Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 104
Filtrar
Más filtros

País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Soft Matter ; 20(7): 1629-1650, 2024 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-38284140

RESUMEN

The multifaceted influence of combined variables on the mechanical-magnetorheological properties of isotropic and anisotropic MREs in a shear state is probed in this research. Specifically, the effects of preparation magnetic field, magnetic field intensity during rheometric testing, temperature, shear strain, angular frequency, and angle of structural matrix chains were examined. The viscoelastic properties of seven distinct MREs prepared in different pre-configuration settings were analysed by subjecting them to dynamic shear-rotational deformation at different temperatures and magnetic fields. A novel magneto-viscoelastic model was formulated for both isotropic and anisotropic MREs within the realm of linear viscoelasticity. The efficacy and robustness of this model were substantiated, offering a predictive framework for the materials' behavior. This comprehensive model explains the viscoelastic response of magnetorheological elastomers to shear loading, accounting for factors encompassing the preparation magnetic field, magnetic field intensity and temperature during testing, angular frequency, shear strain, and the orientation of the column-like matrix. Empirical findings underscored noteworthy trends, indicating that elevated temperatures led to a reduction in viscoelastic modulus, whereas increased magnetic field intensity resulted in its augmentation. Simultaneously, temperature and magnetic field intensification amplified the MR effect. Additionally, heightened preparation fields correlated with increased shear modulus, whilst variations in temperature and both magnetic fields induced noticeable changes in the Payne effect.

2.
Brain Cogn ; 175: 106136, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38301366

RESUMEN

Investigating the cognitive control processes and error detection mechanisms involved in risk-taking behaviors is essential for understanding risk propensity. This study investigated the relationship between risk propensity and cognitive control processes using an event-related potentials (ERP) approach. The study employed a Cued Go/Nogo paradigm to elicit ERP components related to cognitive control processes, including contingent negative variation (CNV), P300, error-related negativity (ERN), and error positivity (Pe). Healthy participants were categorized into high-risk and low-risk groups based on their performance in the Balloon Analogue Risk Task (BART). The results revealed risk-taking behavior influenced CNV amplitudes, indicating heightened response preparation and inhibition for the high-risk group. In contrast, the P300 component showed no group differences but revealed enhanced amplitudes in Nogo trials, particularly in high-risk group. Furthermore, despite the lack of difference in the Pe component, the high-risk group exhibited smaller ERN amplitudes compared to the low-risk group, suggesting reduced sensitivity to error detection. These findings imply that risk-taking behaviors may be associated with a hypoactive avoidance system rather than impaired response inhibition. Understanding the neural mechanisms underlying risk propensity and cognitive control processes can contribute to the development of interventions aimed at reducing risky behaviors and promoting better decision-making.


Asunto(s)
Electroencefalografía , Potenciales Evocados , Humanos , Tiempo de Reacción/fisiología , Electroencefalografía/métodos , Potenciales Evocados/fisiología , Potenciales Relacionados con Evento P300/fisiología , Cognición/fisiología
3.
Audiol Neurootol ; 29(2): 88-95, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-37607499

RESUMEN

INTRODUCTION: Mefloquine is an antimalarial medicine used to prevent and treat malaria. This medicine has some side effects, including ototoxicity. This study, which was designed in two phases, aimed to investigate the side effects of mefloquine and evaluate the preventive effects of electrical stimulation on these side effects. METHODS: In the first phase, two doses of mefloquine (50 and 200 µM) were injected into male rats, and after 7 days, they were evaluated by an auditory brainstem response (ABR) test. In the second phase, electrical stimulation was applied for 10 days, and then a toxic dose of mefloquine was injected. Similar to the first phase of the study, the animals were evaluated by an ABR test after 7 days. RESULTS: In the first phase, the results showed that a high dose of mefloquine increased the ABR threshold and wave I latency; however, these changes were not observed in the second phase. CONCLUSION: Application of electrical stimulation could prevent the ototoxic effects of mefloquine. According to the findings of the present study, electrical stimulation can be used as a preconditioner to prevent the ototoxic effects of mefloquine.


