Breaking the symmetric spiral spectrum distribution of a Laguerre-Gaussian beam propagating in moderate-to-strong isotropic atmospheric turbulence.

We demonstrate that the spiral spectrum (also known as orbital angular momentum spectrum) of a Laguerre-Gaussian (LG) beam with topological charge (TC) l is asymmetrically broadened propagating through moderate-to-strong atmospheric turbulence, even the statistics of turbulence is isotropic. This phenomenon is quite different from that predicted in weak turbulence where the spiral spectrum of a disturbed LG beam is symmetric with respect to its TC number l. An explicit analytical expression of the spiral spectrum of the LG beam with l = 1 is derived based on the extend Huygens-Fresnel integral and quadratic approximation, which is used to illustrate the transition scenarios of the spiral spectrum from symmetry to asymmetry in weak-to-strong turbulence. The physical mechanism for the asymmetric spiral spectrum in moderate-to-strong turbulence is thoroughly discussed. Our results are confirmed by the multi-phase screen numerical simulations and are consistent with the experimental results reported in Phys. Rev. A105, 053513 (2022)10.1103/PhysRevA.105.053513 and Opt. Lett.38, 4062 (2013)10.1364/OL.38.004062.

Generation of non-uniformly correlated sources with controllable beam profile by devising its statistics in the spatial frequency domain.

We introduce an efficient approach to simultaneously tailor the spatial profile and the degree of coherence (DOC) of partially coherent light by devising its statistical properties in the spatial frequency domain. The relationship between the beam profile and the DOC in the source plane and the correlation function and power spectrum in the spatial frequency domain is analyzed in detail. This approach enables us to generate partially coherent sources with spatially uniform or non-uniform coherence states, and the source profiles are controlled. The condition for switching two coherence states is given through two theoretical examples. Furthermore, we validate our approach in experiment through generating two kinds of spatially non-uniform correlated sources with controllable beam profiles. The experimental results agree well with our theoretical analysis.

Self-healing properties of optical pin beams.

In some situations, the beam is partially blocked by an obstacle during propagation, and the influence of the obstacle and ways to decrease the influence have been studied for practical applications. The self-healing effect of Bessel beams is considered as one potential technology for this. The optical pin beam (OPB) can evolve into a Bessel-like beam and can retain its robust property after long-distance propagation. In this paper, we study the propagation property of an OPB after it is partially blocked by an obstacle. We observe the self-healing effects of the OPB and find that it exhibits robust self-healing abilities. An experiment is conducted to confirm the self-healing effect of the OPB. As one example of the application of the self-healing effect, the radiation forces of an obstructed OPB are calculated. Our findings may have important applications in various fields such as micro-imaging, trapping, and long-distance optical communication under disturbance conditions.

Extracellular vesicles from Lactobacillus druckerii inhibit hypertrophic scar fibrosis.

BACKGROUND: Hypertrophic scars (HS) affect millions of people each year and require better treatment strategies. Bacterial extracellular vesicles (EVs) are advantaged by low cost and high yield which was commonly used in the treatment of diseases. Here, we investigated the therapeutic efficacy of EVs obtained from Lactobacillus druckerii in hypertrophic scar. In vitro, the effects of Lactobacillus druckerii-derived EVs (LDEVs) on Collagen I/III and α-SMA in fibroblasts obtained from HS. In vivo, a scleroderma mouse model was used to investigate the effects of LDEVs on fibrosis. The impact of LDEVs on excisional wound healing was explored. The different proteins between PBS and LDEVs treated fibroblasts derived from hypertrophic scar were studied by untargeted proteomic analysis. RESULTS: In vitro, LDEVs treatment significantly inhibited the expression of Collagen I/III and α-SMA and cell proliferation of fibroblasts derived from HS. In vivo, LDEVs withdrawn the hypertrophic scar formation in scleroderma mouse model and decreased the expression of α-SMA. LDEVs promoted the proliferation of skin cells, new blood vessel formation and wound healing in excisional wound healing mice model. Moreover, proteomics has shown that LDEVs inhibit hypertrophic scar fibrosis through multiple pathways. CONCLUSIONS: Our results indicated that Lactobacillus druckerii-derived EVs has the potential application in the treatment of hypertrophic scars and any other fibrosis diseases.

