基于密度泛函理论研究Ag-Co团簇的结构、电子和光学性能

基于密度泛函理论研究了7个原子Ag-Co团簇结构的稳定性、电子和光学性能.研究结果表明,7个原子Ag-Co团簇的最稳定结构都是十面体结构,Co原子数量较少时,Co原子主要占据十面体的轴向位,Ag原子主要占据赤道位,随着Co原子数的增加,Co原子逐渐替换了赤道位上的Ag原子.当Co原子数增加时,Ag-Co团簇的垂直电离势、垂直电子亲能和最高占据轨道与最低未占据轨道之间的能隙整体上都呈现出下降趋势,表明电子稳定性降低;Ag-Co团簇的吸收光谱整体出现了红移,吸收峰的强度逐渐减弱,吸收谱的宽度变窄.

Mouse Karyotype Obtained by Combining DAPI Staining with Image Analysis

In this study, mitotic metaphase chromosomes in mouse were identified by a new chromosome fluorescence banding technique combining DAPI staining with image analysis. Clear 4＇, 6-diamidino-2-phenylindole （DAPI） multiple bands like （J-hands could be produced in mouse. The Meta- Morph software was then used to generate linescans of pixel intensity for the banded chromosomes from short arm to long arm. These linescans were sufficient not only to identify each individual chromosome but also analyze the physical sites of bands in chromosome. Based on the results, the clear and accurate karyotype of mouse metaphase chromosomes was established. The technique is therefore considered to he a new method for cytological studies of mouse.

Rapid and Efficient Investigation of Ciliate Nuclear Development During Conjugation Through Optimizing Hoechst33342 Staining Workflow

Ciliates are eukaryotic unicellular organisms with complex morphology and developmental processes,including asexual and sexual processes.Conjugation is a form of sexual process that renews genetic materials.However,visualizing conjugation in ciliates is a challenge due to the complexity and dynamics of the process,while traditional staining methods are often insufficient for the research.This study introduces a new method for visualizing developmental progression in the nuclei during conjugation using Hoechst33342 staining.It describes how to proceed from cell culture,conjugation induction and synchronization,staining preparation,and observation to statistical analysis.The combination of fluorescent staining with the‘volume-fixing'technique eliminates the fixation and dehydration steps,thus reducing the overall operation time to just 20 minutes.This method offers several advantages over traditional staining techniques for studying the nuclei during conjugation.It improves image quality and workflow efficiency and enables real-time observation of live cell states.Potential solutions to challenges that may arise during experimental procedures are introduced and references and guidelines for cytological research are provided in this paper.

Application of Prussian blue staining in the diagnosis of ocular siderosis

AIM:To explore the value of Prussian blue staining in the diagnosis of ocular siderosis.METHODS:Between January 2012 and January 2013,the Prussian blue stain used in anterior lens capsule and vitreous liquid after centrifugation from patients with definitive diagnosis and suspicious diagnosed of ocular siderosis. At the same time, give a negative control.RESULTS:Anterior lens capsule membrane and liquid of vitreous cavity from patients with definitive diagnosis and suspicious diagnosed of ocular siderosis revealed ferric ions that stained positively with Prussian blue. In the control group, there is no positive reaction.CONCLUSION:Prussian blue staining in the diagnosis of ocular siderosis has a very significant worth,suspected cases can be definitive diagnosed.

