Embryonic Porcine Skin Precursors Can Successfully Develop into Integrated Skin without Teratoma Formation Posttransplantation in Nude Mouse Model

How to improve the wound healing quality of severe burn patients is still a challenge due to lack of skin appendages and rete ridges, no matter how much progress has been made in the fields of either stem cell or tissue engineering. We thus systematically studied the growth potential and differentiation capacity of porcine embryonic skin precursors. Implantation of embryonic skin precursors (PESPs) of different gestational ages in nude mice can generate the integrity skin, including epidermis, dermis and skin appendages, such as sweat gland, hair follicle, sebaceous gland, etc.. PESPs of embryonic day 42 possess the maximal growth potential, while, the safe window time of PESPs transplantation for prevention of teratoma risk is E56 or later. In conclusion, PESPs can form the 3 dimensional structures of skin with all necessary skin appendages. Our data strongly indicate that porcine embryonic skin precursors harvested from E56 of minipig may provide new hope for high-quality healing of extensive burns and traumas

Overview of Theory and Model of Tropical Agricultural Circular Economy in Hainan Province

This paper gives a general overview of rationale of tropical agricultural circular economy. On me basis of ecological economic theory, circular economy is a new model of economic development which aims at realizing reducing of resources use, reuse of products and recycling of wastes, conforming to the principle of 4R. It is to make economic system melt into me process of cycle of material of natural ecological system harmoniously. This paper introduces the advantages of developing tropical agriculture in Hainan Province, the main problems existing in the development and mo main models of sustainable tropical agricultural development in Hainan Province at present. 9 typical models of tropical agriculture circular economy in Hainan Province are listed in particular, including compound ecological project of forestry and animal husbandry, three-dimensional planting model of plantation, multilayered structure of eucalyptuses, sustainable agriculture model of sightseeing, the model of using animal manure. precision tropical agriculture model. clean production model of tropical agriculture. deep processing model of tropical agriculture products. and the model of ecological agriculture industrialization. Corresponding countermeasures and suggestions-are put forward to promote development of tropical agriculture circular economy in Hainan Province as follows: take actions that suit local circumstances, exert advantage and exploit potential; give full play to advantage of integration of production, teaching and research, and promote agriculture by applying scientific and technological advances; the whole staff participate and strengthen construction of soft environment and hard environment

Overview of Theory and Model of Tropical Agricultural Circular Economy in Hainan Province

This paper gives a general overview of rationale of tropical agricultural circular economy. On me basis of ecological economic theory, circular economy is a new model of economic development which aims at realizing reducing of resources use, reuse of products and recycling of wastes, conforming to the principle of 4R. It is to make economic system melt into me process of cycle of material of natural ecological system harmoniously. This paper introduces the advantages of developing tropical agriculture in Hainan Province, the main problems existing in the development and mo main models of sustainable tropical agricultural development in Hainan Province at present. 9 typical models of tropical agriculture circular economy in Hainan Province are listed in particular, including compound ecological project of forestry and animal husbandry, three-dimensional planting model of plantation, multilayered structure of eucalyptuses, sustainable agriculture model of sightseeing, the model of using animal manure. precision tropical agriculture model. clean production model of tropical agriculture. deep processing model of tropical agriculture products. and the model of ecological agriculture industrialization. Corresponding countermeasures and suggestions-are put forward to promote development of tropical agriculture circular economy in Hainan Province as follows: take actions that suit local circumstances, exert advantage and exploit potential; give full play to advantage of integration of production, teaching and research, and promote agriculture by applying scientific and technological advances; the whole staff participate and strengthen construction of soft environment and hard environment.Circular economy, Tropical agriculture, Sustainable development, Hainan, China, Agribusiness,

Sorption of Atrazine in Tropical Soil by Biochar Prepared from Cassava Waste

Biochar (BC) is a carbonaceous and porous product generated from the incomplete combustion of biomass and has been recognized as an efficient adsorbent. This study evaluated the ability of BC to sorb atrazine pesticide in tropical soil, and explored potential environmental values of BC on mitigating organic micro-pollutants. BC was produced from cassava waste via pyrolyzation under oxygen-limiting conditions at 350, 550, and 750 °C (MS350, MS550, and MS750, respectively). Three biochars were characterized and investigated as sorbents for the removal atrazine from tropical soil. BC pyrolyzed at higher temperatures more quickly reached equilibrium. The pseudo-second-order model perfectly simulated the sorption kinetics for atrazine with the coefficients R2 above 0.996, and the sorption amount at equilibrium (qe) was 0.016 mg/g for MS350, 0.025 mg/g for MS550 and 0.050 mg/g for MS750. The isotherms of MS350 displayed relatively linear behavior, whereas the sorption of atrazine on MS550 and MS750 followed a nonlinear isotherm. The sorption data were well described by the Freundlich model with logKF of 0.476 for MS350, 0.771 for MS550, 1.865 for MS750. A thermodynamic study indicated that the sorption of atrazine in BC-added soil was a spontaneous and endothermic process and was primarily controlled by physisorption. In addition, lower pH was conducive to the sorption of atrazine in BC-added soil

