The specificities, influencing factors, and medical implications of bone circadian rhythms.

Physiological processes within the human body are regulated in approximately 24-h cycles known as circadian rhythms, serving to adapt to environmental changes. Bone rhythms play pivotal roles in bone development, metabolism, mineralization, and remodeling processes. Bone rhythms exhibit cell specificity, and different cells in bone display various expressions of clock genes. Multiple environmental factors, including light, feeding, exercise, and temperature, affect bone diurnal rhythms through the sympathetic nervous system and various hormones. Disruptions in bone diurnal rhythms contribute to the onset of skeletal disorders such as osteoporosis, osteoarthritis and skeletal hypoplasia. Conversely, these bone diseases can be effectively treated when aimed at the circadian clock in bone cells, including the rhythmic expressions of clock genes and drug targets. In this review, we describe the unique circadian rhythms in physiological activities of various bone cells. Then we summarize the factors synchronizing the diurnal rhythms of bone with the underlying mechanisms. Based on the review, we aim to build an overall understanding of the diurnal rhythms in bone and summarize the new preventive and therapeutic strategies for bone disorders.

A special role for anterior cingulate cortex, but not orbitofrontal cortex or basolateral amygdala, in choices involving information.

Subjects are often willing to pay a cost for information. In a procedure that promotes paradoxical choices, animals choose between a richer option followed by a cue that is rewarded 50% of the time (No Info) vs. a leaner option followed by one of two cues that signal certain outcomes: one always rewarded (100%) and the other never rewarded, 0% (Info). Since decisions involve comparing the subjective value of options after integrating all their features, preference for information may rely on cortico-amygdalar circuitry. To test this, male and female rats were prepared with bilateral inhibitory Designer Receptors Exclusively Activated by Designer Drugs (DREADDs) in the anterior cingulate cortex, orbitofrontal cortex, basolateral amygdala, or null virus (control). We inhibited these regions after stable preference was acquired. We found that inhibition of the anterior cingulate cortex destabilized choice preference in female rats without affecting latency to choose or response rate to cues. A logistic regression fit revealed that previous choice predicted current choice in all conditions, however previously rewarded Info trials strongly predicted preference in all conditions except in female rats following anterior cingulate cortex inhibition. The results reveal a causal, sex-dependent role for the anterior cingulate cortex in decisions involving information.

The Intermode Polariton Parametric Scattering Laser in a Strong Coupled Microcavity Via Two-Photon Absorption.

Exciton-polaritons, hybrid quasiparticles from the strong coupling of excitons and cavity photons in semiconductor microcavities, offer a platform for exploring quantum coherence and nonlinear optical properties. The unique polariton parametric scattering (PPS) laser is of interest for its potential in quantum technologies and nonlinear devices. However, direct resonant excitation of polaritons in strong-coupling microcavities is challenging. This study proposes an innovative two-photon absorption (TPA) pump mechanism to address this. We observe TPA-driven PPS lasing in a strongly coupled microcavity at room temperature. High K-value exciton injections promote coherent stimulated emission of polariton scattering through intermode channels. Angle-resolved spectra confirm a TPA process, showing evolution from pump-state to signal-state. Hanbury Brown-Twiss measurement of second-order correlation g2(τ) of signal state indicates a phase transition from a classical thermal state to a quantum coherent state. Theoretical modeling provides insights into the physical mechanisms of PPS. Our work advances nonlinear phenomena exploration in strongly coupled light-matter systems, contributing to quantum polaritonics and nonlinear optics.

Multi-omics analysis revealed that the protein kinase MoKin1 affected the cellular response to endoplasmic reticulum stress in the rice blast fungus, Magnaporthe oryzae.

