Heterogeneous sapphire-supported low-loss photonic platform.

Sapphire is a promising wideband substrate material for visible photonics. It is a common growth substrate for III-nitride light-emitting diodes and laser structures. Doped sapphires are important gain media foundational to the development of titanium-sapphire and ruby lasers. For lasers operating at visible and near-infrared wavelengths, a photonic platform that minimizes loss while maximizing gain material overlap is crucial. Here, we introduce a novel low-loss waveguiding strategy that establishes high-performance integrated photonics on sapphire substrates. This platform achieves a high intrinsic quality factor of 5.6 million near 780 nm and features direct compatibility with a range of solid-state laser gain media.

Serum fibroblast growth factor-2 levels complement vital biomarkers for diagnosing heart failure.

BACKGROUND: Early diagnosis of atrial fibrillation is important as it is crucial for improving patient outcomes. Fibroblast growth factor-2 (FGF2) may serve as a diagnostic biomarker for heart failure due to its ability to promote cardiac fibrosis and hypertrophy; however, the relationship between FGF2 concentration and heart failure is unclear. Therefore, this study aimed to explore whether FGF2 could aid in distinguishing patients with heart failure from healthy controls and those with dyspnea without heart failure. Additionally, to evaluate the possible correlation between serum FGF2 levels and its diagnostic parameters in patients with heart failure. METHODS: Plasma FGF2 concentration was measured in 114 patients with a complaint of dyspnea (enrolled in the study between January 2022 and August 2022). Based on heart failure diagnosis, the patients were assigned to three groups, as follows: heart failure (n = 80), non-heart-failure dyspnea (n = 34), and healthy controls (n = 36), following physical examination. Possible correlations between serum FGF2 levels and other prognostic parameters in patients with heart failure were analyzed. RESULTS: Serum FGF2 levels were higher in patients with heart failure (125.60 [88.95, 183.40] pg/mL) than in those with non-heart-failure dyspnea (65.30 [28.85, 78.95] pg/mL) and healthy controls (78.90 [60.80, 87.20] pg/mL) (p < 0.001). Receiver operating characteristic curve analysis identified FGF2 concentration as a significant predictor in heart failure diagnosis, with an area under the curve of 0.8693 (p < 0.0001). Importantly, in the heart failure group, serum FGF2 concentrations correlated with key prognostic parameters for heart failure, such as reduced left ventricular ejection fraction and elevated serum levels of N-terminal pro-B-type natriuretic peptide. CONCLUSIONS: Elevated serum FGF2 level is strongly associated with an increased risk of heart failure and could serve as a useful biomarker to complement vital diagnostic parameters for heart failure.

T2-FLAIR mismatch sign and machine learning-based multiparametric MRI radiomics in predicting IDH mutant 1p/19q non-co-deleted diffuse lower-grade gliomas.

AIM: To investigate the application of the T2-weighted (T2)-fluid-attenuated inversion recovery (FLAIR) mismatch sign and machine learning-based multiparametric magnetic resonance imaging (MRI) radiomics in predicting 1p/19q non-co-deletion of lower-grade gliomas (LGGs). MATERIALS AND METHODS: One hundred and forty-six patients, who had pathologically confirmed isocitrate dehydrogenase (IDH) mutant LGGs were assigned randomly to the training cohort (n=102) and the testing cohort (n=44) at a ratio of 7:3. The T2-FLAIR mismatch sign and conventional MRI features were evaluated. Radiomics features extracted from T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), FLAIR, apparent diffusion coefficient (ADC), and contrast-enhanced T1WI images (CE-T1WI). The models that displayed the best performance of each sequence were selected, and their predicted values as well as the T2-FLAIR mismatch sign data were collected to establish a final stacking model. Receiver operating characteristic curve (ROC) analyses and area under the curve (AUC) values were applied to evaluate and compare the performance of the models. RESULTS: The T2-FLAIR mismatch sign was more common in the IDH mutant 1p/19q non-co-deleted group (p<0.05) and the area under the curve (AUC) value was 0.692 with sensitivity 0.397, specificity 0.987, and accuracy 0.712, respectively. The stacking model showed a favourable performance with an AUC of 0.925 and accuracy of 0.882 in the training cohort and an AUC of 0.886 and accuracy of 0.864 in the testing cohort. CONCLUSION: The stacking model based on multiparametric MRI can serve as a supplementary tool for pathological diagnosis, offering valuable guidance for clinical practice.

