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1.
Can J Surg ; 67(3): E188-E197, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38692681

RESUMO

BACKGROUND: The evidence on the benefits and drawbacks of involving neurosurgical residents in the care of patients who undergo neurosurgical procedures is heterogeneous. We assessed the effect of neurosurgical residency programs on the outcomes of such patients in a large single-payer public health care system. METHODS: Ten population-based cohorts of adult patients in Ontario who received neurosurgical care from 2013 to 2017 were identified on the basis of procedural codes, and the cohorts were followed in administrative health data sources. Patient outcomes by the status of the treating hospital (with or without a neurosurgical residency program) within each cohort were compared with models adjusted for a priori confounders and with adjusted multilevel models (MLMs) to also account for hospital-level factors. RESULTS: A total of 46 608 neurosurgical procedures were included. Operative time was 8%-30% longer in hospitals with neurosurgical residency programs in 9 out of 10 cohorts. Thirty-day mortality was lower in hospitals with neurosurgical residency programs for aneurysm repair (odds ratio [OR] 0.30, 95% confidence interval [CI] 0.20-0.44), cerebrospinal fluid shunting (OR 0.52, 95% CI 0.34-0.79), intracerebral hemorrhage evacuation (OR 0.66, 95% CI 0.52-0.84), and posterior lumbar decompression (OR 0.32, 95% CI 0.15-0.65) in adjusted models. The mortality rates remained significantly different only for aneurysm repair (OR 0.19, 95% CI 0.05-0.69) and cerebrospinal shunting (OR 0.42, 95% CI 0.21-0.85) in MLMs. Length of stay was mostly shorter in hospitals with neurosurgical residents, but this finding did not persist in MLMs. Thirty-day reoperation rates did not differ between hospital types in MLMs. For 30-day readmission rates, only extracerebral hematoma decompression was significant in MLMs (OR 1.41, 95% CI 1.07-1.87). CONCLUSION: Hospitals with neurosurgical residents had longer operative times with similar to better outcomes. Most, but not all, of the differences between hospitals with and without residency programs were explained by hospital-level variables rather than direct effects of residents.


Assuntos
Internato e Residência , Procedimentos Neurocirúrgicos , Humanos , Internato e Residência/estatística & dados numéricos , Procedimentos Neurocirúrgicos/educação , Procedimentos Neurocirúrgicos/estatística & dados numéricos , Masculino , Feminino , Ontário , Pessoa de Meia-Idade , Estudos de Coortes , Neurocirurgia/educação , Adulto , Idoso , Duração da Cirurgia
2.
Magn Reson Imaging ; 109: 286-293, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38531463

RESUMO

INTRODUCTION: The relationship between brain lesions and stroke outcomes is crucial for advancing patient prognosis and developing effective therapies. Stroke is a leading cause of disability worldwide, and it is important to understand the neurological basis of its varied symptomatology. Lesion-symptom mapping (LSM) methods provide a means to identify brain areas that are strongly associated with specific symptoms. However, inner variations in LSM methods can yield different results. To address this, our study aimed to characterize the lesion-symptom mapping variability using three different LSM methods. Specifically, we sought to determine a lesion symptom core across LSM approaches enhancing the robustness of the analysis and removing potential spatial bias. MATERIAL & METHODS: A cohort consisting of 35 patients with either right- or left-sided middle cerebral artery strokes were enrolled and evaluated using the NIHSS at 24 h post-stroke. Anatomical T1w MRI scans were also obtained 24 h post-stroke. Lesion masks were segmented manually and three distinctive LSM methods were implemented: ROI correlation-based, univariate, and multivariate approaches. RESULTS: The results of the LSM analyses showed substantial spatial differences in the extension of each of the three lesion maps. However, upon overlaying all three lesion-symptom maps, a consistent lesion core emerged, corresponding to the territory associated with elevated NIHSS scores. This finding not only enhances the spatial accuracy of the lesion map but also underscores its clinical relevance. CONCLUSION: This study underscores the significance of exploring complementary LSM approaches to investigate the association between brain lesions and stroke outcomes. By utilizing multiple methods, we can increase the robustness of our results, effectively addressing and neutralizing potential spatial bias introduced by each individual method. Such an approach holds promise for enhancing our understanding of stroke pathophysiology and optimizing patient care strategies.


