Chemistry and radiative shielding in star forming galactic disks

To understand the conditions under which dense, molecular gas is able to form within a galaxy, we post-process a series of three-dimensional galactic-disk-scale simulations with ray-tracing based radiative transfer and chemical network integration to compute the equilibrium chemical and thermal state of the gas. In performing these simulations we vary a number of parameters, such as the ISRF strength, vertical scale height of stellar sources, cosmic ray flux, to gauge the sensitivity of our results to these variations. Self-shielding permits significant molecular hydrogen (H2) abundances in dense filaments around the disk midplane, accounting for approximately ~10-15% of the total gas mass. Significant CO fractions only form in the densest, n>~10^3 cm^-3, gas where a combination of dust, H2, and self-shielding attenuate the FUV background. We additionally compare these ray-tracing based solutions to photochemistry with complementary models where photo-shielding is accounted for with locally computed prescriptions. With some exceptions, these local models for the radiative shielding length perform reasonably well at reproducing the distribution and amount of molecular gas as compared with a detailed, global ray tracing calculation. Specifically, an approach based on the Jeans Length with a T=40K temperature cap performs the best in regards to a number of different quantitative measures based on the H2 and CO abundances.Comment: 21 Pages, 15 figures. Submitted to MNRAS. Comments welcom

Green workspace and urban health: exploring the impacts of industrial robotics in pollution emissions and public health

IntroductionThis study addresses a critical gap in understanding how technological advancements, specifically industrial robots, influence urban pollution emissions and public health. The rapid evolution of technology and changing working conditions significantly affect these areas, yet research has not extensively explored this domain.MethodsUtilizing 2018 China Labor-force Dynamic Survey (CLDS) dataset, this study examines the impact of industrial robots on public health. An analytical framework is employed to assess the correlation between the adoption of eco-friendly industrial robots and improvements in worker health, attributed to the reduction of pollution emissions.ResultsThe findings reveal that the adoption of industrial robots significantly enhance both public physical and mental health. This study also identifies potential demographic heterogeneity in the effects of industrial robots. The benefits are more pronounced among non-insured manual female workers who are older, have lower education levels, and hold rural hukou. These benefits are closely linked to improvements in the quality of the production environment and reductions in pollution emissions at both macro and micro levels.DiscussionThe study underscores the significant potential of industrial robots to positively impact urban health, advocating for strategies that promote the development of safer, greener environments

FGF22 deletion causes hidden hearing loss by affecting the function of inner hair cell ribbon synapses

Ribbon synapses are important structures in transmitting auditory signals from the inner hair cells (IHCs) to their corresponding spiral ganglion neurons (SGNs). Over the last few decades, deafness has been primarily attributed to the deterioration of cochlear hair cells rather than ribbon synapses. Hearing dysfunction that cannot be detected by the hearing threshold is defined as hidden hearing loss (HHL). The relationship between ribbon synapses and FGF22 deletion remains unknown. In this study, we used a 6-week-old FGF22 knockout mice model (Fgf22–/–) and mainly focused on alteration in ribbon synapses by applying the auditory brainstem response (ABR) test, the immunofluorescence staining, the patch-clamp recording, and quantitative real-time PCR. In Fgf22–/– mice, we found the decreased amplitude of ABR wave I, the reduced vesicles of ribbon synapses, and the decreased efficiency of exocytosis, which was suggested by a decrease in the capacitance change. Quantitative real-time PCR revealed that Fgf22–/– led to dysfunction in ribbon synapses by downregulating SNAP-25 and Gipc3 and upregulating MEF2D expression, which was important for the maintenance of ribbon synapses’ function. Our research concluded that FGF22 deletion caused HHL by affecting the function of IHC ribbon synapses and may offer a novel therapeutic target to meet an ever-growing demand for deafness treatment

A role for tunneling nanotubes in virus spread

Tunneling nanotubes (TNTs) are actin-rich intercellular conduits that mediate distant cell-to-cell communication and enable the transfer of various cargos, including proteins, organelles, and virions. They play vital roles in both physiological and pathological processes. In this review, we focus on TNTs in different types of viruses, including retroviruses such as HIV, HTLV, influenza A, herpesvirus, paramyxovirus, alphavirus and SARS-CoV-2. We summarize the viral proteins responsible for inducing TNT formation and explore how these virus-induced TNTs facilitate intercellular communication, thereby promoting viral spread. Furthermore, we highlight other virus infections that can induce TNT-like structures, facilitating the dissemination of viruses. Moreover, TNTs promote intercellular spread of certain viruses even in the presence of neutralizing antibodies and antiviral drugs, posing significant challenges in combating viral infections. Understanding the mechanisms underlying viral spread via TNTs provides valuable insights into potential drug targets and contributes to the development of effective therapies for viral infections

