Different from conventional materials, materials with negative Poisson's ratios expand laterally when stretched longitudinally. Known as ‘auxetic’ materials, the effect means they possess ...particularly fascinating properties, which have recently attracted considerable attention in the literature. A range of auxetic materials has been discovered, theoretically designed and fabricated. Developments in additive manufacturing (AM) techniques enable fabrication of materials with intricate cellular architectures. This paper outlines recent progress in the development of auxetic materials and structures, and their mechanical properties under quasi-static and dynamic loading are analysed and summarised. Limited experimental studies on 3D printed auxetic materials and structures are given more attention, ahead of extensively finite element (FE) simulations. A special focus is dedicated to their large, plastic deformation behaviour and energy absorption performance, which should be stressed in their engineering applications; no review paper has yet been found regarding this. Finally, this paper provides an overview of current study limitations, and some future research is envisaged in terms of auxetic materials and structures, nano-auxetics and additive manufacturing.
•This paper outlines recent development of auxetic materials and structures.•Limited experimental studies on printed auxetic materials and structures are given more attention.•A special focus is their large deformation behaviour and energy absorption performance.•This paper summaries current limitations and future research regarding AM, auxetic materials and nano-auxetics.
Do political connections buffer firms from or bind firms to the government? To examine this theoretical puzzle, we distinguish two types of managerial political connections,
ascribed
and
achieved
, ...and theorize that these different types of ties either buffer firms from or bind firms to government demands. Furthermore, we propose that these effects are contingent on both industrial and regional institutional conditions. We test our framework with a unique panel data set of privately controlled listed firms’ charitable donations in China from 2001 to 2012. We find that firms whose executives have ascribed bureaucratic connections are more likely to use their connections as a buffer from governmental donation pressure, particularly in competitive industries and less market-oriented regions, whereas in state-monopolized industries this buffering effect is reduced. In contrast, achieved political connections are more likely to serve a binding function that facilitates donation, particularly in state-monopolized industries and more market-oriented regions, but in less market-oriented regions, they buffer firms from the pressure to donate. Our research contributes to the literatures on the effects of political connections, the institutional contingencies of political connections, and the relationship between corporate social responsibility (CSR) and corporate political activities (CPA).
Metal‐oxide photocatalysts have demonstrated great potential in photocatalytic H2O2 production. This review focuses on metal‐oxide‐based photocatalytic materials for H2O2 production and ...systematically discusses their pros and cons, modification strategies for enhanced performance, and prospects on future research directions. This review also summarizes the quantification methods for H2O2 and associated intermediates to provide guidance for future research in this area.
Hydrogen peroxide (H2O2) is a mild but versatile oxidizing agent with extensive applications in bleaching, wastewater purification, medical treatment, and chemical synthesis. The state‐of‐art H2O2 production via anthraquinone oxidation is hardly considered a cost‐efficient and environment‐friendly process because it requires high energy input and generates hazardous organic wastes. Photocatalytic H2O2 production is a green, sustainable, and inexpensive process which only needs water and gaseous dioxygen as the raw materials and sunlight as the power source. Inorganic metal oxide semiconductors are good candidates for photocatalytic H2O2 production due to their abundance in nature, biocompatibility, exceptional stability, and low cost. Progress has been made to enhance the photocatalytic activity toward H2O2 production, however, H2O2 photosynthesis is still in the laboratory research phase since the productivity is far from satisfaction. To inspire innovative ideas for boosting the H2O2 yield in photocatalysis, the most well‐studied metal oxide photocatalysts are selected and the modification strategies to improve their activity are listed. The mechanisms for H2O2 production over modified photocatalysts are discussed to highlight the facilitating role of the modification methods. Besides, methods for the quantification of H2O2 and associated radical intermediates are provided to guide future studies in this field.
