Enhanced Toughening of the Lamellar Structure in a Black Coral by Interlocking Spines.

The black corals possess a branched, tree-like skeleton that is composed of chitin fibrils embedded within a protein matrix. This skeleton exhibits growth rings interlocked by spines. The lamellae are tightly wrapped around the spines, creating a structure akin to an onion. The indentation hardness and Young's modulus of the spines are comparable to those of the chitin rings. The compressive stress and the fracture toughness are increased by approximately 14.6% and 32.2% at higher loading rate in the dry state, but remain comparable at different loading rates in the wet state. The lamellar interfaces have a tendency to resist sliding in the dry state. As a result, the lamellae that curve around the spines are prone to fracturing one by one, just like an onion being peeled. This allows the material to absorb more fracture energy, ensuring that the spines can effectively resist the lamellar delamination.

Long-term PM2.5 exposure associated with severity of angina pectoris and related health status in patients admitted with acute coronary syndrome: Modification effect of genetic susceptibility and disease history.

Long-term particulate matter with aerodynamic diameters ≤2.5 µm (PM2.5) exposure has been associated with the occurrence of acute coronary syndrome (ACS). However, the impact of PM2.5 exposure and its components on the severity of angina pectoris and disease-related health status in patients hospitalized for ACS is understudied. To assess the association between long-term exposure to PM2.5 components and the angina pectoris severity in ACS patients, as well as the modification effects of genetic factors and disease history in north China. During 2017-2019, 6729 ACS patients were collected in Shandong Province and Beijing, with their angina pectoris severity evaluated using Seattle Angina Questionnaire (SAQ). The 0-3 years' average concentrations of PM2.5 and its five major components were assigned to each patient's residential address. Linear mixed-effects model, weighted quantile regression, and quantile g-computation were used to estimate the effects of both single and joint associations between PM2.5 components and SAQ scores. The interactive effect was estimated by polygenic risk scores and disease history. For each interquartile range increase in PM2.5, the overall SAQ score changed by -3.71% (95%CI: -4.54% to -2.88%), with score of angina stability more affected than angina frequency and other dimensions of angina pectoris severity. Sulfate and ammonium were major contributors to the effect of PM2.5 exposure. Significant modification effect was only observed for disease history, especially for the dimension of physical limitation. Among a series of pre-existing diseases, patients with a family history of coronary artery disease, previous percutaneous coronary intervention or coronary artery bypass grafting, and stroke were more susceptible to PM2.5 exposure than others. Greater exposure to PM2.5 is associated with more serious angina pectoris and worse disease-related health status in ACS patients. Public health and clinical priority should be given to cutting down key effective components and protecting highly vulnerable individuals.

Comparative studies on the anti-wear behavior of prismatic structures in different shell species.

Prismatic structure is mainly located in the outer layer of mollusk shells. However, there is limited studies on their resistance to wear and the underlying mechanisms. The Vicker's hardness and sliding anti-wear properties of prismatic structures in four species of mollusk shells were systematically investigated for comparisons in the present work. The crystalline types, organic matrix content, structural arrangement, and dimension of prisms are varied among different species. The hardness and wear properties of prismatic structures are, in the first place, determined by the crystalline type, i.e., the aragonite prismatic structures are harder and more wear-resisting than the calcite types. The primary failure mechanism in the prismatic structure during wear tests is three-body abrasion. The volume of the crushed prism particles is directly related to the thickness of organic interface and the hardness of prisms. The organic sheaths form organic films during sliding, and thus lubricate the friction interface to some extent, but higher organic content leads to a wider interface, resulting in a higher plough force at the edge of prisms. A higher plough force gives rise to a severe three-body abrasion. Long and straight prisms perpendicular to the shell surface present a higher wear resistance. Too thin prisms cannot bear the plough force. Therefore, the anti-wear properties of prismatic structures are governed by the joint action of crystalline types, organic matrix, structural arrangement and dimension of basic building blocks.

Spatial-temporal characteristics and decoupling effects of China's transportation CO2 emissions.

