Effects of physical and chemical conditions on the in vitro oxidation of tea leaf catechins

Background The durability of breast implant material is associated with failure probability, increasing with time from implantation. The current study avoided the bias introduced by biological factors, to systematically investigate the degradation over time of shell materials. The same fundamental physical and chemical conditions were maintained (temperature and pH) throughout the study, to decouple biological aspects from the degradation process. Methods Six virgin implants of 2 brands were submitted to the in vitro degradation process, mechanical testing of shell materials, surface change analysis (via scanning electron microscopy [SEM]) and chemical composition analysis by Fourier transform infrared (FTIR) spectroscopy. Results FTIR results showed that the principal chemical bonds of the material remained intact after 12 weeks of degradation. Apparently the implants’ shell structures remained unchanged. Despite this observation, there were statistically significant differences between strain at failure at different time points for the shells of both brands, translated into a stiffening of the material over time. Conclusions Material stiffening is reported as an indicator of material degradation. This altered mechanical behavior, added to the mechanical friction from tissue–tissue and tissue–implant contact and to the external mechanical loading (physical activity), may alter the material performance in women's bodies. Ultimately these changes may affect the implants’ durability. Further work is needed to understand the biological aspects of the degradation process and their impact on implant durability.

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Modern technologies of increasing the tolerance of in vitro cultured plants to ex vitro conditions

Faktori eksperimental'noi evolucii organizmiv ◽

10.7124/feeo.v26.1347 ◽

2020 ◽

Vol 26 ◽

pp. 183-189

Author(s):

L. R. Hrytsak ◽

N. M. Drobyk

Keyword(s):

Ex Vitro ◽

Adaptive Potential ◽

In Vitro Plants ◽

Plant Cultivation ◽

Planting Material ◽

Chemical Conditions ◽

Cultivation In Vitro ◽

Physical And Chemical ◽

Modern Technologies

Aim. To analyze the experience of Ukrainian and foreign scientists on technologies to increase the adaptive potential of cultivated in vitro plants to ex vitro conditions. Results. Modern acclimatization technologies are mainly aimed at improving the methods of adaptation of planting material of in vitro collections to ex vitro conditions. Much less attention is paid to technologies to increase plant resilience at the stage of their multiplication and growth in vitro. Integration and systematization of research results of a large number of scientists is allowed to describe the main strategies and methodological techniques, which implementation can significantly increase the adaptive potential of in vitro plants. Conclusions. Optimization of physical and chemical conditions of plant cultivation in vitro can induce changes in their phenotype, intensity of photosynthetic reactions, water balance, which increases the adaptive potential of plants and facilitates the process of their acclimatization to ex vitro conditions. Key words: in vitro plants, acclimatization to ex vitro conditions, adaptive potential, technology.

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Ultrastructural Investigations of the Contractile Filaments of Amoebae

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050950 ◽

1974 ◽

Vol 32 ◽

pp. 188-189

Author(s):

P.L. Moore

Keyword(s):

Cytoplasmic Streaming ◽

Three Dimensional ◽

Freeze Fracture ◽

Amoeboid Movement ◽

Different Types ◽

Chemical Conditions ◽

Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

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Permeability to albumin in isolated coronary venules

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1993.265.2.h543 ◽

1993 ◽

Vol 265 (2) ◽

pp. H543-H552 ◽

Cited By ~ 7

Author(s):

Y. Yuan ◽

W. M. Chilian ◽

H. J. Granger ◽

D. C. Zawieja

Keyword(s):

