Observation of high-order imaginary Poynting momentum optomechanics in structured light.

The imaginary Poynting momentum (IPM) of light has been captivated as an unusual origin of optical forces. However, the IPM force is predicted only for dipolar magnetoelectric particles that are hardly used in optical manipulation experiments. Here, we report a whole family of high-order IPM forces for not only magnetoelectric but also generic Mie particles, assisted with their excited higher multipoles within. Such optomechanical manifestations derive from a nonlocal contribution of the IPM to the optical force, which can be remarkable even when the incident IPM is small. We observe the high-order optomechanics in a structured light beam, which, despite carrying no angular momentum, is able to set normal microparticles into continuous rotation. Our results provide unambiguous evidence of the ponderomotive nature of the IPM, expand the classification of optical forces, and open new possibilities for levitated optomechanics and micromanipulations.

Enantioselective Optical Trapping of Multiple Pairs of Enantiomers by Focused Hybrid Polarized Beams.

Enantiomers (opposite chiral molecules) usually exhibit different effects when interacting with chiral agents, thus the identification and separation of enantiomers are of importance in pharmaceuticals and agrochemicals. Here an optical approach is proposed to enantioselective trapping of multiple pairs of enantiomers by a focused hybrid polarized beam. Numerical results indicate that such a focused beam shows multiple local optical chirality of opposite signs in the focal plane, and can trap the corresponding enantiomers near the extreme value of optical chirality density according to the handedness of enantiomers. The number and positions of trapped enantiomers can be changed by altering the value and sign of polarization orders of hybrid polarized beams, respectively. The key to realizing enantioselective optical trapping of enantiomers is that the chiral optical force exerted on enantiomers in this focused field is stronger than the achiral optical force. The results provide insight into the optical identification and separation of multiple pairs of enantiomers and will find applications in chiral detection and sensing.

Biological features of human influenza A(H3N8) viruses in China.

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.

Reversible lateral optical force on phase-gradient metasurfaces for full control of metavehicles.

Photonics is currently undergoing an era of miniaturization thanks in part to two-dimensional (2D) optical metasurfaces. Their ability to sculpt and redirect optical momentum can give rise to an optical force, which acts orthogonally to the direction of light propagation. Powered by a single unfocused light beam, these lateral optical forces (LOFs) can be used to drive advanced metavehicles and are controlled via the incident beam's polarization. However, the full control of a metavehicle on a 2D plane (i.e. forward, backward, left, and right) with a sign-switchable LOF remains a challenge. Here we present a phase-gradient metasurface route for achieving such full control while also increasing efficiency. The proposed metasurface is able to deflect a normally incident plane wave in a traverse direction by modulating the plane wave's polarization, and results in a sign-switchable recoil LOF. When applied to a metavehicle, this LOF enables a level of motion control that was previously unobtainable.

Inverse Optical Torques on Dielectric Nanoparticles in Elliptically Polarized Light Waves.

Elliptically polarized light waves carry the spin angular momentum (SAM), so they can exert optical torques on nanoparticles. Usually, the rotation follows the same direction as the SAM due to momentum conservation. It is counterintuitive to observe the reversal of optical torque acting on an ordinary dielectric nanoparticle illuminated by an elliptically or circularly polarized light wave. Here, we demonstrate that negative optical torques, which are opposite to the direction of SAM, can ubiquitously emerge when elliptically polarized light waves are impinged on dielectric nanoparticles obliquely. Intriguingly, the rotation can be switched between clockwise and counterclockwise directions by controlling the incident angle of light. Our study suggests a new playground to harness polarization-dependent optical force and torque for advancing optical manipulations.

Screening and Research on Skin Barrier Damage Protective Efficacy of Different Mannosylerythritol Lipids.