Asunto(s)
Oído Interno , Mefloquina , Masculino , Ratas , Animales , Mefloquina/efectos adversos , Estimulación Eléctrica
4.
Clin Lab ; 70(2)2024 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-38345980

RESUMEN

BACKGROUND: Bacterial persisters are non- or slow-growing phenotypic variants that may be responsible for recalcitrance and relapse of persistent infections and antibiotic failure. In Escherichia coli, mqsRA is a well-known type II toxin-antitoxin system associated with persister cell formation. This study aimed to investigate the efficiency of an antisense peptide nucleic acid (PNA) targeting mqsRA in eliminating E. coli persisters. METHODS: The study included 600 non-duplicated urine samples from adult patients with suspected urinary tract infections. The isolates were subjected to antimicrobial susceptibility testing and bacterial persister cells assay. The presence of mqsRA in the isolates was evaluated by polymerase chain reaction. Finally, expression of the mqsR and mqsA genes was assessed after exposure to normal conditions, stress, and different concentrations of mqsR-PNA (1 - 35 µM). RESULTS: The mqsR gene was significantly overexpressed under stress conditions, which was compensated by the PNA treatment. Complete inhibition of E. coli persister cells was achieved after overnight treatment with the anti-mqsR-PNA at concentrations ≥ 15 µM. CONCLUSIONS: The growth of E. coli persister cells can be inhibited by the anti-mqsR-PNA. Further studies are required to evaluate the effectiveness of this antisense PNA in both preclinical and clinical settings.


Asunto(s)
Proteínas de Escherichia coli , Ácidos Nucleicos de Péptidos , Humanos , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Ácidos Nucleicos de Péptidos/genética , Ácidos Nucleicos de Péptidos/farmacología , Ácidos Nucleicos de Péptidos/metabolismo , Bacterias , Antibacterianos/farmacología
5.
Cogn Emot ; 38(5): 661-674, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39137915

RESUMEN

The traditional view of cognition as detached from emotions is recently being questioned. This study aimed to investigate the influence of emotional valence on the accuracy and bias in the representation of numbers on the mental number line (MNL). The study included 164 participants who were randomly assigned into two groups with induced positive and negative emotional valence using matched arousal film clips. Participants performed a computerised number-to-position (CNP) task to estimate the position of numbers on a horizontal line. The results showed that participants in the positive valence group exhibited a rightward bias, while those in the negative valence group showed an opposite pattern. The analysis of mean absolute error revealed that the negative valence group had higher error rates compared to the positive valence group. Furthermore, the MNL estimation pattern analysis indicated that a two-cycle cyclic power model (CPM) best explained the data for both groups. These findings suggest that emotional valence influences the spatial representation of numbers on the MNL and affects accuracy in numerical estimations. Our findings are finally discussed in terms of body-specificity and the Brain's Asymmetric Frequency Tuning (BAFT) theories. The study provides new insights into the interplay between emotions and numerical cognition.


Asunto(s)
Emociones , Humanos , Femenino , Masculino , Adulto Joven , Adulto , Cognición , Conceptos Matemáticos , Percepción Espacial
6.
Environ Manage ; 73(1): 34-50, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37658901

RESUMEN

This study applies the mental model and cognitive mapping method to involve stakeholders in delineating the mutual relations between sources of water, energy, and food (WEF) production in the Varamin Plain (VP). Through involving farmers and managerial experts, the approach facilitates the deployment of community communication patterns to recognize and comprehend problems and move from single-loop learning to double-loop learning. The dynamic model was driven from the final mental model of the participants to reflect changes in the systems over time. The system dynamic (SD) model incorporates three scenarios for enhancing irrigation efficiency, managing groundwater extraction, and satisfying environmental needs. The results uncovered that the surface and underground water resources of the VP will gradually decrease within the next two decades in the range of 158 and 2700 million cubic meters (MCM) per year. Also, the plain suffers from water insecurity and a 162 MCM shortage. Consequently, focusing on understanding the nexus and nexus governance can enhance resource management and achieve sustainable development goals. Essentially, promoting collaborative governance, such as creating cooperative organizations and implementing double-loop learning, and instituting a water market, regulatory governance, and monitoring laws can improve the state of Varamin Plain's resources. These results carry important policy implications for using mental models to consider dynamics for discussions on participatory management of the WEF system nexus and environmental management.