Both the realization of the "double carbon" goal and the low-carbon economy development requires a focus on transportation CO2 emissions. Calculating Chinese transportation CO2 emissions and exploring its principles are essential for achieving high-quality development of the transportation industry. Firstly, we use a "top-down" method to assess carbon emissions from transportation operations from 2003 to 2019. Secondly, the study decomposes the influencing factors of transportation CO2 emissions in China using the log-average weight decomposition method. Thirdly, the Tapio decoupling model is applied to study the decoupling effect of transportation CO2 emissions in each province of China. The findings suggest that China's transport carbon emissions are growing at an annual rate of roughly 16%. All GDP per capita, transportation energy intensity, and population size increase the growth of transportation CO2 emissions. Contrastly, energy use per unit of turnover and transportation intensity decrease the growth of transportation CO2 emissions. There is much variation in China's carbon emission decoupling index from year to year. Policy recommendations are proposed in response to the study of the above findings and the differences in carbon reduction potential among provinces.

Risk Prediction Models for Ischemic Cardiovascular Outcomes in Patients with Acute Coronary Syndrome.

Acute coronary syndrome (ACS) has a high incidence of adverse cardiovascular events, even after early invasive treatment. Patients may still have a poor prognosis after discharge. The keys to the long-term survival of patients with ACS include effective treatment in a timely manner and identification of those patients who are at higher risk for long-term adverse events. Therefore, several nations have now devised a range of risk assessment models to provide data for accurately formulating treatment plans for patients with various risk levels following an ACS to prevent short and long-term cardiovascular events. The purpose of this article is to review the risk scores associated with mortality and ischemic events in patients with ACS. By using the clinical risk prediction score, we can accurately and effectively judge the prognosis of patients, so as to take a more reasonable treatment.

A Decision Model for Public Economic Environment Monitoring and Management Decision Using Improved Ant Colony Algorithm.

The quality of economic development is not sufficient, despite the apparent role that public environmental monitoring and management play in the economy's rapid expansion. Therefore, enhancing the standard of economic growth is of the utmost importance. It is vital to establish innovative management techniques to support social and governmental transformation in order to raise the standard of economic development. Economic development affects public administration's fundamental duties and goals. The division of public administration distributes social resources and enhances the market's function. The fundamental problem in public economic management is how to successfully actualize rational resource allocation, advance social justice, and boost social welfare on the basis of resource scarcity and the breakdown of the market mechanism. This study greatly increases the global optimization performance of the fundamental ant colony method and provides the explicit programme and simulation stages for the new algorithm. Finally, simulation tests are conducted using the basic ant colony algorithm and the upgraded ant colony algorithm in relation to the decision-making model of public economic management. According to the simulation findings, the revised algorithm successfully addresses the traditional approach's drawbacks, including its slow convergence speed and propensity to easily enter local minima, and its optimization performance has increased by 30.23%.

Study on the Fracture Toughness of Softwood and Hardwood Estimated by Boundary Effect Model.

The tensile strength and fracture toughness of softwood and hardwood are measured by the Boundary Effect Model (BEM). The experimental results of single-edge notched three-point bending tests indicate that the BEM is an appropriate method to estimate the fracture toughness of the present fibrous and porous woods. In softwood with alternating earlywood and latewood layers, the variation in the volume percentage of different layers in a small range has no obvious influence on the mechanical properties of the materials. In contrast, the hardwood presents much higher tensile strength and fracture toughness simultaneously due to its complicated structure with crossed arrangement of the fibers and rays and big vessels diffused in the fibers. The present research findings are expected to provide a fundamental insight into the design of high-performance bionic materials with a highly fibrous and porous structure.

Distinctive Impact of Heat Treatment on the Mechanical Behavior of Nacreous and Crossed-Lamellar Structures in Biological Shells: Critical Role of Organic Matrix.

