Inference for the maximum cell probability under multinomial sampling

AbstractWe implemented machine learning in the radiation biodosimetry field to quantitatively reconstruct neutron doses in mixed neutron + photon exposures, which are expected in improvised nuclear device detonations. Such individualized reconstructions are crucial for triage and treatment because neutrons are more biologically damaging than photons. We used a high-throughput micronucleus assay with automated scanning/imaging on lymphocytes from human blood ex-vivo irradiated with 44 different combinations of 0–4 Gy neutrons and 0–15 Gy photons (542 blood samples), which include reanalysis of past experiments. We developed several metrics that describe micronuclei/cell probability distributions in binucleated cells, and used them as predictors in random forest (RF) and XGboost machine learning analyses to reconstruct the neutron dose in each sample. The probability of “overfitting” was minimized by training both algorithms with repeated cross-validation on a randomly-selected subset of the data, and measuring performance on the rest. RF achieved the best performance. Mean R2 for actual vs. reconstructed neutron doses over 300 random training/testing splits was 0.869 (range 0.761 to 0.919) and root mean squared error was 0.239 (0.195 to 0.351) Gy. These results demonstrate the promising potential of machine learning to reconstruct the neutron dose component in clinically-relevant complex radiation exposure scenarios.

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Production of Newcastle Disease Virus by Vero Cells Grown on Cytodex 1 Microcarriers in a 2-Litre Stirred Tank Bioreactor

Journal of Biomedicine and Biotechnology ◽

10.1155/2010/586363 ◽

2010 ◽

Vol 2010 ◽

pp. 1-7 ◽

Cited By ~ 15

Author(s):

Mohd Azmir Arifin ◽

Maizirwan Mel ◽

Mohamed Ismail Abdul Karim ◽

Aini Ideris

Keyword(s):

Cell Culture ◽

Newcastle Disease Virus ◽

Disease Virus ◽

Newcastle Disease ◽

High Speed ◽

Virus Titer ◽

Vero Cells ◽

Stirred Tank ◽

Stirred Tank Bioreactor ◽

Maximum Cell

The aim of this study is to prepare a model for the production of Newcastle disease virus (NDV) lentogenic F strain using cell culture in bioreactor for live attenuated vaccine preparation. In this study, firstly we investigated the growth of Vero cells in several culture media. The maximum cell number was yielded by culture of Vero cells in Dulbecco's Modified Eagle Medium (DMEM) which was1.93×106 cells/ml. Secondly Vero cells were grown in two-litre stirred tank bioreactor by using several commercial microcarriers. We achieved the maximum cell concentration about7.95×105 cells/ml when using Cytodex 1. Later we produced Newcastle Disease virus in stirred tank bioreactor based on the design developed using Taguchi L4 method. Results reveal that higher multiplicity of infection (MOI) and size of cell inoculums can yield higher virus titer. Finally, virus samples were purified using high-speed centrifugation based on3∗∗(3-1) Fractional Factorial Design. Statistical analysis showed that the maximum virus titer can be achieved at virus sample concentration of 58.45% (v/v), centrifugation speed of 13729 rpm, and centrifugation time of 4 hours. As a conclusion, high yield of virus titer could be achieved through optimization of cell culture in bioreactor and separation by high-speed centrifugation.

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Use of design of experiments to optimize the production of microbial probiotic biofilms

PeerJ ◽

10.7717/peerj.4826 ◽

2018 ◽

Vol 6 ◽

pp. e4826 ◽

Cited By ~ 3

Author(s):

Barbara Speranza ◽

Arcangelo Liso ◽

Maria Rosaria Corbo

Keyword(s):

Design Of Experiments ◽

Growth Phase ◽

Lactobacillus Reuteri ◽

Model Organism ◽

Cellular Growth ◽

Effects Of Ph ◽

Probiotic Strains ◽

Maximum Cell ◽

Short Time ◽

Control Samples

Here, we describe the production of a probiotic biofilm through three intermediate steps: (1) measurement of the adhesion capacity of 15 probiotic strains to evaluate their tendency to form biofilm on different surfaces (stainless steel, glass, and polycarbonate); (2) evaluation of the effects of pH, temperature, cellular growth phase, agitation, and presence of surfactants on probiotic biofilm formation (BF) through the Design of Experiments (DoE) approach; (3) study of the effects of pH, temperature and surfactants concentration on probiotic BF using the Central Composite Design. Finally, we show that biofilms pre-formed by selected probiotics can delay the growth of pathogens, such asListeria monocytogeneschosen as model organism. Among the tested strains,Bifidobacterium infantisDSM20088 andLactobacillus reuteriDSM20016 were found to be as the probiotics able to ensure the greatest adhesion (over 6 Log CFU cm2) to the surfaces tested in a very short time (<24 h). Cellular growth phase and agitation of the medium were factors not affecting BF, pH exerted a very bland effect and a greater tendency to adhesion was observed when the temperature was about 30 °C. The results obtained in the last experimental phase suggest that our probiotic biofilms can be used as an efficient mean to delay the growth ofL. monocytogenes: the λ phase length, in fact, was longer in samples containing probiotic biofilms (0.30–1.02 h) against 0.08 h observed in the control samples. A reduction of the maximum cell load was also observed (6.99–7.06 Log CFU mL−1against about 8 Log CFU mL−1observed in the control samples).

