Mechanical behaviours and mass transport properties of bone-mimicking scaffolds consisted of gyroid structures manufactured using selective laser melting

Bone scaffolds created in porous structures manufactured using selective laser melting (SLM) are widely used in tissue engineering, since the elastic moduli of the scaffolds are easily adjusted according to the moduli of the tissues, and the large surfaces the scaffolds provide are beneficial to cell growth. SLM-built gyroid structures composed of 316L stainless steel have demonstrated superior properties such as good corrosion resistance, strong biocompatibility, self-supported performance, and excellent mechanical properties. In this study, gyroid structures of different volume fraction were modelled and manufactured using SLM; the mechanical properties of the structures were then investigated under quasi-static compression loads. The elastic moduli and yield stresses of the structures were calculated from stress-strain diagrams, which were developed by conducting quasi-static compression tests. In order to estimate the discrepancies between the designed and as-produced gyroid structures, optical microscopy and micro-CT scanner were used to observe the structures’ micromorphology. Since good fluidness is conducive to the transport of nutrients, computational fluid dynamics (CFD) values were used to investigate the pressure and flow velocity of the channel of the three kinds of gyroid structures. The results show that the sizes of the as-produced structures were larger than their computer aided design (CAD) sizes, but the manufacturing errors are within a relatively stable range. The elastic moduli and yield stresses of the structures improved as their volume fractions increased. Gyroid structure can match the mechanical properties of human bone by changing the porosity of scaffold. The process of compression failure showed that 316L gyroid structures manufactured using SLM demonstrated high degrees of toughness. The results obtained from CFD simulation showed that gyroid structures have good fluidity, which has an accelerated effect on the fluid in the middle of the channel, and it is suitable for transport nutrients. Therefore, we could predict the scaffold's permeability by conducting CFD simulation to ensure an appropriate permeability before the scaffold being manufactured. SLM-built gyroid structures that composed of 316L stainless steel were suitable to be designed as bone scaffolds in terms of mechanical properties and mass-transport properties, and had significant promise

Data_Sheet_1_Are digital natives overconfident in their privacy literacy? Discrepancy between self-assessed and actual privacy literacy, and their impacts on privacy protection behavior.pdf

Privacy literacy is recognized as a crucial skill for safeguarding personal privacy online. However, self-assessed privacy literacy often diverges from actual literacy, revealing the presence of cognitive biases. The protection motivation theory (PMT) is widely used to explain privacy protection behavior, positing that whether individuals take defensive measures depends on their cognitive evaluation of threats and coping capabilities. However, the role of cognitive biases in this process has been understudied in previous research. This study focuses on Chinese digital natives and examines the differential impacts of subjective and objective privacy literacy on privacy protection behavior, as well as the role of cognitive biases in privacy decision-making. The results show that there is no significant correlation between subjective and objective privacy literacy, and a bias exists. When privacy concern is used as a mediating variable, there are significant differences in the paths through which subjective and objective privacy literacy influence privacy protection behavior. Furthermore, privacy literacy overconfidence moderates the relationship between privacy concern and privacy protection behavior. The findings confirm the influence of cognitive biases in privacy behavior decision-making and extend the PMT. This study also calls for the government to enhance privacy literacy training for digital natives to improve their privacy protection capabilities.</p

Data_Sheet_1_From depression to wellbeing: How to protect the mental health of isolated people under the “dynamic clearance” of patients with COVID-19.docx

In 2020, COVID-19 became a global pandemic. The Chinese government’s quarantine measures tend to cause anxiety, tension and depression among the quarantined people. This article constructs a differential game model of self-regulation, government guidance and social forces guidance. Then, the psychological benefits of the masses and the benefits of the whole society under the three modes are obtained, and the applicable conditions of various connection modes are compared. The research results show that: compared with social power channeling, the public under the government channeling mode can obtain more psychological benefits. However, with the increase of guidance, the difference between the psychological benefits of different ways of guidance first decreases and then tends to be stable. Under the guidance mode, the social benefits of the government decrease, and the more guidance, the smaller the social benefits. Therefore, both the government and social forces should make use of limited resources to conduct appropriate psychological counseling for the isolated population.</p

DataSheet1_Changes in Dry-Season Water Availability and Attributions in the Yellow River Basin, China.docx

