A common goal of active packaging is to improve the shelf life, safety, or quality of packaged foods. The integrity of an active package must be remained in order to prevent the growth of microorganisms on the surface of food. Therefore, active polyvinyl alcohol-Alyssum homolocarpum seed gum (PVA-AHSG) composite films with different nisin concentrations (3000, 5000 and 10,000 IU) were prepared and their physico-chemical and antimicrobial properties were determined. Addition of nisin to the composite films increased their water vapor permeability (WVP), elongation at break (EB) and opacity, whereas their total color difference (ΔE), glass transition temperature (Tg), melting temperature (Tm), tensile strength (TS) and young modulus (YM) were decreased. Increasing the nisin concentration remarkably increased the chain mobility, interactions between polymers and water molecules and also the free volume of polymer matrix. The antimicrobial potential of film against L. monocytogene, S. aureus and E. coli as well as the release of nisin into phosphate buffer solution (pH 7.2) were investigated. Films containing nisin had inhibition effect against gram positive pathogens among which L. monocytogenes was the most sensitive bacterium. In liquid media, all films containing nisin prevented the growth of L. monocytogenes and S. aureus, but it was only the film with 10,000 IU nisin content which was able to control 100% of the microbial population during incubation time. Nisin release and diffusion coefficient (D) increased as its concentration increased in the film matrix due to the interaction of nisin with film polymer chains. Therefore, the resultant film had appropriate controlled release property and suitable microbial inhibitory against gram positive bacteria.
Composite bioactive films based on polyvinyl alcohol-Alyssum homolocarpum seed gum blend and Nisin: Physiochemical characterization and antimicrobial properties. Monjazeb et al. (2017).
Background Dendritic cells (DCs) are the most effective antigen-presenting cells. In the last decade, the use of DCs for immunotherapy
of cancer patients has been vastly increased. High endocytic capacity together with a unique capability of initiating primary
T-cell responses have made DCs the most potent candidates for this purpose. Although DC vaccination occasionally leads to
tumor regression, clinical efficacy, and immunogenicity of DCs in clinical trials has not been yet clarified. The present
study evaluated the safety and effectiveness of tumor-lysate loaded DC vaccines in advanced colorectal cancer (CRC) patients
with carcinoembryonic antigen (CEA) positive tumors.
Results Six patients HLA-A*0201-positive were vaccinated with autologous DCs loaded with tumor lysates (TL) together with tetanus
toxoid antigen, hepatitis B, and influenza matrix peptides. Two additional patients were injected with DCs that were generated
from their sibling or parent with one haplotype mismatch. All patients received the vaccines every 2 weeks, with a total of
three intra-nodal injections per patient. The results indicated that DC vaccination was safe and well tolerated by the patients.
Specific immune responses were detected and in some patients, transient stabilization or even reduction of CEA levels were
observed. The injection of haplotype mismatched HLA-A*0201-positive DCs resulted in some enhancement of the anti-tumor response
in vitro and led to stabilization/reduction of CEA levels in the serum, compared to the use of autologous DCs.
Conclusion Altogether, these results suggest that TL-pulsed DCs may be an effective vaccine method in CRC patients. Elimination of regulatory
mechanisms as well as adjustment of the vaccination protocol may improve the efficacy of DC vaccination.
