Hasil untuk "General. Including alchemy"

Rui Feng, Xuguang Chen, Yue Wu et al.

Photodynamic antibacterial therapy presents a promising strategy for combating bacterial infections due to its non-invasive nature and low potential for inducing resistance. In this work, we developed a series of electron beam-modified graphitic carbon nitride (g-C₃N₄, CN) and titanium carbide (Ti₃C₂, TC) nanocomposites, which were subsequently incorporated into polyvinyl alcohol/sodium alginate (PVA/SA) hydrogels through physical cross-linking. The optimized 200CN/1TC composite hydrogel (where 200CN denotes 200 kGy irradiation dose, and 1TC represents 1 wt% TC content) maintained excellent biocompatibility with cell viability exceeding 80% even at the highest nanomaterial loading (8% 200CN/1TC). Notably, the 8% 200CN/1TC composite hydrogel displayed substantial antibacterial activity, forming inhibition zones of 12.3 mm and 10.8 mm against <i>Staphylococcus aureus</i> and <i>Escherichia coli</i>, respectively. The improved performance may be explained by the combined effects of enhanced electron transfer between the component materials and the unique two-dimensional structure of the nanocomposites, though further investigation is required to fully elucidate the underlying mechanisms. This study provides a feasible approach for developing efficient antibacterial hydrogel systems and offers valuable perspectives on the design of nanomaterial-based biomedical materials for wound healing and infection control applications.

Xinghan He, Yongyi Wei, Ke Xu

Diabetic wounds are characterized by a refractory healing cycle resulting from the synergistic effects of hyperglycemic microenvironment, oxidative stress, bacterial infection, and impaired angiogenesis. Conventional hydrogel dressings, with limited functionality, struggle to address the complexities of chronic diabetic ulcers. Smart hydrogels, possessing biocompatibility, porous architectures mimicking extracellular matrix, and environmental responsiveness, have emerged as promising biomaterials for diabetic wound management. This review systematically elucidates the specific response mechanisms of smart hydrogels to wound microenvironmental stimuli, including pH, matrix metalloproteinase-9 (MMP-9), reactive oxygen species (ROS), and glucose levels, enabling on-demand release of antimicrobial agents and growth factors through dynamic bond modulation or structural transformations. Subsequently, the review highlights recent advances in novel hydrogel-based sensors fabricated via optical (photonic crystal, fluorescence) and electrochemical principles for real-time monitoring of glucose levels and wound pH. Finally, critical challenges in material development and scalable manufacturing of multifunctional hydrogel components are discussed, alongside prospects for precision diagnostics and therapeutics in diabetic wound care.

Anna Borisovna Karabanova, Sergey Olegovich Ilyin, Anna Vladimirovna Vlasova et al.

Despite extensive use of polyvinylpyrrolidone (PVP)–polyethylene glycol (PEG) hydrogels in biomedical adhesives, a systematic understanding of how water content governs their rheological and adhesive performance remains lacking—particularly under variable humidity. This work addresses this gap by introducing 3–12 wt% hydroxypropyl cellulose (HPC) as a non-covalent crosslinker into a PVP/PEG gel (2/1 wt/wt) to tune its moisture uptake and stabilize viscoelasticity, thereby enabling robust, humidity-adaptive adhesion. Analysis of water content in hydrogels across a relative humidity range of 3% to 100% revealed that HPC restricts their water absorption capacity, thereby enhancing their tolerance to high-humidity conditions. The adhesive and rheological properties of the hydrogels were investigated as functions of HPC and water concentrations. With an increase in the HPC content, the adhesive properties of the initial low-water hydrogels decreased. However, high humidity strongly affected the hydrogels’ adhesive and rheological properties. The water content for hydrogels to maintain their adhesive properties was about 7–16%, depending on the hydrogel composition. This range corresponds to relative air humidity of 45–80%, tending to shift towards more moisture conditions under the effect of HPC. Thus, HPC enables PVP/PEG adhesives to operate over a broader range of relative humidities and in contact with wet skin when used in medicine as matrices for transdermal therapeutic systems, wound dressings, and flexible electrodes.

Aleksey Maksimkin, Mikhail Zadorozhnyy, Kseniia V. Filippova et al.

