Search

Since the 1970s, mankind has become increasingly sensitive to major world environmental protection issues, and the globalenvironmental protection laws and regulations system formed to deal with suchspecific issues has rapidly expanded in scope and depth. From the initial environmental issues in the study of international relations theory to the development of environmental issues in the study of global governance, and then the concept of global environmental governance came out and developed rapidly. This trend provides a desire to deal with many environmental protection issues and various issues related to worldenvironmental protection issues. But are these wishes real? We must also doubtthe rationality of the legal systems of various countries that have been formedand fought to deal with all environmental protection relations, especially theworld environmental protection issues. Today, the world environmental problemhas formed a relatively perfect academic field. The concept theory of globalproblems starting from ecological problems has moved from ecological problemsto world governance problems. With the introduction and rapid improvement ofthe concept of world ecological problems. The articlestarts from the role of non-state actors in the original internationalframework, further expands and deepens, and presents a multiangle andall-round perspective, showing that international law can still play a crucial role in the settlement of international environmental problems. It not only caters to the needs of the current international situation and development but also provides forward-looking guidance for future environmental governance at the global level. [ABSTRACT FROM AUTHOR]

Ti 2 AlNb alloys are expected to have applications in the aerospace field because of their excellent high-temperature performance and moderate density. Multi-wire arc-directed energy deposition (MWA-DED) technology enables the in-situ formation of Ti 2 AlNb alloys. However, Ti 2 AlNb alloys fabricated by MWA-DED face challenges such as compositional segregation and poor mechanical properties. In this study, high-performance Ti 2 AlNb alloys were efficiently prepared using MWA-DED technology, and their microstructure evolution was systematically analyzed. Hot-wire technology was proposed to assist in melting the TiNb wire to minimize the difference in the physical properties of the two wires. A pre-alloy droplet transfer mode with a large arc length was developed to eliminate composition segregation. The results showed that the Ti 2 AlNb alloys exhibited a homogeneous composition that matched the target Ti-22Al-23 Nb. Lots of strengthening phases (O phases higher than 90%) were precipitated throughout the sample. Temperature fields calculated from finite element simulation revealed that the precipitated phases were attributed to the "in-situ" heat treatment during deposition. The ultimate tensile strength and elongation reached 1002 MPa and 8% at room temperature, and 756 MPa and 8.3% at high temperature (650 ℃), respectively. The outstanding mechanical properties of Ti 2 AlNb alloys fabricated by MWA-DED are superior to those of cast and previously reported additively manufactured alloys. This study proposes novel ideas for additive manufacturing of high-performance Ti 2 AlNb alloys. [Display omitted] • Ti 2 AlNb alloys were efficiently in-situ manufactured by the multi-wire arc-directed energy deposition technique. • Hot-wire technology was proposed to eliminate the difference in physical properties of the two wires. • A pre-alloy droplet transfer model with high arc-length was explored to overcome compositional segregation. • Numerical simulations of heat transfer were developed to reveal the microstructure evolution mechanism. • High-performance Ti 2 AlNb alloys were obtained and the strengthening mechanisms were revealed. [ABSTRACT FROM AUTHOR]

The twin-wire arc additive manufacturing (TWAAM) technology is an effective method for the in-situ fabrication of Ti 2 AlNb-based alloys relative to conventional cast and wrought routes. However, composition segregation is still challenging in the field of in-situ TWAAM. To homogenize the chemical composition, here we proposed a novel single droplet pre-alloying transfer mode of TWAAM based on the original droplet transfer mode of double wires directly fed into the molten pool. The designed nominal composition of Ti-25Al-23Nb was set as the target alloy. The as-printed parts were investigated systematically. The results showed that this unique droplet transfer mode could not only improve the forming accuracy but also effectively mitigate the composition segregation. In addition, the inconsistency of microstructure caused by the composition segregation was successfully solved by this mode and appears a fully lamellar microstructure. The improvement of composition uniformity played a positive role in enhancing the mechanical properties of the alloy, in which the tensile strength of room and high temperature were improved by 76.8% and 74.1% respectively compared with our previous research. This work is of great significance to alleviate the composition segregation of intermetallics and further promote the in-situ TWAAM fabrication of Ti 2 AlNb-based alloys. • The composition segregation that challenges the Ti 2 AlNb-based alloy in-situ fabricated by twin-wire arc additive manufacturing (TWAAM) was successfully mitigated by a novel single droplet pre-alloying transfer mode. • This single droplet pre-alloying transfer mode also promotes the forming stability and accuracy during the TWAAM process. • The improvement of composition uniformity played a positive role in solving the inconsistency of microstructure and enhancing the mechanical properties. [ABSTRACT FROM AUTHOR]

