Polarization-insensitive and high-efficiency edge coupler for thin-film lithium niobate.

In this Letter, we propose and demonstrate a fiber-to-chip edge coupler (EC) on an x-cut thin film lithium niobate (TFLN) for polarization-insensitive (PI) coupling. The EC consists of three width-tapered full-etched waveguides with silica cladding and matches well with a single-mode fiber (SMF). The measured results show that the minimum coupling losses for TE0/TM0 modes remain to be 0.9 dB/1.1 dB per facet, and the polarization dependent loss (PDL) is <0.5 dB over the wavelength range from 1260 to 1340 nm. Moreover, the EC features large misalignment tolerance of ±2 µm in the Z direction and ±1.5 µm in the X direction for both polarizations for a 1 dB penalty. To the best of our knowledge, this is the first realized O-band edge coupler on TFLN with SMF. The proposed device shows promising potential for integration into TFLN polarization diversity devices.

High performance polarizer on thin-film lithium niobate with width-tapered Euler bending.

In this Letter, we propose and demonstrate an integrated polarizer on thin film lithium niobate (TFLN). The polarizer consists of a width-tapered 180° Euler bending waveguide featuring thin thickness and bilevel mode convertors with silica cladding. Notably, the TE0 mode is efficiently confined in the waveguide, while the TM0 mode confronts significant bending losses. The measurements reveal that the excess loss remains below 1.5 dB, and the extinction ratio surpasses 19 dB within a working bandwidth spanning from 1480 to 1578 nm. The proposed polarizer holds considerable promise for enhancing polarization handling within TFLN photonic circuits.

Ultra-compact electro-optic modulator based on etchless lithium niobate photonic crystal nanobeam cavity.

Photonic crystal (PhC) cavities with high Q factor and low volume have been applied in nonlinear, electro-optic and acoustic-optic devices due to the enhancement of the light-matter interactions. However, there are few devices and research on LiNbO3 (LN) PhC cavities due to the difficulty in making hyperfine structures on LN platform. In this work, we propose a PhC nanobeam cavity on the etchless x-cut LiNbO3-On-Insulator (LNOI). The fabrication-friendly device has been designed based on photonic bound states in the continuum (BICs) exhibiting a high Q factor of over 10,000 with the device length of only about 100 µm. Utilizing the electro-optical effect γ13 of LN, we demonstrate an ultra-compact electro-optic modulator based on the PhC nanobeam cavities, which has the modulation efficiency of 1.5 pm/V and the 3 dB bandwidth of 28 GHz.

Association of Toll-like Receptor 4 Rs7873784 G/C Polymorphism with Rheumatoid Arthritis Risk in a Chinese Population.

BACKGROUND: The purposes of this study were to explore whether the Toll-like receptor 4 (TLR4) gene rs7873784 G/C polymorphism was related to the risk of rheumatoid arthritis (RA) and to the clinical features of the disease in Chinese subjects. MATERIALS AND METHODS: We examined the TLR4 rs7873784 G/C polymorphism in 805 Chinese RA patients and 1095 healthy controls. Genotype was determined with a custom-by-design 48-Plex single nucleotide polymorphism scan™ Kit. Blood plasma levels of TLR4 in 170 RA patients and 170 matched controls were measured by ELISA. RESULTS: The TLR4 gene rs7873784 G/C polymorphism was related to a reduced risk for RA. By stratified analysis, we found a dramatically reduced risk for RA in patients who were female, CRP-positive, RF-positive, DAS28 ≥ 3.20, or ESR ≥ 25. Compared with the controls, the average level of TLR4 protein in plasma of RA patients was increased. In addition, RA patients exhibited higher levels of TLR4 mRNA than controls (P < .05). CONCLUSION: These results demonstrate the TLR4 rs7873784 G/C polymorphism to relate to a decreased risk for RA in a Chinese population.

Standardized Pomegranate (Pomella®) and Red Maple (Maplifa®) Extracts and Their Phenolics Protect Type I Collagen by the Inhibition of Matrix Metalloproteinases, Collagenase, and Collagen Cross-Linking.

