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In this article, we examine corporate investment decisions in a model with short selling. We show that high short‐selling activities can cause firms to overinvest and that the agency problems between managers and shareholders drive this overinvestment. Empirically, we find that short interest is positively associated with subsequent corporate investment and that the effect of short‐selling activities on investment is stronger when the sensitivity of chief executive officer compensation to stock price performance is greater. The results are not explained by short‐sale constraints or firm overvaluation. Additionally, short‐selling‐induced corporate investments can partly explain the negative relation between both short interest and corporate investment with subsequent stock returns.

Astragalus variabilis Bunge is a widespread locoweed that threatens livestock production in desert grassland. No research has reported its possible ecological functions due to focus being on its negative effect on livestock production. This study aimed to assess the effects of A. variabilis on soil properties and its possible role in improving soil quality in desert grassland. Soil samples were collected in Astragalus patches and the adjacent bare patches over two successive growing seasons in Alxa desert grassland where A. variabilis was favoured to spread. Soil properties including texture, water content, dry bulk density, porosity, available nutrients, organic matter, and soil microbial biomass were determined at 15 study sites. There was no significant difference in soil texture between Astragalus-dominant and bare patches; but organic matter (OM), available N and P, and microbial biomass in surface soil (0–30cm) were significantly higher in Astragalus patches. Furthermore, microbial biomass showed a significantly positive correlation with available nutrients and OM. Levels of water soluble salt were significantly lower in A. variabilis surface soils under drought conditions. Results suggested that A. variabilis was associated with some positive changes in soil properties, and was potentially important in improving soil chemical and microbial properties in desert grassland ecosystems. Consequently, total elimination of locoweed should not necessarily be considered the best solution to locoweed poisoning in livestock.

We study how conflicts within a lending syndicate affect loan contract and syndicate formation. We argue that loan provisions serve an important dual function: In addition to moderating borrower–lender conflicts, they reduce within‐syndicate conflicts. We show that greater potential for within‐syndicate conflicts is associated with more and stricter covenants. Loans are less restrictive when the interests of participants and the lead arrangers are better aligned, for example, when participant–banks have stronger relationships with the lead arranger or hold borrower's equity (indirectly). Overall, our results show that covenant choice, syndicate formation, and lead arranger's loan allocation all play an important role in reducing within‐syndicate conflicts.

Hederagenin (HED) has poor anticancer activity whose mechanism remains unclear and unsystematic. Free drugs for cancer treatment exhibit disadvantages such as poor targeting and efficacy. To address this problem, we constructed a nanoplatform of black phosphorus quantum dots (BPQDs) camouflaged with a platelet membrane (PLTm) carrying HED, termed PLT@BPQDs-HED. PLTm vesicles serve as a shell to encapsulate multiple high-efficiency drug-loaded nanocores, which can target tumor sites and significantly improve antitumor activity. Compared with free HED, this platform significantly reduced tumor cell viability and the mitochondrial membrane potential (MMP), while increasing the production of intracellular reactive oxygen species (ROS). The platform also significantly increased the amounts of terminal deoxyribonucleotide transferase mediated dUTP nick-end-labeling (TUNEL)-positive cells and decreased the number of Ki-67-positive cells. In addition, the platform upregulated proapoptotic factor Bax, downregulated the anti-apoptotic molecule Bcl-2, activated Caspase-9 and Caspase-3, and stimulated Cytochrome C release. Moreover, the platform promoted the formation of autophagosomes, upregulated Beclin-1, and promoted LC3-I conversion into LC3-II. This study demonstrated that the above platform significantly enhances tumor targeting and promotes mitochondria-mediated cell apoptosis and autophagy in tumor cells.

