Growth Rate Kinetics Research Articles

Machine learning approach for microbial growth kinetics analysis of acetic acid-producing bacteria isolated from organic waste

This study proposes novel hybrid methodology that combines machine learning (ML) techniques with experimental strategies to analyse microbial growth-kinetics of acetic acid-producing bacteria isolated from fruit waste. This work employs ML algorithms to create different models such as multivariate linear regression (MLR), partial least square regression (PLSR), Kernel ridge regression (KRR), support vector regression (SVR), Gradient boosting regression (GBR) that captures time-dependent patterns of bacterial growth dynamics. Experiments for microbial growth kinetic analysis were conducted on best isolate of acid producing bacteria with different glucose concentrations (1–5 %) at predefined operating conditions. It is found significant growth rate (µ) was obtained at 4 % and 5 % concentration of glucose from experimental work. 0.0588 h−1 and 0.0571 h−1 are the specific growth rate obtained at 4 % and 5 % glucose concentration respectively. Proposed ML models employed to predict growth rate kinetics theoretically at varied glucose concentrations. Comparative results indicate that GBR model exhibits superior performance in predicting growth kinetics than other models. GBR model fits the experimental results approximately with lower RMSE (0.004) than other models. This enables more accurate representation of growth patterns that is difficult to discernible through conventional analytical methods. This approach will help to understand growth kinetics of acetic acid-producing bacteria for resource recovery, wastewater treatment, and bioremediation.

Thermal cycling performance assessment of double-layered lanthanum titanium aluminate thermal barrier coatings developed using plasma spheroidized powders

In this present investigation, lanthanum titanium aluminate (LTA) powder is prepared by solid-state sintering followed by spheroidization through an atmospheric plasma spray torch within a spheroidization chamber. The spheroidized powder is used to deposit thermal barrier coatings (TBCs). The developed coatings were evaluated for thermal cycling performance at 1150 °C, and the phase and microstructural observations were carried out before and after thermal cycling. A continuous layer of alumina (Al2O3) thermally grown oxide (TGO) is grown at the interface of the NiCoCrAlY bond coat and YSZ top coat in both coatings. The higher TGO growth rate kinetics beyond the critical thickness-induced thermal stresses and the associated coefficient of thermal expansion (CTE) mismatch between the TGO and the top coat resulted in the delamination of the coatings.

Hyperprogressive disease during atezolizumab plus bevacizumab treatment in patients with advanced hepatocellular carcinoma from Japanese real-world practice

BackgroundHyperprogressive disease (HPD) is a phenomenon with greatly accelerated tumor growth and clinical deterioration rates compared to pre-therapy, in patients treated with immune checkpoint inhibitors (ICI). The aim of this study is to clarify the reality of HPD in patients with advanced hepatocellular carcinoma (HCC) who were treated with atezolizumab plus bevacizumab (Atez/Bev) using tumor dynamics.MethodsMedical records of consecutive patients with advanced HCC who were treated with Atez/Bev were retrospectively reviewed. HPD was defined as a more than two- or fourfold increase in tumor growth rate (TGR) or tumor growth kinetics rate (TGKR) before and after treatment. Overall survival (OS) and baseline characteristics with or without HPD were analyzed.ResultsA total of 85 patients were included in the analysis. When HPD was defined as a twofold of TGR or TGKR, 8 patients (8/85, 9.4%) had HPD and 11 had PD without HPD. A total of 5 patients (5/85, 5.9%) were diagnosed with HPD and 14 with PD without HPD when HPD was defined as a fourfold of TGR or TGKR. No significant difference was observed in the baseline characteristics between HPD and non-HPD.ConclusionThe prevalence of HPD in patients with advanced HCC treated with Atez/Bev was lower than those treated with nivolumab monotherapy. The HPD mechanism in ICI combined with antibodies targeting vascular endothelial growth factor (VEGF) remains to be elucidated.