Age effect on the shared etiology of glycemic traits and serum lipids: evidence from a Chinese twin study.

PURPOSE: Diabetes and dyslipidemia are among the most common chronic diseases with increasing global disease burdens, and they frequently occur together. The study aimed to investigate differences in the heritability of glycemic traits and serum lipid indicators and differences in overlapping genetic and environmental influences between them across age groups. METHODS: This study included 1189 twin pairs from the Chinese National Twin Registry and divided them into three groups: aged ≤ 40, 41-50, and > 50 years old. Univariate and bivariate structural equation models (SEMs) were conducted on glycemic indicators and serum lipid indicators, including blood glucose (GLU), glycated hemoglobin A1c (HbA1c), total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C), in the total sample and three age groups. RESULTS: All phenotypes showed moderate to high heritability (0.37-0.64). The heritability of HbA1c demonstrated a downward trend with age (HbA1c: 0.50-0.79), while others remained relatively stable (GLU: 0.55-0.62, TC: 0.58-0.66, TG: 0.50-0.63, LDL-C: 0.24-0.58, HDL-C: 0.31-0.57). The bivariate SEMs demonstrated that GLU and HbA1c were correlated with each serum lipid indicator (0.10-0.17), except HDL-C. Except for HbA1c and LDL-C, as well as HbA1c and HDL-C, differences in genetic correlations underlying glycemic traits and serum lipids between age groups were observed, with the youngest group showing a significantly higher genetic correlation than the oldest group. CONCLUSION: Across the whole adulthood, genetic influences were consistently important for GLU, TC, TG, LDL-C and HDL-C, and age may affect the shared genetic influences between glycemic traits and serum lipids. Further studies are needed to elucidate the role of age in the interactions of genes related to glycemic traits and serum lipids.

Ultra-high Q alumina optical microresonators in the UV and blue bands.

UV and visible photonics enable applications ranging from spectroscopic sensing to communication and quantum information processing. Photonics structures in these wavelength regimes, however, tend to experience higher loss than their IR counterpart. Particularly in the near-UV band, on-chip optical microresonators have not yet achieved a quality factor beyond 1 million. Here, we report ultra-low-loss photonic waveguides and resonators patterned from alumina thin films prepared by a highly scalable atomic layer deposition process. We demonstrate ultra high Q factor of 1.5×106 at 390 nm, a record value at UV bands, and 1.9×106 at 488.5 nm.

[Study of the predictive role of serum HBV RNA on HBeAg serological conversion in children with chronic hepatitis B].