As biological ceramic composites, mollusk shells exhibit an excellent strength-toughness combination that should be dependent on aragonite/organic matrix interfaces. The mechanical properties and fracture mechanisms of the nacreous structure in the Cristaria plicata (C. plicata) shell and crossed-lamellar structures in the Cymbiola nobilis (C. nobilis) shell were investigated, focusing on the critical role of the organic matrix/aragonite interface bonding that can be adjusted by heat treatments. It is found that heat treatments have a negative impact on the fracture behavior of the nacreous structure in the C. plicata shell, and both the bending and shear properties decrease with increasing heat-treatment temperature because of the loss of water and organic matrix. In contrast, for the crossed-lamellar structure in C. nobilis shell, the water loss in heat treatment slightly decreases its bending properties. When the organic matrix is melted after an appropriate heat treatment at 300°C for 15 min, its bending properties can be greatly enhanced; in this case, remarkable toughening mechanisms involving crack deflection and the fiber pull-out are exhibited, although the interfacial bonding strength reduces. Therefore, an appropriate heat treatment would bring about a positive impact on the fracture behavior of crossed-lamellar structure in the C. nobilis shell. The major research findings have provided an important inspiration that the inducement of moderately weak interfaces rather than all strong interfaces might enhance the comprehensive mechanical properties of fiber-reinforced ceramic composites.

An Ingenious Microstructure Arrangement in Deep-Sea Nautilus Shell against the Harsh Environment.

Mollusk shells generally consist of several macro-layers with different microstructures. To explore the specific role that different macro-layers play in the overall mechanical properties of shells, the microstructures, hardness distribution, and three-point bending behavior in the deep-sea Nautilus shell were investigated. It is found that the shell presents a hierarchical structure comprising three layers in thickness, that is, the outer, middle, and inner layers, which exhibit homogeneous, prismatic, and nacreous structures, respectively. Among them, the homogeneous structure in the outer layer is harder, which is beneficial for the shell to enhance resistance to wear and perforation. Furthermore, both the bending strength and fracture energy for group Up (loading from outer to inner surfaces) are far higher than those for group Down (loading from inner to outer surfaces), indicating that the inner nacreous layer is not only stronger but also tougher. Cracks tend to deflect at the interfaces in nacreous structure, and nacreous structure is thereby more resistant to breakage. Hence, the nacreous structure in the inner layer could protect the shell from breaking catastrophically in the deep sea with high pressure. In brief, the combination of a harder outside layer and a tougher inside layer provides an effective protective structure for the deep-sea shell, and the excellent environment adaptability of Nautilus shell can thus be interpreted in terms of its ingenious microstructure arrangement.

Single-side functionalized graphene as promising cathode catalysts in nonaqueous lithium-oxygen batteries.

High-performance cathode catalysts are always desirable for nonaqueous lithium-oxygen (Li-O2) batteries. Using density functional theory calculations, the structural, electronic, and magnetic properties of SSX-Gr with different C/X ratios (X = H or F) are systematically studied. Then, a detailed mechanism on the dissociation of O2 and the migration of Li on the SSX-Gr is revealed, based on which C6X and C8X are confirmed as the potential candidates as cathode catalysts. The studies on reaction pathways suggest that the four-electron pathway is the more possible catalytic pathway for the selected SSX-Gr. The free energy diagrams for discharging and charging processes catalyzed by SSX-Gr reveal that C6F exhibits the highest application potential due to its considerably low oxygen reduction overpotential (0.83 V) and oxygen evolution overpotential (1.47 V). The extra spins induced by single-side functionalization endow graphene with the electrocatalytic activity.

Vildagliptin Versus α-Glucosidase Inhibitor as Add-On to Metformin for Type 2 Diabetes: Subgroup Analysis of the China Prospective Diabetes Study.

