The operational flexibility of the phased culture technique, as observed by changes in the cell cycle of Candida utilis

1968 ◽  
Vol 14 (10) ◽  
pp. 1115-1126 ◽  
Author(s):  
J. Müller ◽  
P. S. S. Dawson
Keyword(s):  
Cycle Time ◽  
Doubling Time ◽  
Candida Utilis ◽  
Dry Mass ◽  
Culture Technique ◽  
Operational Flexibility ◽  
Cycle Times ◽  
Viable Cells ◽  
Cell Doubling Time ◽  
Doubling Times

The operation of a continuous phasing technique was examined with regard to synchrony and growth of Candida utilis at different doubling times. A nitrogen-limited medium and an energy-limited medium were compared. Numbers of viable cells, dry mass, ribonucleic acid (RNA), deoxyribonucleic acid (DNA), various phosphorus-fractions, and protein were measured.In a nitrogen-limited medium the continuous phasing technique provided good synchrony (65%–80%), and permitted control and variation of the doubling time up to 9 h. Dry mass, various P-fractions, and DNA increased linearly during all cycle times. The cell doubling time was adjustable to the cycle time imposed by the technique. The nitrogen source was always assimilated within 4 h, whatever the length of the cycle employed. The associated pattern of changes in the amino acid pool, protein, and RNA contents of the cells, though characteristic, underwent some modifications with change in doubling time.An inverse relationship between the amount of nitrogen available to the cells for their reproduction and the corresponding doubling time was found.In an energy (glucose)-limited medium the technique appeared to be restricted to a doubling time where the energy source in the medium lasted until the end of the cell's life cycle. The degree of synchrony was 70–75%. A variation of the doubling time by the technique did not seem possible in glucose-limited medium since no adjustment of the growth rate to the imposed cycle time could be observed.

The oxygen uptake of phased yeast cultures growing at different doubling times on nitrogen- and energy-limited media

1968 ◽  
Vol 14 (10) ◽  
pp. 1127-1131 ◽  
Author(s):  
J. Müller ◽  
P. S. S. Dawson
Keyword(s):  
Energy Source ◽  
Cell Cycle ◽  
Oxygen Uptake ◽  
Doubling Time ◽  
Candida Utilis ◽  
Limited Growth ◽  
Yeast Cultures ◽  
Limiting Nutrient ◽  
Source Limitation ◽  
Doubling Times

The oxygen uptake of Candida utilis growing in phased culture at doubling times of 4, 6, 8, and 12 hours was measured under conditions of nitrogen and energy source limitation. No abrupt doubling of oxygen uptake was observed at any stage of the cell cycle. The pattern of oxygen uptake was closely related to the assimilation of the growth-limiting nutrient. In nitrogen-limited growth, the specific oxygen uptake (Qo2) was found to decrease as the doubling time increased, but, in glucose-limited growth, no change was observed.

scholarly journals Assessing Early Heterogeneity in Doubling Times of the COVID-19 Epidemic across Prefectures in Mainland China, January–February, 2020

Epidemiologia ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 95-113 ◽  
Author(s):  
Isaac Chun-Hai Fung ◽  
Xiaolu Zhou ◽  
Chi-Ngai Cheung ◽  
Sylvia K. Ofori ◽  
Kamalich Muniz-Rodriguez ◽  
...  
Keyword(s):  
Regression Models ◽  
Doubling Time ◽  
Metropolitan Areas ◽  
Mainland China ◽  
Linear Regression Models ◽  
Case Count ◽  
Daily Time Series ◽  
The Mean ◽  
Doubling Times ◽  
Daily Time

To describe the geographical heterogeneity of COVID-19 across prefectures in mainland China, we estimated doubling times from daily time series of the cumulative case count between 24 January and 24 February 2020. We analyzed the prefecture-level COVID-19 case burden using linear regression models and used the local Moran’s I to test for spatial autocorrelation and clustering. Four hundred prefectures (~98% population) had at least one COVID-19 case and 39 prefectures had zero cases by 24 February 2020. Excluding Wuhan and those prefectures where there was only one case or none, 76 (17.3% of 439) prefectures had an arithmetic mean of the epidemic doubling time <2 d. Low-population prefectures had a higher per capita cumulative incidence than high-population prefectures during the study period. An increase in population size was associated with a very small reduction in the mean doubling time (−0.012, 95% CI, −0.017, −0.006) where the cumulative case count doubled ≥3 times. Spatial analysis revealed high case count clusters in Hubei and Heilongjiang and fast epidemic growth in several metropolitan areas by mid-February 2020. Prefectures in Hubei and neighboring provinces and several metropolitan areas in coastal and northeastern China experienced rapid growth with cumulative case count doubling multiple times with a small mean doubling time.