High-speed motorized spindle is the core component of high-speed machining machine tools, and thermal error is the main factor affecting the machining accuracy of the motorized spindle. Reducing thermal error has become the most important research topic in the case of motorized spindles. The development status of the cooling strategy of the motorized spindle is explored, and the methods to improve the cooling efficiency of the motorized spindle are discussed. Some representative research results of the cooling strategy of motorized spindles at home and abroad are reviewed. Based on summarizing the related research results on cooling strategies for the core components, such as the stator, rotor and bearing of the motorized spindle, this paper analyzes the advantages and disadvantages of various cooling strategies and their applicable working conditions, and the future development direction of motorized spindle cooling strategies is discussed. The combination of various channel structures and the cooling strategy of the stator outer ring of the motorized spindle will improve the cooling efficiency of the motorized spindle, and research on the motorized spindle core cooling will become more and more important. In addition, the cooling system of the motorized spindle bearing, stator, and rotor can be improved at the same time, and the heating problem of the motorized spindle can be solved.

The coronavirus disease 2019 (COVID-19), caused by a novel virus of the beta-coronavirus genus (SARS-CoV-2), has spread rapidly, posing a significant threat to global health. There are currently no drugs available for effective treatment. Severe cases of COVID-19 are associated with hyperinflammation, also known as cytokine storm syndrome. The reduce inflammation are considered promising treatments for COVID-19. Necroptosis is a type of programmed necrosis involved in immune response to viral infection, and severe inflammatory injury. Inhibition of necroptosis is pivotal in preventing associated inflammatory responses. The expression of key regulators of the necroptosis pathway is generally up-regulated in COVID-19, indicating that the necroptosis pathway is activated. Thus, necroptosis inhibitors are expected to be novel therapeutic candidates for the treatment of COVID-19.

Background: 3D printing is a kind of rapid prototyping technology. It is a digital model file-based technology that uses powdered metals, plastics, and other bond able materials to construct objects by stacking them layer by layer. In recent years, 3D printed artificial bones have been widely used for repairing or replacing damaged bones. Therefore, the application of 3d printing technology in the field of orthopedics has attracted more and more attention. Objective: This paper introduces the research status of 3D printing technology in the field of orthopedics and discusses the future development direction. Methods: Summarize various representative patents related to 3D printing bones all over the world. Results: By summarizing a large number of patents related to 3D printing bones, the research status of printing devices, printing materials, structure optimization, and related applications of 3D printing bones are analyzed, and the related problems and development trends of 3D printing bones are discussed. Conclusion: The combination of 3D printed bone materials and the optimization of the artificial bone unit structure will improve the mechanical properties of bone grafts and increase the success rate of transplantation. Bone repair aids and surgical guides will improve the success rate of orthopedic surgery and will be more widely used in the future. 3D printing technology is more and more widely used in the field of orthopedics, and there will be more research results in the future.

Abstract: This paper presents a synthetic U-Pb and Hf isotopic study of zircons and a whole-rock geochemical study on diabase swarms that were emplaced into the Proterozoic formations in the Xuzhou-Huaibei area, the southeast margin of North China Craton. Zircons from the diabase dykes display weak oscillatory zoning in the cathodoluminescence (CL) images and show high Th/U ratios (0.91–6.90), both of which are typical of a magmatic origin. The SHRIMP and Q-ICP-MS U-Pb zircon dating results indicate that the diabase swarms were emplaced at ca. 890 Ma. Hf isotopic analysis on these zircons gives ɛ Hf(t) values ranging from 2.26 to 14.74 and Hf model age t DM1 and t DM2 ranging from 843 to 1321 Ma and from 808 to 1779 Ma, respectively. Geochemically, the diabase swarms are characterized by a relative enrichment in LREE and LILE (Rb, Ba and La), a comparative enrichment in Cr and Ni, but a slight depletement in HFSE (Th, Nb, Ta, Zr and Hf). They are plotted in the within-plate tholeiite series on the tectonic discrimination diagrams. Taken together, these geochemical and isotopic data suggest that the primary magmas to form the diabase dykes in the Xuzhou-Huaibei area could have been derived from a transitional mantle in the Mesoproterozoic, and were most probably emplaced under a continental margin extensional setting at ca. 890 Ma. The results of this study demonstrate that the Neoproterozoic (800–900 Ma)magmatism was not restricted to the Yangtze Block, but also occurred at the southeast margin of the North China Craton.

