scholarly journals The Growth Kinetics of RhizoctoniasolaniAfter 1 MeV Electron Irradiation

2022 ◽  
Author(s):  
Ulyana Bliznyuk ◽  
Natalya Chulikova ◽  
Anna Malyuga
Keyword(s):  
Radial Growth ◽  
Radiation Treatment ◽  
Dose Range ◽  
Black Scurf ◽  
Phytopathogenic Fungus ◽  
Complete Suppression ◽  
Electron Radiation ◽  
Bacterial Diseases ◽  
Wide Range ◽  
Kinetics Of

Crops, especially potatoes, are prone to a wide range of fungal, viral and bacterial diseases, including black scurf caused by Rhizoctoniasolani. This study focused on the radiation treatment of the phytopathogenic fungus RhizoctoniasolaniKuhn, grown from sclerotium irradiated with 1 MeV electrons in the dose range from 20 to 4500 Gy. The doses absorbed by the sclerotia were determined using computer simulation. The growth of the fungus samples was monitored after 24, 48, 72, and 96 hours from the time of seeding. It was found that the dependence of the radial growth velocity of R. solani on the time after irradiation with doses ranging from 20to 1800 Gywas nonlinear. Irradiation at a dose over 4500 Gyled to complete suppression of the germination of R. solani sclerotia. Keywords: radiation treatment, electron radiation, radiation dose, sclerotia of Rhizoctoniasolani, Kuhn, radial velocity of growth

scholarly journals Cell-Free DNA and Circulating Tumor Cell Kinetics in a Pre-Clinical Head and Neck Cancer Model Undergoing Radiation Therapy

2020 ◽  
Author(s):  
Nidal Muhanna ◽  
Donovan Eu ◽  
Harley HL Chan ◽  
Catriona Douglas ◽  
Jason Townson ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Head And Neck ◽  
Radiation Treatment ◽  
Rabbit Model ◽  
Circulating Tumor Cell ◽  
Surface Markers ◽  
Limited Information ◽  
Liquid Biopsies ◽  
Wide Range ◽  
Kinetics Of

Abstract Background: Monitoring circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs), known as liquid biopsies, continue to be developed as diagnostic and prognostic markers for a wide variety of cancer indications, mainly due to their minimally invasive nature and ability to offer a wide range of phenotypic and genetic information. While liquid biopsies maintain significant promising benefits, there is still limited information regarding the kinetics of ctDNA and CTCs following radiation therapy which remains a vital treatment modality in head and neck cancers. This study aims to describe the kinetics of ctDNA and CTCs following radiation exposure in a preclinical rabbit model with VX2 induced buccal carcinoma. Methods: Seven rabbits were inoculated with VX2 cells in the buccal mucosa and subjected to radiation. At selected time points, blood sampling was performed to monitor differing levels of ctDNA and CTC. Plasma ctDNA was measured with quantitative PCR for papillomavirus E6 while CTCs were quantified using an immunomagnetic nanoparticles within a microfluidic device. Comparisons of CTC detection with EpCAM compared to multiple surface markers (EGFR, HER2 and PSMA) was evaluated and correlated with the tumor size.Results: Plasma ctDNA reflects the overall tumor burden within the animal model. Analysis of correlations between ctDNA with tumor and lymph node volumes showed a positive correlation (R= 0.452 and R = 0.433 [p <0.05]), respectively. Over the course of treatment, ctDNA levels declined and quickly becomes undetectable following tumor eradication. While during the course of treatment, ctDNA levels were noted to rise particularly upon initiation of radiation following scheduled treatment breaks. Levels of CTCs were observed to increase 1 week following inoculation of tumor to the primary site. For CTC detection, the use of multiple surface markers showed a greater sensitivity when compared to detection using only EpCAM. Plasma CTC levels remained elevated following radiation therapy which may account for an increased shedding of CTCs following radiation.Conclusion: This study demonstrates the utility of ctDNA and CTCs detection in response to radiation treatment in a preclinical head and neck model, allowing for better understanding of liquid biopsy applications in both clinical practice and research development.

scholarly journals Membrane current responses of skate photoreceptors.

