Photochemical Reaction Enabling the Engineering of Photonic Spin-Orbit Coupling in Organic-Crystal Optical Microcavities.

The control and active manipulation of spin-orbit coupling (SOC) in photonic systems are fundamental in the development of modern spin optics and topological photonic devices. Here, we demonstrate the control of an artificial Rashba-Dresselhaus (RD) SOC mediated by photochemical reactions in a microcavity filled with an organic single crystal of photochromic phase-change character. Splitting of the circular polarization components of the optical modes induced by photonic RD SOC is observed experimentally in momentum space. By applying an ultraviolet light beam, we control the spatial molecular orientation through a photochemical reaction, and with that we control the energies of the photonic modes. This way, we realize a reversible conversion of spin splitting of the optical modes with different energies, leading to an optically controlled switching between circularly and linearly polarized optical modes in our device. Our strategy of in situ and reversible engineering of SOC induced by a light field provides a promising approach to actively design and manipulate synthetic gauge fields toward future on-chip integration in photonics and topological photonic devices.

Tunable Triplet-Mediated Multicolor Lasing from Nondoped Organic TADF Microcrystals.

Thermally activated delayed fluorescent (TADF) emitters have received great attention in organic light-emitting diodes and laser diodes because of high exciton utilization efficiency and low optical loss caused by triplets. However, the direct observation of lasing emission from nondoped TADF microcrystals has yet to be reported. Here, we demonstrated a three-color (green, yellow, and red) microlaser from three nondoped TADF microcrystals with well-controlled geometries. The temperature-dependent dynamic analyses testify that the regenerated singlets which originated from the reverse intersystem crossing process at room temperature are beneficial for population inversion and reduce triplet-absorption/annihilation optical loses, together resulting in thermally activated lasing actions. Thanks to single-crystalline structures of TADF emitters, the relationship between triplet-harvesting capability and the molecular structure was systematically investigated. The results not only offer rational design of pure TADF gain materials but also provide guidance for the high-performance electrically driven organic solid-state lasers and multicolor laser integration.

Double signal enhancement strategy based on rolling circle amplification and photoinduced electron transfer for ultrasensitive fluorometric detection of methylated DNA.

The authors describe a novel assay for the detection of methylated DNA site. Rolling circle amplification and CdSe/ZnS quantum dots with high fluorescence efficiency are applied in this method. The CdSe/ZnS quantum dots act as electron donors, and hemin and oxygen (derived from hydrogen peroxide act as acceptors in photoinduced electron transfer. The assay, best performed at excitation/emission peaks of 450/620 nm, is sensitive and specific. Fluorometric response is linear in the 1 pM to 100 nM DNA concentration range, and the lowest detectable concentration of methylated DNA is 142 fM (S/N = 3). The method is capable of recognizing 0.01% methylated DNA in a mixture of methylated/unmethylated DNA. Graphical abstract A novel method for methylated sites detection in DNA is established. Rolling circle amplification and photoinduced electron transfer. CdSe/ZnS quantum dots with high fluorescence efficiency act as the electron donor, while G-quadruplex/hemin and hydrogen peroxide derived oxygen act as electron acceptor. It presents a linear response towards 1 pM to 100 nM methylated DNA with a correlation coefficient of 0.9968, and the lowest detectable concentration of methylated DNA was 142 fM, with selectivity significantly superior to other methods.

Tunable Heck-Mizoroki Reaction of Dibromonaphthalene Diimide with Aryl Ethylenes: Design, Synthesis, and Characterization of Coplanar NDI-Based Conjugated Molecules.

Rational design of coplanar NDI-based conjugated molecules was achieved by covalently connecting naphthalene diimide (NDI) units with aryl (Ar) groups through vinylene (V) linkers via Heck-Mizoroki reaction. Two series of products, diolefination products (ArVNDIVAr) and hydroxylated and mono-olefination products (HONDIVAr), can be obtained, respectively, in moderate to excellent yields (45-90%) under controlled conditions, in which catalyst and base play the key roles. Density functional theory calculation discloses the outstanding planarity of the two types of products. Large bathochromic shifts are observed in both the absorbance and photoluminescence spectra of the HONDIVAr (144 and 229 nm) and ArVNDIVAr (180 and 242 nm) π-systems. Bathochromic shifts can be adjusted within the broad wavelength range by introducing 4'-substituents, either electron-withdrawing group (NO2) or electron-donating group (NMe2), in the phenyl group of aryl ethylenes. ArVNDIVArs show bigger bathochromic shifts than HONDIVArs.

[Effect of electroacupuncture on pain threshold and expression of pain-related factors cyclooxygenase-2, prostaglandin E2 and ß-endorphin in rats with chronic pelvic pain syndrome].

OBJECTIVE: To explore the possible mechanism of electroacupuncture (EA) underlying improvement of chronic pelvic pain syndrome (CPPS). METHODS: Fifty SD rats were randomly divided into control, model, sham operation, EA and sham EA groups (n=10 rats in each group). The CPPS model was established by injecting complete Freund's adjuvant (CFA, 50 µL) into the ventral lobes of the prostate. EA (2 Hz/100 Hz) was applied to "Guanyuan"(CV4), "Zhongji"(CV3), "Sanyinjiao" (SP6) and "Huiyang"(BL35) once daily for 40 min, 5 days a week for 4 weeks, while rats in the sham EA group were treated with the same acupoints but without electrical stimulation. Mechanical pain threshold (MPT) and heat pain threshold (HPT) were measured before and after intervention. The body weight and prostate weight were measured and prostate index was calculated. Histopathological changes of prostate tissue were observed by HE staining. The levels of cycloxygenase-2 (COX-2), prostaglandin E2 (PGE2) and ß-endorphin (ß-EP) in prostate tissue were detected by ELISA. RESULTS: Compared with the control and sham operation groups, the MPT and HPT were significantly lower (P<0.01), and the prostate weight, prostate index, the contents of PGE2 and COX-2 were significantly increased (P<0.01), while the content of ß-EP was significantly decreased (P<0.01) in the model group. Compared with the model group, the MPT and HPT were significantly increased (P<0.01) after 3 and 4 courses of treatment, and the prostate weight, prostate index, the contents of PGE2 and COX-2 were significantly decreased (P<0.01), while the content of ß-EP was significantly increased (P<0.01) in the EA group, rather than in the sham EA group (P>0.05). CONCLUSION: EA can effectively relieve pain in CPPS rats, which may be related to its functions in down-regulating COX-2 and PGE2, and up-regulating ß-EP.

Electrically Switchable Amplified Spontaneous Emission from Lead Halide Perovskite Film.

Electrically tunable optical devices that allow for modulation and detection of the optical signals would be extremely beneficial for the next photonic and electronic technologies. Perovskite materials as an emerging excitonic one provide promising platforms because they offer excitons manipulated by an external electrical field and efficient coupling to light. However, so far, electrically modulated switches based on perovskite amplified spontaneous emission (ASE) still remain unexplored. Here, we prepared perovskite films on indium tin oxide substrates by a spin-coating method and characterized their ASE behaviors. Based on it, we designed and fabricated electrically switchable ASE devices of perovskite film based on a light-emitting diode device configuration. Under the externally applied current, this device exhibits good controllable optoelectronic switching behaviors. Furthermore, this photoelectric response can be modulated by the different current densities. Our strategy for electrically switchable perovskite ASE will promote integrated applications in optoelectronic devices and provide valuable experience for the development of electrically pumped perovskite lasers.

Efficacy on rabbits with arrhythmia: needling acupoint of Neiguan (PC6) at shallow or deep depth, and retaining needles for 10, 20, or 30 min.

OBJECTIVE: To compare the effects of Neiguan (PC6) acupuncture at different depths and retention time on arrhythmia duration, myocardial tissue morphology, mRNA expression level of L-type calcium channel α1C subunit and Ca2 + -Mg2 + -AtPase activity in tachirrhythmia model of rabbits. METHODS: The tachyarrhythmia model was made by intravenous injection of barium chloride into the ears of rabbits. A total of 56 healthy adult male New Zealand big-eared white rabbits, apply the random number table method, divided into normal control group (group A), model group (group B), shallow needling Neiguan (PC6) 10 min group (group C), shallow needling Neiguan (PC6) 20 min group (group D), shallow needling Neiguan (PC6) 30 min group (group E), deep needling Neiguan (PC6) 10 min group (group F), deep needling Neiguan (PC6) 20 min group (group G), deep needling Neiguan (PC6) 30 min group (group H), 7 animals in each group. Electrocardiograms were used to collect the duration of arrhythmia; hematoxylin-eosin staining method was performed on myocardial tissue, RT-PCR tested the expression of α1C subunit mRNA, and the activity of Ca2 + -Mg2 + -ATPase were quantified by phosphorus determination method. RESULTS: The duration of arrhythmia in each acupuncture treatment group was shortened to varying degrees. Compare to the model group, the tissue damage from barium chloride inducing was improved in the acupuncture group. Compared to the model group, except for group E, most treatment groups had varying degrees of improvement with significantly down-regulated L-type calcium channel α1C subunit mRNA expressions level and increased Ca2+ -Mg2+ -ATPase activity. CONCLUSIONS: The effect of acupuncture at Neiguan (PC6) with different depths and retention time can reduce the duration of arrhythmia induced by barium chloride relatively, improve the induced pathological changes, down regulate L-type calcium channel α1C subunit mRNA expressions level and increase Ca2 + -Mg2 + -ATPase activity. Both the shallow and deep tissues of Neiguan (PC6) may be involved in transmitting acupuncture information. There is an optimal induction period for shallow needling at Neiguan (PC6) to reach the best therapeutic effect.

[Effect of acupuncture at different layers of local "Neiguan" (PC6) tissue on arrhythmia and expression of myocardial Cx43 in rabbits].

OBJECTIVE: To compare the therapeutic effect of shallow and deep needling at "Neiguan"(PC6) in the treatment of arrhythmia in rabbits. METHODS: Male New Zealand rabbits were randomly divided into saline (n＝15), model (n＝12), shallow needling (n＝13) and deep needling (n＝12) groups. The arrhythmia model was established by ear intravenous injection of Barium chloride (0.4%, 1 mL/kg). Acupuncture needle was inserted into the superficial fascia (about 3 mm beneath the skin) or deep layer (5 to 8 mm, near the median nerve) of local PC6 tissue (fore limb), manipulated for a while and then retained for 10 min. Histopathological changes of myocardium was observed after H．E. stain, and the immunoactivity of connexin 43 (Cx43) detected by immunohistochemistry(IHC). RESULTS: Various degrees of arrhythmia and down-regulated expression of myocardial Cx43 were observed in all rabbits after modeling. After EA intervention and compared with the model group, the initial time of arrhythmia and Cx43 expression were obviously increased (P<0.01), and the duration of arrhythmia was significantly shortened in both deep and shallow needling groups (P<0.01). Compared with the shallow needling group, the Cx43 expression was increased in the deep needling group (P<0.01). H．E. staining showed disordered and wavy arrangement of myocardial fibers, with exudation of serous and erythrocytes in the myocardial interstitium in the model group, which was relatively mild in both needling groups. IHC showed disordered distribution of Cx43 in the ventricular myocytes and almost no obvious band-like distribution at the discs in rabbits of the model group, and abundant distribution of Cx43 in the sacral disc in the deep needling group, and strip-shaped, cluster-like, point-like, visible at both end-to-end connections and side-to-side connections in the shallow needling group. CONCLUSION: Both shallow and deep needling can significantly reduce the duration of arrhythmia in arrhythmia rabbits, which may be associated with its effect in up-regulating expression of myocardial Cx43 protein.

[Microcirculation changes of three yin-meridians of hand in the forearm in rabbits with arrhythmia: a comparative study].

OBJECTIVE: To observe the microcirculation changes of three yin-meridians of hand in the forearm in rabbits with arrhythmia, and to compare the differences of responses among the three yin-meridians of hand. METHODS: A total of 20 New Zealand rabbits were randomly divided into a saline group and a model group, 10 rabbits in each one. The rabbits were anesthetized with intravenous injection of 20% ethyl carbamate (3.3 mL/kg) at ear vein; the saline group was injected with 0.9% sodium chloride solution (1 mL/kg), while the model group was injected with 0.4% barium chloride solution (1 mL/kg) to establish the arrhythmia model. The microcirculation changes of the three yin-meridians of hand were observed and analyzed by laser speckle blood flow imaging technique before and after the intervention. RESULTS: Compared before modeling, the microcirculation perfusion of the three yin-meridians of hand in the model group was significantly reduced (P<0.01), and the reduction in the jueyin meridian was more significant than that in the shaoyin meridian (P<0.05), but there was no significant difference between the taiyin meridian and shaoyin meridian (P>0.05). There was a negative correlation between microcirculation perfusion and position (P<0.001), indicating the closer to the elbow, the more the microcirculation perfusion decreased. CONCLUSION: During arrhythmia in rabbits, the dysfunction of qi and blood existes in the three yin-meridians of hand in the forearm, particularly the jueyin meridian. In addition, the closer to the elbow, the more obvious the reaction of the three yin-meridians of hand is.

Tunable and highly regio- and diastereoselective vinylogous Mannich-type reaction of dioxinone-derived silyl dienolate.

A tunable and highly regio- and diastereoselective vinylogous Mannich-type reaction of dioxinone-derived silyl dienolate (1) with chiral N-tert-butanesulfinyl imino ester (2) was developed. By appropriate choice of Lewis acid catalyst, two diastereomers of the gamma-product were obtained, respectively, with dr up to 95:5. The procedure for the Ag(I)-catalyzed vinylogous Mannich-type reaction also provided facile access to the alpha-regioisomer with excellent diastereoselectivities (up to >99:1 dr) by changing the counterion of the Ag(I) salt.

FeCl3-Mediated Radical Tandem Reactions of 3-Benzyl-2-oxindoles with Styrene Derivatives for the Stereoselective Synthesis of Spirocyclohexene Oxindoles.

A novel FeCl3-mediated reaction of 3-benzyl-2-oxindoles with styrene derivatives was developed. The reaction provided spirocyclohexene oxindoles in good yields and excellent diastereoselectivities via a tandem radical addition/cyclization process.

Highly enantioselective [3 + 2]-annulation of isatin-derived morita-baylis-hillman adducts with cyclic sulfonimines.

An organocatalytic [3 + 2]-annulation between isatin-derived Morita-Baylis-Hillman adducts and cyclic sulfonimines has been developed in high yields with excellent enantio- and diastereoselectivities via an allylic nitrogen-ylide intermediate. The reaction provides access to heavily substituted aza-spirooxindole derivatives, which also contain ring fused cyclic sultams.