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Nanocelluloses, their modification and application to reinforce poly(butylene adipate-co-terephthalate) bioplastic
No full textSynthetic polymers, especially those derived from polyolefins, are widely used as packaging materials. However, their non-biodegradable nature and prevailing low rate of recycling means that there is a pressing need to develop fully biodegradable packaging materials to address the environmental and sustainability concerns. The development of biodegradable packaging materials is one of the most feasible ways to address this issue. Some polymers such as thermoplastic starch (TPS), poly(lactic acid) (PLA), polyhydroxylalkanoates (PHA), polycaprolactone (PCL) and poly(butylene adipate-co-terephthalate) (PBAT) are considered as alternatives of conventional plastics. However, these polymers have certain limitations (e.g., low tensile strength, highly permeable to water vapour and oxygen and high cost) which needs further improvement. Creating composites of these polymers reinforced with suitable additives is the most pragmatic approaches to overcome their limitations. While conventional plastic composites typically use inorganic fillers such as silica, alumina and clay, biodegradable plastics benefit from biodegradable fillers such as nanocellulose and plant derived fibres. Nanocellulose-enriched polymer nanocomposites exhibit improved mechanical, thermal, barrier and functional properties. Nanocellulose is hydrophilic due to the presence of a large number of hydroxyl groups and comes with inherent incompatibility when used in non-polar (hydrophobic) plastics. The surface of nanocellulose needs to be modified, through chemical approaches, in order to make it more compatible and ascertain its homogenous distribution in the non-polar plastic matrix. When used as reinforcing materials, adequately modified nanocellulose is expected to either preserve or improve the biodegradability of the resulting composites. Evaluation of the degradation process of nanocellulose-containing polymers (i.e., composites) under industrial composting conditions gives confidence in their viability as biodegradable packaging materials.
In the above context, the first experimental chapter focused on extraction of nanocellulose from renewable jute bast fibers and determining their physicochemical characteristics. The multistep extraction process began with chemical pre-treatment to extract nanocellulose from the jute bast fibers and yielded a highly purified microfibrillated cellulose with a 56.5% yield. Cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs) were isolated through mechanical and chemical processes providing yields of 55% and 28%, respectively based on the initial dry mass of untreated jute fibers. The length of CNFs extended to micron scale with an average diameter of 14.9 nm. The CNCs were needle shaped with an average width of 10.0 nm and a length of 196.5 nm. The CNCs had much higher crystallinity (75.6%) than that of CNFs (67.5%).
In the second experimental chapter, the surface of CNCs were modified using a facile and environmentally friendly method that partially substituted the surface hydroxyl groups of CNCs with an alkoxysilane, forming a polysiloxane coating. This modification was intended to impart hydrophobic properties. The coupling of the alkoxysilane with CNCs occurred through covalent bonding and physical anchoring. Surface modification of CNCs was carried out at different triethoxyvinylsilane (TEVS) loading. Up to 17.9% of silicon (Si) concentration was observed on the surface of the modified CNC (m-CNC) at 5wt% loading of TEVS. These m-CNCs preserved their nano scale size and morphology. Homogeneous and interfacially compatible composites were prepared from poly(butylene adipate-co-terephthalate) (PBAT) reinforced with m-CNCs through solvent casting.
The research undertaken in third experimental chapter involved design of CNC containing composite plastics (PBAT as the matrix) using melt blending. Initially, the surface of CNCs was modified using vinyl silane (VS) and phenyl silane (PhS) groups. The atomic concentration of Si was found to be 12.40% in vinyl silane modified CNC (CNC-VS) and 5.41% in phenyl silane modified CNC (CNC-PhS), indicating the successful incorporation of silicon through the modification process. The findings showed that surface treatment enhanced the interfacial compatibility of CNC-PhS in PBAT matrix. The homogeneity of dispersion of these silanes modified CNCs in PBAT matrix improved the mechanical performance, barrier properties, and water repellence of the composites. Significantly lower water vapour and oxygen transmission rates were observed in these nanocomposites when compared with the pristine PBAT. The films containing 5wt% phenyl modified nanocrystals had the lowest WVTR and OTR values measuring 38.3 g m−2 day−1 and 496 cc m−2 day−1 respectively. Higher water repellence (water contact angle = 79.1°) was achieved in the films produced using phenyl silane CNCs reinforced PBAT. Compared to the modulus of neat PBAT films, PBAT/5CNCPhS showed ~58% increase in modulus and 12% increase in tensile strength through reinforcing.