Global warming will significantly change patterns of precipitation (P) and evapotranspiration (E) and thus the surface water availability (P minus E, P–E). Changes in P–E will challenge freshwater supply, food security, and sustainability of the ecosystems. Therefore, understanding the spatiotemporal change in P–E and its drivers is key for water resources management. Here, we quantified the changes in water availability during the driest month of the year and identified its drivers in the Yellow River Basin (YRB), China, during 1982–2016. Our results showed that 89.6% of the YRB showed declining dry-season water availability in 2000–2016 compared with 1982–1999, although the total dry-season water resources (defined as the proportion of the sum of monthly P–E to the P) remained nearly unchanged due to the increased P. Changes in seasonal P and E contributed to 87.0 and 99.0% declines in dry-season water availability, respectively, demonstrating the key role of E in net seasonal water fluxes. Increased air temperature (41.8%), vegetation greening (30.8%), and vapor pressure deficit (19.2%) were the main factors driving changes in E in the YRB during the study period. Our study highlighted a drier dry season in the YRB during 1982–2016 and illustrated that climate and vegetation changes played important roles in driving changes in dry-season water availability. Seasonal water fluxes must be considered in future water resources management in the YRB, especially in the context of climate warming and revegetation programs.</p

Using Magnetic Multiwalled Carbon Nanotubes as Modified QuEChERS Adsorbent for Simultaneous Determination of Multiple Mycotoxins in Grains by UPLC-MS/MS

The simultaneous detection of multiple mycotoxins is important due to the increased toxic effects of combined mycotoxins in grains. In this research, a combination of modified QuEChERS with ultrahigh-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) was used for simultaneous detection of 20 mycotoxins in grains. A series of different types of magnetic (Fe3O4) nanoparticles modified with multiwalled carbon nanotubes (Fe3O4-MWCNTs) were designed as modified QuEChERS adsorbents for facile and efficient purification and for target interferences removal in the matrices. When there is an external magnetic field, the proposed modified QuEChERS method uses a shorter pretreatment time compared with the traditional QuEChERS method, which makes it possible to conduct high-throughput analyses. To optimize the QuEChERS process, the extraction solvent and the type and amount of the Fe3O4-MWCNTs were investigated. Under optimal conditions, the method was validated and showed satisfactory linearity (r2 ≥ 0.9965), good recovery (73.5–112.9%), good precision (1.3–12.7%), and excellent sensitivity (ranging from 0.0021 to 5.4457 ng g–1), which indicates that this method can be used for detecting multiple mycotoxins in real samples

Preparation of Carbonized MOF/MgCl₂ Hybrid Products as Dye Adsorbent and Supercapacitor: Morphology Evolution and Mg Salt Effect

Metal organic frameworks (MOFs) containing salt impurity provide a new idea for carbon material design. Presently, Mg–MOF/MgCl2 hybrid polycrystallines with different morphologies are solvothermally synthesized using 1,3,5-benzenetricarboxylic acid (BTC) or 1,4-benzenedicarboxylic acid (BDC) as the ligand, with or without polyethylene terephthalate (PET) inducer, respectively. After calcination, the products look like a flower, bud, cube, or nanosheet. When tested as adsorbent, the maximum methyl orange adsorption capacity reaches 3250 mg/g, the highest reported to date. The reason is attributed to the carbon-covered Mg salt inside the carbonized MOF. When tested as supercapacitor, carbonized MOFs based on BTC ligand show a high specific capacitance (127F/g) but a low rate capability, whereas a lower specific capacitance (121F/g) but a better rate capability (80% retention at 10A/g) are found for carbonized MOFs based on BDC. The reason is due to their different pore structures

Hematoxylin Inhibits Amyloid β‑Protein Fibrillation and Alleviates Amyloid-Induced Cytotoxicity