Objective: To investigate the role of serum hepatitis B virus RNA (HBV RNA) in predicting HBeAg serological conversion in children with chronic hepatitis B. Methods: 175 children aged 1~17 years with chronic hepatitis B who received interferon α (IFNα) for 48 weeks were selected. Patients were divided into HBeAg seroconversion and non-conversion based on whether HBeAg seroconversion occurred at 48 weeks of treatment.T-test and Mann-Whitney U test were used to compare between groups; chisquare test or Fisher exact probability method was used to compare the frequency between groups of classified variables; and Pearson correlation was used to analyze the correlation between indicators. Univariate and multivariate logistic regression analyses were used to identify influencing factors associated with HBeAg serological conversion. The predictive effect of HBV RNA, HBV DNA, and HBsAg on HBeAg serological conversion was compared and analyzed by the receiver operating characteristic curve (ROC). Results: The seroconversion rate of HBeAg at 48 weeks was 36.0% (63/175). The reduction in HBVRNA levels from baseline to the 12th, 24th, 36th, and 48th weeks of antiviral therapy was significantly greater in the HBeAg serological conversion group than that in the non-conversion group, and the difference was statistically significant between the two groups (P < 0.05). Univariate and multivariate regression analyses showed that age and a decline in HBV RNA levels at week 12 were independent predictors of HBeAg serological conversion. The area under the ROC curve (AUROC) of HBV RNA decline at week 12 was 0.677(95% CI∶0.549-0.806, P = 0.012), which was significantly better than the same period of AUROC of HBV DNA (0.657, 95% CI∶0.527-0.788, P = 0.025) and HBsAg (0.660, 95% CI∶0.526-0.795, P = 0.023) decline. HBV RNA levels decreased (>1.385 log10 copies/ml) at week 12, with a positive predictive value of 53.2%, a negative predictive value of 72.2%, a sensitivity of 77.4%, and a specificity of 57.9% for HBeAg seroconversion. Conclusion: HBV RNA level lowering during the 12th week of antiviral therapy can serve as an early predictor marker for HBeAg serological conversion in children with chronic hepatitis B.

Quadratic strong coupling in AlN Kerr cavity solitons.

Photonic platforms with χ(2) nonlinearity offer new degrees of freedom for Kerr frequency comb development. Here, we demonstrate Kerr soliton generation at 1550 nm with phase-matched quadratic coupling to the 775 nm harmonic band in a single AlN microring and thus the formation of dual-band mode-locked combs. In the strong quadratic coupling regime where the χ(2) phase-matching window overlaps the pump mode, the pump-to-harmonic-comb conversion efficiency is optimized. However, the strong quadratic coupling also drastically modifies the Kerr comb generation dynamics and decreases the probability of soliton generation. By engineering the χ(2) phase-matching wavelength, we are able to achieve a balance between high conversion efficiency and high soliton formation rate under the available pump power and microring quality factors. Our numerical simulations confirm the experimental observations. These findings provide guidance on tailoring single-cavity dual-band coherent comb sources.

Unambiguous Experimental Verification of Linear-in-Temperature Spinon Thermal Conductivity in an Antiferromagnetic Heisenberg Chain.

The everlasting interest in spin chains is mostly rooted in the fact that they generally allow for comparisons between theory and experiment with remarkable accuracy, especially for exactly solvable models. A notable example is the spin-1/2 antiferromagnetic Heisenberg chain (AFHC), which can be well described by the Tomonaga-Luttinger liquid theory and exhibits fractionalized spinon excitations with distinct thermodynamic and spectroscopic experimental signatures consistent with theoretical predictions. A missing piece, however, is the lack of a comprehensive understanding of the spinon heat transport in AFHC systems, due to difficulties in its experimental evaluation against the backdrop of other heat carriers and complex scattering processes. Here we address this situation by performing ultralow-temperature thermal conductivity measurements on a nearly ideal spin-1/2 AFHC system copper benzoate Cu(C_{6}H_{5}COO)_{2}·3H_{2}O, whose field-dependent spin excitation gap enables a reliable extraction of the spinon thermal conductivity κ_{s} at zero field. κ_{s} was found to exhibit a linear temperature dependence κ_{s}∼T at low temperatures, with κ_{s}/T as large as 1.70 mW cm^{-1} K^{-2}, followed by a precipitate decline below ∼0.3 K. The observed κ_{s}∼T clarifies the discrepancies between various spin chain systems and serves as a benchmark for one-dimensional spinon heat transport in the low-temperature limit. The abrupt loss of κ_{s} with no corresponding anomaly in the specific heat is discussed in the context of many-body localization.

Superconducting Cavity Electromechanics: The Realization of an Acoustic Frequency Comb at Microwave Frequencies.

