Bidirectional Effect Research Articles

Multi-scale modeling and simulation of bidirectional coupled moisture and heat transfer in concrete

The change of humidity and temperature field of concrete is closely related to its long-term time-varying performance of shrinkage and creep. Therefore, accurate prediction of temperature and humidity in concrete plays an important role in studying the service performance of concrete structures. In the study, the mechanism of coupled moisture and heat (M&H) transfer in concrete is systematically analyzed from three scales: micro-nano scale, mesoscale, and macroscale; meanwhile, a multi-scale theoretical model of coupled M&H transfer in concrete is established. In addition, a novel simulation method of bidirectional coupled of M&H is proposed and the corresponding ABAQUS subroutine is compiled. Based on the existing experiments, the concrete temperature and humidity data for 180 days were further monitored, which verified the feasibility of the proposed method. Finally, the prediction results of M&H transfer are analyzed and compared in three cases: uncoupling, unidirectional coupling, and bidirectional coupling. For the temperature prediction, the early hydration temperature rise is underestimated under the uncoupled model and the unidirectional coupled model that only considering the influence of temperature on humidity, and the prediction error of unidirectional coupled model that only considering the influence of humidity on temperature is relatively small. For the humidity prediction, both uncoupled and unidirectional coupled models underestimate the water consumption, and the closer to the surface of the concrete, the greater the error. Through experiments and numerical simulation analysis, it is suggested that the bidirectional coupled effect should be considered in the analysis of wet-heat field of concrete. This study provides a new way for the modeling and simulation of coupled M&H of concrete, and lays the foundation for the long-term performance research of infrastructure.

Identifying the mediating role of socioeconomic status on the relationship between schizophrenia and major depressive disorder: a Mendelian randomisation analysis

Depressive disorder prevalence in patients with schizophrenia has been reported to be 40%. People with low socioeconomic status (SES) are more likely to suffer from schizophrenia and major depressive disorder (MDD). However, the causal relationship between schizophrenia and depression and the potential mediating role of SES remains unclear. Two-sample Mendelian randomization (MR) analyses were conducted to explore the bidirectional causal relationship between schizophrenia and MDD with the largest sample size of European ancestry from public genome-wide association studies (sample size ranged from 130,644 to 480,359). Inverse variance weighted (IVW) method was used as the primary analysis, and several canonical MR methods were used as validation analyses. The mediating role of SES (educational years, household income, employment status, and Townsend deprivation index) was estimated by the two-step MR method. MR analyses showed that genetically predicted schizophrenia was associated with an increased risk of MDD (IVW odds ratio [OR] = 1.137 [95% CI 1.095, 1.181]). Reversely, MDD was also associated with an increased risk of schizophrenia (IVW OR = 1.323 [95% CI 1.118, 1.565]). The mediation analysis via the two-step MR method revealed that the causal effect of schizophrenia on MDD was partly mediated by the Townsend deprivation index with a proportion of 10.27%, but no significant mediation effect was found of SES on the causal effect of MDD on schizophrenia. These results suggest a robust bidirectional causal effect between schizophrenia and MDD. Patients with schizophrenia could benefit from the early and effective intervention of the Townsend deprivation index.

Body Movements During Maladaptive Daydreaming

Objectives: This study aimed to shed light on the lived experience of stereotypical body movement and gesturing during maladaptive daydreaming (MD). Method: Forty-one individuals with probable MD participated in asynchronous in-depth email interviews. Results: Four themes describing the movement experience in MD emerged: Need, Variety, Awareness and Agency, and Functions. The analysis revealed two main findings about the bi-directional effect of movement on MD. First, kinesthesia might enhance the daydreamers’ experience by deepening their fantasy immersion through improved focus featuring self-hypnotic characteristics. In addition, respondents reported that their body movements enhanced the daydreaming experience by embodying the protagonists' actions. MD-related motions were associated with occasional loss of agency, suggesting unintentional neuromuscular activation.

