Enantioselective copper-catalyzed azidation/click cascade reaction for access to chiral 1,2,3-triazoles.

Chiral 1,2,3-triazoles are highly attractive motifs in various fields. However, achieving catalytic asymmetric click reactions of azides and alkynes for chiral triazole synthesis remains a significant challenge, mainly due to the limited catalytic systems and substrate scope. Herein, we report an enantioselective azidation/click cascade reaction of N-propargyl-ß-ketoamides with a readily available and potent azido transfer reagent via copper catalysis, which affords a variety of chiral 1,2,3-triazoles with up to 99% yield and 95% ee under mild conditions. Notably, chiral 1,5-disubstituted triazoles that have not been accessed by previous asymmetric click reactions are also prepared with good functional group tolerance.

Unraveling the toxicity response and metabolic compensation mechanism of tannic acid-Cr(III) complex on alga Raphidocelis subcapitata.

Due to their assembly properties and variable molecular weights, the potential biological toxicity effects of macromolecular organic ligand heavy metal complexes are more difficult to predict and their mechanisms are more complex. This study unraveled the toxicity response and metabolic compensation mechanism of tannic acid-Cr(III) (TA-Cr(III)) complex on alga Raphidocelis subcapitata using multi-omics approaches. Results showed TA-Cr(III) complex caused oxidative damage and photosystem disruption, destroying the cell morphology and inhibiting algal growth by >80 % at high exposure levels. TA-Cr(III) complex stress down-regulated proteins linked to proliferation, photosynthesis and antioxidation while upregulating carbon fixation, TCA cycle and amino acid metabolism. The increase of fumarate, citrate, isocitrate and semialdehyde succinate was validated by metabolomics analysis, which improved the TCA cycle, amino acid metabolism and carbon fixation. Activation of the above cellular processes somewhat compensated for the inhibition of algal photosynthesis by TA-Cr(III) complex exposure. In conclusion, physiological toxicity coupled with downstream metabolic compensation in response to Cr(III) complex of macromolecular was characterized in Raphidocelis subcapitata, unveiling the adaptive mechanism of algae under the stress of heavy metal complexes with macromolecular organic ligands.

Controlling magnon-magnon entanglement and steering by atomic coherence.

Here we show that it is possible to control magnon-magnon entanglement in a hybrid magnon-atom-cavity system based on atomic coherence. In a four-level V-type atomic system, two strong fields are applied to drive two dipole-allowed transitions and two microwave cavity modes are coupled with two dipole forbidden transitions as well as two magnon modes simultaneously. It is found that the stable magnon-magnon entanglement, one-way steering and two-way EPR steering can be generated and controlled by atomic coherence according to the following two points: (i) the coherent coupling between magnon and atoms is established via exchange of virtual photons; (ii) the dissipation of magnon mode is dominant over amplification since one of the atomic states mediated one-channel interaction always keeps empty. The coherent control of magnon-magnon correlations provides an effective approach to modify macroscopic quantum effects using the laser-driven atomic systems.

A thin-film acoustic metamaterial absorber with tunable sound absorption characteristics.

A thin-film absorber with tunable acoustic properties over a wideband is designed based on the acoustic metamaterial theory. The thin-film acoustic metamaterial absorber (TFAMA) consists of a frame made of piezoelectric material and several flexible films with attached mass blocks (mass-spring vibration system). Based on the vibration mechanism of the mass-spring vibration system, a cellular model of local resonance form is established, and the material properties of negative effective mass are discussed. Combined with the vibration modal analysis of the coupling of mass block, elastic film, and piezoelectric material, the acoustic characteristics of the TFAMA under alternating voltage excitation are studied by finite element and experimental methods. The simulation and experimental results show that the sound wave can be well absorbed when it is incident on TFAMA to cause the membrane-cavity coupling resonance. By applying an alternating voltage to the TFAMA to excite the mass-spring vibration system to generate local resonance, the absorption of sound waves can be further enhanced in a relatively wide band near the excitation frequency. In view of the convenience of voltage parameter adjustment, the sound absorption band can be flexibly tuned in a wide range, including low frequency.