Asunto(s)
Abastecimiento de Agua , Agua , Humanos , Irán , Abastecimiento de Alimentos , Modelos Psicológicos
7.
Water Sci Technol ; 89(8): 2044-2059, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38678408

RESUMEN

Desalination processes are energy consuming and it is required to apply clean energy sources for supplying them to prevent environmental issues. Solar energy is one of the attractive clean energy sources for desalination. In solar thermal desalination systems, different thermal components could be used for heat transfer purpose. In solar desalination technologies, heat pipe as efficient heat transfer mediums could be employed to transfer absorbed and/or stored thermal energy. The objective of this study is to review applications of heat pipes in solar energy desalination systems. Regarding the performance dependency of these thermal systems on the variety of factors, scholars have investigated these systems by consideration of the effect of different influential factors. Based on the results, it is concluded that use of heat pipes could lead to proper performance of solar desalination systems. Aside from direct transfer of absorbed heat from solar radiation, heat pipes can be applied in the storage units of solar desalination systems to keep the systems active in night-hours or low solar irradiation conditions. The overall performance of the solar desalinations systems with heat pipes can be influenced by some factors such as filling ratio and operating fluid that affect the performance of heat pipes.


Asunto(s)
Calor , Energía Solar , Purificación del Agua/métodos , Luz Solar
8.
Biomed Eng Online ; 22(1): 79, 2023 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-37573331

RESUMEN

In order to study the local interactions between facial soft-tissues and a Silhouette Soft® suspension suture, a CE marked medical device designed for the repositioning of soft tissues in the face and the neck, Finite element simulations were run, in which a model of the suture was embedded in a three-layer Finite Element structure that accounts for the local mechanical organization of human facial soft tissues. A 2D axisymmetric model of the local interactions was designed in ANSYS, in which the geometry of the tissue, the boundary conditions and the applied loadings were considered to locally mimic those of human face soft tissue constrained by the suture in facial tissue repositioning. The Silhouette Soft suture is composed of a knotted thread and sliding cones that are anchored in the tissue. Hence, simulating these interactions requires special attention for an accurate modelling of contact mechanics. As tissue is modelled as a hyper-elastic material, the displacement of the facial soft tissue changes in a nonlinear way with the intensity of stress induced by the suture and the number of the cones. Our simulations show that for a 4-cone suture a displacement of 4.35 mm for a 2.0 N external loading and of 7.6 mm for 4.0 N. Increasing the number of cones led to the decrease in the equivalent local strain (around 20%) and stress (around 60%) applied to the tissue. The simulated displacements are in general agreement with experimental observations.


Asunto(s)
Suturas , Humanos , Análisis de Elementos Finitos , Cadáver , Fenómenos Biomecánicos , Estrés Mecánico
9.
Can J Microbiol ; 69(3): 123-135, 2023 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-36495587

RESUMEN

Integrative and conjugative elements (ICEs) are self-transferable mobile genetic elements that play a significant role in disseminating antimicrobial resistance between bacteria via horizontal gene transfer. A recently identified ICE in a clinical isolate of Histophilus somni (ICEHs02) is 72 914 base pairs in length and harbours seven predicted antimicrobial resistance genes conferring resistance to tetracycline (tetR-tet(H)), florfenicol (floR), sulfonamide (Sul2), aminoglycosides (APH(3″)-Ib, APH(6)-Id, APH(3')-Ia), and copper (mco). This study investigated ICEHs02 host range, assessed effects of antimicrobial stressors on transfer frequency, and examined effects of ICEHs02 acquisition on hosts. Conjugation assays examined transfer frequency of ICEHs02 to H. somni and Pasteurella multocida strains. Polymerase chain reaction assays confirmed the presence of a circular intermediate, ICE-associated core genes, and cargo genes in recipient strains. Susceptibility testing examined ICEHs02-associated resistance phenotypes in recipient strains. Tetracycline and ciprofloxacin induction significantly increased the transfer rates of ICEHs02 in vitro. The copy numbers of the circular intermediate of ICEHs02 per chromosome exhibited significant increases of ∼37-fold after tetracycline exposure and ∼4-fold after ciprofloxacin treatment. The acquisition of ICEHs02 reduced the relative fitness of H. somni transconjugants (TG) by 28% (w = 0.72 ± 0.04) and the relative fitness of P. multocida TG was decreased by 15% (w = 0.85 ± 0.01).


