Metal Nanocomposites Reinforced by Ceramic Nanoarchitecture: Exploiting Extrinsic Size Effects for High Mechanical Strength.

The pursuit of harnessing superior mechanical properties achieved through the size effect on a macroscopic scale has been a prominent focus in engineering, as size-induced strengthening is enabled only in the nanoscale regime. This study presents a metal/ceramic/metal (MCM) nanocomposite reinforced by ceramic nanoarchitectures. Through proximity-field nanopatterning, the inch-scale production of nanoarchitecture films is enabled in a single fabrication step. The developed three-dimensional (3D) Ni/Al2O3/Ni nanocomposite film exhibits significantly high compressive strength, corresponding to an increase of approximately 30% compared with that calculated using the upper limits of the conventional rule of mixtures. The exceptional strength of the 3D MCM nanocomposite can be attributed to the extrinsic size effect of the ceramic nanoarchitectures. By combining size-induced strengthening of ceramics with the strengthening law for composites, a new type of strengthening model is derived and experimentally validated using the 3D MCM nanocomposite.

Demand-driven capacity building for public health nutrition research in Lao PDR.

In Laos, rates of undernutrition, especially among children under 5 years of age, remain high. In response, a large multidisciplinary team embarked on a multi-year project in Laos beginning in 2019 with the purpose of institutional strengthening around public health nutrition research. This paper summarizes the Applied Nutrition Research Capacity Building project's activities, immediate project results, and prospects for sustaining impacts into the future. Eight primary activities were undertaken, including back-office strengthening, mentored research, and curriculum review and development. Requested training and skill development in areas related to public health nutrition, anthropometry, and research methods reached more than 1000 professionals. The first edition of a Lao-English Nutrition Glossary was produced, as was the country's first National Nutrition Research Agenda, a document which sets locally-identified priorities for future research. Project success was achieved by focusing on the priorities of project partners and the Lao government, as articulated in the Lao National Nutrition Strategy and Action Plan. Project design elements that could guide similar efforts undertaken elsewhere include multi-year engagement, an emphasis on sustained peer mentorship, and the use of an extended period of pre-planning in collaboration with project stakeholders prior to the start of activities.

Reconceptualizing the Interaction of Behavior and Environment.

The concept of response strength and the process of strengthening by reinforcement are controversial in terms of their explanatory power. We clarify potential theoretical misconceptions following from a strength-based account such as essentialist thinking and circular reasoning. These problems also arise in the practice of latent variable modeling in psychometrics. To solve these conceptual problems, we discuss the Multilevel Model of Behavioral Selection (MLBS; Borgstede & Eggert, 2021) as an alternative theoretical framework. We use blocking from Pavlovian conditioning as an example to demonstrate how the MLBS framework prevents misconceptions arising from strength-based accounts and how it provides a more parsimonious and coherent explanation of the phenomenon. We illustrate the need for precisely defined and theoretically meaningful concepts and offer a reinterpretation of "strengthening by reinforcement." The reconceptualization in terms of the MLBS renders the concept of response strength superfluous. We conclude by highlighting the importance of theoretical reconsideration, putting aside difficulties that arise when attempting to validate strength by empirical means.

Evaluating the Capabilities of Generative AI Tools in Understanding Medical Papers: Qualitative Study.

BACKGROUND: Reading medical papers is a challenging and time-consuming task for doctors, especially when the papers are long and complex. A tool that can help doctors efficiently process and understand medical papers is needed. OBJECTIVE: This study aims to critically assess and compare the comprehension capabilities of large language models (LLMs) in accurately and efficiently understanding medical research papers using the STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) checklist, which provides a standardized framework for evaluating key elements of observational study. METHODS: The study is a methodological type of research. The study aims to evaluate the understanding capabilities of new generative artificial intelligence tools in medical papers. A novel benchmark pipeline processed 50 medical research papers from PubMed, comparing the answers of 6 LLMs (GPT-3.5-Turbo, GPT-4-0613, GPT-4-1106, PaLM 2, Claude v1, and Gemini Pro) to the benchmark established by expert medical professors. Fifteen questions, derived from the STROBE checklist, assessed LLMs' understanding of different sections of a research paper. RESULTS: LLMs exhibited varying performance, with GPT-3.5-Turbo achieving the highest percentage of correct answers (n=3916, 66.9%), followed by GPT-4-1106 (n=3837, 65.6%), PaLM 2 (n=3632, 62.1%), Claude v1 (n=2887, 58.3%), Gemini Pro (n=2878, 49.2%), and GPT-4-0613 (n=2580, 44.1%). Statistical analysis revealed statistically significant differences between LLMs (P<.001), with older models showing inconsistent performance compared to newer versions. LLMs showcased distinct performances for each question across different parts of a scholarly paper-with certain models like PaLM 2 and GPT-3.5 showing remarkable versatility and depth in understanding. CONCLUSIONS: This study is the first to evaluate the performance of different LLMs in understanding medical papers using the retrieval augmented generation method. The findings highlight the potential of LLMs to enhance medical research by improving efficiency and facilitating evidence-based decision-making. Further research is needed to address limitations such as the influence of question formats, potential biases, and the rapid evolution of LLM models.

Enhancing motor performance through brief skin cooling: exploring the role of enhanced sympathetic tone and muscle spindle sensitivity.

BACKGROUND: Although brief skin cooling (BSC) is widely used in sports medicine and rehabilitation for its positive effects on motor performance, the mechanism underlying this motor facilitation effect remains unclear. OBJECTIVES: To explore the hypothesis that BSC enhances muscle force generation, with cold-induced sympathetic activation leading to heightened muscle spindle sensitivity, thereby contributing to this effect. METHODS: The study involved two experiments. Experiment 1 included 14 healthy volunteers. Participants submerged their hand in ice water for 3 min. Sympathetic activity was measured via heart rate (HR), muscle force generation was assessed through plantar flexor strength during maximum voluntary contraction (MVC), and cortical contribution to force generation via the volitional wave (V-wave) with and without the cold pressor test (CPT). Experiment-2 involved 11 healthy volunteers and focused on muscle spindle sensitivity and Ia synapse efficacy, assessed using soleus T-reflex and H-reflex recordings before, during, and after CPT. RESULTS: Experiment 1 showed significant increases in HR (7.8%), MVC force (14.1%), and V-wave amplitude (93.4%) during CPT compared to pre-CPT values (p = 0.001, p = 0.03, and p = 0.001, respectively). In Experiment-2, hand skin temperature significantly decreased during CPT and remained lower than pre-CPT after 15 min (p < 0.001). While H-reflex and background EMG amplitudes remained unchanged, T-reflex amplitude (113.7%) increased significantly during CPT and returned to pre-CPT values immediately afterward (p < 0.001). A strong correlation was also observed between HR and T-reflex amplitude (r = 0.916, p = 0.001). CONCLUSION: BSC enhances muscle spindle sensitivity via the sympathetic nervous system, promoting more significant muscle force generation. The method used in this study can be safely applied in clinical practice.

Articulating the ultimate objectives of research capacity strengthening programmes: Why this is important and how we might achieve it.

'Research capacity strengthening' (RCS) is an umbrella term that can be used to describe a wide variety of activities conducted in support of diverse objectives premised upon distinct, potentially opposing, views. Despite this, the ultimate objective of RCS activities is rarely made explicit which can be problematic when diverse objectives are possible. By 'ultimate' objective we are referring to the overarching (often long-term) goal an RCS initiative is intended to contribute towards (e.g. better population health) as opposed to the more immediate 'proximate' (often short-term) objectives of any such activity (e.g. improved capacity to undertake infectious disease research). We argue a need for those funding, designing and implementing RCS initiatives to make clear statements as to the ultimate objective that they foresee their respective initiative contributing towards as well as the proposed pathway and associated assumptions that underlie their approach. Examples of distinct ultimate objectives for RCS initiatives are presented alongside fictitious examples of how they may be transparently reported from both a funder and implementor perspective. Such transparency should be routine within the scope of funding calls for RCS activities (even when such activities are only a minor component of the call), subsequent applications to those calls and any description of an applied RCS activity/ies and/or the associated outcomes thereof. The process of determining one's ultimate objective will further cause funders and actors to think through their respective initiatives more thoroughly and make informed choices and better designed RCS projects. Doing so would reduce any ambiguity associated with the use of the term 'research capacity strengthening' and would provide a stronger foundation for robust programme evaluation.

Imperfection-Enabled Strengthening of Ultra-Lightweight Lattice Materials.

Lattice materials are an emerging family of advanced engineering materials with unique advantages for lightweight applications. However, the mechanical behaviors of lattice materials at ultra-low relative densities are still not well understood, and this severely limits their lightweighting potential. Here, a high-precision micro-laser powder bed fusion technique is dveloped that enables the fabrication of metallic lattices with a relative density range much wider than existing studies. This technique allows to confirm that cubic lattices in compression undergo a yielding-to-buckling failure mode transition at low relative densities, and this transition fundamentally changes the usual strength ranking from plate > shell > truss at high relative densities to shell > plate > truss or shell > truss > plate at low relative densities. More importantly, it is shown that increasing bending energy ratio in the lattice through imperfections such as slightly-corrugated geometries can significantly enhance the stability and strength of lattice materials at ultra-low relative densities. This counterintuitive result suggests a new way for designing ultra-lightweight lattice materials at ultra-low relative densities.

Microstructure, mechanical properties and strengthening mechanism of in-situ synthesized TiC/6061 nanocomposites.

In-situ synthesized 1 wt%, 3 wt% and 5 wt%TiC/6061 nanocomposites were prepared by the reaction using Al-K2TiF6-C as starting materials. Microstructure, mechanical properties and strengthening mechanism of the nanocomposites were investigated. SEM observation illustrates the in-situ synthesized ceramic TiC particles show shape of a polygon and its average size is 60 nm. TEM results show that the interface between the Al matrix and TiC reinforcement is clear and no reaction products can be found. Grain refining can be observed in the composites, as the TiC content increased from 0 wt% to 3 wt%. However, grain coarsening appears in the 5 wt%TiC/6061 composites. As increasing the TiC content from 0 wt% to 5 wt%, the mechanical properties of the composites increase firstly and then decreases. The Vickers hardness, yield strength, tensile strength and elongation of the as-cast 3 wt%TiC/6061 composites achieve the maximum value of 80.7 HV, 135 MPa, 202 MPa and 15.3 %, respectively. Strengthening mechanisms of the TiC/6061 nanocomposites is the micromechanical strengthening mechanisms. As the TiC content increasing, CTE strengthening plays an important role.

Strengthening the planning and design of Objective Structured Clinical Examinations.

Background: Although Objective Structured Clinical Examinations (OSCEs) offer innovative, objective, and fair methods of clinical assessment, their quality is compromised by poor planning and design. Aim: This study aimed to describe the development and present evidence-based recommendations on strengthening the planning and design of OSCEs for a South African public College of Nursing. Setting: A South African public College of Nursing. Methods: Recommendations were developed based on synthesising two sets of qualitative data. Set 1 included two main themes with each of the four sub-themes related to barriers and facilitators towards quality in OSCE designs from 14 nurse educator interviews and 15 external moderator reports. Set 2 included 12 quality measures to be adopted in the quality design of OSCEs derived from an integrative literature review. The draft recommendations were reviewed by eight experts to be finalised. Results: Seven recommendations were developed for strengthening OSCEs' planning and design, related to: (1) policy framework, standard operating procedures and stakeholder code of conduct; (2) blueprinting and mapping of the OSCE content; (3) developing a bank of OSCE stations; (4) scoring rubric and standard-setting method selection; (5) examiners and standardised patients' recruitment and training; (6) venue selection; and (7) station piloting. Conclusion: The seven developed recommendations can strengthen the quality of OSCEs in the South African public College of Nursing context. Contribution: The developed recommendations can assist nurse educators in planning and designing to conduct quality OSCEs following piloting and implementation.

Microstructure and Properties of Mg-Gd-Y-Zn-Mn High-Strength Alloy Welded by Friction Stir Welding.

Mg-Gd-Y-Zn-Mn (MVWZ842) is a kind of high rare earth magnesium alloy with high strength, high toughness and multi-scale strengthening mechanisms. After heat treatment, the maximum tensile strength of MVWZ842 alloy is more than 550 MPa, and the elongation is more than 5%. Because of its great mechanical properties, MVWZ842 has broad application potential in aerospace and rail transit. However, the addition of high rare earth elements makes the deformation resistance of MVWZ842 alloy increase to some extent. This leads to the difficulty of direct plastic processing forming and large structural part shaping. Friction stir welding (FSW) is a convenient fast solid-state joining technology. When FSW is used to weld MVWZ842 alloy, small workpieces can be joined into a large one to avoid the problem that large workpieces are difficult to form. In this work, a high-quality joint of MVWZ842 alloy was achieved by FSW. The microstructure and properties of this high-strength magnesium alloy after friction stir welding were studied. There was a prominent onion ring characteristic in the nugget zone. After the base was welded, the stacking fault structure precipitated in the grain. There were a lot of broken long period stacking order (LPSO) phases on the retreating side of the nugget zone, which brought the effect of precipitation strengthening. Nano-α-Mn and the broken second phase dispersed in the matrix in the nugget zone, which made the grains refine. A relatively complete dynamic recrystallization occurred in the nugget zone, and the grains were refined. The welding coefficient of the welded joint exceeded 95%, and the hardness of the weld nugget zone was higher than that of the base. There were a series of strengthening mechanisms in the joint, mainly fine grain strengthening, second phase strengthening and solid solution strengthening.

Effects of Yipi Huayu decoction on tumor markers, immune function, and adverse reactions during chemotherapy in gastric cancer patients: a retrospective propensity score-matched study.

OBJECTIVE: To analyze the effects of Yianpi Huayu Decoction on tumor markers, immune function and adverse reactions during chemotherapy in patients with gastric cancer. METHOD: The clinical data of 154 patients with progressive gastric cancer who attended Baoji Maternal and Child Health Hospital (Daijiawan Branch) from January 2020 to March 2022 were retrospectively analyzed. The patients were divided into an observation group (61 cases) and a control group (93 cases) according to the treatment method and were matched using propensity score matching (PSM). The control group was given SOX neoadjuvant chemotherapy regimen (oxaliplatin + tiglio), and the observation group was given spleen-strengthening and blood-stasis-reducing tonics as adjuvant treatment on the basis of the treatment given to the control group. Clinical efficacy in the two groups was observed, as well as Carbohydrate Antigen 19-9 (CA19-9), Carbohydrate Antigen 72-4 (CA72-4), and Carcinoembryonic Antigen (CEA) levels, immune function (IgA, IgM, and IgG), Karnofsky Performance Scale (KPS), and occurrence of adverse reactions. RESULTS: After matching, there was no significant difference in the total clinical efficiency between the two groups (P > 0.05). After matching, there were no differences in CA19-9, CA72-4, and CEA levels between the observation group and the control group before or after treatment (P > 0.05). After matching, the IgA, IgM, and IgG levels in the observation group were significantly better than those in the control group after treatment (P < 0.05). The incidence of leukopenia (P = 0.011) and diarrhea (P = 0.011) during treatment was higher in the control group than in the observation group after matching. The KPS score of the observation group was higher than that of the control group after matching (P < 0.05). After matching, Cox regression analysis found that the treatment regimen (P < 0.001, HR = 2.527), TNM staging (P = 0.001, HR = 0.471), local recurrence (P = 0.001, HR = 2.147), and pretreatment CEA (P = 0.011, HR = 1.131) were independent prognostic factors affecting patients' 2-year survival. CONCLUSION: While the spleen-enhancing and blood-stasis-removing herbal formula combined with the SOX chemotherapy regimen did not improve therapeutic outcomes in gastric cancer patients, it did enhance immune function, reduce adverse reactions, and improve quality of life.

Exploring the sports participation, muscle-strengthening exercise and active commuting with comorbidity of depression and anxiety among Chinese children and adolescents: a cross-sectional study.

Prior research has shown that physical activity (PA) is a crucial element for preserving and enhancing health, particularly among children and adolescents, and consistent engagement in PA offers numerous advantages for sustaining typical physical and mental well-being. Purpose: Hence, the primary objective of this study was to examine the relationship between sport participation, muscle-strengthening exercise (MSE), and active commuting (AC) in the co-occurrence of depression and anxiety in Chinese children and adolescents. Method: This cross-sectional investigation occurred in various cities across the southeastern region of China between March 2021 and October 2021. A convenient sampling method was utilized. We invited children and adolescents to participate in the questionnaire survey. A total of 1,996 participants completed the questionnaires with the endorsement of their parents or guardians under the supervision of schoolteachers and headmasters. Girls comprised 47.5% of the participants, and the average age of participants was 14.8 ± 2.0 years. We conducted a logistic regression analysis, including 95% confidence intervals, to explore the association between sports participation, MSE, AC, and the co-occurrence of depression and anxiety. Results: No significant association was observed between weekday active commuting for travelling to and from school and MSE and the comorbidity of depression and anxiety in children and adolescents. A negative association was only detected for those who engaged in muscle-strengthening exercises 4 days a week (OR = 0.540, 95% CI = 0.345-0.845) compared to those who did not partake in such exercises. Conclusion: The present study has provided evidence of the connection between sports participation and the co-occurrence of depression and anxiety among Chinese children and adolescents. Sports participation is more likely to help adolescents relieve anxiety and depression than AC, MSE. In forthcoming research, it is imperative to delve deeper into strategies that enhance the impact of sports on the mental well-being of children and young individuals. Furthermore, optimizing the magnitude of this effect may be achievable by focusing on neurobiological, behavioral, and psychosocial mechanisms.

Effectiveness evaluation of different steel fibers on the shear strength of reinforced SFRC slender beams without web rebars.

Current studies have mainly focused on the effect of specific steel fibers on the shear performance of steel fiber-reinforced concrete (SFRC) slender beams. However, there has been a lack of in-depth research evaluating the effectiveness of different steel fibers through a statistically comparative analysis of experimental data from various researchers. Existing design methods do not fully account for the impact of all types of steel fibers on the shear capacity of SFRC slender beams, providing very limited guidance on selecting appropriate steel fibers. This highlights the need for research to verify the strengthening effectiveness of different steel fibers. This paper establishes databases comprising 232 shear-failed reinforced SFRC beams with four other types of steel fibers straight wire, deformed wire, deformed cut-sheet and ingot mill, based on a comprehensive review of published literature. These databases complement an existing database of 280 reinforced SFRC beams using hook-end wire steel fibers as shear reinforcement. The databases are used to evaluate the validity of several well-known existing formulas for predicting the shear capacity of beams and to determine the fiber bond factor values that reflect the diverse strengthening effects of different steel fibers. Utilizing a simi-empirical synergetic prediction model for the shear strength of reinforced SFRC slender beams with hook-end wire steel fibers, the shear resistances of test beams in databases with the other four types of steel fiber are analyzed. The primary contributors to shear capacity are identified as the uncracked shear-compression SFRC and the dowel action of longitudinal tensile steel bars. The contribution of steel fibers is linked to the shear resistance of uncracked shear-compression SFRC. From a practical design perspective, a conservative prediction formula is verified, aligning with the lower boundary of the tested shear strength obtained from the database of beams. Finally, suitable steel fibers for s enhancing the shear strength of reinforced SFRC beams without web rebars are suggested based on their effectiveness.

Exploring the West African forest island phenomenon: scientific insights gained, successes achieved and capacities strengthened.

Anthropogenic activities around local villages in mesic savanna landscapes of West Africa have resulted in soil improvement and forest establishment outside their climatic zones. Such unique 'forest islands' have been reported to provide ecosystem services including biodiversity conservation. However, the science underpinning their formations is limitedly studied. In 2015 and with funding support from the Royal Society-DFID (now FCDO), we set out to investigate the biogeochemistry of the forest islands in comparison with adjacent natural savanna and farmlands across 11 locations in Burkina Faso, Ghana and Nigeria. Our results showed that the forest islands do not differ significantly from the adjoining ecosystems in soil mineralogy implying that their formation was anthropogenically driven. We observed greater soil organic carbon and nutrient distributions in the forest islands, which also had more stable macro (>500 µm) and meso-aggregates (500-250 µm) than the adjoining agricultural lands. We found that soil micro-aggregate (250-53 µm) stability was climate (precipitation) driven in the West African ecosystems while meso- and macro-aggregate stability was land-use driven. In one of the unique forest islands we studied in the Mole National Park of Ghana, we found its mineral-associated organic carbon over 40% greater than the adjoining natural savanna with potential implications for the achievement of the global initiative of the '4p1000' in West Africa. We conclude that the North-South-South research collaboration has established clearly, the science underlying the age-long West African forest island phenomenon and has, among many successes, led to capacity building of young scientists driving cutting-edge research in climate change adaptation and food systems transformation in the sub-region.

An evaluation of a multi-partner approach to increase routine immunization coverage in six northern Nigerian States.

BACKGROUND: Global health partnerships are increasingly being used to improve coordination, strengthen health systems, and incentivize government commitment for public health programs. From 2012 to 2022, the Bill & Melinda Gates Foundation (BMGF) and Aliko Dangote Foundation (ADF) forged Memorandum of Understanding (MoU) partnership agreements with six northern state governments to strengthen routine immunization (RI) systems and sustainably increase immunization coverage. This mixed methods evaluation describes the RI MoUs contribution to improving program performance, strengthening capacity and government financial commitment as well as towards increasing immunization coverage. METHODS: Drawing from stakeholder interviews and a desk review, we describe the MoU inputs and processes and adherence to design. We assess the extent to which the program achieved its objectives as well as the benefits and challenges by drawing from a health facility assessment, client exit interview and qualitative interviews with service providers, community leaders and program participants. Finally, we assess the overall impact of the MoU by evaluating trends in immunization coverage rates. RESULTS: We found the RI MoUs across the six states to be mostly successful in strengthening health systems, improving accountability and coordination, and increasing the utilization of services and financing for RI. Across all six states, pentavalent 3 vaccine coverage increased from 2011 to 2021 and in some states, the gains were substantial. For example, in Yobe, vaccination coverage increased from 10% in 2011 to nearly 60% in 2021. However, in Sokoto, the change was minimal increasing from only 4% in 2011 to nearly 8% in 2021. However, evaluation findings indicate that issues pertaining to human resources for health, insecurity that inhibits supportive supervision and vaccine logistics as well as harmful socio-cultural norms remain a persistent challenge in the states. There is also a need for a rigorous monitoring and evaluation plan with well-defined measures collected prior to and throughout implementation. CONCLUSION: Introducing a multi-partner approach grounded in a MoU agreement provides a promising approach to addressing health system challenges that confront RI programs.

Isokinetic Knee Strengthening Impact on Physical and Functional Performance, Pain Tolerance, and Quality of Life in Overweight/Obese Women with Patellofemoral Pain Syndrome.

Background/Objectives: Patellofemoral syndrome is a common osteoarticular condition that affects many individuals. Various treatment options are available, with a significant emphasis on targeted muscle-strengthening exercises. The purpose of this study was to investigate the effect of isokinetic muscle strengthening on muscle strength, joint range of motion, quality of life, physical performance, and pain tolerance in overweight/obese women with patellofemoral syndrome. Methods: Twenty-four overweight or obese women with patellofemoral syndrome participated in the study during September and October 2023 in a private medical facility for physical medicine and functional rehabilitation. They were randomly assigned to one of two groups for six weeks of isokinetic muscle strengthening. The first group (ISO.G) followed a rehabilitation program combined with isokinetic muscle strengthening. A second group (PCM.G) followed a rehabilitation program that includes an isokinetic protocol in passive compensation movement. The extensors' peak torque was measured before and after training. Results: The flexors' peak torque, stair climbing test, 10 m walk, chair lift, monopodal support, goniometric knee flexion test, heel-buttock distance measurement, pain, and quality of life scores improved significantly in both groups. The ISO.G, on the other hand, benefited from a significant increase in quadriceps muscle strength revealed by the extensors' peak torque. Conclusions: For the treatment of patellofemoral syndrome, isokinetic muscle strengthening in concentric mode appears to have a significant advantage over the classic rehabilitation program with isokinetic passive compensation, particularly in muscle strength gain, in addition to the improvement of joint range of motion, quality of life, physical performance, and pain tolerance. Isokinetic training may be recommended as a beneficial approach for the rehabilitative treatment of patellofemoral pain syndrome in overweight/obese women.

The GIBACHT fellowship: a multilateral initiative for strengthening capacity in biosafety and biosecurity towards pandemic preparedness.

The German Biosecurity Programme was launched in 2013 with the aim to support partner countries overcome biological threats including natural outbreaks or the intentional misuse of highly pathogenic agents. As part of this programme, this paper describes the development and implementation of a multilateral biosafety and biosecurity training initiative, called 'Global Partnership Initiated Biosecurity Academia for Controlling Health Threats' (GIBACHT). To achieve its objectives, GIBACHT implemented a blended-learning approach with self-directed, distance-based learning phases and three training-of-trainer workshops. The programme follows Kirkpatrick's model of learning to guarantee sustainable effects of improved knowledge and skills. One hundred nine fellows from 26 countries have been trained in seven cohorts. Many GIBACHT alumni have established additional biosafety/biosecurity trainings in their home countries. The knowledge exchange is strengthened by the implementation of a Moodle-based alumni network. GIBACHT has the potential to contribute to strengthening the capacities of partner countries in Africa, the Middle East, and South and Central Asia to respond and build resilience to biological threats.

Research on Microstructure, Mechanical Properties, and High-Temperature Stability of Hot-Rolled Tungsten Hafnium Alloy.

W-(0, 0.1, 0.3, 0.5) wt.% Hf (mass fraction, wt.%) materials were fabricated by the powder metallurgy method and hot rolling. The microstructure, mechanical properties, and high-temperature stability of alloys with varying compositions were systematically studied. The active element Hf can react with the impurity O segregated at the grain boundary to form fine dispersed HfO2 particles, refining the grains and purifies and strengthening the grain boundary. The average size of the sub-grains in the W-0.3 wt.% Hf alloy is 4.32 µm, and the number density of the in situ-formed second phase is 6.4 × 1017 m-3. The W-0.3 wt.% Hf alloy has excellent mechanical properties in all compositions of alloys. The ultimate tensile strength (UTS) is 1048 ± 17.02 MPa at 100 °C, the ductile fracture occurs at 150 °C, and the total elongation (TE) is 5.91 ± 0.41%. The UTS of the tensile test at 500 °C is 614 ± 7.55 MPa, and the elongation is as high as 43.77 ± 1.54%. However, more Hf addition will increase the size of the second-phase particles and reduce the number density of the second-phase particles, resulting in a decrease in the mechanical properties of the tungsten alloy. The isochronal annealing test shows that the recrystallization temperature of W-Hf alloy is 1400 °C, which is 200 °C higher than rolling pure tungsten.

Study on the Aging Precipitation Behavior and Kinetics of Al-10.0Zn-3.0Mg-2.8Cu Alloy by Pre-Deformation Treatment.

In this paper, the effect of thermomechanical treatment process on the hardening behavior, grain microstructure, precipitated phase, and tensile mechanical properties of the new high-strength and high-ductility Al-10.0Zn-3.0Mg-2.8Cu alloy was studied, and the optimal thermomechanical treatment process was established. The strengthening and toughening mechanisms were revealed, which provided technical and theoretical guidance for the engineering application of this kind of high strength-ductility aluminum alloy. Al-10.0Zn-3.0Mg-2.8Cu alloy cylindrical parts with external longitudinal reinforcement were prepared by a composite extrusion deformation process (reciprocal upsetting + counter-extrusion) with a true strain up to 2.56, and the organizational evolution of the alloys during the extrusion deformation process and the influence of pre-stretching treatments on the subsequent aging precipitation behaviors and mechanical properties were investigated. The results show that firstly, the large plastic deformation promotes the fragmentation of coarse insoluble phases and the occurrence of dynamic recrystallization, which results in the elongation of the grains along the extrusion direction, and the volume fraction of recrystallization reaches 42.4%. Secondly, the kinetic study showed that the decrease in the activation energy of precipitation increased the nucleation sites, which further promoted the diffuse distribution of the second phase in the alloy and a higher number of nucleation sites, while limiting the coarsening of the precipitated phase. When the amount of pre-deformation was increased from 0% to 2%, the size of the matrix precipitated phase decreased from 5.11 µm to 4.1 µm, and when the amount of pre-deformation was increased from 2% to 7%, the coarsening of the matrix precipitated phase took place, and the size of the phase increased from 4.1 µm to 7.24 µm. The finalized heat treatment process for the deformation of the aluminum alloy tailframe was as follows: solution (475 °C/3 h) + 2% pre-stretching + aging (120 °C/24 h), at which the comprehensive performance of the alloy was optimized, with a tensile strength of 634.2 MPa, a yield strength of 571.0 MPa, and an elongation of 15.2%. The alloy was strengthened by both precipitation strengthening and dislocation strengthening. After 2% pre-stretching, the fracture surface starts to be dominated by dense tough nest structure, and most of them are small tough nests, and small and dense tough nests are the main reason for the increase in alloy toughness after 2% pre-stretching deformation.