Contribution of the ozonation pre-treatment to the biodegradation of aqueous solutions of 2,4-dichlorophenol

The effect of ozonation on the biodegradability of 100-ppm aqueous solutions of 2,4-dichlorophenol has been investigated. BOD at 5, 10 and 21 days, BOD/COD and BOD/TOC ratios and the average oxidation state are presented. Biodegradability measured as BOD5/COD ratio was increased from 0 of the original solution to 0.25 at the moment of removing all the initial compound (corresponding to an ozone dose of 0.12 g L-1, 0.48 for BOD21/COD ratio). To test the effect of this pre-treatment, the biological oxidation of these pre-ozonated solutions was performed in two semi-continuous stirred tank reactors, one with non-acclimated sludge and one with acclimated-to-phenol sludge. The study showed that the TOC content of the pre-treated solution could be removed up to 68% by an aerobic biological treatment as well as co-digested with municipal wastewater (TOC removal up to 82%), with similar operating retention times to a municipal wastewater plant (12-24 h). Kinetic studies based on Monod model have also been carried out. Pseudo-first-order kinetic constants were found to be in the range of 0.5-0.8 L g TVSS-1 h-1.     

The toxicity of IDPN on the vestibular system of the rat: new insights on its effects on behavior and neurofilament transport

3,3'-Iminodipropionitrile (IDPN) causes a permanent syndrome of abnormalities in spontaneous behavior and a deficit in the axonal transport of neurofilaments (NF). Male Long-Evans rats were given IDPN (0, 200, 400, 600, or 1000 mg/kg, ip, in saline) and assessed for behaviors indicative of vestibular function at 1 week post-dosing. The morphology of the peripheral vestibular system in animals dosed with 0, 200, 400, 600, 800, or 1000 mg/kg of IDPN was assessed at 4 days post-dosing by light microscopy on semithin sections. Animals receiving 1000, 1500, or 2000 mg/kg of IDPN were assessed for morphological alterations in the vestibular ganglion at 8 days post-dosing. Behavioral data indicated a dose-dependent loss of vestibular function after IDPN, the vestibular deficits first appearing at the 400 mg/kg dose level. IDPN exposure was also observed to result in degeneration of the vestibular sensory hair cells. Degenerative changes were already found at the 400 mg/kg dose level, and were extensive after 1000 mg/kg. In the ganglion neurons, no effects were observed after 1000 mg/kg of IDPN, but perikaryal accumulations of NF were found after 1500 or 2000 mg/kg. In conclusion, the data showed that low doses of IDPN are toxic to the vestibular hair cells, and suggest a link between this action and the effects of the chemical on spontaneous behavior. In addition, doses of IDPN larger than those required for toxicity to the vestibular sensory cells, induced accumulations of NF in the myelinated cell bodies of the vestibular ganglion neurons.(ABSTRACT TRUNCATED AT 250 WORDS)     

Adenosine Signaling in Mast Cells and Allergic Diseases

Adenosine is a nucleoside involved in the pathogenesis of allergic diseases. Its effects are mediated through its binding to G protein-coupled receptors: A1, A2a, A2b and A3. The receptors differ in the type of G protein they recruit, in the effect on adenylyl cyclase (AC) activity and the downstream signaling pathway triggered. Adenosine can produce both an enhancement and an inhibition of mast cell degranulation, indicating that adenosine effects on these receptors is controversial and remains to be clarified. Depending on the study model, A1, A2b, and A3 receptors have shown anti- or pro-inflammatory activity. However, most studies reported an anti-inflammatory activity of A2a receptor. The precise knowledge of the adenosine mechanism of action may allow to develop more efficient therapies for allergic diseases by using selective agonist and antagonist against specific receptor subtypes.     

Tau Exon 10 Inclusion by PrPC through Downregulating GSK3β Activity

Tau protein is largely responsible for tauopathies, including Alzheimer’s disease (AD), where it accumulates in the brain as insoluble aggregates. Tau mRNA is regulated by alternative splicing, and inclusion or exclusion of exon 10 gives rise to the 3R and 4R isoforms respectively, whose balance is physiologically regulated. In this sense, one of the several factors that regulate alternative splicing of tau is GSK3β, whose activity is inhibited by the cellular prion protein (PrP^C), which has different physiological functions in neuroprotection and neuronal differentiation. Moreover, a relationship between PrP^C and tau expression levels has been reported during AD evolution. For this reason, in this study we aimed to analyze the role of PrP^C and the implication of GSK3β in the regulation of tau exon 10 alternative splicing. We used AD human samples and mouse models of PrP^C ablation and tau overexpression. In addition, we used primary neuronal cultures to develop functional studies. Our results revealed a paralleled association between PrP^C expression and tau 4R isoforms in all models analyzed. In this sense, reduction or ablation of PrP^C levels induces an increase in tau 3R/4R balance. More relevantly, our data points to GSK3β activity downstream from PrP^C in this phenomenon. Our results indicate that PrP^C plays a role in tau exon 10 inclusion through the inhibitory capacity of GSK3β.     