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Growth of human diploid cells (strain MRC-5) in defined medium; replacement of serum by a fraction of serum ultrafiltrate

Journal of Cell Science ◽

10.1242/jcs.35.1.381 ◽

1979 ◽

Vol 35 (1) ◽

pp. 381-392

Author(s):

K. Lambert ◽

S.J. Pirt

Keyword(s):

Amino Acids ◽

Active Material ◽

Maximum Yield ◽

Calf Serum ◽

Defined Medium ◽

Cell Yield ◽

Maximum Cell ◽

Macromolecular Component ◽

Human Diploid Cells ◽

Diploid Cells

A calf serum ultrafiltrate fraction permitted growth for at least 3.5 generations, including one subculture, of MRC-5 cells in defined medium in the absence of whole serum. The active material has a molecular weight of 10 000 Daltons or less. This suggests that there may be no requirement for a large macromolecular component of serum. The ultrafiltrate was assayed by maximum cell yield from a serum-limited inoculum in a defined medium containing non-limiting amounts of vitamins, amino acids, glucose, a 68-component supplement, iron and methylcellulose. The levels of vitamins, amino acids and glucose were based on quantitative measurements of uptake and the levels of the other components by minimum amount required for maximum yield in defined medium without ultrafiltrate or serum. With excess ultrafiltrate maximum cell yield was limited by the defined part of the medium, probably the supplement. The cell doubling time in defined medium with ultrafiltrate fractions was 70 h compared with 27 h in the medium with serum. Excess ultrafiltrate did not inhibit growth. The lowered growth rate is attributed to a nutritional deficiency in the supplement.

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The Glucose, Insulin and Glutamine Requirements of Suspension Cultures of HeLa Cells in a Difined Culture Medium

Journal of Cell Science ◽

10.1242/jcs.9.2.529 ◽

1971 ◽

Vol 9 (2) ◽

pp. 529-537

Author(s):

G. J. BLAKER ◽

J. R. BIRCH ◽

S. J. PIRT

Keyword(s):

Amino Acid ◽

Hela Cells ◽

Growth Yield ◽

Dry Weight ◽

Defined Medium ◽

Cell Populations ◽

Serum Supplement ◽

Protamine Sulphate ◽

Protamine Zinc Insulin ◽

Maximum Cell

The serum supplement in a defined medium for the growth of HeLa cells could be replaced by protamine-zinc-insulin (0.2 u./ml). Insulin (0.4 u./ml) replaced the growth-stimulatory properties of protamine-zinc-insulin, whilst protamine sulphate (5 µg/ml) was found to be toxic to the cells. The addition of insulin to cultures depleted of insulin increased both cell growth rates and maximum cell populations. In the defined medium, HeLa cells could only utilize glutamate when a small amount of glutamine was included. Glucose, at a level of 2 mg/ml, was shown to limit maximum cell populations. The growth yield from glucose was 295 µg cell dry weight/mg glucose. When the medium glucose concentration was increased to 4 mg/ml, HeLa cell populations in excess of 16 x 105 cells (i.e. 640 µg dry weight)/ml were routinely achieved in the defined medium supplemented with insulin. Growth is then limited by the amino acid supply. Increasing the amino acid concentration of the medium by 50% raised the maximum cell population to 23.5x105 cells (i.e. 940 µg dry weight)/ml.