Assuntos
Mapeamento Encefálico , Acidente Vascular Cerebral , Humanos , Mapeamento Encefálico/métodos , Acidente Vascular Cerebral/diagnóstico por imagem , Acidente Vascular Cerebral/patologia , Encéfalo/patologia , Imageamento por Ressonância Magnética , Infarto da Artéria Cerebral Média
3.
Am J Physiol Regul Integr Comp Physiol ; 326(5): R346-R356, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38406844

RESUMO

The aim of this study was to investigate how aging affects blood flow and structure of the brain. It was hypothesized older individuals would have lower gray matter volume (GMV), resting cerebral blood flow (CBF0), and depressed responses to isometabolic and neurometabolic stimuli. In addition, increased carotid-femoral pulse-wave velocity (PWV), carotid intima-media thickness (IMT), and decreased brachial flow-mediated dilation (FMD) would be associated with lower CBF0, cerebrovascular reactivity (CVR), and GMV. Brain scans (magnetic resonance imaging) and cardiovascular examinations were conducted in young (age = 24 ± 3 yr, range = 22-28 yr; n = 13) and old (age = 71 ± 4 yr; range = 67-82 yr, n = 14) participants, and CBF0, CVR [isometabolic % blood oxygen level-dependent (BOLD) in response to a breath hold (BH)], brain activation patterns during a working memory task (neurometabolic %BOLD response to N-back trial), GMV, PWV, IMT, and FMD were measured. CBF0 and to a lesser extent CVRBH were lower in the old group (P ≤ 0.050); however, the increase in the %BOLD response to the memory task was not blunted (P ≥ 0.2867). Age-related differential activation patterns during the working memory task were characterized by disinhibition of the default mode network in the old group (P < 0.0001). Linear regression analyses revealed PWV, and IMT were negatively correlated with CBF0, CVRBH, and GMV across age groups, but within the old group alone only the relationships between PWV-CVRBH and IMT-GMV remained significant (P ≤ 0.0183). These findings suggest the impacts of age on cerebral %BOLD responses are stimulus specific, brain aging involves alterations in cerebrovascular and possibly neurocognitive control, and arterial stiffening and wall thickening may serve a role in cerebrovascular aging.NEW & NOTEWORTHY Cerebral perfusion was lower in old versus young adults. %Blood oxygen level-dependent (BOLD) responses to an isometabolic stimulus and gray matter volume were decreased in old versus young adults and associated with arterial stiffening and wall thickening. The increased %BOLD response to a neurometabolic stimulus appeared unaffected by age; however, the old group displayed disinhibition of the default mode network during the stimulus. Thus, age-related alterations in cerebral %BOLD responses were stimulus specific and related to arterial remodeling.


Assuntos
Espessura Intima-Media Carotídea , Imageamento por Ressonância Magnética , Adulto Jovem , Humanos , Adulto , Idoso , Imageamento por Ressonância Magnética/métodos , Encéfalo/fisiologia , Envelhecimento , Circulação Cerebrovascular/fisiologia , Atrofia
4.
eNeuro ; 11(2)2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38238081

RESUMO

An important aspect of motor function is our ability to rapidly generate goal-directed corrections for disturbances to the limb or behavioral goal. The primary motor cortex (M1) is a key region involved in processing feedback for rapid motor corrections, yet we know little about how M1 circuits are recruited by different sources of sensory feedback to make rapid corrections. We trained two male monkeys (Macaca mulatta) to make goal-directed reaches and on random trials introduced different sensory errors by either jumping the visual location of the goal (goal jump), jumping the visual location of the hand (cursor jump), or applying a mechanical load to displace the hand (proprioceptive feedback). Sensory perturbations evoked a broad response in M1 with ∼73% of neurons (n = 257) responding to at least one of the sensory perturbations. Feedback responses were also similar as response ranges between the goal and cursor jumps were highly correlated (range of r = [0.91, 0.97]) as were the response ranges between the mechanical loads and the visual perturbations (range of r = [0.68, 0.86]). Lastly, we identified the neural subspace each perturbation response resided in and found a strong overlap between the two visual perturbations (range of overlap index, 0.73-0.89) and between the mechanical loads and visual perturbations (range of overlap index, 0.36-0.47) indicating each perturbation evoked similar structure of activity at the population level. Collectively, our results indicate rapid responses to errors from different sensory sources target similar overlapping circuits in M1.


