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We study the performance of a quantum Otto heat engine with two spins coupled by a Heisenberg interaction, taking into account not only the mean values of work and efficiency but also their fluctuations. We first show that, for this system, the output work and its fluctuations are directly related to the magnetization and magnetic susceptibility of the system at equilibrium with either heat bath. We analyze the regions where the work extraction can be done with low relative fluctuation for a given range of temperatures, while still achieving an efficiency higher than that of a single spin system heat engine. In particular, we find that, due to the presence of "idle" levels, an increase in the interspin coupling can either increase or decrease fluctuations, depending on the other parameters. In all cases, however, we find that the relative fluctuations in work or efficiency remain large, implying that this microscopic engine is not very reliable as a source of work.
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http://dx.doi.org/10.1103/PhysRevE.109.064129 | DOI Listing |
J Cardiovasc Electrophysiol
September 2025
Department of Internal Medicine, Division of Cardiology, American University of Beirut Medical Center, Beirut, Lebanon.
Environ Monit Assess
September 2025
School of Chemical Engineering, Universiti Sains Malaysia, Engineering Campus, 14300, Nibong Tebal, Penang, Malaysia.
Ciprofloxacin (CIP), a widely used fluoroquinolone antibiotic, has become a significant contaminant in aquatic environments due to its extensive use and incomplete metabolism. This review comprehensively analyses CIP pollution, including its sources, environmental and health impacts, and removal strategies. Chemical methods such as advanced oxidation processes and physical techniques like adsorption are evaluated for their efficiency in CIP removal.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
September 2025
Department of Dyes and Chemical Engineering, Bangladesh University of Textiles, Dhaka, Bangladesh.
This study quantitatively evaluated the adsorption performance of natural bentonite for removing three dye classes-cationic (Basic dye: BEZACRYL RED GRL), anionic (Reactive dye: AVITERA LIGHT RED SE), and non-ionic (Disperse dye: BEMACRON BLUE HP3R) from synthetic textile wastewater. Batch adsorption experiments were conducted under varying conditions of contact time (15-90 min), adsorbent dosage (20-60 g L⁻), pH (4 and 12), and temperature (25-100 °C), with dye concentrations quantified by UV-Vis spectroscopy. At a contact time of 30 min and room temperature (25 °C), maximum removal efficiencies reached 99.
View Article and Find Full Text PDFBiotechnol Lett
September 2025
Department of Chemical Engineering, Hongik University, Sangsu-dong, Mapo-gu, Seoul, 04066, Republic of Korea.
The cell surface display system employs carrier proteins to present target proteins on the outer membrane of cells. This system enables functional proteins to be exposed on the exterior of living cells without cell lysis, allowing direct interaction with the surrounding environment. A major limitation of conventional approaches is the difficulty in displaying large-sized enzymes or antibodies, despite their critical roles in applications requiring functional domains that must remain intact, such as catalytic or antigen-binding sites.
View Article and Find Full Text PDFNat Biotechnol
September 2025
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, USA.
Antibody-drug conjugates (ADCs) are effective targeted therapeutics but are limited in their ability to incorporate less-potent payloads, varied drug mechanisms of action, different drug release mechanisms and tunable drug-to-antibody ratios. Here we introduce a technology to overcome these limitations called 'antibody-bottlebrush prodrug conjugates' (ABCs). An ABC consists of an IgG1 monoclonal antibody covalently conjugated to the terminus of a compact bivalent bottlebrush prodrug that has payloads bound through cleavable linkers and polyethylene glycol branches.
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