Hasil untuk "General. Including alchemy"

Rocco P. Viggiano, James Wu, Daniel A. Scheiman et al.

Advanced aerospace vehicle concepts demand concurrent advances in energy storage technologies that improve both specific energy and safety. Commercial lithium-ion batteries commonly employ polyolefin microporous separators and carbonate-based liquid electrolytes, which can deliver room-temperature ionic conductivities on the order of 10⁻³–10⁻² S/cm but rely on inherently flammable solvents. Room-temperature ionic liquids (RTILs) offer a nonvolatile, nonflammable alternative with a stable electrochemical window; however, many RTILs exhibit poor compatibility and wetting with polyolefin separators. Here, we evaluate highly porous, cross-linked polyimide (PI) gel separators based on 4,4′-oxydianiline (ODA) and biphenyl-3,3′,4,4′-tetracarboxylic dianhydride (BPDA), cross-linked with Desmodur N3300A, formulated with repeating unit lengths (n) of 30 and 60. These PI gel separators exhibit an open, fibrillar network with high porosity (typically >85%), high thermal stability (onset decomposition > 561 °C), and high char yield. Six imidazolium-based RTILs containing 10 wt% LiTFSI were screened, yielding nonflammable separator/electrolyte systems with room-temperature conductivities in the 10⁻³ S/cm range. Among the RTILs studied, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM-TFSI) provided the best overall performance. Ionic conductivity and its retention after four months of storage at 75 °C were evaluated in the EMIM-TFSI/LiTFSI system, and the corresponding gel separator exhibited a tensile modulus of 26.66 MPa. Collectively, these results demonstrate that PI gel separators can enable carbonate-free, nonflammable RTIL electrolytes while maintaining the ionic conductivity suitable for lithium-based cells.

Zhe Liu, Dongfang Wang, Yan Zhu et al.

In this study, a bio-based adsorbent, quaternary ammonium-modified cationic chitosan fibers (CCFs), were developed and systematically evaluated for fluoride removal from low-concentration aqueous medium, with particular emphasis on adsorption performance, regeneration behavior, practical applicability, and adsorption mechanisms. The results demonstrate that the fluoride adsorption capacity of CCFs is approximately 15.8 times higher than that of unmodified chitosan fibers (CFs). Furthermore, CCFs exhibit superior fluoride adsorption capacity and remarkably rapid kinetics relative to previously reported chitosan-based adsorbents in the literature. The adsorption process fits well with the pseudo-second-order kinetic model and reaches equilibrium within 10 min. Adsorption isotherm data are well described by both Langmuir and Freundlich models, with a maximum adsorption capacity of 28.5 mg/g. CCFs also show excellent regeneration performance, achieving efficient fluoride desorption within 3 min using a 0.02 mol/L NaCl solution, with no noticeable loss in adsorption capacity after five consecutive adsorption–desorption cycles. The adsorption performance remains effective in natural surface water containing competing ions. Mechanistic investigations reveal that fluoride adsorption is dominated by electrostatic attraction between quaternary ammonium groups (R₄N⁺) on the CCFs surface and fluoride ions, accompanied by ion exchange with chloride ions. Owing to their high efficiency, rapid kinetics, metal-free nature, and facile regeneration, the CCFs developed in this study represent a promising bio-based adsorbent for the advanced purification of low-concentration fluoride-containing water.

Peng Zhang, Baozhi Shi, Xiaobing Dai et al.

