Safety-Specific Leadership, Goal Orientation, and Near-Miss Recognition: The Cross-Level Moderating Effects of Safety Climate

Near-miss recognition is an increasingly important area of research in safety management. Drawing on the self-determination theory, we ask whether and how safety-specific transformational leadership and safety-specific active transactional leadership promote near-miss recognition. We also explore the boundary condition by focusing on the moderating role of safety climate. We analyzed time-lagged data from 370 participants, and found that safety-specific transformational leadership enhances employees’ near-miss recognition (by enhancing their learning goal orientation), and that safety-specific active transactional leadership also positively influences employees’ near-miss recognition (by stimulating their performance goal orientation). In addition, we show that safety climate strengthens the relationship between safety-specific transactional leadership and employees’ performance goal orientation, but does not affect the relationship between safety-specific transformational leadership and employees’ learning goal orientation. We discuss the implications and limitations of the research

Preparation and Strength Formation Mechanism of Calcined Oyster Shell, Red Mud, Slag, and Iron Tailing Composite Cemented Paste Backfill

The use of bulk solid-waste iron tailing (IOT), red mud (RM), and oyster shells to prepare cemented paste backfill (CPB) can effectively solve the ecological problems caused by industrial solid waste storage and improve the utilization rate of such materials. In this study, a new type of CPB was prepared by partially replacing slag with RM, with calcined oyster shell (COS) as the alkaline activator and IOT as aggregate. The central composite design (CCD) method was used to design experiments to predict the effects of the COS dosage, RM substitution rate, solid mass, and aggregate–binder ratio using 28-dUCS, slump, and the cost of CPB. In this way, a regression model was established. The quantum genetic algorithm (QGA) was used to optimize the regression model, and X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and energy dispersive spectroscopy (EDS) microscopic tests are performed on CPB samples of different ages with the optimal mix ratio. The results showed that COS is a highly active alkaline substance that provides an alkaline environment for polymerization reactions. In the alkaline medium, the hematite and goethite in RM and quartz in IOT gradually dissolved and participated in the process of polymerization. The main polymerization products of the CPB samples are calcium–silicate–hydrogel (C–S–H), calcium–aluminosilicate–hydrogel (C–A–S–H), and aluminosilicate crystals such as quartz, albite, and foshagite. These products are intertwined and filled in the internal pores of the CPB, enabling the pore contents to decrease and the interiors of the CPB samples to gradually connect into a whole. In this way, the compressive strength is increased

Advances in spheroids and organoids on a chip

Multicellular spheroids and organoids are promising in vitro 3D models in personalized medicine and drug screening. They replicate the structural and functional characteristics of human organs in vivo. Microfluidic technology and micro-nano fabrication can fulfill the high requirement of the engineering approach in the growing research interest in spheroids and organoids. In this review, spheroids and organoids are comparatively introduced. Then it is illustrated how spheroids- and organoids-on-a-chip technology facilitates their establishment, expansion, and application through spatial-temporal control, mechanical cues modeling, high-throughput analysis, co-culture, multi-tissue interactions, biosensing, and bioimaging integration. The potential opportunities and challenges in developing spheroids- and organoids-on-a-chip technology are finally outlooked.Nanyang Technological UniversityPublished versionThe authors acknowledged the financial support from the Major International (Regional) Joint Research Project of NSFC (51720105015), the Science and Technology Innovation Commission of Shenzhen (KQTD20170810110913065), the Australian Research Council Laureate Fellowship Program (D.J., FL210100180), the Nanyang Presidential Fellowship Program (G.F, 03INS001307C140)

STUDY ON THE EFFECT OF ROLLING STRENGTHENING ON THE SURFACE INTEGRITY OF 45 STEEL THREAD ROOT

The self-made thread root rolling strengthening device based on common lathe CA6140 was used to perform rolling strengthening process on 45 steel thread samples. The surface integrity parameters such as surface roughness, surface microhardness, residual stress and surface microstructure of thread root after rolling were measured by using three-dimensional topography measurement instrument, microhardness tester, X-ray residual stress detector and ultra-depth of field microscope. The effect of rolling strengthening parameters on the surface integrity of thread root was investigated by single factor test. After the 45 steel thread sample underwent the rolling strengthening process, the surface roughness Sa of the thread root is reduced from 1.71 μm to 0.874 μm; the thread root forms an obvious grain refinement layer with a depth of 120 μm; the microhardness increases from 199.3 HV to 379.5 HV, and the hardening degree N=90.4%; the residual stress of the surface layer is distributed in a spoon shape, and the residual stress reaches a peak value of-542 MPa at 105 μm from the surface, and the depth of the residual compressive stress layer can reach 700 μm. The results show that the rolling strengthening process can significantly improve the surface integrity of the thread root, and the rolling depth has the most significant effect

Influence of nanoparticle shapes on cellular uptake of paclitaxel loaded nanoparticles in 2D and 3D cancer models

Enhanced cellular uptake and efficient penetration of nanocarriers inside tumors is paramount to successful anti-cancer therapy. While many studies have shown the important role nanoparticle shape plays in cellular uptake, no detailed conclusions on the most efficient drug carrier shape have been drawn at this stage. Here, a series of fructose-based amphiphilic block copolymers poly(1-O-MAFru)-b-PMMA are synthesized via RAFT polymerization. Three different morphologies (spheres, rods and vesicles) are prepared by self-assembly under different processing conditions. The shape effects of fructose-coated nanoparticles on cellular uptake by two breast cancer cell lines (MCF-7 cells and MDA-MB-231 cells) in 2D and 3D cell culture models are investigated. The cytotoxicity of corresponding paclitaxel-loaded nanoparticles are tested as well to give a comprehensive comparison between cellular uptake and resulting therapeutic efficacy after drug encapsulation in both cell culture models. Consistent results in 2D models confirm the shape effect of nanoparticles on cellular uptake. Unexpectedly, the shape does influence significantly the cell growth inhibition in 3D multicellular spheroids due to the possible cessation of transcellular delivery of nanoparticles in the apoptotic peripheral cells, caused by faster release of drugs from un-crosslinked micelles. Our results confirm the shape effect of nanoparticles on 2D models can vary from 3D models due to parameters such as spheroid penetration that can now play a pivotal role