Dynamic Changes In Distribution Research Articles

Enhancing time series data classification for structural damage detection through out-of-distribution representation learning

The analysis and classification of time series data, notably within Structural Health Monitoring (SHM) systems, face profound challenges due to the nonstationary nature of the data and changes in distribution over time. Additionally, the complexity of the SHM systems' time series datasets also relates to the presence of elusive latent distributions, making it challenging to pinpoint the dynamics of data distribution shifts. Therefore, this paper uses a Deep Learning (DL) model to address dynamic distribution changes and target elusive latent distributions in the data of SHM systems by adopting an out-of-distribution (OOD) representation learning method. The core idea is that by using adversarial training and domain-invariant feature learning, the used model enhances the analysis of time series data by dividing the data into distinct latent sub-domains, aiming to maximize the variance in distribution between each segment, facilitating a more unified analysis across different data segments. The effectiveness is demonstrated through testing on extensive datasets, including both real-world bridge data and laboratory data, showing a significant improvement over traditional DL models, especially in its ability to generalize to new, unseen distributions.

A space-time flow LISA approach for panel flow data

Spatial flow data represent meaningful spatial interaction (SI) phenomena between geographic regions that are often highly dynamic. However, most existing flow analytical methods are cross-sectional, and there is a lack of methods to measure spatiotemporal autocorrelation of flow data. To fill this gap, we proposed a new localized spatial statistical method called Space-Time Flow LISA. The method design is a combination of two existing method families, namely space-time LISA and Spatial Flow LISA. A critical component of the method is the space-time weight matrix of flow data that blends pairwise spatial and temporal connectivities. We design three versions of the matrix, namely contemporaneous, lagged, and hybrid. We evaluate the method using both synthetic data and a case study of U.S. interstate migration from 2005 to 2017. The method is found to have high efficacy in finding spatiotemporal local autocorrelation patterns. Unlike the Spatial Flow LISA that tends to detect short-distance migration corridor havens (‘HH’ flows) and long-distance migration corridor deserts (‘LL’ flows), the Space-Time Flow LISA is less impeded by the distance between flow origin and destination, as they can pick up local patterns that are less spatially explicit but temporally dependent. In addition, the new method is able to detect time-sensitive patterns such as the outmigration from Louisiana forced by Hurricane Katrina in 2005. By integrating spatial, temporal, and attributive associations into a one-step analysis, the proposed Space-Time Flow LISA can illustrate the spatiotemporal structure of flow phenomena well, and reveal dynamic distribution changes over time.

Distribution areas and monthly dynamic distribution changes of three Aedes species in China: Aedes aegypti, Aedes albopictus and Aedes vexans.

Mosquitoes play an absolute role in the spread of epidemic arbovirus diseases. Worldwide, Aedes aegypti and Aedes albopictus are the main vectors responsible for the spread of these mosquito-borne diseases. Aedes vexans, a mosquito species native to China, also carries mosquito-borne viruses, such as dengue fever virus and Japanese encephalitis virus, but research on this mosquito has been inadequate. Mapping the potential distribution range of and monthly change in the distribution of these three Aedes species is of particular importance for mosquito surveillance, eradication and disease control. Monitoring data were collected for the three Aedes species in China. Long-term temperature and precipitation data (2001-2021) and land cover data were used to represent various climate and environmental conditions. An ecological niche model was developed using a maximum entropy modeling method to predict the current optimum habitat areas for the three Aedes species and to obtain important variables influencing their monthly distribution. The distribution model for the three Aedes species performed well, with an area under the receiver operating characteristic curve value of 0.991 for Ae. aegypti, 0.928 for Ae. albopictus and 0.940 for Ae. vexans. Analysis of the distribution change and mapping of the optimum habitat range for each Aedes species for each month demonstrated that temperature, precipitation and construction land were important factors influencing the distribution of these three Aedes species. In China, Aedes aegypti is mainly concentrated in a few tropical regions and along the Yunnan border; Aedes albopictus is widely distributed throughout most of the country, except for the arid and semi-arid regions of northwest China; and Aedes vexans is mainly found in the northern regions. Our results provide a basis for the timing and location of surveillance efforts for high-priority mosquitoes.