BACKGROUND: Previous studies have shown that protein kinase MoKin1 played an important role in the growth, conidiation, germination and pathogenicity in rice blast fungus, Magnaporthe oryzae. ΔMokin1 mutant showed significant phenotypic defects and significantly reduced pathogenicity. However, the internal mechanism of how MoKin1 affected the development of physiology and biochemistry remained unclear in M. oryzae. RESULT: This study adopted a multi-omics approach to comprehensively analyze MoKin1 function, and the results showed that MoKin1 affected the cellular response to endoplasmic reticulum stress (ER stress). Proteomic analysis revealed that the downregulated proteins in ΔMokin1 mutant were enriched mainly in the response to ER stress triggered by the unfolded protein. Loss of MoKin1 prevented the ER stress signal from reaching the nucleus. Therefore, the phosphorylation of various proteins regulating the transcription of ER stress-related genes and mRNA translation was significantly downregulated. The insensitivity to ER stress led to metabolic disorders, resulting in a significant shortage of carbohydrates and a low energy supply, which also resulted in severe phenotypic defects in ΔMokin1 mutant. Analysis of MoKin1-interacting proteins indicated that MoKin1 really took participate in the response to ER stress. CONCLUSION: Our results showed the important role of protein kinase MoKin1 in regulating cellular response to ER stress, providing a new research direction to reveal the mechanism of MoKin1 affecting pathogenic formation, and to provide theoretical support for the new biological target sites searching and bio-pesticides developing.

Arterial pulsation dependence of perivascular cerebrospinal fluid flow measured by dynamic diffusion tensor imaging in the human brain.

Perivascular cerebrospinal fluid (pCSF) flow is a key component of the glymphatic system. Arterial pulsation has been proposed as the main driving force of pCSF influx along the superficial and penetrating arteries; however, evidence of this mechanism in humans is limited. We proposed an experimental framework of dynamic diffusion tensor imaging with low b-values and ultra-long echo time (dynDTIlow-b) to capture pCSF flow properties during the cardiac cycle in human brains. Healthy adult volunteers (aged 17-28 years; seven men, one woman) underwent dynDTIlow-b using a 3T scanner (MAGNETOM Prisma, Siemens Healthcare, Erlangen, Germany) with simultaneously recorded cardiac output. The results showed that diffusion tensors reconstructed from pCSF were mainly oriented in the direction of the neighboring arterial flow. When switching from vasoconstriction to vasodilation, the axial and radial diffusivities of the pCSF increased by 5.7 % and 4.94 %, respectively, suggesting that arterial pulsation alters the pCSF flow both parallel and perpendicular to the arterial wall. DynDTIlow-b signal intensity at b=0 s/mm2 (i.e., T2-weighted, [S(b=0 s/mm2)]) decreased in systole, but this change was ∼7.5 % of a cardiac cycle slower than the changes in apparent diffusivity, suggesting that changes in S(b=0 s/mm2) and apparent diffusivity arise from distinct physiological processes and potential biomarkers associated with perivascular space volume and pCSF flow, respectively. Additionally, the mean diffusivities of white matter showed cardiac-cycle dependencies similar to pCSF, although a delay relative to the peak time of apparent diffusivity in pCSF was present, suggesting that dynDTIlow-b could potentially reveal the dynamics of magnetic resonance imaging-invisible pCSF surrounding small arteries and arterioles in white matter; this delay may result from pulse wave propagation along penetrating arteries. In conclusion, the vasodilation-induced increases in axial and radial diffusivities of pCSF and mean diffusivities of white matter are consistent with the notion that arterial pulsation can accelerate pCSF flow in human brain. Furthermore, the proposed dynDTIlow-b technique can capture various pCSF dynamics in artery pulsation.

Functional Noncentrosymmetric Nanoparticle-Nanofiber Hybrids via Selective Fragmentation.

Noncentrosymmetric nanostructures are an attractive synthetic target as they can exhibit complex interparticle interactions useful for numerous applications. However, generating uniform, colloidally stable, noncentrosymmetric nanoparticles with low aspect ratios is a significant challenge using solution self-assembly approaches. Herein, we outline the synthesis of noncentrosymmetric multiblock co-nanofibers by subsequent living crystallization-driven self-assembly of block co-polymers, spatially confined attachment of nanoparticles, and localized nanofiber fragmentation. Using this strategy, we have fabricated uniform diblock and triblock noncentrosymmetric π-conjugated nanofiber-nanoparticle hybrid structures. Additionally, in contrast to Brownian motion typical of centrosymmetric nanoparticles, we demonstrated that these noncentrosymmetric nanofibers undergo ballistic motion in the presence of H2O2 and thus could be employed as nanomotors in various applications, including drug delivery and environmental remediation.