Geopolymer, as a sustainable, low-carbon gel binder, is regarded as a potential alternative to cement. Freeze–thaw (F-T) resistance, which has a profound influence on the service life of structures, is a crucial indicator for assessing the durability of geopolymer composites (GCs). Consequently, comprehending the F-T resistance of GCs is of the utmost significance for their practical implementation. In this article, a comprehensive and in-depth review of the F-T resistance of GCs is conducted. This review systematically synthesizes several frequently employed theories regarding F-T damage, with the aim of elucidating the underlying mechanisms of F-T damage in geopolymers. The factors influencing the F-T resistance of GCs, including raw materials, curing conditions, and modified materials, are meticulously elaborated upon. The results indicate that the F-T resistance of GCs can be significantly enhanced through using high-calcium-content precursors, mixed alkali activators, and rubber aggregates. Moreover, appropriately increasing the curing temperature has been shown to improve the F-T resistance of GCs, especially for those fabricated with low-calcium-content precursors. Among modified materials, the addition of most fibers and nano-materials remarkably improves the F-T resistance of GCs. Conversely, the effect of air-entraining agents on the F-T resistance of GCs seems to be negligible. Furthermore, evaluation and prediction models for the F-T damage of GCs are summarized, including empirical models and machine learning models. In comparison with empirical models, the models established by machine learning algorithms exhibit higher predictive accuracy. This review promotes a more profound understanding of the factors affecting the F-T resistance of GCs and their mechanisms, providing a basis for engineering and academic research.

Xin Zhang, Jiarong Liang, Binglei Zheng et al.

Elevated levels of homocysteine (Hcy) are associated with various pathological conditions including atherosclerosis, hypertension, and cardiovascular diseases. In this work, quantum-dot-based molecularly imprinted hydrogels (QD@MIHs) were developed by integrating L-cysteine-modified ZnS quantum dots (QDs)with highly selective molecular imprinting technology for rapid homocysteine detection. The QD@MIPHs were fabricated using a dual-functional monomer system (acrylamide and methacrylic acid) through surface coating of the Hcy molecularly imprinted polymer gel onto the QDs. Under optimal conditions, the response time of the QD@MIPHs for Hcy detection was 5 min. When the Hcy concentration ranged from 0.1 to 10.0 μM, the fluorescence quenching of the QD@MIHs showed a good linear relationship with Hcy concentration (<i>R</i>² = 0.9972), with a corresponding detection limit of 0.027 μM. In addition, the constructed QD@MIPHs showed no significant response to other interfering substances, demonstrating the high selectivity of the prepared material. Practical sample analysis revealed that the recovery rates of Hcy ranged from 94.34% to 104.1%, with relative standard deviations (RSD, <i>n</i> = 3) between 3.56% and 7.17%. This study provides a novel tool and method for rapid Hcy detection with significant potential in biomedical diagnostics and preventive-healthcare applications.

Youxi Zhou, Kaizhao Chen, Hongwei Cheng et al.

Immunotherapy has revolutionized cancer treatment and led to a significant increase in patient survival rates and quality of life. However, the effectiveness of current immunotherapies is limited by various factors, including immune evasion mechanisms and serious side effects. Hydrogels are a type of medical material with an ideal biocompatibility, variable structure, flexible synthesis method, and physical properties. Hydrogels have long been recognized and used as a superior choice for various biomedical applications. The fascinating results were derived from both in vitro and in vivo models. The rapid expansion of this area suggests that the principles and uses of functionalized polysaccharides are transformative, motivating researchers to investigate novel polysaccharide-based hydrogels for wider applications. Polysaccharide hydrogels have proven to be a practicable delivery strategy for tumor immunotherapy due to their biocompatibility, biodegradability, and pronounced bioactive characteristics. This study aims to examine in detail the latest developments of polysaccharide hydrogels in tumor immunotherapy, focusing on their design, mechanism of action, and potential therapeutic applications.

Yunxia Yang, Hongmei Zhang, Xueqing Zhang et al.

Bacterial infections cause serious problems associated with wound treatment and serious complications, leading to serious threats to the global public. Bacterial resistance was mainly attributed to the formation of biofilms and their protective properties. Hydrogels suitable for irregular surfaces with effective antibacterial activity have attracted extensive attention as potential materials. In this study, a succinoglycan-riclin-zinc-phthalocyanine-based composite (RL-Zc) hydrogel was synthesized through an amine reaction within an hour. The hydrogel was characterized via FT-IR, SEM, and rheology analysis, exhibiting an elastic solid gel state stably. The hydrogel showed large inhibition circles on <i>E. coli</i> as well as <i>S. aureus</i> under near-infrared irradiation (NIR). RL-Zc hydrogel exhibited positively charged surfaces and possessed a superior penetrability toward bacterial biofilm. Furthermore, RL-Zc hydrogel generated abundant single oxygen and mild heat rapidly, resulting in disrupted bacterial biofilm as well as amplified antibacterial effectiveness. A metabolomics analysis confirmed that RL-Zc hydrogel induced a metabolic disorder in bacteria, which resulted from phospholipid metabolism and oxidative stress metabolism related to biofilm disruption. Hence, this study provided a potential phototherapy for biofilm-induced bacterial resistance.