We present a nonlinear multimode superconducting electroacoustic system, where the interplay between superconducting kinetic inductance and piezoelectric strong coupling establishes an effective Kerr nonlinearity among multiple acoustic modes at 10 GHz that could hardly be achieved via intrinsic mechanical nonlinearity. By exciting this multimode Kerr system with a single microwave tone, we further demonstrate a coherent electroacoustic frequency comb and provide theoretical understanding of multimode nonlinear interaction in the superstrong coupling limit. This nonlinear superconducting electroacoustic system sheds light on the active control of multimode resonator systems and offers an enabling platform for the dynamic study of microcombs at microwave frequencies.

Coherent Picture on the Pure Spin Transport between Ag/Bi and Ferromagnets.

In a joint effort of both experiments and first-principles calculations, we resolve a hotly debated controversy and provide a coherent picture on the pure spin transport between Ag/Bi and ferromagnets. We demonstrate a strong inverse Rashba-Edelstein effect (IREE) at the interface in between Ag/Bi with a ferromagnetic metal (FM) but not with a ferromagnetic insulator. This is in sharp contrast to the previously claimed IREE at Ag/Bi interface or inverse spin Hall effect dominated spin transport. A more than one order of magnitude modulation of IREE signal is realized for different Ag/Bi-FM interfaces, casting strong tunability and a new direction for searching efficient spintronics materials.

The association between the vaginal microenvironment and fecundability: a register-based cohort study among Chinese women.

OBJECTIVE: To evaluate the association between the vaginal microenvironment and fecundability among women. DESIGN: Register-based nationwide cohort study. SETTING: Chinese National Free Pre-conception Check-up Project from 2015 to 2018. POPULATION: Our study included a total of 3 388 554 eligible women who were attempting to become pregnant. METHOD: We assessed the vaginal microenvironment at baseline by considering four indices: vaginal pH, clue cell examination, whiff test and vaginal cleanliness grading. If any of these indicators was abnormal, the vaginal microenvironment was defined as poor. Propensity score matching was used to control for potential confounders and reduce bias. Logistic models were used to estimate the fecundability odds ratios (FORs) after adjustment for covariates. MAIN OUTCOME MEASURES: Achievement of a pregnancy within 1 year. RESULTS: Of the total study population, 379 718 women (11.2%) had a poor vaginal microenvironment and their pregnancy rate after 1 year was significantly lower than the group with a normal microenvironment (71.8% versus 76.1%, P < 0.001). After adjusting for potential confounders, the women with a poor vaginal microenvironment were associated with a 9% reduction in fecundability compared with the normal microenvironment group (FOR 0.91, 95% CI 0.90-0.92). The adverse effects of a poor vaginal microenvironment were stronger among multipara (FOR 0.89, 95% CI 0.87-0.90) or women with irregular menstruation (FOR 0.86, 95% CI 0.84-0.89). CONCLUSION: There was a negative association between a poor vaginal microenvironment and the fecundability of women. These findings highlight the significance of assessing the vaginal microenvironment during pre-pregnancy health examinations. TWEETABLE ABSTRACT: Women with a poor vaginal microenvironment were associated with a reduction in fecundability.

[Paeoniflorin improves myocardial injury via inhibition of Src/VE-cadherin pathway in septic rats].