The creation of quick-reacting electrically conductive polymers for use as actuators driven by low electrical currents is now seen as an important issue. Enhancing the electrical conductivity of hydrogels through the incorporation of conductive fillers, like salts, can reduce the necessary actuating voltage. However, several important questions arise about how the type of salt chosen and its concentration will affect not only the activation efficiency of the actuators but also the structure of the hydrogels utilized. In this study, to enhance the electrical conductivity of the hydrogel and lower the necessary activation voltage of the hydrogel actuators, lithium chloride (LiCl) and sodium chloride (NaCl) were incorporated as conductive fillers into the polyvinyl alcohol (PVA) polymer matrix. To determine the deformation of actuators, as well as the activation and relaxation times and efficiencies during activation, linear actuators capable of being activated through extension/contraction (swelling/shrinking) cycles were developed and examined based on the LiCl/NaCl content, applied voltage, and frequency. The main finding is that the required actuating voltage was lowered by up to 20 V by adding an equal mass of salt in relation to the PVA mass content. With a load of around 20 kPa, it was observed that the extension deformation for PVA/NaCl-based actuators can achieve 75%, while in contraction deformation, can reach 17%. Additionally, for the PVA/LiCl-based actuators, the extension deformation can reach 87%, while during contraction deformation, it can reach 22%. The degree of swelling in the PVA/NaCl hydrogels was generally less than that in the PVA/LiCl hydrogels, which was associated with the finding that the actuators prepared from PVA/NaCl hydrogels delivered an output that was 10–15% lower than those made from PVA/LiCl hydrogels across different testing cycles. Furthermore, adding salt increases the degree of crosslinking, which can explain why increased crosslinking leads to reduced deformation when exposed to AC voltage. These actuators can find extensive use in soft robotics, artificial muscles, medical applications, and aerospace industries.

Anna Florowska, Tomasz Florowski, Osvaldo H. Campanella

The strategic modification of gel systems constitutes a fundamental direction in contemporary food science, enabling the design of products with enhanced functionality, nutritional value, and consumer acceptability [...]

Amr S. Mohamed, Emily Nguyen, Deepa Kundur

Amidst the growing demand for implementing advanced control and decision-making algorithms|to enhance the reliability, resilience, and stability of power systems|arises a crucial concern regarding the safety of employing machine learning techniques. While these methods can be applied to derive more optimal control decisions, they often lack safety assurances. This paper proposes a framework based on control barrier functions to facilitate safe learning and deployment of reinforcement learning agents for power system control applications, specifically in the context of automatic generation control. We develop the safety barriers and reinforcement learning framework necessary to establish trust in reinforcement learning as a safe option for automatic generation control - as foundation for future detailed verification and application studies.

Victoria Effiong Effanga, Dana Akilbekova, Fariza Mukasheva et al.

Osteochondral (OC) tissue plays a crucial role due to its ability to connect bone and cartilage tissues. To address the complexity of structure and functionality at the bone–cartilage interface, relevant to the presence of the tidemark as a critical element at the bone–cartilage boundary, we fabricated graded scaffolds through sequential 3D printing. The scaffold’s bottom layer was based on a gelatin/oxidized alginate mixture enriched with hydroxyapatite (HAp) to create a rougher surface and larger pores to promote osteogenesis. In contrast, the upper layer was engineered to have smaller pores and aimed to promote cartilage tissue formation and mimic the physical properties of the cartilage. An electrospun ε-polycaprolactone (PCL) membrane with micrometer-range pores was incorporated between the layers to replicate the function of tidemark—a barrier to prevent vascularization of cartilage from subchondral bone tissue. In vitro cell studies confirmed the viability of the cells on the layers of the scaffolds and the ability of PCL mesh to prevent cellular migration. The fabricated scaffolds were thoroughly characterized, and their mechanical properties were compared to native OC tissue, demonstrating suitability for OC tissue engineering and graft modeling. The distance of gradient of mineral concentration was found to be 151 µm for grafts and the native OC interface.

Qingchun Ji, Kehan Chen, Han Yi et al.