Accumulation of extracellular elastin-derived peptides disturbed neuronal morphology and neuron-microglia crosstalk in aged brain.

Extracellular elastin-derived peptides (EDPs) accumulate in the aging brain and have been associated with vascular dementia and Alzheimer's disease (AD). The activation of inflammatory processes in glial cells with EDP treatment has received attention, but not in neurons. To properly understand EDPs' pathogenic significance, the impact on neuronal function and neuron-microglia crosstalk was explored further. Among the EDP molecules, Val-Gly-Val-Ala-Pro-Gly (VGVAPG) is a typical repeating hexapeptide. Here, we observed that EDPs-VGVAPG influenced neuronal survival and morphology in a dose-dependent manner. High concentrations of VGVAPG induced synapse loss and microglia hyperactivation in vivo and in vitro. Following EDP incubation, galectin 3 (Gal-3) released by neurons served as a chemokine, attracting microglial engulfment. Blocking Gal-3 and EDP binding remedied synapse loss in neurons and phagocytosis in microglia. In response to the accumulation of EDPs, proteomics in matrix remodeling and cytoskeleton dynamics, such as a disintegrin and metalloproteinase (ADAM) family, were engaged. These findings in extracellular EDPs provided more evidence for the relationship between aging and neuron dysfunction, increasing the insight of neuroinflammatory responses and the development of new specialized extracellular matrix remolding-targeted therapy options for dementia or other neurodegenerative disease.

Apoptosis and pyroptosis in the nasal mucosa of Syrian hamster during SARS-CoV-2 infection and reinfection.

In SARS-CoV-2 infection, it has been observed that viral replication lasts longer in the nasal mucosa than in the lungs, despite the presence of a high viral load at both sites. In hamsters, we found that the nasal mucosa exhibited a mild inflammatory response and minimal pathological injuries, whereas the lungs displayed a significant inflammatory response and severe injuries. The underlying cellular events may be induced by viral infection in three types of cell death: apoptosis, pyroptosis, and necroptosis. Our findings indicate that apoptosis was consistently activated during infection in the nasal mucosa, and the levels of apoptosis were consistent with the viral load. On the other hand, pyroptosis and a few instances of necroptosis were observed only on 7 dpi in the nasal mucosa. In the lungs, however, both pyroptosis and apoptosis were prominently activated on 3 dpi, with lower levels of apoptosis compared to the nasal mucosa. Interestingly, in reinfection, obvious viral load and apoptosis in the nasal mucosa were detected on 3 dpi, while no other forms of cell death were detected. We noted that the inflammatory reactions and pathological injuries in the nasal mucosa were milder, indicating that apoptosis may play a role in promoting lower inflammatory reactions and milder pathological injuries and contribute to the generation of long-term viral replication in the nasal mucosa. Our study provides valuable insights into the differences in cellular mechanisms during SARS-CoV-2 infection and highlights the potential significance of apoptosis regulation in the respiratory mucosa for controlling viral replication.

IGFBP2 induces podocyte apoptosis promoted by mitochondrial damage via integrin α5/FAK in diabetic kidney disease.

Podocyte apoptosis or loss is the pivotal pathological characteristic of diabetic kidney disease (DKD). Insulin-like growth factor-binding protein 2 (IGFBP2) have a proinflammatory and proapoptotic effect on diseases. Previous studies have shown that serum IGFBP2 level significantly increased in DKD patients, but the precise mechanisms remain unclear. Here, we found that IGFBP2 levels obviously increased under a diabetic state and high glucose stimuli. Deficiency of IGFBP2 attenuated the urine protein, renal pathological injury and glomeruli hypertrophy of DKD mice induced by STZ, and knockdown or deletion of IGFBP2 alleviated podocytes apoptosis induced by high concentration of glucose or in DKD mouse. Furthermore, IGFBP2 facilitated apoptosis, which was characterized by increase in inflammation and oxidative stress, by binding with integrin α5 (ITGA5) of podocytes, and then activating the phosphorylation of focal adhesion kinase (FAK)-mediated mitochondrial injury, including membrane potential decreasing, ROS production increasing. Moreover, ITGA5 knockdown or FAK inhibition attenuated the podocyte apoptosis caused by high glucose or IGFBP2 overexpression. Taken together, these findings unveiled the insight mechanism that IGFBP2 increased podocyte apoptosis by mitochondrial injury via ITGA5/FAK phosphorylation pathway in DKD progression, and provided the potential therapeutic strategies for diabetic kidney disease.