Mannosylerythritol lipids (MELs) may prevent skin barrier damage, although their protective mechanisms and active monomeric constituents remain unclear. Here, three MELs were extracted from Candida antarctica cultures containing fermented olive oil then purified using silica gel-based column chromatography and semipreparative HPLC. All three compounds (MEL-A, MEL-B, MEL-C) were well separated and stable, and reliable materials were used for NMR and HRESIMS chemical structure determinations and for assessing MELs' protective effects against skin damage. Notably, MEL-B and MEL-C effectively protected HaCaT cells from UVB-induced damage by upregulating the contents of filaggrin (FLG) and transglutaminase-1 (TGM1), as determined via ELISA. Moreover, MEL-B treatment (20 µg/mL) of UVB-irradiated HaCaT cells led to the upregulation of both the expression of mRNA genes and the key proteins FLG, LOR, and TGM1, which are known to be decreased in damaged skin cells. Additionally, histopathological analysis results revealed a markedly reduced intracellular vacuolation and cell damage, reflecting improved skin function after MEL-B treatment. Furthermore, immunofluorescence results revealed that MEL-B protected EpiKutis® three-dimensional cultured human skin cells from sodium dodecyl sulfate-induced damage by up-regulating FLG, LOR, and TGM1 expression. Accordingly, MELs' protection against skin barrier damage depended on MEL-B monomeric constituent activities, thus highlighting their promise as beneficial ingredients for use in skin-care products.

Akt activation-dependent protective effect of wild ginseng adventitious root protein against UVA-induced NIH-3T3 cell damage.

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.

Bidirectional Transport of Nanoparticles and Cells with a Bio-Conveyor Belt.

The bidirectional transport of nanoparticles and biological cells is of great significance in efficient biological assays and precision cell screening, and can be achieved with optical conveyor belts in a noncontact and noninvasive manner. However, implantation of these belts into biological systems can present significant challenges owing to the incompatibility of the artificial materials. In this work, an optical conveyor belt assembled from natural biological cells is proposed. The diameter of the belt (500 nm) is smaller than the laser wavelength (980 nm) and, therefore, the evanescent wave stably traps the nanoparticles and cells on the belt surface. By adjusting the relative power of the lasers injected into the belt, the particles or cells can be bidirectionally transported along the bio-conveyor belt. The experimental results are numerically interpreted and the transport velocities are investigated based on simulations. Further experiments show that the bio-conveyor belt can also be assembled with mammalian cells and then applied to dynamic cell transport in vivo. The bio-conveyor belt might provide a noninvasive and biocompatible tool for biomedical assays, drug delivery, and biological nanoarchitectonics.

Azimuthal Imaginary Poynting Momentum Density.

The momentum of light beams can possess azimuthal densities, circulating around the beam axis and inducing intriguing mechanical effects in local light-matter interaction. Belinfante's spin momentum loops in circularly polarized beams, while the canonical momentum spirals in helically phased beams. However, a similar behavior of their imaginary counterpart, the so-called imaginary Poynting momentum (IPM), has not yet emerged. The foremost purpose of the present work is to put forward the discovery of this IPM vortex. We show that a simple superposition of radially and azimuthally polarized beams can form an IPM of completely azimuthal density. Additionally, the azimuthal IPM density can exist with a donut beam-intensity distribution and even with a vanishing azimuthal component of all other momenta. This uncovers the existence of a new mechanical effect which broadens the area of optical micromanipulation by achieving optical rotation of isotropic spheres, in the absence of both spin and orbital angular momenta. Our findings enrich the local dynamic properties of electromagnetic fields, highlighting the rotational action of their IPM, and thus its mechanical effect on microparticles and nanoparticles.

Vanillic acid in Panax ginseng root extract inhibits melanogenesis in B16F10 cells via inhibition of the NO/PKG signaling pathway.

Panax ginseng C. A. Meyer has been widely used in skin care. Our previous study showed that the phenolic acids in ginseng root extract (GRE) impart inhibitory effects on melanogenesis. In this study, we found that as the most abundant component of phenolic acids in GRE, vanillic acid decreased tyrosinase activity and melanin levels with or without α-MSH stimulation and suppressed the expression of microphthalmia-associated transcription factor (MITF) and melanogenic enzymes in B16F10 cells. Furthermore, vanillic acid downregulated NOS activity, nitric oxide (NO) content, cGMP level, guanylate cyclase (GC) and protein kinase G (PKG) activity, and the phosphorylation of cAMP-response element-binding protein (CREB), whereas arbutin had no effect on the NO/PKG pathway. These findings indicate that vanillic acid in GRE suppressed melanogenesis by inhibiting the NO/PKG signaling pathways. This study provides a potential mechanism underlying the inhibitory effect of ginseng on melanogenesis.

Adaptive Sparse Memory Networks for Efficient and Robust Video Object Segmentation.

Recently, memory-based networks have achieved promising performance for video object segmentation (VOS). However, existing methods still suffer from unsatisfactory segmentation accuracy and inferior efficiency. The reasons are mainly twofold: 1) during memory construction, the inflexible memory storage mechanism results in a weak discriminative ability for similar appearances in complex scenarios, leading to video-level temporal redundancy, and 2) during memory reading, matching robustness and memory retrieval accuracy decrease as the number of video frames increases. To address these challenges, we propose an adaptive sparse memory network (ASM) that efficiently and effectively performs VOS by sparsely leveraging previous guidance while attending to key information. Specifically, we design an adaptive sparse memory constructor (ASMC) to adaptively memorize informative past frames according to dynamic temporal changes in video frames. Furthermore, we introduce an attentive local memory reader (ALMR) to quickly retrieve relevant information using a subset of memory, thereby reducing frame-level redundant computation and noise in a simpler and more convenient manner. To prevent key features from being discarded by the subset of memory, we further propose a novel attentive local feature aggregation (ALFA) module, which preserves useful cues by selectively aggregating discriminative spatial dependence from adjacent frames, thereby effectively increasing the receptive field of each memory frame. Extensive experiments demonstrate that our model achieves state-of-the-art performance with real-time speed on six popular VOS benchmarks. Furthermore, our ASM can be applied to existing memory-based methods as generic plugins to achieve significant performance improvements. More importantly, our method exhibits robustness in handling sparse videos with low frame rates.

Ginsenoside Rf in wild ginseng adventitious roots extract inhibits melanogenesis via cAMP/PKA and NO/cGMP signalling pathways in α-melanocyte-stimulating hormone-stimulated B16F10 mouse melanoma cells and zebrafish.

The scarcity of more effective wild ginseng has severely limited its use, culturing of adventitious roots from wild ginseng were its good substitute. In this study, we found ginsenoside Rf as the special component in adventitious roots extract significantly decreased melanin levels and tyrosinase activity in B16F10 cells and zebrafish, and suppressed the expression of microphthalmia-associated transcription factor and melanogenic enzymes in B16F10 cells. Notably, Rf treatment of B16F10 cells led to reduced cell levels of adenosine cyclic 3', 5'-monophosphate (cAMP), nitric oxide (NO), and guanoside cyclic 3', 5'-monophosphate (cGMP), and reduced activities of adenylate cyclase (AC), protein kinase A (PKA), guanylate cyclase (GC), and protein kinase G (PKG), which suggest Rf anti-melanogenic activity potentially involved inhibition of AC/cAMP/PKA and NO/GC/cGMP/PKG signalling pathway. This work provides experimental basis for skin-lightening effect of wild ginseng adventitious roots and their functional part.

Rapid adaptive substitution of L226Q in HA protein increases the pathogenicity of H9N2 viruses in mice.

Background: Since the first human infection with H9N2 virus was reported in 1998, the number of cases of H9N2 infection has exceeded one hundred by 2021. However, there is no systematic description of the biological characteristics of H9N2 viruses isolated from humans. Methods: Therefore, this study analyzed the pathogenicity in mice of all available H9N2 viruses isolated from human cases in China from 2013 to 2021. Results: Although most of the H9N2 viruses analyzed showed low or no pathogenicity in mice, the leucine to glutamine substitution at residue 226 (L226Q) in the hemagglutinin (HA) protein rapidly emerged during the adaptation of H9N2 viruses, and was responsible for severe infections and even fatalities. HA amino acid 226Q conferred a remarkable competitive advantage on H9N2 viruses in mice relative to viruses containing 226L, increasing their virulence, infectivity, and replication. Conclusion: Thus, our study demonstrates that the adaptive substitution HA L226Q rapidly acquired by H9N2 viruses during the course of infection in mice contributed to their high pathogenicity.

Epidemiology, evolution, and biological characteristics of H6 avian influenza viruses in China.

H6 avian influenza virus (AIV) is one of the most prevalent AIV subtypes in birds globally. To investigate the current situation and characteristics of H6 AIVs circulating in China, we analysed the epidemiology, genetic evolution and pathogenic features of this subtype. During 2000-2021, H6 subtype AIVs spread widely through Southern China and presented high host diversity. On analysing 171 H6 viruses isolated during 2009-2021, dynamic reassortments were observed among H6 and other co-circulating AIV subtypes, and these generated a total of 16 different genotypes. A few H6N6 strains possessed L226 and S228 mutations of hemagglutinin (H3 numbering), which may enhance the affinity of H6 viruses to human receptors. H6N6 viruses also exhibited divergent pathogenicity and growth profiles in vivo and in vitro. Some of the H6N6 viruses could infect mice without mammalian adaptation, and even caused death in this species. Therefore, our study demonstrated that the H6 AIVs posed a potential threat to human health and highlighted the urgent need for continued surveillance and evaluation of the H6 influenza viruses circulating in the field.

Panax ginseng Meyer cv. Silvatica phenolic acids protect DNA from oxidative damage by activating Nrf2 to protect HFF-1 cells from UVA-induced photoaging.

ETHNOPHARMACOLOGICAL RELEVANCE: Long-wave ultraviolet A (UVA) causes skin aging by damaging the fine structures of the skin, such as elastic fibers and collagen fibers, through oxidation. Currently, the use of plant extracts to protect skin from photoaging is a popular method. Panax ginseng C.A. Meyer exerts commendable anti-photoaging and antioxidant effects. P. ginseng Meyer cv. Silvatica, also known as forest ginseng (FG), is a type of ginseng cultivated by artificially simulating the growth environment of wild ginseng aged >15 years. However, there are only a few reports on its anti-photoaging effect on the skin caused by UVA stimulation. AIM OF THE STUDY: To investigate whether isolated and extracted FG can inhibit skin photoaging as well as to explore its action mechanism. METHODS: The FG extract (FGE) was obtained from the supernatant of FG after water extraction and alcohol precipitation with the D101 resin. The composition and content of phenolic acids in FGE were determined by high-performance liquid chromatography (HPLC). The MTT assay was performed to detect cell viability. The ratio of SA-ß-GAL-positive cells, CoL-I level, 8-OHdG concentration, MDA, GSH, GPx, SOD, and CAT activity were measured using relevant kits. Furthermore, cell cycle alterations and ROS accumulation were assessed by flow cytometry. The expressions of p53, p21, p16, and Keap1 protein were detected by Western blotting. The Nrf2 translocation was monitored by immunofluorescence staining. RESULTS: The findings revealed that FGE significantly restored UVA injury-induced cell viability, reduced the proportion of SA-ß-GAL-positive cells, and increased the level of CoL-I secretion in a dose-dependent manner, where the main ingredients were chlorogenic acid, protocatechuic acid, salicylic acid, p-hydroxybenzoic acid, vanillic acid, ferulic acid, and caffeic acid. Further studies indicated that this phenolic acid mixture (PAM) could alleviate UVA-induced HFF-1 cell cycle arrest and protect the DNA from oxidative damage caused by UVA stimulation. Moreover, the expressions of cell cycle regulatory proteins p53, p21, and p16 and the accumulation of ROS were inhibited, the translocation of Nrf2 into the nucleus was promoted, the expression of Keap1 protein was inhibited, the activity of intracellular antioxidant indicators GSH, GPx, SOD, and CAT was enhanced, and the expression of malondialdehyde (MDA) was inhibited. CONCLUSIONS: Collectively, our results demonstrated that FG phenolic acids protect DNA from oxidative damage by activating Nrf2 to safeguard the skin from photoaging induced by UVA stimulation.

Structured transverse orbital angular momentum probed by a levitated optomechanical sensor.

The momentum carried by structured light fields exhibits a rich array of surprising features. In this work, we generate transverse orbital angular momentum (TOAM) in the interference field of two parallel and counter-propagating linearly-polarised focused beams, synthesising an array of identical handedness vortices carrying intrinsic TOAM. We explore this structured light field using an optomechanical sensor, consisting of an optically levitated silicon nanorod, whose rotation is a probe of the optical angular momentum, which generates an exceptionally large torque. This simple creation and direct observation of TOAM will have applications in studies of fundamental physics, the optical manipulation of matter and quantum optomechanics.

Creating tunable lateral optical forces through multipolar interplay in single nanowires.

The concept of lateral optical force (LOF) is of general interest in optical manipulation as it releases the constraint of intensity gradient in tightly focused light, yet such a force is normally limited to exotic materials and/or complex light fields. Here, we report a general and controllable LOF in a nonchiral elongated nanoparticle illuminated by an obliquely incident plane wave. Through computational analysis, we reveal that the sign and magnitude of LOF can be tuned by multiple parameters of the particle (aspect ratio, material) and light (incident angle, direction of linear polarization, wavelength). The underlying physics is attributed to the multipolar interplay in the particle, leading to a reduction in symmetry. Direct experimental evidence of switchable LOF is captured by polarization-angle-controlled manipulation of single Ag nanowires using holographic optical tweezers. This work provides a minimalist paradigm to achieve interface-free LOF for optomechanical applications, such as optical sorting and light-driven micro/nanomotors.

Phenolic acids in Panax ginseng inhibit melanin production through bidirectional regulation of melanin synthase transcription via different signaling pathways.

Background: Our previous investigation indicated that the preparation of Panax ginseng Meyer (P. ginseng) inhibited melanogenesis. It comprised salicylic acid (SA), protocatechuic acid (PA), p-coumaric acid (p-CA), vanillic acid (VA), and caffeic acid (CA). In this investigation, the regulatory effects of P. ginseng phenolic acid monomers on melanin production were assessed. Methods: In vitro and in vivo impact of phenolic acid monomers were assessed. Results: SA, PA, p-CA and VA inhibited tyrosinase (TYR) to reduce melanin production, whereas CA had the opposite effects. SA, PA, p-CA and VA significantly downregulated the melanocortin 1 receptor (MC1R), cycle AMP (cAMP), protein kinase A (PKA), cycle AMP-response element-binding protein (CREB), microphthalmia-associated transcription factor (MITF) pathway, reducing mRNA and protein levels of TYR, tyrosinase-related protein 1 (TYRP1), and TYRP2. Moreover, CA treatment enhanced the cAMP, PKA, and CREB pathways to promote MITF mRNA level and phosphorylation. It also alleviated MITF protein level in α-MSH-stimulated B16F10 cells, comparable to untreated B16F10, increasing the expression of phosphorylation glycogen synthase kinase 3ß (p-GSK3ß), ß-catenin, p-ERK/ERK, and p-p38/p38. Furthermore, the GSK3ß inhibitor promoted p-GSK3ß and p-MITF expression, as observed in CA-treated cells. Moreover, p38 and ERK inhibitors inhibited CA-stimulated p-p38/p38, p-ERK/ERK, and p-MITF increase, which had negative binding energies with MC1R, as depicted by molecular docking. Conclusion: P. ginseng roots' phenolic acid monomers can safely inhibit melanin production by bidirectionally regulating melanin synthase transcription. Furthermore, they reduced MITF expression via MC1R/cAMP/PKA signaling pathway and enhanced MITF post-translational modification via Wnt/mitogen-activated protein kinase signaling pathway.