1989 ◽  
Vol 94 (4) ◽  
pp. 633-647 ◽  
Author(s):  
M C Cornwall ◽  
H Ripps ◽  
R L Chappell ◽  
G J Jones
Keyword(s):  
Light Adaptation ◽  
Reaction Scheme ◽  
Complete Suppression ◽  
Flash Intensity ◽  
Light Responses ◽  
Wide Range ◽  
Intensity Response ◽  
Dim Light ◽  
Background Fields ◽  
Kinetics Of

Light-evoked membrane currents were recorded with suction electrodes from the outer segments of individual photoreceptors enzymatically dissociated from the skate retina. The intensity-response relation of dark-adapted cells closely followed a Michaelis function for which a half-saturating response was elicited by a flash intensity that produced about 36 photoisomerizations. Dim-light responses, as well as the early rising phase of the responses to a wide range of flash intensities, could be described by a reaction scheme that involved a series of four first-order delay stages. The number of delay stages required to model the rising phase of the photocurrents did not change in light adaptation. However, background illumination that reduced sensitivity by 1.5 log units, or a bleaching exposure that resulted in a nearly equivalent desensitization, shortened significantly the time scale of the responses. In both instances there were two- to threefold increases in the rate constants of the transitional delays, and almost complete suppression of the tail current that characterized the response of the dark-adapted cell. These findings suggest that although light adaptation alters the gain and kinetics of the transduction mechanism, the nature of the intervening processes is the same in dark- and light-adapted photoreceptors. Moreover, the results show clearly that there is no need to postulate the existence of a second class of cone-like rods to account for the remarkable ability of skate photoreceptors to respond to incremental stimuli presented on "saturating" background fields or after exposure to an intense bleaching light.

scholarly journals Cell-free DNA and circulating tumor cell kinetics in a pre-clinical head and neck Cancer model undergoing radiation therapy

BMC Cancer ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nidal Muhanna ◽  
Donovan Eu ◽  
Harley H. L. Chan ◽  
Catriona Douglas ◽  
Jason L. Townson ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Head And Neck ◽  
Radiation Treatment ◽  
Rabbit Model ◽  
Circulating Tumor Cell ◽  
Surface Markers ◽  
Limited Information ◽  
Liquid Biopsies ◽  
Wide Range ◽  
Kinetics Of

Abstract Background Monitoring circulating tumor DNA (ctDNA) and circulating tumor cells (CTCs), known as liquid biopsies, continue to be developed as diagnostic and prognostic markers for a wide variety of cancer indications, mainly due to their minimally invasive nature and ability to offer a wide range of phenotypic and genetic information. While liquid biopsies maintain significant promising benefits, there is still limited information regarding the kinetics of ctDNA and CTCs following radiation therapy which remains a vital treatment modality in head and neck cancers. This study aims to describe the kinetics of ctDNA and CTCs following radiation exposure in a preclinical rabbit model with VX2 induced buccal carcinoma. Methods Seven rabbits were inoculated with VX2 cells in the buccal mucosa and subjected to radiation. At selected time points, blood sampling was performed to monitor differing levels of ctDNA and CTC. Plasma ctDNA was measured with quantitative PCR for papillomavirus E6 while CTCs were quantified using an immunomagnetic nanoparticles within a microfluidic device. Comparisons of CTC detection with EpCAM compared to multiple surface markers (EGFR, HER2 and PSMA) was evaluated and correlated with the tumor size. Results Plasma ctDNA reflects the overall tumor burden within the animal model. Analysis of correlations between ctDNA with tumor and lymph node volumes showed a positive correlation (R = 0.452 and R = 0.433 [p < 0.05]), respectively. Over the course of treatment, ctDNA levels declined and quickly becomes undetectable following tumor eradication. While during the course of treatment, ctDNA levels were noted to rise particularly upon initiation of radiation following scheduled treatment breaks. Levels of CTCs were observed to increase 1 week following inoculation of tumor to the primary site. For CTC detection, the use of multiple surface markers showed a greater sensitivity when compared to detection using only EpCAM. Plasma CTC levels remained elevated following radiation therapy which may account for an increased shedding of CTCs following radiation. Conclusion This study demonstrates the utility of ctDNA and CTCs detection in response to radiation treatment in a preclinical head and neck model, allowing for better understanding of liquid biopsy applications in both clinical practice and research development.