While research on the disclosure of CSR (corporate social responsibility) recognizes the influence of government regulations and guidelines, less attention has been given to the co-existence of ...conflicting pressures from the state. We develop a framework wherein CSR reporting is viewed as an organizational response to institutional complexity that arises from the conflicting demands from the central government and local governments, and apply it to publicly listed firms in China after the central government agencies issued guidelines on CSR reporting. Some provincial governments' high priority given to short-term GDP growth created tension with the central government's expectations on CSR reporting. Firms with attributes that increase scrutiny from both institutional constituencies experienced heightened tension, and they responded with early adoption but low-quality reports. Our framework was supported through a longitudinal analysis between 2008 and 2011. Our study contributes to the literature on CSR disclosure by uncovering the impact of conflicting government pressures, and advances research on institutional complexity by identifying a specific decoupling response.
Abstract
Background
Traditional silicone implants used in augmentation rhinoplasty lead to postoperative complications.
Objectives
To introduce a novel silicone implant designed to reduce ...postoperative complications.
Methods
The author designed a novel modification for the traditional silicone nasal implant, which has a particle surface, vertical and horizontal grooves, and a special vertical board to support the nasal tip. A total of 114 consecutive clinical cases were retrospectively reviewed from September 2016 to November 2022, with a minimum of 36 months and an average 51 months of follow-up. All patients underwent augmentation rhinoplasty using this novel implant, with 97 (85.09%) patients using only the silicone and 17 (14.91%) the silicone implant with conchal cartilage. Surgical complications such as sliding down, redness, extrusion, deviation, translucency, capsular contracture, or infection were recorded.
Results
The median patient age was 28 (range, 18-55) years, with 109 female and 5 male patients. Among the 114 cases, 46 (40.35%) involved primary surgery and 68 (59.65%) involved revisional surgery. The overall complication rate was 4.39%, and 0.88% of the patients had slight redness, 0.88% had intermittent pain, and 2.63% had infections. No other complication was observed, and all complications occurred in revisional surgeries. A total of 109 patients (95.61%) showed satisfying results without any postoperative complication. None of the patients with primary surgery reported postoperative complications.
Conclusions
The novel silicone nasal implant can effectively reduce the rate of postoperative complications. Therefore, augmentation rhinoplasty using this implant enables a more natural-looking outcome.
Level of Evidence: 3
A significant gap exists in our understanding of what explains the varying responses of multinational corporations (MNCs) to social issues in emerging markets. Arguably, in a setting where both ...market institutions and regulations and norms of corporate social responsibility are underdeveloped, it is more difficult for corporations to take actions beyond those that serve their immediate economic interests. Proposing a social movement perspective on MNCs’ responsiveness to social issues in emerging markets, we identify the mechanisms by which online activists grab firms’ attention and force them to become more socially responsive. A perception of organizational vulnerability and a home-country institutional logic that is consistent with the demands of the online campaign provide political opportunity structures that hasten the corporate response but affect the magnitude of firm response differently. We test our framework in the empirical context of corporate philanthropic action following the 2008 earthquake in Sichuan province in China, which triggered an online campaign that questioned MNCs’ donations to the disaster relief effort. Our study contributes to the literature on heterogeneous organizational responses to social movements, a better understanding of the antecedents for MNCs’ social responsiveness in emerging markets, and research on MNCs.
The interaction between a co‐catalyst and photocatalyst usually induces spontaneous free‐electron transfer between them, but the effect and regulation of the transfer direction on the ...hydrogen‐adsorption energy of the active sites have not received attention. Herein, to steer the free‐electron transfer in a favorable direction for weakening S−Hads bonds of sulfur‐rich MoS2+x, an electron‐reversal strategy is proposed for the first time. The core–shell Au@MoS2+x cocatalyst was constructed on TiO2 to optimize the antibonding‐orbital occupancy. Research results reveal that the embedded Au can reverse the electron transfer to MoS2+x to generate electron‐rich S(2+δ)− active sites, thus increasing the antibonding‐orbital occupancy of S−Hads in the Au@MoS2+x cocatalyst. Consequently, the increase in the antibonding‐orbital occupancy effectively destabilizes the H 1s‐p antibonding orbital and weakens the S−Hads bond, realizing the expedited desorption of Hads to rapidly generate a lot of visible H2 bubbles. This work delves deep into the latent effect of the photocatalyst carrier on cocatalytic activity.