Phenolics enriched pomegranate fruit (Pomella®) and red maple leaf (Maplifa®) extracts and their major phenolic constituents have demonstrated beneficial skin effects through the protection of human skin keratinocytes from oxidative-stress-induced damage. However, their mechanisms of protection of cutaneous collagen are still unclear. Herein, the collagen protective effects of Pomella® and Maplifa®, and their major bioactive phytochemicals, namely, punicalagin (PA) and ginnalin A (GA), respectively, were evaluated using enzymatic assays including collagenase, anti-glycation and cell-based models as well as computational methods. The importance of the modulatory effects was validated at the protein level for type I collagen and matrix metalloproteinases (MMPs) using human-skin-derived keratinocytes. The synergistic collagenase inhibitory effects upon combinations of Pomella® + Maplifa® and PA + GA at a combination ratio of 1:2 and 1:1, respectively, were evaluated using their combination index (CI; a well-established assessment of synergism). Pomella® (50-400 µg/mL), Maplifa® (100-800 µg/mL), PA (50-400 µM), and GA (50-400 µM) dose-dependently inhibited collagenase activity by 26.3-86.3%, 25.7-94.0%, 26.2-94.0%, and 12.0-98.0%, respectively. The CI of the anti-collagenase activity of Pomella® and Maplifa® ranged from 0.53-0.90, while that of PA and GA (12.5/12.5 and 25/25 µM) ranged from 0.66 and 0.69, respectively, suggesting a synergistic inhibitory effect. Interestingly, in the cell-based assays by Western blotting, Pomella® and Maplifa® reduced the protein expression levels of collagen degradation enzymes (MMPs), while simultaneously increasing that of type I collagen in epidermoid carcinoma A431 cells. This is the first report to show that these extracts exert synergistic collagen protective effects. Taken together, these findings provide molecular insights into the usefulness of Pomella® and Maplifa® or their phenolics as bioactive ingredients for skin care products to slow down aging and enhance skin tone.

Has previous loan rejection scarred firms from applying for loans during Covid-19?

Abstract: The concept of the 'discouraged' borrower is well documented. In this paper, we consider whether smaller firms in the UK who have been previously rejected for bank loans have been scarred by the experience so badly that even in the presence of two exceptionally generous Covid-19 loan guarantee schemes, they still refuse to make an application. Furthermore, we also consider what happens when they do. As banks have either zero or minimal loss exposure, do they still maintain their normal strict lending protocols or do they relax their standards to fulfil the governments' objective of supporting struggling businesses through the crisis? Our findings show that 72% of previously rejected borrowers are reluctant to request loans. We find some evidence that previously scarred firms faced such severe liquidity problems that they relaxed their distrust of banks during the Covid-19 crisis. However, their share of the government-guaranteed loan portfolio was slightly lower suggesting that banks were treating each new loan application on its merits. Plain English Summary: The Covid-19 crisis hit smaller businesses so hard that even previously rejected borrowers were forced to apply for loans to keep them afloat. Previous loan rejections have not discouraged small businesses in the UK in applying for Covid-19 government-guaranteed loans. Banks have used the loan guarantee schemes to continue to supply loans to small business during the pandemic. Our paper analyses the important phenomenon of borrower scarring and discouragement, when potential debtors are self-excluded from the lending market because they have previous rejections or expect a negative bank response. We consider around 45,000 UK small businesses from 2018 to 2020. On the demand side, we find that the economic shock for small businesses during the pandemic dissipates the scarring effect. Specifically, we find that micro and small businesses had the highest loan demand in the first two quarters of the pandemic (from March 2020). On the supply side, we show that scarred borrowers were not routed onto Covid-19 government-guaranteed loan schemes. These findings show the importance of government-backed lending schemes for small businesses during crisis period. Supplementary Information: The online version contains supplementary material available at 10.1007/s11187-021-00586-2.

High-performance all-silicon polarizer with 415 nm bandwidth.

On-chip silicon polarizers have been widely used in polarization controllers. However, there is limited research on all-silicon polarizer covering the whole optical communication band due to the strong waveguide dispersion for silicon waveguides. In this Letter, we demonstrated an all-silicon TE polarizer with high polarization extinction ratio and low insertion loss, working for the whole optical communication band. The device is based on a shallow-etched waveguide realized on a silicon-on-insulator (SOI) platform. The optical field of TE polarization is designed to be tightly confined in the shallow-etched silicon waveguide, while that of TM polarization is weakly confined. As a result, TE polarization propagates through the waveguide with low loss, while TM polarization leaks into the substrate and decays finally. The measurements show that a maximum insertion loss <0.25dB and polarization extinction ratio (PER)>20dB over an ultrabroad operation band from 1260-1675 nm have been achieved for the proposed polarizer.

Associations of the IL-1B level, IL-1A and IL-1B gene polymorphisms and ankylosing spondylitis risk in a Chinese Han population.