A federated learning and blockchain framework for physiological signal classification based on continual learning

A key challenge of physiological signal processing in the Internet of Medical Things is that physiological signals usually have dynamic distribution changes. Another challenge is that patients' data is vulnerable to disclosures. To address these problems, we propose a meta continual learning method, called MetaCL. MetaCL consists of a shared feature extractor, a knowledge base, a micro classifier module and a blockchain module. The shared feature extractor adopts a horizontal federated learning mechanism to prevent data leakage. The knowledge base is built and updated based on a Splite-based method to overcome catastrophic forgetting. The micro classifier module uses a mean-based model transfer method to adapt to the emergence of new classes. It integrates a Kullback-Leibler divergence regularization to the loss function to deal with fuzzy boundaries of classes. The blockchain module is designed based on the Alliance chain to protect the privacy of the classification results. Experiment results show that refinement classification performance of MetaCL is 98.35%, which outperforms the compared state-of-the-art works. The backward transfer under four increment scenarios is all within -2.6%. At last, a blockchain-based engineering application is presented to show that MetaCL can prevent privacy protection in the Internet of Medical Things (IoMT).

Cell-permeable fluorescent chemical sensors for imaging phosphoinositides

Phosphoinositides are anionic phospholipids that mediate key cellular processes like membrane trafficking and signal transduction. Dynamic changes in distribution and levels of phosphoinositides act as initiating flags for cell-signaling events. Hence, the ability to track phosphoinositide dynamics in living cells can provide mechanistic insights into fundamental cellular processes and help guide therapeutic interventions for diseases linked to impaired phosphoinositide metabolism. In this context, optical imaging can afford the requisite spatiotemporal resolution for tracking phosphoinositides.

Early Development of Resident Macrophages in the Mouse Cochlea Depends on Yolk Sac Hematopoiesis.

Resident macrophages reside in all tissues throughout the body and play a central role in both tissue homeostasis and inflammation. Although the inner ear was once believed to be “immune-privileged,” recent studies have shown that macrophages are distributed in the cochlea and may play important roles in the immune system thereof. Resident macrophages have heterogeneous origins among tissues and throughout developmental stages. However, the origins of embryonic cochlear macrophages remain unknown. Here, we show that the early development of resident macrophages in the mouse cochlea depends on yolk sac hematopoiesis. Accordingly, our results found that macrophages emerging around the developing otocyst at E10.5 exhibited dynamic changes in distribution and in situ proliferative capacity during embryonic and neonatal stages. Cochlear examination in Csf1r-null mice revealed a substantial decrease in the number of Iba1-positive macrophages in the spiral ganglion and spiral ligament, whereas they were still observed in the cochlear mesenchyme or on the intraluminal surface of the perilymphatic space. Our results demonstrated that two subtypes of resident macrophages are present in the embryonic cochlea, one being Csf1r-dependent macrophages that originate from the yolk sac and the other being Csf1r-independent macrophages that appear to be derived from the fetal liver via systemic circulation. We consider the present study to be a starting point for elucidating the roles of embryonic cochlear resident macrophages. Furthermore, resident macrophages in the embryonic cochlea could be a novel target for the treatment of various inner ear disorders.

Dynamic changes in the distribution of facial and abdominal adipose tissue correlated with surgical treatment in acromegaly.

Acromegaly is a systemic metabolic disease. Growth hormone (GH) have a significant impact on adipose tissue (AT). A huge reduction of serum GH after surgical treatment may cause substantial AT redistribution. The objective of this study was to illustrate the dynamic changes in distribution of facial and abdominal AT correlated with surgical treatment in patients with acromegaly. Abdominal AT in 17 acromegaly patients (group 1) was studied longitudinally preoperatively and 1 month to 1 year postoperatively. The facial and abdominal subcutaneous AT (fSAT and aSAT) of another 17 acromegaly patients (group 2) were compared with 7 nonfunctional pituitary adenoma (NFPA) controls. The areas of fSAT, aSAT, and visceral adipose tissue (VAT) were obtained by MRI and quantified by image analysis software, and intrahepatic lipid (IHL) was assessed by 1H magnetic resonance spectroscopy (MRS). Abdominal adipose tissue (aSAT, VAT, and IHL) increased overall after surgical treatment. However, IHL first decreased and then continuously increased during the follow-up. Compared with the increased amount of aSAT, the fSAT amount decreased after surgical treatment. The inconsistency of this phenomenon did not appear in the NFPA control subjects. The perioperative dynamic distribution of the facial and abdominal fat in acromegaly revealed regional differences in the intricate effect of GH on adipose tissue. Reduction of serum GH after surgical treatment of acromegaly was associated with dynamic increases of IHL, abdominal visceral, and subcutaneous fat, but a reduction of facial subcutaneous fat.