Permeability Coefficient ◽

Filtration Rate ◽

Intraluminal Pressure ◽

Apparent Permeability ◽

Filtration Pressure ◽

Diffusive Permeability ◽

Apparent Permeability Coefficient ◽

Chemical Conditions ◽

Physical And Chemical ◽

Intravascular Pressure

This study reports measurements of albumin permeability in isolated coronary venules. The isolated microvessel technique allows the quantification of transmural exchange of macromolecules under tightly controlled physical and chemical conditions. Transvenular exchange of albumin was studied in isolated coronary venules during alterations in filtration rate caused by changes in intravascular pressure. The apparent permeability coefficient of albumin (Pa) at an intraluminal pressure of 11 cmH2O was 3.92 +/- 0.43 x 10(-6) cm/s. Elevating intraluminal pressure to 16 and 21 cmH2O increased Pa to 5.13 +/- 0.57 x 10(-6) and 6.78 +/- 0.66 x 10(-6) cm/s, respectively. Calculation of the true diffusive permeability coefficient of albumin (Pd) at zero filtration rate was 1.54 x 10(-6) cm/s. The product of hydraulic conductance (Lp) and (1 - sigma), where sigma is the solute reflection coefficient, was 3.25 x 10(-7) cm.s-1 x cmH2O-1. At a net filtration pressure of 4-5 cmH2O, diffusion accounts for > 60% of total albumin transport across the venular wall. Transmural albumin flux is very sensitive to filtration rate, rising 6.7% for each cmH2O elevation of net filtration pressure. At 11 cmH2O net filtration pressure, convection accounts for nearly 70% of net albumin extravasation from the venular lumen. We suggest that the isolated coronary venule is a suitable preparation for the study of solute exchange in the heart.

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Origin of Life on Mars: Suitability and Opportunities

Life ◽

10.3390/life11060539 ◽

2021 ◽

Vol 11 (6) ◽

pp. 539

Author(s):

Benton C. Clark ◽

Vera M. Kolb ◽

Andrew Steele ◽

Christopher H. House ◽

Nina L. Lanza ◽

...

Keyword(s):

Origin Of Life ◽

Energy Sources ◽

Early Earth ◽

Sediment Samples ◽

Life On Mars ◽

Eventual Return ◽

History Of ◽

Early Mars ◽

Chemical Conditions ◽

Physical And Chemical

Although the habitability of early Mars is now well established, its suitability for conditions favorable to an independent origin of life (OoL) has been less certain. With continued exploration, evidence has mounted for a widespread diversity of physical and chemical conditions on Mars that mimic those variously hypothesized as settings in which life first arose on Earth. Mars has also provided water, energy sources, CHNOPS elements, critical catalytic transition metal elements, as well as B, Mg, Ca, Na and K, all of which are elements associated with life as we know it. With its highly favorable sulfur abundance and land/ocean ratio, early wet Mars remains a prime candidate for its own OoL, in many respects superior to Earth. The relatively well-preserved ancient surface of planet Mars helps inform the range of possible analogous conditions during the now-obliterated history of early Earth. Continued exploration of Mars also contributes to the understanding of the opportunities for settings enabling an OoL on exoplanets. Favoring geochemical sediment samples for eventual return to Earth will enhance assessments of the likelihood of a Martian OoL.

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Physicochemical Characteristics of Arginine Enriched NaF Varnish: An In Vitro Study

Polymers ◽

10.3390/polym12122998 ◽

2020 ◽

Vol 12 (12) ◽

pp. 2998

Author(s):

Mohammed Nadeem Bijle ◽

Manikandan Ekambaram ◽

Edward Lo ◽

Cynthia Yiu

Keyword(s):

Molecular Dynamics ◽

Physical Properties ◽

Artificial Saliva ◽

Chemical Properties ◽

In Vitro Study ◽

Physicochemical Characteristics ◽

Vitro Study ◽

Physical And Chemical ◽

Stable Matrix

The in vitro study objectives were to investigate the effect of arginine (Arg) incorporation in a 5% sodium fluoride (NaF) varnish on its physical and chemical properties including F/Arg release. Six experimental formulations were prepared with L-arginine (L-Arg) and L-arginine monohydrochloride at 2%, 4%, and 8% w/v in a 5% NaF varnish, which served as a control. The varnishes were subjected to assessments for adhesion, viscosity, and NaF extraction. Molecular dynamics were simulated to identify post-dynamics total energy for NaF=Arg/Arg>NaF/Arg<NaF concentrations. The Arg/F varnish release profiles were determined in polyacrylic lactate buffer (pH-4.5; 7 days) and artificial saliva (pH-7; 1 h, 24 h, and 12 weeks). Incorporation of L-Arg in NaF varnish significantly influences physical properties ameliorating retention (p < 0.001). L-Arg in NaF varnish institutes the Arg-F complex. Molecular dynamics suggests that NaF>Arg concentration denotes the stabilized environment compared to NaF<Arg (p < 0.001). The 2% Arg-NaF exhibits periodic perennial Arg/F release and shows significantly higher integrated mean F release than NaF (p < 0.001). Incorporating 2% L-arginine in 5% NaF varnish improves its physical properties and renders a stable matrix with enduring higher F/Arg release than control.

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Microalgae biomass as an alternative ingredient in cookies: Sensory, physical and chemical properties, antioxidant activity and in vitro digestibility

Algal Research ◽

10.1016/j.algal.2017.07.017 ◽

2017 ◽

Vol 26 ◽

pp. 161-171 ◽

Cited By ~ 69

Author(s):

Ana Paula Batista ◽

Alberto Niccolai ◽

Patrícia Fradinho ◽

Solange Fragoso ◽

Ivana Bursic ◽

...

Keyword(s):

Antioxidant Activity ◽

Chemical Properties ◽

In Vitro Digestibility ◽

Physical And Chemical Properties ◽

Microalgae Biomass ◽

Alternative Ingredient ◽

Physical And Chemical ◽

And Chemical Properties

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Size-controlled human adipose-derived stem cell spheroids hybridized with single-segmented nanofibers and their effect on viability and stem cell differentiation

Biomaterials Research ◽

10.1186/s40824-021-00215-9 ◽

2021 ◽

Vol 25 (1) ◽

Author(s):

Jinkyu Lee ◽

Sangmin Lee ◽

Sung Min Kim ◽

Heungsoo Shin

Keyword(s):

Stem Cell ◽

Cell Function ◽

Average Length ◽

Three Dimensional ◽

Stem Cell Differentiation ◽

Cell Spheroids ◽

Significant Difference ◽

Vitro Analysis ◽

Physical And Chemical

Abstract Background Fabrication of three-dimensional stem cell spheroids have been studied to improve stem cell function, but the hypoxic core and limited penetration of nutrients and signaling cues to the interior of the spheroid were challenges. The incorporation of polymers such as silica and gelatin in spheroids resulted in relatively relaxed assembly of composite spheroids, and enhancing transport of nutrient and biological gas. However, because of the low surface area between cells and since the polymers were heterogeneously distributed throughout the spheroid, these polymers cannot increase the cell to extracellular matrix interactions needed to support differentiation. Methods We developed the stem cell spheroids that incorporate poly(ι-lactic acid) single-segmented fibers synthesized by electrospinning and physical and chemical fragmentation. The proper mixing ratio was 2000 cells/μg fibers (average length of the fibers was 50 μm - 100 μm). The SFs were coated with polydopamine to increase cell binding affinity and to synthesize various-sized spheroids. The function of spheroids was investigated by in vitro analysis depending on their sizes. For statistical analysis, Graphpad Prism 5 software (San Diego, CA, USA) was used to perform one-way analysis of variance ANOVA with Tukey’s honest significant difference test and a Student’s t-test (for two variables) (P < 0.05). Results Spheroids of different sizes were created by modulating the amount of cells and fibers (0.063 mm2–0.322 mm2). The fibers in the spheroid were homogenously distributed and increased cell viability, while cell-only spheroids showed a loss of DNA contents, internal degradation, and many apoptotic signals. Furthermore, we investigated stemness and various functions of various-sized fiber-incorporated spheroids. In conclusion, the spheroid with the largest size showed the greatest release of angiogenic factors (released VEGF: 0.111 ± 0.004 pg/ng DNA), while the smallest size showed greater effects of osteogenic differentiation (mineralized calcium: 18.099 ± 0.271 ng/ng DNA). Conclusion The spheroids incorporating polydopamine coated single-segmented fibers showed enhanced viability regardless of sizes and increased their functionality by regulating the size of spheroids which may be used for various tissue reconstruction and therapeutic applications.

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New thiazacridine agents: Synthesis, physical and chemical characterization, and in vitro anticancer evaluation

Human & Experimental Toxicology ◽

10.1177/0960327116680274 ◽

2016 ◽

Vol 36 (10) ◽

pp. 1059-1070 ◽

Cited By ~ 2

Author(s):

MBO Chagas ◽

NCC Cordeiro ◽

KMR Marques ◽

MG Rocha Pitta ◽

MJBM Rêgo ◽

...

Keyword(s):

Cell Cycle ◽

Cytotoxic Activity ◽

Cell Cycle Progression ◽

Antitumor Agents ◽

Flow Cytometric Analysis ◽

Cell Lineage ◽

Chemical Characterization ◽

Flow Cytometric ◽

Physical And Chemical

A series of new thiazacridine agents were synthesized and evaluated as antitumor agents, in terms of not only their cytotoxicity but also their selectivity. The cytotoxicity assay confirmed that all compounds showed cytotoxic activity and selectivity. The new compound, 3-acridin-9-ylmethyl-5-(5-bromo-1 H-indol-3-ylmethylene)-thiazolidine-2,4-dione (LPSF/AA29 – 7a), proved to be the most promising compound as it presents lower half-maximal inhibitory concentration (IC50) values (ranging from 0.25 to 68.03 µM) depending on cell lineage. In HepG2 cells, the lowest IC50 value was exhibited by 3-acridin-9-ylmethyl-5-(4-piperidin-1-yl-benzylidene)-thiazolidine-2,4-dione (LPSF/AA36 – 7b; 46.95 µM). None of the synthesized compounds showed cytotoxic activity against normal cells (IC50 > 100 µM). The mechanism of death induction and cell cycle effects was also evaluated. Flow cytometric analysis revealed that the compounds LPSF/AA29 – 7a and LPSF/AA36 – 7b significantly increased the percentage of apoptotic cells and induced G2/M arrest in the cell cycle progression. Therefore, these new thiazacridine derivatives constitute promising antitumor agents whose cytotoxicity and selectivity properties indicate they have potential to contribute to or serve as a basis for the development of new cancer drugs in the future.

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Stimuli that induce a yeast heat shock gene fused to beta-galactosidase.

Molecular and Cellular Biology ◽

10.1128/mcb.4.12.2573 ◽

1984 ◽

Vol 4 (12) ◽

pp. 2573-2579 ◽

Cited By ~ 13

Author(s):

C Brazzell ◽

T D Ingolia

Keyword(s):

Heat Shock ◽

Heat Shock Gene ◽

Enzyme Assays ◽

Lacz Gene ◽

Directed Synthesis ◽

Shock Gene ◽

Chemical Stimuli ◽

Physical And Chemical ◽

Beta Galactosidase

Saccharomyces cerevisiae contain a multigene family related to the Drosophila heat shock gene hsp70. Two members of this family, YG100 and YG101, have been previously characterized (Ingolia et al., Mol. Cell. Biol. 2:1388-1398, 1982), and only YG100 was found to have elevated levels of transcription after heat shock. The yeast hsp70 genes contained on YG100 and YG101 were truncated and fused to the Escherichia coli lacZ gene contained on pMC1587 (Casadaban et al., Methods Enzymol. 100:283-308, 1983). The resulting plasmids directed synthesis of the beta-galactosidase gene as measured by in vitro enzyme assays and by colorimetric assays on plates. The expression level from the YG101 gene was constant under all the conditions tested, whereas expression driven by the YG100 gene could be induced over 50-fold. Other stimuli besides heat, including recovery from anoxia and high cell density, were found to strongly induce YG100 gene expression. Most physical and chemical stimuli tested, including UV irradiation, zymolyase treatment, and ethanol, did not stimulate expression of this heat shock gene.

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