Chemistry and radiative shielding in star-forming galactic discs

To understand the conditions under which dense, molecular gas is able to form within a galaxy, we post-process a series of three-dimensional galactic-disc-scale simulations with ray-tracingbased radiative transfer and chemical network integration to compute the equilibrium chemical and thermal state of the gas. In performing these simulations, we vary a number of parameters, such as the interstellar radiation field strength, vertical scaleheight of stellar sources, and cosmic ray flux, to gauge the sensitivity of our results to these variations. Self-shielding permits significant molecular hydrogen (H2) abundances in dense filaments around the disc mid-plane, accounting for approximately~10-15 per cent of the total gasmass. SignificantCO fractions only form in the densest, nH ≳ 103 cm-3, gas where a combination of dust, H2, and self-shielding attenuates the far-ultraviolet background. We additionally compare these raytracing- based solutions to photochemistry with complementary models where photoshielding is accounted forwith locally computed prescriptions.With some exceptions, these local models for the radiative shielding length perform reasonably well at reproducing the distribution and amount of molecular gas as compared with a detailed, global ray-tracing calculation. Specifically, an approach based on the Jeans length with a T = 40K temperature cap performs the best in regard to a number of different quantitative measures based on the H2 and CO abundancesRIK, MRK, and CFM acknowledge support from NASA ATP grant NNX13AB84G. CFM and RIK acknowledge support from NSF grant AST-1211729. RIK acknowledges support from the US Department of Energy at the Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344

Heterogeneous flow in interstellar medium and star formation

Thesis (Ph. D.)--University of Rochester. Department of Physics and Astronomy, 2014.Almost all interstellar objects contain inherent inhomogeneity. The inhomogeneity can manifest in many different ways, such as the uneven matter distribution in a molecular cloud, or the tangled magnetic field distribution in a Bok globule. The dynamics of interstellar objects is thus often governed by the interaction between astrophysical flows or shocks such as supernova blast waves with inhomogeneous objects. We categorize such interactions as “heterogeneous flows” in general since many of their behaviors can be attributed to the heterogeneous nature of the underlying objects. At the computational physics group of the University of Rochester, we develop the highly sophisticated numerical tool AstroBEAR to study the physics of heterogeneous flows. One such problem is the heat conduction through interfaces between hot and cold magnetized plasmas. Through simulations, we find a simple mathematical relation for the rate of heat conduction as a function of the initial ratio of ordered to tangled field across the interface. The results can be applied to astrophysical objects such as magnetized wind blown bubbles (WBB) around evolved stars. The second problem involves the interaction between shocks and magnetized clumps. Using AstroBEAR, we consider the realistic circumstance in which the field is completely self-contained within the clumps. We find that the clump and magnetic evolution are sensitive to the fraction of magnetic field aligned with versus perpendicular to the shock normal. The relative strength of magnetic pressure and tension in the different field configurations allows us to analytically understand the different cases of postshock evolution. Interstellar heterogeneous flows can also lead to star formation. Based on the shock clump interaction model, star formation can be triggered by compression from wind or supernova driven shock waves that sweep over molecular clouds. This mechanism has been proposed as an explanation for short lived radioactive isotopes (SLRI) in the Solar System. Using AstroBEAR, we for the first time track the long term evolution of the triggering of a 1M⊙ cloud. We also demonstrate that through initial rotation, a circumstellar disk can be formed around such a triggering formed star. Recent progressions in the field of plasma physics, laser technology and instrumentation have led to lab platforms that are scalable to astrophysical objects. These platforms are ideal environments to study the heterogeneous flows directly. An important difference between the astrophysical objects and the lab platform is that the latter involves non-negligible resistivity. We introduce AstroBEAR simulations that investigate the magnetized shock-clump interaction problem under resistive MHD, and answer a crucial question regarding the lab design: in resistive MHD, under what conditions do the shocked behavior of a magnetized clump differ from a non-magnetized one? We find that for Rm ≤ 100, it is impossible to distinguish the two, while for Rm ≥ 1000, the resistive MHD has similar morphological evolution as the ideal MHD. These numerical studies provide theoretical foundation for the study of heterogeneous flows, and give direct guidance towards observations and lab astrophysics designs

