Loss Mechanisms Research Articles

Synthesis of hierarchical carbon Nanofibers-CoNi/C composites for enhanced microwave absorption efficiency

Developing lightweight, highly absorption and broadband microwave absorbents to combat severe electromagnetic radiation pollution poses a significant challenge. In this study, we designed a novel chain-like CNFs-CoNi/C nanocomposite by in-situ growth of bimetallic MOFs on the CNFs followed by calcination. The resulting CoNi/C composite with hollow structure was uniformly distributed along the 1D CNFs. The unique porous structure and heterogeneous interface derived from MOFs facilitated efficient scattering and multiple reflections of microwaves. By harnessing interfacial polarization loss, dipole polarization loss, and conduction loss mechanisms synergistically, the chain-shaped porous multi-stage CNFs-CoNi/C composite exhibited exceptional microwave absorption performance at a filling ratio of 10 %. It achieves a maximum reflection loss of −70 dB and an absorption bandwidth (EAB) for RL ≤ -10 exceeding 4.82 GHz with a corresponding thickness as low as 1.25 mm. This study introduced a lightweight and highly absorptive material that offers valuable insights into developing high-performance electromagnetic wave absorbing materials through organic composite comprising MOF and carbon materials.

Enhancing mechanical properties of concrete with 3D printed vascular networks via carbonation strengthening

Vascular systems offer promising potential for enabling self-recovery in cementitious materials, but their construction in three dimensions presents significant challenges. Our group has developed an embedded printing strategy allowing for the freeform construction of 3D hollow vascular channels, overcoming previous limitations. However, concerns persist regarding the weakening of mechanical properties caused by these vascular channels. In this study, we utilize carbon dioxide curing to reinforce the vascular wall, mitigating the mechanical loss associated with hollow vascular channel. We investigate the effect of carbonation on the vascular channel wall's morphology, composition, and microhardness along the radial direction to gain insight into its impact. Additionally, we analyze the influence of both vascular channels and carbonated vascular channels on intensity and cracking behaviors under various loading directions. The findings from this investigation provide essential insights for the design and optimization of vascular networks in concrete structures.

DNE-YOLO: A method for apple fruit detection in Diverse Natural Environments

The apple industry, recognized as a pivotal sector in agriculture, increasingly emphasizes the mechanization and intelligent advancement of picking technology. This study innovatively applies a mist simulation algorithm to apple image generation, constructing a dataset of apple images under mixed sunny, cloudy, drizzling and foggy weather conditions called DNE-APPLE. It introduces a lightweight and efficient target detection network called DNE-YOLO. Building upon the YOLOv8 base model, DNE-YOLO incorporates the CBAM attention mechanism and CARAFE up-sampling operator to enhance the focus on apples. Additionally, it utilizes GSConv and the dynamic non-monotonic focusing mechanism loss function WIOU to reduce model parameters and decrease reliance on dataset quality. Extensive experimental results underscore the efficacy of the DNE-YOLO model, which achieves a detection accuracy (precision) of 90.7%, a recall of 88.9%, a mean accuracy (mAP50) of 94.3%, a computational complexity (GFLOPs) of 25.4G, and a parameter count of 10.46M across various environmentally diverse datasets. Compared to YOLOv8, it exhibits superior detection accuracy and robustness in sunny, drizzly, cloudy, and misty environments, making it especially suitable for practical applications such as apple picking for agricultural robots. The code for this model is open source at https://github.com/wuhaitao2178827/DNE-YOLO.

Mycobacteria that cause tuberculosis have retained ancestrally acquired genes for the biosynthesis of chemically diverse terpene nucleosides.