Objective: To study the protective effect and mechanism of paeoniflorin (pae) on myocardial injury in septic rats. Methods: Sprague-Dawley (SD) rats were randomly divided into 4 groups with 10 rats in each group. Rats were intraperitoneally injected with 1.4 ml normal saline and 1.4 ml 5% dimethyl sulfoxide (DMSO)solution independently in control group and DMSO group. Rats were intraperitoneally injected with 1.4 ml normal saline and 1.4 ml pae independently, then with 0.1 ml lipopolysaccharide (LPS) 1 hour later in sepsis group and pae group. Enzyme linked immunosorbent assay (ELISA) was used to detect serum cardiac troponin I (cTnI) levels and myocardial tissue tumor necrosis factor alpha (TNFα), interleukin(IL)-6, IL-1ß, chemokine (C-X-C motif) ligand 1 (CXCL1), chemokine (C-X-C motif) ligand 2 (CXCL2), vascular cell adhesion molecule 1 (VCAM-1) levels. Evans blue (EB) method was used to detect the EB content of myocardial tissue. HE staining method was used to observe the pathological changes, real-time quantitative polymerase chain reaction (RT-qPCR) to detect mRNA expression levels of the above molecules, and Western-blot to detect vascular endothelium-cadherin (VE-cadherin), phosphorylated p38 mitogen-activated protein kinase (P-p38MAPK), phosphorylated Src protein (P-Src), Ras-Related C3 Botulinum Toxin Substrate 1 (Rac1) levels. Results: Compared with control group, cTnI level and the EB content in sepsis group increased significantly, and the myocardial inflammatory cell infiltration was obvious. The cTnI level and EB content in pae group were significantly reduced, and myocardial inflammatory cell infiltration was reduced [cTnI: (227.7±15.9)pg/ml vs. (312.9±17.9)pg/ml;EB: (13.2±2.3)µg/g vs. (23.8±2.9)µg/g; P<0.05]. Compared with control group, the levels of TNFα, IL-6, IL-1ß, CXCL1, CXCL2, and VCAM-1 in sepsis group were increased. Compared with sepsis group, the above-mentioned molecular levels of pae group were significantly decreased [TNFα: (63.39±9.55)pg/ml vs. (126.54±19.17)pg/ml ;IL-6: (64.03±8.82)pg/ml vs. (85.60±9.52)pg/ml;IL-1ß: (69.52±9.23)pg/ml vs. (130.45±15.10)pg/ml;CXCL1: (2 600.19±379.54)pg/ml vs. (4 903.89±533.42)pg/ml;CXCL2: (93.71±10.83)pg/ml vs. (127.24±13.92)pg/ml;VCAM-1: (112.22±13.49)pg/ml vs. (149.32±15.65)pg/ml, both P<0.05]. RT-qPCR results showed that the mRNA expressions of TNFα, IL-6, IL-1ß, CXCL1, CXCL2 and VCAM-1 in the sepsis group were increased compared with the control group; Compared with sepsis group, the IL-6 mRNA (1.271±0.139 vs. 1.920±0.191, P<0.05), IL-1ßmRNA (1.180±0.130 vs. 1.817±0.191, P<0.05), VCAM-1 mRNA (1.088±0.144 vs. 1.460±0.166, P<0.05) expression decreased significantly in the pae group. Compared with control group, the levels of P-p38MAPK and P-Src in sepsis group increased, and the level of VE-cadherin decreased. Compared with sepsis group, the levels of p38MAPK and P-p38MAPK in pae group were significantly decreased, and the level of VE-cadherin was increased (p38MAPK/ß-actin: 1.125±0.078 vs. 1.520±0.164; P-p38MAPK protein: 1.639±0.133 vs. 2.112±0.222; both P<0.05). Conclusion: Paeoniflorin could improve the permeability of cardiac microvascular endothelium in sepsis rats and inhibit the secretion and expression of inflammation-related proteins and genes, which might be related to the inhibition of Src/VE-cadherin pathway by paeoniflorin.

[Studies on newly recognized chronic sialadenitis].