Accumulation and aggregation of amyloid β-protein (Aβ) play an important role in the pathogenesis of Alzheimer’s disease. There has been increased interest in finding new anti-amyloidogenic compounds to inhibit Aβ aggregation. Herein, thioflavin T fluorescent assay and transmission electron microscopy results showed that hematoxylin, a natural organic molecule extracted from <i>Caesalpinia sappan</i>, was a powerful inhibitor of Aβ42 fibrillogenesis. Circular dichroism studies revealed hematoxylin reduced the β-sheet content of Aβ42 and made it assemble into antiparallel arrangement, which induced Aβ42 to form off-pathway aggregates. As a result, hematoxylin greatly alleviated Aβ42-induced cytotoxicity. Molecular dynamics simulations revealed the detailed interactions between hematoxylin and Aβ42. Four binding sites of hematoxylin on Aβ42 hexamer were identified, including the N-terminal region, S8GY10 region, turn region, and C-terminal region. Notably, abundant hydroxyl groups made hematoxylin prefer to interact with Aβ42 via hydrogen bonds. This also contributed to the formation of π–π stacking and hydrophobic interactions. Taken together, the research proved that hematoxylin was a potential agent against Aβ fibrillogenesis and cytotoxicity

Characterization of the mitochondrial genome of <i>Chlorolobion braunii</i> ITBB-AG6, an azolla-associated green alga isolated from sanitary sewage

Sphaeropleales have the characteristics of rapid growth, high oil content, and efficient removal rates of nitrogen and phosphorus in sewage waters, and is potentially valuable in biodiesel production and environmental remediation. In this study, we isolated a strain of Sphaeropleales, Chlorolobion braunii strain ITBB-AG6 from an azolla community in a sewage pond. Its mitochondrial genome contains 110,124 bp and harbors at least 40 genes, including 15 protein-coding genes, 20 tRNA genes, and three rRNA genes. The protein-coding genes include two for ATP synthases, seven for NAD(P)H-quinone oxidoreductases (nad), three for cytochrome c oxidase subunits (coxs), and one for cytochrome b (cob). Transfer RNA genes for 18 amino acids were identified, in which the tRNA genes for leucine and serine are doubled, but the tRNA genes for threonine and valine are not annotated. Phylogenetic analysis using the mitochondrial genomes of seven families of Sphaeropleales indicated that ITBB-AG6 is closely related to Monoraphidium neglectum, and falls in the family Selenastraceae with 100% bootstrap support. Two species in the family Neochloridaceae are separated by a species in Hydrodictyaceae, indicating a polyphyletic nature. These findings revealed the complicated phylogenetic relationships of the Sphaeropleales and the necessity of genome sequences in the taxonomy of microalgae.</p

Reduction of the Bacterial Genome by Transposon-Mediated Random Deletion

Genome reduction is an important strategy in synthetic biology for constructing functional chassis cells or minimal genomes. However, the limited knowledge of complex gene functions and interactions makes genome reduction by rational design encounter a bottleneck. Here, we present an iterative and random genome reduction method for Escherichia coli, named “transposon-mediated random deletion (TMRD)”. TMRD generates random double-strand breaks (DSBs) in the genome by combining Tn5 transposition with the CRISPR/Cas9 system and allows genomic deletions of various sizes at random positions during DSB repair through the intracellular alternative end-joining mechanism. Using E. coli MG1655 as the original strain, a pool of cells with multiple random genomic deletions were obtained after five reduction cycles. The growth rates of the obtained cells were comparable to that of MG1655, while the electroporation efficiency increased by at least 2 magnitudes. TMRD can generate a small E. coli library carrying multiple and random genomic deletions while enriching the cells with environmental fitness in the population. TMRD has the potential to be widely applied in the construction of minimal genomes or chassis cells for metabolic engineering

Enhanced Performance of Metal- and Additive-Free Pyridinium-Based Photocatalysts for Selective Aerobic Oxidation: The Role of Anion Exchange in Boosting Reactive Oxygen Species Generation

Developing economically and environmentally sustainable protocols for highly effective and selective oxidation of organics is of crucial importance in both academia and industry. Aiming at activating molecular oxygen to form reactive oxygen species as the key oxidant, a series of pyridinium-based small molecules have been designed and developed as simple and effective photocatalysts for the aerobic oxidation of alcohols to aldehydes. A facile anion exchange strategy is applied to introduce heavy atoms, which promote the generation of singlet oxygen and reduce the competitive effect between electron donors. A remarkably improved photocatalytic selectivity is realized in a simple, effective, and green approach at room temperature in an air atmosphere without any metals or additives. In the face of increasingly serious energy and environmental issues, this work provides new insights into molecular oxygen activation and reveals the great potential of the pyridinium family as a green and sustainable catalyst system toward an advanced oxidation reaction and the utilization of light energy