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Singlet Oxygen's Potential Role as a Nonoxidative Facilitator of Disulfide S-S Bond Rotations

PHOTOCHEMISTRY AND PHOTOBIOLOGY 2023年第2期99卷 652-660页

作者： Turque, Oliver O'Connor, Ryan M. Greer, Alexander CUNY Dept Chem Brooklyn Coll New York NY 10017 USA CUNY PhD Program Biochem Grad Ctr New York NY 10017 USA CUNY PhD Program Chem Grad Ctr New York NY 10017 USA

The role of singlet oxygen potentially mediating increased conformational flexibility of a disulfide was investigated. Density functional theory (DFT) calculations indicate that the singlet oxygenation of 1,2-dimethyldisulfane produces a peroxy intermediate. This intermediate adopts a structure with a longer S-S bond distance and a more planar torsional angle theta (C-S-S-C) compared with the nonoxygenated 1,2-dimethyldisulfane The lengthened S-S bond enables a facile rotation about the torsional angle in the semicircle region 0 degrees < theta < 210 degrees, that is similar to 5 kcal mol(-1) lower in energy than the disulfane. The peroxy intermediate bears n(o) -> sigma(S-S )and no -> sigma(S-S* ) interactions that stabilize the S-O bond but destabilize the S-S bond, which contrasts with stabilizing ns -> sigma(S-S* ) hyperconjugative effects in the disulfane 5-5 bond. Subsequent departure of O-2 from the disulfane peroxy intermediate is reminiscent of peroxy intermediates which also expel O-2, yet facilitate cis-trans isomerizations of stilbenes, hexadienes, cyanines, and carotenes. "Non-oxidative" O-1(2) interactions with a variety of bond types are currently underappreciated. We hope to raise awareness of how these interactions can help elucidate the origins of molecular twisting.

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Overall biomass yield on multiple nutrient sources

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NPJ SYSTEMS BIOLOGY AND APPLICATIONS 2025年第1期11卷 1-11页

作者： Golan, Ohad Gampp, Olivia Eckert, Lina Sauer, Uwe Swiss Fed Inst Technol Inst Mol Syst Biol Zurich Switzerland Life Sci Zurich PhD Program Syst Biol Zurich Switzerland

Microorganisms primarily utilize nutrients to generate biomass and replicate. When a single nutrient source is available, the produced biomass typically increases linearly with the initial amount of that nutrient. This linear trend can be accurately predicted by "black box models", which conceptualize growth as a single chemical reaction, treating nutrients as substrates and biomass as a product. However, natural environments usually present multiple nutrient sources, prompting us to extend the black box framework to incorporate catabolism, anabolism, and biosynthesis of biomass precursors. This modification allows for the quantification of co-utilization effects among multiple nutrients on microbial biomass production. The extended model differentiates between different types of nutrients: non-degradable nutrients, which can only serve as a biomass precursor, and degradable nutrients, which can also be used as an energy source. We experimentally demonstrated using Escherichia coli that, in contrast to initial model predictions, different nutrients affect each other's utilization in a mutually dependent manner;i.e., for some combinations, the produced biomass was no longer proportional to the initial amounts of nutrients present. To account for these mutual effects within a black box framework, we phenomenologically introduced an interaction between the metabolic processes involved in utilizing the nutrient sources. This phenomenological model qualitatively captures the experimental observations and, unexpectedly, predicts that the total produced biomass is influenced not only by the combination of nutrient sources but also by their relative initial amounts - a prediction we subsequently validated experimentally. Moreover, the model identifies which metabolic processes - catabolism, anabolism, or precursor biosynthesis-is affected in each specific nutrient combination, offering insights into microbial metabolic coordination.

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A continuum of amorphous ices between low-density and high-density amorphous ice

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COMMUNICATIONS CHEMISTRY 2024年第1期7卷 36页

作者： Eltareb, Ali Lopez, Gustavo E. Giovambattista, Nicolas CUNY Dept Phys Brooklyn Coll Brooklyn NY 11210 USA CUNY PhD Program Phys Grad Ctr New York NY 10016 USA CUNY Dept Chem Lehman Coll Bronx NY 10468 USA CUNY PhD Program Chem Grad Ctr New York NY 10016 USA