PolyMAX,a Mobile WiMAX module for the ns-2 simulator with QoS and AMC support

In this paper, we present the PolyMAX module which enhances network simulator 2 (ns-2), the most popular network simulator used in academia, to provide one of the most complete simulation tools to evaluate the performance of Mobile WiMAX networks. PolyMAX is based on the National Institute of Standards and Technology (NIST) module and our specific contributions consist on the design and implementation of the Quality of Service (QoS) classes and QoS management messages, the uplink access grant-request mechanisms, Adaptive Modulation and Coding, and a scheduler handling all five WiMAX QoS classes. We also present validation results for the different components of our module and typical WiMAX simulation scenarios illustrating its flexibility and some of its features. The PolyMAX module represents an important tool enabling researchers to easily implement their Mobile WiMAX scheduling and Adaptive Modulation and Coding (AMC) algorithms and accurately evaluate their performance for realistic scenarios.     

The joint Gateway Placement and Spatial Reuse Problem in Wireless Mesh Networks

A Wireless Mesh Network (WMN) is composed of multiple Access Points (APs) that are connected together using the radio channel and by a limited number of gateway APs connected to the Internet. In this paper, we address the problem of gateway placement that consists of minimizing the number of gateways while satisfying system performance requirements. Along with the placement problem, the formulation includes joint routing and scheduling to account for the problem of interference and to enable spacial reuse. The problem, which we coined GPSRP (Gateway Placement and Spatial Reuse Problem), allows a much more efficient use of the available resources and reduces overall gateway costs. This article presents for the first time a mathematical formulation of the problem and discusses its advantages and limitations with respect to other approaches.     

Analysis of the HLA class I associated peptide repertoire in a hepatocellular carcinoma cell line reveals tumor-specific peptides as putative targets for immunotherapy

HLA class I molecules present peptides on the cell surface to CD8(+) T cells. The repertoire of peptides that associate to class I molecules represents the cellular proteome. Therefore, cells expressing different proteomes could generate different class I-associated peptide repertoires. A large number of peptides have been sequenced from HLA class I alleles, mostly from lymphoid cells. On the other hand, T cell immunotherapy is a goal in the fight against cancer, but the identification of T cell epitopes is a laborious task. Proteomic techniques allow the definition of putative T cell epitopes by the identification of HLA natural ligands in tumor cells. In this study, we have compared the HLA class I-associated peptide repertoire from the hepatocellular carcinoma (HCC) cell line SK-Hep-1 with that previously described from lymphoid cells. The analysis of the peptide pool confirmed that, as expected, the peptides from SK-Hep-1 derive from proteins localized in the same compartments as in lymphoid cells. Within this pool, we have identified 12 HLA class I peptides derived from HCC-related proteins. This confirms that tumor cell lines could be a good source of tumor associated antigens to be used, together with MS, to define putative epitopes for cytotoxic T cells from cancer patients.     

Segmentation of multiple sclerosis lesions in brain MRI: A review of automated approaches

Automatic segmentation of multiple sclerosis (MS) lesions in brain MRI has been widely investigated in recent years with the goal of helping MS diagnosis and patient follow-up. However, the performance of most of the algorithms still falls far below expert expectations. In this paper, we review the main approaches to automated MS lesion segmentation. The main features of the segmentation algorithms are analysed and the most recent important techniques are classified into different strategies according to their main principle, pointing out their strengths and weaknesses and suggesting new research directions. A qualitative and quantitative comparison of the results of the approaches analysed is also presented. Finally, possible future approaches to MS lesion segmentation are discussed.     

Crack tip identification with long FBG sensors in mixed-mode delamination

The uncertainty of the crack tip position inside composite coupons during a delamination test under variable fracture mode conditions reduces the accuracy of the experimental results. In this work a method is presented where the crack tip position is located using long embedded Fibre Bragg Grating (FBG) sensors together with the Optical Low Coherence Reflectometry (OLCR) technique. With this technique the local Bragg wavelength is measured which then enables to calculate the axial strain profile within the grating. Carbon/epoxy samples are tested under different mode ratios through the standard Mixed-Mode Bending (MMB) test. Embedded long FBG sensors are used to measure the axial strain profile along the whole grating at different stages of the test. The crack tip can be precisely identified with the long embedded FBGs and then checked by means of a visual inspection after complete delamination of the sample. The data indicate that the long FBG sensor detects the crack tip inside the sample at least as precisely as the traditionally performed visual inspections carried out during the test by means of the lateral markings. Numerical simulations using cohesive elements are in good agreement with the experimental data.