Scintigraphic studies in rats. Kinetics of insulin analogues covering wide range of receptor affinities

Diabetes ◽  
1991 ◽  
Vol 40 (5) ◽  
pp. 628-632 ◽  
Author(s):  
I. Jensen ◽  
V. Kruse ◽  
U. D. Larsen
Keyword(s):  
Insulin Analogues ◽  
Wide Range ◽  
Kinetics Of

scholarly journals Combining experimental and simulation data of molecular processes via augmented Markov models

2017 ◽  
Vol 114 (31) ◽  
pp. 8265-8270 ◽  
Author(s):  
Simon Olsson ◽  
Hao Wu ◽  
Fabian Paul ◽  
Cecilia Clementi ◽  
Frank Noé
Keyword(s):  
Force Field ◽  
Structural Changes ◽  
Markov Models ◽  
Force Fields ◽  
Divide And Conquer ◽  
Simulation Data ◽  
Wide Range ◽  
Simulation And Experiment ◽  
Kinetics Of

Accurate mechanistic description of structural changes in biomolecules is an increasingly important topic in structural and chemical biology. Markov models have emerged as a powerful way to approximate the molecular kinetics of large biomolecules while keeping full structural resolution in a divide-and-conquer fashion. However, the accuracy of these models is limited by that of the force fields used to generate the underlying molecular dynamics (MD) simulation data. Whereas the quality of classical MD force fields has improved significantly in recent years, remaining errors in the Boltzmann weights are still on the order of a few kT, which may lead to significant discrepancies when comparing to experimentally measured rates or state populations. Here we take the view that simulations using a sufficiently good force-field sample conformations that are valid but have inaccurate weights, yet these weights may be made accurate by incorporating experimental data a posteriori. To do so, we propose augmented Markov models (AMMs), an approach that combines concepts from probability theory and information theory to consistently treat systematic force-field error and statistical errors in simulation and experiment. Our results demonstrate that AMMs can reconcile conflicting results for protein mechanisms obtained by different force fields and correct for a wide range of stationary and dynamical observables even when only equilibrium measurements are incorporated into the estimation process. This approach constitutes a unique avenue to combine experiment and computation into integrative models of biomolecular structure and dynamics.

scholarly journals Non-Isothermal Crystallisation Kinetics of Polypropylene at High Cooling Rates and Comparison to the Continuous Two-Domain pvT Model

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1515
Author(s):  
Jonathan Alms ◽  
Christian Hopmann ◽  
Jian Wang ◽  
Tobias Hohlweck
Keyword(s):  
Injection Moulding ◽  
Polymer Processing ◽  
Nucleation And Growth ◽  
Growth Theory ◽  
Crystallisation Kinetics ◽  
Cooling Rates ◽  
Dsc Measurements ◽  
Wide Range ◽  
High Cooling Rates ◽  
Kinetics Of

The modelling of the correlation between pressure, specific volume and temperature (pvT) of polymers is highly important for applications in the polymer processing of semi-crystalline thermoplastics, especially in injection moulding. In injection moulding, the polymer experiences a wide range of cooling rates, for example, 60 °C/min near the centre of the part and up to 3000 °C/min near the mould walls. The cooling rate has a high influence on the pvT behaviour, as was shown in the continuous two-domain pvT model (CTD). This work examined the Hoffman–Lauritzen nucleation and growth theory used in the modified Hammami model for extremely high cooling rates (up to 300,000 °C/min) by means of Flash differential scanning calorimeter (DSC) measurements. The results were compared to those of the empirical continuous two-domain pvT model. It is shown that the Hammami model is not suitable to predict the crystallisation kinetics of polypropylene at cooling rates above 600 °C/min, but that the continuous two-domain pvT model is well able to predict crystallisation temperatures at high cooling rates.