Fuzzy-neural-network-based fluctuation smoothing rule for reducing the cycle times of jobs with various priorities in a wafer fabrication plant: A simulation study

2009 ◽  
Vol 223 (8) ◽  
pp. 1033-1043 ◽  
Author(s):  
T Chen
Keyword(s):  
Neural Network ◽  
Cycle Time ◽  
Fuzzy Neural Network ◽  
Optimal Solution ◽  
Wafer Fabrication ◽  
Estimation Accuracy ◽  
Cycle Times ◽  
Fuzzy Neural ◽  
The Difference ◽  
Fluctuation Smoothing

This paper presents a fuzzy-neural-network-based fluctuation smoothing rule to further improve the performance of scheduling jobs with various priorities in a wafer fabrication plant. The fuzzy system is modified from the well-known fluctuation smoothing policy for a mean cycle time (FSMCT) rule with three innovative treatments. First, the remaining cycle time of a job is estimated by applying an existing fuzzy-neural-network-based approach to improve the estimation accuracy. Second, the components of the FSMCT rule are normalized to balance their importance. Finally, the division operator is applied instead of the traditional subtraction operator in order to magnify the difference in the slack and to enhance the responsiveness of the FSMCT rule. To evaluate the effectiveness of the proposed methodology, production simulation is applied to generate some test data. According to the experimental results, the proposed methodology outperforms six existing approaches in the reduction of the average cycle times. In addition, the new rule is shown to be a Pareto optimal solution for scheduling jobs in a semiconductor manufacturing plant.

Automatic 3D Cell Analysis in High-Throughput Microarray Using Micropillar and Microwell Chips

2015 ◽  
Vol 20 (9) ◽  
pp. 1178-1184 ◽  
Author(s):  
Dong Woo Lee ◽  
Moo-Yeal Lee ◽  
Bosung Ku ◽  
Do-Hyun Nam
Keyword(s):  
Standard Deviation ◽  
High Throughput ◽  
High Throughput Screening ◽  
Doubling Time ◽  
Cultured Cells ◽  
Measurement Methods ◽  
Cell Analysis ◽  
Response Curves ◽  
U251 Cell ◽  
Doubling Times

Area-based and intensity-based 3D cell viability measurement methods are compared in high-throughput screening in order to analyze their effects on the assay results (doubling time and IC50) and their repeatability. Many other 3D cell-based high-throughput screening platforms had been previously introduced, but these had not clearly addressed the effects of the two methods on the assay results and assay repeatability. In this study, the optimal way to analyze 3D cultured cells is achieved by comparing day-to-day data of doubling times and IC50 values obtained from the two methods. In experiments, the U251 cell line is grown in chips. The doubling time, based on the area of the 3D cells, was 27.8 ± 1.8 h (standard deviation: 6.6%) and 27.8 ± 3.8 h (standard deviation: 13.7%) based on the intensity of the 3D cells. The doubling time calculated by area shows a smaller standard deviation than one calculated by intensity. IC50 values calculated by both methods are very similar. The standard deviations of IC50 values for the two methods were within ±3-fold. The IC50 variations of the 12 compounds were similar regardless of the viability measurement methods and were highly related to the shape of the dose–response curves.