Intralesional Bacillus Calmette-Guérin injections and hypo-fractionated radiation synergistically induce systemic antitumor immune responses.

Radiotherapy, an important treatment for multiple malignancies, produces systemic anti-tumor effects in combination with immunotherapies, especially immune checkpoint inhibitors (ICBs). However, for some patients who do not respond to ICB treatment or show ICB-induced autoimmune symptoms, new alternatives need to be explored. Innovative immunomodulatory strategies, including the administration of immunostimulants, could be used to improve the immunogenicity induced by radiotherapy. In this study, we explored the synergistic effect of Bacillus Calmette-Guérin (BCG) combined with hypo-fractionated radiotherapy (H-RT) in inducing anti-tumor immune responses. We observed the systemic and abscopal effects of this combination in mice with 4 T1 breast cancer. H-RT combined with BCG could remodel the immune microenvironment and alleviate leukocyte-like responses by increasing the infiltration of CD8 + T cells, promoting the maturation of dendritic cells (DCs), decreasing the infiltration of immunosuppressive cells, and downregulating the expression of immunosuppressive cytokines. Therefore, this combination could enhance the systemic anti-tumor response, leading to the regression of untreated synchronous tumors and a decrease in the systemic metastatic burden. These results highlight the potential of BCG in assisting antitumor therapy and the therapeutic potential of this combination treatment.

Investigating the Usage Patterns of Park Visitors and Their Driving Factors to Improve Urban Community Parks in China: Taking Jinan City as an Example.

Urban community parks have significant benefits for city residents, both physical and spiritual. This is especially true in developing countries, such as China. The purpose of our study is to describe the current situation of the community parks in five main districts of Jinan City while recognizing features of the community parks that influence usage patterns. Our study also means to determine the desired improvements of visitors that promote access to and use of community parks on the basis of the Chinese context. We conducted a survey among 542 community park visitors and obtained valid responses. The findings of respondents show that community parks are mostly used by people over 55 years (34.7%) and children under 10 years (23.6%). The main motives for using community parks are for exercise (24.2%) and to socialize with others (21.6%). The majority of respondents (65.7%) rated the community park as satisfactory and considered only a few improvements needed. Regarding the desired improvements, numerous respondents mentioned adding more physical training facilities (13.3%) and activity areas (7.6%), as well as emergency call buttons in areas frequented by children and older people (7.6%). Furthermore, most of the respondents (79.9%) indicated that they would like to use the community parks more frequently if there is additional progress to make the parks more attractive, cleaner, and friendlier. These results can help park designers, government agencies, and community groups to provide the planning and design strategies for community parks to promote their upgrading in China.

Sound absorption and insulation performance of a finite cylindrical micro-perforated panel absorber.

This paper describes the theoretical prediction, simulation research, and experimental verification conducted to understand the potential of finite cylindrical micro-perforated panel absorbers (FC-MPPAs) in noise control. The simplified Rayleigh integral method is extended to predict the dissipation of sound energy in cylindrical micro-perforations with sub-millimeter aperture. The sound absorption and insulation performance of a FC-MPPA and the influence of its structural parameters on its acoustic performance were studied by model simulation and experiment, and the directional distribution of the sound field was revealed. The simulation and experimental results show that the FC-MPPA has unique acoustic characteristics different from the panel-type absorber, and its structural parameters are closely related to the acoustic-energy dissipation efficiency. Moreover, the absorption coefficient of FC-MPPA is a function of the incidence angle and frequency of the sound wave, and its acoustic properties are controlled by the coupling between the micro-perforated panel and the acoustic modes in the annular cavity domain. These studies can provide help in the design and application of FC-MPPA to achieve better noise reduction effect.

Magnon-atom-optical photon entanglement via the microwave photon-mediated Raman interaction.