scholarly journals Automated System for Kinetic Analysis of Particle Size Distributions for Pharmaceutically Relevant Systems

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
John-Bruce D. Green ◽  
Phillip W. Carter ◽  
Yingqing Zhang ◽  
Dipa Patel ◽  
Priyanka Kotha ◽  
...  
Keyword(s):  
Particle Size ◽  
Clinical Importance ◽  
Automated System ◽  
Size Distributions ◽  
Mixing Conditions ◽  
Particle Size Distributions ◽  
Complex Formulation ◽  
Wide Range ◽  
Key Variables ◽  
Kinetics Of

Detailing the kinetics of particle formation for pharmaceutically relevant solutions is challenging, especially when considering the combination of formulations, containers, and timescales of clinical importance. This paper describes a method for using commercial software Automate with a stream-selector valve capable of sampling container solutions from within an environmental chamber. The tool was built to monitor changes in particle size distributions via instrumental particle counters but can be adapted to other solution-based sensors. The tool and methodology were demonstrated to be highly effective for measuring dynamic changes in emulsion globule distributions as a function of storage and mixing conditions important for parenteral nutrition. Higher levels of agitation induced the fastest growth of large globules (≥5 μm) while the gentler conditions actually showed a decrease in the number of these large globules. The same methodology recorded calcium phosphate precipitation kinetics as a function of [Ca2+] and pH. This automated system is readily adaptable to a wide range of pharmaceutically relevant systems where the particle size is expected to vary with time. This instrumentation can dramatically reduce the time and resources needed to probe complex formulation issues while providing new insights for monitoring the kinetics as a function of key variables.

scholarly journals Cd and Zn interactions and toxicity in ectomycorrhizal basidiomycetes in axenic culture

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4478 ◽  
Author(s):  
Vinicius H. De Oliveira ◽  
Mark Tibbett
Keyword(s):  
Radial Growth ◽  
Solid Medium ◽  
Axenic Culture ◽  
Dry Weight ◽  
Zinc Toxicity ◽  
Solid Media ◽  
Wide Range ◽  
Ecm Fungi ◽  
Ectomycorrhizal Basidiomycetes ◽  
Tolerance Indices

BackgroundMetal contamination in soils affects both above- and belowground communities, including soil microorganisms. Ectomycorrhizal (ECM) fungi are an important component in belowground community and tolerant strains have great potential in enhancing plant-based remediation techniques. We assessed cadmium and zinc toxicity in five ECM species in liquid media (Hebeloma subsaponaceum;H. cylindrosporum;H. crustuliniforme;Sclerodermasp.;Austroboletus occidentalis) and investigated the potential of Zn to alleviate Cd toxicity. Due to highly divergent results reported in the literature, liquid and solid media were compared experimentally for the first time in terms of differential toxicity thresholds in Cd and Zn interactions.MethodsA wide range of Cd and Zn concentrations were applied to ectomycorrhizal fungi in axenic cultures (in mg L−1): 0; 1; 3; 9; 27; 81; 243 for the Cd treatments, and 0; 1; 30; 90; 270; 810; 2,430 for Zn. Combined Zn and Cd treatments were also applied toH. subsaponaceumandSclerodermasp. Dry weight was recorded after 30 days, and in case of solid medium treatments, radial growth was also measured.Results and DiscussionAll species were adversely affected by high levels of Cd and Zn, andA. occidentaliswas the most sensitive, with considerable biomass decrease at 1 mg L−1Cd, whileSclerodermasp. andH. subsaponaceumwere the most tolerant, which are species commonly found in highly contaminated sites. Cd was generally 10 times more toxic than Zn, which may explain why Zn had little impact in alleviating Cd effects. In some cases, Cd and Zn interactions led to a synergistic toxicity, depending on the concentrations applied and type of media used. Increased tolerance patterns were detected in fungi grown in solid medium and may be the cause of divergent toxicity thresholds found in the literature. Furthermore, solid medium allows measuring radial growth/mycelial density as endpoints which are informative and in this case appeared be related to the high tolerance indices found inH. subsaponaceum.

