Metasurface- and PCSEL-Based Structured Light for Monocular Depth Perception and Facial Recognition.

The novel depth-sensing system presented here revolutionizes structured light (SL) technology by employing metasurfaces and photonic crystal surface-emitting lasers (PCSELs) for efficient facial recognition in monocular depth-sensing. Unlike conventional dot projectors relying on diffractive optical elements (DOEs) and collimators, our system projects approximately 45,700 infrared dots from a compact 297-µm-dimention metasurface, drastically more spots (1.43 times) and smaller (233 times) than the DOE-based dot projector in an iPhone. With a measured field-of-view (FOV) of 158° and a 0.611° dot sampling angle, the system is lens-free and lightweight and boasts lower power consumption than vertical-cavity surface-emitting laser (VCSEL) arrays, resulting in a 5-10 times reduction in power. Utilizing a GaAs-based metasurface and a simplified optical architecture, this innovation not only addresses the drawbacks of traditional SL depth-sensing but also opens avenues for compact integration into wearable devices, offering remarkable advantages in size, power efficiency, and potential for widespread adoption.

Effects of coffee intake on airway hypersensitivity and immunomodulation: an in vivo murine study.

BACKGROUND/OBJECTIVES: Coffee is a complex chemical mixture, with caffeine being the most well-known bioactive substance. The immunomodulatory and anti-inflammatory properties of coffee and caffeine impact health in various aspects, including the respiratory system. The objective is to investigate the effects of coffee and caffeine on airway hyperresponsiveness and allergic reactions, as well as to analyze and compare associated cytokine profiles. MATERIALS/METHODS: BALB/c mice were intraperitoneally sensitized with ovalbumin (OVA) and given OVA inhalation to induce airway hypersensitivity. Two weeks after sensitization, they were intragastrically gavaged with coffee or caffeine, both containing 0.3125 mg caffeine, daily for 4 weeks. Control mice were fed with double-distilled water. Serum OVA-specific antibody levels were measured beforehand and 5 weeks after the first gavage. Airway hyperresponsiveness was detected by whole body plethysmography after gavage. Cytokine levels of bronchoalveolar lavage and cultured splenocytes were analyzed. RESULTS: Coffee effectively suppressed T helper 2-mediated specific antibody response. Airway responsiveness was reduced in mice treated with either coffee or caffeine. Compared to the control, coffee significantly reduced OVA-specific immunoglobulin (Ig) G, IgG1 and IgE antibody responses (P < 0.05). Caffeine also attenuated specific IgG and IgG1 levels, though IgE level was unaffected. Coffee significantly reduced interleukin (IL)-4 and increased IL-10 concentration in spleen cells and bronchoalveolar lavage fluid (P < 0.05). CONCLUSIONS: Coffee effectively attenuated airway hyperresponsiveness and systemic allergic responses induced by OVA food allergen in mice. As a complex composition of bioactive substances, coffee displayed enhanced immunomodulatory and anti-inflammatory effects than caffeine.

Compact structured light generation based on meta-hologram PCSEL integration.

Metasurfaces, a catalog of optical components, offer numerous novel functions on demand. They have been integrated with vertical cavity surface-emitting lasers (VCSELs) in previous studies. However, the performance has been limited by the features of the VCSELs such as low output power and large divergence angle. Although the solution of the module of VCSEL array could solve these issues, the practical application is limited by extra lens and large size. In this study, we experimentally demonstrate reconstruction of a holographic images using a compact integration of a photonic crystal surface-emitting laser and metasurface holograms designed for structured light generation. This research showcases the flexible design capabilities of metasurfaces, high output power (on the order of milliwatts), and the ability to produce well-uniformed images with a wide field of view without the need for a collection lens, making it suitable for 3D imaging and sensing.

Performance Analyses of Photonic-Crystal Surface-Emitting Laser: Toward High-Speed Optical Communication.

This study conducts comprehensive performance analyses of a commercial photonic-crystal surface-emitting laser (PCSEL) via small-signal measurement and the bit-error-rate test. Meanwhile, the radio frequency characteristics of the PCSEL are unveiled for the first time. Compared to the vertical-cavity surface-emitting lasers, the PCSEL shows great potential for a broader optical bandwidth that is benefited from the high optical-confinement factor. A maximum bandwidth of around 2.32 GHz is experimentally observed when the PCSEL was biased at 340 mA. Moreover, a theoretical calculation was applied to shed light on the characteristics of the small-signal measurement, providing a deep insight into the corresponding intrinsic response model. The signal transmission capability of the PCSEL was investigated as well. The maximum bit rate and corresponding rise time transmitted at 500 Mbps are 1.2 Gbps and 186.16 ps, respectively. Thus, a high-speed PCSEL can be realised with a shrunk form factor, serving as a promising candidate for the next-generation light sources in high-speed optical communication.

