Structural Changes Research Articles

Astragaloside IV Protects Against IL-1β-Induced Chondrocyte Damage via Activating Autophagy.

Osteoarthritis (OA) is a chronic inflammatory condition that affects the articular cartilage. Astragaloside IV (AS-IV) constitutes the primary active component of the Chinese herbal medicine Huangqi (Radix Astragali Mongolici). AS-IV demonstrates anti-inflammatory and anti-apoptotic attributes, exhibiting therapeutic potential across various inflammatory and apoptosis-related disorders. Nevertheless, its pharmaceutical effects in OA are yet to be fully defined. This study aimed to investigate the protective impact of AS-IV on rat chondrocytes treated with IL-1β and ascertain whether autophagy plays a role in this effect. Chondrocytes were isolated and cultivated from the knee joints of neonatal SD mice. The study included the blank control group, the model group, and the AS-IV concentration gradient group (50, 100, 200 μmol/L) to intervene with chondrocytes. The MTT assay was employed to assess cell viability at varying culture periods, enabling the determination of suitable concentration and duration. Subsequently, chondrocytes were treated with the optimal AS-IV concentration and divided into three groups: the model group replicated IL-1β-induced inflammatory chondrocyte injury, the AS-IV group received a co-culture of AS-IV and IL-1β, and a blank control group was established. Changes in cell morphology and structure were observed using ghost pen cyclic peptide staining. ELISA was used to measure TNF-α and GAG levels in cell supernatants. RT-qPCR assessed p62 and LC3 mRNA expression, while Western Blot evaluated p62 and LC3Ⅱ/Ⅰ protein expression. AS-IV promoted chondrocyte proliferation and concurrently inhibited cell apoptosis. An optimal AS-IV dose of 200 μmol/L and a suitable reaction time of 48 h were identified. Ghost pen cyclic peptide staining indicated that the model group's cytoskeleton exhibited fusiform changes with reduced immunofluorescence intensity, as opposed to the blank control group. The AS-IV group displayed more polygonal cytoskeletal morphology with increased immunofluorescence intensity. AS-IV reduced TNF-α levels and elevated GAG levels in the culture supernatant. Additionally, AS-IV lowered p62 mRNA and protein expression while increasing LC3 mRNA expression in cultured chondrocytes. Our findings suggest that AS-IV mitigates inflammatory chondrocyte injury, safeguarding chondrocytes through a potential autophagy suppression mechanism. These results imply that AS-IV could offer preventive advantages for OA.

Learning Optimizer-Based Visual Analytics Method to Detect Targets in Autonomous Unmanned Aerial Vehicles

Visual analytics is vital for identifying targets by differentiating their structure and texture from unmanned aerial vehicles (UAVs). Object sensing disturbance and swift texture differentiation are tedious due to the UAV displacements. For improving the accuracy of target detection, this article introduces a learning optimizer-based visual analytics method. The proposed method assimilates deep learning and a gradient descent algorithm for feature differentiation and error minimization concurrently. The captured images are identified using multiple structural feature variations and are correlated with similar stored images. The features are extracted at different displacement and structural changing instances for leveraging accuracy. The learning process trains the similarity features during different differentiation factors. In the feature extraction, the minimum slope points are identified using a gradient descent algorithm by assigning random weights. As the differentiation increases using similar features, the minimum similarity value is detection. Postdetection, the weights are incremental and linear across different feature slopes. Therefore, the accuracy increases under varying displacement instances, preventing target misdetection. The gradient function is invariable between the minimum and maximum values for identifying high-precision features. This ensures optimal detection of different buildings and structures with high accuracy.

The Possible Protective Effect of Taurine on Bisphenol Induced Structural Changes on the Cerebral Cortex of Rats: Histological and Immunohistochemical Study.

