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Skin surface is constantly exposed to environmental and secreted stressors such as UV, air pollution and peroxidized sebum. The current study aims to use reconstructed human skin equivalents to demonstrate topical stressor‐induced hyperpigmentation and evaluate bioactives’ potential protective effect. Given that polycyclic aromatic hydrocarbons are representative airborne particle‐bound organic compounds with known relevance to pigmentation pathways, benzo(a)pyrene was selected as surrogate environmental toxin. On the other hand, squalene monohydroperoxides are well‐characterized sebum peroxidation product under UV and pollutant exposure, thus are used as another representative skin stressor. With 3‐day continuous exposure, 30 pmol/cm2 of benzo(a)pyrene and 3.4 nmol/cm2 of squalene monohydroperoxides induced significant viability loss, inflammatory response, and approximately 10 shades of pigmentation increase in pigmented living skin equivalents. At the same time, pretreatment and co‐treatment with 12‐hydroxystearic acid (12‐HSA, 20 μmol/L) or niacinamide (5 mmol/L) ameliorated such stressor‐induced consequences. Niacinamide was particularly effective against benzo(a)pyrene damage, probably as a substrate for important NAD+ dependent detoxification pathways, while 12‐HSA was potent against squalene monohydroperoxides through barrier enhancing, anti‐inflammatory, and anti‐oxidative mechanisms. In summary, topical stressor‐induced hyperpigmentation was achieved in vitro, with known bioactives showing protective benefits.

A simple, rapid and visual mesoporous silica (MSNs)-electrochemiluminescence (ECL) sensor was developed for on-site monitoring of Cat.

Qiu et al.: Effects of Resveratrol on Parkinson's Disease We herein aimed to evaluate the neuroprotective effects of resveratrol on a mouse model of Parkinson's disease and to explore whether the Wnt/beta-catenin signaling pathway was involved. Thirty male C57 black 6 mice were randomly divided into a control group, a model group (1-methyl-4-phenyl-1,2,3,6tetrahydropyridine) and a treatment group (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine resveratrol) (n=10). The model and treatment groups were intraperitoneally injected with 1-methyl-4-phenyl-1,2,3,6tetrahydropyridine (30 mg/kg in normal saline) to induce Parkinson's disease. Then the treatment group was administered with resveratrol (20 mg/kg in 0.5 % sodium carboxymethylcellulose solution) on the 1 st d of modeling. The motor coordination ability was studied by the pole climbing test. Astrocyte and microglia activations in the substantia nigra pars compacta were observed by immunohistochemical staining. 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced striatum dopamine release was measured by high performance liquid chromatography and dopamine transporter level was detected with Western blot. SH-SY5Y cell viability and dependence on the Wnt/beta-catenin signaling pathway were assessed by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide assay and Western blot, respectively. Resveratrol relieved the motor dysfunction, death of dopaminergic neurons, activation of astrocytes and microglia, as well as reduction of striatum dopamine content induced by neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in vitro. It also alleviated the damage of SH-SY5Y cells induced by 1-methyl-4-phenylpyridinium. Resveratrol increased the levels of proteins from the Wnt/beta-catenin signaling pathway in the mouse model of Parkinson's disease and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridinetreated SH-Y5Y cells. Resveratrol exerted neuroprotective effects on the Parkinson's disease model predominantly by regulating the Wnt/beta-catenin signaling pathway.

Dielectric metasurfaces supporting Mie resonances can allow significantly boosted and tailored nonlinear light–matter interactions at the nanoscale. However, nonlinear dielectric metasurfaces typically only have odd‐order nonlinearities, unless resorting to material systems such as GaAs, GaP, or LiNbO3, each with unique challenges in device fabrication and integration. As the most widely adopted constituent material of metasurfaces, silicon (Si) does not possess an intrinsic second‐order nonlinear susceptibility. Herein, second‐harmonic generation (SHG) in a Si metasurface strained by a silicon nitride (SiN x ) cladding layer is demonstrated. Utilizing the stress caused by the SiN x layer to break the inversion symmetry of the bulk Si crystal, greatly enhanced SHG in the strained Si metasurface compared with that from an unpatterned Si film with the SiN x cladding layer, with an experimentally measured conversion efficiency as high as 4.2 × 10−5 W−1, is observed. Experiments are further performed and it is concluded that the enhanced SHG is most likely due to the applied stress instead of charged defects in the SiN x cladding. This work opens a new route to realizing dielectric metasurfaces with second‐order nonlinearity in a complementary metal–oxide–semiconductor (CMOS)‐compatible platform.