Amorphous ices are usually classified as belonging to low-density or high-density amorphous ice (LDA and HDA) with densities rho LDA approximate to 0.94 g/cm3 and rho HDA approximate to 1.15-1.17 g/cm3. However, a recent experiment crushing hexagonal ice (ball-milling) produced a medium-density amorphous ice (MDA, rho MDA approximate to 1.06 g/cm3) adding complexity to our understanding of amorphous ice and the phase diagram of supercooled water. Motivated by the discovery of MDA, we perform computer simulations where amorphous ices are produced by isobaric cooling and isothermal compression/decompression. Our results show that, depending on the pressure employed, isobaric cooling can generate a continuum of amorphous ices with densities that expand in between those of LDA and HDA (briefly, intermediate amorphous ices, IA). In particular, the IA generated at P approximate to 125 MPa has a remarkably similar density and average structure as MDA, implying that MDA is not unique. Using the potential energy landscape formalism, we provide an intuitive qualitative understanding of the nature of LDA, HDA, and the IA generated at different pressures. In this view, LDA and HDA occupy specific and well-separated regions of the PEL;the IA prepared at P = 125 MPa is located in the intermediate region of the PEL that separates LDA and HDA. Recently, a medium-density amorphous ice (MDA) was synthesized via ball-milling of hexagonal ice, adding complexity to our understanding of the phase diagram of supercooled water and amorphous ice. Here, the authors use molecular dynamics simulations to show that, depending on the employed pressure, isobaric cooling can generate a continuum of amorphous ices with densities that expand in between those of low- and high-density amorphous ices, with some of these amorphous ices being remarkably similar to MDA.

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Influence Analysis of the Acoustic Radiation Characteristics of Circular Hole in Headphone Using Specific Flow Resistance 11

Influence Analysis of the Acoustic Radiation Characteristics...

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11th IEEE International Conference on Consumer Electronics - Taiwan (ICCE-Taiwan) - Empower of Innovative Consumer Technology

作者： Lei, Tzu-Hsuan Wu, Shu-Chien Lo, Kuang-Che Liu, Shu-Chi Liu, Yu-Cheng Feng Chia Univ PhD Program Mech & Aeronaut Engn Taichung Taiwan Feng Chia Univ Master Program Electroacoust Taichung Taiwan

ISBN: (纸本)9798350386851;9798350386844

The geometric dimensions of vent holes in headphone products are key to the impedance characteristics of sound wave propagation and, in turn, affect the low-frequency acoustic performance. However, qualitative and quantitative research on this topic is still insufficient. Therefore, we studied headphone rear chamber vent hole, with a diameter and depth of 1.0 mm and 2 mm, respectively. The acoustic specific airflow resistance of the vent hole was measured using a self-made system that consists of a differential pressure meter and a flow controller. Then, the results were input into the model for correction, to complete the verification between finite element simulation and measurements. The results showed that simulations corrected with the specific airflow resistance measurements of vent hole in the headphone chamber not only enhance the accuracy of low-frequency simulations, but also effectively reduce the error, with maximum discrepancy between simulation and measurement decreasing from 1.3% to 0.063%.

关键词： Specific Airflow Resistance Vent Holes Headphone Finite Element Method

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Behavioral Alterations in Mice Exposed to Manganese via Drinking Water: Effects of Sex and a Lipopolysaccharide Challenge

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JOURNAL OF APPLIED TOXICOLOGY 2025年第4期45卷 669-684页

作者： Ludwig, Helaina D. Carpenter, Jessica M. Filipov, Nikolay M. Univ Georgia Dept Physiol & Pharmacol Athens GA 30602 USA Univ Georgia Interdisciplinary Toxicol Program Athens GA 30602 USA Univ Georgia Neurosci PhD Program Athens GA 30602 USA

Manganese (Mn) is an essential and important metal;however, overexposures lead to adverse neurological outcomes. Nonoccupational Mn overexposure occurs primarily through consumption of Mn-contaminated drinking water (DW). Sex differences in terms of nervous and immune systems' responsiveness to excessive Mn in the DW are understudied. Thus, this study investigated behavioral and sex differences in response to Mn DW treatment (0.4 g Mn/L for up to 8 weeks) and a lipopolysaccharide (LPS) challenge of adult C57BL/6 mice with GFP-tagged monocytes/microglia. After 6 weeks, in motor function tests, Mn exposure resulted in decreased activity and gait deficits. In two different mood tests (open field test [OFT]/elevated zero maze), Mn-exposed mice exhibited decreased fear/anxiety-like behavior. Two weeks after behavioral assessment, when mice were challenged with LPS, circulating inflammatory cytokines, and acute phase proteins increased in both sexes. After 8 weeks of Mn exposure, liver and brain Mn levels were increased, but Mn alone did not affect circulating cytokines in either sex. Notably, Mn-exposed/LPS-challenged males had potentiated plasma cytokine output, whereas the reverse was seen in females. Males, but not females, continued to exhibit increased fearlessness (i.e., increased OFT center time), even when challenged with LPS. Overall, our results show that Mn DW exposure increases brain Mn levels and it leads to behavioral alterations in both sexes. However, males might be more susceptible to the effect of Mn on mood, and this effect is recalcitrant to an inflammagen challenge. Mn augmented post-LPS cytokine production only in males, further indicating that important Mn effects are sex-biased.