Design and Testing of Innovative Rotational Mould Heated by Thermal Fluid

2010 ◽  
Author(s):  
M. D. Monzo´n ◽  
A. N. Beni´tez ◽  
P. Bordo´n ◽  
P. M. Herna´ndez ◽  
M. D. Marrero ◽  
...  
Keyword(s):  
Cycle Time ◽  
Energetic Efficiency ◽  
Internal Stresses ◽  
Cycle Times ◽  
Transfer Processes ◽  
Computational Fluids Dynamics ◽  
Heating And Cooling ◽  
Computational Fluids ◽  
Plastic Parts ◽  
Design And Testing

Rotomoulded plastic parts have no internal stresses, as it is a process carried out at lower temperatures than injection moulding and no pressure is applied. The main disadvantage is the high cycle times needed. This paper focuses on reducing this cycle time and in producing a mould using standardized parts. For cycle time reducing, it is proposed to heat the mould by thermal fluid in continuous circulation; heat transfer processes have been studied for over 20 different configurations of the oil’s inlet – outlet, obtaining acceptable results with a manifold with 25 perforations in the front and rear faces. This configuration has been optimized by computational fluids dynamics, allowing reducing heating and cooling time and improving the energetic efficiency and the uniformity of heating. Design, simulations and testing of a 100 mm3 cube have been carried out in order to produce a standardized mould; this mould consists in some standardized parts and a nickel shell, obtained by rapid prototyping and electroforming process. This shell can be removed from the rest of elements in the mould, allowing thus to obtain parts with any other geometry just by changing the nickel shell. An experimental machine for testing has been developed as well.

A Head-to-Head Comparison of Hydrogen Peroxide Vapor and Aerosol Room Decontamination Systems

2011 ◽  
Vol 32 (9) ◽  
pp. 831-836 ◽  
Author(s):  
T. Holmdahl ◽  
P. Lanbeck ◽  
M. Wullt ◽  
M. H. Walder
Keyword(s):  
Hydrogen Peroxide ◽  
Cycle Time ◽  
New Technologies ◽  
Biological Indicators ◽  
The Other ◽  
Test Room ◽  
Cycle Times ◽  
Hydrogen Peroxide Vapor ◽  
In Vitro Comparison

Objective.New technologies have emerged in recent years for the disinfection of hospital rooms and equipment that may not be disinfected adequately using conventional methods. There are several hydrogen peroxide–based area decontamination technologies on the market, but no head-to-head studies have been performed.Design.We conducted a head-to-head in vitro comparison of a hydrogen peroxide vapor (HPV) system (Bioquell) and an aerosolized hydrogen peroxide (aHP) system (Sterinis).Setting.The tests were conducted in a purpose-built 136-m3test room.Methods.One HPV generator and 2 aHP machines were used, following recommendations of the manufacturers. Three repeated tests were performed for each system. The microbiological efficacy of the 2 systems was tested using 6-log Tyvek-pouchedGeobacillus stearo-thermophilusbiological indicators (BIs). The indicators were placed at 20 locations in the first test and 14 locations in the subsequent 2 tests for each system.Results.All BIs were inactivated for the 3 HPV tests, compared with only 10% in the first aHP test and 79% in the other 2 aHP tests. The peak hydrogen peroxide concentration was 338 ppm for HPV and 160 ppm for aHP. The total cycle time (including aeration) was 3 and 3.5 hours for the 3 HPV tests and the 3 aHP tests, respectively. Monitoring around the perimeter of the enclosure with a handheld sensor during tests of both systems did not identify leakage.Conclusion.One HPV generator was more effective than 2 aHP machines for the inactivation ofG. stearothermophilusBIs, and cycle times were faster for the HPV system.

Experimental results on mammalian cells growing in vitro in deuterated medium for neutron-scattering studies

1977 ◽  
Vol 25 (1) ◽  
pp. 87-94
Author(s):  
J. Murphy ◽  
C. Desaive ◽  
W. Giaretti ◽  
F. Kendall ◽  
C. Nicolini
Keyword(s):  
Mammalian Cells ◽  
Doubling Time ◽  
Deuterium Oxide ◽  
Initial Period ◽  
Lag Phase ◽  
Suspended Cell ◽  
Human Diploid Fibroblasts ◽  
Cell Doubling Time ◽  
Sv 40 Virus

SV-40 virus-transfromed human diploid fibroblasts (2RA) were grown in a monolayer on plastic Petri dishes in an aqueous medium deuterated to different concentrations of deuterium oxide: 10, 20, 30, up to 60%. The cells must be acclimatized to concentrations higher than 20% D2O by stepping them from a lower initial concentration during their exponential growth. The increase of cell doubling time with increasing deuterium concentrations seems to correlate, at least at 20% D20, with an initial period of suspended cell growth (lag-phase), and is qualitatively similar to that previously reported for Escherichia coli.