INTRODUCTION: The aim of this study was to investigate the effect of interleukin (IL)-1A and IL-1B gene polymorphisms on ankylosing spondylitis (AS) susceptibility in a Chinese population. Additionally, we examined the association of IL-1B level with different genotype of rs2853550 polymorphism and clinicopathological features of AS patients. MATERIALS AND METHODS: The IL-1B concentration in plasma was determined by an enzyme-linked immunosorbent assay. The IL-1A rs3783546, IL-1A rs3783550 and IL-1B rs2853550 gene polymorphisms were determined by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. RESULTS: Our data indicated that the average plasma IL-1B concentration in the AS patients was markedly higher than in the control samples. Subgroup analyses suggested that there was no significant association between plasma IL-1B concentration and sex, age, HLA-B27, C-reactive protein (CRP), or grade of the sacroiliac joint in AS patients. We also found that the IL-1B rs2853550 AG genotype showed significantly correlation with an increased risk of AS. In comparing AS patients to control participants, elevated plasma concentrations were observed in AS patients while significant differences were found between the IL-1B rs2853550 AA genotypes. There is a negative correlation between the IL-1A rs3783550 and IL-1A rs3783546 polymorphisms in the AS patients in relation to controls. CONCLUSIONS: The IL-1B concentration in plasma was markedly higher in cases and AA genotype carriers. Furthermore, IL-1B rs2853550 AG was a genetic contributor to AS risk in a Chinese population.

Evaluation of Polyphenol Anthocyanin-Enriched Extracts of Blackberry, Black Raspberry, Blueberry, Cranberry, Red Raspberry, and Strawberry for Free Radical Scavenging, Reactive Carbonyl Species Trapping, Anti-Glycation, Anti-ß-Amyloid Aggregation, and Microglial Neuroprotective Effects.

Glycation is associated with several neurodegenerative disorders, including Alzheimer's disease (AD), where it potentiates the aggregation and toxicity of proteins such as ß-amyloid (Aß). Published studies support the anti-glycation and neuroprotective effects of several polyphenol-rich fruits, including berries, which are rich in anthocyanins. Herein, blackberry, black raspberry, blueberry, cranberry, red raspberry, and strawberry extracts were evaluated for: (1) total phenolic and anthocyanins contents, (2) free radical (DPPH) scavenging and reactive carbonyl species (methylglyoxal; MGO) trapping, (3) anti-glycation (using BSA-fructose and BSA-MGO models), (4) anti-Aß aggregation (using thermal- and MGO-induced fibrillation models), and, (5) murine microglia (BV-2) neuroprotective properties. Berry crude extracts (CE) were fractionated to yield anthocyanins-free (ACF) and anthocyanins-enriched (ACE) extracts. The berry ACEs (at 100 µg/mL) showed superior free radical scavenging, reactive carbonyl species trapping, and anti-glycation effects compared to their respective ACFs. The berry ACEs (at 100 µg/mL) inhibited both thermal- and MGO-induced Aß fibrillation. In addition, the berry ACEs (at 20 µg/mL) reduced H2O2-induced reactive oxygen species production, and lipopolysaccharide-induced nitric oxide species in BV-2 microglia as well as decreased H2O2-induced cytotoxicity and caspase-3/7 activity in BV-2 microglia. The free radical scavenging, reactive carbonyl trapping, anti-glycation, anti-Aß fibrillation, and microglial neuroprotective effects of these berry extracts warrant further in vivo studies to evaluate their potential neuroprotective effects against AD.

High sensitivity visible light refractive index sensor based on high order mode Si3N4 photonic crystal nanobeam cavity.

We design and demonstrate a suspended high sensitivity silicon nitride (Si3N4) photonic crystal (PhC) nanobeam cavity sensor. By utilizing the higher order mode, the optical field distribution in the analytes increases dramatically and the light matter interaction between the optical mode and the analytes has been enhanced. A high sensitivity of 321 nm/refractive index unit (nm/RIU) has been experimentally achieved at the wavelength ~700 nm which is the highest value reported so far for a resonator based sensor at such a short wavelength.

Polarization-insensitive broadband 2 × 2 3 dB power splitter based on silicon-bent directional couplers.

We present and demonstrate a broadband and polarization-insensitive 2×2 3 dB power splitters based on silicon-bent directional couplers (DCs). The working bandwidth can be from 1520 to 1630 nm for both TE and TM polarizations, with an excess loss less than 1 dB. The total size for the fabricated device can be as small as 50 µm, and the measurement results show good agreement with the simulations.