L. Filipe O. Costa, Francisco Frutos-Alfaro, José Natário et al.

In a recent paper we discussed when it is possible to define reference frames nonrotating with respect to distant inertial reference objects (extension of the IAU reference systems to exact general relativity), and how to construct them. We briefly review the construction, illustrating it with further examples, and caution against the recent misuse of zero angular momentum observers (ZAMOs).

Yuhao Jiang, Junfeng Qiao, Nataliya Paulish et al.

Maximally-localized Wannier functions (MLWFs) are widely employed as an essential tool for calculating the physical properties of materials due to their localized nature and computational efficiency. Projectability-disentangled Wannier functions (PDWFs) have recently emerged as a reliable and efficient approach for automatically constructing MLWFs that span both occupied and lowest unoccupied bands. Here, we extend the applicability of PDWFs to magnetic systems and/or those including spin-orbit coupling, and implement such extensions in automated workflows. Furthermore, we enhance the robustness and reliability of constructing PDWFs by defining an extended protocol that automatically expands the projectors manifold, when required, by introducing additional appropriate hydrogenic atomic orbitals. We benchmark our extended protocol on a set of 200 chemically diverse materials, as well as on the 40 systems with the largest band distance obtained with the standard PDWF approach, showing that on our test set the present approach delivers a 100% success rate in obtaining accurate Wannier-function interpolations, i.e., an average band distance below 15 meV between the DFT and Wannier-interpolated bands, up to 2 eV above the Fermi level.

Shutong Du, Xiaohu Zhou, Bo Zheng

Extracellular vesicles (EVs), especially exosomes, have shown great therapeutic potential in the treatment of diseases, as they can target cells or tissues. However, the therapeutic effect of EVs is limited due to the susceptibility of EVs to immune system clearance during transport in vivo. Hydrogels have become an ideal delivery platform for EVs due to their good biocompatibility and porous structure. This article reviews the preparation and application of EVs-loaded hydrogels as a cell-free therapy strategy in the treatment of diseases. The article also discusses the challenges and future outlook of EVs-loaded hydrogels.

Maria-Alexandra Paun, Vladimir-Alexandru Paun, Viorel-Puiu Paun

This article portrays solid xerogel-type materials, based on chitosan, TEGylated phenothiazine, and TEG (tri-ethylene glycol), dotted with a large number of pores, that are effectively represented in their constitutive structure. They were assumed to be fractal geometrical entities and adjudged as such. The acoustic fractional propagation equation in a fractal porous media was successfully applied and solved with the help of Bessel functions. In addition, the fractal character was demonstrated by the produced fractal analysis, and it has been proven on the evaluated scanning electron microscopy (SEM) pictures of porous xerogel compounds. The fractal parameters (more precisely, the fractal dimension), the lacunarity, and the Hurst index were calculated with great accuracy.

M. Bouvier, S. Viti, E. Behrens et al.

Sulphur-bearing species are detected in various environments within Galactic star-forming regions and are particularly abundant in the gas phase of outflows and shocks, and photo-dissociation regions. In this work, we aim to investigate the nature of the emission from the most common sulphur-bearing species observable at millimetre wavelengths towards the nuclear starburst of the galaxy NGC 253. We intend to understand which type of regions are probed by sulphur-bearing species and which process(es) dominate(s) the release of sulphur into the gas phase. We used the high-angular resolution (1.6" or 27 pc) observations from the ALCHEMI ALMA Large Program to image several sulphur-bearing species towards the central molecular zone (CMZ) of NGC 253. We performed local thermodynamic equilibrium (LTE) and non-LTE large velocity gradient (LVG) analyses to derive the physical conditions of the gas in which S-bearing species are emitted, and their abundance ratios across the CMZ. Finally, we compared our results with previous ALCHEMI studies and a few selected Galactic environments. We found that not all sulphur-bearing species trace the same type of gas: strong evidence indicates that H2S and part of the emission of OCS, H2CS, and SO, are tracing shocks whilst part of SO and CS emission rather trace the dense molecular gas. For some species, such as CCS and SO2, we could not firmly conclude on their origin of emission. The present analysis indicates that the emission from most sulphur-bearing species throughout the CMZ is likely dominated by shocks associated with ongoing star formation. In the inner part of the CMZ where the presence of super star clusters was previously indicated, we could not distinguish between shocks or thermal evaporation as the main process releasing the S-bearing species.