The complex Maxwell stress tensor theorem: The imaginary stress tensor and the reactive strength of orbital momentum. A novel scenery underlying electromagnetic optical forces.

We uncover the existence of a universal phenomenon concerning the electromagnetic optical force exerted by light or other electromagnetic waves on a distribution of charges and currents in general, and of particles in particular. This conveys the appearence of underlying reactive quantities that hinder radiation pressure and currently observed time-averaged forces. This constitutes a novel paradigm of the mechanical efficiency of light on matter, and completes the landscape of the optical, and generally electromagnetic, force in photonics and classical electrodynamics; widening our understanding in the design of both illumination and particles in optical manipulation without the need of increasing the illuminating power, and thus lowering dissipation and heating. We show that this may be accomplished through the minimization of what we establish as the reactive strength of orbital (or canonical) momentum, which plays against the optical force a role analogous to that of the reactive power versus the radiation efficiency of an antenna. This long time overlooked quantity, important for current progress of optical manipulation, and that stems from the complex Maxwell theorem of conservation of complex momentum that we put forward, as well as its alternating flow associated to the imaginary part of the complex Maxwell stress tensor, conform the imaginary Lorentz force that we introduce in this work, and that like the reactive strength of orbital momentum, is antagonistic to the well-known time-averaged force; thus making this reactive Lorentz force indirectly observable near wavelengths at which the time-averaged force is lowered. The Minkowski and Abraham momenta are also addressed.

Ginsenosides repair UVB-induced skin barrier damage in BALB/c hairless mice and HaCaT keratinocytes.

BACKGROUND: Ginsenosides (GS) have potential value as cosmetic additives for prevention of skin photoaging. However, their protective mechanisms against skin barrier damage and their active monomeric constituents are unknown. METHODS: GS monomer types and their relative proportions were identified. A UVB-irradiated BALB/c hairless mouse model was used to assess protective effects of GS components on skin epidermal thickness and transepidermal water loss (TEWL). Skin barrier function, reflected by filaggrin (FLG), involucrin (IVL), claudin-1 (Cldn-1), and aquaporin 3 (AQP3) levels and MAPK phosphorylation patterns, were analyzed in UVB-irradiated hairless mice or HaCaT cells. RESULTS: Total GS monomeric content detected by UPLC was 85.45% and was largely attributed to 17 main monomers that included Re (16.73%), Rd (13.36%), and Rg1 (13.38%). In hairless mice, GS ameliorated UVB-induced epidermal barrier dysfunction manifesting as increased epidermal thickness, increased TEWL, and decreased stratum corneum water content without weight change. Furthermore, GS treatment of UVB-irradiated mice restored protein expression levels and epidermal tissue distributions of FLG, IVL, Cldn-1, and AQP3, with consistent mRNA and protein expression results obtained in UVB-irradiated HaCaT cells (except for unchanging Cldn-1 expression). Mechanistically, GS inhibited JNK, p38, and ERK phosphorylation in UVB-irradiated HaCaT cells, with a mixture of Rg2, Rg3, Rk3, F2, Rd, and Rb3 providing the same protective MAPK pathway inhibition-associated upregulation of IVL and AQP3 expression as provided by intact GS treatment. CONCLUSION: GS protection against UVB-irradiated skin barrier damage depends on activities of six ginsenoside monomeric constituents that inhibit the MAPK signaling pathway.