The fourth experimental chapter studied the environmental fate of the PBAT-silane modified CNC composite materials and films in order to understand the extent and nature of biodegradation under industrial composting condition. The structural disintegration and mineralisation of the PBAT-CNC films were higher than that of pristine PBAT. Similarly, PBAT films reinforced with unmodified CNCs had a higher degradation rate followed by the films produced using silane modified CNCs. The rate of degradation was slowest in case of pristine PBAT. Upon 90 days, the extent of degradation was 38%, 45% and 41% for PBAT, PBAT-CNC and PBAT-CNCPhS films, respectively indicating that the reinforcing of PBAT with CNC improved PBAT’s biodegradability.
This thesis advanced the underpinning science and associated technologies towards improving the mechanical, barrier and biodegradation (composting) performance of PBAT-based bioplastics by reinforcing them with phenyl silane modified CNCs. It also contributed towards optimisation of the process of isolating CNCs from jute bast fibers and further modification of their surface using vinyl and phenyl silanes. Thus, the outcome of this thesis contributes towards mitigating the negative impact of conventional plastics. It also contributes to the sustainable use of agricultural fibers by providing an improved and easy-to-implement pathway for value adding to jute bast fibers
Understanding microstructural evolution and mechanical behaviour of AlSi10 alloy: insights from powder bed fusion laser beam and high pressure die casting processes
No full textThis investigation is focused on comprehending the impact of a broad spectrum of cooling rates ranging from 10^-2 to 10^5 K/s on the microstructure and mechanical properties of AlSi10 alloys. The AlSi10 alloys were manufactured using high pressure die casting (HPDC) and powder bed fusion-laser beam (PBF-LB) processes. A detailed comparison of microstructures was conducted to understand variations in tensile and bending properties. Subsequently, heat treatment process-property maps were formulated for the PBF-LB AlSi10Mg alloy to fine-tune the differences identified in the tensile properties of PBF-LB and HPDC alloy. These maps serve as valuable tools for advancing rapid prototyping application.
Furthermore, an in-depth microstructure analysis of both alloys facilitated the development of a kinetic Al-Si phase diagram, delineating the extent of solute trapping and eutectic temperature depression as the cooling rate increases. The higher cooling rate associated with the PBF-LB process resulted in a refined and interconnected Al-Si eutectic microstructure, contributing to back stress generation during tensile deformation. This, in turn, resulted in elevated yield strength and strain hardening coefficient. Therefore, a novel strengthening model is proposed for the PBF-LB AlSi10Mg alloy, encompassing both conventional strengthening and back stress strengthening mechanisms
Chinese herbal medicine therapies for migraine: current state of evidence, impact on practice, and a real-world setting evaluation
No full textBackground
Migraine is the second-most disabling condition worldwide and the most disabling among young females aged under 50 years. Migraine often elicits suboptimal responses and undesirable adverse events (AEs) from conventional pharmacological interventions. The concurrent presence of comorbidities and the excessive use of acute medication further compromise the limited treatment effects and result in migraine chronification. In this context, there is a critical need for alternative therapeutic options that are effective and better tolerated by patients, especially for those with complex comorbidities.