Asunto(s)
Transferencia de Gen Horizontal , Pasteurellaceae , Farmacorresistencia Bacteriana Múltiple/genética , Antibacterianos/farmacología , Ciprofloxacina , Tetraciclinas , Conjugación Genética
10.
Psychol Res ; 87(6): 1836-1847, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-36607427

RESUMEN

Emotions influence our perception of time. Arousal and valence are considered different dimensions of emotions that might interactively affect the perception of time. In the present study, we aimed to investigate the possible time distortions induced by emotional (happy/angry) high-arousing faces compared to neutral, low-arousing faces. Previous works suggested that emotional stimuli enhance the amplitudes of several posterior components, such as Early Posterior Negativity (EPN) and Late Positive Potential (LPP). These components reflect several stages of emotional processing. To this end, we conducted an event-related potential (ERP) study with a temporal bisection task. We hypothesized that the partial dissociation of these ERP components would shed more light on the possible relations of valence and arousal on emotional facial regulation and their consequential effects on behavioral timing. The behavioral results demonstrated a significant effect for emotional stimuli, as happy faces were overestimated relative to angry faces. Our results also indicated higher temporal sensitivity for angry faces. The analyzed components (EPN and LLP) provided further insights into the qualitative differences between stimuli. Finally, the results were interpreted considering the internal clock model and two-stage processing of emotional stimuli.


Asunto(s)
Electroencefalografía , Emociones , Humanos , Emociones/fisiología , Potenciales Evocados/fisiología , Ira , Felicidad , Expresión Facial
11.
Drug Chem Toxicol ; : 1-10, 2023 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-38058159

RESUMEN

Aflatoxins, a group of toxic secondary metabolites produced by Aspergillus species, pose significant threats to human health due to their potent carcinogenic, mutagenic, and immunosuppressive properties. Chronic exposure to these contaminants, commonly found in staple foods such as maize and groundnuts, has been linked to an increased risk of liver cancer, growth impairment, and immune dysfunction. Several agents, such as calcium montmorillonite clay and Lactobacillus rhamnosus GG, have shown promise in reducing aflatoxin bioavailability and alleviating its toxic effects. Additionally, dietary supplements such as chlorophyllin, selenium, and N-acetylcysteine have demonstrated potential as adjuvants to counteract aflatoxin-induced oxidative stress and support liver function. In this treatise, some of the most discussed approaches to mitigating aflatoxin effects are explored in terms of their efficacy, safety, and potential mechanisms of action, which include direct aflatoxin binding, detoxification, cellular antioxidative, and hepatocellular protection properties. However, the effectiveness of these strategies can be influenced by various factors, such as dose, duration of exposure, and individual susceptibility. Therefore, further research is needed to optimize these interventions and develop new, targeted therapies for the prevention and treatment of aflatoxin-related diseases. This review aims to provide a comprehensive analysis of 18 pharmaceutical, nutraceutical, supplement, and probiotic strategies currently available for mitigating the deleterious effects of chronic aflatoxin exposure in humans and animal models.