An erratum to this article can be found at 相似文献
Mycoplasma contamination in cell culture is considered as serious problem in the manufacturing of biological products. Our goal in this research is to find the best standard and rapid method with high sensitivity, specificity, accuracy and predictive values of positive and negative results for detection of mycoplasma contamination in cell cultures of the National Cell Bank of Iran. In this study, 40 cell lines suspected to mycoplasma contamination were evaluated by three different methods: microbial culture, enzymatic mycoalert® and molecular. Enzymatic evaluation was performed using the mycoalert® kit while in the molecular technique, a universal primer pair was designed based on the common and fixed 16SrRNA ribosomal sequences used. Mycoplasma contaminations in cell cultures with molecular, enzymatic and microbial culture methods were determined as 57.5, 52.5 and 40 %, respectively. These results confirmed the higher rate of sensitivity, specificity and accuracy for the molecular method in comparison with enzymatic and microbial methods. Polymerase chain reaction (PCR) assay based on fixed and common sequences in the 16SrRNA, is a useful valuable and reliable technique with high sensitivity, specificity and accuracy for detection of mycoplasma contamination in cell cultures and other biological products. The enzymatic mycoalert® method can be considered as a substitution for conventional microbial culture and DNA staining fluorochrome methods due to its higher sensitivity, specificity and speed of detection (<20 min). 相似文献
In this study, we have investigated the plasmon resonance coupling between proximal compositional Al nanoparticles that are organized in a closely spaced molecular orientation as nanoclusters. Plasmon hybridization model is employed as a theoretical model to study the spectral response of the proposed nanostructures. The optical properties of trimer, heptamer, and octamer clusters based on Al/Al2O3 nanodisks are evaluated using finite-difference time-domain (FDTD) model numerically. We have proved that a constructive and weak interference between subradiant dark and superradiant bright modes as the plasmon resonance modes causes the appearance of strong Fano resonances at the spectral response of the heptamer and octamer clusters at the UV spectrum. The effects and results of the structural and chemical modifications in the proposed nanoclusters have been discussed and determined. Finally, illuminating an octamer cluster composed of Al/Al2O3 nanoparticles and simultaneous modifications in the refractive index of the dielectric environment lead to dramatic changes in the position and quality of the Fano dip. Plotting a linear figure of merit (FoM) for the proposed octamer and quantifying this parameter for the structure as 7.72, we have verified that the structure has a strong potential to be used in designing precise localized surface plasmon resonance (LSPR) sensors that are able to sense minor environmental perturbations with high accuracy. Proposed clusters composed of Al/Al2O3 provide an opportunity to design and fabricate low-cost, high responsivity, tunable, and CMOS-compatible devices and efficient biochemical sensors. 相似文献
Livestock depredation by leopards is one of the key conservation issues in landscapes with limited resources worldwide. Any attempts to mitigate human–leopard conflict and conserve the species in conflict should be based on an unequivocal understanding of the conflict patterns. A household survey was conducted with an intention to quantify livestock losses resulting from depredation by leopards in and around the Machiara National Park, Azad Jammu and Kashmir, Pakistan. A total of 301 livestock were killed between June 2007 and August 2008 by leopards. The extent of loss varied in different months, with maximum killing occurring in the month of May. Small-bodied livestock such as goats and sheep were more vulnerable than large-bodied cattle. Goats were killed in significantly higher numbers as compared to other livestock. Domestic animals were killed more frequently at night as compared to other times of the day. There was a significant effect of the nighttime protection measures on depredation. Most attacks happened in valleys and in areas far from the forests. Factors most closely associated with livestock depredation included decline of natural prey, herding practices, guarding especially during the nighttime, and repeated use of pastures where predators were known to be hunting actively. Attitudes of the local community towards leopards were largely negative, and further efforts should be made to improve support for carnivore conservation. We suggest widespread local community education and proactive human–leopard conflict management, particularly through adopting carnivore-friendly livestock protection measures. 相似文献
Rhodium (Rh) has been recently introduced as a perfect metal for ultraviolet (UV) applications with the advantages of its oxide-free nature and support of strong plasmon resonant modes at very short wavelengths. We report on a simple platform of nanoplasmonic structures to support strong plasmonic Fano resonances across the deep-UV spectrum for biochemical sensing applications. We investigate the plasmonic response of several types of Rh nanoparticles and designed dimer-type antennas using nanorings with geometrical tunability in both symmetric and antisymmetric assemblies. Using numerical and theoretical methods, it is shown that Rh-based dimer antennas with broken symmetry can be tailored to support strong plasmon resonant modes at the deep-UV region (\( E>6\; eV \)). We also propose a complex infinity-shaped structure composed of a pair of split rings with a nanodisk in between with extra degree of tunability to push the plasmon resonant modes further in deep-UV spectrum. Plasmon hybridization theory is used to describe formation of plasmonic Fano-resonant dips in simple nanoscale assemblies. We calculate the corresponding figure of merit for the Rh-based nanostructure around 11.5 which shows an excellent sensitivity to the refractive index perturbations of the surrounding medium at very short wavelengths for sensing applications. 相似文献
Most phylogenetic methods assume that the sequences evolved under homogeneous, stationary and reversible conditions. Compositional heterogeneity in data intended for studies of phylogeny suggests that the data did not evolve under these conditions. SeqVis, a Java application for analysis of nucleotide content, reads sequence alignments in several formats and plots the nucleotide content in a tetrahedron. Once plotted, outliers can be identified, thus allowing for decisions on the applicability of the data for phylogenetic analysis. AVAILABILITY: http://www.bio.usyd.edu.au/jermiin/programs.htm. 相似文献