Taurine Protects against the Fatty Liver Hemorrhagic Syndrome in Laying Hens through the Regulation of Mitochondrial Homeostasis.

Metabolic-associated fatty liver disease (MAFLD) is a chronic liver disease caused by fat deposition in the liver of humans and mammals, while fatty liver hemorrhagic syndrome (FLHS) is a fatty liver disease in laying hens which can increase the mortality and cause severe economic losses to the laying industry. Increasing evidence has shown a close relationship between the occurrence of fatty liver disease and the disruption of mitochondrial homeostasis. Studies have proven that taurine can regulate hepatic fat metabolism, reduce hepatic fatty deposition, inhibit oxidative stress, and alleviate mitochondrial dysfunction. However, the mechanisms by which taurine regulates mitochondrial homeostasis in hepatocytes need to be further studied. In this study, we determined the effects and mechanisms of taurine on high-energy low-protein diet-induced FLHS in laying hens and in cultured hepatocytes in free fatty acid (FFA)-induced steatosis. The liver function, lipid metabolism, antioxidant capacity, mitochondrial function, mitochondrial dynamics, autophagy, and biosynthesis were detected. The results showed impaired liver structure and function, mitochondrial damage and dysfunction, lipid accumulation, and imbalance between mitochondrial fusion and fission, mitochondrial autophagy, and biosynthesis in both FLHS hens and steatosis hepatocytes. Taurine administration can significantly inhibit the occurrence of FLHS, protect mitochondria in hepatocytes from disease induced by lipid accumulation and FFA, up-regulate the expression levels of Mfn1, Mfn2, Opa1, LC3I, LC3II, PINK1, PGC-1α, Nrf1, Nrf2, and Tfam, and down-regulate the expression levels of Fis1, Drp1, and p62. In conclusion, taurine can protect laying hens from FLHS through the regulation of mitochondrial homeostasis, including the regulation of mitochondrial dynamics, autophagy, and biosynthesis.

Rotation of degree of coherence and redistribution of transverse energy flux induced by non-circular degree of coherence of twisted partially coherent sources.

It is known that a twisted Gaussian Schell-model (TGSM) beam with elliptical Gaussian amplitude will rotate its beam spot upon propagation because of the vortex structure of the transverse energy flux. In this paper, we study a special kind of twisted partially coherent beams named twisted Hermite-Gaussian correlated Schell model (HGCSM) beam whose degree of coherence (DOC) is non-circularly symmetric but the source amplitude is of the circular Gaussian profile. Our results reveal that the beam spot (average intensity distribution) does not rotate during propagation even if the circular symmetry of the beam spot is broken. However, the DOC pattern shows the rotation under propagation. From the investigation of the transverse energy flux and OAM density flux, we attribute the nontrivial rotation phenomenon to the redistribution of the transverse energy flux by non-circular DOC. Furthermore, based on Hyde's approach [J. Opt. Soc. Am. A37, 257 (2020)10.1364/JOSAA.381772], we introduce a method for the generation of this class of twisted partially coherent sources. The non-rotation of the beam spot and rotation of the DOC are demonstrated in experiment.

Orbital angular momentum spectrum of pin-like optical vortex beams in turbulent atmosphere.

The analytical formula of the probability density of a single orbital angular momentum (OAM) mode for pin-like optical vortex beams (POVBs) in turbulent atmosphere is derived. Its OAM spectrum in the receiving plane is obtained by the numerical calculation. For comparison, the OAM spectrum of commonly Gaussian vortex beams is showed, too. Those results show that POVBs show good performance on resisting the cross talk of the OAM mode induced by the turbulence in some cases, such as smaller radius of the receiving aperture, longer propagation distance, and stronger turbulence. Our finding has application in free-space optical communication based on the OAM mode.

Taurine Prevents AFB1-Induced Renal Injury by Inhibiting Oxidative Stress and Apoptosis.

