Generation of High-Density High-Polarization Positrons via Single-Shot Strong Laser-Foil Interaction.

We put forward a novel method for producing ultrarelativistic high-density high-polarization positrons through a single-shot interaction of a strong laser with a tilted solid foil. In our method, the driving laser ionizes the target, and the emitted electrons are accelerated and subsequently generate abundant γ photons via the nonlinear Compton scattering, dominated by the laser. These γ photons then generate polarized positrons via the nonlinear Breit-Wheeler process, dominated by a strong self-generated quasistatic magnetic field B^{S}. We find that placing the foil at an appropriate angle can result in a directional orientation of B^{S}, thereby polarizing positrons. Manipulating the laser polarization direction can control the angle between the γ photon polarization and B^{S}, significantly enhancing the positron polarization degree. Our spin-resolved quantum electrodynamics particle-in-cell simulations demonstrate that employing a laser with a peak intensity of about 10^{23} W/cm^{2} can obtain dense (≳10^{18} cm^{-3}) polarized positrons with an average polarization degree of about 70% and a yield of above 0.1 nC per shot. Moreover, our method is feasible using currently available or upcoming laser facilities and robust with respect to the laser and target parameters. Such high-density high-polarization positrons hold great significance in laboratory astrophysics, high-energy physics, and new physics beyond the standard model.

Manipulation of Giant Multipole Resonances via Vortex γ Photons.

Traditional photonuclear reactions primarily excite giant dipole resonances, making the measurement of isovector giant resonances with higher multipolarities a great challenge. In this Letter, the manipulation of collective excitations of different multipole transitions in even-even nuclei via vortex γ photons is investigated. We develop the calculation method for photonuclear cross sections induced by the vortex γ photon beam using the fully self-consistent random-phase approximation plus particle-vibration coupling (RPA+PVC) model based on Skyrme density functional. We find that the electromagnetic transitions with multipolarity J<|m_{γ}| are forbidden for vortex γ photons due to the angular momentum conservation, with m_{γ} being the projection of total angular momentum of γ photon on its propagation direction. For instance, this allows for probing the isovector giant quadrupole resonance without interference from dipole transitions using vortex γ photons with m_{γ}=2. Furthermore, the electromagnetic transition with J=|m_{γ}|+1 vanishes at a specific polar angle. Therefore, the giant resonances with specific multipolarity can be extracted via vortex γ photons. Moreover, the vortex properties of γ photons can be meticulously diagnosed by measuring the nuclear photon-absorption cross section. Our method opens new avenues for photonuclear excitations, generation of coherent γ photon laser and precise detection of vortex particles, and consequently, has significant impact on nuclear physics, nuclear astrophysics and strong laser physics.

Salvianolic acid B ameliorates retinal deficits in an early-stage Alzheimer's disease mouse model through downregulating BACE1 and Aß generation.

Alzheimer's disease (AD) is a neurodegenerative disease with subtle onset, early diagnosis remains challenging. Accumulating evidence suggests that the emergence of retinal damage in AD precedes cognitive impairment, and may serve as a critical indicator for early diagnosis and disease progression. Salvianolic acid B (Sal B), a bioactive compound isolated from the traditional Chinese medicinal herb Salvia miltiorrhiza, has been shown promise in treating neurodegenerative diseases, such as AD and Parkinson's disease. In this study we investigated the therapeutic effects of Sal B on retinopathy in early-stage AD. One-month-old transgenic mice carrying five familial AD mutations (5×FAD) were treated with Sal B (20 mg·kg-1·d-1, i.g.) for 3 months. At the end of treatment, retinal function and structure were assessed, cognitive function was evaluated in Morris water maze test. We showed that 4-month-old 5×FAD mice displayed distinct structural and functional deficits in the retinas, which were significantly ameliorated by Sal B treatment. In contrast, untreated, 4-month-old 5×FAD mice did not exhibit cognitive impairment compared to wild-type mice. In SH-SY5Y-APP751 cells, we demonstrated that Sal B (10 µM) significantly decreased BACE1 expression and sorting into the Golgi apparatus, thereby reducing Aß generation by inhibiting the ß-cleavage of APP. Moreover, we found that Sal B effectively attenuated microglial activation and the associated inflammatory cytokine release induced by Aß plaque deposition in the retinas of 5×FAD mice. Taken together, our results demonstrate that functional impairments in the retina occur before cognitive decline, suggesting that the retina is a valuable reference for early diagnosis of AD. Sal B ameliorates retinal deficits by regulating APP processing and Aß generation in early AD, which is a potential therapeutic intervention for early AD treatment.