High sensitivity temperature sensor based on cascaded silicon photonic crystal nanobeam cavities.

We present the design, fabrication and characterization of a high sensitivity temperature sensor based on cascaded silicon photonic crystal (PhC) nanobeam cavities. Two PhC nanobeam cavities, one with stack width modulated structure and the other one with parabolic-beam structure are utilized to increase the sensitivity. Most of the light is designed to be confined in the cladding and the core for these two cavities, respectively. Due to the positive thermo-optic (TO) coefficient of silicon and the negative TO coefficient of SU-8 cladding, the wavelength responses red shift for parabolic-beam cavity and blue shift for stack width modulated cavity as the increase of the ambient temperature, respectively. Thus, the sensitivity for the temperature sensor can be improved greatly since the difference in resonant wavelength shifts is detected for the temperature sensing. The experimental results show that the sensitivity of the temperature sensor is about 162.9 pm/°C, which is almost twice as high as that of the conventional silicon based resonator sensors.

Effects of a Standardized Phenolic-Enriched Maple Syrup Extract on ß-Amyloid Aggregation, Neuroinflammation in Microglial and Neuronal Cells, and ß-Amyloid Induced Neurotoxicity in Caenorhabditis elegans.

Published data supports the neuroprotective effects of several phenolic-containing natural products, including certain fruit, berries, spices, nuts, green tea, and olive oil. However, limited data are available for phenolic-containing plant-derived natural sweeteners including maple syrup. Herein, we investigated the neuroprotective effects of a chemically standardized phenolic-enriched maple syrup extract (MSX) using a combination of biophysical, in vitro, and in vivo studies. Based on biophysical data (Thioflavin T assay, transmission electron microscopy, circular dichroism, dynamic light scattering, and zeta potential), MSX reduced amyloid ß1-42 peptide (Aß1-42) fibrillation in a concentration-dependent manner (50-500 µg/mL) with similar effects as the neuroprotective polyphenol, resveratrol, at its highest test concentration (63.5 % at 500 µg/mL vs. 77.3 % at 50 µg/mL, respectively). MSX (100 µg/mL) decreased H2O2-induced oxidative stress (16.1 % decrease in ROS levels compared to control), and down-regulated the production of lipopolysaccharide (LPS)-stimulated inflammatory markers (22.1, 19.9, 74.8, and 87.6 % decrease in NOS, IL-6, PGE2, and TNFα levels, respectively, compared to control) in murine BV-2 microglial cells. Moreover, in a non-contact co-culture cell model, differentiated human SH-SY5Y neuronal cells were exposed to conditioned media from BV-2 cells treated with MSX (100 µg/mL) and LPS or LPS alone. MSX-BV-2 media increased SH-SY5Y cell viability by 13.8 % compared to media collected from LPS-BV-2 treated cells. Also, MSX (10 µg/mL) showed protective effects against Aß1-42 induced neurotoxicity and paralysis in Caenorhabditis elegans in vivo. These data support the potential neuroprotective effects of MSX warranting further studies on this natural product.

NADH plays the vital role for chiral pure D-(-)-2,3-butanediol production in Bacillus subtilis under limited oxygen conditions.

Compared with traditional pathogenic producers, Bacillus subtilis as a Class I microorganism offers many advantages for industrial-scale 2,3-butanediol production. Unlike previous reports in which two stereoisomers (with a ratio of 3:2) were produced, we first found that wild type B. subtilis 168 generates only D-(-)-2,3-butanediol (purity >99%) under low oxygen conditions. The total high yield of 2,3-butanediol and acetoin, and acetoin reductase enzyme assay indicate that it is the high level of NADH availability, instead of high acetoin reductase activity, contributes more to 2,3-butanediol production in B. subtilis. The strategy for increasing the pool of NADH availability, the key factor for 2,3-butanediol production, was designed through low dissolved oxygen control, adding reducing substrates and rationally metabolic engineering. A transhydrogenase encoded by udhA was introduced to provide more NADH from NADPH and allowed enhanced 2,3-butanediol production. Finally, BSF20 produced 49.29 g/L D(-)-2,3-butanediol. These results demonstrated that B. subtilis is a competitive producer for chiral 2,3-butanediol production.

Fengshi Liuhe Decoction treatment for rheumatoid arthritis via the Fzd6/NF-κB signaling axis.