Reversible Fusion-Fission MXene Fiber-Based Microelectrodes for Target-Specific Gram-Positive and Gram-Negative Bacterium Discrimination.

Inaccurate or cumbersome clinical pathogen diagnosis between Gram-positive bacteria (G+) and Gram-negative (G-) bacteria lead to delayed clinical therapeutic interventions. Microelectrode-based electrochemical sensors exhibit the significant advantages of rapid response and minimal sample consumption, but the loading capacity and discrimination precision are weak. Herein, we develop reversible fusion-fission MXene-based fiber microelectrodes for G+/G- bacteria analysis. During the fissuring process, the spatial utilization, loading capacity, sensitivity, and selectivity of microelectrodes were maximized, and polymyxin B and vancomycin were assembled for G+/G- identification. The surface-tension-driven reversible fusion facilitated its reusability. A deep learning model was further applied for the electrochemical impedance spectroscopy (EIS) identification in diverse ratio concentrations of G+ and G- of (1:100-100:1) with higher accuracy (>93%) and gave predictable detection results for unknown samples. Meanwhile, the as-proposed sensing platform reached higher sensitivity toward E. coli (24.3 CFU/mL) and S. aureus (37.2 CFU/mL) in 20 min. The as-proposed platform provides valuable insights for bacterium discrimination and quantification.

Exploration of the potential association between GLP-1 receptor agonists and suicidal or self-injurious behaviors: a pharmacovigilance study based on the FDA Adverse Event Reporting System database.

BACKGROUND: Establishing whether there is a potential relationship between glucagon-like peptide 1 receptor agonists (GLP-1RAs) and suicidal or self-injurious behaviors (SSIBs) is crucial for public safety. This study investigated the potential association between GLP-1RAs and SSIBs by exploring the FDA Adverse Event Reporting System (FAERS) database. METHODS: A disproportionality analysis was conducted using post-marketing data from the FAERS repository (2018 Q1 to 2022 Q4). SSIB cases associated with GLP-1RAs were identified and analyzed through disproportionality analysis using the information component. The parametric distribution with a goodness-of-fit test was employed to analyze the time-to-onset, and the Ω shrinkage was used to evaluate the potential effect of co-medication on the occurrence of SSIBs. RESULTS: In total, 204 cases of SSIBs associated with GLP-1RAs, including semaglutide, liraglutide, dulaglutide, exenatide, and albiglutide, were identified in the FAERS database. Time-of-onset analysis revealed no consistent mechanism for the latency of SSIBs in patients receiving GLP-1RAs. The disproportionality analysis did not indicate an association between GLP-1RAs and SSIBs. Co-medication analysis revealed 81 cases with antidepressants, antipsychotics, and benzodiazepines, which may be proxies of mental health comorbidities. CONCLUSIONS: We found no signal of disproportionate reporting of an association between GLP-1RA use and SSIBs. Clinicians need to maintain heightened vigilance on patients premedicated with neuropsychotropic drugs. This contributes to the greater acceptance of GLP-1RAs in patients with type 2 diabetes mellitus or obesity.

In Situ MOF-74-Pyrolysis-Generated Porous Carbon Supporting Spinel Cu0.15Co2.85O4/C Boosts Ammonium Perchlorate Accelerating Decomposition: Precise Cu Doping Modulating Oxygen Vacancy Concentration.