Some kinds of chronic sialadenitis were recognized during the recent years. They have specific pathogenesis, clinical and histopathologic appearances, and require specific treatment. IgG4-related sialadenitis (IgG4-RS) is one of the immune-mediated diseases, characterized by tumefactive lesions. The incidence of IgG4-RS obviously increased during the past 30 years. The study on the potential relationship between occupational exposure to chemical substances and the incidence of IgG4-RS showed that subjects with occupational exposure to agents known to cause IgG4-RD had an increased risk for IgG4-RS. Surgical excision of involved SMG could not control the disease progression, which is not recommended for treatment of IgG4-RS. The combination of glucocorticoid and steroid-sparing agents is effective for treating IgG4-RS, and restores salivary gland function. Radioiodine induced sialadenitis (RAIS) is one of the common complications of postoperative adjuvant treatment of differentiated thyroid cancer by 131I. The incidence of the disease is related to radiation dosage. Clinically, the patients suffered from swelling and tenderness in the buccal or submandibular regions, especially during the mealtime. Imaging appearances are similar to those of chronic obstructive sialadenitis. Conservative managements, such as gland massage, sialagogues, are the mainstream methods in the treatment of RAIS. Sialendoscopy is feasible for RAIS, but not as effective as conventional obstructive sialadenitis (COS). Therefore the prevention of RAIS is crucial. Eosinophilic sialodochitis (ES) is a new type of chronic inflammatory disease of the salivary gland related to allergy. It has characteristics of swelling of multiple major salivary glands, strip-like gelatinous plugs discharged from the duct orifice of the gland, elevated level of serum IgE and eosinophils in peripheral blood, infiltration of eosinophils and IgE positive plasma cells in the tissues, allergic history, increased expression of allergy-related cytokines, such as IL-4, IL-5, IL-13, and eotaxin, which suggest allergic reactions as a potential pathogenesis of the disease. The clinical, laboratory, histological, and immunohistochemical characteristics of ES are significantly different from conventional obstructive sialadenitis (COS). Therefore, it is suitable to separate ES from COS. Conservative managements, such as self-maintenance therapy and anti- allergic modality are the choices of treatment for ES. Based on the results of our comprehensive studies a new classification of chronic sialadenitis is suggested.

[Heritability and genetic correlation of body mass index and coronary heart disease in Chinese adult twins].

Objective: To examine the heritability of body mass index (BMI) and coronary heart disease (CHD), and to explore whether genetic factors can explain their correlation. Methods: Participants were from 11 provinces/municipalities reqistered in the Chinese National Twin Registry (CNTR) from 2010 to 2018. Participants data were collected from face-to-face questionnaire survey. Bivariate structure equation model was used to estimate the heritability and the genetic correlation of BMI and CHD. Results: A total of 20 340 pairs of same-sex twins aged ≥25 years were included in this study. After adjusting for age and gender, the heritability of BMI and CHD was 0.52 (95%CI: 0.49-0.55) and 0.76 (95%CI: 0.69-0.81), respectively. Further, a genetic correlation was identified between BMI and CHD (rA=0.10, 95%CI:0.02-0.17). Conclusion: In Chinese adult twin population, BMI and CHD are affected by genetic factors, and their correlation can be attributed to the common genetic basis.

Photonic integration of Er3+:Y2SiO5 with thin-film lithium niobate by flip chip bonding.

Rare earth ions are known as promising candidates for building quantum light-matter interface. However, tunable photonic cavity access to rare earth ions in their desired host crystal remains challenging. Here, we demonstrate the integration of erbium doped yttrium orthosilicate (Er3+:Y2SiO5) with thin-film lithium niobate photonic circuit by plasma-activated direct flip chip bonding. Resonant coupling to erbium ions is realized by on-chip electro-optically tuned high Q lithium niobate micro-ring resonators. Fluorescence and absorption of erbium ions at 1536.48 nm are measured in the waveguides, while the collective ion-cavity cooperativity with micro-ring resonators is assessed to be 0.36. This work presents a versatile scheme for future rare earth ion integrated quantum devices.

Mitigating photorefractive effect in thin-film lithium niobate microring resonators.

Thin-film lithium niobate is an attractive integrated photonics platform due to its low optical loss and favorable optical nonlinear and electro-optic properties. However, in applications such as second harmonic generation, frequency comb generation, and microwave-to-optics conversion, the device performance is strongly impeded by the photorefractive effect inherent in thin-film lithium niobate. In this paper, we show that the dielectric cladding on a lithium niobate microring resonator has a significant influence on the photorefractive effect. By removing the dielectric cladding layer, the photorefractive effect in lithium niobate ring resonators can be effectively mitigated. Our work presents a reliable approach to control the photorefractive effect on thin-film lithium niobate and will further advance the performance of integrated classical and quantum photonic devices based on thin-film lithium niobate.