Assuntos
Córtex Motor , Desempenho Psicomotor , Masculino , Humanos , Desempenho Psicomotor/fisiologia , Córtex Motor/fisiologia , Mãos/fisiologia , Propriocepção/fisiologia , Retroalimentação Sensorial/fisiologia
5.
Plant Methods ; 19(1): 64, 2023 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-37391797

RESUMO

BACKGROUND: Modern computational modeling could provide the key to obtaining new insights into the mechanisms of maize stalk failure as well as suggesting new ways to improve stalk strength. However, a complete set of mechanical properties of maize tissues is required to enable computational modeling of maize stems. This study developed two compression test methods for obtaining the longitudinal modulus of elasticity of both rind and pith tissues, assessed the influence of water content on tissue properties, and investigated the relationship between rind modulus and pith modulus. These methods involved uniform 5-7 cm segments of maize stems which were scanned using a flatbed scanner then tested in compression using a universal testing machine in both intact and dissected (rind-only and pith-only) states. RESULTS: The modulus of elasticity of pith tissues was highest for fully turgid specimens and decreased as water was removed from the specimens. Water content was negatively correlated with the modulus of elasticity of the rind. Rind and pith tissues were found to be weakly correlated. The median ratio of rind modulus to pith modulus was found to be 17. Of the two methods investigated, the pith-only specimen preparation was found to be simple reliable while the rind-only method was found to be adversely affected by lateral bowing of the specimen. CONCLUSIONS: Researchers can use the information in this paper to improve computational models of maize stems in three ways: (1) by incorporating realistic values of the longitudinal modulus of elasticity of pith and rind tissues; (2) by selecting pith and rind properties that match empirically observed ratios; and (3) by incorporating appropriate dependencies between these material properties and water content. From an experimental perspective, the intact/pith-only experimental method outlined in this paper is simpler than previously reported methods and provides reliable estimates of both pith and rind modulus of elasticity values. Further research using this measurement method is recommended to more clearly understand the influence of water content and turgor pressure on tissue properties.

6.
Proc Natl Acad Sci U S A ; 120(27): e2220570120, 2023 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-37364097

RESUMO

Understanding the origins of variation in agricultural pathogens is of fundamental interest and practical importance, especially for diseases that threaten food security. Fusarium oxysporum is among the most important of soil-borne pathogens, with a global distribution and an extensive host range. The pathogen is considered to be asexual, with horizontal transfer of chromosomes providing an analog of assortment by meiotic recombination. Here, we challenge those assumptions based on the results of population genomic analyses, describing the pathogen's diversity and inferring its origins and functional consequences in the context of a single, long-standing agricultural system. We identify simultaneously low nucleotide distance among strains, and unexpectedly high levels of genetic and genomic variability. We determine that these features arise from a combination of genome-scale recombination, best explained by widespread sexual reproduction, and presence-absence variation consistent with chromosomal rearrangement. Pangenome analyses document an accessory genome more than twice the size of the core genome, with contrasting evolutionary dynamics. The core genome is stable, with low diversity and high genetic differentiation across geographic space, while the accessory genome is paradoxically more diverse and unstable but with lower genetic differentiation and hallmarks of contemporary gene flow at local scales. We suggest a model in which episodic sexual reproduction generates haplotypes that are selected and then maintained through clone-like dynamics, followed by contemporary genomic rearrangements that reassort the accessory genome among sympatric strains. Taken together, these processes contribute unique genome content, including reassortment of virulence determinants that may explain observed variation in pathogenic potential.