Delayed wound healing induced by bacterial infection and a persistent inflammatory response remains a great clinical challenge. Herein, we reported a paintable, anti-bacterial, and anti-inflammatory Nap-F3K-CA (Nap-Phe-Phe-Phe-Lys-Caffeic Acid) hydrogel for burn wound management based on caffeic acid (CA)-functionalized short peptides (Nap-Phe-Phe-Phe-Lys). Hydrogels are assembled by non-covalent interactions between gelators, and the incorporation of CA promotes the self-assembly of the hydrogel. After being applied to burn wounds, the hydrogel effectively adapted to irregular wound beds and maintained a moist protective environment at the wound. The Nap-F3K-CA hydrogel can scavenge ROS to relieve oxidative damage and downregulate proinflammatory levels. The Nap-F3K-CA hydrogel also displayed potent antibacterial activity against Gram-positive and Gram-negative bacteria, which reduced the incidence of wound infections. Moreover, the hydrogel exhibited good biocompatibility and hemostatic function. In vivo experiments demonstrated that the Nap-F3K-CA hydrogel significantly accelerated the repair of the skin structure including promoting collagen deposition, vascular regeneration, and hair follicle formation. These findings proved the clinical application potential of the Nap-F3K-CA hydrogel as a promising burn wound dressing.

Yufan Xie, Yuan Zhong, Jun Wu et al.

Under the increasing severity of drought issues and the urgent need for the resourceful utilization of agricultural waste, this study aimed to compare the soil water retention properties of hydrogels prepared from Chinese cabbage waste (CW) and banana peel (BP) using grafting techniques with acrylic acid (AA) and acrylamide (AAm). Free radical polymerization was initiated with ammonium persulfate (APS), and N, N′-methylene bisacrylamide (MBA) served as the crosslinking agent to fabricate the grafted polymer hydrogels. The hydrogels were subjected to detailed evaluations of their water absorption, reusability, and water retention capabilities through indoor experiments. The optimal hydrogel was identified and its applicability in wheat seedling growth was assessed. The findings revealed that the CW-gel, with an equilibrium swelling ratio of 551.8 g/g in ultrapure water, demonstrated remarkable performance and sustained a high water retention of 57.6% even after drying, which was markedly superior to that of the BP-gel. The CW-gel with the best comprehensive properties significantly improved water retention in sandy soil by 78.2% and prolonged the retention time by five days, indicating its potential for long-term irrigation management. In contrast, the BP-gel showed better performance in clay soil, with an increased water-holding capacity of 43.3%. The application of a 1.5% CW-gel concentration under drought stress significantly improved wheat seedling growth, highlighting the role of hydrogels in agriculture and providing a new path for sustainable water resource management in dryland farming.

Shaonan Wu, Shuai Lu, Yeyun Gong et al.

Formal proofs are challenging to write even for experienced experts. Recent progress in Neural Theorem Proving (NTP) shows promise in expediting this process. However, the formal corpora available on the Internet are limited compared to the general text, posing a significant data scarcity challenge for NTP. To address this issue, this work proposes Alchemy, a general framework for data synthesis that constructs formal theorems through symbolic mutation. Specifically, for each candidate theorem in Mathlib, we identify all invocable theorems that can be used to rewrite or apply to it. Subsequently, we mutate the candidate theorem by replacing the corresponding term in the statement with its equivalent form or antecedent. As a result, our method increases the number of theorems in Mathlib by an order of magnitude, from 110k to 6M. Furthermore, we perform continual pretraining and supervised finetuning on this augmented corpus for large language models. Experimental results demonstrate the effectiveness of our approach, achieving a 4.70% absolute performance improvement on Leandojo benchmark. Additionally, our approach achieves a 2.47% absolute performance gain on the out-of-distribution miniF2F benchmark based on the synthetic data.To provide further insights, we conduct a comprehensive analysis of synthetic data composition and the training paradigm, offering valuable guidance for developing a strong theorem prover.

Jennifer Voorhees, Simon Bailey, Heather Waterman et al.

