Évolution des acides aminés et de la matière organique dissoute dans une filière de production d'eau potable: Corrélations avec le carbone organique dissous biodégradable et le potentiel de demande en chlore à long terme

Le suivi de la matière organique totale (COD) et spécifique (substances humiques et principalement acides aminés dissous totaux) dans les eaux d'une filière de production d'eau potable a mis en évidence des abattements moyens dans l'eau traitée représentant 40 % du COD et 0 à 75 % des acides aminés. Parallèlement, le potentiel de demande en chlore à long terme est diminué de près de 70 %, alors que la fraction biodégradable connait une élimination de l'ordre de 50 %.Aucune corrélation directe n'a pu être mise en évidence entre les teneurs en acides aminés et la valeur du carbone organique dissous biodégradable (CODB) et de la demande en chlore des eaux brutes ou en cours de traitement. Cependant, compte tenu des teneurs en acides aminés dissous totaux quantifiées dans les eaux traitées de l'usine, leur participation peut être estimée entre 5 et 23 % du potentiel de demande en chlore et entre 5 et 25 % du CODB.La matière organique analysée spécifiquement dans le cadre de cette étude (substances humiques et acides aminés dissous totaux), représente 20 à 35 % du COD des eaux en fin de filière, et la présence de ces composés organiques serait responsable d'une part notable de la demande en chlore à long terme des eaux (40 à 60 %).Dissolved organic compounds (dissolved organic carbon (DOC), biodegradable dissolved organic carbon (BDOC), total amino acids and humic substances) and their chlorine demand were analyzed monthly at different steps of the water treatment plant of Méry-sur-Oise (Paris, France, 270 000 m3/d, Fig. 1).Total dissolved amino acids were determined by HPLC analysis with fluorimetric detection after hydrolysis of combined amino acids (proteins, polypeptides) by hydrochloric acid (DOSSIER BERNE et al., 1994 a); the separation of 17 amino acids was performed after orthophthaldialdehyde (OPA) pre-column derivatization. Humic substances were determined according to the method developed by THURMAN and MALCOLM (1981), by gravity feeding XAD-8 resins with acidified samples. The humic fraction was expressed as the difference between DOC before and after passage through the column. The method developped by JORET and LÉVI (1986) using a biologically active sand inoculum was used for the determination of BDOC.For the determination of chlorine consumption, the kinetic model described by JADAS- HÉCART et al. (1992) was used; it takes into account the long-term chlorine demand in terms of potential demand. This method was automated (DOSSIER BERNE et al., 1994 b) and computer-assisted. The chlorine dose was chosen depending on the DOC value and on the N-NH4+ content of the water; the applied dose was: 3 mg Cl2/mg DOC + 10 mg Cl2/mg N-NH4+. Chlorine determination was performed automatically by the spectrophotometric N, N-diethylphenylene-1,4-diamine (DPD) method.In raw water, DOC values may reach 5.6 to 6.5 mg C l-¹ during the cold season, but the average yield of elimination was generally close to 40 % (Fig. 2). The biodegradable fraction of the organic carbon (BDOC), which represents 25 to 50 % of the DOC in the raw water, was partially removed in the plant and the residual concentration in treated water varied between 0.4 to 1.8 mg C l-¹ (Fig. 2). A transitory increase in the BDOC values was generally observed during the ozonation step; it reached 0.2 to 0.5 mg C l-¹ (Figs. 6 and 7).Whatever the period of the year, extracted humic substances constituted about 50 % of the DOC found in raw water (Fig. 3). This hydrophobic fraction was significantly removed in the treatment plant reducing the proportion of humic substances in the DOC of treated water to 16 - 23 % (Figs. 3, 6 and 7). The concentrations of total dissolved amino acids ranged from 100 to 260 µg l-¹ C in raw water and from 50 to 150 µg l-¹ C in produced water (Fig. 4); the main part of this elimination occurred during the clarification step (Figs. 6 and 7). No important seasonal variations could be observed for chlorine demand (Fig. 5); its removal occurred at each step of treatment and the average global elimination by the plant was of the order of 70 % (Figs. 6 and 7).On account of the low concentrations of amino acids, no direct relation could be shown between amino acid concentrations and the respective values of BDOC or of chlorine demand potential (Figs. 9 and 10). With regards to BDOC and chlorine demand potential, no correlation could be shown between these two parameters either (Fig. 8). However, it was possible to calculate the contribution of specific classes of dissolved organic compounds to chlorine demand and to BDOC. This calculation is based: i) on the concentrations of humic substances and amino acids measured during the monthly experiments at each point of the treatment plant, ii) on bibliographic data concerning the contribution to BDOC (biodegradability) and chlorine consumption of a large variety of model molecules (free or combined amino acids, aquatic humic substances). The results obtained in this way are reported in Table 3 for the treated water of the M?ry sur Oise plant. These results indicate that the small amounts of total dissolved amino acids present in treated water may account for 5 to 25 % of the BDOC value and for 5 to 23 % of the total chlorine demand potential. With regard to humic substances, their biodegradability was assumed to be very low but their contribution to the chlorine demand of the treated water was estimated between 10 to 40 %, whereas their DOC contribution ranges from 16 to 35 %. As a consequence, both amino acids and humic substances could account for 40 to 60 % to the chlorine demand of treated water. A special point should be noticed for total amino acids: their contribution to the DOC values of treated water was only 2 to 7 %, but they may account for a larger proportion of BDOC or chlorine demand potential (5 to 25 %)