To better apply the biocontrol agent Trichoderma spp. in Northeast China, collecting and screening more suitable native Trichoderma strains is necessary. In the present study, 10 isolates were obtained from Juglans mandshurica rhizosphere soils in Heilongjiang Province, and were identified as T. asperellum (four isolates), T. harzianum (four), T. hamatum (one), T. atroviride (one). The fastest-growing isolate per species on potato dextrose agar medium were further evaluated in stress tolerance tests (salt, alkali, nutritional stress, and low temperature) and confrontation assays (eight pathogens), which showed that T. asperellum TaspHu1 possessed the best adaptation and biological control ability. Then, Solanum lycopersicum (tomato) seeds were sown and treated with a series of concentrations of TaspHu1 spore suspension, as was unsown soil. Tomato seedlings treated by TaspHu1 had a significantly greater height, stem diameter, soluble protein content and soluble sugar content. Furthermore, their nitrate reductase activity and catalase activity were significantly increased, and these promoting effects depended on the concentration of the spore suspension. Meanwhile, a decrease in chlorophyll content was observed in the tomato seedlings treated with TaspHu1. In addition, strain TaspHu1 enhanced the tomato seedlings' absorption of available nitrogen, but did not influence the soil available nitrogen content. Furthermore, the resistance of tomato seedlings against Alternaria alternata was enhanced by TaspHu1 (smaller, fewer leaf spots), the seedlings' hormone signal transduction genes JAR1 , MYC2 , NPR1, PR1 , and GH3.2 were highly expressed. Thus, TaspHu1 is a promising biocontrol candidate for use in agriculture and forestry. [ABSTRACT FROM AUTHOR]

The TabZIP15 gene encoding a 396 amino acid (aa) polypeptide in the fungus Trichoderma asperellum ACCC30536 was cloned and characterised. The protein includes a basic region motif (NR-x2-QR-x2-R) and has a pillar-like structure. The 25 basic region/leucine zipper transcription factors (TFs) identified in the T. asperellum genome were divided into YAP (14 TFs), ATF2 (5), GCN4 (2), Zip1 (2), BRLZ (1) and u1 (1) subfamilies based on conserved domains. T. asperellum was cultured in minimal media (MM) control, C-Hungry and N-Hungry medium (to simulate nutrient competition and interaction with pathogens, respectively), and differential expression analysis showed that 14 TabZIP genes (including TabZIP15) were significantly altered under both conditions; TabZIP23 responded strongly to N-Hungry media and TabZIP24 responded strongly to C-Hungry media. However, only YAP genes TabZIP15, TabZIP12 and TabZIP2 were significantly upregulated under both conditions, and expression levels of TabZIP15 were highest. T. asperellum was also cultured in the presence of five fungal pathogenic toxins, and RT-qPCR results showed that TabZIP15 was significantly upregulated in four of the five toxin stress conditions (MM + Rhizoctonia solani, MM + Fusarium oxysporum, MM + Alternaria alternata and MM + Cytospora chrysosperma). [ABSTRACT FROM AUTHOR]