scholarly journals Development of a Web-Based Supportive Care Program for Patients With Head and Neck Cancer

2020 ◽  
Vol 10 ◽  
Author(s):  
Carolyn Y. Fang ◽  
Thomas J. Galloway ◽  
Brian L. Egleston ◽  
Jessica R. Bauman ◽  
Barbara Ebersole ◽  
...  
Keyword(s):  
Head And Neck Cancer ◽  
Supportive Care ◽  
Head And Neck ◽  
Neck Cancer ◽  
Self Efficacy ◽  
Radiation Treatment ◽  
Web Based ◽  
Coping With Cancer ◽  
Wide Range ◽  
The Web

Patients undergoing radiation treatment for head and neck cancer experience significant side-effects that can impact a wide range of daily activities. Patients often report receiving insufficient information during and after treatment, which could impede rehabilitation efforts; they may also encounter practical and logistical barriers to receipt of supportive care. Thus, we developed a web-based program, My Journey Ahead, to provide information and strategies for managing symptom-focused concerns, which may be easily accessed from the patient’s home. The purpose of this study was to evaluate patient acceptability and satisfaction with the My Journey Ahead program. In Phase 1, five patients with head and neck squamous cell carcinoma (HNSCC) reviewed the web-based program and provided initial feedback, which informed program modifications. In Phase 2, 55 patients were recruited to evaluate the program. Patient assessments were obtained prior to and after use of the web-based program, and included measures of psychological distress, self-efficacy in coping with cancer-related issues, and satisfaction with the website. Among the 55 patients enrolled, 44 logged in and viewed the web-based program. Participants reported high levels of satisfaction with the information received, and indicated that the website was interesting and easy to use. Older age and higher levels of self-efficacy in coping were each associated with higher levels of satisfaction with the website. In summary, the web-based program was well-received by patients, the majority of whom found it to be informative and useful. An easy-to-use web-based program, particularly for older patients who may have difficulty locating reliable evidence-based information on the internet, may be helpful in addressing survivors’ needs in symptom management and coping with cancer.Clinical Trial Registrationhttps://clinicaltrials.gov/, NCT02442336

scholarly journals Performance Evaluation for Repair of HSGc-C5 Carcinoma Cell Using Geant4-DNA

Cancers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 6046
Author(s):  
Dousatsu Sakata ◽  
Masao Suzuki ◽  
Ryoichi Hirayama ◽  
Yasushi Abe ◽  
Masayuki Muramatsu ◽  
...  
Keyword(s):  
Dna Damage ◽  
Radiation Treatment ◽  
Carcinoma Cell ◽  
Carcinoma Cells ◽  
Model Parameters ◽  
Track Structure ◽  
V79 Cells ◽  
Damage Repair ◽  
Kinetics Of ◽  
Mev Protons

Track-structure Monte Carlo simulations are useful tools to evaluate initial DNA damage induced by irradiation. In the previous study, we have developed a Gean4-DNA-based application to estimate the cell surviving fraction of V79 cells after irradiation, bridging the gap between the initial DNA damage and the DNA rejoining kinetics by means of the two-lesion kinetics (TLK) model. However, since the DNA repair performance depends on cell line, the same model parameters cannot be used for different cell lines. Thus, we extended the Geant4-DNA application with a TLK model for the evaluation of DNA damage repair performance in HSGc-C5 carcinoma cells which are typically used for evaluating proton/carbon radiation treatment effects. For this evaluation, we also performed experimental measurements for cell surviving fractions and DNA rejoining kinetics of the HSGc-C5 cells irradiated by 70 MeV protons at the cyclotron facility at the National Institutes for Quantum and Radiological Science and Technology (QST). Concerning fast- and slow-DNA rejoining, the TLK model parameters were adequately optimized with the simulated initial DNA damage. The optimized DNA rejoining speeds were reasonably agreed with the experimental DNA rejoining speeds. Using the optimized TLK model, the Geant4-DNA simulation is now able to predict cell survival and DNA-rejoining kinetics for HSGc-C5 cells.

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