To explore whether Fengshi Liuhe Decoction (FLD) alleviates rheumatoid arthritis (RA) via the Fzd6/NF-κB signaling axis. We used real-time quantitative PCR (qPCR) and western blotting (WB) to determine the genes of the frizzled (Fzd) protein 1- Fzd protein 10 that are significantly differentially expressed between normal rat fibroblast-like synoviocyte (FLS) and collagen II-induced arthritis (CIA) rat FLS. Next, we used enzyme-linked immunosorbent assay (ELISA) to evaluate the levels of inflammatory factors in cell culture supernatant to determine the ability of FLD to ameliorate RA. Finally, we employed WB to detect the key gene expression in protein levels of the Fzd6/NF-κB signaling axis among normal rat FLS, CIA rat FLS, and FLD-treated CIA rat FLS. Our results showed that Fzd6 expression was significantly higher in CIA rat FLS at both the mRNA and protein levels than in normal rat FLS. FLD was found to downregulate Fzd6 and inflammatory factors, including COX-2, IL-8, and TNF-α, at both the mRNA and protein levels. FLD was also found to downregulate the total protein levels of Fzd6 and the NF-κB signaling pathway key gene phosphorylation of p-p65/p65 and p-IκBα/IκBα. Moreover, FLD inhibited the nuclear translocation of NF-κB p65 in CIA rat FLS. FLD can alleviate inflammation of CIA rat FLS via the Fzd6/NF-κB signaling axis.

Non-enzymatic glycation of melamine with sugars and sugar like compounds.

Melamine (1,3,5-triazine-2,4,6-triamine) is employed in the manufacture of plastics, laminates and glues, yet, it has been found sometimes added illegally to dairy products to artificially inflate foods' protein content. In 2008, dairy products adulterated with melamine were blamed for the death of several infants in China, a situation that forced Beijing to introduce stricter food safety measures. The objectives of this study were threefold: (1) to investigate the susceptibility of the amine groups of melamine to glycation with D-galactose, D-glucose and lactose, sugars commonly found in milk, (2) to study the rate and extent of melamine's glycation with methylglyoxal, glyoxal and DL-glyceraldehyde, three highly reactive metabolites of D-galactose, D-glucose and lactose, and (3) to characterize, using mass spectrometry, the Advanced Glycation Endproducts (AGEs) of melamine with sugars found commonly in milk and their metabolites. Incubation of D-galactose, D-glucose and lactose with melamine revealed that D-galactose was the most potent glycator of melamine, followed by D-glucose, then lactose. Methylglyoxal, glyoxal, and DL-glyceraldehyde glycated melamine more extensively than D-galactose, with each yielding a broader range of AGEs. The non-enzymatic modification of melamine by sugars and sugar-like compounds warrants further investigation, as this process may influence melamine's toxicity in vivo.

Clinical outcomes of unilateral biportal endoscopic lumbar interbody fusion (ULIF) compared with conventional posterior lumbar interbody fusion (PLIF).

BACKGROUND CONTEXT: In recent years, unilateral biportal endoscopic lumbar interbody fusion (ULIF) has been more and more favored by spinal surgeons because of its advantages of low trauma, rapid recovery, high fusion rate and fewer complications. PURPOSE: To compare the clinical effects of ULIF with those of conventional open posterior lumbar interbody fusion (PLIF). STUDY DESIGN: Prospective case control study. PATIENT SAMPLE: Twenty-seven patients treated by ULIF and thirty-three patients treated by PLIF. OUTCOME MEASURES: The preoperative baseline and surgical technique-related outcomes (mean operation time, blood loss during operation, postoperative drainage, and postoperative hospital stay) were compared between the two groups. The clinical status of the two groups before and after surgery were also compared: visual analogue scale (VAS) score of the legs and back, Japanese Orthopedic Association (JOA) score and Oswestry Disability Index (ODI). The clinical laboratory indexes of the two groups before and after the operation were compared: C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), creatine phosphokinase (CPK), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), as well as the incidence of complications, such as dural tear, nerve root injury and infection. METHODS: Adult patients who underwent L3-S1 single level lumbar interbody fusion were included in the study. They were divided into a PLIF group and a ULIF group according to the type of surgery. This study comprised 60 cases: 27 cases in the ULIF group and thirty-three cases in the PLIF group. RESULTS: There was no significant difference in preoperative baseline between the two groups. The ULIF group experienced less blood loss, postoperative drainage and a shorter postoperative hospital stay than the PLIF group; however the ULIF group required a longer operation time than the PLIF group (p<.05). CRP, ESR, CPK, IL-6, and TNF-α levels of the PLIF group were all significantly higher than those of the ULIF group 5 days after surgery (p<.05). The improvements in the VAS scores for back pain, VAS scores for leg pain and JOA score in the ULIF group were all significantly better than those in the PLIF group at 5 days after surgery (p<.05). There was no significant difference in fusion rate at 6 months between the 2 groups (p>.05). CONCLUSIONS: This study showed that ULIF and PLIF were both effective surgical techniques for lumbar interbody fusion. However, ULIF caused less bleeding, reduced inflammatory reaction, less tissue damage and faster postoperative recovery compared with PLIF. Both long-term follow-up and larger clinical studies are needed to validate the clinical and radiological results of this surgery.