Deep learning-based recognition of stained tongue coating images

Objective To build a dataset encompassing a large number of stained tongue coating images and process it using deep learning to automatically recognize stained tongue coating images.Methods A total of 1001 images of stained tongue coating from healthy students at Hunan University of Chinese Medicine and 1007 images of pathological(non-stained)tongue coat-ing from hospitalized patients at The First Hospital of Hunan University of Chinese Medicine withlungcancer;diabetes;andhypertensionwerecollected.Thetongueimageswererandomi-zed into the training;validation;and testing datasets in a 7:2:1 ratio.A deep learning model was constructed using the ResNet50 for recognizing stained tongue coating in the training and validation datasets.The training period was 90 epochs.The model’s performance was evaluated by its accuracy;loss curve;recall;F1 score;confusion matrix;receiver operating characteristic(ROC)curve;and precision-recall(PR)curve in the tasks of predicting stained tongue coating images in the testing dataset.The accuracy of the deep learning model was compared with that of attending physicians of traditional Chinese medicine(TCM).Results The training results showed that after 90 epochs;the model presented an excellent classification performance.The loss curve and accuracy were stable;showing no signs of overfitting.The model achieved an accuracy;recall;and F1 score of 92%;91%;and 92%;re-spectively.The confusion matrix revealed an accuracy of 92%for the model and 69%for TCM practitioners.The areas under the ROC and PR curves were 0.97 and 0.95;respectively.Conclusion The deep learning model constructed using ResNet50 can effectively recognize stained coating images with greater accuracy than visual inspection of TCM practitioners.This model has the potential to assist doctors in identifying false tongue coating and prevent-ing misdiagnosis.

TRANSMISSION ELECTRON MICROSCOPY OF SEGMENTED POLYURETHANES WITH RUTHENIUM TETROXIDE AS A STAINING AGENT

Microphase separation and lamellar structure of segmented polyether- and polyester-polyurethanes have been investigated by means of transmission electron microscopy with the ruthenium tetroxide staining technique. The results show that the RuO_4 staining technique is simpler and may give better image contrast than other staining methods for this polymer. Microphase separation and lamellar structure of segmented polyether-and polyester-polyurethanes were directly observed and discussed.

Dendritic spine degeneration:a primary mechanism in the aging process

Recent reports suggest that aging is not solely a physiological process in living beings;instead, it should be considered a pathological process or disease(Amorim et al., 2022). Consequently, this process involves a wide range of factors, spanning from genetic to environmental factors, and even includes the gut microbiome(GM)(Mayer et al., 2022). All these processes coincide at some point in the inflammatory process, oxidative stress, and apoptosis, at different degrees in various organs and systems that constitute a living organism(Mayer et al., 2022;AguilarHernández et al., 2023).

Regeneration mechanisms and therapeutic strategies for neuromuscular junctions in aging and diseases

The neuromuscular junction(NMJ)is an essential synaptic structure composed of motor neurons,skeletal muscles,and glial cells that orchestrate the critical process of muscle contraction(Li et al.,2018).The typical NMJ structure is classically described as having a“pretzel-like”shape in mice(Figure 1),whereas human NMJs have a smaller,fragmented structure throughout adulthood.Degenerated NMJs exhibit smaller or fragmented endplates,partial denervation,reduced numbers of synaptic vesicles,abnormal presynaptic mitochondria,and dysfunctional perisynaptic Schwann cells(Alhindi et al.,2022).

Decline and fall of aging astrocytes:the human perspective

“Last scene of all that ends this strange,eventful history,is second childishness and mere oblivion.I am sans teeth,sans eyes,sans taste,sans everything.”William Shakespeare‘As You Like It'Act 2,Sc.7,l.139Aging of the human brain is characterized by a progressive decline of its functional capacity;this decline however varies widely,and cognitive longevity differs substantially between individuals.

A RAPID STAINING METHOD SHOWING AgNOR AND DNA IN PATHOLOGICAL DIAGNOSIS

In order to satisfy the need of rapid clinical diagnosis, a series of experimental studies for AgNOR (Argyrophilic NORassociated proteins) and DNA (Dereyribonucleic acid) staining was compared, from which a stable staining solution was selected to show mucin residence. Using the referred tables, with reference to the corresponding relation of the staining solution with temperature and time, reliable staining results for AgNOR and DNA could be obtained.These two modified staining methods are simple, reliable and easy to operate, able to provide good contrast for pathological diagnosis.