Instrumental and perceptual evaluation of dereverberation techniques based on robust acoustic multichannel equalization

Speech signals recorded in an enclosed space by microphones at a distance from the speaker are often corrupted by reverberation, which arises from the superposition of many delayed and attenuated copies of the source signal. Because reverberation degrades the signal, removing reverberation would enhance quality. Dereverberation techniques based on acoustic multichannel equalization are known to be sensitive to room impulse response perturbations. In order to increase robustness, several methods have been proposed, as for example, using a shorter reshaping filter length, incorporating regularization, or applying a sparsity-promoting penalty function. This paper focuses on evaluating the performance of these methods for single-source multi-microphone scenarios, using instrumental performance measures as well as using subjective listening tests. By analyzing the correlation between the instrumental and the perceptual results, it is shown that signal-based performance measures are more advantageous than channel-based performance measures to evaluate the perceptual speech quality of signals that were dereverberated by equalization techniques. Furthermore, this analysis also demonstrates the need to develop more reliable instrumental performance measures

Measuring, modelling and predicting perceived reverberation

This paper investigates the relationship between the perceived level of reverberation and parameters measured from the room impulse response (RIR), as well as the design of an instrumental measure that predicts this perceived level. We first present the results of an experimental listening test conducted to assess the level of perceived reverberation in speech captured by a single microphone, before analysing the gathered data to assess the influence of parameters such as the reverberation time (T60) or the direct-to-reverberant ratio (DRR). Secondly, we use the results of this analysis to improve the signal based reverberation decay tail (RDT) measure, previously proposed by the authors to predict the perceived level of reverberation. The accuracy of the proposed measure is evaluated in terms of correlation with the subjective scores and compared to the performance of predictors using parameters extracted from the RIR. Results show that the proposed modifications to the RDT does improve its accuracy. Though still slightly outperformed by measures based on parameters of the RIR, we believe the proposed measure to be useful in scenarios in which the RIR or its parameters are unknown

Non-intrusive speech quality prediction using modulation energies and LSTM-network

Many signal processing algorithms have been proposed to improve the quality of speech recorded in the presence of noise and reverberation. Perceptual measures, i.e., listening tests, are usually considered the most reliable way to evaluate the quality of speech processed by such algorithms but are costly and time-consuming. Consequently, speech enhancement algorithms are often evaluated using signal-based measures, which can be either intrusive or non-intrusive. As the computation of intrusive measures requires a reference signal, only non-intrusive measures can be used in applications for which the clean speech signal is not available. However, many existing non-intrusive measures correlate poorly with the perceived speech quality, particularly when applied over a wide range of algorithms or acoustic conditions. In this paper, we propose a novel non-intrusive measure of the quality of processed speech that combines modulation energy features and a recurrent neural network using long short-term memory cells. We collected a dataset of perceptually evaluated signals representing several acoustic conditions and algorithms and used this dataset to train and evaluate the proposed measure. Results show that the proposed measure yields higher correlation with perceptual speech quality than that of benchmark intrusive and non-intrusive measures when considering various categories of algorithms. Although the proposed measure is sensitive to mismatch between training and testing, results show that it is a useful approach to evaluate specific algorithms over a wide range of acoustic conditions and may, thus, become particularly useful for real-time selection of speech enhancement algorithm settings

Smooth-muscle-associated contractile protein in renal mesenchymal tumour cells and in transformed cells from DMN-injected rats.

Cryostat sections and established in vitro cultures of dimethylnitrosamine(DMN)-induced renal mesenchymal tumours and monolayer cultures of transformed kidney cells derived from rats treated with a carcinogenic dose of DMN were examined by indirect immunofluorescence with human serum containing smooth muscle antibody. Eight mesenchymal tumours examined showed filamentous cytoplasmic staining of spindle cells infiltrating between renal tubules, whilst in normal kidneys interstitial cells were only weakly positive. In established in vitro cultures from 6 mesenchymal tumours, different patterns of staining were observed in morphologically different cell forms, ranging from fine filamentous staining in giant cells to diffuse cytoplasmic fluorescence in small bipolar cells, and cell outline staining in polygonal cells. In addition filamentous staining of microvillous projections and nucleolar staining were observed in some tumour cells. Monolayer cultures of transformed kidney cells showed strong staining of coarse, randomly-orientated cytoplasmic filaments, whilst fibroblasts cultured from normal rat kidney demonstrated an ordered array of fine, parallel filaments. Specificity of the immunofluorescent staining reaction was established by failure to obtain staining with normal serum, with smooth muscle antibody serum neutralized by homogenates of smooth muscle or extracts containing actin derived from smooth muscle. These results indicate that there is an apparent increase of actin-like contractile microfilaments in transformed cells and in renal mesenchymal tumours. The cytoplasmic contracile microfilaments in these cells may play a role in tumour cell mobility and invasion

