scholarly journals Thermal Analysis of Whole Bacterial Cells Exposed to Potassium Permanganate Using Differential Scanning Calorimetry: a Biphasic Dose-Dependent Response to Stress

2009 ◽  
Vol 9 ◽  
pp. 109-117 ◽  
Author(s):  
Marina K. Abuladze ◽  
Victor M. Sokhadze ◽  
Emma N. Namchevadze ◽  
E. Kiziria ◽  
Leila V. Tabatadze ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Potassium Permanganate ◽  
Cell Level ◽  
Scanning Calorimetry ◽  
Whole Cell ◽  
Melting Heat ◽  
Response To Stress ◽  
The Impact ◽  
Arthrobacter Oxydans ◽  
Dose Dependent

Differential scanning calorimetry (DSC) was applied to estimate the impact of the toxic oxidant potassium permanganate (PM) on the intracellular structural and functional alterations at whole cell level using soil bacteriaArthrobacter oxydansas a model culture. Differential scanning calorimetry (DSC) was applied in order to estimate the impact of the toxic oxidant potassium permanganate (PM) on the intracellular structural and functional alterations at the whole cell level using the soil bacteria Arthrobacter oxydans as a model culture. We compared the total melting heat and the temperature of DNA-protein complex (DNP) melting at the PM application prior to the calorimetry measurement and after 24-h exposure at the concentration range 0.02–1.4 mM. The initial oxidative effect caused changes in the pattern of the whole cell melting spectra (mainly at the temperature range 56–78°C), the decrease of Tmax°C DNP melting, and did not influence significantly the total heat of bacterial melting at different concentrations of PM. The prolonged effect of permanganate up to 24 h was characterized by a biphasic dose-dependent response to stress estimated by the DSC technique and the colony-forming assay. The low doses of PM (0.02 and 0.2 mM) stimulated cell proliferation, and increased the total whole cell melting heat and the temperature of DNP melting. The toxic effect of PM up to 0.04 mMreduced cell viability, changed the character of multipeaked thermograms, and lowered the total melting heat and the temperature of DNP melting in a concentration-dependent manner. This study presents the DSC method for evaluating and monitoring the effects of exposure to potential human and environmental toxicants.

scholarly journals Naringenin Release to Biomembrane Models by Incorporation into Nanoparticles. Experimental Evidence Using Differential Scanning Calorimetry

Surfaces ◽  
2021 ◽  
Vol 4 (4) ◽  
pp. 295-305
Author(s):  
Cristina Torrisi ◽  
Marco Di Guardia ◽  
Francesco Castelli ◽  
Maria Grazia Sarpietro
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heart Tissue ◽  
Protective Role ◽  
Delivery Systems ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Drug Bioavailability ◽  
Cell Level ◽  
Scanning Calorimetry ◽  
Beneficial Effects

Naringenin (4′,5,7-trihydroxyflavanone-7-rhamnoglucosideor naringenin-7-rhamnoglucoside), a flavonoid present in large quantities in citrus, has different beneficial effects on human health as an antioxidant, free radical scavenger, anti-inflammatory, carbohydrate metabolism promoter, and immune system modulator. Different studies have shown that this substance also has a hypoglycemic and antihypertensive effect, reduces cholesterol and triglycerides, and plays an important protective role in the heart tissue; moreover, it provides neuroprotection against various neurological disorders such as Parkinson’s disease and unpredictable chronic stress-induced depression. Despite these advantages, Naringenin is poorly absorbed, and the small percentage absorbed is rapidly degraded by the liver, as a result losing its activity. Several approaches have been attempted to overcome these obstacles, among them, nanotechnology, with the use of Drug Delivery Systems (DDS) as Solid Lipid Nanoparticles (SLN) and Nanostructured Lipid Carriers (NLC). DDS can, in fact, improve the drug bioavailability. The aim of this study was to develop and characterize SLN and NLC containing Naringenin and to evaluate the ability of these nanoparticles to release Naringenin at the cell level using biomembrane models represented by Multilamellar Vesicles (MLV). These studies were performed using Differential Scanning Calorimetry, a powerful technique to detect the interaction of drugs and delivery systems with MLV. It was shown that Naringenin could be better incorporated into NLC with respect to SLN and that Naringenin could be released by NLC into the biomembrane model. Therefore, suggesting the administration of Naringenin loaded into nanoparticles could help avoid the disadvantages associated with the use of the free molecule.