Wolbachia affects reproduction in the spider mite Tetranychus truncatus (Acari: Tetranychidae) by regulating chorion protein S38-like and Rop.

Wolbachia-induced reproductive regulation in hosts has been used to control pest populations, but little is known about the molecular mechanism underlying Wolbachia regulation of host genes. Here, reproductive regulation by Wolbachia in the spider mite Tetranychus truncatus was studied at the molecular level. Infection with Wolbachia resulted in decreasing oviposition and cytoplasmic incompatibility in T. truncatus. Further RNA-seq revealed genes regulated by Wolbachia in T. truncatus. Real-time quantitative polymerase chain reaction (qPCR) showed that genes, including chorion protein S38-like and Rop were down-regulated by Wolbachia. RNA interference (RNAi) of chorion protein S38-like and Rop in Wolbachia-uninfected T. truncatus decreased oviposition, which was consistent with Wolbachia-induced oviposition decrease. Interestingly, suppressing Rop in Wolbachia-infected T. truncatus led to increased Wolbachia titres in eggs; however, this did not occur after RNAi of chorion protein S38-like. This is the first study to show that chorion protein S38-like and Rop facilitate Wolbachia-mediated changes in T. truncatus fertility. In addition, RNAi of Rop turned the body colour of Wolbachia-uninfected T. truncatus black, which indicates that the role of Rop is not limited to the reproductive regulation of T. truncatus.

The potential pigmentation-related genes in spider mites revealed by comparative transcriptomes of the red form of Tetranychus urticae.

Colouration in spider mites is due to the presence of carotenoids with diverse colours, including yellows, oranges and reds. Tetranychus urticae has two main colour forms, red and green. Although a ketolase has been implicated in determining the colour, the underlying genetic basis of body colour divergence between the two forms has remained unclear. Based on a combination of comparative transcriptomes and RNA interference, we found that a gene encoding a cytochrome P450 enzyme of the CYP4 clan (CYP389B1) had remarkably high expression in adult females of the red T. urticae, as well as in hybrids obtained by crossing the red and green forms. Down-regulation of this gene by RNA interference resulted in decreased accumulation of red pigment. Up-regulation of the expressions of a scavenger receptor gene (SCARB1) and a mitochondrial glycine transporter (SLC25A38) also strongly contributed to red colour development in adult females. Suppressing the mRNA levels of these genes also resulted in reduced accumulation of red pigment in the three other spider mites with red body colour. Our results provide evidence that the body colour divergence between the two forms is caused by different expressions of pigmentation-related genes, and point to a possible role of a novel cytochrome P450 gene (CYP389B1) in regulating red-orange body colour. These findings expand the number of candidate cytochrome P450 genes involved in endogenous pigmentation and will help to understand their roles in determining colour patterns in mites and other species.

Stable tuning of photorefractive microcavities using an auxiliary laser.

Cavity nonlinear optics enables intriguing physical phenomena to occur at micro- or nano-scales with modest input powers. While this enhances capabilities in applications such as comb generation, frequency conversion, and quantum optics, undesired nonlinear effects including photorefraction and thermal bistability are exacerbated. In this Letter, we propose and demonstrate a highly effective method of achieving cavity stabilization using an auxiliary laser for controlling photorefraction in a z-cut periodically poled lithium niobate (LN) microcavity system. Our numerical study accurately models the photorefractive effect under high input powers, guiding future analyses and development of LN microcavity systems.

Photorefraction-induced Bragg scattering in cryogenic lithium niobate ring resonators.

We report intracavity Bragg scattering induced by the photorefractive (PR) effect in high-Q lithium niobate ring resonators at cryogenic temperatures. We show that when a cavity mode is strongly excited, the PR effect imprints a long-lived periodic space-charge field. This residual field in turn creates a refractive index modulation pattern that dramatically enhances the back scattering of an incoming probe light, and results in selective and reconfigurable mode splittings. This PR-induced Bragg scattering effect, despite being undesired for many applications, could be utilized to enable optically programmable photonic components.