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Developing an imperialist competitive algorithm based on two improvement strategies in a hierarchical capacitated health network
No full textThe present paper on the location of clinic (C), hospital (H) and medical center (MC) in the Golestan province of Iran is motivated by its present condition coming from limited distribution and ease of access for related Cs, Hs, and MCs. Design of a median hierarchical location-allocation model for the needed healthcare facilities, from Cs to Hs and MCs, is a vital and valuable activity from the emergency viewpoints of both patients and the government. This model has been formulated as a mixed-integer linear mathematical framework for finding the optimal location of these capacitated healthcare facilities, the allocation of patients to these Cs, Hs, or MCs and also for the referrals of the patients' needs to them while minimizing the total demand-weighted travel distance. This problem is in the category of an NP-hard problem. An efficient and robust imperialist competitive algorithm based on two initialization and local mechanisms is also presented to improve the computational time and accuracy of simulation results. Comparative performance of the developed method with some well-known metaheuristics has been surveyed using a real case study for the healthcare network for different problems with a change in the model parameters' values. The novel method is reliable and valid according to accuracy and execution time. The sensitivity analysis results concerning the maximum number of locations (i.e., Cs, Hs and MCs). Furthermore, the percent of the referred demand determines the significance and practical observations related to the combination of the Cs, Hs, and MCs to be established. Our new model is illustrated to be gainful as it offers a robust build plan to designers for making location decisions for developing the Golestan healthcare network
Light-responsive liposome as a smart vehicle for the delivery of anticancer herbal medicine to skin
No full textSunlight is composed of various wavelengths, including visible light, ultraviolet (UV) rays, and infrared radiation that serves as a double-edged sword for humans via providing the energy for sustaining life on Earth and also acting as a source of hazardous UV radiation. The skin, as the largest protective part of the body, is exposed to sunlight daily, making it critical to protect this organ from its harmful effects. Accordingly, this research aims to fabricate a new type of light-responsive liposome to deliver herbal medicine as protective compounds with antioxidant and anticancer properties. The light-responsive part of this liposome has the capability of cleavage after exposure to UV-A light (the main UV-parts of sunlight) and improves drug release pattern. In detail, a light-responsive compound was fabricated at first and then was used along with phospholipids and curcumin (a type of herbal drug)-loaded cyclodextrin for the fabrication of liposomes using the thin-film hydration method. The physicochemical analysis confirmed the fabrication of spherical liposomes approximately 145 nm in size, which released around 62% of the therapeutic cargo over 120 h when exposed to UV irradiation. Besides, it showed anticancer ability (against melanoma cancer cells) while having a protecting effect for the normal cell line. Therefore, it could be a candidate for further application in skin-protecting products like wound healing compounds or anticancer usage
Curing properties of covalently bonded polyoxazoline-imidazole thermal latent curing agents for one-component epoxy resins
Get PDFEpoxy resins are the most commonly utilized resins for the fabrication of polymer matrix composites. One-component epoxy resins (OCERs) are commonly utilized since they are easier to process, have a longer shelf life, produce higher-end products, and use less energy than two-component epoxy resins. Increasing the shelf life and modifying the curing temperature are crucial for OCERs. To address stability issues in OCERs, latent curing agents are employed. In this study, polyoxazoline-imidazole (POZ-Im) thermal latent curing agents (TLCs) were prepared by synthesizing different types of POZs and terminating them with imidazole. Diglycidyl ether bisphenol A (DGEBA) resin was mixed with POZ-Im TLCs to produce OCERs, and the curing behavior of the resulting OCERs was examined with DSC. The stability, uniformity, and thermal latency behavior of the OCERs were examined in relation to the hydrophilicity of the POZ
The effects of geopolitical and political risks on corporate ESG practices
