scholarly journals Surface Area to Volume Ratio: A Natural Variable for Bacterial Morphogenesis

2018 ◽  
Vol 26 (10) ◽  
pp. 815-832 ◽  
Author(s):  
Leigh K. Harris ◽  
Julie A. Theriot
Keyword(s):  
Surface Area ◽  
Volume Ratio ◽  
Natural Variable

Evaluation of Nanotechniques and Conventional Techniques for the Removal of Dioxins

2018 ◽  
Vol 9 (1) ◽  
pp. 79-84
Author(s):  
Vaishali V. Shahare ◽  
Rajni Grover ◽  
Suman Meena
Keyword(s):  
Soil Sample ◽  
Human Health ◽  
Surface Area ◽  
Contaminated Soil ◽  
Conventional Treatment ◽  
Volume Ratio ◽  
Soil Samples ◽  
Dioxins And Furans ◽  
Palladized Iron ◽  
The Impact

Background: The persistent dioxins/furans has caused a worldwide concern as they influence the human health. Recent research indicates that nonmaterial may prove effective in the degradation of Dioxins/furans. The nanomaterials are very reactive owing to their large surface area to volume ratio and large number of reactive sites. However, nanotechnology applications face both the challenges and the opportunities to influence the area of environmental protection. Objective: i) To study the impact of oil mediated UV-irradiations on the removal of 2,3,7,8-TCDD, 2,3,7,8-TCDF, OCDD and OCDF in simulated soil samples. ii) To compare the conventional treatment methods with the modern available nanotechniques for the removal of selected Dioxins/furans from soil samples. Methods: The present work has investigated an opportunity of the degradation of tetra and octachlorinated dioxins and furans by using oil mediated UV radiations with subsequent extraction of respective dioxins/furans from soils. The results have been compared with the available nanotechniques. Results: The dioxin congeners in the simulated soil sample showed decrease in concentration with the increase in the exposure time and intensity of UV radiations. The dechlorination of PCDD/Fs using palladized iron has been found to be effective. Conclusion: Both the conventional methods and nanotechnology have a dramatic impact on the removal of Dioxins/furans in contaminated soil. However, the nanotechniques are comparatively costlier and despite the relatively high rates of PCDDs dechlorination by Pd/nFe, small fraction of the dioxins are recalcitrant to degradation over considerable exposure times.

scholarly journals Precise regulation of the relative rates of surface area and volume synthesis in bacterial cells growing in dynamic environments

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Handuo Shi ◽  
Yan Hu ◽  
Pascal D. Odermatt ◽  
Carlos G. Gonzalez ◽  
Lichao Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Time Delay ◽  
Surface Area ◽  
Environmental Changes ◽  
Volume Ratio ◽  
Dynamic Environments ◽  
Bacterial Cells ◽  
Bacterial Growth Rate ◽  
State Size ◽  
Insight Into

AbstractThe steady-state size of bacterial cells correlates with nutrient-determined growth rate. Here, we explore how rod-shaped bacterial cells regulate their morphology during rapid environmental changes. We quantify cellular dimensions throughout passage cycles of stationary-phase cells diluted into fresh medium and grown back to saturation. We find that cells exhibit characteristic dynamics in surface area to volume ratio (SA/V), which are conserved across genetic and chemical perturbations as well as across species and growth temperatures. A mathematical model with a single fitting parameter (the time delay between surface and volume synthesis) is quantitatively consistent with our SA/V experimental observations. The model supports that this time delay is due to differential expression of volume and surface-related genes, and that the first division after dilution occurs at a tightly controlled SA/V. Our minimal model thus provides insight into the connections between bacterial growth rate and cell shape in dynamic environments.

Toward a predictive theoretical model for osmolality rise with non-humidified incubation: a randomized, multivariate response-surface study

2021 ◽  
Author(s):  
Steven F Mullen
Keyword(s):  
Mathematical Model ◽  
Response Surface ◽  
Surface Area ◽  
Embryo Culture ◽  
Culture Medium ◽  
Conflicts Of Interest ◽  
Volume Ratio ◽  
P Value ◽  
Cook Medical ◽  
Over Time