Background Despite longstanding problems of access to general practice, attempts to understand and address the issues do not adequately include perspectives of the people providing or using care, nor do they use established theories of access to understand complexity. Aim To understand problems of access to general practice from the multiple perspectives of service users and staff using an applied theory of access. Design and setting A qualitative participatory case study in an area of northwest England. Method A community-based participatory approach was used with qualitative interviews, focus groups, and observation to understand perspectives about accessing general practice. Data were collected between October 2015 and October 2016. Inductive and abductive analysis, informed by Levesque et al’s theory of access, allowed the team to identify complexities and relationships between interrelated problems. Results This study presents a paradox of problems in accessing general practice, in which the demand on general practice both creates and hides unmet need in the population. Data show how reactive rules to control demand have undermined important aspects of care, such as continuity. The layers of rules and decreased continuity create extra work for practice staff, clinicians, and patients. Complicated rules, combined with a lack of capacity to reach out or be flexible, leave many patients, including those with complex and/or unrecognised health needs, unable to navigate the system to access care. This relationship between demand and unmet need exacerbates existing health inequities. Conclusion Understanding the paradox of access problems allows for different targets for change and different solutions to free up capacity in general practice to address the unmet need in the population.

Nolan Morrison, Brandon M. Vogel

Injectable, localized drug delivery using hydrogels made from ethoxylated trimethylolpropane tri-3-mercaptopropionate (ETTMP) and poly(ethylene glycol) diacrylate (PEGDA) has shown great potential due to these hydrogels’ ability to exhibit non-swelling behavior and tunable drug release properties. However, current synthesis methods in the literature suffer from poor ETTMP solubility in water, slow gelation times exceeding 20 min, and a lack of reproducibility. To address these limitations, we have developed a reliable synthesis procedure and conducted a sensitivity analysis of key variables. This has enabled us to synthesize ETTMP-PEGDA hydrogels in a polymer concentration range of 15 to 90 wt% with gelation times of less than 2 min and moduli ranging from 3.5 to 190 kPa. We overcame two synthesis limitations by identifying the impact of residual mercaptopropionic acid and alumina purification column height on gelation time and by premixing ETTMP and PEGDA to overcome low ETTMP solubility in water. Our ETTMP-PEGDA mixture can be stored at −20 °C for up to 2 months without crosslinking, allowing easy storage and shipment. These and previous results demonstrate the potential of ETTMP-PEGDA hydrogels as promising candidates for injectable, localized drug delivery with tunable drug release properties.

Aikaterini Gialouri, Sofia Falia Saravanou, Konstantinos Loukelis et al.

In this work, a sodium alginate-based copolymer grafted by thermoresponsive poly(<i>N</i>-isopropylacrylamide) (PNIPAM) chains was used as gelator (Alg-g-PNIPAM) in combination with methylcellulose (MC). It was found that the mechanical properties of the resulting gel could be enhanced by the addition of MC and calcium ions (Ca²⁺). The proposed network is formed via a dual crosslinking mechanism including ionic interactions among Ca²⁺ and carboxyl groups and secondary hydrophobic associations of PNIPAM chains. MC was found to further reinforce the dynamic moduli of the resulting gels (i.e., a storage modulus of ca. 1500 Pa at physiological body and post-printing temperature), rendering them suitable for 3D printing in biomedical applications. The polymer networks were stable and retained their printed fidelity with minimum erosion as low as 6% for up to seven days. Furthermore, adhered pre-osteoblastic cells on Alg-g-PNIPAM/MC printed scaffolds presented 80% viability compared to tissue culture polystyrene control, and more importantly, they promoted the osteogenic potential, as indicated by the increased alkaline phosphatase activity, calcium, and collagen production relative to the Alg-g-PNIPAM control scaffolds. Specifically, ALP activity and collagen secreted by cells were significantly enhanced in Alg-g-PNIPAM/MC scaffolds compared to the Alg-g-PNIPAM counterparts, demonstrating their potential in bone tissue engineering.

Sri Agung Fitri Kusuma, Muhammad Fadhlillah, Tina Rostinawati et al.