Bisphenol A (BPA) is a chemical compound that has been used in many industries, such as paints and dental sealants. Taurine is a semi-essential amino acid with antioxidant, anti-inflammatory, and anti-apoptotic actions. This study aimed to evaluate the possible protective effect of taurine on BPA-induced structural changes in the cerebral cortex of rats using histological and immunohistochemical methods. 35 Wistar rats (180-200 gm) were divided into control: 10 rats; Group I: 5 rats received corn oil (0.5 mL/day); Group II (Bisphenol low dose; BPAL): 5 rats received a low dose of BPA (25 mg/kg/three times/week); Group III (Bisphenol high dose; BPAH): 5 rats received a high dose of BPA (100 mg/kg/three times/week; Group IV: (BPAL + taurine): 5 rats received taurine 100 mg/kg/day and BPAL (25 mg/kg/three times/week); Group V: (BPAH + taurine): 5 rats received taurine 100 mg/kg/day and BPH (100 mg/kg/ three times/week). BPAL& BPAH groups showed significant dose-dependent histological changes of the neuropil, pyramidal, and neuroglial cells at H&E stained sections, significantly increased GFAP, caspase- 3 immunohistochemical reaction with cells positive for Ki67 with many mitotic figures. BPAL + taurine and BPAH + taurine groups showed amelioration of the previously mentioned results. Taurine ameliorated the structural changes induced by BPA in the cerebral cortex of rats.

Biological action of bleaching agents on tooth structure: A review.

The use of bleaching agents to remove stains is one of the main dental procedures to improve the aesthetics of teeth. This review presents the main agents used for tooth whitening, existing clinical protocols, and the structural changes that may occur through their use. The main bleaching agents consist of hydrogen peroxide and carbamide peroxide, which are used in bleaching techniques for vital teeth. These techniques can be performed in the office by a professional or by the individual in a home en-vironment under professional guidance. Bleaching agents come in a variety of concentrations and there are over-the-counter products available on the market with lower concentrations of hydrogen peroxide. Due to the chemical characteristics of the agents, changes in the organic and inorganic content of the tooth structure can be observed. These changes are related to morphological changes characterized by in-creased permeability and surface roughness, such changes compromise the mechanical resistance of the tooth. Furthermore, bleaching agents can promote molecular changes after reaching the dental pulp, resulting in oxidative stress of pulp cells and the release of pro-inflammatory mediators. Despite the bleaching effectiveness, tooth sensitivity is considered the main side effect of use. Therefore, among the heterogeneity of protocols, those that used the bleaching agent for a prolonged time and in lower con-centrations presented more harmful effects on the tooth structure.

Eagle’s syndrome: Modern systematic review and presentation of radiographic cases

Introduction: The styloid process is a bony structure of the base of the skull, which can undergo pathological structural changes. So, its elongation may possibly provoke Eagle’s syndrome, also known as stylohyoid syndrome, which is a head and neck pathological condition that rarely manifests with severely painful symptomatology. Objective: The present literature review aims to deal with the understanding of the pathophysiology, as well as the investigation of the diagnostic and therapeutic facts regarding Eagle’s syndrome. Materials – Methods: An extended research of modern literature through papers published in scientific journals has been conducted, deploying the databases PubMed and Google Scholar. Results: Eagle’s syndrome is a rare pathological condition, whose prevalence is approximately 4% of general population. In the literature, several pathogenetic patterns have been reported and they are divided into acquired and idiopathic biochemical mechanisms. In order to diagnose the disease, one should take the painful symptoms referred by the patient into consideration, in conjunction with specific clinical tests. However, the final diagnosis is set after the radiological evaluation. Eagle’s syndrome manifests with non-specific symptomatology, thus it should be differentiated from other diseases and conditions of the head and neck anatomical area. Regarding the therapy of the syndrome, a vast range of conservative choices is available nowadays, mainly basedon drugs, while at the same time there are surgical techniques with comparatively better long-term outcome. Conclusions: There is an expressively increased interest, regarding the diagnosis and the therapeutics of Eagle’s syndrome. Modern medical sciences attempt to gradually advance the diagnostic methodology and constantly improve the therapeutic choices of this disease. The ultimate purpose is the more effective management of the patients and the enhancement of their life quality.

Association of Arterial Stiffness Index and Brain Structure in the UK Biobank: A 10-Year Retrospective Analysis.

