Biodegradation of acid red 3BN dye in sequential batch reactor: parameters and kinetics studies

Textile and dye industries generate wastewater which is considered as highly polluted and carcinogenic. Due to this, treatment of wastewater is required earlier to discharge or recycle. In the present studies, treatment of dye bearing water (DBW) has been explored. The treatment was performed using activated sludge (mixed culture) for aerobic process in sequential batch reactor (SBR). The fill volume (V F) and fill time (t F) variation in the treatment of DBW was taken place. The initial value of dye concentration, chemical oxygen demand (COD), sludge, and hydraulic retention time (HRT) were found to play important role in the treatment. At optimum condition (HRT = 2.5 d), the 86.84% COD reduction of 190 mg/L COD, and 92.33% dye reduction of 339 mg/L dye were achieved. These values are equal to overall 94.85% dye reduction of 500 mg/L, and 93.15% COD reduction of 380 mg/L. As a result, 500 mg/L dye was reduced to 26 mg/L, and 380 mg/L COD was reduced to 25 mg/L. The biodegradation fitted to Monod kinetics, for which kinetics parameter values of specific growth rate constant of biomass µ = 0.0047 h−1, yield coefficient (Y) = 1.059, and substrate utilization rate (q) = 0.0044 h−1 were evaluated at HRT = 2.5 d. The results show, this process can be applied to treat Acid Red 3BN Dye Water (AR3BNDW).

Simulation of the incubation time for the formation of (FeB/Fe2B) bilayer on pure iron

In this work, a mathematical model was used in order to study the growth kinetics of (Fe2B/FeB) bilayer during bori-ding process basing on the second Fick’s law and mass balance equation. The run of the numerical simulation allowed calculating the incubation time (τ) of each boronized layer (Fe2B or FeB), and estimating the effect of this parameter on the growth of the boronized layer. The boride incubation time for forming the FeB or Fe2B layer on the pure iron substrate was incorporated into the present mathematical model. To simulate the value of the growth rate constant and the incubation time for the bilayer configuration, the experimental data available in the literature concerning the boronizing of pure iron were considered. Based on the experimental and simulation results, it was shown that the incubation time decreases with increasing temperature in the FeB and Fe2B phases. It was concluded from this study that the thickness of each boride layer depended on its growth rate constant and on another parameter kτ which was the rate constant of incubation time.The obtained results confirmed the validity of the present mathematical model and gave a good estimate of the incubation time during the formation of each boride layer as well as formulated the variation of this parameter with a mathematical equation. Furthermore, the comparison of experimental data with the simulated results of boronized layer thickness allowed to validate the present model.

Modeling Bacterial Regrowth and Trihalomethane Formation in Water Distribution Systems

The formation of bacterial regrowth and disinfection by-products is ubiquitous in chlorinated water distribution systems (WDSs) operated with organic loads. A generic, easy-to-use mechanistic model describing the fundamental processes governing the interrelationship between chlorine, total organic carbon (TOC), and bacteria to analyze the spatiotemporal water quality variations in WDSs was developed using EPANET-MSX. The representation of multispecies reactions was simplified to minimize the interdependent model parameters. The physicochemical/biological processes that cannot be experimentally determined were neglected. The effects of source water characteristics and water residence time on controlling bacterial regrowth and Trihalomethane (THM) formation in two well-tested systems under chlorinated and non-chlorinated conditions were analyzed by applying the model. The results established that a 100% increase in the free chlorine concentration and a 50% reduction in the TOC at the source effectuated a 5.87 log scale decrement in the bacteriological activity at the expense of a 60% increase in THM formation. The sensitivity study showed the impact of the operating conditions and the network characteristics in determining parameter sensitivities to model outputs. The maximum specific growth rate constant for bulk phase bacteria was found to be the most sensitive parameter to the predicted bacterial regrowth.