INTRODUCTION: The effect of dipeptidyl peptidase-4 (DDP-4) inhibitors versus α-glucosidase inhibitors (AGIs) on the treatment of type 2 diabetes mellitus (T2DM) in a real-world setting is unknown. The aim of this real-world study was to compare the glucose-lowering effect and tolerability of vildagliptin as add-on to metformin monotherapy (VM) and AGI as add-on to metformin monotherapy (AM) in Chinese patients with T2DM. METHODS: This was a subgroup analysis of the China Prospective Diabetes Study, a post-marketing, prospective, observational, real-world study conducted at 52 centers in China. T2DM patients with inadequate glycemic control on metformin monotherapy who received VM or AM were included. The composite primary endpoint was glycemic control (hemoglobin A1c [HbA1c] < 7%) after 12 months in the absence of tolerability events (hypoglycemia, weight gain ≥ 3%, or gastrointestinal events leading to treatment discontinuation). Propensity score matching (PSM) was used to balance the two groups. RESULTS: The success rates of the composite endpoint were higher in the VM group (n = 604/159 before/after PSM) than in the AM group (n = 159/157 before/after PSM), but the difference was not statistically significant (before PSM: 53.0 vs. 46.5%, P = 0.148; after PSM: 56.7 vs. 45.9%, P = 0.055). The glycemic control rate and HbA1c reduction were similar between groups at 3, 6, and 12 months. Compared with the AM group, the VM group had lower risks of any tolerability event (relative risk [RR] 0.53, 95% confidence interval [CI] 0.33-0.83, P = 0.006), of any adverse event (AE) (RR 0.64, 95% CI 0.41-1.00, P = 0.049), and of any serious AE (RR 0.45, 95% CI 0.25-0.81, P = 0.007). CONCLUSION: The results of this real-world study suggest that vildagliptin as add-on to metformin monotherapy had a similar glucose-lowering effect to AGI as add-on to metformin monotherapy, but with better safety.

Furanocoumarin A: A Novel Anticancer Agent on Human Lung Cancer A549 Cells from Fructus liquidambaris.

BACKGROUND AND OBJECTIVE: The fruit of Fructus liquidambaris, which is recently being used for cancer treatment, has a history to be used as a traditional medicine in China for thousands of years. MATERIALS AND METHODS: Ten kg of dried F. liquidambaris was obtained with 70% alcohol-water solution under reflux for three times. The condensed extract was obtained from petroleum ether, ethyl acetate and N-butyl alcohol, respectively. Ethyl acetate extract was subjected to silica gel column, Sephadex LH-20, ODS column chromatography and RP-HPLC column chromatography to yield a new compound (1). The structure was identified through intensive analysis of NMR and MS spectra. The antitumor mechanism of the furanocoumarin A on human lung cancer A549 cells was confirmed by detecting the apoptosis-related proteins. RESULTS: Furanocoumarin A (1), a novel furanocoumarin constituent was isolated and identified from F. Liquidambaris. The IC50 value of furanocoumarin A on A549 cell lines was 65.28±5.36µM obtained by the method of MTT. The compound could induce the apoptosis of A549 cells by inducing 21.5% early apoptosis and 32.4% late apoptosis at the concentration of 60µmol/L. Western blot analysis indicated that protein expressions of p53, caspase 3 and Bax increased in a dose-dependent manner between the concentrations from 40 to 80µM. The protein expression of Bcl-2 decreased the concentration of 60 and 80µM. The ratio of Bcl-2 to Bax was inversely proportional to the dose concentration. CONCLUSION: Furanocoumarin A could be a novel anticancer agent from herbal medicine.

The Anti-proliferative Activity of GnRH Through Downregulation of the Akt/ERK Pathways in Pancreatic Cancer.

Gonadotropin-releasing hormone (GnRH) has been demonstrated to exert anti-proliferative functions on various tumor cells in endometrial, ovarian, bladder, or prostate cancer as a part of the autocrine system. In addition, the expression levels of GnRH and its receptor had been identified in breast cancer or non-reproductive cancers, such as glioblastoma and pancreatic cancer. Previous studies have reported abnormal GnRH expression in several malignant tumors, suggesting that GnRH and its receptor might be essential for tumourigenesis. In the present study, we attempted to clarify the mechanisms underlying GnRH function in cell proliferation in pancreatic cancer. Our results indicated that GnRH expression might be essential for the malignancy of pancreatic cancer. We then found that GnRH overexpression can induce cell apoptosis through activating the Bcl-2/Bax pathway and autophagy might be involved in the GnRH-mediated apoptosis in Panc1 cells. Further investigation showed that the inhibition of GnRH may promote tumor invasion and migration through upregulation of MMP2 expression in pancreatic cancer cells. Moreover, our results indicated that GnRH can regulate the Akt/ERK1/2 pathways to promote cell proliferation by inhibiting cell apoptosis in Panc1 cells. Therefore, our finding exhibited that the regulation of GnRH expression may be essential for tumourigenesis in pancreatic cancer, and might be a potential target for the treatment of the patients with pancreatic cancer.