Adsorption Characteristics of Norfloxacin by Biochar Prepared by Cassava Dreg: Kinetics, Isotherms, and Thermodynamic Analysis

Biochars (BC) generated from biomass residues have been recognized as effective sorbents for organic compounds. In this study, biochars as adsorbents for the removal of norfloxacin (NOR) from aqueous solutions were evaluated. Biochars were prepared from cassava dregs at 350 °C, 450 °C, 550 °C, 650 °C, and 750 °C, respectively (labeled as BC350, BC450, BC550, BC650, and BC750). The results showed that the kinetic data were best fitted to the pseudo second-order model, indicating that the sorption was governed by the availability of sorption sites on the biochar surfaces rather than the NOR concentration in the solution. Sorption isotherms of NOR were well described by the Freundlich model, and the Freundlich coefficients (lgkF) increased with the pyrolysis temperature of biochars. Thermodynamic analysis indicated the feasibility and spontaneity of the NOR adsorption process. The NOR adsorption on BC450, BC550, BC650, and BC750 was an endothermic process, while an exothermic process occurred for BC350. FTIR studies further suggested that the adsorption mechanism was possibly attributable to H-bond and π-π interactions between NOR and biochars. Overall, this work constitutes a basis for further research considering the bioavailability and toxicity of antibiotics in the presence of biochar

Study on the Effect of Cations on the Surface Energy of Nano-SiO₂ Particles for Oil/Gas Exploration and Development Based on the Density Functional Theory

Although nano SiO2 exhibits excellent application potential in the field of oil and gas exploration and development, such as drilling fluid, enhanced oil/gas recovery, etc., it is prone to agglomeration and loses its effectiveness due to the action of cations in saline environments of oil and gas reservoirs. Therefore, it is crucial to study the mechanism of the change in energy between nano SiO2 and cations for its industrial application. In this paper, the effect of cations (Na+, K+, Ca2+, and Mg2+) on the surface energy of nano SiO2 particles is investigated from the perspective of molecular motion and electronic change by density functional theory. The results are as follows: Due to the electrostatic interactions, cations can migrate towards the surface of nano SiO2 particles. During the migration process, monovalent cations are almost unaffected by water molecules, and they can be directly adsorbed on the surface by nano SiO2 particles. However, when divalent cations migrate from a distance to the surface of nano SiO2 particles, they can combine with water molecules to create an energy barrier, which can prevent them from moving forward. When divalent cations break through the energy barrier, the electronic kinetic energy between them and nano SiO2 particles changes more strongly, and the electrons carried by them are more likely to break through the edge of the atomic nucleus and undergo charge exchange with nano SiO2 particles. The change in interaction energy is more intense, which can further disrupt the configuration stability of nano SiO2. The interaction energy between cations and nano SiO2 particles mainly comes from electrostatic energy, followed by Van der Waals energy. From the degree of influence of four cations on nano SiO2 particles, the order from small to large is as follows: K+ + 2+ 2+. The research results can provide a theoretical understanding of the interaction between nano SiO2 particles and cations during the application of nano SiO2 in the field of oil and gas exploration and development

Construction of Multi-Defective ZnMn₂O₄/Carbon Nitride Three-Dimensional System for Highly Efficient Photocatalytic Sulfamethoxazole Degradation

Rational design of composite nanostructured photocatalytic systems with good sunlight absorption capacity and efficient charge separation and transfer ability is an urgent problem to be solved in photocatalysis research. Here, a ZnMn2O4 decorated three-dimensional carbon nitride with O, C co-doping, and nitrogen defect composite photocatalytic system was prepared using a simple hydrothermal method and subsequent calcination method. For the photocatalytic reactions, the presence of heterostructures, C, O co-doping, and nitrogen defects greatly promotes the separation and transfer of charges at the semiconductor/semiconductor interface under the local electric field, thereby extending its service life. The photocatalytic degradation efficiency of sulfamethoxazole in water is as high as 94.3% under the synergistic effects, which is also suitable for the complex water environment. In addition, the synthesized photocatalyst has good chemical stability and recyclability. This study provides a new opportunity to solve the problem of environmental pollution

Enhancing the robustness of recommender systems against spammers.

The accuracy and diversity of recommendation algorithms have always been the research hotspot of recommender systems. A good recommender system should not only have high accuracy and diversity, but also have adequate robustness against spammer attacks. However, the issue of recommendation robustness has received relatively little attention in the literature. In this paper, we systematically study the influences of different spammer behaviors on the recommendation results in various recommendation algorithms. We further propose an improved algorithm by incorporating the inner-similarity of user's purchased items in the classic KNN approach. The new algorithm effectively enhances the robustness against spammer attacks and thus outperforms traditional algorithms in recommendation accuracy and diversity when spammers exist in the online commercial systems