Ultracompact Nanophotonics: Light Emission and Manipulation with Metasurfaces.

Internet of Things (IoT) technology is prosperous for the betterment of human well-being. With the expeditious needs of miniature functional devices and systems for adaptive optics and light manipulation at will, relevant sensing techniques are thus in the urgent stage of development. Extensive developments in ultrathin artificial structures, namely metasurfaces, are paving the way for the next-generation devices. A bunch of tunable and reconfigurable metasurfaces with diversified catalogs of mechanisms have been developed recently, enabling dynamic light modulation on demand. On the other hand, monolithic integration of metasurfaces and light-emitting sources form ultracompact meta-devices as well as exhibiting desired functionalities. Photon-matter interaction provides revolution in more compact meta-devices, manipulating light directly at the source. This study presents an outlook on this merging paradigm for ultracompact nanophotonics with metasurfaces, also known as metaphotonics. Recent advances in the field hold great promise for the novel photonic devices with light emission and manipulation in simplicity.

Metformin Mitigates Nickel-Elicited Angiopoietin-Like Protein 4 Expression via HIF-1α for Lung Tumorigenesis.

Nickel (Ni), which is a carcinogenic workplace hazard, increases the risk of lung cancer. Angiopoietin-like protein 4 (ANGPTL4) is a multifunctional cytokine that is involved in both angiogenesis and metastasis, but its role in lung cancer is still not clear. In this study, we assessed the role of ANGPTL4 in lung carcinogenesis under nickel exposure and investigated the effects of the antidiabetic drug metformin on ANGPTL4 expression and lung cancer chemoprevention. Our results showed that ANGPTL4 is increased in NiCl2-treated lung cells in a dose- and time-course manner. The expression of ANGPTL4 and HIF-1α induced by NiCl2 were significantly repressed after metformin treatment. The downregulation of HIF-1α expression by ROS savenger and HIF-1α inhibitor or knockdown by lentiviral shRNA infection diminished NiCl2-activated ANGPTL4 expression. Chromatin immunoprecipitation and the luciferase assay revealed that NiCl2-induced HIF-1α hypoxia response element interactions activate ANGPTL4 expression, which is then inhibited by metformin. In conclusion, the increased presence of ANGPTL4 due to HIF-1α accumulation that is caused by nickel in lung cells may be one mechanism by which nickel exposure contributes to lung cancer progression. Additionally, metformin has the ability to prevent NiCl2-induced ANGPTL4 through inhibiting HIF-1α expression and its binding activity. These results provide evidence that metformin in oncology therapeutics could be a beneficial chemopreventive agent.

Metformin alleviates nickel-induced autophagy and apoptosis via inhibition of hexokinase-2, activating lipocalin-2, in human bronchial epithelial cells.

Autophagy is an intracellular recycling and degradation process for regulating tumor progression, survival and drug resistance. Nickel compounds have been identified as human carcinogens. However, the role of nickel-induced autophagy in lung carcinogenesis has not yet been fully elucidated. In this study, we determined that hexokinase 2 (HK2), which phosphorylates glucose and regulates autophagy, is the key mediator in nickel-induced autophagy in lung bronchial epithelial cells. We attempted to investigate the effects of the antidiabetic drug metformin on HK2 expression and lung cancer chemoprevention. Our results showed that metformin decreases nickel-induced autophagy and activation of apoptosis through inhibition of HK2 gene, protein and activity. Furthermore, we demonstrated that lipocalin 2 (LCN2), which is released by neutrophils at sites of infection and inflammation is involved in HK2-driven autophagy pathway. Knockdown of endogenous HK2 and LCN2 by shRNA reduced nickel-elicited autophagy and apoptosis, illustrating that metabolic alteration and inflammatory action are important in nickel-elicited carcinogenesis. We also determined the association between nickel-induced autophagy and apoptosis. Inhibition of nickel-induced autophagy abolished apoptotic cell death in chloroquine-treated, shLC3 Beas-2B cells and Atg5-/- MFFs. From TGCA database and immunohistochemistry analysis, HK2 and LCN2 expression increased in lung squamous cell carcinoma and their related adjacent normal tissues. Taken together, our results demonstrated that metformin alleviates NiCl2-induced autophagy and apoptosis via HK2-driven LCN2 activation in human bronchial epithelial cells. This novel mechanism provides a strategy for targeting nickel-elicited lung cancer progression, as well as for preventing HK2 cumulative damage triggered by environmental carcinogens.