Assuntos
Fusarium , Fusarium/genética , Especificidade de Hospedeiro , Genômica , Agricultura , Doenças das Plantas/genética
7.
Front Psychiatry ; 14: 1050530, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36970278

RESUMO

Background: Obsessive-compulsive disorder (OCD) is a debilitating mental health disorder with current psychotherapeutic treatments, while somewhat effective, yielding low accessibility and scalability. A lack of knowledge regarding the neural pathology of OCD may be hindering the development of innovative treatments. Previous research has observed baseline brain activation patterns in OCD patients, elucidating some understanding of the implications. However, by using neuroimaging to observe the effects of treatment on brain activation, a more complete picture of OCD can be drawn. Currently, the gold standard treatment is cognitive behavioral therapy (CBT). However, CBT is often inaccessible, time-consuming, and costly. Fortunately, it can be effectively delivered electronically (e-CBT). Objectives: This pilot study implemented an e-CBT program for OCD and observed its effects on cortical activation levels during a symptom provocation task. It was hypothesized that abnormal activations could be attenuated following treatment. Methods: OCD patients completed a 16-week e-CBT program administered through an online platform, mirroring in-person content. Treatment efficacy was evaluated using behavioral questionnaires and neuroimaging. Activation levels were assessed at the resting state and during the symptom provocation task. Results: In this pilot, seven participants completed the program, with significant improvements (p < 0.05) observed between baseline and post-treatment for symptom severity and levels of functioning. No statistically significant (p = 0.07) improvement was observed in the quality of life. Participants had mostly positive qualitative feedback, citing accessibility benefits, comprehensive formatting, and relatable content. No significant changes in cortical activation were observed between baseline and post-treatment. Conclusion: This project sheds light on the application of e-CBT as a tool to evaluate the effects of treatment on cortical activation, setting the stage for a larger-scale study. The program showed great promise in feasibility and effectiveness. While there were no significant findings regarding changes in cortical activation, the trends were in agreeance with previous literature, suggesting future work could provide insight into whether e-CBT offers comparable cortical effects to in-person psychotherapy. Applying a greater knowledge of the neural mechanisms of action in OCD can help develop novel treatment plans in the future.

8.
Front Comput Neurosci ; 17: 1199736, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38260713

RESUMO

Introduction: Advances in machine learning (ML) methodologies, combined with multidisciplinary collaborations across biological and physical sciences, has the potential to propel drug discovery and development. Open Science fosters this collaboration by releasing datasets and methods into the public space; however, further education and widespread acceptance and adoption of Open Science approaches are necessary to tackle the plethora of known disease states. Motivation: In addition to providing much needed insights into potential therapeutic protein targets, we also aim to demonstrate that small patient datasets have the potential to provide insights that usually require many samples (>5,000). There are many such datasets available and novel advancements in ML can provide valuable insights from these patient datasets. Problem statement: Using a public dataset made available by patient advocacy group AnswerALS and a multidisciplinary Open Science approach with a systems biology augmented ML technology, we aim to validate previously reported drug targets in ALS and provide novel insights about ALS subpopulations and potential drug targets using a unique combination of ML methods and graph theory. Methodology: We use NetraAI to generate hypotheses about specific patient subpopulations, which were then refined and validated through a combination of ML techniques, systems biology methods, and expert input. Results: We extracted 8 target classes, each comprising of several genes that shed light into ALS pathophysiology and represent new avenues for treatment. These target classes are broadly categorized as inflammation, epigenetic, heat shock, neuromuscular junction, autophagy, apoptosis, axonal transport, and excitotoxicity. These findings are not mutually exclusive, and instead represent a systematic view of ALS pathophysiology. Based on these findings, we suggest that simultaneous targeting of ALS has the potential to mitigate ALS progression, with the plausibility of maintaining and sustaining an improved quality of life (QoL) for ALS patients. Even further, we identified subpopulations based on disease onset. Conclusion: In the spirit of Open Science, this work aims to bridge the knowledge gap in ALS pathophysiology to aid in diagnostic, prognostic, and therapeutic strategies and pave the way for the development of personalized treatments tailored to the individual's needs.

