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The Belinfante spin momentum (BSM) is a fundamental yet enigmatic quantity of electromagnetic fields. It vanishes from the global momentum of the field, but can be detected locally, manifesting itself as an optical force on small particles. Hitherto, however, the BSM force is a concept well established only within the dipole approximation, and there is no explicit experimental evidence for its action on multipoles. Here, a theoretical model for multipolar BSM forces, exerted on generic Mie particles supporting multipoles of arbitrary order, is developed. This multipolar mechanical action is observed experimentally from a structured light field, which suppresses the effect of spin–orbit coupling. It can also selectively enhance the multipolar BSM forces, while restraining the dipolar component on a probe particle (Au sphere). These results constitute a distinct chapter in the physics of high‐order interactions in light–matter systems and can facilitate additional progress in optomechanics, optical manipulation, and Mie‐tronics. [ABSTRACT FROM AUTHOR]

Influenza A(H3N8) viruses first emerged in humans in 2022, but their public health risk has not been evaluated. Here, we systematically investigated the biological features of avian and human isolated H3N8 viruses. The human‐origin H3N8 viruses exhibited dual receptor binding profiles but avian‐origin H3N8 viruses bound to avian type (sialic acid α2, 3) receptors only. All H3N8 viruses were sensitive to the antiviral drug oseltamivir. Although H3N8 viruses showed lower virulence than the 2009 pandemic H1N1 (09pdmH1N1) viruses, they induced comparable infectivity in mice. More importantly, the human population is naïve to H3N8 virus infection and current seasonal vaccination is not protective. Therefore, the threat of influenza A(H3N8) viruses should not be underestimated. Any variations should be monitored closely and their effect should be studied in time for the pandemic potential preparedness purpose. [ABSTRACT FROM AUTHOR]

Prolonged skin exposure to ultraviolet radiation can lead to development of several acute and chronic diseases, with UVA exposure considered a primary cause of dermal photodamage. We prepared a wild ginseng adventitious root extract (ARE) that could alleviate UVA irradiation‐induced NIH‐3T3 cell viability decline. After employing a series of purification methods to isolate main active components of ARE, adventitious root protein mixture (ARP) was identified then tested for protective effects against UVA irradiation‐induced NIH‐3T3 cell damage. The results showed that ARP treatment significantly reduced UVA‐induced cell viability decline and confirmed that the active constituent of ARP was the protein, since proteolytic hydrolysis and heat treatment each eliminated ARP protective activity. Moreover, ARP treatment markedly inhibited UVA‐induced apoptosis, cell cycle arrest and DNA fragmentation, while also significantly reversing UVA effects (elevated Bax levels, reduced Bcl‐2 expression) by reducing Bax levels and increasing Bcl‐2 expression. Mechanistically, ARP promoted Akt phosphorylation regardless of UVA exposure, thus confirming ARP resistance to inactivation by UVA light. Notably, in the presence of Akt inhibitor SC0227, ARP could no longer counteract UVA‐induced cell viability decline and DNA fragmentation. Additionally, our results demonstrated that ARP treatment protected UVA‐irradiated NIH‐3T3 cells by preventing UVA‐induced reduction of collagen‐I expression. Taken together, these results suggest that ARP treatment of NIH‐3T3 cells effectively mitigated UVA‐induced cell viability decline by activating intracellular Akt to reduce UVA‐induced DNA damage, leading to reduced rates of apoptosis and cell cycle arrest after UVA exposure and restoring collagen expression to normal levels. [ABSTRACT FROM AUTHOR]

The visual perception of a moving target is not always true. Wheels turning rapidly, for instance, may look like rotating inversely. This phenomenon is known as the wagon‐wheel effect (WWE) and it is caused by the undersampling of visual information. Here, an analogous manifestation of the WWE concept is described in the scenario of light–matter interactions, by showing that the dynamic response of a particle, to an optical trap scanned at different rates, can be diametrically opposed. Further, such behaviors are modulated by the particle dimensions, which can be exploited for particle size selection. The results uncover a distinct paradigm of nontrivial optical manipulation and expand the bidirectional optical sorting range of dielectric particles to the sub‐200 nm scale. [ABSTRACT FROM AUTHOR]

