Economic Policy Uncertainty and Corporate Mergers and Acquisitions

In recent years, the frequent adjustment of the government’s economic policies and the uncertainty of foreign economic situations have made the degree of uncertainty of China’s economic policies rise continuously. The increasing degree of policy uncertainty will inevitably affect the investment and financing decisions of micro enterprises. Then, how does economic policy uncertainty (EPU) affect mergers and acquisitions (M&A) behavior? What’s the mechanism? Based on the above questions, this paper uses the data of non-financial listed companies in the Shanghai and Shenzhen stock exchanges from 2008 to 2018 as a sample to explore the relationship between EPU and M&A. The study shows that rising EPU will promote corporate M&A behavior, and this effect is more significant in slow-growth companies. The relationship between EPU and M&A is affected by corporate governance, stock price volatility and financing constraints. Specifically, the company’s M&A size is more sensitive to EPU with higher level of corporate governance, higher level of stock price volatility, and lesser financing constraints. Further research shows that the rise of EPU will significantly promote the improvement of M&A performance in the short-term, but this effect does not exist in the long-term. Various robustness checks do not change the empirical results of this paper

A rapid VEGF-gene-sequence photoluminescence detector for osteoarthritis

Osteoarthritis (OA) has become a serious problem to the human society for years due to its high economic burden, disability, pain, and severe impact on the patient’s lifestyle. The importance of current clinical imaging modalities in the assessment of the onset and progression of OA is well recognized by clinicians, but these modalities can only detect OA in the II stage with significant structural deterioration and clinical symptoms. Blood vessel formation induced by vascular endothelial growth factor (VEGF) occurs in the early stage and throughout the entire course of OA, enables VEGF relating gene sequence to act as a biomarker in the field of early diagnosis and monitoring of the disease. Here in, a facile rapid detection of VEGF relating ssDNA sequence was developed, in which manganese-based zeolitic imidazolate framework nanoparticles (Mn-ZIF-NPs) were synthesized by a simple coprecipitation strategy, followed by the introduction and surficial absorption of probe ssDNAs and the CRISPR/Cas12a system components. Furthermore, fluorescence experiments demonstrated that the biosensor displayed a low detection limit of 2.49 nM, a good linear response to the target ssDNA ranging from 10 nM to 500 nM, and the ability of distinguishing single nucleotide polymorphism. This finding opens a new window for the feasible and rapid detection of ssDNA molecules for the early diagnose of OA

Association of epidural analgesia during labor and early postpartum urinary incontinence among women delivered vaginally: a propensity score matched retrospective cohort study

Abstract Background Although epidural analgesia is considered the gold standard for pain relief during labor and is safe for maternity and fetus, the association between the epidural analgesia and pelvic floor disorders remains unclear. Thus we estimate the association between epidural analgesia and early postpartum urinary incontinence (UI). Methods A propensity score-matched retrospective cohort study was conducted at a university-affiliated hospital in Shanghai, China. Primiparous women with term, singleton, and vaginal delivery between December 2020 and February 2022 were included. UI was self-reported by maternity at 42 to 60 days postpartum and was classified by International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form (ICIQ-UI SF). Using logistic regression models, the associations between epidural analgesia and early postpartum UI were assessed. Results Among 5190 participants, 3709 (71.5%) choose epidural anesthesia during labor. Analysis of the propensity-matched cohort (including 1447 maternal pairs) showed epidural anesthesia during labor was independently associated with UI in early postpartum period (aOR 1.50, 95% CI 1.24–1.81). This association was mainly contributed to stress UI (aOR 1.38, 95% CI 1.12–1.71) rather than urge UI (aOR 1.45, 95% CI 0.99–2.15) and mixed UI (aOR 1.52, 95% CI 0.95–2.45). Furthermore, we observed that the association between epidural anesthesia and UI was more pronounced among older women (≥ 35 y) and women with macrosomia (infant weight ≥ 4000 g), compared with their counterparts (both P for interaction < 0.01). After further analysis excluding the women with UI during pregnancy, the results remained largely consistent with the main analysis. Conclusions The findings support that epidural anesthesia was associated with SUI in the early postpartum period

Effect of Ultrafast Broadband Nonlinear Optical Responses by Doping Silver into Ti3C2 Nanosheets at Visible Spectra

Ti3C2 nanosheet is a newly discovered two-dimensional (2D) clan. It turns out to have encouraging applications for electromagnetic shielding and energy storage. Here, Ag@ Ti3C2 hybrids are precisely synthesized by using the one-step solution processing method. Also, their ultrafast broadband nonlinear optical responses in the visible region are studied systematically through nanosecond open-aperture Z-scan and transient absorption techniques. The mechanism of two-photon absorption (TPA) is disclosed in the visible region (409&ndash;532 nm). When the laser energy is low and the wavelength is longer than 400 nm, nonlinear absorption cannot happen. Meanwhile, as the laser energy increases, two photons will be absorbed by the electrons in the valence band and the electrons will jump to the conduction band. The process is named as two-photon absorption which will make the specimen show reverse saturable absorption (RSA) properties. What is more, the ultrafast carrier dynamics of the specimen are studied by using the transient absorption. The result shows that the decay contains two phases: the fast and then the slow one. The two phases first come from electron&ndash;phonon and then from phonon&ndash;phonon interactions, respectively. The electron transfer and charge carrier trapping processes are further verified by the outcomes of similar measurements on Ag@ Ti3C2 hybrids. Besides, the two decay processes increase together with the pump fluence. These results show that Ti3C2 nanosheet has potential applications in broadband optical limiter