Aflatoxin B1 (AFB1) is one of the most toxic mycotoxins, which can cause serious kidney damage after ingestion. Taurine protects the kidney, an effect related to its antioxidation and anti-apoptotic actions. In the present study, taurine was administered to detect the protective effect and mechanism of taurine on AFB1-induced renal injury in rats. The results show that taurine ameliorated the increase in serum blood urea nitrogen (BUN), blood creatinine (CRE), blood uric acid (UA), cystatin c (Cys-c), and urinary protein and AKP levels. Taurine also inhibits the content of superoxide dismutase (SOD), total antioxidant capacity (T-AOC), catalase (CAT), glutathione (GSH), glutathione peroxidase (GSH-Px), succinate dehydrogenase (SDH), and the mRNA expression of SOD, nicotinamide adenine dinucleotide phosphate-quinine oxidoreductase 1 (NQO1), γ-glutamylcysteine synthetase (γ-GCS), heme oxygenase-1 (HO-1), and glutamate cysteine ligase catalytic (GCLC) in rat kidney tissue. The apoptotic rate of renal cells was decreased by taurine through inhibition of a mitochondrial mechanism. In summary, we found that taurine prevents AFB1-induced renal injury via enhanced antioxidant ability and mitochondrial-dependent apoptosis.

Taurine Prevents Liver Injury by Reducing Oxidative Stress and Cytochrome C-Mediated Apoptosis in Broilers Under Low Temperature.

Hypoxia caused by low ambient temperature leads to hypoxemia in broilers, which aggravates the metabolic burden of the liver. Liver damage is closely related to oxidative stress and apoptosis. It has been proved that taurine can reduce oxygen free radicals, exert antioxidant properties, and inhibit mitochondria-dependent apoptosis. This experiment aimed to determine whether taurine could prevent liver damage by inhibiting oxidative stress and the cytochrome c-mediated apoptotic pathway in broilers under low ambient temperature. Broilers were given 1% taurine in drinking water, and the temperature was raised at 10 °C ~ 12 °C from 21 to 42 days. At 28 and 42 days, the hepatic tissues were collected. The antioxidant capacity of liver tissues and mRNA expression levels of the factors related with cytochrome c-medicated apoptosis pathway were measured. The results showed taurine significantly increased the total antioxidant capacity (T-AOC) at 28 days. Furthermore, taurine also increased the activities of glutathione peroxidase (GSH-PX) while reducing malondialdehyde (MDA) concentration at 28 days and 42 days. Our results also revealed that taurine significantly increased the mRNA expression levels of Hsp 27 and Hsp 90 while decreasing caspase-3 mRNA expression in broiler hepatocytes at 28 days. In addition, taurine also upregulated the expression level of Bcl-2 at 42 days. In summary, the present study found that taurine enhances the antioxidant ability and alleviates cytochrome c-mediated apoptosis in hepatic tissue of broilers under low temperature.

The Regulatory Effects of Taurine on Neurogenesis and Apoptosis of Neural Stem Cells in the Hippocampus of Rats.

The promotion of neurogenesis from neural stem cells (NSCs) in the hippocampus was found to be the most fundamental and effective therapy for depression. Our previous studies proved an antidepressive effect of taurine on rats, but the exact mechanism remains unclear. In this study, CUMS model was established in rats, and NSCs were cultured in vitro to investigate the protective effect and mechanisms of taurine on neurogenesis and apoptosis in CUMS rats and glutamate-injured NSCs. The results showed that ki67-positive cells were significantly increased by taurine, while apoptosis in the DG of CUMS rats was significantly inhibited by taurine. In vitro study, cell viability, Brdu+, ß-tubulin III+, and GFAP+ cells in taurine-treated cells were significantly higher, while apoptosis rate was lower than the glutamate-treated cells. The protein expression of BDNF and its downstream pathway was upregulated by taurine administration. The results demonstrated that taurine can increase the survival, proliferation, and differentiation of NSCs; this protective effect of taurine may be due to the upregulation of BDNF/ERK/CREB signaling pathway. On the other hand, taurine can also inhibit abnormal apoptosis induced by CUMS or glutamate, the mechanism of which may be due to its antioxidative ability.

Intervention Effect of Taurine on LPS-Induced Intestinal Mechanical Barrier Injury in Piglets.

Taurine has the advantages of being safe, highly efficient, chemically stabile, and biologically active, together with having versatile functions. Presently, it is employed as a veterinary feed additive in animal research. The tight junctions that constitute the intestinal epithelial cells are the most critical structures for ensuring regular and uninterrupted digestion and absorption of food by the intestinal mucosa, while at the same time resisting invasions by toxins. The purpose of this study was to investigate the protective effect and mechanism of taurine action on intestinal mechanical barrier function of piglets that were infected with LPS. The results showed that 0.3% taurine inhibits LPS-driven increase in intestinal permeability and intestinal mucosal injury, the rise in the ratio of villus length to crypt depth within the duodenum, jejunum, and ileum, and the significant enhancement in the expression of tight junction protein-related genes. In summary, dietary taurine significantly reduces intestinal mucosal structural damage and intestinal mucosal permeability while increasing gene expression of tight junction proteins of the intestinal mucosa of piglets induced by LPS, thereby enhancing the effect of intestinal mucosal mechanical barriers.

Taurine Prevents LPS-Induced Liver Injury in Weaned Piglets.

This study employed taurine as a feed additive to explore the prophylactic effect of taurine on LPS-induced hepatic injury in piglets. The pathological shifts within hepatic tissue were observed by HE staining. Serum levels of ALT and AST together with SOD, CAT, GSH-PX activity, and MDA serum and liver levels were detected. TUNEL was used to detect apoptosis, while qPCR was employed to detect HO-1, Nrf-2, Bcl2, BAX, Caspase-3, and NF- κB p65 transcriptomic expression levels. TRL4, Caspase-3, Nrf-2, and NF- κB p-p65/NF- κB p65 were detected by Western blot. The results revealed that taurine reduces LPS-induced pathological damage of hepatic tissue and reduces the levels of ALT and AST in pig serum. The transcriptomic expression levels of HO-1 and Nrf-2 were upregulated, and proteomic expression of Nrf-2 was increased. SOD, CAT, and GSH-PX activity was elevated, while MDA content was reduced in serum and liver. The levels of mRNA of BAX and Caspase-3 were downregulated, but mRNA content of Bcl2 was increased, and the protein levels of TRL4, NF-κB p-p65/NF-κB p65, and Caspase-3 were diminished. Overall, the degree of hepatocyte apoptosis was also significantly reduced. In conclusion, taurine reduces LPS-induced injury of piglet liver, while reducing hepatocyte apoptotic levels. These data provide a scientific basis for the selection of animal feed additives and lay a foundation for the healthy and sustainable development of the porcine industry.

Absolute testing method of shift-rotation based on the influence function.

The absolute testing of an optical surface with the shift-rotation method is an effective way to obtain an optical surface with high accuracy. The traditional shift-rotation method based on Zernike polynomials has a large number of computations and poor fitting accuracy for high frequency. Additionally, the number of calculations of the pixel-level spatial frequency method in solving the test and reference error based on each pixel is too large, which leads to poor practicability in reality. An optimized absolute testing method of shift-rotation based on the influence function is presented in this paper. By introducing the concept of the influence function in adaptive optics instead of a Zernike polynomial, the calculation accuracy of the mid-and high-frequency surface is improved, and higher precision of the absolute surface can be obtained. Relevant theoretical simulation and experimental verification are carried out. The experimental results compared with the Zernike and pixel-level methods show that the reference and test surface can be well reconstructed by using the proposed shift-rotation method based on the influence function.

Heterodimers of metal nanoparticles: synthesis, properties, and biological applications.

Heterodimers of metal nanoparticles consist of two metals, come in many sizes and adopt various shapes. They offer unique properties due to the presence of two metals and have the extraordinary flexibility needed to serve as a multipurpose platform for diverse applications in areas including photonics, sensing, and catalysis. Heterodimer nanoparticles contain different metals that contribute to extraordinary surface plasmon resonance (SPR), surface-enhanced Raman scattering (SERS), and catalytic properties. These properties make them versatile molecules that can be used in intracellular imaging, as antibacterial agents, as photocatalytic and biological macromolecules and for the detection of chemical substances. Moreover, heterodimer nanoparticles are composed of the two metals within larger molecules that provide more choices for modification and application. In this review, we briefly summarize the lesser-known aspects of heterodimers, including some of their properties, and present concrete examples of recent progress in synthesis and applications. This review provides a perspective on achievements and suggests a framework for future research with a focus on the synthesis and application of heterodimers. We also explore the possible applications of heterodimer nanoparticles based on their unique properties.

ING4 alleviated lipopolysaccharide-induced inflammation by regulating the NF-κB pathway via a direct interaction with SIRT1.

Sepsis is a complex inflammatory disorder in which high mortality is associated with an excessive inflammatory response. Inhibitor of growth 4 (ING4), which is a cofactor of histone acetyltransferase and histone deacetylase complexes, could negatively regulate this inflammation. However, the exact molecular signaling pathway regulated by ING4 remains uncertain. As a pivotal histone deacetylase, Sirtuin1 (SIRT1), which is widely accepted to be an anti-inflammatory molecule, has not been found to be linked to ING4. This study investigated how ING4 is involved in the regulation of inflammation by constructing lipopolysaccharide (LPS)-induced macrophage and mouse sepsis models. Our results revealed that ING4 expression decreased, whereas the levels of proinflammatory cytokines increased in LPS-stimulated cultured primary macrophages and RAW 264.7 cells. ING4 transfection was confirmed to alleviate the LPS-induced upregulation of proinflammatory cytokine expression both in vitro and in vivo. In addition, ING4-overexpressing mice were hyposensitive to an LPS challenge and displayed reduced organ injury. Furthermore, immunoprecipitation indicated a direct interaction between ING4 and the SIRT1 protein. Moreover, ING4 could block nuclear factor-kappa B (NF-κB) P65 nuclear translocation and restrict P65 acetylation at lysine 310 induced by LPS treatment. These results are the first to clarify that the anti-inflammatory role of ING4 is associated with SIRT1, through which ING4 inhibits NF-κB signaling activation. Our studies provide a novel signaling axis involving ING4/SIRT1/NF-κB in LPS-induced sepsis.

Taurine prevents cardiomyocyte apoptosis by inhibiting the calpain-1/cytochrome c pathway during RVH in broilers.

The calpain-1-activated apoptotic pathway plays a key role in right ventricular hypertrophy (RVH). Taurine has been shown to attenuate apoptosis by inhibiting calpain activity. This experiment aimed to determine whether taurine could prevent RVH by inhibiting the calpain-1/cytochrome c apoptotic pathway. The broilers were given 1% taurine dissolved in drinking water and were raised at 10 °C ~ 12 °C from day 21 to day 42. At 21 d, 28 d, 35 d and 42 d, the right ventricular (RV) tissues were collected. Increased RVH index, angiotensin II, norepinephrine and atrial natriuretic peptide mRNA expression were reduced by taurine in the broiler RVs. Taurine obviously inhibited cardiomyocyte apoptosis via maintaining the mitochondrial membrane potential and decreased the activation of caspase-9 and caspase-3 in the broiler RVs. The antioxidant assay demonstrated that taurine enhanced the activities of superoxide dismutase, total antioxidant capacity and glutathione peroxidase and the glutathione/glutathione disulfide ratio. Western blot results revealed that taurine also downregulated the expression of calpain-1 and cytosolic cytochrome c while upregulating the expression of Bcl-2/Bax and mitochondrial cytochrome c in broiler cardiomyocytes during RVH. In summary, we found that taurine could enhance cardiomyocyte antioxidant ability and further prevented cardiomyocyte apoptosis by inhibiting the calpain-1/cytochrome c pathway during RVH in broilers.

Taurine attenuates isoproterenol-induced H9c2 cardiomyocytes hypertrophy by improving antioxidative ability and inhibiting calpain-1-mediated apoptosis.

Pathological cardiac hypertrophy is ultimately accompanied by cardiomyocyte apoptosis. Apoptosis mainly related to calpain-1-mediated apoptotic pathways. Studies had proved that taurine can maintain heart health through antioxidation and antiapoptotic functions, but the effect of taurine on cardiac hypertrophy is still unclear. This study aimed to determine whether taurine could inhibit calpain-1-mediated mitochondria-dependent apoptotic pathways in isoproterenol (ISO)-induced hypertrophic cardiomyocytes. We found that taurine could inhibit the increase in cell surface area and reduce the protein expression levels of the hypertrophic markers atrial natriuretic peptide, brain natriuretic polypeptide, and ß-myosin heavy chain. Taurine also reduced ROS, intracellular Ca2+ overload and mitochondrial membrane potential. Moreover, taurine inhibited cardiomyocyte apoptosis by decreasing the protein expression of calpain-1, Bax, t-Bid, cytosolic cytochrome c, Apaf-1, cleaved caspase-9 and cleaved caspase-3 and by enhancing calpastatin and Bcl-2 protein expression. Calpain-1 small interfering RNA transfection results showed similar antiapoptotic effects as the taurine prevention group. However, compared with the two treatments, taurine inhibited the expression of cleaved caspase-9 more significantly. Therefore, we believe that taurine prevents ISO-induced H9c2 cardiomyocyte hypertrophy by inhibiting oxidative stress, intracellular Ca2+ overload, the calpain-1-mediated mitochondria-dependent apoptotic pathway and cleaved caspase-9 levels.

Evolution properties of the orbital angular momentum spectrum of twisted Gaussian Schell-model beams in turbulent atmosphere.

We derive the analytical formula of the energy weight of each orbital angular momentum (OAM) mode of twisted Gaussian Schell-model (TGSM) beams propagating in weak turbulent atmosphere. The evolution of its OAM spectrum is studied by numerical calculation. Our results show that the OAM spectrum of a TGSM beam changes with the beam propagating in turbulent atmosphere, which is completely different from that of the TGSM beam propagating in free space. Furthermore, influences of the source parameters and the turbulence parameters on the OAM spectrum of a TGSM beam in turbulent atmosphere are analyzed. It is found that the source parameters and turbulence parameters, such as twist factor, coherence length, beam waist size, and structure constant, have a significant influence on the OAM spectrum, but the value of the wavelength and inner scale have little influence. Increasing the beam waist size or decreasing the coherence length would lead to the OAM spectrum broadened in the source plane, but would be robust for the OAM modes of the TGSM beam in the turbulent atmosphere. It is clear that the bigger the value of the twist factor, the more asymmetric the OAM mode of the TGSM beam is, and the better mode distribution can be maintained when it propagates in turbulent atmosphere. Our results have potential applications in reducing the error rate of free-space optical communication and detecting the atmospheric parameters.

Mobility Control of Unmanned Aerial Vehicle as Communication Relay to Optimize Ground-to-Air Uplinks.

In recent years, unmanned aerial vehicles (UAVs) have been considered an ideal relay platform for enhancing the communication between ground agents, because they fly at high altitudes and are easy to deploy with strong adaptabilities. Their maneuvering allows them to adjust their location to optimize the performance of links, which brings out the relay UAV autonomous mobility control problem. This work addressed the problem in a novel scene with mobile agents and completely unknown wireless channel properties, using only online measured information of received signal strength (RSS) and agent positions. The problem is challenging because of the unknown and dynamic radio frequency (RF) environment cause by agents and UAV maneuvering. We present a framework for both end-to-end communication and multi-agent-inter communication applications, and focus on proposing: (1) least square estimation-based channel approximation with consideration of environment effects and, (2) gradient-based optimal relay position seeking. Simulation results show that considering the environmental effects on channel parameters is meaningful and beneficial in using UAV as relays for the communication of multiple ground agents, and validate that the proposed algorithms optimizes the network performance by controlling the heading of the UAV.

The Akt/FoxO/p27Kip1 axis contributes to the anti-proliferation of pentoxifylline in hypertrophic scars.

Hypertrophic scars (HS) are characterized by the excessive production and deposition of extracellular matrix (ECM) proteins. Pentoxifylline (PTX), a xanthine derived antioxidant, inhibits the proliferation, inflammation and ECM accumulation of HS. In this study, we aimed to explore the effect of PTX on HS and further clarify the mechanism of PTX-induced anti-proliferation. We found that PTX could significantly attenuate proliferation of HS fibroblasts and fibrosis in an animal HS model. PTX inhibited the proliferation of HSFs in a dose- and time-dependent manner, and this growth inhibition was mainly mediated by cell cycle arrest. Transcriptome sequencing showed that PTX affects HS formation through the PI3K/Akt/FoxO1 signalling pathway to activate p27Kip1 . PTX down-regulated p-Akt and up-regulated p-FoxO1 in TGF-ß1 stimulated fibroblasts at the protein level, and simultaneously, the expression of p27Kip1 was activated. In a mouse model of HS, PTX treatment resulted in the ordering of collagen fibres. The results revealed that PTX regulates TGFß1-induced fibroblast activation and inhibits excessive scar formation. Therefore, PTX is a promising agent for the treatment of HS formation.