Chinese medicine is a holistic medical system that emphasises dynamic and ongoing syndrome differentiation. Chinese medicine prescriptions for migraine are tailored based on a comprehensive analysis of migraine history, severity, accompanying symptoms, comorbidities and triggers. Chinese medicine, especially Chinese herbal medicine (CHM), has been widely prescribed to over 60% of outpatient migraine patients in China. The successful experience of treating migraine related presentations using Chinese medicine has accumulated for thousands of years. In addition, several well-known and frequently used CHM prescriptions have been shown to be beneficial in clinical trials. In the framework of evidence-based practice (EBP), it is essential to comprehensively evaluate the current state of clinical evidence by integrating historical and contemporary clinical expertise, research evidence from controlled settings and real-world practice, and patients’ preferences and values from real-world practice, to support informed clinical decision-making on Chinese medicine for migraine.
Research aim, objectives and research questions
The primary research aim of this project is to establish a comprehensive and coherent integration of clinical expertise, research evidence and patients’ preferences and values to further support the EBP of CHM for migraine.
The specific objectives of this project are:
1) To establish robust research evidence on the effectiveness and safety of CHM for migraine in both controlled research settings and real-world clinical practice
2) To summarise clinicians’ expertise from classical Chinese medicine literature and real-world contemporary medical records
3) To collect patients’ preferences and values in seeking CHM for migraine from retrospective analyses of medical records and a prospective registry-based cohort study
The research questions proposed for this project to accomplish these aim and objectives are:
1) How has migraine been managed with Chinese medicine in ancient and contemporary clinical practice?
2) Is CHM effective and safe in alleviating migraine symptoms and managing comorbidities in controlled research settings and real-world clinical practice?
3) What are the preferences and concerns of migraine patients when seeking Chinese medicine for migraine?
Methods and results
The project has been designed in accordance with the three components of EBP, encompassing a data-mining study of classical literature, two systematic reviews based on randomised controlled trials (RCTs), a retrospective analysis of medical records and a prospective observational study.
1) Data-mining of classical Chinese medicine literature
This study employed well established and validated methodologies developed by the China-Australia International Research Centre for Chinese Medicine including using the Encyclopedia of Traditional Chinese Medicine 5.0. The citations were scored using modified criteria based on the diagnostic criteria for migraine without aura, which ensured their relevance to migraine. Oral CHM was the most recorded therapy, compared to intranasal and topical applications of CHM and to acupuncture. Frequency analyses revealed that chuan xiong was the most frequently orally administered herb and Chuan xiong cha tiao san (CXCTS) was the most frequently used oral formula for migraine. Association rules indicated that symptoms of vomiting and nausea were associated with the herbs sheng jiang and ban xia. Results of oral CHM for migraine in classical literature have been published in a journal article entitled ‘Natural products for migraine: Data-mining analyses of Chinese medicine classical literature’.
2) Evaluation of clinical evidence by systematic reviews
The project also undertook two systematic reviews to update the latest clinical research evidence on oral CHM for migraine in controlled settings, following the Cochrane Handbook 5.1.0. Nine major English databases were searched to identify the relevant RCTs. Meta-analyses were conducted using R 4.0.5, Review Manager 5.3 and Stata 12.0 software, and certainty of evidence was determined using Grading of Recommendations, Assessment, Development and Evaluation (GRADE). The first systematic review compared the effectiveness and safety of oral CHM to flunarizine and found that CHM was at least equivalent in effectiveness and safety to flunarizine for migraine prophylaxis, and identified chuan xiong to be the most frequently used herb from the included RCTs. The second systematic review evaluated the efficacy of CHM to placebo and confirmed that CHM was efficacious and safe for migraine, and that the treatment effects expanded as treatment duration extended from 4 weeks to 12 weeks. Both systematic reviews have been published.