Microbial Growth Rate Kinetics in Biogas Production by Anaerobic Digestion of Chicken Manure

Kinetic study of microorganism’s growth in chicken manure (CM) when producing biogas is often studied for scale-up purposes. CM are considered as waste, and can cause serious environmental consequences when not properly disposed. The objective of the study is to know the characteristics of the bioreactor condition or environment responsible for CM degradation and biogas production. Methods involves serial dilution, pour plating, cell count and the determination of Monod parameters. POLYMATH regression results shows that CM of particle density 0.0163 g/cm3 gives a maximum specific growth rate, ?_max of 0.007316 hr^(-1) and half saturation constant, K_s of 3.8×?10?^8mg/l which points to substrate sufficiency for the survival of microorganisms and biogas production.

2D Liquid-Crystallization-Driven Self-Assembly of Rod-Coil Block Copolymers: Living Growth and Self-Similarity.

Liquid-crystallization-driven self-assembly (LCDSA) is an emerging methodology, which has been employed to construct controllable 1D nanostructures. However, 2D nanostructures via living LCDSA are rarely reported, and the complicated growth kinetics are not well-known. Herein, we perform Brownian dynamics (BD) simulations to investigate the 2D living growth of disklike micelles via LCDSA of rod-coil block copolymers. The 2D seeded-growth behavior is achieved by incorporating the unimers onto the edges of disklike seeds with smectic-like liquid-crystalline (LC) cores. The fluidity of such LC-like micellar cores is conducive to the chain adjustments of rod blocks during the 2D living growth process. The apparent growth rate and unique self-similarity kinetics are governed by the interplay between the variations in the growth rate coefficient and the reactive sites at the micelle edges. This work provides an in-depth understanding of the 2D living growth of micelles and guidance to construct well-defined 2D hierarchical nanostructures.

Raman analysis of octocoral carbonate ion structural disorder along a natural depth gradient, Kona coast, Hawai‘i

Abstract Both environmental and physiological factors cause carbonate ion structural disorder in biogenic Mg-calcites. A major component of this disorder is driven by the incorporation of Mg through environmental forcing and growth rate kinetics although non-Mg factors (e.g., other cation/anion impurities, organic molecules) also contribute. Understanding the drivers of Mg content in biogenic calcite and its effects on disorder has implications for octocoral Mg paleo-proxies and the stability and diagenetic alteration of their calcitic skeletons. However, prior studies of biogenic Mg-calcites have often been complicated by sampling inconsistencies over space and time and potential intra-sample Mg variability. This study aims to analyze the relative contributing factors of octocoral Mg-calcite structural disorder along gradients of both depth and growth rate. Calcitic octocorals (Coralliidae and Keratoisididae, N = 28) were collected from 221–823 m depths across a natural gradient in biogeochemical parameters (pH: 7.4–7.9, T: 5–16 °C) off the Kona coast of Hawai‘i Island and were analyzed using Raman spectroscopy. Samples were collected during the same month, controlling for potential seasonal variability. Raman spectral parameters from the ν1 peak quantified total carbonate ion structural disorder (full-width at half maximum height [FWHM] of ν1) and Mg content (ν1 position, Raman shift). The total structural disorder was then partitioned into Mg-driven and non-Mg driven components (residual ν1 FWHM). The total structural disorder and Mg content decreased significantly with increasing depth, correlating with temperature and carbonate system parameters. The Mg-temperature relationships from this study were also consistent with prior studies. Non-Mg structural disorder did not correlate to any environmental parameters. When measured across an intra-sample gradient of ontogenetic growth rate, total structural disorder, Mg content, and non-Mg structural disorder increased with growth rate for all but one taxon, demonstrating the kinetic effect of growth rate as well as potential taxon-specific physiological effects. These results provide insight into how environmental and growth rate kinetic effects independently affect different components of carbonate ion structural disorder (Mg content and non-Mg factors). These findings also suggest that Raman spectroscopy may be helpful in quantifying solubility within biogenic calcites.