12.
Exp Brain Res ; 240(7-8): 2027-2038, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35576072

RESUMEN

The timing ability plays an important role in everyday activities and is influenced by several factors such as the attention and arousal levels of the individuals. The effects of these factors on time perception have been interpreted through psychological models of time, including Attentional Gate Model (AGM). On the other hand, research has indicated that neurofeedback (NFB) training improves attention and increases arousal levels in the clinical and healthy population. Regarding the link between attentional processing and arousal levels and NFB and their relation to time perception, this study is a pilot demonstration of the influence of SMR-Beta1 (12-18 Hz) NFB training on time production and reproduction performance in healthy adults. To this end, 12 (9 female and 3 males; M = 26.3, SD = 3.8) and 12 participants (7 female and 5 males; M = 26.9, SD = 3.1) were randomly assigned into the experimental (with SMR-Beta1 NFB) and control groups (without any NFB training), respectively. The experimental group underwent intensive 10 sessions (3 days a week) of the 12-18 Hz up-training. Time production and reproduction performance were assessed pre and post NFB training for all participants. Three-way mixed ANOVA was carried out on T-corrected scores of reproduction and production tasks. Correlation analysis was also performed between SMR-Beta1 and time perception. While NFB training significantly influenced time production (P < 0.01), no such effect was observed for the time reproduction task. The results of the study are finally discussed within the frameworks of AGM, dual-process and cognitive aspects of time perception. Overall, our results contribute to disentangling the underlying mechanisms of temporal performance in healthy individuals.


Asunto(s)
Neurorretroalimentación , Percepción del Tiempo , Adulto , Atención , Encéfalo , Electroencefalografía/métodos , Femenino , Humanos , Masculino
13.
Exp Brain Res ; 240(9): 2311-2326, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35876852

RESUMEN

The evidence for the hemispheric specialization of motor planning reveals several inconsistencies between the left-lateralized hypothesis and a distributed system across the hemispheres. We compared participants with left hemiplegic cerebral palsy (HCP) to right-handed control subjects in this study's first experiment by inviting them to perform a motor planning task. Participants were required to release the start button, grasp a hexagon, and rotate it according to the instructions. In the second experiment, we compared left-HCP subjects with right-HCP subjects inviting them to perform the same task (we used the data for left-HCP subjects from the first experiment). P2 amplitude, as well as planning time, grasping time, releasing time, and initial grip selection planning patterns, were used as outcome measures in both experiments. The first experiment revealed that controls acted more quickly and chose more effective planning patterns. Also, the P2 amplitude was smaller in left-HCP subjects than in control subjects. No significant group effect was observed in the second experiment for any movement-related measure or P2. At the neural level, however, there was an interaction between 'region' and 'group,' indicating the distinction between the two groups in the right region. The results are discussed in terms of motor planning's hemispheric distribution and individual differences in the HCP group.


Asunto(s)
Parálisis Cerebral , Parálisis Cerebral/complicaciones , Potenciales Evocados , Lateralidad Funcional , Fuerza de la Mano , Hemiplejía/etiología , Humanos , Desempeño Psicomotor
14.
Neurocase ; 28(2): 218-225, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35533270

RESUMEN

The purpose of this single subject study was to investigate whether transcranial direct current stimulation (tDCS) applied to both hemispheres combined with speech therapy can improve language learning in a pair of 5-year-old twins with corpus callosum dysgenesis (CCD). The treatment protocol included anodal tDCS with simultaneous speech therapy in one of the participants (T.D.), and sham-tDCS with the same montage, and stimulation regime concomitant with speech therapy for the other twin (A.D.). Our findings show that T.D. improved in language production when treated with speech therapy in combination with tDCS. A.D. showed evidence for a relatively minor behavioral benefit from speech therapy.


Asunto(s)
Estimulación Transcraneal de Corriente Directa , Agenesia del Cuerpo Calloso , Preescolar , Humanos , Lenguaje , Logopedia , Estimulación Transcraneal de Corriente Directa/métodos , Gemelos Monocigóticos
15.
J Craniofac Surg ; 33(7): 2095-2099, 2022 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-35275873