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Cooling of Concentrator Photovoltaic Cells Using Mini-Scale Jet Impingement Heat Sinks

ASME 2018 12th International Conference on Energy Sustainability ◽

10.1115/es2018-7569 ◽

2018 ◽

Author(s):

Ali Radwan ◽

Meshack Hawi ◽

Mahmoud Ahmed

Keyword(s):

Heat Transfer ◽

Flow Model ◽

Three Dimensional ◽

Jet Impingement ◽

Heat Sinks ◽

Maximum Temperature ◽

Transfer Model ◽

Cell Temperature ◽

Maximum Cell ◽

T System

In this study, an efficient cooling technique for concentrator photovoltaic (CPV) cells is proposed to enhance the system electrical efficiency and extend its lifetime. To do this, a comprehensive three-dimensional conjugate heat transfer model of CPV cells layers coupled with the heat transfer and fluid flow model inside jet impingement heat sink is developed. Four different jet impingement designs are compared. The investigated designs are (A) central inlet jet, (B) Hypotenuse inlet jet, (C) staggered inlet jet, and (D) conventional jet impingement design with side drainage. The effect of coolant flowrate on the CPV/T system performance is investigated. The model is numerically simulated and validated using the available experiments. The performance of CPV system is investigated at solar concentration ratios of 20 and coolant flowrate up to 6000g/min. It is found that increasing the flowrate from 60 g/min to 600 g/min decrease the maximum cell temperature by 31°C for the configuration D while increasing the flowrate from 600 g/min to 6000 g/min reduce the cell temperature by 20.2°C. It is also concluded that at a higher flowrate of 6000g/min, all the investigated configurations relatively achieve better temperature uniformity with maximum temperature differences of 0.9 °C, 2.1 °C, 3.6 °C, and 3.9 °C for configurations A, B, C, and D respectively.

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Genome-Directed Isolation of the Key Nitrogen Fixer Leptospirillum ferrodiazotrophum sp. nov. from an Acidophilic Microbial Community

Applied and Environmental Microbiology ◽

10.1128/aem.71.10.6319-6324.2005 ◽

2005 ◽

Vol 71 (10) ◽

pp. 6319-6324 ◽

Cited By ~ 169

Author(s):

Gene W. Tyson ◽

Ian Lo ◽

Brett J. Baker ◽

Eric E. Allen ◽

Philip Hugenholtz ◽

...

Keyword(s):

Mine Drainage ◽

Sequence Data ◽

Internal Transcribed Spacer Region ◽

Free Living ◽

Maximum Cell Density ◽

Group Iii ◽

A Genome ◽

Low Diversity ◽

Maximum Cell ◽

Uncultured Microorganisms

ABSTRACT Analysis of assembled random shotgun sequence data from a low-diversity, subsurface acid mine drainage (AMD) biofilm revealed a single nif operon. This was found on a genome fragment belonging to a member of Leptospirillum group III, a lineage in the Nitrospirae phylum with no cultivated representatives. Based on the prediction that this organism is solely responsible for nitrogen fixation in the community, we pursued a selective isolation strategy to obtain the organism in pure culture. An AMD biofilm sample naturally abundant in Leptospirillum group III cells was homogenized, filtered, and serially diluted into a nitrogen-free liquid medium. The resulting culture in the terminal dilution grew autotrophically to a maximum cell density of ∼106 cells/ml, oxidizing ferrous iron as the sole energy source. 16S rRNA-internal transcribed spacer region clone library analysis confirmed that the isolate is a member of Leptospirillum group III and that the culture is axenic. We propose the name Leptospirillum ferrodiazotrophum sp. nov. for this iron-oxidizing, free-living diazotroph. This study highlights how environmental sequence data can provide insights for culturing previously uncultured microorganisms.

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Land-fast ice microalgal and phytoplanktonic communities (Adélie Land, Antarctica) in relation to environmental factors during ice break-up

Antarctic Science ◽

10.1017/s0954102003001378 ◽

2003 ◽

Vol 15 (3) ◽

pp. 353-364 ◽

Cited By ~ 19

Author(s):

C. RIAUX-GOBIN ◽

M. POULIN ◽

R. PRODON ◽

P. TREGUER

Keyword(s):