The thermal fission-induced crystalline-to-amorphous transformation in U6Fe

1988 ◽  
Vol 3 (3) ◽  
pp. 453-460 ◽  
Author(s):  
Don M. Parkin ◽  
Reed O. Elliott
Keyword(s):  
Differential Scanning Calorimetry ◽  
Crystallization Behavior ◽  
Amorphous Material ◽  
Nucleation And Growth ◽  
Local Defect ◽  
Scanning Calorimetry ◽  
Dose Dependent ◽  
Limited Process ◽  
Total Resistivity ◽  
Crystalline Matrix

The crystalline-to-amorphous transformation in U6Fe produced by thermal fission fragment damage was studied using resistivity and differential scanning calorimetry. The results are described in terms of a model of radiation-produced defect buildup in the crystalline matrix followed by transformation of small regions to an amorphous phase when a critical local defect concentration is reached. This can occur directly in a single cascade or from cascade overlap. The total resistivity is modeled assuming an inhomogeneous media consisting of a crystalline matrix containing a dose-dependent concentration of defects and amorphous zones. The crystallization behavior is initially, starting at Tc = 388 K, a kinetically limited process of shrinkage of amorphous zones that gradually transforms to nucleation and growth in fully amorphous material at Tc = 555 K.

In vivo characterization of thermal stabilities of Aeropyrum pernix cellular components by differential scanning calorimetry

2007 ◽  
Vol 53 (9) ◽  
pp. 1038-1045 ◽  
Author(s):  
Igor Milek ◽  
Miha Črnigoj ◽  
Nataša Poklar Ulrih ◽  
Gönül Kaletunç
Keyword(s):  
Heat Treatment ◽  
Differential Scanning Calorimetry ◽  
Optical Data ◽  
Lag Phase ◽  
Scanning Calorimetry ◽  
Thermal Stabilities ◽  
Whole Cell ◽  
Whole Cells ◽  
Aeropyrum Pernix ◽  
Cellular Components

Revival studies of Aeropyrum pernix show that the viability of cells and cell recovery after heat treatment depends on the temperature of treatment. Differential scanning calorimetry (DSC) is used to analyze the relative thermal stabilities of cellular components of A. pernix and to identify the cellular components responsible for the observed lag phase and reduced maximum growth following a heat treatment. DSC thermograms show 5 visible endothermic transitions with 2 major transitions. DSC analysis of isolated crude ribosomes aids the assignment of the 2 major peaks observed in whole-cell thermograms to denaturation of ribosomal structures. A comparison of partial and immediate full rescan thermograms of A. pernix whole cells indicates that both major peaks represent irreversible thermal transitions. A DNA peak is also identified in the whole-cell thermogram by comparison with the optical data of isolated pure DNA. DNA melting is shown to be irreversible in dilute solution, whereas it is partially reversible in whole cells, owing at least in part, to restricted volume effects. In contrast to mesophilic organisms, hyperthermophilic A. pernix ribosomes are more thermally stable than DNA, but in both organisms, irreversible changes leading to cell death occur owing to ribosomal denaturation.

scholarly journals Solid state and sub-cooled liquid vapour pressures of substituted dicarboxylic acids using Knudsen Effusion Mass Spectrometry (KEMS) and Differential Scanning Calorimetry

2010 ◽  
Vol 10 (10) ◽  
pp. 4879-4892 ◽  
Author(s):  
A. M. Booth ◽  
M. H. Barley ◽  
D. O. Topping ◽  
G. McFiggans ◽  
A. Garforth ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Differential Scanning Calorimetry ◽  
Solid State ◽  
Dicarboxylic Acids ◽  
Estimation Methods ◽  
Scanning Calorimetry ◽  
Knudsen Effusion ◽  
Oh Groups ◽  
Knudsen Effusion Mass Spectrometry ◽  
The Impact

Abstract. Solid state vapour pressures of a selection of atmospherically important substituted dicarboxylic acids have been measured using Knudsen Effusion Mass Spectrometry (KEMS) over a range of 20 K (298–318 K). Enthalpies of fusion and melting points obtained using Differential Scanning Calorimetry (DSC) were used to obtain sub-cooled liquid vapour pressures. They have been compared to estimation methods used on the E-AIM website. These methods are shown to poorly represent – OH groups in combination with COOH groups. Partitioning calculations have been performed to illustrate the impact of the different estimation methods on organic aerosol mass compared to the use of experimental data.

scholarly journals Solid state and sub-cooled liquid vapour pressures of substituted dicarboxylic acids using Knudsen Effusion Mass Spectrometry (KEMS) and Differential Scanning Calorimetry