The effect of ionic liquids pretreatment on the distribution and structure of alkali-soluble hemicelluloses from Eucalyptus

Abstract In this study, Eucalyptus was treated by an integrated process based on ionic liquids ([Bmim]Cl and [Bmim]OAc) combined with successive alkali solutions (0.5, 2.0, and 4.0% NaOH). The dynamic distribution changes of hemicelluloses on the morphologically distinct regions in the treated Eucalyptus cell walls revealed that the dissolution of hemicelluloses mainly occurred in the secondary layers during this process. In addition, the structural features of alkali-soluble hemicelluloses dissolved from ionic liquids pretreated Eucalyptus were thoroughly investigated. The [Bmim]OAc pretreatment promoted the separation of hemicelluloses with relatively high molecular weights in the following alkali extractions, accompanying with slightly structural changes. The alkali-soluble hemicelluloses obtained from Eucalyptus are characterized to be a linear backbone of (1 → 4)-linked-β-D-xylopyranosyl residues decorated with branch at O-2 of 4-O-methyl-α-glucuronic acid unit. Additionally, the thermal stability of hemicelluloses was also increased by the ionic liquids pretreatment.

Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A) Protein Is Involved in Centrosome Separation through the Regulation of NIMA (Never In Mitosis Gene A)-related Kinase 2 (NEK2) Protein Activity

Cancerous inhibitor of protein phosphatase 2A (CIP2A) is overexpressed in most human cancers and has been described as being involved in the progression of several human malignancies via the inhibition of protein phosphatase 2A (PP2A) activity toward c-Myc. However, with the exception of this role, the cellular function of CIP2A remains poorly understood. On the basis of yeast two-hybrid and coimmunoprecipitation assays, we demonstrate here that NIMA (never in mitosis gene A)-related kinase 2 (NEK2) is a binding partner for CIP2A. CIP2A exhibited dynamic changes in distribution, including the cytoplasm and centrosome, depending on the cell cycle stage. When CIP2A was depleted, centrosome separation and the mitotic spindle dynamics were impaired, resulting in the activation of spindle assembly checkpoint signaling and, ultimately, extension of the cell division time. Our data imply that CIP2A strongly interacts with NEK2 during G2/M phase, thereby enhancing NEK2 kinase activity to facilitate centrosome separation in a PP1- and PP2A-independent manner. In conclusion, CIP2A is involved in cell cycle progression through centrosome separation and mitotic spindle dynamics.

Supercontinuum Dynamically Visualizes a Dividing Single Cell

During cell division, various organelles behave dynamically. Visualization of these dynamic behaviors of organelles is a promising one step forward for understanding life at the molecular level. One- or two-photon excited fluorescence microscopy has so far been used for visualizing these cell dynamics. The fluorescent probe introduced into a living cell can visualize the spatial distribution of a target molecule in real time, enabling the tracing of cell dynamics at the molecular level. Introducing a fluorescent probe into a cell, however, may alter the physical and chemical conditions of the cell. Here we show a new method for direct (no need for staining cells) visualization of living cell processes with coherent anti-Stokes Raman scattering (CARS) spectroscopy. A new light source, supercontinuum generated from a photonic crystal fiber, has facilitated ultrabroadband (>3500 cm(-1)) multiplex CARS spectroscopy and imaging with high molecular specificity. Using this multiplex CARS technique, we have been successful in tracing the whole cell division process, the splitting of a mother cell into two daughter cells, appearance and disappearance of septum, and dynamic distribution changes of organelles consisting of lipid membrane. The supercontinuum has also facilitated simultaneous measurement of the CARS and two-photon excited fluorescence (TPEF) spectra, enabling what we call multiple nonlinear spectral imaging. Three-dimensional image reconstruction of a living cell with high speed is now possible to elucidate more detailed molecular-level dynamics inside a dividing living cell.