A high-performance asymmetric supercapacitor based on vanadyl phosphate/carbon nanocomposites and polypyrrole-derived carbon nanowires.

A novel asymmetric supercapacitor device in an aqueous electrolyte is fabricated using a vanadyl phosphate/carbon nanocomposite as the positive electrode and a polypyrrole-derived carbon nanowire as the negative electrode. The vanadyl phosphate/carbon nanocomposites are synthesized by a simple two-step approach in which layered VOPO4·2H2O is first intercalated by dodecylamine and then annealed at high temperature, leading to the in situ carbonization of the intercalated dodecylamine. It is found that the sample in which the incorporated carbon with a high degree of graphitization exhibits a high specific capacitance of 469 F g-1 at a current density of 1 A g-1 and excellent rate performance (retained 77% capacitance at 10 A g-1). A polypyrrole-derived carbon nanowire is synthesized by the direct carbonization of nanowire-shaped polypyrrole, revealing a rough surface of nanowire-like frameworks and good electrochemical behavior. Taking advantage of both positive and negative materials, the assembled asymmetric supercapacitor device exhibits a high energy density of 30.6 W h kg-1 at a high power density of 813 W kg-1 in a wide voltage region of 0-1.6 V, as well as a good electrochemical stability (84.3% capacitance retention after 5000 cycles). The present work can shed light on the fabrication of novel asymmetric supercapacitors with high-performance.

Cymbiola nobilis shell: Toughening mechanisms in a crossed-lamellar structure.

Natural structural materials with intricate hierarchical architectures over several length scales exhibit excellent combinations of strength and toughness. Here we report the mechanical response of a crossed-lamellar structure in Cymbiola nobilis shell via stepwise compression tests, focusing on toughening mechanisms. At the lower loads microcracking is developed in the stacked direction, and channel cracking along with uncracked-ligament bridging and aragonite fiber bridging occurs in the tiled direction. At the higher loads the main mechanisms involve cracking deflection in the bridging lamellae in the tiled direction alongside step-like cracking in the stacked direction. A distinctive crack deflection in the form of "convex" paths occurs in alternative lamellae with respect to the channel cracks in the tiled direction. Furthermore, a barb-like interlocking mechanism along with the uneven interfaces in the 1st-order aragonite lamellae is also observed. The unique arrangement of the crossed-lamellar structure provides multiple interfaces which result in a complicated stress field ahead of the crack tip, hence increasing the toughness of shell.

A novel approach for sulfur-doped hierarchically porous carbon with excellent capacitance for electrochemical energy storage.

A novel approach for hierarchically porous S-doped carbon was developed. Owing to the obviously reduced particle size and greatly enhanced meso-/macropores, electronic conductivity and surface polarity as well as the active sites available for Faradaic reactions, the resultant S-doped carbon electrode shows an excellent supercapacitor performance.

S-doped mesoporous nanocomposite of HTiNbO5 nanosheets and TiO2 nanoparticles with enhanced visible light photocatalytic activity.

The S-doped mesoporous nanocomposite (S-TNT) of HTiNbO5 nanosheets (NSs) and anatase TiO2 nanoparticles (NPs) with exposed {101} facets has been successfully synthesized by first mixing freeze-dried HTiNbO5 NSs with titanium isopropoxide and then calcination with thiourea in air. The exposed anatase {101} facets can act as a possible reservoir of the photogenerated electrons, yielding a highly reactive surface for the reduction of O2 to O2˙(-). The partial substitution of Ti(4+) by S(6+) in the lattice of TiO2 NPs leads to a charge imbalance in S-TNT and the formation of Ti-O-S bonds. As a result, the formed cationic S-TNT favours adsorption of hydroxide ions (OH(-)(ads)) and thus captures the photo-induced holes to form hydroxyl radicals (˙OH). Moreover, with the formation of Ti-O-S bonds, partial electrons can be transferred from S to O atoms and hence the electron-deficient S atoms might capture photo-induced electrons. The surface-adsorbed SO4(2-) could also act as an efficient electron trapping center to promote the separation of charge carriers. In addition, the Ti(3+) species due to the removal of oxygen atoms during calcination and the associated oxygen vacancy defects on the surface of S-TNT could act as hole and electron scavengers, respectively. Besides, the closely contacted interface is formed between HTiNbO5 NSs and anatase TiO2 NPs due to the common features of TiO6 octahedra in two components, resulting in a nanoscale heterojunction structure to speed up the separation rate of photogenerated charge carriers. The formation of a nano-heterojunction and the incorporation of Ti(3+) and S dopants give rise to the visible and near-infrared light response of S-TNT. The combined effects greatly retard the charge recombination and improve the photocatalytic activity for the degradation of rhodamine B (RhB) and phenol solution under visible light irradiation. The corresponding photocatalytic mechanism was investigated via the active species capture experiments. The present work may provide an insight into the fabrication of delicate composite photocatalysts with excellent performance.