The production and purification of recombinant proteins are crucial to acquiring pure MPT64 protein. Due to the fact that protein epitopes may undergo conformational changes during purification, this study, therefore, investigated an effective rapid purification method to produce highly intracellular pure MPT64 protein without causing conformational changes in the epitope under denaturing conditions. MPT64 was isolated from <i>E. coli</i> and electrophoresed using gel SDS-PAGE. Then, the desired protein bands were excised and purified with two methods: electroelution and passive elution. The isolated protein was identified via peptide mass fingerprinting using MALDI-TOF MS and reacted with IgG anti-MPT64, and the cross-reactivity of the isolated protein with IgY anti-MPT64 was confirmed using Western blot. The results show that both of these methods produced pure MPT64 protein, and the MPT64 protein was confirmed based on the MALDI-TOF MS results. Neither of these two methods resulted in epitope changes in the MPT64 protein so it could react specifically with both antibodies. The yield of MPT64 protein was higher with electroelution (2030 ± 41 µg/mL) than with passive elution (179.5 ± 7.5 µg/mL). Thus, it can be inferred that the electroelution method is a more effective method of purifying MPT64 protein and maintaining its epitope than the passive elution method.

Nurul Saadah Said, Ibukunoluwa Fola Olawuyi, Won Young Lee

Pectin hydrogels have garnered significant attention in the food industry due to their remarkable versatility and promising properties. As a naturally occurring polysaccharide, pectin forms three-dimensional (3D) hydrophilic polymer networks, endowing these hydrogels with softness, flexibility, and biocompatibility. Their exceptional attributes surpass those of other biopolymer gels, exhibiting rapid gelation, higher melting points, and efficient carrier capabilities for flavoring and fat barriers. This review provides an overview of the current state of pectin gelling mechanisms and the classification of hydrogels, as well as their crosslinking types, as investigated through diverse research endeavors worldwide. The preparation of pectin hydrogels is categorized into specific gel types, including hydrogels, cryogels, aerogels, xerogels, and oleogels. Each preparation process is thoroughly discussed, shedding light on how it impacts the properties of pectin gels. Furthermore, the review delves into the various crosslinking methods used to form hydrogels, with a focus on physical, chemical, and interpenetrating polymer network (IPN) approaches. Understanding these crosslinking mechanisms is crucial to harnessing the full potential of pectin hydrogels for food-related applications. The review aims to provide valuable insights into the diverse applications of pectin hydrogels in the food industry, motivating further exploration to cater to consumer demands and advance food technology. By exploiting the unique properties of pectin hydrogels, food formulations can be enhanced with encapsulated bioactive substances, improved stability, and controlled release. Additionally, the exploration of different crosslinking methods expands the horizons of potential applications.

Roya Binaymotlagh, Farid Hajareh Haghighi, Enea Gino Di Domenico et al.

The photoantibacterial properties of titania nanoparticles (TiO₂NPs) are attracting much interest, but the separation of their suspension limits their application. In this study, the encapsulation of commercial TiO₂NPs within self-assembling tripeptide hydrogels to form hgel-TiO₂NP composites with significant photoantibacterial properties is reported. The Fmoc-Phe₃ hydrogelator was synthesized via an enzymatic method. The resulting composite was characterized with DLS, ζ-potential, SAXS, FESEM-EDS and rheological measurements. Two different concentrations of TiO₂NPs were used. The results showed that, by increasing the TiO₂NP quantity from 5 to 10 mg, the value of the elastic modulus doubled, while the swelling ratio decreased from 63.6 to 45.5%. The antimicrobial efficacy of hgel-TiO₂NPs was tested against a laboratory <i>Staphylococcus aureus</i> (<i>S. aureus</i>) strain and two methicillin-resistant <i>S. aureus</i> (MRSA) clinical isolates. Results highlighted a concentration-dependent superior antibacterial activity of hgel-TiO₂NPs over TiO₂NPs in the dark and after UV photoactivation. Notably, UV light exposure substantially increased the biocidal action of hgel-TiO₂NPs compared to TiO₂NPs. Surprisingly, in the absence of UV light, both composites significantly increased <i>S. aureus</i> growth relative to control groups. These findings support the role of hgel-TiO₂NPs as promising biocidal agents in clinical and sanitation contexts. However, they also signal concerns about TiO₂NP exposure influencing <i>S. aureus</i> virulence.