Visualization and Characterization of High‐Order Chromatin Fibers under Light Microscope during Interphase and Mitotic Stages in Plants

Abstract Using genomic in situ hybridization with genomic DNA, high‐order chromatin fibers were successfully exhibited under a light microscope through the cell cycle in barley, rice, maize and field bean. From the interphase to prophase and metaphase of mitosis, the fibers were basically similar. Each was estimated to be around 200 nm in diameter, but the strength of signals was not the same along the fiber length. Through the cell cycle a series of dynamic distribution changes occurred in the fibers. In the interphase, they were unraveled. At the early prophase they were arranged with parallel and mirror symmetry. During late‐prophase and metaphase, the fibers were bundled and became different visible chromosomes. The parallel coiling and mirror symmetry structures were visible clearly until the metaphase. In anaphase they disappeared. During telophase, in peripheral regions of congregated chromosome group, borderlines of the chromosomes disappeared and the fibers were unraveled. This demonstrated that mitotic chromosomes are assembled and organized by parallel and adjacent coiling of the fibers and the fibers should be the highest order structure for DNA coiling.

Epidemiological study on pathogens of deep fungal infection

目的 了解广东地区医院近年深部真菌感染的动态变化,为临床经验性治疗提供依据.方法 回顾分析了1998-2004年我科真菌室接受的疑诊为深部真菌感染的标本9574份,分离出阳性标本3122份(阳性率32.6%),共13个菌种.药敏试验采用浓度梯度法.结果真菌学变化:白念珠菌近3年所占构成比:白念珠菌在2002-2004年组所占构成比与1998-2001年组相比显著下降(76.3%、66.8%比较,χ=34.33,P＜0.05);光滑念珠菌、近平滑念珠菌构成比显著增加(4.2%、11.1%比较,χ2=51.30,P＜0.05,2.2%、4.0%比较,χ2=8.82,P＜0.05);马内菲青霉菌近年呈现增多趋势.药敏试验:2000-2004年703株真菌菌株药敏试验结果显示,对伊曲康唑、氟康唑、酮康唑、两性霉素的耐药株均无增加趋势,伊曲康唑敏感株显著减少(71.0%、58.2%比较χ2=16.50,P＜0.05),中介株显著增多(7.8%、24.8%比较,χ2=24.8,P＜0.05),其中以白念珠菌、热带念珠菌对伊曲康唑敏感株减少为主.结论 白念珠菌近年所占构成比显著下降;光滑念珠菌、近平滑念珠菌构成比显著增加;出现了新的感染菌株马内菲青霉菌.白念珠菌、热带念珠菌对伊曲康唑敏感株显著减少.此种真菌菌学变迁及药敏试验的变化应引起临床医师重视。

Localization and Function of SolubleN-Ethylmaleimide-sensitive Factor Attachment Protein-25 and Vesicle-associated Membrane Protein-2 in Functioning Gastric Parietal Cells

The soluble N-ethylmaleimide-sensitive factor attachment protein of 25 kDa (SNAP-25) plays an important role in vesicle trafficking. Together with vesicle-associated membrane protein-2 (VAMP-2) and syntaxin, SNAP-25 forms a ternary complex implicated in docking and fusion of secretory vesicles with the plasma membrane during exocytosis. These so-called SNARE proteins are believed to regulate tubulovesicle trafficking and fusion during the secretory cycle of the gastric parietal cell. Here we examined the cellular localization and functional importance of SNAP-25 in parietal cell cultures. Adenoviral constructs were used to express SNAP-25 tagged with cyan fluorescent protein, VAMP-2 tagged with yellow fluorescent protein, and SNAP-25 in which the C-terminal 25 amino acids were deleted (SNAP-25 Delta181-206). Membrane fractionation experiments and fluorescent imaging showed that SNAP-25 is localized to the apical plasma membrane. The expression of the mutant SNAP-25 Delta181-226 inhibited the acid secretory response of parietal cells. Also, SNAP Delta181-226 bound poorly in vitro with recombinant syntaxin-1 compared with wild type SNAP-25, indicating that pairing between syntaxin-1 and SNAP-25 is required for parietal cell activation. Dual expression of SNAP-25 tagged with cyan fluorescent protein and VAMP-2 tagged with yellow fluorescent protein revealed a dynamic change in distribution associated with acid secretion. In resting cells, SNAP-25 is at the apical plasma membrane and VAMP-2 is associated with cytoplasmic H,K-ATPase-rich tubulovesicles. After stimulation, the two proteins co-localize on the apical plasma membrane. These data demonstrate the functional significance of SNAP-25 as a SNARE protein in the parietal cell and show the dynamic stimulation-associated redistribution of VAMP-2 from H,K-ATPase-rich tubulovesicles to co-localize with SNAP-25 on the apical plasma membrane.

Nek2 Localizes to Multiple Sites in Mitotic Cells, Suggesting Its Involvement in Multiple Cellular Functions during the Cell Cycle

Nek2 is a mammalian protein kinase that is structurally homologous to NIMA, a mitotic regulator in Aspergillus nidulans. To understand the possible cellular processes in which Nek2 participates during the cell cycle, we investigated the expression and subcellular localization of Nek2 in mitotic cells. The Nek2 protein levels were observed to be regulated in a cell cycle stage-specific manner in cultured cells. The cell cycle stage specificity of Nek2 expression was also confirmed in cells undergoing mitosis in vivo. Nek2 proteins were localized in both the nucleus and cytoplasm throughout the cell cycle, but exhibited dynamic changes in distribution, depending on the cell cycle stage. Nek2 was associated with chromosomes from prophase to metaphase and then was dissociated upon entering into anaphase. Nek2 then appeared at the midbody of the cytoplasmic bridge at telophase. Nek2 was also associated with the centrosome throughout the cell cycle as observed previously by others. Additionally, the nuclear localization of Nek2 was increased during S phase. Such dynamic behavior of Nek2 suggests that Nek2 may be a mitotic regulator that is involved in diverse cell cycle events.

Diffusivity of oxygen in microvascular beds as determined from PO2 distribution maps.

Dynamic changes in the distribution of PO2 in the rat mesentery were measured to determine the O2 diffusion coefficient (DO2) and consumption rate (VO2). The distribution of PO2 was obtained in two-dimensional maps by microscopic fluorometry on the basis of oxygen quenching. The corresponding vasculature was also recorded on a video recorder to analyze the PO2 distribution consistent with the arrangement of the microvessels. Anesthetized rats breathing room air were subjected to 100% O2 ventilation to induce dynamic changes in PO2 distribution. We assumed a homogenous and constant VO2 in the tissue, and a one-dimensional diffusion equation was applied to simulate oxygen transport. The PO2 data corresponded very well to the theoretical curves, and calculated DO2 was 1.04 +/- 0.78 X 10(-5) cm2/s (mean +/- SD, n = 38) and VO2 was 8.2 +/- 3.9 x 10(-6) cm3 O2.cm-3 tissue.s-1 (n = 27) at 37 degrees C. However, PO2 values at points remote from the arterioles remained higher than the theoretical prediction.

Dynamic changes in Rad51 distribution on chromatin during meiosis in male and female vertebrates

Antibodies against human Rad51 protein were used to examine the distribution of Rad51 on meiotic chromatin in mouse spermatocytes and oocytes as well as chicken oocytes during sequential stages of meiosis. We observed the following dynamic changes in distribution of Rad51 during meiosis: (1) in early leptotene nuclei there are multiple, apparently randomly distributed, foci that by late leptonema become organized into tracks of foci. (2) These foci persist into zygonema, but most foci are now localized on Rad51-positive axes that correspond to lateral elements of the synaptonemal complex. As homologs synapse foci from homologous axes fuse. The distribution and involvement of Rad51 foci as contact points between homologs suggest that they may be components to early recombination nodules. (3) As pachynema progresses the number of foci drops dramatically; the temporal occurrence (mice) and physical and numerical distribution of foci on axes (chickens) suggest that they may be a component of late recombination nodules. (4) In early pachynema there are numerous Rad51 foci on the single axis of the X (mouse spermatocytes) or the Z (chicken oocytes) chromosomes that neither pair, nor recombine. (5) In late pachynema in mouse spermatocytes, but not oocytes, the Rad51 signal is preferentially enhanced at both ends of all the bivalents. As bivalents in spermatocytes, but not oocytes, begin to desynapse at diplonema they are often held together at these Rad51-positive termini. These observations parallel observations that recombination rates are exceptionally high near chromosome ends in male but not female eutherian mammals. (6) From diakinesis through metaphase I, Rad51 protein is detected as low-intensity fluorescent doublets that localize with CREST-specific antigens (kinetochores), suggesting that Rad51 participates, at least as a structural component of the materials involved, in sister kinetochore cohesiveness. Finally, the changes in Rad51 distribution during meiosis do not appear to be species specific, but intrinsic to the meiotic process.