Background: Hepatocellular carcinoma (HCC) is a common liver malignancy with limited treatment options. Previous studies expressed the potential synergy of sorafenib and NK cell immunotherapy as a promising approach against HCC. MRI is commonly used to assess response of HCC to therapy. However, traditional MRI-based metrics for treatment efficacy are inadequate for capturing complex changes in the tumor microenvironment, especially with immunotherapy. In this study, we investigated potent MRI radiomics analysis to non-invasively assess early responses to combined sorafenib and NK cell therapy in a HCC rat model, aiming to predict multiple treatment outcomes and optimize HCC treatment evaluations. Methods: Sprague Dawley (SD) rats underwent tumor implantation with the N1-S1 cell line. Tumor progression and treatment efficacy were assessed using MRI following NK cell immunotherapy and sorafenib administration. Radiomics features were extracted, processed, and selected from both T1w and T2w MRI images. The quantitative models were developed to predict treatment outcomes and their performances were evaluated with area under the receiver operating characteristic (AUROC) curve. Additionally, multivariable linear regression models were constructed to determine the correlation between MRI radiomics and histology, aiming for a noninvasive evaluation of tumor biomarkers. These models were evaluated using root-mean-squared-error (RMSE) and the Spearman correlation coefficient. Results: A total of 743 radiomics features were extracted from T1w and T2w MRI data separately. Subsequently, a feature selection process was conducted to identify a subset of five features for modeling. For therapeutic prediction, four classification models were developed. Support vector machine (SVM) model, utilizing combined T1w + T2w MRI data, achieved 96% accuracy and an AUROC of 1.00 in differentiating the control and treatment groups. For multi-class treatment outcome prediction, Linear regression model attained 85% accuracy and an AUC of 0.93. Histological analysis showed that combination therapy of NK cell and sorafenib had the lowest tumor cell viability and the highest NK cell activity. Correlation analyses between MRI features and histological biomarkers indicated robust relationships (r = 0.94). Conclusions: Our study underscored the significant potential of texture-based MRI imaging features in the early assessment of multiple HCC treatment outcomes. [ABSTRACT FROM AUTHOR]

Background: Acute and early HIV (AEH) infection is characterized by a high viral load and infectivity. Approximately 50% of cases of HIV-1 transmission occur during AEH. Understanding sexual behaviour trajectories would be useful for predicting changes in the risk of HIV acquisition. However, few studies have investigated sexual behaviour trajectories and their association with AEH acquisition. This study identified behaviour trajectories among men who have sex with men (MSM), determined the risk of AEH infection, and compared risk factors between different behaviour trajectories. Methods: The study was based on an ongoing prospective open cohort of voluntary HIV counselling and testing (VHCT) among MSM in Tianjin, China. From 2011 to 2019, 1974 MSM were recruited. Group-based trajectory modelling (GBTM) was used to identify behaviour trajectories by constructing a sexual risk behaviour score. Logistic regression and generalized estimating equation (GEE) were used to compare the risk of AEH infection and risk factors for different behaviour trajectories. All data analyses were performed using SAS 9.4. Results: The incidence of AEH infection was 1.76/100 person-years, with 64 AEH infections documented in 3633 person-years of follow-up. Three sexual behaviour trajectories were identified: CL (consistently low risk, 35.46%), CH (consistently high risk, 42.71%) and HTL (high to low risk, 21.83%). MSM in the HTL and CH groups had higher AEH infection rates than MSM in the CL group (6.73%, 3.08% and 1.28%, respectively), with ORs of 5.54 (2.60, 11.82) and 2.44 (1.14, 5.25), respectively. MSM aged 30–50 years old and MSM who underwent HIV testing in the last year were more likely to be in the CH group and HTL group. In addition, the HTL group was characterized by a lower likelihood of local registration and a higher likelihood of working as a MSW. Conclusion: MSM in the CH group and the HTL group had a higher risk of AEH infection. In the future, VHCT should be performed more often among younger MSM, and HIV counselling should be given the same priority as HIV testing. In addition, VHCT combined with PrEP may have a better preventive impact on MSM with a high risk of AEH infection. [ABSTRACT FROM AUTHOR]

• Ti 2 AlNb-based alloys are in-situ manufactured by DWAAM technology. • Hot-wire technology is introduced to overcome the problem of the obvious difference in physical properties between two wires. • Composition distribution and macrosegregation mechanism of the in-situ prepared alloy are revealed. • Microstructure and mechanical properties of the in-situ prepared alloy are studied. • The integration of material-preparation and parts-processing is attractive for industrial production. For the reason of high temperature strength, high oxidation resistance and low density, Ti 2 AlNb-based alloy is expected to replace nickel-based alloy in the range of working temperature 600–800 °C and become a new generation of high-temperature structural alloys in the aerospace industry. However, Ti 2 AlNb-based alloys have great high-temperature deformation resistance and high brittleness, which greatly restricts its preparation and processing using traditional technology. In this research, an innovation method named double-wire arc additive manufacturing technology was adopted to in-situ manufacture Ti-22Al-24Nb (at%) alloy, and the TiNb and pure Al wire with designed feeding speed were taken as raw materials. The deposited component was investigated systematically. Results show that the composition error between the average testing value and designed value are under 1.1%, but there are also existing local segregation of composition and microstructure. The segregation phenomenon further deteriorates its mechanical properties, which means the ultimate tensile properties and elongation under room temperature and high temperature (650 °C) are 504 ± 38.59 MPa, 0.41 ± 0.03% and 375 ± 32.60 MPa, 0.76 ± 0.05% respectively on average. At the same time, the prepared alloy exhibits fully lamellar structure and XRD results show that the basic composition phases B2, O and α 2 of the Ti 2 AlNb-based alloy successfully appeared. The in-situ manufacturing method demonstrated in this work is expected to significantly promote the wider application of AM due to its low cost advantage and high flexibility. [ABSTRACT FROM AUTHOR]