Mycobacterium tuberculosis (Mtb) releases the unusual terpene nucleoside 1-tuberculosinyladenosine (1-TbAd) to block lysosomal function and promote survival in human macrophages. Using conventional approaches, we found that genes Rv3377c and Rv3378c, but not Rv3376, were necessary for 1-TbAd biosynthesis. Here, we introduce linear models for mass spectrometry (limms) software as a next-generation lipidomics tool to study the essential functions of lipid biosynthetic enzymes on a whole-cell basis. Using limms, whole-cell lipid profiles deepened the phenotypic landscape of comparative mass spectrometry experiments and identified a large family of approximately 100 terpene nucleoside metabolites downstream of Rv3378c. We validated the identity of previously unknown adenine-, adenosine-, and lipid-modified tuberculosinol-containing molecules using synthetic chemistry and collisional mass spectrometry, including comprehensive profiling of bacterial lipids that fragment to adenine. We tracked terpene nucleoside genotypes and lipid phenotypes among Mycobacterium tuberculosis complex (MTC) species that did or did not evolve to productively infect either human or nonhuman mammals. Although 1-TbAd biosynthesis genes were thought to be restricted to the MTC, we identified the locus in unexpected species outside the MTC. Sequence analysis of the locus showed nucleotide usage characteristic of plasmids from plant-associated bacteria, clarifying the origin and timing of horizontal gene transfer to a pre-MTC progenitor. The data demonstrated correlation between high level terpene nucleoside biosynthesis and mycobacterial competence for human infection, and 2 mechanisms of 1-TbAd biosynthesis loss. Overall, the selective gain and evolutionary retention of tuberculosinyl metabolites in modern species that cause human TB suggest a role in human TB disease, and the newly discovered molecules represent candidate disease-specific biomarkers.

Influence of 3D Structural Design on the Electrochemical Performance of Aluminum Metal as Negative Electrode for Li-Ion Batteries.

Aluminum (Al) is one of the most promising active materials for producing next-generation negative electrodes for lithium (Li)-ion batteries. It features low density, high specific capacity, and low working potential, making it ideal for producing energy-dense cells. However, this material loses its electrochemical activity within 100 cycles, making it practically unusable. Several claims in the literature support the idea that a dual degradation mechanism is at play. First, the slow diffusion of Li in the Al matrix causes the electrochemical reactions to be partly irreversible, making the initial capacity of the cell drop. Second, the stress caused by cycling make the active material pulverize and lose activity. Recent work shows that shortening the diffusion path of Li by 3D structuring is an effective way to mitigate the first capacity loss mechanism, while alloying Al with other elements effectively mitigates the second one. In this work, we demonstrate that the benefits of 3D structuring and alloying are cumulative and that a mesh made of an Al-magnesium alloy performs better than both a pure Al foil and a foil of an Al-Mg alloy.

Deciphering Anion Exchange Membrane Water Electrolysis: A Distribution of Relaxation Times Approach

Anion exchange membrane water electrolysis (AEM-WE) is a promising method for hydrogen production, offering advantages over proton exchange membrane water electrolysis (PEM-WE), such as the use of nonprecious metal catalysts and perfluorosulfonic acid free membranes. Despite achieving impressive current densities, challenges in efficiency and stability remain. This study employs electrochemical impedance spectroscopy (EIS), the equivalent circuit model (ECM) and distribution of relaxation times (DRT) analysis to investigate AEM-WE cells. DRT analysis identifies and quantifies five loss mechanisms within the AEM-WE system, including hydrogen and oxygen evolution reactions and ionic transport losses. Long-term experiments reveal catalyst degradation and its impact on performance, providing insights for targeted optimisation. The findings enhance understanding of the electrochemical processes in AEM-WE, offering pathways to improve stability and efficiency.

Deciphering Anion Exchange Membrane Water Electrolysis: A Distribution of Relaxation Times Approach

Anion exchange membrane water electrolysis (AEM-WE) is a promising method for hydrogen production, offering advantages over proton exchange membrane water electrolysis (PEM-WE), such as the use of nonprecious metal catalysts and perfluorosulfonic acid free membranes. Despite achieving impressive current densities, challenges in efficiency and stability remain. This study employs electrochemical impedance spectroscopy (EIS), the equivalent circuit model (ECM) and distribution of relaxation times (DRT) analysis to investigate AEM-WE cells. DRT analysis identifies and quantifies five loss mechanisms within the AEM-WE system, including hydrogen and oxygen evolution reactions and ionic transport losses. Long-term experiments reveal catalyst degradation and its impact on performance, providing insights for targeted optimisation. The findings enhance understanding of the electrochemical processes in AEM-WE, offering pathways to improve stability and efficiency.