Comparative Investigation of Alternative Negative Staining Reagents in Bacterial Morphological Study

Negative staining is an effective method that can be used for electron microscopic study to observe fine structural morphology without destruction of bacterial structure. Although uranium acetate is used worldwide as a general dyeing solution, it is extremely difficult to use it by a new purchase at a research institution because it falls under the nuclear regulation substance in Japan. Therefore, we examined alternative reagents for negative staining that could replace uranium acetate through bacterial observation with an electron microscope. Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Streptococcus pyogenes were examined by four stain reagents (phosphotungstic acid (PTA), EMstainer, TI blue, and uranium acetate). Pre cultured bacteria were stained with each stain reagents on a copper grid, washed with PBS, and observed with a transmission electron microscope. In the comparison between bacterial structures, the cell wall structure and bacterial flagella could be observed well in the order of PTA, EMstainer, and uranium acetate. With TI blue staining, flagella could be observed very poorly. In comparison between bacteria, gram negative bacteria such as Escherichia coli and Pseudomonas aeruginosa, could be observed well as compared with gram positive cocci such as Staphylococcus aureus and Streptococcus pyogenes. The uranium acetate looked very coarse in background particles. Since crystals tend to precipitate, TI blue also required filtering, and electron beams were absorbed by the agglomerated crystals, and the frequency of electronic burning occurred high frequency. In this study, there was clear difference in the observation conditions depending on the type of bacteria and the kind of the staining reagents. Especially, it was confirmed that good negative staining features of Pseudomonas aeruginosa by electron microscope were obtained by PTA and EMstainer staining. These alternative reagents are considered to be a candidate for a negative staining.

Comparative Study of Z N Staining vs. Flurochrome Staining and Impact of Sample Processing on Diagnosis of Tuberculosis from Various Clinical Samples

Background: Tuberculosis is a highly infectious disease and India has the highest burden with it. Diagnosis of tuberculosis in many countries is still dependent on microscopy. Although its sensitivity is low in comparison to culture and molecular methods, its sensitivity can still be improved by using fluorescence staining method and processing of samples by homogenization and concentration method. Material and methods: Samples were collected from all newly registered suspected cases of tuberculosis in tertiary care hospital from outward and indoor department during a period of one year. Smears were prepared for Ziehl Neelsen stain and fluorescence stain both before and after homogenization and concentration procedure by 4% NAOH-2.9% sodium citrate method and results of them were interpreted according to RNTCP criteria for grading of sputum samples. All the samples were cultured in liquid culture MGIT system (Mycobacterial Growth Indicator Tube) and results of microscopy were compared with liquid culture taken as gold standard. Data were analyzed by using SPSS software version 16. Result: 350 samples were collected during study period. Out of 350 samples, 48 samples were positive for M. tuberculosis by MGIT system. In comparison with MGIT system, sensitivity of Z N stain for detection of acid fast bacilli was 77% before decontamination procedure, which was increased up to 85.42% after decontamination and concentration process. Sensitivity of fluroscence stain was 85.42% before processing, which was increased up to 91.67% after processing of samples. Conclusion: Sensitivity of smear microscopy can be enhanced by use of fluroscence microscopy and concentration method.

Neuronal regulated cell death in aging-related neurodegenerative diseases:key pathways and therapeutic potentials

Regulated cell death(such as apoptosis,necroptosis,pyroptosis,autophagy,cuproptosis,ferroptosis,disulfidptosis)involves complex signaling pathways and molecular effectors,and has been proven to be an important regulatory mechanism for regulating neuronal aging and death.However,excessive activation of regulated cell death may lead to the progression of aging-related diseases.This review summarizes recent advances in the understanding of seven forms of regulated cell death in age-related diseases.Notably,the newly identified ferroptosis and cuproptosis have been implicated in the risk of cognitive impairment and neurodegenerative diseases.These forms of cell death exacerbate disease progression by promoting inflammation,oxidative stress,and pathological protein aggregation.The review also provides an overview of key signaling pathways and crosstalk mechanisms among these regulated cell death forms,with a focus on ferroptosis,cuproptosis,and disulfidptosis.For instance,FDX1 directly induces cuproptosis by regulating copper ion valency and dihydrolipoamide S-acetyltransferase aggregation,while copper mediates glutathione peroxidase 4 degradation,enhancing ferroptosis sensitivity.Additionally,inhibiting the Xc-transport system to prevent ferroptosis can increase disulfide formation and shift the NADP^(+)/NADPH ratio,transitioning ferroptosis to disulfidptosis.These insights help to uncover the potential connections among these novel regulated cell death forms and differentiate them from traditional regulated cell death mechanisms.In conclusion,identifying key targets and their crosstalk points among various regulated cell death pathways may aid in developing specific biomarkers to reverse the aging clock and treat age-related neurodegenerative conditions.

A revisit to staining reagents for neuronal tissues

In the early days of deciphering the injured neuronal tissues led to the realization that contrast is necessary to discern the parts of the recovering tissues from the damaged ones.Early attempts relied on available(and often naturally occurring)staining substances.Incidentally,the active ingredients of most of them were small molecules.With the advent of time,the knowledge of chemistry helped identify compounds and conditions for staining.The staining reagents were even found to enhance the visibility of the organelles.Silver impregnation identification of Golgi bodies was discovered in owl optic nerve.Staining reagents since the late 1800s were widely used across all disciplines and for nerve tissue and became a key contributor to advancement in nerve-related research.The use of these reagents provided insight into the organization of the neuronal tissues and helped distinguish nerve degeneration from regeneration.The neuronal staining reagents have played a fundamental role in the clinical research facilitating the identification of biological mechanisms underlying eye and neuropsychiatric diseases.We found a lack of systematic description of all staining reagents,whether they had been used historically or currently used.There is a lack of readily available information for optimal staining of different neuronal tissues for a given purpose.We present here a grouping of the reagents based on their target location:(I)the central nervous system(CNS),(II)the peripheral nervous system(PNS),or(III)both.The biochemical reactions of most of the staining reagents is based on acidic or basic pH and specific reaction partners such as organelle or biomolecules that exists within the given tissue type.We present here a summary of the chemical composition,optimal staining condition,use for given neuronal tissue and,where possible,historic usage.Several biomolecules such as lipids and metabolites lack specific antibodies.Despite being non-specific the reagents enhance contrast and provide corroboration about the microenvironment.In future,these reagents in combination with emerging techniques such as imaging mass spectrometry and kinetic histochemistry will validate or expand our understanding of localization of molecules within tissues or cells that are important for ophthalmology and vision science.

Decoding molecular mechanisms:brain aging and Alzheimer's disease

The complex morphological,anatomical,physiological,and chemical mechanisms within the aging brain have been the hot topic of research for centuries.The aging process alters the brain structure that affects functions and cognitions,but the worsening of such processes contributes to the pathogenesis of neurodegenerative disorders,such as Alzheimer's disease.Beyond these observable,mild morphological shifts,significant functional modifications in neurotransmission and neuronal activity critically influence the aging brain.Understanding these changes is important for maintaining cognitive health,especially given the increasing prevalence of age-related conditions that affect cognition.This review aims to explore the age-induced changes in brain plasticity and molecular processes,differentiating normal aging from the pathogenesis of Alzheimer's disease,thereby providing insights into predicting the risk of dementia,particularly Alzheimer's disease.

Unraveling brain aging through the lens of oral microbiota

The oral cavity is a complex physiological community encompassing a wide range of microorganisms.Dysbiosis of oral microbiota can lead to various oral infectious diseases,such as periodontitis and tooth decay,and even affect systemic health,including brain aging and neurodegenerative diseases.Recent studies have highlighted how oral microbes might be involved in brain aging and neurodegeneration,indicating potential avenues for intervention strategies.In this review,we summarize clinical evidence demonstrating a link between oral microbes/oral infectious diseases and brain aging/neurodegenerative diseases,and dissect potential mechanisms by which oral microbes contribute to brain aging and neurodegeneration.We also highlight advances in therapeutic development grounded in the realm of oral microbes,with the goal of advancing brain health and promoting healthy aging.

Gut microbiota-astrocyte axis: new insights into age-related cognitive decline

With the rapidly aging human population,age-related cognitive decline and dementia are becoming increasingly prevalent worldwide.Aging is considered the main risk factor for cognitive decline and acts through alterations in the composition of the gut microbiota,microbial metabolites,and the functions of astrocytes.The microbiota–gut–brain axis has been the focus of multiple studies and is closely associated with cognitive function.This article provides a comprehensive review of the specific changes that occur in the composition of the gut microbiota and microbial metabolites in older individuals and discusses how the aging of astrocytes and reactive astrocytosis are closely related to age-related cognitive decline and neurodegenerative diseases.This article also summarizes the gut microbiota components that affect astrocyte function,mainly through the vagus nerve,immune responses,circadian rhythms,and microbial metabolites.Finally,this article summarizes the mechanism by which the gut microbiota–astrocyte axis plays a role in Alzheimer’s and Parkinson’s diseases.Our findings have revealed the critical role of the microbiota–astrocyte axis in age-related cognitive decline,aiding in a deeper understanding of potential gut microbiome-based adjuvant therapy strategies for this condition.

Age-related driving mechanisms of retinal diseases and neuroprotection by transcription factor EB-targeted therapy

Retinal aging has been recognized as a significant risk factor for various retinal disorders,including diabetic retinopathy,age-related macular degeneration,and glaucoma,following a growing understanding of the molecular underpinnings of their development.This comprehensive review explores the mechanisms of retinal aging and investigates potential neuroprotective approaches,focusing on the activation of transcription factor EB.Recent meta-analyses have demonstrated promising outcomes of transcription factor EB-targeted strategies,such as exercise,calorie restriction,rapamycin,and metformin,in patients and animal models of these common retinal diseases.The review critically assesses the role of transcription factor EB in retinal biology during aging,its neuroprotective effects,and its therapeutic potential for retinal disorders.The impact of transcription factor EB on retinal aging is cell-specific,influencing metabolic reprogramming and energy homeostasis in retinal neurons through the regulation of mitochondrial quality control and nutrient-sensing pathways.In vascular endothelial cells,transcription factor EB controls important processes,including endothelial cell proliferation,endothelial tube formation,and nitric oxide levels,thereby influencing the inner blood-retinal barrier,angiogenesis,and retinal microvasculature.Additionally,transcription factor EB affects vascular smooth muscle cells,inhibiting vascular calcification and atherogenesis.In retinal pigment epithelial cells,transcription factor EB modulates functions such as autophagy,lysosomal dynamics,and clearance of the aging pigment lipofuscin,thereby promoting photoreceptor survival and regulating vascular endothelial growth factor A expression involved in neovascularization.These cell-specific functions of transcription factor EB significantly impact retinal aging mechanisms encompassing proteostasis,neuronal synapse plasticity,energy metabolism,microvasculature,and inflammation,ultimately offering protection against retinal aging and diseases.The review emphasizes transcription factor EB as a potential therapeutic target for retinal diseases.Therefore,it is imperative to obtain well-controlled direct experimental evidence to confirm the efficacy of transcription factor EB modulation in retinal diseases while minimizing its risk of adverse effects.

The effect of different staining agents on the staining intensity of esterase isozyme zymogram of rice

Almost all previous reports on plant esterase(EST)isoenzyme analysis appeared to have ac-cepted that the relative staining strength(RSS)ofelectrophoretical bands represented the relative ac-tivities and contents of the correspondingisoenzymes.Nevertheless,we found in studyingthat the RSS changed with different staining

Ni-Ag双原子团簇催化甲烷干法重整反应的理论研究

甲烷干重整制合成气是将温室气体转换为合成气的有效途径,兼具环境效益和经济效益.本文采用密度泛函理论方法对Ni-Ag双原子团簇催化甲烷干重整反应的体系进行理论研究,对势能面上各驻点进行了全几何参数优化,通过频率分析确认了过渡态,并通过内禀反应坐标方法进行了验证,得出各基元反应的能量最低路径.研究结果对于理解在Ni上引入第二种金属Ag形成双原子团簇催化甲烷干法重整的理论研究有一定的意义,并为下一步实验研究提供理论基础.