Sea Ice ◽

Early Spring ◽

Ice Melt ◽

Fast Ice ◽

Maximum Cell ◽

Cell Densities ◽

Ice Water ◽

Water Species ◽

Very High ◽

Pennate Diatoms

Annual land-fast ice, particularly an unconsolidated layer or “platelet ice-like” layer (PLI), was sampled in spring 1995 to study the spatial and short-term variations of ice-associated diatoms. Under-ice water, a lead and small polynyas were also sampled. Along a 7 km seaward transect a geographical gradient was evident, with some rare diatom species present only in the offshore PLI, whereas others (mainly pennate diatoms) were ubiquitous. The dense microphytic PLI community as well as the phytoplankton was diatom-dominated, but, within these two communities, marked differences appeared. First, the sea-ice communities (PLI and solid bottom ice) were moderately diverse (36 species), mostly composed of pennate diatoms, of which many were chain forming or tube-dwelling. Dominant taxa were Navicula glaciei, Berkeleya adeliensis, Nitzschia stellata, Amphiprora kufferathii and Nitzschia lecointei. Some differences in the distribution of the most dominant species appeared within the bottom ice and the PLI, attesting to differences in the origin or/and growing capability of these diatoms in these two ice compartments. Under-ice water species composition was mixed with sea-ice communities only on the most coastal sites and during ice melt. Maximum cell numbers were mostly noticed in the PLI, reaching up to 1010 cells l−1 and very high Chl a concentrations (exceptionally up to 9.8 mg Chl a l−1 or 1.9 g Chl a m−2, from a 10 to 20 cm thick PLI layer, close to the continent). Secondly, the phytoplankton in the lead and small polynyas had a low diversity, very low standing stocks (on an average 0.69 μg Chl a l−1) and cell densities (2 × 104 cells l−1). Some species from the polynyas were similar to those of the PLI, such as Navicula glaciei, but others were typically planktonic, such as Chaetoceros cf. neglectus. The presence of encysted cells (Chaetoceros and Chrysophytes) was also noticeable in the polynya water. In early spring no seeding process was obvious from the PLI to polynya water. A comparison with similar fast-ice diatom communities in other parts of coastal Antarctica, is presented.

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Temporal variation in maximum cell-specific nitrification rate

Water Science & Technology ◽

10.2166/wst.2010.978 ◽

2010 ◽

Vol 61 (8) ◽

pp. 2069-2073 ◽

Cited By ~ 6

Author(s):

M. Fujita ◽

K. Tsuji ◽

A. Akashi

Keyword(s):

Ammonia Oxidation ◽

Thermal Power ◽

Nitrification Rate ◽

Nitrite Oxidation ◽

Cell Numbers ◽

Oxidation Rates ◽

Batch Tests ◽

Nitrogen Loads ◽

Clone Analysis ◽

Maximum Cell

The cell numbers of ammonia-oxidising bacteria (AOBs), Nitrospira and Nitrobacter in activated sludge used to treat wastewater from a thermal power plant in Japan were examined for nine months using a real-time PCR quantification technique. AOB cell numbers ranged 2.8 × 1010–2.3 × 1011 cell/L. The amoA clone analysis showed that the only Nitrosomonas halophila was responsible for ammonia oxidation over the period. Nitrospira were in the range of 2.6 × 109–2.4 × 1010 cell/L and Nitrobacter were less than 1% as common as Nitrospira. Meanwhile, maximum nitrification rates, maximum ammonia- and nitrite-oxidation rates obtained from aerobic batch tests, ranged 0.5–1.3 mmol-N/L h and 1.0–2.5 mmol-N/L h, respectively. No clear correlations were observed between the cell numbers of AOBs or Nitrospira and their maximum rates, because the maximum cell-specific ammonia- and nitrite-oxidation rates varied remarkably over the ranges of 1.1–11.9 and 2.4–21.6 fmol-N/cell h, respectively. To explore the factors controlling maximum cell-specific nitrification rates, the relationship to influent nitrogen loads per AOB or Nitrospira cell numbers was investigated. Fairly good correlations were obtained. Considering the effluent ammonia and nitrite concentrations were zero and only Nitrosomonas halophila had a role in ammonia oxidation over the period, we conclude that the amount of nitrogen oxidised per AOB or Nitrospira cell numbers likely controls maximum cell-specific ammonia- or nitrite-oxidation rates, respectively.

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A Comparison of CO2 and N2 Foaming Behaviors of PP in a Visualization System

International Polymer Processing ◽

10.1515/ipp-2020-350512 ◽

2020 ◽

Vol 35 (5) ◽

pp. 503-517

Author(s):

Q.-P. Guo ◽

J. Wang ◽

C. B. Park

Keyword(s):

Cell Density ◽

Nucleating Agent ◽

Gas Content ◽

Experimental Conditions ◽

Maximum Cell Density ◽

Visualization System ◽

Cell Nucleation ◽

Processing Strategies ◽

Automotive Parts ◽

Maximum Cell

Abstract Understanding of polypropylene (PP) foaming is critically important to reduce the weight of automotive parts. In this study, we used a batch foaming simulation system with visualization cell, to observe the foaming behaviors of PP that is blown with CO2 and N2 under various experimental conditions. We found that the nucleating agent content, initial temperature, pressure (i. e., gas content), and pressure drop rate during foaming have a significant effect on cell nucleation and cell growth. The cell density and the void fraction of PP foamed with CO2 and N2, respectively, were separately observed and compared. It was found that under the same experimental conditions, the maximum cell density of PP foamed with CO2 was higher than that of PP foamed with N2. However, the maximum cell density of PP foamed with CO2 was determined to be lower than that of PP foamed with N2, when the same gas mole numbers were employed. Based on the experimental results, optimum foaming conditions and effective processing strategies for PP-CO2 system are suggested.

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