A self-assembled DNA nanostructure as an efficient signal amplifier was introduced to create a simple and label-free quartz crystal microbalance with dissipation monitoring (QCM-D) biosensing platform for highly sensitive and selective detection of nucleic acids.

A forward-illumination light-extinction (FILE) soot volume fraction measurement technique was developed and tested. By using a camera and a point light source in front of the flame and a diffuser behind the flame, with this technique one can achieve a two-dimensional soot concentration measurement with only one window when one is studying confined combustion. The line-of-sight quantitative soot volume fraction is obtained by calculation of the reflected light intensity with or without the presence of soot cloud. Verification of this technique was accomplished by measurement of an axisymmetric ethylene diffusion flame. The field distribution obtained by Abel inversion is presented and matched well with previous point measurements. The FILE technique has high time resolution when a high-speed camera and a copper vapor laser are adopted. All these advantages of FILE make it suitable for line-of-sight integrated, two-dimensional soot distribution of transient combustion, e.g., in the case of in-cylinder Diesel combustion.

No abstract

Quercetin has been preliminarily proven to serve as a potential agent for the treatment of osteoarthritis (OA). However, its effects and potential mechanisms on the pathological process of OA are not very clear. This study aimed to study the protective effect of quercetin on OA. Lipopolysaccharide (LPS)-treated chondrocytes (C28/I2 cell) and anterior cruciate ligament transection with partial medial meniscectomy-treated Wistar rats were used as models of OA in vitro and in vivo. Cell counting kit-8 (CCK-8 kit), flow cytometry, enzyme-linked immunosorbent assay (ELISA) kit, western blot, dichlorodihydrofluorescein diacetate (DCFH-DA) kit, thiobarbituric acid (TBA) test, toluidine blue staining, Hematoxylin eosin (HE) staining and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) staining were used to evaluate cell viability, cell apoptosis, inflammatory cytokines level, protein expression, reactive oxygen species (ROS) level, malondialdehyde (MDA) content, morphological changes, and chondrocyte apoptosis of cartilage, respectively. Results showed that quercetin could reduce LPS-induced C28/I2 cell apoptosis, extracellular matrix (ECM) degradation, and cell pyroptosis, and overexpression of nucleotide-binding domain and leucine-rich-repeatcontaining (NLR) family, pyrin domain-containing 3 (NLRP3) revealed that quercetin reduced chondrocyte apoptosis and ECM degradation by inhibiting NLRP3-mediated pyroptosis. Furthermore, quercetin could reduce chondrocyte apoptosis and ECM degradation, and inhibit NLRP3-mediated pyroptosis through blocking oxidative stress. It was further confirmed in the rat OA model that quercetin alleviated OA by blocking oxidative stress, reduces chondrocyte pyroptosis, apoptosis, and ECM degradation. In conclusion, quercetin inhibited OA via blocking oxidative stress-induced chondrocyte pyroptosis in models of OA in vitro and in vivo.

Retinitis pigmentosa (RP) is a group of inherited neurodegenerative diseases characterized by the loss of photoreceptor cells through apoptosis. N-methyl-N-nitrosourea (MNU) is an alkylating toxicant that induces photoreceptor cell death resembling hereditary RP. This study aimed to investigate the role of nuclear factor κB (NF-κB) in MNU-induced photoreceptor degeneration. Adult rats received a single intraperitoneal injection of MNU (60 mg/kg bodyweight). Hematoxylin and eosin staining demonstrated progressive outer nuclear layer (ONL) loss after MNU treatment. Transmission electron microscopy revealed nuclear pyknosis, chromatin margination in the photoreceptors, increased secondary lysosomes, and lobulated retinal-pigmented epithelial cells in MNU-treated rats. Numerous photoreceptor cells in the ONL showed positive TUNEL staining and apoptosis rate peaked at 24 hours. Enhanced depth imaging spectral-domain optical coherence tomography showed ONL thinning and decreased choroid thickness. Electroretinograms showed decreased A wave amplitude that predominated in scotopic conditions. Western blot analysis showed that nuclear IκBα level increased, whereas nuclear NF-κB p65 decreased significantly in the retinas of MNU-treated rats. These findings indicate that MNU leads to selective photoreceptor degradation, and this is associated with the inhibition of NF-κB activation.