TCF7L2 variant genotypes and type 2 diabetes risk in Brazil: significant association, but not a significant tool for risk stratification in the general population

<p>Abstract</p> <p>Background</p> <p>Genetic polymorphisms of the <it>TCF7L2 </it>gene are strongly associated with large increments in type 2 diabetes risk in different populations worldwide. In this study, we aimed to confirm the effect of the <it>TCF7L2 </it>polymorphism <it>rs7903146 </it>on diabetes risk in a Brazilian population and to assess the use of this genetic marker in improving diabetes risk prediction in the general population.</p> <p>Methods</p> <p>We genotyped the single nucleotide polymorphisms (SNP) rs7903146 of the <it>TCF7L2 </it>gene in 560 patients with known coronary disease enrolled in the MASS II (Medicine, Angioplasty, or Surgery Study) Trial and in 1,449 residents of Vitoria, in Southeast Brazil. The associations of this gene variant to diabetes risk and metabolic characteristics in these two different populations were analyzed. To access the potential benefit of using this marker for diabetes risk prediction in the general population we analyzed the impact of this genetic variant on a validated diabetes risk prediction tool based on clinical characteristics developed for the Brazilian general population.</p> <p>Results</p> <p>SNP rs7903146 of the <it>TCF7L2 </it>gene was significantly associated with type 2 diabetes in the MASS-II population (OR = 1.57 per T allele, p = 0.0032), confirming, in the Brazilian population, previous reports of the literature. Addition of this polymorphism to an established clinical risk prediction score did not increased model accuracy (both area under ROC curve equal to 0.776).</p> <p>Conclusion</p> <p><it>TCF7L2 </it>rs7903146 T allele is associated with a 1.57 increased risk for type 2 diabetes in a Brazilian cohort of patients with known coronary heart disease. However, the inclusion of this polymorphism in a risk prediction tool developed for the general population resulted in no improvement of performance. This is the first study, to our knowledge, that has confirmed this recent association in a South American population and adds to the great consistency of this finding in studies around the world. Finally, confirming the biological association of a genetic marker does not guarantee improvement on already established screening tools based solely on demographic variables.</p

Impact of COVID-19 pandemic on eye cancer care in United Kingdom

The COVID-19 pandemic has had an unprecedented impact on the National Health Service in United Kingdom. The UK Ocular Oncology Services evaluated the impact on the adult eye cancer care in the UK. All four adult Ocular Oncology centres participated in a multicentre retrospective review comparing uveal melanoma referral patterns and treatments in a 4-month period during the national lockdown and first wave of the COVID-19 pandemic in 2020 with corresponding periods in previous 2 years. During the national lockdown, referral numbers and confirmed uveal melanoma cases reduced considerably, equalling to ~120 fewer diagnosed uveal melanoma cases compared to previous 2 years. Contrary to the recent trend, increased caseloads of enucleation and stereotactic radiosurgery (p > 0.05), in comparison to fewer proton beam therapy (p < 0.05), were performed. In the 4-month period following lockdown, there was a surge in clinical activities with more advanced diseases (p < 0.05) presenting to the services. As the COVID-19 pandemic continues to mount pressure and reveal its hidden impact on the eye cancer care, it is imperative for the Ocular Oncology Services to plan recovery strategies and innovative ways of working

Predicting Diabetes: Clinical, Biological, and Genetic Approaches: Data from the Epidemiological Study on the Insulin Resistance Syndrome (DESIR)

OBJECTIVE—To provide a simple clinical diabetes risk score and to identify characteristics that predict later diabetes using variables available in the clinic setting as well as biological variables and polymorphisms

No association between a candidate TCF7L2 variant and risk of breast or ovarian cancer

<p>Abstract</p> <p>Background</p> <p>TCF7L2 is a transcription factor involved in Wnt/β-catenin signaling which has a variant known to be associated with risk of Type 2 diabetes and, in some studies, with risk of certain cancers, including familial breast cancer. No studies of ovarian cancer have been reported to date.</p> <p>Methods</p> <p>Two clinic-based case-control studies at the Mayo Clinic were assessed including 798 breast cancer cases, 843 breast cancer controls, 391 ovarian cancer cases, and 458 ovarian cancer controls. Genotyping at <it>TCF7L2 </it>rs12255372 used a 5' endonuclease assay, and statistical analysis used logistic regression among participants as a whole and among <it>a priori</it>-defined subsets.</p> <p>Results</p> <p>No associations with risk of breast or ovarian cancer were observed (ordinal model, p = 0.62 and p = 0.75, respectively). In addition, no associations were observed among sub-groups defined by age, BMI, family history, stage, grade, histology, or tumor behavior.</p> <p>Conclusion</p> <p>Although the biology of the Wnt/β-catenin signaling pathway and prior association between rs12255372 and numerous phenotypes warranted examination of this <it>TCF7L2 </it>SNP, no compelling evidence for association with breast or ovarian cancer was observed.</p