RESUMEN

OBJECTIVE: Nasoalveolar molding (NAM) is a technique that is utilized in patients with cleft lip/palate before performing lip surgery. This procedure has been shown to result in a more aesthetic nose with lesser columellar deviation and reduced scaring. The aim of our study was to evaluate the long-term results of NAM and gingivoperiosteoplasty in patients with cleft lip and palate. METHODS AND MATERIALS: An electronic search of databases (ie, PubMed, ISI Web of Science, EMBASE, Scopus, and Google Scholar) from inception to March 2021 was performed and after selecting the eligible studies, relevant data were collected using piloted extraction forms. The success rate of NAM and gingivoperiosteoplasty, and Bergland score were pooled using random-effects inverse variance meta-analysis. RESULTS: Seven studies were included in this meta-analysis and systematic review. The pooled mean success rate of NAM with gingivoperiosteoplasty (GPP) based on the continuity of alveolar bone structure was 71% (95% confidence interval [CI] = 54-85). This means that in 71% of cases NAM + GPP treatment eliminated the need for future bone grafts. Also, no significant difference between the success rate (risk ratio = 1.00, 95% CI = 0.64-1.58) and mean Bergland score (mean difference = 0.64, 95% CI = -1.04 to 2.31) of NAM + GPP and skeletal bone graft was found. CONCLUSIONS: Nasoalveolar molding and gingivoperiosteoplasty was successful in 71% of cases treating patients with cleft lip and palate. This treatment is similar with the secondary alveolar bone graft in both the success rate and the alveolar height that it generates while being less invasive and with lower morbidity.


Asunto(s)
Labio Leporino , Fisura del Paladar , Proceso Alveolar/cirugía , Trasplante Óseo , Labio Leporino/cirugía , Fisura del Paladar/cirugía , Estética Dental , Humanos , Lactante , Modelado Nasoalveolar , Nariz/cirugía , Estudios Retrospectivos
16.
Psychol Res ; 85(5): 2023-2035, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32623512

RESUMEN

A growing body of research suggests that space, time and number are represented within a common system. Other studies have shown this relationship is related to the mathematical competency. Here we examined the influence of the mathematical capacities of 8-12 years old children, grouped into high (n = 63) and low (n = 58) on performance in mental number line, time knowledge and time perception. The results revealed that mathematical competency influences mental number line and time knowledge, but with regard to time perception the effects were only observed in time production task. In addition, the results of correlation analysis revealed interaction between time knowledge, time production (but not reproduction) and mental number line. Finally, the findings are discussed within the framework of the recent theories regarding representation of space, time and number.


Asunto(s)
Desarrollo Infantil , Cognición , Matemática/educación , Percepción del Tiempo , Éxito Académico , Niño , Humanos , Competencia Mental , Procesos Mentales , Psicología Educacional , Análisis y Desempeño de Tareas
17.
J Therm Biol ; 100: 103073, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34503810

RESUMEN

Hyperthermia technique has received much attention over the last decade being less invasive among the others. Laser therapy is among the most commonly investigated types of ablative hyperthermia for treatment of cancer. In this method an external heat source provided by a laser fiber leads the cancerous tissue to the necrosis stage. For its simulation a cylindrical geometry of a breast tissue containing a tumor is acted upon by a Gaussian form of laser radiation. Then the feasibility of a fat layer injection around the tumor during the therapy is investigated numerically. In order to consider the finite speed of heat transfer, dual phase lag (DPL) model is implemented for prediction of the thermal results. The therapy is addressed with and without the presence of a fat layer around the breast tumor. Results show that the temperature in the tumor increases up to 15 % by the injection of a fat layer. Also, the presence of a fat layer around the tumor shows that the irreversible ablation happens at a faster rate.


Asunto(s)
Neoplasias de la Mama/terapia , Convección , Terapia por Láser/métodos , Modelos Teóricos , Tejido Adiposo/efectos de la radiación , Femenino , Análisis de Elementos Finitos , Humanos , Glándulas Mamarias Humanas/efectos de la radiación
18.
Fetal Pediatr Pathol ; 40(5): 442-454, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31984822