Abstract STUDY QUESTION What factors associated with embryo culture techniques contribute to the rate of medium osmolality change over time in an embryo culture incubator without added humidity? SUMMARY ANSWER The surface area-to-volume ratio of culture medium (surface area of the medium exposed to an oil overlay), as well as the density and height of the overlaying oil, all interact in a quantitative way to affect the osmolality rise over time. WHAT IS KNOWN ALREADY Factors such as medium volume, different oil types, and associated properties, individually, can affect osmolality change during non-humidified incubation. STUDY DESIGN, SIZE, DURATION Several experimental designs were used, including simple single-factor completely randomized designs, as well as a multi-factor response surface design. Randomization was performed at one or more levels for each experiment. Osmolality measurements were performed over 7 days, with up to 8 independent osmolality measurements performed per treatment group over that time. For the multi-factor study, 107 independent combinations of factor levels were assessed to develop the mathematical model. PARTICIPANTS/MATERIALS, SETTING, METHODS This study was conducted in a research laboratory setting. Commercially available embryo culture medium and oil was used. A MINC incubator without water for humidification was used for the incubation. Osmolality was measured with a vapor pressure osmometer after calibration. Viscometry and density were conducted using a rheometer, and volumetric flasks with an analytical balance, respectively. Data analyses were conducted with several commercially available software programs. MAIN RESULTS AND THE ROLE OF CHANCE Preliminary experiments showed that the surface area-to-volume ratio of the culture medium, oil density, and oil thickness above the medium all contributed significantly (P < 0.05) to the rise in osmolality. A multi-factor experiment showed that a combination of these variables, in the form of a truncated cubic polynomial, was able to predict the rise in osmolality, with these three variables interacting in the model (P < 0.05). Repeatability, as measured by the response of identical treatments performed independently, was high, with osmolality values being ± 2 of the average in most instances. In the final mathematical model, the terms of the equation were significant predictors of the outcome, with all P-values being significant, and only one P-value > 0.0001. LIMITATIONS, REASONS FOR CAUTION Although the range of values for the variables were selected to encompass values that are expected to be encountered in usual embryo culture conditions, variables outside of the range used may not result in accurate model predictions. Although the use of a single incubator type and medium type is not expected to affect the conclusions, that remains an uncertainty. WIDER IMPLICATIONS OF THE FINDINGS Using this predictive model will help to determine if one should be cautious in using a specific system and will provide guidance on how a system may be modified to provide improved stability during embryo culture. STUDY FUNDING/COMPETING INTEREST(S) This study was funded by Cook Medical. The author is a Team Lead and Senior Scientist at Cook Medical. The author has no other conflicts of interest to declare TRIAL REGISTRATION NUMBER N/A.

Biological Functionalization of Carbon Nanotubes

2004 ◽  
Vol 823 ◽  
Author(s):  
Ranjani Sirdeshmukh ◽  
Kasif Teker ◽  
Balaji Panchapakesan
Keyword(s):  
Biological Sciences ◽  
Carbon Nanotubes ◽  
Surface Area ◽  
Surface States ◽  
Volume Ratio ◽  
Surface Phenomenon ◽  
Antibody Molecule ◽  
Detection Systems ◽  
Biological Surface ◽  
Functionalization Of Carbon Nanotubes

AbstractCarbon nanotubes are known for their exceptional mechanical and unique electronic properties. The size dependant properties of nanomaterials have made them attractive to develop highly sensitive sensors and detection systems. This is especially true in biological sciences, where the efficiency of detection systems reflect on the size of the detector and the sample required for detection. At approximately 1.5 to 10nm wide, and approximately 1.5 to 2μm long, the use of carbon nanotubes as sensors in biological systems would greatly increase the sensitivity of detection and diagnostics, for a reduced sample size consisting of few individual proteins and antibodies. Since all the atoms in carbon nanotubes are surface atoms, binding proteins or antibodies to the surfaces can greatly affect their surface states, and thus their electrical and optical properties. This effect can be exploited as a basis for detecting biological surface reactions in a single protein or antibody attached to carbon nanotube surfaces.In this paper, we show the binding of fluorescently tagged antibodies in phosphate buffered saline on the surfaces of carbon nanotubes. Investigations using a confocal microscope suggest a significant interaction of the antibodies with the surfaces of the nanotubes, the intensity depending on incubation time. Since the surface area to volume ratio of CNTs is high, the use of surfactant to separate the nanotubes creates a greater surface area for antibody attachment. The interaction between CNTs and antibodies is seen to be primarily due to adsorptive surface phenomenon, between the nanotube sidewalls and antibody molecule clusters.

scholarly journals Using snowflake surface-area-to-volume ratio to model and interpret snowfall triple-frequency radar signatures

2017 ◽  
Vol 17 (19) ◽  
pp. 12011-12030 ◽  
Author(s):  
Mathias Gergely ◽  
Steven J. Cooper ◽  
Timothy J. Garrett
Keyword(s):  
Surface Area ◽  
Cross Sections ◽  
Volume Ratio ◽  
High Sensitivity ◽  
Maximum Size ◽  
Strong Impact ◽  
Triple Frequency ◽  
Bounding Volume ◽  
Wide Range ◽  
Radar Signatures

Abstract. The snowflake microstructure determines the microwave scattering properties of individual snowflakes and has a strong impact on snowfall radar signatures. In this study, individual snowflakes are represented by collections of randomly distributed ice spheres where the size and number of the constituent ice spheres are specified by the snowflake mass and surface-area-to-volume ratio (SAV) and the bounding volume of each ice sphere collection is given by the snowflake maximum dimension. Radar backscatter cross sections for the ice sphere collections are calculated at X-, Ku-, Ka-, and W-band frequencies and then used to model triple-frequency radar signatures for exponential snowflake size distributions (SSDs). Additionally, snowflake complexity values obtained from high-resolution multi-view snowflake images are used as an indicator of snowflake SAV to derive snowfall triple-frequency radar signatures. The modeled snowfall triple-frequency radar signatures cover a wide range of triple-frequency signatures that were previously determined from radar reflectivity measurements and illustrate characteristic differences related to snow type, quantified through snowflake SAV, and snowflake size. The results show high sensitivity to snowflake SAV and SSD maximum size but are generally less affected by uncertainties in the parameterization of snowflake mass, indicating the importance of snowflake SAV for the interpretation of snowfall triple-frequency radar signatures.

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