2010 ◽  
Vol 10 (2) ◽  
pp. 5717-5749
Author(s):  
A. M. Booth ◽  
M. H. Barley ◽  
D. O. Topping ◽  
G. McFiggans ◽  
A. Garforth
Keyword(s):  
Mass Spectrometry ◽  
Differential Scanning Calorimetry ◽  
Solid State ◽  
Dicarboxylic Acids ◽  
Estimation Methods ◽  
Scanning Calorimetry ◽  
Knudsen Effusion ◽  
Oh Groups ◽  
Knudsen Effusion Mass Spectrometry ◽  
The Impact

Abstract. Solid state vapour pressures of a selection of substituted dicarboxylic acids have been measured using Knudsen Effusion Mass Spectrometry (KEMS). Enthalpies of fusion and melting points obtained using Differential Scanning Calorimetry (DSC) were used to obtain sub-cooled liquid vapour pressures. They have been compared to estimation methods used on the E-AIM website. These methods are shown to poorly represent -OH groups in combination with COOH groups. Partitioning calculations have been performed to illustrate the impact of the different estimation methods on organic aerosol mass compared to the use of experimental data.

The Impact of the Composition of the Crude Oils on the Wax Crystallization

2014 ◽  
Vol 625 ◽  
pp. 196-200 ◽  
Author(s):  
Arya Hosseinipour ◽  
Khalik M. Sabil ◽  
Andhy Arya Ekaputra ◽  
Azuraien B. Japper ◽  
Lukman B. Ismail
Keyword(s):  
Differential Scanning Calorimetry ◽  
High Pressure ◽  
Crude Oil ◽  
Crude Oils ◽  
Solubility Curve ◽  
Scanning Calorimetry ◽  
Wax Precipitation ◽  
Wax Appearance Temperature ◽  
Wax Crystallization ◽  
The Impact

One of the major problems in petroleum industry is wax precipitation and deposition. The component’s compositional and structural analysis of the crude oils is key factors to be studied to mitigate wax formation and precipitation tendency for the betterment of the crude oil flowability. In this work, the compositions and structures of two Malaysian and Sudanese crude oil samples were determined to investigate their effects on wax precipitation. The GC/MS was used to analyze hydrocarbon components. For this work, high pressure micro differential scanning calorimetry (HPμDSC) is used to determine the wax crystallization point and solubility curve. Results showed a linear relationship between wax appearance temperature (WAT) and weight percentage of component in the crude oil having > 14 carbon atoms. In addition, the effect of temperature on the amount of wax precipitation has also been investigated. Keywords: N-paraffin, Wax appearance temperature, Wax precipitation, High pressure micro differential scanning calorimetry

scholarly journals Novel Electrospun Pullulan Fibers Incorporating Hydroxypropyl-β-Cyclodextrin: Morphology and Relation with Rheological Properties

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2558
Author(s):  
Deepak Poudel ◽  
Sarah Swilley-Sanchez ◽  
Sean O’keefe ◽  
John Matson ◽  
Timothy Long ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Differential Scanning Calorimetry ◽  
Biomedical Applications ◽  
Synthetic Polymers ◽  
Fiber Morphology ◽  
Rheological Characterization ◽  
Scanning Calorimetry ◽  
Naturally Occurring ◽  
The Impact ◽  
The Relationship

Fibers produced by electrospinning from biocompatible, biodegradable and naturally occurring polymers have potential advantages in drug delivery and biomedical applications because of their unique functionalities. Here, electrospun submicron fibers were produced from mixtures containing an exopolysaccharide (pullulan) and a small molecule with hosting abilities, hydroxypropyl-β-cyclodextrin (HP-β-CD), thus serving as multi-functional blend. The procedure used water as sole solvent and excluded synthetic polymers. Rheological characterization was performed to evaluate the impact of HP-β-CD on pullulan entanglement concentration (CE); the relationship with electrospinnability and fiber morphology was investigated. Neat pullulan solutions required three times CE (~20% w/v pullulan) for effective electrospinning and formation of bead-free nanofibers. HP-β-CD (30% w/v) facilitated electrospinning, leading to the production of continuous, beadless fibers (average diameters: 853-1019 nm) at lower polymer concentrations than those required in neat pullulan systems, without significantly shifting the polymer CE. Rheological, Differential Scanning Calorimetry (DSC) and Dynamic Light Scattering (DLS) measurements suggested that electrospinnability improvement was due to HP-β-CD assisting in pullulan entanglement, probably acting as a crosslinker. Yet, the type of association was not clearly identified. This study shows that blending pullulan with HP-β-CD offers a platform to exploit the inherent properties and advantages of both components in encapsulation applications.

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