Pedestrian delay models for compliant & non-compliant behaviour at signalized midblock crosswalks under mixed traffic conditions

The present study aimed to propose new pedestrian delay models for Signalized Midblock Crosswalks (SMC) for mixed traffic conditions. A detailed study of the literature revealed that most of the existing pedestrian delay models were developed for signalized intersections. Thus, the need for the study was established and data were collected at eight SMC in Hyderabad, one of the most densely populated metropolitan cities in India, using video-graphic technique. Two delay models were developed based on the compliance behaviour and non-compliance behaviour of pedestrians. Both models have two components i.e., waiting delay and crossing delay where the latter has two subset components i.e., frictional delay and pedestrian-vehicle interaction delay. The bidirectional effect (pedestrian-pedestrian interaction while crossing the road) of pedestrians was addressed as frictional delay while the non-compliance behaviour by pedestrians and vehicles was addressed as pedestrian-vehicle interaction delay in the present models. The waiting delay component was defined by modifying the Webster delay model for non-uniform pedestrian arrivals. The proposed delay models yielded an error of 5% and 7% for compliance behaviour model and non-compliance behaviour model respectively. The proposed models can be used for optimizing the signal timings and defining Level of Service (LOS) of facilities.

The role of maternal age on adverse pregnancy outcomes among primiparous women with singleton birth: a retrospective cohort study in urban areas of China

Background Both young and advanced maternal age pregnancies have strong associations with adverse pregnancy outcomes; however, there is limited understanding of how these associations present in an urban environment in China. This study aimed to analyze the associations between maternal age and pregnancy outcomes among Chinese urban women. Methods We performed a population-based study consisting of 60,209 singleton pregnancies of primiparous women whose newborns were delivered after 20 weeks’ gestation between January 2012 and December 2015 in urban areas of China. Participants were divided into six groups (19 or younger, 20–24, 25–29, 30–34, 35–39, 40 or older). Pregnancy outcomes include gestational diabetes mellitus (GDM), preeclampsia, placental abruption, placenta previa, premature rupture of membrane (PROM), postpartum hemorrhage, preterm birth, low birthweight, small for gestational age (SGA), large for gestational age (LGA), fetal distress, congenital microtia, and fetal death. Logistic regression models were used to assess the role of maternal age on the risk of adverse pregnancy outcomes with women aged 25–29 years as the reference group. Results The risks of GDM, preeclampsia, placenta previa, and postpartum hemorrhage were decreased for women at a young maternal age and increased for women with advanced maternal age. Both young and advanced maternal age increased the risk of preterm birth and low birthweight. Young maternal age was also associated with increased risk of SGA (aOR 1.64, 95% CI 1.46–1.83) and fetal death (aOR 2.08, 95% CI 1.35–3.20). Maternal age over 40 years elevated the odds of placental abruption (aOR 3.44, 95% CI 1.47–8.03), LGA (aOR 1.47, 95% CI 1.09–1.98), fetal death (aOR 2.67, 95% CI 1.16–6.14), and congenital microtia (aOR 13.92, 95% CI 3.91–49.57). There were positive linear associations between maternal age and GDM, preeclampsia, placental abruption, placenta previa, PROM, postpartum hemorrhage, preterm birth, LGA and fetal distress (all P for linear trend < .05), and a negative linear association between maternal age and SGA (P for linear trend < .001). The analysis of the associations between maternal age and adverse fetal outcomes showed U-shape for preterm birth, low birth weight, SGA, fetal death and congenital microtia (all P for quadratic trend < .001). Conclusions Advanced maternal age predisposes women to adverse obstetric outcomes. Young maternal age manifests a bidirectional effect on adverse pregnancy outcomes. The findings may contribute to improving women’s antenatal care and management.

Identification of Breast Cancer LCK Proto-Oncogene as a Master Regulator of TNBC Neutrophil Enrichment and Polarization.

The role of neutrophils in breast cancer shows that the N1 proinflammatory subtype can suppress and attack the tumor. In contrast, the N2 pro-tumor subtype aids the tumor in its survival, progression, and metastasis. Recently, more focus has been directed to the role of innate myeloid cells, specifically neutrophils, in regulating the responses of lymphoid populations both in the progression of cancer and in response to therapy. However, the exact crosstalk between breast cancer cells and neutrophils is poorly understood. In this work, we used in-silico assays to investigate the role of the bidirectional effect of neutrophils on metastatic TNBC. Our reanalysis of publicly available data reveals that most TNBC's classified within the CE2 subtype are leukocyte-poor and have four major cell types in their ecotypes: dendritic cells, macrophages, fibroblasts, and epithelial cells. Further immune deconvolution of these patients revealed that a few cells significantly differed between groups, including macrophages, neutrophils, and T cells. All BC showed lower infiltrating neutrophils compared to healthy surrounding tissue. Treated TNBCs improved the count of infiltrating neutrophils in TNBC. Most TNBC patients have a unique CE2 ecotype, characterized by more basal-like epithelial cells, more neutrophils, and fewer mononuclear lymphocytes (B cells, macrophages M1, T cell CD4+ (non-regulatory), and T cell CD8+ and T regs). This can be related to our finding that CE2 TNBCs are characterized by a lower LCK and higher ERBB2, and their top DEGs are related to leukocyte activation and NFKB pathway.

No genetic causal association between dental caries and Alzheimer's disease: a bidirectional two-sample Mendelian randomization analysis.

An increasing number of observational studies have suggested an association between dental caries and Alzheimer's disease (AD). The association between dental caries and Alzheimer's disease may be mediated by confounders or reverse causality. In this study, we conducted bidirectional two-sample Mendelian randomization (MR) to estimate the bidirectional causality between dental caries and AD. Genome-wide association study (GWAS) summary statistics of dental caries were extracted from a published meta-analysis which included a total of 487,823 participants. GWAS datasets of AD and AD onset age were obtained from the FinnGen bank. A bidirectional two-sample analysis was performed to explore the causality between dental caries and AD. For the dental caries-AD causality estimation, there was no significant association between dental caries and AD, neither with the AD GWASs from the FinnGen database (OR: 1.041, p = 0.874) nor with those from the International Genomics of Alzheimer's Project (OR: 1.162, p = 0.409). In addition, the genetic susceptibility to dental caries was not related to the onset age of AD. No causality existed between dental caries and early-onset AD (OR: 0.515, p = 0.302) or late-onset AD (OR: 1.329, p = 0.347). For the AD-dental caries relationship, no causality was detected by the IVW method (OR: 1.000, p = 0.717). Findings from other MR methods were consistent. The pleiotropy test and sensitivity analysis confirmed the validity of these MR results. In this bidirectional MR study, robust evidence to support a bidirectional causal effect between dental caries and AD from the GWAS results within large-scale European-descent populations was absent. Having dental caries would not alter the onset age of AD.

Coupling mechanism between vegetation and multi-depth soil moisture in arid–semiarid area: Shift of dominant role from vegetation to soil moisture

Soil moisture (SM) is an essential water source for vegetation, while vegetation also exerts importance on SM during succession. It is crucial to investigate the coupling mechanism between SM and Normalized Difference Vegetation Index (NDVI), which can drive terrestrial carbon sinks while maintaining water sustainability. The Granger causality was used to analyze the unidirectional and bidirectional coupling relationship of SM and NDVI in the 0–289 cm soil layers. The windowed cross correlation was utilized to quantify the bidirectional time lag effect. The findings indicate that the vegetation improved significantly (92.47%) in 2001–2021 in the arid–semiarid area, while the SM in all four layers showed a decreasing trend (>50%). In most areas, NDVI was bidirectional dependent on SM. Vegetation dominated the loss of shallow SM (<100 cm) through root uptake and transpiration, whereas deep SM (>100 cm) in turn dominated the vegetation growth, structure and spatial pattern. At the spatial scale, the top layer of SM in the arid area demonstrated less sensitivity to NDVI due to coupling with the atmosphere. Instead, the influence of NDVI on SM in the semiarid area was dominant, so more attentiveness to the consumption of SM by vegetation is needed. The bidirectional legacy effect could be up to 6 months, attributed to water transport distance, vegetation root systems and physiological mechanisms. The correlation reversed when the lag time was extended or the soil layer was deepened, which means that the greening of vegetation will intensify deep soil drying. Differences in functional traits among plants lead to varying responses. The changes of deep SM need to focus on when implementing artificial meadow construction. This study provides a theoretical basis for optimizing ecological engineering projects, which is essential for restoring global drylands ecosystems.

Aging under endocrine hormone regulation.

Aging is a biological process in which the environment interacts with the body to cause a progressive decline in effective physiological function. Aging in the human body can lead to a dysfunction of the vital organ systems, resulting in the onset of age-related diseases, such as neurodegenerative and cardiovascular diseases, which can seriously affect an individual's quality of life. The endocrine system acts on specific targets through hormones and related major functional factors in its pathways, which play biological roles in coordinating cellular interactions, metabolism, growth, and aging. Aging is the result of a combination of many pathological, physiological, and psychological processes, among which the endocrine system can achieve a bidirectional effect on the aging process by regulating the hormone levels in the body. In this paper, we explored the mechanisms of growth hormone, thyroid hormone, and estrogen in the aging process to provide a reference for the exploration of endocrine mechanisms related to aging.

Dyslexia Antedating and Postdating Epilepsy Onset

IntroductionIn children with epilepsy, comorbidities are frequent. In dyslexia, comorbidities are increasingly acknowledged. Little is known about temporal aspects (dyslexia antedating or postdating epilepsy onset, time interval), epilepsy types, and dyslexia phenotypes.MethodFrom over 1000 files of children with epilepsy, 51 cases were retrospectively identified with a formal diagnosis of dyslexia. Ages at diagnoses of dyslexia and epilepsy, epilepsy variables, and dyslexia-related neuro-cognition (phoneme deletion and rapid letter naming) were recorded.AnalysesTemporal variables, epilepsy variables, and neuro-cognition were analyzed with chi-squared, t tests, ancova, and generalized linear models.ResultsDuration of epilepsy to diagnosis of dyslexia ranged from − 5.5 years (dyslexia antedating epilepsy) to 10.1 years. In 35% of the children, diagnosis of dyslexia antedated the emergence of epilepsy. Dyslexia was seen across seizure types, with some preference for temporal lobe and rolandic epilepsy; rates for antedating and postdating dyslexia were similar. Notably, encephalopathic development was also seen. No specific dyslexia phenotype was seen. Children with dyslexia diagnoses after or in close temporal relationship to diagnoses of epilepsy (shortly before or after) scored lower on phonology and naming.ConclusionAntedating and postdating dyslexia can be seen in all epilepsy types. In a natural setting, dyslexia may antedate or postdate the emergence of epilepsy by several years. Around the time the epilepsy is about to surface, scores on dyslexia-related neuro-cognitive tasks are lowest, suggesting a bidirectional effect of the seizure condition on cognition. Encephalopathic development may be mimicking dyslexia criteria in some cases.

Endoplasmic Reticulum Stress Mediated NLRP3 Inflammasome Activation and Pyroptosis in THP-1 Macrophages Infected with Bacillus Calmette-Guérin.

Tuberculosis (TB) is a zoonotic infectious disease caused by Mycobacterium tuberculosis (Mtb). Mtb is a typical intracellular parasite, and macrophages are its main host cells. NLRP3 inflammasome-mediated pyroptosis is a form of programmed cell death implicated in the clearance of pathogenic infections. The bidirectional regulatory effect of endoplasmic reticulum stress (ERS) plays a crucial role in determining cell survival and death. Whether ERS is involved in macrophage pyroptosis with Mtb infection remains unclear. This article aims to explore the regulation of the NLRP3 inflammasome and pyroptosis by ERS in THP-1 macrophages infected with Mycobacterium bovis Bacillus Calmette-Guérin (BCG). The results showed that BCG infection induced THP-1 macrophage ERS, NLRP3 inflammasome activation and pyroptosis, which was inhibited by ERS inhibitor TUDCA. NLRP3 inhibitor MCC950 inhibited THP-1 macrophage NLRP3 inflammasome activation and pyroptosis caused by BCG infection. Compared with specific Caspase-1 inhibitor VX-765, pan-Caspase inhibitor Z-VAD-FMK showed a more significant inhibitory effect on BCG infection-induced pyroptosis of THP-1 macrophages. Taken together, this study demonstrates that ERS mediated NLRP3 inflammasome activation and pyroptosis after BCG infection of THP-1 macrophages, and that BCG infection of THP-1 macrophages induces pyroptosis through canonical and noncanonical pathways.

Immune regulation of the gut-brain axis and lung-brain axis involved in ischemic stroke.

Local ischemia often causes a series of inflammatory reactions when both brain immune cells and the peripheral immune response are activated. In the human body, the gut and lung are regarded as the key reactional targets that are initiated by brain ischemic attacks. Mucosal microorganisms play an important role in immune regulation and metabolism and affect blood-brain barrier permeability. In addition to the relationship between peripheral organs and central areas and the intestine and lung also interact among each other. Here, we review the molecular and cellular immune mechanisms involved in the pathways of inflammation across the gut-brain axis and lung-brain axis. We found that abnormal intestinal flora, the intestinal microenvironment, lung infection, chronic diseases, and mechanical ventilation can worsen the outcome of ischemic stroke. This review also introduces the influence of the brain on the gut and lungs after stroke, highlighting the bidirectional feedback effect among the gut, lungs, and brain.

Co-pyrolysis of biomass and polyethylene: Insights into characteristics, kinetic and evolution paths of the reaction process

Investigation on the distribution and mechanism of co-pyrolysis products is vital to the directional control and high-value utilization of agriculture solid wastes. Co-pyrolysis, devolatilization, kinetics characteristics, and evolution paths of corn stalk (CS) and low-density-polyethylene (LDPE) were investigated via thermogravimetric experiments. The co-pyrolysis behaviors could be separated into two stages: firstly, the degradation of CS (150– 400 °C); secondly, the degradation of CS (400– 550 °C). The devolatilization index (DI) increased with the addition of LDPE. Furthermore, a combination of devolatilization chemical analysis with product analysis to analyze the intrinsic mechanism during co-pyrolysis. The results indicated that the yield of alkanes and olefin in gas products increased with the addition of LDPE. Additionally, LDPE pyrolysis maybe abstract hydrogen from CS pyrolysis and evolved into hydrogen, methane, and ethylene. Further, the co-pyrolysis kinetic parameters were computed by using model-free isoconversion methods, which showed promotion of CS pyrolysis and the reduced activation energy. All the activation energy were declined, which indicated a “bidirectional positive effect” during co-pyrolysis. The mean activation energy of P-cellulose (P-CE), P-hemicellulose (P-HM), P-lignin (P-LG), and LDPE decreased by 23.49 %, 12.89 %, 15.36 %, and 27.82 %, respectively. This study further proves the hydrogen donor transfer pathway in the co-pyrolysis process of CS and LDPE, providing theoretical support for the resource utilization of agricultural solid waste.

Bidirectional association between depressive symptoms and cardiovascular disease in the middle-aged and elderly Chinese: a 5-year longitudinal study

ObjectiveDepressive symptoms and cardiovascular diseases (CVDs) are important issues affecting the health of the middle-aged and elderly population in China. This study aimed to investigate the bidirectional association between depressive...

Time-varying spillover networks of green bond and related financial markets

In this paper, we investigate the interrelationship between the green bond market and other major financial markets by using the Granger causality test and spillovers network analysis based on a time-varying parameter vector autoregressive (TVP-VAR) model. Our empirical findings include: (i) there exists a significant bidirectional spillover effect between the green bond market and the U.S. Treasury market; (ii) the connectedness between green bonds and other markets has increased significantly, especially the risk spillovers from the stock markets, during periods of economic turmoil; (iii) the carbon market and the energy futures market had spillovers on the green bond market before the publication of the Green Bond Principles in 2014. We also explore the influence of COVID-19 on the spillovers network. There are strong implications of these findings for investors to manage portfolios and for policymakers to improve reregulation.

Fibroblast activating protein promotes the proliferation, migration, and activation of fibroblasts in oral submucous fibrosis.

Fibroblast activating protein (FAP) is associated with various organ fibrosis. However, the expression and molecular function of FAP in oral submucous fibrosis (OSF) is still unclear. The high-performance liquid chromatography was used to detect the presence of alkaloids in areca nut extract (ANE). Real-time qPCR, Western blot, and Immunohistochemistry assay were used to analyze the expression of FAP mRNA or protein in OSF and normal oral tissue. A chi-squared test analyzed the relationship between FAP protein expression and clinicopathological data of OSF patients. CCK-8, Wound-healing, and Transwell migration assay were employed to assess the effect of the proliferation and migration ability of hOMF cells with FAP overexpression or knockdown. The expression level of a-SMA, FSP1, and P13K-Akt signaling pathways-related protein in hOMF cells transfected with FAP overexpression or knockdown plasmid was verified by western blot assay. The four specific areca alkaloids (Arecoline, Guvacine, Arecaidine, and Guvacoline) were successfully detected in the ANE. The viability of hOMF cells was significantly improved in the 50 μg/mL ANE group and was inhibited in the 5 and 50 mg/mL ANE groups. The expression of FAP was upregulated in OSF tissues, and hOMF cells treated with 50 μg/mL ANE and was related to pathology grade, clinical stage, and history of chewing betel nut. Additionally, FAP may promote the proliferation, migration, and activation of hOMF cells through the P13K-Akt signaling pathway. This study found that ANE had a bidirectional effect on the viability of hOMF cells, and the FAP gene was a potential therapeutic target in OSF.

The Impact of Industrial Agglomeration on Supply Chain Efficiency in Manufacturing

The 20th National Congress of the Communist Party of China pointed out that China's high-quality economic development needed to improve the stability and resilience of the supply chain. And the improvement of manufacturing supply chain efficiency affected markedly on this. Firstly, this paper quantified the supply chain efficiency by using the three-stage DEA model, and established an evaluation system of digital capability from the perspective of green economy. Secondly, the bidirectional fixed effect model was used to further analyze the influence of specialized agglomeration, diversified agglomeration on supply chain efficiency and the moderating effect of digital capability. Based on the above, the conclusion was drawn specialized agglomeration and diversified agglomeration affected positively on manufacturing supply chain efficiency, and digital capability moderated them positively. Then, the result of the robustness analysis showed the model is robust. Finally, this paper put forward suggestions from the aspects of government and enterprise, advocating the development of specialized agglomeration, diversified agglomseration and digital capability.

A novel 3D bidirectional auxetic metamaterial with lantern-shape: Elasticity aspects and potential for load-bearing structure

Lantern, also known as coloured-lantern making, is known for being an ancient traditional craft in China that can be dated back as early as West Han Dynasty. Inspired by the lantern, the lattice element is built by vertically rotating and duplicating the 2D units, then the 3D auxetic metamaterial is formed by connecting the 8 ligaments of the lattice element on two perpendicular planes. As the elastic behaviors associated with this metamaterial are still almost unknown to a large extent, in this study, an analysis has been conducted to investigate how the geometric parameters related to the lattice design influence its elasticity. For this reason, a novel 3D lantern-shaped honeycomb structure (LSH) has been proposed, the Castigliano's second theorem, energy principle, and Moore's theorem are utilized to solve its Young’s modulus and Poisson’s ratio in the three main directions. The theoretical results exhibit good agreement with the numerical and experimental results. The results showed that the elasticity of LSH structures can be programmed by adjusting a range of geometric parameters. In addition, LSH features a bidirectional zero Poisson effect and a good stress distribution during compression. It shows potential in terms of load-bearing to meet the requirement of lightweight and high stiffness. This structure shows good promise for applications in aerospace, construction and other fields.

Exploring the relationship between digital trails of social signals and bitcoin returns

PurposeThis study aims to empirically investigate the linkages between digital trails of social signals (content and profile features of bitcoin-related tweets) and bitcoin price return using a VAR-BEKK-GARCH model.Design/methodology/approachBitcoin-related tweets were collected every hour for six months from September 1, 2020, to February 29, 2021. The analysis involved two steps: first, examining tweet content, profiles, sentiment and emotions; and second, investigating the relationship between social signal volatility and hourly bitcoin price return.FindingsResults indicate that bitcoin price changes can impact the sentiment expressed in tweets about bitcoin, and vice versa. While sadness exhibits a bidirectional volatility spillover with bitcoin, fear and anger display a one-period lag. Quartile analyses reveal that only fear in the second quartile shows a bidirectional spillover effect with bitcoin, while all other emotions except sadness demonstrate a unidirectional spillover effect in all remaining quartiles.Originality/valueThe study uses a novel two-step approach to analyze volatility spillovers between social signals and bitcoin price returns. Findings can guide investors and portfolio managers in making better allocation decisions and assist policymakers and regulators in reducing the adverse effects of bitcoin’s volatility on financial system stability.

Distribution of Iron, Copper, Zinc and Cadmium in Glia, Their Influence on Glial Cells and Relationship with Neurodegenerative Diseases

Recent data on the distribution and influence of copper, zinc and cadmium in glial cells are summarized. This review also examines the relationship between those metals and their role in neurodegenerative diseases like Alzheimer disease, multiple sclerosis, Parkinson disease and Amyotrophic lateral sclerosis, which have become a great challenge for today’s physicians. The studies suggest that among glial cells, iron has the highest concentration in oligodendrocytes, copper in astrocytes and zinc in the glia of hippocampus and cortex. Previous studies have shown neurotoxic effects of copper, iron and manganese, while zinc can have a bidirectional effect, i.e., neurotoxic but also neuroprotective effects depending on the dose and disease state. Recent data point to the association of metals with neurodegeneration through their role in the modulation of protein aggregation. Metals can accumulate in the brain with aging and may be associated with age-related diseases.