scholarly journals Photocrosslinking and photopatterning of magneto-optical nanocomposite sol–gel thin film under deep-UV irradiation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Bidaud ◽  
D. Berling ◽  
D. Jamon ◽  
E. Gamet ◽  
S. Neveu ◽  
...  
Keyword(s):  
Uv Irradiation ◽  
Cobalt Ferrite ◽  
Sol Gel ◽  
Optical Devices ◽  
High Concentration ◽  
Nanocomposite Thin Films ◽  
Deep Uv ◽  
High Concentrations ◽  
193 Nm ◽  
The Impact

AbstractThis paper is aimed at investigating the process of photocrosslinking under Deep-UV irradiation of nanocomposite thin films doped with cobalt ferrite magnetic nanoparticles (MNPs). This material is composed of a hybrid sol–gel matrix in which MNP can be introduced with high concentrations up to 20 vol%. Deep-UV (193 nm) is not only interesting for high-resolution patterning but we also show an efficient photopolymerization pathway even in the presence of high concentration of MNPs. In this study, we demonstrate that the photocrosslinking is based on the free radical polymerization of the methacrylate functions of the hybrid precursor. This process is initiated by Titanium-oxo clusters. The impact of the nanoparticles on the photopolymerization kinetic and photopatterning is investigated. We finally show that the photosensitive nanocomposite is suitable to obtain micropatterns with sub-micron resolution, with a simple and versatile process, which opens many opportunities for fabrication of miniaturized magneto-optical devices for photonic applications.

scholarly journals Biphasic Effect of Pirfenidone on Angiogenesis

2022 ◽  
Vol 12 ◽  
Author(s):  
Donghao Gan ◽  
Wenxiang Cheng ◽  
Liqing Ke ◽  
Antonia RuJia Sun ◽  
Qingyun Jia ◽  
...  
Keyword(s):  
Vascular Endothelial Cells ◽  
Tube Formation ◽  
Endothelial Cell Migration ◽  
High Concentration ◽  
Low Concentrations ◽  
Biphasic Effect ◽  
High Concentrations ◽  
And Migration ◽  
The Impact

Pirfenidone (PFD), a synthetic arsenic compound, has been found to inhibit angiogenesis at high concentrations. However, the biphasic effects of different PFD concentrations on angiogenesis have not yet been elucidated, and the present study used an in vitro model to explore the mechanisms underlying this biphasic response. The effect of PFD on the initial angiogenesis of vascular endothelial cells was investigated through a Matrigel tube formation assay, and the impact of PFD on endothelial cell migration was evaluated through scratch and transwell migration experiments. Moreover, the expression of key migration cytokines, matrix metalloproteinase (MMP)-2 and MMP-9, was examined. Finally, the biphasic mechanism of PFD on angiogenesis was explored through cell signaling and apoptosis analyses. The results showed that 10–100 μM PFD has a significant and dose-dependent inhibitory effect on tube formation and migration, while 10 nM–1 μM PFD significantly promoted tube formation and migration, with 100 nM PFD having the strongest effect. Additionally, we found that a high concentration of PFD could significantly inhibit MMP-2 and MMP-9 expression, while low concentrations of PFD significantly promoted their expression. Finally, we found that high concentrations of PFD inhibited EA.hy926 cell tube formation by promoting apoptosis, while low concentrations of PFD promoted tube formation by increasing MMP-2 and MMP-9 protein expression predominantly via the EGFR/p-p38 pathway. Overall, PFD elicits a biphasic effect on angiogenesis through different mechanisms, could be used as a new potential drug for the treatment of vascular diseases.

Amide to Active Amine Conversion of Nylon by Deep UV Irradiation

1995 ◽  
Vol 397 ◽  
Author(s):  
Michael J. Kelley ◽  
Jeffrey D. Cohen ◽  
Carl Erkenbrecher ◽  
Sharon L. Haynie ◽  
Henry Kobsa ◽  
...  
Keyword(s):  
Microbial Activity ◽  
Ultraviolet Light ◽  
Polymer Chain ◽  
Uv Irradiation ◽  
Short Wavelength ◽  
Polymer Surfaces ◽  
Photochemical Processes ◽  
Deep Uv ◽  
193 Nm

ABSTRACTUltraviolet light having sufficiently short wavelength can drive photochemical processes at polymer surfaces. We find that irradiation at 193 nm, but not at 248 nm, results in conversion of amide groups at the nylon surface to amines, still bound in the polymer chain. These amines show anti-microbial activity [1].