Hossein Omidian, Sumana Dey Chowdhury

Injectable hydrogels have gained popularity for their controlled release, targeted delivery, and enhanced mechanical properties. They hold promise in cardiac regeneration, joint diseases, postoperative analgesia, and ocular disorder treatment. Hydrogels enriched with nano-hydroxyapatite show potential in bone regeneration, addressing challenges of bone defects, osteoporosis, and tumor-associated regeneration. In wound management and cancer therapy, they enable controlled release, accelerated wound closure, and targeted drug delivery. Injectable hydrogels also find applications in ischemic brain injury, tissue regeneration, cardiovascular diseases, and personalized cancer immunotherapy. This manuscript highlights the versatility and potential of injectable hydrogel nanocomposites in biomedical research. Moreover, it includes a perspective section that explores future prospects, emphasizes interdisciplinary collaboration, and underscores the promising future potential of injectable hydrogel nanocomposites in biomedical research and applications.

William J. Wolf, James Read, Quentin Vigneron

The geometric trinity of gravity comprises three distinct formulations of general relativity: (i) the standard formulation describing gravity in terms of spacetime curvature, (ii) the teleparallel equivalent of general relativity describing gravity in terms of spacetime torsion, and (iii) the symmetric teleparallel equivalent of general relativity (STEGR) describing gravity in terms of spacetime non-metricity. In this article, we complete a geometric trinity of non-relativistic gravity, by (a) taking the non-relativistic limit of STEGR to determine its non-relativistic analogue, and (b) demonstrating that this non-metric theory is equivalent to the Newton--Cartan theory and its teleparallel equivalent, i.e., the curvature and the torsion based non-relativistic theories that are both geometrised versions of classical Newtonian gravity.

L. Huibers, B. Bech, Ulrik Bak Kirk et al.

Background The COVID-19 pandemic has altered the provision of health care and expanded telehealth consultations. Aim To study the effect of the COVID-19 pandemic on contact patterns in general practice, and to identify patient groups at risk of losing care. Design and setting Register-based study of Danish general practice, including daytime and out-of-hours (OOH) services. Method All individuals residing in Denmark from 1 January 2017 to 31 October 2020 were included. The incidence rate for six contact types in general practice and adjusted incidence rate ratio were calculated by comparing the incidence rate in the pandemic period with the adjusted expected incidence rate based on the incidence rate in the pre-pandemic period. Results The number of face-to-face in-clinic consultations declined during the lockdown in March 2020. A subsequent increase in the number of clinic consultations was observed, rising to a level above that of the pre-pandemic period; this increase resulted mainly from the introduction of telehealth consultations (that is, video and extended telephone). The number of daytime email consultations increased, whereas the number of daytime home visits decreased. Likewise, the number of OOH telephone consultations increased, whereas the number of OOH home visits and clinic consultations decreased. Consultation rates of patients who are vulnerable, that is, those with low education, old age, and comorbidity, were most adversely affected by the pandemic. The most adverse impact in OOH clinic consultations was seen for children aged 0–9 years. Conclusion New methods are called for to ensure access to general practice for patients who are vulnerable during a pandemic. The potential of telehealth consultations should be further investigated.

Julian Wangler, M. Jansky

Abstract Background There is currently no cure for dementia but general practitioners (GPs) have therapeutic options available to counteract the progression of mild cognitive impairment, including drug and non-drug treatment. So far, few studies have investigated treatment strategies preferred by GPs. Objectives This study aimed to gain an overview of GPs’ attitudes towards influencing the progression of dementia, their involvement regarding dementia prevention and perceived effective approaches. It also elucidated the challenges experienced by GPs and desired optimisation measures towards reinforcing secondary prevention. Methods Between June 2020 and March 2021, 64 semi-standardised interviews amongst GPs were conducted in all federal states of Germany. Thirty interviews were carried out in person and 34 by phone. The data were analysed according to qualitative content analysis. Results Many interviewees see great importance in secondary dementia prevention and believe they could make an effective contribution, some of them using non-drug approaches. GPs play a role in guiding patients and relatives towards support services. Some doctors consider drug treatment as the only option towards influencing the progression of dementia, showing low expectations on self-efficacy. Interdisciplinary collaboration is a frequent challenge, which often conflicts with a coherent treatment strategy. Conclusion Many GPs feel confident about influencing the progression of dementia and believe they can intervene effectively, using various (non-drug) treatment measures and referrals to support services. GPs perceive challenges, including obstacles in interdisciplinary collaboration and negative impacts after drug administration. To improve the conditions for GP intervention, it depends on expanding interdisciplinary collaboration and care strategies.