Plant Growth-Promoting Rhizobium Nepotum Phenol Utilization: Characterization and Kinetics

Phenol is a severe pollutant that harms the environment and, potentially, human health. This study aimed to investigate the biodegradability of phenol by the plant growth-promoting bacterium R. nepotum. That included studying the growth kinetics and the effects of growth conditions such as incubation temperature, pH, and the use of different substrate concentrations. As the primary substrate, six different starting concentrations of phenol were utilized. The ability of these cells to biodegrade phenol was greatly influenced by the culture conditions. After 36 and 96 hours of incubation at pH 7 and a temperature of 28 C, this organism grew the fastest and had the highest phenol biodegradation. The biodegradation rate is much higher at 700 mg/L, the highest of the six concentrations tried. In less than 96 hours of incubation, more than 90% of the phenol (700 mg/L) had been eliminated. The Haldane model has been the most accurate for determining the relationship between the initial concentration of phenol and growth rate. In contrast, the refined Gompertz model provided the most accurate depiction of phenol biodegradation over time. As predicted by the Haldane equation, the highest specific growth rate, half-saturation coefficient, and Haldane's growth kinetics inhibition coefficient are 0.7161 h1, 15.8 parts per million (ppm), and 292 parts per million (ppm), respectively. The equation of Haldane successfully fitted the experimental data by reducing the SSR (sum of squared errors) to 3.8x10 3. According to the results of the analysis by GC-MS for the bacterial culture sample, the hydroxylase enzyme was the first to convert the phenol molecule into catechol. The catechol was subsequently broken down into 2-hydroxymucconic semialdehyde by the 2,3-dioxygenase enzyme, which occurred through the meta-pathway. It is the first study showing that R. nepotum, a plant growth promoter, has high efficiency of phenol. In phenol-stressed conditions, this could help with rhizoremediation and crop yield preservation.

Assessing the validity and sensitivity of microbial processes within a hydrodynamic model

Eutrophication due to excess anthropogenic nutrients in waterways is a significant issue worldwide. The pressure-stressor-response of a waterway to excessive nutrient loading is reliant on numerous physical and biological factors, including hydrodynamics and microbial processing. While substantial progress has been made towards simulating these mechanisms there are limited multi-disciplinary studies that relate the physical hydrodynamics of a site with the ecological response from linked laboratory and field studies. This paper presents the development of a coupled hydrodynamic and aquatic ecosystem response model, expanded to include an integrated microbial loop, that allows the explicit representation of heterotrophic bacteria growth and dissolved organic nutrient mineralisation. A unique long-term water quality dataset at an estuary in south-eastern Australia was used to validate and assess the model's sensitivity to complex biophysical processes driving the observed water quality variability. Results indicate that explicit time-varying bacterial mineralisation rates provide a substantially improved understanding of the broader aquatic ecosystem response than assigned fixed bulk rate parameter values, which are typically derived from non-local literature. Implementation of a microbial loop at the study site indicated that the model is sensitive to the boundary conditions, in particular catchment loads, with both net transport rates and the net growth rates of heterotrophic bacteria demonstrating different responses. Under average flow conditions, a smaller net transport and reduced nutrient availability has a pronounced effect of lowering net growth rates through the applied limitation factors. During high flow conditions, freshwater inflows increased net transport and nutrient loads, which resulted in higher net growth rates. Further, temporal variability in water temperature had a compounding effect on the model's response sensitivity. This approach has broader application in other riverine systems subject to eutrophication, and in interrogating linkages in hydrodynamic and microbial mediated processes (e.g., productivity). Future studies are recommended to better understand the sensitivity of aquatic ecosystem response models to microbial net growth rate kinetics at different temperatures and from top-down predation (e.g., zooplankton grazing).

Hyperprogression under immunotherapy: a new form of immunotherapy response?-a narrative literature review.