G alpha(i-2) mediates renal LLC-PK1 growth by a Raf-independent activation of p42/p44 MAP kinase

1997 ◽  
Vol 272 (2) ◽  
pp. F273-F282 ◽  
Author(s):  
T. B. Kinane ◽  
I. Kang ◽  
A. Chu ◽  
S. H. Chin ◽  
L. Ercolani
Keyword(s):  
Cell Growth ◽  
Protein Kinases ◽  
Doubling Time ◽  
Active Form ◽  
Renal Cells ◽  
Downstream Effectors ◽  
Mitogen Activated Protein ◽  
Cell Doubling Time ◽  
Cell Growth And Differentiation ◽  
Maximal Expression

The protooncogene G alpha(i-2) plays a pivotal role in signaling pathways that control renal cell growth and differentiation. Mitogen-activated protein kinases (MAPKs) are potential downstream effectors for G alpha(i-2) in these pathways. In predifferentiated LLC-PK1 renal cells, the temporal maximal expression of G alpha(i-2) coincided with maximal activation of MAPK(p42/p44). By contrast, pertussis toxin treatment of these cells inhibited cell growth and reduced MAPK(p42/p44) activity by 30%. These findings reflected upstream activation of MAPK kinase (MEK1), as transient transfection of cells with a plasmid encoding a constitutively active form of MEK1 increased MAPK(p42/p44) activity and cell growth, whereas treatment with PD-098059, an inhibitor of MEK1 activity, reduced MAPK(p42/p44) activity and cell growth. Expression of a guanosinetriphosphatase (GTPase)-deficient G alpha(i-2) in these cells increased MAPK(p42/p44) activity and correspondingly reduced cell doubling time from 24 to 10 h without altering the activity of Raf-1 or c-Jun/stress-activated protein kinases (SAPKs). By contrast, expression of a GTPase-deficient G alpha(i-3) in these cells reduced both their cell doubling time by 30% and MAPK(p42/p44) activity by 60%. As the known MEKK isoforms (MEKK1, -2, and -3) can also activate SAPKs, these findings suggest the GTP-charged G alpha(i-2) subunit transduces growth signals in renal cells via activation of MAPK(p42/p44) and that such activation may be linked to pathways containing novel MEKK isoforms that preferentially activate MEKs.

scholarly journals Administrative Preparedness Strategies: Expediting Procurement and Contracting Cycle Times During an Emergency

2017 ◽  
Vol 132 (3) ◽  
pp. 294-297
Author(s):  
David Hurst ◽  
Sharon Sharpe ◽  
Valerie A. Yeager
Keyword(s):  
Public Health ◽  
Cycle Time ◽  
Emergency Preparedness ◽  
Public Health Emergency ◽  
Open Market ◽  
Cycle Times ◽  
Goods And Services ◽  
Cooperative Agreements ◽  
Hospital Preparedness ◽  
Cooperative Purchasing

We assessed whether administrative preparedness processes that were intended to expedite the acquisition of goods and services during a public health emergency affect estimated procurement and contracting cycle times. We obtained data from 2014-2015 applications to the Hospital Preparedness Program and Public Health Emergency Preparedness (HPP-PHEP) cooperative agreements. We compared the estimated procurement and contracting cycle times of 61 HPP-PHEP awardees that did and did not have certain administrative processes in place. Certain processes, such as statutes allowing for procuring and contracting on the open market, had an effect on reducing the estimated cycle times for obtaining goods and services. Other processes, such as cooperative purchasing agreements, also had an effect on estimated procurement time. For example, awardees with statutes that permitted them to obtain goods and services in the open market had an average procurement cycle time of 6 days; those without such statutes had a cycle time of 17 days ( P = .04). PHEP awardees should consider adopting these or similar processes in an effort to reduce cycle times.

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