Arterial stiffening and changes in brain structure both occur with normal aging and can be exacerbated via acquired health conditions. While cross-sectional associations exist, the longitudinal relationship between arterial stiffness and brain structure remains unclear. In this study, we investigated 1) associations between baseline arterial stiffness index (ASI) and brain structure (global and regional grey matter volumes (GMV), white matter hyperintensities (WMH)) 10-years post-baseline (10.4±0.8 years) and 2) associations between the 10-year change in ASI from baseline and brain structure 10-years post-baseline in 650 healthy middle- to older-aged adults (53.4±7.5 years) from the UK Biobank. We observed significant associations between baseline ASI and GMV (p<0.001) and WMH (p=0.0036) 10-years post-baseline. No significant associations between 10-year change in ASI and brain structure (global GMV p=0.24; WMH volume p=0.87) were observed. There were significant associations of baseline ASI in 2 of 60 regional brain volumes analyzed (right posterior superior temporal gyrus p=0.001; left superior lateral occipital cortex p<0.001). Strong associations with baseline ASI, but not changes in ASI over 10-years, suggest arterial stiffness at the entry point of older adulthood is more impactful on brain structure 10-years later compared to age-related stiffening. Based on these associations, we suggest clinical monitoring and potential intervention for reducing arterial stiffness should occur in midlife to reduce vascular contributions to structural changes in the brain, supporting a healthy trajectory of brain aging. Our findings also support use of ASI as a surrogate for gold standard measures in showing overall relationships between arterial stiffness and brain structure.

Kidney Injury: Focus on Molecular Signaling Pathways.

Acute kidney injury (AKI) is a syndrome in which kidney function reduces suddenly. This syndrome which includes both structural changes and loss of function may lead to chronic kidney disease (CKD). Kidney regeneration capacity depends on the cell type and severity of the injury. However, novel studies indicated that regeneration mostly relies on endogenous tubular cells that survive after AKI. Regenerative pharmacology requires a great knowledge of fundamental processes involved in the development and endogenous regeneration, leading to a necessity for investigating related signaling molecules in this process. Regulatory non-coding RNAs (ncRNAs) including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) are currently known as critical regulators of gene expression in various cellular processes, and this regulatory function is also observed in nephrotic tissue, following damaging insults, which may promote or inhibit the progression of damage. Thus, studying signaling molecules and pathways involved in renal injury and repair results in a comprehensive prospect of these processes. Moreover, these studies can lead to new opportunities for discovering and enhancing therapeutic approaches to renal diseases. Herein, we review studies dealing with the role of different signaling pathways involved in renal injury. Besides, we discuss how some signaling pathways are useful for the repair process following AKI.

Changing placements: A punctuated equilibrium model of work-family role boundary reconstruction.

In the face of changes to the work-family environment, the ability to manage role boundaries may be threatened. Drawing on punctuated equilibrium models of system change and cognitive dissonance theory, we extend boundary theory through a conceptual model that explains how and when individuals may tear down and rebuild work and family role boundaries in the mind in order to maintain well-being. We argue that divergent events compel individuals to enact role boundaries inconsistent with those held internally in the mind, resulting in cognitive dissonance. We further argue that high levels of cognitive dissonance past a threshold may trigger a revolutionary change in the deep structure of one's internally drawn role boundaries, resulting in a significant change in the extent to which work and family roles are cognitively segmented or integrated. We also argue that change events that generate lower levels of cognitive dissonance can be mitigated with boundary management tactics that create only incremental changes to work and family role boundaries. Our model advances a dynamic perspective of boundary theory that returns focus to the boundary placement process, which is often overlooked in work-family research. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Changes in physical fitness and body build of women and men surveyed in 2004 and 2022-A longitudinal study.