ObjectiveUpdate the last known review, and summarize the definitions, diagnostic criteria, reported risk factors, possible mechanisms and potential biomarkers of hyperprogressive disease (HPD) under immunotherapy.BackgroundImmunotherapy is a relatively new systemic therapy adding a new method of treatment of especially advanced cancer patients. In a variety of immunotherapies, however, an unexpected acceleration of tumor growth, known as HPD, is observed in approximately 30% of patients after immune checkpoint inhibitor (ICI) treatment. HPD has a deleterious survival effect on patients and represents an urgent issue for both clinicians and patients. Existing literature has reviewed and summarized the definition, diagnostic criteria, reported risk factors and possible mechanisms of hyperprogression. However, with the gradual deepening of the exploration of HPD, researchers have made significant breakthroughs in elucidating the mechanism and mechanism of HPD and exploring biomarkers.MethodsThe search was conducted on Google Scholar and PubMed in January and May of 2021. We searched among English papers with no limitation on the publication year. We have included retrospective studies, case reports and basic researches related to HPD in the collection, we also referred to some review articles on HPD in recent years. A qualitative-interpretive approach was used for data extraction.ConclusionsHPD is considered to be an acceleration of tumor growth after ICI treatment that is not only due to immune infiltration but also due to real disease progression, with an incidence of about 4–30% in all retrospective published studies to date. Currently, the most widely used criteria of HPD contain Response Evaluation Criteria in Solid Tumors (RECIST) and tumor growth rate (TGR) or tumor growth kinetics. The common risk factors and underlying mechanisms of HPD have not yet been fully elucidated. However, based on the poor prognosis of HPD, there have been many advances in the exploration of biomarkers in recent years, like the prediction of HPD, such as LDH levels of peripheral blood, liquid biopsy, and radiomics, etc.

Fusicoccin (FC)-Induced Rapid Growth, Proton Extrusion and Membrane Potential Changes in Maize (Zea mays L.) Coleoptile Cells: Comparison to Auxin Responses

The fungal toxin fusicoccin (FC) induces rapid cell elongation, proton extrusion and plasma membrane hyperpolarization in maize coleoptile cells. Here, these three parameters were simultaneously measured using non-abraded and non-peeled segments with the incubation medium having access to their lumen. The dose–response curve for the FC-induced growth was sigmoidal shaped with the maximum at 10−6 M over 10 h. The amplitudes of the rapid growth and proton extrusion were significantly higher for FC than those for indole-3-acetic acid (IAA). The differences between the membrane potential changes that were observed in the presence of FC and IAA relate to the permanent membrane hyperpolarization for FC and transient hyperpolarization for IAA. It was also found that the lag times of the rapid growth, proton extrusion and membrane hyperpolarization were shorter for FC compared to IAA. At 30 °C, the biphasic kinetics of the IAA-induced growth rate could be changed into a monophasic (parabolic) one, which is characteristic for FC-induced rapid growth. It has been suggested that the rates of the initial phase of the FC- and IAA-induced growth involve two common mechanisms that consist of the proton pumps and potassium channels whose contribution to the action of both effectors on the rapid growth is different.

Deep learning-based oriented object detection for in situ image monitoring and analysis: A process analytical technology (PAT) application for taurine crystallization

Image analysis enables the estimation of critical process properties such as crystal size, morphology, and crystallization kinetics. Despite the rich image information, the lack of a robust image analysis technique has been an obstacle to promote its applications. In this work, an automated image analysis technique that combines the state-of-the-art oriented object detection model, S2A-Net, was developed for in situ estimation of the two-dimensional crystal size distribution (CSD) and the crystal counts. The model was trained to detect and classify both crystals and clusters to enable quantification of the extent of agglomeration and exclude unreliable detections. The effectiveness and robustness of extracting size and aspect ratio at various image complexities were verified by comparing with the focused beam reflective measurement (FBRM) and manually analyzed images in the experimental studies for taurine batch cooling crystallization with different seed loadings. An on-line calibration strategy for solute concentration measurement with Raman spectroscopy was introduced to eliminate the dedicated calibration experiments. The secondary nucleation and growth rate kinetics were evaluated from the on-line measurements and validated by numerical simulation. The proposed method provides a novel PAT strategy that enables accurate two-dimensional size measurement and shape characterization for online monitoring and control of a solution crystallization process.