Predicting overall survival (OS) and overall response (OR) following durvalumab treatment in patients with multiple cancer types using a hybrid modeling strategy.

e15161 Background: This study aimed to predict OS/OR and identify key predictors in patients with diverse cancer types treated with durvalumab, a PD-L1 targeting monoclonal antibody, using a hybrid modeling strategy that combines population pharmacodynamic (PD) modeling and machine learning (ML) algorithms. Methods: Individual longitudinal tumor size measurements and OS/OR data were available for 855 patients who received durvalumab therapy (10 mg/kg Q2W or 20 mg/kg Q4W; NCT01693562). Nine cancer types included non-small cell lung cancer (NSCLC), bladder cancer (BC), microsatellite instability-high (MSI-H) cancer, hepatocellular carcinoma (HCC), squamous cell carcinoma of the head and neck (SCCHN), gastroesophageal cancer (GEC), ovarian cancer (OC), pancreatic adenocarcinoma (PDAC) and triple-negative breast cancer (TNBC). A tumor kinetic model was developed to characterize diverse temporal profiles using a population-based modeling approach. Individual estimated tumor kinetic model parameters and patient demographic/physiological factors were used as inputs for predicting OS/OR using several ML approaches. Results: The final tumor kinetic model with liver metastasis (LM), neutrophil/lymphocyte ratio (NLR), tumor size at baseline (TBSL) and cancer types as covariates characterized the temporal tumor size data well. HCC and MSI-H cancer have the slowest tumor growth rate constant (kg), while GEC, SCCHN and TNBC have the fastest kg. BC, NSCLC and OC have the highest tumor killing rate constant. The most important predictors of OS identified by ML approach were tumor kinetic parameters (kg, fraction of drug-sensitive cells, time-delay in immune response), along with baseline disease factors, including hemoglobin (HGBBL), albumin (ALB), and NLR. Decision tree-based algorithms showed the best performance in predicting OR with accuracy above 90%. In addition to tumor kinetic parameters, PD-L1 expression on tumor cells (TC) and ALB were the most important predictors of OR. Conclusions: A combined population PD/ML approach showed good predictions of OS/OR in patients with different cancer types treated with durvalumab. LM, NLR,TBSL and cancer types were found to be important factors for tumor kinetics. In addition to tumor kinetic parameters, HGBBL, ALB, and NLR were found to be important predictors of OS, and TC and ALB were found to be important predictors of OR. These findings could provide a guidance on patient selection in future clinical trials.

Scaling of statically derived osteocyte lacunae in extant birds: implications for palaeophysiological reconstruction

Osteocytes are mature versions of osteoblasts, bone-forming cells that develop in two ways: via ‘static’ osteogenesis, differentiating and ossifying tissue in situ to form a scaffold upon which other bone can form, or ‘dynamic’ osteogenesis, migrating to infill or lay down bone around neurovasculature. A previous study regressed the volume of osteocyte lacunae derived from dynamic osteogenesis (DO) of a broad sample of extant bird species against body mass, the growth rate constant ( k ), mass-specific metabolic rate, genome size, and erythrocyte size. There were significant relationships with body mass, growth rate, metabolic rate, and genome size, with the latter being the strongest. Using the same avian histological dataset, we measured over 3800 osteocyte lacunar axes derived from static osteogenesis (SO) in order to look for differences in the strength of form–function relationships inferred for DO-derived lacunae at the cellular and tissue levels. The relationship between osteocyte lacunar volume and body mass was stronger when measuring SO lacunae, whereas relationships between osteocyte lacunar volume versus growth rate and basal metabolic rate disappeared. The relationship between osteocyte lacuna volume and genome size remained significant and moderately strong when measuring SO lacunae, whereas osteocyte lacuna volume was still unrelated to erythrocyte size. Our results indicate that growth and metabolic rate signals are contained in avian DO but not SO osteocyte lacunae, suggesting that the former should be used in estimating these parameters in extinct animals.