Physical fitness plays a crucial role in determining human health and overall well-being. The objective of the study was to assess the changes in body structure and physical fitness among individuals examined in 2004 and 2022 (persons aged 32-34 and 50-52). The research material consists of data from the Krakow Continuous Study (KCS) of somatic development and physical fitness of people born in 1970 and 1972, conducted in Krakow in the years 1976-2022. In total, in 2004, 103 women and 122 men took part in the study, and in 2022-47 women and 67 men. Of these participants, 37 women and 53 men were present for both measurements. The following measurements were performed-physical fitness tests: handgrip strength of left and right hand, standing broad jump, sit-and-reach test and overhead medicine ball throw (2 kg); anthropometric measurements: body height, body weight and tissue composition, circumferences of the chest (relaxed and in deep inspiration), waist, hips, thigh, mid-upper-arm (MUAC, relaxed and in deep inspiration), forearm and calf, thickness of biceps, triceps, subscapular, abdominal, suprailiac and calf skinfolds; width of shoulders and hips, depth and width of the chest. A comparative analysis of the two series showed that all fitness test scores deteriorated. The percentage decrease was greater in women than in men in the tests of right and left handgrip strength and overhead medicine ball throw than in men, in the standing broad jump test similar in both sexes, in the sit-and-reach test-lower in women than in men. The greatest decreases were observed in the standing broad jump (by 14%) and the 2 kg medicine ball throw (15-12%), both in women and men. In contrast, the level of development of most of the somatic characteristics studied in 2022 was higher compared to the previous study, and, apart from body height, elbow and knee width and calf skinfold in both sexes, the differences in arithmetic means between the 2004 and 2022 series were statistically significant. Furthermore, the absence of involutionary changes in body height can be highlighted. In conclusion, the decrease in physical fitness occurring in adulthood and the increase in most somatic characteristics between 32 and 34 year-olds and 50 and 52 year-olds were confirmed.

Reorganization of the Flagellum Scaffolding Induces a Sperm Standstill During Fertilization.

In this work, we demonstrate that the helical structure of polymerized actin in the flagellum undergoes a rearrangement at the time of sperm-egg fusion. This process is driven by intracellular calcium and promotes a decrease in the sperm midpiece diameter as well as the arrest in motility, which is observed after the fusion process is initiated.

Anesthetic Mechanisms: Synergistic Interactions With Lipid Rafts and Voltage-Gated Sodium Channels.

Despite successfully utilizing anesthetics for over 150 years, the mechanism of action remains relatively unknown. Recent studies have shown promising results, but due to the complex interactions between anesthetics and their targets, there remains a clear need for further mechanistic research. We know that lipophilicity is directly connected to anesthetic potency since lipid solubility relates to anesthetic partition into the membrane. However, clinically relevant concentrations of anesthetics do not significantly affect lipid bilayers but continue to influence various molecular targets. Lipid rafts are derived from liquid-ordered phases of the plasma membrane that contain increased concentrations of cholesterol and sphingomyelin and act as staging platforms for membrane proteins, including ion channels. Although anesthetics do not perturb membranes at clinically relevant concentrations, they have recently been shown to target lipid rafts. In this review, we summarize current research on how different types of anesthetics-local, inhalational, and intravenous-bind and affect both lipid rafts and voltage-gated sodium channels, one of their major targets, and how those effects synergize to cause anesthesia and analgesia. Local anesthetics block voltage-gated sodium channel pores while also disrupting lipid packing in ordered membranes. Inhalational anesthetics bind to the channel pore and the voltage-sensing domain while causing an increase in the number, size, and diameter of lipid rafts. Intravenous anesthetics bind to the channel primarily at the voltage-sensing domain and the selectivity filter, while causing lipid raft perturbation. These changes in lipid nanodomain structure possibly give proteins access to substrates that have translocated as a result of these structural alterations, resulting in lipid-driven anesthesia. Overall, anesthetics can impact channel activity either through direct interaction with the channel, indirectly through the lipid raft, or both. Together, these result in decreased sodium ion flux into the cell, disrupting action potentials and producing anesthetic effects. However, more research is needed to elucidate the indirect mechanisms associated with channel disruption through the lipid raft, as not much is known about anionic lipid products and their influence over voltage-gated sodium channels. Anesthetics' effect on S-palmitoylation, a promising mechanism for direct and indirect influence over voltage-gated sodium channels, is another auspicious avenue of research. Understanding the mechanisms of different types of anesthetics will allow anesthesiologists greater flexibility and more specificity when treating patients.