关键词： acute phase proteins behavioral deficits cytokines LPS manganese sex differences

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Potential energy landscape formalism for quantum molecular liquids

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COMMUNICATIONS CHEMISTRY 2024年第1期7卷 1-13页

作者： Eltareb, Ali Zhou, Yang Lopez, Gustavo E. Giovambattista, Nicolas CUNY Brooklyn Coll Dept Phys BROOKLYN NY 11210 USA CUNY Grad Ctr PhD Program Phys New York NY 10016 USA CUNY Lehman Coll Dept Chem BRONX NY 10468 USA CUNY Grad Ctr PhD Program Chem New York NY 10016 USA

The potential energy landscape (PEL) formalism is a powerful tool within statistical mechanics to study the thermodynamic properties of classical low-temperature liquids and glasses. Recently, the PEL formalism has been extended to liquids/glasses that obey quantum mechanics, but applications have been limited to atomistic model liquids. In this work, we extend the PEL formalism to liquid/glassy water using path-integral molecular dynamics (PIMD) simulations, where nuclear quantum effects (NQE) are included. Our PIMD simulations, based on the q-TIP4P/F water model, show that the PEL of quantum water is both Gaussian and anharmonic. Importantly, the ring-polymers associated to the O/H atoms in the PIMD simulations, collapse at the local minima of the PEL (inherent structures, IS) for both liquid and glassy states. This allows us to calculate, analytically, the IS vibrational density of states (IS-VDOS) of the ring-polymer system using the IS-VDOS of classical water (obtained from classical MD simulations). The role of NQE on the structural properties of liquid/glassy water at various pressures are discussed in detail. Overall, our results demonstrate that the PEL formalism can effectively describe the behavior of molecular liquids at low temperatures and in the glass states, regardless of whether the liquid/glass obeys classical or quantum mechanics.

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Research On Three-Dimensional Measurement and Analysis of Spatial Sound Field 11

Research On Three-Dimensional Measurement and Analysis of Sp...

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11th IEEE International Conference on Consumer Electronics - Taiwan (ICCE-Taiwan) - Empower of Innovative Consumer Technology

作者： Ting, Po-Chun Liu, Yu-Cheng Feng Chia Univ PhD Program Mech & Aeronaut Engn Taichung Taiwan Feng Chia Univ Master Program Electroacoust Taichung Taiwan

ISBN: (纸本)9798350386851;9798350386844

The aim of this study is to propose innovative three-dimensional channel-based and scene-based measurement techniques for spatial sound fields, based on two-dimensional measurement and analysis, which can be used for measurement and analysis of important acoustic parameters in concert halls with more than 1,000 seats. The results were compared with actual reverberation time 60 (RT60) and early decay time (EDT) measurements obtained on site in 2006, with differences between the methods proposed in this study and on-site measurements ranging from 0.2 s similar to 0.4 s. Scene-based results were closest, with an average error of only 0.027 s. The error decreased as the frequency increased, reaching a minimum of 0.004 s. In addition, scene-based measurement not only simplifies the complex and tedious measurement processes of the past, but also produces more diverse spatial parameters for a comprehensive understanding of the acoustic characteristics of a space, which designers can quickly grasp and which can be used as references for optimization and improvement.

关键词： Three-dimensional spatial sound field measurement concert hall scene-based RT60

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Passive Cancellation Method for Reduction of Common-Mode Noise Currents

IEEE LETTERS ON ELECTROMAGNETIC COMPATIBILITY PRACTICE AND A...