3) Retrospective analysis of medical records
This study retrospectively analysed migraine-related medical records from the Guangdong Provincial Hospital of Chinese Medicine (GPHCM), finding that the herb chuan xiong and the formula CXCTS were consistently used since ancient times. Other herbs such as fu ling, gan cao, bai zhu, etc. were also frequently used in clinical practice. In contrast, non-orally administered CHM were rarely used in contemporary clinical practice. Patented Chinese herbal medicine products (PCHMPs) emerged as convenient treatments for migraine and the most frequently used one was Tong tian oral solution. The analyses also revealed a low level of treatment adherence in real-world clinical practice. Results of this study have been published in a journal paper entitled ‘Chinese herbal medicine for migraine management: A hospital-based retrospective analysis of electronic medical records’.
4) Prospective cohort study in real-world clinical practice
This study prospectively registered migraine patients to observe clinical practice of CHM for migraine, evaluate real-world outcomes of CHM for migraine and survey patients’ preferences and values. The outcomes highlighted that CHM’s effectiveness in reducing migraine severity and comorbid anxiety while enhancing patients’ quality of life, at a minimum treatment duration of 28 days. Patients expected CHM to be effective for migraine severity and managing comorbidities, but only a few patients expected to reduce their use of acute medications. Patients were primarily concerned about the potential side effects of CHM. Adherence and persistence with treatment were inadequate. The herb chuan xiong was consistently prescribed in clinical practice. Various PCHMPs were prescribed to alleviate migraine symptoms and associated comorbidities. Protocol of this study has been published in journal paper titled ‘Migraine patients visiting Chinese medicine hospital: Protocol for a prospective, registry-based, real-world observational cohort study’.
Conclusion
This project has synthesised a comprehensive evidence map incorporating clinical expertise, classical and modern research evidence and patients’ preferences, feedback and values. Patients’ expectations primarily centred on alleviating migraine severity and comorbidities, while their apprehensions revolved around potential side effects. Oral CHM was found to be effective for migraine in reducing severity and acute medication usage, as well as improving quality of life, with few AEs. The effects could be achieved at a minimum treatment duration of 28 days and enhanced with prolonged treatment. The herb chuan xiong stood as a prevalent prescription choice as the key ingredient, often in combination with other herbs selected based on CHM theory. PCHMPs can be prescribed as a more convenient and increasingly prevalent option for the purpose of managing migraine episodes and their associated symptoms and comorbidities
Developing visible light active Z-scheme WO3 / In2O3 photocatalysts for carbon dioxide reduction
No full textThis study focuses on the possibility of utilizing In2O3 and WO3 as a composite heterogeneous photocatalyst for CO2 reduction. The research aimed to enhance the visible light absorption properties of the composite photocatalyst by studying the effects of synthesis temperature, reaction time, and the order of the synthesis procedure on the characteristic properties. Finally, to evaluate the photocatalytic activity of the WO3/In2O3 composite samples for CO2 reduction.
The composite catalysts were synthesized using hydrothermal/solvothermal methods. The hydrothermal/solvothermal reaction temperature and time were varied from 180°C to 190°C and 24 hours to 48 hours, respectively. In addition, the importance of the order of the synthesis procedure of the composite catalysts were also studied. The prepared catalysts were characterized by using scanning electron microscopy (SEM) in conjunction with energy- dispersive x-ray spectrometry (EDX), x-ray diffraction (XRD) and diffuse reflection measurements (DRS).
According to the XRD results, under the studied conditions, prepared pristine In2O3 and WO3 samples depicted no significant effects from variations in hydrothermal/solvothermal temperature and synthesis time. However, during the preparation of the composite samples, these crystal structures were affected due to the order of the synthesis procedure and resulted with different tungsten oxide and indium oxide incorporated complex composite crystal phases. The In2O3/WO3 composite samples exhibited peaks relevant to cubic In2O3, hexagonal In2O3, and monoclinic NaIn(WO4)2 phases. And the WO3/In2O3 composite samples reported diffraction peaks for monoclinic WO3, cubic In2O3 and orthorhombic-In2(WO4)3.