As one of the main components of solid propellant, ammonium perchlorate (AP) shows slow sluggish decomposition kinetics with unconcentrated heat release. To achieve efficient catalytical decomposition, it is a significant challenge to design reasonable catalyst structure and explore the interaction between catalyst and AP. Herein, a series of porous carbon supported spinel-typed homogeneous heterometallic composites CuxCo3-xO4/C via pyrolysis of MOF-74-Co doped Cu. On basis of precise electronic-structure-tuning through modulating Cu/Co ratio in MOF-74, Cu0.15Co2.85O4/C with 5% Cu-doping featuring oxygen vacancy concentration of 26.25% exhibits the decrease to 261.5 °C with heat release up to 1222.1 J g-1 (456.9 °C and 669.2 J g-1 for pure AP). The detail process of AP accelerated decomposition is approved by TG-DSC-FTIR-MS technique. Density functional theory calculation revealed that in the Cu0.15Co2.85O4/C, the distinctive ability for NH3 catalyzed oxidation assisted with absorption performance of active porous C boosts accelerating AP decomposition. The findings would provide an insight for perceiving and understanding AP catalytic decomposition.

Erythrocyte Membrane Camouflaged Nanotheranostics for Optical Molecular Imaging-Escorted Self-Oxygenation Photodynamic Therapy.

Hypoxic tumor microenvironment (TME) hampers the application of oxygen (O2)-dependent photodynamic therapy (PDT) in solid tumors. To address this problem, a biomimetic nanotheranostics (named MMCC@EM) is developed for optical molecular imaging-escorted self-oxygenation PDT. MMCC@EM is synthesized by encapsulating chlorin e6 (Ce6) and catalase (CAT) in metal-organic framework (MOF) nanoparticles with erythrocyte membrane (EM) camouflage. Based on the biomimetic properties of EM, MMCC@EM efficiently accumulates in tumor tissues. The enriched MMCC@EM achieves TME-activatable drug release, thereby releasing CAT and Ce6, and this process can be monitored through fluorescence (FL) imaging. In addition, endogenous hydrogen peroxide (H2O2) will be decomposed by CAT to produce O2, which can be reflected by the measurement of intratumoral oxygen concentration using photoacoustic (PA) imaging. Such self-oxygenation nanotheranostics effectively mitigate tumor hypoxia and improve the generation of singlet oxygen (1O2). The 1O2 disrupts mitochondrial function and triggers caspase-3-mediated cellular apoptosis. Furthermore, MMCC@EM triggers immunogenic cell death (ICD) effect, leading to an increased infiltration of cytotoxic T lymphocytes (CTLs) into tumor tissues. As a result, MMCC@EM exhibits good therapeutic effects in 4T1-tumor bearing mice under the navigation of FL/PA duplex imaging.

Deregulated mitochondrial quality control, the heel of Achilles in elucidating the role of autophagy in SARM1-mediated axon degeneration.

Autophagic dysfunction in neurodegenerative diseases is being extensively studied, yet the exact mechanism of macroautophagy/autophagy in axon degeneration is still elusive. A recent study by Kim et al. links autophagic stress to the sterile α and toll/interleukin 1 receptor motif containing protein 1 (SARM1)-dependent core axonal degeneration program, providing a new insight into the role of autophagy in axon degeneration. In the classical Wallerian axon degeneration model of axotomy, disruption of axonal transport destroys the coordinated activity of pro-survival and pro-degenerative factors in the axoplasm and activates the NADase activity of SARM1, thus triggering the axonal self-destruction program. However, the mechanism for SARM1 activation in the chronic neurodegenerative disorders is more complex. Mitochondrial defects and oxidative stress contribute to the activation of SARM1, while mitophagy can inhibit mitochondrial dysfunction and promote the clearance of SARM1 on mitochondria, thus protecting against neuronal degeneration. Therefore, in-depth elucidation of the underlying mechanisms of mitophagy during axonal degeneration can help develop promising strategies for the prevention and treatment of various neurodegenerative disorders.

Alternative splicing-related long noncoding RNA ANRIL facilitates hepatocellular carcinoma by targeting the miR-199a-5p/SRSF1 axis and impacting Anillin.