scholarly journals Structural, Magnetic, Optical Properties and Photocatalytic Activity of Nanocrystalline Cobalt Ferrite Prepared by Three Different Methods

2021 ◽  
Author(s):  
S. S. Selima ◽  
W. A. Bayoumy ◽  
M. Khairy ◽  
M.A. Mousa
Keyword(s):  
Optical Properties ◽  
Cation Distribution ◽  
Cobalt Ferrite ◽  
Spinel Ferrite ◽  
Sol Gel ◽  
Mesoporous Structure ◽  
Particle Sizes ◽  
Preparation Route ◽  
Co Precipitation ◽  
The Impact

Abstract Cobalt ferrite (CoFe2O4) nanoparticles were synthesized through three different routes (chemical co-precipitation, ceramic, and sol-gel). The products were characterized by XRD, SEM, TEM, Raman spectroscopy, FTIR, photoluminescence (PL), BET, XPS, vibrating sample magnetometer (VSM). The X-ray analysis validates the spinel structure of the samples with particle sizes between 21 – 36 nm. XPS revealed the impact of the preparation route on cation distribution at the tetrahedral and octahedral sites in spinel ferrite lattice. All ferrite surfaces exhibit a mesoporous structure with a surface area between 25 – 99 m2/g. The results show that the prepared samples exhibit either ferromagnetic or super-paramagnetic behavior. The ferrite samples showed a photocatalytic performance under visible light. The present work demonstrates that each of the particle size and cation distribution is effective in controlling the structural, magnetic, and optical properties. The results obtained reveal that this kind of CoFe2O4 spinel ferrite nanoparticles has promising applications in magnetic designs and water treatment fields.

scholarly journals Light-responsive self-assembly of a cationic azobenzene surfactant at high concentration

Soft Matter ◽  
2020 ◽  
Vol 16 (40) ◽  
pp. 9183-9187
Author(s):  
Camille Blayo ◽  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Nikul Khunti ◽  
Nathan P. Cowieson ◽  
...  
Keyword(s):  
Long Range ◽  
Uv Irradiation ◽  
Self Assembly ◽  
Optical Anisotropy ◽  
Range Order ◽  
Long Range Order ◽  
High Concentration ◽  
Self Assembled ◽  
High Concentrations

A cationic azobenzene photosurfactant (AzoTAB) forms self-assembled structures with long-range order and optical anisotropy at high concentrations. These high-concentration mesophases are lost or disrupted with UV irradiation.

scholarly journals Binding and Functional Studies with the Growth Hormone Receptor Antagonist, B2036-PEG (Pegvisomant), Reveal Effects of Pegylation and Evidence That It Binds to a Receptor Dimer1

2001 ◽  
Vol 86 (4) ◽  
pp. 1716-1723 ◽  
Author(s):  
R. J. M. Ross ◽  
K. C. Leung ◽  
M. Maamra ◽  
W. Bennett ◽  
N. Doyle ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Growth Hormone Receptor ◽  
Membrane Binding ◽  
Membrane Receptor ◽  
High Concentration ◽  
Receptor Dimerization ◽  
Functional Studies ◽  
High Concentrations ◽  
The Impact ◽  
Receptor Dimer

GH actions are dependent on receptor dimerization. The GH receptor antagonist, B2036-PEG, has been developed for treating acromegaly. B2036 has mutations in site 1 to enhance receptor binding and in site 2 to block receptor dimerization. Pegylation (B2036-PEG) increases half-life and lowers immunogenicity, but high concentrations are required to control insulin-like growth factor-I levels. We examined antagonist structure and function and the impact of pegylation on biological efficacy. Unpegylated B2036 had a 4.5-fold greater affinity for GH binding protein (GHBP) than GH but similar affinity for membrane receptor. Pegylation substantially reduced membrane binding affinity and receptor antagonism, as assessed by a transcription assay, by 39- and 20-fold, respectively. GHBP reduced antagonist activity of unpegylated B2036 but did not effect antagonism by B2036-PEG. B2036 down-regulated receptors, and membrane binding sites doubled in the presence of dimerization-blocking antibodies, suggesting that B2036 binds to a receptor dimer. It is concluded that the high concentration requirement of B2036-PEG for clinical efficacy relates to pegylation, which decreases binding to membrane receptor but has the advantages of reduced clearance, immunogenicity, and interactions with GHBP. Our studies suggest that B2036 binds to a receptor dimer and induces internalization but not signaling.