On the other hand, in the In2O3/WO3 composite samples, extended synthesis time resulted in a slight increase in NaIn(WO4)2 peak intensities and increased synthesis temperature had no effect on the crystal structures. And in the WO3/In2O3 composite samples, at 180oC, extended synthesis time resulted in disappearance of the monoclinic WO3 phase from the composite sample, and increased synthesis temperature led to the disappearance of some of the In2(WO4)3 peaks. And extended synthesis time at 190oC, increased the monoclinic WO3 peak intensities. These results suggested that hydrothermal/solvothermal synthesis temperature and time affected crystal phases in the WO3/In2O3 samples.
XRD results further revealed that the pristine In2O3, pristine WO3 and In2O3/WO3 composite samples presented high crystallinity in the samples, while WO3/In2O3 samples showed a reduced crystallinity. Additionally, sodium contamination was observed in pristine WO3 and In2O3/WO3 composite samples.
SEM-EDX analysis showed morphologies of planar plates and nanoparticles for the as- prepared pure WO3 and In2O3, respectively. And the morphology of the pristine WO3 was affected by the changes in the synthesis temperature and time. Surprisingly, the morphology of pristine In2O3 nanostructures remained unaffected under the studied conditions. Compared to the pristine samples, distinct morphologies were reported in the composite samples, and they were affected by the order of the synthesis route. In the WO3/In2O3 composites, a morphology of nanoparticle deposition on planar plates could be observed, except in the WO3/In2O3–180- 48 sample. The WO3/In2O3–180–48 sample exhibited a homogeneous dispersion of uniform rectangular nanoflakes. Conversely, in the In2O3/WO3 samples, the morphology transformed into a mixture of nanoparticles and plates.
Furthermore, varying the synthesis temperature and time resulted in different morphologies in the WO3/In2O3 samples, and with increased temperature agglomeration was induced in the sample. Conversely, the In2O3/WO3 samples remained unaffected during the changes in synthesis temperature and time, except for In2O3/WO3–190–24 sample. Additionally, EDX results revealed that considerable sodium contamination could be observed in pristine WO3 and In2O3/WO3 composite samples.
DRS results revealed that the band gap energies and the absorption edges of the prepared WO3 and In2O3 were reported to be about 2.68 eV and 3.28 eV, and 465 nm and at 390 nm, respectively. Furthermore, all the composite samples showed narrowed bandgap energies compared to the pristine In2O3. Compared to pristine In2O3, all the WO3/In2O3 samples exhibited increased absorption in both UV and visible regions, while the In2O3/WO3 samples exhibited a red-shifted absorption only in the wavelength region of 300 nm to 390 nm, implying that the order of the synthesis route had a affected the optical properties, and the synthesis order of WO3/In2O3 seemed to provide a more favorable structure for visible light absorption. Moreover, in the WO3/In2O3 samples, when the hydrothermal preparation time was increased, improved optical properties were observed, while a change in hydrothermal temperature had only a slight effect. On the other hand, changes in synthesis temperature and time had no effect on the optical properties of In2O3/WO3 samples.
The transient absorption studies revealed that the In2O3 semiconductor photocatalyst material exhibited a considerable charge carrier generation around 400 nm wavelength. However, the rapid recombination of generated electrons and holes resulted in a complete recombination within 100 ns. Consequently, these results highlighted the necessity of modifying the In2O3 photocatalyst, or the inclusion of an appropriate hole scavenger to mitigate rapid recombination and enhance the photocatalytic efficiency of In2O3 for effective CO2 reduction.
The methylene blue dye degradation experimental results showed that all the composite photocatalysts actively degraded methylene blue under UV light and exhibited high photocatalytic activity compared to pristine WO3 and pristine In2O3 samples. Moreover, the WO3/In2O3 composite samples generally outperformed the In2O3/WO3 samples, except for the composites prepared at 190oC for 24 hours. Due to the reported distinct crystal structure, morphology, and absorption properties, the WO3/In2O3 -180-48 sample resulted with the highest activity for methylene blue dye degradation. Conversely, the lowest activity was reported for the In2O3/WO3-190-48 composite sample.