Hepatocellular carcinoma (HCC) is characterized by aberrant alternative splicing (AS), which plays an important part in the pathological process of this disease. However, available reports about genes and mechanisms involved in AS process are limited. Our previous research has identified ANRIL as a long noncoding RNA related to the AS process of HCC. Here, we investigated the exact effect and the mechanism of ANRIL on HCC progress. The ANRIL expression profile was validated using the real-time quantitative polymerase chain reaction assay. The western blot analysis and IHC assay were conducted on candidate targets, including SRSF1 and Anillin. The clinicopathological features of 97 patients were collected and analyzed. Loss-of and gain-of-function experiments were conducted. The dual-luciferase reporter assay was applied to verify the interaction between ANRIL, miR-199a-5p, and SRSF1. Anomalous upregulation of ANRIL in HCC was observed, correlating with worse clinicopathological features of HCC. HCC cell proliferation, mobility, tumorigenesis, and metastasis were impaired by depleting ANRIL. We found that ANRIL acts as a sponger of miRNA-199a-5p, resulting in an elevated level of its target protein SRSF1. The phenotypes induced by ANRIL/miR-199a-5p/SRSF1 alteration are associated with Anillin, a validated HCC promoter. ANRIL is an AS-related lncRNA promoting HCC progress by modulating the miR-199a-5p/SRSF1 axis. The downstream effector of this axis in the development of HCC is Anillin.

Identification and virus-induced gene silencing (VIGS) analysis of methyltransferase affecting tomato (Solanum lycopersicum) fruit ripening.

MAIN CONCLUSION: Six methyltransferase genes affecting tomato fruit ripening were identified through genome-wide screening, VIGS assay, and expression pattern analysis. The data provide the basis for understanding new mechanisms of methyltransferases. Fruit ripening is a critical stage for the formation of edible quality and seed maturation, which is finely modulated by kinds of factors, including genetic regulators, hormones, external signals, etc. Methyltransferases (MTases), important genetic regulators, play vital roles in plant development through epigenetic regulation, post-translational modification, or other mechanisms. However, the regulatory functions of numerous MTases except DNA methylation in fruit ripening remain limited so far. Here, six MTases, which act on different types of substrates, were identified to affect tomato fruit ripening. First, 35 MTase genes with relatively high expression at breaker (Br) stage of tomato fruit were screened from the tomato MTase gene database encompassing 421 genes totally. Thereafter, six MTase genes were identified as potential regulators of fruit ripening via virus-induced gene silencing (VIGS), including four genes with a positive regulatory role and two genes with a negative regulatory role, respectively. The expression of these six MTase genes exhibited diverse patterns during the fruit ripening process, and responded to various external ripening-related factors, including ethylene, 1-methylcyclopropene (1-MCP), temperature, and light exposure. These results help to further elaborate the biological mechanisms of MTase genes in tomato fruit ripening and enrich the understanding of the regulatory mechanisms of fruit ripening involving MTases, despite of DNA MTases.

Optimization of oral isavuconazole dose for population in special physiological or pathological state: a physiologically based pharmacokinetics model-informed precision dosing.

OBJECTIVE: To recommend precision dosing and improve therapeutic efficacy against invasive fungal disease, a physiologically based pharmacokinetic model (PBPK) of oral isavuconazole (ISA) was established and used to explore its disposition across populations in different physiological and pathological states. METHODS: Twenty-five pharmacokinetic (PK) studies of oral ISA were identified through a systematic search of PubMed. Concentration-time data were extracted using WebPlotDigitizer. Physiochemical parameters were obtained from published literature and DrugBank. Model development and simulation used the Simcyp population-based simulator, and visual predictive check and predictive error were used for the model evaluation. Probability of target attainment and the cumulative fraction of response analyses were performed for dose optimization. RESULTS: The developed PBPK model was successfully validated in different populations. Most predicted concentration-time points aligned with the observed data, with acceptable predictive errors for the critical parameters. We predicted the PK profiles and parameters of ISA in a population with severe hepatic impairment (HI), a population with obesity and paediatric patients aged 1 to less than 6 years old. The probability of target attainment and cumulative fraction of response analyses indicated that the population with severe HI should have half the maintenance dose. The population with obesity and population with severe HI should have a loading dose of 300 mg every 8 h for 2 days. For paediatric patients aged 1 to less than 6 years old, a weight-based dosing regimen (5.38 mg/kg) of ISA was suggested. CONCLUSION: The predicted value aligns with observations, suggesting ISA's potential predictability in PK profiles for other populations. The recommended dosing regimens increase our understanding of the use of ISA in special populations.

High-resolution and highly-multiplexed option for fiber-fed spectrograph of the wide field MUltiplexed Survey Telescope (MUST).