9.
Transl Stroke Res ; 2022 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-36542292

RESUMO

Stroke is a devastating disease that results in neurological deficits and represents a leading cause of death and disability worldwide. Following a stroke, there is a degree of spontaneous recovery of function, the neural basis of which is of great interest among clinicians in their efforts to reduce disability following stroke and enhance rehabilitation. Conventionally, work on spontaneous recovery has tended to focus on the neural reorganization of motor cortical regions, with comparably little attention being paid to changes in non-motor regions and how these relate to recovery. Here we show, using structural neuroimaging in a macaque stroke model (N = 31) and by exploiting individual differences in spontaneous behavioural recovery, that the preservation of regions in the parietal and temporal cortices predict animal recovery. To characterize recovery, we performed a clustering analysis using Non-Human Primate Stroke Scale (NHPSS) scores and identified a good versus poor recovery group. By comparing the preservation of brain volumes in the two groups, we found that brain areas in integrity of brain areas in parietal, temporal and somatosensory cortex were associated with better recovery. In addition, a decoding approach performed across all subjects revealed that the preservation of specific brain regions in the parietal, somatosensory and medial frontal cortex predicted recovery. Together, these findings highlight the importance of parietal and temporal regions in spontaneous behavioural recovery.

10.
J R Soc Interface ; 19(191): 20220257, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35642425

RESUMO

Intracranial cerebrospinal and interstitial fluid (ISF) flow and solute transport have important clinical implications, but limited in vivo access to the brain interior leaves gaping holes in human understanding of the nature of these neurophysiological phenomena. Models can address some gaps, but only insofar as model inputs are accurate. We perform a sensitivity analysis using a Monte Carlo approach on a lumped-parameter network model of cerebrospinal and ISF in perivascular and extracellular spaces in the murine brain. We place bounds on model predictions given the uncertainty in input parameters. Péclet numbers for transport in penetrating perivascular spaces (PVSs) and within the parenchyma are separated by at least two orders of magnitude. Low permeability in penetrating PVSs requires unrealistically large driving pressure and/or results in poor perfusion and are deemed unlikely. The model is most sensitive to the permeability of penetrating PVSs, a parameter whose value is largely unknown, highlighting an important direction for future experiments. Until the value of the permeability of penetrating PVSs is more accurately measured, the uncertainty of any model that includes flow in penetrating PVSs is so large that absolute numbers have little meaning and practical application is limited.


Assuntos
Encéfalo , Líquido Extracelular , Animais , Encéfalo/fisiologia , Líquido Extracelular/metabolismo , Humanos , Camundongos
11.
Alzheimers Dement (N Y) ; 8(1): e12289, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35415210

RESUMO

Monkeys are becoming important translational models of neurodegenerative disease. To facilitate model development, we measured cerebrospinal fluid (CSF) concentrations of key biomarkers in healthy male and female cynomolgus and rhesus macaques. Amyloid beta (Aß40, Aß42), tau (total tau [t-tau], phosphorylated tau [pThr181]), and neurofilament light (NfL) concentrations were measured in CSF of 82 laboratory-housed, experimentally naïve cynomolgus (n = 33) and rhesus (n = 49) macaques. Aß40 and Aß42 were significantly higher in rhesus, and female rhesus were higher than males. NfL and t-tau were higher in males, and NfL was higher in rhesus macaques. p-tau was not affected by species or sex. We also examined whether sample location (lumbar or cisterna puncture) affected concentrations. Sample acquisition site only affected NfL, which was higher in CSF from lumbar puncture compared to cisterna magna puncture. Establishing normative biomarker values for laboratory-housed macaque monkeys provides an important resource by which to compare to monkey models of neurodegenerative diseases.