Definition, Incidence, and Challenges for Assessment of Hyperprogressive Disease During Cancer Treatment With Immune Checkpoint Inhibitors

Hyperprogressive disease (HPD) is a recognized pattern of rapid tumor progression during immune checkpoint inhibitor (ICI) treatment. Definitions of HPD have not been standardized, posing the risk of capturing different tumoral behaviors. To provide a systematic summary of definitions and the incidence of HPD in patients undergoing ICI treatment and discuss the challenges of current assessment of HPD. Articles that evaluated HPD published before March 3, 2020, were identified from MEDLINE and EMBASE. Clinical trials and observational studies providing the incidence and definition of HPD from patients with cancer treated with ICIs. Factors included in the analysis comprised authors, year of publication, cancer type, ICI type, number of previous treatment lines, definition of HPD, time frame used to assess HPD, number of patients with HPD, onset of HPD, and prognosis of patients with HPD. Quantitative and qualitative syntheses for the incidence of HPD were performed. Definitions of HPD were categorized and the range of incidence of HPD was evaluated. Subgroup analysis on the incidence of HPD according to the category was performed and the challenges associated with current HPD assessment were evaluated. Twenty-four studies with 3109 patients were analyzed. The incidence of HPD varied from 5.9% to 43.1%. The definitions were divided into 4 categories based on the calculation of tumor growth acceleration: tumor growth rate ratio (pooled incidence of HPD, 9.4%; 95% CI, 6.9%-12.0%), tumor growth kinetics ratio (pooled incidence, 15.8%; 95% CI, 8.0%-23.7%), early tumor burden increase (pooled incidence, 20.6%; 95% CI, 9.3%-31.8%), and combinations of the above (pooled incidence, 12.4%; 95% CI, 7.3%-17.5%). Hyperprogressive disease could be overestimated or underestimated if the assessment was limited to tumor growth rate or tumor growth kinetics ratio, target lesions, or response evaluation criteria in solid tumors (RECIST)-defined progressors, or if the assessment time frame conformed to RECIST. Study results on clinical outcome were heterogeneous on discriminating patients with HPD from those with natural progressive disease. Definitions of HPD appear to be diverse, with the incidence of HPD varying from 5.9% to 43.1% across studies examined in this meta-analysis. Varying incidence and definitions of HPD indicate the need for establishing its uniform and clinically relevant criteria based on currently available evidence.

Clarification of Definitions of Hyperprogressive Disease During Immunotherapy for Non–Small Cell Lung Cancer