We show that it is possible to generate magnon-atom-optical photon tripartite entanglement via the microwave photon-mediated Raman interaction. Magnons in a macroscopic ferromagnet and optical photons in a cavity are induced into a Raman interaction with an atomic spin ensemble when a microwave field couples the magnons to one Raman wing. The controllable magnon-atom entanglement, magnon-optical photon entanglement, and even genuine magnon-atom-optical photon tripartite entanglement can be generated simultaneously. In addition, these bipartite and tripartite entanglements are robust against the environment temperature. Our scheme paves the way for exploring a quantum interface bridging the microwave and optical domains, and may provide a promising building block for hybrid quantum networks.

Dynamic sound absorption characteristics of a series piezoelectric acoustic absorber regulated by voltage.

A piezoelectric acoustic absorber composed of double micro-perforated panels (MPPs) and their back cavity is studied in this paper. The outer layer of the MPP absorber is a common metal MPP, and the inner layer is a piezoelectric MPP made of polyvinylidene fluoride (PVDF) film. When an alternating voltage is applied to the polyvinylidene fluoride (PVDF)-micro-perforated panel (MPP), it can be excited to generate different structural vibration modes, which can bring an additional absorption peak to the absorption performance curve of the piezoelectric acoustic absorber. The numerical simulation and experimental results indicate that the frequency and sound absorption coefficient of the additional sound absorption peak are closely related to the voltage parameters. Especially when the frequency of the alternating voltage is close to the eigen-frequency of PVDF-MPP, the additional sound absorption peak is more significant. Therefore, the absorption coefficient of the piezoelectric acoustic absorber at the corresponding frequency can be effectively enhanced by appropriately adjusting the parameters of the excitation voltage. This method of selectively and specifically improving the sound absorption performance of the required frequency band is very effective in reducing the noise in the dynamic change.

The Therapeutic Effect and the Possible Mechanism of C-Phycocyanin in Lipopolysaccharide and Seawater-Induced Acute Lung Injury.

Background: Seawater drowning-induced acute lung injury (ALI) is a severe clinical condition characterized by increased alveolar-capillary permeability, excessive inflammatory response, and refractory hypoxemia. C-phycocyanin (C-PC), a biliprotein found in blue-green algae such as spirulina platensis, is widely used in the food and dietary nutritional supplement fields due to its beneficial pharmacological effects. Previous studies have revealed that C-PC has anti-inflammatory, antioxidant, and anti-apoptotic activities. Purpose: Therefore, this study investigated the protective effect and underlying mechanisms of C-PC on lipopolysaccharide (LPS) and seawater (SW) induced ALI (SW and LPS-induced ALI). Methods: An SW and LPS mouse model of ALI mice was established through intratracheal administration of 5mg/kg LPS and 25% SW. Different doses of C-PC (100, 200 and 400 mg/kg) were administered by intraperitoneal injection for seven days. In addition, gap junction communication in RAW264.7 and MLE-12 cells was determined following stimulation with 25% SW and 10 µg/ml LPS after treatment with C-PC (120 µg/ml). Moreover, the arterial partial pressure of oxygen, lung wet/dry weight ratios, total protein content and MPO levels in the bronchoalveolar lavage fluid (BALF), and the histopathologic and ultrastructure staining of the lung tissues were determined. The oxidative stress index, levels of the pro-inflammatory mediators, epithelial cell viability and apoptosis, and the regulatory effect of C-PC on the NF-κB/NLRP3 axis were investigated. Results: The results showed that C-PC significantly alleviated pathological damages, suppressed oxidative stress, inflammation and apoptosis, and enhanced the viability of epithelial cells in the lung tissues. Furthermore, C-PC was shown to inhibit activation of the NF-κB/NLRP3 pathway and the formation of the NLRP3 inflammasome complex. Conclusions: In conclusion, C-PC shows promising therapeutic value in SW and LPS-induced ALI/ARDS, providing new insight into ALI/ARDS treatment.

A Co-Nanoparticles Modified Electrode for On-Site and Rapid Phosphate Detection in Hydroponic Solutions.