12.
Biophys J ; 121(6): 865-868, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35235769

Assuntos
Parede Celular
13.
Curr Protoc ; 2(2): e371, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35179832

RESUMO

Here we present the approach used to develop the INCREASE "Intelligent Chickpea" Collections, from analysis of the information on the life history and population structure of chickpea germplasm, the availability of genomic and genetic resources, the identification of key phenotypic traits and methodologies to characterize chickpea. We present two phenotypic protocols within H2O20 Project INCREASE to characterize, develop, and maintain chickpea single-seed-descent (SSD) line collections. Such protocols and related genetic resource data from the project will be available for the legume community to apply the standardized approaches to develop Chickpea Intelligent Collections further or for multiplication/seed-increase purposes. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Characterization of chickpea seeds for seed-trait descriptors Basic Protocol 2: Characterization of chickpea lines for plant-trait descriptors specific for primary seed increase.


Assuntos
Cicer , Fabaceae , Cicer/genética , Genômica , Fenótipo , Sementes/genética
14.
Plant Cell Environ ; 45(5): 1573-1583, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35141927

RESUMO

Plant mechanical failure (lodging) causes global yield losses of 7%-66% in cereal crops. We have previously shown that the above-ground nodal roots (brace roots) in maize are critical for anchorage. However, it is unknown how brace root phenotypes vary across genotypes and the functional consequence of this variation. This study quantifies the contribution of brace roots to anchorage, brace root traits, plant height, and root lodging susceptibility in 52 maize inbred lines. We show that the contribution of brace roots to anchorage and root lodging susceptibility varies among genotypes and this contribution can be explained by plant architectural variation. Additionally, supervised machine learning models were developed and show that multiple plant architectural phenotypes can predict the contribution of brace roots to anchorage and root lodging susceptibility. Together these data define the plant architectures that are important in lodging resistance and show that the contribution of brace roots to anchorage is a good proxy for root lodging susceptibility.


Assuntos
Raízes de Plantas , Zea mays , Produtos Agrícolas , Genótipo , Fenótipo , Raízes de Plantas/genética , Zea mays/genética
15.
Brain Imaging Behav ; 16(4): 1575-1591, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35092574

RESUMO

The purpose of this study was to determine if differences in functional connectivity strength (FCS) with age were confounded by vascular parameters including resting cerebral blood flow (CBF0), cerebrovascular reactivity (CVR), and BOLD-CBF coupling. Neuroimaging data were collected from 13 younger adults (24 ± 2 years) and 14 older adults (71 ± 4 years). A dual-echo resting state pseudo-continuous arterial spin labeling sequence was performed, as well as a BOLD breath-hold protocol. A group independent component analysis was used to identify networks, which were amalgamated into a region of interest (ROI). Within the ROI, FC strength (FCS) was computed for all voxels and compared across the groups. CBF0, CVR and BOLD-CBF coupling were examined within voxels where FCS was different between young and older adults. FCS was greater in old compared to young (P = 0.001). When the effect of CBF0, CVR and BOLD-CBF coupling on FCS was examined, BOLD-CBF coupling had a significant effect (P = 0.003) and group differences in FCS were not present once all vascular parameters were considered in the statistical model (P = 0.07). These findings indicate that future studies of FCS should consider vascular physiological markers in order to improve our understanding of aging processes on brain connectivity.


Assuntos
Circulação Cerebrovascular , Imageamento por Ressonância Magnética , Idoso , Encéfalo/fisiologia , Circulação Cerebrovascular/fisiologia , Humanos , Imageamento por Ressonância Magnética/métodos , Descanso/fisiologia , Marcadores de Spin
16.
Sci Rep ; 12(1): 720, 2022 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-35031627

RESUMO

The maize (Zea mays) stem is a biological structure that must balance both biotic and structural load bearing duties. These competing requirements are particularly relevant in the design of new bioenergy crops. Although increased stem digestibility is typically associated with a lower structural strength and higher propensity for lodging, with the right balance between structural and biological activities it may be possible to design crops that are high-yielding and have digestible biomass. This study investigates the hypothesis that geometric factors are much more influential in determining structural strength than tissue properties. To study these influences, both physical and in silico experiments were used. First, maize stems were tested in three-point bending. Specimen-specific finite element models were created based on x-ray computed tomography scans. Models were validated by comparison with experimental data. Sensitivity analyses were used to assess the influence of structural parameters such as geometric and material properties. As hypothesized, geometry was found to have a much stronger influence on structural stability than material properties. This information reinforces the notion that deficiencies in tissue strength could be offset by manipulation of stalk morphology, thus allowing the creation of stalks which are both resilient and digestible.