All-organic polymeric materials with high refractive index and excellent transparency.

High refractive index polymers (HRIPs) have drawn attention for their optoelectronic applications and HRIPs with excellent transparency and facile preparation are highly demanded. Herein, sulfur-containing all organic HRIPs with refractive indices up to 1.8433 at 589 nm and excellent optical transparency even in one hundred micrometre scale in the visual and RI region as well as high weight-average molecular weights (up to 44500) are prepared by our developed organobase catalyzed polymerization of bromoalkynes and dithiophenols in yields up to 92%. Notably, the fabricated optical transmission waveguides using the resultant HRIP with the highest refractive index display a reduced propagation loss compared with that generated by the commercial material of SU-8. In addition, the tetraphenylethylene containing polymer not only exhibits a reduced propagation loss, but also is used to examine the uniformity and continuity of optical waveguides with naked eyes because of its aggregation-induced emission feature.

Identification and quantification of the combined phytotoxicity of one element with various valences: Cr(III) and Cr(VI) for barley root elongation as an example.

There is uncertainty in quantifying the toxic effects of total chromium (Cr) in the environment by modeling the toxicity of individual Cr(III) or Cr(VI). In the present study, the effects of Cr(III) and Cr(VI) on barley root elongation were investigated in a hydroponic system where Cr(III) and Cr(VI) combination dose-response experiments under monotoxicity concentration, single-dose addition, and fixed concentration ratios were designed to identify and quantify their combined phytotoxicity of one element with various valences. The results show that the calculated mixed toxicity unit values for 50% inhibition (TUmix50) ranged from 1.06 to 1.45, indicating the weak antagonism effects of Cr(III) and Cr(VI) on barley root toxicity. Also, the single-dose group experiment has proved that the EC50 of Cr(VI) was increased from 71.2 µM to 119.9 µM with Cr(III) addition, which suggested that Cr(III) has antagonism on the toxicity of Cr(VI). While EC50 of Cr(III) was not affected by Cr(VI) addition. After introducing the expansion coefficient of Cr(III) on Cr(VI) toxicity, both the extended concentration addition model (e-CA) based on the log-logistic and Weibull equations and the extended independent action model (e-IA) could more accurately predict the barley root elongation under Cr(III) and Cr(VI) interaction. The e-CA model based on the Weibull equation had almost the best correlation coefficient (R2) and lowest root mean square error (RMSE) between the measured and predicted values. Finally, the combined toxicity and antagonism of the same element with co-existing different valences simultaneously were successfully and firstly identified and quantified in the present study.

Photonic-circuited resonance fluorescence of single molecules with an ultrastable lifetime-limited transition.

Resonance fluorescence as the emission of a resonantly-excited two-level quantum system promises indistinguishable single photons and coherent high-fidelity quantum-state manipulation of the matter qubit, which underpin many quantum information processing protocols. Real applications of the protocols demand high degrees of scalability and stability of the experimental platform, and thus favor quantum systems integrated on one chip. However, the on-chip solution confronts several formidable challenges compromising the scalability prospect, such as the randomness, spectral wandering and scattering background of the integrated quantum systems near heterogeneous and nanofabricated material interfaces. Here we report an organic-inorganic hybrid integrated quantum photonic platform that circuits background-free resonance fluorescence of single molecules with an ultrastable lifetime-limited transition. Our platform allows a collective alignment of the dipole orientations of many isolated molecules with the photonic waveguide. We demonstrate on-chip generation, beam splitting and routing of resonance-fluorescence single photons with a signal-to-background ratio over 3000 in the waveguide at the weak excitation limit. Crucially, we show the photonic-circuited single molecules possess a lifetime-limited-linewidth transition and exhibit inhomogeneous spectral broadenings of only about 5% over hours' measurements. These findings and the versatility of our platform pave the way for scalable quantum photonic networks.