Condition Monitoring of Rolling Bearing Based on Multi-Order FRFT and SSA-DBN

Owing to the symmetry of the rolling bearing structure and the rotating operation mode, the rolling bearing works in a complex environment. It is very easy to be submerged by noise and misdiagnosis. For the non-stationary signal in variable speed state, this paper presents a condition monitoring method based on deep belief network (DBN) optimized by multi-order fractional Fourier transform (FRFT) and sparrow search algorithm (SSA). Firstly, the fractional Fourier transform based on curve feature segmentation is used to filter the fault vibration signal and extract the fault feature frequency. Then, the fault features are input into the SSA-DBN model for training, and the bearing fault features are classified, identified, and diagnosed. Finally, the rotating machinery fault simulator in the laboratory of Ottawa University is taken as the practical application object to verify the effectiveness of the method. The experimental results show that the proposed method has higher recognition accuracy and stronger stability

Failure Of Hearing Acquisition in Mice With Reduced Expression of Connexin 26 Correlates With the Abnormal Phasing of Apoptosis Relative to Autophagy and Defective ATP-Dependent Ca2+ Signaling in Kölliker’s Organ

Mutations in the GJB2 gene that encodes connexin 26 (Cx26) are the predominant cause of prelingual hereditary deafness, and the most frequently encountered variants cause complete loss of protein function. To investigate how Cx26 deficiency induces deafness, we examined the levels of apoptosis and autophagy in Gjb2loxP/loxP; ROSA26CreER mice injected with tamoxifen on the day of birth. After weaning, these mice exhibited severe hearing impairment and reduced Cx26 expression in the cochlear duct. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive cells were observed in apical, middle, and basal turns of Kölliker’s organ at postnatal (P) day 1 (P1), associated with increased expression levels of cleaved caspase 3, but decreased levels of autophagy-related proteins LC3-II, P62, and Beclin1. In Kölliker’s organ cells with decreased Cx26 expression, we also found significantly reduced levels of intracellular ATP and hampered Ca2+ responses evoked by extracellular ATP application. These results offer novel insight into the mechanisms that prevent hearing acquisition in mouse models of non-syndromic hearing impairment due to Cx26 loss of function

Extracellular vesicles derived from HuMSCs alleviate daunorubicin-induced cardiac microvascular injury via miR-186-5p/PARP9/STAT1 signal pathway

Introduction: It is essential to acknowledge that the cardiovascular toxicity associated with anthracycline drugs can be partially attributed to the damage inflicted on blood vessels and endothelial cells. Extracellular vesicles (EVs) derived from mesenchymal stem cells (MSCs) have the potential to repair cellular processes and promote tissue regeneration through the transfer of signaling molecules such as miRNAs. In the present study, we investigated the effects of MSC-EVs on daunorubicin (DNR)-damaged human cardiac microvascular endothelial cells (HCMEC) and developing blood vessels of Chicken Chorioallantoic Membrane (CAM) in vivo. Materials and methods: We constructed in vitro and in vivo models of DNR-damaged endothelial cells and developing blood vessel. Scratch wound assays, EdU assays, tube formation assays, and SA-β-Gal staining were used to evaluate the effects of MSC-EVs on cell migration, proliferation, angiogenesis capacity and cell senescence. Blood vessel area was used to assess the effects of MSC-EVs on CAM vasculature. RT-qPCR was used to detect the mRNA expression levels of inflammatory molecules. RNA sequencing was employed to compare differential gene expression and downstream regulatory mechanisms. RNA interference experiments and miRNA mimic overexpression experiments were used to validate the regulatory effects of target genes and downstream signaling pathways. Results: We found that MSC-EVs improved the migration, proliferation, and angiogenesis of HCMEC, while also alleviating cellular senescence. The angiogenic effect on the developing blood vessels was confirmed in vivo. We identified that MSC-EVs downregulated the expression of PARP9, thereby inhibiting the STAT1/pSTAT1 signaling pathway. This downregulation effect is likely mediated by the transfer of miR-186-5p from MSC-EVs to HCMEC. Overexpression of miR-186-5p in DNR-damaged HCMEC also exhibited the aforementioned downregulation effect. In vivo, the introduction of miR-186-5p mimics enhanced angiogenesis in the CAM model. Conclusions: To summarize, our study reveals that MSC-EVs can restore the cellular function of DNR-damaged HCMEC and alleviate cellular senescence through the miR-185-5p-PARP9-STAT1/pSTAT1 pathway. This finding highlights the potential of MSC-EVs as a therapeutic strategy for mitigating the detrimental effects of anthracycline-induced endothelial damage