[Display omitted] • A renewable adhesive was developed from hardwood lignin biomass for joining steel substrates. • Lignin content in the compositions were varied, to alter toughness, stiffness, and surface energy. • Highest adhesive strength of 13.1 MPa was measured for an optimal composition. • This study demonstrates the viability of lignin as a valuable building block for adhesives. Adhesive bonding of metals has become increasingly relevant in recent years due to the demand for reducing weight and improving performance in structural applications such as automobiles and aerospace. We developed renewable thermoplastic adhesives from technical organosolv lignin isolated from hardwood biomass and acrylonitrile butadiene co-polymer rubber (NBR) for joining steel substrates. NBR33, NBR41 and NBR51 with acrylonitrile molar ratios of 33, 41 and 51%, respectively, were blended with lignin to form two-phase thermoplastic adhesives, and their adhesion, viscoelastic and surface properties were measured. Lignin content in the compositions were varied, ranging from 40% to 80% (w/w), to alter toughness, stiffness, and surface energy characteristics of the material. Better interaction or reactivity between the lignin and NBR phases was observed with greater nitrile content in NBR, leading to greater modulus and stiffness of the adhesive. Simultaneously, increasing the proportion of lignin reduced toughness and improved stiffness, with the highest adhesive strength of 13.1 MPa measured in a 60% lignin loading ratio with NBR51. Surface energy measurements revealed that total surface energy (sum of polar and dispersive surface energy) raised with lignin loading, suggesting that both surface energy and matrix strength play a critical role in the adhesive properties of the synthesized materials. A finite element-based cohesive zone model (CZM) was developed and implemented to study the failure strength of the adhesively bonded joint. This study demonstrates the viability of lignin as a valuable building block for adhesives, not only due to its inherent chemical structure and rigidity, but also for its surface energy characteristics. [ABSTRACT FROM AUTHOR]

This work proposes an approach to minimize surface energy deactivation of plasma-treated metal and carbon fiber-reinforced polymer (CFRP) surfaces by vacuum sealing. Plasma treatments enhance adhesive wettability on post-treated surfaces for adhesive joints, but the treated surfaces deactivate quickly in air. The surface energy of aluminum alloy AA6061 and carbon fiber-reinforced polymer-polyamide (CFRP-PA66) optimally treated by a blown air plasma instrument returns to the original surface energy within 1 h. Vacuum sealing of AA6061 and CFRP-PA66 reduced the surface energy deactivation over 7 days by at least 230 times and 970 times compared to in air. Double Cantilever Beam (DCB) tests performed on adhesively-bonded AA6061/CFRP-PA66 joints showed that the total energy release and energy dissipation before failure of plasma-treated and vacuum-sealed materials was up to 60% more than plasma-treated materials without vacuum sealing and up to 125% more than non-plasma-treated materials. • Vacuum sealing significantly slowed down the deactivation of plasma-optimized surface energy of AA6061 and CFRP-PA66. • Vacuum sealing preserved hydrogen-bonded carbonyl groups on the plasma-treated CFRP-PA66 surface. • Vacuum sealing protected over-oxidation of carbon to carbonate on AA6061 surface after the plasma treatment. • In the interface between adherend surfaces and adhesive, hydroxyl groups reacted with dicyandiamide to form amide bonds. • Vacuum sealing maintained the plasma-enhanced Mode I fracture energy of adhesively-bonded AA6061-CFRP-PA66 dissimilar joints. [ABSTRACT FROM AUTHOR]