We study the implications of market segmentation in a domestic setting, the US municipal bond market. A (state‐level) segmentation of this market emerges from asymmetric tax exemption. Municipal bond investors are exempt from state and local taxes on bonds issued by their own state, but not on bonds issued by other states. We demonstrate that market segmentation imposes significant costs on both issuers and investors in the form of higher yields and higher costs of financial intermediation. Our results provide insight into some well‐documented artifacts of the municipal bond market, such as high yields and the popularity of insurance.

This paper studies the impact of corporate headquarters location on capital structure policies. We show that firms exhibit conformity in their financing policies to those of geographically proximate firms and that the location of corporate headquarters helps explain the cross‐sectional variation of capital structure in the United States. The location effect is robust to local credit market conditions and to state laws on corporate takeover and payout restrictions. The results suggest that noneconomic factors, such as local culture and social interactions among corporate executives, play a significant role in influencing corporate financial policies of firms headquartered in the same metropolitan area.

We examine the effect of the Efficient Market Hypothesis (EMH) on the investment behavior of mutual fund managers. We show that managers who are more likely to be exposed to the ideas of EMH throughout their higher education are more “passive” than their unexposed peers: they are more likely to manage index funds, and when managing active funds, they hold portfolios with larger numbers of stocks and deviate less from their investment benchmarks. Exposed managers, however, take more systematic risks. Although academic exposure to the EMH does not result in better performance, it helps professional investors generate capital inflows.

Molecule imprinting polymers (MIPs) with high chiral selectivity for N^α-protected amino acids were synthesized in polar solvent using acrylamide (AM) or combined functional monomer methacrylic acid (MAA) + vinyl pyridine (VP). Factors that influence the chiral selectivity of MIPs and mechanisms of the chiral recognition process were investigated. It was found that the rigid structure and the polar functional group of the print molecule were very important for the chiral selectivity of MIPs. For MIPs made using a combined functional monomer, ionic and hydrophobic interaction may be responsible for the chiral recognition process in aqeous media. The number of binding sites on MIPs and dissociation constants for the complex of enantiomers and MIPs were determined by frontal chromatography analysis. Copyright © 1999 John Wiley & Sons, Ltd.

In order to make a molecule imprinting polymer (MIP) with highly chiral selectivity against N-t-Boc-l-Trp, a new kind of “cocktail” functional monomer: acrylamide+2-vinylpyridine was investigated. The MIP showed impressive chiral selectivity (α=3.23). With the increasing of water content in the mobile phase, ionic and hydrophobic interaction were found to be responsible for the chiral recognition process instead of the hydrogen bond. Tailing and peak asymmetry problems were overcome by using linear gradient elution. Physical properties such as thermal stability and pore structure for the MIP were also investigated.

Molecule imprinting polymers (MIPs) with high chiral selectivity for Nα‐protected amino acids were synthesized in polar solvent using acrylamide (AM) or combined functional monomer methacrylic acid (MAA) + vinyl pyridine (VP). Factors that influence the chiral selectivity of MIPs and mechanisms of the chiral recognition process were investigated. It was found that the rigid structure and the polar functional group of the print molecule were very important for the chiral selectivity of MIPs. For MIPs made using a combined functional monomer, ionic and hydrophobic interaction may be responsible for the chiral recognition process in aqeous media. The number of binding sites on MIPs and dissociation constants for the complex of enantiomers and MIPs were determined by frontal chromatography analysis. Copyright © 1999 John Wiley & Sons, Ltd.

Austenite grain size plays an important role for quenched and tempered A517 GrQ rack steel. In order to investigate the austenite grain growth behavior, in-situ austenizing experiments were conducted at different temperatures with varied holding time. Austenite grain growth, and subsequent bainite and martensite transformation were observed by a confocal laser scanning microscope (CLSM). The average austenite grain size increased rapidly from 32.7 um to 137.9 um with increasing temperature from 1100 degC to 1250 degC, and abnormal grain growth occurred at 1250 degC for 15 min. While holding from 5 min to 20 min at 1200 degC, the grain size grew gradually from 70.2 um to 84.8 um. The grain size distributions under different conditions all obey lognormal function. After austenizing, the rate of subsequent cooling has an significant impact on transformation process. The transformation duration time decreased from over 142 s to 11 s with increasing cooling rate at 1 degC/s and 5 degC/s, which could be corresponding to bainite and martensite transformation respectively.

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