Dynamics of deposit dollarization in Turkey

&lt;p style="text-align:justify"&gt;&lt;span style="font-size:16px"&gt;&lt;span style="font-family:Times New Roman,Times,serif"&gt;&lt;span dir="ltr" lang="EN-US"&gt;&lt;span style="color:black"&gt;Deposit dollarization in Turkey has been on the rise, reaching record levels in 2022. This was caused by the worsening macroeconomic fundamentals along with the transition to the presidential system in 2018 and the associated deviation from the monetary policy stance afterward. The unique case of Turkey presents an excellent natural experiment to explore the dynamics of deposit dollarization and how it is affected by the changes in the institutional structure as well as various social, economic, and financial shocks in a relatively short time. This study examines the time varying reactions of deposit dollarization for the period between 2013 and 2022 based on rolling window maximum entropy bootstrap estimates. Our findings reveal that all the model variables had significant and sometimes asymmetric effects on deposit dollarization during the different stages of this turbulent period. In particular, we observe diminishing effects of real exchange rate, policy credibility and consumer confidence over time. The findings provide ample new evidence regarding the dynamics of deposit dollarization in general, and how it is affected by loss of monetary policy credibility.&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;

3D Mitochondrial Structure in Aging Human Skeletal Muscle: Insights into MFN-2 Mediated Changes.

Age-related atrophy of skeletal muscle, is characterized by loss of mass, strength, endurance, and oxidative capacity during aging. Notably, bioenergetics and protein turnover studies have shown that mitochondria mediate this decline in function. Although exercise has been the only therapy to mitigate sarcopenia, the mechanisms that govern how exercise serves to promote healthy muscle aging are unclear. Mitochondrial aging is associated with decreased mitochondrial capacity, so we sought to investigate how aging affects mitochondrial structure and potential age-related regulators. Specifically, the three-dimensional (3D) mitochondrial structure associated with morphological changes in skeletal muscle during aging requires further elucidation. We hypothesized that aging causes structural remodeling of mitochondrial 3D architecture representative of dysfunction, and this effect is mitigated by exercise. We used serial block-face scanning electron microscopy to image human skeletal tissue samples, followed by manual contour tracing using Amira software for 3D reconstruction and subsequent analysis of mitochondria. We then applied a rigorous in vitro and in vivo exercise regimen during aging. Across 5 human cohorts, we correlate differences in magnetic resonance imaging, mitochondria 3D structure, exercise parameters, and plasma immune markers between young (under 50 years) and old (over 50 years) individuals. We found that mitochondria we less spherical and more complex, indicating age-related declines in contact site capacity. Additionally, aged samples showed a larger volume phenotype in both female and male humans, indicating potential mitochondrial swelling. Concomitantly, muscle area, exercise capacity, and mitochondrial dynamic proteins showed age-related losses. Exercise stimulation restored mitofusin 2 (MFN2), one such of these mitochondrial dynamic proteins, which we show is required for the integrity of mitochondrial structure. Furthermore, we show that this pathway is evolutionarily conserved as Marf, the MFN2 ortholog in Drosophila, knockdown alters mitochondrial morphology and leads to the downregulation of genes regulating mitochondrial processes. Our results define age-related structural changes in mitochondria and further suggest that exercise may mitigate age-related structural decline through modulation of mitofusin 2.

Molecular Mechanism of Tau Misfolding and Aggregation: Insights from Molecular Dynamics Simulation.

Tau dysfunction has a close association with many neurodegenerative diseases, which are collectively referred to as tauopathies. Neurofibrillary tangles (NFTs) formed by misfolding and aggregation of tau are the main pathological process of tauopathy. Therefore, uncovering the misfolding and aggregation mechanism of tau protein will help to reveal the pathogenic mechanism of tauopathies. Molecular dynamics (MD) simulation is well suited for studying the dynamic process of protein structure changes. It provides detailed information on protein structure changes over time at the atomic resolution. At the same time, MD simulation can also simulate various conditions conveniently. Based on these advantages, MD simulations are widely used to study conformational transition problems such as protein misfolding and aggregation. Here, we summarized the structural features of tau, the factors affecting its misfolding and aggregation, and the applications of MD simulations in the study of tau misfolding and aggregation.

