Study of the performance of disinfection with sodium hypochlorite on a full-scale sewage treatment plant

A full-scale sewage treatment plant was investigated to assess the performance of the disinfection stage. Sodium hypochlorite was used as a disinfectant agent and the process efficiency was evaluated by E.coli removal. The research took place over a period of two years in order to evaluate the effect of retention time (t) and residual chlorine (Cr) under different seasonal conditions. The effectiveness of E.coli removal with sodium hypochlorite proved to be strictly dependent on the factor CR t (product of residual chlorine with the contact time). The regression line of the experimental points was, on the whole, well comparable with the model proposed by Collins, especially in the field of CRt lower than 30 mg L-1 min

IEC 61508: Effect of test policy on the probability of failure on demand of safety instrumented systems

Standard IEC 61508 provides probabilistic equations for determining the Average Probability of Failure on Demand (PFDavg) and the Average Probability of Failure per Hour (PFHavg) for some architectures of Safety Instrumented Systems (SIS) under the hypothesis of equal redundant components, taking into account Common Cause Failures (CCF), Detection Coverage (DC) and Proof Test Coverage (PTC) parameters. Surprisingly, IEC standard does not mention the testing policy aspects of SIS redundant components. However, from a close examination of the probabilistic equations, it is possible to recognize that the simultaneous/sequential testing policy has been implicitly assumed. This paper describes the conditions under which the staggered testing policy - which is better than all the others in case of independent tested components - can be advantageously applied to reduce PFDavg when CCF, DC and PTC parameters are taken into account

Aeraulic behaviour of a biotrickling filter pilot plant: experiments and simulations

Trickling bed biofilters (or biotrickling filters, BTFs) are biological systems for polluted air treatment. Hydrodynamics of BTFs, and reactors in general, is of paramount importance for obtaining good performances. In fact, a non-uniform distribution of the pollutant into the bed brings to dead zones or bypass which reduce the bed working volume and, therefore, cause low removal efficiencies. The paper presents the preliminary results obtained regarding the aeraulic behavior of a BTF pilot plant with seashells as packing material. Experimental results of bed void fraction and pressure drop at several flow rates were used to obtain Ergun equation coefficients for dry bed. A numerical simulation of the reactor flow field carried out with a commercial CFD (Computational Fluid Dynamics) code, validated by the means of velocity measurements made with a Hot Wire Anemometer (HWA) completed the analysis of the reactor hydrodynamics

A Key Silencing Histone Mark on Chromatin Is Lost When Colorectal Adenocarcinoma Cells Are Depleted of Methionine by Methionine γ-Lyase

Methionine is an essential amino acid used, beyond protein synthesis, for polyamine formation and DNA/RNA/protein methylation. Cancer cells require particularly high methionine supply for their homeostasis. A successful approach for decreasing methionine concentration is based on the systemic delivery of methionine γ-lyase (MGL), with in vitro and in vivo studies demonstrating its efficacy in cancer therapy. However, the mechanisms explaining how cancer cells suffer from the absence of methionine more significantly than non-malignant cells are still unclear. We analyzed the outcome of the human colorectal adenocarcinoma cancer cell line HT29 to the exposure of MGL for up to 72 h by monitoring cell viability, proteome expression, histone post-translational modifications, and presence of spurious transcription. The rationale of this study was to verify whether reduced methionine supply would affect chromatin decondensation by changing the levels of histone methylation and therefore increasing genomic instability. MGL treatment showed a time-dependent cytotoxic effect on HT29 cancer cells, with an IC50 of 30 µg/ml, while Hs27 normal cells were less affected, with an IC50 of >460 µg/ml. Although the levels of total histone methylation were not altered, a loss of the silencing histone mark H3K9me2 was observed, as well as a decrease in H4K20me3. Since H3K9me2/3 decorate repetitive DNA elements, we proved by qRT-PCR that MGL treatment leads to an increased expression of major satellite units. Our data indicate that selected histone methylation marks may play major roles in the mechanism of methionine starvation in cancer cells, proving that MGL treatment directly impacts chromatin homeostasis

Improving biotreatment efficiency of hot waste air streams: experimental upgrade of a full plant

Biological methods as bio and biotrickling filtration are an energy-efficient and economical alternative to treat biodegradable odorants and volatile organic compounds (VOCs) in order to obey stringent releases regulations that have arisen during the last few decades. In this work a plant upgrade case study, employing these techniques, is presented. It refers to a critical situation in which off air streams, characterized by medium odorous compounds loads and high temperatures, were treated using a biofilter only. In that context, sufficient removal efficiencies were not achieved. Therefore, it has been proposed to replace the existing biofilter by a biotrickling one implementing a minimal number of structural plant modifications

Salicylic Acid Peel Incorporating Triethyl Citrate and Ethyl Linoleate in the Treatment of Moderate Acne: A New Therapeutic Approach.

BACKGROUND: Acne affects many adolescents. Conventional therapy often results in side effects and poor adherence, and the treatment does not consider the psychological effect of acne on patients, which is comparable with that of disabling diseases. OBJECTIVES: To evaluate the efficacy and tolerability of a peel (30% salicylic acid, triethyl citrate and ethyl linoleate) combined with a home therapy with three topical agents (triethyl citrate, ethyl linoleate and salicylic acid 0.5% cream, lotion) in moderate acne of the face. DESIGN: Prospective, observational, multicenter, open-label, postmarketing, phase IV study. METHODS: Patients were assessed by comparing Global Acne Grading System (GAGS) score and total lesion count from 15 days before the first peel (T-15 ), after four salicylic peels (every 10 ± 2 days (T0 , T10 , T20 , T30 ), and 20 days after of the end of the study (T50 ). This treatment was associated to a home therapy. RESULTS: Fifty-three patients completed the study. The average GAGS score fell 49% between T-15 and T50 (p < .001). No patient withdrew for adverse events. CONCLUSIONS: This therapy was effective and well-tolerated in all cases. Chemo-exfoliation sessions ensured the continuous monitoring of clinical results and improved patient quality of life

Application of strategies for particulate matter reduction in urban areas: an italian case

The paper describes the particulate matter pollution in a Northern Italian city: Varese. The city is distinguished by a particular orographic and meteorological situation, characterized by valleys and heavy rainfalls. Nevertheless the urban area is interested by particulate matter pollution mainly due to heating systems and traffic. Here some corrective strategies in order to reduce PM air pollution have been presented, applied and evaluated by the means of a simplified model which considers emissions and meteorological conditions

Phylogeographic Analysis of HIV-1 Subtype C Dissemination in Southern Brazil

The HIV-1 subtype C has spread efficiently in the southern states of Brazil (Rio Grande do Sul, Santa Catarina and Paraná). Phylogeographic studies indicate that the subtype C epidemic in southern Brazil was initiated by the introduction of a single founder virus population at some time point between 1960 and 1980, but little is known about the spatial dynamics of viral spread. A total of 135 Brazilian HIV-1 subtype C pol sequences collected from 1992 to 2009 at the three southern state capitals (Porto Alegre, Florianópolis and Curitiba) were analyzed. Maximum-likelihood and Bayesian methods were used to explore the degree of phylogenetic mixing of subtype C sequences from different cities and to reconstruct the geographical pattern of viral spread in this country region. Phylogeographic analyses supported the monophyletic origin of the HIV-1 subtype C clade circulating in southern Brazil and placed the root of that clade in Curitiba (Paraná state). This analysis further suggested that Florianópolis (Santa Catarina state) is an important staging post in the subtype C dissemination displaying high viral migration rates from and to the other cities, while viral flux between Curitiba and Porto Alegre (Rio Grande do Sul state) is very low. We found a positive correlation (r2 = 0.64) between routine travel and viral migration rates among localities. Despite the intense viral movement, phylogenetic intermixing of subtype C sequences from different Brazilian cities is lower than expected by chance. Notably, a high proportion (67%) of subtype C sequences from Porto Alegre branched within a single local monophyletic sub-cluster. These results suggest that the HIV-1 subtype C epidemic in southern Brazil has been shaped by both frequent viral migration among states and in situ dissemination of local clades