Ellagic acid inhibits oxidized LDL-mediated LOX-1 expression, ROS generation, and inflammation in human endothelial cells.

BACKGROUND: LOX-1, a lectin-like receptor on endothelial cells, facilitates the uptake of oxidized low-density lipoprotein (oxLDL). Expression of LOX-1 is involved in the pathobiological effects of oxLDL in endothelial cells, including reactive oxygen species (ROS) generation, suppression of endothelial nitric oxide synthase (eNOS) activity, and leukocytic adhesion. Moderate consumption of phenolic-enriched food may have a protective effect against the development of atherosclerosis via the antioxidant capacity of phenolic compounds at the endothelial level. In this study, we determined whether ellagic acid, a polyphenolic compound widely distributed in fruits and nuts, protects against oxLDL-induced endothelial dysfunction by modulating the LOX-1-mediated signaling pathway. METHODS: Human umbilical vein endothelial cells (HUVECs) were pretreated with ellagic acid at doses of 5, 10, 15, and 20 µM for 2 hours and then incubated with oxLDL (150 µg/mL) for an additional 24 hours. RESULTS: LOX-1 protein expression was markedly lower after exposure to oxLDL in HUVECs pretreated with ellagic acid or diphenyleneiodonium, a well-known inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, than in HUVECs exposed to oxLDL alone, suggesting that ellagic acid deactivates NADPH oxidase. We also found that oxLDL activated the membrane assembly of p47phox, Rac1, gp91 and p22phox, and the subsequent induction of ROS generation; however, ROS generation was markedly suppressed in cells pretreated with ellagic acid or anti-LOX-1 monoclonal antibody. In addition, oxLDL down-regulated eNOS and up-regulated inducible NO synthase (iNOS), thereby augmenting the formation of NO and protein nitrosylation. Furthermore, oxLDL induced the phosphorylation of p38 mitogen-activated protein kinase, activated the NF-κB-mediated inflammatory signaling molecules interleukin-(IL) 6 and IL-8 and the adhesion molecules intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin, and stimulated the adherence of THP-1 (a human acute monocytic leukemia cell line) to HUVECs. Pretreatment with ellagic acid, however, exerted significant cytoprotective effects in all events. CONCLUSION: Findings from this study may provide insight into a possible molecular mechanism by which ellagic acid inhibits LOX-1-induced endothelial dysfunction. Our data indicate that ellagic acid exerts its protective effects by inhibiting NADPH oxidase-induced overproduction of superoxide, suppressing the release of NO by down-regulating iNOS, enhancing cellular antioxidant defenses, and attenuating oxLDL-induced LOX-1 up-regulation and eNOS down-regulation.

Ellagic acid protects endothelial cells from oxidized low-density lipoprotein-induced apoptosis by modulating the PI3K/Akt/eNOS pathway.

Endothelial apoptosis is a driving force in atherosclerosis development. Oxidized low-density lipoprotein (oxLDL) promotes inflammatory and thrombotic processes and is highly atherogenic, as it stimulates macrophage cholesterol accumulation and foam cell formation. Previous studies have shown that the phosphatidylinositol 3-kinase/Akt/endothelial nitric oxide synthase/nitric oxide (PI3K/Akt/eNOS/NO) pathway is involved in oxLDL-induced endothelial apoptosis. Ellagic acid, a natural polyphenol found in berries and nuts, has in recent years been the subject of intense research within the fields of cancer and inflammation. However, its protective effects against oxLDL-induced injury in vascular endothelial cells have not been clarified. In the present study, we investigated the anti-apoptotic effect of ellagic acid in human umbilical vein endothelial cells (HUVECs) exposed to oxLDL and explored the possible mechanisms. Our results showed that pretreatment with ellagic acid (5-20µM) significantly attenuated oxLDL-induced cytotoxicity, apoptotic features, and generation of reactive oxygen species (ROS). In addition, the anti-apoptotic effect of ellagic acid was partially inhibited by a PI3K inhibitor (wortmannin) and a specific eNOS inhibitor (cavtratin) but not by an ERK inhibitor (PD98059). In exploring the underlying mechanisms of ellagic acid action, we found that oxLDL decreased Akt and eNOS phosphorylation, which in turn activated NF-κB and downstream pro-apoptotic signaling events including calcium accumulation, destabilization of mitochondrial permeability, and disruption of the balance between pro- and anti-apoptotic Bcl-2 proteins. Those alterations induced by oxLDL, however, were attenuated by pretreatment with ellagic acid. The inhibition of oxLDL-induced endothelial apoptosis by ellagic acid is due at least in part to its anti-oxidant activity and its ability to modulate the PI3K/Akt/eNOS signaling pathway.