Effects of coating formulation on structural changes of turkey nugget during frying: MRI evaluation

Effects of coating formulation on structural changes of turkey nugget during frying: MRI evaluation

Stereo-Structural Fine Tuning of Chromaticity.

Lanthanoid carboxylates were synthesized and in situ self-assembled to illustrate temperature-driven evolution in chromaticity. Evolution in structure (crystallinity), composition, luminosity, and chromaticity were investigated revealing the coupled role of divergence in order/structure (spatial organization), and composition in tuning observed color. Loss of crystallinity or increase in residual carbon leads to decrease in luminosity even with increase in hue. Comparing Ho and Er congeners shows that the density of accessible transition states relates to shifts in low and high wavelength components of color. This work demonstrates that, just as interface dipoles can lead to change in semiconductor band gap, structure and composition can analogously alter observed color.

The protective role of phlorizin against lipopolysaccharide-induced acute orchitis in mice associated with changes in gut microbiota composition

ObjectiveOrchitis is a common reproductive disease of male animals, which has serious implications to human and animal reproduction. Additionally, phlorizin (PHN), a common polyphenol in apples and strawberries, has a variety of biological activities, including antioxidant, anti-inflammatory, anti-diabetic, and anti-aging activities. We aimed to determine the protective effects and potential mechanisms of PHN in lipopolysaccharide (LPS)-induced acute orchitis in mice.MethodAfter 21 days of PHN pretreatment, mice were injected with LPS to induce testicular inflammation, and then the changes of testicular tissue structure, expression of inflammatory factors, testosterone level, expression of testosterone-related genes, adhesion gene and protein expression were detected, and the structural changes in the intestinal flora after PHN treatment were further detected by 16SRNA.ResultOur results demonstrated that PHN treatment reduced LPS-induced testicular injury and body and testicular weight losses. The mRNA expression levels of pro-inflammatory cytokines-related genes and antioxidant enzyme activity were also decreased and elevated, respectively, by PHN administration; however, PHN treatment also reduced the LPS-induced decrease in testosterone levels in the testes. Additionally, further studies found that PHN increased the expression of marker proteins zonula occludens-1 (ZO-1) and occludin associated with the blood testosterone barrier compared with that in LPS treatment groups. To further examine the potential mechanisms of the protective effect of PHN on LPS-induced testicular injury, we compared the differences of gut microbiota compositions between the 100 mg/kg PHN treatment group and the control group using 16SRNA. Metagenomic analyses indicated that the abundances of Bacteroidetes, Muribaculaceae, Lactobacillaceae, uncultured bacterium f Muribaculaceae, and Lactobacillus in the PHN treatment group improved, while potential microbes that can induce intestinal diseases, including Verrucomicrobia, Epsilonbacteraeota, Akkermansiaceae, and Akkermansia decreased in the PHN treatment group.ConclusionOur results indicate that PHN pretreatment might alleviate orchitis by altering the composition of gut microflora, which may provide a reference for reducing the occurrence of acute orchitis in male animals.

Transition to a weaker Sun: Changes in the solar atmosphere during the decay of the Modern Maximum

Context.The Sun experienced a period of unprecedented activity during the 20th century, now called the Modern Maximum (MM). The decay of the MM after its maximum in cycle 19 has changed the Sun, the heliosphere, and the planetary environments in many ways. However, studies disagree on whether this decay has proceeded synchronously in different solar parameters or not.Aims.One of the related key issues is if the relation between two long parameters of solar activity, the sunspot number and the solar 10.7 cm radio flux, has remained the same during this decay. A recent study argues that there is an inhomogeneity in the 10.7 cm radio flux in 1980, which leads to a step-like jump (“1980 jump”) in this relation. If true, this result would reduce the versatility of possible long-term studies of the Sun during the MM. Here we aim to show that the relation between sunspot number and 10.7 cm radio flux does indeed vary in time, not due to an inhomogeneous radio flux but due to physical changes in the solar atmosphere.Methods.We used radio flux measurements made in Japan at four different wavelengths, and studied their long-term relation with the sunspot number and the 10.7 cm radio flux during the decay of MM. We also used two other solar parameters, the MgII index and the number of solar active regions, in order to study the nature of the observed long-term changes in more detail.Results.We find that the 1980 jump is only the first of a series of 1–2-year “humps” that mainly occur during solar maxima. All five radio fluxes depict an increasing trend with respect to the sunspot number from the 1970s to 2010s. These results exclude the interpretation of the 1980 jump as an inhomogeneity in the 10.7 cm flux, and reestablish the 10.7 cm flux as a homogeneous measure of solar activity. The fluxes of the longer radio waves are found to increase with respect to the shorter waves, which suggests a long-term change in the solar radio spectrum. We also find that the MgII index of solar UV irradiance and the number of active regions also increased with respect to the sunspot number, further verifying the difference in the long-term evolution in chromospheric and photospheric parameters.Conclusions.Our results provide evidence for important structural changes in solar magnetic fields and the solar atmosphere during the decay of the MM, which have not been reliably documented so far. We also emphasize that the changing relation between the different (e.g., photospheric and chromospheric) solar parameters should be taken into account when using the sunspot number or any single parameter in long-term studies of solar activity.

Blood glucose-lowering activity of protocatechuic acid is mediated by inhibiting α-glucosidase

α-Glucosidase inhibitors are effective in controlling postprandial hyperglycemia, which play crucial roles in the management of type 2 diabetes. Protocatechuic acid (PCA) is one of phenolic acids existing not only in various plant foods but also as a major microbial metabolite of dietary anthocyanins in the large colon. The present study investigated the inhibitory mechanism of PCA on α-glucosidase in vitro and examined its effect on postprandial blood glucose levels in vivo. Results from in vitro experiments demonstrated that PCA was a mix-type inhibitor of α-glucosidase. Driven by hydrogen bonds and van der Waals interactions, PCA reversibly bound with α-glucosidase to form a stable α-glucosidase-PCA complex in a spontaneous manner. The computational simulation found that PCA could insert into the active cavity of α-glucosidase and establish hydrogen bonds with catalytic amino acid residues. PCA binding aroused the steric hindrance for substrates to enter active sites and caused the structural changes of interacted catalytic amino acid residues. PCA also exhibited postprandial hypoglycemic capacity in diabetic mice. This study may provide the theoretical basis for the application of PCA as an active ingredient of functional foods in dietary management of diabetes.

Bilingual Language Control in the Brain: Evidence from Structural and Effective Functional Brain Connectivity.

Experience in bilingual language control is often accompanied by changes in the structure and function of the brain. Brain structural changes are also often closely related to changes in functions. Previous studies, however, have not directly explored the relationship between structural connectivity and effective functional connectivity of the brain during bilingual language control, and whether the two types of connectivity are associated with behavioral performance of language control. Using behavioral performance, functional, and diffusion imaging techniques, we found that: (1) during language control, the left dorsal lateral prefrontal cortex (dlPFC), left caudate nucleus (CN), inferior parietal lobe, precuneus, and dorsal anterior cingulate cortex (dACC)/pre-SMA were significantly activated. (2) In the language control model with left dlPFC, dACC/pre-SMA, and left CN as ROIs (selected based on activation results and language control models from previous studies), stimuli first enter dACC/pre-SMA and then to left CN. At the left CN, a bidirectional effective connectivity is formed with left dlPFC. (3) There is a nonlinear relationship between effective connectivity during language control and the structural connectivity of the second language learners' brains. Specifically, the fiber density between dACC/pre-SMA and left dlPFC has a positive influence on the bidirectional effective connectivity between left dlPFC and left CN. Findings of the present study contribute evidence toward functional effective connectivity during bilingual language control; toward structural connectivity in the brains of second language learners; as well as toward nonlinear relationships between functional effective connectivity, structural connectivity, and behavioral performance in relation to bilingual language control.