The effect of UV light intensity on the kinetics of free-radical polymerization of 2-hydroxyethyl methacrylate (HEMA) triggered with the phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (BAPO) ...photoinitiator was investigated experimentally and theoretically. The temporal evolution of the conversion yield and polymerization rate was followed by Raman spectroscopy. The experimental data were treated with a kinetic model, which takes into account significant diffusion-controlled processes and termination pathways including bimolecular reaction and primary radical termination. This model showed very good agreement with the experiment in a large range of UV light intensities and shed light on the termination process. In particular, it was shown that the primary radical termination is dominant for relatively low light intensities below 1 mW/cm2, when the photoinitiator is weakly consumed during the polymerization process.
On 6 March 2015, Dawn arrived at Ceres to find a dark, desiccated surface punctuated by small, bright areas. Parts of Ceres' surface are heavily cratered, but the largest expected craters are absent. ...Ceres appears gravitationally relaxed at only the longest wavelengths, implying a mechanically strong lithosphere with a weaker deep interior. Ceres' dry exterior displays hydroxylated silicates, including ammoniated clays of endogenous origin. The possibility of abundant volatiles at depth is supported by geomorphologie features such as flat crater floors with pits, lobate flows of materials, and a singular mountain that appears to be an extrusive cryovolcanic dome. On one occasion, Ceres temporarily interacted with the solar wind, producing a bow shock accelerating electrons to energies of tens of kilovolts.
Here, we add the resonant γp → N*c¯c → J/ψp amplitudes to examine the effects of N*c¯c excitations on the cross sections of γp→J/ψp in the near threshold energy region covered by the recent ...experiments at Jefferson Lab. The N*c¯c → MB transition matrix elements are determined from the partial decay widths predicted by the considered meson-baryon coupled-channel models of N*c¯c.
IMPORTANCE: Early onset of myopia is associated with high myopia later in life, and myopia is irreversible once developed. OBJECTIVE: To evaluate the efficacy of low-concentration atropine eyedrops ...at 0.05% and 0.01% concentration for delaying the onset of myopia. DESIGN, SETTING, AND PARTICIPANTS: This randomized, placebo-controlled, double-masked trial conducted at the Chinese University of Hong Kong Eye Centre enrolled 474 nonmyopic children aged 4 through 9 years with cycloplegic spherical equivalent between +1.00 D to 0.00 D and astigmatism less than −1.00 D. The first recruited participant started treatment on July 11, 2017, and the last participant was enrolled on June 4, 2020; the date of the final follow-up session was June 4, 2022. INTERVENTIONS: Participants were assigned at random to the 0.05% atropine (n = 160), 0.01% atropine (n = 159), and placebo (n = 155) groups and had eyedrops applied once nightly in both eyes over 2 years. MAIN OUTCOMES AND MEASURES: The primary outcomes were the 2-year cumulative incidence rate of myopia (cycloplegic spherical equivalent of at least −0.50 D in either eye) and the percentage of participants with fast myopic shift (spherical equivalent myopic shift of at least 1.00 D). RESULTS: Of the 474 randomized patients (mean age, 6.8 years; 50% female), 353 (74.5%) completed the trial. The 2-year cumulative incidence of myopia in the 0.05% atropine, 0.01% atropine, and placebo groups were 28.4% (33/116), 45.9% (56/122), and 53.0% (61/115), respectively, and the percentages of participants with fast myopic shift at 2 years were 25.0%, 45.1%, and 53.9%. Compared with the placebo group, the 0.05% atropine group had significantly lower 2-year cumulative myopia incidence (difference, 24.6% 95% CI, 12.0%-36.4%) and percentage of patients with fast myopic shift (difference, 28.9% 95% CI, 16.5%-40.5%). Compared with the 0.01% atropine group, the 0.05% atropine group had significantly lower 2-year cumulative myopia incidence (difference, 17.5% 95% CI, 5.2%-29.2%) and percentage of patients with fast myopic shift (difference, 20.1% 95% CI, 8.0%-31.6%). The 0.01% atropine and placebo groups were not significantly different in 2-year cumulative myopia incidence or percentage of patients with fast myopic shift. Photophobia was the most common adverse event and was reported by 12.9% of participants in the 0.05% atropine group, 18.9% in the 0.01% atropine group, and 12.2% in the placebo group in the second year. CONCLUSIONS AND RELEVANCE: Among children aged 4 to 9 years without myopia, nightly use of 0.05% atropine eyedrops compared with placebo resulted in a significantly lower incidence of myopia and lower percentage of participants with fast myopic shift at 2 years. There was no significant difference between 0.01% atropine and placebo. Further research is needed to replicate the findings, to understand whether this represents a delay or prevention of myopia, and to assess longer-term safety. TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR-IPR-15006883
Hybrid materials, based on inorganic nanoblocks incorporated into polymer networks, are an important class of functional materials. Although the kinetic of the free-radical polymerization of neat ...polymers has been studied for many years, both theoretically and experimentally, studies devoted to the polymerization kinetics of nanocomposite materials are rare. In this study, photosensitive hybrids formed using poly(2-hydroxyethyl methacrylate) (pHEMA) and titanium dioxide (TiO
2
) nanoparticles functionalized with polymerizable ligands were considered. Their bulk UV-induced free-radical photopolymerization was investigated to evaluate the potential of pHEMA/TiO
2
hybrids as a material of choice for the fabrication of micro-optical devices. The influence of the nanoparticle concentration and UV intensity on the polymerization kinetics, probed in situ by Raman spectroscopy, is discussed. A decrease in the initiation rate was observed, which was attributed to the UV absorption of TiO
2
nanoparticles. This leads to a decrease in the propagation rate with an increase in nanoparticle concentration. Furthermore, a decrease in the maximum C=C conversion yield was observed when the nanoparticle concentration was increased. This was attributed to the formation of microgel regions around the nanoparticles, which prevented the polymer chains from bonding with surface ligands. Despite the lower conversion yield, we demonstrated the fabrication of one-dimension (1D) photoactive microstructures in pHEMA/TiO
2
hybrids. The photochromic efficiency of the obtained structure was evaluated based on the reduction in silver (Ag) ions under UV irradiation. The results show that pHEMA/TiO
2
hybrids can be considered as a prospective material for the realization of photosensitive microelements.
Disease-associated genetic variants that lie in non-coding regions found by genome-wide association studies are thought to alter the functionality of transcription regulatory elements and target gene ...expression. To uncover causal genetic variants, variant regulatory elements and their target genes, here we cross-reference human transcriptomic, epigenomic and chromatin conformation datasets. Of 104 genetic variant regions associated with atrial fibrillation candidate target genes are prioritized. We optimize EMERGE enhancer prediction and use accessible chromatin profiles of human atrial cardiomyocytes to more accurately predict cardiac regulatory elements and identify hundreds of sub-threshold variants that co-localize with regulatory elements. Removal of mouse homologues of atrial fibrillation-associated regions in vivo uncovers a distal regulatory region involved in Gja1 (Cx43) expression. Our analyses provide a shortlist of genes likely affected by atrial fibrillation-associated variants and provide variant regulatory elements in each region that link genetic variation and target gene regulation, helping to focus future investigations.
Oral squamous cell carcinoma (OSCC) is among the most commonly diagnosed malignancies in the world. Patients with OSCC often develop treatment resistance, resulting in a poor prognosis. Mounting ...evidence indicates that interactions between cancerous cells and other components of the tumor microenvironment (TME) determine their response to treatment. Herein, we examined the role of cancer stem cell-derived extracellular vesicles (CSC_EVs) generated from CAL27 and SCC-15 OSCC cells in the development of cisplatin (CDDP) resistance. We demonstrated that CSC_EVs enhance CDDP resistance, clonogenicity, and the tumorsphere formation potential of OSCC cells. Our bioinformatics analyses revealed that OSCC_EVs are enriched with microRNA (miR)-21-5p and are associated with increased metastasis, stemness, chemoresistance, and poor survival in patients with OSCC. Mechanistically, enhanced activity of CSC_EVs was positively correlated with upregulated β-catenin, phosphatidylinositol-3 kinase (PI3K), signal transducer and activator of transcription 3 (STAT3), mammalian target of rapamycin (mTOR), and transforming growth factor (TGF)-β1 messenger (m)RNA and protein expression levels. CSC_EVs also conferred a cancer-associated fibroblast (CAF) phenotype on normal gingival fibroblasts (NGFs), with the resultant CAFs enhancing the oncogenicity of OSCC cells. Interestingly, treatment with ovatodiolide (OV), the bioactive component of
, suppressed OSCC tumorigenesis by reducing the cargo content of EVs derived from CSCs, suppressing self-renewal, and inhibiting the NGF-CAF transformation by disrupting EV-TME interactions. Moreover, by suppressing miR-21-5p, STAT3, and mTOR expressions in CSC_EVs, OV re-sensitized CSCs to CDDP and suppressed OSCC tumorigenesis. In vivo, treatment with OV alone or in combination with CDDP significantly reduced the tumor sphere-forming ability and decreased EV cargos containing mTOR, PI3K, STAT3, β-catenin, and miR-21-5p. In summary, our findings provide further strong evidence of OV's therapeutic effect in OSCC.
Schwertmannite is a poorly crystalline Fe(III) hydroxide, which always shows high sorption capacities to pollutants. In this study, schwertmannite synthesized from the Fe
3+
hydrolyzation method ...showed a hedgehog-like shape, with a specific surface area of 325.5 m
2
g
−1
, which was much higher than that of the sphere-like schwertmannite synthesized from the Fe
2+
oxidation method, with a specific surface area of 48.2 m
2
g
−1
. The former was then used to evaluate its sorption performance to As(V) and As(III). Sorption of As(V) and As(III) could reach equilibrium in 200 min, and the maximum sorption capacities of As(V) and As(III) were 182.86 and 45.50 mg g
−1
at pH 3.0, respectively, and 143.25 and 217.85 mg g
−1
at pH 7.0, respectively. Sorption capacity was dependent on pH and more As(V) adsorbed on schwertmannite at lower pH, while As(III) sorption increased with the increase of pH. Our results also indicated that the presence of sulfate reduced the sorption of As(V) from 85.4 to 67.6 mg g
−1
as sulfate concentration increased from 0.2 to 6 g L
−1
, while such an effect was not apparent in As(III) sorption. Nitrate and chloride did not show significant interference on the sorption of both As(V) and As(III). Schwertmannite showed better repeated uses in the removal of As(V) and As(III) after seven repeated using cycles with removal percentages of 95.3 % at pH 3.0 and 63.9 % at pH 7.0 to As(V), and 31.0 % at pH 3.0 and 81.6 % at pH 7.0 to As(III).
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