Assuntos
Fenômenos Biomecânicos , Produtos Agrícolas , Zea mays/anatomia & histologia , Zea mays/fisiologia , Biocombustíveis , Biomassa , Simulação por Computador , Maleabilidade , Resistência à Tração , Tomografia Computadorizada por Raios X
17.
Syst Appl Microbiol ; 45(1): 126279, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34839036

RESUMO

Chickpea is the third most important grain legume worldwide. This is due in part to its high protein content that results from its ability to acquire bioavailable nitrogen when colonized by diverse, nitrogen fixing Mesorhizobium species. However, the diversity and distribution of mesorhizobia communities may depend on their adaptation to soil conditions. Therefore, this study was initiated in order to isolate and investigate the diversity and taxonomic identities of chickpea-nodulating Mesorhizobium species from low pH soils of Ethiopia. A total of 81 rhizobia strains were isolated from chickpea nodules harvested from low pH soils throughout Ethiopia, and their genomes were sequenced and assembled. Considering a representative set of the best-sequenced 81 genomes, the average sequence depth was 30X, with estimated average genome sizes of approximately 7 Mbp. Annotation of the assembled genome predicted an average of 7,453 protein-coding genes. Concatenation of 400 universal PhyloPhlAn conserved genes present in the genomes of all 81 strains allowed detailed phylogenetic analysis, from which eight well-supported species were identified, including M.opportunistum, M.australicum, Mesorhizobium sp. LSJC280BOO, M.wenxiniae, M.amorphae, M.loti and M.plurifarium, as well as a novel species. Phylogenetic reconstructions based on the symbiosis-related (nodC and nifH) genes were different from the core genes and consistent with horizontal transfer of the symbiotic island. The two major genomic groups, M.plurifarium and M.loti, were widely distributed in almost all the sites. The geographic pattern of genomic diversity indicated there was no relationship between geographic and genetic distance (r = 0.01, p > 0.01). In conclusion, low pH soils in Ethiopia harbored a diverse group of Mesorhizobium species, several of which were not previously known to nodulate chickpea.


Assuntos
Cicer , Mesorhizobium , DNA Bacteriano , Etiópia , Genômica , Concentração de Íons de Hidrogênio , Mesorhizobium/genética , Filogenia , RNA Ribossômico 16S , Análise de Sequência de DNA , Solo , Simbiose
18.
Plant Methods ; 17(1): 101, 2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34620195

RESUMO

BACKGROUND: Flexural three-point bending tests are useful for characterizing the mechanical properties of plant stems. These tests can be performed with minimal sample preparation, thus allowing tests to be performed relatively quickly. The best-practice for such tests involves long spans with supports and load placed at nodes. This approach typically provides only one flexural stiffness measurement per specimen. However, by combining flexural tests with analytic equations, it is possible to solve for the mechanical characteristics of individual stem segments. RESULTS: A method is presented for using flexural tests to obtain estimates of flexural stiffness of individual segments. This method pairs physical test data with analytic models to obtain a system of equations. The solution of this system of equations provides values of flexural stiffness for individual stalk segments. Uncertainty in the solved values for flexural stiffness were found to be strongly dependent upon measurement errors. Row-wise scaling of the system of equations reduced the influence of measurement error. Of many possible test combinations, the most advantageous set of tests for performing these measurements were identified. Relationships between measurement uncertainty and solution uncertainty were provided for two different testing methods. CONCLUSIONS: The methods presented in this paper can be used to measure the axial variation in flexural stiffness of plant stem segments. However, care must be taken to account for the influence of measurement error as the individual segment method amplifies measurement error. An alternative method involving aggregate flexural stiffness values does not amplify measurement error, but provides lower spatial resolution.