Hyperprogressive disease (HPD) is an aggressive pattern of progression reported for patients treated with programmed cell death 1 (PD-1)/programmed cell death 1 ligand (PD-L1) inhibitors as a single agent in several studies. However, the use of different definitions of HPD introduces the risk of describing different tumoral behaviors. To assess the accuracy of each HPD definition to identify the frequency of HPD and the association with poorer outcomes of immune-checkpoint inhibitor (ICI) treatment in patients with advanced non-small cell lung cancer (NSCLC) and to provide an optimized and homogenized definition based on all previous criteria for identifying HPD. This retrospective cohort study included 406 patients with advanced NSCLC treated with PD-1/PD-L1 inhibitors from November 1, 2012, to April 5, 2017, in 8 French institutions. Measurable lesions were defined using the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria on at least 2 computed tomographic scans before the initiation of ICI therapy and 1 computed tomographic scan during treatment. Data were analyzed from November 1, 2012, to August 1, 2019. Advanced NSCLC and treatment with PD-1/PD-L1 inhibitors. Association of the definition with the related incidence and the HPD subset constitution and the association between each HPD definition and overall survival. All dynamic indexes used in the previous proposed definitions, such as the tumor growth rate (TGR) or tumor growth kinetics (TGK), were calculated before and during treatment. Among the 406 patients with NSCLC included in the analysis (259 male [63.8%]; median age at start of ICI treatment, 64 [range, 30-91] years), the different definitions resulted in incidences of the HPD phenomenon varying from 5.4% (n = 22; definition based on a progression pace >2-fold and a time to treatment failure of <2 months) to 18.5% (n = 75; definition based on the TGR ratio). The concordance between these different definitions (using the Jaccard similarity index) varied from 33.3% to 69.3%. For every definition, HPD was associated with poorer survival (range of median overall survival, 3.4 [95% CI, 1.9-8.4] to 6.0 [95% CI, 3.7-9.4] months). The difference between TGR before and during therapy (ΔTGR) was the most correlated with poor overall survival with an initial plateau for a larger number of patients and a slower increase, and it had the highest ability to distinguish patients with HPD from those with progressive disease not classified as HPD. In addition, an optimal threshold of ΔTGR of greater than 100 was identified for this distinction. The findings of this retrospective cohort study of patients with NSCLC suggest that the previous 5 definitions of HPD were not associated with the same tumor behavior. A new definition, based on ΔTGR of greater than 100, appeared to be associated with the characteristics expected with HPD (increase of the tumor kinetics and poor survival). Additional studies on larger groups of patients are necessary to confirm the accuracy and validate this proposed definition.

Effect of Free Hydroxylamine on the Activity of Two Typical Nitrite-oxidizing Bacteria

The sludge from enrichment of Nitrobacter and Nitrospira was used as a research object and batch tests were performed. The inhibitory effects of hydroxylamine on Nitrobacter and Nitrospira under the same pH and different hydroxylamine concentration gradients, the same hydroxylamine concentration, and different pH gradients were investigated. The results showed that under the same pH condition, the activity of Nitrobacter decreased with increasing hydroxylamine concentration. Under the same hydroxylamine concentration (HA=5 mg·L-1) at a higher pH environment (pH ≥ 7.5), hydroxylamine produced more free hydroxylamine (FHA) and the inhibitory effect on Nitrobacter was improved. At a low pH environment (pH≤7), ionic hydroxylamine promoted the activity of Nitrobacter. The inhibitory effect of hydroxylamine on Nitrospira was limited. When pH=7.5 and hydroxylamine concentration was 45 mg·L-1, the relative activity of Nitrospira was 82%. The NOB growth rate kinetics model and the non-substrate inhibition linear equation were used to describe the effect of FHA on Nitrobacter and Nitrospira activity. The coefficient of determination R2 was 0.90 and 0.94, respectively. FHA may be the main reason for inhibiting the activity of Nitrobacter and Nitrospira.

Hyperprogressive Disease upon Immune Checkpoint Blockade: Focus on Non-small Cell Lung Cancer.

Describe the controversial aspects of hyperprogressive disease (HPD) definition, mechanisms, and biomarkers. Although immune checkpoint inhibitors (ICIs) demonstrated a survival benefit in non-small cell lung cancer (NSCLC), an acceleration of tumor growth during ICI, defined as HPD, was reported in ~ 13-26% of NSCLC patients and correlated with worse survival compared with conventional progression. Different criteria have been used for HPD definition. The main limitation for the use of tumor growth rate and tumor growth kinetics variations is its inapplicability for patients without a pre-baseline imaging or progressing on non-measurable lesions. On the contrary, time to treatment failure and clinical criteria (i.e., worsening of performance status, presence of new lesions, or metastatic spread to different sites) can be useful in the above-mentioned settings but do not consent an assessment of tumor growth before ICI initiation. Several mechanisms of HPD have been proposed so far, involving both adaptive and innate immunity or based on cell-autonomous signals of cancer growth triggered by ICI. The characterization of HPD biomarkers and the identification and validation on large series of one or more mechanistic explanations for the HPD phenomenon are of paramount significance to avoid detrimental immunotherapy in a subgroup of patients and exploit novel therapeutic targets for future immunotherapy combinations. HPD occur in a subgroup of NSCLC patients treated with ICI. Several definitions and mechanisms have been proposed and a consensus on HPD criteria and biological bases is currently lacking.

