Interpenetrating poly(urethane-urea)–polydimethylsiloxane networks designed as active elements in electromechanical transducers

A poly(urethane-urea-siloxane) was prepared in a two-step procedure involving the synthesis of a bis-isocyanate prepolymer on the basis of 4,4′-diphenylmethane diisocyanate, a polyether glycol and dimethylol propionic acid, and its extension by reacting with 1,3-bis(3-aminopropyl)tetramethyldisiloxane. The resulted polymer was used in different percentages to prepare three series of interpenetrating networks (IPNs) with polydimethylsiloxane-α,ω-diols with molecular masses, Mn, of 70000, 230000 and 370000 g mol−1. A polydimethylsiloxane–polyethyleneoxide graft copolymer was added as a compatibilizing agent. The IPN precursors were mixed in solution and processed as films. During solvent evaporation, the chemical crosslinking of the polydimethylsiloxane-α,ω-diols occurs with tetraethyl orthosilicate in the presence of dibutyltin dilaurate, while in the case of poly(urethane-urea-siloxane) only physical crosslinking by hydrogen bonds is expected to occur. The morphology and thermal transitions of the resulted networks were examined by scanning electron microscopy, differential scanning calorimetry with dynamic mechanical analysis. The mechanical and dielectric characteristics (dielectric permittivity, loss, strength) of the aged films were studied. Their responsiveness to an external stimulus in the form of an increasing electric field was assessed by electromechanical measurements and expressed as lateral strain. The results were critically analyzed with respect to each other as a correlation with their composition and compared with those obtained for three common commercially available dielectric elastomers

Effects of Zeaxanthin on Growth and Invasion of Human Uveal Melanoma in Nude Mouse Model

Uveal melanoma cells were inoculated into the choroid of nude mice and treated with or without intraocular injection of zeaxanthin. After 21 days, mice were sacrificed and the eyes enucleated. Histopathological analysis was performed in hematoxylin and eosin stained frozen sections. Melanoma developed rapidly in the control group (without treatment of zeaxanthin). Tumor-bearing eye mass and tumor mass in the control group were significantly greater than those in zeaxanthin treated group. Melanoma in the controlled eyes occupied a large part of the eye, was epithelioid in morphology, and was with numerous mitotic figures. Scleral perforation and extraocular extension were observed in half of the eyes. Melanomas in zeaxanthin treated eyes were significantly smaller with many necrosis and apoptosis areas and no extraocular extension could be found. Quantitative image analysis revealed that the tumor size was reduced by 56% in eyes treated with low dosages of zeaxanthin and 92% in eyes treatment with high dosages of zeaxanthin, as compared to the controls. This study demonstrated that zeaxanthin significantly inhibits the growth and invasion of human uveal melanoma in nude mice, suggesting that zeaxanthin may be a promising agent to be explored for the prevention and treatment of uveal melanoma

Bentonite as an active natural filler for silicone leading to piezoelectric-like response material

Raw sodium bentonite (Bent) without preliminary treatments is incorporated as a filler in a silicone matrix, from 5 to 100 parts per hundred (pph), by weight, by simple mixing in solution. The mixtures are processed as films and stabilized by condensation crosslinking at room temperature. Besides being environmentally safe and non-toxic, bentonite is 30 times cheaper than polydimethylsiloxane (PDMS), so the cost price of composites can be reduced by over 40%. Studies on the effects of bentonite addition as filler on the properties of composites reveal that thermal stability is not significantly affected, while an increase in the amount of inorganic residue with an increase of Bent content is recorded. More importantly, the mechanical and dielectric properties are significantly influenced by the Bent content in the PDMS matrix. The Young's modulus increases, while the elongation decreases, indicating a stiffening of the material and a decrease in its elasticity as the Bent load increases. Most notably, the dielectric permittivity increases up to more than five times at 103 Hz by adding 100 pph Bent, while the dielectric losses remain acceptable, especially at high frequencies for all composites. Furthermore, the study of composite films through Piezoresponse Force Microscopy and piezoelectric testing system reveals an outstanding piezoelectric-like response for composites with a high Bent content. The wideangle X-ray diffraction indicates an increase of the crystalline fraction - the main factor that influences the apparent piezoelectric coefficient - with increasing the Bent loa

Effects of Lutein on Hyperosmoticity-Induced Upregulation of IL-6 in Cultured Corneal Epithelial Cells and Its Relevant Signal Pathways

Dry eye is a common disorder characterized by deficiency of tear. Hyperosmoticity of tear stimulates inflammation and damage of ocular surface tissues and plays an essential role in the pathogenesis of dry eye. Cultured human corneal epithelial (CE) cells were used for the study of effects of lutein and hyperosmoticity on the secretion of IL-6 by CE cells. Cell viability of CE cells was not affected by lutein at 1–10 μM as determined by MTT assay. Hyperosmoticity significantly elevated the secretion of IL-6 by CE cells as measured by ELISA analysis. The constitutive secretion of IL-6 was not affected by lutein. Lutein significantly and dose-dependently inhibited hyperosmoticity-induced secretion of IL-6. Phosphorylated- (p)- p38 MAPK, p-JNK levels in cell lysates and NF-κB levels in cell nuclear extracts were increased by being exposed to hyperosmotic medium. JNK, p38, and NF-κB inhibitors decreased hyperosmoticity-induced secretion of IL-6. Lutein significantly inhibited hyperosmoticity-induced elevation of NF-κB, p38, and p-JNK levels. We demonstrated that lutein inhibited hyperosmoticity-induced secretion of IL-6 in CE cells through the deactivation of p38, JNK, and NF-κB pathways. Lutein may be a promising agent to be explored for the treatment of dry eye