Porous Hybrid Composites of Few-Layer MoS2 Nanosheets Embedded in a Carbon Matrix with an Excellent Supercapacitor Electrode Performance.

Porous hierarchical architectures of few-layer MoS2 nanosheets dispersed in carbon matrix are prepared by a microwave-hydrothermal method followed by annealing treatment via using glucose as C source and structure-directing agent and (NH4 )2 MoS4 as both Mo and S sources. It is found that the morphology and size of the secondary building units (SBUs), the size and layer number of MoS2 nanosheets as well as the distribution of MoS2 nanosheets in carbon matrix, can be effectively controlled by simply adjusting the molar ratio of (NH4 )2 MoS4 to glucose, leading to the materials with a low charge-transfer resistance, many electrochemical active sites and a robust structure for an outstanding energy storage performance including a high specific capacitance (589 F g(-1) at 0.5 A g(-1) ), a good rate capability (364 F g(-1) at 20 A g(-1) ), and an excellent cycling stability (retention 104% after 2000 cycles) for application in supercapacitors. The exceptional rate capability endows the electrode with a high energy density of 72.7 Wh kg(-1) and a high power density of 12.0 kW kg(-1) simultaneously. This work presents a facile and scalable approach for synthesizing novel heterostructures of MoS2 -based electrode materials with an enhanced rate capability and cyclability for potential application in supercapacitor.

Influence of embryo handling and transfer method on pig cloning efficiency.

The somatic cell nuclear transfer (SCNT) technique could be used to produce genetically superior or genetically engineered cloned pigs that have wide application in agriculture and bioscience research. However, the efficiency of porcine SCNT currently is very low. Embryo transfer (ET) is a key step for the success of SCNT. In this study, the effects of several ET-related factors, including cloned embryo culture time, recipient's ovulation status, co-transferred helper embryos and ET position, on the success rate of pig cloning were investigated. The results indicated that transfer of cloned embryos cultured for a longer time (22-24h vs. 4-6h) into pre-ovulatory sows decreased recipient's pregnancy rate and farrowing rate, and use of pre-ovulatory and post-ovulatory sows as recipients for SCNT embryos cultured for 22-24h resulted in a similar porcine SCNT efficiency. Use of insemination-produced in vivo fertilized, parthenogenetically activated and in vitro fertilized embryos as helper embryos to establish and/or maintain pregnancy of SCNT embryos recipients could not improve the success rate of porcine SCNT. Transfer of cloned embryos into double oviducts of surrogates significantly increased pregnancy rate as well as farrowing rate of recipients, and the developmental rate of transferred cloned embryos, as compared to unilateral oviduct transfer. This study provided useful information for optimization of the embryo handling and transfer protocol, which will help to improve the ability to generate cloned pigs.

Three-Point Bending Fracture Behavior of Single Oriented Crossed-Lamellar Structure in Scapharca broughtonii Shell.

The three-point bending strength and fracture behavior of single oriented crossed-lamellar structure in Scapharca broughtonii shell were investigated. The samples for bending tests were prepared with two different orientations perpendicular and parallel to the radial ribs of the shell, which corresponds to the tiled and stacked directions of the first-order lamellae, respectively. The bending strength in the tiled direction is approximately 60% higher than that in the stacked direction, primarily because the regularly staggered arrangement of the second-order lamellae in the tiled direction can effectively hinder the crack propagation, whereas the cracks can easily propagate along the interfaces between lamellae in the stacked direction.