Identification of novel hypoxia-responsive factors in deep-water rice conferring tolerance to flood during germination

Flood in rice fields at the time of seed sowing and early seedling establishment causes extensive crop loss due to the inability of the seeds to tolerate and overcome submergence. In the present study, rice genotypes from Assam, India tolerant to hypoxia during germination were identified through systematic screening of deep-water rice genotype collection from flood-prone ecosystem of Brahmaputra river valley. The difference in tolerance to hypoxia during germination within the species provides scope for identification of novel hypoxia-responsive factors involved in tolerance as mechanism of tolerance may not be conserved across tolerant germplasms. Tolerant genotypes were further subjected to physiological and molecular characterization. Growth rate kinetics in tolerant genotypes new Rangdhakekua bao (RKB) and cultivar Khao Hlan On (KHO) from International Rice Research Institute (IRRI) used as positive control exhibited stronger escape strategy under hypoxic condition compared to sensitive genotype IR-64 (negative control). Activities of &#945;-amylase and pyruvate decarboxylase were significantly higher in RKB and KHO than in IR-64, while no significant difference was observed in the alcohol dehydrogenase activity. Reverse transcription quantitative PCR confirmed increased amounts of transcripts of sucrose nonfermenting 1 related protein kinase, myeloblastosis-related protein S1, rice amylase 3D, and trehalose phosphate phosphatase 7 genes, which are known to be involved in hypoxia signaling cascade. Besides, transcription factors (TFs) like ethylene responce factors 71 and 63, ethylene insensitive 3-like 1a and proteins like expansins A7 and A2, which are involved in cell elongation had also significantly higher amounts in RKB compared to IR-64. Additional factors that include TFs like ERF71 and ERF63 that shows perturbation at transcription even within tolerant genotypes might constitute the genotype-specific regulation, evolved as a part of its adaptive mechanism to survive under submerged conditions.

Co-simulation of CFD-multiphase population balance coupled model aeration of sludge flocs in stirrer tank bioreactor

Aerated stirrer tank bioreactors are commonly used to convert organics and remove nutrients through microbial floc environments. Computational Fluid Dynamic CFD based on multiphase approach coupled with gas (air) and solid (sludge flocs) population balance models (pbm) are using in co-simulation to modelling dynamics complex multiphysics phenomena in different time scales. Co-simulation coupled CFD-PBM-kinetic models to captured the biomass growth kinetics and the influence of the reactor hydrodynamics on the overall process. Floc size distribution is crucial as it determines distinct grades of final floc structures, which are to be used as commercial aerobic wastewater treatment respectively. The coupled population balance equation was solved using an inhomogeneous discrete method of the continuous partial differential equation for sludge flocs and standard methods of moments for gas phase, which were then solved simultaneously and influence on biomass kinetics growth. Additionally, the influence of the agitator's speed and air flow rate on dynamic biomass growth have been investigated in full transient CFD analysis. The kinetics of biomass growth rate, as a function of oxygen saturation and air/flocs population balance was employed in the model through User Defined Function (UDF). The integrated modelling multiphysics in a multiphase system methodology by co-simulation represents a valuable tool to examine the impact of individual parameters of the biomass growth in the bioreactor.