Risperidone accelerates bone loss in mice models of schizophrenia by inhibiting osteoblast autophagy

BackgroundRisperidone (RIS) is the first-line drug in the clinical treatment of schizophrenia, and long-term use may lead to bone loss and even osteoporosis. This study investigated whether the mechanism of RIS-induced bone loss is related to autophagy. MethodsThe schizophrenia mice were established with the administration of MK-801. Then, RIS were injected, or autophagy inducer rapamycin (RAPA) co-injected for 8 weeks. Cognitive performance was determined by the novel object recognition and Open field tests. Bone loss of schizophrenia mice were assessed using microCT, H&E staining, ALP staining, ARS staining and WB, respectively. Autophagy of schizophrenia mice were detected by immunofluorescence, transmission electron microscopy (TEM) and WB, respectively. In addition, osteogenic differentiation of MC3T3-E1 and BMSCs cells were assessed using H&E staining, ALP staining, ARS staining and WB, respectively. ResultsIn the present study, we found that RIS treatment can promote bone loss in schizophrenia mice and inhibit osteogenic differentiation of MC3T3-E1 and BMSCs cells. Interesting, the number of autophagosome and autophagy-related protein expression were decreased after RIS treatment. However, the bone loss and inhibition of osteogenic differentiation induced by RIS in schizophrenia mice were reversed by autophagy inducer RAPA. ConclusionRIS significantly increased bone loss and inhibited osteogenic differentiation in schizophrenia mice; the underlying mechanism entails suppressing osteoblast autophagy.

Pear pomace soluble dietary fiber suppresses fat deposition in high fat diet-fed mice by regulating the ADPN-AMPK/PPAR-α signaling pathway

This study was amied to explore the molecular mechanisms of the effect of pear pomace soluble dietary fiber (PP-SDF) on weight gain, fat deposition and regulation of lipid metabolism in obese mice. The PP-SDF can positively modulate the adverse effects of obesity. In this study, the PP-SDF extracted via microbial fermentation was investigated for its weight loss mechanism in high-fat diet induced obese mice. Soluble dietary fiber was also investigated for the enzymes related to fat metabolism and for intervention to reduce adipose inflammation related to obesity. Furthermore, AMPK and PPAR-α signaling pathway related to ADPN were investigated and the key enzymes in the pathways were measured. The results show that PP-SDF regulated obesity-related metabolic disorders by inhibiting obesity inflammation and by activating AMPK/PPAR-α signaling pathway, while ADPN was the key target for the regulation of these two pathways.

Designing Electronic Structures of Multiscale Helical Converters for Tailored Ultrabroad Electromagnetic Absorption

HighlightsThe energy conversion mechanism is thoroughly analyzed, with a detailed quantitative characterization of the dissipation capacities of polarization, conduction, and magnetic loss.Inspired by DNA transcription, atom and geometry configurations co-modulating multi-scale helical converters achieve the RLmin of −63.13 dB at 1.29 mm, and the maximum RCS reduction value reach 36.4 dB m2.Orbital coupling, spin and cross polarization synergize to realize a 6.08 GHz EAB, further expanding to ultrabroad electromagnetic wave absorption of 12.16 GHz through metamaterial design.

PTEN Deficiency Induced by Extracellular Vesicle miRNAs from Clonorchis sinensis Potentiates Cholangiocarcinoma Development by Inhibiting Ferroptosis.

The human phosphatase and tensin homolog (PTEN) is a tumor suppressor. A slight deficiency in PTEN might cause cancer susceptibility and progression. Infection by the liver fluke Clonorchis sinensis could lead to persistent loss of PTEN in cholangiocarcinoma. However, the mechanism of PTEN loss and its malignant effect on cholangiocarcinoma have not yet been elucidated. Extracellular vesicles secreted by Clonorchis sinensis (CS-EVs) are rich in microRNAs (miRNAs) and can mediate communication between hosts and parasites. Herein, we delved into the miRNAs present in CS-EVs, specifically those that potentially target PTEN and modulate the progression of cholangiocarcinoma via ferroptosis mechanisms. CS-EVs were extracted by differential ultra-centrifugation for high-throughput sequencing of miRNA. Lentiviral vectors were used to construct stably transfected cell lines. Erastin was used to construct ferroptosis induction models. Finally, 36 miRNAs were identified from CS-EVs. Among them, csi-miR-96-5p inhibited PTEN expression according to the predictions and dual luciferase assay. The CCK-8 assay, xenograft tumor assays and transwell assay showed that csi-miR-96-5p overexpression and PTEN knockout significantly increased the proliferation and migration of cholangiocarcinoma cells and co-transfection of PTEN significantly reversed the effect. In the presence of erastin, the cell proliferation and migration ability of the negative transfection control group were significantly impaired, although they did not significantly change with transfection of csi-miR-96-5p and PTEN knockout, indicating that they obtained ferroptosis resistance. Mechanistically, csi-miR-96-5p and PTEN knockout significantly inhibited ferroptosis through a decrease in ferrous ion (Fe2+) and malondialdehyde (MDA), and an increase in glutathione reductase (GSH), Solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4). In conclusion, loss of PTEN promoted the progression of cholangiocarcinoma via the ferroptosis pathway and csi-miR-96-5p delivered by CS-EVs may mediate this process.