Conventional strategies for determining phosphate concentration is limited in efficiency due to the cost, time, and labor that is required in laboratory analysis. Therefore, an on-site and rapid detection sensor for phosphate is urgently needed to characterize phosphate variability in a hydroponic system. Cobalt (Co) is a highly sensitive metal that has shown a selectivity towards phosphate to a certain extent. A disposable phosphate sensor based on the screen-printed electrode (SPE) was developed to exploit the advantages of Co-nanoparticles. A support vector machine regression model was established to predict the concentration of phosphate in the hydroponic solutions. The results showed that Co-nanoparticles improve the detection limit of the sensor in the initial state. Meanwhile, the corrosion of Co-nanoparticles leads to a serious time-drift and instability of the electrodes. On the other hand, the coefficient of variation of the disposable phosphate detection chip is 0.4992%, the sensitivity is 33 mV/decade, and the linear range is 10-1-10-4.56 mol/L. The R2 and mean square error of the buffer-free sensor in the hydroponic solution are 0.9792 and 0.4936, respectively. In summary, the SPE modified by the Co-nanoparticles is a promising low-cost sensor for on-site and rapid measurement of the phosphate concentration in hydroponic solutions.

Simulation-Based Design and Optimization of Rectangular Micro-Cantilever-Based Aerosols Mass Sensor.

Micro-Cantilever (MCL) is a thin film structure that is applied for aerosol particle mass sensing. Several modifications to the rectangular MCL (length-to-width ratio, slots at the anchor, serrations at its side edges) are made to deduce the role and influence of the shape of rectangular MCL-based aerosol mass sensors and reduce gas damping. A finite element fluid-structure interaction model was used to investigate the performance of MCL. It is found that (I) the mass sensitivity and quality factor decline with the increasing of length-to-width ratio which alters the resonant frequency of the MCL. The optimum conditions, including the length-to-width ratio (σlw = 5) and resonant frequency (f0 = 540.7 kHz) of the MCL, are obtained with the constant surface area (S = 45,000 µm2) in the frequency domain ranging from 0 to 600 kHz. (II) The slots can enhance the read-out signal and bring a small Q factor drop. (III) The edge serrations on MCL significantly reduce the gas damping. The results provide a reference for the design of aerosol mass sensor, which makes it possible to develop aerosol mass sensor with high frequency, sensitivity, and quality.

High sensitivity field asymmetric ion mobility spectrometer.

A high sensitivity field asymmetric ion mobility spectrometer (FAIMS) was designed, fabricated, and tested. The main components of the system are a 10.6 eV UV photoionization source, an ion filter driven by a high voltage/high frequency n-MOS inverter circuit, and a low noise ion detector. The ion filter electronics are capable to generate square waveforms with peak-to-peak voltages up to 1000 V at frequencies up to 1 MHz with adjustable duty cycles. The ion detector current amplifier has a gain up to 1012 V/A with an effective equivalent input noise level down to about 1 fA/Hz1/2 during operation with the ion filter at the maximum voltage and frequency. The FAIMS system was characterized by detecting different standard chemical compounds. Additionally, we investigated the use of a synchronous modulation/demodulation technique to improve the signal-to-noise ratio in FAIMS measurements. In particular, we implemented the modulation of the compensation voltage with the synchronous demodulation of the ion current. The analysis of the measurements at low concentration levels led to an extrapolated limit of detection for acetone of 10 ppt with an averaging time of 1 s.

[Study on Error Analysis of Nonlinear Function Coefficient of FAIMS].