To create a beneficial transfer direction for cultivating moderate hydrogen‐atom adsorption/desorption on a co‐catalyst, an electron‐reversal strategy is proposed that optimizes the antibonding‐orbital occupancy. The embedded Au can reverse the free‐electron transfer to MoS2+x to form electron‐rich S(2+δ)−, which causes an increased antibonding‐orbital occupancy, thus weakening S−Hads bonds for photocatalytic H2 evolution.
Millimeter wave (mmwave) communications have attracted increasing attention thanks to the abundant spectrum resource. The short wave-length of mmwave signals facilitates exploiting large antenna ...arrays to achieve large array gains and combat the large path-loss. However, the use of large antenna arrays along with narrow beams leads to a large overhead in beam training for obtaining channel state information, especially in dynamic environments. To reduce the overhead of beam training, in this paper we formulate the problem of beam alignment and tracking (BA/T) as a stochastic bandit problem. In particular, to sense the change of the environments, the actions are designed based on the offset of successive beam indexes (i.e., beam index difference), which measures the rate of change of the envir-onments. Then, we propose two efficient BA/T algorithms based on the stochastic bandit learning. To reveal useful insights, the performance of effective achievable rate is further analyzed for the proposed BA/T algorithms. The analytical results show that the algorithms can sense the change of the environments and adjust beam training strategies intelligently. In addition, they do not require any priori knowledge of dynamic channel modeling, and thus are applicable to a variety of complicated scenarios. Simulation results demonstrate the effectiveness and superiority of the proposed algorithms.
Treatment strategies targeting tumor-associated macrophages (TAMs) have been proposed in cancer areas. The functional alterations of macrophages in the microenvironment during the tumorigenesis of ...human epithelial cancer remain poorly understood. Here, we explored phenotypic alteration of macrophages during the development of oral squamous cell carcinoma (OSCC).
Conditioned media (CM) and exosome supernatants were harvested from normal oral epithelium, oral leukoplakia cells and OSCC cells. We measured phenotypic alteration of macrophages using flow cytometry, luminex assays, and quantitative real-time PCR assay. Intracellular signaling pathway analysis, mass spectrometry proteomics, western blotting, enzyme-linked immunosorbent assay, immunohistochemical staining, and bioinformatics analysis were performed to uncover the underlying mechanisms.
THP-1-derived and PBMCs derived macrophages exhibited an M1-like phenotype but not M2-like phenotype, when treated with CM from OSCC cells but not with the CM from normal epithelium or leukoplakia cells. Further investigations revealed that macrophages were activated by taking up exosomes released from OSCC cells through p38, Akt, and SAPK/JNK signaling at the early phase. We further provided evidences that THBS1 derived from OSCC exosomes participated in the polarization of macrophages to an M1-like phenotype. Reciprocally, CM from exosomes induced M1-like TAMs and significantly promoted migration of OSCC cells.
We proposed a novel paracrine loop between cancer cells and macrophages based on exosomes from OSCC. Therefore, target management of M1-like TAMs polarized by exosomes shows great potential as a therapeutic target for the control of cancerous migration in OSCC.
In this paper, we shall give some properties of complex differential-difference equation of the form ∑μ=1nαμz∏i=1tfz+ciai0μf′z+ciai1μ⋯fkiz+ciaikiμ/∑ν=1mβνz∏i=1tfz+cibi0νf′z+cibi1ν⋯fkiz+cibikiν=Rz,fz, ...where aijμ μ=1,2,…,n and bijνν=1,2,…,mi=1,2,…,t;j=0,1,…,ki are non-negative integers, cii=1,2,…,t are distinct, nonzero complex numbers, αμzμ=1,2,…,n and βνzν=1,2,…,m are small functions relative to fz, and Rz,fz is a rational function in fz with coefficients, which are small functions of fz. We also consider related complex functional equations in the paper. These results are improvements of some several previous results.
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