On the other hand, during the photocatalytic CO2 reduction experiments, in the presence of Na2SO3 hole scavenger, In2O3 sample achieved a CO2 reduction of 1.2%, while WO3 showed no capacity to reduce CO2. Moreover, the In2O3/WO3 sample displayed a modest CO2 reduction of 1.6%, and the WO3/In2O3 sample displayed a CO2 reduction of 3.5%, which was more than twice that of the In2O3/WO3 sample and almost threefold as of pristine In2O3. The above improved CO2 reductions in the composite samples confirmed the successful formation of a Z- scheme heterojunction between WO3 and In2O3 compounds.
Furthermore, in the presence of Na2SO3, the WO3/In2O3 and In2O3/WO3 photocatalysts demonstrated CO production rates of 174.6 μmol/g/h and 86.1 μmol/g/h, respectively, whereas In2O3 alone yielded only 65.4 μmol/g/h of CO. Moreover, in addition to CO, a generation of HCOOH was observed in the system at low concentrations. These results indicated that, under the photocatalytic reduction experimental conditions employed, both composite catalysts and In2O3 exhibited favorable activity in reducing CO2 into CO. From the dark experiment it was confirmed that the photocatalysts were activated solely by light irradiation and the CO2 reductions were indeed facilitated by the photocatalytic activation of the respective catalysts.
From above results confirmed that the formation of Z-scheme heterojunctions between WO3 and In2O3 in composite samples have improved the CO2 reduction ability of In2O3. Moreover, the hydrothermal/solvothermal synthesis conditions used for the WO3/In2O3 composite sample synthesis has formed a more favorable composite for CO2 reduction. Overall, the introduction of Na2SO3 as a hole scavenger and the heterojunction formation between WO3 and In2O3, exhibited a favorable activity in reducing CO2 into CO
Dual Business Models: Exploring the Integration and Separation of Premium and Non-premium Products in Developed Markets
No full textThis PhD thesis explores how firms in developed markets simultaneously implement dual business models (DBM) to accommodate premium and non-premium segments within their domestic market. The thesis is driven by the need to understand how firms manage the tensions that arise from targeting two distinct customer bases with opposing value propositions. Recent research suggests that developed-markets firms offer premium products (i.e., highly performing, feature-rich, and expensive) obtained through a premium product innovation strategy to target a premium customer segment. Non premium products are obtained through a non-premium innovation strategy (i.e., focused on cost) and target a non-premium customer segment. The research questions (RQs) aim to unveil how firms in developed countries implement their BM elements when simultaneously accommodating premium and non-premium and why specific strategies are used over others. Additionally, the researcher assessed the impact of the firm's size to capture a holistic picture of the phenomenon. This thesis study is primarily embedded within the seminal research stream of organisational ambidexterity and other secondary literature streams, including business model innovation (BMI), resource-constrained innovation (RCI), and Porter's generic competitive strategies to build a suitable theoretical framework that allowed the researcher to address the research questions. A qualitative research design with multiple case study research methods is employed. The empirical data includes semi-structured interviews with 21 management professionals supported by secondary data. The findings indicate that firms employ integration and separation approaches dependent on contingencies such as industry, scale, and the potential tension between premium and non-premium BMs. The thesis theoretically enhances the comprehension of the dual BM by providing a set of frameworks capturing much of the BM transformation by refining the BM into its nine constituent building blocks. It offers managers insights into tactics to resolve tension within the BM and allows firms to create synergies. The study underlines the potential of non-premium innovations, such as Frugal Innovation, to grow into greater visibility in developed economies, providing important guidance for practitioners and policymakers alike</p
The Role of Neighbourhood Social and Built Environments–Including Third Places–in Older Adults’ Social Interactions
No full textNeighbourhood environments shape older adults’ social interactions. This research conceptualises a comprehensive set of perceived and objective measures of neighbourhood social and built environments, including third places, with older adults’ social interactions. In Melbourne, based on the person-environment fit framework, mediation analyses showed that the perceived social environment measures of community spirit, participation in community groups and belonging to suburb, were the strongest predictors of social interactions, followed by a few types of perceived third places. Our findings suggest that policymakers should focus on how the objective environment characteristics are interpreted as levers when planning for changes.</p
Results (Objective value)
No full textThe objective function values obtained when using Temporal Decomposition with Filtering Matheuristic (TDFM), the large MILP formulation with filtering and only the large MILP formulation are given.The experiments were conducted using the high-performance computing resources provided by the National Computational Infrastructure (NCI) in Australia. A single core with 4 GB of RAM was utilised, and the commercial Mixed-Integer Programming solver IBM CPLEX 22.1.1 was employed.</p
Current challenges in detecting complex emotions from texts
No full textTextual emotion detection is a critical area of study with significant applications in business, education, and healthcare. Despite substantial theoretical advancements over the years, there are notable gaps in the practical implementation of these methods in the aforementioned fields. The techniques currently available do not yet seem ready for real-world application. This study offers a comprehensive review of existing approaches, datasets, and models used in textual emotion detection. Its primary objective is to identify the challenges faced in both current literature and practical applications. The findings reveal that textual datasets annotated with emotional markers are scarce, making it difficult to develop robust supervised classification models for this task. There is also a pressing need for improved models that can accurately categorize a wider range of emotional states distinctly. Finally, there is a demand for techniques capable of dimensionally detecting valence, arousal, and dominance scores from emotional experiences. These challenges stem not only from the models and applications themselves but also from the readiness of current approaches and datasets in the rapidly evolving fields of machine learning and affective computing.</p
Biodegradable Zn-5Dy Alloy with Enhanced Osteo/Angio-Genic Activity and Osteointegration Effect via Regulation of SIRT4-Dependent Mitochondrial Function
No full textZinc (Zn)–dysprosium (Dy) binary alloys are promising biodegradable bone fracture fixation implants owing to their attractive biodegradability and mechanical properties. However, their clinical application is a challenge for bone fracture healing, due to the lack of Zn–Dy alloys with tailored proper bio-mechanical and osteointegration properties for bone regeneration. A Zn-5Dy alloy with high strength and ductility and a degradation rate aligned with the bone remodeling cycle is developed. Here, mechanical stability is further confirmed, proving that Zn-5Dy alloy can resist aging in the degradation process, thus meeting the mechanical requirements of fracture fixation. In vitro cellular experiments reveal that the Zn-5Dy alloy enhances osteogenesis and angiogenesis by elevating SIRT4-mediated mitochondrial function. In vivo Micro-CT, SEM-EDS, and immunohistochemistry analyses further indicate good biosafety, suitable biodegradation rate, and great osteointegration of Zn-5Dy alloy during bone healing, which also depends on the upregulation of SIRT4-mediated mitochondrial events. Overall, the study is the first to report a Zn-5Dy alloy that exerts remarkable osteointegration properties and has a strong potential to promote bone healing. Furthermore, the results highlight the importance of mitochondrial modulation and shall guide the future development of mitochondria-targeting materials in enhancing bone fracture healing.</p
Screen Usage Time and its Associations with Neurobiological Changes and Psychological Resilience
No full textExcessive screen time is linked to neurobiological changes, including altered brain structure and connectivity, particularly in regions related to high executive functioning and emotions resulting in low psychological resilience, increased stress levels overall tempering the balanced and healthy brain environment. The current research will use ABCD data to examine the links between excessive screen usage and alterations in brain activity.</p