The solution of ion mobility's nonlinear function coefficients α2 and α4 is the basis for achieving substance identification of High Field Asymmetric waveform Ion Mobility Spectrometry (FAIMS). Currently, nonlinear function coefficients α2 and α4 lack priors, meanwhile, existed solving results about α2 and α4 are deficient in error evaluation standard. In this article, acetone, isopropanol and 1, 2-dichlorobenzene were detected under different dispersion voltage by homemade FAIMS. In general, the spectrum peak of same sample at different dispersion voltage value is unique. Different dispersion voltage and corresponding compensation voltage value determines the value of α2 and α4. According to sample spectra at different dispersion voltage value, groups of spectral characteristics were obtained. Affirmatory number of data which were selected from multiple sets of compensation voltage value and dispersion voltage value, so that they were utilized to solved out lots of α2 and α4. Lots of factor have an effect on the accuracy of the solving results of α2 and α4, for instance, value of compensation voltage and dispersion voltage, style of fetching points of dispersion voltage, and so on. Comparing to other factors, style and amount of dispersion voltage is likely to control. By data analyzing huge amounts of α2 and α4 data, this paper explored their characteristic of distribution and correlation about them, research influence of number and method to fetch dispersion voltage detected points for error of solving results. After fitting frequency of α2 and α4, it was found that they conform to normal distribution, goodness of fitting exceed 0. 96, thus standard deviation of their distribution are able to evaluate error of solving results. In addition, a strong correlation exists between them, relevance of sample is -0. 977, -0. 968, -0. 992 respectively. With increasing of computing selected points, the corresponding error of solving results decrease. By comparing the standard deviation of method to fetch dispersion voltage detected points, found that detecting frequency in case of detecting maximum and the 70% of maximum of dispersion voltage value is lower at approximately same standard deviation, solving effect was optimized in unique fetching points style. Based on the premise of ensuring the accuracy of solving results of α2 and α4, it is obvious that reducing the frequency of detections for FAIMS effectively. It created favorable conditions for rapid field detection and precise spectral analysis.

[The solution of nonlinear function of ion mobility based on FAIMS spectrum peak position].

FAIMS's ion separation mechanism is based on analyte's characteristic nonlinear relationship between its ion mobility and applied electric field strength. Present characterization methods for this nonlinear relationship are based on precarious assumptions which incur substantial errors under many circumstances. A rigorous method for solving the second and fourth taylor series coefficient of this relationship based on dispersion voltage value (assuming half-sinusoidal waveform) and associated compensation voltage value of spectrum peak is presented, alongside with rigorous analytical functions. FAIMS spectrums were obtained for ethanol, metaxylene and n-butanol using custom-built FAIMS spectrometer, and corresponding second and fourth taylor series coefficients were obtained with the proposed method. Evaluation shows that this method substantially reduces the RMS error between interpolated and measured peak compensation voltage values under different dispersion voltages, confirming its superiority over present methods. This rigorous method would help improve spectral resolutions of FAIMS spectrometer, facilitating high precision FAIMS spectrum database construction and accurate analyte discrimination.

[FAIMS of trace volatile organic compounds].

FAIMS is a fast and high sensitive technique for detecting trace volatile organic compounds. Spectra of acetone, benzene and toluene were obtained on a homemade high-field asymmetric waveform ion mobility spectrometer and they can be easily separated in the spectra. Three xylene isomeric compounds were also successfully separated in FAIMS. Effect of carrier gas flow rate on the ion intensity was analyzed, and the optimal flow rate of carrier gas was 220 L x h(-1) which can be used for the optimization of FAIMS instrument. The detection limit for acetone is 100 ng x L(-1) that is an order of magnitude lower than the foreign traditional IMS.

[Filariasis elimination in Zoucheng City of Shandong Province: measures and effect].

Zoucheng was a high endemic area of bancroftian filariasis with Culex pipiens pallens as the principal transmitting vector. Transmission of the disease was interrupted in 1981. Epidemiological surveillance has been then carried out. After 1989, parasitological and immunological examinations were conducted for those cases previously with and without microfilaremia, entomological surveillance was also carried out. Results showed that the antibody level in inhabitants has been at normal level, and no infection has been found in mosquitoes.

[Technology and prospects of noninvasive blood glucose measurement].

Non-invasive (NI) blood glucose measurement is a new method, this article deals with current researches and analyzes the advantages and shortages of different measurement methods, including electrochemical process and Optical methods (transmission, polarimetry and back scattering). Then, the technology of near-infrared spectra is emphasized in the analysis. Finally, the problem and technical analysis of non-invasive (NI) blood glucose measurement at the present time are discussed. We preliminarily aim at the method of NI blood glucose determination and the original concept of measuring apparatus, including the choice of incident light wavelength, determination of receiver point, establishment of the optical model of biological tissue, and apparatus design.