No full textThis study examines how companies modify their environmental, social, and governance (ESG) practices in reaction to geopolitical and political risks, presenting a unique empirical methodology that simultaneously addresses internal (political) and external (geopolitical) macroeconomic vulnerabilities. We use a comprehensive firm-level sample of 37 countries from 2002 to 2022 (42,587 firm years). Utilizing risk management and financial resilience theory, we define ESG as a dynamic, responsive mechanism by which corporations alleviate undiversifiable shocks. Utilizing a lead-lag autoregressive methodology on a cross-country firm-level panel, we demonstrate that ESG participation escalates in reaction to increasing risk levels; however, it exhibits systematic variation based on firm ESG maturity, industry attributes, and risk categories. Companies with inferior ESG scores have a more pronounced reaction to political instability, whereas those with superior ESG performance respond more acutely to geopolitical upheavals. Significantly, we reveal varied reactions across ESG pillars: environmental performance typically declines under geopolitical stress, whereas social and governance aspects frequently remain stable or enhance, indicating short-term adaptive tactics. Sectoral elements, like energy intensity and competitive pressure, further influence ESG reactions. Our findings provide fresh insights into the environmental management consequences of systemic risk exposure, emphasizing the necessity for supportive legislative frameworks and risk-sensitive ESG structures. This study enhances the existing literature on business sustainability by highlighting the strategic importance of ESG in improving environmental resilience during unstable geopolitical conditions
Experimental and numerical analysis of damage progression in composite cylinders with cutouts under combined loading using structural health monitoring techniques
No full textThe study investigates the damage progression within a long and hollow axisymmetric composite cylinder with central cutouts, employing both experimental and numerical approaches. The composite cylinder, with a radius-to-thickness ratio of 10 and a length-to-diameter ratio of 10.5 tested under combine loading condition (torsion and compression). Damage accumulation is investigated using acoustic emission, infrared thermography, digital image correlation, and strain gauges. Unsupervised machine learning techniques are utilized to analyze acoustic emission data, facilitating the clustering of damages, with matrix cracking identified as the predominant failure mode resulting from shear stresses. The distribution of failure types varies across the cylinder, culminating in catastrophic failures resulting from the concurrent appearance of these events. A thermal camera captures temperature changes during failure, offering insights into damage initiation and post-global failure. The utilization of the digital image correlation technique enables the acquisition of full-field surface displacement measurements within the specimen including an open hole, thereby revealing the consequential effects of these displacements on the mechanism of failure. Linear static analysis and stiffness reduction-based progressive damage analysis are performed in the Ansys, which underscores study reliability demonstrated through comparisons of load–displacement, torque-rotation curves, and full-field displacement maps between experimental and numerical analyses
Benchtop machining of self-standing alumina doughs for low-number fabrication and prototyping
No full textCold isostatic pressing, gel casting, and protein coagulation are the most common techniques to produce green bodies prior to computer numerical control (CNC)-based machining for the near-net-scale shaping of ceramics. These methods typically involve various additives and entail several steps to create a green body that is capable of withstanding machining forces. Here, utilizing a single additive, we first introduced a facile benchtop method to generate self-standing, malleable doughs of alumina in under 2 min. We then optimized the parameters of CNC machining to obtain surfaces with minimum surface roughness and produced custom-sized crucibles as a showcase for low-number production. To consolidate a dough from highly loaded suspensions of alumina, we employed a poly(ethylene glycol)-grafted random copolymer of acrylic acid and N-[3-(dimethylamino)propyl]methacrylamide at 0.75 wt % with respect to the weight of alumina powder. We surveyed machining parameters with spindle speeds ranging from 5000 to 30000 rpm and cutting speeds from 1000 to 1800 mm/min using 1 and 2 mm tool sizes. The highest surface quality, characterized by the minimal surface roughness as evaluated by profilometry, was achieved at a spindle speed of 20000 rpm and a cutting speed of 1200 mm/min with a 1 mm tool and at a spindle speed of 15000 rpm and a cutting speed of 1800 mm/min with a 2 mm tool. Upon sintering, the hardness of the machined samples was measured to be 15.16 ± 1.15 GPa. Additionally, we demonstrated the recycling of alumina (up to 30 wt % of alumina content) sourced from intentionally broken parts in the green state. The recycling scheme contributes to the lowering of the use of resources and emphasizes the possibility of a greener future for ceramic production on a broader scale. Overall, this cost-effective and easy-to-implement methodology starts at the materials formulation level and parametrization of the machining paves the way for immediate industrial adaptation
Gamma, charged particle and neutron shielding properties of polyethylene based thermoplastic compounds doped with titanate and zirconate additives