QUALITATIVE CONCENTRATION OF HUMUS OF CHESTNUT SOILS CONSIDERING MANY-YEAR FERTILIZING

The results of long-term agrochemical experiments highlight quantitative and qualitative changes in the humus status of chestnut soil when applying organic and mineral fertilizers. When fertilizers were not applied, the initial humus concentration in the soil was reduced and on average reached its minimum level of 0.94 ± 0.03% in the 48th year of research. During the whole period in the unfertilized variant, the soil lost 28.3% of the initial amount of humus, or 11.0 t/ha, with an average annual loss of 228 kg. Kinetic parameters of humus reducing in the soil of the control variant reached k = 0.008 year -1 in rapid manifestation. When mineral fertilizers were applied, the humus concentration was higher than in the control variant and reached 1.17 ± 0.05% by the last date of determination. The reduction rate in the variant of applying mineral fertilizer was k = 0.003 year -1. The average annual inflow of root and stubble residues when applying mineral fertilizes compensated humus losses and stabilized its concentration after 30 years of research. Reducing of humus reserves in the soil revealed in a corresponding reduction of annual losses, which reached 131 kg/ha in the first 16 years, with further decrease of 107 kg/ha in 14 years, followed by their absence and slight decrease in the last 7 years - 41 kg/ha. Deficient and positive balance of humus was provided by the variant with manure application. The humus concnetration in the soil for 48 years of applying fertilizers reached 1.50 ± 0.04% and significantly exceeded the initial concentration. On average, during the research period the soil multiplied its reserves on 5.6 t/ha with an average annual growth rate of 117 kg/ha. Kinetics of humus concentration increase in soil in the variant with manure application had a growth rate constant k = 0.002 per year. Ranking of positive quantitative (S gen, %) and qualitative (HC: FC) changes of humus in soil according to estimation variants in dynamics of perennial series occurs in a row: no fertilizers (0.56 % and 0.75) → complete fertilization NPK (0.69 % and 0.79) → manure (0.86 % and 0.92).

Preparation and Characterization of New Liposomes. Bactericidal Activity of Cefepime Encapsulated into Cationic Liposomes

Cefepime is an antibiotic with a broad spectrum of antimicrobial activity. However, this antibiotic has several side effects and a high degradation rate. For this reason, the preparation and characterization of new liposomes that are able to encapsulate this antibiotic seem to be an important research line in the pharmaceutical industry. Anionic and cationic liposomes were prepared and characterized. All cationic structures contained the same cationic surfactant, N,N,N-triethyl-N-(12-naphthoxydodecyl)ammonium. Results showed a better encapsulation-efficiency percentage (EE%) of cefepime in liposomes with phosphatidylcholine and cholesterol than with 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). The presence of cholesterol and the quantity of egg-yolk phospholipid in the liposome increased the encapsulation percentage. The bactericidal activity against Escherichia coli of cefepime loaded into liposomes with phosphatidylcholine was measured. The inhibitory zone in an agar plate for free cefepime was similar to that obtained for loaded cefepime. The growth-rate constant of E. coli culture was also measured in working conditions. The liposome without any antibiotic exerted no influence in such a rate constant. All obtained results suggest that PC:CH:12NBr liposomes are biocompatible nanocarriers of cefepime that can be used in bacterial infections against Escherichia coli with high inhibitory activity.

Evaluation of Single and Joint Toxicity of Perfluorinated Carboxylic Acids and Copper to Metal-Resistant Arthrobacter Strains

Perfluorocarboxylic acid compounds (PFCAs) and copper have been regarded as ubiquitous environmental contaminants in aquatic ecosystems worldwide. However, data on their possible joint toxic effects on microorganisms are still lacking. To study the combined effects of four PFCAs with different carbon chain lengths and copper, a series of experiments were conducted to explore the acute toxicity of these PFCAs in the absence and presence of copper on a metal-resistant Arthrobacter strain GQ-9 by microcalorimetry. The thermokinetic parameters, including growth rate constant (k), inhibitory ratio (I), and half inhibitory concentration (IC50), were calculated and compared using the data obtained from the power-time curves. Our work revealed that GQ-9 is more resistant to perfluorooctanoic acid (PFOA) than Escherichia coli. The single and joint toxicity of PFCAs with copper are dose- and carbon chain length-dependent. The longer the carbon chain length of PFCAs, the higher the toxicity. In addition, PFCAs interacted synergistically with copper. This work could provide useful information for the risk assessment of co-exposure to perfluorinated compounds and heavy metals in natural environments.