Assessment of the body development kinetic of broiler breeders by non-invasive imaging tools

In order to determine the body composition of parental broilers during growth from hatching to adulthood (32 wk of age), we evaluated the kinetics of fattening, growth rate, reproduction parameters, and body composition of the animals by using non-invasive tools such as medical imaging (ultrasound and CT scan) and blood sample analysis. The use of CT scanner allowed us to monitor the development of the body composition (fatness, bone, muscle, ovary, and testis growth) of these same animals. These analyses were accompanied by biochemical blood analyses such as steroids, metabolites, and some adipokines concentration. Difference in the body composition between males and females appeared at 16 wk of age. From 20 wk of age, shortly before the onset of lay, the females had 1.6-fold more adipose tissues than males (P < 0.001) and 8-fold more elevated plasma triglycerides levels. In addition, females, from 16 wk of age, presented a weakened bone quality in comparison to males (P < 0.001). The ratio of the tibia volume/tibia length was 33.2% lower in female compared to male chicken at 32 wk of age (P < 0.001). However, the pectoral muscle had the same volume in both sexes. The production of steroids by gonad started at 16 wk of age for both sexes, and the testis and ovary development could be measured by imaging tools at 24 wk. The follicle development was correlated to the ovarian fat tissue (r = 0.80) and fatness. In conclusion, the use of CT scanner and ultrasound system has allowed investigate the body composition of live animals and actual parental breeds with to the aim of using them for genetic selection.

On the performance of electrocoagulation-assisted biological treatment processes: a review on the state of the art

The combined treatment systems have become a potential alternative to treat highly polluted industrial wastewater to achieve high-quality treated effluents. The current review focuses on the treatment systems compromising electrocoagulation (EC) as a pretreatment step followed by a biological treatment step. The reasons for applying EC as a pretreatment process were mainly to (1) detoxify the wastewater by removing inhibitors of the biotreatment step or (2) to remove the major part of the COD or (3) the dissolved materials that could cause fouling to membrane bioreactors or (4) to increase the activity of the microorganisms. This combination represents a new and promising application characterized by higher performance and removal efficiency. The main published findings related to this application are presented and analyzed. Besides, the statistical models used to optimize the process variables and the kinetics of microorganism growth rate are discussed herein. Most of the previous investigations were conducted in a laboratory-scale level with biologically treated water as a feed to the EC process. Only a few works applied a hybrid system consisting of the biological step and the EC step. In all studies, improved performance and higher removal efficiencies of the combined process were achieved particularly when applying aluminum electrodes, providing more than 95% removal efficiency. Many researchers have reported that they had faced a significant problem in the operation of the electrocoagulation process associated with the reduction of electrodes' efficiency caused by deposits of the coagulation complex. This problem needs to be effectively resolved.

The short- and long-term inhibitory effects of Fe (II) on anaerobic ammonium oxidizing (anammox) process.

The application of the anammox process has great potential in treating nitrogen-rich wastewater. The presence of Fe (II) is expected to affect the growth and activity of anammox bacteria. Short-term (acute) and long-term effects (chronic) of Fe (II) on anammox activity were investigated. In the short-term study, results demonstrated that the optimum concentration of Fe (II) that could be added to anammox is 0.08 mM, at which specific anammox activity (SAA) improved by 60% compared to the control assay, 0.00 mM. The inhibition concentration, IC50, of Fe (II) was found to be 0.192 mM. Kinetics of anammox specific growth rate were estimated based on results of the batch test and evaluated with Han-Levenspiel's substrate inhibition kinetics model. The optimum concentration and IC50 of Fe (II) predicted by the Han-Levenspiel model was similar to the batch test, with values of 0.07 mM and 0.20 mM, respectively. The long-term effect of Fe (II) on the performance of a sequencing batch reactor (SBR) was evaluated. Results showed that an appropriate Fe (II) addition enhanced anammox activity, achieving 85% NH4 +-N and 96% NO2 --N removal efficiency when 0.08 mM of Fe (II) was added. Quantitative polymerase chain reaction (qPCR) was adopted to detect and identify the anammox bacteria.