No full textKnowing how efficient radiation shielding materials are being essential for a variety of uses, including nuclear power plants and medical imaging. This study examined the gamma and neutron shielding capabilities of thermoplastic polymers based on polyethylene and doped with titanate and zirconate additions. Over an energy range of 53.16–383.85 keV, experimental measurements were made of the compound's mass attenuation coefficients (MAC), mean free pathways (MFP), half-value layers (HVL), and effective atomic numbers (Zeff). Additionally, a Am241-Be fast neutron source with an activity of 10 mCi was used to measure neutron equivalent dose rates. The exposure buildup factor (EBF) and the neutron removal cross section (ΣR) were calculated theoretically. Assessment of a compound's appropriateness for nuclear security applications with an emphasis on its alpha and proton shielding capabilities. The neutron equivalent dose rate for the PP/PE was 9.4722%, while it was 37.9283% for the PP/PE/Zirconate. Based on gamma and neutron shielding efficiencies, the observed results suggest that polyethylene based thermoplastic compounds containing zirconate could be viable options for mask materials used in radiotherapy
Cavitating flow morphology determination in cavitation-on-a-chip devices based on local real-time pressure measurements
No full textThis study presents a practical approach for the characterization and control of hydrodynamic cavitation (HC) behavior in microfluidic devices by utilizing real-time static pressure measurements. Two geometrically identical micro-orifice devices were specifically designed for this purpose. Pressure measurement locations were strategically positioned along the embedded microchannel in both devices. These locations were determined as a function of the hydraulic diameter of the microchannel. Pressure measurements were simultaneously made with high-speed imaging. Particular attention was directed to the prediction and monitoring of cavitation inception, cavitating flow patterns, and cavitation development. Thus, the dynamic and complex nature of hydrodynamic cavitation in microdomains could be captured by local pressure variations along the microchannel walls. According to the results, cavitation inception and subsequent formation of twin sheet cavities could be detected by changes in local pressure values. Moreover, the analysis of local pressure variations could be employed to predict the length of sheet cavities. The findings of this study offer valuable guidelines for designing microfluidic systems involving hydrodynamic cavitation. Moreover, this study proves the potential of local wall pressure measurements as a stand-alone practical approach, which will reduce reliance on high-speed visualization. It could thus enhance the affordability and accessibility of HC-on-a-chip platforms for emerging applications, including biomedical engineering, wastewater treatment, and 2D material exfoliation
FlyVISTA, an integrated machine learning platform for deep phenotyping of sleep in Drosophila
No full textThere is great interest in using genetically tractable organisms such as Drosophila to gain insights into the regulation and function of sleep. However, sleep phenotyping in Drosophila has largely relied on simple measures of locomotor inactivity. Here, we present FlyVISTA, a machine learning platform to perform deep phenotyping of sleep in flies. This platform comprises a high-resolution closed-loop video imaging system, coupled with a deep learning network to annotate 35 body parts, and a computational pipeline to extract behaviors from high-dimensional data. FlyVISTA reveals the distinct spatiotemporal dynamics of sleep and wake-associated microbehaviors at baseline, following administration of the sleep-inducing drug gaboxadol, and with dorsal fan-shaped body drivers. We identify a microbehavior ("haltere switch") exclusively seen during quiescence that indicates a deeper sleep stage. These results enable the rigorous analysis of sleep in Drosophila and set the stage for computational analyses of microbehaviors in quiescent animals
Do they dislike us as much as we think? Positive contact as a potential rectifier of meta-attitude inaccuracy in conflictual intergroup settings
No full textIntergroup meta-attitude inaccuracy—the extent to which perceptions of outgroup views towards the ingroup diverge from what outgroup members actually think—fuels intergroup hostility, yet research on its precursors is scarce. Through four correlational studies, we examined whether and how intergroup contact predicts meta-attitude (in)accuracy in three conflict contexts: Black–White British in the United Kingdom (UK), Turks–Kurds in Turkey, and Catholics–Protestants in Northern Ireland. Regardless of context or status, all groups perceived themselves to be evaluated more negatively by the outgroup than they really were. Positive contact predicted increased meta-attitude accuracy (through increased shared reality) which was, in turn, associated with more positive outgroup attitudes. The role of negative contact and affective mediators (such as intergroup anxiety and fear) was not consistent and depended on group and context. The use of positive intergroup contact as a potential rectifier of overestimated negative meta-attitudes in conflict contexts is discussed