19.
JMIR Res Protoc ; 10(9): e30726, 2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34348889

RESUMO

BACKGROUND: Obsessive-compulsive disorder (OCD) is a debilitating and prevalent anxiety disorder. Although the basal ganglia and frontal cortex are the brain regions that are most commonly hypothesized to be involved in OCD, the exact pathophysiology is unknown. By observing the effects of proven treatments on brain activation levels, the cause of OCD can be better understood. Currently, the gold standard treatment for OCD is cognitive behavioral therapy (CBT) with exposure and response prevention. However, this is often temporally and geographically inaccessible, time consuming, and costly. Fortunately, CBT can be effectively delivered using the internet (electronically delivered CBT [e-CBT]) because of its structured nature, thus addressing these barriers. OBJECTIVE: The aims of this study are to implement an e-CBT program for OCD and to observe its effects on brain activation levels using functional magnetic resonance imaging (MRI). It is hypothesized that brain activation levels in the basal ganglia and frontal cortex will decrease after treatment. METHODS: Individuals with OCD will be offered a 16-week e-CBT program with exposure and response prevention mirroring in-person CBT content and administered through a secure web-based platform. The efficacy of the treatment will be evaluated using clinically validated symptomology questionnaires at baseline, at week 8, and after treatment (week 16). Using functional MRI at baseline and after treatment, brain activation levels will be assessed in the resting state and while exposed to anxiety-inducing images (eg, dirty dishes if cleanliness is an obsession). The effects of treatment on brain activation levels and the correlation between symptom changes and activation levels will be analyzed. RESULTS: The study received initial ethics approval in December 2020, and participant recruitment began in January 2021. Participant recruitment has been conducted through social media advertisements, physical advertisements, and physician referrals. To date, 5 participants have been recruited. Data collection is expected to conclude by January 2022, and data analysis is expected to be completed by February 2022. CONCLUSIONS: The findings from this study can further our understanding of the causation of OCD and help develop more effective treatments for this disorder. TRIAL REGISTRATION: ClinicalTrials.gov NCT04630197; https://clinicaltrials.gov/ct2/show/NCT04630197. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/30726.

20.
Plant J ; 108(3): 646-660, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34427014

RESUMO

Food legumes are crucial for all agriculture-related societal challenges, including climate change mitigation, agrobiodiversity conservation, sustainable agriculture, food security and human health. The transition to plant-based diets, largely based on food legumes, could present major opportunities for adaptation and mitigation, generating significant co-benefits for human health. The characterization, maintenance and exploitation of food-legume genetic resources, to date largely unexploited, form the core development of both sustainable agriculture and a healthy food system. INCREASE will implement, on chickpea (Cicer arietinum), common bean (Phaseolus vulgaris), lentil (Lens culinaris) and lupin (Lupinus albus and L. mutabilis), a new approach to conserve, manage and characterize genetic resources. Intelligent Collections, consisting of nested core collections composed of single-seed descent-purified accessions (i.e., inbred lines), will be developed, exploiting germplasm available both from genebanks and on-farm and subjected to different levels of genotypic and phenotypic characterization. Phenotyping and gene discovery activities will meet, via a participatory approach, the needs of various actors, including breeders, scientists, farmers and agri-food and non-food industries, exploiting also the power of massive metabolomics and transcriptomics and of artificial intelligence and smart tools. Moreover, INCREASE will test, with a citizen science experiment, an innovative system of conservation and use of genetic resources based on a decentralized approach for data management and dynamic conservation. By promoting the use of food legumes, improving their quality, adaptation and yield and boosting the competitiveness of the agriculture and food sector, the INCREASE strategy will have a major impact on economy and society and represents a case study of integrative and participatory approaches towards conservation and exploitation of crop genetic resources.


Assuntos
Produtos Agrícolas/genética , Fabaceae/genética , Banco de Sementes , Bases de Dados Genéticas , Europa (Continente) , Genótipo , Cooperação Internacional , Sementes/genética
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