength and elongation of DG-grafted jute/ polypropylene (PP) composites demonstrated improved reinforcement of the composite due to enzymatic hydrophobic modification of jute fibers.This work was financially supported by the National Natural Science Foundation of China (51173071), the Program for New Century Excellent Talents in University (NCET-12-0883), Program for Changjiang Scholars and Innovative Research Team in University (No. IRT_15R26) the Fundamental Research Funds for the Central Universities (JUSRP51312B, JUSRP51505), and the Graduate Student Innovation Plan of Jiangsu Province of China (SJLX_0527)

Влияние фосфатных связующих на физико-механические свойства периклазохромитовых огнеупоров

У данній статті наведено та порівняно фізико-механічні властивості периклазо-хромітових матеріалів в залежності від різних типів фосфатних зв’язуючих та введення різних домішок. Визначено, що найбільш раціональним є введення триполіфосфату натрію.In given clause are resulted and the physycal-mechanical properties periclase-cgromite of materials are compared depending on different of types phosphate binding and introduction of the various additives. Is determined, that most rational is the introduction treepolyphosphate sodume

Potential biological role of poly (ADP-ribose) polymerase (PARP) in male gametes

Maintaining the integrity of sperm DNA is vital to reproduction and male fertility. Sperm contain a number of molecules and pathways for the repair of base excision, base mismatches and DNA strand breaks. The presence of Poly (ADP-ribose) polymerase (PARP), a DNA repair enzyme, and its homologues has recently been shown in male germ cells, specifically during stage VII of spermatogenesis. High PARP expression has been reported in mature spermatozoa and in proven fertile men. Whenever there are strand breaks in sperm DNA due to oxidative stress, chromatin remodeling or cell death, PARP is activated. However, the cleavage of PARP by caspase-3 inactivates it and inhibits PARP's DNA-repairing abilities. Therefore, cleaved PARP (cPARP) may be considered a marker of apoptosis. The presence of higher levels of cPARP in sperm of infertile men adds a new proof for the correlation between apoptosis and male infertility. This review describes the possible biological significance of PARP in mammalian cells with the focus on male reproduction. The review elaborates on the role played by PARP during spermatogenesis, sperm maturation in ejaculated spermatozoa and the potential role of PARP as new marker of sperm damage. PARP could provide new strategies to preserve fertility in cancer patients subjected to genotoxic stresses and may be a key to better male reproductive health

Sampling and sample preparation for analysis of aromas and fragrances

Some recent advances in sampling and sample-preparation technologies for fragrance analysis are addressed in this review. Procedures, such as analytical distillation (vapor distillation and simultaneous distillation-extraction), headspace-manipulation methods (static and dynamic headspace analysis and headspace solid-phase microextraction) and direct extraction. methods (such as liquid-liquid, solid-phase and supercritical fluid), will be-discussed and critically evaluated. Contemporary applications of these techniques to the study of natural and synthetic aromas Will be presented. (C) 2003 Published by Elsevier Science B.V.22316016

Diuina quaedam S. Ephraem opera / e graeca lingua versa Petro Francisco Zino, interprete.

Marca tip. en port.ColofónEnc. Perg.Sign.: A-L8, M

Analysis of the volatile compounds of Brazilian chilli peppers (Capsicum spp.) at two stages of maturity by solid phase micro-extraction and gas chromatography-mass spectrometry

The volatile fractions of three varieties of chilli peppers at two stages of maturity were characterised using headspace solid phase micro-extraction (HS-SPME), gas chromatography (GC-FID) and mass spectrometry (GC-MS). A total of 83 compounds, mostly esters and alcohols, were identified in the malagueta chilli pepper (Capsicum frutescens), 49 compounds, mostly monoterpenes and aldehydes, were identified in the dedo-de-moca chilli pepper (Capsicum baccatum var. pendulum) and 77 compounds, mostly esters and sesquiterpenes, were identified in the murupi chilli pepper (Capsicum chinense). The peak areas of the compounds were smaller in the more mature samples. The samples from C. baccatum var. pendulum exhibited the greatest decrease; most of the compounds were not detected in the more mature samples. (C) 2012 Elsevier Ltd. All rights reserved.4819810

SPME applied to the study of volatile organic compounds emitted by three species of Eucalyptus in situ

Headspace solid-phase microextraction coupled to gas chromatography/ion trap mass spectrometry-65 mum polydimethylsiloxane/divinylbenzene (PDMS/DVB) was used to identify and monitor the emission patterns of biogenic volatile organic compounds from leaves of Eucalyptus dunnii, Eucalyptus saligna, and Eucalyptus citriodora in situ. Short extractions (1 min) were performed every 30 min for periods of 8-10 h during 24 days taking advantage of the high capacity of this porous polymer coating. Forty-two compounds were detected and 20 identified in the headspace of E saligna leaves, and 19 of 27 compounds were identified in the headspace of E dunnii leaves. The emission pattern of (E)-beta-ocimene and rose oxide suggests that they may play a bioactive role in Eucalyptus.50257199720

Monitoring biogenic volatile compounds emitted by Eucalyptus citriodora using SPME

A procedure to monitor BVOC emitted by living plants using SPME technique is presented. For this purpose, a glass sampling chamber was designed. This device was employed for the characterization of biogenic volatile compounds emitted by leaves of Eucalyptus citriodora. After extraction with SPME fibers coated wi th PDMS/ DVB, it was possible to identify or detect 33 compounds emitted by this plant. A semiquantitative approach was applied to monitor the behavior of the emitted BVOC during 9 days. Circadian profiles of the variation in the concentration of isoprene were plotted. Using diffusion-based SPME quantitation, a recently introduced analytical approach, with extraction times as short as 15 s, it was possible to quantify subparts-per-billion amounts of isoprene emitted by this plant.73194729473