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IEEE LETTERS ON ELECTROMAGNETIC COMPATIBILITY PRACTICE AND APPLICATIONS 2024年第4期6卷 149-154页

作者： Yau, Yeu-Torng Natl Chin Yi Univ Technol Dept PhD Program Prospective Technol Elect Engn & Comp Sci Taichung Taiwan

To meet the requirements of electromagnetic interference (EMI) certification, ac-dc converters always require a common-mode (CM) filter to limit the amount of EMI emissions transferred to the power grid. However, CM filters based on the well-known LC low-pass filter are usually bulky and costly. Many solutions to this problem have been proposed based on active filter technologies, which have the major drawback of requiring the use of current detectors, active circuits, and auxiliary power supplies. Therefore, a passive CM current cancellation method is proposed that is composed entirely of passive components and has the advantages of cost and system reliability. Compared with conventional passive LC filters, the number of magnetic components is the same, and only one additional winding is required. Previous studies only presented an ideal model without any related derivation, and the impact of any nonlinear components was not mentioned. In this letter, a further derivation of the nonlinear model is provided, and a comparison of the differences based on different characteristics of inductors is conducted to improve the circuit design.

关键词： Inductors Electromagnetic interference Noise Low-pass filters Insertion loss Inductance Capacitors Cancellation common-mode (CM) choke CM noise electromagnetic interference (EMI)

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Distinctive lipidomic responses induced by polystyrene micro- and nano-plastics in zebrafish liver cells

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AQUATIC TOXICOLOGY 2025年 281卷 107291页

作者： Wang, Tiantian Amoros, Miquel Perello Llao, Gemma Lopez Porte, Cinta IDAEA CSIC Environm Chem Dept C Jordi Girona 18-26 Barcelona 08034 Spain Univ Barcelona PhD Program Aquaculture Barcelona Spain

Despite growing awareness of the size-dependent toxicity caused by micro- and nano-plastics (MNPs) in fish, the modulation of the liver lipidome as a function of particle size has not been thoroughly investigated. This study explores the subcellular and molecular responses induced by polystyrene microplastics (MPs, 1 mu m) and nanoplastics (NPs, 52 nm) in zebrafish liver (ZFL) cells, with a focus on the modulation of the cell's lipidome and gene expression profiles. Both particle sizes are readily internalized by ZFL cells;however, NPs had a more pronounced impact compared to MPs. Lipidomic analysis revealed that MPs decreased polyunsaturated phospholipids, while NPs increased ether-linked phosphatidylcholines (PC-Ps/PC-Os). Gene expression analysis showed that high concentrations of MPs down-regulated the expression of fatty acid synthesis related genes, and significantly downregulated the microsomal triglyceride transfer protein (mtp) gene, indicating a perturbation in lipid storage metabolism, which was not observed for NP exposure. In contrast, NPs induced a dose-dependent accumulation of lipids, suggesting increased lipid droplet formation and an activation of ceramide-mediated apoptosis pathway. These findings provide new insights into the molecular mechanisms of MNP toxicity and emphasize the importance of considering particle size when assessing environmental and health risks. Furthermore, this study highlights the potential of lipidomics for elucidating the mechanisms underlying MNP toxicity, prompting further research into of the long-term consequences of exposure.

关键词： Toxicity mechanisms Lipidomics Gene expression MNPs Size

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Colorectal Polyp Detection and Comparative Evaluation Based on Deep Learning Approaches

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IEEE ACCESS 2023年 11卷 135074-135089页

作者： Chen, Yao-Tien Ahmad, Nisar Ming Chi Univ Technol Int PhD Program Innovat Technol Biomed Engn & Med New Taipei City 243303 Taiwan

Colorectal cancer has been one of the leading causes of mortality over the past decade, and colorectal polyps are the leading cause of this disease. Conventional polyp detection techniques are insufficient for proper detection;thus, an efficient detection method is indispensable. In this study, we collected colorectal images from a hospital in Taiwan, annotated the ground truth of polyp locations, and integrated them with a public dataset to create a colonoscopy dataset. Data augmentation techniques are further used to increase the training dataset's diversity to improve the models' detection performance. By developing the comparison system based on the recent state-of-the-art methods (i.e., FasterRCNN, SSD, YOLOv3, and YOLOv4), we compared the measurement metrics and statistically analyzed the performance of the models to identify the significant statistical difference in models' performance. Moreover, we developed and integrated an error handling mechanism with each model to discard the false and null predictions. Finally, our model comparison system selects and proposes the best performing deep learning model to detect and classify colorectal polyps. We expect that the proposed model will accurately locate and classify different types of polyps. Eventually, this approach will ensure a valuable medical aid model.

关键词： Colorectal cancer (CRC) colorectal polyps polyp detection deep learning data augmentation error handling

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