In recent decades, rapid advances in astronomical imaging campaigns have generated an urgent need for detailed spectroscopic surveys with increased speed and efficiency. The 6.5 m MUltiplexed Survey Telescope (MUST) aims to address these current demands. The performance of the multi-object fiber-fed spectrograph (MOFS) plays a critical role for spectroscopic survey telescopes, directly influencing the realization of scientific aims. In this paper, we demonstrate a high-resolution and highly-multiplexed option for MOFS of MUST. The system is believed to be first to apply a 92 mm × 92 mm large-size detector in a Schmidt-like camera and reduces the average central obscuration to 14%. Thanks to the F/1.25 camera design with excellent image quality, the spectrograph achieves up to 800 150µm-large-core optical fibers integration. It can obtain the broadband spectral information (395 nm-435 nm, 520 nm-570 nm, 610 nm-680 nm) of 800 objects with a high resolution of >16,000 within one exposure. The spectrograph theory, design method, and final system scheme of the MOFS can offer good reference and guidance for the spectrograph design in the spectroscopic survey.

Spatiotemporal variability in the diffuse attenuation coefficient of sea ice.

The diffuse attenuation coefficient (Kd) is known to be closely related to the light transmittance of sea ice, which plays a critical role in the energy balance and biological processes of the upper ocean. However, the commercial instruments cannot easily measure Kd in sea ice because sea ice is a solid. The authors of this study are developing an instrument with a high spectral solution to measure the irradiance profile of sea ice and the irradiance in the atmosphere. Three Kd experiments were carried out, including two in-situ experiments in the Liaodong Bay and one in the laboratory. The results showed that the Kd of the sea ice varied with depth, and the values in adjacent sea ice layers differed by up to 2 times. In addition, due to changes in the climate environment, the Kd of sea ice showed temporal variations. For example, there was a 1.38-fold difference in the Kd values of the surface layer of sea ice at different times in 2022. The values in different sea ice layers also showed different trends over time, and the coefficient of determination (R2) of Kd between adjacent layers over time was as low as 0.008. To explain the driving mechanism of spatio-temporal variability of Kd, an additional experiment focusing on the physical microstructure of sea ice was conducted in Liaodong Bay in 2022. The result shows that the change in air bubbles in the sea ice may be the main the reason for the change in Kd. For example, when the sea ice was exchanging brine and bubbles with the atmosphere above and the seawater below, the highly absorbent particles in it tend to remain in their original position. Considering that the total absorption coefficient changed slightly, the bubbles with the characteristic of intense scattering were found to be the main factor influencing the Kd changes. This conclusion is supported by the fact that the value of R2 between the bubbles and Kd was 0.52. If climatic changes have led to an increase in the volume of bubbles, the more bubbles will increase the scattering properties of sea ice and lead to an increase in Kd. Conversely, the reduced bubble volume would reduce the scattering properties of sea ice, which in turn would reduce Kd.

Data-based systematic error extraction and compensation methods based on wavelet transform in ultra-precision optical polishing.

Sub-aperture polishing is a key technique for fabricating ultra-precision optics. However, the existence of the polishing errors that are difficult to be compensated by physical modeling seriously affects the manufacturing accuracy and efficiency of optical components. To address this problem, a data-based systematic error extraction and compensation (DSEC) method was proposed to enhance the polishing accuracy on optics. To maximize the extraction quality in a small dataset condition, the wavelet transform is introduced into the extraction process, and the uncertainty of the piston term in the interferometer measurement is improved by L1-norm optimization. Furthermore, two typical error sources (loss of polishing fluid in the edge and the robot trajectory error) are used to verify the effectiveness of the proposed method; in experimental verification, the root mean square (RMS) of the surface figure of a ϕ85-mm mirror was decreased from 0.069λ to 0.017λ, and the RMS of the 610 × 440 mm mirrors was achieved at 0.019λ after the edge compensation, where the polishing accuracy can be improved by more than 4 times; additionally, the RMS of the surface figure with an effective aperture of 480 × 360 mm mirror was reached at 0.011λ after the trajectory error compensation, where the polishing accuracy can be improved by more than 2 times. The proposed DSEC model offers insights that will help achieve advancement in the sub-aperture polishing process.