Mitochondrially Encoded 16S Large Ribosomal RNA Is Concentrated in the Posterior Polar Plasm of Early Drosophila Embryos but Is Not Required for Pole Cell Formation

In a molecular screen for polar-localized RNAs in Drosophila, we identified the mitochondrially encoded 16S large ribosomal RNA (16S RNA) as an RNA that is highly concentrated at the posterior pole of early embryos. This high posterior accumulation decreases sharply during the first hour of embryogenesis and reaches the uniform level found throughout the remainder of the embryo by the time pole cells form 1.5 hr after fertilization. At the cellular blastoderm stage the 16S RNA is uniformly distributed basal to the nuclei of all somatic cells and is present only at low levels in the pole cells and in the apical regions of the somatic cells. Transcripts produced by the 12S small rRNA gene are also concentrated in the posterior polar plasm and exhibit the same dynamic changes in distribution as the 16S RNA. In contrast, NADH dehydrogenase subunit 1 RNA, which is transcribed from the same strand of the mitochondrial genome just downstream of the 12S and 16S genes, does not exhibit a high posterior concentration but is uniformly distributed throughout early embryos. Posterior localization of 16S RNA is normal in embryos produced by mothers carrying mutations which affect posterior patterning without disrupting the polar plasm or polar granule integrity. However, posterior localization of 16S RNA is abolished in embryos produced by females carrying maternal-effect mutations that disrupt the posterior polar plasm and the polar granules. Ectopic localization of the oskar RNA to the anterior pole of the oocyte and early embryo results in anterior assembly of polar plasm and anterior budding of functional pole cells. We show that 16S and 12S RNAs are not concentrated at the anterior pole of such embryos. This leads to the conclusion that, although the 16S and 12S RNAs are concentrated in the posterior polar plasm during normal development, functional pole cells can form in the absence of high levels of these RNAs. These data argue against previous hypotheses that the 16S RNA serves an obligatory function in pole cell formation.

Osmotic Adjustment and Dynamic Changes in Distribution of Low Molecular Weight Solutes Between Cellular Compartments of Carrot and Beet Root Cells Exposed to Salinity

Carrot cells (Daucus carota L.) in suspension culture exposed to medium containing 150 mM NaCl plasmolyzed immediately and deplasmolyzed within 35 to 40 hr. Three days after exposure to NaCl the cells resumed proliferation. Accommodation to salinity and renewal of growth was accompanied by absorption of Na+ from the external medium. On completion of deplasmolysis, K+ concentration in the cytosol doubled and Na+ concentration approximated that of K+. The vacuolar K+ concentration was practically unchanged while Na+ accumulated to a concentration double that of K+. Cl−- accumulation started later and eventually exceeded that of Na+ plus K+. Malate was redistributed during accommodation to salinity and eventually returned to its initial level. Amino acid content in the cytosol increased fivefold, while in the vacuole it remained unchanged. These results show that: 1) recovery from osmotic shock requires absorption of easily penetrating solute, mainly Na+; 2) distribution of solutes, absorbed or synthesized in cells exposed to salinity, is a dynamic process; 3) cells could grow and proliferate in high NaCl content in the cytosol; 4) red beet root cells grown in the presence of NaCl contain higher cytoplasmic Na+ than K+; and 5) during adjustment to salinity small spherical carrot cells survive the osmotic shock and do not show any detectable damage.