Androgen Activity Is Associated With PD-L1 Downregulation in Thyroid Cancer

Thyroid cancer is the most prevalent endocrine malignancy in the United States with greater than 53,000 new cases in 2020. There is a significant gender disparity in disease incidence as well, with women developing thyroid cancer three times more often than men; however, the underlying cause of this disparity is poorly understood. Using RNA-sequencing, we profiled the immune landscape of papillary thyroid cancer (PTC) and identified a significant inverse correlation between androgen receptor (AR) levels and the immune checkpoint molecule PD-L1. The expression of PD-L1 was then measured in an androgen responsive-thyroid cancer cell line. Dihydrotestosterone (DHT) treatment resulted in significant reduction in surface PD-L1 expression in a time and dose-dependent manner. To determine if androgen-mediated PD-L1 downregulation was AR-dependent, we treated cells with flutamide, a selective AR antagonist, and prior to DHT treatment to pharmacologically inhibit AR-induced signaling. This resulted in a \u3e 90% restoration of cell surface PD-L1 expression, suggesting a potential role for AR activity in PD-L1 regulation. Investigation into the AR binding sites showed AR activation impacts NF-kB signaling by increasing IkBalpha and by possibly preventing NF-kB translocation into the nucleus, reducing PD-L1 promoter activation. This study provides evidence of sex-hormone mediated regulation of immune checkpoint molecules in vitro with potential ramification for immunotherapies

RECOVERY OF HAND ARTHRITIS BY PHYSICAL THERAPY

Rheumatoid arthritis has a chronic progressive evolution, requiring early and lasting intensive treatment. The disease predominates in women, being more frequent onset between 30-40ani. For this study, we had the three subjects diagnosed with rheumatoid arthritis with various forms of evolution. Each patient received an individualized physical therapy program. After the treatment was found an improvement of symptoms of rheumatoid arthritis: as the treatment was applied at an earlier stage of disease, the results were better

Conjunctival myxoma: A case report with unique high frequency ultrasound (UBM) findings

A 39-year-old female presented with a painless yellow-pink tumor on her right eye. High-frequency ultrasound imaging revealed an epibulbar lesion with homogenous low internal reflectivity and no evidence of intraocular invasion. The patient underwent excisional biopsy leading to a pathology diagnosis of myxoma. Additional surgical margins as well as adjuvant cryotherapy margins were followed by extensive conjunctival repair. Herein, we report on a conjunctival myxoma with unique ultrasonographic findings

Nanomaterials Developed by Processing Iron Coordination Compounds for Biomedical Application

The iron oxides, widespread in nature, are used in numerous applications in practice due to their well-known properties. These properties can be modified by size lowering at nanoscale. Some applications, such as biomedical, require a rigorous selection of nanoparticles by size, shape, and surface functionality. In other applications, such as catalysis or magnetism, the composition (generally mixed oxides) and morphology of the nanoparticles are of high importance. The preparation of iron oxide nanoparticles (IONPs) is a complex process whose control raises a number of issues. The first challenge is finding the optimal experimental conditions, which would lead to the preparation of monodisperse nanoparticles. Another issue is the selection or setting a reproducible and clean manufacturing process without a need of complex purification. Even though at the moment several methods for preparing IONPs are known, there are still concerns in the scientific world to further improve existing methods or create new protocols. Therefore, the establishment of optimal methods for preparing IONPs with predetermined structural, dimensional, and morphological characteristics is an important task of scientists. Most of the methods reported in literature for the preparation of IONPs use proper metal salts as precursors. Recently, the use of the organometallic and coordination compounds of iron as precursors for IONPs has emerged as an alternative for a better control of these. Here, achievements reported in the literature in this direction are reviewed and critically analysed in relation to the conventional method based on iron salts

Papillary conjunctivitis presenting months after permanent eyebrow tattooing

Purpose: To present a case of tattoo side effects not limited to the tattoo site and rise an alarm regarding using non-FDA-approved products. Observations: A 30-year-old female presented with bilateral ocular pain, dryness, and itching. The ocular exam showed bilateral injection and edema of the superior palpebral and bulbar conjunctiva. Several 1–2 mm dark pigmented lesions and papillae coursing along the upper palpebral conjunctival lid margin and 5 mm above the margin were found in both eyes. The ocular surface was dry with diffuse superficial punctate keratitis. The biopsy report showed granular foreign material in the dermis. SOX-10 and MART-1 immunostaining highlighted melanocyte distribution and the sample was diagnosed as exogenous pigment consistent with tattoo ink by the pathologist. On further investigation following the pathology report, the patient stated that she got bilateral permanent eyebrow tattoos 4 months before presentation in a country other than the United States, and she was not aware about the standards of the ink used, nor the certification of the person performing the tattoo. The patient denied any type of tattoo or manipulation on the eyes or orbit, including sclera or conjunctivae. Conclusions: Importance: The complications of periorbital tattooing are not limited to the point tattoo location and can potentially spread to the nearby segments. It is notable that there is no FDA approved tattoo ink available, even with a certified tattoo artist performing the tattoo, the risks of inflammation, infection, and other side effects are still present