scholarly journals Hybrid approaches coupling sol–gel and plasma for the deposition of oxide-based nanocomposite thin films: a review

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Maria Mitronika ◽  
Agnès Granier ◽  
Antoine Goullet ◽  
Mireille Richard-Plouet
Keyword(s):  
Thin Films ◽  
State Of The Art ◽  
Sol Gel ◽  
New Materials ◽  
Colloidal Solutions ◽  
Hybrid Approaches ◽  
Nanocomposite Thin Films ◽  
Deposition Processes ◽  
Physical And Chemical ◽  
The Impact

AbstractIn view of developing new materials with enhanced properties, such as nanocomposite (NC) thin films, special interest has been given in optimizing the deposition processes themselves. The latter, if well selected, could give the freedom to control the NCs synthesis and final properties. Attempting to overcome severe challenges observed when creating NC or oxide-based NC film, hybrid approaches combining injection of colloidal solutions and plasma processes have been proposed. This review focuses on oxide-based NCs, using as an example the TiO2 NPs and SiO2 matrix as NCs, while investigating their optical and dielectric properties. Additionally, this review presents the state-of-the-art in processes for the preparation of the NCs. The major categories of hybrid approaches coupling sol–gel and plasma processes are given. Finally, a comparative study among the published works is provided, aiming in highlighting the impact that each approach has on the physical and chemical characteristics of the produced NCs.

scholarly journals Effects of Ag Nanoparticles on Zinc Oxide Photocatalytic Performance

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 400
Author(s):  
Mouna Khiari ◽  
Mickaël Gilliot ◽  
Michaël Lejeune ◽  
Florica Lazar ◽  
Aomar Hadjadj
Keyword(s):  
Zinc Oxide ◽  
Spin Coating ◽  
Photocatalytic Performance ◽  
Sol Gel ◽  
Indigo Carmine ◽  
Heterogeneous Photocatalysis ◽  
Ag Nps ◽  
Nanocomposite Thin Films ◽  
Solar Resource ◽  
The Impact

We used a sol–gel spin coating technique to synthesize nanocomposite thin films based on zinc oxide (ZnO) loaded with silver nanoparticles (NPs). We tested these ZnO/Ag NP photocatalysts, with a thickness of about 100 nm, for the photodegradation of the indigo carmine dye solution. The study focused on the effects of Ag NPs on the ZnO matrix as well as the impact of their concentration on the photocatalytic performance of the nanocomposite. The study also highlighted the high stability of the photocatalytic performance of these nanocomposites. This work is a contribution in the search for non-toxic thin film photocatalysts that is usable under solar radiation for the treatment of contaminated wastewater. Innovation in the field of heterogeneous photocatalysis requires the use of solar resource with efficient results in terms of photocatalytic performance.

Formation Study of Nanocomposite Thin Films of Ferrite Dispersed in a Silica Matrix Prepared by sol-Gel Process

2003 ◽  
Vol 775 ◽  
Author(s):  
Nelcy D. S. Mohallem ◽  
Luciana M. Seara
Keyword(s):  
Thin Films ◽  
Saturation Magnetization ◽  
Cobalt Ferrite ◽  
Amorphous Matrix ◽  
Sol Gel ◽  
Dip Coating ◽  
Silica Matrix ◽  
Coating Process ◽  
Sol Gel Process ◽  
Nanocomposite Thin Films

AbstractMagnetic nanocomposite thin films formed by cobalt ferrite dispersed in silica matrix were prepared by sol-gel process using tetraethylorthosilicate (TEOS) as a precursor of silica, and metallic nitrates as precursors of the ferrite. The films were prepared with 5–50 wt. % ferrite contents and deposited on substrate using the dip-coating process. The films obtained were adherent, transparent, homogeneous and free of microcracks, with thickness between 30 and 500 nm. The films obtained presented crystalline CoFe2O4 phases dispersed in SiO2 amorphous matrix and saturation magnetization of approximately 9 emu/g considering the composite mass and 30 emu/g considering the ferrite mass.

scholarly journals Physiological and biochemical reactions of Hordeum vulgare seedlings to the action of silver nanoparticles