RESUMEN

BACKGROUND: Cleidocranial dysplasia (CCD) is a genetic disorder with an autosomal dominant inheritance pattern. CCD characterized by abnormal clavicles, patent sutures and fontenelles, supernumerary teeth and short stature. Approximately 60-70% of CCD patients have mutations in the RUNX2 gene. The RUNX2 gene is an essential transcription factor for chondrocyte maturation, osteoblast differentiation and bone formation. Runx2 regulates mesenchymal cell proliferation in sutures and suture closure by inducing the signaling pathways of the genes of Fgf, Pthlh, hedgehog and Wnt. Material and Methods: We summarized molecular genetics aspects of CCD. Result: Approximately 94% of CCD patients have dental anomalies, the most common of which are supernumerary tooth. Dental anomalies are not determined solely by gene mutations of RUNX2, but are also affected by modifier genes, environmental factors, epigenetic factors and copy number variations. Conclusion: a definite diagnosis of CCD should include the patient's clinical history, symptoms and signs, as well as genetic analyses.


Asunto(s)
Displasia Cleidocraneal , Subunidad alfa 1 del Factor de Unión al Sitio Principal/genética , Displasia Cleidocraneal/genética , Variaciones en el Número de Copia de ADN , Humanos , Mutación , Factores de Transcripción/genética
19.
Med J Islam Repub Iran ; 35: 39, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34211941

RESUMEN

Background: There is conflicting evidence in favor of the hemispheric distribution of motor planning. Some studies supported the left-hemisphere-dominance hypothesis for motor planning and claimed that the left-hemisphere has a crucial function in motor control even in left-handers. The present study aimed to compare the right- and left-handed participants on motor planning ability and to investigate the performance of their dominant hands in a specific action selection task. Also, the effect of task complexity was assessed. Methods: Twenty right-handers and 20 left-handers performed an action selection task. The participants had to grasp a hexagonal knob with their dominant hand and consequently rotated it 60° or 180 ° clockwise or counterclockwise. Depending on our objects, we used mixed factorial ANOVA and the groups were examined in terms of the planning time, grasping time, releasing time and planning pattern for initial grip selection. The SPSS 19 was used for analyzing the data and p≤0.05 was considered as the significant level. Results: No significant differences were observed between the two groups. The movement-related measures revealed a main effect of rotation (p˂0.001). However, a significant interaction between direction × planning pattern × group (p˂0.001) indicated a preferential bias for rotatory movements in the medial direction which is consistent with the "medial over lateral advantage". Conclusion: Both left- and right-handed participants had a similar motor planning ability while performing a planning task with their dominant hands. Because our study was behavioral, it only provided a test of the left-hemisphere hypothesis of motor planning.

20.
Cogn Process ; 21(3): 449-459, 2020 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-32212029

RESUMEN

Space, time, and number are among fundamental aspects of behavior and reasoning about the environment. Recent studies have shown that these dimensions highly interact with each other. To explain such interaction, two theories have been proposed: A Theory of Magnitude (ATOM), which posits the existence of a common magnitude system, and Conceptual Metaphor Theory (CMT), which proposes abstract domains such as time and number are mapped through more concrete domains such as space. The present study investigates the interaction of number, time and space in a single experimental paradigm using a temporal reproduction task with a visuospatial component. We also investigated whether mathematical education and continuous involvement with calculations and numbers change the processing precision related to number, time, and space. Two groups of students in mathematics (n = 28) and Persian literature (n = 28) participated in a time reproduction task. The stimuli included Arabic numbers 1, 2, 8, and 9, which were presented to the participants over short (300, 400, 500 ms) and long durations (1000, 1100, 1200 ms) on both sides (left and right) of the monitor. The interaction effect of spatialـnumerical and temporal-numerical was found to be significant. There was no overall time-space interaction, but the triple interaction effect between number, time, and space was significant suggesting the existence of a common representational system. This main result was slightly in line with recent proposed theories. Furthermore, the results showed that the main effect of group was not significant. In addition, we found that among the three factors (number, time, and space) the effect of number is more prominent, i.e., when number disappeared the interaction effect was not observed. The results also suggest that the nature of interactions between these factors is not influenced by cognitive and educational factors. The findings of the study are finally discussed in terms of symmetrical or asymmetrical cross-dimensional influences within the frameworks of ATOM and CMT theories.


Asunto(s)
Metáfora , Percepción Espacial , Humanos , Matemática , Tiempo de Reacción , Factores de Tiempo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA