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1.
Phytother Res ; 37(7): 2800-2810, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-36808781

RESUMO

This trial was designed to evaluate the effect of a standardized capsule of Aloe vera gel (AVG) on the quality of life (QOL) in patients with systolic heart failure (HF). Forty-two patients were randomly divided into two groups to receive either AVG 150 mg or harmonized placebo capsules twice a day for 8 weeks. The patients were evaluated before and after the intervention using the Minnesota Living with Heart Failure Questionnaire (MLHFQ), New York Heart Association (NYHA) functional class, six-minute walk test (6MWT), Insomnia Severity Index (ISI), Pittsburgh Sleep Quality Index (PSQI) and STOP-BANG questionnaires. Post-intervention, AVG group indicated a significant reduction in the total score of MLHFQ (p < 0.001). The changes in MLHFQ and NYHA class were statistically significant after taking medication (p < 0.001 and p = 0.004, respectively). The change of 6MWT in the AVG group was more advanced; however, it was not statistically significant (p = 0.353). Moreover, in the AVG group, the severity of insomnia and obstructive sleep apnea decreased (p < 0.001, p = 0.01 respectively) and the sleep quality improved as well (p < 0.001). There were significantly fewer adverse events reported in the AVG group (p = 0.047). Therefore, AVG combined with standard medical therapy could provide more clinical benefits for patients with systolic HF.


Assuntos
Aloe , Insuficiência Cardíaca Sistólica , Distúrbios do Início e da Manutenção do Sono , Humanos , Qualidade de Vida , Insuficiência Cardíaca Sistólica/tratamento farmacológico , Distúrbios do Início e da Manutenção do Sono/tratamento farmacológico , Preparações de Plantas , Método Duplo-Cego , Resultado do Tratamento
2.
Neuroimage ; 256: 119179, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35429626

RESUMO

Pesticide exposure has been associated with adverse cognitive and neurological effects. However, neuroimaging studies aimed at examining the impacts of pesticide exposure on brain networks underlying abnormal neurodevelopment in children remain limited. It has been demonstrated that pesticide exposure in children is associated with disrupted brain anatomy in regions that make up the default mode network (DMN), a subnetwork engaged across a diverse set of cognitive processes, particularly higher-order cognitive tasks. This study tested the hypothesis that functional brain network connectivity/topology in Latinx children from rural farmworker families (FW children) would differ from urban Latinx children from non-farmworker families (NFW children). We also tested the hypothesis that probable historic childhood exposure to pesticides among FW children would be associated with network connectivity/topology in a manner that parallels differences between FW and NFW children. We used brain networks from functional magnetic resonance imaging (fMRI) data from 78 children and a mixed-effects regression framework to test our hypotheses. We found that network topology was differently associated with the connection probability between FW and NFW children in the DMN. Our results also indicated that, among 48 FW children, historic reports of exposure to pesticides from prenatal to 96 months old were significantly associated with DMN topology, as hypothesized. Although the cause of the differences in brain networks between FW and NFW children cannot be determined using a cross-sectional study design, the observed associations between network connectivity/topology and historic exposure reports in FW children provide compelling evidence for a contribution of pesticide exposure on altering the DMN network organization in this vulnerable population. Although longitudinal follow-up of the children is necessary to further elucidate the cause and reveal the ultimate neurological implications, these findings raise serious concerns about the potential adverse health consequences from developmental neurotoxicity associated with pesticide exposure in this vulnerable population.


Assuntos
Fazendeiros , Praguicidas , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico , Criança , Estudos Transversais , Rede de Modo Padrão , Humanos , Imageamento por Ressonância Magnética , Praguicidas/efeitos adversos
3.
Expert Syst Appl ; 205: 117703, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36035542

RESUMO

Many studies propose methods for finding the best location for new stores and facilities, but few studies address the store closing problem. As a result of the recent COVID-19 pandemic, many companies have been facing financial issues. In this situation, one of the most common solutions to prevent loss is to downsize by closing one or more chain stores. Such decisions are usually made based on single-store performance; therefore, the under-performing stores are subject to closures. This study first proposes a multiplicative variation of the well-known Huff gravity model and introduces a new attractiveness factor to the model. Then a forward-backward approach is used to train the model and predict customer response and revenue loss after the hypothetical closure of a particular store from a chain. In this research the department stores in New York City are studied using large-scale spatial, mobility, and spending datasets. The case study results suggest that the stores recommended being closed under the proposed model may not always match the single store performance, and emphasizes the fact that the performance of a chain is a result of interaction among the stores rather than a simple sum of their performance considered as isolated and independent units. The proposed approach provides managers and decision-makers with new insights into store closing decisions and will likely reduce revenue loss due to store closures.

4.
Phytother Res ; 35(11): 6101-6113, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34355443

RESUMO

Cardiovascular diseases (CVDs) comprise the most prevalent causes of morbidity and mortality in both men and women worldwide. CVDs are associated with several risk factors such as hyperlipidemia, diabetes mellitus, hypertension, obesity, tobacco smoking and an unhealthy diet. Currently, in addition to the use of related pharmacological treatments in the management of CVDs, the investigation of other suitable healthcare approaches for these disorders such as the identification of herbal medicines has been considered in the scientific communities. Aloe vera (L.) Burm.f. is a perennial medicinal plant. The innermost leaf layer of this plant contains transparent gel, which is used as food. Pre-clinical studies have shown several biological activities of A. vera gel (AVG), including antidiabetic, lipid-lowering, antioxidant, antiinflammatory, hepatoprotective, and immunomodulatory effects. Other pharmacological activities of AVG such as anti-fibrotic, anti-hypertensive, and anti-atherosclerotic effects have been reported. Moreover, several clinical studies have demonstrated the ameliorating effects of AVG on some markers of CVDs risk factors. Thus, this study was conducted to review clinical trials besides in vitro and in vivo studies on the cardiac beneficial effects of AVG. However, further high-quality studies are needed to firmly establish the clinical efficacy of the plant.


Assuntos
Aloe , Doenças Cardiovasculares , Doenças Cardiovasculares/tratamento farmacológico , Doenças Cardiovasculares/prevenção & controle , Humanos , Hipoglicemiantes , Extratos Vegetais/farmacologia , Preparações de Plantas
5.
Neurol Sci ; 41(1): 229-232, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31392638

RESUMO

OBJECTIVE: Epilepsy is a common neurological disorder, the history of which dates back to thousands of years ago. Avicenna (980-1037 AD) is a famous Persian scholar who considered different types of epilepsy and their specific treatments. His book Al-Qanun fi al-Tibb was taught in Europe for several years. Along with explaining the diseases occurring in various body organs, the book describes neurological and neuropsychological conditions such as epilepsy METHODS: This article is a review of the book Al-Qanun fi al-Tibb and some of the traditional Persian medicine sources, including Kamil al-Sinaa al Tibbiya and Makhzan-O-L Advieh, on uterine epilepsy, its etiology, clinical manifestations and treatments. Also, articles related to this topic in the field of traditional Persian medicine or historical articles have been searched for in Google Scholar search engine or PubMed database. RESULTS: Avicenna categorizes the causes of epilepsy into two main groups: those caused by brain diseases and those associated with the diseases of other organs. He believed that the stomach, the spleen, the maraqq, the uterus, or other body organs influence the brain and can cause epilepsy. In uterine epilepsy, the primary pathology lies with the uterus and can affect the brain. This condition occurs due to the retention of the menses or semen. CONCLUSION: In this historical article, we intend to explain Avicenna's viewpoint on uterine epilepsy. We suggest further studies on this topic, for example, to evaluate the frequency of epilepsy in patients with the retention of the menses or the semen.


Assuntos
Epilepsia/história , Medicina Tradicional/história , Útero , Feminino , História Medieval , Humanos , Pérsia
6.
Phytother Res ; 34(10): 2429-2430, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32472655

RESUMO

A group of patients with pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were reported from China in December 2019. Although several antiviral drugs are widely tested, none of them has been approved as specific antiviral therapy for coronavirus disease 2019 (COVID-19). Accumulating evidence established a hyperinflammatory states or cytokine storm in COVID-19. Among these cytokines, IL-6 plays a key role in cytokine storm and can predict the adverse clinical outcomes and fatality in these patients. Based on the evidence of the significant role of IL-6 in cytokine storm, diabetes mellitus, and cardiovascular diseases as principal comorbidities, it seems that anti-cytokine therapy may be useful in patients with severe COVID-19 to reduce mortality. Recent studies demonstrated that herbal-derived natural products had immunosuppressive and anti-inflammatory properties and exhibited exceptional act on mediators of inflammation. Parthenolide is the principal sesquiterpene lactones and the main biologically active constituent Tanacetum parthenium (commonly known as feverfew) which has could significantly reduce IL-1, IL-2, IL-6, IL-8, and TNF-α production pathways established in several human cell line models in vitro and in vivo studies. Therefore, parthenolide may be one of the herbal candidates for clinical evaluation.


Assuntos
Anti-Inflamatórios/farmacologia , Infecções por Coronavirus/complicações , Citocinas/metabolismo , Inflamação , Extratos Vegetais/farmacologia , Pneumonia Viral/complicações , Sesquiterpenos/farmacologia , Tanacetum parthenium/química , Anti-Inflamatórios/uso terapêutico , Betacoronavirus , COVID-19 , Coronavirus/metabolismo , Infecções por Coronavirus/tratamento farmacológico , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , Humanos , Inflamação/tratamento farmacológico , Inflamação/etiologia , Inflamação/metabolismo , Pandemias , Fitoterapia , Extratos Vegetais/uso terapêutico , Pneumonia Viral/tratamento farmacológico , Pneumonia Viral/epidemiologia , Pneumonia Viral/virologia , SARS-CoV-2 , Sesquiterpenos/uso terapêutico
7.
Hum Brain Mapp ; 40(17): 5123-5141, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31441167

RESUMO

Analyzing the structure and function of the brain from a network perspective has increased considerably over the past two decades, with regional subnetwork analyses becoming prominent in the recent literature. However, despite the fact that the brain, as a complex system of interacting subsystems (i.e., subnetworks), cannot be fully understood by analyzing its constituent parts as independent elements, most studies extract subnetworks from the whole and treat them as independent networks. This approach entails neglecting their interactions with other brain regions and precludes identifying potential compensatory mechanisms outside the analyzed subnetwork. In this study, using simulated and empirical data, we show that the analysis of brain subnetworks within the context of their whole-brain networks, that is, including their interactions with other brain regions, can yield different outcomes when compared to analyzing them as independent networks. We also provide a multivariate mixed-effects modeling framework that allows analyzing subnetworks within the context of their whole-brain networks, and show that it can better disentangle global (whole-brain) and local (subnetwork) differences when compared to standard t-test analyses. T-test analyses may produce misleading results in identifying complex global and local level differences. The provided multivariate model is an extension of a previously developed model for global, system-level hypotheses about the brain. The modified version detailed here provides the same utilities as the original model-quantifying the relationship between phenotypes and brain connectivity, comparing brain networks among groups, predicting brain connectivity from phenotypes, and simulating brain networks-but for local, subnetwork-level hypotheses.


Assuntos
Encéfalo/diagnóstico por imagem , Conectoma , Modelos Neurológicos , Rede Nervosa/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Neuroimagem
8.
Hum Brain Mapp ; 40(1): 175-186, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30256496

RESUMO

Complex brain networks formed via structural and functional interactions among brain regions are believed to underlie information processing and cognitive function. A growing number of studies indicate that altered brain network topology is associated with physiological, behavioral, and cognitive abnormalities. Graph theory is showing promise as a method for evaluating and explaining brain networks. However, multivariate frameworks that provide statistical inferences about how such networks relate to covariates of interest, such as disease phenotypes, in different study populations are yet to be developed. We have developed a freely available MATLAB toolbox with a graphical user interface that bridges this important gap between brain network analyses and statistical inference. The modeling framework implemented in this toolbox utilizes a mixed-effects multivariate regression framework that allows assessing brain network differences between study populations as well as assessing the effects of covariates of interest such as age, disease phenotype, and risk factors on the density and strength of brain connections in global (i.e., whole-brain) and local (i.e., subnetworks) brain networks. Confounding variables, such as sex, are controlled for through the implemented framework. A variety of neuroimaging data such as fMRI, EEG, and DTI can be analyzed with this toolbox, which makes it useful for a wide range of studies examining the structure and function of brain networks. The toolbox uses SAS, R, or Python (depending on software availability) to perform the statistical modeling. We also provide a clustering-based data reduction method that helps with model convergence and substantially reduces modeling time for large data sets.


Assuntos
Encéfalo/diagnóstico por imagem , Interpretação Estatística de Dados , Processamento de Imagem Assistida por Computador/métodos , Modelos Teóricos , Rede Nervosa/diagnóstico por imagem , Neuroimagem/métodos , Software , Humanos , Análise Multivariada
9.
Neurol Sci ; 39(6): 1121-1124, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29633058

RESUMO

There are studies that show that the concepts of epilepsy have been rooted in Persian medicine; Avicenna "Ibn-e-Sina"-one of the great Persian physicians in the Islamic golden age (9th-12th century AD)-has considered some types of epilepsy with the association of the stomach, the spleen, the "Maraqq," and the whole body which has not been reviewed properly. These organs influence on the brain and can cause epilepsy. This article presents concept of Maraqq-related epilepsy; according to Avicenna's view, "Maraqq" is a membranous structure which is located in the abdomen (equivalent of parietal peritoneum in current nomenclature). We discuss his viewpoint about the diagnosis and treatment of Maraqq-related epilepsy with focus on herbal remedies. The concept of a relationship between the "Maraqq" and the brain is well discussed in the old Persian medicine texts; however, it seems that further studies in this area are required to clarify Avicenna's view about the pathophysiological mechanisms, clinical manifestations, and treatment strategies.


Assuntos
Epilepsia/história , Medicina Arábica/história , Peritônio , Médicos/história , Epilepsia/diagnóstico , Epilepsia/fisiopatologia , Epilepsia/terapia , História Medieval , Humanos , Peritônio/fisiopatologia
11.
Neurol Sci ; 38(1): 193-196, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27770272

RESUMO

One of the best remaining manuscripts is the "Canon of Medicine" fathered by Avicenna in the Islamic Golden Age [ninth to twelfth century AD]. Considering Avicenna's role in the development of medical science in the Islamic Golden Age, we reviewed Avicenna's point of view on sexual headache based on his famous book "Canon of Medicine". This historical review discusses the clinical approaches applied to diagnose, classify, and treat sexual headache-specifically herbal therapy-from the viewpoint of Avicenna and Traditional Persian Medicine. The accurate observations of Avicenna give a comprehensive classified etiology of the sexual headache. The efficacy of some medicinal herbs used by him for sexual headache treatments, such as the analgesic effect of lavender, chamomile, and jasmine has been proved by current medicine; however, the knowledge of medieval physicians should be scientifically investigated even further to extend new remedial options for sexual headache.


Assuntos
Cefaleia/história , Fitoterapia/história , Comportamento Sexual/história , Cefaleia/diagnóstico , Cefaleia/terapia , História Medieval , Humanos , Pérsia , Médicos/história
14.
Materials (Basel) ; 17(9)2024 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-38730826

RESUMO

Woven flax-carbon hybrid polyamide biocomposites offer a blend of carbon fibers' mechanical strength and flax's environmental advantages, potentially developing material applications. This study investigated their thermal behavior, degradation kinetics, and durability to water uptake and relative humidity exposure and compared them with pure flax and carbon composites with the same matrix. The hybrid composite exhibited intermediate water/moisture absorption levels between pure flax and carbon composites, with 7.2% water absorption and 3.5% moisture absorption. It also displayed comparable thermal degradation resistance to the carbon composite, effectively maintaining its weight up to 300 °C. Further analysis revealed that the hybrid composite exhibited a decomposition energy of 268 kJ/mol, slightly lower than the carbon composite's value of 288.5 kJ/mol, indicating similar thermal stability. Isothermal lifetime estimation, employing the activation energy (Ed) and degree of conversion facilitated by the Model Free Kinetics method, indicated a 41% higher service life of the hybrid laminate at room temperature compared to the carbon laminate. These insights are crucial for understanding the industrial applications of these materials without compromising durability.

15.
Acta Med Hist Adriat ; 21(2): 307-319, 2024 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-38270069

RESUMO

Reviewing historical medical manuscripts shows that neurological disorders have been previously described in the Islamic Golden Age. Ibn Sina, also known as Avicenna (980-1037 AD), was one of the most renowned scientists during this period. He widely practiced medicine, especially those disorders related to neurology, neurosurgery, and psychiatry in conventional medicine. In his extant book al-Qanun fi al-Tibb (the Canon of Medicine), he claimed that some types of brain diseases can be related to the "maraqq" and called them maraqq-related disorders. From Avicenna's viewpoint, "maraqq" is considered a membranous structure in the abdomen. Ibn Sina has illustrated the association between the "maraqq" and the brain through some direct and indirect pathways. As a result, some disturbances in the "maraqq" can influence the brain, which can contribute to the pathogenesis of a number of brain diseases. Accordingly, those patients who regularly had gastrointestinal discomforts experienced a higher prevalence of headache, melancholia, and epilepsy. This study aimed to explore the relationship between abdominal and brain diseases from Avicenna's viewpoint. Furthermore, the definition, clinical manifestation, and therapeutic strategies of maraqq-related disorders were described.


Assuntos
Encefalopatias , Doenças do Sistema Nervoso , Neurocirurgia , Médicos , Psiquiatria , Humanos , Masculino , Doenças do Sistema Nervoso/complicações
16.
Polymers (Basel) ; 16(7)2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38611136

RESUMO

Cavitation erosion poses a significant challenge in fluid systems like hydraulic turbines and ship propellers due to pulsed pressure from collapsing vapor bubbles. To combat this, various materials and surface engineering methods are employed. In this study, nano and micro scale particles of silicon carbide (SiC) or boron carbide (B4C) were incorporated as reinforcement at 6% and 12% ratios, owing to their exceptional resistance to abrasive wear and high hardness. Microparticles were incorporated to assess the damage incurred during the tests in comparison to nanoparticles. Wear tests were conducted on both bulk samples and coated aluminum sheets with a 1mm of composite. Additionally, cavitation tests were performed on coated aluminum tips until stability of mass loss was achieved. The results indicated a distinct wear behavior between the coatings and the bulk samples. Overall, wear tended to be higher for the coated samples with nanocomposites than bulk, except for the nano-composite material containing 12% SiC and pure resin. With the coatings, higher percentages of nanometric particles correlated with increased wear. The coefficient of friction remained within the range of 0.4 to 0.5 for the coatings. Regarding the accumulated erosion in the cavitation tests for 100 min, it was observed that for all nanocomposite materials, it was lower than in pure resin. Particularly, the composite with 6% B4C was slightly lower than the rest. In addition, the erosion rate was also lower for the composites.

17.
Materials (Basel) ; 17(9)2024 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-38730861

RESUMO

Because of the high demand for carbon fiber reinforced polymer (CFRP) materials across all industries, the reuse and/or recycling of these materials (rCFRP) is necessary in order to meet the principles of the circular economy, including recycling and reuse. The objective of this study is to estimate the lifespan of thermoplastic matrix composite materials reinforced with waste materials (CFRP), which undergo only a mechanical cutting process. This estimation is carried out through the thermal decomposition of polymers, including polymer matrix composite materials, which is a complex process due to the numerous reactions involved. Some authors calculate these kinetic parameters using thermogravimetric analysis (TGA) as it is a quick method, and it allows the identification of gases released during decomposition, provided that the equipment is prepared for it. This study includes a comparison between polyamides 11 and 12, as well as between polyamide composite materials with carbon fiber (CF) and polyamides reinforced with CF/epoxy composite material. The latter is treated with plasma to improve adhesion with polyamides. The behavior of weight as a function of temperature was studied at speeds of 3, 6, 10, 13, 17, and 20 °C/min, finding stability of the polyamides up to a temperature of 400 °C, which was consistent with the analysis by mass spectroscopy, where gas evolution is evident after 400 °C. The estimation of the lifespan was carried out using two different methods including the Toop equation and the free kinetics model (MFK). The energy of the decomposition process was determined using the MFK model, which establishes the energy as a function of the degree of conversion. It is estimated that at 5% decomposition, mechanical properties are lost.

18.
Nat Commun ; 15(1): 2291, 2024 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-38480685

RESUMO

Poor diets are a leading cause of morbidity and mortality. Exposure to low-quality food environments saturated with fast food outlets is hypothesized to negatively impact diet. However, food environment research has predominantly focused on static food environments around home neighborhoods and generated mixed findings. In this work, we leverage population-scale mobility data in the U.S. to examine 62M people's visits to food outlets and evaluate how food choice is influenced by the food environments people are exposed to as they move through their daily routines. We find that a 10% increase in exposure to fast food outlets in mobile environments increases individuals' odds of visitation by 20%. Using our results, we simulate multiple policy strategies for intervening on food environments to reduce fast-food outlet visits. This analysis suggests that optimal interventions are informed by spatial, temporal, and behavioral features and could have 2x to 4x larger effect than traditional interventions focused on home food environments.


Assuntos
Dieta , Fast Foods , Humanos , Fast Foods/efeitos adversos , Características de Residência
19.
Arch Iran Med ; 27(4): 183-190, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38685844

RESUMO

BACKGROUND: Data on the epidemiology of inflammatory bowel disease (IBD) in the Middle East are scarce. We aimed to describe the clinical phenotype, disease course, and medication usage of IBD cases from Iran in the Middle East. METHODS: We conducted a cross-sectional study of registered IBD patients in the Iranian Registry of Crohn's and Colitis (IRCC) from 2017 until 2022. We collected information on demographic characteristics, past medical history, family history, disease extent and location, extra-intestinal manifestations, IBD medications, and activity using the IBD-control-8 questionnaire and the Manitoba IBD index, admissions history, history of colon cancer, and IBD-related surgeries. RESULTS: In total, 9746 patients with ulcerative colitis (UC) (n=7793), and Crohn's disease (CD) (n=1953) were reported. The UC to CD ratio was 3.99. The median age at diagnosis was 29.2 (IQR: 22.6,37.6) and 27.6 (IQR: 20.6,37.6) for patients with UC and CD, respectively. The male-to-female ratio was 1.28 in CD patients. A positive family history was observed in 17.9% of UC patients. The majority of UC patients had pancolitis (47%). Ileocolonic involvement was the most common type of involvement in CD patients (43.7%), and the prevalence of stricturing behavior was 4.6%. A prevalence of 0.3% was observed for colorectal cancer among patients with UC. Moreover,15.2% of UC patients and 38.4% of CD patients had been treated with anti-tumor necrosis factor (anti-TNF). CONCLUSION: In this national registry-based study, there are significant differences in some clinical phenotypes such as the prevalence of extra-intestinal manifestations and treatment strategies such as biological use in different geographical locations.


Assuntos
Colite Ulcerativa , Doença de Crohn , Fenótipo , Sistema de Registros , Humanos , Irã (Geográfico)/epidemiologia , Masculino , Feminino , Estudos Transversais , Adulto , Doença de Crohn/epidemiologia , Colite Ulcerativa/epidemiologia , Adulto Jovem , Pessoa de Meia-Idade , Adolescente
20.
Brain Connect ; 13(2): 64-79, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36006366

RESUMO

Despite the explosive growth of neuroimaging studies aimed at analyzing the brain as a complex system, critical methodological gaps remain to be addressed. Most tools currently used for analyzing network data of the brain are univariate in nature and are based on assumptions borne out of previous techniques not directly related to the big and complex data of the brain. Although graph-based methods have shown great promise, the development of principled multivariate models to address inherent limitations of graph-based methods, such as their dependence on network size and degree distributions, and to allow assessing the effects of multiple phenotypes on the brain and simulating brain networks has largely lagged behind. Although some studies have been made in developing multivariate frameworks to fill this gap, in the absence of a "gold-standard" method or guidelines, choosing the most appropriate method for each study can be another critical challenge for investigators in this multidisciplinary field. Here, we briefly introduce important multivariate methods for brain network analyses in two main categories: data-driven and model-based methods. We discuss whether/how such methods are suited for examining connectivity (edge-level), topology (system-level), or both. This review will aid in choosing an appropriate multivariate method with respect to variables such as network type, number of subjects and brain regions included, and the interest in connectivity, topology, or both. This review is aimed to be accessible to investigators from different backgrounds, with a focus on applications in brain network studies, though the methods may be applicable in other areas too. Impact statement As the U.S. National Institute of Health notes, the rich biomedical data can greatly improve our knowledge of human health if new analytical tools are developed, and their applications are broadly disseminated. A major challenge in analyzing the brain as a complex system is about developing parsimonious multivariate methods, and particularly choosing the most appropriate one among the existing methods with respect to the study variables in this multidisciplinary field. This study provides a review on the most important multivariate methods to aid in helping the most appropriate ones with respect to the desired variables for each study.


Assuntos
Encéfalo , Imageamento por Ressonância Magnética , Humanos , Encéfalo/diagnóstico por imagem , Neuroimagem/métodos , Rede Nervosa
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