2015 ◽  
Vol 23 (2) ◽  
Author(s):  
N. O. Khromykh ◽  
L. V. Shupranova ◽  
Y. V. Lykholat ◽  
V. S. Bil’chuk ◽  
V. S. Fedenko ◽  
...  
Keyword(s):  
Hordeum Vulgare ◽  
Leaf Growth ◽  
Leaf Length ◽  
Fresh Weight ◽  
High Concentration ◽  
Hordeum Vulgare L ◽  
Antioxidant Defense Systems ◽  
High Concentrations ◽  
The Impact ◽  
Physiological And Biochemical

Morphometrical indexes, and spectrophotometrically measured protein and glutathione (GSH, GSSG) contents and activity of peroxidase (POD, EC 1.11.1.7), glutathione-reductase (GR, EC 1.6.4.2) and glutathione S-transferase (GST, EС 2.5.1.18) were examined in Hordeum vulgare L. seedlings after 0.01 and 0.1 mg/l AgNPs treatment during 24 h. We tested the hypothesis that the action of nanoparticles has a stressful effect on the physiological and biochemical processes of seedlings. Growth of roots was inhibited and fresh weight decreased by 29% and 21% under low and high concentrations respectively. Conversely, leaf growth was intensified, and leaf length (16% and 18%) and fresh weight (35% and 44%) increased at low and high concentrations respectively. POD activity in roots increased by 26% and 7%, and decreased in leaves to 57% and 81% of control at low and high concentrations respectively. GSH content changed insignificantly, but GSSG content increased in roots (2 and 2.5-fold) and in leaves (13% and 30%) at both AgNPs concentrations. GSH/GSSG-ratio decreased in roots (1.9 and 2.6-fold) and in leaves (1.1 and 1.3-fold) at low and high concentrations respectively. GR activity decreased at a concentration of 0.01 mg/l (7% in roots and 17% in leaves respectively) and increased at 0.1 mg/l (52% in roots and 6% in leaves). GST activity increased in leaves (52% and 78% at low and high concentrations) but decreased by 17% in roots under high concentration of nanosilver. Thus, the action of AgNPs on barley seedlings had a dose-dependent and organ-specific character. The various directions of changes in growth, metabolic processes and activity of antioxidant defense systems appear to be a stress response of barley seedlings to the impact of AgNPs, which underlines the necessity of detailed study of plant intracellular processes exposed to the action of nanomaterial. 

The Toxicity of Castor Beans and its Treatment with Doxycycline in Local Rabbits

2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Nael Mohammed Sarheed ◽  
Osamah Faisal Kokas ◽  
Doaa Abd Alabas Muhammed Ridh
Keyword(s):  
Castor Bean ◽  
The Body ◽  
Control Group ◽  
High Concentration ◽  
Biochemical Tests ◽  
Doxycycline Treatment ◽  
High Concentrations ◽  
Physiological Tests ◽  
Animal House ◽  
Physiological And Biochemical

The plant of castor is widely spread in the Iraqi land, and characterized with containing ricin toxin, which has a very serious effects, and because the seeds of this plant scattered in the agricultural soil and rivers water, which increases the exposure of humans and animals to these beans. Objective: This experiment was designed to study the effect of high concentration of castor bean powder in some physiological and biochemical parameters and changes in some tissues of the body, as well as trying to use doxycycline to reduce the effects of ingestion of these seeds. Materials and Methods: In the experiment, 24 local rabbits were raised and fed in the Animal House of the Faculty of Medicine / Al-Muthanna University, then divided into four groups and treated for three weeks (21 days), Control group: treated with normal saline solution (0.9) orally throughout the experiment, G1: was treated orally with a concentration of 25 mg / kg of castor bean powder daily during the experiment, G2 : orally treated 25 mg / kg of castor bean and 25 mg / kg of doxycycline, G3: orally treated 25 mg / kg of castor powder with 50 mg / kg of doxycycline daily throughout the trial period. Results: The results of the experiment showed significant changes (P less than 0.05) in all physiological and biochemical blood tests when compared with control group. There was a significant decrease in PCV, Hb, RBC, T.protein and body weights, while demonstrated a significant increase in WBC, Urea, Creatinine, ALT, AST and ALP, with distortions in liver and kidney of animals that treated with Castor beans. In contrast, the treatment with doxycycline and caster beans showed significant improvement reflected by a normal proportion in physiological tests and biochemical tests with improvement in the tissues when compared to control group. Conclusions: It can be concluded from this study that castor bean has high toxic and pathogenic effects that may be dangerous to the life of the organism. Therefore, it is advisable to be cautious of these pills and avoid exposure to them, also recommended to take high concentrations of doxycycline treatment when infected with castor bean poisoning.

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