Theory of Stimulated Brillouin Scattering in Fibers for Highly Multimode Excitations

Stimulated Brillouin scattering (SBS) is often an unwanted loss mechanism in both active and passive fibers. Highly multimode excitation of fibers has been proposed as a novel route toward efficient SBS suppression. Here, we develop a detailed, quantitative theory which confirms this proposal and elucidates the physical mechanisms involved. Starting from the vector optical and scalar acoustic equations, we derive appropriate nonlinear coupled mode equations for the signal and Stokes modal amplitudes and an analytical formula for the SBS (Stokes) gain with applicable approximations, such as the neglect of shear effects. This allows us to calculate the exponential growth rate of the Stokes power as a function of the distribution of power in a highly multimode signal. The peak value of the gain spectrum across the excited modes determines the SBS threshold—the maximum SBS-limited power that can be sent through the fiber. The theory shows that the peak SBS gain is greatly reduced by highly multimode excitation due to gain broadening and relatively weaker intermodal SBS gain. The inclusion of exact vector optical modes in the calculation is crucial in order to capture the incomplete intermodal coupling due to mismatch of polarization patterns of higher-order modes. We demonstrate that equal excitation of the 160 modes of a commercially available, highly multimode circular step index fiber raises the SBS threshold by a factor of 6.5 and find comparable suppression of SBS in similar fibers with a D-shaped cross section. Published by the American Physical Society 2024

3D framework MXene Ti3C2/g-C3N4/Fe3Si magneto-dielectric foam unveiling superior microwave absorption and thermal management performance

In conjunction with the swift advancement of detection technologies, the challenge persists in developing advanced stealth materials. The focus of this work is on the straightforward synthesis of a hybrid magneto-dielectric nanocomposite material composed of MXene Ti3C2/Fe3Si/g-C3N4 within a three-dimensional melamine foam framework, designed to deliver effective stealth capabilities. The high electrical conductivity and considerable permittivity of Ti3C2 have imposed limitations on its effectiveness in electromagnetic wave absorbers. In this context, the utilization of this compound in combination with substances like g-C3N4 and Fe3Si to fine-tune impedance matching and fully exploit the intrinsic properties is suggested. Furthermore, the distinctive 3D porous frameworks of the melamine foam, combined with the accordion-like structure of the MXene compound, extend and elongate paths for wave propagation to enhance energy dissipation. Through the activation of various loss mechanisms, it was possible to achieve a minimum reflection loss of −44.3 dB using a 1.5 mm thickness with an effective absorption bandwidth of 1.9 GHz. The enhancement of stealth performance was achieved through the combination of heterojunction interfaces among hybrid components and a 3D interconnected continuous path within the structure.

Discrete element simulation of ground collapse induced by buried sewage pipeline breakage and soil leakage

The rupture of buried sewage pipelines constitutes a primary triggering factor of ground collapse. To investigate the phenomenon of ground collapse resulting from buried sewage pipeline breakage and soil particle leakage, numerical simulations employing the discrete element method (DEM) are utilized. The study focuses on examining the ground collapse mechanisms in both dry and water-rich sand stratum scenarios. A positive correlation is identified between the particle loss rate (PLR) and the magnitude of ground collapse, and a microscopic analysis of the mechanism of particle loss is carried out to visualize the soil arching process. The entire collapse process shows that the formation and destruction of soil arching are clearly accompanied by the particle loss phenomena. Additionally, the computational fluid dynamics (CFD) module is incorporated into the DEM to investigate the collapse of water-rich sand stratum. Parametric studies involving the burial depth of the pipeline, water pressure, the defect radius of the pipeline breakage, and the defect shapes are comprehensively conducted. It is found that the water pressure is the primary factor influencing the PLR, which progressively increases with higher water pressure, larger radius of pipe defect, and shallower burial depth.

Quantum control of polariton emission in a microcavity-quantum well system under magnetic field

In this work, a quantum dissipative model is employed to investigate the influence of a perpendicular magnetic field on the photoluminescence (PL) spectrum of a quantum well embedded within a microcavity. This model incorporates both the exact electron-hole interaction within the semiconductor and the light-matter coupling between the fundamental photonic mode and the fermionic particles. The loss and pumping mechanisms are described using the quantum master equation, and the PL spectrum is determined via the quantum regression theorem. Our findings demonstrate that the magnetic field acts as a control mechanism in the polariton emission energy, the emission linewidth and the intensity distribution along the emission line. Finally, it is observed that the magnetic field can redistribute the density matrix occupations leading to modifications in the average number of polaritons in the system.

Targeting SHCBP1 Inhibits Tumor Progression by Restoring Ciliogenesis in Ductal Carcinoma

Abstract Primary cilia detect and transmit environmental signals into cells. Primary cilia are absent in a subset of ductal carcinomas characterized by distinctive biological activities, and recovery of cilia with normal functionality has been shown to have therapeutic potential in some cancer types. Therefore, elucidation of the underlying mechanism and clinical significance of ciliary loss in ductal carcinomas could help develop effective treatment strategies. Here, we identified a link between SHCBP1 and cilia in ductal carcinomas. Shcbp1 knockout in transgenic mice profoundly impeded tumor progression and metastasis, prolonging survival. Single-cell transcriptome analysis revealed a functional connection between SHCBP1 deficiency and increased tumor ciliogenesis. SHCBP1 ablation restored ciliogenesis in unciliated ductal carcinoma by promoting the proximity between the midbody remnant (MBR) and centrosome through enhanced Rab8 GTPase activity and Rab8GTP positioning within the MBR. Inhibition of tumor progression by SHCBP1 loss relied on the recovery of ciliogenesis. Analysis of a large cohort of patients with ductal carcinoma revealed a negative correlation between SHCBP1-induced ciliary loss and patient prognosis. Restoring ciliogenesis via SHCBP1 ablation elicited therapeutic effects in patient-derived xenograft models. Together, this study delineates that induction of MBR-centrosome proximity through SHCBP1-deficiency reactivates ciliogenesis, offering unique opportunities for the treatment of unciliated ductal carcinomas.

Association between maternal religious service attendance and pregnancy loss in the United States: a secondary analysis of the Future Families & Child Wellbeing Study.

Accumulating evidence suggests that spirituality and religiosity may be associated with improved health outcomes. However, few studies have examined maternal religiosity as a protective factor for perinatal outcomes. We explored the association between maternal religious attendance and pregnancy loss. Data were drawn from the Future Families & Child Wellbeing Study's first and second waves and medical records (n=1874). Religious attendance was a self-reported response to the question "About how often do you attend religious services?" Pregnancy loss was measured from responses to the second wave survey question, "Since focal child's birth, have you had any miscarriages/abortions/stillbirths?" Logistic regression estimated odds ratios (OR) and 95% confidence intervals (CI) for the association between maternal religious attendance frequency and pregnancy loss, overall and by race. Models were adjusted for sampling weights, religious preference, socioeconomic and behavioral factors. 8% (n=164) of mothers reported having a pregnancy loss. Of those with a pregnancy loss, 28% (n=46) attended services hardly ever and 20% (n=20) attended services once a week or more. Women who attended services more frequently had 58% increased odds of not experiencing a pregnancy loss (OR:1.58;95%CI:1.01,2.48) after adjusting for potential confounding. A post hoc analysis found no difference in pregnancy loss type or subsequent reproductive history based on attendance level. Results suggest that higher maternal religious attendance frequency may be a protective factor for pregnancy loss. Further research is needed to understand the association between maternal religious attendance and mechanisms for pregnancy loss.