Brilliant circularly polarized γ-ray sources via single-shot laser plasma interaction.

Circularly polarized (CP) γ-ray sources are versatile for broad applications in nuclear physics, high-energy physics, and astrophysics. The laser-plasma based particle accelerators provide accessibility for much higher flux γ-ray sources than conventional approaches, in which, however, the circular polarization properties of the emitted γ-photons are usually neglected. In this Letter, we show that brilliant CP γ-ray beams can be generated via the combination of laser plasma wakefield acceleration and plasma mirror techniques. In a weakly nonlinear Compton scattering scheme with moderate laser intensities, the helicity of the driving laser can be transferred to the emitted γ-photons, and their average polarization degree can reach ∼61% (20%) with a peak brilliance of ≳1021 photons/(s · mm2 · mrad2 · 0.1% BW) around 1 MeV (100 MeV). Moreover, our proposed method is easily feasible and robust with respect to the laser and plasma parameters.

One new and seven known triterpene glycosides from the aerial parts of Cimicifuga dahurica.

One new triterpene glycoside, asiaticoside I (1), along with seven known ones (2-8), were isolated from the aerial parts of Cimicifuga dahurica (Turcz.) Maxim. The structure of 1 was elucidated on the basis of extensive spectroscopic methods including 1D-NMR, 2D-NMR and MS data. The structures of known compounds were determined by comparison with the literature data. Compound 1 exhibited moderate cell growth inhibitory activities in vitro against HELF, non-small cell lung cancer A549, and pancreatic cancer PANC-1 cell lines, with IC50 values of 62.97, 43.19, and 60.40 µM, respectively.

Unique phenolic constituent in Cimicifuga dahurica (Turcz.) Maxim. through Box-Behnken design and response surface methodology.

Cimicifuga dahurica (Turcz.) Maxim. exerts significant antioxidative due to its high phenolic constituent content. In this study, the extraction condition of the phenolic constituents and antioxidant effect was optimized by the Box-Behnken design and response surface methodology. Eleven main bioactive analytes of Cimicifuga dahurica (Turcz.) Maxim. were simultaneously quantified by high-performance capillary electrophoresis with diode-array detector to assess the effect of extraction technology. The optimal extraction parameters were determined as: the concentration of ethanol 56.21%, liquid/solid ratio 14.65:1, and extraction time 1.64 h for 2.67 times. According to the results, a maximal value of total phenolic acids (3.67 mg/g) was obtained. Meanwhile, the influence of different extraction technology on antioxidant activities were evaluated by 1,1-diphenyl-2-picrylhydrazyl, 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonate), ferric reducing antioxidant power and hydroxyl radical scavenging method. The results presented here showed that the content of phenolic acid and antioxidant effect was much higher than the European Pharmacopoeia. Altogether, this method successfully applied response surface methodology to optimize the Cimicifuga dahurica (Turcz.) Maxim. extract with high antioxidant activities.

Two new phenolic acids from the fruits of Forsythia suspense.

Two new phenolic acids forsythiayanoside C (1) and forsythiayanoside D (2), were isolated from the fruits of Forsythia suspense (Thunb.) Vahl. Their structures were elucidated on the basis of chemical and spectral analysis, including 1D, 2D NMR analyses, HRESIMS and CD spectrometry. The cytotoxic and antioxidant activities testing showed that compound 2 exhibited free radical scavenging activity.

Chemical constituents from rhizome of Anemone amurensis.

Phytochemical investigation of the 70% EtOH extract of the rhizome of Anemone amurensis led to the isolation of two new oleanane-type triterpenoid saponins 1 and 2. Their structures were elucidated on the basis of chemical and spectral analysis, including 1D, 2D NMR data, and HR-ESI-MS. Compounds 1 and 2 were tested for cytotoxicities against two human cancer cell lines (A549 and Hep-G2). Compound 2 showed potent cytotoxicity with IC50 values of 38.53 and 66.17 µM, respectively, while compound 1 with IC50 > 100 µM.

Two new triterpenoid saponins from rhizome of Anemone amurensis.

Two new triterpenoid saponins were isolated from the 70% ethanol extract of the rhizome of Anemone amurensis, they are oleanolic acid 28-O-ß-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranosyl-(1 → 4)-ß-d-glucopyranosyl-(1 → 6)-ß-d-glucopyranosyl ester (1) and 23,27-dihydroxy oleanolic acid 3-O-α-l-arabinopyranoside (2). The structures of 1 and 2 were elucidated on the basis of chemical and spectral analysis, including 1D and 2D NMR data and HR-ESI-MS. Compounds 1 and 2 were tested for cytotoxicities against three human cancer cell lines (A549, Hep-G2, and MCF-7). Compound 1 showed potent cytotoxicity with IC50 values of 34.76, 41.17, and 28.92 µM, respectively, while compound 2 with IC50>100 µM.

Recovering from prolonged cardiac arrest induced by electric shock: A case report.

BACKGROUND: Cardiac arrest (CA) induced by electric shock is a rare occurrence, particularly in cases of prolonged CA. Currently, there is limited literature on similar incidents, and we present a relevant case report. CASE SUMMARY: A 27-year-old Asian male man, experiencing respiratory CA due to electric shock, was successfully restored to sinus rhythm after 50 min of cardiopulmonary resuscitation and 8 electrical defibrillation sessions. In the subsequent stages, the patient received multiple organ function protection measures, leading to a successful recovery and eventual discharge from the hospital. CONCLUSION: Prolonging resuscitation time can enhance the chances of survival for patients, this study provide valuable insights into the management of electric shock-induced CA.

Three new phenols and one new lignan from Clematis terniflora var. manshurica (Rupr.) Ohwi with their anti-inflammatory activity.

Three undescribed phenols, mandshusica C-E (1-3) and a new lignan, mandshusica F (5), along with six known compounds (4, 6-10) were isolated from the roots and rhizomes of Clematis terniflora var. manshurica (Rupr.) Ohwi. Their structures were elucidated by extensive spectroscopic analysis as well as NMR and ECD calculations. Moreover, the possible biosynthetic pathways of compounds 1-3 were also discussed. All compounds were evaluated for their anti-inflammatory activities in LPS-induced RAW 264.7 cells. Compounds 1, 3, 4 significantly reduced the levels of NO and TNF-α, while compounds 2 and 8 significantly inhibited NO production in LPS-induced RAW264.7 cells.

A new cycloartane nortriterpenoid from stem and leaf of Quercus variabilis.

A new compound 3-acetyloxy-epicycloeucalenol-24-one (1), with 11 known compounds 3α-acetyloxy-4α,14α-dimethyl-9ß,19-cycloergost-24-oic acid (2), 3-epicycloeucalenol (3), 3-epicycloeucalenyl-24-one (4), 3-epicycloeucalenyl acetate (5), 4ß,14α-dimethyl-5α-ergosta-9ß,19-cyclo-24(31)-en-3ß-hydroxy-4α-carboxylic acid (6), cycloeucalenone (7), friedelin (8), epifriedelanol (9), lup-20 (29)-en-3ß,30-diol (10), betulin (11), lupeol (12), was isolated from the stems and leaves of Quercus variabilis Blume. Seven compounds (1-7) showed anti-inflammatory activity.

Two new anti-inflammatory compounds from the roots and rhizomes of Clematis terniflora var. manshurica (Rupr.) Ohwi.

Two new compounds named mandshurica A (1) and mandshurica B (2), together with four known lignans (3-6) were isolated from the roots and rhizomes of Clematis terniflora var. manshurica (Rupr.) Ohwi. The structures of the new compounds were elucidated by HR-ESI-MS, 1D and 2D NMR spectroscopy. Moreover, the anti-inflammatory activity of compounds 1 and 2 were evaluated against lipopolysaccharide-induced mouse macrophage RAW264.7 cells. Compounds 1 and 2 displayed significant inhibitory effect on NO production, and compound 2 exhibited obvious inhibition on the pro-inflammatory cytokines TNF-α. Both new compounds showed potential anti-inflammatory activity.

Direct calibration of neutron detectors for laser-driven nuclear reaction experiments with a gated neutron source.

Nowadays, the sustained technological progress in high-intensity lasers is opening up the possibility of super-intense laser pulses to trigger or substantially influence nuclear reactions. However, it is a big challenge to quantitatively measure the reaction products because of the interference of electromagnetic pulses induced by high-intensity lasers. Fast scintillation detectors are widely chosen for fast neutron detection. The calibration of neutron detectors is crucial to measuring the yield of neutron products. Since one large signal superimposed by a number of neutron signals appears during a short period, it is difficult to directly and precisely calibrate the detectors' response for a single neutron. In the present work, we developed a direct calibration method with a gated fission neutron source 252Cf to solve this problem. This work demonstrates that the gated fission neutron source approach, with a unique "Pulse Shape Discrimination & Time of Flight window" function, has the highest background-γ-rejection and improves the confidence level of the final results for both liquid and plastic scintillator. Compared with the result of Compton edge method and neutron beam method, the gated fission neutron source method achieves much cleaner neutron signals and avoids interference caused by the modeling accuracy of the neutron detectors. This approach can be widely used in laser-driven nuclear physics experiments with higher accuracy for neutron detection.

Amelioration of olfactory dysfunction in a mouse model of Parkinson's disease via enhancing GABAergic signaling.

BACKGROUND: Olfactory dysfunction is among the earliest non-motor symptoms of Parkinson's disease (PD). As the foremost pathological hallmark, α-synuclein initiates the pathology in the olfactory pathway at the early stage of PD, particularly in the olfactory epithelium (OE) and olfactory bulb (OB). However, the local neural microcircuit mechanisms underlying olfactory dysfunction between OE and OB in early PD remain unknown. RESULTS: We observed that odor detection and discrimination were impaired in 6-month-old SNCA-A53T mice, while their motor ability remained unaffected. It was confirmed that α-synuclein increased and accumulated in OB but not in OE. Notably, the hyperactivity of mitral/tufted cells and the excitation/inhibition imbalance in OB were found in 6-month-old SNCA-A53T mice, which was attributed to the impaired GABAergic transmission and aberrant expression of GABA transporter 1 and vesicular GABA transporter in OB. We further showed that tiagabine, a potent and selective GABA reuptake inhibitor, could reverse the impaired olfactory function and GABAergic signaling in OB of SNCA-A53T mice. CONCLUSIONS: Taken together, our findings demonstrate potential synaptic mechanisms of local neural microcircuit underlying olfactory dysfunction at the early stage of PD. These results highlight the critical role of aberrant GABAergic signaling of OB in early diagnosis and provide a potential therapeutic strategy for early-stage PD.

A novel selected force controlling method for improving robotic grinding accuracy of complex curved blade.

Nonlinear time-varying contact state is a crucial factor to prevent the traditional robotic belt grinding method from precision machining of blade. In this case, a novel selected force controlling method (SFC) with consideration of regional division (RD) based on machining allowance is proposed for improving robotic grinding accuracy of complex curved blade, on basis of the self-developed adaptive impedance controller. Ideal normal grinding force at each cutter-contact (CC) point is calculated by principal curvature radius and regional allowance of blade surface. Then, the CC points with similar ideal normal grinding force are divided into one region along grinding path based on the force threshold. Furthermore, an adaptive impedance controller with neural network online compensation algorithm (AICNN) is developed, and the verification test results of grinding four profile areas of intake side, exhaust side, convex and concave, indicate that the force control accuracy with AICNN has increased by 80.33%, 50.58%, 82.65% and 69.01% than that without the controller, respectively. Based on this, the grinding experiment of typical turbine blade is conducted with SFC, and the surface profile accuracy values at the four profile areas have evidently improved by 48.79%, 35.67%, 59.54%, and 66.90% than that with conventional grinding (CG), respectively.

Isolation and structural elucidation of a low-molecular-weight polysaccharide from the roots of Panax ginseng C. A. Meyer.

A low-molecular-weight polysaccharide named MCGP-L was extracted and purified from the roots of Mountain cultivated ginseng (Panax ginseng C. A. Meyer). The polysaccharide MCGP-L was purified by molecular exclusion chromatography using the Sephadex G-25 column. The average molecular weight of MCGP-L was estimated to be 3 × 103 kDa. Monosaccharide composition analysis showed MCGP-L was composed of three kinds of monosaccharide: D-glucose, D-galactose and D-mannose. The physicochemical properties and structural characteristics of MCGP-L were investigated by the combination of chemical and instrumental analysis such as methylation analysis, High Performance Gel-Permeation Chromatography (HPGPC), High Performance Liquid Chromatography (HPLC) and Nuclear Magnetic Resonance (NMR). The backbone of MCGP-L was composed of (1→4)-linked-α-D-Glcp residues and with branch chain substituted at O-6 position of (1→4,6)-linked-α-D-Glcp. The branch chain consists of →6)-α-D-Galp-(1→, →2)-α-D-Manp-(1→ and ß-D-Glcp-(1→.

New anti-pulmonary fibrosis prenylflavonoid glycosides from Epimedium koreanum.

Four new prenylflavonoid glycosides, namely koreanoside H-K (1-4), together with eleven known ones (5-15) were isolated from the leaves of Epimedium koreanum Nakai. Their structures were elucidated by 1D NMR, 2D NMR, HR-ESI-MS, IR and UV. The identification of the sugar moieties was carried out by means of acid hydrolysis and HPLC analysis of their derivatives. It is worth noting that compound 3 and compound 4 were elucidated to contain fucose and quinovose moieties, which were two extremely rare sugar units from the genus Epimedium. The anti-pulmonary fibrosis activity of the new compounds was evaluated using A549 cell line. Compounds 1, 2 and 4 showed significant anti-pulmonary fibrosis activities.

Dual-responsive polyacrylonitrile-based electrospun membrane for controllable oil-water separation.

Membrane separation based on smart materials with responsive wettability has attracted great attention due to the excellent performance of controllable oil-water separation. Herein, responsive copolymer originated from N-isopropylacrylamide and 2-(dimethylamino) ethyl methacrylate was synthesized and electrospun with polyacrylonitrile to fabricate smart composite membrane. The introduction of the responsive copolymer endowed the membrane with stimuli-responsive wettability to pH and temperature. Specifically, at the initial state, water was selectively blocked while oil passed through the membrane. After treatment with acidic water or CO2, the reverse separation was realized due to the protonation of the tertiary amine group in the copolymer. Water was selectively passed through the membrane after heat treatment because of the structural change of membrane upon temperature. The developed membrane was able to separate different types of oil-water mixtures and surfactant-stabled emulsions with high efficiency. Additionally, two membranes controlled by temperature and pH were designed to construct a logic AND gate for oil-water separation, and the results demonstrated that only the temperature and acidity of the solution were simultaneously satisfied, the water could flow through the valve combination, and such capability made this smart membrane great potential for remotely controlling the oil-water separation process.

A new triterpenoid saponin with nine sugar units from Anemone amurensis (Korsh.) Kom.

A new triterpenoid saponin named Anemonside A (1) was isolated from the rhizome of Anemone amurensis (Korsh.) Kom. Its structure was determined by chemical and spectral analysis, including 1D, 2D NMR data, HRESIMS and hydrolysis reaction. The new saponin contains nine sugar units with two O-linked sugar chains, which is relatively rare in natural products. In addition, the cytotoxic activity of Anemonside A was evaluated by against A549 and HepG2 cell lines with the MTT method and showed no cytotoxic activity with IC50 over 100 µM.