The intensity gradient of light represents the most important property for optical tweezers to manipulate small particles, which is known to produce a conservative optical force that is either attractive or repulsive. Here, it is shown that Kerker interference, the interplay between electric and magnetic dipoles induced in nanoparticles, permits the intensity gradient to exert a nonconservative optical force, in the case of a standard optical trap created with linearly or elliptically polarized Gaussian beams. The Kerker‐type intensity‐gradient force has an "anisotropic" directionality, and it tends to repel particles away from the beam axis. Such repulsive effects can greatly sensitize the particle trapping behavior of optical tweezers to the particle size. Utilizing these peculiar properties, all‐optical sorting of Si nanoparticles is theoretically demonstrated, with tunable size‐selection criterion and accuracy. [ABSTRACT FROM AUTHOR]

UVA can penetrate dermis and cause functional damage of dermal fibroblasts leading photoaging. Ginseng is a widely used traditional Chinese medicine for skin aging. However, its effects on skin photoaging induced by UVA are not clear. In this study, we isolated ginseng proteins (GP), with molecular weights of 27 kDa and 13 kDa, and found that they alleviated the inhibitory effects of UVA on cell viability and increased percentage of NIH‐3T3 fibroblasts in the S phase of cells cycle. GP also improved cell contraction ability, increased the expression and secretion of CoL‐I, similar to MAPK phosphorylation inhibitors and reduced expression and secretion of MMP‐1, MMP‐2 and MMP‐9 as well as the enzyme activities of MMP‐2 and MMP‐9. They reduced ROS content, DNA damage and 8‐OHdG content, as well as the protein expression of p53, p21 and p16. The levels of p‐ERK, p‐p38 and p‐JNK, p‐c‐Fos and p‐c‐Jun proteins were decreased by GP. Inactivated GP did not inhibit the cellular activity and expression and secretion of CoL‐I irradiated by UVA. The results showed that GP can improve cell viability and contractile function by inhibiting DNA damage and collagen degradation to inhibit the photoaging effects of skin dermal cells caused by UVA. [ABSTRACT FROM AUTHOR]

Intensity-Gradient Force: Kerker-Type Intensity-Gradient Force of Light (Laser Photonics Rev. 14(4)/2020) In article number 1900265 by Yao Zhang and co-workers, a nontrivial optical intensity-gradient force is uncovered in conventional optical tweezers set-ups. Its non-conservative and anisotropic properties are in sharp contrast to the classical widespread picture of optical intensity-gradient forces. [Extracted from the article]

The single‐cell screening has attracted great attentions in advanced biomedicine and tissue biology, especially for the early disease diagnosis and treatment monitoring. In this work, by using a specific‐designed fiber probe with a flat facet, we propose an "optical fan" strategy to screen K562 cells at the single‐cell level from a populations of RBCs. After the 980‐nm laser beam injected into the fiber probe, the RBCs were blown away but holding target K562 cells in place. Further, multiple leukemic cells can be screened from hundreds of red blood cells, providing an efficient approach for the cell screening. The experimental results were interpreted by the numerical simulation, and the stiffness of optical fan was also discussed. [ABSTRACT FROM AUTHOR]

Living Biosensors: Red-Blood-Cell Waveguide as a Living Biosensor and Micromotor (Adv. Funct. In article number 1905568, Yao Zhang, Baojun Li, and co-workers report a biocompatible biosensor and micromotor that are assembled with an in vivo red blood cell waveguide. The living biosensor is used for the diagnosis of pH-related disorders of the blood; the waveguide can rotate as a micromotor and transport microparticles to the target region. [Extracted from the article]

With great potential in intelligent sensing and actuating systems, biosensors and micromotors are expected to be powerful instruments for early diagnosis and drug delivery in precision medicine. However, it is difficult to ensure the synthetic biosensors and micromotors are compatible with biosystems because of their exogenous building blocks. Biocompatible biosensors and micromotors assembled are reported from living red blood cells (RBCs) optically bound into a waveguide using fiber probes. By monitoring light propagation of the RBC waveguide, the pH of blood solution is detected in real time with an accuracy of 0.05. This can be used for the diagnosis of pH‐related disorders of the blood. After diagnosis, optical torque is exerted on the RBC waveguide, allowing it to rotate as a micromotor and transport microparticles to a target region. The RBC waveguide is then constructed inside zebrafish blood vessels to validate in vivo application. The living biosensors and micromotors are expected to provide a "smart" platform for precise biosensing, medical analysis, and drug delivery. [ABSTRACT FROM AUTHOR]