Susobhan Mandal, S. Shankaranarayanan

General relativity and quantum field theory are the cornerstones of our understanding of physical processes, from subatomic to cosmic scales. While both theories work remarkably well in their tested domains, they show minimal overlap. However, our research challenges this separation by revealing that non-perturbative effects bridge these distinct domains. We introduce a novel mechanism wherein, at linear order, spin-2 fields around an arbitrary background acquire \emph{effective mass} due to the spontaneous symmetry breaking (SSB) of either global or local symmetry of complex scalar field minimally coupled to gravity. The action of the spin-2 field is identical to the extended Fierz-Pauli (FP) action, corresponding to the mass deformation parameter $α= 1/2$. We show that this occurs due to the effect of SSB on the variation of the energy-momentum tensor of the matter field, which has a dominant effect during SSB. The extended FP action has a salient feature, compared to the standard FP action: the action has 6 degrees of freedom with no ghosts. For local $U(1)$ SSB, we establish that the effective mass of spin-2 fields is related to the mass of the gauge boson and the electric charge of the complex scalar field. Interestingly, our results indicate that the millicharged dark matter scalar fields, generating dark photons, can produce a mass of spin-2 fields of the same order as the Hubble constant $(H_0)$. Hence, we argue that the dark sector offers a natural explanation for the acceleration of the current Universe.

Jann Zosso

Guided by the Einstein equivalence principle that identifies the phenomenon of gravitation as a manifestation of the dynamics of spacetime in contrast to a localizable force, we review and explore its consequences on formulating a theory of gravity. The resulting space of metric theories of gravity may address open conceptual and observational puzzles through a wealth of effects beyond general relativity, whose traces can be searched for within today's and tomorrow's gravitational testing grounds. Above all, we offer a generic metric theory generalization of Isaacson's approach to the leading-order field equations of physical perturbations with a well-defined notion of energy-momentum carried by the gravitational waves. Within this framework, we identify the backreaction of the Isaacson energy-momentum flux onto the background spacetime with the displacement memory effect that induces a permanent distortion of space after the passage of a gravitational wave. This effect is a well-known prediction of GR whose dominant contribution captures its inherent non-linear nature, manifest in the ability of gravity to gravitate. However, the novel interpretation of memory as naturally arising within the Isaacson approach to gravitational waves comes with two main advantages. Firstly, it allows for a unified understanding of both the null and the ordinary memory effect, which are respectively sourced by unbound energy fluxes that do and do not reach asymptotic null infinity. Secondly, and most importantly, this approach allows for a consistent derivation of the memory formula for a large class of metric theories with considerable lessons to be learned for upcoming future measurements of the memory effect.

Chengbo Yuan, Chuan Wen, Tong Zhang et al.

We address the challenge of acquiring real-world manipulation skills with a scalable framework. We hold the belief that identifying an appropriate prediction target capable of leveraging large-scale datasets is crucial for achieving efficient and universal learning. Therefore, we propose to utilize 3D flow, which represents the future trajectories of 3D points on objects of interest, as an ideal prediction target. To exploit scalable data resources, we turn our attention to human videos. We develop, for the first time, a language-conditioned 3D flow prediction model directly from large-scale RGBD human video datasets. Our predicted flow offers actionable guidance, thus facilitating zero-shot skill transfer in real-world scenarios. We deploy our method with a policy based on closed-loop flow prediction. Remarkably, without any in-domain finetuning, our method achieves an impressive 81\% success rate in zero-shot human-to-robot skill transfer, covering 18 tasks in 6 scenes. Our framework features the following benefits: (1) scalability: leveraging cross-embodiment data resources; (2) wide application: multiple object categories, including rigid, articulated, and soft bodies; (3) stable skill transfer: providing actionable guidance with a small inference domain-gap. Code, data, and supplementary materials are available https://general-flow.github.io

Dylan Galt, Langte Ma

We study generalized anti-self-dual instantons defined over Riemannian manifolds equipped with a parallel codimension-$4$ differential form. In particular, for product Riemannian manifolds possessing such a form, we study dimension reduction phenomena, finding a topological criterion for bundles which, when satisfied, allows for a complete characterization of dimension reduction for the corresponding moduli space of generalized ASD instantons. By establishing an integrability result for families of connections, we then deduce explicit descriptions for these moduli spaces, including those of Hermitian Yang--Mills connections, $G_2$-, and $\Spin(7)$-instantons. When one factor in the product is a $4$-manifold, we establish well-behaved compactifications for these moduli spaces.

Charles Coombs, T. Cohen, C. Duddy et al.

Background International trends have shifted to creating large general practices. There is an assumption that interdisciplinary teams will increase patient accessibility and provide more cost-effective, efficient services. Micro-teams have been proposed to mitigate for some potential challenges of practice expansion, including continuity of care. Aim To review available literature and examine how micro-teams are described, and identify opportunities and limitations for patients and practice staff. Design and setting This was an international systematic review of studies published in English. Method Databases (MEDLINE, EMBASE, CINAHL, Cochrane Library, and Scopus) and grey literature were searched. Studies were included if they provided evidence about implementation of primary care micro-teams. Framework analysis was used to synthesise identified literature. The research team included a public contributor co-applicant. The authors conducted stakeholder discussions with those with and without experience of micro-team implementation. Results Of the 462 studies identified, 24 documents met the inclusion criteria. Most included empirical data from healthcare professionals, describing micro-team implementation. Results included characteristics of the literature; micro-team description; range of ways micro-teams have been implemented; reported outcomes; and experiences of patients and staff. Conclusion The organisation of primary care has potential impact on the nature and quality of patient care, safety, and outcomes. This review contributes to current debate about care delivery and how this can impact on the experiences and outcomes of patients and staff. This analysis identifies several key opportunities and challenges for future research, policy, and practice.

Alessandra A Pratt, Anne G. Sadler, E. Thomas et al.

BACKGROUND Our aim was to determine rates of postpartum mood and anxiety disorders (PMADs) among U.S. women Veterans and the overlap among PMADs. We further sought to identify PMAD risk factors, including those unique to military service. METHODS A national sample of women Veterans completed a computer-assisted telephone interview (N = 1414). Eligible participants were aged 20-45 and had separated from service within the last 10 years. Self-report measures included demographics, general health, reproductive health, military exposures, sexual assault, childhood trauma, and posttraumatic stress disorder (PTSD). The PMADs of interest were postpartum depression (PPD), postpartum anxiety (PPA) and postpartum PTSD (PPPTSD). This analysis included 1039 women Veterans who had ever been pregnant and who answered questions about PPMDs related to their most recent pregnancy. RESULTS A third (340/1039, 32.7%) of participants were diagnosed with at least one PMAD and one-fifth (215/1039, 20.7%) with two or more. Risk factors common for developing a PMAD included: a mental health diagnosis prior to pregnancy, a self-report of ever having had a traumatic birth experience, and most recent pregnancy occurring during military service. Additional risk factors were found for PPD and PPPTSD. CONCLUSION Women Veterans may be at an increased risk for developing PMADs due to high rates of lifetime sexual assault, mental health disorders, and military-specific factors including giving birth during military service and military combat deployment exposures.