Experimental and simulation study of energy loss mechanism of low pressure ratio radial turbine

Low-pressure ratio conditions are commonly encountered in radial turbines. When operating at low pressure ratio condition, a significant portion of the turbine energy loss occurs as residual velocity loss in the form of swirling flow at the outlet pipe. Typically, this energy can be recovered by the next stage turbine or reduced by the diffuser. However, there is a lack of experimental and simulation studies on the swirling flow at the outlet of turbines. The mechanism governing the changing pattern of swirling flow remains unclear, limiting the effective utilization and reduction of residual velocity loss. This study conducts theoretical and experimental research on turbine outlet swirling flow. Firstly, this paper introduces a novel two-dimensional hot-wire anemometry stepping mechanism for measuring swirling flow at a turbine outlet cross-section. Experimental results demonstrate that the proposed measurement method effectively captures the morphological changes of turbine outlet swirling flow. The results indicate a strong coupling relationship between axial and circumferential velocity. Subsequently, to elucidate the reasons for the coupling of velocity in two directions and the development of swirling flow in the outlet pipeline, simulations of turbine performance under different velocity ratio conditions were conducted. Results show that under a wide range of velocity ratios, not only does the direction of the turbine outlet swirling flow change, but it also leads to the swirl number exceeding the critical swirl ratio under high velocity ratio conditions, resulting in the formation of a central recirculation zone (CRZ) at the pipe outlet. The main cause of the strong coupling effect between velocities in two directions is attributed to the increased swirl intensity leading to enhanced adverse pressure gradients at the core of the vortex. Lastly, a model describing the variation of VGT turbine outlet swirling flow is established, indicating a linear relationship between the swirl number and the velocity ratio, with a steeper change as the pressure ratio decreases.

High-entropy TiVNbMoC3Tx MXene hybrid with balanced dielectric-magnetic loss for high-efficient electromagnetic wave absorption with environmental stability

With the advent of the 5G era, there is a growing demand for electromagnetic wave (EMW) absorbers that offer both efficient absorption and improved environmental stability. Transition metal carbides/carbonitrides (MXene), with their atomic-layered structures and high electrical conductivity, offer substantial potential for crafting efficient electromagnetic functional materials. Yet, enhancing the antioxidant capabilities and addressing the poor loss mechanisms of traditional MXene absorbers remain challenging tasks. In this context, a TiVNbMoC3Tx high-entropy MXene (HE-MXene) and its magnetic hybrids were synthesized for the first time. The unique multicomponent structure of high-entropy MXene reduces grain boundary formation, thereby slowing the progression of oxidation reactions. The incorporation of magnetic nanoparticles induces interface polarization loss or strong magnetic coupling, thereby enhancing EMW attenuation. These magnetic HE-MXene hybrids demonstrated a minimum reflection loss of −57.59 dB at a matching thickness of 1.46 mm and an effective absorption bandwidth (EAB) of 4.72 GHz at a thickness of 1.53 mm. Furthermore, the magnetic hybrids also exhibited outstanding oxidation and electrochemical corrosion resistance. This research provides valuable theoretical insights for the development of electromagnetic composites within high entropy (HE) systems, showcasing significant potential for long-term applications.

Membrane compaction in batch reverse osmosis operation and its impact on specific energy consumption

Reverse osmosis (RO) membrane water permeability is measured under cyclic pressure loading conditions corresponding to batch and semi-batch operation modes. Due to the viscoelasticity of the membrane support layer, compaction effects carry forward across multiple pressurization cycles, with the intracycle behavior stabilizing after a large number of cycles. The average membrane permeability of semi-batch RO systems is lower than that of batch RO, since semi-batch RO spends a larger fraction of its cycle time at higher pressures. The instantaneous permeability in batch RO decreases during the cycle as pressure is increased, but at a lower rate than the steady-state permeability variation with applied pressure. Therefore, the batch permeability values are lower at low pressures and higher at high pressures than the corresponding steady-state values. Since more water is recovered in the initial low-pressure stages of a multi-stage RO system, compaction increases the specific energy consumption of batch RO more than that of staged systems. Other loss mechanisms such as channel and minor pressure losses and high-pressure motor+pump efficiency variation with load further result in batch RO becoming energetically inferior to two- or three-stage RO, especially for low-salinity, high recovery applications.