MAGNETIC FIELD DESIGN OF THE BAPS HIGH PRECISION QUADRUPOLE MAGNET

Abstract The Beijing Advanced Photon Source (BAPS) is a high performance light source planned to be constructed in China. High precision small aperture quadrupole magnets are required in the BAPS storage ring, which need extremely high mechanical accuracy. Instead of the conventional manufacture method, the coils are comprised of several U-shaped solid copper sheets. So two-piece structure of the iron core can be adopted to reduce assembly error and improve the poles symmetry. Design considerations, 2D and 3D magnetic field calculations are presented in detail, and the needed mechanical precision is estimated according to the error field analysis

Position Measurement Based on Fisheye Imaging

For the omnidirectional measurement, the collected images of large-angle fisheye lens need to be corrected and spliced before next procedure, which is complicated and inaccurate. In this paper, a direct position measurement method based on fisheye imaging is proposed for large-angle imaging without any image correcting and splicing. A nonlinear imaging system of fisheye lens is used to acquire the sequence images based on its distortion model, and the critical distortion features of the sequence images are extracted, which contains the position information. And a BP neural network is trained with the extracted image features of previous standard experimental dataset. Finally, the trained BP neural network is employed to measure the object’s distance. Experimental results demonstrate show that the proposed method achieves simple close-object distance measurement with high robustness and a measurement error of ±0.5cm. The proposed method overcomes the shortcomings of conventional measurement methods and expands the fisheye applications filed for omnidirectional measurement

Recent Progress in Electrochemical Nano-Biosensors for Detection of Pesticides and Mycotoxins in Foods

Pesticide and mycotoxin residues in food are concerning as they are harmful to human health. Traditional methods, such as high-performance liquid chromatography (HPLC) for such detection lack sensitivity and operation convenience. Efficient, accurate detection approaches are needed. With the recent development of nanotechnology, electrochemical biosensors based on nanomaterials have shown solid ability to detect trace pesticides and mycotoxins quickly and accurately. In this review, English articles about electrochemical biosensors in the past 11 years (2011–2022) were collected from PubMed database, and various nanomaterials are discussed, including noble metal nanomaterials, magnetic metal nanoparticles, metal–organic frameworks, carbon nanotubes, as well as graphene and its derivatives. Three main roles of such nanomaterials in the detection process are summarized, including biomolecule immobilization, signal generation, and signal amplification. The detection targets involve two types of pesticides (organophosphorus and carbamate) and six types of mycotoxins (aflatoxin, deoxynivalenol, zearalenone, fumonisin, ochratoxin A, and patulin). Although significant achievements have been made in the evolution of electrochemical nano-biosensors, many challenges remain to be overcome

Association of cesarean delivery timing with pelvic floor muscle function and urine incontinence: A propensity score‐matched study

Abstract Pelvic floor dysfunction is a common gynecological disease that adversely affects women's quality of life and mental health. Delivery is considered a significant independent risk factor for pelvic floor dysfunction. Surface electromyography (sEMG) values for the pelvic floor muscles (PFM) have been shown to differ according to different delivery modes. This study aimed to compare sEMG results between intrapartum and antepartum cesarean delivery (CD), 42–60 days after delivery. Data of women who underwent CD at the International Peace Maternity and Child Health Hospital were collected from September 2021 to December 2021. Myotrac Infiniti System was used to measure the electromyographic activity of PFM after 42–60 days of parturition. Propensity score matching (1:1) was applied to achieve a balance in baseline data between the two groups (intrapartum and antepartum CD). A total of 200 paired cases were selected for statistical analysis. In the propensity score‐matched analysis, there were no statistically significant differences in PFM sEMG between women with antepartum or intrapartum CD (p > 0.05 for all). We observed similar results with postpartum urinary incontinence (24 [12.0] vs. 21 [10.5]; adjusted odds ratio (aOR), 1.12 [95% confidence interval (CI) 0.60–2.12]; p = 0.717) and stress urinary incontinence (12 [6.0] vs. 14 [7.0]; aOR, 0.80 [95% CI 0.35–1.80]; p = 0.596) as outcomes. After excluding participants with intrapartum CD when the cervix was dilated <6 cm, all sEMG of PFM had a comparable level of risk in both the antepartum and intrapartum CD groups. There were no significant differences in sEMG of the PFM and the incidence of urinary incontinence between patients undergoing intrapartum or antepartum CD. Excluding women who underwent intrapartum CD when the cervix was dilated to <6 cm produced little change in results. Thus, different opportunities for CD may not impact the sEMG of the PFM and the incidence of urinary incontinence