Wei Lin, C. Chung, Changhong Zhao

The fast development of energy storage is attracting attention in storage-concerned power system optimization. The complementarity constraints of energy storage introduce non-convexity, which increases the complexity of power system optimization. To circumvent such non-convexity, this paper studies the relaxation for the inherent fulfillment of complementarity constraints in general storage-concerned power system optimization. This paper first develops a linear constraint to replace the complementarity constraint in the original optimization problem. It is proven that the resulting solution can be recovered to a feasible solution of the original problem. Backed by the previous feasibility guarantee, this paper further studies the ex-ante sufficient conditions with which the optimality of the original problem will not be affected under the relaxation of complementarity constraints. Numerical experiments in five transmission and distribution systems, including four IEEE test systems and one utility system, verify the effectiveness of the proposed method.

Mohammed Ghazwani, Umme Hani, Aftab Alam et al.

Niosomes are multilamellar vesicles that effectively transfer active ingredients into the skin’s layers. To improve the active substance’s penetration across the skin, these carriers are frequently utilized as topical drug delivery systems. Essential oils (EOs) have garnered significant interest in the field of research and development owing to their various pharmacological activities, cost-effectiveness, and simple manufacturing techniques. However, these ingredients undergo degradation and oxidation over time, leading to a loss of functionality. Niosome formulations have been developed to deal with these challenges. The main goal of this work was to create a niosomal gel of carvacrol oil (CVC) to improve its penetration into the skin for anti-inflammatory actions and stability. By changing the ratio of drug, cholesterol and surfactant, various formulations of CVC niosomes were formulated using Box Behnken Design (BBD). A thin-film hydration technique using a rotary evaporator was employed for the development of niosomes. Following optimization, the CVC-loaded niosomes had shown: 180.23 nm, 0.265, −31.70 mV, and 90.61% of vesicle size, PDI, zeta potential, and EE%. An in vitro study on drug release discovered the rates of drug release for CVC-Ns and CVC suspension, which were found to be 70.24 ± 1.21 and 32.87 ± 1.03, respectively. The release of CVC from niosomes best fit the Higuchi model, and the Korsmeyer–Peppas model suggests that the release of the drug followed the non-Fickian diffusion. In a dermatokinetic investigation, niosome gel significantly increased CVC transport in the skin layers when compared to CVC–conventional formulation gel (CVC-CFG). Confocal laser scanning microscopy (CLSM) of rat skin exposed to the rhodamine B-loaded niosome formulation showed a deeper penetration of 25.0 µm compared to the hydroalcoholic rhodamine B solution (5.0 µm). Additionally, the CVC-N gel antioxidant activity was higher than that of free CVC. The formulation coded F4 was selected as the optimized formulation and then gelled with carbopol to improve its topical application. Niosomal gel underwent tests for pH determination, spreadability, texture analysis, and CLSM. Our findings imply that the niosomal gel formulations could represent a potential strategy for the topical delivery of CVC in the treatment of inflammatory disease.

Matteo Sambucci, Seyed Mostafa Nouri, Sara Taherinezhad Tayebi et al.

A new hybrid fiber blend containing microfibrillated cellulose (MFC) gel and recycled carbon short fiber (RCSF) was implemented for designing fiber-reinforced cement mortars, to further improve the mechanical properties and enhance the sustainability of cement-based materials. The individual impact of single fibrous fillers as well as the synergistic effect of a hybrid fiber system (MFC + RCSF) were investigated in terms of the rheological properties, mechanical strength, and microstructure of the mortars. The results indicated that the workability of fresh mixtures slightly increased after fiber addition. The fibers incorporated alone improved the materials’ performance in different ways. The addition of RCSF led to improvements of up to 76% in flexural strength and 13% in compression strength for a fiber content of 0.75 wt.%. However, the addition of carbon fibers led to slight deteriorations in terms of porosity and water absorption. On the other hand, the use of MFC induced a less significant growth in terms of mechanical strength (+14% in flexural strength for 0.75 wt.% of cellulose) but greatly improved the microstructural quality of the mortar, significantly reducing its water permeability. Considering the optimum MFC dosage, MFC+RCSF hybrid mixtures showed positive effects on the mechanical properties and microstructure of the mortar, displaying further improvements in strength, while preserving a lower porosity and water absorption than the control mix.